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Draft SEIR AppendixTEMECULA REGIONAL HOSPITAL October 2007Prepared for: City of Temecula Appendix to Draft Supplemental Environmental Impact Report SCH # 2005031017 Appendix A Notice of Preparation of Supplemental Environmental Impact Report Appendix B Responses to Notice of Preparation Appendix C Soil Vapor Survey Prepared by: SCS Engineers 8799 Balboa Avenue, Suite 290 San Diego, California 92123 (858) 571-5500 October 24, 2007 Project Number: 01207522.00 This document was prepared for use only by the client, only for the purpose stated, and within a reasonable time from issuance. Non-commercial, educational and scientific use of this report by governmental agencies is regarded as “fair use” and not a violation of copyright. The client and governmental agencies may make additional copies of this document for internal use. Copies may also be made available to the public as required by law. The reprint must acknowledge the copyright and indicate that permission to reprint has been received. Copyright 2007 SCS Engineers LETTER REPORT OF SOIL VAPOR SURVEY AND LIMITED HUMAN HEALTH RISK ASSESSMENT Proposed Inland Valley Medical Center Assessor’s Parcel Numbers 959-080-001, - 007, -008, -009, and -010 Temecula, California Environmental Consultants 8799 Balboa Avenue Suite 290 San Diego, CA 92123 858-571-5500 FAX 858-571-5357 www.scsengineers.com October 25, 2007 Project Number: 01207522.00 Copy No.____ Emery Papp City of Temecula 43200 Business Park Drive Temecula, CA 92590 RE: Letter Report of Soil Vapor Survey (Survey) and Limited Human Health Risk Assessment (Assessment) Hospital Site: Proposed Inland Valley Medical Center Assessor=s Parcel Numbers (APNs) 959-080-001, -007, -008, -009, and -010 Temecula, California Dear Mr. Papp: SCS Engineers is pleased to present this letter report (Report) of the soil vapor survey (Survey) at the above-referenced Hospital Site (Figures 1, 2, and 3). This Report summarizes the results of the work that was conducted to evaluate certain specific environmental conditions at the Hospital Site. Relevant portions of this Assessment were conducted in general accordance with the guidelines set forth by the California Department of Toxic Substance Control (DTSC) and in accordance with the Contract between SCS and City of Temecula (Client). BACKGROUND Based on our conversations and a review of Client-provided documents, we understand that the Hospital Site consists of approximately 26.5 acres of land in Temecula, California (Figure 1). The Hospital Site is currently undeveloped land (APNs 959-080-001, -007, -008, -009, and -010) and is proposed to be developed into facilities for the Inland Valley Medical Center. We understand that Hospital Site improvements will consist of slab-on-grade medical offices and support buildings, as well as a two-tower 320-bed hospital and related physical plant, parking and hardscape/landscape improvements. It is our understanding that below grade improvements are not currently planned. We also understand that potable water will be supplied by others and that no on-site groundwater production wells are planned. Environmental Consultants 8799 Balboa Avenue Suite 290 San Diego, CA 92123 858-571-5500 FAX 858-571-5357 www.scsengineers.com CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 2 of 21 October 25, 2007 SCS Engineers Regulatory Background Known, Reported, or Suspected Releases Within the Hospital Site Vicinity Chevron Service Station #204029, 31669 Highway 79 South, Temecula, CA The above-referenced facility is located approximately 200 feet southeast of the Hospital Site (Figures 2 and 3). The first quarter 2007 quarterly groundwater monitoring report and historical Chevron facility assessment report were reviewed and included groundwater gradient and analytical data. The facility is a service station and has six groundwater monitoring wells that are all located on the service station property. Groundwater monitoring has been on-going since at least August 2001 and methyl tertiary butyl ether (MTBE) has been detected in all the wells at some point between August 2001 and January 2007. MTBE and tertiary butyl alcohol (TBA) have been reported at maximum concentrations of 1,400 micrograms per liter (Fg/L) and 420 Fg/L, respectively. During the first quarter 2007, the groundwater gradient was reported to be to the west to northwest and groundwater was reported to range between 23.93 and 26.80 feet below ground surface (bgs). Based on the reported groundwater flow direction and groundwater sample analytical results, MTBE impacted groundwater is likely to be migrating towards the Hospital Site. The following table summarizes the recently reported concentrations of the target constituents of concern (CoCs) and depth to groundwater for each well at the service station. Please note that based on the data we have reviewed, benzene has not been detected in wells at this facility during remedial sampling activities. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 3 of 21 October 25, 2007 SCS Engineers Table 1 GROUNDWATER ANALYTICAL RESULTS SUMMARY CHEVRON SERVICE STATION #204029 Well Number Distance and Direction Depth to Groundwater (feet) TPHg (Fg/L) MTBE (Fg/L) TAME (Fg/L) ETBE (Fg/L) TBA (Fg/L) MW-1 300 ft southeast 26.08 <50 11 <2 <2 <10 MW-2 360 ft southeast 23.93 <50 <2.0 <2 <2 <10 MW-3 200 ft southeast 24.52 <50 <2.0 <2 <2 <10 MW-4 320 ft southeast 25.56 <50 <2.0 <2 <2 <10 MW-5 255 ft southeast 26.80 <50 4 <2 <2 <10 MW-6 250 ft southeast 25.78 <50 <2 <2 <2 <10 Notes: TPHg =Total petroleum hydrocarbons as gasoline. MTBE = methyl tertiary butyl ether. DIPE = di-isopropyl ether. TAME = tertiary amyl methyl ether. ETBE = ethyl tertiary butyl ether. TBA = tertiary butyl alcohol. Samples collected by Holguin, Fahan & Associates on January 24, 2007. Groundwater samples analyzed via EPA Method 8260B. Approximate distance and direction from Hospital Site. Fg/L = micrograms per liter. A report prepared by Holguin, Fahan & Associates (October 2005), provided the following information in connection with the groundwater sampling: $ The report concluded that AMTBE concentrations are consistent with the historical levels and show a general overall concentration downward trend.@ Based on a review of reports for this facility, the MTBE-bearing groundwater is interpreted to have migrated beyond the boundaries of this facility. Based on the reported gradient and the Hospital Site=s proximity to the release, it is possible that the MTBE-impacted groundwater has migrated onto the Hospital Site. However, MTBE was not detected in a groundwater sample collected from soil boring B9 (Figure 3) at the Hospital Site, downgradient from this release in January 2006. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 4 of 21 October 25, 2007 SCS Engineers Because MTBE-bearing groundwater may have migrated onto the Hospital Site, there is the potential for impacted groundwater to result in vapor phase migration and the potential for diffusion-driven flux into occupied structures. This possibility, along with the potential migration of MTBE in groundwater, is more fully explored in our current and previous Phase II testing program, which is further described in the following sections of this Report. Shell Service Station, 44260 Temecula Parkway, Temecula, CA The above-referenced facility is located approximately 840 feet east by southeast of the Hospital Site (Figures 2 and 3). In September 2001, five groundwater monitoring wells were installed at the facility to investigate possible impacts to soil and groundwater by on-site underground storage tanks (USTs). MTBE was detected in soil and groundwater samples collected during the September 2001 assessment. Additional assessment activities in 2002, 2003, and 2004 have resulted in the installation of an additional thirty-two groundwater monitoring wells at downgradient locations and the completion of thirty-five cone penetration test (CPT) locations. Groundwater samples collected from the monitoring wells have had reported concentrations of MTBE, TBA, tertiary amyl methyl ether (TAME), and ethyl tertiary butyl ether (ETBE). Quarterly groundwater monitoring and sampling has been conducted at the facility since 2001. MTBE and TBA have been reported at maximum concentrations1 of 17,000 Fg/L and 3,000 Fg/L, respectively, from groundwater samples collected from monitoring wells (MW-7A) located at the facility. Remedial action in the form of groundwater extraction was conducted between May 2002 and June 2003 using a vacuum truck, which extracted a reported 1.6 million gallons of groundwater containing dissolved-phase petroleum hydrocarbons from the facility. Between May 2003 and November 2004, three groundwater extraction wells and two groundwater injection wells were installed west of the facility as a groundwater remediation system to capture and treat petroleum hydrocarbons migrating in the groundwater from the facility. The groundwater remediation system was in use at the facility from July 2004 to August 2006. As of April 2007, the groundwater remediation system is offline pending evaluation of the rebound of the contaminants of concern. During the first quarter 2007 (January 2007) groundwater was reported to flow to the west and groundwater depth was reported to range between 25 and 28 feet bgs. The monitoring wells closest to the Hospital Site that screen what is reported as an upper groundwater zone2 are MW-22A, MW-23A, MW-24A, and MW-25A. Based on the 1 MTBE and TBA groundwater concentrations collected in September, 6, 2002, groundwater concentrations from monitoring well MW7A have not been reported above the laboratory reporting limit since October 2005. 2 Miller Brooks reports three groundwater regimes that they have investigated: upper, intermediate, and CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 5 of 21 October 25, 2007 SCS Engineers reported groundwater gradient in the shallow groundwater regime and groundwater sample analytical results, MTBE impacted groundwater is potentially migrating onto the Hospital Site. However, MTBE was not detected in a groundwater sample collected from soil boring B10 (Figure 3) at the Hospital Site, downgradient from this release in January 2006. deep. For the purposes of our fate and transport analysis, we have focused on the upper groundwater regime, due to its proximity to potential receptors and Site buildings. The following table summarizes the recently reported concentration of the target constituents, approximate distance and direction to the Hospital Site, and depth to groundwater for each well in the immediate vicinity of the Hospital Site. Table 2 GROUNDWATER ANALYTICAL RESULTS SUMMARY SHELL SERVICE STATION Well Number Distance and Direction Depth to Groundwater (feet) TPHg (Fg/L) MTBE (Fg/L) TAME (Fg/L) ETBE (Fg/L) TBA (Fg/L) MW-22A 140 feet southeast 22.72 <50 4.7 <2.0 <2.0 <10 MW-23A 130 feet south 22.46 <50 7.0 <2.0 <2.0 <10 MW-24A 10 feet south 24.00 <50 2.3 <2.0 <2.0 <10 MW-25A 90 feet southeast 24.56 <50 <1.0 <2.0 <2.0 <10 Notes: TPHg =Total petroleum hydrocarbons as gasoline. MTBE = methyl tertiary butyl ether. DIPE = di-isopropyl ether. TAME = tertiary amyl methyl ether. ETBE = ethyl tertiary butyl ether. TBA = tertiary butyl alcohol. Samples from MW-22Aand MW-23A collected on July 27, 2006, and samples from MW-24A and MW-25A collected on January 25, 2007 by Delta Environmental. Samples reportedly not collected for the last two sampling events from MW-22A and MW-23A because wells were inaccessible. Groundwater samples analyzed via EPA Method 8260B. Approximate distance and direction from Hospital Site. Wells located downgradient from Shell Station. Fg/L = micrograms per liter. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 6 of 21 October 25, 2007 SCS Engineers The groundwater monitoring report for the third quarter 2005, prepared by Miller Brooks Environmental (October 2005), concluded the following information in connection with the groundwater sampling: $ The report concluded that Agroundwater beneath and downgradient of the Shell Service Station has been impacted with petroleum hydrocarbons, specifically MTBE and TBA.@ $ AGroundwater elevation and chemical constituent data indicate that the flow direction begins to divert to the north (northwesterly) just east of the Chevron Service Station.@ $ A...results of the most recent available quarterly groundwater monitoring records at the Chevron Service Station indicate the presence of dissolved- phase petroleum hydrocarbons (MTBE) extending west and north of the Chevron Service Station beneath Highway 79.@ Additional Site Assessment- Shell Service Station In January and February 2006, Miller Brooks3 completed eleven CPT borings on the proposed Hospital Site. Forty groundwater samples were collected and reportedly analyzed for TPHg, benzene, toluene, ethylbenzene, total xylenes (BTEX), MTBE, and other fuel oxygenates. No concentrations of TPHg, benzene, ethylbenzene, TBA, TAME, ETBE, or DIPE were reported above the laboratory reporting limits. Toluene was reported at concentrations ranging from 0.53 μg/L to 1.1 μg/L. Total xylenes were reported at concentrations ranging from 1.1 μg/L to 2.22 μg/L. Fourteen of the forty samples collected were reported to contain concentrations of MTBE above the laboratory reporting limits and concentrations ranged from 1.1 μg/L to 77 μg/L. The highest reported concentration of MTBE (77 μg/L) was reported in location CPT-50, at a depth of 33 feet bgs, which is located along the north side Highway 79 South. The above-referenced assessment report, prepared by Miller Brooks (August 2005), concluded the following information in connection with the CPT sampling: $ Athere does not appear to be the discrete water-bearing zones (upper [20 feet to 26 feet bgs], intermediate [30 feet to 75 feet bgs], and deeper [deeper than 75 feet bgs]) as previously observed in CPT profiling conducted on the Vail Ranch Shopping Center and Redhawk Parkway.@ 3 Summary of Additional Site Assessment Activities, Shell Service Station (Formerly Texaco Branded), 44620 Redhawk Parkway, Temecula, California, Case Number R9-2002-0340, Miller Brooks Environmental 2005. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 7 of 21 October 25, 2007 SCS Engineers $ APPD (pore pressure dissipation) tests from these four CPTs (CPT-46, CPT- 47, CPT-49, and CPT-53) indicated that the depth to groundwater ranged from approximately 8 to 18 feet bgs, however, no groundwater was encountered at these depths during groundwater sampling activities.@ Based on the reported groundwater sample analytical data and gradient from this report, MTBE impacted groundwater has migrated onto the southern edge of the Hospital Site. Arco Service Station #5695, 44239 Margarita Parkway, Temecula, CA Arco Service Station #5695 is located approximately 240 feet east of the Hospital Site (Figure 2 and 3). Delta Environmental (Delta) collected 28 soil samples in June 2000 during a dispenser upgrade at the Arco property. The soil samples were reported to contain concentrations of total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, total xylenes, and MTBE. The soil samples were reported to contain concentrations ranges as follows: TPHg (1.1 mg/kg to 1,300 mg/kg) , benzene (1.3 mg/kg), toluene (0.012 mg/kg to 20 mg/kg), ethylbenzene (0.014 mg/kg to 47 mg/kg), total xylenes (0.029 mg/kg to 105 mg/kg), and MTBE (0.011 mg/kg to 43 mg/kg). In January 2001, Secor International Incorporated (Secor) installed three monitoring wells (MW1, MW2, and MW3) at the Arco property. Soil samples collected during the installation of the wells were reported to contain concentrations of MTBE above the laboratory reporting limit. Groundwater samples collected from three wells all were reported to contain MTBE concentrations above the laboratory reporting limits. In February 2001, Secor advanced six CPT borings (CPT-1 though CPT-6) at the facility, soil and groundwater samples were collected and tested for TPHg, BTEX, and MTBE, ETBE, TAME, TBA, and DIPE. MTBE was reported to be above the laboratory reporting limit in soil samples collected from two of the six CPT locations and was reported in groundwater samples collected from all CPT locations. TBA was also reported in one groundwater sample collected from the CPT locations. Between April 2001 through February 2003, Secor completed thirteen additional CPT borings (CPT-7 though CPT-17, CPT-18, and CPT-19) and installed eleven groundwater monitoring wells (MW4 through MW14). Groundwater samples collected from the monitoring wells MW1, MW2, MW3, MW5, MW6, MW7, MW8, and MW9 have been reported to have concentrations of MTBE above the laboratory reporting limit at some period since quarterly monitoring began at the Arco property. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 8 of 21 October 25, 2007 SCS Engineers In November 2002, a remediation system was installed which consisted of groundwater extraction pumps. Groundwater collected from the remediation system was stored in Baker tanks though June 2003, and the groundwater was disposed of off-site. In June 2003, three groundwater injection wells (IW-1, IW-2, and IW-3) were installed along Dartola Road, which abuts the eastern edge of the Hospital Site. Since the third quarter 2003, groundwater pumped from the Arco property remediation system has been treated and then reinjected into the subsurface using the three groundwater injection wells. As of the first quarter 2007, the Arco Service Station has a monitoring well network consisting of thirteen groundwater monitoring wells. Three additional groundwater monitoring wells (MW-10S-A, MW-10S-B, and MW-10D) were destroyed in December 2006 to accommodate construction on the property to the north. Groundwater monitoring has been on-going since February 2001, and MTBE has been detected up tp concentrations of 1,900 Fg/L (MW-6)4. During the first quarter 2007 groundwater5 was reported to flow to the west-northwest and groundwater was reported to range between 25.83 and 27.83 feet bgs in the shallow aquifer zone. Based on the reported groundwater flow direction and groundwater sample analytical results, MTBE impacted groundwater is likely to be migrating towards the Hospital Site as a result of this release. However, MTBE was not detected in a groundwater sample collected from soil boring B10 (Figure 3) at the Hospital Site, downgradient from this release in January 2006. The following table summarizes the recently reported concentration of the target constituents, approximate distance and direction to the Hospital Site, and depth to groundwater for each well in the immediate vicinity of the Hospital Site. 4 During the most current sampling of April 2007, MTBE was reported at a concentration of 5.1 Fg/L in MW-6, which is below the MCL for drinking water. 5 Atlantic Richfield Company Quarterly Report First Quarter 2007, Arco Service Station #5695, 44239 Margarita Parkway, Temecula, CA, Secor International Incorportated, 2007 CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 9 of 21 October 25, 2007 SCS Engineers Table 3 GROUNDWATER ANALYTICAL RESULTS SUMMARY ARCO #5695 SERVICE STATION Well Number Distance and Direction Depth to Groundwater (feet) TPHg (Fg/L) MTBE (Fg/L) TAME (Fg/L) ETBE (Fg/L) TBA (Fg/L) MW-1 305 feet east 27.17 <50 16 <2.0 <2.0 25 MW-2 325 feet east 26.02 <50 1.6 <5.0 <5.0 <25 MW-3 330 feet east 26.38 280 1.9 <5.0 <5.0 <25 MW-4 340 feet east 26.13 <50 3.3 <5.0 <5.0 <25 MW-5 350 feet east 27.70 <50 <1.0 <5.0 <5.0 <25 MW-6 315 feet east 27.83 <50 2.2 <5.0 <5.0 <25 MW-7 370 feet east 27.32 <50 19 <5.0 <5.0 <25 MW-8 270 feet east 27.75 <50 0.75J <5.0 <5.0 <25 MW-9 225 feet east 26.90 <50 6.3 <5.0 <5.0 <25 MW-11 340 feet east 46.93 <50 <1.0 <5.0 <5.0 <25 MW-12 230 feet east 45.93 <50 <1.0 <5.0 <5.0 <25 MW-13 250 feet east 25.53 <50 <1.0 <5.0 <5.0 <25 MW-14 200 feet east 26.91 <0.32 <50 <1.0 <5.0 <5.0 Notes: TPHg =Total petroleum hydrocarbons as gasoline. MTBE = methyl tertiary butyl ether. DIPE = di-isopropyl ether. TAME = tertiary amyl methyl ether. ETBE = ethyl tertiary butyl ether. TBA = tertiary butyl alcohol. Samples collected by Delta Environmental on January 31, 2007. Groundwater samples analyzed via EPA Method 8260B. Approximate distance and direction from Hospital Site. Fg/L = micrograms per liter. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 10 of 21 October 25, 2007 SCS Engineers Previous SCS Environmental Investigations Soil Vapor Survey In January 2006, a soil vapor survey was performed in order to assess the possible presence and concentration of BTEX and MTBE in the shallow subsurface soil vapor in the vicinity of the footprint of the proposed buildings at the Hospital Site. Soil vapor samples were collected from 7 locations within the footprint of the proposed Hospital Site buildings (SV1 through SV6, and SV8). Three additional locations (SV7, SV9, and SV10) were located at locations in the southwest portion of the Hospital Site in an attempt to intercept the offsite MTBE groundwater plume that was thought to have been intruding onto the Hospital Site. Samples collected from SV1 through SV10 were reported to have no detectable concentrations of BTEX or MTBE above laboratory detection limits.6 The locations of the soil vapor samples are shown in Figure 2. Groundwater Sampling In July 2006, SCS personnel mobilized to the Hospital Site and advanced ten groundwater sampling locations in vicinity of the proposed Hospital Site buildings and at locations designed to intercept the possible on-site migration of MTBE from known off-site sources. The locations of the soil borings where co-located with the soil vapor sampling locations in the vicinity of the footprint of the proposed buildings at the Hospital Site buildings (B1 through B6, and B8). Locations B7, B9, and B10 were drilled in locations in the southwest portion of the Hospital Site in an attempt to intercept the offsite MTBE groundwater plume that may be intruding onto the Hospital Site. The groundwater samples from each boring were collected using a Hydropunch7 sampler. The sampler was driven into the first encountered water- bearing zone and an in-situ groundwater sample was collected and placed in a laboratory-supplied container provided by H&P. Groundwater samples collected were submitted to a on-site state-accredited mobile laboratory, and were analyzed in general accordance with EPA Method 8260B for BTEX and MTBE. The locations of the groundwater samples are shown in Figure 3 and the analytical results are summarized in the following table. 6 The laboratory detection limit for benzene, toluene, ethylbenzene, and MTBE is 1.0 micrograms per liter (Fg/L). The laboratory detection limit for total xylenes is 3.0 Fg/L CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 11 of 21 October 25, 2007 SCS Engineers Table 4 Groundwater Sample Analytical Results Sample Number Benzene (Fg/L) Toluene (Fg/L) Ethyl- Benzene (Fg/L) Total Xylenes (Fg/L) MTBE (Fg/L) B1 <0.5 <0.5 <0.5 <1.5 <1.0 B2 <0.5 <0.5 <0.5 <1.5 <1.0 B3 <0.5 <0.5 <0.5 <1.5 <1.0 B4 <0.5 <0.5 <0.5 <1.5 <1.0 B5 <0.5 <0.5 <0.5 <1.5 1.3 B6 <0.5 <0.5 <0.5 <1.5 <1.0 B7 <0.5 <0.5 <0.5 <1.5 <1.0 B8 <0.5 <0.5 <0.5 <1.5 <1.0 B9 <0.5 <0.5 <0.5 <1.5 <1.0 B10 <0.5 <0.5 <0.5 <1.5 <1.0 Notes: Samples collected by Environmental Business Solutions on January 3, 2005. <1 = Not reported at concentrations greater than the indicated detection limit. BTEX = Benzene, toluene, ethylbenzene, and total xylenes. MTBE = Methyl tertiary butyl ether. BTEX and MTBE analyzed in general accordance with EPA Method 8260B. Fg/L = micrograms per liter. Previous assessment work performed at the Hospital Site by SCS and the current scope of services at the Hospital Site has been designed to assist in the ongoing California Environmental Quality Act (CEQA) review process for the future development at the Hospital Site. This Report describes Assessment activities which were conducted at the Hospital Site in July 2007 to evaluate certain specific environmental conditions in the shallow subsurface soil vapor in the vicinity of the footprint of the proposed buildings at the Hospital Site. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 12 of 21 October 25, 2007 SCS Engineers OBJECTIVES The objectives of the scope of services described in this Report were to: C Assess the extent and concentration of volatile organic compounds (VOCs) including MTBE in soil vapor in selected locations of the Hospital Site. C Assess the likelihood of a (Significant7) human health risk in association with detected VOCs and MTBE due to the upward migration of soil vapors containing elevated concentrations of petroleum hydrocarbons. SCOPE OF SERVICES Preparation for Field Work Hospital Site Health and Safety Plan A Hospital Site health and safety plan (Plan) was required for the work conducted at the Hospital Site by workers within the Aexclusion zone@ pursuant to the regulations in 29 Code of Federal Regulations (CFR) Part 1910.120 and Title 8 California Code of Regulations (CCR) Section 5192. A Plan was prepared which outlined the potential chemical and physical hazards that might have been encountered during the drilling and sampling activities. The appropriate personal protective equipment and emergency response procedures for the Hospital Site-specific chemical and physical hazards were detailed in this Plan. All field personnel involved with the field work were required to read and sign the document in order to encourage proper health and safety practices. Utility Search and Markout Prior to drilling, SCS contacted Underground Service Alert (USA) to minimize the likelihood of drilling into an underground utility. USA notified SBC, Rancho California Water District, and the City of Temecula Water, Sewer, and Traffic Departments. Project Management, Subcontractor Management, and Scheduling Prior to mobilizing for field work, SCS notified the Client and scheduled the subcontractors including the laboratory and the drilling company. 7 The criterion used in this analysis is one in a million (1.0 E-6) excess lifetime cancer risk (ECR). A high likelihood of risk above this threshold is defined as Asignificant.@ For the purposes of this limited HRA, a commercial land use, consistent with the Site=s current zoning, is assumed. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 13 of 21 October 25, 2007 SCS Engineers Field Activities Soil Vapor Survey Soil Vapor Sampling Procedures On July 16 and 18, 2007, a soil vapor survey was performed in order to assess the possible presence and concentration of VOCs and MTBE in the shallow subsurface soil vapor in the vicinity of the footprint of the proposed buildings at the Hospital Site. The soil vapor samples were collected from two depths from 11 locations within the footprint of the proposed Hospital Site buildings (SG1 through SG11). The location placement, and density of soil vapor sampling locations was designed to be representative of soil conditions beneath the Hospital Site buildings and in general accordance with DTSC guidance8. Additional Soil vapor samples were collected on August 21 and 24, 2007. Locations SG12, SG13, and SG14 were located at locations in the southwest portion of the Hospital Site in an attempt to intercept the offsite MTBE groundwater plume that may be intruding onto the Hospital Site. The locations of the soil vapor samples are shown in Figure 2. Prior to collecting a soil vapor sample, an approximately 1-inch diameter hole was drilled in the ground. The soil vapor sampling probe, which consists of a 1-inch diameter, hollow metal rod was then manually driven to the desired sampling depth with a hammer. Once reaching the desired depth, a soil vapor well was constructed using a vapor probe implant, sand pack, and bentonite seal. The soil vapor implant was connected to the surface and a sampling port using dedicated Nylaflow tubing. Soil vapor samples were collected from sample points placed at depths of approximately 5 and 15 feet bgs, by a technician provided by H & P Mobile Geochemistry (H&P), under the direct supervision of an SCS environmental professional. The soil vapor samples were collected in general accordance with the State of California Department of Toxic Substance Control (DTSC) guidelines (Dated February 7, 2005). The soil vapor samples were immediately transferred to a state-accredited on-site mobile laboratory provided by H&P for analysis for VOCs in general accordance with EPA Method 8260B. The results of this analysis are summarized in Table 5, and the laboratory reports, chain of custody documentation and standard operating 8 Interim Final Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air, Department of Toxic Substances Control, California Environmental Protection Agency, December 15, 2004 (Revised February 7, 2005) CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 14 of 21 October 25, 2007 SCS Engineers procedures for soil vapor sample collection are presented in the Appendix. Chain-of- custody procedures were implemented for sample tracking. A written analytical report was provided by the laboratory upon the completion of the sample testing. Soil vapor samples were collected on two days to assess possible temporal variability of soil vapor concentrations. As appropriate, soil vapor drilling equipment was cleaned or changed out between soil vapor probes to minimize the likelihood of cross-contamination of the soil vapor probe holes and to minimize the potential for a false positive in the soil vapor samples analyzed. Hospital Site Safety The following procedures were used to conduct the drilling activity in a safe manner: C Procedures stated in the Hospital Site Health and Safety Plan were followed. C Unauthorized personnel were not permitted to enter the exclusion zone. Laboratory Analysis The soil vapor samples were analyzed for VOCs in general accordance with EPA Method 8260B. A written analytical report was provided upon completion of the sample testing and is included in the Appendix. FINDINGS Laboratory Analytical Results Soil Vapor Survey Results The laboratory analytical data for the soil vapor samples are presented in Table 5 and on Figure 2, and the laboratory report is included in the Appendix. Samples collected from SG1 through SG14 were reported to have no detectable concentrations of VOCs or MTBE above laboratory detection limits.9 9 The laboratory detection limit for benzene, toluene, ethylbenzene, and MTBE is 1.0 micrograms per liter (Fg/L). The laboratory detection limit for total xylenes is 3.0 Fg/L CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 15 of 21 October 25, 2007 SCS Engineers Table 5 2007 Soil Vapor Sample Analytical Results Sample Number Sample Depth (feet below grade) Benzene (Fg/L) Toluene (Fg/L) Ethyl- Benzene (Fg/L) Total Xylenes (Fg/L) MTBE (Fg/L) Other VOCs 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG1 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG2 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG3 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG4 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG5 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG6 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG7 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG8 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG9 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG10 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG11 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG12 15 <0.1 <1.0 <1.0 <3 <1.0 ND CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 16 of 21 October 25, 2007 SCS Engineers Sample Number Sample Depth (feet below grade) Benzene (Fg/L) Toluene (Fg/L) Ethyl- Benzene (Fg/L) Total Xylenes (Fg/L) MTBE (Fg/L) Other VOCs 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG13 15 <0.1 <1.0 <1.0 <3 <1.0 ND 5 <0.1 <1.0 <1.0 <3 <1.0 ND SG14 15 <0.1 <1.0 <1.0 <3 <1.0 ND Notes: Samples SG1 through SG11 collected by SCS Engineers on July 16 and 18, 2007. Samples SG12, SG13, and collected by SCS Engineers on August 21 and 24, 2007. Fg/L = micrograms per liter. <1 = Not reported at concentrations greater than the indicated reporting limit. ND = Not report at concentrations greater than the laboratory reporting limit. BTEX = Benzene, toluene, ethylbenzene, and total xylenes. MTBE = Methyl tertiary butyl ether. BTEX and MTBE analyzed in general accordance with EPA Method 8260B. Limited Human Health Risk Assessment No detectable concentrations of the target analytes (VOCs or MTBE) were reported in soil vapor beneath the proposed Hospital Site buildings footprints (Table 5 and Figure 2). Because no VOCs or MTBE were detected, it is our opinion that there is a low likelihood of exposure to benzene or MTBE resulting from soil vapor migration and flux and a very low likelihood of related Significant human health risk. Hypothetical Health Risk Scenarios In the order to better understand the hypothetical risk of MTBE-bearing groundwater migrating from off-site sources onto the Hospital Site and under the proposed buildings, several scenarios were evaluated based on data collected from the groundwater monitoring well networks associated with the gas stations in the Hospital Site Vicinity. All scenarios were modeled using the DTSC=s Screening-Level Model for Groundwater Contamination, last modified January 21, 2005, which is based on the Johnson-Ettinger (JE) vapor intrusion model. The default values were used for most parameters to be conservative. The following assumptions were used to estimate health risk: $ The MTBE concentrations in groundwater were conservatively assumed to occur uniformly across the Hospital Site. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 17 of 21 October 25, 2007 SCS Engineers $ A residential adult exposure scenario was used in which the adult worker weighs 70 kilograms, and works at the Hospital Site for 350 days a year per year for 30 years. Please note, the DTSC model incorporates a 24-hour exposure period and thus the realistic exposure period is overestimated by at least a factor of two. $ The calculations used in the health risk analysis use standard (DTSC defaults for soil type) physical parameters to describe soil conditions (37 percent total porosity and a dry bulk density of 1.66 grams per cubic centimeters). $ The DTSC default soil gas advection rate (flow rate) of 5 liters per minute for every 100 square meters of floor area was used. The soil advection rate was estimated for the tower building (approximately 16,555 sq. meters) and the proposed cancer center building (approximately 743 sq. meters) to be approximately 827 liters per minute (L/m) for the tower building and 37 L/m for the cancer center building. $ Both carcinogenic and noncarcinogenic health risks were estimated. Of the VOCs reported in the groundwater, only MTBE is considered a potential carcinogen. $ The calculations used depth to groundwater of 26 feet bgs across the Hospital Site, which we believe is reasonable based on a review of groundwater data in the Hospital Site vicinity. Scenario 1 AMTBE-bearing groundwater has migrated onto the Hospital Site from the southeast@. There are four monitoring wells along the southern edge of the proposed hospital property that screen the shallow groundwater (MW-24A, MW26A, MW-27A, and MW-28A). Monitoring well MW-28A is located along the southern border of the proposed hospital Hospital Site, at the approximate mid-point of the southern Hospital Site boundary, and has had the highest reported concentration of MTBE out of the four wells. The highest reported concentration of MTBE in this well has been 97 Fg/L in July 2006 which subsequently decreased to 55 Fg/L in April 2007. Using the maximum concentration reported in this well (97 Fg/L) and assuming a conservative residential use risk scenario (350 days a year for 30 years exposure scenario), the DTSC model indicated less than significant cancer risks of 1.1E-07. These cancer risks are almost one order of magnitude below the typical risk threshold CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 18 of 21 October 25, 2007 SCS Engineers of 1E-06 (one in a million). The risk of non-cancer health effects is also less then significant based on a Hazard Index of 3.2E-04, well below the typical risk threshold of 1. Scenario 2 AMTBE-bearing groundwater has migrated onto the Hospital Site from the east@. Monitoring well MW-14 is upgradient from the hospital property, located approximately 470 feet east of the proposed cancer center in the eastern portion of the property along Dartolo Road. This is the closest well to the Hospital Site associated with the Arco Service Station monitoring well network. In April 2007, the concentration of MTBE in MW-14 was reported to be 1.3 Fg/L, which is the highest reported concentration since the installation of this well. Assuming the same conservative residential use risk scenario (350 days a year for 30 years exposure scenario) as Scenario 1, the DTSC model indicated less than significant cancer risks of 1.4E-09. These cancer risks are almost two orders of magnitude below the less than significant risk threshold of 1E-06 (one in a million). The risk of non-cancer health effects is also less than significant based on a Hazard Index of 4.2E-06, well below the typical risk threshold of 1. The Excel spreadsheets for the risk calculations associated with MTBE (obtained from the DTSC website) are presented in the Appendix. Discussion Based on the review of the ongoing groundwater assessment work being conducted by others in the Hospital Site vicinity, MTBE-bearing groundwater may have migrated onto the Hospital Site along southern boundary. Based on the previous and current soil vapor sampling, it has interpreted that there is a very low likelihood of related Significant human health risk at Hospital Site because of the possible presence MTBE-bearing groundwater beneath the Hospital Site. As mentioned above, MTBE-bearing groundwater may have migrated onto the Hospital Site along southern boundary. However, to address the concern that MTBE in groundwater may pose a health risk via vapor intrusion into the hospital in the event that MTBE does migrate on-site from the east (Arco Service Station) or from the southeast (Chevron and Shell Service Stations) under the future hospital buildings several scenarios, based on highest reported actual MTBE concentrations near the Hospital Site were modeled to better understand the hypothetical risk. Concentrations of MTBE in the monitoring wells MW-24A, MW-25A, MW26A, MW-27A, MW-28A, and MW-14 (closest monitoring wells to the Hospital Site) have CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 19 of 21 October 25, 2007 SCS Engineers been decreasing or are below the MCLs for drinking water, making these scenarios even more conservative than current conditions at the property. Based on the modeling for these scenarios the concentrations of MTBE in groundwater would have to increase by one to two orders of magnitude to before the model predicts there is even the potential for a significant health risk. Additionally, MTBE has been phased-out as a fuel additive in the State of California. Since MTBE is no longer used in gasoline fuel distributed in California, it is unlikely that additional releases of MTBE will occur from the USTs in the Hospital Site vicinity. With the reduction of the MTBE sources in the Hospital Site vicinity along with ongoing remediation activities at the three USTs sites in the vicinity, MTBE concentrations in groundwater will likely continue to decrease, this hypothesis is corroborated by the decreasing concentration trend exhibited in the monitoring wells adjacent to the Hospital Site (MW-24A, MW-25A, MW26A, MW-27A, MW-28A, and MW-14 ). However, to the extent the Hospital Site is developed, the developer may need to manage or incur costs associated with the presence of petroleum hydrocarbons in the soil or groundwater beneath the Hospital Site (e.g., if deep foundation or footings penetrate impacted soil or groundwater, or if dewatering is required). Depending on Hospital Site development plans, you may need to retain a qualified environmental professional during grading and foundation work to conduct field screening for petroleum hydrocarbons. We recommend that when construction plans are finalized that they be reviewed by an environmental professional to assess the necessity of further involvement and oversight. CONCLUSIONS Based on the data obtained and reviewed as part of this investigation, laboratory results, and current regulatory guidelines, it is our professional opinion that: C Volatile organic compounds (VOCs), and methyl tertiary butyl ether (MTBE) were not reported to be present at detectable concentrations in the eleven multi-depth soil vapor sampling probes beneath the footprint of the proposed Hospital Site buildings across three sampling events. C Because no VOCs or MTBE were detected, it is our opinion that there is a low likelihood of exposure to benzene or MTBE resulting from soil vapor migration and flux and a very low likelihood of related Significant human health risk. CITY OF TEMECULA Soil Vapor Survey Project Number: 01207522.00 Page 21 of 21 October 25, 2007 SCS Engineers REPORT USAGE AND FUTURE HOSPITAL SITE CONDITIONS This Report is intended for the sole usage of the Client and the parties designated by SCS. Use of this Report is subject to the provisions of the fully executed Contract between the Client and SCS. Any third party usage of this Report shall be subject to the provisions of the Contract and any unauthorized misuse of or reliance upon the Report shall be without risk or liability to SCS. The conclusions of this Report are judged to be relevant at the time the work described in this Report was conducted. Future conditions may differ and this Report should not be relied upon to represent future Hospital Site conditions unless a qualified consultant familiar with the practice of Phase II environmental assessments in Riverside County is consulted to assess the necessity of updating this Report. Although this Assessment has attempted to assess the likelihood that the Hospital Site has been impacted by a hazardous material/waste release, potential sources of impact may have escaped detection for reasons which include, but are not limited to: 1) our reliance on inadequate or inaccurate information rightfully provided to us by third parties, such as public agencies and other outside sources; 2) the limited scope of this Assessment; and 3) the presence of undetected, unknown, or unreported environmental releases. LIKELIHOOD STATEMENTS Statements of Alikelihood@ have been made in this report. Likelihood statements are based on professional judgments of SCS. The term Alikelihood,@ as used herein, pertains to the probability of a match between the prediction for an event and its actual occurrence. The likelihood statement assigns a measure for a Adegree of belief@ for the match between the prediction for the event and the actual occurrence of the event. The likelihood statements in this Report are made qualitatively (expressed in words). The qualitative terms can be approximately related to quantitative percentages. The term Alow likelihood@ is used by SCS to approximate a percentage range of 10 to 20 percent; the term Amoderate likelihood@ refers to an approximate percentage range of 40 to 60 percent; and the term Ahigh likelihood@ refers to an approximate percentage range of 80 to 90 percent. FIGURES Disclaimer: This figure is based on available data. Actualconditions may differ. All locations and dimensions are approximate. 4-WAY SITE LOCATION MAP City of Temcula State Highway Route 79 South Temecula, California Reference: U.S.G.S. 7.5 Minute Quadrangle map Pechanga, California - 1977. Photo revised 1982. Reference: U.S.G.S. 7.5 Minute Quadrangle map Pechanga, California - 1977. Photo revised 1982. North Reference: Terra Server Aerial Photograph Temecula, California - May 2002 REGIONAL SITE LOCATION 2-DIMENSIONAL SITE LOCATION 3-DIMENSIONAL SITE LOCATIONSITE AERIAL PHOTOGRAPH North (Not to scale) North (Not to scale) North SANTA YSABEL NorthIslandNAS Sa n D i ego Bay MissionBay BONSALL LAKESIDE SAN DIEGO EL CAJON LA MESA FALLBROOK PALA ESCONDIDO SANTEE ALPINE CARLSBAD LEUCADIA ENCINITAS DEL MAR LA JOLLA SOLANA BEACH CARDIFF-BY-THE-SEA TECATE VISTA SAN MARCOS JULIAN DEHESA Camp Pendleton(U.S.M.C.) FallbrookNaval WeaponsStation MCAS Miramar Forest Cleveland National Forest Anza-BorregoDesert Anza-BorregoDesert TIJUANA Calif ornia Mexico Lake Henshaw Lake Sutherland LakeHodges El Capitan Lake Loveland Reservoir CorteMadero Lake Barrett Lake Lake Morena LakeMurray L o w e rO t a yL a k e SweetwaterReservoir Lake Jennings San VicenteLake LakeWohlford LakePoway DixonLake Cleveland National JACUMBA CAMPO VALLEY CENTEROCEANSIDE RAMONA PINEVALLEY MISSION BEACH PACIFIC BEACH OCEAN BEACH CORONADO IMPERIAL BEACH BORREGO SPRINGS WARNER SPRINGS 94 67 54 54 94 78 7878 76 79 POWAY 79 CuyamacaRanchoStatePark LEMON GROVE JAMUL ToLos Angeles ToPalm Springs To San Bernardinoand Las Vegas 79 371 DESCANSO SPRINGVALLEY TEMECULA S.D. Int'lAirport(Lindbergh Field) Brown FieldMun. Airport PalomarAirport OceansideMun. Airport MontgomeryField Airport SAN YSIDRO ToIndio ToEl Centro ToEl Centro 8 8 5 5 56 76 78 1 5 805 15 15 15 15 125 163 905 BalboaPark P A CIF I C O C E A N 5 805 NATIONALCITY Riverside County San Diego County Im p e r i a l C o u n t y Sa n D i e g o C o u n t y Orange County 5 94 94 52 CHULAVISTA Figure 1 Project No.: 01207522.00 Date Drafted: 7/23/07 OTAY MESA BONITA 0 315 630 945 Approximate Graphic Scale in Feet 0 1,000 2,000 3,000 Approximate Graphic Scale in Feet SCS ENGINEERS Environmental Consultants 8799 Balboa Avenue, Suite 290 San Diego, California 92123 Project Site Project Site Project Site Project Site Disclaimer: This figure is based on available data. Actual conditions may differ. All locations and dimensions are approximate. EX P L A N A T I O N So i l v a p o r s a m p l e l o c a t i o n . So i l v a p o r s a m p l e a n a l y z e d f o r vo l a t i l e o r g a n i c c o m p u n d s ( V O C s ) i n c l u d i n g be n z e n e , t o l u e n e , e t h y l b e n z e n e , t o t a l xy l e n e s ( B T E X ) , a n d M T B E i n g e n e r a l ac c o r d a n c e w i t h E P A M e t h o d 8 2 6 0 B . Re s u l t s r e p o r t e d i n m i c r o g r a m s p e r lit e r o f v a p o r ( µ g / L v ) . N D = n o t d e t e c t e d a b o v e th e l a b o r a t o r y r e p o r t i n g l i m i t ( 1 µ g / L v ) . S a m p l e s SV 1 t h r o u g h S V 1 0 c o l l e c t e d i n J a n u a r y 2 0 0 6 , sa m p l e s S G 1 t h r o u g h S G 1 1 c o l l e c t e d i n Ju l y 2 0 0 7 , a n d s a m p l e s S G 1 2 , S G 1 3 , a n d S G 1 4 co l l e c t e d i n A u g u s t 2 0 0 7 . A l l s a m p l e s c o l l e c t e d un d e r t h e s u p e r v i s i o n o f S C S E n g i n e e r s . North CU R R E N T A N D P R E V I O U S S O I L V A P O R SA M P L I N G L O C A T I O N S W I T H AN A L Y T I C A L R E S U L T S Ci t y o f T e m e c u l a St a t e H i g h w a y R o u t e 7 9 Te m e c u l a , C a l i f o r n i a Figure 2Project No.:01207522.00 Date Drafted:8/28/07 Re p o r t e d g r o u n d w a t e r g r a d i e n t , a s r e p o r t e d b y De l t a E n v i r o n m e n t a l ( S h e l l [ J a n 2 0 0 7 ] ) , Ho l g u i n , F a h a n , & A s s o c i a t e s ( C h e v r o n [ J a n 2 0 0 7 ] ) , an d D e l t a E n v i r o n m e n t a l ( A R C O [ J a n 2 0 0 7 ] ) . S C S E N G I N E E R S En v i r o n m e n t a l C o n s u l t a n t s 87 9 9 B a l b o a A v e n u e , S u i t e 2 9 0 Sa n D i e g o , C a l i f o r n i a 9 2 1 2 3 SG 3 De p t h VO C s 5 ND MT B E ND 15 ND ND 0 1 2 5 2 5 0 3 7 5 Ap p r o x i m a t e G r a p h i c S c a l e i n F e e t H i g h w a y 7 9 S o u t h D a r t o l o R d Margarita R d Ar c o Shell Ch e v r o n County G l e n W a y Fl o o d C o n t r o l Ch a n n e l SV 9 De p t h BT E X 5 ND MT B E ND Da t e 1/ 3 / 0 5 SV 1 0 De p t h BT E X 5 ND MT B E ND Da t e 1/ 3 / 0 5 SV 7 De p t h BT E X 5 ND MT B E ND Da t e 1/ 3 / 0 5 SV 3 De p t h BT E X 5 ND MT B E ND Da t e 1/ 3 / 0 5 SV 8 De p t h BT E X 5 ND MT B E ND Da t e 1/ 3 / 0 5 SV 6 De p t h BT E X 5 ND MT B E ND Da t e 1/3 / 0 5 SV 5 De p t h BT E X 5 ND MT B E ND Da t e 1/ 3 / 0 5 SV 2 De p t h BT E X 5 ND MT B E ND Da t e 1/3 / 0 5 SV 1 De p t h BT E X 5 ND MT B E ND Da t e 1/ 3 / 0 5 SV 4 De p t h BT E X 5 ND MT B E ND Da t e 1/ 3 / 0 5 SG 1 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/ 1 6 / 0 7 7/ 1 8 / 0 7 SG 2 De p t h VO C s 5,1 5 ND MT B E ND 5,1 5 ND ND Da t e 7/ 1 6 / 0 7 7/ 1 8 / 0 7 SG 3 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/ 1 6 / 0 7 7/ 1 8 / 0 7 SG 5 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/1 6 / 0 7 7/1 8 / 0 7 SG 6 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/1 6 / 0 7 7/1 8 / 0 7 SG 8 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/ 1 6 / 0 7 7/ 1 8 / 0 7 SG 9 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/1 6 / 0 7 7/ 1 8 / 0 7 SG 1 1 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/1 6 / 0 7 7/1 8 / 0 7 SG 1 0 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/ 1 6 / 0 7 7/ 1 8 / 0 7 SG 4 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/1 6 / 0 7 7/1 8 / 0 7 SG 7 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 7/1 6 / 0 7 7/1 8 / 0 7 SG 1 2 De p t h VO C s 5, 1 5 ND MT B E ND 5, 1 5 ND ND Da t e 8/2 1 / 0 7 8/2 4 / 0 7 SG 1 3 De p t h VO C s 5,1 5 ND MT B E ND 5,1 5 ND ND Da t e 8/ 2 1 / 0 7 8/ 2 4 / 0 7 SG 1 2 De p t h VO C s 5,1 5 ND MT B E ND 5, 1 5 ND ND Da t e 8/ 2 1 / 0 7 8/ 2 4 / 0 7 Disclaimer: This figure is based on available data.Actual conditions may differ. All locations and dimensions are approximate. EX P L A N A T I O N Gr o u n d w a t e r s a m p l e l o c a t i o n . Gr o u n d w a t e r s a m p l e a n a l y z e d f o r b e n z e n e , to l u e n e , e t h y l b e n z e n e , t o t a l x y l e n e s ( B T E X ) , an d M T B E i n g e n e r a l a c c o r d a n c e w i t h E P A Me t h o d 8 2 6 0 B . R e s u l t s a r e r e p o r t e d i n mic r o g r a m s p e r l i t e r ( μ g / L ) . G r o u n d w a t e r s a m p l e s co l l e c t e d b y S C S E n g i n e e r s i n J a n u a r y 2 0 0 5 . North GR O U N D W A T E R S A M P L I N G L O C A T I O N S WI T H A N A L Y T I C A L R E S U L T S Ci t y o f T e m e c u l a St a t e H i g h w a y R o u t e 7 9 Te m e c u l a , C a l i f o r n i a Figure 3Project No.:01207522.00 Date Drafted:7/25/07 Re p o r t e d g r o u n d w a t e r g r a d i e n t , a s r e p o r t e d b y De l t a E n v i r o n m e n t a l ( S h e l l [ J a n 2 0 0 7 ] ) , Ho l g u i n , F a h a n , & A s s o c i a t e s ( C h e v r o n [ J a n 2 0 0 7 ] ) , an d D e l t a E n v i r o n m e n t a l ( A R C O [ J a n 2 0 0 7 ] ) . SC S E N G I N E E R S En v i r o n m e n t a l C o n s u l t a n t s 87 9 9 B a l b o a A v e n u e , S u i t e 2 9 0 Sa n D i e g o , C a l i f o r n i a 9 2 1 2 3 0 1 2 5 2 5 0 3 7 5 Ap p r o x i m a t e G r a p h i c S c a l e i n F e e t B1 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 B2 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 B3 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 B6 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 B7 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 B4 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 B8 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 B1 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 B5 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 1. 3 B9 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 B1 0 B T E X MT B E <0 . 5 <0 . 5 <0 . 5 <1 . 5 <1 . 0 H i g h w a y 7 9 S o u t h D a r t o l o R d Margarita R d Flood contr o l c h a n n e l Ar c o Shell Ch e v r o n County G l e n W a y APPENDIX ANALYTICAL DATA AND CHAIN-OF-CUSTODY DOCUMENTATION Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Sample ID Laboratory ID Matrix Date Sampled ANALYTICAL REPORT FOR SAMPLES Date Received SG14-15, P51cc E708112-01 Vapor 24-Aug-07 24-Aug-07 SG14-5, P21cc E708112-02 Vapor 24-Aug-07 24-Aug-07 SG14-5DUP, P21cc E708112-03 Vapor 24-Aug-07 24-Aug-07 SG13-15, P51cc E708112-04 Vapor 24-Aug-07 24-Aug-07 SG13-5, P21cc E708112-05 Vapor 24-Aug-07 24-Aug-07 SG12-15, P51cc E708112-06 Vapor 24-Aug-07 24-Aug-07 SG12-5, P21cc E708112-07 Vapor 24-Aug-07 24-Aug-07 Page 1 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG14-15, P51cc (E708112-01) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"101 %75-125Surrogate: Dibromofluoromethane """"110 %75-125Surrogate: 1,2-Dichloroethane-d4 """"105 %75-125Surrogate: Toluene-d8 """"107 %75-125Surrogate: 4-Bromofluorobenzene Page 2 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG14-5, P21cc (E708112-02) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"107 %75-125Surrogate: Dibromofluoromethane """"106 %75-125Surrogate: 1,2-Dichloroethane-d4 """"103 %75-125Surrogate: Toluene-d8 """"102 %75-125Surrogate: 4-Bromofluorobenzene Page 3 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG14-5DUP, P21cc (E708112-03) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"113 %75-125Surrogate: Dibromofluoromethane """"113 %75-125Surrogate: 1,2-Dichloroethane-d4 """"102 %75-125Surrogate: Toluene-d8 """"109 %75-125Surrogate: 4-Bromofluorobenzene Page 4 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG13-15, P51cc (E708112-04) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"111 %75-125Surrogate: Dibromofluoromethane """"114 %75-125Surrogate: 1,2-Dichloroethane-d4 """"104 %75-125Surrogate: Toluene-d8 """"106 %75-125Surrogate: 4-Bromofluorobenzene Page 5 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG13-5, P21cc (E708112-05) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"109 %75-125Surrogate: Dibromofluoromethane """"116 %75-125Surrogate: 1,2-Dichloroethane-d4 """"108 %75-125Surrogate: Toluene-d8 """"112 %75-125Surrogate: 4-Bromofluorobenzene Page 6 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG12-15, P51cc (E708112-06) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"105 %75-125Surrogate: Dibromofluoromethane """"115 %75-125Surrogate: 1,2-Dichloroethane-d4 """"102 %75-125Surrogate: Toluene-d8 """"99.6 %75-125Surrogate: 4-Bromofluorobenzene Page 7 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG12-5, P21cc (E708112-07) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"111 %75-125Surrogate: Dibromofluoromethane """"109 %75-125Surrogate: 1,2-Dichloroethane-d4 """"108 %75-125Surrogate: Toluene-d8 """"102 %75-125Surrogate: 4-Bromofluorobenzene Page 8 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Result Limit Reporting Units Level Spike Result Source %REC %REC Limits RPD RPD Limit Notes Analyte Volatile Organic Compounds by EPA Method 8260B - Quality Control H&P Mobile Geochemistry Batch EH72403 - EPA 5030 Blank (EH72403-BLK1)Prepared & Analyzed: 24-Aug-07 1,1-Difluoroethane (LCC)ug/l10ND Dichlorodifluoromethane "1.0ND Vinyl chloride "1.0ND Chloroethane "1.0ND Trichlorofluoromethane "1.0ND 1,1-Dichloroethene "1.0ND Methylene chloride "1.0ND Freon 113 "1.0ND trans-1,2-Dichloroethene "1.0ND 1,1-Dichloroethane "1.0ND cis-1,2-Dichloroethene "1.0ND Chloroform "1.0ND 1,1,1-Trichloroethane "1.0ND Carbon tetrachloride "1.0ND 1,2-Dichloroethane "1.0ND Benzene "1.0ND Trichloroethene "1.0ND Toluene "1.0ND 1,1,2-Trichloroethane "1.0ND Tetrachloroethene "1.0ND Ethylbenzene "1.0ND 1,1,1,2-Tetrachloroethane "1.0ND m,p-Xylene "2.0ND o-Xylene "1.0ND 1,1,2,2-Tetrachloroethane "1.0ND Methyl tert-butyl ether "1.0ND "2.50 75-125Surrogate: Dibromofluoromethane 84.02.10 "2.50 75-125Surrogate: 1,2-Dichloroethane-d4 94.02.35 "2.50 75-125Surrogate: Toluene-d8 1243.10 "2.50 75-125Surrogate: 4-Bromofluorobenzene 1082.70 Page 9 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Notes and Definitions Sample results reported on a dry weight basis Relative Percent DifferenceRPD dry Not ReportedNR Analyte NOT DETECTED at or above the reporting limitND Analyte DETECTEDDET Page 10 of 10 Items for Project Manager Review ExceptionAnalyteAnalysisLabNumber E708112-04 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 VERSION 5.8.5:2709 8260B LARWQCB (Vapor)Special Units Used E708112-01 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-01 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-01 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-01 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-02 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-02 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-02 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-03 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-03 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-03 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-02 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 Default Report (not modified) E708112-05 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-06 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-07 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-07 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-07 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-06 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-03 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-06 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-04 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-04 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-05 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-05 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-05 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-04 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-07 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-06 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Sample ID Laboratory ID Matrix Date Sampled ANALYTICAL REPORT FOR SAMPLES Date Received SG14-15, P51cc E708112-01 Vapor 24-Aug-07 24-Aug-07 SG14-5, P21cc E708112-02 Vapor 24-Aug-07 24-Aug-07 SG14-5DUP, P21cc E708112-03 Vapor 24-Aug-07 24-Aug-07 SG13-15, P51cc E708112-04 Vapor 24-Aug-07 24-Aug-07 SG13-5, P21cc E708112-05 Vapor 24-Aug-07 24-Aug-07 SG12-15, P51cc E708112-06 Vapor 24-Aug-07 24-Aug-07 SG12-5, P21cc E708112-07 Vapor 24-Aug-07 24-Aug-07 Page 1 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG14-15, P51cc (E708112-01) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"101 %75-125Surrogate: Dibromofluoromethane """"110 %75-125Surrogate: 1,2-Dichloroethane-d4 """"105 %75-125Surrogate: Toluene-d8 """"107 %75-125Surrogate: 4-Bromofluorobenzene Page 2 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG14-5, P21cc (E708112-02) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"107 %75-125Surrogate: Dibromofluoromethane """"106 %75-125Surrogate: 1,2-Dichloroethane-d4 """"103 %75-125Surrogate: Toluene-d8 """"102 %75-125Surrogate: 4-Bromofluorobenzene Page 3 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG14-5DUP, P21cc (E708112-03) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"113 %75-125Surrogate: Dibromofluoromethane """"113 %75-125Surrogate: 1,2-Dichloroethane-d4 """"102 %75-125Surrogate: Toluene-d8 """"109 %75-125Surrogate: 4-Bromofluorobenzene Page 4 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG13-15, P51cc (E708112-04) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"111 %75-125Surrogate: Dibromofluoromethane """"114 %75-125Surrogate: 1,2-Dichloroethane-d4 """"104 %75-125Surrogate: Toluene-d8 """"106 %75-125Surrogate: 4-Bromofluorobenzene Page 5 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG13-5, P21cc (E708112-05) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"109 %75-125Surrogate: Dibromofluoromethane """"116 %75-125Surrogate: 1,2-Dichloroethane-d4 """"108 %75-125Surrogate: Toluene-d8 """"112 %75-125Surrogate: 4-Bromofluorobenzene Page 6 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG12-15, P51cc (E708112-06) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"105 %75-125Surrogate: Dibromofluoromethane """"115 %75-125Surrogate: 1,2-Dichloroethane-d4 """"102 %75-125Surrogate: Toluene-d8 """"99.6 %75-125Surrogate: 4-Bromofluorobenzene Page 7 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Volatile Organic Compounds by EPA Method 8260B H&P Mobile Geochemistry Result Analyte Limit Reporting Units Dilution Batch Prepared Analyzed Method Notes Factor SG12-5, P21cc (E708112-07) Vapor Sampled: 24-Aug-07 Received: 24-Aug-07 EPA 8260B24-Aug-07 24-Aug-07ug/l EH724030.051,1-Difluoroethane (LCC)10ND """"""Dichlorodifluoromethane 1.0ND """"""Vinyl chloride 1.0ND """"""Chloroethane 1.0ND """"""Trichlorofluoromethane 1.0ND """"""1,1-Dichloroethene 1.0ND """"""Methylene chloride 1.0ND """"""Freon 113 1.0ND """"""trans-1,2-Dichloroethene 1.0ND """"""1,1-Dichloroethane 1.0ND """"""cis-1,2-Dichloroethene 1.0ND """"""Chloroform 1.0ND """"""1,1,1-Trichloroethane 1.0ND """"""Carbon tetrachloride 1.0ND """"""1,2-Dichloroethane 1.0ND """"""Benzene 1.0ND """"""Trichloroethene 1.0ND """"""Toluene 1.0ND """"""1,1,2-Trichloroethane 1.0ND """"""Tetrachloroethene 1.0ND """"""Ethylbenzene 1.0ND """"""1,1,1,2-Tetrachloroethane 1.0ND """"""m,p-Xylene 2.0ND """"""o-Xylene 1.0ND """"""1,1,2,2-Tetrachloroethane 1.0ND """"""Methyl tert-butyl ether 1.0ND """"111 %75-125Surrogate: Dibromofluoromethane """"109 %75-125Surrogate: 1,2-Dichloroethane-d4 """"108 %75-125Surrogate: Toluene-d8 """"102 %75-125Surrogate: 4-Bromofluorobenzene Page 8 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Result Limit Reporting Units Level Spike Result Source %REC %REC Limits RPD RPD Limit Notes Analyte Volatile Organic Compounds by EPA Method 8260B - Quality Control H&P Mobile Geochemistry Batch EH72403 - EPA 5030 Blank (EH72403-BLK1)Prepared & Analyzed: 24-Aug-07 1,1-Difluoroethane (LCC)ug/l10ND Dichlorodifluoromethane "1.0ND Vinyl chloride "1.0ND Chloroethane "1.0ND Trichlorofluoromethane "1.0ND 1,1-Dichloroethene "1.0ND Methylene chloride "1.0ND Freon 113 "1.0ND trans-1,2-Dichloroethene "1.0ND 1,1-Dichloroethane "1.0ND cis-1,2-Dichloroethene "1.0ND Chloroform "1.0ND 1,1,1-Trichloroethane "1.0ND Carbon tetrachloride "1.0ND 1,2-Dichloroethane "1.0ND Benzene "1.0ND Trichloroethene "1.0ND Toluene "1.0ND 1,1,2-Trichloroethane "1.0ND Tetrachloroethene "1.0ND Ethylbenzene "1.0ND 1,1,1,2-Tetrachloroethane "1.0ND m,p-Xylene "2.0ND o-Xylene "1.0ND 1,1,2,2-Tetrachloroethane "1.0ND Methyl tert-butyl ether "1.0ND "2.50 75-125Surrogate: Dibromofluoromethane 84.02.10 "2.50 75-125Surrogate: 1,2-Dichloroethane-d4 94.02.35 "2.50 75-125Surrogate: Toluene-d8 1243.10 "2.50 75-125Surrogate: 4-Bromofluorobenzene 1082.70 Page 9 of 10 Project: Project Number: Project Manager: Reported: SCS Engineers - San Diego 8799 Balboa Avenue, Suite 290 SCS082407-SB1 01207522.00 / 44239 Margarita Rd Mr. Tom WrightSan Diego, CA 92123 12-Sep-07 Notes and Definitions Sample results reported on a dry weight basis Relative Percent DifferenceRPD dry Not ReportedNR Analyte NOT DETECTED at or above the reporting limitND Analyte DETECTEDDET Page 10 of 10 Items for Project Manager Review ExceptionAnalyteAnalysisLabNumber E708112-04 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 VERSION 5.8.5:2709 8260B LARWQCB (Vapor)Special Units Used E708112-01 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-01 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-01 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-01 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-02 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-02 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-02 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-03 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-03 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-03 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-02 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 Default Report (not modified) E708112-05 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-06 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-07 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-07 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-07 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-06 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-03 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-06 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-04 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-04 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-05 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-05 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 E708112-05 8260B LARWQCB 1,2-Dichloroethane-d4 Exceeds FlagLevel 1 E708112-04 8260B LARWQCB Toluene-d8 Exceeds FlagLevel 1 E708112-07 8260B LARWQCB Dibromofluoromethane Exceeds FlagLevel 1 E708112-06 8260B LARWQCB 4-Bromofluorobenzene Exceeds FlagLevel 1 H&P Mobile Geochemistry Standard Operating Procedures For Soil Vapor Sample Collection Soil Vapor Standard Operating Procedures Fulfilling CA-EPA (DTSC) Soil Gas Advisory Revision 4 January 2007 Prepared by: H&P Mobile Geochemistry Carlsbad, California © H&P 2007 1 Soil Gas Sampling Procedures Probe Construction and Insertion Manually-Driven Probes H&P's manually driven soil vapor probes are constructed of 0.625 inch outside diameter steel and equipped with a hardened steel tip. The probes can reach a depth of 5 feet below ground surface. An inert 1/8 inch nylaflow tube is threaded down the center of the probe and connected to a sampling port just above the tip. This internal sample tubing design eliminates any contact between the sample port and the gas sample. The probe is driven into the ground by an electric rotary hammer. Once inserted to the desired depth, the probe is rotated approximately 3 turns to open the tip and exposes the vapor sampling ports. This design prevents clogging of the sampling ports and cross-contamination from soils during insertion. Hydraulically-Driven Probes H&P’s hydraulically-driven soil vapor probes are constructed of either 1.25 or 1.5 inch outside diameter steel and equipped with a hardened drop-off steel tip. The probes are nominally 4 feet long and threaded together to reach multiple depths. The probe is driven into the subsurface with H&P's STRATAPROBETM direct-push system. Once inserted to the desired depth, the probe is retracted slightly to expose the vapor sampling port. A small diameter inert tubing is then inserted through the center of the rod and threaded into a gas tight fitting just above the tip. After a sample is obtained the tubing is removed and the probe rod advanced to the next sampling depth or removed. This design prevents clogging of the sampling port and cross- contamination from soils during insertion. Surface Seals The probe rod is sealed at the surface with granular and hydrated bentonite for a minimum of 20 minutes before sampling. © H&P 2007 2 Soil Gas Sampling Soil vapor is withdrawn from the end of the inert nylaflow tubing that runs from the sampling tip to the surface using a 20 to 60 cubic centimeter (cc) syringe or gas tight canister (Summa) connected via an on-off valve (see diagram). The probe tip and sampling tubing is nominally purged of three to five internal dead volumes, or based upon a pre-determined purge volume established by a purge volume test described below. A sample of in-situ soil vapor is then withdrawn and immediately transferred to the mobile lab for analysis within minutes of collection. The use of small calibrated syringes allowed for careful monitoring of purge and sample volumes. This procedure ensures adequate sample flow is obtained without excessive pumping of air or introduction of surface air into the sample. For off-site analysis, samples are collected in canisters or in tedlar bags when allowed. Samples collected in tedlar bags for VOC analysis are either analyzed on the same day or transferred to a canister. Purge Volume Test If required, a site specific purge volume test is conducted at the beginning of the soil gas survey to purge ambient air from the sampling system. Three different volumes are sampled (nominally 1, 3, 7 purge volumes) and analyzed immediately to determine the volume amount with the highest concentration. Therefore, the optimum purge volume is achieved and used during the entire site investigation. Use of Tracer Compound to Ensure Probe Seal Integrity A tracer compound, typically difluoroethane, iso-propanol, or butane, is used to test for leaks around the probe barrel at the ground surface and in the sampling system. The tracer is placed around the base of the probe barrel and at the top of the probe barrel during sample collection. If the tracer is detected per CA-EPA advisory specifications, another sample is collected. Sample Flow Rate Sample collection is timed so that the flow rate does not exceed 200 ml/per minute. This is accomplished by withdrawing the plunger on the 60 cc syringe at a constant rate for 20 seconds. The collector notes the collection time on a logsheet, and also records any resistance to sample flow that is felt on the syringe during collection. © H&P 2007 3 Summa Canister Summa canisters are connected to the end of the nylaflow tubing to the same three way valve used with the syringe. A choke is placed on the canister to ensure that the flow rate is no more than 200 ml/ per minute into the summa canister. Field Records The field technician maintains a logsheet summarizing: • Sample identification • Probe location • Date and time of sample collection • Sampling depth • Identity of samplers • Weather conditions • Sampling methods and devices • Soil gas purge volumes • Volume of soil gas extracted • Observation of soil or subsurface characteristics (any condition that affects sample integrity) • Apparent moisture content (dry, moist or saturated etc.) of the sampling zone • Chain of custody protocols and records used to track samples from sampling point to analysis. © H&P 2007 4 Analytical Methodology The following analytical protocols fulfills the both the CA-EPA advisory (2003) and LA-RWQCB soil gas analytical guidelines (1997). Operating Conditions and Instrumentation Volatile Organic Compounds (VOCs) by EPA 8260 Instrument: Hewlett-Packard 6890(6850)/5973 or 5890/5972 GCMS Column: 25 meter HP-624, 0.20mm x 1.0u. capillary. Carrier flow: Helium at 1.0 ml/min. Detectors: Quadrupole MS, full scan mode Concentrator: Tekmar 3000/Solatek 72 Volatile Organic Compounds (VOCs) by EPA TO-14 or TO-15 Instrument: Hewlett-Packard 6850/5973 Column: 60 meter HP-624, 0.32mm x 1.8u. capillary. Carrier flow: Helium at 3.0 ml/min. Detectors: Quadrupole MS, full scan mode TO-14 Instrumentation: Entech 7100 Air Concentrator/Entech 7300 Autosampler Fixed and Biogenic Gases (O2, CO2, & Methane) Instrument: SRI 8610 or Carle AGC 311 Gas Chromatograph Column: 6 foot CTR Carrier flow: Helium at 15 ml/min. Detectors: Thermoconductivity (TCD) for O2 & CO2. Detectors: Flame ionization detector (FID) for methane. Hydrogen Sulfide Instrument: Jerome 631x Detectors: Gold-film Standard Preparation Primary (stock) standards: Made from certified neat components or from traceable standards purchased from certified suppliers. Secondary (working) Standards: Made by diluting primary standard. Typical concentrations are 1ug/ml, 10 ug/ml, and 50 ug/ml. Laboratory Check Samples are prepared at the midpoint concentration from a standard purchased from a source different than the primary standards. © H&P 2007 5 Lot numbers and preparations of all standards are recorded on a log sheet and kept in the mobile laboratory. Gas Standards for TO-14A/15 analysis purchased from Spectra Gases, Branchburg, N.J. diluted from 1.0 ppmv to 10ppbv (for targets) and 1.0ppmv to 100ppbv (internal standards and surrogates Initial Multi-Point Calibration Curve An initial calibration curve of a minimum of 3 points is performed either: • At the start of the project. • When the GC column or operating conditions have changed • When the daily mid-point calibration check cannot meet the requirements as specified below. • For TO-15 a five point calibration is used. Calibration curves for each target component are prepared by analyzing low, mid, and high calibration standards covering the expected concentration range. The lowest standard concentration will not exceed 5 times the reporting limit for each compound. A linearity check of the calibration curve for each compound is performed by computing a correlation coefficient and an average response factor. If a correlation coefficient of 0.990 or a percent relative standard deviation (%RSD) of + 15% is obtained, an average response factor is used over the entire calibration range. If the linearity criteria are not obtained, quantitation for that analyte is performed using a calibration curve. After each initial multi-point calibration, the validity of the curve is further verified with a laboratory control standards (LCS) prepared at the mid-point of the calibration range. The LCS includes all target compounds and the response factor (RF) must fall within + 20% of the factor from the initial calibration curve. Continuing Calibration (Daily Mid-point Calibration Check) Continuing calibration standards prepared from a traceable source are analyzed at the beginning of each day. Acceptable continuing calibration agreement is set at + 20% to the average response factor from the calibration curve, except for freon, chloroethane, and vinyl chloride when a 25% agreement is required. When calibration checks fall outside this acceptable range for analytes detected on the site, corrective action, consisting of verification of the standard and/or a new calibration curve for the analytes out of specifications is performed by the on-site chemist. © H&P 2007 6 The continuing calibration includes all compounds expected or detected at the site in addition to any specific compounds designated in the project workplan. Detection Limits Reporting limits for this program are defined as 5 times lower than the lowest concentration standard of the calibration curve, as follows: Compound Detector Report Limit VOCs by TO-14A/15 Mass Spec 1.0 to 5 ppbv VOCs Mass Spec 0.1 to 1 ug/l-vapor Methane FID 10 ppmv Fixed Gases TCD 0.1% by vol H2S Gold Film 0.10 ppmv Injection of Soil Gas Samples Vapor samples are withdrawn from the probe sampling syringe with a 5 cc syringe and injected with surrogates into a purge & trap instrument for VOC analysis. Separate aliquots are directly injected into gas chromatographs for fixed gases and methane analysis. The injection syringe is flushed 2 times with the sample prior to injection. Injection syringes are flushed several times with clean air or discarded between injections. TO-14A/15 samples are taken into Summa or similar passivated canisters. Holding time for these canisters is 30 days. Laboratory Data Logs The field chemist maintains injection and sample analysis records including date and time of analysis, sampler's name, chemist's name, sample ID number, concentrations of compounds detected, calibration data, and any unusual conditions. © H&P 2007 7 Quality Control Procedures Compliance With Standards Sampling and analytical procedures complied with the American Society for Testing and Materials' Standard Guide for Soil Gas Monitoring in the Vadose Zone (ASTM D5314-93), the LA-RWQCB Soil Gas Guidelines (Feb 1997 version), and the San Diego County SAM Soil Gas Guidelines (October, 2001). Sampling Quality Control Method Blanks Prior to sampling each day, all components of the sampling system are checked for contamination by drawing ambient air from above ground through the sampling equipment, and injecting a sample into a gas chromatograph. The analysis results are compared to that of the ambient air and recorded in the data tables as blanks. Sample Quality Control Each sample is given a unique identification number specifying location and depth. Purge and sample volumes are monitored closely using small calibrated syringes to assure a proper flow of soil gas. This ensures a representative sample is obtained from the sample zone without excessive pumping, which could result in sampling of surface air. Decontamination Procedures To minimize the potential for cross-contamination between sites, all external soil vapor probe parts are wiped or washed cleaned of excess dirt and moisture with solvents or de-ionized water as appropriate. The probe’s internal nylaflow tubing is purged with clean air between sampling locations or replaced as necessary. Sampling syringes are flushed with clean air after each use or replaced. Corrective Action Corrective action is taken when unexpected contaminant levels are detected. First duplicate samples are taken to verify the initial detection of petroleum hydrocarbons. If contamination is suspected, then the sample probes are disassembled, wiped cleaned of excess dirt and moisture, rinsed with deionized water, washed with Alconox and water, and rinsed again with © H&P 2007 8 deionized water. The sample tubing in the probe is replaced. Contaminated sampling syringes are discarded. Analytical Quality Control Method Blanks Method blanks are performed at the start of each day by drawing clean air through the sampling equipment and analyzing. These blanks verify all components of the sampling and analytical system are free of contamination. Additional blanks are performed more often as appropriate depending upon the measured concentrations, at a minimum 1 every 20 samples. The results of all blank analyses are recorded in the data tables. If a blank shows a measurable amount of any target compound, the on-site chemist will investigate and determine the source, and resolve the contamination problem prior to analyzing any samples. Duplicate Samples Duplicate (repetitive) analysis of a sample is performed when inconsistent data are observed, but at least one every 20 samples. Because soil vapor duplicates can vary widely, nominal relative percent difference (RPD) acceptance criteria is + a factor of 2. Continuing Calibration (Daily Mid-point Calibration Check) As described on page 5 of this document, continuing calibration standards prepared from a traceable source are analyzed at the beginning of each day. The continuing calibration includes all compounds expected or detected at the site and any specific compounds designated in the project workplan. Laboratory Check Samples (LCS) Laboratory check samples, prepared at the lowpoint concentration from a standard purchased from a source different than the calibration standards, are analyzed at the end of each day if all samples are below detection. Acceptance criteria is + 20% from the true value. If the LCS falls outside this acceptance range for analytes detected on site, corrective action, consisting of verification of the standard and/or a new calibration curve for the analytes out of specifications, is performed. DTSC’s Screening-Level Model for Groundwater Contamination Spreadsheets DA T A E N T R Y S H E E T CA L C U L A T E R I S K - B A S E D G R O U N D W A T E R C O N C E N T R A T I O N ( e n t e r " X " i n " Y E S " b o x ) DT S C Va p o r I n t r u s i o n G u i d a n c e YE S In t e r i m F i n a l 1 2 / 0 4 OR (la s t m o d i f i e d 1 / 2 1 / 0 5 ) CA L C U L A T E I N C R E M E N T A L R I S K S F R O M A C T U A L G R O U N D W A T E R C O N C E N T R A T I O N (e n t e r " X " i n " Y E S " b o x a n d i n i t i a l g r o u n d w a t e r c o n c . b e l o w ) YE S X EN T E R E N T E R In i t i a l Ch e m i c a l g r o u n d w a t e r CA S N o . c o n c . , (n u m b e r s o n l y , C W no d a s h e s ) (μ g /L ) 16 3 4 0 4 4 9 . 7 0 E + 0 1 MT B E EN T E R E N T E R E N T E R E N T E R MO R E De p t h Ð be l o w g r a d e A v e r a g e EN T E R to b o t t o m D e p t h s o i l / A v e r a g e v a p o r of e n c l o s e d b e l o w g r a d e S C S g r o u n d w a t e r f l o w r a t e i n t o b l d g . sp a c e f l o o r , t o w a t e r t a b l e , s o i l t y p e t e m p e r a t u r e , ( L e a v e b l a n k t o c a l c u l a t e ) L F L W T di r e c t l y a b o v e T S Q so i l (c m ) ( c m ) w a t e r t a b l e (o C) (L / m ) 15 7 9 2 S 2 4 8 2 7 MO R E Ð EN T E R E N T E R Va d o s e z o n e U s e r - d e f i n e d EN T E R E N T E R E N T E R E N T E R SC S v a n d o s e z o n e V a d o s e z o n e V a d o s e z o n e V a d o s e z o n e V a d o s e z o n e so i l t y p e s o i l v a p o r S C S s o i l d r y s o i l t o t a l s o i l w a t e r - f i l l e d (u s e d t o e s t i m a t e OR pe r m e a b i l i t y , s o i l t y p e b u l k d e n s i t y , p o r o s i t y , p o r o s i t y , so i l v a p o r k v ρ bV n V θ wV pe r m e a b i l i t y ) (c m 2 ) ( g / c m 3 ) (u n i t l e s s ) (c m 3 /c m 3 ) S S 1. 6 6 0.3 7 5 0 . 0 5 4 MO R E Ð EN T E R E N T E R E N T E R E N T E R E N T E R E N T E R Ta r g e t T a r g e t h a z a r d A v e r a g i n g A v e r a g i n g ris k f o r q u o t i e n t f o r t i m e f o r t i m e f o r E x p o s u r e E x p o s u r e ca r c i n o g e n s , n o n c a r c i n o g e n s , c a r c i n o g e n s , n o n c a r c i n o g e n s , d u r a t i o n , f r e q u e n c y , TR T H Q A T C AT N C ED E F (u n i t l e s s ) ( u n i t l e s s ) ( y r s ) ( y r s ) ( y r s ) ( d a y s / y r ) 1.0 E - 0 6 1 7 0 3 0 3 0 3 5 0 Us e d t o c a l c u l a t e r i s k - b a s e d gr o u n d w a t e r c o n c e n t r a t i o n . EN D Ch e m i c a l GW - S C R E E N Ve r s i o n 3 . 0 ; 0 4 / 0 3 Re s e t t o De f a u l t s Lo o k u p S o i l Pa r a m e t e r s DT S C / H E R D La s t U p d a t e : 1 1 / 1 / 0 3 DT S C I n d o o r A i r G u i d a n c e Un c l a s s i f i e d S o i l S c r e e n i n g M o d e l Copy of HERD_GW_Screening_2005_97ugl.xls 9/28/2007 1:10 PM CH E M I C A L P R O P E R T I E S S H E E T AB C He n r y ' s H e n r y ' s E n t h a l p y o f O r g a n i c P u r e la w c o n s t a n t l a w c o n s t a n t v a p o r i z a t i o n a t N o r m a l c a r b o n c o m p o n e n t U n i t Dif f u s i v i t y D i f f u s i v i t y a t r e f e r e n c e r e f e r e n c e t h e n o r m a l b o i l i n g C r i t i c a l p a r t i t i o n w a t e r r i s k R e f e r e n c e in a i r , i n w a t e r , t e m p e r a t u r e , t e m p e r a t u r e , b o i l i n g p o i n t , p o i n t , t e m p e r a t u r e , c o e f f i c i e n t , s o l u b i l i t y , f a c t o r , c o n c . , D a D w HT R Δ H v,b T B T C K oc S U R F R f C (c m 2 /s ) ( c m 2 /s ) ( a t m - m 3 /m o l ) ( o C) (c a l / m o l ) (o K) ( o K) ( c m 3 /g ) (m g / L ) (μ g/ m 3 )-1 (m g / m 3 ) 1. 0 2 E - 0 1 1 . 0 5 E - 0 5 6 . 2 3 E - 0 4 2 5 6 , 6 7 8 3 2 8 . 3 0 4 9 7 . 1 0 7 . 2 6 E + 0 0 5 . 1 0 E + 0 4 2 . 6 E - 0 7 3 . 0 E + 0 0 EN D 2 o f 4 IN T E R M E D I A T E C A L C U L A T I O N S S H E E T Va d o s e V a d o s e z o n e V a d o s e z o n e V a d o s e z o n e V a d o s e z o n e T o t a l A i r - f i l l e d W a t e r - f i l l e d F l o o r - So u r c e - z o n e s o i l e f f e c t i v e s o i l s o i l s o i l T h i c k n e s s o f p o r o s i t y i n p o r o s i t y i n p o r o s i t y i n w a l l bu i l d i n g a i r - f i l l e d t o t a l f l u i d i n t r i n s i c r e l a t i v e a i r e f f e c t i v e v a p o r c a p i l l a r y c a p i l l a r y c a p i l l a r y c a p i l l a r y s e a m se p a r a t i o n , p o r o s i t y , s a t u r a t i o n , p e r m e a b i l i t y , p e r m e a b i l i t y , p e r m e a b i l i t y , z o n e , z o n e , z o n e , z o n e , p e r i m e t e r , L T θ aV S te k i k r g k v L cz n cz θ a,c z θ w,c z X crac k (c m ) (c m 3 /c m 3 ) ( c m 3 /c m 3 ) ( c m 2 ) ( c m 2 ) ( c m 2 ) (c m ) (c m 3 /c m 3 ) ( c m 3 /c m 3 ) ( c m 3 /c m 3 ) (cm) 77 7 0 . 3 2 1 0 . 0 0 3 1 . 0 2 E - 0 7 0 . 9 9 8 1 . 0 1 E - 0 7 1 7 . 0 5 0 . 3 7 5 0 . 1 2 2 0 . 2 5 3 4 , 0 0 0 Ar e a o f Ca p i l l a r y T o t a l en c l o s e d C r a c k - C r a c k E n t h a l p y o f H e n r y ' s l a w H e n r y ' s l a w V a p o r V a d o s e z o n e z o n e o v e r a l l Bl d g . s p a c e t o - t o t a l d e p t h v a p o r i z a t i o n a t c o n s t a n t a t c o n s t a n t a t v i s c o s i t y a t e f f e c t i v e e f f e c t i v e e f f e c t i v e ve n t i l a t i o n b e l o w a r e a b e l o w a v e . g r o u n d w a t e r a v e . g r o u n d w a t e r a v e . g r o u n d w a t e r a v e . s o i l d i f f u s i o n d i f f u s i o n d i f f u s i o n ra t e , g r a d e , r a t i o , g r a d e , t e m p e r a t u r e , t e m p e r a t u r e , t e m p e r a t u r e , t e m p e r a t u r e , c o e f f i c i e n t , c o e f f i c i e n t , c o e f f i c i e n t , Q bu i l d i n g A B η Z cr a c k Δ H v,T S H TS H'TS μ TS D eff V D eff cz D eff T (c m 3 /s ) ( c m 2 ) (u n i t l e s s ) ( c m ) ( c a l / m o l ) (a t m - m 3 /m o l ) (u n i t l e s s ) ( g / c m - s ) (c m 2 /s ) ( c m 2 /s ) ( c m 2 /s) 3. 3 9 E + 0 4 1 . 0 0 E + 0 6 5 . 0 0 E - 0 3 1 5 7 , 1 1 3 5 . 9 9 E - 0 4 2 . 4 6 E - 0 2 1 . 8 0 E - 0 4 1 . 6 6 E - 0 2 6 . 8 7 E - 0 4 1 . 1 0 E - 0 2 Ex p o n e n t o f I n f i n i t e Av e r a g e C r a c k e q u i v a l e n t s o u r c e I n f i n i t e Di f f u s i o n C o n v e c t i o n S o u r c e v a p o r e f f e c t i v e f o u n d a t i o n i n d o o r s o u r c e U n i t pa t h p a t h v a p o r C r a c k f l o w r a t e d i f f u s i o n A r e a o f P e c l e t a t t e n u a t i o n b l d g . r i s k R e f e r e n c e le n g t h , l e n g t h , c o n c . , r a d i u s , i n t o b l d g . , c o e f f i c i e n t , c r a c k , n u m b e r , c o e f f i c i e n t , c o n c . , f a c t o r , c o n c . , L d L p C so u r c e r cra c k Q so i l D cra c k A cr a c k ex p ( P e f ) α C bu i l d i n g URF RfC (c m ) ( c m ) (μ g/ m 3 ) (c m ) (c m 3 /s ) ( c m 2 /s ) ( c m 2 ) (u n i t l e s s ) ( u n i t l e s s ) (μ g/ m 3 )(μ g/m 3 )-1 (mg/m 3 ) 77 7 1 5 2 . 3 8 E + 0 3 1 . 2 5 1 . 3 8 E + 0 4 1 . 6 6 E - 0 2 5 . 0 0 E + 0 3 # N U M ! 4 . 1 7 E - 0 4 9 . 9 3 E - 0 1 2 . 6 E - 0 7 3 . 0 E + 0 0 DT S C / H E R D La s t U p d a t e : 1 1 / 1 / 0 3 DT S C I n d o o r A i r G u i d a n c e Un c l a s s i f i e d S o i l S c r e e n i n g M o d e l Co p y o f H E R D _ G W _ S c r e e n i n g _ 2 0 0 5 _ 9 7 u g l . x l s 9/28/2007 1:10 PM RE S U L T S S H E E T RI S K - B A S E D G R O U N D W A T E R C O N C E N T R A T I O N C A L C U L A T I O N S : I N C R E M E N T A L R I S K C A L C U L A T I O N S : In c r e m e n t a l H a z a r d In d o o r I n d o o r R i s k - b a s e d P u r e F i n a l r i s k f r o m q u o t i e n t ex p o s u r e e x p o s u r e i n d o o r c o m p o n e n t i n d o o r v a p o r f r o m v a p o r gr o u n d w a t e r g r o u n d w a t e r e x p o s u r e w a t e r e x p o s u r e i n t r u s i o n t o i n t r u s i o n t o co n c . , c o n c . , g r o u n d w a t e r s o l u b i l i t y , g r o u n d w a t e r i n d o o r a i r , i n d o o r a i r , ca r c i n o g e n n o n c a r c i n o g e n c o n c . , S c o n c . , c a r c i n o g e n n o n c a r c i n o g e n (μ g/ L ) ( μ g/ L ) ( μ g/ L ) ( μ g/ L ) ( μ g/ L ) (u n i t l e s s ) ( u n i t l e s s ) NA N A N A 5. 1 0 E + 0 7 N A 1. 1 E - 0 7 3 . 2 E - 0 4 ME S S A G E S U M M A R Y B E L O W : EN D 4 o f 4 DA T A E N T R Y S H E E T CA L C U L A T E R I S K - B A S E D G R O U N D W A T E R C O N C E N T R A T I O N ( e n t e r " X " i n " Y E S " b o x ) DT S C Va p o r I n t r u s i o n G u i d a n c e YE S In t e r i m F i n a l 1 2 / 0 4 OR (la s t m o d i f i e d 1 / 2 1 / 0 5 ) CA L C U L A T E I N C R E M E N T A L R I S K S F R O M A C T U A L G R O U N D W A T E R C O N C E N T R A T I O N (e n t e r " X " i n " Y E S " b o x a n d i n i t i a l g r o u n d w a t e r c o n c . b e l o w ) YE S X EN T E R E N T E R In i t i a l Ch e m i c a l g r o u n d w a t e r CA S N o . c o n c . , (n u m b e r s o n l y , C W no d a s h e s ) (μ g /L ) 16 3 4 0 4 4 1 . 3 0 E + 0 0 MT B E EN T E R E N T E R E N T E R E N T E R MO R E De p t h Ð be l o w g r a d e A v e r a g e EN T E R to b o t t o m D e p t h s o i l / A v e r a g e v a p o r of e n c l o s e d b e l o w g r a d e S C S g r o u n d w a t e r f l o w r a t e i n t o b l d g . sp a c e f l o o r , t o w a t e r t a b l e , s o i l t y p e t e m p e r a t u r e , ( L e a v e b l a n k t o c a l c u l a t e ) L F L W T di r e c t l y a b o v e T S Q so i l (c m ) ( c m ) w a t e r t a b l e (o C) (L / m ) 15 7 9 2 S 2 4 3 7 MO R E Ð EN T E R E N T E R Va d o s e z o n e U s e r - d e f i n e d EN T E R E N T E R E N T E R E N T E R SC S v a n d o s e z o n e V a d o s e z o n e V a d o s e z o n e V a d o s e z o n e V a d o s e z o n e so i l t y p e s o i l v a p o r S C S s o i l d r y s o i l t o t a l s o i l w a t e r - f i l l e d (u s e d t o e s t i m a t e OR pe r m e a b i l i t y , s o i l t y p e b u l k d e n s i t y , p o r o s i t y , p o r o s i t y , so i l v a p o r k v ρ bV n V θ wV pe r m e a b i l i t y ) (c m 2 ) ( g / c m 3 ) (u n i t l e s s ) (c m 3 /c m 3 ) S S 1. 6 6 0.3 7 5 0 . 0 5 4 MO R E Ð EN T E R E N T E R E N T E R E N T E R E N T E R E N T E R Ta r g e t T a r g e t h a z a r d A v e r a g i n g A v e r a g i n g ris k f o r q u o t i e n t f o r t i m e f o r t i m e f o r E x p o s u r e E x p o s u r e ca r c i n o g e n s , n o n c a r c i n o g e n s , c a r c i n o g e n s , n o n c a r c i n o g e n s , d u r a t i o n , f r e q u e n c y , TR T H Q A T C AT N C ED E F (u n i t l e s s ) ( u n i t l e s s ) ( y r s ) ( y r s ) ( y r s ) ( d a y s / y r ) 1.0 E - 0 6 1 7 0 3 0 3 0 3 5 0 Us e d t o c a l c u l a t e r i s k - b a s e d gr o u n d w a t e r c o n c e n t r a t i o n . EN D Ch e m i c a l GW - S C R E E N Ve r s i o n 3 . 0 ; 0 4 / 0 3 Re s e t t o De f a u l t s Lo o k u p S o i l Pa r a m e t e r s DT S C / H E R D La s t U p d a t e : 1 1 / 1 / 0 3 DT S C I n d o o r A i r G u i d a n c e Un c l a s s i f i e d S o i l S c r e e n i n g M o d e l Copy of HERD_GW_Screening_2005_1.3ugl.xls 9/28/2007 1:09 PM CH E M I C A L P R O P E R T I E S S H E E T AB C He n r y ' s H e n r y ' s E n t h a l p y o f O r g a n i c P u r e la w c o n s t a n t l a w c o n s t a n t v a p o r i z a t i o n a t N o r m a l c a r b o n c o m p o n e n t U n i t Dif f u s i v i t y D i f f u s i v i t y a t r e f e r e n c e r e f e r e n c e t h e n o r m a l b o i l i n g C r i t i c a l p a r t i t i o n w a t e r r i s k R e f e r e n c e in a i r , i n w a t e r , t e m p e r a t u r e , t e m p e r a t u r e , b o i l i n g p o i n t , p o i n t , t e m p e r a t u r e , c o e f f i c i e n t , s o l u b i l i t y , f a c t o r , c o n c . , D a D w HT R Δ H v,b T B T C K oc S U R F R f C (c m 2 /s ) ( c m 2 /s ) ( a t m - m 3 /m o l ) ( o C) (c a l / m o l ) (o K) ( o K) ( c m 3 /g ) (m g / L ) (μ g/ m 3 )-1 (m g / m 3 ) 1. 0 2 E - 0 1 1 . 0 5 E - 0 5 6 . 2 3 E - 0 4 2 5 6 , 6 7 8 3 2 8 . 3 0 4 9 7 . 1 0 7 . 2 6 E + 0 0 5 . 1 0 E + 0 4 2 . 6 E - 0 7 3 . 0 E + 0 0 EN D 2 o f 4 IN T E R M E D I A T E C A L C U L A T I O N S S H E E T Va d o s e V a d o s e z o n e V a d o s e z o n e V a d o s e z o n e V a d o s e z o n e T o t a l A i r - f i l l e d W a t e r - f i l l e d F l o o r - So u r c e - z o n e s o i l e f f e c t i v e s o i l s o i l s o i l T h i c k n e s s o f p o r o s i t y i n p o r o s i t y i n p o r o s i t y i n w a l l bu i l d i n g a i r - f i l l e d t o t a l f l u i d i n t r i n s i c r e l a t i v e a i r e f f e c t i v e v a p o r c a p i l l a r y c a p i l l a r y c a p i l l a r y c a p i l l a r y s e a m se p a r a t i o n , p o r o s i t y , s a t u r a t i o n , p e r m e a b i l i t y , p e r m e a b i l i t y , p e r m e a b i l i t y , z o n e , z o n e , z o n e , z o n e , p e r i m e t e r , L T θ aV S te k i k r g k v L cz n cz θ a,c z θ w,c z X crac k (c m ) (c m 3 /c m 3 ) ( c m 3 /c m 3 ) ( c m 2 ) ( c m 2 ) ( c m 2 ) (c m ) (c m 3 /c m 3 ) ( c m 3 /c m 3 ) ( c m 3 /c m 3 ) (cm) 77 7 0 . 3 2 1 0 . 0 0 3 1 . 0 2 E - 0 7 0 . 9 9 8 1 . 0 1 E - 0 7 1 7 . 0 5 0 . 3 7 5 0 . 1 2 2 0 . 2 5 3 4 , 0 0 0 Ar e a o f Ca p i l l a r y T o t a l en c l o s e d C r a c k - C r a c k E n t h a l p y o f H e n r y ' s l a w H e n r y ' s l a w V a p o r V a d o s e z o n e z o n e o v e r a l l Bl d g . s p a c e t o - t o t a l d e p t h v a p o r i z a t i o n a t c o n s t a n t a t c o n s t a n t a t v i s c o s i t y a t e f f e c t i v e e f f e c t i v e e f f e c t i v e ve n t i l a t i o n b e l o w a r e a b e l o w a v e . g r o u n d w a t e r a v e . g r o u n d w a t e r a v e . g r o u n d w a t e r a v e . s o i l d i f f u s i o n d i f f u s i o n d i f f u s i o n ra t e , g r a d e , r a t i o , g r a d e , t e m p e r a t u r e , t e m p e r a t u r e , t e m p e r a t u r e , t e m p e r a t u r e , c o e f f i c i e n t , c o e f f i c i e n t , c o e f f i c i e n t , Q bu i l d i n g A B η Z cr a c k Δ H v,T S H TS H'TS μ TS D eff V D eff cz D eff T (c m 3 /s ) ( c m 2 ) (u n i t l e s s ) ( c m ) ( c a l / m o l ) (a t m - 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0 9 4 . 2 E - 0 6 ME S S A G E S U M M A R Y B E L O W : EN D 4 o f 4 USER'S GUIDE FOR EVALUATING SUBSURFACE VAPOR INTRUSION INTO BUILDINGS Prepared By Environmental Quality Management, Inc. Cedar Terrace Office Park, Suite 250 3325 Durham-Chapel Hill Boulevard Durham, North Carolina 27707-2646 Prepared For Industrial Economics Incorporated 2667 Massachusetts Avenue Cambridge, Massachusetts 02140 Subcontract No. 3073-002 EPA Contract Number: 68-W-01-058 PN 030224.0001 For Submittal to Janine Dinan, Work Assignment Manager U.S. ENVIRONMENTAL PROTECTION AGENCY OFFICE OF EMERGENCY AND REMEDIAL RESPONSE ARIEL RIOS BUILDING, 5202G 1200 PENNSYLVANIA AVENUE, NW WASHINGTON, D.C. 20460 June 19, 2003 DISCLAIMER This document presents technical and policy recommendations based on current understanding of the phenomenon of subsurface vapor intrusion. This guidance does not impose any requirements or obligations on the U.S. Environmental Protection Agency (EPA) or on the owner/operators of sites that may be contaminated with volatile and toxic compounds. The sources of authority and requirements for addressing subsurface vapor intrusion are the applicable and relevants statutes and regulations.. This guidance addresses the assumptions and limitations that need to be considered in the evaluation of the vapor intrusion pathway. This guidance provides instructions on the use of the vapor transport model that originally was developed by P. Johnson and R. Ettinger in 1991 and subsequently modified by EPA in 1998, 2001, and again in November 2002. On November 29, 2002 EPA published Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Federal Register: November 29, 2002 Volume 67, Number 230 Page 71169-71172). This document is intended to be a companion for that guidance. Users of this guidance are reminded that the science and policies concerning vapor intrusion are complex and evolving. ii CONTENTS Figures v Tables vi Acknowledgment vii What's New in this Version viii 1. Introduction to the Vapor Intrusion Model Theory and Application 1 2. Model Theory 3 2.1 Model Setting 3 2.2 Vapor Concentration at the Source of Contamination 6 2.3 Diffusion Through the Capillary Zone 14 2.4 Diffusion Through the Unsaturated Zone 19 2.5 The Infinite Source Solution to Convective and Diffusive Transport 20 2.6 The Finite Source Solution to Convective and Diffusive Transport 24 2.7 The Soil Gas Models 26 2.8 Soil Vapor Permeability 26 2.9 Calculation of a Risk-Based Soil or Groundwater Concentration 28 2.10 Calculation of Incremental Risks 30 2.11 Major Model Assumptions/Limitations 30 3. Soil and Groundwater Model Application 33 3.1 Justification of Default Soil-Dependent Properties 37 3.2 Justification of Default Building-Related Properties 38 3.3 Running the Models 41 3.4 The Data Entry Sheet (DATENTER) 42 3.5 The Results Sheet (RESULTS) 57 3.6 The Chemical Properties Sheet (CHEMPROPS) 58 3.7 The Intermediate Calculations Sheet (INTERCALCS) 58 3.8 The Lookup Tables (VLOOKUP) 58 3.9 Adding, Deleting, or Revising Chemicals 58 iii CONTENTS (continued) 4. Soil Gas Model Application 60 4.1 Running the Models 60 4.2 Soil Gas Sampling 61 4.3 Assumptions and Limitations of the Soil Gas Models 65 5. Assumptions and Limitations of the J&E Model 67 5.1 Source Vapor Concentration 73 5.2 Soil Vapor Permeability 74 5.3 Rise of and Diffusion Across the Capillary Zone 74 5.4 Diffusive and Convective Transport into the Structure 75 6. Interpretation of Results 77 Appendices A. User’s Guide for Non-Aqueous Phase Liquids A-1 B. Chemical Properties Lookup Table and References B-1 C. Example Worksheets for the Advanced Soil Contamination Model C-1 D. Sample Data Entry Sheets for Each Model D-1 E. Bibliography and Reference List E-1 iv FIGURES Number Page 1 Pathway for Subsurface Vapor Intrusion into Indoor Air 4 2 Vapor Pathway into Buildings 5 3 U.S. Soil Conservation Service Classification Chart Showing Centroid Compositions (Solid Circles) 18 4 GW-SCREEN Data Entry Sheet 43 5 GW-ADV Data Entry Sheet 44 6 Example Error Message on Data Entry Sheet 46 7 Example Error Message on Results Sheet 46 8 Average Shallow Groundwater Temperature in the United States 48 9 Floor Slab and Foundation 55 10 SG-ADV Data Entry Sheet 62 v TABLES Number Page 1 Screening List of Chemicals 7 2 Values of Exponent n as a Function of TB/TC 13 3 Class Average Values of the Van Genuchten Soil Water Retention Parameters for the 12 SCS Soil Textural Classifications 16 4 Centroid Compositions, Mean Particle Diameters and Dry Bulk Density of the 12 SCS Soil Textural Classifications 19 5 Class Average Values of Saturated Hydraulic Conductivity for the 12 SCS Soil Textural Classifications 27 6 Uncertainty and Sensitivity of Key Parameters for the Vapor Intrusion Model 32 7 Range of Values for Selected Model Input Parameters 34 8 Effect on Building Concentration from an Increase in Input Parameter Values 35 9 Building-Related Parameters for the Vapor Intrusion Model 36 10 Soil-Dependent Properties for the Vapor Intrusion Model First Tier Assessment 37 11 Guidance for Selection of Soil Type 37 12 Assumptions and Limitations of the Vapor Intrusion Model 68 vi ACKNOWLEDGMENT Environmental Quality Management, Inc. (EQ) via Industrial Economics Incorporated (IEC) Subcontract No. 3073-002 prepared this document and the accompanying spreadsheets for the U.S. Environmental Protection Agency (EPA). Mr. Tom Robertson (EQ Project Manager) and Mr. Henry Roman (IEC Project Manager) managed the project. The work was completed on behalf of the U.S. EPA Office of Solid Waste. Ms. Janine Dinan was the government’s Project Manager. EPA IEC EQ Golder Associates Helen Dawson Janine Dinan Debbie Newberry Henry Schuver Adena Greenbaum Henry Roman Eric Ruder Dave Dunbar Josh Dunbar Tena Pipkin Tom Robertson Mr. Ian Hers vii WHAT’S NEW IN THIS VERSION! This revised version of the User's Guide corresponds with the release of Version 3.0 of the Johnson and Ettinger (1991) model (J&E) spreadsheets for estimating subsurface vapor intrusion into buildings. Several things have changed within the models since Version 2 was released in December 2000 and since the original version was released in September 1998. The following represent the major changes in Version 3.0 to be consistent with Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Quality from Groundwater and Soils dated November 25, 2002 as referenced below: 1. Table 1 lists the chemicals that are commonly found at contaminated sites. This list has been expanded from the list of chemicals included in Version 2 of the model. We have also applied certain criteria to determine whether it is appropriate to run the model for these contaminants. Only those contaminants for which all of the toxicological or physical chemical properties needed to make an assessment of the indoor inhalation risk are included in the spreadsheets. A chemical is considered to be sufficiently toxic if the vapor concentration of the pure component poses an incremental life time cancer risk greater than 1 x 10-6 or the noncancer hazard index is greater than 1. A chemical is considered to be sufficiently volatile if its Henry’s law constant is 1 x 10-5 atm-m3/mole or greater. The final chemical list for Version 3 includes 108 chemicals. 2. Chemical Property Data - The source of chemical data used in the calculation is primarily EPA’s Superfund Chemical Data Matrix (SCDM) database. EPA’s WATER9 database is used for chemicals not included in the SCDM database. Appendix B contains other data sources. 3. Toxicity Values – EPA’s Integrated Risk Information System (IRIS) is the generally preferred source of carcinogenic unit risks and non-carcinogenic reference concentrations (RfCs) for inhalation exposure.1 The following two sources were consulted, in order of preference, when IRIS values were not available: provisional toxicity values recommended by EPA’s National Center for Environmental Assessment (NCEA) and EPA’s Health Effects Assessment Summary Tables (HEAST). If no inhalation toxicity data could be obtained from IRIS, NCEA, or HEAST, extrapolated unit risks and/or RfCs using toxicity data for oral exposure (cancer slope factors and/or reference doses, respectively) from these same sources 1 U.S. EPA. 2002. Integrated Risk Information System (IRIS). http://www.epa.gov/iriswebp/iris/index.html. November. viii using the same preference order were used.2 Note that for most compounds, extrapolation from oral data introduces considerable uncertainty into the resulting inhalation value. Values obtained from inhalation studies or from pharmacokinetic modeling applied to oral doses will be less uncertain than those calculated using the equations noted in footnote 2. IRIS currently does not include carcinogenicity data for trichloroethylene (TCE), a volatile contaminant frequently encountered at hazardous waste sites. The original carcinogenicity assessment for TCE, which was based on a health risk assessment conducted in the late 1980’s, was withdrawn from IRIS in 1994. The Superfund Technical Support Center has continued to recommend use of the cancer slope factor from the withdrawn assessment, until a reassessment of the carcinogenicity of TCE is completed. In 2001, the Agency published a draft of the TCE toxicity assessment for public comment.3 Using this guidance, TCE target concentrations for the draft vapor intrusion guidance were calculated using a cancer slope factor identified in that document, which is available on the NCEA web site. This slope factor was selected because it is based on state-of-the-art methodology. However, because this document is still undergoing review, the slope factor and the target concentrations calculated for TCE are subject to change and should be considered “provisional” values. Toxicity databases such as IRIS are routinely updated as new information becomes available; the data included in the lookup tables are current as of November 2002. Users of these models are strongly encouraged to research the latest toxicity values for contaminants of interest from the sources noted above. In the next year, IRIS reassessments are expected for several contaminants commonly found in subsurface contamination whose inhalation toxicity values are currently based on extrapolation. 4. Assumption and Limitations The Johnson and Ettinger (J&E) Model was developed for use as a screening level model and, consequently, is based on a number of simplifying assumptions regarding contaminant distribution and occurrence, subsurface characteristics, transport mechanisms, and building construction. The assumptions of the J&E Model as implemented in EPA’s spreadsheet version are listed in Section 2.11, Section 5, and 2 The oral-to-inhalation extrapolations assume an adult inhalation rate (IR) of 20 m3/day and an adult body weight (BW) of 70 kg. Unit risks (URs) were extrapolated from cancer slope factors (CSFs) using the following equation: UR (µg/m3)-1 = CSF (mg/kg/d)-1 * IR (m3/d) * (1/BW)(kg-1 )* (10-3 mg/µg) Reference concentrations (RfCs) were extrapolated from reference doses (RfDs) using the following equation: RfC (mg/m3) = RfD (mg/kg/d) * (1/IR) (m3/d)-1 ( BW (kg) 3 US EPA, Trichloroethylene Health Risk Assessment: Synthesis and Characterization – External Review Draft, Office of Research and Development, EPA/600/P-01-002A, August, 2001. ix Table 12 along with an assessment of the likelihood that the assumptions can be verified through field evaluation. 5. Soil Parameters A list of generally reasonable, yet conservative, model input parameters for selected soil and sampling related parameters are provided in Tables 7 and 8. These tables also provide the practical range, typical or mean value (if applicable), and most conservative value for these parameters. For building parameters with low uncertainty and sensitivity, only a single “fixed” value corresponding to the mean or typical value is provided in Table 9. Soil-dependent properties are provided in Table 10 for soils classified according to the US Soil Conservation Soil (SCS) system. If site soils are not classified according to the US SCS, Table 11 can be used to assist in selecting an appropriate SCS soil type corresponding to the available site lithologic information. Note that the selection of the soil texture class should be biased towards the coarsest soil type of significance, as determined by the site characterization program. These input parameters were developed considering soil-physics science, available studies of building characteristics, and expert opinion. Consequently, the input parameters listed in Tables 7 and 8 are considered default parameters for a first- tier assessment, which should in most cases provide a reasonably (but not overly) conservative estimate of the vapor intrusion attenuation factor for a site. 6. Building Parameters Building Air Exchange Rate (Default Value = 0.25 hr-1) Results from 22 studies for which building air exchange data are available were summarized in Hers et al. (2001). When all the data were analyzed, the 10th, 50th, and 90th percentile values were 0.21, 0.51, and 1.48 air exchanges per hour (AEH). Air exchange rates varied depending on season and climatic region. For example, for the winter season and coldest climatic area (Region 1, Great Lakes area and extreme northeast US), the 10th, 50th, and 90th percentile values were 0.11, 0.27, and 0.71 AEH. In contrast, for the winter season and warmest climatic area [Region 4 (southern California, Texas, Florida, Georgia)], the 10th, 50th, and 90th percentile values were 0.24, 0.48, and 1.13 AEH. For this guidance, a default value of 0.25 for air exchange rate was selected to represent the lower end of these distributions. The previous version of the guidance included a default value of 0.45 exchanges per hour. Building Area and Subsurface Foundation Area (Default Value = 10 m by 10 m) A Michigan study indicates that a 111.5 m2 area approximately corresponds to the 10th percentile floor space area for residential single family dwellings, based on x statistics compiled by the U.S. Department of Commerce (DOC) and U.S. Housing and Urban Development (HUD). The previous median value was 9.61 m x 9.61 m. Building Mixing Height (Default Value = 2.44 m for slab-on-grade scenario; = 3.66 m for basement scenario) The J&E Model assumes that subsurface volatiles migrating into the building are completely mixed within the building volume, which is determined by the building area and mixing height. The building mixing height will depend on a number of factors including the building height, the heating, ventilation and air conditioning (HVAC) system operation, environmental factors such as indoor-outdoor pressure differentials and wind loading, and seasonal factors. For a single-story house, the variation in mixing height can be approximated by the room height. For a multi-story house or apartment building, the mixing height will be greatest for houses with HVAC systems that result in significant air circulation (e.g., forced-air heating systems). Mixing heights will be less for houses using electrical baseboard heaters. It is likely that mixing height is, to some degree, correlated to the building air exchange rate. There are little data available that provide for direct inference of mixing height. There are few sites, with a small number of houses where indoor air concentrations were above background, and where both measurements at ground level and the second floor were made (CDOT, Redfields, Eau Claire). Persons familiar with the data sets for these sites indicate that in most cases a fairly significant reduction in concentrations (factor of two or greater) was observed, although at one site (Eau Claire, "S” residence), the indoor TCE concentrations were similar in both the basement and second floor of the house. For the CDOT site apartments, there was an approximate five-fold reduction between the concentrations measured for the first floor and second floor units. Less mixing would be expected for an apartment because there are less cross-floor connections than for a house. The default value chosen for a basement house scenario (3.66 m) would be representative of a two-fold reduction or attenuation in vapor concentrations between floors. Crack Width (0.1 cm) and Crack Ratio (Default Value = 0.0002 for basement house; = 0.0038 for slab-on-grade house) The crack width and crack ratio are related. Assuming a square house and that the only crack is a continuous edge crack between the foundation slab and wall (“perimeter crack”), the crack ratio and crack width are related as follows: CrackRatio = SubsurfaceFoundationArea Area Foundation SubsurfaceWidth Crack / (4 xi There is little information available on crack width or crack ratio. One approach used by radon researchers is to back calculate crack ratios using a model for soil gas flow through cracks and the results of measured soil gas flow rates into a building. For example, the back-calculated values for a slab/wall edge crack based on soil gas-entry rates reported in Nazaroff (1992), Revzan et al. (1991), and Nazaroff et al. (1985) range from approximately 0.0001 to 0.001. Another possible approach is to measure crack openings although this, in practice, is difficult to do. Figley and Snodgrass (1992) present data from ten houses where edge crack measurements were made. At the eight houses where cracks were observed, the cracks’ widths ranged from hairline cracks up to 5 mm wide, while the total crack length per house ranged from 2.5 m to 17.3 m. Most crack widths were less than 1 mm. The suggested defaults for crack ratio is regulatory guidance, literature and models also vary. In ASTM E1739-95, a default crack ratio of 0.01 is used. The crack ratios suggested in the VOLASOIL model (developed by the Dutch Ministry of Environment) range from 0.0001 to 0.0000001. The VOLASOIL model values correspond to values for a “good” and “bad” foundation, respectively. The crack ratio used by J&E (1991) for illustrative purposes ranged from 0.001 to 0.01. The selected default values fall within the ranges observed. Qsoil (Default Value = 5 L/min) The method used to estimate the vapor flowrate into a building (Qsoil) is an analytical solution for two-dimensional soil gas flow to a small horizontal drain (Nazaroff 1992) (“Perimeter Crack Model”). Use of this model can be problematic in that Qsoil values are sensitive to soil-air permeability and consequently a wide range in flows can be predicted. An alternate empirical approach was selected to determine the Qsoil value. This new approach is based on trace tests (i.e., mass balance approach). When soil gas advection is the primary mechanism for tracer intrusion into a building, the Qsoil value is estimated by measuring the concentrations of a chemical tracer in indoor air, outdoor air, and in soil vapor below a building, and measuring the building ventilation rate (Hers et al. 2000a; Fischer et al. 1996; Garbesi et al. 1993; Rezvan et al. 1991; Barbesi and Sectro 1989). The Qsoil values measured using this technique were compared to predicted rates using the Perimeter Crack model, for sites with coarse-grained soils. The Perimeter Crack model predictions are both higher and lower than the measured values, but overall are within one order of magnitude of the measured values. Although the Qsoil predicted by the models and measured using field tracer tests are uncertain, the results suggest that a “typical” range for houses on coarse-grained soils is on the order of 1 to 10 L/min. A disadvantage with the tracer test approach is that there are only limited data, and there do not appear to be any tracer studies for field sites with fine-grained soils. xii Because the advective flow zone is relatively limited in extent, the soil type adjacent to the building foundation is of importance. In many cases, coarse-grained imported fill is placed below foundations, and either coarse-grained fill, or disturbed, loose fill is placed adjacent to the foundation walls. Therefore, a conservative approach for the purposes of this guidance is to assume that soil gas flow will be controlled by coarse-grained soil, and not to rely on the possible reduction in flow that would be caused by fine-grained soils near the house foundation. For these reasons, a soil gas flow rate of 5 L/min (midpoint between 1 and 10 L/min) was chosen as the input value. 7. Convenience Changes • Default values for soil bulk densities have been added to the lookup tables for the various soil types. • Default values for soil water-filled porosity have been updated within the lookup tables for soil properties for the various soil types. • The chemical data list has been expanded to include 108 chemicals. Chemical physical properties were reviewed and updated where applicable to provide the user with more accurate values. • All of the lookup functions within the models were modified to include an exact match parameter, rather than a closest match. The models would previously return data for CAS Numbers not in the lookup tables. Although the DATENTER sheet informed the user that this CAS Number was not found, it would return values on the CHEMPROPS sheet that was the closest match. This caused some confusion and therefore was changed. • CAS number and soil type pick lists were added to the cells within the models where the user is required to provide data in a specific format. The pick lists were added to assist the user from entering data that are not an acceptable parameter. • All models were modified to require the user to specify the soil type of each stratum. In addition, a button was added that allows the user to automatically retrieve the default values for the soil type selected. These additions were added as a convenience to the user and soil selection can be ignored should site-specific data be available. • All models were modified to include an input for the average vapor flow rate into the building (Qsoil) in liters/minute (L/min). This value can be left blank and the model will calculate the value of Qsoil as was done in previous versions. • All models were also modified to include a button that will reset the default value on the DATENTER sheet. This button will allow the user to clear all values and reset the default values or reset only those values that have a default value. The user is also allowed to specify whether the values should be reset for the basement or slab-on-grade scenario. xiii SECTION 1 INTRODUCTION TO THE VAPOR INTRUSION MODEL THEORY AND APPLICATION Volatilization of contaminants located in subsurface soils or in groundwater, and the subsequent mass transport of these vapors into indoor spaces constitutes a potential inhalation exposure pathway, which may need to be evaluated when preparing risk assessments. Likewise, this potential indoor inhalation exposure pathway may need evaluation when estimating a risk-based soil or groundwater concentration below which associated adverse health effects are unlikely. Johnson and Ettinger (J&E) (1991) introduced a screening-level model that incorporates both convective and diffusive mechanisms for estimating the transport of contaminant vapors emanating from either subsurface soils or groundwater into indoor spaces located directly above the source of contamination. In their article, J&E reported that the results of the model were in qualitative agreement with published experimental case histories and in good qualitative and quantitative agreement with detailed three-dimensional numerical modeling of radon transport into houses. The J&E Model is a one-dimensional analytical solution to convective and diffusive vapor transport into indoor spaces and provides an estimated attenuation coefficient that relates the vapor concentration in the indoor space to the vapor concentration at the source of contamination. The model is constructed as both a steady-state solution to vapor transport (infinite or non-diminishing source) and as a quasi-steady-state solution (finite or diminishing source). Inputs to the model include chemical properties of the contaminant, saturated and unsaturated zone soil properties, and structural properties of the building. This manual provides documentation and instructions for using the vapor intrusion model as provided in the accompanying spreadsheets. Model results (both screening and advanced) are provided as either a risk-based soil or groundwater concentration, or as an estimate of the actual incremental risks associated with a user- defined initial concentration. That is to say that the model will reverse-calculate an “acceptable” soil or groundwater concentration given a user-defined risk level (i.e., target risk level or target hazard quotient), or the model may be used to forward-calculate an incremental cancer risk or hazard quotient based on an initial soil or groundwater concentration. The infinite source models for soil contamination and groundwater contamination should be used as first-tier screening tools. In these models, all but the most sensitive model parameters have 1 been set equal to central tendency or upper bound values. Values for the most sensitive parameters may be user-defined. More rigorous estimates may be obtained using site-specific data and the finite source model for soil contamination. Because the source of groundwater contamination may be located upgradient of the enclosed structure for which the indoor inhalation pathway is to be assessed, the advanced model for contaminated groundwater is based on an infinite source of contamination, however, site- specific values for all other model parameters may be user-defined. In addition to the finite and infinite source models referred to above, two models that allow the user to input empirical soil gas concentration and sampling depth information directly into the spreadsheets. These models will subsequently estimate the resulting steady-state indoor air concentrations and associated health risks. Because of the paucity of empirical data available for either bench-scale or field-scale verification of the accuracy of these models, as well as for other vapor intrusion models, the user is advised to consider the variation in input parameters and to explore and quantify the impacts of assumptions on the uncertainty of model results. At a minimum, a range of results should be generated based on variation of the most sensitive model parameters. 2 SECTION 2 MODEL THEORY Chemical fate and transport within soils and between the soil column and enclosed spaces are determined by a number of physical and chemical processes. This section presents the theoretical framework on which the J&E Model is based, taking into account the most significant of these processes. In addition, this section also presents the theoretical basis for estimating values for some of the most sensitive model parameters when empirical field data are lacking. The fundamental theoretical development of this model was performed by J&E (1991). 2.1 MODEL SETTING Consider a contaminant vapor source (Csource) located some distance (LT) below the floor of an enclosed building constructed with a basement or constructed slab-on-grade. The source of contamination is either a soil-incorporated volatile contaminant or a volatile contaminant in solution with groundwater below the top of the water table. Figure 1 is a simplified conceptual diagram of the scenario where the source of contamination is incorporated in soil and buried some distance below the enclosed space floor. At the top boundary of contamination, molecular diffusion moves the volatilized contaminant toward the soil surface until it reaches the zone of influence of the building. Here convective air movement within the soil column transports the vapors through cracks between the foundation and the basement slab floor. This convective sweep effect is induced by a negative pressure within the structure caused by a combination of wind effects and stack effects due to building heating and mechanical ventilation. Figure 2 illustrates the scenario where the source of contamination is below the top of the water table. Here the contaminant must diffuse through a capillary zone immediately above the water table and through the subsequent unsaturated or vadose zone before convection transports the vapors into the structure. The suggested minimum site characterization information for a first-tier evaluation of the vapor intrusion pathway includes: site conceptual model, nature and extent of contamination distribution, soil lithologic descriptions, groundwater concentrations, and/or possibly near source soil vapor concentrations. The number of samples and measurements needed to establish this information varies by site, and it is not possible to provide a hard and fast rule. 3 Figure 1. Pathway for Subsurface Vapor Intrusion into Indoor Air 4 Figure 2. Vapor Pathway into Buildings 5 Based on the conceptual site model, the user can select the appropriate spreadsheet corresponding to the vapor source at the site and determine whether to use the screening level spreadsheet (which accommodates only one soil type above the capillary fringe) or the more advanced version (which allows up to three layers above the capillary fringe). As most of the inputs to the J&E Model are not collected during a typical site characterization, conservative inputs are typically estimated or inferred from available data and other non-site specific sources of information. Table 1 lists 114 chemicals that may be found at hazardous waste sites and it indicates whether the chemical is sufficiently toxic and volatile to result in a potentially unacceptable indoor inhalation risk. It also provides a column for checking off the chemicals found or reasonably suspected to be present in the subsurface at a site. Under this approach, a chemical is considered sufficiently toxic if the vapor concentration of the pure component poses an incremental lifetime cancer risk greater than 10-6 or results in a non-cancer hazard index greater than one. A chemical is considered sufficiently volatile if its Henry’s Law Constant is 1 x 10 -5 atm-m3/mol or greater (EPA, 1991). It is assumed that if a chemical does not meet both of these criteria, it need not be further considered as part of the evaluation. Table 1 also identifies six chemicals that meet the toxicity and volatility criteria but are not included in the vapor intrusion models because one or more of the needed physical or chemical properties has not been found in the literature. The rate of soil gas entry (Qsoil) or average vapor flow rate into the building is a function solely of convection; however, the vapor concentration entering the structure may be limited by either convection or diffusion depending upon the magnitude of the source-building separation (LT). 2.2 VAPOR CONCENTRATION AT THE SOURCE OF CONTAMAINATION With a general concept of the problem under consideration, the solution begins with an estimate of the vapor concentration at the source of contamination. In the case of soil contamination, the initial concentration (CR) does not contain a residual- phase (e.g., nonaqueous-phase liquid or solid); and in the case of contaminated groundwater, the initial contaminant concentration (CW) is less than the aqueous solubility limit (i.e., in solution with water). Given these initial conditions, Csource for soil contamination may be estimated from Johnson et al. (1990) as: H ′ TS C R ρbC = source θw + K d ρb + H ′ (1) TS θ a where Csource = Vapor concentration at the source of contamination, g/cm3-v H'TS = Henry's law constant at the system (soil) temperature, dimensionless 6 TABLE 1. SCREENING LIST OF CHEMICALS CAS No. Chemical Is Chemical Sufficiently Toxic?1 Is Chemical Sufficiently Volatile?2 Check Here if Known or Reasonably Suspected to be Present 3 83329 Acenaphthene YES YES 75070 Acetaldehyde YES YES 67641 Acetone YES YES 75058 Acetronitrile YES YES 98862 Acetophenone YES YES 107028 Acrolein YES YES 107131 Acrylonitrile YES YES 309002 Aldrin YES YES 319846 Alpha-HCH (alpha-BHC) YES YES 62533 Aniline YES NO NA 120127 Anthracene NO YES NA 56553 Benz(a)anthracene YES NO NA 100527 Benzaldehyde YES YES 71432 Benzene YES YES 50328 Benzo(a)pyrene YES NO NA 205992 Benzo(b)fluoranthene YES YES 207089 Benzo(k)fluoranthene NO NO NA 65850 Benzoic Acid NO NO NA 100516 Benzyl alcohol YES NO NA 100447 Benzylchloride YES YES 91587 Beta-Chloronaphthalene 3 YES YES 319857 Beta-HCH(beta-BHC) YES NO NA 92524 Biphenyl YES YES 111444 Bis(2-chloroethyl)ether YES YES 108601 Bis(2-chloroisopropyl)ether 3 YES YES 117817 Bis(2-ethylhexyl)phthalate NO NO NA 542881 Bis(chloromethyl)ether 3 YES YES 75274 Bromodichloromethane YES YES 75252 Bromoform YES YES 106990 1,3-Butadiene YES YES 71363 Butanol YES NO NA 85687 Butyl benzyl phthalate NO NO NA 86748 Carbazole YES NO NA 75150 Carbon disulfide YES YES 56235 Carbon tetrachloride YES YES 57749 Chlordane YES YES (continued) 7 CAS No. Chemical Is Chemical Sufficiently Toxic?1 Is Chemical Sufficiently Volatile?2 Check Here if Known or Reasonably Suspected to be Present 3 126998 2-Chloro-1,3-butadiene(chloroprene) YES YES 108907 Chlorobenzend YES YES 109693 1-Chlorobutane YES YES 124481 Chlorodibromomethane YES YES 75456 Chlorodifluoromethane YES YES 75003 Chloroethane (ethyl chloride) YES YES 67663 Chloroform YES YES 95578 2-Chlorophenol YES YES 75296 2-Chloropropane YES YES 218019 Chrysene YES YES 156592 Cis-1,2-Dichloroethylene YES YES 123739 Crotonaldehyde(2-butenal) YES YES 998828 Cumene YES YES 72548 DDD YES NO NA 72559 DDE YES YES 50293 DDT YES NO NA 53703 Dibenz(a,h)anthracene YES NO NA 132649 Dibenzofuran YES YES 96128 1,2-Dibromo-3-chloropropane 3 YES YES 106934 1,2-Dibromoethane(ethylene dibromide) YES YES 541731 1,3-Dichlorobenzene YES YES 95501 1,2-Dichlorobenzene YES YES 106467 1,4-Dichlorobenzene YES YES 91941 3,3-Dichlorobenzidine YES NO NA 75718 Dichlorodifluoromethane YES YES 75343 1,1-Dichloroethane YES YES 107062 1,2-dichloroethane YES YES 75354 1,1-Dichloroethylene YES YES 120832 2,4-Dichloroephenol YES NO NA 78875 1,2-Dichloropropane YES YES 542756 1,3-Dichloropropene YES YES 60571 Dieldrin YES YES 84662 Diethylphthalate YES NO NA 105679 2,4-Dimethylphenol YES NO NA 131113 Dimethylphthalate NA NO NA 84742 Di-n-butyl phthalate NO NO NA (continued) 8 CAS No. Chemical Is Chemical Sufficiently Toxic?1 Is Chemical Sufficiently Volatile?2 Check Here if Known or Reasonably Suspected to be Present 3 534521 4,6 Dinitro-2methylphenol (4, 6-dinitro-o- cresol) YES NO NA 51285 2,4-Dinitrophenol YES NO NA 121142 2,4-Dinitrotoluene YES NO NA 606202 2,6-Dinitrotoluene YES NO NA 117840 Di-n-octyl phthalate NO YES NA 115297 Endosulfan YES YES 72208 Endrin YES NO NA 106898 Epichlorohydrin 3 YES YES 60297 Ethyl ether YES YES 141786 Ethylacetate YES YES 100414 Ethylbenzene YES YES 75218 Ethylene oxide YES YES 97632 Ethylmethacrylate YES YES 206440 Fluoranthene NO YES NA 86737 Fluorene YES YES 110009 Furane YES YES 58899 Gamma-HCH(Lindane) YES YES 76448 Heptachlor YES YES 1024573 Heptachlor epoxide YES NO NA 87683 Hexachloro-1,3-butadiene YES YES 118741 Hexachlorobenzene YES YES 77474 Hexachlorocyclopentadiene YES YES 67721 Hexachloroethane YES YES 110543 Hexane YES YES 74908 Hydrogene cyanide YES YES 193395 Indeno (1,2,3-cd)pyrene NO NO NA 78831 Isobutanol YES YES 78591 Isophorone YES NO NA 7439976 Mercury (elemental) YES YES 126987 Methacrylonitrile YES YES 72435 Methoxychlor YES YES 79209 Methy acetate YES YES 96333 Methyl acrylate YES YES 74839 Methyl bromide YES YES 74873 Methyl chloride (chloromethane) YES YES 108872 Methylcyclohexane YES YES (continued) 9 CAS No. Chemical Is Chemical Sufficiently Toxic?1 Is Chemical Sufficiently Volatile?2 Check Here if Known or Reasonably Suspected to be Present 3 74953 Methylene bromide YES YES 75092 Methylene chloride YES YES 78933 Methylethylketone (2-butanone) YES YES 108101 Methylisobutylketone (4-methyl-2- pentanone) YES YES 80626 Methylmethacrylate YES YES 91576 2-Methylnaphthalene YES YES 108394 3-Methylphenol(m-cresol) YES NO NA 95487 2-Methylphenol(o-cresol) YES NO NA 106455 4-Methylphenol (p-cresol) YES NO NA 99081 m-Nitrotoluene YES NO NA 1634044 MTBE YES YES 108383 m-Xylene YES YES 91203 Naphthalene YES YES 104518 n-Butylbenzene YES YES 98953 Nitrobenzene YES YES 100027 4-Nitrophenol YES NO NA 79469 2-Nitropropane YES YES 924163 N-nitroso-di-n-butylamine 3 YES YES 621647 N-Nitroso-di-n-propylamine YES NO NA 86306 N-Nitrosodiphenylamine YES NO NA 103651 n-Propylbenzene YES YES 88722 o-Nitrotoluene YES YES 95476 o-Xylene YES YES 106478 p-Chloroaniline YES NO NA 87865 Pentachlorophenol YES NO NA 108952 Phenol YES NO NA 99990 p-Nitrotoluene YES NO NA 106423 p-Xylene YES YES 129000 Pyrene YES YES 110861 Pyridine YES NO NA 135988 Sec-Butylbenzene YES YES 100425 Styrene YES YES 98066 Tert-Butylbenzene YES YES 630206 1,1,1,2-Tetrachloroethane YES YES 79345 1,1,2,2,-Tetrachloroethane YES YES 127184 Tetrachloroethylene YES YES (continued) 10 CAS No. Chemical Is Chemical Sufficiently Toxic?1 Is Chemical Sufficiently Volatile?2 Check Here if Known or Reasonably Suspected to be Present 3 108883 Toluene YES YES 8001352 Toxaphen YES NO NA 156605 Trans-1,2-Dichloroethylene YES YES 76131 1,1,2-Trichloro-1,2,2-trifluoroethane YES YES 120821 1,2,4-Trichlorobenzene YES YES 79005 1,1,2-Trichloroethane YES YES 71556 1,1,1-Trichloroethane YES YES 79016 Trichloroethylene YES YES 75694 Trichlorofluoromethane YES YES 95954 2,4,5-Trichlorophenol YES NO NA 88062 2,4,6-Trichlorophenol YES NO NA 96184 1,2,3-Trichloropropane YES YES 95636 1,2,4-Trimethylbenzene YES YES 108678 1,3,5-Trimethylbenzene YES YES 108054 Vinyl acetate YES YES 75014 Vinyl chloride (chloroethene) YES YES 1 A chemical is considered sufficiently toxic if the vapor concentration of the pure component poses an incremental lifetime cancer risk greater than 10-6 or a non-cancer hazard index greater than 1. 2 A chemical is considered sufficiently volatile if its Henry’s law constant is 1 x 10-5 atm-m3/mol or greater. 3 One or more of the physical chemical properties required to run the indoor air vapor intrusion models was not found during a literature search conducted March 2003. 11 CR = Initial soil concentration, g/g Db = Soil dry bulk density, g/cm3 2w = Soil water-filled porosity, cm3/cm3 Kd = Soil-water partition coefficient, cm3/g (= Koc x foc) 2a = Soil air-filled porosity, cm3/cm3 Koc = Soil organic carbon partition coefficient, cm3/g foc = Soil organic carbon weight fraction. If the initial soil concentration includes a residual phase, the user is referred to the NAPL­ SCREEN or NAPL-ADV models as discussed in Appendix A. These models estimate indoor air concentrations and associated risks for up to 10 user-defined contaminants that comprise a residual phase mixture in soils. Csource for groundwater contamination is estimated assuming that the vapor and aqueous- phases are in local equilibrium according to Henry's law such that: C = H ′ source TSCw (2) where Csource = Vapor concentration at the source of contamination, g/cm3-v H'TS = Henry's law constant at the system (groundwater) temperature, dimensionless Cw = Groundwater concentration, g/cm3-w. The dimensionless form of the Henry's law constant at the system temperature (i.e., at the average soil/groundwater temperature) may be estimated using the Clapeyron equation by: H ′= exp    −∆H R v c ,TS   T 1 S − T 1 R      H R (3)TS RTS where H'TS = Henry's law constant at the system temperature, dimensionless )Hv,TS = Enthalpy of vaporization at the system temperature, cal/mol 12 TS = System temperature, °K TR = Henry's law constant reference temperature, oK HR = Henry's law constant at the reference temperature, atm-m3/mol RC = Gas constant (= 1.9872 cal/mol -oK) R = Gas constant (= 8.205 E-05 atm-m3/mol-oK). The enthalpy of vaporization at the system temperature can be calculated from Lyman et al. (1990) as: n (1 − TS / TC )∆Hv,TS =∆Hv,b  (1 − TB / TC ) (4) where )Hv,TS = Enthalpy of vaporization at the system temperature, cal/mol )Hv,b = Enthalpy of vaporization at the normal boiling point, cal/mol TS = System temperature, oK TC = Critical temperature, oK TB = Normal boiling point, oK n = Constant, unitless. Table 2 gives the value of n as a function of the ratio TB/TC. TABLE 2. VALUES OF EXPONENT n AS A FUNCTION OF TB/TC TB/TC N < 0.57 0.30 0.57 - 0.71 0.74 (TB/TC) - 0.116 > 0.71 0.41 13 2.3 DIFFUSION THROUGH THE CAPILLARY ZONE Directly above the water table, a saturated capillary zone exists whereby groundwater is held within the soil pores at less than atmospheric pressure (Freeze and Cherry, 1979). Between drainage and wetting conditions, the saturated water content varies but is always less than the fully saturated water content which is equal to the soil total porosity. This is the result of air entrapment in the pores during the wetting process (Gillham, 1984). Upon rewetting, the air content of the capillary zone will be higher than after main drainage. Therefore, the air content will vary as a function of groundwater recharge and discharge. At the saturated water content, Freijer (1994) found that the relative vapor-phase diffusion coefficient was almost zero. This implies that all remaining air-filled soil pores are disconnected and thus blocked for gas diffusion. As the air-filled porosity increased, however, the relative diffusion coefficient indicated the presence of connected air-filled pores that corresponded to the air-entry pressure head. The air-entry pressure head corresponds with the top of the saturated capillary zone. Therefore, to allow for the calculation of the effective diffusion coefficient by lumping the gas-phase and aqueous-phase together, the water-filled soil porosity in the capillary zone (2w,cz) is calculated at the air-entry pressure head (h) according to the procedures of Waitz et al. (1996) and the van Genuchten equation (van Genuchten, 1980) for the water retention curve: θ −θsrθw,cz =θr +[1 + (α1h)N ]M (5) where 2w,cz = Water-filled porosity in the capillary zone, cm3/cm3 2r = Residual soil water content, cm3/cm3 2s = Saturated soil water content, cm3/cm3 " 1 = Point of inflection in the water retention curve where d θw/dh is maximal, cm-1 h = Air-entry pressure head, cm (= 1/" 1 and assumed to be positive) N = van Genuchten curve shape parameter, dimensionless M = 1 - (1/N). With a calculated value of 2w,cz within the capillary zone at the air-entry pressure head, the air-filled porosity within the capillary zone (2a,cz) corresponding to the minimum value at which gas diffusion is relevant is calculated as the total porosity (n) minus 2w,cz. Hers (2002) computed the SCS class average values of the water filled porosity and the height of the capillary zone SCS soil textural classifications. Table 3 provides the class average values for each of the SCS soil types. These data replace the mean values developed by Schaap and 14 Leij (1998) included in the previous U.S. Environmental Protection Agency (EPA) version of the J&E Models. With the class average values presented in Table 3, a general estimate can be made of the values of 2w,cz and 2a,cz for each soil textural classification. The total concentration effective diffusion coefficient across the capillary zone (Dczeff) may then be calculated using the Millington and Quirk (1961) model as: 3.33 2D eff 3.33 2 TS )(θw,cz / ncz ) (6)cz = Da (θa,cz / ncz )+ (Dw / H ′ where Dczeff = Effective diffusion coefficient across the capillary zone, cm2/s Da = Diffusivity in air, cm2/s 2a,cz = Soil air-filled porosity in the capillary zone, cm3/cm3 ncz = Soil total porosity in the capillary zone, cm3/cm3 Dw = Diffusivity in water, cm2/s H'TS = Henry's law constant at the system temperature, dimensionless 2w,cz = Soil water-filled porosity in the capillary zone, cm3/cm3. According to Fick's law of diffusion, the rate of mass transfer across the capillary zone can be approximated by the expression: effE = A(Csource − Cg 0 )Dcz / Lcz (7) where E = Rate of mass transfer, g/s A = Cross-sectional area through which vapors pass, cm2 Csource = Vapor concentration within the capillary zone, g/cm3-v Cg0 = A known vapor concentration at the top of the capillary zone, g/cm3-v (Cg0 is assumed to be zero as diffusion proceeds upward) Dczeff = Effective diffusion coefficient across the capillary zone, cm2/s Lcz = Thickness of capillary zone, cm. 15 TABLE 3. CLASS AVERAGE VALUES OF THE VAN GENUCHTEN SOIL WATER RETENTION PARAMETERS FOR THE 12 SCS SOIL TEXTURAL CLASSIFICATIONS van Genuchten parameters Soil texture (USDA) Saturated water content, 2s Residual water Content, 2r " 1 (1/cm) N M Clay 0.459 0.098 0.01496 1.253 0.2019 Clay loam 0.442 0.079 0.01581 1.416 0.2938 Loam 0.399 0.061 0.01112 1.472 0.3207 Loamy sand 0.390 0.049 0.03475 1.746 0.4273 Silt 0.489 0.050 0.00658 1.679 0.4044 Silty loam 0.439 0.065 0.00506 1.663 0.3987 Silty clay 0.481 0.111 0.01622 1.321 0.2430 Silty clay loam 0.482 0.090 0.00839 1.521 0.3425 Sand 0.375 0.053 0.03524 3.177 0.6852 Sandy clay 0.385 0.117 0.03342 1.208 0.1722 Sandy clay loam 0.384 0.063 0.02109 1.330 0.2481 Sandy loam 0.387 0.039 0.02667 1.449 0.3099 16 R The value of Csource is calculated using Equation 2; the value of A is assumed to be 1 cm2; and the value of Dczeff is calculated by Equation 6. What remains is a way to estimate a value for Lcz. Lohman (1972) and Fetter (1994) estimated the rise of the capillary zone above the water table using the phenomenon of capillary such that water molecules are subject to an upward attractive force due to surface tension at the air-water interface and the molecular attraction of the liquid and solid phases. The rise of the capillary zone can thus be estimated using the equation for the height of capillary rise in a bundle of tubes of various diameters equivalent to the diameters between varying soil grain sizes. Fetter (1994) estimated the mean rise of the capillary zone as: 2 α COS λ ρw g R where Lcz = Mean rise of the capillary zone, cm α2 = Surface tension of water, g/s (= 73) 8 = Angle of the water meniscus with the capillary tube, degrees (assumed to be zero) Dw = Density of water, g/cm3 (= 0.999) g = Acceleration due to gravity, cm/s2 (= 980) R = Mean interparticle pore radius, cm Lcz = 2 (8) and; R = 0.2D (9) where R = Mean interparticle pore radius, cm D = Mean particle diameter, cm. Assuming that the default values of the parameters given in Equation 8 are for groundwater between 5o and 25oC, Equation 8 reduces to: 0.15Lcz = . (10) Nielson and Rogers (1990) estimated the arithmetic mean particle diameter for each of the 12 SCS soil textural classifications at the mathematical centroid calculated from its classification area (Figure 3). Table 4 shows the centroid compositions and mean particle sizes of the 12 SCS soil textural classes. 17 Figure 3. U.S. Soil Conservation Service Classification Chart Showing Centroid Compositions (Solid Circles) 18 TABLE 4. CENTROID COMPOSITIONS, MEAN PARTICLE DIAMETERS AND DRY BULK DENSITY OF THE 12 SCS SOIL TEXTURAL CLASSIFICATIONS Textural class % clay % silt % sand Arithmetic mean particle diameter, cm Dry Bulk Density g/cm3 Sand 3.33 5.00 91.67 0.044 1.66 Loamy sand 6.25 11.25 82.50 0.040 1.62 Sandy loam 10.81 27.22 61.97 0.030 1.62 Sandy clay loam 26.73 12.56 60.71 0.029 1.63 Sandy clay 41.67 6.67 51.66 0.025 1.63 Loam 18.83 41.01 40.16 0.020 1.59 Clay loam 33.50 34.00 32.50 0.016 1.48 Silt loam 12.57 65.69 21.74 0.011 1.49 Clay 64.83 16.55 18.62 0.0092 1.43 Silty clay loam 33.50 56.50 10.00 0.0056 1.63 Silt 6.00 87.00 7.00 0.0046 1.35 Silty clay 46.67 46.67 6.66 0.0039 1.38 Given the mean particle diameter data in Table 4, the mean thickness of the capillary zone may then be estimated using Equations 9 and 10. 2.4 DIFFUSION THROUGH THE UNSATURATED ZONE The effective diffusion coefficient within the unsaturated zone may also be estimated using the same form as Equation 6: Di eff = Da (θ a 3 , . i 33 / ni 2 )+ (Dw / H ′ 3.33 2 TS )(θw,i / ni ) (11) 19 where Dieff = Effective diffusion coefficient across soil layer i, cm2/s Da = Diffusivity in air, cm2/s 2a,i = Soil air-filled porosity of layer i, cm3/cm3 ni = Soil total porosity of layer i, cm3/cm3 Dw = Diffusivity in water, cm2/s 2w,i = Soil water-filled porosity of layer i, cm3/cm3 H'TS = Henry's law constant at the system temperature, dimensionless The overall effective diffusion coefficient for systems composed of n distinct soil layers between the source of contamination and the enclosed space floor is: DT eff = n LT (12) eff∑ Li / Di i =0 where DTeff = Total overall effective diffusion coefficient, cm2/s Li = Thickness of soil layer i, cm Dieff = Effective diffusion coefficient across soil layer i, cm2/s LT = Distance between the source of contamination and the bottom of the enclosed space floor, cm. Note that in the case of cracks in the floor of the enclosed space, the value of LT does not include the thickness of the floor, nor does the denominator of Equation 12 include the thickness of the floor and the associated effective diffusion coefficient across the crack(s). An unlimited number of soil layers, including the capillary zone, may be included in Equation 12, but all layers must be located between the source of contamination and the enclosed space floor. 2.5 THE INFINITE SOURCE SOLUTION TO CONVECTIVE AND DIFFUSIVE TRANSPORT Under the assumption that mass transfer is steady-state, J&E (1991) give the solution for the attenuation coefficient (α) as: 20         DT eff AB  x exp   Qsoil Lcrack   α =  Qbuilding LT   Dcrack Acrack  (13) exp  Qsoil Lcrack  +  DT eff AB  +  DT eff AB    exp  Qsoil Lcrack  − 1       Dcrack Acrack   Qbuilding LT   Qsoil LT   Dcrack Acrack   where " = Steady-state attenuation coefficient, unitless DTeff = Total overall effective diffusion coefficient, cm2/s AB = Area of the enclosed space below grade, cm2 Qbuilding = Building ventilation rate, cm3/s LT = Source-building separation, cm Qsoil = Volumetric flow rate of soil gas into the enclosed space, cm3/s Lcrack = Enclosed space foundation or slab thickness, cm Acrack = Area of total cracks, cm2 Dcrack = Effective diffusion coefficient through the cracks, cm2/s (assumed equivalent to Dieff of soil layer i in contact with the floor). The total overall effective diffusion coefficient is calculated by Equation 12. The value of AB includes the area of the floor in contact with the underlying soil and the total wall area below grade. The building ventilation rate (Qbuilding) may be calculated as: Qbuilding =(LB WB H B ER)/3,600 s / h (14) where Qbuilding = Building ventilation rate, cm3/s LB = Length of building, cm WB = Width of building, cm HB = Height of building, cm 21 ER = Air exchange rate, (1/h). The building dimensions in Equation 14 are those dimensions representing the total "living" space of the building; this assumes that the total air volume within the structure is well mixed and that any vapor contaminant entering the structure is instantaneously and homogeneously distributed. The volumetric flow rate of soil gas entering the building (Qsoil) is calculated by the analytical solution of Nazaroff (1988) such that: 2 π∆P k Xv crackQsoil =µln (2 Zcrack / rcrack ) (15) where Qsoil = Volumetric flow rate of soil gas entering the building, cm3/s π = 3.14159 )P = Pressure differential between the soil surface and the enclosed space, g/cm-s2 kv = Soil vapor permeability, cm2 Xcrack = Floor-wall seam perimeter, cm : = Viscosity of air, g/cm-s Zcrack = Crack depth below grade, cm rcrack = Equivalent crack radius, cm. Equation 15 is an analytical solution to vapor transport solely by pressure-driven air flow to an idealized cylinder buried some distance (Zcrack) below grade; the length of the cylinder is taken to be equal to the building floor-wall seam perimeter (Xcrack). The cylinder, therefore, represents that portion of the building below grade through which vapors pass. The equivalent radius of the floor- wall seam crack (rcrack) is given in J&E (1991) as: rcrack =η (AB / Xcrack ) (16) where rcrack = Equivalent crack radius, cm 0 = Acrack/AB, (0 ≤ 0 ≤ 1) 22   AB = Area of the enclosed space below grade, cm2 Xcrack = Floor-wall seam perimeter, cm. The variable rcrack is actually the product of the fixed crack-to-total area ratio (0) and the hydraulic radius of the idealized cylinder, which is equal to the total area (AB) divided by that portion of the cylinder perimeter in contact with the soil gas (Xcrack). Therefore, if the dimensions of the enclosed space below grade (AB) and/or the floor-wall seam perimeter (Xcrack) vary, and the crack-to-total area ratio (0) remains constant, the value of rcrack must also vary. The total area of cracks (Acrack) is the product of 0 and AB. Equation 15 requires that the soil column properties within the zone of influence of the building (e.g., porosities, bulk density, etc.) be homogeneous, that the soil be isotropic with respect to vapor permeability, and that the pressure within the building be less than atmospheric. Equation 13 contains the exponent of the following dimensionless group:  Qsoil Lcrack  . (17)   crack  D Acrack  This dimensionless group represents the equivalent Peclet number for transport through the building foundation. As the value of this group approaches infinity, the value of " approaches:  eff  DT AB   Qbuilding LT  . (18)  Deff A   T B  + 1  Qsoil LT  In the accompanying spreadsheets, if the exponent of Equation 17 is too great to be calculated, the value of " is set equal to Equation 18. With a calculated value of ", the steady-state vapor-phase concentration of the contaminant in the building (Cbuilding) is calculated as: Cbuilding =α Csource . (19) 23   2.6 THE FINITE SOURCE SOLUTION TO CONVECTIVE AND DIFFUSIVE TRANSPORT If the thickness of soil contamination is known, the finite source solution of J&E (1991) can be employed such that the time-averaged attenuation coefficient (<α>) may be calculated as: 〈α〉 =ρb CR ∆H c AB  L0 T  [(β 2 + 2 Ψτ )1/2 − β] (20)Qbuilding Csource τ  ∆Hc  where <α> = Time-averaged finite source attenuation coefficient, unitless ρb = Soil dry bulk density at the source of contamination, g/cm3 CR = Initial soil concentration, g/g ∆Hc = Initial thickness of contamination, cm AB = Area of enclosed space below grade, cm2 Qbuilding = Building ventilation rate, cm3/s Csource = Vapor concentration at the source of contamination, g/cm3-v J = Exposure interval, s LT 0 = Source-building separation at time = 0, cm and; eff β =   DT AB     1− exp  − Qsoil Lcrack    + 1 (21)  LO T Qsoil   D crack Acrack  and; eff Ψ = DT Csource . (22) LO()2 ρb CRT 24 Implicit in Equation 20 is the assumption that source depletion occurs from the top boundary of the contaminated zone as contaminant volatilizes and moves upward toward the soil surface. This creates a hypothetical "dry zone" (δ) that grows with time; conversely, the "wet zone" of contamination retreats proportionally. When the thickness of the depletion zone (δ) is equal to the initial thickness of contamination (∆Hc), the source is totally depleted. The unitless expression (LT0/)Hc)[($2 + 2 ΨJ)1/2 -$] in Equation 20 represents the cumulative fraction of the depletion zone at the end of the exposure interval J. Multiplying this expression by the remainder of Equation 20 results in the time-averaged finite source attenuation coefficient (<α>). With a calculated value for <α>, the time-averaged vapor concentration in the building (Cbuilding) is: Cbuilding = 〈α〉 Csource . (23) For extended exposure intervals (e.g., 30 years), the time for source depletion may be less than the exposure interval. The time for source depletion JD) may be calculated by: O τ D = [∆Hc / LT 2 + Ψ β ]2 −β 2 . (24) If the exposure interval (J) is greater than the time for source depletion JD), the time-averaged building vapor concentration may be calculated by a mass balance such that: ρb CR ∆Hc ABCbuilding = Qbuilding τ (25) where Cbuilding = Time-averaged vapor concentration in the building, g/cm3-v Db = Soil dry bulk density at the source of contamination, g/cm3 CR = Initial soil concentration, g/g )Hc = Initial thickness of contamination, cm AB = Area of enclosed space below grade, cm2 Qbuilding = Building ventilation rate, cm3/s J = Exposure interval, s. 25 2.7 THE SOIL GAS MODELS Use of the J&E Model has typically relied on a theoretical partitioning of the total volume soil concentration into the sorbed, aqueous, and vapor phases. The model has also relied on a theoretical approximation of vapor transport by diffusion and convection from the source of emissions to the building floor in contact with the soil. Use of measured soil gas concentrations directly beneath the building floor instead of theoretical vapor concentrations and vapor transport has obvious advantages that would help to reduce the uncertainty in the indoor air concentration estimates made by the model. The soil gas models (SG-SCREEN and SG-ADV) are designed to allow the user to input measured soil gas concentration and sampling depth information directly into the spreadsheets. In the new models, the value of the user-defined soil gas concentration is assigned as the value of Csource in Equation 19. The steady-state (infinite source) attenuation coefficient (") in Equation 19 is calculated using Equation 13. The steady-state solution for the attenuation coefficient is used because no evaluation has been made regarding the size and total mass of the source of emissions. The source of emissions, therefore, cannot be depleted over time. The soil gas models estimate the steady-state indoor air concentration over the exposure duration. For a detailed discussion of using the soil gas models as well as soil gas sampling, see Section 4 of this document. 2.8 SOIL VAPOR PERMEABILITY Soil vapor permeability (kv) is one of the most sensitive model parameters associated with convective transport of vapors within the zone of influence of the building. Soil vapor permeability is typically measured from field pneumatic tests. If field data are lacking, however, an estimate of the value of kv can be made with limited data. Soil intrinsic permeability is a property of the medium alone that varies with the size and shape of connected soil pore openings. Intrinsic permeability (ki) can be estimated from the soil saturated hydraulic conductivity: ki = Ks µw (26)ρw g where ki = Soil intrinsic permeability, cm2 Ks = Soil saturated hydraulic conductivity, cm/s :w = Dynamic viscosity of water, g/cm-s (= 0.01307 at 10oC) Dw = Density of water, g/cm3 (= 0.999) 26 g = Acceleration due to gravity, cm/s2 (= 980.665). Schaap and Leij (1998) computed the SCS class average values of the saturated hydraulic conductivity (Ks) for each of the 12 SCS soil textural classifications (Table 5). With these values, a general estimate of the value of ki can be made by soil type. As an alternative, in situ measurements of the site-specific saturated hydraulic conductivity can be made and the results input into Equation 26 to compute the value of the soil intrinsic permeability. Effective permeability is the permeability of the porous medium to a fluid when more than one fluid is present; it is a function of the degree of saturation. The relative air permeability of soil (krg) is the effective air permeability divided by the intrinsic permeability and therefore takes into account the effects of the degree of water saturation on air permeability. TABLE 5. CLASS AVERAGE VALUES OF SATURATED HYDRAULIC CONDUCTIVITY FOR THE 12 SCS SOIL TEXTURAL CLASSIFICATIONS Soil texture , USDA Class average saturated hydraulic conductivity, cm/h Sand 26.78 Loamy sand 4.38 Sandy loam 1.60 Sandy clay loam 0.55 Sandy clay 0.47 Loam 0.50 Clay loam 0.34 Silt loam 0.76 Clay 0.61 Silty clay loam 0.46 Silt 1.82 Silty clay 0.40 Parker et al. (1987) extended the relative air permeability model of van Genuchten (1980) to allow estimation of the relative permeabilities of air and water in a two-or three-phase system: 1/ M )2M (27)krg =(1− Ste )1/ 2 (1− Ste where krg = Relative air permeability, unitless (0 ≤ krg ≤ 1) Ste = Effective total fluid saturation, unitless M = van Genuchten shape parameter, unitless. 27 Given a two-phase system (i.e., air and water), the effective total fluid saturation (Ste) is calculated as: (n −θ r ) where Ste = Effective total fluid saturation, unitless 2w = Soil water-filled porosity, cm3/cm3 2r = Residual soil water content, cm3/cm3 n = Soil total porosity, cm3/cm3 . S = (θw −θr ) (28)te Class average values for the parameters 2r and M by SCS soil type may be obtained from Table 3. The effective air permeability (kv) is then the product of the intrinsic permeability (ki) and the relative air permeability (krg) at the soil water-filled porosity 2w. 2.9 CALCULATION OF A RISK-BASED SOIL OR GROUNDWATER CONCENTRATION Both the infinite source model estimate of the steady-state building concentration and the finite source model estimate of the time-averaged building concentration represent the exposure point concentration used to assess potential risks. Calculation of a risk-based media concentration for a carcinogenic contaminant takes the form: C = TR x ATC x 365 days / yr (29)C URF x EF x ED xCbuilding where CC = Risk-based media concentration for carcinogens, :g/kg-soil, or :g/L-water TR = Target risk level, unitless ATC = Averaging time for carcinogens, yr URF = Unit risk factor, :g/m3)-1 EF = Exposure frequency, days/yr ED = Exposure duration, yr 28 Cbuilding = Vapor concentration in the building, :g/m3 per :g/kg-soil, or :g/m3 per :g/L-water. In the case of a noncarcinogenic contaminant, the risk-based media concentration is calculated by: C = THQ x ATNC x 365 days / yr (30)NC 1EF x ED x x C RfC building where CNC = Risk-based media concentration for noncarcinogens, :g/kg-soil, or :g/L-water THQ = Target hazard quotient, unitless ATNC = Averaging time for noncarcinogens, yr EF = Exposure frequency, days/yr ED = Exposure duration, yr RfC = Reference concentration, mg/m3 Cbuilding = Vapor concentration in the building, mg/m3 per :g/kg-soil, or mg/m3 per :g/L-water. The spreadsheets calculate risk-based media concentrations based on a unity initial concentration. That is, soil risk-based concentrations are calculated with an initial hypothetical soil concentration of 1 :g/kg-soil, while for groundwater the initial hypothetical concentration is 1 :g/L­ water. For this reason, the values of Csource and Cbuilding shown on the INTERCALCS worksheet when reverse-calculating a risk-based media concentration do not represent actual values. For these calculations, the following message will appear on the RESULTS worksheet: "MESSAGE: The values of Csource and Cbuilding on the INTERCALCS worksheet are based on unity and do not represent actual values.” When forward-calculating risks from a user-defined initial soil or groundwater concentration, the values of Csource and Cbuilding on the INTERCALCS worksheet are correct. 29 2.10 CALCULATION OF INCREMENTAL RISKS Forward-calculation of incremental risks begins with an actual initial media concentration (i.e., :g/kg-soil or :g/L-water). For carcinogenic contaminants, the risk level is calculated as: URF x EF x ED xC Risk = building (31)ATC x 365 days / yr For noncarcinogenic contaminants, the hazard quotient (HQ) is calculated as: 1EFxEDx x C RfC building HQ = . (32)ATNC x 365 days / yr 2.11 MAJOR MODEL ASSUMPTIONS/LIMITATIONS The following represent the major assumptions/limitations of the J&E Model. 1. Contaminant vapors enter the structure primarily through cracks and openings in the walls and foundation. 2. Convective transport occurs primarily within the building zone of influence and vapor velocities decrease rapidly with increasing distance from the structure. 3. Diffusion dominates vapor transport between the source of contamination and the building zone of influence. 4. All vapors originating from below the building will enter the building unless the floors and walls are perfect vapor barriers. 5. All soil properties in any horizontal plane are homogeneous. 6. The contaminant is homogeneously distributed within the zone of contamination. 7. The areal extent of contamination is greater than that of the building floor in contact with the soil. 8. Vapor transport occurs in the absence of convective water movement within the soil column (i.e., evaporation or infiltration), and in the absence of mechanical dispersion. 9. The model does not account for transformation processes (e.g., biodegradation, hydrolysis, etc.). 30 10. The soil layer in contact with the structure floor and walls is isotropic with respect to permeability. 11. Both the building ventilation rate and the difference in dynamic pressure between the interior of the structure and the soil surface are constant values. Use of the J&E Model as a first-tier screening tool to identify sites needing further assessment requires careful evaluation of the assumptions listed in the previous section to determine whether any conditions exist that would render the J&E Model inappropriate for the site. If the model is deemed applicable at the site, care must be taken to ensure reasonably conservative and self-consistent model parameters are used as input to the model. Considering the limited site data typically available in preliminary site assessments, the J&E Model can be expected to predict only whether or not a risk-based exposure level will be exceeded at the site. Precise prediction of concentration levels is not possible with this approach. The suggested minimum site characterization information for a first tier evaluation of the vapor intrusion pathway includes: site conceptual model, nature and extent of contamination distribution, soil lithologic descriptions, groundwater concentrations, and/or possibly near source soil vapor concentrations. The number of samples and measurements needed to establish this information varies by site and it’s not possible to provide a hard and fast rule. Bulk soil concentrations should not be used unless appropriately preserved during sampling. Based on the conceptual site model (CSM), the user can select the appropriate spreadsheet corresponding to the vapor source at the site and determine whether to use the screening level spreadsheet (which allows only one soil type above the capillary fringe) or the more advanced version (which allows up to three layers above the capillary fringe). Because most of the inputs to the J&E Model are not collected during a typical site characterization, conservative inputs have to be estimated or inferred from available data and other non-site-specific sources of information. The uncertainty in determining key model parameters and sensitivity of the J&E Model to those key model parameters is qualitatively described in Table 6. As shown in the table, building- related parameters will moderate to high uncertainty and model sensitivity include: Qsoil, building crack ratio, building air-exchange rate, and building mixing height. Building-related parameters with low uncertainty and sensitivity include: foundation area, depth to base of foundation, and foundation slab thickness. Of the soil-dependent properties, the soil moisture parameters clearly are of critical importance for the attenuation value calculations. 31 TABLE 6. UNCERTAINTY AND SENSITIVITY OF KEY PARAMETERS FOR THE VAPOR INTRUSION MODEL Input Parameter Parameter Uncertainty Or Variability Shallower Contamination Building Underpressurized Parameter Sensitivity Deeper Contamination Building Not Underpressurized Deeper Contamination Building Underpressurized Shallower Contamination Building Not Underpressurized Soil Total Porosity (n) Low Low Low Low Low Soil Water-filled Porosity (2 w) Moderate to High Low to Moderate Moderate to High Moderate to High Moderate to High Capillary Zone Water-filled Porosity (2n, cz) Moderate to High Moderate to High Moderate to High Moderate to High Moderate to High Thickness of Capillary Zone (Lcz) Moderate to High Moderate to High Moderate to High Moderate to High Moderate to High Soft Dry Bulk Density (D b) Low Low Low Low Low Average Vapor Flowrate into a Building (Qsoil) High Moderate to High Low to Moderate N/A N/A Soil Vapor Permeability(Kv) High Moderate to High Low to Moderate N/A N/A Soil to Building Pressure Differential ()P) Moderate Moderate Low to Moderate N/A N/A Henry’s Law Constant (for single chemical) (H) Low to Moderate Low to Moderate Low to Moderate Low to Moderate Low to Moderate Diffusivity in Air (DA) Low Low Low Low Low Indoor Air Exchange Rate (ER) Moderate Moderate Moderate Moderate Moderate Enclosed Space Height (HB) Moderate Moderate Moderate Moderate Moderate Area of Enclosed Space Below Grade (AB) Low to Moderate Low to Moderate Low to Moderate Low to Moderate Low to Moderate Depth Below Grade to Bottom of Enclosed Space (LF) Low Low Low Low Low Crack-to-Total Area Ratio (0) High Low Low Moderate to High Low to Moderate Enclosed Space Floor Thickness (Lcrack) Low Low Low Low Low 32 SECTION 3 SOIL AND GROUNDWATER MODEL APPLICATION This section provides step-by-step instructions on how to implement the soil and groundwater contamination versions of the J&E Model using the spreadsheets. This section also discusses application of the soil gas versions of the model. The user provides data and selects certain input options, and views model results via a series of worksheets. Error messages are provided within both the data entry worksheet and the results worksheet to warn the user that entered data are missing or outside of permitted limits. The J&E Model as constructed within the accompanying spreadsheets requires a range of input variables depending on whether a screening-level or advanced model is chosen. Table 7 provides a list of all major input variables, the range of practical values for each variable, the default value for each variable, and the relative model sensitivity and uncertainty of each variable. Table 7 also includes references for each value or range of values. Table 8 indicates the results of an increase in the value of each input parameter. The results are shown as either an increase or a decrease in the building concentration (Cbuilding) of the pollutant. An increase in the building concentration will result in an increase in the risk when forward- calculating from an initial soil or groundwater concentration. When reverse-calculating to a risk- based “acceptable” soil or groundwater concentration, an increase in the hypothetical unit building concentration will result in a lower “acceptable” soil or groundwater concentration. A list of reasonably conservative model input parameters for building-related parameters is provided in Table 9, which also provides the practical range, typical or mean value (if applicable), and most conservative value for these parameters. For building parameters with low uncertainty and sensitivity, only a single “fixed” value corresponding to the mean or typical value is provided in Table 9. Soil-dependent properties are provided in Table 10 for soils classified according to the US SCS system. If site soils are not classified according to the US SCS, Table 11 can be used to assist in selecting an appropriate SCS soil type corresponding to the available site lithologic information. Note that the selection of the soil texture class should be biased towards the coarsest soil type of significance, as determined by the site characterization program. 33 TABLE 7. RANGE OF VALUES FOR SELECTED INPUT PARAMETERS Input parameter Practical range of values Default value Soil water-filled porosity (2w) 0.02 – 0.43 cm3/cm3a 0.30 cm3/cm3a Soil vapor permeability (kv) 10-6 – 10-12 cm2b,c 10-8 cm2d Soil-building pressure differential ()P) 0 – 20 Pa3 4 Paf Media initial concentration (CR, Cw) User-defined NA Depth to bottom of soil contamination (Lb) User-defined NA Depth to top of concentration (LT) User-defined NA Floor-wall seam gap (w) 0.05 – 1.0 cme 0.1 cme Soil organic carbon fraction (foc) 0.001 – 0.006a 0.002a Indoor air exchange rate (ER) 0.18 – 1.26 (H-1)g 0.25 (h-1)g,h Soil total porosity (n) 0.34 – 0.53 cm3/cm3a 0.43 cm3/cm3a Soil dry bulk density (Db) 1.25 – 1.75 g/cm3a 1.5 g/cm3a aU.S. EPA (1996a and b). bJohnson and Ettinger (1991). cNazaroff (1988). dBased on transition point between diffusion and convection dominated transport from Johnson and Ettinger (1991). eEaton and Scott (1984); Loureiro et al. (1990). fLoureiro et al. (1990); Grimsrud et al. (1983). gKoontz and Rector (1995). hParker et al. (1990). iU.S. DOE (1995). 34 TABLE 8. EFFECT ON BUILDING CONCENTRATION FROM AN INCREASE IN INPUT PARAMETER VALUES Input parameter Change in parameter value Effect on building concentration Soil water-filled porosity (2w) Increase Decrease Soil vapor permeability (kv) Increase Increase Soil-building pressure differential ()P) Increase Increase Media initial concentration (CR, Cw)a Increase Increase Depth to bottom of soil contamination (Lb)b Increase Increase Depth to top of concentration (LT) Increase Decrease Floor-wall seam gap (w) Increase Increase Soil organic carbon fraction (foc) Increase Decrease Indoor air exchange rate (ER) Increase Decrease Building volumec (LB x WB x HB) Increase Decrease Soil total porosity (n) Increase Increase Soil dry bulk density (Db) Increase Decrease a This parameter is applicable only when forward-calculating risk. b Applicable only to advanced model for soil contamination. c Used with building air exchange rate to calculate building ventilation rate. 35 TABLE 9. BUILDING-RELATED PARAMETERS FOR THE VAPOR INTRUSION MODEL Input Parameter Units Fixed or Variable Typical or Mean Value Range Conservative Value Default Value Total Porosity cm3/cm3 Fixed Specific to soil texture, see Table 10 Unsaturated Zone Water- filled Porosity cm3/cm3 Variable Specific to soil texture, see Table 10 Capillary Transition zone Water-filled Porosity cm3/cm3 Fixed Specific to soil texture, see Table 10 Capillary Transition Zone height cm3/cm3 Fixed Specific to soil texture, see Table 10 Qsoil L/min Variable Specific to soil texture, see Table 10 Soil air permeability m2 Variable Specific to soil texture, see Table 10 Building Depressurization Pa Variable 4 0-15 15 N/A Henry’s law constant (for single chemical) -Fixed Specific to chemical, see Appendix B Free-Air Diffusion Coefficient (single chemical) -Fixed Specific to chemical, see Appendix B Building Air exchange Rate hr-1 Variable 0.5 0.1-1.5 0.1 0.25 Building Mixing height – Basement scenario m Variable 3.66 2.44-4.88 2.44 3.66 Building Mixing height – Slab-on-grade scenario m Variable 2.44 2.13-3.05 2.13 2.44 Building Footprint Area – Basement Scenario m2 Variable 120 80-200+ 80 100 Building Footprint Area – Slab-on-Grade Scenario m2 Variable 120 80-200+ 80 100 Subsurface Foundation area – Basement Scenario m2 Variable 208 152-313+ 152 180 Subsurface Foundation area – Slab-on-Grade Scenario m2 Fixed 127 85-208+ 85 106 Depth to Base of Foundation – Basement Scenario m Fixed 2 N/A N/A 2 Depth to Base of Foundation – Slab-on-Grade Scenario m Fixed 0.15 N/A N/A 0.15 Perimeter Crack Width mm Variable 1 0.5-5 5 1 Building Crack ratio – Slab- on-Grade Scenario dimensionless Variable 0.00038 0.00019-0.0019 0.0019 3.77 x 10-4 Building Crack ratio – Basement Scenario dimensionless Variable 0.0002 0.0001-0.001 0.001 2.2 x 10-4 Crack Dust Water-Filled Porosity cm3/cm3 Fixed Dry N/A N/A Dry Building Foundation Slab Thickness m Fixed 0.1 N/A N/A 0.1 36 TABLE 10. SOIL-DEPENDENT PROPERTIES FOR THE VAPOR INTRUSION MODEL - FIRST TIER ASSESSMENT U.S. Soil Saturated Conservation Water Residual Service (SCS) Content Water Soil Texture Total Porosity Content θs (cm 3/cm 3) θr (cm 3/cm 3) Unsaturated Zone Capillary Transition Zone Saturated Water-Filled Porosity Water θw,cap Height Mean or Typical Content Cap Cap Zone (FC1/3bar+θr)/2 Range Conservative Modeled Total Porosity @ air-entry Fetter (94) θw,unsat (cm 3/cm 3) θw,unsat (cm 3/cm 3) θw,unsat (cm 3/cm 3) θw,unsat (cm 3/cm 3) θs (cm 3/cm 3) (cm) Clay 0.459 0.098 Clay Loam 0.442 0.079 Loam 0.399 0.061 Loamy Sand 0.39 0.049 Silt 0.489 0.05 Silt Loam 0.439 0.065 Silty Clay 0.481 0.111 Silty Clay Loam 0.482 0.09 Sand 0.375 0.053 Sandy Clay 0.385 0.117 Sandy Clay Loam 0.384 0.063 Sandy Loam 0.387 0.039 Loamy Sand 0.39 0.049 0.215 0.098-0.33 0.098 0.215 0.459 0.412 81.5 0.168 0.079-0.26 0.079 0.168 0.442 0.375 46.9 0.148 0.061-0.24 0.061 0.148 0.399 0.332 37.5 0.076 0.049-0.1 0.049 0.076 0.39 0.303 18.8 0.167 0.05-0.28 0.050 0.167 0.489 0.382 163.0 0.180 0.065-0.3 0.065 0.180 0.439 0.349 68.2 0.216 0.11-0.32 0.111 0.216 0.481 0.424 192.0 0.198 0.09-0.31 0.090 0.198 0.482 0.399 133.9 0.054 0.053-0.055 0.053 0.054 0.375 0.253 17.0 0.197 0.117-0.28 0.117 0.197 0.385 0.355 30.0 0.146 0.063-0.23 0.063 0.146 0.384 0.333 25.9 0.103 0.039-0.17 0.039 0.103 0.387 0.320 25.0 0.076 0.049-0.1 0.049 0.076 0.39 0.303 18.8 TABLE 11. GUIDANCE FOR SELECTION OF SOIL TYPE If your boring log indicates that the following materials are the predominant soil types … Then you should use the following texture classification when obtaining the attenuation factor Sand or Gravel or Sand and Gravel, with less than about 12 % fines, where “fines” are smaller than 0.075 mm in size. Sand Sand or Silty Sand, with about 12 % to 25 % fines Loamy Sand Silty Sand, with about 20 % to 50 % fines Sandy Loam Silt and Sand or Silty Sand or Clayey, Silty Sand or Sandy Silt or Clayey, Sandy Silt, with about 45 to 75 % fines Loam Sandy Silt or Silt, with about 50 to 85 % fines Silt Loam These input parameters were developed from the best available soil-physics science, available studies of building characteristics, and international-expert opinion. Consequently, the input parameters listed in Tables 9 and 10 are considered default parameters for a first-tier assessment, which should in most cases provide a reasonably (but not overly) conservative estimate of the vapor intrusion attenuation factor for a site. Justification for the building-related and soil- dependent parameters values selected as default values for the J&E Model is described below. 3.1 JUSTIFICATION OF DEFAULT SOIL-DEPENDENT PROPERTIES The default soil-dependent parameters recommended for a first tier assessment (Table 10) represent mean or typical values, rather than the most conservative value, in order to avoid overly conservative estimates of attenuation factors. Note, however, that the range of values for some 37 soil properties can be very large, particularly in the case of moisture content and hydraulic conductivity. Consequently, selecting a soil type and corresponding typical soil property value may not accurately or conservatively represent a given site. Note also that Table 9 does not provide estimates of soil properties for very coarse soil types, such as gravel, gravelly sand, and sandy gravel, etc., which also may be present in the vadose zone. Consequently, in cases where the vadose zone is characterized by very coarse materials, the J&E Model may not provide a conservative estimate of attenuation factor. As discussed above, the J&E Model is sensitive to the value of soil moisture content. Unfortunately, there is little information available on measured moisture contents below buildings. Therefore, the typical approach is to use a water retention model (e.g., van Genuchten model) to approximate moisture contents. For the unsaturated zone, the selected default value for soil moisture is a value equal to halfway between the residual saturation value and field capacity, using the van Genuchten model-predicted values for U.S. SCS soil types. For the capillary transition zone, a moisture content corresponding to the air entry pressure head is calculated by using the van Genuchten model. When compared to other available water retention models, the van Genuchten model yields somewhat lower water contents, which results in more conservative estimates of attenuation factor. The soil moisture contents listed in Table 10 are based on agricultural samples, which are likely to have higher water contents than soils below building foundations and, consequently result in less-conservative estimates of the attenuation factor. 3.2 JUSTIFICATION OF DEFAULT BUILDING-RELATED PROPERTIES Building Air Exchange Rate (Default Value = 0.25 AEH) The results of 22 studies for which building air exchange rates are reported in Hers et al. (2001). Ventilation rates vary widely from approximately 0.1 AEH for energy efficient “air-tight” houses (built in cold climates) (Fellin and Otson, 1996) to over 2 AEH (AHRAE (1985); upper range). In general, ventilation rates will be higher in summer months when natural ventilation rates are highest. Murray and Burmaster (1995) conducted one of the most comprehensive studies of U.S. residential air exchange rates (sample size of 2844 houses). The data set was analyzed on a seasonal basis and according to climatic region. When all the data were analyzed, the 10th, 50th and 90th percentile values were 0.21, 0.51 and 1.48 AEH. Air exchange rates varied depending on season and climatic region. For example, for the winter season and coldest climatic area (Region 1, e.g., Great Lakes area and extreme northeast U.S.), the 10th, 50th , and 90th percentile values were 0.11, 0.27 and 0.71 AEH, respectively.. In contrast, for the winter season and warmest climatic area [Region 4 (southern California, Texas, Florida, Georgia)], the 10th, 50th, and 90th percentile values were 0.24, 0.48 and 1.13 AEH, respectively. Although building air exchange rates would be higher during the summer months, vapor intrusion during winter months (when house depressurization is expected to be most significant) would be of greatest concern. For this guidance, a default value of 0.25 for air exchange rate was selected to represent the lower end of these distributions. 38 Crack Width and Crack Ratio (Default Value = 0.0002 for basement house; = 0.0038 for slab-on- grade house) The crack width and crack ratio are related. Assuming a square house and that the only crack is a continuous edge crack between the foundation slab and wall (“perimeter crack”), the crack ratio and crack width are related as follows: Crack Ratio = Crack Width x 4 x (Subsurface Foundation Area)^0.5/Subsurface Foundation Area Little information is available on crack width or crack ratio. One approach used by radon researchers is to back-calculate crack ratios using a model for soil gas flow through cracks and the results of measured soil gas flow rates into a building. For example, the back-calculated values for a slab/wall edge crack based on soil gas-entry rates reported in Nazaroff (1992), Revzan et al. (1991), and Nazaroff et al. (1985) range from about 0.0001 to 0.001. Another possible approach is to measure crack openings although this, in practice, is difficult to do. Figley and Snodgrass (1992) present data from 10 houses where edge crack measurements were made. At the eight houses where cracks were observed, the crack widths ranged from hairline cracks up to 5 mm wide, while the total crack length per house ranged from 2.5 m to 17.3 m. Most crack widths were less than 1 mm. The suggested defaults for crack ratio in regulatory guidance, literature, and models also vary. In ASTM E1739-95, a default crack ratio of 0.01 is used. The crack ratios suggested in the VOLASOIL model (developed by the Dutch Ministry of Environment) range from 0.0001 to 0.000001. The VOLASOIL model values correspond to values for a “good” and “bad” foundation, respectively. The crack ratio used by J&E (1991) for illustrative purposes ranged from 0.001 to 0.01. The selected default values fall within the ranges observed. Building Area and Subsurface Foundation Area (Default Value = 10 m by 10 m) The default building area is based on the following information: • Default values used in the Superfund User’s Guide (9.61 m by 9.61 m or 92.4 m2) • Default values used by the State of Michigan, as documented in Part 201, Generic Groundwater and Soil Volatilization to Indoor Air Inhalation Criteria: Technical Support Document (10.5 m by 10.5 m of 111.5 m2). The Michigan guidance document indicates that the 111.5 m2 area approximately corresponds to the 10th percentile floor space area for a residential single-family dwelling, based on statistics compiled by the U.S. Department of Commerce (DOC) and U.S. Housing and Urban Development (HUD). The typical, upper, and lower ranges presented in Table 9 are subjectively chosen values. The subsurface foundation area is a function of the building area, and depth to the base of the foundation, which is fixed. 39 Building Mixing Height (Default Value = 2.44 m for slab-on-grade scenario; = 3.66 m for basement scenario) The J&E Model assumes that subsurface volatiles migrating into the building are completely mixed within the building volume, which is determined by the building area and mixing height. The building mixing height will depend on a number of factors including building height; heating, ventilation, and air conditioning (HVAC) system operation, environmental factors such as indoor- outdoor pressure differentials and wind loading, and seasonal factors. For a single-story house, the variation in mixing height can be approximated by using the room height. For a multi-story house or apartment building, the mixing height will be greatest for houses with HVAC systems that result in significant air circulation (e.g., forced-air heating systems). Mixing heights would likely be less for houses with electrical baseboard heaters. It is likely that mixing height is, to some degree, correlated to the building air exchange rate. Little data are available that provides for direct inference of mixing height. There are few sites, with a small number of houses where indoor air concentrations were above background, and where both measurements at ground level and the second floor were made Colorado Department of Transportation (CDOT), Redfields, Eau Claire). Persons familiar with the data sets for these sites indicate that in most cases a fairly significant reduction in concentrations (factor of two or greater) was observed, although at one site (Eau Claire, “S” residence), the indoor trichloroethylene (TCE) concentrations were similar in both the basement and second floor of the house. For the CDOT site apartments, there was an approximate five-fold reduction between the concentrations measured for the first floor and second floor units (Mr. Jeff Kurtz, EMSI, personal communication, June 2002). Less mixing would be expected for an apartment because there are less cross-floor connections than for a house. The value chosen for a basement house scenario (3.66 m) would be representative of a two-fold reduction or attenuation in vapor concentrations between floors. Qsoil (Default Value = 5 L/min) The method often used with the J&E Model for estimating the soil gas advection rate (Qsoil) through the building envelope is an analytical solution for two-dimensional soil gas flow to a small horizontal drain (Nazaroff 1992) (“Perimeter Crack Model”). Use of this model can be problematic in that Qsoil values are sensitive to soil-air permeability and consequently a wide range in flows can be predicted. An alternate empirical approach is to select a Qsoil value on the basis of tracer tests (i.e., mass balance approach). When soil gas advection is the primary mechanism for tracer intrusion into a building, the Qsoil can be estimated by measuring the concentrations of a chemical tracer in indoor air, in outdoor air, and in soil vapor below a building, and by measuring the building ventilation rate (Hers et al. 2000a; Fischer et al. 1996; Garbesi et al. 1993; Rezvan et al. 1991; Garbesi and Sextro, 1989). For sites with coarse-grained soils (Table 10). The Qsoil values measured using this technique are compared to predicted rates using the Perimeter Crack model. The Perimeter Crack model predictions are both higher and lower than the measured values, but overall are within one order of magnitude of the measured values. Although the Qsoil values predicted by the models and measured 40 using field tracer tests are uncertain, the results suggest that a “typical” range for houses on coarse- grained soils is on the order of 1 to 10 L/min. A disadvantage with the tracer test approach is that only limited data are available and there do not appear to be any tracer studies for field sites with fine-grained soils. It is also important to recognize that the advective zone of influence for soil gas flow is limited to soil immediately adjacent to the building foundation. Some data on pressure coupling provide insight on the extent of the advective flow zone. For example, Garbesi et al. (1993) report a pressure coupling between the soil and experimental basement (i.e., relative to that between the basement and atmosphere) equal to 96 percent directly below the slab, between 29 percent and 44 percent at 1 m below the basement floor slab, and between 0.7 percent and 27 percent at a horizontal distance of 2 m from the basement wall. At the Chatterton site (research site investigated by the author), the pressure coupling immediately below the building floor slab ranged from 90 to 95 percent and at a depth of 0.5 m was on the order of 50 percent. These results indicate that the advective zone of influence will likely be limited to a zone within 1 to 2 m of the building foundation. Because the advective flow zone is relatively limited in extent, the soil type adjacent to the building foundation is of importance. In many cases, coarse-grained imported fill is placed below foundations, and either coarse-grained fill, or disturbed, loose fill is placed adjacent to the foundation walls. Therefore, a conservative approach for the purposes of this guidance is to assume that soil gas flow will be controlled by coarse-grained soil, and not rely on the possible reduction in flow that would be caused by fine-grained soils near to the house foundation. For these reasons, a soil gas flow rate of 5 L/min (midpoint between 1 and 10 L/min) was chosen as the input value. 3.3 RUNNING THE MODELS Eight different models are provided in MICROSOFT EXCEL formats. 1. Models for Soil Contamination: SL-SCREEN-Feb 03.XLS SL-ADV-Feb 03.XLS 2. Models for Groundwater Contamination: GW-SCREEN-Feb 03.XLS GW-ADV-Feb 03.XLS 3. Model for Soil Gas Contamination SG-SCREEN-Feb 03.xls SG-ADV-Feb 03.xls 4. Models for Non Aqueous Phase Liquids NAPL-SCREEN-Feb 03.xls 41 NAPL-ADV-Feb 03.xls Both the screening-level models and the advanced models allow the user to calculate a risk- based media concentration or incremental risks from an actual starting concentration in soil or in groundwater. Data entry within the screening-level models is limited to the most sensitive model parameters and incorporates only one soil stratum above the contamination. The advanced models provide the user with the ability to enter data for all of the model parameters and also incorporate up to three individual soil strata above the contamination for which soil properties may be varied. To run any of the models, simply open the appropriate model file within MICROSOFT EXCEL. Each model is constructed of the following worksheets: 1. DATENTER (Data Entry Sheet) 2. CHEMPROPS (Chemical Properties Sheet) 3. INTERCALCS (Intermediate Calculations Sheet) 4. RESULTS (Results Sheet) 5. VLOOKUP (Lookup Tables). The following is an explanation of what is contained in each worksheet, how to enter data, how to interpret model results, and how to add/revise the chemical properties data found in the VLOOKUP Tables. As examples, Appendix C contains all the worksheets for the advanced soil contamination model SL-ADV. 3.4 THE DATA ENTRY SHEET (DATENTER) Figure 4 is an example of a data entry sheet. In this case, it shows the data entry sheet for the screening-level model for contaminated groundwater (GW-SCREEN). Figure 5 is an example of an advanced model data entry sheet (GW-ADV). Note that the screening-level model sheet requires entry of considerably less data than does the advanced sheet. To enter data, simply position the cursor within the appropriate box and type the value; all other cells are protected. Error Messages In the case of the screening-level models, all error messages will appear in red type below the applicable row of data entry boxes. For the advanced models, error messages may appear on the data entry sheet or in the lower portion of the results sheet. Error messages will occur if required entry data are missing or if data are out of range or do not conform to model conventions. The error message will tell the user what kind of error has occurred. 42 Figure 4. GW-SCREEN Data Entry Sheet 43 Figure 5. GW-ADV Data Entry Sheet 44 Figure 6 is an example of an error message appearing on the data entry sheet. Figure 7 illustrates error messages appearing within the message and error summary section on the results sheet (advanced models only). Entering Data Each data entry sheet requires the user to input values for model variables. Data required for the soil contamination scenario will differ from that required for the groundwater contamination scenario. In addition, data required for the screening-level models will differ from that required for the advanced models. Model Variables-­ The following is a list of all data entry variables required for evaluating either a risk-based media concentration or the incremental risks due to actual contamination. A description for which model(s) the variable is appropriate is given in parenthesis after the name of the variable. In addition, notes on how the variable is used in the calculations and how to determine appropriate values of the variable are given below the variable name. A quick determination of which variables are required for a specific model can be made by reviewing the data entry sheet for the model chosen. Example data entry sheets for each model can be found in Appendix D. 1. Calculate Risk-Based Concentration or Calculate Incremental Risks from Actual Concentration (All Soil and Groundwater Models) The model will calculate either a risk-based soil or groundwater concentration or incremental risks but cannot calculate both simultaneously. Enter an "X" in only one box. 2. Chemical CAS No. (All Models) Enter the appropriate CAS number for the chemical you wish to evaluate; do not enter dashes. The CAS number entered must exactly match that of the chemical, or the error message "CAS No. not found" will appear in the "Chemical" box. Once the correct CAS number is entered, the name of the chemical will automatically appear in the "Chemical" box. A total of 108 chemicals and their associated properties are included with each model; see Section 3.7 for instructions on adding/revising chemicals. 45 Figure 6. Example Error Message on Data Entry Sheet Figure 7. Example Error Message on Results Sheet 46 3. Initial Soil or Groundwater Concentration (All Soil and Groundwater Models) (Lw) Enter a value only if incremental risks are to be calculated. Be sure to enter the concentration in units of :g/kg (wet weight basis soil) or :g/L (groundwater). Typically, this value represents the average concentration within the zone of contamination. If descriptive statistics are not available to quantify the uncertainty in the average value, the maximum value may be used as an upper bound estimate. 4. Average Soil/Groundwater Temperature (All Models) (Ts) The soil/groundwater temperature is used to correct the Henry's law constant to the specified temperature. Figure 8 from U.S. EPA (1995) shows the average temperature of shallow groundwater in the continental United States. Shallow groundwater temperatures may be used to approximate subsurface soil temperatures greater than 1 to 2 meters below the ground surface. Another source of information may be your State groundwater protection regulatory agency. 5. Depth Below Grade to Bottom of Enclosed Space Floor (All Models) (LF) Enter the depth to the bottom of the floor in contact with the soil. The default value for slab-on-grade and basement construction is 15 cm and 200 cm, respectively. 6. Depth Below Grade to Top of Contamination (Soil Models Only) (LT) Enter the depth to the top of soil contamination. If the contamination begins at the soil surface, enter the depth below grade to the bottom of the enclosed space floor. The depth to the top of contamination must be greater than or equal to the depth to the bottom of the floor. 47 F i g u re 8 . Av e r a g e S h a l l o w G r o u n d w a t er T e m p e r a t u r e i n t h e U n i t e d S t a t e s 48 7. Depth Below Grade to Water Table (Groundwater Models Only) (Lwt) Enter the depth to the top of the water table (i.e., where the pressure head is equal to zero and the pressure is atmospheric). Note: The thickness of the capillary zone is calculated based on the SCS soil textural classification above the top of the water table. The depth below grade to the top of the water table minus the thickness of the capillary zone must be greater than the depth below grade to the bottom of the enclosed space floor. This means that the top of the capillary zone is always below the floor. 8. Depth Below Grade to Bottom of Contamination (Advanced Soil Model Only) (LB) This value is used to calculate the thickness of soil contamination. A value greater than zero and greater than the depth to the top of contamination will automatically invoke the finite source model. If the thickness of contamination is unknown, two options are available: 1. Entering a value of zero will automatically invoke the infinite source model. 2. Enter the depth to the top of the water table. This will invoke the finite source model under the assumption that contamination extends from the top of contamination previously entered down to the top of the water table. 9. Thickness of Soil Stratum "X" (Advanced Models Only) (hx, x = A, B, or C) In the advanced models, the user can define up to three soil strata between the soil surface and the top of contamination or to the soil gas sampling depth, as appropriate. These strata are listed as A, B, and C. Stratum A extends down from the soil surface, Stratum B is below Stratum A, and Stratum C is the deepest stratum. The thickness of Stratum A must be at least as thick as the depth below grade to the bottom of the enclosed space floor. The combined thickness of all strata must be equal to the depth to the top of contamination, or to the soil gas sampling depth, as appropriate. If soil strata B and/or C are not to be considered, a value of zero must be entered for each stratum not included in the analysis. 10. Soil Stratum A SCS Soil Type (Advanced Models Only) (SES – soil) Enter one of the following SCS soil type abbreviations: 49 Abbreviation C CL L LS S SC SCL SI SIC SICL SIL SL SCS Soil Type Clay Clay loam Loam Loamy sand Sand Sandy clay Sandy clay loam Silt Silty clay Silty clay loam Silty loam Sandy loam The SCS soil textural classification can be determined by using either the ATSM Standard Test Method for Particle-Size Analysis of Soils (D422-63) or by using the analytical procedures found in the U.S. Natural Resources Conservation Service (NRCS) Soil Survey Laboratory Methods Manual, Soil Survey Laboratory Investigations Report No. 42. After determining the particle size distribution of a soil sample, the SCS soil textural classification can be determined using the SCS classification chart in Figure 7. The SCS soil type along with the Stratum A soil water-filled porosity is used to estimate the soil vapor permeability of Stratum A which is in contact with the floor and walls of the enclosed space below grade. Alternatively, the user may define a soil vapor permeability (see Variable No. 11). 50 11. User-Defined Stratum A Soil Vapor Permeability (Advanced Models Only)(Kv) As an alternative to estimating the soil vapor permeability of soil Stratum A, the user may define the soil vapor permeability. As a general guide, the following represent the practical range of vapor permeabilities: Soil type Medium sand Fine sand Silty sand Clayey silts Soil vapor permeability, cm2 1.0 x 10-7 to 1.0 x 10-6 1.0 x 10-8 to 1.0 x 10-7 1.0 x 10-9 to 1.0 x 10-8 1.0 x 10-10 to 1.0 x 10-9 12. Vadose Zone SCS Soil Type (Screening Models Only) (SCS – soil ) Because the screening-level models accommodate only one soil stratum above the top of contamination or soil gas sampling depth, enter the SCS soil type from the list given in Variable No. 10. 13. User-Defined Vadose Zone Soil Vapor Permeability (Screening Models Only) (Kv) For the same reason cited in No. 12 above, the user may alternatively define a soil vapor permeability. Use the list of values given in Variable No. 11 as a general guide. 14. Soil Stratum Directly Above the Water Table (Advanced Groundwater Models Only) (A, B, or C) Enter either A, B, or C as the soil stratum directly above the water table. This value must be the letter of the deepest stratum for which a thickness value has been specified under Variable No. 9. 15. SCS Soil Type Directly Above Water Table (Groundwater Models Only) (SCS – soil) Enter the correct SCS soil type from the list given in Variable No. 10 for the soil type directly above the water table. The soil type entered is used to estimate the rise (thickness) of the capillary zone. 51 16. Stratum "X" Soil Dry Bulk Density (Advanced Models Only) (Px, x = A, B, or C) Identify the soil type for each strata and accept the default value or enter a site- specific value for the average soil dry bulk density. Dry bulk density is used in a number of intermediate calculations and is normally determined by field measurements (ASTM D 2937 Method). 17. Stratum "X" Soil Total Porosity (Advanced Models Only) (nx, x = A, B, or C) Total soil porosity (n) is determined as: n = 1 Db/Ds where Db is the soil dry bulk density (g/cm3) and Ds is the soil particle density (usually 2.65 g/cm3). x18. Stratum "X" Soil Water-Filled Porosity (Advanced Models Only) (2w , X = a, b, or c) Enter the average long-term volumetric soil moisture content; this is typically a depth-averaged value for the appropriate soil stratum. A long-term average value is typically not readily available. Do not use values based on episodic measurements unless they are representative of long-term conditions. One option is to use a model to estimate the long-term average soil water-filled porosities of each soil stratum between the enclosed space floor and the top of contamination. The HYDRUS model version 5.0 (Vogel et al., 1996) is a public domain code for simulating one-dimensional water flow, solute transport, and heat movement in variably-saturated soils. The water flow simulation module of HYDRUS will generate soil water content as a function of depth and time given actual daily precipitation data. Model input requirements include either the soil hydraulic properties of van Genuchten (1980) or those of Brooks and Corey (1966). The van Genuchten soil hydraulic properties required are the same as those given in Tables 3 and 4 (i.e., θs, θr, N, " 1, and Ks). The HYDRUS model is available from the U.S. Department of Agriculture (USDA) - Agricultural Research Service in Riverside, California via their internet website at http://www.ussl.ars.usda.gov/MODELS/HYDRUS.HTM. One and two-dimensional commercial versions of HYDRUS (Windows versions) are available at the International Ground Water Modeling Center website at http://www.mines.edu/research/igwmc/software/. Schaap and Leij (1998) have recently developed a Windows program entitled ROSETTA for estimating the van Genuchten soil hydraulic properties based on a limited or more extended set of input data. The ROSETTA program can be found at the USDA website: http://www.ussl.ars.usda.gov/MODELS/rosetta/rosetta.htm. The van Genuchten 52 hydraulic properties can then be input into HYDRUS to estimate soil moisture content. 19. Stratum "X" Soil Organic Carbon Fraction (Advanced Soil Models Only) (focx, X = A, B, or c) Enter the depth-averaged soil organic carbon fraction for the stratum specified. Soil organic carbon is measured by burning off soil carbon in a controlled-temperature oven. This parameter, along with the chemical's organic carbon partition coefficient (Koc), is used to determine the soil-water partition coefficient (Kd). 20. Vadose Zone Soil Dry Bulk Density (Screening Models Only) (DA) Because the screening-level models accommodate only one soil stratum above the top of contamination, identify the soil type and accept the default values or enter the depth-averaged soil dry bulk density. The universal default value is 1.5 g/cm3, which is consistent with U.S. EPA (1996a and b) for subsurface soils. 21. Vadose Zone Soil Total Porosity (Screening Models Only) (mA) Because the screening-level models accommodate only one soil stratum above the top of contamination, enter the depth-averaged soil total porosity. The default value is 0.43, which is consistent with U.S. EPA (1996a and b) for subsurface soils. 22. Vadose Zone Soil Water-Filled Porosity (Screening Models Only) (2wA) Because the screening-level models accommodate only one soil stratum above the top of contamination, enter the depth-averaged soil water-filled porosity. The default value is 0.30, which is consistent with U.S. EPA (1996a and b) for subsurface soils. 23. Vadose Zone Soil Organic Carbon Fraction (Soil Screening Model Only) (focA) Because the screening-level models accommodate only one soil stratum above the top of contamination, enter the depth-averaged soil organic carbon fraction. The default value is 0.002, which is consistent with U.S. EPA (1996a and b) for subsurface soils. 24. Enclosed Space Floor Thickness (Advanced Models Only) (Lcrack) Enter the thickness of the floor slab. All models operate under the assumption that the floor in contact with the underlying soil is composed of impermeable concrete whether constructed as a basement floor or slab-on-grade. The default value is 10 cm, which is consistent with J&E (1991). 53 25. Soil-Building Pressure Differential (Advanced Models Only) ()P) Because of wind effects on the structure, stack effects due to heating of the interior air, and unbalanced mechanical ventilation, a negative pressure with respect to the soil surface is generated within the structure. This pressure differential ()P) induces a flow of soil gas through the soil matrix and into the structure through cracks, gaps, and openings in the foundation. The effective range of values of )P is 0-20 pascals (Pa) (Loureiro et al., 1990; Eaton and Scott, 1984). Individual average values for wind effects and stack effects are approximately 2 Pa (Nazaroff et al., 1985; Put and Meijer, 1989). Typical values for the combined effects of wind pressures and heating are 4 to 5 Pa (Loureiro et al., 1990; Grimsrud et al., 1983). A conservative default value of )P was therefore chosen to be 4 Pa (40 g/cm-s2). For more information on estimating site-specific values of )P, the user is referred to Nazaroff et al. (1987) and Grimsrud et al. (1983). 26. Enclosed Space Floor Length (Advanced Models Only) (LB) The default value is 1000 cm (see Variable No. 28). 27. Enclosed Space Floor Width (Advanced Models Only) (WB) The default value is 1000 cm (see Variable No. 28). 28. Enclosed Space Height (Advanced Models Only) (HB) For a single story home, the variation in mixing height will be the greatest for houses with HVAC systems that result in significant air circulation (e.g., forced air heat pump). Mixing heights would be less for houses with electrical baseboard heaters. The mixing height is approximated by the room height. The default value is 2.44 meters for a single story house without a basement. For a single story house with a basement less mixing would be expected because of the cross floor connections. The default values for a house with a basement is 3.66 m. This value represents a two-fold reduction in vapor concentrations between the floors. 29. Floor-Wall Seam Crack Width (Advanced Models Only) (W) The conceptual model used in the spreadsheets follows that of Loureiro et al. (1990) and Nazaroff (1988) and is illustrated in Figure 9. The model is based on a single- family house with a poured concrete basement floor and wall foundations, or constructed slab-on-grade in similar fashion. A gap is assumed to exist at the 54 Figure 9. Floor Slab and Foundation junction between the floor and the foundation along the perimeter of the floor. The gap exists as a result of building design or concrete shrinkage. This gap is assumed to be the only opening in the understructure of the house and therefore the only route for soil gas entry. Eaton and Scott (1984) reported typical open areas of approximately 300 cm2 for the joints between walls and floor slabs of residential structures in Canada. Therefore, given the default floor length and width of 1000 cm, a gap width (w) of 0.1 cm equates to a total gap area of 900 cm2, which is reasonable given the findings of Eaton and Scott. This value of the gap width is also consistent with the typical value reported in Loureiro et al. (1990). The default value of the floor-wall seam crack width was therefore set equal to 0.1 cm. 55 30. Indoor Air Exchange Rate (Advanced Models Only) (ER) The indoor air exchange rate is used along with the building dimensions to calculate the building ventilation rate. The default value of the indoor air exchange rate is 0.25/h. This value is consistent with the 10th percentile of houses in all regions of the U.S., as reported in Koontz and Rector (1995). This value is also consistent with the range of the control group of 331 houses in a study conducted by Parker et al. (1990) to compare data with that of 292 houses with energy-efficient features in the Pacific Northwest. 31. Averaging Time for Carcinogens (All Models) (ATc) Enter the averaging time in units of years. The default value is 70 years. 32. Averaging Time for Noncarcinogens (All Models) (ATnc) Enter the averaging time in units of years. The averaging time for noncarcinogens is set equal to the exposure duration. The default value for residential exposure from U.S. EPA (1996a and b) is 30 years. 33. Exposure Duration (All Models) (ED) Enter the exposure duration in units of years. The default value for residential exposure from U.S. EPA (1996a and b) is 30 years. 34. Exposure Frequency (All Models) (EF) Enter the exposure frequency in units of days/yr. The default value for residential exposure from U.S. EPA (1996a and b) is 350 days/yr. 35. Target Risk for Carcinogens (All Soil and Groundwater Models) (TR) If a risk-based media concentration is to be calculated, enter the target risk-level. The default value is 1 x 10-6. 36. Target Hazard quotient for Noncarcinogens (All Soil and Groundwater Models) (THQ) If a risk-based media concentration is to be calculated, enter the target hazard quotient. The default value is 1. 56 The remaining four worksheets include the results sheet (RESULTS) and three ancillary sheets. The ancillary sheets include the chemical properties sheet (CHEMPROPS), the intermediate calculations sheet (INTERCALCS), and the lookup tables (VLOOKUP). 3.5 THE RESULTS SHEET (RESULTS) Once all data are entered in the data entry sheet, the model results may be viewed on the RESULTS sheet. For the soil and groundwater models, calculations are presented as either a risk- based soil or groundwater concentration, or the incremental risks associated with an initial soil or groundwater concentration. In the case of the advanced models, the user should check the message and error summary below the results section to ensure that no error messages appear. If one or more error messages appear, re-enter the appropriate data. The RESULTS worksheet shows the indoor exposure soil or groundwater concentration for either a carcinogen or noncarcinogen as appropriate. When a contaminant is both a carcinogen and a noncarcinogen, the risk-based indoor exposure concentration is set equal to the lower of these two values. In addition, the soil saturation concentration (Csat) or the aqueous solubility limit (S) is also displayed for the soil and groundwater models, respectively. The equilibrium vapor concentration at the source of contamination is limited by the value of Csat for soil contamination and by the value of S for groundwater contamination, as appropriate. For a single contaminant, the vapor concentration directly above the source of soil contamination cannot be greater than that associated with the soil saturation concentration; for groundwater contamination, the vapor concentration cannot be greater than that associated with the solubility limit. As a result, subsurface soil concentrations greater than Csat and groundwater concentrations greater than S will not produce higher vapor concentrations. Therefore, if the indoor vapor concentration predicted from a soil concentration greater than or equal to the value of Csat and it does not exceed the health-based limit in indoor air (target risk or target hazard quotient), the vapor intrusion pathway will not be of concern for that particular chemical. The same is true for an indoor vapor concentration predicted from a groundwater concentration greater than or equal to the value of S. That does not necessarily mean, however, that the subsurface contamination will not be of concern from a groundwater protection standpoint, (ingestion) and the potential for free-phase contamination (e.g., NAPL) must also be addressed. For subsurface soils, the physical state of a contaminant at the soil temperature plays a significant role. When a contaminant is a liquid (or gas) at the soil temperature, the upper limit of the soil screening level is set at Csat. This tends to reduce the potential for NAPL to exist within the vadose zone. The case is different for a subsurface contaminant that is a solid at the soil temperature. In this case, the screening level is not limited by Csat because of the reduced possibility of leaching to the water table. If the model estimates a risk-based screening level greater than Csat for a solid in soils, the model will display the final soil concentration as "NOC" or Not of Concern for the vapor intrusion pathway. 57 In the case of groundwater contamination, the physical state of the contaminant is not an issue in that the contamination has already reached the water table. Because the equilibrium vapor concentration at the source of emissions cannot be higher than that associated with the solubility limit, the vapor concentration is calculated at the solubility limit if the user enters a groundwater concentration greater than the value of S when forward-calculating risk. When reverse-calculating a risk-based groundwater concentration, the model will display the final groundwater concentration as "NOC" for the vapor intrusion pathway if the model calculates a risk-based level greater than or equal to the value of S. It should be noted, however, that if the soil properties or other conditions specified in the DATENTER worksheet are changed, the final risk-based soil or groundwater concentration must be remodeled. It should also be understood that if a contaminant is labeled "Not of Concern" for the vapor intrusion pathway, all other relevant exposure pathways must be considered for both contaminated soils and groundwater. 3.6 THE CHEMICAL PROPERTIES SHEET (CHEMPROPS) The chemical properties sheet provides a summary of the chemical and toxicological properties of the chemical selected for analysis. These data are retrieved from the VLOOKUP sheet by CAS number. All data in the chemical properties sheet are protected. 3.7 THE INTERMEDIATE CALCULATIONS SHEET (INTERCALS) The intermediate calculations sheet provides solutions to intermediate variables. Review of the values of the intermediate variables may be helpful in an analysis of the cause-and-effect relationships between input values and model results. All data in the intermediate calculations sheet are protected. 3.8 THE LOOKUP TABLES (VLOOKUP) The VLOOKUP sheet contains two lookup tables from which individual data are retrieved for a number of model calculations. The first table is the Soil Properties Lookup Table. This table contains the average soil water retention curve data of Hers (2002) and Schaap and Leij (1998) and the mean grain diameter data of Nielson and Rogers (1990) by SCS soil type, and the mean dry bulk density from Leij, Stevens, et al (1994). 3.9 ADDING, DELETING, OR REVISING CHEMICALS Data for any chemical may be edited, new chemicals added, or existing chemicals deleted from the Chemical Properties Lookup Table within the VLOOKUP worksheet. To begin an editing 58 session, the user must unprotect (unseal) the worksheet (the password is "ABC" in capital letters); editing of individual elements or addition and deletion of chemicals may then proceed. Space has been allocated for up to 260 chemicals in the lookup table. Row number 284 is the last row that may be used to add new chemicals. After the editing session is complete, the user must sort all the data in the lookup table (except the column headers) in ascending order by CAS number. After sorting is complete, the worksheet should again be protected (sealed). 59 SECTION 4 SOIL GAS MODEL APPLICATION Two additional models have been added to allow the user to input measured soil gas concentration and sampling depth data directly into the spreadsheet. These models eliminate the need for theoretical partitioning of a total volume soil concentration or a groundwater concentration into discrete phases. This section provides instructions for using the soil gas models. 4.1 RUNNING THE MODELS Two models are provided as MICROSOFT EXCEL spreadsheets. The screening-level model is titled SG-SCREEN.xls (EXCEL). The advanced model is titled SG-ADV.xls. Both the screening-level and advanced models allow the user to calculate steady-state indoor air concentrations and incremental risks from user-defined soil gas concentration data. The models do not allow for reverse-calculation of a risk-based soil or groundwater concentration. As with the soil and groundwater screening-level models, the SG-SCREEN model operates under the assumption that the soil column properties are homogeneous and isotropic from the soil surface to an infinite depth. In addition, the SG-SCREEN model uses the same default values for the building properties as the SL-SCREEN and GW-SCREEN models. The advanced model allows the user to specify up to three different soil strata from the bottom of the building floor in contact with the soil to the soil gas sampling depth. Finally, the advanced model allows the user to specify values for all of the model variables. To run the models, simply open the appropriate file within either MICROSOFT EXCEL worksheet. Each model is constructed of the following worksheets: 1. DATENTER (Data Entry Sheet) 2. CHEMPROPS (Chemical Properties Sheet) 3. INTERCALCS (Intermediate Calculations Sheet) 4. RESULTS (Results Sheet) 5. VLOOKUP (Lookup Tables) Each worksheet follows the form of the worksheets in the soil and groundwater models. See Section 4.2 for a description of each worksheet. 60 The DATENTER worksheet of each of the soil gas models is different than those of the soil and groundwater models. Figure 10 shows the DATA ENTER worksheet of the SG-ADV model. Note that there is no option for running the model to calculate a risk-based media concentration. As with the other models, the user enters the CAS number of the chemical of interest. This automatically retrieves the chemical and toxicological data for that chemical. The CAS number must match one of the chemicals listed in the VLOOKUP worksheet, or the message "CAS No. not found" will appear in the "Chemical" box. The user also has the opportunity to add new chemicals to the data base. Next, the user must enter a value for the soil gas concentration of the chemical of interest. The user may enter this value in units of :g/m3 or parts-per-million by volume (ppmv). If the soil gas concentration is entered in units of ppmv, the concentration is converted to units of :g/m3 by: C × MW Cg ' = g (33)R ×TS where Cg' = Soil gas concentration, :g/m3 Cg = Soil gas concentration, ppmv MW = Molecular weight, g/mol R = Gas constant (= 8.205 E-05 atm-m3/mol-oK) TS = System (soil) temperature, oK. In the soil gas models, the steady-state indoor air concentration is calculated by Equation 19 (i.e., Cbuilding = " Csource). The value of the vapor concentration at the source of emissions (Csource) is assigned the value of the user-defined soil gas concentration. The value of the steady-state attenuation coefficient (") in Equation 19 is calculated by Equation 13. Because no evaluation has been made of the extent of the source of emissions, steady-state conditions (i.e., a non-diminishing source) must be assumed. The SG-SCREEN model operates under the assumption of homogeneously distributed soil properties and isotropic conditions with respect to soil vapor permeability from the soil surface to an infinite depth. The SG-ADV model, on the other hand, allows the user to specify up to three different soil strata between the building floor in contact with the soil and the soil gas sampling depth. Soil properties within these three strata may be varied to allow for different diffusion resistances to vapor transport. 4.2 SOIL GAS SAMPLING In order to use the soil gas models, soil gas concentrations must be measured at one or more depths below ground surface (bgs). The user is advised to take samples directly under building slabs 61 Figure 10. SG-ADV Data Entry Worksheet 62 or basement floors when possible. This can be accomplished by drilling through the floor and sampling through the drilled hole. Alternatively, an angle-boring rig can be used to sample beneath the floor from outside the footprint of the building. When sampling directly beneath the floor is not possible, enough samples adjacent to the structure should be taken to adequately estimate an average concentration based on reasonable spatial and temporal scales. Soil gas measurements can be made using several techniques; however, active whole-air sampling methods and active or passive sorbent sampling methods are usually employed. Typically, a whole-air sampling method is used whereby a non-reactive sampling probe is inserted into the soil to a prescribed depth. This can be accomplished manually using a "slam bar," or a percussion power drill, or the probe can be inserted into the ground using a device such as a Geoprobe.  The Geoprobe device is attached to the rear of a specially customized vehicle. In the field, the rear of the vehicle is placed over the sample location and hydraulically raised on its base. The weight of the vehicle is then used to push the sampling probe into the soil. A built-in hammer mechanism allows the probe to be driven to predetermined depths up to 50 feet depending on the type of soil encountered. Soil gas samples can be withdrawn directly from the probe rods, or flexible tubing can be connected to the probe tips at depth for sample withdrawal. Whole-air sampling is typically accomplished using an evacuated Summa or equivalent canister, or by evacuation to a Tedlar bag. Normal operation includes the use of an in-line flow controller and a sintered stainless steel filter to minimize particles becoming entrained in the sample atmosphere. For a 6-liter Summa canister, a normal sampling flow rate for a 24-hr integrated sample might be on the order of 1.5 ml/min; however, higher sampling rates can be used for grab samples. The sampling rate chosen, however, must not be so high as to allow for ambient air inleakage between the annulus of the probe and the surrounding soils. Depending on the target compounds, excessive air inleakage can dilute the sample (in some cases below the analytical detection limits). One way to check for inleakage is to test an aliquot of the sample gas for either nitrogen or oxygen content before the sample is routed to the canister or Tedlar bag. To test for nitrogen in real- or near real-time requires a portable gas chromatograph/mass spectrometer (GC/MS). A portable oxygen meter, however, can be used to test for sample oxygen content in real-time with a typical accuracy of one-half of one percent. If air inleakage is detected by the presence of excessive nitrogen or oxygen, the seal around the sample probe at the soil surface as well as all sampling equipment connections and fittings should be checked. Finally, the flow rate may need to be reduced to decrease or eliminate the air inleakage. The collection and concentration of soil gas contaminants can be greatly affected by the components of the sampling system. It is imperative to use materials that are inert to the contaminants of concern. Areas of sample collection that need particular attention are: • The seal at the soil surface around the sample probe • Use of a probe constructed of stainless steel or other inert material • Minimization of the use of porous or synthetic materials (i.e., PTFE, rubber, or most plastics) that may adsorb soil gas and cause cross-contamination 63 • Purging of the sample probe and collection system before sampling • Leak-check of sampling equipment to reduce air infiltration • Keeping the length of all sample transfer lines as short as possible to minimize condensation of extracted gas in the lines. The choice of analytical methods for whole-air soil gas sampling depends on the contaminants of concern. Concentrations of volatile organic compounds (VOCs) in the soil gas are typically determined using EPA Method TO-14 or TO-15. In the case of semi-volatile compounds, an active sorbent sampling methodology can be used. In this case, a low-volume sampling pump is normally used to withdraw the soil gas, which is then routed to a polyurethane foam (PUF) plug. Vapor concentrations of semi-volatile contaminants sorbed to the PUF are then determined using EPA Method TO-10. The active soil gas sampling equipment can be assembled to allow for both canister sampling for volatiles and PUF sampling for semi-volatiles. Passive sorbent sampling involves burial of solid sorbent sampling devices called cartridges or cassettes to a depth of normally 5 feet or less. The cassettes may be configured with one or more sorbents depending on the list of target analytes, and are typically left in-ground for 72 to 120 hours or longer. During this time period, the vapor-phase soil gas contaminants pass through the cassette and are adsorbed as the soil gas moves toward the soil surface by diffusion and/or convection. Analytical methods for sorbent sampling depend on the target analytes and the sorbent used and may include EPA Method TO-10 or a modified EPA Method TO-1. Vapor-phase concentrations for some solid sorbent sampling systems are determined using the total mass of each contaminant recovered, the time in-ground, the cross-sectional area of the cassette, the diffusivity of the compound in air, and a quasi-empirical adsorption rate constant. Recent EPA technology verification reports produced by the EPA National Exposure Research Laboratory (EPA 1998, 1998a) concluded, at least for two such systems, that the sorbent methodologies accurately accounted for the presence of most of the soil gas contaminants in the studies. Further, the reports concluded that the sorbent systems showed detection of contaminants at low concentrations not reported using an active whole-air sampling system. For one system, however, it was noted that as the vapor concentrations reported for the whole-air sampling system increased by 1 to 4 orders-of-magnitude, the associated concentrations reported for the sorbent system increased only marginally. Perhaps the best use of such passive sorbent sampling methods is to help confirm which contaminants are present in the soil gas and not necessarily contaminant concentrations. An excellent discussion of soil gas measurement methods and limitations can be found in the ASTM Standard Guide for Soil Gas Monitoring in the Vadose Zone D5314-92e1. ASTM Standard Guides are available from the ASTM website at: http://www.astm.org. In addition, soil gas measurement method summaries can be found in the EPA Standard Operating Procedures for Soil Gas Sampling (SOP No. 2042) developed by the EPA Environmental Response 64 Team (ERT) in Edison, New Jersey. This document can be downloaded from the ERT Compendium of Standard Operating Procedures at the following website: http://www.ert.org/media_resrcs/media_resrcs.asp. Data Quality and Data Quality Objectives The results of soil gas sampling must meet the applicable requirements for data quality and satisfy the data quality objectives of the study for which they are intended. Data quality objectives are qualitative and quantitative statements derived from the data quality objectives process that clarify study objectives, define the appropriate type of data, and specify the tolerable levels of potential decision errors that will be used to support site decisions. Data quality objectives are formulated in the first phase of a sampling project. In the second phase of the project, a Quality Assurance Project Plan (QAPP) translates these requirements into measurement performance specifications and quality assurance/quality control procedures to provide the data necessary to satisfy the user's needs. The QAPP is the critical planning document for any environmental data collection operation because it documents how quality assurance and quality control activities will be implemented during the life of the project. Development of the data quality objectives and the QAPP for soil gas sampling should follow the guidance provided by EPA's Quality Assurance Division of the Office of Research and Development. Guidance documents concerning the development and integration of the data quality objectives and the QAPP can be obtained from the EPA website at: http://epa.gov/ncerqa/qa/qa_docs.html. In addition to the above guidance, the EPA Regional Office and/or other appropriate regulatory agency should be consulted concerning specific sampling requirements. 4.3 ASSUMPTIONS AND LIMITATIONS OF THE SOIL GAS MODEL As discussed previously, the soil gas models operate under the assumption of steady-state conditions. This means that enough time has passed for the vapor plume to have reached the building of interest directly above the source of contamination and that the vapor concentrations have reached their maximum values. Depending on the depth at which the soil gas is sampled, diffusion of the soil gas toward the building is a function of the soil properties between the building floor in contact with the soil and the sampling depth. Convection of the soil gas into the structure is a function of the building properties and the effective soil vapor permeability. Assumptions and limitations of the soil gas models are the same as those in Section 2.11 with the exception of the source vapor concentration that is determined empirically through soil gas sampling. The user should also recognize the inherent limitations of soil gas sampling. First, the geologic variability of the subsurface may be considerable. This may be especially problematic for 65 shallow soil gas sampling because soil moisture content can vary widely as a function of precipitation events and surface runoff. The soil moisture content has an exponential effect on the rate of vapor diffusion. Transformation processes such as biodegradation can also occur in shallow subsurface soils. In some cases, only a relatively thin stratum of bioactive soil can greatly reduce the emission flux toward the soil surface. Finally, subsurface phase equilibria is a dynamic process resulting in varying vapor-phase concentrations over time at the same sampling location and depth. These factors can result in significant differences in measured soil gas concentrations over relatively small spatial and temporal scales. For these reasons, the planning phase of the soil gas-sampling program should carefully consider the inherent uncertainties in site-specific sampling and analytical data. In the final analysis, the extent of soil gas sampling is a trade-off between sampling costs and the degree of certainty required in the soil gas concentration data. 66 SECTION 5 ASSUMPTIONS AND LIMITATIONS OF THE J&E MODEL The J&E Model is a one-dimensional analytical solution to diffusive and convective transport of vapors into indoor spaces. The model is formulated as an attenuation factor that relates the vapor concentration in the indoor space to the vapor concentration at the source. It was developed for use as a screening level model and consequently is based on a number of simplifying assumptions regarding contaminant distribution and occurrence, subsurface characteristics, transport mechanisms, and building construction. EPA is suggesting that the J&E Model be used at Resource Conservation and Recovery Act (RCRA) Corrective Action Sites, Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)/Superfund Sites, and voluntary cleanup sites. EPA is not recommending that the J&E Model be used for sites contaminated with petroleum products if the products were derived from Underground Storage Tanks. The J&E Model does not account for contaminant attenuation (biodegradation, hydrolysis, sorption, and oxidation/reduction). Attenuation is potentially a significant concern for these type of sites. EPA is recommending that investigators use OSWER Directive 9610.17: Use of Risk Based Decision-Making in UST Corrective Action Programs to evaluate these types of sites. The J&E Model as implemented by EPA assumes homogeneous soil layers with isotropic properties that characterize the subsurface. The first tier spreadsheet versions allow only one layer; the advanced spreadsheet versions allow up to three layers. Sources of contaminants that can be modeled include dissolved, sorbed, or vapor sources where the concentrations are below the aqueous solubility limit, the soil saturation concentration, and/or the pure component vapor concentration. The contaminants are assumed to be homogeneously distributed at the source. All but one of the spreadsheets assumes an infinite source. The exception is the advanced model for a bulk soil source, which allows for a finite source. For the groundwater and bulk soil models, the vapor concentration at the source is calculated assuming equilibrium partitioning. Vapor from the source is assumed to diffuse directly upward (one-dimensional transport) through uncontaminated soil (including an uncontaminated capillary fringe if groundwater is the vapor source) to the base of a building foundation, where convection carries the vapor through cracks and openings in the foundation into the building. Both diffusive and convective transport processes are assumed to be at steady state. Neither sorption nor biodegradation is accounted for in the transport of vapor from the source to the base of the building. The assumptions described above and in Table 12 suggest a number of conditions that preclude the use of the Non-NAPL Models as implemented by EPA. These conditions include: 67 TABLE 12. ASSUMPTIONS AND LIMITATIONS OF THE VAPOR INTRUSION MODEL Assumption Implication Field Evaluation Contaminant No contaminant free-liquid/precipitate phase present J&E Model not representative of NAPL partitioning from source NAPL or not at site–easier to evaluation for floating product or soil contamination sites. Most DNAPL sites with DNAPL below the water table defy easy characterization. Contaminant is homogeneously distributed within the zone of contamination No contaminant sources or sinks in the building. Indoor sources of contaminants and/or sorption of vapors on materials may confound interpretation of results. Survey building for sources, assessment of sinks unlikely Equilibrium partitioning at contaminant source. Groundwater flow rates are low enough so that there are no mass transfer limitations at the source. Not likely Chemical or biological transformations are not significant (model will predict more intrusion) Tendency to over predict vapor intrusion for degradable compounds From literature Subsurface Characteristics Soil is homogeneous within any horizontal plane Stratigraphy can be described by horizontal layers (not tilted layers) Observe pattern of layers and unconformities Note: In simplified J&E Model layering is not considered All soil properties in any horizontal plane are homogeneous The top of the capillary fringe must be below the bottom of the building floor in contact with the soil. EPA version of JE Model assumes the capillary fringe is uncontaminated. Transport Mechanisms One-dimensional transport Source is directly below building, stratigraphy does not influence flow direction, no effect of two-or three-dimensional flow patterns. Observe location of source, observe stratigraphy, pipeline conduits, not likely to assess two-and three- dimensional pattern. Two separate flow zones, one diffusive one convective. Vapor-phase diffusion is the dominant mechanism for transporting contaminant vapors from contaminant sources located away from the foundation to the soil region near the foundation No diffusion (dispersion) in the convective flow zone. Plug flow in convective zone Neglects atmospheric pressure variation effects, others? Not likely Not likely (continued) 68 Assumption Implication Field Evaluation Straight-line gradient in diffusive flow zone. Inaccuracy in flux estimate at match point between diffusive and convective sections of the model. Not likely Diffusion through soil moisture will be insignificant (except for compounds with very low Henry’s Law Constant Transport through air phase only. Good for volatiles. Only low volatility compounds would fail this and they are probably not the compounds of concern for vapor intrusion From literature value of Henry’s Law Constant. Convective transport is likely to be most significant in the region very close to a basement, or a foundation, and vapor velocities decrease rapidly with increasing distance from a structure Not likely Vapor flow described by Darcy’s law Porous media flow assumption. Observations of fractured rock, fractured clay, karst, macropores, preferential flow channels. Steady State convection Flow not affected by barometric pressure, infiltration, etc. Not likely Uniform convective flow near the foundation Flow rate does not vary by location Not likely Uniform convective velocity through crack or porous medium No variation within cracks and openings and constant pressure field between interior spaces and the soil surface Not likely Significant convective transport only occurs in the vapor phase Movement of soil water not included in vapor impact Not likely All contaminant vapors originating from directly below the basement will enter the basement, unless the floor and walls are perfect vapor barriers. (Makes model over est. vapors as none can flow around the building) Model does not allow vapors to flow around the structure and not enter the building Not likely Contaminant vapors enter structures primarily through cracks and openings in the walls and foundation Flow through the wall and foundation material itself neglected Observe numbers of cracks and openings. Assessment of contribution from construction materials themselves not likely • The presence or suspected presence of residual or free-product non-aqueous phase liquids (LNAPL, DNAPL, fuels, solvents, etc.) in the subsurface. • The presence of heterogeneous geologic materials (other than the three layers allowed in the advanced spreadsheets) between the vapor source and building. The J&E Model does not apply to geologic materials that are fractured, contain macropores or other preferential pathways, or are composed of karst. 69 • Sites where significant lateral flow of vapors occurs. These can include geologic layers that deflect contaminants from a strictly upward motion and buried pipelines or conduits that form preferential paths. Significantly different permeability contrasts between layers are likely to cause lateral flow of vapors. The model assumes the source of contaminants is directly below the potential receptors. • Very shallow groundwater where the building foundation is wetted by the groundwater. • Very small building air exchange rates (e.g., <0.25/h) • Buildings with crawlspace structures or other significant openings to the subsurface (e.g., earthen floors, stone buildings, etc.). The EPA spreadsheet only allows for either slab on grade or basement construction. • Contaminated groundwater sites with large fluctuations in the water table elevation. In these cases, the capillary fringe is likely to be contaminated; whereas in the groundwater source spreadsheets, the capillary fringe is assumed to be uncontaminated. In theory the above limitations are readily conceptualized, but in practice the presence of these limiting conditions may be difficult to verify even when extensive site characterization data are available. Conditions that are particularly difficult to verify in the field include the presence of residual non-aqueous phase liquids (NAPLs) in the unsaturated zone and the presence and influence of macropores, fractures and other preferential pathways in the subsurface. Additionally, in the initial stages of evaluation, especially at the screening level, information about building construction and water table fluctuations may not be available. Even the conceptually simple assumptions (e.g., one- dimensional flow, lack of preferential pathways) may be difficult to assess when there are little site data available. The vapor equilibrium models employed to estimate the vapor concentration at the source of soil contamination is applicable only if "low" concentrations of the compound(s) are sorbed to organic carbon in the soil, dissolved in soil moisture, and present as vapor within the air-filled soil pores (i.e., a three-phase system). The vapor equilibrium models do not account for a residual phase NAPLs. If residual phase contaminants are present in the soil column, the user is referred to either the NAPL-SCREEN or NAPL-ADV model (Appendix A), as appropriate. In the case of contaminated groundwater, the vapor equilibrium model operates under the assumption that the contaminant is present at levels below the water solubility limit. If the user- defined soil concentration is greater than the soil saturation concentration (Csat) or if the groundwater concentration is greater than the solubility limit (S), the equilibrium vapor concentration will be calculated at the value of Csat or S as appropriate. 70 The user is also reminded that when estimating a risk-based soil concentration, the model will compare the calculated soil concentration with the soil saturation concentration above which a residual phase is likely to occur. The soil saturation concentration (Csat) is calculated as in U.S. EPA (1996a and b). If the risk-based concentration is greater than the saturation concentration and the contaminant is a liquid or gas at the soil temperature, the final soil concentration will be set equal to the soil saturation concentration. This tends to eliminate the possibility of allowing a liquid residual phase to exist within the soil column, which may leach to the water table. If the risk-based soil concentration is greater than Csat and the contaminant is a solid, the contaminant is not of concern for the vapor intrusion pathway. Likewise, the groundwater models will compare the calculated risk-based groundwater concentration to the aqueous solubility limit of the compound. If the risk-based groundwater concentration is greater than the solubility limit, the contaminant is not of concern for the vapor intrusion pathway. Finally, it should be recognized that the procedures used to estimate both the soil saturation concentration and the aqueous solubility limit do not consider the effects of multiple contaminants. The estimated values, therefore, may be artificially high such that a residual phase may actually exist at somewhat lower concentrations. The procedures used to estimate the soil vapor permeability of the soil stratum in contact with the building floor and walls assume isotropic soils and steady-state soil moisture content. In addition, the calculations do not account for preferential vapor pathways due to soil fractures, vegetation root pathways, or the effects of a gravel layer below the floor slab or backfill. These items may act to increase the vapor permeability of in situ soils. If in situ pneumatic tests are used to measure site vapor permeability, care must be taken to ensure adequate sampling to reduce the possibility of missing important soil structure effects due to anisotropy. Single-point in situ pneumatic tests are typically conducted by measuring the pressure in a probe as a metered flow of air is passed through the probe and into the soil. Garbesi et al. (1996), however, demonstrated that soil vapor permeability increases with the sampling length scale. Using a dual-probe dynamic pressure sampling apparatus, Garbesi et al. (1996) demonstrated that the average soil vapor permeability typically increases up to a constant value as the distance between the source probe and detector probe increases. On a length scale typical of a house (3 to 10 m), use of the dual-probe sampling technique found that the soil permeability was approximately 10 to 20 times higher than that measured by the single-point method. Although arguably the most accurate means of determining in situ soil vapor permeability, the techniques of Garbesi et al. (1996) are complex and require specialized equipment. Another method for determining the intrinsic permeability of soil is to conduct empirical measurements of the saturated hydraulic conductivity (Ks). These data are then input into Equation 71 26. The resulting value of ki is then multiplied by the relative air permeability (krg) calculated by Equation 27 to yield the effective air permeability of the soil. Estimation of the rise of the capillary zone is based on the equation for the rise of a liquid in a capillary tube. The procedure assumes that the interstitial space between the soil particles is equivalent to the capillary tube diameter and that the resulting rise of water occurs under steady-state soil column drainage conditions. In actuality, the height of the capillary zone is uneven or fingered due to the variation in the actual in situ particle size distribution. In addition, the groundwater models do not account for the episodic rise and fall of the water table or the capillary zone due to aquifer recharge and discharge. As constructed, the groundwater models do not allow the top of the capillary zone to be above the bottom of the building floor in contact with the soil. The user should be aware, however, that in reality the top of the capillary zone may rise to levels above the floor in some cases. Diffusion across the capillary zone is estimated based on lumping vapor and aqueous-phase diffusion together within the calculation of the effective diffusion coefficient. To allow for vapor- phase diffusion within the capillary zone, the air-filled soil pores must be connected. In reality, the capillary zone may be comprised of a tension-saturated zone immediately above the water table and the deep portion of the vadose zone within which the soil water content is strongly dependent on the pressure head. Diffusion across the tension-saturated zone is dominated by liquid-phase diffusion, which is typically four orders of magnitude less than vapor-phase diffusion. Therefore, a large concentration gradient may exist between the top of the water table and the top of the tension- saturated zone (McCarthy and Johnson, 1993). Lumping vapor and aqueous-phase diffusion together is a less-intensive, although less- rigorous, method for estimating the effective diffusion coefficient. The result is typically a higher effective diffusion coefficient relative to separate solutions for aqueous diffusion across the tension- saturated zone and both vapor and aqueous diffusion across the unsaturated portion of the vadose zone. To minimize the possible overestimation of the effective diffusion coefficient, the soil air- filled porosity within the capillary zone is estimated based on the air-entry pressure head, which corresponds with the water-filled porosity at which the interstitial air-filled pores first become connected. The user should be aware that this procedure is inherently conservative if a significant concentration gradient exists across the tension-saturated zone. This conservatism may be somewhat offset in that the model does not consider any episodic rise in the level of the water table. During such events, water that had previously been part of the saturated zone (and hence contain higher contaminant concentrations) is redistributed in the vadose zone resulting in temporary elevations in soil gas concentrations. The model assumes that all vapors from underlying soils will enter the building through gaps and openings in the walls, floor, and foundation. This implies that a constant pressure field is generated between the interior spaces and the soil surface and that the vapors are intercepted within the pressure field and transported into the building. This assumption is inherently conservative in 72 that it neglects periods of near zero pressure differentials (e.g., during mild weather when windows are left open). As with the estimation procedure for soil vapor permeability, the model assumes isotropic soils in the horizontal direction; vertical anisotropy is accounted for by a series of isotropic soil strata above the top of contamination. Soil properties within the zone of soil contamination are assumed to be identical to those of the soil stratum directly above the contamination and extend downward to an infinite depth. Solute transports by convection (e.g., water infiltration) and by mechanical dispersion are neglected. Transformation processes (e.g., biodegradation, hydrolysis, etc.) are also neglected. The J&E Model treats the entire building as a single chamber with instantaneous and homogeneous vapor dispersion. It therefore neglects contaminant sinks and the room-to-room variation in vapor concentration due to unbalanced mechanical and/or natural ventilation. 5.1 SOURCE VAPOR CONCENTRATION As applied in the accompanying spreadsheets, the vapor equilibrium model employed to estimate the vapor concentration at the source of soil contamination is applicable in the limit of "low" concentrations where compounds are sorbed to organic carbon in the soil, dissolved is soil moisture, and present as vapor within the air-filled soil pores (i.e., a three-phase system). The model does not account for a residual phase (e.g., NAPL). If residual phase contaminants are present in the soil column, the user is referred to either the NAPL-SCREEN or NAPL-ADV model, as appropriate. In the case of contaminated groundwater, the vapor equilibrium model operates under the assumption that the contaminant is present at levels below the water solubility limit. If the user- defined soil concentration is greater than the soil saturation concentration (Csat) or if the groundwater concentration is greater than the solubility limit (S), the equilibrium vapor concentration will be calculated at the value of Csat or S as appropriate. The user is also reminded that when estimating a risk-based soil concentration, the model will compare the calculated soil concentration with the soil saturation concentration above which a residual phase is likely to occur. The soil saturation concentration (Csat) is calculated as in U.S. EPA (1996a and b). If the risk-based concentration is greater than the saturation concentration and the contaminant is a liquid or gas at the soil temperature, the final soil concentration will be set equal to the soil saturation concentration. This tends to eliminate the possibility of allowing a liquid residual phase to exist within the soil column, which may leach to the water table. If the risk-based soil concentration is greater than Csat and the contaminant is a solid, the contaminant is not of concern for the vapor intrusion pathway. Likewise, the groundwater models will compare the calculated risk-based groundwater concentration to the aqueous solubility limit of the compound. If the risk-based groundwater 73 concentration is greater than the solubility limit, the contaminant is not of concern for the vapor intrusion pathway. Finally, it should be recognized that the procedures used to estimate both the soil saturation concentration and the aqueous solubility limit do not consider the effects of multiple contaminants. The estimated values, therefore, may be artificially high such that a residual phase may actually exist at somewhat lower concentrations. 5.2 SOIL VAPOR PERMEABILITY The procedures used to estimate the soil vapor permeability of the soil stratum in contact with the building floor and walls assumes isotropic soils and steady-state soil moisture content. In addition, the calculations do not account for preferential vapor pathways due to soil fractures, vegetation root pathways, or the effects of a gravel layer below the floor slab or backfill which may act to increase the vapor permeability with respect to in situ soils. If in situ pneumatic tests are used to measure site vapor permeability, care must be taken to ensure adequate sampling to reduce the possibility of missing important soil structure effects due to anisotropy. Single point in situ pneumatic tests are typically conducted by measuring the pressure in a probe as a metered flow of air is passed through the probe and into the soil. Garbesi et al. (1996), however, demonstrated that soil vapor permeability increases with the sampling length scale. Using a dual-probe dynamic pressure sampling apparatus, Garbesi et al. (1996) demonstrated that the average soil vapor permeability typically increases up to a constant value as the distance between the source probe and detector probe increases. On a length scale typical of a house (3 to 10 m) use of the dual-probe sampling technique found that the soil permeability was approximately 10 to 20 times higher than that measured by the single point method. Although arguably the most accurate means of determining in situ soil vapor permeability, the techniques of Garbesi et al. (1996) are complex and require specialized equipment. Another method for determining the intrinsic permeability of soil is to conduct empirical measurements of the saturated hydraulic conductivity (Ks). These data are then input into Equation 26. The resulting value of ki is then multiplied by the relative air permeability (krg) calculated by Equation 27 to yield the effective air permeability of the soil. 5.3 RISE OF AND DIFFUSION ACROSS THE CAPILLARY ZONE Estimation of the rise of the capillary zone is based on the equation for the rise of a liquid in a capillary tube. The procedure assumes that the interstitial space between the soil particles is equivalent to the capillary tube diameter and that the resulting rise of water occurs under steady-state soil column drainage conditions. In actuality, the height of the capillary zone is uneven or fingered due to the variation in the actual in situ particle size distribution. In addition, the groundwater 74 models do not account for the episodic rise and fall of the water table or the capillary zone due to aquifer recharge and discharge. As constructed, the groundwater models do not allow the top of the capillary zone to be above the bottom of the building floor in contact with the soil. The user should be aware, however, that in reality the top of the capillary zone might rise to levels above the floor in some cases. Diffusion across the capillary zone is estimated based on lumping vapor and aqueous-phase diffusion together within the calculation of the effective diffusion coefficient. To allow for vapor- phase diffusion within the capillary zone, the air-filled soil pores must be connected. In reality, the capillary zone may be comprised of a tension-saturated zone immediately above the water table and the deep portion of the vadose zone within which the soil water content is a strongly dependent on the pressure head. Diffusion across the tension-saturated zone is dominated by liquid-phase diffusion which is typically four orders of magnitude less than vapor-phase diffusion. Therefore, a large concentration gradient may exist between the top of the water table and the top of the tension- saturated zone (McCarthy and Johnson, 1993). Lumping vapor and aqueous-phase diffusion together is a less intensive, although less rigorous, method for estimating the effective diffusion coefficient. The result is typically a higher effective diffusion coefficient relative to separate solutions for aqueous diffusion across the tension- saturated zone and both vapor and aqueous diffusion across the unsaturated portion of the vadose zone. To minimize the possible over estimation of the effective diffusion coefficient, the soil air- filled porosity within the capillary zone is estimated based on the air-entry pressure head, which corresponds with the water-filled porosity at which the interstitial air-filled pores first become connected. The user should be aware that this procedure is inherently conservative if a significant concentration gradient exists across the tension-saturated zone. This conservatism may be somewhat offset in that the model does not consider any episodic rise in the level of the water table. During such events, water which had previously been part of the saturated zone (and hence contain higher contaminant concentrations) is redistributed in the vadose zone resulting in temporary elevations in soil gas concentrations. 5.4 DIFFUSIVE AND CONVECTIVE TRANSPORT INTO THE STRUCTURE The following is a discussion of the major assumptions and limitations of the J&E Model for diffusive and convective vapor transport into buildings. The model assumes that all vapors from underlying soils will enter the building through gaps and openings in the walls, floor, and foundation. This implies that a constant pressure field is generated between the interior spaces and the soil surface and that the vapors are intercepted within the pressure field and transported into the building. This assumption is inherently conservative in that it neglects periods of near zero pressure differentials (e.g., during mild weather when windows are left open). 75 As with the estimation procedure for soil vapor permeability, the model assumes isotropic soils in the horizontal direction; vertical anisotropy is accounted for by a series of isotropic soil strata above the top of contamination. Soil properties within the zone of soil contamination are assumed to be identical to those of the soil stratum directly above the contamination and extend downward to an infinite depth. Solute transports by convection (e.g., water infiltration) and by mechanical dispersion are neglected. Transformation processes (e.g., biodegradation, hydrolysis, etc.) are also neglected. An empirical field study (Fitzpatrick and Fitzgerald, 1997) indicated that the model may be overly conservative for nonchlorinated species (e.g., benzene, toluene, ethylbenzene and xylene) but in some cases, may underpredict indoor concentrations for chlorinated species. The authors contribute the likely cause for this discrepancy to the significant biodegradation of the nonchlorinated compounds. The J&E Model treats the entire building as a single chamber with instantaneous and homogeneous vapor dispersion. It therefore neglects contaminant sinks and the room-to-room variation in vapor concentration due to unbalanced mechanical and/or natural ventilation. Finally, convective vapor flow from the soil matrix into the building is represented as an idealized cylinder buried below grade. This cylinder represents the total area of the structure below the soil surface (walls and floor). The total crack or gap area is assumed to be a fixed fraction of this area. Because of the presence of basement walls, the actual vapor entry rate is expected to be 50 to 100 percent of that provided by the idealized geometry (Johnson and Ettinger, 1991). 76 SECTION 6 INTERPRETATION OF RESULTS The models described herein are theoretical approximations of complex physical and chemical processes and as such should not be used in a deterministic fashion (i.e., to generate a single outcome). At the least, a range of outcomes should be explored focusing on the most sensitive model input variables. In general, using the default values for input variables will result in higher indoor air concentrations and thus higher incremental risks or lower risk-based media concentrations. With a realistic range of outcomes, the risk manager may assess the uncertainty in the model predictions. From a conceptual point of view, the vapor intrusion model provides a theoretical description of the processes involved in vapor intrusion from subsurface soils or groundwater into indoor structures. A combination of modeling and sampling methods is also possible to reduce the uncertainty of the calculated indoor air concentrations. Typically this involves field methods for measuring soil gas very near or below an actual structure. It should be understood, however, that soil gas sampling results outside the footprint of the building may or may not be representative of the soil gas concentrations directly below the structure. For solid building floors in contact with the soil (e.g., concrete slabs), the soil gas directly beneath the floor may be considerably higher than that adjacent to the structure. This is typically due to a vapor pooling effect underneath the near impermeable floor. Once a representative average concentration is determined, all vapor directly below the areal extent of the building is presumed to enter the structure. The soil gas concentration, along with the building ventilation rate and the soil gas flow rate into the building, will determine the indoor concentration. When using the soil gas models, it must be remembered that no analysis has been made concerning the source of contamination. Therefore, the calculated indoor concentration is assumed to be steady-state. The procedures described in API (1998) can be used to calibrate the diffusion transport considerations of the J&E Model as well as for calibrating the Model for transformation processes (e.g., biodegradation). The reader is also referred to U.S. EPA (1992) for a more detailed discussion of applying soil gas measurements to indoor vapor intrusion. Finally, calibration and verification of the model have been limited due to the paucity of suitable data. Research is needed to provide spatially and temporally correlated measurements during different seasons, at different locations, with different buildings, and over a range of different contaminants such that the accuracy of the model may be determined. Appendix E contains bibliography and references. 77 APPENDIX A USER’S GUIDE FOR NON-AQUEOUS PHASE LIQUIDS A-1 Purpose The NAPL-SCREEN and NAPL-ADV models are designed to forward calculate incremental cancer risks or noncarcinogenic hazard quotients due to subsurface soil vapor intrusion into buildings. The models are specifically designed to handle nonaqueous phase liquids or solids in soils. The user may specify up to 10 soil contaminants, the concentrations of which form a residual phase mixture. A residual phase mixture occurs when the sorbed phase, aqueous phase, and vapor phase of each chemical have reached saturation in soil. Concentrations above this saturation limit for all of the specified chemicals of a mixture will result in a fourth or residual phase (i.e., nonaqueous phase liquid or solid). Other vapor intrusion models (SL-SCREEN, SL-ADV, SG-SCREEN, SG-ADV, GW­ SCREEN, and GW-ADV) handled only a single contaminant and only when the soil concentration was at or below the soil saturation limit (i.e., a three-phase system). Use of these models when a residual phase is present, results in an overprediction of the soil vapor concentration and subsequently the building vapor concentration. Residual Phase Theory The three-phase system models estimate the equilibrium soil vapor concentration at the emission source (Csource) using the procedures from Johnson et al. (1990): ' Csource = H TSCRρb (1)' θw + Kd ρb + H TSθa where: Csource = Vapor concentration at the source of contamination, g/cm3 ’ H TS = Henry’s law constant at the soil temperature, dimensionless CR = Initial soil concentration, g/g ρb = Soil dry bulk density, g/cm3 θw = Soil water-filled porosity, cm3/cm3 Kd = Soil-water partition coefficient, cm3/g ( = Koc × foc) θa = Soil air-filled porosity, cm3/cm3 Koc = Soil organic carbon partition coefficient, cm3/g foc = Soil organic carbon weight fraction. In Equation 1, the equilibrium vapor concentration is proportional to the soil concentration up to the soil saturation limit. When a residual phase is present, however, the vapor concentration is independent of the soil concentration but proportional to the mole fraction of the individual component of the residual phase mixture. In this case, the equilibrium vapor concentration must be calculated numerically for a series of time-steps. For each time-step, the mass of each constituent that is volatilized is calculated using Raoult’s law and the appropriate mole fraction. At the end of each time-step, the total mass lost is subtracted from the initial mass and the mole fractions are recomputed for the next time-step. A-2 The NAPL-SCREEN and NAPL-ADV models use the procedures of Johnson et al. (2001) to calculate the equilibrium vapor concentration at the source of emissions for each time-step. Within each model, the user-defined initial soil concentration of each component in the mixture is checked to see if a residual phase is present. This is done by calculating the product of the activity coefficient of component i in water (αi) and the mole fraction of i dissolved in soil moisture (yi) such that: M iαiyi = [(Pi v (TS )θaV / RTS )+ (M H 2O /αi )+ (Kd ,iM soil /αiMWH 2O )δ (M H 2O )] (2) where: Mi = Initial moles of component i in soil, moles Pi v(TS) = Vapor pressure of i at the average soil temperature, atm θa = Soil air-filled porosity, cm3/cm3 V = Volume of contaminated soil, cm3 R = Ideal gas constant, 82.05 atm-cm3/mol-oK TS = Average soil temperature, oK OMH 2 = Total moles in soil moisture dissolved phase, moles αi = Activity coefficient of i in water, unitless Kd,i = Soil-water partition coefficient of i, cm3/g Msoil = Total mass of contaminated soil, g MWH2O = Molecular weight of water, 18 g/mol δ(MH 2 O) = 1 if MH 2 O > 0, and δ(MH 2 O) = 0 if MH 2 O = 0. If the sum of all the values of αiyi for all of the components of the mixture is less than 1, the mixture does not contain a residual phase and the models are not applicable. In such cases, the SL-SCREEN or SL-ADV model can be used to estimate the building concentration. Once it has been determined that a residual phase does exists, the mole fraction of each component (xi) is determined by iteratively solving Equations 3 and 4 subject to the constraint that the sum of all the mole fractions equals unity (Σxi = 1): Mi=xi [(Piv (TS )θaV / RTS )+ M HC +(M H 2O /αi )+(Kd ,iMsoil /αiMWH 2O )δ (M H 2O )] (3) and, HCMixi = M HC (4) A-3   where Mi HC is the number of moles of component i in residual phase and MHC is the total number of moles of all components in residual phase. The solution is simplified by assuming that MH 2 O is approximately equal to the number of moles of water in the soil moisture. With the mole fraction of each component at the initial time-step, the equilibrium vapor concentration at the source of emissions is calculated by Raoult’s law: v Csource = xiPi (TS )MWi (5)RTS where MWi is the molecular weight of component i (g/mol). At the beginning of each succeeding time-step, the number of moles of each chemical remaining in the soil from the previous time-step are again checked to see if a residual phase is present using Equation 2. When a residual phase is no longer present, the equilibrium vapor concentration at the source of emissions is calculated by: Csource =αi yiPiv (TS )MWi . (6)RTS Ancillary Calculations The activity coefficient of component i in water (αi) is estimated from its solubility. Because hydrocarbons are typically sparingly soluble in water, the following generalization has been applied to compounds that are liquid or solid at the average soil temperature: αi =(1/ yi )=(55.55 moles/L)MWi / Si (7) where Si is the solubility of component i (g/L). For gases at the average soil temperature, the corresponding relationship is: αi =(1/ yi )(1atm / Piv (TS ))= (55.55 moles/ L)(MWi (1 atm)/ SiPiv (TS )) . (8) Assuming that the vapor behaves as an ideal gas with a relatively constant enthalpy of vaporization between 70oF and the average soil temperature, the Claussius-Clapeyron equation can be used to estimate the vapor pressure at the desired temperature: Pv (TS ) = Pv (TR ) × exp   TB ×TR  1 − 1  ln Pv (TR )   (9)   (TB − TR  TS TR   PB  where: Pv(TS) = Vapor pressure at the desired temperature TS, atm Pv(TR) = Vapor pressure at the reference temperature TR, atm A-4     TB = Normal boiling point, oK TR = Vapor pressure reference temperature, oK TS = The desired temperature, oK PB = Normal boiling point pressure = 1 atm. Building Concentration The vapor concentration within the building or enclosed space (Cbuilding) is calculated using the steady-state solution of Johnson and Ettinger (1991) such that: Cbuilding =αCsource . (10) The steady-state attenuation coefficient (α) is calculated by:  eff AB  × exp Qsoil Lcrack    DT α =  Qbuilding LT   Dcrack Acrack  (11) exp Qsoil Lcrack  +  DT eff AB  +  DT eff AB   exp QsoilLcrack  −1     Dcrack Acrack   QbuildingLT   Qsoil LT   Dcrack Acrack   where: α = Steady-state attenuation coefficient, unitless DTeff = Total overall effective diffusion coefficient, cm2/s AB = Area of the enclosed space below grade, cm2 Qbuilding = Building ventilation rate, cm3/s LT = Source-building separation, cm Qsoil = Volumetric flow rate of soil gas into the enclosed space, cm3/s Lcrack = Enclosed space foundation or slab thickness, cm Acrack = Area of total cracks, cm2 Dcrack = Effective diffusion coefficient through the cracks, cm2/s. The reader is referred to Section 2.5 of this Guidance for a more detailed discussion of the derivation of Equation 11 and procedures for determining values for model input parameters. Except for the calculation of the equilibrium vapor concentration at the source of emissions, NAPL-SCREEN is identical to the three-phase model SL-SCREEN and NAPL-ADV is identical to the three-phase model SL-ADV. The NAPL-SCREEN and NAPL-ADV models explicitly solve for the time-averaged building concentration over the exposure duration using a forward finite-difference numerical approach. For each time-step δt: Mi (t +δt )= Mi (t )−δt(Cbuilding × Qbuilding / MWi ) (12) A-5 where Mi (t) is the number of moles of component i in soil at the previous time and Mi(t+δt) is the number of moles at the new time. The time-step interval is variable as a function of the percent of mass lost over the time-step. The user may specify a minimum and maximum percent loss allowed; these values are applied to the single component of the residual phase mixture with the highest mass loss rate during each time-step interval. If the user-specified maximum percent loss is exceeded, the next time-step interval is reduced by half; likewise, if the user-specified minimum percent loss is not achieved, the next time-step interval is increased by a factor of two. The instantaneous building concentration at time = t is calculated using Equation 10 for each time-step. The time-averaged building concentration is estimated using a trapezoidal approximation of the integral. Model Assumptions and Limitations The NAPL-SCREEN and NAPL-ADV models operate under the assumption that sufficient time has elapsed since the time of initial soil contamination for steady-state conditions to have been achieved. This means that the subsurface vapor plume has reached the bottom of the enclosed space floor and that the vapor concentration has reached its maximum value. An estimate of the time required to reach near steady-state conditions (Jss) can be made using the following equations from API (1998): τss ≅ RvθaLT 2 (13) Deff and, Rv = 1+θw +ρbKd (14)''θaH TS θaH TS and, θ 10 /3  D θ 10 /3 w  wDeff = Da a n2 +   H ' TS  n2 (15) where Rv is the unitless vapor phase retardation factor, LT is the source-building separation (cm), Deff is the effective diffusion coefficient (cm2/s), Da is the diffusivity in air (cm2/s), Dw is the diffusivity in water (cm2/s), and n is the soil total porosity (cm3/cm3). The NAPL-SCREEN and NAPL-ADV models are applicable only when the elapsed time since initial soil contamination meets or exceeds the value of Jss (see Using the Models). Emission source depletion is calculated by estimating the rate of vapor loss as a function of time such that the mass lost at each time-step is subtracted from a finite mass of contamination at the source. This requires the model user to estimate the dimensions of the emission source, e.g., the length, width, and thickness of the contaminated zone. The model should only be used, therefore, A-6 when the extent of soil contamination has been sufficiently determined. It should be noted that because the NAPL-SCREEN and NAPL-ADV models are one-dimensional, the areal extent of soil contamination (i.e., length × width) can be less than but not greater than the areal extent of the building floor in contact with the soil. Each model treats the contaminated zone directly below the building as a box containing a finite mass of each specified compound. The initial contamination contained within the box is assumed to be homogeneously distributed. After each time-step, the remaining contamination is assumed to be instantaneously redistributed within the box to homogeneous conditions. The diffusion path length from the top of contamination to the bottom of the enclosed space floor therefore remains constant with time. Use of this simplifying assumption means that the degree of NAPL soil saturation is not required in the calculation of the total overall effective diffusion coefficient (DTeff). As time proceeds, the concentration of the mixture of compounds within the soil column may reach the soil saturation limit. Below this point, a residual phase will cease to exist and the vapor concentration of each chemical will decrease proportional to its total volume soil concentration. Theoretically, the vapor concentration will decrease asymptotically, approaching but never reaching zero. Because of the nature of the numerical solution to equilibrium vapor concentration, however, compounds with high effective diffusion coefficients (e.g., vinyl chloride) may reach zero soil concentrations while other less volatile contaminants will not. If the initial soil concentrations are significantly higher than their respective values of the soil saturation concentration, a residual phase may persist up to the user-defined exposure duration. Model assumptions and limitations concerning vapor transport and vapor intrusion into buildings are those specified for the three-phase models. Using the Models Each model is constructed as a Microsoft Excel workbook containing five worksheets. The DATENTER worksheet is the data entry worksheet and also provides model results. The VLOOKUP worksheet contains the “Chemical Properties Lookup Table” with listed chemicals and associated chemical and toxicological properties. It should be noted that the toxicological properties for many of these chemicals were derived by route-to-route extrapolation. In addition, the VLOOKUP worksheet includes the “Soil Properties Lookup Table” containing values for model intermediate variables used in estimating the soil vapor permeability. The CHEMPROPS worksheet provides a summary of the chemical and toxicological properties of the soil contaminants selected by the user. In addition, the CHEMPROPS worksheet provides calculated values for the soil saturation concentration (Csat) and the time to reach steady-state conditions (Jss) once all required data are entered into the DATENTER worksheet. The INTERCALCS worksheet contains calculated values of intermediate model variables. Finally, the COMPUTE worksheet contains the numerical solutions for equilibrium vapor concentration and building vapor concentration as a function of time. A-7 Both models use the Microsoft SOLVER add-in algorithms to simultaneously solve Equations 3 and 4 for each of up to 10 chemicals specified by the user. In order to run NAPL­ SCREEN or NAPL-ADV, the SOLVER add-in must be loaded into EXCEL. The user is referred to the EXCEL instructions for loading the SOLVER add-in. On the DATENTER worksheet, the user may specify up to 10 soil contaminants by CAS number along with associated soil concentrations in units of mg/kg. The CAS number entered must match exactly one of the 93 chemicals listed in the VLOOKUP worksheet or the error message “CAS No. not found” will appear in the “Chemical” box. If the list of chemicals and concentrations entered does not constitute a residual phase, the error message in Figure 1 will appear after starting the model. Figure 1. Residual Phase Error Message Model Not Applicable! The mixture of compounds and concentrations listed does not include a residual phase. This model is not applicable! OK If this error message box appears, use either the SL-SCREEN or SL-ADV model to estimate subsurface vapor intrusion into the building. After starting the model calculations, other error message boxes may appear if data entry values are missing on the DATENTER worksheet or if entered values do not conform to model assumptions. If such an error message box appears, fill-in missing data or re-enter data as appropriate. If entered data values are outside the expected range or if text values are entered where numeric values are expected, the model calculation macro will be suspended and the run-time error message in Figure 2 will appear. Figure 2. Run-Time Error Message Microsoft Visual Basic Run-time error ‘13’ Type mismatch Continue End Debug Help Should this error message appear, click on the “End” button to terminate the macro and return to the DATENTER worksheet. At this point, the user should review all of the entered values and make the appropriate corrections. A-8 In addition to contaminant data, soil properties data, zone of contamination data, and exposure assumptions must also be specified in the DATENTER worksheet. Similar to the SL­ SCREEN three-phase model, the NAPL-SCREEN model allows for only one soil stratum between the top of contamination and the bottom of the building floor in contact with the soil. In addition, the NAPL-SCREEN model uses built-in default values for all building variables (e.g., building dimensions, air exchange rate, total crack area, etc.). These default values are for single-family detached residences; therefore, the NAPL-SCREEN model should only be used for the residential exposure scenario. The NAPL-ADV model, like the SL-ADV model, allows for up to three different soil strata between the top of contamination and the bottom of the building floor. In addition, the NAPL-ADV model allows the user to enter values for all model variables. This allows for the estimation of soil vapor intrusion into buildings other than single-family residences. For each model, the user must also enter the duration of the first (initial) time-step interval. The maximum and minimum change in mass for each time-step must also be specified. The values of the initial time-step interval, and the maximum and minimum change in mass are important. If these values are too low, the model will calculate very small increments in the mass lost over time which will greatly extend the run-time of the model. In general, if the concentrations of the least volatile chemicals in the mixture are well above their respective values of the soil saturation concentration, a relatively large initial time-step interval, and maximum and minimum change in mass should be specified (e.g., 4 days, 10%, and 5%, respectively). For comparison, the value of the soil saturation concentration (Csat) for each chemical specified by the user may be found in the CHEMPROPS worksheet after all data have been entered on the DATENTER worksheet. If, however, the soil concentrations of the most volatile constituents are very close to their respective saturation limits, large values of the initial time-step interval, and the maximum and minimum change in mass will result in the error message in Figure 3 after starting the model. Figure 3. Time-Step and Change in Mass Error Message The initial time-step, maximum and minimum change in mass values are too high for successful completion of the calculations. Reduce these values and re-run the model. OK Re-set Values! Should this error message occur, reduce the value of the initial time-step interval and the values of the maximum and minimum change in mass to smaller values and re-run the model. The error message will be repeated until the values of these variables are sufficiently small. A-9 After all required data are entered into the DATENTER worksheet, the model is run by clicking on the “Execute Model” button which will change from reading “Execute” to “Stand by...”. In addition, the message box in Figure 4 will appear keeping a running count of the number of residual phase time-step solutions achieved by the model. Figure 4. Progress of Calculations Message Box Progress of Calculations Number of residual phase time-step solutions: To stop calculations early, press CTRL + BREAK. 1 Each SOLVER trial solution can also be seen running in the status bar at the bottom of the screen. When the model is finished calculating, the “Execute Model” button will read “Done” and the Progress of Calculations message box in Figure 4 will disappear. The time-averaged building concentrations, incremental cancer risks, and/or hazard quotients will then be displayed under the “RESULTS” section of the DATENTER worksheet. In addition, an “X” will appear beside the calculated risk or hazard quotient of each contaminant for which a route-to-route extrapolation was employed. It should be noted that a route-to-route extrapolation was used for any chemical without a unit risk factor (URF) or a reference concentration (RfC). Therefore, the user should evaluate the resulting cancer risks and/or hazard quotients of such chemicals. Once a solution has been achieved and the user wishes to save the results, the file should be saved under a new file name. If the user wishes to delete all of the data previously entered on the DATENTER worksheet, this may be accomplished by clicking on the “Clear Data Entry Sheet” button. Stopping Calculations Early As mentioned previously, the user-defined values of the initial time-step interval, and the maximum and minimum change in mass should be chosen carefully. If the model run-time is excessive or if the user simply wishes to terminate the calculations, the model may be stopped by pressing CTRL + BREAK. If termination occurs in-between SOLVER solutions, the message box in Figure 5 will appear. A-10 Figure 5. Code Interruption Message Box Continue End Debug Help Microsoft Visual Basic Code execution has been interrupted If this message box appears, click on the “End” button to terminate the macro. If the termination occurs during a SOLVER solution, the message box in Figure 6 will appear. If this message box appears, click on the “Stop” button. This will stop the SOLVER solution but not the program macro. Depending on where in the macro code the interruption occurs, the model may continue to operate after clicking on the “Stop” button in Figure 6. If this happens, press CTRL + BREAK again. At this point, the message box in Figure 5 will appear; click on the “End” button to terminate the macro. Figure 6. Solver Interruption Message Box Continue Stop Save Scenario... Help Show Trial Solution Solver paused, current solution values displayed on worksheet At this point, the user may examine the model results up to the point of termination on the COMPUTE worksheet. The values of the “Change in mass”, the “Time-step interval”, and the “Cumulative time” should be examined to determine if changes are necessary in the values of the initial time-step interval, and the maximum and minimum change in mass. After these or any other values are changed on the DATENTER worksheet, the model may be re-run by clicking on the “Execute Model” button. Step-By-Step Procedures for Running the Models The following gives the step-by-step procedures for running either the NAPL-SCREEN or the NAPL-ADV model. A-11 1. On the DATENTER worksheet, enter the CAS number of each soil contaminant in the residual phase mixture (do not include dashes in the CAS numbers). After the CAS numbers have been entered, the respective chemical names will appear in the “Chemical” box. 2. On the DATENTER worksheet, enter the soil concentration of each contaminant in units of mg/kg as well as values for all remaining variables except the “Initial time-step”, the “Maximum change in mass”, and the “Minimum change in mass”. 3. On the CHEMPROPS worksheet, note the calculated values of the “Time to steady state” (Jss) for each contaminant. Calculated values of the time-averaged building concentration and associated risks for contaminants with values of Jss greater than the actual elapsed time since initial soil contamination will be artificially high. 4. On the CHEMPROPS worksheet, note the calculated values of the “Soil saturation concentration” (Csat) for each contaminant. Use these data to help determine appropriate user- defined values for the initial time-step, and the maximum and minimum change in mass. Typical values for these variables might be 2 days, 7%, and 4%, respectively, but may be considerably higher or lower depending on the number of chemicals in the analysis and the starting soil concentrations (see the discussion on page 8). 5. Click on the “Execute Model” button to begin the model calculations. If data are missing on the DATENTER worksheet, or entered values do not conform to model assumptions, an error message box will appear after the model is started informing the user of the type of error encountered. Enter the appropriate values on the DATENTER worksheet and re-run the model. Once the model has successfully started, note the number of residual phase time-step solutions achieved by the model in the Progress of Calculations message box (Figure 4). Use this information to help establish new values for the initial time-step interval and the maximum and minimum change in mass if the number of time-steps needs to be increased or decreased. 6. When the NAPL-SCREEN model has finished calculating, check column “O” on the COMPUTE worksheet to determine how many time-steps were calculated while a residual phase was present; one time-step is equal to one row (when using the NAPL-ADV model check column “P”). A residual phase is present when the value in column “O” or “P”, as appropriate, is equal to 1.000. In general, a greater number of time-steps means a more accurate estimate of the time-averaged building concentration. If the starting soil concentrations of the most volatile contaminants are very close to their respective values of Csat, a minimum of 5 to 10 time-steps should be calculated by the model. For all other cases, a reasonable number of time-steps is between 40 and 70. To increase the number of time-steps calculated by the model, decrease the values of the initial time-step interval and the maximum and minimum change in mass. The opposite is true when the number of time- steps is to be decreased. A-12 7. If the message box in Figure 1 appears after starting the model, the mixture of compounds and concentrations specified does not include a residual phase. Use the SL-SCREEN or SL-ADV model to calculate indoor air concentrations and risks for each contaminant separately. 8. If the message box in Figure 3 appears after starting the model, reduce the input values of the initial time-step, and maximum and minimum change in mass and re-run the model. 9. If the run-time of the model is excessive, terminate the model macro by pressing CTRL + BREAK (see the discussion under Stopping Calculations Early on pages 9 and 10). Examine the calculated values of the “Change in mass”, the “Time-step interval”, and the “Cumulative time” on the COMPUTE worksheet. Re-enter new lower values for the initial time-step interval, and the maximum and minimum change in mass and re-run the model. 10. After successful completion of a model run, note the calculated values of the “Time-averaged building concentration”, “Incremental cancer risk”, and/or “Hazard quotient” in the “RESULTS” section of the DATENTER worksheet. Also note for which contaminants a route-to-route extrapolation was employed. If the model results are to be retained, save the file under a new file name. Adding, Deleting or Revising Chemical Data Additional chemicals can be listed in the “Chemical Properties Lookup Table” within the VLOOKUP worksheet. To add, delete or revise chemicals, the VLOOKUP worksheet must be unprotected using the password “ABC” in capital letters. Row number 171 is the last row that may be used to add new chemicals. If new chemicals are added or chemicals deleted, the user must sort all the data in the “Chemical Properties Lookup Table” (except the column headers) in ascending order by CAS number. After sorting is complete, the worksheet should again be protected. A-13 APPENDIX B CHEMICAL PROPERTIES LOOKUP TABLE AND REFERENCES B-1 CA S N o . Ch e m i c a l Or g a n i c Ca r b o n Pa r t i t i o n Co e f f i c i e n t He n r y ' s L a w He n r y ' s L a w En t h a l p y o f Co n s t a n t a t Co n s t a n t V ap o r i z a t i o n a t Dif f u s i v i t y i n Dif f u s i v i t y Re f e r e n c e Re f e r e n c e No r m a l Cr i t i c a l th e N o r m a l Un i t R i s k Re f e r e n c e Vapor Ai r in W a t e r Te m p e r a t u r e Te m p e r a t u r e Bo i l i n g P o i n t Te m p e r a t u r e Bo i l i n g P o i n t Fa c t o r Co n c e n t r a t i o n De n s i t y , Pressure Pu r e Co m p o n e n t Wa t e r So l u b i l i t y He n r y ' s La w Co n s t a n t Ph y s i c a l Sta t e a t so i l T e m p Molecular Weight URF extrapolated Rfc extrapolated K oc D a D w S H ' H T R T B T C de l t a H v,b UR F RfC r i VP Mw (c m 3 /g ) (c m 2 /s ) (c m 2 /s ) (m g / L ) (u n i t l e s s ) (a t m - m 3 /m o l ) (o C) (o K) (o K) (c a l / m o l ) (u g / m 3 )-1 (m g / m 3 ) (g / c m 3 ) (S , L , G ) (mm Hg) (g/mole) (X) (X) 74 8 7 3 Me t h y l c h l o r i d e ( c h l o r o m e 2.1 2 E + 0 0 2 1.2 6 E - 0 1 2 6. 5 0 E - 0 6 2 5.3 3 E + 0 3 3 3.6 1 E - 0 1 3 8.8 0 E - 0 3 25 24 9 . 0 0 4 41 6 . 2 5 4 5.1 1 E + 0 3 4 1.0 0 E - 0 6 3 9.0 0 E - 0 2 3 0.9 1 5 9 8 L 4.30E+03 5.05E+01 3 74 9 0 8 Hy d r o g e n c y a n i d e 3.8 0 E + 0 0 2 1.9 3 E - 0 1 2 2. 1 0 E - 0 5 2 1.0 0 E + 0 6 3 5. 4 4 E - 0 3 3 1.3 3 E - 0 4 25 29 9 . 0 0 4 45 6 . 7 0 4 6.6 8 E + 0 3 7 0. 0 0 E + 0 0 3 3.0 0 E - 0 3 3 0.6 8 7 6 4 L 7.42E+02 2.70E+01 3 74 9 5 3 Me t h y l e n e br o m i d e 1.2 6 E + 0 1 2 4.3 0 E - 0 2 2 8. 4 4 E - 0 6 2 1.1 9 E + 0 4 3 3. 5 2 E - 0 2 3 8.5 9 E - 0 4 25 37 0 . 0 0 4 58 3 . 0 0 6 7.8 7 E + 0 3 4 0. 0 0 E + 0 0 3 3.5 0 E - 0 2 3 2.4 9 6 9 4 L 4.44E+01 1.74E+02 3 X 75 0 0 3 Ch l o r o e t h a n e ( e t h y l c h l o r i 4.4 0 E + 0 0 2 2.7 1 E - 0 1 2 1. 1 5 E - 0 5 2 5.6 8 E + 0 3 3 3. 6 1 E - 0 1 3 8.8 0 E - 0 3 25 28 5 . 3 0 4 46 0 . 4 0 4 5.8 8 E + 0 3 4 8.2 9 E - 0 7 3 1.0 0 E + 0 1 3 0.3 2 4 2 8 L 1.01E+03 6.45E+01 3 X 75 0 1 4 Vin y l c h l o r i d e ( c h l o r o e t h e n 1.8 6 E + 0 1 1 1.0 6 E - 0 1 1 1. 2 3 E - 0 5 1 8.8 0 E + 0 3 3 1.1 0 E + 0 0 3 2.6 9 E - 0 2 25 2.5 9 E + 0 2 1 4.3 2 E + 0 2 1 5.2 5 E + 0 3 1 8.8 0 E - 0 6 3 1.0 0 E - 0 1 3 9.1 1 E - 0 1 4 G 2.98E+03 6.25E+01 3 75 0 5 8 Ac e t o n i t r i l e 4.2 0 E + 0 0 2 1.2 8 E - 0 1 2 1. 6 6 E - 0 5 2 1.0 0 E + 0 6 3 1. 4 2 E - 0 3 3 3.4 5 E - 0 5 25 35 4 . 6 0 4 54 5 . 5 0 4 7.1 1 E + 0 3 4 0. 0 0 E + 0 0 3 6.0 0 E - 0 2 3 0.7 8 5 7 4 L 9.11E+01 4.11E+01 3 75 0 7 0 Ac e t a l d e h y d e 1.0 6 E + 0 0 2 1.2 4 E - 0 1 2 1. 4 1 E - 0 5 2 1.0 0 E + 0 6 3 3. 2 3 E - 0 3 3 7.8 7 E - 0 5 25 29 3 . 1 0 4 46 6 . 0 0 4 6.1 6 E + 0 3 4 2.2 0 E - 0 6 3 9.0 0 E - 0 3 3 0.7 8 3 8 L 9.02E+0 2 4.41E+01 3 75 0 9 2 Me t h y l e n e c h l o r i d e 1.1 7 E + 0 1 1 1.0 1 E - 0 1 1 1. 1 7 E - 0 5 1 1.3 0 E + 0 4 3 8. 9 6 E - 0 2 3 2.1 8 E - 0 3 25 3.1 3 E + 0 2 1 5.1 0 E + 0 2 1 6.7 1 E + 0 3 1 4.7 0 E - 0 7 3 3.0 1 E + 0 0 3 1.3 3 E+ 0 0 4 L 4.33E+02 8.49E+01 3 75 1 5 0 Ca r b o n d i s u l f i d e 4.5 7 E + 0 1 1 1.0 4 E - 0 1 1 1. 0 0 E - 0 5 1 1.1 9 E + 0 3 3 1.2 4 E + 0 0 3 3.0 2 E - 0 2 25 3.1 9 E + 0 2 1 5.5 2 E + 0 2 1 6.3 9 E + 0 3 1 0. 0 0 E + 0 0 3 7.0 0 E - 0 1 3 1.2 6 E + 00 4 L 3.59E+02 7.61E+01 3 75 2 1 8 Eth y l e n e o x i d e 1.3 3 E + 0 0 2 1.0 4 E - 0 1 2 1. 4 5 E - 0 5 2 3.0 4 E + 0 5 3 2. 2 7 E - 0 2 3 5.5 4 E - 0 4 25 28 3 . 6 0 4 46 9 . 0 0 4 6.1 0 E + 0 3 4 1.0 0 E - 0 4 3 0.0 0 E + 0 0 3 0.3 1 4 6 8 L 1.25 E+03 4.41E+01 3 75 2 5 2 Bro m o f o r m 8.7 1 E + 0 1 1 1.4 9 E - 0 2 1 1. 0 3 E - 0 5 1 3.1 0 E + 0 3 3 2. 4 1 E - 0 2 3 5.8 8 E - 0 4 25 4.2 2 E + 0 2 1 6.9 6 E + 0 2 1 9.4 8 E + 0 3 1 1.1 0 E - 0 6 3 7.0 0 E - 0 2 3 2.9 0 E + 0 0 4 L 5.5 1E+00 2.53E+02 3 X 75 2 7 4 Bro m o d i c h l o r o m e t h a n e 5.5 0 E + 0 1 1 2.9 8 E - 0 2 1 1. 0 6 E - 0 5 1 6.7 4 E + 0 3 3 6. 5 4 E - 0 2 3 1.6 0 E - 0 3 25 3.6 3 E + 0 2 1 5.8 6 E + 0 2 1 7.8 0 E + 0 3 1 1.7 7 E - 0 5 3 7.0 0 E - 0 2 3 1 .98 E + 0 0 4 L 5.00E+01 1.64E+02 3 X X 75 2 9 6 2-C h l o r o p r o p a n e 9.1 4 E + 0 0 2 8.8 8 E - 0 2 2 1. 0 1 E - 0 5 2 3.7 3 E + 0 3 3 5. 9 3 E - 0 1 3 1.4 5 E - 0 2 25 30 8 . 7 0 4 48 5 . 0 0 6 6.2 9 E + 0 3 4 0. 0 0 E + 0 0 3 1.0 2 E - 0 1 3 0.8 6 1 7 4 L 5.2 3E+02 7.85E+01 3 75 3 4 3 1,1 - D i c h l o r o e t h a n e 3.1 6 E + 0 1 1 7.4 2 E - 0 2 1 1. 0 5 E - 0 5 1 5.0 6 E + 0 3 3 2. 3 0 E - 0 1 3 5.6 1 E - 0 3 25 3.3 1 E + 0 2 1 5.2 3 E + 0 2 1 6.9 0 E + 0 3 1 0. 0 0 E + 0 0 3 5.0 0 E - 0 1 3 1.1 8 E+ 0 0 4 L 2.27E+02 9.90E+01 3 75 3 5 4 1,1 - D i c h l o r o e t h y l e n e 5.8 9 E + 0 1 1 9.0 0 E - 0 2 1 1. 0 4 E - 0 5 1 2.2 5 E + 0 3 3 1.0 7 E + 0 0 3 2.6 0 E - 0 2 25 3.0 5 E + 0 2 1 5.7 6 E + 0 2 1 6.2 5 E + 0 3 1 0. 0 0 E + 0 0 3 2.0 0 E - 0 1 3 1 .21 E + 0 0 4 L 6.00E+02 9.69E+01 3 75 4 5 6 Ch l o r o d i f l u o r o m e t h a n e 4.7 9 E + 0 1 2 1.0 1 E - 0 1 2 1. 2 8 E - 0 5 2 2.0 0 E + 0 0 3 1.1 0 E + 0 0 3 2.7 0 E - 0 2 25 23 2 . 4 0 4 36 9 . 3 0 4 4.8 4 E + 0 3 6 0. 0 0 E + 0 0 3 5.0 0 E + 0 1 3 1.2 0 9 8 L 7.48E+03 8.65E+01 3 75 6 9 4 Tri c h l o r o f l u o r o m e t h a n e 4.9 7 E + 0 2 2 8.7 0 E - 0 2 2 9. 7 0 E - 0 6 2 1.1 0 E + 0 3 3 3.9 7 E + 0 0 3 9.6 8 E - 0 2 25 29 6 . 7 0 4 47 1 . 0 0 6 6.0 0 E + 0 3 6* 0. 0 0 E + 0 0 3 7.0 0 E - 0 1 3 1.4 87 9 8 L 8.03E+02 1.37E+02 3 75 7 1 8 Dic h l o r o d i f l u o r o m e t h a n e 4.5 7 E + 0 2 2 6.6 5 E - 0 2 2 9. 9 2 E - 0 6 2 2.8 0 E + 0 2 3 1.4 0 E + 0 1 3 3.4 2 E - 0 1 25 24 3 . 2 0 4 38 4 . 9 5 4 9.4 2 E + 0 3 6 0. 0 0 E + 0 0 3 2.0 0 E - 0 1 3 1.3 3 8 L 4.85E+03 1.21E+02 3 76 1 3 1 1,1 , 2 - T r i c h l o r o - 1 , 2 , 2 - t r i f l u o 1.1 1 E + 0 4 2 7.8 0 E - 0 2 2 8. 2 0 E - 0 6 2 1.7 0 E + 0 2 3 1.9 7 E + 0 1 3 4.8 0 E - 0 1 25 32 0 . 7 0 4 48 7 . 3 0 4 6.4 6 E + 0 3 4* 0. 0 0 E + 0 0 3 3.0 1 E + 0 1 3 1.5 6 3 5 8 L 3.32E+02 1.87E+02 3 76 4 4 8 He p t a c h l o r 1.4 1 E + 0 6 1 1.1 2 E - 0 2 1 5. 6 9 E - 0 6 1 1.8 0 E - 0 1 3 6.0 5 E + 0 1 3 1.4 8 E + 0 0 25 6.0 4 E + 0 2 1 8.4 6 E + 0 2 1 1.3 0 E + 0 4 1 1.3 0 E - 0 3 3 1.7 5 E - 0 3 3 N A 4 S 4.00E-04 3.73E+02 3 X 77 4 7 4 He x a c h l o r o c y c l o p e n t a d i e n 2.0 0 E + 0 5 1 1.6 1 E - 0 2 1 7. 2 1 E - 0 6 1 1.8 0 E + 0 0 3 1.1 0 E + 0 0 3 2.6 9 E - 0 2 25 5.1 2 E + 0 2 1 7.4 6 E + 0 2 1 1.0 9 E + 0 4 1 0. 0 0 E + 0 0 3 2.0 0 E - 0 4 3 1.7 0 E + 0 0 4 L 6.00E-02 2.73E+02 3 78 8 3 1 Is o b u t a n o l 2.5 9 E + 0 0 2 8.6 0 E - 0 2 2 9. 3 0 E - 0 6 2 8.5 0 E + 0 4 3 4. 8 3 E - 0 4 3 1.1 8 E - 0 5 25 38 1 . 0 4 4 54 7 . 7 8 4 1.0 9 E + 0 4 6 0. 0 0 E + 0 0 3 1.0 5 E + 0 0 3 0.8 0 1 8 4 L 1.05E+01 7.41E+01 3 X 78 8 7 5 1,2 - D i c h l o r o p r o p a n e 4.3 7 E + 0 1 1 7.8 2 E - 0 2 1 8. 7 3 E - 0 6 1 2.8 0 E + 0 3 3 1. 1 5 E - 0 1 3 2.7 9 E - 0 3 25 3.7 0 E + 0 2 1 5.7 2 E + 0 2 1 7.5 9 E + 0 3 1 1.9 4 E - 0 5 3 4.0 0 E - 0 3 3 1.1 3E + 0 0 4 L 5.20E+01 1.13E+02 3 X 78 9 3 3 Me t h y l e t h y l k e t o n e ( 2 - b u t a 2.3 0 E + 0 0 2 8.0 8 E - 0 2 2 9. 8 0 E - 0 6 2 2.2 3 E + 0 5 3 2.2 9 E - 0 3 3 5.5 8 E - 0 5 25 35 2 . 5 0 4 53 6 . 7 8 4 7.4 8 E + 0 3 4 0. 0 0 E + 0 0 3 1.0 0 E + 0 0 3 0.8 0 5 4 4 L 9.53E+01 7.21E+01 3 79 0 0 5 1,1 , 2 - T r i c h l o r o e t h a n e 5.0 1 E + 0 1 1 7.8 0 E - 0 2 1 8. 8 0 E - 0 6 1 4.4 2 E + 0 3 3 3. 7 3 E - 0 2 3 9.1 1 E - 0 4 25 3.8 6 E + 0 2 1 6.0 2 E + 0 2 1 8.3 2 E + 0 3 1 1.6 0 E - 0 5 3 1.4 0 E - 0 2 3 1 .4 4 E + 0 0 4 L 2.33E+01 1.33E+02 3 X 79 0 1 6 Tri c h l o r o e t h y l e n e 1.6 6 E + 0 2 1 7.9 0 E - 0 2 1 9. 1 0 E - 0 6 1 1.4 7 E + 0 3 3 4. 2 1 E - 0 1 3 1.0 3 E - 0 2 25 3.6 0 E + 0 2 1 5.4 4 E + 0 2 1 7.5 1 E + 0 3 1 1.1 0 E - 0 4 3 4.0 0 E - 0 2 3 1.4 6 E +0 0 4 L 7.35E+01 1.31E+02 3 X 79 2 0 9 Me t h y l a c e t a t e 3.2 6 E + 0 0 2 1.0 4 E - 0 1 2 1. 0 0 E - 0 5 2 2.0 0 E + 0 3 3 4. 8 4 E - 0 3 3 1.1 8 E - 0 4 25 32 9 . 8 0 4 50 6 . 7 0 6 7.2 6 E + 0 3 6 0. 0 0 E + 0 0 3 3.5 0 E + 0 0 3 0.9 3 4 2 4 L 2.35 E+02 7.41E+01 3 X 79 3 4 5 1,1 , 2 , 2 - T e t r a c h l o r o e t h a n e 9.3 3 E + 0 1 1 7.1 0 E - 0 2 1 7. 9 0 E - 0 6 1 2.9 6 E + 0 3 3 1. 4 1 E - 0 2 3 3.4 4 E - 0 4 25 4.2 0 E + 0 2 1 6.6 1 E + 0 2 1 9.0 0 E + 0 3 1 5.8 0 E - 0 5 3 2.1 0 E - 01 3 1.6 0 E + 0 0 4 L 4.62E+00 1.68E+02 3 X 79 4 6 9 2-N i t r o p r o p a n e 1.1 7 E + 0 1 2 9.2 3 E - 0 2 2 1. 0 1 E - 0 5 2 1.7 0 E + 0 4 3 5. 0 3 E - 0 3 3 1.2 3 E - 0 4 25 39 3 . 2 0 4 59 4 . 0 0 8 8.3 8 E + 0 3 8 2.6 9 E - 0 3 3 2.0 0 E - 0 2 3 0.9 8 7 6 8 L 1.80 E+01 8.91E+01 3 80 6 2 6 Me t h y l m e t h a c r y l a t e 6.9 8 E + 0 0 2 7.7 0 E - 0 2 2 8. 6 0 E - 0 6 2 1.5 0 E + 0 4 3 1. 3 8 E - 0 2 3 3.3 6 E - 0 4 25 37 3 . 5 0 4 56 7 . 0 0 6 8.9 7 E + 0 3 6 0. 0 0 E + 0 0 3 7.0 0 E - 0 1 3 0.9 4 4 4 L 3 .84E+01 1.00E+02 3 83 3 2 9 Ac e n a p h t h e n e 7.0 8 E + 0 3 1 4.2 1 E - 0 2 1 7. 6 9 E - 0 6 1 3.5 7 E + 0 0 3 6. 3 4 E - 0 3 3 1.5 5 E - 0 4 25 5.5 1 E + 0 2 1 8.0 3 E + 0 2 1 1.2 2 E + 0 4 1 0. 0 0 E + 0 0 3 2.1 0 E - 0 1 3 N A 4 S 2.50E-03 1.54E+02 3 X 86 7 3 7 Flu o r e n e 1.3 8 E + 0 4 1 3.6 3 E - 0 2 1 7. 8 8 E - 0 6 1 1.9 8 E + 0 0 3 2. 6 0 E - 0 3 3 6.3 4 E - 0 5 25 5.7 0 E + 0 2 1 8.7 0 E + 0 2 1 1.2 7 E + 0 4 1 0. 0 0 E + 0 0 3 1.4 0 E - 0 1 3 N A 4 S 6.33E-04 1.66E+02 3 X 87 6 8 3 He x a c h l o r o - 1 , 3 - b u t a d i e n e 5.3 7 E + 0 4 1 5.6 1 E - 0 2 1 6. 1 6 E - 0 6 1 3.2 0 E + 0 0 3 3. 3 3 E - 0 1 3 8.1 3 E - 0 3 25 4.8 6 E + 0 2 1 7.3 8 E + 0 2 1 1.0 2 E + 0 4 1 2.2 0 E - 0 5 3 7.0 0 E - 0 4 3 1.5 6 E + 0 0 4 L 2.21E-01 2.61E+02 3 X 88 7 2 2 o-N i t r o t o l u e n e 3.2 4 E + 0 2 2 5.8 7 E - 0 2 2 8. 6 7 E - 0 6 2 6.5 0 E + 0 2 3 5. 1 1 E - 0 4 3 1.2 5 E - 0 5 25 49 5 . 0 0 4 72 0 . 0 0 8 1.2 2 E + 0 4 6 0. 0 0 E + 0 0 3 3.5 0 E - 0 2 3 1.1 6 3 8 L 4.50E -02 1.37E+02 3 X 91 2 0 3 Na p h t h a l e n e 2.0 0 E + 0 3 1 5.9 0 E - 0 2 1 7. 5 0 E - 0 6 1 3.1 0 E + 0 1 3 1. 9 8 E - 0 2 3 4.8 2 E - 0 4 25 4.9 1 E + 0 2 1 7.4 8 E + 0 2 1 1.0 4 E + 0 4 1 0. 0 0 E + 0 0 3 3.0 0 E - 0 3 3 N A 4 S 8.50E-0 2 1.28E+02 3 91 5 7 6 2-M e t h y l n a p h t h a l e n e 2.8 1 E + 0 3 2 5.2 2 E - 0 2 2 7. 7 5 E - 0 6 2 2.4 6 E + 0 1 3 2. 1 2 E - 0 2 3 5.1 7 E - 0 4 25 51 4 . 2 6 4 76 1 . 0 0 4 1.2 6 E + 0 4 8 0. 0 0 E + 0 0 3 7.0 0 E - 0 2 3 1.0 0 5 8 4 S 5.50E-02 1.42E+02 3 X 92 5 2 4 Bip h e n y l 4.3 8 E + 0 3 2 4.0 4 E - 0 2 2 8. 1 5 E - 0 6 2 7.4 5 E + 0 0 3 1. 2 3 E - 0 2 3 2.9 9 E - 0 4 25 52 9 . 1 0 4 78 9 . 0 0 4 1.0 9 E + 0 4 8 0. 0 0 E + 0 0 3 1.7 5 E - 0 1 3 1.0 4 4 S 9.64E-03 1.54 E+02 3 X 95 4 7 6 o-X y l e n e 3.6 3 E + 0 2 1 8.7 0 E - 0 2 1 1. 0 0 E - 0 5 1 1.7 8 E + 0 2 3 2. 1 2 E - 0 1 3 5.1 8 E - 0 3 25 4.1 8 E + 0 2 1 6.3 0 E + 0 2 1 8.6 6 E + 0 3 1 0. 0 0 E + 0 0 3 7.0 0 E + 0 0 3 8.8 0 E - 0 1 4 L 6.61 E+00 1.06E+02 3 X 95 5 0 1 1,2 - D i c h l o r o b e n z e n e 6.1 7 E + 0 2 1 6.9 0 E - 0 2 1 7. 9 0 E - 0 6 1 1.5 6 E + 0 2 3 7. 7 7 E - 0 2 3 1.9 0 E - 0 3 25 4.5 4 E + 0 2 1 7.0 5 E + 0 2 1 9.7 0 E + 0 3 1 0. 0 0 E + 0 0 3 2.0 0 E - 0 1 3 1.3 1E + 0 0 4 L 1.36E+00 1.47E+02 3 95 5 7 8 2-C h l o r o p h e n o l 3.8 8 E + 0 2 1 5.0 1 E - 0 2 1 9. 4 6 E - 0 6 1 2.2 0 E + 0 4 3 1. 6 0 E - 0 2 3 3.9 0 E - 0 4 25 4.4 8 E + 0 2 1 6.7 5 E + 0 2 1 9.5 7 E + 0 3 1 0. 0 0 E + 0 0 3 1.7 5 E - 0 2 3 1.2 6 E + 0 0 4 L 2.34E+00 1.29E+02 3 X 95 6 3 6 1,2 , 4 - T r i m e t h y l b e n z e n e 1.3 5 E + 0 3 2 6.0 6 E - 0 2 2 7. 9 2 E - 0 6 2 5.7 0 E + 0 1 3 2. 5 2 E - 0 1 3 6.1 4 E - 0 3 25 44 2 . 3 0 4 64 9 . 1 7 4 9.3 7 E + 0 3 6 0. 0 0 E + 0 0 3 5.9 5 E - 0 3 3 0.8 7 58 4 L 2.10E+00 1.20E+02 3 96 1 8 4 1,2 , 3 - T r i c h l o r o p r o p a n e 2.2 0 E + 0 1 2 7.1 0 E - 0 2 2 7. 9 0 E - 0 6 2 1.7 5 E + 0 3 3 1. 6 7 E - 0 2 3 4.0 8 E - 0 4 25 43 0 . 0 0 4 65 2 . 0 0 6 9.1 7 E + 0 3 8 5.7 1 E - 0 4 3 4.9 0 E - 0 3 3 1.3 8 89 4 L 3.69E+00 1.47E+02 3 X 96 3 3 3 Me t h y l a c r y l a t e 4.5 3 E + 0 0 2 9.7 6 E - 0 2 2 1. 0 2 E - 0 5 2 6.0 0 E + 0 4 3 7. 6 8 E - 0 3 3 1.8 7 E - 0 4 25 35 3 . 7 0 4 53 6 . 0 0 7 7.7 5 E + 0 3 7 0. 0 0 E + 0 0 3 1.0 5 E - 0 1 3 0.9 5 3 5 4 L 8.8 0E+01 8.61E+01 3 X 97 6 3 2 Eth y l m e t h a c r y l a t e 2.9 5 E + 0 1 2 6.5 3 E - 0 2 2 8. 3 7 E - 0 6 2 3.6 7 E + 0 3 3 3. 4 4 E - 0 2 3 8.4 0 E - 0 4 25 39 0 . 0 0 4 57 1 . 0 0 8 1.1 0 E + 0 4 6 0. 0 0 E + 0 0 3 3.1 5 E - 0 1 3 0.9 1 3 5 4 L 2 .06E+01 1.14E+02 3 X 98 0 6 6 te r t - B u t y l b e n z e n e 7.7 1 E + 0 2 2 5.6 5 E - 0 2 2 8. 0 2 E - 0 6 2 2.9 5 E + 0 1 3 4. 8 7 E - 0 1 3 1.1 9 E - 0 2 25 44 2 . 1 0 4 12 2 0 . 0 0 9 8.9 8 E + 0 3 8 0. 0 0 E + 0 0 3 1.4 0 E - 0 1 3 0.8 6 6 5 4 L 2.20E+00 1.34E+02 3 X 98 8 2 8 Cu m e n e 4.8 9 E + 0 2 2 6.5 0 E - 0 2 2 7. 1 0 E - 0 6 2 6.1 3 E + 0 1 3 4.7 4 E + 0 1 3 1.1 6 E + 0 0 25 42 5 . 5 6 4 63 1 . 1 0 4 1.0 3 E + 0 4 6 0. 0 0 E + 0 0 3 4.0 0 E - 0 1 3 0.8 6 1 8 4 L 4.50E+00 1.20 E+02 3 98 8 6 2 Ac e t o p h e n o n e 5.7 7 E + 0 1 2 6.0 0 E - 0 2 2 8. 7 3 E - 0 6 2 6.1 3 E + 0 3 3 4. 3 8 E - 0 4 3 1.0 7 E - 0 5 25 47 5 . 0 0 4 70 9 . 5 0 4 1.1 7 E + 0 4 6 0. 0 0 E + 0 0 3 3.5 0 E - 0 1 3 1.0 2 8 1 4 S,L 3.97 E-01 1.20E+02 3 X 98 9 5 3 Nit r o b e n z e n e 6.4 6 E + 0 1 1 7.6 0 E - 0 2 1 8. 6 0 E - 0 6 1 2.0 9 E + 0 3 3 9. 8 2 E - 0 4 3 2.3 9 E - 0 5 25 4.8 4 E + 0 2 1 7.1 9 E + 0 2 1 1.0 6 E + 0 4 1 0. 0 0 E + 0 0 3 2.0 0 E - 0 3 3 1.2 0 E + 0 0 4 L 2.45E-01 1.23E+02 3 10 0 4 1 4 Eth y l b e n z e n e 3.6 3 E + 0 2 1 7.5 0 E - 0 2 1 7. 8 0 E - 0 6 1 1.6 9 E + 0 2 3 3. 2 2 E - 0 1 3 7.8 6 E - 0 3 25 4.0 9 E + 0 2 1 6.1 7 E + 0 2 1 8.5 0 E + 0 3 1 1.1 0 E - 0 6 3 1.0 0 E + 0 0 3 8.6 7 E - 0 1 4 L 9.60E+00 1.06E+02 3 10 0 4 2 5 Sty r e n e 7.7 6 E + 0 2 1 7.1 0 E - 0 2 1 8. 0 0 E - 0 6 1 3.1 0 E + 0 2 3 1. 1 2 E - 0 1 3 2.7 4 E - 0 3 25 4.1 8 E + 0 2 1 6.3 6 E + 0 2 1 8.7 4 E + 0 3 1 0. 0 0 E + 0 0 3 1.0 0 E + 0 0 3 9.0 6 E - 0 1 4 L 6.12 E+00 1.04E+02 3 10 0 4 4 7 Be n z y l c h l o r i d e 6.1 4 E + 0 1 2 7.5 0 E - 0 2 2 7. 8 0 E - 0 6 2 5.2 5 E + 0 2 3 1. 7 0 E - 0 2 3 4.1 4 E - 0 4 25 45 2 . 0 0 4 68 5 . 0 0 8 8.7 7 E + 0 3 6 4.8 6 E - 0 5 3 0.0 0 E + 0 0 3 1.1 0 0 4 4 L 1.3 1E+00 1.27E+02 3 X 10 0 5 2 7 Be n z a l d e h y d e 4.5 9 E + 0 1 2 7.2 1 E - 0 2 2 9. 0 7 E - 0 6 2 3.3 0 E + 0 3 3 9. 7 3 E - 0 4 3 2.3 7 E - 0 5 25 45 2 . 0 0 4 69 5 . 0 0 4 1.1 7 E + 0 4 6 0. 0 0 E + 0 0 3 3.5 0 E - 0 1 3 1.0 4 1 5 4 L 9.00E -01 1.06E+02 3 X 10 3 6 5 1 n-P r o p y l b e n z e n e 5.6 2 E + 0 2 2 6.0 1 E - 0 2 2 7. 8 3 E - 0 6 2 6.0 0 E + 0 1 3 4. 3 7 E - 0 1 3 1.0 7 E - 0 2 25 43 2 . 2 0 4 63 0 . 0 0 4 9.1 2 E + 0 3 8 0. 0 0 E + 0 0 3 1.4 0 E - 0 1 3 0.8 6 2 4 L 2.5 0E+00 1.20E+02 3 X 10 4 5 1 8 n-B u t y l b e n z e n e 1.1 1 E + 0 3 2 5.7 0 E - 0 2 2 8. 1 2 E - 0 6 2 2.0 0 E + 0 0 3 5. 3 8 E - 0 1 3 1.3 1 E - 0 2 25 45 6 . 4 6 4 66 0 . 5 0 4 9.2 9 E + 0 3 4 0. 0 0 E + 0 0 3 1.4 0 E - 0 1 3 0.8 6 0 1 4 L 1.0 0E+00 1.34E+02 3 X 10 6 4 2 3 p-X y l e n e 3.8 9 E + 0 2 1 7.6 9 E - 0 2 1 8. 4 4 E - 0 6 1 1.8 5 E + 0 2 3 3. 1 3 E - 0 1 3 7.6 4 E - 0 3 25 4.1 2 E + 0 2 1 6.1 6 E + 0 2 1 8.5 3 E + 0 3 1 0. 0 0 E + 0 0 3 7.0 0 E + 0 0 3 8.6 1 E - 0 1 4 L 8.9 0E+00 1.06E+02 3 X 10 6 4 6 7 1,4 - D i c h l o r o b e n z e n e 6.1 7 E + 0 2 1 6.9 0 E - 0 2 1 7. 9 0 E - 0 6 1 7.9 0 E + 0 1 3 9. 8 2 E - 0 2 3 2.3 9 E - 0 3 25 4.4 7 E + 0 2 1 6.8 5 E + 0 2 1 9.2 7 E + 0 3 1 0. 0 0 E + 0 0 3 8.0 0 E - 0 1 3 N A 4 S 1.00E+00 1.47E+02 3 10 6 9 3 4 1,2 - D i b r o m o e t h a n e ( e t h y l e 2.5 0 E + 0 1 2 2.1 7 E - 0 2 2 1. 1 9 E - 0 5 2 4.1 8 E + 0 3 3 3.0 4 E - 0 2 3 7.4 1 E - 0 4 25 40 4 . 6 0 4 58 3 . 0 0 4 8.3 1 E + 0 3 4 2.2 0 E - 0 4 3 2.0 0 E - 0 4 3 2.1 7 9 1 4 L 1.33E+01 1.88E+02 3 10 6 9 9 0 1,3 - B u t a d i e n e 1.9 1 E + 0 1 2 2.4 9 E - 0 1 2 1. 0 8 E - 0 5 2 7.3 5 E + 0 2 3 3.0 1 E + 0 0 3 7.3 4 E - 0 2 25 26 8 . 6 0 4 42 5 . 0 0 4 5.3 7 E + 0 3 4 2.8 0 E - 0 4 3 0.0 0 E + 0 0 3 0. 2 9 3 1 5 8 L 2.1 1E+03 5.41E+01 3 10 7 0 2 8 Ac r o l e i n 2.7 6 E + 0 0 2 1.0 5 E - 0 1 2 1. 2 2 E - 0 5 2 2.1 3 E + 0 5 3 4. 9 9 E - 0 3 3 1.2 2 E - 0 4 25 32 5 . 6 0 4 50 6 . 0 0 8 6.7 3 E + 0 3 6 0. 0 0 E + 0 0 3 2.0 0 E - 0 5 3 0.8 4 4 L 2.74E+02 5.6 1E+01 3 10 7 0 6 2 1,2 - D i c h l o r o e t h a n e 1.7 4 E + 0 1 1 1.0 4 E - 0 1 1 9. 9 0 E - 0 6 1 8.5 2 E + 0 3 3 4. 0 0 E - 0 2 3 9.7 7 E - 0 4 25 3.5 7 E + 0 2 1 5.6 1 E + 0 2 1 7.6 4 E + 0 3 1 2.6 0 E - 0 5 3 0.0 0 E + 0 0 3 1.2 4E + 0 0 4 L 7.89E+01 9.90E+01 3 10 7 1 3 1 Ac r y l o n i t r i l e 5.9 0 E + 0 0 2 1.2 2 E - 0 1 2 1. 3 4 E - 0 5 2 7.4 0 E + 0 4 3 4. 2 1 E - 0 3 3 1.0 3 E - 0 4 25 35 0 . 3 0 4 51 9 . 0 0 6 7.7 9 E + 0 3 8 6.8 0 E - 0 5 3 2.0 0 E - 0 3 3 0.8 0 6 4 L 1.09E +02 5.31E+01 3 10 8 0 5 4 Vin y l a c e t a t e 5.2 5 E + 0 0 1 8.5 0 E - 0 2 1 9. 2 0 E - 0 6 1 2.0 0 E + 0 4 3 2. 0 9 E - 0 2 3 5.1 0 E - 0 4 25 3.4 6 E + 0 2 1 5.1 9 E + 0 2 1 7.8 0 E + 0 3 1 0. 0 0 E + 0 0 3 2.0 0 E - 0 1 3 9.3 2 E - 0 1 4 L 9.02E+01 8.61E+01 3 10 8 1 0 1 Me t h y l i s o b u t y l k e t o n e ( 4 - m 9.0 6 E + 0 0 2 7.5 0 E - 0 2 2 7. 8 0 E - 0 6 2 1.9 0 E + 0 4 3 5.6 4 E - 0 3 3 1.3 8 E - 0 4 25 38 9 . 5 0 4 57 1 . 0 0 4 8.2 4 E + 0 3 4 0. 0 0 E + 0 0 3 8.0 0 E - 0 2 3 0.7 9 7 8 4 L 1.99E+01 1.00E+02 3 10 8 3 8 3 m-X y l e n e 4.0 7 E + 0 2 1 7.0 0 E - 0 2 1 7. 8 0 E - 0 6 1 1.6 1 E + 0 2 3 3. 0 0 E - 0 1 3 7.3 2 E - 0 3 25 4.1 2 E + 0 2 1 6.1 7 E + 0 2 1 8.5 2 E + 0 3 1 0. 0 0 E + 0 0 3 7.0 0 E + 0 0 3 8.6 4 E - 0 1 4 L 8.4 5E+00 1.06E+02 3 X 10 8 6 7 8 1,3 , 5 - T r i m e t h y l b e n z e n e 1.3 5 E + 0 3 2 6.0 2 E - 0 2 2 8. 6 7 E - 0 6 2 2.0 0 E + 0 0 3 2. 4 1 E - 0 1 3 5.8 7 E - 0 3 25 43 7 . 8 9 4 63 7 . 2 5 4 9.3 2 E + 0 3 6 0. 0 0 E + 0 0 3 5.9 5 E - 0 3 3 0.8 65 2 4 L 2.40E+00 1.20E+02 3 10 8 8 7 2 Me t h y l c y c l o h e x a n e 7.8 5 E + 0 1 2 7.3 5 E - 0 2 2 8. 5 2 E - 0 6 2 1.4 0 E + 0 1 3 4.2 2 E + 0 0 3 1.0 3 E - 0 1 25 37 3 . 9 0 4 57 2 . 2 0 4 7.4 7 E + 0 3 4 0. 0 0 E + 0 0 3 3.0 1 E + 0 0 3 0.7 6 9 4 4 L 4.30E+01 9.82E+01 3 10 8 8 8 3 To l u e n e 1.8 2 E + 0 2 1 8.7 0 E - 0 2 1 8. 6 0 E - 0 6 1 5.2 6 E + 0 2 3 2. 7 2 E - 0 1 3 6.6 2 E - 0 3 25 3.8 4 E + 0 2 1 5.9 2 E + 0 2 1 7.9 3 E + 0 3 1 0. 0 0 E + 0 0 3 4.0 0 E - 0 1 3 8.6 7 E - 0 1 4 L 2.84 E+01 9.21E+01 3 10 8 9 0 7 Ch l o r o b e n z e n e 2.1 9 E + 0 2 1 7.3 0 E - 0 2 1 8. 7 0 E - 0 6 1 4.7 2 E + 0 2 3 1. 5 1 E - 0 1 3 3.6 9 E - 0 3 25 4.0 5 E + 0 2 1 6.3 2 E + 0 2 1 8.4 1 E + 0 3 1 0. 0 0 E + 0 0 3 5.9 5 E - 0 2 3 1.1 1 E + 0 0 4 L 1.20E+01 1.13E+02 3 10 9 6 9 3 1-C h l o r o b u t a n e 1.7 2 E + 0 1 2 8.2 6 E - 0 2 2 1. 0 0 E - 0 5 2 1.1 0 E + 0 3 3 6. 9 3 E - 0 1 3 1.6 9 E - 0 2 25 35 1 . 6 0 4 54 2 . 0 0 6 7.2 6 E + 0 3 4 0. 0 0 E + 0 0 3 1.4 0 E + 0 0 3 0.8 8 6 2 4 L 1.0 1E+02 9.26E+01 3 X 11 0 0 0 9 Fu r a n 1.8 6 E + 0 1 2 1.0 4 E - 0 1 2 1. 2 2 E - 0 5 2 1.0 0 E + 0 4 3 2. 2 1 E - 0 1 3 5.3 9 E - 0 3 25 30 4 . 6 0 4 49 0 . 2 0 4 6.4 8 E + 0 3 4 0. 0 0 E + 0 0 3 3.5 0 E - 0 3 3 0.9 5 1 4 4 L 6.00E+02 6.81 E+01 3 X 11 0 5 4 3 He x a n e 4.3 4 E + 0 1 2 2.0 0 E - 0 1 2 7. 7 7 E - 0 6 2 1.2 4 E + 0 1 3 6.8 2 E + 0 1 3 1.6 6 E + 0 0 25 34 1 . 7 0 4 50 8 . 0 0 4 6.9 0 E + 0 3 4 0. 0 0 E + 0 0 3 2.0 0 E - 0 1 3 0.6 5 4 8 4 L 1.51E+02 8.6 2E+01 3 11 1 4 4 4 Bis ( 2 - c h l o r o e t h y l ) e t h e r 1.5 5 E + 0 1 1 6.9 2 E - 0 2 1 7. 5 3 E - 0 6 1 1.7 2 E + 0 4 3 7. 3 6 E - 0 4 3 1.8 0 E - 0 5 25 4.5 1 E + 0 2 1 6.6 0 E + 0 2 1 1.0 8 E + 0 4 1 3.3 0 E - 0 4 3 0.0 0 E + 0 0 3 1.2 2 E + 0 0 4 L 1.55E+00 1.43E+02 3 11 5 2 9 7 En d o s u l f a n 2.1 4 E + 0 3 1 1.1 5 E - 0 2 1 4. 5 5 E - 0 6 1 5.1 0 E - 0 1 3 4. 5 8 E - 0 4 3 1.1 2 E - 0 5 25 6.7 4 E + 0 2 1 9.4 3 E + 0 2 1 1.4 0 E + 0 4 1 0. 0 0 E + 0 0 3 2.1 0 E - 0 2 3 N A 4 S 1.00E-0 5 4.07E+02 3 X 11 8 7 4 1 He x a c h l o r o b e n z e n e 5.5 0 E + 0 4 1 5.4 2 E - 0 2 1 5. 9 1 E - 0 6 1 5.0 0 E - 0 3 3 5. 4 0 E - 0 2 3 1.3 2 E - 0 3 25 5.8 3 E + 0 2 1 8.2 5 E + 0 2 1 1.4 4 E + 0 4 1 4.6 0 E - 0 4 3 2.8 0 E - 0 3 3 N A 4 S 1.80E-05 2.85E+02 3 X 12 0 8 2 1 1,2 , 4 - T r i c h l o r o b e n z e n e 1.7 8 E + 0 3 1 3.0 0 E - 0 2 1 8. 2 3 E - 0 6 1 4.8 8 E + 0 1 3 5. 8 1 E - 0 2 3 1.4 2 E - 0 3 25 4.8 6 E + 0 2 1 7.2 5 E + 0 2 1 1.0 5 E + 0 4 1 0. 0 0 E + 0 0 3 2.0 0 E - 0 1 3 1.4 6 E + 0 0 4 L 4.31E-01 1.81E+02 3 12 3 7 3 9 Cr o t o n a l d e h y d e ( 2 - b u t e n a 4.8 2 E + 0 0 2 9.5 6 E - 0 2 2 1. 0 7 E - 0 5 2 3.6 9 E + 0 4 3 7.9 9 E - 0 4 3 1.9 5 E - 0 5 25 37 5 . 2 0 4 56 8 . 0 0 7 8.6 2 E + 0 0 5 5.4 3 E - 0 4 3 0.0 0 E + 0 0 3 0.8 5 1 6 4 L 7.81E+00 7.01E+01 3 X 12 4 4 8 1 Ch l o r o d i b r o m o m e t h a n e 6.3 1 E + 0 1 1 1.9 6 E - 0 2 1 1. 0 5 E - 0 5 1 2.6 0 E + 0 3 3 3. 2 0 E - 0 2 3 7.8 1 E - 0 4 25 4.1 6 E + 0 2 1 6.7 8 E + 0 2 1 5.9 0 E + 0 3 1 2.4 0 E - 0 5 3 7.0 0 E - 0 2 3 2 .4 5 E + 0 0 4 L 4.90E+00 2.08E+02 3 X X 12 6 9 8 7 Me t h a c r y l o n i t r i l e 3.5 8 E + 0 1 2 1.1 2 E - 0 1 2 1. 3 2 E - 0 5 2 2.5 4 E + 0 4 3 1. 0 1 E - 0 2 3 2.4 6 E - 0 4 25 36 3 . 3 0 4 55 4 . 0 0 8 7.6 0 E + 0 3 6 0. 0 0 E + 0 0 3 7.0 0 E - 0 4 3 0.8 0 0 1 4 L 7.12E+01 6.71E+01 3 12 6 9 9 8 2-C h l o r o - 1 , 3 - b u t a d i e n e ( c 6.7 3 E + 0 1 2 8.5 8 E - 0 2 2 1. 0 3 E - 0 5 2 2.1 2 E + 0 3 3 4.9 1 E - 0 1 3 1.2 0 E - 0 2 25 33 2 . 4 0 4 52 5 . 0 0 8 8.0 7 E + 0 3 7 0. 0 0 E + 0 0 3 7.0 0 E - 0 3 3 0.9 5 6 4 L 2.18E+02 8.85E+01 3 12 7 1 8 4 Te t r a c h l o r o e t h y l e n e 1.5 5 E + 0 2 1 7.2 0 E - 0 2 1 8. 2 0 E - 0 6 1 2.0 0 E + 0 2 3 7. 5 3 E - 0 1 3 1.8 4 E - 0 2 25 3.9 4 E + 0 2 1 6.2 0 E + 0 2 1 8.2 9 E + 0 3 1 3.0 0 E - 0 6 3 0.0 0 E + 0 0 3 1 .62 E + 0 0 4 L 1.86E+01 1.66E+02 3 12 9 0 0 0 Py r e n e 1.0 5 E + 0 5 1 2.7 2 E - 0 2 1 7. 2 4 E - 0 6 1 1.3 5 E + 0 0 3 4. 5 0 E - 0 4 3 1.1 0 E - 0 5 25 6.6 8 E + 0 2 1 9.3 6 E + 0 2 1 1.4 4 E + 0 4 1 0. 0 0 E + 0 0 3 1.0 5 E - 0 1 3 N A 4 S 4.59E-06 2.0 2E+02 3 X 13 2 6 4 9 Dib e n z o f u r a n 5.1 5 E + 0 3 2 2.3 8 E - 0 2 2 6. 0 0 E - 0 6 2 3.1 0 E + 0 0 3 5. 1 5 E - 0 4 3 1.2 6 E - 0 5 25 56 0 . 0 0 4 82 4 . 0 0 6 6.6 4 E + 0 4 6* 0. 0 0 E + 0 0 3 1.4 0 E - 0 2 3 1.1 6 7 9 8 S 1.80 E-04 1.68E+02 3 X B-2 03/14/03 CA S N o . Ch e m i c a l Or g a n i c Ca r b o n Pa r t i t i o n Co e f f i c i e n t He n r y ' s L a w He n r y ' s L a w En t h a l p y o f Co n s t a n t a t Co n s t a n t V ap o r i z a t i o n a t Dif f u s i v i t y i n Dif f u s i v i t y Re f e r e n c e Re f e r e n c e No r m a l Cr i t i c a l th e N o r m a l Un i t R i s k Re f e r e n c e Vapor Ai r in W a t e r Te m p e r a t u r e Te m p e r a t u r e Bo i l i n g P o i n t Te m p e r a t u r e Bo i l i n g P o i n t Fa c t o r Co n c e n t r a t i o n De n s i t y , Pressure Pu r e Co m p o n e n t Wa t e r So l u b i l i t y He n r y ' s La w Co n s t a n t Ph y s i c a l Sta t e a t so i l T e m p Molecular Weight URF extrapolated Rfc extrapolated K oc D a D w S H ' H T R T B T C de l t a H v,b UR F RfC r i VP Mw (c m 3 /g ) (c m 2 /s ) (c m 2 /s ) (m g / L ) (u n i t l e s s ) (a t m - m 3 /m o l ) (o C) (o K) (o K) (c a l / m o l ) (u g / m 3 )-1 (m g / m 3 ) (g / c m 3 ) (S , L , G ) (mm Hg) (g/mole) (X) (X) 13 5 9 8 8 se c - B u t y l b e n z e n e 9.6 6 E + 0 2 2 5.7 0 E - 0 2 2 8. 1 2 E - 0 6 2 3.9 4 E + 0 0 3 5. 6 8 E - 0 1 3 1.3 9 E - 0 2 25 44 6 . 5 0 4 67 9 . 0 0 9 8.8 7 E + 0 4 8 0. 0 0 E + 0 0 3 1.4 0 E - 0 1 3 0.8 6 2 1 8 L 3 .10E-01 1.34E+02 3 X 14 1 7 8 6 Eth y l a c e t a t e 6.4 4 E + 0 0 2 7.3 2 E - 0 2 2 9. 7 0 E - 0 6 2 8.0 3 E + 0 4 3 5. 6 4 E - 0 3 3 1.3 8 E - 0 4 25 35 0 . 2 6 4 52 3 . 3 0 4 7.6 3 E + 0 3 4 0. 0 0 E + 0 0 3 3.1 5 E + 0 0 3 0.9 0 0 3 4 L 9.37E +01 8.81E+01 3 X 15 6 5 9 2 cis - 1 , 2 - D i c h l o r o e t h y l e n e 3.5 5 E + 0 1 1 7.3 6 E - 0 2 1 1. 1 3 E - 0 5 1 3.5 0 E + 0 3 3 1. 6 7 E - 0 1 3 4.0 7 E - 0 3 25 3.3 4 E + 0 2 1 5.4 4 E + 0 2 1 7.1 9 E + 0 3 1 0. 0 0 E + 0 0 3 3.5 0 E - 02 3 1.2 8 E + 0 0 4 L 2.03E+02 9.69E+01 3 X 15 6 6 0 5 tr a n s - 1 , 2 - D i c h l o r o e t h y l e n e 5.2 5 E + 0 1 1 7.0 7 E - 0 2 1 1. 1 9 E - 0 5 1 6.3 0 E + 0 3 3 3.8 4 E - 0 1 3 9.3 6 E - 0 3 25 3.2 1 E + 0 2 1 5.1 7 E + 0 2 1 6.7 2 E + 0 3 1 0. 0 0 E + 0 0 3 7.0 0 E - 0 2 3 1.2 6 E + 0 0 4 L 3.33E+02 9.69E+01 3 X 20 5 9 9 2 Be n z o ( b ) f l u o r a n t h e n e 1.2 3 E + 0 6 1 2.2 6 E - 0 2 1 5. 5 6 E - 0 6 1 1.5 0 E - 0 3 3 4. 5 4 E - 0 3 3 1.1 1 E - 0 4 25 7.1 6 E + 0 2 1 9.6 9 E + 0 2 1 1.7 0 E + 0 4 1 2.0 9 E - 0 4 3 0.0 0 E + 0 0 3 N A 4 S 5.00E-07 2.52E+02 3 X 21 8 0 1 9 Ch r y s e n e 3.9 8 E + 0 5 1 2.4 8 E - 0 2 1 6. 2 1 E - 0 6 1 6.3 0 E - 0 3 3 3. 8 7 E - 0 3 3 9.4 4 E - 0 5 25 7.1 4 E + 0 2 1 9.7 9 E + 0 2 1 1.6 5 E + 0 4 1 2.0 9 E - 0 6 3 0.0 0 E + 0 0 3 N A 4 S 6.23E-09 2 .28E+02 3 X 30 9 0 0 2 Ald r i n 2.4 5 E + 0 6 1 1.3 2 E - 0 2 1 4. 8 6 E - 0 6 1 1.7 0 E - 0 2 3 6. 9 5 E - 0 3 3 1.7 0 E - 0 4 25 6.0 3 E + 0 2 1 8.3 9 E + 0 2 1 1.5 0 E + 0 4 1 4.9 0 E - 0 3 3 1.0 5 E - 0 4 3 N A 4 S 6.00E-06 3.6 5E+02 3 X 31 9 8 4 6 alp h a - H C H ( a l p h a - B H C ) 1.2 3 E + 0 3 1 1.4 2 E - 0 2 1 7. 3 4 E - 0 6 1 2.0 0 E + 0 0 3 4. 3 4 E - 0 4 3 1.0 6 E - 0 5 25 5.9 7 E + 0 2 1 8.3 9 E + 0 2 1 1.5 0 E + 0 4 1 1.8 0 E - 0 3 3 0.0 0 E + 0 0 3 NA 4 S 4.50E-05 2.91E+02 3 54 1 7 3 1 1,3 - D i c h l o r o b e n z e n e 1.9 8 E + 0 3 2 6.9 2 E - 0 2 2 7. 8 6 E - 0 6 2 1.3 4 E + 0 2 3 1. 2 7 E - 0 1 3 3.0 9 E - 0 3 25 44 6 . 0 0 4 68 4 . 0 0 8 9.2 3 E + 0 3 4 0. 0 0 E + 0 0 3 1.0 5 E - 0 1 3 1.2 8 8 4 4 L 2.15E+00 1.47E+02 3 X 54 2 7 5 6 1,3 - D i c h l o r o p r o p e n e 4.5 7 E + 0 1 1 6.2 6 E - 0 2 1 1. 0 0 E - 0 5 1 2.8 0 E + 0 3 3 7. 2 4 E - 0 1 3 1.7 7 E - 0 2 25 3.8 1 E + 0 2 1 5.8 7 E + 0 2 1 7.9 0 E + 0 3 1 4.0 0 E - 0 6 3 2.0 0 E - 0 2 3 1 .22 E + 0 0 4 L 3.40E+01 1.11E+02 3 16 3 4 0 4 4 MT B E 7.2 6 E + 0 0 2 1.0 2 E - 0 1 2 1. 0 5 E - 0 5 2 5.1 0 E + 0 4 3 2. 5 6 E - 0 2 3 6.2 3 E - 0 4 25 32 8 . 3 0 4 49 7 . 1 0 4 6.6 8 E + 0 3 4 0. 0 0 E + 0 0 3 3.0 0 E + 0 0 3 0.7 4 0 5 4 L 2.50E+02 8.82 E+01 3 74 3 9 9 7 6 Me r c u r y ( e l e m e n t a l ) 5.2 0 E + 0 1 1 3.0 7 E - 0 2 1 6. 3 0 E - 0 6 1 2.0 0 E + 0 1 3 4. 4 0 E - 0 1 3 1.0 7 E - 0 2 25 6.3 0 E + 0 2 1 1.7 5 E + 0 3 1 1.4 1 E + 0 4 1 0. 0 0 E + 0 0 3 3.0 0 E - 0 4 3 1 .3 5 E + 0 1 4 L 2.00E-03 2.01E+02 3 So u r c e s : 1 Us e r ' s G u i d e f o r t h e J o h n s o n a n d E t t i n g e r ( 1 9 9 1 ) M o d e l f o r S u b s u r f a c e V a p o r I n t r u s i o n I n t o Bu i l d i n g s ( R e v i s e d ) , D e c e m b e r , 2 0 0 0 2 Wa t e r 9 D a t a b a s e 3 VI D r a f t G u i d a n c e , N o v e m b e r 2 0 0 2 4 CR C H a n d b o o k o f C h e m i s t r y a n d P h y s i c s , 7 6 t h E d i t i o n 5 Th e M e r c k I n d e x , 1 0 t h E d i t i o n 6 Ha z a r d o u s S u b s t a n c e s D a t a B a n k , F e b r u a r y 2 0 0 3 htt p : / / t o x n e t . n l m . n i h . g o v / c g i - b i n / s i s / h t m l g e n ? H S D B 7 We i s s , G . , H a z a r d o u s C h e m i c a l s D a t a B o o k , S e c o n d E d i t i o n . N o y e s D a t a C o r p o r a t i o n . 1 9 8 6 . 8 DE C H E M A W e b D a t b a s e , M a r c h 2 0 0 3 htt p : / / I - s y s t e m s . d e c h e m a . d e / 9 Fle x w a r e E n g i n e e r i n g S o l u t i o n s f o r I n d u s t r y , P r o p e r t i e s o f V a r i o u s G a s e s ww w . f l e x w a r e i n c . c o m / g a s p r o p . h t m * Fo r e n t h a l p y o f v a p o r i z a t i o n , h i g h l i g h t e d v a l u e s a r e e n t h a l p y o f v a p o r i z a t i o n a t v a l u e o t h e r t h a n n o r m a l b o i l i n g p o i n t . Fo r d e n s i t y , h i g h l i g h t e d v a l u e s a r e t a k e n a t t e m p e r a t u r e o t h e r t h a n 2 0 o C. B-3 03/14/03 APPENDIX C EXAMPLE WORKSHEETS FOR THE ADVANCED SOIL CONTAMINATION MODEL C-1 DA T A E N T R Y S H E E T SL - A D V CA L C U L A T E R I S K - B A S E D S O I L C O N C E N T R A T I O N ( e n t e r " X " i n " Y E S " b o x ) Ve r s i o n 3 . 0 ; 0 2 / 0 3 YE S X Re s e t t o O R De f a u l t s CA L C U L A T E I N C R E M E N T A L R I S K S F R O M A C T U A L S O I L C O N C E N T R A T I O N (en t e r " X " i n " Y E S " b o x a n d i n i t i a l s o i l c o n c . b e l o w YE S EN T E R EN T E R In i t i a l Ch e m i c a l so i l CA S N o . co n c . , (n u m b e r s o n l y , C R no d a s h e s ) (µg /k g) Ch e m i c a 71 4 3 2 Be n z e n e MO R E CH E M I C A L P R O P E R T I E S S H E E T He n r y 's He n r y 's En t h a l p y o f Or g an i c Pu r e la w c o n s t a n t la w c o n s t a n t va p o r i z a t i o n a t No r m a l ca r b o n co m p o n e n t Un i t Ph y sical Di f f u s i v i t y Di f f u s i v i t y at r e f e r e n c e re f e r e n c e th e n o r m a l bo i l i n g Cr i t i c a l pa r t i t i o n wa t e r ri s k Re f e r e n c e state at in a i r , in w a t e r , te m p e r a t u r e , te m p e r a t u r e , bo i l i n g p o i n t , po i n t , te m p e r a t u r e , co e f f i c i e n t , so l u b i l i t y , fa c t o r , co n c . , soil D a D w H T R ∆H v,b T B T C K oc S UR F Rf C temperature, (c m 2 /s ) (c m 2 /s ) (a t m - m 3 /m o l ) (o C) (c a l / m o l ) (o K) (o K) (c m 3 /g ) (m g / L ) (µg/ m 3 )-1 (m g / m 3 ) (S,L,G) 8. 8 0 E - 0 2 9. 8 0 E - 0 6 5. 5 4 E - 0 3 25 7 ,34 2 35 3 . 2 4 56 2 . 1 6 5.8 9 E + 0 1 1.7 9 E + 0 3 7. 8 E - 0 6 0. 0 E + 0 0 L EN D 2 o f 8 IN T E R M E D I A T E C A L C U L A T I O N S S H E E T St r a t u m A St r a t u m B Str a t u m C St r a t u m A St r a t u m A St r a t u m A St r a t u m A Flo o r - So u r c e - so i l so i l so i l ef f e c t i v e so i l so i l so i l wa l l In i t i a l s o i l Bldg. Ex p o s u r e bu i l d i n g ai r - f i l l e d ai r - f i l l e d air - f i l l e d to t a l f l u i d in t r i n s i c re l a t i v e a i r ef f e c t i v e v a p o r se a m co n c e n t r a t i o n ventilation du r a t i o n , τ se p a r a t i o n , L T po r o s i t y , θ a A po r o s i t y , θ a B po r o s i t y , θ a C sa t u r a t i o n , S te pe r m e a b i l i t y , k i pe r m e a b i l i t y , k rg pe r m e a b i l i t y , k v pe r i m e t e r , X cra c k us e d , C R rate, Q building (s e c ) (c m ) (c m 3 /c m 3 ) (c m 3 /c m 3 ) (c m 3 /c m 3 ) (c m 3 /c m 3 ) (c m 2 ) (c m 2 ) (c m 2 ) (c m ) (µg/ k g ) (cm 3 /s) 9.4 6 E + 0 8 20 0 0. 2 5 1 0. 2 5 1 0. 3 2 1 0. 2 5 7 1. 8 5 E - 0 9 0. 8 5 4 1. 5 8 E - 0 9 4, 0 0 0 1. 0 0 E + 0 0 2.54E+04 Ar e a o f St r a t u m St r a t u m St r a t u m To t a l en c l o s e d Cr a c k - Cr a c k En t h a l p y o f He n r y ' s l a w He n r y ' s l a w Va p o r A B C ov e r a l l sp a c e to - t o t a l de p t h va p o r i z a t i o n a t co n s t a n t a t co n s t a n t a t vi s c o s i t y a t ef f e c t i v e ef f e c t i v e ef f e c t i v e ef f e c t i v e Diffusion Convection be l o w ar e a be l o w av e . s o i l av e . s o i l av e . s o i l av e . s o i l dif f u s i o n di f f u s i o n di f f u s i o n di f f u s i o n path path gr a d e , A B ra t i o , η gr a d e , Z cra c k te m p e r a t u r e , ∆H v,T S te m p e r a t u r e , H TS te m p e r a t u r e , H'TS te m p e r a t u r e , µTS co e f f i c i e n t , D eff A co e f f i c i e n t , D ef f B co e f f i c i e n t , D ef f C co e f f i c i e n t , D ef f T length, L d length , L p (c m 2 ) (u n i t l e s s ) (c m ) (c a l / m o l ) (a t m - m 3 /m o l ) (u n i t l e s s ) (g / c m - s ) (c m 2 /s ) (c m 2 /s ) (c m 2 /s ) (c m 2 /s ) (cm) (cm) 1.8 0 E + 0 6 2. 2 2 E - 0 4 20 0 8, 1 2 2 2. 6 8 E - 0 3 1. 1 5 E - 0 1 1. 7 5 E - 0 4 5. 5 4 E - 0 3 5.5 4 E - 0 3 1. 4 2 E - 0 2 7.9 7 E - 0 3 200 200 Ex p o n e n t o f In f i n i t e Av e r a g e Cr a c k eq u i v a l e n t so u r c e In f i n i t e Exposure So i l - w a t e r So u r c e va p o r ef f e c t i v e fo u n d a t i o n in d o o r so u r c e Time for duration > pa r t i t i o n va p o r Cr a c k flo w r a t e di f f u s i o n Ar e a o f Pe c l e t at t e n u a t i o n bl d g . Fi n i t e Fi n i t e source time for co e f f i c i e n t , co n c . , ra d i u s , in t o b l d g . , co e f f i c i e n t , cr a c k , nu m b e r , co e f f i c i e n t , co n c . , so u r c e so u r c e depletion, source K d C so u r c e r cra c k Q so i l D cra c k A cr a c k ex p ( P e f ) α C bu i l d i n g β t e r m ψ t e r m τ D depletion (c m 3 /g ) (µg/ m 3 ) (c m ) (c m 3 /s ) (c m 2 /s ) (c m 2 ) (u n i t l e s s ) (u n i t l e s s ) (µg/ m 3 ) (u n i t l e s s ) (s e c ) -1 (sec) (YES/NO) 1. 1 8 E - 0 1 6. 6 8 E + 0 2 0. 1 0 8. 3 3 E + 0 1 5. 5 4 E - 0 3 4. 0 0 E + 0 2 2. 0 6 E + 1 6 3 NA NA 1. 8 6 E + 0 0 8.0 2 E - 0 8 2.94E+07 YES Fi n i t e so u r c e Ma s s Fi n i t e Fi n a l in d o o r lim i t so u r c e fi n i t e Un i t at t e n u a t i o n bld g . bld g . so u r c e b l d g . ri s k Re f e r e n c e co e f f i c i e n t , co n c . , co n c . , co n c . , fa c t o r , co n c . , <α > C bu i l d i n g C bu i l d i n g C bu i l d i n g UR F Rf C (u n i t l e s s ) (µg/ m 3 ) (µg/ m 3 ) (µg/ m 3 ) (µg/ m 3 )-1 (m g / m 3 ) NA 2. 4 9 E - 0 2 NA 2. 4 9 E - 0 2 7. 8 E - 0 6 NA EN D 3 o f 8 RE S U L T S S H E E T RI S K - B A S E D S O I L C O N C E N T R A T I O N C A L C U L A T I O N S : IN C R E M E N T A L R I S K C A L C U L A T I O N S : In c r e m e n t a l Ha z a r d In d o o r ex p o s u r e so i l co n c . , In d o o r ex p o s u r e so i l co n c . , Ri s k - b a s e d in d o o r ex p o s u r e so i l So i l sa t u r a t i o n co n c . , Fi n a l in d o o r ex p o s u r e so i l ris k f r o m va p o r in t r u s i o n t o in d o o r a i r , qu o t i e n t fr o m v a p o r in t r u s i o n t o in d o o r a i r , ca r c i n o g e n no n c a r c i n o g e n co n c . , C sa t co n c . , ca r c i n o g e n no n c a r c i n o g e n (µg /k g) (µg /k g) (µg /k g) (µg /k g) (µg /k g) (u n i t l e s s ) (u n i t l e s s ) 1. 2 6 E + 0 1 N A 1. 2 6 E + 0 1 3. 0 9 E + 0 5 1. 2 6 E + 0 1 N A N A ME S S A G E A N D E R R O R S U M M A R Y B E L O W : (DO N O T U S E R E S U L T S I F E R R O R S A R E P R E S E N T ) ME S S A G E : T h e v a l u e s o f C s o u r c e a n d C b u i l d i n g o n t h e I N T E R C A L C S w o r k s h e e t a r e b a s e d o n u n i t y a n d d o n o t r e p r e s e n t a c t u a l v a l u e s . SC R O L L DO W N TO " E N D " EN D Ap p e n d i x C . x l s 4 o f 8 VL O O K U P T A B L E S So i l P r o p e r t i e s L o o k u p T a b l e Bu l k D e n s i t y SC S S o i l T y p e K s ( c m / h ) α 1 (1 / c m ) N ( u n i t l e s s ) M ( u n i t l e s s ) n ( c m 3 /c m 3 ) θ r ( c m 3 /c m 3 ) Me a n G r a i n D i a m e t e r ( c m ) (g / c m 3 ) θ w (c m 3 /c m 3 ) SC S S o i l N a m e C 0. 6 1 0. 0 1 4 9 6 1. 2 5 3 0.2 0 1 9 0. 4 5 9 0. 0 9 8 0.0 0 9 2 1.4 3 0.2 1 5 Cl a y CL 0. 3 4 0. 0 1 5 8 1 1. 4 1 6 0.2 9 3 8 0. 4 4 2 0. 0 7 9 0.0 1 6 1.4 8 0.1 6 8 Cl a y L o a m L 0. 5 0 0. 0 1 1 1 2 1. 4 7 2 0.3 2 0 7 0. 3 9 9 0. 0 6 1 0.0 2 0 1.5 9 0.1 4 8 Lo a m LS 4. 3 8 0. 0 3 4 7 5 1. 7 4 6 0.4 2 7 3 0. 3 9 0 0. 0 4 9 0.0 4 0 1.6 2 0.0 7 6 Lo a m y S a n d S 26 . 7 8 0. 0 3 5 2 4 3. 1 7 7 0.6 8 5 2 0. 3 7 5 0. 0 5 3 0.0 4 4 1.6 6 0.0 5 4 Sa n d SC 0. 4 7 0. 0 3 3 4 2 1. 2 0 8 0.1 7 2 2 0. 3 8 5 0. 1 1 7 0.0 2 5 1.6 3 0.1 9 7 Sa n d y C l a y SC L 0. 5 5 0. 0 2 1 0 9 1. 3 3 0 0.2 4 8 1 0. 3 8 4 0. 0 6 3 0.0 2 9 1.6 3 0.1 4 6 Sa n d y C l a y L o a m SI 1. 8 2 0. 0 0 6 5 8 1. 6 7 9 0.4 0 4 4 0. 4 8 9 0. 0 5 0 0.0 0 4 6 1.3 5 0.1 6 7 Sil t SI C 0. 4 0 0. 0 1 6 2 2 1. 3 2 1 0.2 4 3 0 0. 4 8 1 0. 1 1 1 0.0 0 3 9 1.3 8 0.2 1 6 Sil t y C l a y SI C L 0. 4 6 0. 0 0 8 3 9 1. 5 2 1 0.3 4 2 5 0. 4 8 2 0. 0 9 0 0.0 0 5 6 1.3 7 0.1 9 8 Sil t y C l a y L o a m SI L 0. 7 6 0. 0 0 5 0 6 1. 6 6 3 0.3 9 8 7 0. 4 3 9 0. 0 6 5 0.0 1 1 1.4 9 0.1 8 0 Sil t L o a m SL 1. 6 0 0. 0 2 6 6 7 1. 4 4 9 0.3 0 9 9 0. 3 8 7 0. 0 3 9 0.0 3 0 1.6 2 0.1 0 3 Sa n d y L o a m Ch e m i c a l P r o p e r t i e s L o o k u p T a b l e Org a n i c Pu r e He n r y ' s He n r y ' s En t h a l p y o f ca r b o n co m p o n e n t la w c o n s t a n t la w c o n s t a n t No r m a l va p o r i z a t i o n a t Un i t Physical pa r t i t i o n Dif f u s i v i t y Dif f u s i v i t y wa t e r He n r y ' s at r e f e r e n c e re f e r e n c e bo i l i n g Cr i t i c a l th e n o r m a l ri s k Re f e r e n c e state at co e f f i c i e n t , in a i r , in w a t e r , so l u b i l i t y , la w c o n s t a n t te m p e r a t u r e , te m p e r a t u r e , po i n t , te m p e r a t u r e , bo i l i n g p o i n t , fa c t o r , conc., soil URF RfC K oc D a D w S H ' H T R T B T C ∆H v,b UR F RfC temperature, extrapolated extrapolated CA S N o . Ch e m i c a l (c m 3 /g ) (c m 2 /s ) (c m 2 /s ) (m g / L ) (u n i t l e s s ) (a t m - m 3 /m o l ) (o C) (o K) (o K) (c a l / m o l ) (µg/m 3 )-1 (m g / m 3 ) (S,L,G) (X) (X) 56 2 3 5 Ca r b o n t e t r a c h l o r i d e 1. 7 4 E + 0 2 7. 8 0 E - 0 2 8.8 0 E - 0 6 7.9 3 E + 0 2 1.2 4 E + 0 0 3. 0 3 E - 0 2 25 34 9 . 9 0 55 6 . 6 0 7,1 2 7 1.5 E - 0 5 0.0E+00 L 57 7 4 9 Ch l o r d a n e 1. 2 0 E + 0 5 1. 1 8 E - 0 2 4.3 7 E - 0 6 5. 6 0 E - 0 2 1. 9 9 E - 0 3 4. 8 5 E - 0 5 25 62 4 . 2 4 88 5 . 7 3 14 , 0 0 0 1.0 E - 0 4 7.0E-04 S 58 8 9 9 ga m m a - H C H ( L i n d a n e ) 1. 0 7 E + 0 3 1. 4 2 E - 0 2 7.3 4 E - 0 6 7.3 0 E + 0 0 5. 7 3 E - 0 4 1. 4 0 E - 0 5 25 59 6 . 5 5 83 9 . 3 6 15 , 0 0 0 3.7 E - 0 4 1.1E-03 S X X 60 2 9 7 Eth y l e t h e r 5. 7 3 E + 0 0 7. 8 2 E - 0 2 8.6 1 E - 0 6 5.6 8 E + 0 4 1.3 5 E + 0 0 3. 2 9 E - 0 2 25 30 7 . 5 0 46 6 . 7 4 6,3 3 8 0. 0 E + 0 0 7.0E-01 L X 60 5 7 1 Die l d r i n 2. 1 4 E + 0 4 1. 2 5 E - 0 2 4.7 4 E - 0 6 1. 9 5 E - 0 1 6. 1 8 E - 0 4 1. 5 1 E - 0 5 25 61 3 . 3 2 84 2 . 2 5 17 , 0 0 0 4.6 E - 0 3 1.8E-04 S X 67 6 4 1 Ac e t o n e 5.7 5 E - 0 1 1. 2 4 E - 0 1 1.1 4 E - 0 5 1.0 0 E + 0 6 1. 5 9 E - 0 3 3. 8 7 E - 0 5 25 32 9 . 2 0 50 8 . 1 0 6,9 5 5 0. 0 E + 0 0 3.5E-01 L X 67 6 6 3 Ch l o r o f o r m 3. 9 8 E + 0 1 1. 0 4 E - 0 1 1.0 0 E - 0 5 7.9 2 E + 0 3 1. 5 0 E - 0 1 3. 6 6 E - 0 3 25 33 4 . 3 2 53 6 . 4 0 6,9 8 8 2.3 E - 0 5 0.0E+00 L 67 7 2 1 He x a c h l o r o e t h a n e 1. 7 8 E + 0 3 2. 5 0 E - 0 3 6.8 0 E - 0 6 5.0 0 E + 0 1 1. 5 9 E - 0 1 3. 8 8 E - 0 3 25 45 8 . 0 0 69 5 . 0 0 9,5 1 0 4.0 E - 0 6 3.5E-03 S X 71 4 3 2 Be n z e n e 5. 8 9 E + 0 1 8. 8 0 E - 0 2 9.8 0 E - 0 6 1.7 9 E + 0 3 2. 2 7 E - 0 1 5. 5 4 E - 0 3 25 35 3 . 2 4 56 2 . 1 6 7,3 4 2 7.8 E - 0 6 0.0E+00 L 71 5 5 6 1, 1 , 1 - T r i c h l o r o e t h a n e 1. 1 0 E + 0 2 7. 8 0 E - 0 2 8.8 0 E - 0 6 1.3 3 E + 0 3 7. 0 3 E - 0 1 1. 7 2 E - 0 2 25 34 7 . 2 4 54 5 . 0 0 7,1 3 6 0. 0 E + 0 0 2.2E+00 L 72 4 3 5 Me t h o x y c h l o r 9. 7 7 E + 0 4 1. 5 6 E - 0 2 4.4 6 E - 0 6 1. 0 0 E - 0 1 6. 4 6 E - 0 4 1. 5 8 E - 0 5 25 65 1 . 0 2 84 8 . 4 9 16 , 0 0 0 0. 0 E + 0 0 1.8E-02 S X 72 5 5 9 DD E 4. 4 7 E + 0 6 1. 4 4 E - 0 2 5.8 7 E - 0 6 1. 2 0 E - 0 1 8. 5 9 E - 0 4 2. 0 9 E - 0 5 25 63 6 . 4 4 86 0 . 3 8 15 , 0 0 0 9.7 E - 0 5 0.0E+00 S X 74 8 3 9 Me t h y l b r o m i d e 1. 0 5 E + 0 1 7. 2 8 E - 0 2 1.2 1 E - 0 5 1.5 2 E + 0 4 2. 5 5 E - 0 1 6. 2 2 E - 0 3 25 27 6 . 7 1 46 7 . 0 0 5,7 1 4 0. 0 E + 0 0 5.0E-03 G 74 8 7 3 Me t h y l c h l o r i d e ( c h l o r o m e t h a n e ) 2. 1 2 E + 0 0 1. 2 6 E - 0 1 6.5 0 E - 0 6 5.3 3 E + 0 3 3. 6 1 E - 0 1 8. 8 0 E - 0 3 25 24 9 . 0 0 41 6 . 2 5 5,1 1 5 1.0 E - 0 6 9.0E-02 L 74 9 0 8 Hy d r o g e n c y a n i d e 3. 8 0 E + 0 0 1. 9 3 E - 0 1 2.1 0 E - 0 5 1.0 0 E + 0 6 5. 4 4 E - 0 3 1. 3 3 E - 0 4 25 29 9 . 0 0 45 6 . 7 0 6,6 7 6 0. 0 E + 0 0 3.0E-03 L 74 9 5 3 Me t h y l e n e bro m i d e 1. 2 6 E + 0 1 4. 3 0 E - 0 2 8.4 4 E - 0 6 1.1 9 E + 0 4 3. 5 2 E - 0 2 8. 5 9 E - 0 4 25 37 0 . 0 0 58 3 . 0 0 7,8 6 8 0. 0 E + 0 0 3.5E-02 L X 75 0 0 3 Ch l o r o e t h a n e ( e t h y l c h l o r i d e ) 4. 4 0 E + 0 0 2. 7 1 E - 0 1 1.1 5 E - 0 5 5.6 8 E + 0 3 3. 6 1 E - 0 1 8. 8 0 E - 0 3 25 28 5 . 3 0 46 0 . 4 0 5,8 7 9 8.3 E - 0 7 1.0E+01 L X 75 0 1 4 Vin y l c h l o r i d e ( c h l o r o e t h e n e ) 1. 8 6 E + 0 1 1. 0 6 E - 0 1 1.2 3 E - 0 5 8.8 0 E + 0 3 1.1 0 E + 0 0 2. 6 9 E - 0 2 25 25 9 . 2 5 43 2 . 0 0 5,2 5 0 8.8 E - 0 6 1.0E-01 G 75 0 5 8 Ac e t o n i t r i l e 4. 2 0 E + 0 0 1. 2 8 E - 0 1 1.6 6 E - 0 5 1.0 0 E + 0 6 1. 4 2 E - 0 3 3. 4 5 E - 0 5 25 35 4 . 6 0 54 5 . 5 0 7,1 1 0 0. 0 E + 0 0 6.0E-02 L 75 0 7 0 Ac e t a l d e h y d e 1. 0 6 E + 0 0 1. 2 4 E - 0 1 1.4 1 E - 0 5 1.0 0 E + 0 6 3. 2 3 E - 0 3 7. 8 7 E - 0 5 25 29 3 . 1 0 46 6 . 0 0 6,1 5 7 2.2 E - 0 6 9.0E-03 L 75 0 9 2 Me t h y l e n e c h l o r i d e 1. 1 7 E + 0 1 1. 0 1 E - 0 1 1.1 7 E - 0 5 1.3 0 E + 0 4 8. 9 6 E - 0 2 2. 1 8 E - 0 3 25 31 3 . 0 0 51 0 . 0 0 6,7 0 6 4.7 E - 0 7 3.0E+00 L 75 1 5 0 Ca r b o n d i s u l f i d e 4. 5 7 E + 0 1 1. 0 4 E - 0 1 1.0 0 E - 0 5 1.1 9 E + 0 3 1.2 4 E + 0 0 3. 0 2 E - 0 2 25 31 9 . 0 0 55 2 . 0 0 6,3 9 1 0. 0 E + 0 0 7.0E-01 L 75 2 1 8 Eth y l e n e o x i d e 1. 3 3 E + 0 0 1. 0 4 E - 0 1 1.4 5 E - 0 5 3.0 4 E + 0 5 2. 2 7 E - 0 2 5. 5 4 E - 0 4 25 28 3 . 6 0 46 9 . 0 0 6,1 0 4 1.0 E - 0 4 0.0E+00 L 75 2 5 2 Br o m o f o r m 8. 7 1 E + 0 1 1. 4 9 E - 0 2 1.0 3 E - 0 5 3.1 0 E + 0 3 2. 4 1 E - 0 2 5. 8 8 E - 0 4 25 42 2 . 3 5 69 6 . 0 0 9,4 7 9 1.1 E - 0 6 7.0E-02 L X 75 2 7 4 Br o m o d i c h l o r o m e t h a n e 5. 5 0 E + 0 1 2. 9 8 E - 0 2 1.0 6 E - 0 5 6.7 4 E + 0 3 6. 5 4 E - 0 2 1. 6 0 E - 0 3 25 36 3 . 1 5 58 5 . 8 5 7,8 0 0 1.8 E - 0 5 7.0E-02 L X X 75 2 9 6 2- C h l o r o p r o p a n e 9. 1 4 E + 0 0 8. 8 8 E - 0 2 1.0 1 E - 0 5 3.7 3 E + 0 3 5. 9 3 E - 0 1 1. 4 5 E - 0 2 25 30 8 . 7 0 48 5 . 0 0 6,2 8 6 0. 0 E + 0 0 1.0E-01 L 75 3 4 3 1, 1 - D i c h l o r o e t h a n e 3. 1 6 E + 0 1 7. 4 2 E - 0 2 1.0 5 E - 0 5 5.0 6 E + 0 3 2. 3 0 E - 0 1 5. 6 1 E - 0 3 25 33 0 . 5 5 52 3 . 0 0 6,8 9 5 0. 0 E + 0 0 5.0E-01 L 75 3 5 4 1, 1 - D i c h l o r o e t h y l e n e 5. 8 9 E + 0 1 9. 0 0 E - 0 2 1.0 4 E - 0 5 2.2 5 E + 0 3 1.0 7 E + 0 0 2. 6 0 E - 0 2 25 30 4 . 7 5 57 6 . 0 5 6,2 4 7 0. 0 E + 0 0 2.0E-01 L 75 4 5 6 Ch l o r o d i f l u o r o m e t h a n e 4. 7 9 E + 0 1 1. 0 1 E - 0 1 1.2 8 E - 0 5 2.0 0 E + 0 0 1.1 0 E + 0 0 2. 7 0 E - 0 2 25 23 2 . 4 0 36 9 . 3 0 4,8 3 6 0. 0 E + 0 0 5.0E+01 L 75 6 9 4 Tri c h l o r o f l u o r o m e t h a n e 4. 9 7 E + 0 2 8. 7 0 E - 0 2 9.7 0 E - 0 6 1.1 0 E + 0 3 3.9 7 E + 0 0 9. 6 8 E - 0 2 25 29 6 . 7 0 47 1 . 0 0 5,9 9 9 0. 0 E + 0 0 7.0E-01 L 75 7 1 8 Dic h l o r o d i f l u o r o m e t h a n e 4. 5 7 E + 0 2 6. 6 5 E - 0 2 9.9 2 E - 0 6 2.8 0 E + 0 2 1.4 0 E + 0 1 3. 4 2 E - 0 1 25 24 3 . 2 0 38 4 . 9 5 9,4 2 1 0. 0 E + 0 0 2.0E-01 L 76 1 3 1 1, 1 , 2 - T r i c h l o r o - 1 , 2 , 2 - t r i f l u o r o e t h a 1. 1 1 E + 0 4 7. 8 0 E - 0 2 8.2 0 E - 0 6 1.7 0 E + 0 2 1.9 7 E + 0 1 4. 8 0 E - 0 1 25 32 0 . 7 0 48 7 . 3 0 6,4 6 3 0. 0 E + 0 0 3.0E+01 L 76 4 4 8 He p t a c h l o r 1. 4 1 E + 0 6 1. 1 2 E - 0 2 5.6 9 E - 0 6 1. 8 0 E - 0 1 6.0 5 E + 0 1 1.4 8 E + 0 0 25 60 3 . 6 9 84 6 . 3 1 13 , 0 0 0 1.3 E - 0 3 1.8E-03 S X 77 4 7 4 He x a c h l o r o c y c l o p e n t a d i e n e 2. 0 0 E + 0 5 1. 6 1 E - 0 2 7.2 1 E - 0 6 1.8 0 E + 0 0 1.1 0 E + 0 0 2. 6 9 E - 0 2 25 51 2 . 1 5 74 6 . 0 0 10 , 9 3 1 0. 0 E + 0 0 2.0E-04 L 78 8 3 1 Is o b u t a n o l 2. 5 9 E + 0 0 8. 6 0 E - 0 2 9.3 0 E - 0 6 8.5 0 E + 0 4 4. 8 3 E - 0 4 1. 1 8 E - 0 5 25 38 1 . 0 4 54 7 . 7 8 10 , 9 3 6 0. 0 E + 0 0 1.1E+00 L X 78 8 7 5 1, 2 - D i c h l o r o p r o p a n e 4. 3 7 E + 0 1 7. 8 2 E - 0 2 8.7 3 E - 0 6 2.8 0 E + 0 3 1. 1 5 E - 0 1 2. 7 9 E - 0 3 25 36 9 . 5 2 57 2 . 0 0 7,5 9 0 1.9 E - 0 5 4.0E-03 L X 78 9 3 3 Me t h y l e t h y l k e t o n e ( 2 - b u t a n o n e ) 2. 3 0 E + 0 0 8. 0 8 E - 0 2 9.8 0 E - 0 6 2.2 3 E + 0 5 2. 2 9 E - 0 3 5. 5 8 E - 0 5 25 35 2 . 5 0 53 6 . 7 8 7,4 8 1 0. 0 E + 0 0 1.0E+00 L 79 0 0 5 1, 1 , 2 - T r i c h l o r o e t h a n e 5. 0 1 E + 0 1 7. 8 0 E - 0 2 8.8 0 E - 0 6 4.4 2 E + 0 3 3. 7 3 E - 0 2 9. 1 1 E - 0 4 25 38 6 . 1 5 60 2 . 0 0 8,3 2 2 1.6 E - 0 5 1.4E-02 L X 79 0 1 6 Tri c h l o r o e t h y l e n e 1. 6 6 E + 0 2 7. 9 0 E - 0 2 9.1 0 E - 0 6 1.4 7 E + 0 3 4. 2 1 E - 0 1 1. 0 3 E - 0 2 25 36 0 . 3 6 54 4 . 2 0 7,5 0 5 1.1 E - 0 4 4.0E-02 L X 79 2 0 9 Me t h y l a c e t a t e 3. 2 6 E + 0 0 1. 0 4 E - 0 1 1.0 0 E - 0 5 2.0 0 E + 0 3 4. 8 4 E - 0 3 1. 1 8 E - 0 4 25 32 9 . 8 0 50 6 . 7 0 7,2 6 0 0. 0 E + 0 0 3.5E+00 L X 79 3 4 5 1, 1 , 2 , 2 - T e t r a c h l o r o e t h a n e 9. 3 3 E + 0 1 7. 1 0 E - 0 2 7.9 0 E - 0 6 2.9 6 E + 0 3 1. 4 1 E - 0 2 3. 4 4 E - 0 4 25 41 9 . 6 0 66 1 . 1 5 8,9 9 6 5.8 E - 0 5 2.1E-01 L X 79 4 6 9 2- N i t r o p r o p a n e 1. 1 7 E + 0 1 9. 2 3 E - 0 2 1.0 1 E - 0 5 1.7 0 E + 0 4 5. 0 3 E - 0 3 1. 2 3 E - 0 4 25 39 3 . 2 0 59 4 . 0 0 8,3 8 3 2.7 E - 0 3 2.0E-02 L 80 6 2 6 Me t h y l m e t h a c r y l a t e 6. 9 8 E + 0 0 7. 7 0 E - 0 2 8.6 0 E - 0 6 1.5 0 E + 0 4 1. 3 8 E - 0 2 3. 3 6 E - 0 4 25 37 3 . 5 0 56 7 . 0 0 8,9 7 5 0. 0 E + 0 0 7.0E-01 L 83 3 2 9 Ac e n a p h t h e n e 7. 0 8 E + 0 3 4. 2 1 E - 0 2 7.6 9 E - 0 6 3.5 7 E + 0 0 6. 3 4 E - 0 3 1. 5 5 E - 0 4 25 55 0 . 5 4 80 3 . 1 5 12 , 1 5 5 0. 0 E + 0 0 2.1E-01 S X 86 7 3 7 Flu o r e n e 1. 3 8 E + 0 4 3. 6 3 E - 0 2 7.8 8 E - 0 6 1.9 8 E + 0 0 2. 6 0 E - 0 3 6. 3 4 E - 0 5 25 57 0 . 4 4 87 0 . 0 0 12 , 6 6 6 0. 0 E + 0 0 1.4E-01 S X 87 6 8 3 He x a c h l o r o - 1 , 3 - b u t a d i e n e 5. 3 7 E + 0 4 5. 6 1 E - 0 2 6.1 6 E - 0 6 3.2 0 E + 0 0 3. 3 3 E - 0 1 8. 1 3 E - 0 3 25 48 6 . 1 5 73 8 . 0 0 10 , 2 0 6 2.2 E - 0 5 7.0E-04 L X 88 7 2 2 o- N i t r o t o l u e n e 3. 2 4 E + 0 2 5. 8 7 E - 0 2 8.6 7 E - 0 6 6.5 0 E + 0 2 5. 1 1 E - 0 4 1. 2 5 E - 0 5 25 49 5 . 0 0 72 0 . 0 0 12 , 2 3 9 0. 0 E + 0 0 3.5E-02 L X 91 2 0 3 Na p h t h a l e n e 2. 0 0 E + 0 3 5. 9 0 E - 0 2 7.5 0 E - 0 6 3.1 0 E + 0 1 1. 9 8 E - 0 2 4. 8 2 E - 0 4 25 49 1 . 1 4 74 8 . 4 0 10 , 3 7 3 0. 0 E + 0 0 3.0E-03 S 91 5 7 6 2- M e t h y l n a p h t h a l e n e 2. 8 1 E + 0 3 5. 2 2 E - 0 2 7.7 5 E - 0 6 2.4 6 E + 0 1 2. 1 2 E - 0 2 5. 1 7 E - 0 4 25 51 4 . 2 6 76 1 . 0 0 12 , 6 0 0 0. 0 E + 0 0 7.0E-02 S X 92 5 2 4 Bip h e n y l 4. 3 8 E + 0 3 4. 0 4 E - 0 2 8.1 5 E - 0 6 7.4 5 E + 0 0 1. 2 3 E - 0 2 2. 9 9 E - 0 4 25 52 9 . 1 0 78 9 . 0 0 10 , 8 9 0 0. 0 E + 0 0 1.8E-01 S X 95 4 7 6 o- X y l e n e 3. 6 3 E + 0 2 8. 7 0 E - 0 2 1.0 0 E - 0 5 1.7 8 E + 0 2 2. 1 2 E - 0 1 5. 1 8 E - 0 3 25 41 7 . 6 0 63 0 . 3 0 8,6 6 1 0. 0 E + 0 0 7.0E+00 L X 95 5 0 1 1, 2 - D i c h l o r o b e n z e n e 6. 1 7 E + 0 2 6. 9 0 E - 0 2 7.9 0 E - 0 6 1.5 6 E + 0 2 7. 7 7 E - 0 2 1. 9 0 E - 0 3 25 45 3 . 5 7 70 5 . 0 0 9,7 0 0 0. 0 E + 0 0 2.0E-01 L 95 5 7 8 2- C h l o r o p h e n o l 3. 8 8 E + 0 2 5. 0 1 E - 0 2 9.4 6 E - 0 6 2.2 0 E + 0 4 1. 6 0 E - 0 2 3. 9 0 E - 0 4 25 44 7 . 5 3 67 5 . 0 0 9,5 7 2 0. 0 E + 0 0 1.8E-02 L X 5 o f 8 VL O O K U P T A B L E S 95 6 3 6 1, 2 , 4 - T r i m e t h y l b e n z e n e 1. 3 5 E + 0 3 6. 0 6 E - 0 2 7.9 2 E - 0 6 5.7 0 E + 0 1 2. 5 2 E - 0 1 6. 1 4 E - 0 3 25 44 2 . 3 0 64 9 . 1 7 9,3 6 9 0. 0 E + 0 0 6.0E-03 L 96 1 8 4 1, 2 , 3 - T r i c h l o r o p r o p a n e 2. 2 0 E + 0 1 7. 1 0 E - 0 2 7.9 0 E - 0 6 1.7 5 E + 0 3 1. 6 7 E - 0 2 4. 0 8 E - 0 4 25 43 0 . 0 0 65 2 . 0 0 9,1 7 1 5.7 E - 0 4 4.9E-03 L X 96 3 3 3 Me t h y l a c r y l a t e 4. 5 3 E + 0 0 9. 7 6 E - 0 2 1.0 2 E - 0 5 6.0 0 E + 0 4 7. 6 8 E - 0 3 1. 8 7 E - 0 4 25 35 3 . 7 0 53 6 . 0 0 7,7 4 9 0. 0 E + 0 0 1.1E-01 L X 97 6 3 2 Eth y l m e t h a c r y l a t e 2. 9 5 E + 0 1 6. 5 3 E - 0 2 8.3 7 E - 0 6 3.6 7 E + 0 3 3. 4 4 E - 0 2 8. 4 0 E - 0 4 25 39 0 . 0 0 57 1 . 0 0 10 , 9 5 7 0. 0 E + 0 0 3.2E-01 L X 98 0 6 6 te r t - B u t y l b e n z e n e 7. 7 1 E + 0 2 5. 6 5 E - 0 2 8.0 2 E - 0 6 2.9 5 E + 0 1 4. 8 7 E - 0 1 1. 1 9 E - 0 2 25 44 2 . 1 0 12 2 0 . 0 0 8,9 8 0 0. 0 E + 0 0 1.4E-01 L X 98 8 2 8 Cu m e n e 4. 8 9 E + 0 2 6. 5 0 E - 0 2 7.1 0 E - 0 6 6.1 3 E + 0 1 4.7 4 E + 0 1 1.1 6 E + 0 0 25 42 5 . 5 6 63 1 . 1 0 10 , 3 3 5 0. 0 E + 0 0 4.0E-01 L 98 8 6 2 Ac e t o p h e n o n e 5. 7 7 E + 0 1 6. 0 0 E - 0 2 8.7 3 E - 0 6 6.1 3 E + 0 3 4. 3 8 E - 0 4 1. 0 7 E - 0 5 25 47 5 . 0 0 70 9 . 5 0 11 , 7 3 2 0. 0 E + 0 0 3.5E-01 S,L X 98 9 5 3 Nit r o b e n z e n e 6. 4 6 E + 0 1 7. 6 0 E - 0 2 8.6 0 E - 0 6 2.0 9 E + 0 3 9. 8 2 E - 0 4 2. 3 9 E - 0 5 25 48 3 . 9 5 71 9 . 0 0 10 , 5 6 6 0. 0 E + 0 0 2.0E-03 L 10 0 4 1 4 Eth y l b e n z e n e 3. 6 3 E + 0 2 7. 5 0 E - 0 2 7.8 0 E - 0 6 1.6 9 E + 0 2 3. 2 2 E - 0 1 7. 8 6 E - 0 3 25 40 9 . 3 4 61 7 . 2 0 8,5 0 1 1.1 E - 0 6 1.0E+00 L 10 0 4 2 5 Sty r e n e 7. 7 6 E + 0 2 7. 1 0 E - 0 2 8.0 0 E - 0 6 3.1 0 E + 0 2 1. 1 2 E - 0 1 2. 7 4 E - 0 3 25 41 8 . 3 1 63 6 . 0 0 8,7 3 7 0. 0 E + 0 0 1.0E+00 L 10 0 4 4 7 Be n z y l c h l o r i d e 6. 1 4 E + 0 1 7. 5 0 E - 0 2 7.8 0 E - 0 6 5.2 5 E + 0 2 1. 7 0 E - 0 2 4. 1 4 E - 0 4 25 45 2 . 0 0 68 5 . 0 0 8,7 7 3 4.9 E - 0 5 0.0E+00 L X 10 0 5 2 7 Be n z a l d e h y d e 4. 5 9 E + 0 1 7. 2 1 E - 0 2 9.0 7 E - 0 6 3.3 0 E + 0 3 9. 7 3 E - 0 4 2. 3 7 E - 0 5 25 45 2 . 0 0 69 5 . 0 0 11 , 6 5 8 0. 0 E + 0 0 3.5E-01 L X 10 3 6 5 1 n- P r o p y l b e n z e n e 5. 6 2 E + 0 2 6. 0 1 E - 0 2 7.8 3 E - 0 6 6.0 0 E + 0 1 4. 3 7 E - 0 1 1. 0 7 E - 0 2 25 43 2 . 2 0 63 0 . 0 0 9,1 2 3 0. 0 E + 0 0 1.4E-01 L X 10 4 5 1 8 n- B u t y l b e n z e n e 1. 1 1 E + 0 3 5. 7 0 E - 0 2 8.1 2 E - 0 6 2.0 0 E + 0 0 5. 3 8 E - 0 1 1. 3 1 E - 0 2 25 45 6 . 4 6 66 0 . 5 0 9,2 9 0 0. 0 E + 0 0 1.4E-01 L X 10 6 4 2 3 p- X y l e n e 3. 8 9 E + 0 2 7. 6 9 E - 0 2 8.4 4 E - 0 6 1.8 5 E + 0 2 3. 1 3 E - 0 1 7. 6 4 E - 0 3 25 41 1 . 5 2 61 6 . 2 0 8,5 2 5 0. 0 E + 0 0 7.0E+00 L X 10 6 4 6 7 1, 4 - D i c h l o r o b e n z e n e 6. 1 7 E + 0 2 6. 9 0 E - 0 2 7.9 0 E - 0 6 7.9 0 E + 0 1 9. 8 2 E - 0 2 2. 3 9 E - 0 3 25 44 7 . 2 1 68 4 . 7 5 9,2 7 1 0. 0 E + 0 0 8.0E-01 S 10 6 9 3 4 1, 2 - D i b r o m o e t h a n e ( e t h y l e n e d i b 2. 5 0 E + 0 1 2. 1 7 E - 0 2 1.1 9 E - 0 5 4.1 8 E + 0 3 3. 0 4 E - 0 2 7. 4 1 E - 0 4 25 40 4 . 6 0 58 3 . 0 0 8,3 1 0 2.2 E - 0 4 2.0E-04 L 10 6 9 9 0 1, 3 - B u t a d i e n e 1. 9 1 E + 0 1 2. 4 9 E - 0 1 1.0 8 E - 0 5 7.3 5 E + 0 2 3.0 1 E + 0 0 7. 3 4 E - 0 2 25 26 8 . 6 0 42 5 . 0 0 5,3 7 0 2.8 E - 0 4 0.0E+00 L 10 7 0 2 8 Ac r o l e i n 2. 7 6 E + 0 0 1. 0 5 E - 0 1 1.2 2 E - 0 5 2.1 3 E + 0 5 4. 9 9 E - 0 3 1. 2 2 E - 0 4 25 32 5 . 6 0 50 6 . 0 0 6,7 3 1 0. 0 E + 0 0 2.0E-05 L 10 7 0 6 2 1, 2 - D i c h l o r o e t h a n e 1. 7 4 E + 0 1 1. 0 4 E - 0 1 9.9 0 E - 0 6 8.5 2 E + 0 3 4. 0 0 E - 0 2 9. 7 7 E - 0 4 25 35 6 . 6 5 56 1 . 0 0 7,6 4 3 2.6 E - 0 5 0.0E+00 L 10 7 1 3 1 Ac r y l o n i t r i l e 5. 9 0 E + 0 0 1. 2 2 E - 0 1 1.3 4 E - 0 5 7.4 0 E + 0 4 4. 2 1 E - 0 3 1. 0 3 E - 0 4 25 35 0 . 3 0 51 9 . 0 0 7,7 8 6 6.8 E - 0 5 2.0E-03 L 10 8 0 5 4 Vin y l a c e t a t e 5. 2 5 E + 0 0 8. 5 0 E - 0 2 9.2 0 E - 0 6 2.0 0 E + 0 4 2. 0 9 E - 0 2 5. 1 0 E - 0 4 25 34 5 . 6 5 51 9 . 1 3 7,8 0 0 0. 0 E + 0 0 2.0E-01 L 10 8 1 0 1 Me t h y l i s o b u t y l k e t o n e ( 4 - m e t h y l - 2 9. 0 6 E + 0 0 7. 5 0 E - 0 2 7.8 0 E - 0 6 1.9 0 E + 0 4 5. 6 4 E - 0 3 1. 3 8 E - 0 4 25 38 9 . 5 0 57 1 . 0 0 8,2 4 3 0. 0 E + 0 0 8.0E-02 L 10 8 3 8 3 m- X y l e n e 4. 0 7 E + 0 2 7. 0 0 E - 0 2 7.8 0 E - 0 6 1.6 1 E + 0 2 3. 0 0 E - 0 1 7. 3 2 E - 0 3 25 41 2 . 2 7 61 7 . 0 5 8,5 2 3 0. 0 E + 0 0 7.0E+00 L X 10 8 6 7 8 1, 3 , 5 - T r i m e t h y l b e n z e n e 1. 3 5 E + 0 3 6. 0 2 E - 0 2 8.6 7 E - 0 6 2.0 0 E + 0 0 2. 4 1 E - 0 1 5. 8 7 E - 0 3 25 43 7 . 8 9 63 7 . 2 5 9,3 2 1 0. 0 E + 0 0 6.0E-03 L 10 8 8 7 2 Me t h y l c y c l o h e x a n e 7. 8 5 E + 0 1 7. 3 5 E - 0 2 8.5 2 E - 0 6 1.4 0 E + 0 1 4.2 2 E + 0 0 1. 0 3 E - 0 1 25 37 3 . 9 0 57 2 . 2 0 7,4 7 4 0. 0 E + 0 0 3.0E+00 L 10 8 8 8 3 To l u e n e 1. 8 2 E + 0 2 8. 7 0 E - 0 2 8.6 0 E - 0 6 5.2 6 E + 0 2 2. 7 2 E - 0 1 6. 6 2 E - 0 3 25 38 3 . 7 8 59 1 . 7 9 7,9 3 0 0. 0 E + 0 0 4.0E-01 L 10 8 9 0 7 Ch l o r o b e n z e n e 2. 1 9 E + 0 2 7. 3 0 E - 0 2 8.7 0 E - 0 6 4.7 2 E + 0 2 1. 5 1 E - 0 1 3. 6 9 E - 0 3 25 40 4 . 8 7 63 2 . 4 0 8,4 1 0 0. 0 E + 0 0 6.0E-02 L 10 9 6 9 3 1- C h l o r o b u t a n e 1. 7 2 E + 0 1 8. 2 6 E - 0 2 1.0 0 E - 0 5 1.1 0 E + 0 3 6. 9 3 E - 0 1 1. 6 9 E - 0 2 25 35 1 . 6 0 54 2 . 0 0 7,2 6 3 0. 0 E + 0 0 1.4E+00 L X 11 0 0 0 9 Fu r a n 1. 8 6 E + 0 1 1. 0 4 E - 0 1 1.2 2 E - 0 5 1.0 0 E + 0 4 2. 2 1 E - 0 1 5. 3 9 E - 0 3 25 30 4 . 6 0 49 0 . 2 0 6,4 7 7 0. 0 E + 0 0 3.5E-03 L X 11 0 5 4 3 He x a n e 4. 3 4 E + 0 1 2. 0 0 E - 0 1 7.7 7 E - 0 6 1.2 4 E + 0 1 6.8 2 E + 0 1 1.6 6 E + 0 0 25 34 1 . 7 0 50 8 . 0 0 6,8 9 5 0. 0 E + 0 0 2.0E-01 L 11 1 4 4 4 Bis ( 2 - c h l o r o e t h y l ) e t h e r 1. 5 5 E + 0 1 6. 9 2 E - 0 2 7.5 3 E - 0 6 1.7 2 E + 0 4 7. 3 6 E - 0 4 1. 8 0 E - 0 5 25 45 1 . 1 5 65 9 . 7 9 10 , 8 0 3 3.3 E - 0 4 0.0E+00 L 11 5 2 9 7 En d o s u l f a n 2. 1 4 E + 0 3 1. 1 5 E - 0 2 4.5 5 E - 0 6 5. 1 0 E - 0 1 4. 5 8 E - 0 4 1. 1 2 E - 0 5 25 67 4 . 4 3 94 2 . 9 4 14 , 0 0 0 0. 0 E + 0 0 2.1E-02 S X 11 8 7 4 1 He x a c h l o r o b e n z e n e 5. 5 0 E + 0 4 5. 4 2 E - 0 2 5.9 1 E - 0 6 5. 0 0 E - 0 3 5. 4 0 E - 0 2 1. 3 2 E - 0 3 25 58 2 . 5 5 82 5 . 0 0 14 , 4 4 7 4.6 E - 0 4 2.8E-03 S X 12 0 8 2 1 1, 2 , 4 - T r i c h l o r o b e n z e n e 1. 7 8 E + 0 3 3. 0 0 E - 0 2 8.2 3 E - 0 6 4.8 8 E + 0 1 5. 8 1 E - 0 2 1. 4 2 E - 0 3 25 48 6 . 1 5 72 5 . 0 0 10 , 4 7 1 0. 0 E + 0 0 2.0E-01 L 12 3 7 3 9 Cr o t o n a l d e h y d e ( 2 - b u t e n a l ) 4. 8 2 E + 0 0 9. 5 6 E - 0 2 1.0 7 E - 0 5 3.6 9 E + 0 4 7. 9 9 E - 0 4 1. 9 5 E - 0 5 25 37 5 . 2 0 56 8 . 0 0 9 5.4 E - 0 4 0.0E+00 L X 12 4 4 8 1 Ch l o r o d i b r o m o m e t h a n e 6. 3 1 E + 0 1 1. 9 6 E - 0 2 1.0 5 E - 0 5 2.6 0 E + 0 3 3. 2 0 E - 0 2 7. 8 1 E - 0 4 25 41 6 . 1 4 67 8 . 2 0 5,9 0 0 2.4 E - 0 5 7.0E-02 L X X 12 6 9 8 7 Me t h a c r y l o n i t r i l e 3. 5 8 E + 0 1 1. 1 2 E - 0 1 1.3 2 E - 0 5 2.5 4 E + 0 4 1. 0 1 E - 0 2 2. 4 6 E - 0 4 25 36 3 . 3 0 55 4 . 0 0 7,6 0 0 0. 0 E + 0 0 7.0E-04 L 12 6 9 9 8 2- C h l o r o - 1 , 3 - b u t a d i e n e ( c h l o r o p r e 6. 7 3 E + 0 1 8. 5 8 E - 0 2 1.0 3 E - 0 5 2.1 2 E + 0 3 4. 9 1 E - 0 1 1. 2 0 E - 0 2 25 33 2 . 4 0 52 5 . 0 0 8,0 7 5 0. 0 E + 0 0 7.0E-03 L 12 7 1 8 4 Te t r a c h l o r o e t h y l e n e 1. 5 5 E + 0 2 7. 2 0 E - 0 2 8.2 0 E - 0 6 2.0 0 E + 0 2 7. 5 3 E - 0 1 1. 8 4 E - 0 2 25 39 4 . 4 0 62 0 . 2 0 8,2 8 8 3.0 E - 0 6 0.0E+00 L 12 9 0 0 0 Py r e n e 1. 0 5 E + 0 5 2. 7 2 E - 0 2 7.2 4 E - 0 6 1.3 5 E + 0 0 4. 5 0 E - 0 4 1. 1 0 E - 0 5 25 66 7 . 9 5 93 6 14 3 7 0 0. 0 E + 0 0 1.1E-01 S X 13 2 6 4 9 Dib e n z o f u r a n 5. 1 5 E + 0 3 2. 3 8 E - 0 2 6.0 0 E - 0 6 3.1 0 E + 0 0 5. 1 5 E - 0 4 1. 2 6 E - 0 5 25 56 0 82 4 66 4 0 0 0. 0 E + 0 0 1.4E-02 S X 13 5 9 8 8 se c - B u t y l b e n z e n e 9. 6 6 E + 0 2 5. 7 0 E - 0 2 8.1 2 E - 0 6 3.9 4 E + 0 0 5. 6 8 E - 0 1 1. 3 9 E - 0 2 25 44 6 . 5 67 9 88 7 3 0 0. 0 E + 0 0 1.4E-01 L X 14 1 7 8 6 Eth y l a c e t a t e 6. 4 4 E + 0 0 7. 3 2 E - 0 2 9.7 0 E - 0 6 8.0 3 E + 0 4 5. 6 4 E - 0 3 1. 3 8 E - 0 4 25 35 0 . 2 6 52 3 . 3 76 3 3 . 6 6 0. 0 E + 0 0 3.2E+00 L X 15 6 5 9 2 cis - 1 , 2 - D i c h l o r o e t h y l e n e 3. 5 5 E + 0 1 7. 3 6 E - 0 2 1.1 3 E - 0 5 3.5 0 E + 0 3 1. 6 7 E - 0 1 4. 0 7 E - 0 3 25 33 3 . 6 5 54 4 71 9 2 0. 0 E + 0 0 3.5E-02 L X 15 6 6 0 5 tr a n s - 1 , 2 - D i c h l o r o e t h y l e n e 5. 2 5 E + 0 1 7. 0 7 E - 0 2 1.1 9 E - 0 5 6.3 0 E + 0 3 3. 8 4 E - 0 1 9. 3 6 E - 0 3 25 32 0 . 8 5 51 6 . 5 67 1 7 0. 0 E + 0 0 7.0E-02 L X 20 5 9 9 2 Be n z o ( b ) f l u o r a n t h e n e 1. 2 3 E + 0 6 2. 2 6 E - 0 2 5.5 6 E - 0 6 1. 5 0 E - 0 3 4. 5 4 E - 0 3 1. 1 1 E - 0 4 25 71 5 . 9 96 9 . 2 7 17 0 0 0 2.1 E - 0 4 0.0E+00 S X 21 8 0 1 9 Ch r y s e n e 3. 9 8 E + 0 5 2. 4 8 E - 0 2 6.2 1 E - 0 6 6. 3 0 E - 0 3 3. 8 7 E - 0 3 9. 4 4 E - 0 5 25 71 4 . 1 5 97 9 16 4 5 5 2.1 E - 0 6 0.0E+00 S X 30 9 0 0 2 Ald r i n 2. 4 5 E + 0 6 1. 3 2 E - 0 2 4.8 6 E - 0 6 1. 7 0 E - 0 2 6. 9 5 E - 0 3 1. 7 0 E - 0 4 25 60 3 . 0 1 83 9 . 3 7 15 0 0 0 4.9 E - 0 3 1.1E-04 S X 31 9 8 4 6 al p h a - H C H ( a l p h a - B H C ) 1. 2 3 E + 0 3 1. 4 2 E - 0 2 7.3 4 E - 0 6 2.0 0 E + 0 0 4. 3 4 E - 0 4 1. 0 6 E - 0 5 25 59 6 . 5 5 83 9 . 3 6 15 0 0 0 1.8 E - 0 3 0.0E+00 S 54 1 7 3 1 1, 3 - D i c h l o r o b e n z e n e 1. 9 8 E + 0 3 6. 9 2 E - 0 2 7.8 6 E - 0 6 1.3 4 E + 0 2 1. 2 7 E - 0 1 3. 0 9 E - 0 3 25 44 6 68 4 92 3 0 . 1 8 0. 0 E + 0 0 1.1E-01 L X 54 2 7 5 6 1, 3 - D i c h l o r o p r o p e n e 4. 5 7 E + 0 1 6. 2 6 E - 0 2 1.0 0 E - 0 5 2.8 0 E + 0 3 7. 2 4 E - 0 1 1. 7 7 E - 0 2 25 38 1 . 1 5 58 7 . 3 8 79 0 0 4.0 E - 0 6 2.0E-02 L 16 3 4 0 4 4 MT B E 7. 2 6 E + 0 0 1. 0 2 E - 0 1 1.0 5 E - 0 5 5.1 0 E + 0 4 2. 5 6 E - 0 2 6. 2 3 E - 0 4 25 32 8 . 3 49 7 . 1 66 7 7 . 6 6 0. 0 E + 0 0 3.0E+00 L 74 3 9 9 7 6 Me r c u r y ( e l e m e n t a l ) 5. 2 0 E + 0 1 3. 0 7 E - 0 2 6.3 0 E - 0 6 2.0 0 E + 0 1 4. 4 0 E - 0 1 1. 0 7 E - 0 2 25 62 9 . 8 8 17 5 0 14 1 2 7 0. 0 E + 0 0 3.0E-04 L 6 o f 8 VL O O K U P T A B L E S 7 o f 8 VL O O K U P T A B L E S 8 o f 8 APPENDIX D SAMPLE DATA ENTRY SHEETS FOR EACH MODEL D-1 DA T A E N T R Y S H E E T ( S L - S C R E E N ) CA L C U L A T E R I S K - B A S E D S O I L C O N C E N T R A T I O N ( e n t e r " X " i n " Y E S " b o x ) YE S X OR CA L C U L A T E I N C R E M E N T A L R I S K S F R O M A C T U A L S O I L C O N C E N T R A T I O N ( e n t e r " X " i n " Y E S " b o x a n d i n i t i a l s o i l c o n c . b e l o w ) YE S EN T E R EN T E R In i t i a l Ch e m i c a l so i l CA S N o . co n c . , (n u m b e r s o n l y , C R no d a s h e s ) (µg/ k g ) Ch e m i c a l SL - S C R E E N Ve r s i o n 3 . 0 ; 0 2 / 0 3 Re s e t t o De f a u l t s 71 4 3 2 Be n z e n e MO R E DA T A E N T R Y S H E E T ( S G - A D V ) SL - A D V CA L C U L A T E R I S K - B A S E D S O I L C O N C E N T R A T I O N ( e n t e r " X " i n " Y E S " b o x ) Ve r s i o n 3 . 0 ; 0 2 / 0 3 YE S X Re s e t t o O R De f a u l t s CA L C U L A T E I N C R E M E N T A L R I S K S F R O M A C T U A L S O I L C O N C E N T R A T I O N (en t e r " X " i n " Y E S " b o x a n d i n i t i a l s o i l c o n c . b e l o w YE S EN T E R EN T E R In i t i a l Ch e m i c a l so i l CA S N o . co n c . , (n u m b e r s o n l y , C R no d a s h e s ) (µg /k g) Ch e m i c a 71 4 3 2 Be n z e n e MO R E DA T A E N T R Y S H E E T ( S G - S C R E E N ) SG - S C R E E N Ve r s i o n 2 . 0 ; 0 2 / 0 3 So i l G a s C o n c e n t r a t i o n D a t a Re s e t t o De f a u l t s EN T E R EN T E R EN T E R So i l So i l Ch e m i c a l ga s OR ga s CA S N o . co n c . , co n c . , (n u m b e r s o n l y , C g C g no d a s h e s ) (µg/ m 3 ) (p p m v ) Ch e m i c a l 71 4 3 2 2. 0 0 E + 0 1 Be n z e n e MO R E DA T A E N T R Y S H E E T ( S G - A D V ) SG - A D V Ve r s i o n 2 . 0 ; 0 2 / 0 3 So i l G a s C o n c e n t r a t i o n D a t a Re s e t t o EN T E R EN T E R EN T E R De f a u l t s So i l So i l Ch e m i c a l ga s ga s CA S N o . co n c . , OR co n c . , (n u m b e r s o n l y , C g C g no d a s h e s ) (µg/ m 3 ) (p p m v ) Ch e m i c a l 71 4 3 2 2. 0 0 E + 0 1 Be n z e n e EN T E R EN T E R EN T E R EN T E R EN T E R EN T E R EN T E R EN T E R De p t h To t a l s m u s t a d d u p t o v a l u e o f L s (ce l l F 2 4 ) So i l be l o w g r a d e So i l g a s Th i c k n e s s Th i c k n e s s st r a t u m A Us e r - d e f i n e d to b o t t o m sa m p l i n g Av e r a g e Th i c k n e s s of s o i l of s o i l SC S str a t u m A of e n c l o s e d de p t h so i l of s o i l st r a t u m B , str a t u m C , so i l t y p e so i l v a p o r sp a c e f l o o r , be l o w g r a d e , te m p e r a t u r e , str a t u m A , (E n t e r v a l u e o r 0 ) (E n t e r v a l u e o r 0 ) (u s e d t o e s t i m a t e OR pe r m e a b i l i t y , L F L s T S h A h B h C so i l v a p o r k v (c m ) (c m ) (o C) (c m ) (c m ) (c m ) pe r m e a b i l i t y ) (c m 2 ) 20 0 40 0 10 20 0 10 0 10 0 L MO R E GW - S C R E E N Ve r s i o n 3 . 0 ; 0 2 / 0 3 Re s e t t o De f a u l t s DA T A E N T R Y S H E E T ( G W - S C R E E N ) CA L C U L A T E R I S K - B A S E D G R O U N D W A T E R C O N C E N T R A T I O N ( e n t e r " X " i n " Y E S " b o x ) YE S X OR CA L C U L A T E I N C R E M E N T A L R I S K S F R O M A C T U A L G R O U N D W A T E R C O N C E N T R A T I O N (e n t e r " X " i n " Y E S " b o x a n d i n i t i a l g r o u n d w a t e r c o n c . b e l o w YE S EN T E R EN T E R In i t i a l Ch e m i c a l gr o u n d w a t e r CA S N o . co n c . , (n u m b e r s o n l y , C W no d a s h e s ) (µg/ L ) Ch e m i c a l 71 4 3 2 Be n z e n e MO R E DA T A E N T R Y S H E E T ( G W - A D V ) CA L C U L A T E R I S K - B A S E D G R O U N D W A T E R C O N C E N T R A T I O N ( e n t e r " X " i n " Y E S " b o x ) YE S X OR CA L C U L A T E I N C R E M E N T A L R I S K S F R O M A C T U A L G R O U N D W A T E R C O N C E N T R A T I O N ( e n t e r " X " i n " Y E S " b o x a n d i n i t i a l g r o u n d w a t e r c o n c . b e l o w YE S EN T E R EN T E R In i t i a l Ch e m i c a l gr o u n d w a t e r CA S N o . co n c . , (n u m b e r s o n l y , C W no d a s h e s ) (µg/ L ) Ch e m i c a l 71 4 3 2 Be n z e n e GW - A D V V er s i o n 3 . 0 ; 0 2 / 0 3 Re s e t t o De f a u l t s MO R E APPENDIX E BIBLIOGRAPHY AND REFERENCE LIST E-1 American Petroleum Institute (API). 1998. 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E-10 INTERIM FINAL GUIDANCE FOR THE EVALUATION AND MITIGATION OF SUBSURFACE VAPOR INTRUSION TO INDOOR AIR Department of Toxic Substances Control California Environmental Protection Agency December 15, 2004 (Revised February 7, 2005) State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 ii ACKNOWLEDGEMENTS Preparation of this guidance was achieved through the efforts of the following individuals at the Department of Toxic Substances Control: Karen Baker Supervising Engineering Geologist David Berry Senior Toxicologist Craig Christmann Senior Engineering Geologist Frank Dellechaie Senior Engineering Geologist Tina Diaz Senior Hazardous Substances Scientist Dan Gallagher Senior Engineering Geologist Kimi Klein Staff Toxicologist Marsha Mingay Senior Public Participation Specialist Brad Parsons Senior Hazardous Substances Scientist Laura Rainey Senior Engineering Geologist Mike Schum Staff Toxicologist Mike Sorensen Supervising Hazardous Substances Engineer II Jesus Sotelo Hazardous Substances Engineer Ann Stacy Air Pollution Specialist Fred Zanoria Senior Engineering Geologist Additional assistance was provided by Roger Brewer of the San Francisco Regional Water Quality Control Board, John Moody of the United States Environmental Protection Agency (Region IX), and Jim Carlisle and Page Painter of the Office of Environmental Health Hazard Assessment. We thank them for their substantial contribution towards the completion of this document. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 iii EXECUTIVE SUMMARY The intrusion of subsurface vapors into buildings is one of many exposure pathways that must be considered in assessing the risk posed by releases of hazardous chemicals into the environment. The Department of Toxic Substances Control (DTSC) in this guidance document recommends an approach for evaluating vapor intrusion into buildings and its subsequent impact on indoor air quality. Approaches for the mitigation of vapor intrusion are also discussed. Step-Wise Approach If volatile organic compounds (VOCs) are present in the subsurface at a site, the vapor intrusion pathway should be evaluated along with the exposure pathways identified in other guidance (Preliminary Endangerment Assessment (PEA) Guidance Manual, DTSC, reprinted 1998; Risk Assessment Guidance for Superfund (RAGS), Volume 1 Human Health Evaluation Manual, Part A, United States Environmental Protection Agency (USEPA) 1989). This approach is applicable to both Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) sites and Resource Conservation and Recovery Act (RCRA) facilities. Due to the complexity of vapor intrusion, many professional disciplines may be needed to evaluate and mitigate exposure. Accordingly, an appropriate project team should be gathered for all vapor intrusion issues. The DTSC recommends a step-wise approach as discussed below and depicted in Figure 1 for the evaluation of vapor intrusion. For sites with existing buildings, Steps 1 through 11 apply. For sites with proposed buildings, Steps 1 through 3, 5, 6, 7, and 11 apply. • Step 1 – Identify the spill(s) or release(s). • Step 2 – Characterize the site. • Step 3 – Identify the site as one where vapor intrusion into indoor air may represent a complete exposure pathway (VOCs are detected in the subsurface). • Step 4 – For an existing building, identify whether an imminent hazard exists from vapors migrating into indoor air. If none exists, • Step 5 – Perform a screening evaluation using the provided default vapor attenuation factors. If a potential risk exists, • Step 6 – Collect additional site data. • Step 7 – Perform a modeling evaluation using site-specific physical parameters and building parameters as appropriate. If the calculated risk is still significant, • Step 8 – For an existing building, prepare an indoor air sampling workplan, which includes an assessment of the utility corridors and the development of a contingency plan for appropriate response actions. Also, conduct appropriate public outreach with the affected community. • Step 9 – For an existing building, conduct indoor air sampling. • Step 10 – For an existing building, evaluate the data to determine if the indoor air concentrations are acceptable. If they are not, • Step 11a – For an existing building, mitigate indoor air exposure, implement engineering controls, and remediate the VOC contamination as appropriate. • Step 11b - If no building exists on the site, and the calculated risk is significant, remediate subsurface VOC contamination or implement institutional measures to assure that engineering controls are installed in any future buildings. • Step 11c - For both circumstances, institute long-term monitoring at the site. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 iv Steps 1, 2 and 3 – Identifying spills, characterizing the site, and evaluating if the vapor intrusion exposure pathway is complete Steps 1 and 2 are common to all site investigations, and only guidance for performing these steps when VOCs have been found in the subsurface are discussed here. With respect to Step 3, if VOCs are detected in the subsurface near or adjacent to existing or proposed buildings, then the site should be considered one where the vapor intrusion exposure pathway may be complete. Step 4 – For an existing, occupied building, identifying an imminent hazard from VOCs migrating into indoor air from the subsurface The identification of an imminent hazard is based on the presence of odors in the building under investigation and observing illnesses in building occupants (headache, eye irritation, nausea, dizziness, etc.) that may be linked to inhaling hazardous vapors indoors. If any of these circumstances exist, it may be necessary to consider the evacuation of the building. Step 5 - Performing a Preliminary Screening Evaluation for Vapor Intrusion A preliminary evaluation should be conducted using the attenuation factors provided by DTSC in this guidance document. With the subsurface contaminant concentrations and default attenuation factors, the associated contaminant concentrations in indoor air can be determined. Default attenuation factors are provided for the following building scenarios: • Existing residential slab-on-grade buildings • Existing residential buildings with crawl spaces • Existing residential buildings with basements • Existing commercial buildings • Future residential slab-on-grade buildings • Future residential buildings with crawl spaces • Future residential buildings with basements • Future commercial buildings The following conditions apply on the use of the default attenuation factors: • Soil gas measurements should be used. • Maximum contaminant concentrations should be used. • Fractured bedrock or other preferential pathways should not exist at the site. • California toxicity factors should be used. • Cumulative health effects should be calculated. The screening evaluation for vapor intrusion should be included as part of the PEA for a site or facility. As discussed by the USEPA in their risk assessment guidance (USEPA RAGS, 1989), the risks from each chemical and from all applicable exposure pathways should be summed to obtain the overall screening level risk posed by chemicals detected at the facility/site. Additionally, pursuant to Senate Bill 32 (SB 32), the California Land Environmental Restoration and Reuse Act, the Office of Environmental Health Hazard Assessment State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 v (OEHHA) published a list of screening numbers. Numerous exposure pathways were evaluated in calculating the SB 32 screening numbers, including the exposure pathway of inhaling indoor air contaminated with vapors intruding from the subsurface. The OEHHA screening numbers may be used to evaluate sites for vapor intrusion but only with an understanding of the assumptions and limitations of the screening numbers, as indicated in the OEHHA Advisory Document and its associated User’s Guide. In addition, the OEHHA screening numbers can be used as a mechanism to assist in the prioritization of work. Occupational Safety and Health Administration (OSHA) permissible exposure limits (PELs) are not appropriate exposure endpoints in occupational settings for indoor air degraded by subsurface contamination. However, this guidance does not apply to operations that are directly regulated by OSHA (e.g., spray booths, plating operations, etc.). Steps 6 and 7 - Collecting Additional Site Data and Performing a Site-Specific Vapor Intrusion Evaluation If a potentially significant risk is calculated in the preliminary screening evaluation, further investigation may include the following: • Collecting data to define site-specific soil physical and chemical parameters using recommended test methods. • Collecting soil gas samples to define the vapor plume at sites where buildings do not exist or near or beneath buildings using current guidelines. • Statistically evaluating the environmental media data to derive the appropriate contaminant concentration to be used in a site-specific assessment. • Collecting subslab soil gas samples or crawl space samples at an existing building. With additional information and data, the risk associated with vapor intrusion can be evaluated with the USEPA Vapor Intrusion Model. Steps 8, 9 and 10 – Conducting Building Screening, Collecting Indoor Air Samples and Determining if Indoor Air Concentrations are Acceptable (Existing Buildings) If the site-specific evaluation shows that buildings are subject to vapor intrusion, the occupants of these buildings must be notified. During the notification process, information should be collected concerning the buildings, such as occupancy, preferential migration pathways, consumer product usage, and building characteristics. After the notification process, indoor air samples should be collected and the human-health risk quantified. Buildings should be sampled twice over a six month period before a final risk determination is conducted. DTSC does not recommend the use of isolation emission flux chamber data for the determination of risk associated with vapor intrusion. Flux chambers may only be used to qualitatively evaluate the flux of vapors migrating from the subsurface into buildings. Step 11 – Mitigating Indoor Air Exposure and Conducting Long-Term Monitoring If the indoor air sampling yields unacceptable results, vapor intrusion must be mitigated. There are several remedies that may be considered where vapor intrusion poses a health risk, as follows: State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 vi • Removing VOC contamination through site remediation (cleanup). • Installing passive or active vent systems (existing buildings). • Installing passive vent systems and a membrane system (future buildings). • Installing active vent systems and a membrane system (future buildings). For any remedy chosen for a site, long-term monitoring of soil gas and indoor air may be necessary. The frequency of the monitoring will depend upon site-specific conditions and the degree of VOC contamination. At some sites, removal of all volatile chemicals from the subsurface will not be possible and institutional controls and engineering measures will be necessary to prevent potential exposure to subsurface vapors. Land use covenants will be required in these cases, which must include the following: • A description of the potential cause of the unacceptable risk. • A prohibition against construction without removal or treatment of contamination to approved risk-based levels. • The implementation and monitoring of appropriate engineered remedies to prevent vapor intrusion until risk-based cleanup levels have been met. This documentation should be recorded at the local County Recorder’s Office after approval by DTSC legal counsel. Additionally, land use covenants must include notification requirements to utility workers or contractors that may have contact with contaminated soil and groundwater while installing utilities or undertaking construction activities. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 vii TABLE OF CONTENTS ACKNOWLEDGEMENTS............................................................................................................ii EXECUTIVE SUMMARY............................................................................................................ iii INTRODUCTION..........................................................................................................................1 SCOPE.........................................................................................................................................1 VAPOR INTRUSION EVALUATION OVERVIEW ......................................................................2 VAPOR INTRUSION ASSESSMENT .........................................................................................2 Step 1: Site History and Identification of Spills and/or Releases..........................................2 Step 2: Site Characterization..................................................................................................3 Conceptual Site Model (CSM)..............................................................................................4 Soil Gas .................................................................................................................................5 Groundwater ..........................................................................................................................8 Soil Matrix..............................................................................................................................9 Passive Soil Gas .................................................................................................................10 Flux Chambers ....................................................................................................................11 Step 3: Is a Site a Candidate for Vapor Intrusion?.............................................................11 Step 4: Evaluation of Acute Hazard in for an Existing Building ..........................................12 Step 5: Preliminary Screening Evaluation............................................................................13 Attenuation Factors for Preliminary Screening Evaluations..............................................13 Use of Soil Matrix Concentrations......................................................................................14 Use of Groundwater Concentrations..................................................................................15 Use of Soil Gas Screening Numbers from the Office of Environmental Health Hazard Assessment .........................................................................................................................16 Use of Occupational Safety and Health Administration (OSHA) Standards ....................17 When A Preliminary Screening Evaluation Indicates An Unacceptable Risk ..................18 Step 6: Additional Site Characterization ..............................................................................18 Additional Soil Gas Sampling .............................................................................................18 Physical Characteristics of the Subsurface .......................................................................19 Subslab Soil Gas Sampling (Existing Building) .................................................................19 Sampling of Crawl Spaces (Existing Buildings).................................................................20 Step 7: Site-Specific Screening Evaluations........................................................................20 Use of USEPA Vapor Intrusion Model Spreadsheets .......................................................21 Attenuation Factors for Site-Specific Evaluations .............................................................21 Existing Building..................................................................................................................21 Future Buildings ..................................................................................................................22 Step 8: Indoor Air Sampling Assessment.............................................................................23 Site Visit...............................................................................................................................23 Utility Corridor Assessment ................................................................................................24 Indoor Air Samples..............................................................................................................25 Data Quality Objective Process..........................................................................................26 Air Sampling Analytical Methods........................................................................................27 Contingency Planning .........................................................................................................29 Indoor Air Sampling Workplan............................................................................................30 Step 9: Indoor Air Sampling..................................................................................................30 Building Screening for Preferential Pathways ...................................................................31 Building Screening for Consumer Products .......................................................................32 Indoor Air Sampling.............................................................................................................32 Ambient (Outdoor) Air Samples..........................................................................................33 Quality Assurance/Quality Control .....................................................................................34 Step 10: Evaluation of Indoor Air Sampling Results............................................................35 State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 viii Response Action and Contingency Planning.....................................................................35 Step 11: Mitigate Indoor Air Exposure, Monitoring, and Implementation of Engineering Controls...................................................................................................................................35 Mitigation Measures............................................................................................................36 Excavation of VOC Sources ...............................................................................................36 Existing Building Retrofit - VOC Collection and Passive Vent Systems (Without Membrane) .............................................................................................................................................36 Future Building Construction - VOC Collection, Membrane, and Passive Vent Systems ....37 Future Building Construction - VOC Collection, Membrane, and Active Vent Systems.......38 O&M Requirements for Venting Systems ..........................................................................39 Permanent Soil Gas Monitoring Points ..............................................................................39 Perimeter Monitoring at a Facility.......................................................................................40 Institutional Controls and Deed Restrictions......................................................................40 BIODEGRADATION OF VOLATILE PETROLEUM HYDROCARBONS.................................41 CONFIRMATION SAMPLING FOR THE COMPLETION OF REMEDIATION........................42 REPORTING OF VAPOR INTRUSION ....................................................................................42 PUBLIC OUTREACH.................................................................................................................44 Introduction.............................................................................................................................44 Public Meetings ......................................................................................................................44 REFERENCES...........................................................................................................................46 FIGURES FIGURE 1 – VAPOR INTRUSION TO INDOOR AIR ASSESSMENT.....................................52 FIGURE 2 – DIAGRAM OF AIR FLOW THROUGH A BUILDING...........................................53 FIGURE 3 – UTILITY CORRIDOR DECISION TREE..............................................................54 TABLES TABLE 1 - List of Chemicals to be Considered for the Vapor Intrusion Pathway .......................55 TABLE 2 - Attenuation Factors for Preliminary Screening Evaluations (Step 5).........................58 TABLE 3 - Input Parameters for Site-Specific Screening Evaluations (Step 7)..........................59 APPENDICES APPENDIX A - FLUX CHAMBERS IN RISK DETERMINATION…………………………… A - 1 APPENDIX B - DEFAULT ATTENUATION FACTORS……………………………………….B - 1 APPENDIX C - HUMAN RISK ASSESSMENT………………………………………………...C - 1 APPENDIX D - OVERVIEW OF THE JOHNSON AND ETTINGER MODEL……………... D - 1 APPENDIX E - SOIL GAS CONCENTRATIONS FOR SOIL MATRIX ANALYTICAL RESULTS……………………………………………………………………….. E - 1 APPENDIX F - USE OF PERMISSIBLE EXPOSURE LIMITS……………………………… F - 1 APPENDIX G - SOIL GAS SAMPLING DIRECTLY UNDER BUILDING FOUNDATIONS (SUBSLAB SAMPLING)………………………………………………………. G - 1 APPENDIX H - SOIL LABORATORY MEASUREMENTS………………………………....... H - 1 APPENDIX I - IN-SITU AIR PERMEABILITY MEASUREMENTS…………………….….... I - 1 APPENDIX J - EXAMPLE ACCESS AGREEMENT……………………………………………. J - 1 APPENDIX K - BUILDING SURVEY FORM……………………………….……………………. K - 1 APPENDIX L - HOUSEHOLD PRODUCTS INVENTORY FORM..……………………........ l - 1 State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 1 INTRODUCTION Volatile organic chemicals (VOCs) in the subsurface, whether in soil or groundwater, can migrate upward through the soil and enter into buildings, causing an unacceptable chemical exposure for building occupants. The California Department of Toxic Substances Control (DTSC) requires that the human health risk be evaluated at sites under its oversight and, if VOCs are present, exposure from vapor intrusion should be included in the human health risk evaluation. Evaluation of the indoor air exposure pathway involves characterizing subsurface VOC plumes, obtaining appropriate environmental data, using fate and transport models to predict indoor air concentrations from vapor intrusion, and conducting indoor air sampling, if necessary. This Guidance outlines the technical aspects of evaluating this exposure pathway and provides recommendations on elements that should be included in a facility investigation. Due to the complexity of vapor intrusion, many professional disciplines may be needed to evaluate and mitigate exposure. Accordingly, an appropriate project team should be gathered when evaluating vapor intrusion issues. DTSC anticipates that this Guidance will be used by regulators, responsible parties, environmental consultants, community groups, and property developers. Because vapor intrusion is a developing field, many technical aspects are not well understood. Hence, it is anticipated that many of the procedures and practices within this Guidance will change as our understanding of vapor intrusion progresses. DTSC will update this document as needed to accommodate refinements and advances in our understanding. SCOPE This Guidance, along with the vapor intrusion guidance from the United States Environmental Protection Agency (USEPA, 2002a), provides technically defensible and consistent approaches for evaluating vapor intrusion to indoor air, based upon the current understanding of this exposure pathway. Please recognize that this guidance document is not regulation. This Guidance does not impose any requirements or obligations on the regulated community but provides a technical framework for evaluating vapor intrusion. Other technically equivalent procedures may exist, and this Guidance is not intended to exclude alternate approaches or methodologies. Hence, users of this guidance document are free to use other technically sound approaches. This Guidance addresses the following questions: • What sites are candidates for vapor intrusion to indoor air? • What site characterization data are needed to conduct a vapor intrusion evaluation? • What are the data requirements for an evaluation of indoor air exposure? • What sites pose an imminent threat and warrant immediate action due to vapor intrusion? • What is the human health risk associated with vapor intrusion? • When should indoor air sampling be conducted? • When are mitigation measures necessary to prevent indoor air exposure? • When are long-term soil gas and indoor air monitoring required? This Guidance only addresses the evaluation of a single exposure pathway of vapor intrusion to indoor air. However, when evaluating the human and ecological risk associated with releases of hazardous chemicals to the environment, all potential exposure pathways State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 2 should be evaluated and the results reported to DTSC. Mitigation of contaminant exposure must be conducted with an understanding of all exposure pathways, not just the vapor intrusion pathway. As such, this Guidance supplements DTSC’s Preliminary Endangerment Assessment (PEA) Guidance Manual (DTSC, 1994) and USEPA’s Risk Assessment Guidance for Superfund (USEPA, 1989). VAPOR INTRUSION EVALUATION OVERVIEW Figure 1 shows the step-wise approach for evaluating vapor intrusion, and the associated steps are described in the following text. DTSC recommends that a team of technical professionals be gathered when evaluating the exposure pathway. The core team should consist of a geologist, a toxicologist, and an engineer. Since this document cannot address all circumstances, the team can provide technical and management judgment when encountering unusual or complex issues. The step-wise approach in this guidance document is meant to be flexible and may be tailored to site-specific circumstances. Although volatile chemicals may be present in the subsurface beneath a building, if contaminant vapors do not enter the building, the exposure pathway from the contaminant source to the building occupant (receptor) is deemed incomplete, and the receptors cannot be considered at risk for vapor intrusion. Likewise, subsurface vapors may enter the building but be present at such low levels that the risk is negligible. However, vapors may migrate into a building and accumulate at levels that pose a human health threat. Figure 2 shows a simplified conceptual diagram of vapor intrusion. Methane is not specifically addressed in this Guidance, although some of the procedures described may apply. VAPOR INTRUSION ASSESSMENT For sites with existing buildings, DTSC recommends that Steps 1 – 11 be followed. For sites where no buildings exist but may potentially be built, DTSC recommends that Steps 1 – 3, 5, 6, 7, and 11 be followed (Figure 1). While the assessment process is presented in a step-wise fashion, the vapor intrusion pathway may be evaluated in an iterative manner. Step 1: Site History and Identification of Spills and/or Releases A comprehensive evaluation of the current and historical operations at a site should be conducted. Compilation of complete site information is essential for identifying all exposure pathways. DTSC recommends that record reviews be conducted to identify all Areas of Potential Concern (AOPCs) which might affect indoor air quality. For example, all historical documents should be reviewed to identify the potential locations of releases of the hazardous chemicals to the environment. These documents include, but are not limited to: • Regulatory Agency Files. Agency files contain information on hazardous chemical releases to the environment. Appropriate agencies to contact are DTSC, USEPA, State Water Resources Control Board (SWRCB), Regional Water Quality Control Boards (RWQCBs), county environmental health departments, city environmental health departments, and local fire departments. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 3 • Site Owner and Operator Records. Facility records are the primary source of information concerning the handling of hazardous chemicals. Owner/Operator files may include such records as product purchase invoices, waste manifests, permits, material safety data sheets (MSDS), safety plans, spill prevention plans, regulatory violations, and product inventory reports. • Maps and Photographs. Maps and photographs should be reviewed to determine the physical setting of a site and to identify prior property uses. Aerial photographs, historical photographs, and insurance maps should be checked to determine prior site use. Site inspections should be conducted to locate areas where chemicals were potentially released into the environment. The site inspection should include a walk-through of all known and potential areas of operation. Observations during the site inspection should focus on identifying hazardous materials and hazardous waste management units. Some of the physical features that are indicative of AOPCs are: • Storage tanks and storage areas • Areas with odors • Waste piles • Pools of liquid • Electrical or hydraulic equipment • Unidentified containers • Drains and sumps • Stained soil and pavement • Degraded floors and walls • Pits, ponds, and lagoons • Dry wells and injection wells • Septic systems • Loading docks or waste transfer areas • Waste processing areas • Solvent dipping tanks • Production lines All physical features that are unique to the vapor intrusion pathway should be noted during the site inspection. All buildings at a site should be inventoried along with their foundation types (basement, slab-on-grade, crawl space, or earthen floor) and foundation condition. The building dimensions should be noted along with the building construction date. All potential preferential pathways for vapor migration should be documented. Examples of preferential pathways include piping and utility corridors, floor drains, foundation construction joints, and elevator shafts. Uses of adjacent properties should be determined due to potential offsite migration of subsurface contaminant plumes. Additional guidance on the evaluation of site history and the identification of spill and releases can be found in the DTSC PEA Guidance Manual (1994). Step 2: Site Characterization Characterization of contamination should be conducted in the lateral and vertical directions through subsurface sampling. Likewise, the subsurface should be tested for all chemicals- of-concern (COCs) as determined through the site inspection process. For the vapor State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 4 intrusion pathway, exposure to subsurface contamination is best characterized through the collection of soil gas samples. When there is known or potential groundwater contamination, water samples should also be collected to evaluate the aquifer’s ability to degas VOCs, which potentially may cause a vapor intrusion risk. When evaluating exposure risk to subsurface contamination, a conceptual site model (CSM) should be developed and submitted to DTSC. Contaminant characterization data needed for vapor intrusion evaluation and the associated CSM are described below. Conceptual Site Model (CSM) The CSM is part of all site investigations. The purpose of a CSM is to provide a conceptual understanding of the potential for exposure to hazardous contaminants at a site based on the sources of contamination, the release mechanisms, the transport media, the exposure pathways, and the potential receptors. The CSM should include a diagrammatic or schematic presentation that relates the source of contamination to human receptors and identifies all the potential sources of contamination, the potentially contaminated media, and exposure pathways. The CSM organizes and communicates information about the site characteristics and is a necessary component of any health risk assessment. DTSC recommends that the following items be included in a CSM for the vapor intrusion pathway: • Primary Sources of Contamination. For each potential contaminant source, describe the industrial settings that potentially caused the contamination and provide a list of chemicals released into the environment for all such settings. • Primary Release Mechanism. For each potential contaminant source, describe the means by which the release, or suspected release, is thought to have occurred. • Secondary Sources of Contamination. Include all the environmental media potentially contaminated by the primary sources, such as surface soil, subsurface soil, and groundwater. Contaminated building materials, such as concrete foundations, can also be a source for vapor intrusion. • Contaminant Transport Mechanisms. For each potentially contaminated medium, describe the transport methods to indoor air, which are usually advection and diffusion through the vadose zone, and describe the character of the subsurface through which the contaminants must move. • Environmental Exposure Media and Exposure Routes. At sites where buildings exist, describe the character of the buildings where vapors may accumulate and any preferential contaminant migration pathways associated with the buildings, such as foundation crack, voids, utility ports, pipes, elevator shafts, sumps, and drain holes. • Potential Receptors. List all the current and future receptors that could potentially contact contaminated indoor air. In documenting current site conditions, a CSM should be supported by maps, subsurface cross sections, foundation details, and site diagrams. The narrative description should clearly describe known site conditions and state what assumptions were made to generate the CSM. The narrative should include a description of ambient sources and presence of State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 5 nearby potential sources of VOCs, such as soil vapor extraction systems. As additional data are collected and analyzed through the evaluation of the vapor intrusion pathway, the CSM should be updated and distributed to interested parties. The CSM should be an essential decision-making and communication tool for all interested parties. Additional information on the development of a CSM be found in guidance published by the United States Department of Energy (1997). Soil Gas Soil gas data should be used to evaluate vapor intrusion to indoor air. Soil gas data are recommended over other data, such as soil matrix and groundwater data, because soil gas data represent a direct measurement of the contaminant that will migrate into indoor air. In order to evaluate vapor intrusion, soil matrix and groundwater data must be converted to vapor concentrations using assumptions about the partitioning of the contaminant into the gas phase. While partitioning equations are readily available, using them increases the uncertainty in evaluating vapor intrusion. DTSC views this increased uncertainty as unacceptable in any indoor air evaluation. Hence, soil gas is the preferred contaminant data to use for calculating the risk from the vapor intrusion pathway. This preference for soil gas data to evaluate vapor intrusion is shared by USEPA (2002) and Johnson and Deize-Abreu (2003). In addition, it may be necessary to collect soil gas samples at two distinct time intervals to compensate for the effects of weather events, such as recent rainfall or barometric fluctuations. Ideally, for sites subject to vapor intrusion, permanent vadose monitoring points for sample collection should be installed to evaluate the long-term behavior of contaminated soil gas. The California Environmental Protection Agency’s (Cal-EPA) Soil Gas Advisory (2003) provides procedures for obtaining high-quality soil gas samples for use in risk assessments. The Advisory recommends the following field activities during the collection of soil gas samples: • Sample greater than 5 feet below grade to reduce the effects of barometric pumping. • Seal the surface around the soil gas sampler to prevent ambient air intrusion. • Conduct leak tests using tracer gas to evaluate ambient air intrusion. • Conduct tests to determine the optimal purge volume for sampling. • Purge and sample at low flow rates (less than 200 milliliters per minute). • Collect samples in Summa™ canisters (USEPA TO Methods), glass bulbs, or glass syringes. • Avoid soil gas sample collection following significant rainfall events. Soil gas samples should be collected to delineate the lateral and vertical extent of the subsurface contamination. Open areas at sites should be sampled first, and the sampling should continue towards buildings as indicated by the field data. Also, open areas that are covered with pavement should be sampled as a way to determine if vapors can accumulate underneath structures. When contaminated soil gas is encountered near buildings, soil gas samples should be collected around the perimeter of the building, as close as possible to the foundation. Soil gas samples from preferential pathways, such as utility corridors, should also be collected. Characterization should continue until non-detectable concentrations of VOCs are encountered in the subsurface laterally and vertically. The soil gas samples should be analyzed by gas chromatography / mass spectrometry (GC/MS) methods. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 6 The minimum amount of soil gas sampling needed in the vertical direction to evaluate vapor intrusion is the collection of soil gas samples at 5 and 15 to 20 feet below surface grade. Ideally, subsurface plumes should be delineated laterally and vertically with soil gas samples. In cases where previous characterization activities have taken place with soil matrix sampling without regard for vapor intrusion, additional characterization with soil gas sampling may be warranted. In these cases, the minimum level of soil gas sampling would be sample collection at 5 and 15 to 20 feet below surface grade. Soil gas samples should not be collected depths shallower than 5 feet in order to minimize barometric pumping effects. Deeper samples should be collected as needed to define vertical trends in vapor concentrations. For sites that overlie contaminated groundwater, an effort should be made to collect soil gas samples from immediately above the capillary fringe zone and half-way to the surface. For sites where the depth to groundwater is less than five feet, an attempt should be made to collect soil gas samples from beneath existing building foundations or similar settings, such as garage floors, patios, parking lots, roads, and other areas that are covered with pavement, concrete or a similar material, as a mechanism to evaluate the potential for vapor accumulation. The following should be considered when collecting soil gas samples: 1) Soil Gas Probes. As appropriate, permanent, semi-permanent, or temporary vadose zone probe points should be installed and monitored to determine temporal soil gas trends. However, during probe installation, subsurface conditions are disturbed. To allow for subsurface conditions to equilibrate, sampling from direct-push probes should not occur for at least 20 to 30 minutes after probe installation and sampling from probe installed with hollow-stem drilling methods should not occur for at least 48 hours after probe installation. Otherwise, the soil gas samples may not be representative of subsurface conditions. For soil gas sample collection, the quality assurance and quality control procedures in Cal-EPA (2003) and Los Angeles RWQCB (1997) should be followed. 2) Sampling Density. For sites seeking agency closure with unrestricted future land use, the residual concentrations of VOCs in the subsurface should be protective of residential receptors. Therefore, soil gas sampling locations should be sufficiently dense to effectively evaluate residential building scenarios. Ideally, there should be a soil gas sample for every potential future residential building. The parcel size for most residential housing tracts in California is approximately a quarter acre. Hence, soil gas sampling for future residential developments should be conducted on a quarter acre spacing. Soil gas samples should be collected until the soil gas contaminant plume is fully delineated and a clean zone of 100 feet beyond the extent of the soil gas plume is demonstrated (see Step 3, Criterion Two). For sites where current and future land use will be restricted by a land use covenant, the soil gas sampling density can be increased as a function of the size of the future buildings pursuant to the land use covenant. 3) Collection of Duplicates. When collecting soil gas samples with glass bulbs or glass syringes and analyzing the gas samples for VOCs by Method 8260B (USEPA, 1996) modified for air analysis with a mobile laboratory, the results of the field work should be independently confirmed through the collection of duplicate soil gas samples in Summa™ canisters. The collection of duplicates will confirm the mobile laboratory State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 7 detection limits and identify other potential COCs at the site. DTSC recommends that ten percent of the soil gas samples collected in the field be confirmed with Summa™ canisters that are analyzed using TO-14A (USEPA, 1999a) or TO-15 (USEPA, 1999b), as appropriate. The Summa™ canister duplicates should be collected in areas of both high and low VOC concentrations. 4) Analytical Detection Limits. The analytical detection limits for the soil gas samples should be sufficiently low to adequately evaluate the vapor intrusion pathway. As a conservative approach, the analytical detection limits should be no higher than five hundred times the acceptable indoor air concentrations. Setting a detection limit at this level implies that a soil gas measurement taken at five feet below surface grade that has a non-detectable concentration of a VOC with a detection limit of five hundred times the acceptable indoor air concentration is protective of public health. This assumption is based upon the data gathered by OEHHA (2004). Hence, detection limits derived from this generic attenuation factor should be protective of public health in California. However, in certain site-specific situations, the analytical detection limits must be set lower than five hundred times the acceptable indoor air concentrations if the estimated vapor intrusion attenuation factor dictates the change. This may be the case for soil gas samples collected from depths shallower than five feet or for soil gas samples collected directly below foundation slabs. For chemicals known to exist in the subsurface, whether determined through direct measurement or historical records review, the chemicals should be evaluated for vapor intrusion even if the concentrations in soil gas concentrations are non-detectable. In these cases, the chemical should be evaluated at concentrations equal to the method detection limit. If the chemical is postulated to no longer exist in the subsurface due to biodegradation or volatilization, the analytical detection limits should be appropriately low to demonstrate that circumstance. 5) Low Flow Conditions. Since soil gas is the preferred data for making vapor intrusion evaluations, every attempt should be made to collect representative samples. However, it may not be possible to collect soil gas samples from the subsurface in some instances. Some examples include sites with a saturated vadose zone due to a shallow water table or sites underlain with clay-rich soil. For sites with postulated low air permeability, an attempt should always be made to collect soil gas rather than default to another sampling method. However, if soil gas sampling fails, soil matrix samples should be collected pursuant to USEPA Method 5035 (see below) and the vapor intrusion pathway must then be evaluated with soil matrix data along with the groundwater contaminant data, as appropriate. At a given soil gas sampling location point, two attempts should be made to obtain a gas sample. If the first attempt fails, the sampling probe should be withdrawn and redriven a few feet over from the original location. DTSC considers soil gas sampling to fail when subsurface air flow rates are less than 10 milliliters per minute or when vacuum of 10 inches of mercury (136 inches of water) or greater is obtained. These low flow conditions must exist at numerous sampling points at a site before DTSC will consider the sampling efforts a failure. If groundwater is encountered during the collection of soil gas samples and it appears that the contamination is in close proximity to the water table, groundwater grab samples should be collected pursuant to USEPA (1997a) to evaluate the potential contaminant impact to the aquifer. If groundwater contamination exists at a site as documented by groundwater grab samples, the installation and sampling of permanent groundwater monitoring wells may be required by DTSC. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 8 During soil gas sampling, the collection of soil matrix samples should be considered for the evaluation of the physical character of the subsurface, such as total porosity, soil moisture, and dry bulk density (see Step 6). Groundwater When buildings exist over or near contaminated groundwater, vapor intrusion should be evaluated for this contaminant source. The risk associated with degassing of VOCs from the aquifer should be quantified. Thus, groundwater evaluation requires two steps. First, soil gas data should be collected over the areas of the contaminated groundwater, and the risk associated with the contaminated soil gas should be quantified. Second, groundwater data should be collected, and the risk associated with the contaminated groundwater should be quantified. Quantification of both risks is a way of evaluating which contamination source provides the greatest health threat. Cal-EPA (1995a,b) and USEPA (2002b) provide procedures for the installation of groundwater monitoring wells and the acquisition of groundwater VOC sample data. DTSC and USEPA guidance should be followed when collecting groundwater samples so that samples representative of aquifer conditions are collected. Some of the recommendations for data acquisition are: 1) Screen Placement. Contaminants at the top of the water table, rather than deeper contamination, are responsible for causing potential vapor intrusion problems. Hence, monitoring wells used to make vapor intrusion evaluations should be screened across the air-water interface, meaning the well screens should not be submerged below the top of the water table. 2) Screen Lengths. Monitoring wells with long well screens, regardless of screen placement, should not be used to make vapor intrusion evaluations. When sampling long well screens, clean water entering the well screen at depth may dilute the contaminated groundwater near the top of the screen, biasing the sampling results and the associated risk determination. Hence, short screen lengths are preferred for monitoring wells that will be used to make vapor intrusion evaluations. Ideally, the saturated thickness in a well screen should be less than 10 feet. 3) Well Installation. Monitoring wells should be designed and installed to yield representative samples of groundwater conditions. Monitoring wells should have proper filter packs, slot sizes, and annular seals. 4) Well Development. Monitoring wells should be developed to create an effective filter pack around the well screen, rectify damage to the formation caused by drilling, optimize hydraulic communication between the formation and well screen, and assist in the restoration of natural water quality of the aquifer near the well. 5) Well Purging. Prior to sampling, monitoring wells should be purged to remove stagnant casing water from the well that is not representative of aquifer conditions. Wells can be purged by removing the traditional three casing volumes prior to sampling or the well can be purged with low-flow techniques. For low-flow purging, DTSC recommends that the procedures of Puls and Barcelona (1995) be followed. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 9 6) Well Sampling. DTSC prefers bladder pumps or submersible pumps to sample groundwater for vapor intrusion evaluation. These pumps minimize the loss of VOCs during sample collection and handling. Likewise, groundwater can be sampled with diffusion bags following the procedures in Interstate Technology and Regulatory Council (2004). Other methods, such as peristaltic pumps and bailers, may cause unacceptable volatilization of chemicals. Peristaltic pumps can exert a strong negative pressure while sampling, potentially degassing the groundwater sample. Bailers may cause aeration of the sample due to continual disturbance of the well water upon sample retrieval. Soil Matrix When it is not possible to collect soil gas samples at a site due to low permeability conditions, vapor intrusion should be evaluated with soil matrix sample data and groundwater data, if the groundwater is contaminated. Soil matrix data are less than ideal for evaluating vapor intrusion risk because of the uncertainty associated with using partitioning equations and the potential loss of VOCs during sample collection. Human health risk calculated from soil matrix samples may be biased low due to inherent VOC escape during sample collection (Hewitt, 1994; Hewitt, 1999; Liikala et al., 1996; Vitale et al., 1999). However, in some cases, there may be no alternative. Interested parties should be cognizant of these factors when evaluating the vapor intrusion pathway with soil matrix samples. Although soil matrix data are not recommended for evaluating risk from vapor intrusion into indoor air, soil matrix data may be valuable for defining the source location and, thus, may be necessary to collect for site characterization purposes. When sampling soil for VOCs, the soil samples should be collected using the procedures with SW-846 Method A (USEPA, 2002c). DTSC has augmented USEPA Method 5035A procedures with additional guidance (DTSC, 2004b), which summarizes all the available soil sampling options. Both USEPA (2002c) and DTSC (2004) provide the minimum requirements and minimum standards to prevent loss of VOCs during sample collection and handling. DTSC encourages interested parties to read and understand both documents before implementing Method 5035A in the field. Generally, the options available for soil matrix sampling pursuant to Method 5035A are: 1) Chemical Preservation in the Field. Tared and labeled VOA vials with polytetrafluoroethylene (PTFE)-lined septum caps with appropriate chemical preservatives are taken into the field. The preservation fluid is either methanol or sodium bisulfate. The selection of the preservation fluid is based on the chemistry of the target compounds and soil, the desired method detection limits, and data quality objectives. The VOA vials with preservative are weighed in the field before sampling activities to verify no preservative loss. Soil subcores are obtained from appropriate sample locations using a field coring device. The soil subcores of appropriate mass are placed into the VOA vials in the field and capped, forming an airtight seal. The vials are re-weighed in the field to determine the sample weight. At the laboratory, the capped VOA vials are re-weighed to verify no preservative loss. The samples are prepared and analyzed with the caps in place. All preservatives, surrogates, internal standards, and matrix spikes are introduced through the PTFE-lined septum caps either manually or mechanically and analyzed with a closed-system purge-and-trap process. 2) Soil Sampling with Multi-Functional Sampling Devices. Multi-functional sampling devices (MFSDs) act as both a coring tool and airtight storage container. An example State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 10 of a MFSD is the EnCore™ Sampler or the Core N’ One Sampler1. With MFSDs, a small subcore of soil is collected directly into the volumetric storage chamber of the MFSD from a soil core or soil surface, filling it completely with zero headspace. The storage chamber is then capped to form an airtight seal. The intact MFSDs are sealed in a plastic bag for transport to the laboratory at 4 ± 2°C. 3) Empty Vial Technique in the Field. Empty, tared and labeled VOA vials with a PTFE- lined septum caps are taken into the field. The VOA vials do not contain chemical preservatives. Soil cores of appropriate mass are placed into the VOA vials in the field and capped, forming an airtight seal. At the laboratory, the capped VOA vials are re- weighed to obtain the weight of the soil samples. The samples are prepared and analyzed with the caps in place within 48 hours of sample collection. Otherwise, the vials should be frozen upon receipt at the laboratory and analyzed within seven days of sample collection. All preservatives, surrogates, internal standards, and matrix spikes are introduced through the PTFE-lined septum caps either manually or mechanically and analyzed with a closed-system purge-and-trap process. Soil samples should not be collected in large bottles, wide-mouthed jars, acetate liners, or brass sleeves. These are not appropriate containers under Method 5035A and are not appropriate sample collection devices for vapor intrusion evaluations. When characterizing subsurface contamination at a site, both soil gas sampling and soil matrix sampling may be warranted. Soil gas samples will assist in evaluating the risk associated with vapor intrusion, but these samples cannot be used to quantify the human health risk associated with other exposure pathways, such as dermal and ingestion exposure to soil. To evaluate these other exposure pathways, soil matrix sampling is necessary. Thus, if multiple exposure pathways exist at a site as indicated by the conceptual site model, soil gas and soil matrix sampling will be needed. Passive Soil Gas Passive soil gas sampling is a qualitative tool. Sampling devices, which house an adsorbent material, are placed in the subsurface and left to collect vapors over a time period of 10 to 15 days, dependent on site conditions. Organic vapors, migrating through the subsurface, encounter the sampling device and are passively amassed onto the adsorbent material. The sampling devices are then retrieved and analyzed. Passive soil gas sampling can be an effective tool in understanding the vapor intrusion pathway. The composition of subsurface soil gases can be determined from passive soil samples and the location of subsurface plumes can be mapped, particularly edges of plumes to determine if contamination is near existing or future buildings (see Step 4). Passive soil gas sampling methods can also collect soil gas from low-permeability and high- moisture settings, and are capable of detecting and reporting compounds present in very low concentrations. Likewise, passive soil gas samplers can be placed into potential preferential pathways for soil gas migration, such as utility corridors and foundation cracks, to determine if these pathways could affect indoor air quality. However, passive soil gas samples cannot quantify the contaminant concentration in soil gas or be used to determine the flux of contaminants over a given area. The concentration of VOCs on the adsorbent 1 The mention of trade names or commercial products in this Guidance Document is for illustrative purposes only, and does not constitute an endorsement or exclusive recommendation for use at DTSC sites. Equipment other than that listed may be used provided that the resulting performance meets the project data quality objectives. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 11 material in a passive soil gas sampler, though yielding a contaminant mass value, cannot be directly equated to soil gas concentration and the passive samplers should always be used with this understanding. Flux Chambers The flux chamber is a qualitative tool and should not be used for risk determination because of insufficient field validation of the flux chamber for use in the evaluation of vapor intrusion to indoor air. The emission isolation flux chamber yields a direct measurement of contaminant flux at a surface. VOC contamination, whether indoors or outdoors, can be located with flux chambers. Flux chambers can be used to determine if contamination is near existing or proposed future buildings by delineating plumes and plume edges (see Step 4). Likewise, flux chambers can be used indoors to determine if foundation cracks are entry points for contaminated soil gas into buildings. In evaluating vapor intrusion, flux chamber results represent an additional line of evidence for evaluating subsurface contamination. Appendix A contains additional information on flux chambers. Step 3: Is a Site a Candidate for Vapor Intrusion? To evaluate if a site is a candidate for vapor intrusion, two criteria are considered concerning the nature of the subsurface contaminants and the location of existing or proposed buildings relative to the location of subsurface contaminants. Criterion One: The chemicals in the subsurface must be volatile and toxic to present a vapor intrusion risk. The chemicals in Table 1 may be found at sites and are volatile and toxic enough to pose an indoor air risk. If a site contains any of the chemicals listed in Table 1, the site should be evaluated for vapor intrusion. The chemicals in Table 1 were taken from the USEPA Vapor Intrusion Guidance Document (USEPA, 2002a), with the addition of fuel oxygenates and two volatile polychlorinated biphenyl (PCB) congeners (monochlorobiphenyl and dichlorobiphenyl) (Davis et al., 2002; Davis and Wade, 2003). Soil gas, soil matrix, and groundwater should be tested for all the chemicals of concern at a site. Analytical detection limits should be sufficiently low to allow for evaluation of vapor intrusion. Hence, when determining if the vapor intrusion pathway is complete at a site based on the occurrence of the chemicals in Table 1, the analytical detection limits must appropriate (See Step 2 – Soil Gas). If the chemicals listed in Table 1 are not present at a site, vapor intrusion is not possible and no further consideration of this exposure pathway is needed. Criterion Two: The existing or future buildings at a site must be close to subsurface contamination so that vapor migration into indoor air is possible. For existing or future buildings not to be considered a candidate for vapor intrusion, the buildings must be greater than 100 feet away laterally from subsurface contamination (USEPA, 2002a). If buildings are not located near areas of concern, vapor intrusion is not possible and no further consideration of the exposure pathway should be needed. To determine if a building is 100 feet from a groundwater or soil gas contaminant plume, the horizontal distance from the edge of the building to the edge of the contaminant plume State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 12 should be measured. The lateral edge of the contaminant plume should be interpolated from the site characterization data with the edge of a plume defined by appropriate analytical detection limits. Evaluations of building distance from contaminant plumes should only be conducted if the movement of subsurface contamination has reached steady-state conditions. Meaning, these evaluations should only be conducted when the maximum migration potential of the subsurface plumes have been reached. For groundwater, the migration potential can be evaluated with data from routine sampling of groundwater monitoring wells. If the temporal contaminant trends from the monitoring wells indicate stable or decreasing contaminant trends, the maximum contaminant migration for groundwater has probably occurred. For soil gas, a similar evaluation can be conducted if routine sampling data is available from permanent or temporary sampling points. If there are no temporal soil gas data, the length of time to reach steady-state conditions must be estimated from the chemical release date. Knowing that soil gas moves by diffusion at a rate of approximately 25 feet per year (Hartman, 2004), the length of time needed for soil gas to travel from the chemical release point to the building in question can be estimated and compared to the date of the chemical release. If a sufficient amount of time has passed since the chemical release date to allow for diffusional movement to the building in question, then steady-state conditions have probably transpired. If contaminant plumes, whether in soil or groundwater, are increasing, 100 feet is not an appropriate distance between buildings and plumes for evaluating vapor intrusion. When evaluating the distances between subsurface contaminant plumes and buildings, it is important to consider whether preferential pathways exist which could allow vapors to migrate more than 100 feet laterally. These preferential pathways could be either natural or anthropogenic. Examples of preferential pathways include fractures, macropores, utility conduits, and subsurface drains (See Step 8 – Utility Corridor Assessment). Buildings with preferential pathways should be evaluated for vapor intrusion even if they are further than 100 feet from the contamination. Step 4: Evaluation of Acute Hazard in an Existing Building If a site is a candidate for vapor intrusion pursuant to Step 3, the site should be reviewed to determine if immediate action is necessary to verify or abate acute threats to human health. Indicators of acute threats are shown below, but other indicators may also exist. • Odors. Odors reported by building occupants may be an indication of vapor intrusion. The presence of odors does not necessarily correspond to adverse health effects or safety concerns, but it is prudent to investigate any reports of odors because many odor thresholds exceed their respective acceptable indoor air concentrations. • Physiological Effects. Exposure to vapors may cause headaches, nausea, eye and respiratory irritation, vomiting, and confusion. Sensitivity to these effects can vary greatly from one person to the next. Individuals most affected by vapors are children, the elderly, and people with pre-existing respiratory conditions such as asthma or bronchitis. These physiological effects may or may not be attributable to vapor intrusion but should be evaluated. In all cases involving physiological effects, the individuals should consult their physician. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 13 • Wet Basements. Buildings with basements over shallow groundwater are very prone to vapor intrusion. Basements with evidence of shallow groundwater, such as basements subject to frequent flooding, basements with wet walls during the rainy season, and basements built with moisture barriers, should be scrutinized closely for potential acute health threats. This is especially true for sites with significant subsurface contamination, such as the occurrence of non-aqueous phase liquid (NAPL) floating on the water table. • Fire and Explosive Conditions. The potential for fire and explosion from vapor intrusion should be evaluated. Fire and explosion concern is often raised with petroleum vapors. The lower explosive limit for gasoline vapor is 1.4 percent, or approximately 50,000 times higher than its corresponding odor threshold, thus making it an easily identifiable threat at petroleum release sites. Fire and explosion hazards related to chlorinated solvent vapor intrusion to indoor air are also easily identifiable. Very strong solvent odors would accompany flammable levels, which are approximately 1000 times higher than the odor threshold. Nonetheless, however unlikely an explosion or fire might be, it must be evaluated, particularly if the odors are strong within a building. Buildings with odors, occupants with physiological effects, and/or wet basements should be evaluated and the indoor air tested as soon as possible using procedures outlined in Step 8 of this guidance document. The results of the indoor air sampling should be evaluated pursuant to Step 9 and, if needed, the measures within Step 10 should be implemented to mitigate the vapor intrusion risk. DTSC recommends that the buildings with potential fire and explosive conditions be immediately evacuated and the local fire department be contacted. Re-occupancy of the buildings should only be granted with concurrence of the local fire department. After re- occupancy, Step 8, 9, and 10 should be followed as appropriate to evaluate vapor intrusion. For sites that have potential methane intrusion issues, DTSC’s guidance on methane should be consulted and followed as appropriate (DTSC, 2004a), in conjunction with this guidance document. Step 5: Preliminary Screening Evaluation If evaluation of a site pursuant to Steps 1 - 4 indicates a potential vapor intrusion problem, a preliminary evaluation of the site should be conducted using the attenuation factors provided by DTSC in this Guidance. In addition, the screening numbers for soil gas developed pursuant to SB 32 by OEHHA can be used as a mechanism to evaluate and prioritize sites subject to vapor intrusion (see below for additional information). Attenuation Factors for Preliminary Screening Evaluations To evaluate vapor intrusion with subsurface contaminant data, the attenuation factor (α ) for a given building must be determined. The attenuation factor represents the ratio between indoor air concentration and soil gas concentration, as follows: gas soil indoor C C =α where: State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 14 Cindoor = Indoor air concentration (ug/m3) Csoil gas = Soil gas concentration (ug/m3) DTSC recommends that the default attenuation factors in Table 2 be used along with the maximum detected soil gas concentration for preliminary screening evaluations. Default attenuation factors are provided for three foundation configurations; slab-on-grade, crawl space, and basement. The derivation of the default attenuation factors is provided in Appendix B. These default attenuation factors reflect reasonable worst-case conditions for California for the contamination of indoor air due to intrusion of vapors migrating from subsurface contamination. Hence, after lateral and vertical delineation of the subsurface contamination and determination of all the chemicals of concern at the site, a preliminary evaluation for vapor intrusion can be conducted with just the subsurface soil gas concentration data. Using the above equation, the indoor concentration of the chemicals at the site can be calculated. The associated cumulative health risk can be quantified using either the OEHHA indoor air screening numbers pursuant to SB 32 or the procedures described in Appendix C. The default attenuation factors assume the following conditions for their use in evaluating an existing or future building: • The subsurface is reasonably homogeneous (uniform). • No fractures exist in the subsurface. • Groundwater is greater than 10 feet below surface grade. • Fluctuations of the groundwater surface are minimal. • Non-aqueous phase liquid (NAPL) is not present on the water table. • Preferential pathways do not exist. • Biodegradation of vapors is not occurring. • Contaminants are homogeneously distributed. • Contaminant vapors enter a building primarily through cracks in the foundation and walls. • Building ventilation rates and the indoor-outdoor pressure differentials are constant. • Model assumptions are representative of site conditions. If the above conditions exist at a site and the evaluation of the subject building with default attenuation factors results in an acceptable cumulative human health risk, no further consideration is needed for this exposure pathway. However, if the above conditions do not exist when evaluating for vapor intrusion, the default attenuation factors should not be used. Instead, DTSC recommends proceeding to Step 6 and conducting a site-specific screening evaluation. Use of Soil Matrix Concentrations An attempt should always be made to collect soil gas samples rather than to automatically defer to soil matrix sampling. Nevertheless, when soil gas sampling fails at a site due to a shallow water table or the presence of clay-rich soil, the vapor intrusion risk may be evaluated using soil matrix sample data (see Step 2 – Soil Matrix). Soil matrix samples should be collected using the procedures in USEPA Method 5035A and the associated soil gas from the soil matrix data should be determined using the partitioning calculation procedures in Appendix E. Quantifying human health risk from Method 5035A soil matrix samples may yield results that are biased low due to inherent VOC escape during sample State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 15 collection (Hewitt, 1994; Hewitt, 1999; Liikala et al., 1996; Vitale et al., 1999). Under no circumstances should the risk associated with vapor intrusion be conducted with soil matrix samples collected by non-Method 5035A procedures. Use of Groundwater Concentrations While soil gas is the preferred data for the evaluation of the vapor intrusion, sites can be screened, in certain circumstances, with only groundwater contaminant data. In these limited cases, preliminary screening evaluations should be conducted using the default attenuation factors in Table 2. When performing preliminary vapor intrusion evaluations with groundwater data, the associated soil gas originating from contaminated groundwater must be determined, as follows: Csoil gas = Cgroundwater * Hc * Ct where: Csoil gas = Soil gas concentration (ug/m3) Cgroundwater = Groundwater concentration (ug/L) Hc = Henry’s law constant (unitless) Cf = Conversion factor (1000 L/m3) Screening for vapor intrusion with groundwater contaminant data should only be conducted for existing or future buildings that are far removed from the original source of the contaminant release. DTSC anticipates that the screening for vapor intrusion with groundwater contaminant data will only occur in the downgradient portions of lengthy chlorinated solvent plumes. When evaluating the downgradient portions of groundwater plumes for vapor intrusion, no vadose zone contamination should exist other than the VOC contamination due to groundwater degassing. Evaluations using groundwater data should only occur in portions of a groundwater plume where there is no evidence of non-aqueous phase liquid (NAPL) entrained within the water table aquifer. That is, VOC concentrations in groundwater for these evaluations should be less than one percent of their pure-phase solubility, which is an indicator of NAPL pursuant to Pankow and Cherry (1996). The groundwater data for these evaluations should meet the following requirements: • The groundwater monitoring wells are properly drilled, constructed and developed, and the wells are screened across the water table (see Step 2). • The well screen lengths within the water table are sufficiently short (<10 feet) to yield representative samples of the uppermost water-bearing zone. • The groundwater samples collected for analysis are representative of aquifer conditions. • The contaminant trends in individual groundwater monitoring wells are adequately established with an appropriate amount of sampling. • The analytical detection limits for the groundwater samples are at or below the Maximum Contaminant Levels (MCLs). • The density of the groundwater monitoring network is sufficient to accurately extrapolate groundwater isoconcentration contours throughout the area of interest. The intent of establishing contaminant trends within monitoring wells prior to screening groundwater for vapor intrusion is two-fold. First, the degree of natural temporal variability State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 16 of the VOC contamination must be established so that an appropriate contaminant input concentration can be used for modeling purposes. Second, the stability of the VOC plume must be demonstrated so that the risk to receptors would not be expected to increase due to contaminant migration. The evaluation of vapor intrusion should not be conducted with groundwater grab samples due to the inability to place the sampler at the top of the water table and the inability to establish temporal contaminant trends with such data. For sites with both vadose zone and groundwater contamination, the vapor intrusion risk associated with both contaminated media, soil gas and groundwater, should be provided to DTSC. The vapor intrusion risk associated with both contaminated media should be approximately the same and risk management decisions should be based on the higher of the two values. Additionally, if the risk from the respective contaminated media differ greatly, an explanation of this occurrence should be provided to DTSC. Use of Soil Gas Screening Numbers from the Office of Environmental Health Hazard Assessment Pursuant to Senate Bill 32 (SB 32), the California Land Environmental Restoration and Reuse Act, OEHHA published a list of screening numbers for specific contaminants. A screening number is defined in SB 32 as meaning the concentration of a contaminant published by an agency as an advisory number and the screening numbers are for the protection of public health and safety. The screening numbers required by SB 32 are not intended as mandatory cleanup standards for use by regulatory agencies that have authority to require remediation of contaminated soil. SB 32 states: A screening number is solely an advisory number, and has no regulatory effect, and is published solely as a reference value that may be used by citizen groups, community organizations, property owners, developers, and local government officials to estimate the degree of effort that may be necessary to remediate a contaminated property. A screening number may not be construed as, and may not serve as, a level that can be used to require an agency to determine that no further action is required or a substitute for the cleanup level that is required to be achieved for a contaminant on a contaminated property. The public agency with jurisdiction over the remediation of a contaminated site shall establish the cleanup level for a contaminant pursuant to the requirements and the procedures of the applicable laws and regulations that govern the remediation of that contaminated property and the cleanup level may be higher or lower than a published screening number. Numerous exposure pathways were evaluated in calculating the SB 32 screening numbers, including the vapor intrusion to indoor air exposure pathway. Hence, OEHHA developed soil gas screening numbers for vapor intrusion for many of the VOCs found in Table 1. The OEHHA screening numbers may be used to evaluate sites for vapor intrusion but only with an understanding of the assumptions and limitations used in the development of the screening numbers. We encourage interested parties to read and understand the OEHHA Advisory Document, along with its associated User’s Guide, before using the SB 32 screening numbers at a particular site. See the Cal-EPA website for the SB 32 Advisory Document and User’s Guide (www.calepa.ca.gov). The SB 32 soil gas screening numbers may be used to evaluate the vapor intrusion pathway for sites contaminated with VOCs. The SB 32 soil gas screening numbers are intended to be conservative and, under most circumstances, correspond to VOC concentrations that are State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 17 assumed to not pose a significant health risk to people who are subject to indoor vapor exposure. The presence of a chemical in soil gas at concentrations greater than the SB 32 screening number does not necessarily indicate that adverse human health effects are occurring. It simply indicates that a potential for adverse risk may exist and that additional evaluation may be warranted. The need for additional investigation and possible cleanup of affected areas may then proceed on a more site-specific basis. This step-wise approach can help expedite judgments about the degree of effort necessary to remediate contaminated properties and restore the properties to productive use. Also, the screening numbers can be used to assist in the prioritization of work. The SB 32 screening numbers should be used with an understanding of the assumptions and limitations presented in the OEHHA Advisory Document and its associated User’s Guide, as discussed below: • The SB 32 soil gas screening numbers for vapor intrusion only address a single exposure pathway. When evaluating the human and ecological risk associated with releases of hazardous substances to the environment, all potential exposure pathways should be evaluated. Mitigation of contaminant exposure must be conducted with an understanding of all exposure pathways, not just the vapor intrusion pathway. • The SB 32 screening numbers for vapor intrusion represent a concentration of a single VOC in soil gas for a carcinogenic risk of 1 x 10-6 and a hazard quotient of 1.0. Hence, for sites with a release of a single chemical into the environment, the screening numbers can be easily used to evaluate potential health effects. However, for sites with multiple contaminants, human health effects are cumulative and these cumulative health effects must be calculated. • A cumulative target risk level other than a carcinogenic risk of 1 x 10-6 and a hazard index of 1.0 may be appropriate for a site. • The use of the SB 32 screening number is entirely voluntary on the part of the responsible party and subject to the approval by the overseeing regulatory agency. At sites where cleanup of contaminated soils to meet the SB 32 levels would be very costly, the time and effort to develop more site-specific, and presumably less stringent, cleanup levels is usually warranted. • The SB 32 screening numbers for vapor intrusion should not be used to determine when impacts at a site should be reported to a regulatory agency. All releases of hazardous substances to the environment should be reported to the appropriate regulatory agency in accordance with governing regulations. Use of Occupational Safety and Health Administration (OSHA) Standards The OSHA Permissible Exposure Limits (PELs) are not an appropriate standard for evaluating the risk associated with vapor intrusion to indoor air in California pursuant to the California Health and Safety Code. Hence, for vapor intrusion sites, potential adverse effects to humans should be evaluated in terms of acceptable exposure based upon risk rather than upon comparison to OSHA PEL endpoints. One exception where OSHA PEL endpoints may be considered is for operating RCRA facilities pursuant to USEPA’s Environmental Indicators (EI) Program under the Government Performance and Results Act State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 18 of 1993. USEPA allows the use of OSHA PELs, as an interim measure, at operating RCRA sites to evaluate progress on correction action activities (USEPA, 2003a). Also, various operations at RCRA and non-RCRA sites are directly regulated by OSHA (e.g., spray booths, plating operations, etc.), and this Guidance does not apply to those specific operations. The use of OSHA PELs and USEPA’s Environmental Indicators Program is further discussed in Appendix F. At sites subject to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), cleanup levels are generally determined either by Applicable or Relevant and Appropriate Requirements (ARARs) or the risk assessment process. OSHA standards are not ARARs under CERCLA statute and regulations. Therefore, OSHA standards should not be applied to CERCLA cleanups. When a Preliminary Screening Evaluation Indicates an Unacceptable Risk These are the options for a site if the risk due to vapor intrusion is unacceptable by a preliminary screening evaluation: • Conduct an evaluation of vapor intrusion with appropriate site-specific data (Steps 6 and 7). • Collect indoor air samples to substantiate exposure from vapor intrusion as indicated by the preliminary evaluation (Steps 8 - 10). • Remediate the subsurface contaminants to acceptable levels as determined by the preliminary evaluation (Step 11). • Institute engineering controls to mitigate the exposure (Step 11). Step 6: Additional Site Characterization For a site that does pass a preliminary screening evaluation, a site-specific evaluation of vapor intrusion may be warranted. Additional site characterization may be needed to better delineate the soil gas concentrations at a building subject to potential vapor intrusion. Also, it may be prudent to measure the physical properties of the soil at a site to better understand the behavior of contaminant migration. For sites with existing buildings, one can sample the soil gas directly under the building foundation (sub-slab) or sample the air in the area of the raised foundation (crawl space). Each option is discussed separately below. Additional Soil Gas Sampling Where a building exists, ideally, soil gas samples should be taken under the building due to the potential for vapor accumulation under the foundation (Johnson and Deize-Abreu, 2003). In many cases, this will not be practical and, hence, the samples should be collected as close to the building as possible. At a minimum, soil gas samples should be collected at two locations, along opposite sides of the building. Large buildings should have more sampling points. The soil gas sampling should be started at 5 feet below surface grade and continue at 5 foot intervals, if possible, until the soil gas has been delineated vertically. For the collection of soil gas adjacent to offsite buildings, the execution of an agreement with the State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 19 offsite property owner for access may be warranted. A sample access agreement can be found in Appendix J. For future buildings, the soil gas sampling should occur on a 100 foot grid, or at a higher density so there is at least one soil gas sample associated with each potential building location. Hence, for future residential developments, the sampling grid might be fairly dense. The soil gas sampling should extend 100 feet beyond any potential building footprint pursuant to USEPA (2003a) (see Step 3, Criterion Two). Physical Characteristics of the Subsurface Soil samples can be collected for evaluation of the physical character of the subsurface. Soil cores, if taken, should be submitted to a geotechnical laboratory for site-specific determination of bulk density, grain density, total porosity, grain size, moisture content, and fraction organic carbon. The recommended methods for laboratory analysis are described in Appendix H. Enough samples should be taken so that the data can be statistically evaluated. The air permeability of the vadose zone should be determined from in-situ measurements rather than from laboratory measurements. In-situ measurements test a larger portion of the subsurface than a laboratory measurement. At the laboratory, core analysis for air permeability usually involves subjecting the soil core to a confining pressure which may bias the results low by potentially reducing the pore space within the soil core. In-situ measurements of air permeability should be conducted in the shallow vadose zone, the area of the vadose zone subject to advection by building-driven depressurization. The method for determining air permeability in the field during the collection of the soil gas samples is described in Appendix I. Additionally, information on the subsurface soil and engineered fill directly underneath the foundation of existing buildings should be obtained from the building’s geotechnical report. Reports usually contain geotechnical laboratory and engineering data for the native soil and fill material, along with fill thicknesses. The permeability of the subgrade material, rather than deeper soil, can control the rate at which vapors will be pulled through the foundation and into the building. Subslab Soil Gas Sampling (Existing Building) When contemplating the decision to conduct indoor air sampling, subslab soil gas sampling directly below the building foundation should also be considered. Subslab soil gas data, which is collected from the engineered fill directly under the foundation slab, indicate whether contaminants have accumulated directly under the building and which specific chemicals will degrade indoor air quality. Once subsurface vapors move directly under a building, the ability of the vapors to further attenuate is greatly reduced. The subslab air is within the advective envelope of the building-driven depressurization. The monitoring of the subslab soil gas is potentially less costly than monitoring indoor air quality. However, to evaluate the risk associated with subslab soil gas concentrations, the contaminant attenuation over the foundation slab must be known in order to determine the associated indoor air concentrations. If the attenuation factor associated with the building slab is unknown or cannot be determined, USEPA (2002a) recommends that an attenuation factor of 0.1 be used. However, empirical data shown at the 2004 Conference of the Association of Environmental Health and Science suggested that subslab attenuation factors may be closer to 0.01 (Dawson, 2004). Accordingly, an attenuation factor of 0.01 should be used State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 20 when evaluating subslab concentrations for vapor intrusion. When collecting subslab samples, the analytical detection limits should be appropriately low to effectively evaluate the indoor air risk. If proceeding directly to subslab sampling after preliminary screening, additional site characterization may not be necessary for the evaluation of vapor intrusion. That is, further characterization of the subsurface soil gas around the building, determination of the physical character of the vadose zone through geotechnical testing, and site-specific vapor intrusion modeling may not be needed. Hence, proceeding with subslab sampling, while intrusive to building occupants, may shorten the timeframe for evaluation of the exposure pathway and may help reduce the overall cost of a vapor intrusion evaluation. Methods and procedures for taking subslab samples are described in Appendix G. The collection of subslab samples can be invasive to building occupants, since it requires the removal of floor coverings and coring or drilling of the foundation slab. If chemicals are detected in subslab soil gas, installation of permanent sampling points may be necessary to determine the temporal variability of the data. It should be noted that the method employed to conduct subslab sampling creates a potential preferential pathway, and care should be taken to properly seal the sampling location upon installation. If subslab sampling is conducted, an appropriate number of samples should be taken to characterize the subslab area. At least two subslab samples should be taken, with one sample taken in the center of the building’s foundation. For large foundations greater than 5000 square feet, DTSC suggests that one subslab sample per 1000 square feet be collected. If indoor air sampling is subsequently needed, the indoor air samples should only be analyzed for the chemicals detected in the subslab soil gas. Sampling of Crawl Spaces (Existing Buildings) Air within a crawl space can be sampled as a substitute for subslab sampling or indoor air sampling. Crawl space air should be less affected by the lifestyle choices, such as household product use and smoking, of the building’s occupants than indoor air. Hence, the evaluation of the results of crawl space air sampling should be easier to interpret than indoor air sampling results. For evaluating the human health risk associated with crawl space air, an attenuation factor of 1.0 should be used for crawl spaces, which is consistent with USEPA guidance (2002a). Thus, the indoor air quality is assumed to be equal to the crawl space air quality for evaluation purposes. When conducted either subslab or crawl space sampling, appropriate public outreach should be conducted (see Public Outreach – below) Step 7: Site-Specific Screening Evaluations If evaluation of a site pursuant to Steps 1 - 6 indicates a potential vapor intrusion problem, a site-specific evaluation of the site may be conducted using appropriate fate and transport modeling. DTSC recommends that the USEPA version of the Johnson and Ettinger (J/E) (1991) model be used (USEPA Vapor Intrusion Model, USEPA, 2003). The USEPA Vapor Intrusion Model should be used to simulate site conditions using reasonable, site-specific input parameters. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 21 Use of USEPA Vapor Intrusion Model Spreadsheets The J/E model is a fate and transport model that calculates an attenuation factor (α; ratio of indoor air concentrations to subsurface soil gas concentrations). The model simulates the transport of soil vapors in the subsurface by both diffusion and advection into indoor air. Hence, by inputting the soil gas concentration, the model estimates the associated indoor air concentration. In September 1998, USEPA programmed the J/E model into Microsoft EXCEL™ and added a health risk component that calculates the risk from inhaling the specific chemical at the concentration estimated in indoor air. Individual spreadsheets were generated for different contaminated environmental media: soil gas, soil matrix, and groundwater. Version 3.0 of this spreadsheet model was released in 2003. Model results are provided as a risk-based soil, soil gas, or groundwater concentration protective of human health, or as an estimate of the incremental risk associated with user-defined initial contaminant concentrations. DTSC has modified the USEPA Vapor Intrusion Model spreadsheets by including California- specific toxicity factors and encourages the use of these spreadsheets for screening evaluations. The spreadsheets themselves can be downloaded from DTSC’s website. Information on human exposure factors is in Appendix C. There are DTSC-modified USEPA Vapor Intrusion Models for soil gas and groundwater. DTSC strongly encourages all users of these spreadsheets to review not only this Guidance but also USEPA’s User Guide for the spreadsheets before conducting any modeling for vapor intrusion at a site (USEPA, 2003b). Attenuation Factors for Site-Specific Evaluations In certain situations, the USEPA Vapor Intrusion Model can yield very low attenuation factors for shallow soil gas contamination, exceeding what is reasonable. DTSC does not anticipate that many sites will have attenuation factors of less than 0.00001 for shallow soil gas. Hence, when using the USEPA Vapor Intrusion Model in site-specific evaluations, particularly for brownfields redevelopment, the attenuation factors can in general be expected to range from 0.001 to 0.00001 depending on the future building design. The use of small attenuation factors, between 0.0001 and 0.00001, should be fully explained and justified. The basis for justifying small attenuation factors at a site should not rely entirely on the volumetric water content of the soil. This parameter can be highly transient, especially under buildings where rainwater can no longer infiltrate the soil. Existing Building Site-specific evaluations with the USEPA Vapor Intrusion Model should be conducted using the site data obtained in Step 6. A site-specific evaluation should only be conducted after lateral and vertical delineation of the soil gas contamination and identification of all the chemicals of concern at the site. Table 3 summarizes the input parameters for site-specific USEPA Vapor Intrusion Model evaluations for California and the default input parameters specific for California. Appendix D contains information on the limitations of the USEPA Vapor Intrusion Model and provides the rationale for the selection of default input parameters specific to California. Appendix D should be read before conducting fate and transport modeling with the USEPA Vapor Intrusion Model. If the size of the contaminant plume is smaller than the size of the existing building, a finite contaminant source can be assumed for modeling purposes. The procedures for the use of State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 22 a finite contaminant can be found in Johnson and Ettinger (1991) and USEPA (2003b). If using a finite contaminant source in the vapor intrusion modeling, the contaminant plume must be fully characterized both laterally and vertically. In the finite source model, both the soil gas concentration and the amount of contaminant mass in the subsurface are needed. Hence, the VOC contaminant plume must be characterized with both soil gas samples and soil matrix samples. The soil gas samples will yield the contaminant mass in the pore space of the soil and the soil matrix samples will yield the contaminant mass sorbed to the soil matrix, the mass partitioned into soil water, and mass of the free-phase contaminant liquid. Without sufficient characterization data, DTSC will not entertain the use of the finite contaminant source model to evaluate exposure due to vapor intrusion. Future Buildings Making a reasonable prediction for vapor intrusion into future buildings is difficult Many variables may alter subsurface vapor concentrations and the physical properties of the subsurface in the future, including but not limited to: 1) vapor concentrations in the subsurface may increase, accumulating directly under the foundation of a future building, 2) moisture content of the vadose zone directly under a building may decrease due to the inability of rainwater to infiltrate under the building, and 3) air permeability and moisture content of the subsurface may be altered due to construction activities associated with building construction, thereby altering the subsurface air permeability and significantly increasing the potential for vapor intrusion to indoor air. Additionally, there may be significant variability in the quality of foundation materials as well as the construction quality of future buildings. Some foundations will greatly exceed existing building standards and provide protection from subsurface soil gas intrusion. Other foundations will fail to halt soil gas intrusion. Environmental agencies do not regulate nor have any control over the quality of building materials and construction as a mechanism to alleviate vapor intrusion. Due to the above-mentioned uncertainties associated with predicting indoor air quality for future buildings, DTSC recommends that modeling approaches for future buildings be sufficiently conservative to protect public health. Accordingly, DTSC recommends that the input parameters in Table 3 be used for future buildings but with slight modification. To make a site-specific evaluation for future buildings, maximum soil gas and groundwater concentrations should be used. Also, an appropriate default value for the soil gas advection rate (Qsoil) for future buildings should be used. For small buildings (10 meters by meters), USEPA (2002a) recommends using a soil gas advection rate of 5 liters per minute. DTSC believes that this value is appropriate for California and should be used for future building scenarios. If the future building is larger than 10 meters by 10 meters, the soil gas advection rate should be proportionally increased as a function of building size. Hence, buildings larger than 100 square meters will have, for modeling purposes, soil gas advection rates greater than 5 liters per minute. If a site-specific screening evaluation indicates a potential risk to indoor receptors, either in existing buildings or in future buildings, the installation of permanent soil gas monitoring points should be considered. The installation of permanent monitoring points can be used to evaluate the long-term behavior of soil gas. In these cases, the temporal data trends would be compared to a concentration threshold that would indicate human health is being potentially impacted. When the concentration threshold is exceeded, indoor air testing would be warranted to evaluate the completeness of the exposure pathway. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 23 Step 8: Indoor Air Sampling Assessment Collecting indoor air samples to assess the risk from vapor intrusion is a challenge. An indoor air assessment requires more than just good data collection. Attention to detail with an acute understanding of the commonalities and differences between subsurface VOCs and other environmental factors, such as vehicle traffic, ambient pollution sources, and consumer products, is vital. Therefore, Step 8 includes information gathering tools and data collection techniques that focus the investigation on the relationship between the subsurface and the indoor air. Step 8 also outlines the proper use of ambient (outdoor air) samples and other air data to justify that the subsurface is not the contributor to indoor air degradation. Indoor air sampling is typically the last step in an vapor intrusion evaluation because of the complexity in evaluating the data. Interested parties need to think “outside the box” when collecting, reviewing and interpreting indoor air data. Typically, outside influences are not likely to impact the sampling results in soil gas and groundwater investigations. However, this is not the case for indoor air sampling where lifestyle choices, such as receptor smoking or the use of aerosol consumer products, can influence the sampling results. Furthermore, indoor air assessments are particularly difficult to evaluate when the predicted risk from vapor intrusion is low (less than 100-in-a-million cancer risk). These sites fall into the ‘grey area’ and will only be open to proper interpretation if the subsurface plumes are fully delineated, the conceptual site model is accurate, and buildings are adequately scrutinized prior to indoor air sampling. When contemplating indoor air sampling to evaluate vapor intrusion, an indoor air sampling workplan should be submitted to DTSC for review and approval. The following text discusses the items which should be included in the workplan. Site Visit Prior to preparation of an indoor air sampling workplan, a site visit should be conducted to confirm onsite building use and occupancy to further validate the CSM. If the subsurface investigation has identified residential or commercial buildings offsite as potential areas of concern, a neighborhood visit is important to ensure that all buildings are accounted for and documented on the site map. This information can be added to the CSM, specifying the location of the building, type of building construction, building occupancy use, and type of foundation. Also, the businesses in the surrounding area that could influence the indoor air sampling results should be noted. An aerial photograph of the site and the surrounding area is a good evaluation tool. The aerial photograph can also be used to display the results of the soil gas investigation and the lateral dimensions of the soil gas out to non-detectable concentrations. Detailed plot maps should be prepared from the information collected during the onsite and neighborhood tour and should be included in the indoor air sampling workplan. The plot maps should include all buildings, area streets, outdoor sample locations, monitoring well locations, soil gas sampling locations, utility corridors, predominant wind direction, and compass orientation. Another helpful piece of information is knowledge regarding other industries in the area that could have potential air releases, such as gasoline stations, factories, dry cleaners, parking lots, and freeways. Information on the types of industry in the neighborhood is used when selecting outdoor sample locations and interpreting the air data. The local air district should be contacted regarding the air permits issued in the surrounding neighborhood. The local air district can also provide data from their nearby State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 24 ambient monitoring stations. The ambient air data may be used in the uncertainty analysis, but the ambient data should be used with caution. Details that should be included with the ambient data are: date when the data was collected, the data collection method, the analytical detection limits, the meteorological conditions, and the exact location of the monitoring station in relationship to the site. Ambient air data that are reported as basin-wide results are not useful when evaluating vapor intrusion. The scope and purpose of the basin-wide data are beyond the scope and purpose of an indoor air study. However, ambient data from the local air district or the Air Resources Board are typically included in the final indoor air data report. When conducting a vapor intrusion investigation, ambient data are not used to subtract or reduce the potential impacts found in the indoor air. Any ambient data are included in the uncertainty analysis discussion of the final indoor air assessment report. The results of outdoor flux chamber sample analysis collected prior to indoor sampling may be included in the workplan. The flux chamber methods, sample duration, sample location, and detection limits should also be included in the workplan. Flux chamber data can be helpful when interpreting the results of the indoor air assessment and can be used in a qualitative matter in the uncertainty analysis discussion of the risk assessment. For example, an outdoor flux chamber measurement may determine that the open ground is off gassing VOCs. In the workplan, operating on-site soil vapor extraction (SVE) systems and/or groundwater extraction (GE) systems should be noted. Also, it should be noted if the facility is still in operation. Since air releases from the operation of an SVE or GE system or the ongoing operations of a facility can impact the outdoor air sample results, these potential outside influences may impact risk management decisions. Utility Corridor Assessment Utility corridors can act as contaminant migration pathways. Contaminants can migrate long distances within utility corridors, distances longer than predicted with conventional fate and transport models. Utility corridors with migrating contaminants may require immediate remedial action to stop further transport of vapors along this preferential pathway. This section summarizes the basic approach to assessing vapor migration in utility corridors. For more detailed information, see the State of Wisconsin’s Guidance Document (2003). All site investigations should include an evaluation of the utility corridors. If utility corridors are not present, the site evaluation should include this documentation. Facility records should be reviewed to determine if utility corridors are present,. Facility records include copies of the utility maps, historical use maps, building “as-built” diagrams, and building construction specifications. If soil gas and groundwater contamination extends offsite, an offsite utility corridor evaluation is warranted. Utility corridor maps from the appropriate municipalities should be collected and reviewed. If utility corridors are present, the site investigation should document the presence or absence of vapor migration within or along utility corridors by collecting active or passive soil gas samples along the corridors. In some instances where utility corridors are identified as significant pathways for vapor migration, monitoring of the corridors with permanently installed monitoring probes may be necessary. To document that a utility corridor is not a migration pathway for the site, it should be demonstrated that soil gas sampling yielded non- State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 25 detectable concentrations of VOCs. The indoor air assessment report should identify those circumstances where contaminant migration along or within utility corridors is of concern but cannot be investigated due to access problems. Utility corridors should be considered a potential preferential pathway for contaminant migration if any of the following conditions are met: • Utility corridors intersect contaminated media, including areas of non-aqueous phase liquid (free product). • Utility corridors provide a direct pathway from contamination to receptors in buildings. • Utility corridor backfill materials are more permeable than the surrounding native soil. Utility corridors at sites where the native soil is of lower permeability than backfill materials are of greater concern. If these conditions exist, vapors or free product can migrate within a utility corridor regardless of the depth to groundwater. Vapors could migrate in any direction, while free product may migrate in the downslope direction along a trench. Free product or vapor in a corridor could be carried to buildings that are serviced by or connected to the utility. Figure 3 is a decision tree flow diagram for evaluating utility corridors. If vapors are present in utility corridors, the extent of the contamination should be determined through soil gas sampling. Where contaminated soil gas in utility corridors impinge upon an existing building, an evaluation should be conducted to determine if the soil gas concentrations in the corridors are protective of human health. If utility corridor sampling is warranted, the corridor should be accurately located at the ground surface by an appropriate locator service. The backfilled material in the utility corridor should be sampled to obtain representative soil gas samples. To accomplish this and to avoid utility damage, the sampling locations should be hand-dug to verify placement of the sampling location within non-native material. Ground penetrating radar can be used to locate utility corridor backfill material. The soil vapor probe should be placed into the hand-dug hole and pushed carefully to an appropriate depth and then sampled pursuant to the procedures in Cal-EPA (2003). Indoor Air Samples To obtain an indoor air sample for estimating exposure, sampling locations, times and methodology should be carefully selected. A number of factors may directly influence the concentrations of chemicals in the indoor air. Contaminant concentrations are likely to fluctuate to some extent on a continuous basis, and sampling should be conducted with an understanding of this occurrence. Because of contaminant fluctuations in indoor air, the completion of the Building Survey Form (see Appendix K) will aid in interpreting the indoor air sampling results. To obtain an estimate of exposure, the indoor air sampling approach should involve multiple sampling events. It is generally recommended that sampling be conducted under conservative conditions during appropriate weather conditions with reasonable indoor air exchange. Indoor air samples are typically collected with all windows closed. If the sampling is occurring in the heat of the summer and the home is not air conditioned, the request to close the windows may not be appropriate. DTSC recommends the following when preparing the indoor air sampling workplan and collecting indoor air samples. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 26 1) Sampling Duration. Sampling events should be conducted to produce average concentrations of the monitored compounds over the anticipated daily exposure duration. For residential receptors, air samples should be collected over a 24-hour period. Air samples should be collected over 8 hours for commercial and industrial receptors and over a typical school day for students. Hence, the flow regulators on sampling canisters must be configured to capture an integrated air sample over the daily exposure duration. 2) Number of Sampling Events. One indoor air sampling event cannot be reasonably representative of continuous long-term exposure within a building. Multiple sampling events should be conducted to characterize exposure over the long term. Hence, numerous sampling events may be required within a building before DTSC would consider “no further action” for the exposure pathway. At a minimum, sampling data should be obtained over two seasons; late summer/early autumn and late winter/early spring. 3) Number of Sample Locations. The occupied living areas as well as basement areas should be sampled. Samples should be taken in a spatial gradient as identified through building screening. Samplers should be situated in the breathing zone, approximately 3 - 5 feet off the ground and lower if the receptors of concern are children as for a daycare center or school. Samples should be taken in the center of the room. At the very least, it is recommended that sampling points include the VOC infiltration point, which is typically the bathroom and kitchen, and the primary living area. For multi- storied residential buildings, at least one sample should be collected on each floor. When sampling an office building, samples should be taken in each discrete office location. Also, for office buildings, samples should be collected from a point of vapor entry, such as a sump or other enclosed space, to better define the potential route of entry and the maximum concentrations. 4) Sampling Equipment. When sampling indoor air, extra sampling canisters and flow regulators should be taken into the field in case the integrity of some of the canisters is compromised or if some flow regulators malfunction. To compute descriptive statistical estimates for most environmental data, a minimum of eight samples are generally necessary, depending on the coefficient of variation of the data and the underlying statistical distribution of the data. Given the cost of indoor air sampling, it is usually not cost-effective to collect enough samples to compute realistic statistical estimates. Usually, two to three samples are taken in a residence or one sample per office space. Therefore, indoor air risk analysis is nearly always based on a limited data set. In these cases, DTSC recommends that the maximum concentration of each identified chemical of potential concern be used to quantify the human health risks. Data Quality Objective Process The scope and objectives of the indoor air sampling should be established before the study is conducted. In planning an indoor air sampling assessment, the primary governing principle should be the RCRA Facility Investigation (RFI) or the CERCLA Remedial Investigation / Feasibility Study (RI/FS). The RFI and RI/FS site investigation and cleanup standards are a general performance standard rather than detailed procedural directives. These performance standards are referred to as the data quality objectives (DQO) process. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 27 The DQO process establishes the scope and objectives of the assessment before indoor air sampling is conducted. The DQOs are qualitative and quantitative statements that: • Clarify the indoor air study objective. • Identify the chemicals of concern (COCs). • Define the type, quantity, and quality of each piece of data collected in the study. • Define if the sample will provide qualitative or quantitative information. • Define how each sample will be used to assess if vapors are intruding into buildings. • Determine the most appropriate locations, sampling method, and sampling duration for data collection. • Specify the amount of acceptable uncertainty in the sampling results. • Specify how the data will be used to test the exposure hypothesis. Additional information on the DQO process can be found in USEPA (1994). Air Sampling Analytical Methods When sampling indoor air, the target compounds should be the same compounds identified in the soil gas and groundwater. The goal of indoor air sampling is to measure VOCs at levels low enough to compare to background indoor air levels. Therefore, the samples must be analyzed by methods that can achieve minimum detection limits of at least one part per billion by volume (ppbv) which is equivalent to 1 to 7 micrograms per cubic meter (µg/m3) depending on the molecular weight for each compound. The analytical methods for measuring VOCs in air that are capable of achieving these detection limits are TO-14A (non- polar compounds only) and TO-15 (polar and non-polar compounds). USEPA Method TO- 17 may also be used, if appropriate. Typically, USEPA Method TO-14A or TO-15 are used when conducting indoor air sampling. Depending on site conditions, TO-1 or TO-2 may be proposed, which are similar to OSHA sampling methods, but are rarely used for indoor air sampling. Prior to choosing an analytical method, the laboratory should verify that they can achieve the minimum detection limits of the target compounds. To avoid interference with background chemicals not found in the contaminated media of concern, the air analysis should be run using the selective ion mode (SIM). Using the SIM analysis technique will also ensure less bias in the results. In addition, a trip blank should be required to ensure that no cross contamination has occurred in the collection or transport of the samples. Very volatile compounds, such as vinyl chloride, can display peak broadening or co-elution with other species if the compounds are not delivered to the GC column in a small volume of carrier gas. If vinyl chloride is a chemical of concern, ensure that the laboratory undertakes sufficient effort to specifically quantify the chemical. Methods for collecting indoor air samples are described below. • USEPA Method TO-1. Method TO-1 uses Tenax adsorption in the field coupled with VOC analysis by GC/MS. TO-1 involves drawing air through a cartridge containing approximately 1 - 2 grams of Tenax resin. Selected VOCs are trapped on the resin, while other VOCs and most inorganic constituents pass through the cartridge. The cartridge is then transferred to the laboratory. For analysis, the cartridge is placed in a heated chamber and purged with an inert gas, which transfers the VOCs from the cartridge onto a cold trap and subsequently into the GC column. Component State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 28 identification is accomplished using a library search algorithm based on the GC retention time and mass spectrometry characteristics. Less sophisticated detectors, such as electron capture or flame-ionization, may be used for certain applications, but their suitability for a given application must be verified by the user. For sampling indoor air, only high resolution GC capillary columns should be used. • USEPA Method TO-2. TO-2 is similar to TO-1 except that a carbon molecular sieve (CMS) is used rather than Tenax resin. The use of a CMS allows for the capture and analysis of more VOCs than the Tenax resin. For example, vinyl chloride is not captured by Tenax resin but is captured by a CMS. Method TO-2 is suitable for evaluating certain non-polar VOCs that have a boiling point between -15 °C and 120 °C. The analytical detection limit varies with the analyte and detection limits of 0.01 to 1.0 ppbv are achievable with a 20-liter sample. • Method TO-14A. Air samples are collected in an evacuated stainless steel canister with subsequent analysis by GC. VOCs are concentrated in the laboratory with a cryogenic trap and then revolatilized, separated on a GC column, and passed to one or more detectors for identification and quantification, either by MS, electron capture, or flame- ionization. TO-14A is the best method for broad speciation of unknown trace VOCs in air. Nonetheless, care must be taken in using the sampling canisters, because some VOCs may be adsorbed or decompose through interaction with canister walls, and water may condense on the inside of the sampling canisters under high humidity conditions. • Method TO-15. TO-15 evaluates both polar and non-polar VOCs. GC/MS is used for identification and quantification of targets compounds as collected in an evacuated stainless steel canister. TO-15 establishes method performance criteria for acceptance of data, thus allowing the use of alternate but equivalent sampling and analytical equipment. TO-15 also uses a multisorbent/dry purge technique or equivalent for water management. There are only a couple of disadvantages for the method which include high analytical cost and the need for a highly skilled operator for the analysis. TO-14A and TO-15 samples are collected using canisters. The laboratory conducting the analysis will usually supply clean, certified canisters with the appropriate flow controller set for the specified sampling duration as a function of the anticipated daily exposure. Proper cleaning of canisters is important, since residual canister contamination can impact both detection limits and the reproducibility of results. Instructions for using the flow regulator should be obtained from the canister supplier or laboratory. In most cases, TO-14A or TO-15 will be used for indoor air sampling. The laboratory detection limit for Method TO-14A is 0.2 ppbv. Lower detection limits are possible with Method TO-15. Caution is needed when selecting the sampling method since high levels of VOCs in indoor air can overwhelm the GC/MS and damage the detector. If high concentrations of VOCs are anticipated, TO-14A should be used first, and if necessary, followed-up with TO-15 if lower detection limits are needed. For petroleum release sites, specific indicator compounds within petroleum should be evaluated for vapor intrusion exposure. Petroleum is a mixture of many individual compounds. Petroleum products, such as gasoline, diesel, fuel oil, and mineral spirits, have different chemical constituents and specific aromatic and aliphatic compounds. Analytical methods using a mass spectrometer detector allow for the identification of aromatic and State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 29 aliphatic hydrocarbons, polynuclear aromatic hydrocarbons, and oxygenated compounds such as ethanol, acetone and methyl tertiary butyl ether (MTBE). The discrete samples collected in most indoor air investigations may not adequately address temporal variation in the data. It is usually not possible to collect enough samples to do a rigorous statistical evaluation of long term average concentrations. As such, even using average concentrations collected in one or two days of sampling may not be reflective of long term average exposure levels used to evaluate health risks. For this guidance DTSC recommends that risks be estimated using maximum concentrations, or one-half the detection limit when a chemical of potential concern is expected to be present based on site characteristics, but which may not have been detected due to elevated detection limits for some types of air sample analyses. Contingency Planning Indoor air sampling data will be used to identify further activities or responses to better ascertain human health impacts and their associated mitigation measures. The need for specific responses will be determined on a case-by-case basis, depending on the data from the two indoor air sampling events. Hence, for the indoor air sampling workplan, a contingency plan is prepared prior to initiating indoor air sampling and included as part of the sampling plan. The following is a general outline of responses subsequent to collecting and evaluating indoor air sampling data; however, there is a range of potential responses that can be considered. Indoor Air Sampling Results (minimum of two indoor air sampling events needed) Response Activities Risk: <10-6 HI: <1.0 Minimal Determine that the soil vapor plume is stable. Risk: 10-4 to 10-6 HI: 1.0 to 3.0 Monitoring Install permanent subslab monitoring points and/or permanent vadose zone monitoring points and collect soil gas samples and indoor air samples semi-annually. Risk: >10-4 HI: >3.0 Mitigation Institute engineering controls to mitigate exposure and collect soil gas samples and indoor air samples semi- annually to verify mitigation of exposure. HI = hazard index – sum of hazard quotients of specific chemicals found in indoor air The above table is provided as guidance and is not meant to circumvent the Superfund regulatory process of the nine feasibility study criteria pursuant to Title 40, Federal Code of Regulations, Section 300.430. All response actions associated with indoor air sampling should be done in consultation with DTSC or the lead regulatory agency. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 30 Indoor Air Sampling Workplan The indoor air sampling workplan, which should be submitted to DTSC for review and approval, should include the following: • History of the site. • Results of site visit (inventory of onsite and offsite buildings). • Conceptual site model. • Utility corridor assessment. • Number and type of air sample collection. • Duration of the air sample collection. • Laboratory analytical methods. • Contingency plan. After approval of the indoor air sampling workplan by DTSC, the occupants of the buildings potentially subject to vapor intrusion are contacted and indoor air sampling takes place. Step 9: Indoor Air Sampling Indoor air sampling may require four visits to the building subject to vapor intrusion. The first visit is the pre-sampling interview with the occupants, the second and third visits are during the placement and retrieval of the air sampling equipment, and the fourth visit is to discuss the results of the indoor air sampling with the building occupants. A representative of DTSC should be present during all visits, and sampling technicians are advised to conduct indoor air sampling in pairs. DTSC’s public participation unit can assist with planning and conducting sampling visits. Prior to the pre-sampling interview, an initial contact with the building occupants through telephone interviews is conducted. Residents should be contacted approximately 30 days prior to the indoor air sampling event. The purpose of the phone contact is to provide an overview of the history of the project, the intent of the indoor air assessment, and to invite the occupants to participate in the investigation. Voluntary participation and an individual’s right to privacy are very important when conducting indoor air sampling. To ensure that the privacy of each building occupant is protected, all indoor air sampling information is kept confidential. The confidentiality of the data should be communicated to the building occupant at the time of the phone interview. Appointments are scheduled at the convenience of the building occupant. Therefore, it is not uncommon to schedule appointments and sampling in the evening after people return home from work. A pre-sampling interview should be conducted for each building. During this site visit, the Building Survey Form should be completed (see Appendix K) and a screening of the building should be conducted. A floor diagram should be generated, illustrating the floor layout, chemical storage areas, garages, doorways, stairways, basement sumps, plumbing, electrical conduits, elevator shafts, and any other pertinent information (New York, 2001). Compass direction should be included on the floor diagram. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 31 Upon deployment of the sampling equipment on the second site visit, the Building Survey Form is updated to include the location of the sampling equipment, time, date, identification number, and environmental conditions. At this time, it is important to ensure that no changes to the condition of the building have taken place since the first visit and that no consumer products are left open. A photograph of each sampler should be taken with the identification tag and pressure gauge visible. A second photograph and notes are taken when the sampling equipment is collected. Any changes in the environment should be noted and the occupant(s) asked if any consumer products were used or if there were any activities (such as smoking) that may have taken place during the time the sampling equipment was in the building. The laboratory reports for the indoor air sampling should be communicated to the building occupants. The results should be initially communicated verbally over the telephone to the occupants with another site visit shortly thereafter to explain the results directly. The final written report associated with indoor air assessment should be made available to all building occupants. If needed, a public workshop or forum should be convened to communicate the testing results to the community along with the associated mitigation measures. DTSC recommends that public meetings be held after each indoor sampling event. Ideas and suggestions for holding public workshops or forums are provided in the Public Participation Section. Building Screening for Preferential Pathways A preferential pathway is a crack or opening in the building foundation which may allow for the flow of subsurface vapors into the indoor air space. An opening in the building foundation can be located at the foundation-wall joints, around where plumbing, electrical, or sewer lines enter the building from the subsurface, at elevator shafts, floor drains, or around bathtubs and showers. Likewise, vapors may enter a building through foundation cracks and along concrete control joints in the foundation. Vapors migrate from the subsurface due to changes in pressure with the building. The rate at which air enters a building is a function of several factors including wind speed, indoor- outdoor temperature differences, barometric pressure changes, height of the building, leaks in the building shell, and ventilation equipment such as bathroom and kitchen fans, furnaces and fireplaces. Although these pressure differences are small, typically between 1 and 10 pascals, this slight depressurization can cause the migration of soil gases through cracks and openings in the building’s foundation to indoor air spaces (USEPA, 1992a, 1992b). Figure 2 shows conceptually how subsurface vapors migrate into buildings. During the pre-sampling interview, an evaluation of the preferential flow pathways and the ventilation system should be conducted. Problems with the building ventilation system may in some cases exacerbate what would otherwise be relatively minor vapor intrusion concern. VOC readings from the preferential pathways should be recorded using an appropriate field instrument. Selection of the field instrument should be based on the anticipated VOC concentrations entering into the buildings. If contaminants in soil gas or subslab samples were found at high concentrations, then field measurements can be conducted with a photo- ionizing detector (PID) or a flame-ionizing detector (FID), since the anticipated indoor air concentrations would exceed the analytical detection limits of these instruments, which is approximately one part per million by volume. If the anticipated indoor air concentrations are low, then a field portable gas chromatography/mass spectrometry (GC/MS) instrument may be used to evaluate the preferential pathways. This instrument requires a trained State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 32 operator but provides instantaneous indoor air results. The standard operating procedures (SOP) for the instrument should be included, along with its detection limits, in the indoor air sampling workplan. The field GC/MS may be run in MS mode to gather qualitative information about the suspected chemicals of concern. Unlike a PID or FID, the field GC/MS in MS mode can qualitatively identify the presence of a specific chemical. For a quantitative evaluation, the field portable GC/MS must be run in GC/MS mode. To shorten the run time and ensure that the instrument detects only those chemicals known to be in the subsurface, the GC/MS should be run in the selective ion mode. All measurements collected with the portable field equipment should be recorded, annotated on building plot plans, and included in indoor assessment reports. Building Screening for Consumer Products Field instruments can be used to evaluate contaminant sources that might degrade indoor air quality unrelated to vapor intrusion, such as chemicals in common consumer products, which might bias indoor air sample collection. During the pre-sampling site visit, these sources can be identified and either sealed or removed prior to indoor air sampling. It is important to identify and mitigate the consumer products as contaminant sources prior to collecting indoor air samples with Summa™ canisters, so the analytical results can be interpreted without this confounding factor. Removing these interfering sources from the indoor environment prior to testing is the most effective means of reducing such interference. Sealing containers may be acceptable, but the containers should be tested with a field instrument to demonstrate that the seal is tight. The inability to eliminate potentially interfering substances may be justification for not sampling. Once these interfering conditions are corrected, ventilation may be needed before sampling to eliminate residual contamination (New York, 2001). Commercial and household products in buildings should be inventoried every time air is tested to provide an accurate assessment of their potential contribution to indoor air VOCs. Each room in the building should be inspected, and products that contain VOCs should be listed on the Household Products Inventory Form (Appendix L) along with the field instrument readings obtained near the containers. The volatile ingredients should be recorded for each product. If the ingredients are not listed on the label, the manufacturer’s name, address, and phone number, if available, should be recorded. It is not uncommon for indoor air sampling to show trace levels of these VOCs. Since the recommended TO-14A and TO-15 sampling methods can achieve detection limits down to 0.01 micrograms per liter, off-gassing of normal household items, such as household cleaners, glues, fingernail polish remover, aerosol sprays, carpeting, paint, recently dry-cleaned clothes, and tap water can interfere with the results. Indoor Air Sampling Indoor air sampling should be done in an environment that is representative of normal building use. Heating and air conditioning systems should be operated normally for the season and time of day. Weekend sampling, when buildings are shut and not occupied, is not recommended and may bias the results low, since the heating and air conditioning systems may depressurize the building relative to the subsurface. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 33 Any ventilation should be conducted twenty-four hours or more prior to the scheduled sampling time. If ventilation is necessary, windows and doors should be opened for at least 10 to 15 minutes. During colder months, heating systems should be operating for at least twenty-four hours prior to the scheduled sampling time to maintain normal indoor temperatures above 65 °F before and during sampling. The following should be recorded 24 hours prior to sampling: • Any open windows, fireplace dampers, openings or vents (this may be difficult in office or school environments). • The operation of ventilation fans. • Smoke (note distance to outdoor smoking area from building entrance). • Type of kitchen stove/oven (gas or electric). • Fresh paint. • Use of wood stove, fireplace or other auxiliary heating equipment, (e.g. kerosene heaters). • Operation or storage of cars in attached garage; for offices/businesses, the distance from the entrance to parking lot or street. The following should not be permitted during the sampling event: • Allowing containers of gasoline or oil within the building or garage area, except for fuel oil tanks. • Cleaning, waxing or polishing of furniture or floors (if cleaning is needed, use water only). • Using air fresheners or odor eliminators. • Using materials containing VOCs (dry markers, white out, glues, etc.). • Using cosmetics including hairspray, nail polish, nail polish removers, perfume, and cologne. • Applying pesticides. Ambient (Outdoor) Air Samples When an indoor air assessment is conducted, ambient air data (outdoor samples) should also be collected. Since the focus of the indoor air assessment is on collecting data specific to the soil or groundwater contamination, the ambient air sample should be evaluated in the same manner. The ambient air data can be used as a qualitative tool to provide information on outside influences on indoor air quality. In addition, ambient air samples provide quality control information about the collection and analysis techniques used. Ambient air sampling may help determine whether the laboratory is able to detect low ambient levels of target VOCs or whether sample contamination or other problems have contributed to unusual results. For measuring ambient air, DTSC recommends that ambient sampling begin at least one hour, and preferably two hours, before the indoor air sampling begins. This is recommended since most buildings have an air exchange rate of 0.5 - 1.0 exchanges per hour and, thus, ambient air enters the building before indoor air sampling begins. The ambient air sample should be collected until at least 30 minutes prior to the end of the indoor sampling period. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 34 The ambient air sample should be in an upwind location on the upwind side of the building. The sampling equipment should be located away from gasoline stations, automobiles, gasoline-powered engines, oil storage tanks, industrial facilities, or dry cleaners. The sampler should not be hung on vegetation but be placed away from wind breaks, such as trees or bushes. The sampling equipment should be at least five feet off the ground, at the approximate midpoint of the ground story level of the building, and about 5 to 15 feet away from the building. The focus of the indoor air sampling evaluation should be on the specific chemicals identified in the soil gas or groundwater. The justification for this focus is: • Control strategies are designed to prevent subsurface contaminants from entering the building. Chemicals present in the building that are not known to be in the subsurface, but are risk drivers, will not be reduced when remedial controls are implemented. • The objective of the indoor air sampling investigation is to determine if the contamination underneath the building is entering the indoor environment. • Background (ambient) samples should only be used to determine if the same chemicals of concern are also present in ambient air and could be contributing to the concentrations indoors. • If the chemicals of concern in indoor air are also present in ambient air, the outdoor data is qualitative. • If outdoor or indoor samples comes back from the laboratory with all non-detectable concentrations, the data should be rejected and the samples should be reanalyzed. Ambient air in California contains numerous VOCs, and these VOCs, such as benzene and tetrachloroethylene, should be found in both outdoor and indoor air, regardless of the occurrence of vapor intrusion. However, vinyl chloride and daughter products from the breakdown of chlorinated solvents, such as 1,1- dichloroethylene and cis-1,2-dichloroetheylene, are NOT typically found in ambient air. Under no circumstances should indoor air samples be collected in a building not subject to vapor intrusion as a way to evaluate background concentrations. Indoor air concentrations can vary greatly between buildings even if each building is used for similar purposes. DTSC believes that using a building as a “control” is unreliable. Quality Assurance/Quality Control Only certified clean sampling devices should be used for air sampling. Precautions should be taken to avoid sample interference such as fueling vehicles prior to sampling or using permanent marking pens in the field. A trip blank is required to ensure that there are no impacts from these types of sources that could affect the results of the study. Once the samples are collected, they should be stored according to the method protocol and delivered to the analytical laboratory as soon as possible. Samples should not exceed recommended holding times prior to being processed by the laboratory. Field blanks should be submitted and analyzed with the samples to provide a quality check. Laboratory procedures for sample accession and chain-of-custody should be followed. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 35 Step 10: Evaluation of Indoor Air Sampling Results DTSC recommends a minimum of two indoor air sampling events before making a final risk determination for a site. One sampling event should occur in the late summer/early fall and another during late winter/early spring. The maximum measured indoor air concentration of a specific chemical should be entered into the equations given in Appendix C of this guidance in order to calculate the risk or hazard posed by that chemical for vapor intrusion. Alternatively, the indoor air concentrations can be compared to the OEHHA target indoor air concentrations. The risks from all target VOCs should be added together to obtain the total risk for the indoor air exposure pathway. Any site-specific exposure evaluation that deviates from the assumption of residential land use should be performed only with the approval of the DTSC. DTSC stresses that the inhalation of indoor air contaminated with VOCs intruding from the subsurface is only one of many exposure pathways that are evaluated in a human health risk assessment. Hence, the risk or hazard from this pathway is added to the risks/hazards posed by all other chemicals and all other potentially complete exposure pathways, in order to calculate the total or cumulative risk at a site, as discussed in other USEPA guidance (USEPA, 1989). The background or ambient sample results should be included and discussed in the uncertainty analysis section when reporting sampling results. Response Action and Contingency Planning Indoor air sampling data should be used to identify further activities or responses to better ascertain human health impacts and their associated mitigation measures. The need for specific responses will be determined on a case-by-case basis, depending on the data from the two indoor air sampling events. The response action for the site should follow the contingency plan as provided and approved by DTSC in the indoor air sampling workplan. All response actions associated with indoor air sampling should be done in consultation with DTSC or the lead regulatory agency. Step 11: Mitigate Indoor Air Exposure, Monitoring, and Implementation of Engineering Controls DTSC considers four remedies to be common for the mitigation of vapor intrusion. Three criteria were used to select the recommended mitigation measures: effectiveness, implementability, and cost. Other remedies may be proposed for DTSC review and approval. These remedies may be used to mitigate vapor intrusion but additional measures may be warranted, such as soil gas monitoring, subsurface vapor extraction, sensors, alarms, conduit seals, slab crack sealing, utility trench dams, and enhanced ventilation systems. While specific remedies are not discussed here for sites where vapor intrusion yields low indoor air VOC concentrations, a combination of enhanced interior ventilation systems, conduit seals, utility trench dams, and other easily installed improvements should be considered for these types of scenarios. All design, construction, operation, and maintenance activities associated with vapor intrusion remedies should be conducted and supervised by a California Registered Civil Engineer with DTSC oversight and inspection. When implementing these remedies, one State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 36 must follow the California Energy Code (Title 24) for weatherization, which could result in additional energy savings and lower utility bills, as well as reduced VOC concentrations inside a building. Mitigation Measures The four remedies are discussed below. I. Excavation of VOC Sources The excavation and disposal of VOC contaminated media is a viable remedy to mitigate vapor intrusion. Excavation can be a permanent solution for alleviating threats to human health and the environment. All excavations should be backfilled with clean fill material pursuant to DTSC (2001a). The presence of additional sources and the onsite migration of VOCs from offsite sources should be considered when contemplating this alternative. Soil excavation at a site should be considered only when VOC contamination is shallow, usually less than 15 feet below grade, does not extend under buildings, and when the contamination is limited in extent, usually less than 500 cubic yards in volume. For larger contaminated areas, other remedial methods besides excavation, such as soil vapor extraction and in-situ chemical oxidation, may reduce the VOC contamination to levels protective of indoor air quality. If a consent order or an Operation and Maintenance (O&M) agreement is developed for the excavation, typical activities that may be required include: 1) Collection of confirmation soil samples in the excavation pit to verify removal of all contaminated material. 2) Sweeps of the ground surface with a field instrument to monitor for the occurrence of VOCs. 3) Installation and routine monitoring of soil gas probes in the excavation area to verify mitigation of the soil gas plume. II. Existing Building Retrofit - VOC Collection and Passive Vent Systems (Without Membrane) The installation of a subslab soil gas venting system can mitigate vapor intrusion into existing buildings. This mitigative approach involves the installation of a subslab collection system with either a passive or active venting system in existing structures where installation of a membrane system below the foundation is not feasible. These types of systems have been used in the past to mitigate the intrusion of radon into buildings. The following items should be considered when designing a subslab venting system: 1) Collection Pipe Spacing. A collection pipe system for VOC capture should be installed immediately beneath or adjacent to the foundation slab. The number and spacing of collection points should be based upon the soil and engineered fill properties underneath the building. The diameter of the piping should be appropriate for the capacity of the collection system. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 37 2) Collection Pipe Layout. The gas collection piping should be installed either horizontally or vertically beneath the building. Horizontal collection piping is usually installed along the perimeter of the building with horizontal drilling techniques, with the piping physically extending under the building. Vertical collection piping is installed within the interior of the building with vertical drilling techniques. Care should be taken on installation of the collection system so that building footings and utility corridors are avoided. The collection pipe system should be connected using threads, rather than connected with glues or solvents. The need for drainage or de-watering improvements to prevent flooding of any portion of the collection piping should be evaluated and suitable improvements should be contemplated, as necessary, to insure the proper operation of the collection pipe system. 3) Vent Riser Design. The underground gas collection pipes should be connected to solid vent risers that extend above the building. The vent risers should be equipped with a sampling port and fitted with a non-restricting rainguard to prevent precipitation and debris from entering the piping system. Vent risers should be properly secured to the building for protection against damage. Vent risers should terminate at a minimum of two feet above the roof of the structure and be a minimum of 10 feet away from any window or air intake into the building. The diameter of the vent riser should be appropriate for the capacity of the system. A small fan or blower within the vent riser may be required. If a fan or blower is warranted for the system, the installation of a utility trench to the riser may be necessary for the connection to electrical power. 4) Utility Conduit Seals. Conduit seals should be provided at the termination of all utility conduits to reduce the potential for gas migration along the conduit to the interior of the building. These seals should be constructed of closed cell polyurethane foam, or other inert gas-impermeable material, extending a minimum of six conduit diameters or six inches, whichever is greater, into the conduit. Wye seals should not be used for main electrical feed lines. 5) Air Discharge Permits. Permits or authorizations from the local air pollution control district (APCD) or air quality management district (AQMD) may be required for venting systems that exhaust to atmosphere. DTSC recommends that the local APCD or AQMD be consulted to confirm their requirements. III. Future Building Construction - VOC Collection, Membrane, and Passive Vent Systems This remedy for new buildings involves the installation of a passive subslab VOC collection and vent piping, and a membrane system underneath the foundation. All considerations for the existing structure retrofit remedy described above are applicable for this mitigation measure, except for the following: 1) If an appropriate permeable engineered material is needed for the collection piping (e.g., sand or gravel), the evaluation of native soil characteristics may not be necessary for the pipe spacing design. 2) Gas Barrier/Membrane System should meet the following requirements: a. Gas membranes should be constructed of appropriate materials and thicknesses. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 38 b. Gas membranes should be placed a maximum of one foot below the foundation slab and a maximum of six inches above the gas collection piping. c. Protective layers consisting of at least two inches or more of sand and/or geotextile (six ounces per square yard at a minimum) should be laid below and above the membrane. d. Without an engineering evaluation and confirmation data to support the beneath footing passage, the membrane should not pass below footings and/or stiffener beams of the structure due to seismic concerns. e. Gas tight seals (e.g., boots) should be provided at all pipe or conduit penetrations through the membrane. Gas tight seals should be provided where the membrane attaches to interior and perimeter footings. f. A smoke test of the membrane system (as recommended by the membrane manufacturer) should be conducted to ensure no leaks exist. Where leaks are identified, appropriate repairs should be undertaken and smoke testing should be repeated until no leaks are detected. IV. Future Building Construction - VOC Collection, Membrane, and Active Vent Systems In some situations, newly constructed buildings will require active subsurface venting to alleviate vapor intrusion. In this remedy, all considerations for the existing structure retrofit remedy specified above are applicable; however, a properly sized blower will need to be included in the design. An air permit from the local APCD or AQMD is typically required for an active venting system, and it is advisable to consult with the APCD or AQMD for permit requirements. The additional considerations for an actively vented building are: 1) Active Injection of Air Under Buildings. Active injection of air under a building to enhance venting is not recommended without an engineering design. The air injection system may force vapors into a building by creating elevated subsurface pressures or force vapors into unprotected neighboring structures. Although an air permit from the local APCD or AQMD is typically not required for an active injection of air system, it is advisable to consult with the APCD or AQMD. 2) Lower Explosive Limit of Chemicals. For sites where subsurface concentrations are above the lower explosive limit (LEL) of any constituent and a subsurface gas pressure of one psi or more is present, the site should be carefully evaluated and a deep well pressure relief system or other improvements, which reduce or eliminate subsurface gas levels and pressures, should be considered in addition to the building protection system. Mitigation of the elevated gas pressures at these sites may be required as a condition of site approval. The selection of the style of venting, either active or passive, is based on the level of mitigation needed to prevent vapor intrusion. The need to actively vent a building should State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 39 consider the level of protection needed, the type of receptor being exposed (residential, commercial or industrial), and the duration of the potential exposure. If there is uncertainty that passive venting of a building will satisfactorily protect receptors, active venting should be undertaken. Operation and Monitoring (O&M) Requirements for Venting Systems Typical O&M activities for the mitigation of vapor intrusion by either passive or active venting systems may include the following: 1. A one-time initial indoor air testing of all newly vented buildings to determine if the mitigative remedies are functional and operating according to design specifications. 2. Routine inspection of the area of concern, including all visible components of the VOC venting systems and the multi-level gas probes, to ensure there are no significant changes in site condition and there are no signs of degradation of the VOC remedy components. 3. Routine monitoring of air, lowest accessible floor and enclosed areas of the structures of concern, and grade surface areas, to ensure there are no potentially significant changes in subsurface gas concentrations. 4. Routine monitoring of vent risers for flow rates and gas concentrations to confirm that the VOC venting systems are functioning properly. 5. Routine maintenance, calibration, and testing of functioning components of the VOC venting systems in accordance with the manufacturers’ specifications. Permanent Soil Gas Monitoring Points The installation of permanent soil gas monitoring points should be considered when the subsurface soil gas concentrations approach values that are not protective of human health. The installation of permanent monitoring points can be used to evaluate the long-term behavior of soil gas adjacent to existing or future buildings. In these cases, the temporal data trends would be compared to a concentration threshold that would indicate human health is being potentially impacted. When the concentration threshold is exceeded, indoor air testing would be warranted to evaluate the completeness of the exposure pathway. When a soil gas monitoring program is proposed, a detailed outline for the program should be prepared and submitted to DTSC for review and approval. The outline should specify monitoring procedures, locations, frequencies, and equipment. A contingency plan should also be provided along with a description of the conditions at which the contingency plan would be implemented. The design of the VOC monitoring program should incorporate the following considerations: 1) Monitoring by subsurface gas probes should include the measurement of the concentrations of VOC by TO-14A, methane, oxygen, and carbon dioxide as well as the measurement of the gas pressure within the probe and the barometric pressure at the time of the monitoring. For oil field sites, landfills, or other sites where the presence of hydrogen sulfide is suspected, analysis of hydrogen sulfide should also be included. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 40 2) Periodic monitoring of combustible gas levels along the ground surface in open areas, within crawl spaces beneath a structure, and in indoor air may also be included as part of this program. 3) All gas probes should be properly secured, capped and completed to prevent infiltration of water and ambient air into the subsurface and to prevent accidental damage or vandalism of the probes. Replacement or repair may be needed due to the conditions of the gas probes or disturbance due to construction activities. For probe surface completions, the following components should be installed: a. Surface seal. b. Utility vault or meter box with ventilation holes and lock. c. Gas-tight valve or fitting for capping the sampling tube. 4) Changes in subsurface conditions may warrant the re-evaluation of the soil gas conditions at the site. Sites that potentially have VOC soil gas contamination associated with the biodegradation of organic material entrained within the soil may require reassessment of soil and soil gas conditions after completion of the grading activities for construction purposes. This is because the distribution of the organic material, oxygen and soil moisture may be altered by the grading activities. The placement of fill containing elevated levels of organic matter can result in higher post- grading VOC concentration levels. 5) Surface paving and building construction can alter the movement of VOCs in the subsurface. For buildings subject to vapor intrusion, nearby construction activities can affect the potential for vapor intrusion. Oftentimes the building becomes the easiest vent point because trenches and pipes installed below the building provide a relief point. Therefore, the installation of hard-scraped areas covering 5,000 square feet or more within fifteen feet of any structure of concern may require the installation of VOC mitigation measures such as vent trenches and vent piping, in addition to a soil gas monitoring program, to protect the structure. Perimeter Monitoring at a Facility The installation and routine monitoring of perimeter soil gas probes may be required to evaluate the potential for VOC migration during the venting of buildings. The perimeter soil gas monitoring system should include a network of multi-level soil gas monitoring probes, evenly spaced at approximately 1,000 feet apart, with a minimum of four locations, along the perimeter of the site, between the property boundary and the membrane system. The multi- level sampling probes should be installed approximately 5 and 15 feet below grade depending upon the site geology, depth of fill material, and depth of groundwater. Institutional Controls and Deed Restrictions When the removal of all volatile chemicals from the subsurface is not possible, institutional controls with their prescribed notifications, prohibitions, and engineering controls must be utilized to prevent exposure due to vapor intrusion. If existing conditions may cause unacceptable future risk to receptors, effective legal notification to future buyers of the property, occupants of future developments, or re-developments on the property will be required. In this case, it is appropriate to record in the property deed for the site: 1) a notice of the existing conditions known to the environmental agency that may cause potential State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 41 unacceptable risk from vapor intrusion or other exposure pathways, 2) a prohibition against construction without approved removal or treatment of contamination to approved risk-based levels, and 3) the implementation and monitoring of appropriate engineered remedies to prevent indoor air contamination until specific risk-based environmental cleanup levels have been met. This documentation should clearly name the regulatory agency responsible for the oversight and enforcement of the institutional controls. Deed restrictions should be approved by DTSC legal counsel and publicly recorded in the County Recorders Office. DTSC has approved standard Model Deed Restrictions that will reduce the work burden for all parties involved in this effort. Additionally, deed restrictions or land use covenants must include the requirement to notify utility workers or contractors that during utility installation or construction activities, these workers may contact contaminated soil and ground water. BIODEGRADATION OF VOLATILE PETROLEUM HYDROCARBONS Aerobic biodegradation of petroleum hydrocarbons will occur in the vadose zone if proper conditions exist in the subsurface. If sufficient oxygen and indigenous microbes exist along with the occurrence of appropriate soil moisture, nutrients, pH conditions, and salinity, petroleum hydrocarbons can readily biodegrade in the vadose zone. While conditions conducive to biodegradation usually exist within the vadose zone, exceptions occur in California which preclude the adoption of a policy by DTSC that petroleum hydrocarbons always biodegrade in the vadose zone, posing no vapor intrusion risk. Therefore, petroleum hydrocarbons at sites in California must be evaluated for the possibility of vapor intrusion. To evaluate the vapor intrusion of petroleum hydrocarbons, subsurface contamination should be delineated by the collection of soil gas samples. Soil gas samples should be analyzed for the appropriate chemical indicators within the petroleum hydrocarbon mixture. These indicator compounds are usually benzene, ethyl benzene, toluene, xylene (BTEX), naphthalene, polynuclear aromatic hydrocarbons (PAHs) and fuel oxygenates, dependent upon the composition of the petroleum hydrocarbons. Likewise, the soil gas samples should also be analyzed for any biodegradation byproducts which may pose a health risk. (See Table 1 for chemicals to be considered for analysis.) Aerobic biodegradation of petroleum hydrocarbons will result in the consumption of oxygen and generation of carbon dioxide. These two geochemical indicator chemicals of aerobic biodegradation should be included in the soil gas sampling, to assess the potential for bioattenuation of subsurface petroleum vapors. To evaluate bioattenuation of volatile petroleum hydrocarbons in the subsurface, the measured vapor concentrations with depth should be compared with the theorized vertical concentration profile. This can be done using the procedures in Johnson et al. (1998). If there is good agreement between the observed vertical contaminant profile and the theorized diffusional contaminant profile, biodegradation is not playing a significant role in vapor transport. However, the comparison of observed contaminant profiles with theorized profiles should only be done if the site has reached steady-state conditions. Steady-state conditions can be inferred to exist at site if the petroleum release is at least three years old and the contaminant concentrations in groundwater have stable or decreasing trends. Otherwise, the soil gas and groundwater plumes will be inferred to be expanding and the documentation of bioattenuation will not be not possible. Hence, to effectively document the occurrence of bioattenuation, the installation and monitoring of permanent vadose zone monitoring points may be warranted. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 42 If there is disagreement between the observed vertical contaminant profile and the theorized diffusional contaminant profile, biodegradation of the petroleum hydrocarbon may be occurring in the subsurface. The occurrence of biodegradation can be evaluated with the oxygen and carbon dioxide data. When biodegradation occurs, the oxygen content of the vadose zone and the petroleum vapor concentration should sharply decrease and the carbon dioxide content should have an associated increase. In plotting the vapor, oxygen, and carbon dioxide concentrations with depth, it should be obvious that a zone exists in the subsurface where substantial changes in the concentration profiles occur. This area of concentration change, for the vapor, oxygen, and carbon dioxide, is the “zone of biodegradation”. If there is not a clear correlation in vapor, oxygen, and carbon dioxide profiles, biodegradation may not be occurring at the site and the unique contaminant profile with depth is attributable to an alternate cause. In evaluating sites for vapor intrusion, the “zone of biodegradation” in the subsurface must exist at sufficient depths below the surface so that anthropomorphic activities are unable to disturb the zone. If future development activities at a site can potentially affect the “zone of biodegradation,” DTSC will consider that the zone does not exist at the site for the evaluation of vapor intrusion. Activities that might affect the “zone of biodegradation” include, but are not limited to, removal of the zone for building construction, alteration of subsurface moisture conditions and the disruption of atmospheric oxygen migration by the placement of buildings and pavement at the surface. CONFIRMATION SAMPLING FOR THE COMPLETION OF REMEDIATION Remediation of VOC contamination may be warranted at some sites. Some of the approaches for the cleanup of subsurface VOC contamination are excavation, soil vapor extraction, and in-situ chemical oxidation. To verify that cleanup activities have reduced the subsurface VOC concentrations to levels protective of human health, including receptors subject to vapor intrusion, confirmation soil gas samples should be collected and analyzed for appropriate constituents of concern. For sites treated by in-situ chemical oxidation, the soil gas should also be tested for byproducts of the oxidation process. Soil gas samples should be collected using the procedures within DTSC’s Soil Gas Advisory (2003), and the density of sample collection should be appropriate to verify contaminant removal. Confirmation soil gas sampling after the completion of soil vapor extraction should take place after steady-state conditions are reached in the subsurface, which usually occurs within 12 to 16 months after system shutdown. REPORTING OF VAPOR INTRUSION DTSC anticipates that two documents will be submitted for agency review and approval during the process of evaluating a site for vapor intrusion. Prior to the initiation of any activities in the evaluation of vapor intrusion, workplans must be submitted to DTSC for review and approval. Workplans should be submitted for all phases of work, such as site characterization of subsurface contamination, evaluation of indoor air exposure through modeling, sampling for indoor air quality, sampling for long-term monitoring, and implementation of engineering controls. Likewise, reports describing the completion of all these activities, along with interpretations and conclusions derived from the data, should also be submitted to DTSC for approval. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 43 The following items should be included in a vapor intrusion risk assessment report that is submitted to DTSC: 1) Conceptual Site Model (CSM). The CSM should describe site conditions and state the assumptions made to generate the CSM. The CSM should describe the potential for exposure to hazardous contaminants based on the sources of contamination, the release mechanisms, the transport media, the exposure pathways, and the potential receptors. The CSM should include a diagrammatic or schematic presentation that relates the source of contamination to human receptors and identifies all the potential sources of contamination, the potentially contaminated media, and exposure pathways. 2) Laboratory Reports. All laboratory reports associated with environmental analyses, both analytical and geotechnical, should be submitted. The laboratory reports should include all the quality assurance and quality control information, such as the analytical method(s) used, laboratory control samples, matrix spikes, matrix spike duplicates, field duplicates, trip blanks, and equipments blanks. Additionally, the analytical detection limits should be annotated in the laboratory reports and the detection limits should be sufficiently low so that vapor intrusion evaluations can be properly conducted. 3) Maps of Contaminant Distribution. Plume maps should be provided with the spatial distribution of contaminants in the subsurface. The maps should display the contaminant distribution, both for soil gas and groundwater, through the depiction of isoconcentration contour maps for the constituents of concern. All data used to construct the contour maps should be clearly annotated on the maps. Ideally, the base map for plume presentation should be provided on an aerial photograph. 4) Modeling Input Parameters. All the input parameters used for vapor intrusion modeling should be provided, along with the technical justification for their selection. All the input parameters should be summarized into a single table. 5) Vapor Intrusion Modeling Results. The computational method used to quantify the risk associated vapor intrusion should be provided. If the USEPA Vapor Intrusion Model is used, copies of the EXCEL™ spreadsheets should be included. 6) Model Sensitivity Analysis. To understand the effect of the input parameters on the indoor air risk, a sensitivity analysis should be performed. The input parameters that should be evaluated, at a minimum, are soil volumetric water content, soil volumetric air content, total porosity, air permeability, indoor air exchange rate, and indoor-outdoor pressure differential. DTSC recommends that the sensitivity analysis be conducted in a similar manner to that described by Johnson (2002). To comply with the Geologist and Geophysicist Act, Section 7835, 16 CCR 3003(f)(2) and CCR 3003(h), and the Professional Engineers Act, Chapter 7 of the Business and Professions Code, any report submitted to DTSC that contains geologic or engineering conclusions, recommendations, or technical interpretations must be signed or stamped by a qualified California registered geologist or professional civil engineer who takes responsibility for the technical content of the report. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 44 PUBLIC OUTREACH Introduction When a vapor intrusion investigation leads to direct measurement of indoor air, a minimum of three public meetings may be necessary. The purpose of each meeting is slightly different. The first meeting is to discuss with the community the indoor sampling workplan and previous investigation results. The second meeting is to discuss the indoor air sampling results and future plans regarding the site, and additional meetings may be needed to discuss the results of additional air sampling or the remedy selection. DTSC’s Public Participation Policy and Procedures Manual (2001b) should be consulted. Following DTSC guidance, the optimal time to begin creating a trusting relationship is prior to fieldwork. The introductory meeting should explain the site investigation process and facilitate the collection of information from the community regarding their issues and concerns. As the investigation continues, the affected community should receive regular updates through fact sheets and telephone calls on the current findings and future activities. During these updates DTSC will continue to receive questions and comments from the affected community. To aid in what could be a long-term relationship, these questions and concerns must be addressed as they arise. This continuing dialogue helps to ensure that the community is aware of the facts and is prepared for future activities, such as interim actions and indoor vapor investigation. DTSC and responsible parties benefit by understanding the community and adjusting activities to minimize impact on the community when possible. Those issues that should be the focus of public meetings specific to discussing indoor air sampling are addressed here. It is important to understand that this is only one component of an ongoing investigation and therefore is part of a larger outreach effort for the entire project. Public Meetings The inevitable intrusion of indoor air sampling into the personal lives of community residents and business representatives requires multiple face-to-face meetings through all phases of data collection. Although the number of meetings will vary with each project, it is important to create time to provide the following: • Information regarding why the investigation is necessary. • Rationale for the investigation steps and the associated questionnaires. • Descriptions and operation of the indoor air sampling equipment. • Explanation of the analytical results. Each meeting should be conducted in candor and with empathy, thereby providing factual information to the community and creating trust. Information should be solicited from the community members on their preferences for these meetings. However, based upon experience, most community members require individual meetings and telephone discussions to fully address their questions. Based upon this, if the project entails working with a large number of residents and businesses, the first meeting should be held as a public forum and then breaking into small work groups to further discuss the community’s questions and concerns. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 45 The following is a suggested outline for public meetings. 1. Pre-Sampling Meeting a. Introductions: i. Roles and responsibilities. ii. Purpose of meeting. b. Site History: i. Describe past hazardous waste and industrial activities. ii. Describe results of groundwater and soil gas assessment (use a diagram to explain transport mechanism and extent of plume). iii. Provide information on the chemicals of concern. iv. Explain the results of the modeling or screening criteria. c. Indoor Air Investigation: i. Describe the sampling protocol. ii. Discuss the sampling schedule. d. Summarize meeting: i. Provide copies of indoor air surveys. ii. Provide a contact list with telephone numbers and email addresses. iii. Provide time for questions. 2. Meeting to Discuss Sampling Results a. Introductions: i. Roles and responsibilities. ii. Purpose of meeting. b. Explain how the preferential pathways were mapped and provide the results of the investigation. c. Explain results of indoor air investigation; the discussion should focus on what is known: i. The results of the pre-site survey. ii. The results of the site survey during sampling. iii. The results of the indoor air data. d. Explain the results of the risk assessment: i. Provide an overview of the risk assessment process, explained in terms understandable to the general public. ii. Explain the results of the risk assessment. e. Explain future actions. If no future action is needed, explain to the community why no further action is required. f. Summarize the meeting: i. Provide copies of indoor air surveys. ii. Provide a contact list with phone number and email address. iii. Provide time for questions. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 46 REFERENCES ATK Alliant Techsystems. 2003. Indoor Air Sampling; Dry Creek Road Property Cleanup. [www.atk.com/littleton/sampling.htm] Batterman, S., and H. Burge. 1995. Project Summary, HVAC System as Emission Sources Affecting Indoor Air Quality: A Critical Review. United States Environmental Protection Agency, Air and Energy Engineering Systems Laboratory. February 1995. California Code of Regulations. CCR. Title 8 Industrial Relations, section 5155. California Air Resources Board. 2001. Chlorinated Chemicals in Your Home; Indoor Air Quality Guideline. May 2001. California Energy Commission. 2001. Manual for Compliance with the 2001 Energy Efficiency Standards (for Nonresidential Buildings, High-Rise Residential Buildings, and Hotels/Motels). Document No. P400-01-032. August 2001. California Environmental Protection Agency. 1995a. Guidance Manual for Ground Water Investigations; Representative Sampling of Groundwater for Hazardous Substances. Jointly issued by the Regional Water Quality Control Boards, the State Water Resources Control Board, and the Department of Toxic Substances Control. July 1995. [www.dtsc.ca.gov/PublicationsForms/index.html] California Environmental Protection Agency. 1995b. Guidance Manual for Ground Water Investigations; Monitoring Well Design and Construction for Hydrogeologic Characterization. Jointly issued by the Regional Water Quality Control Boards, the State Water Resources Control Board, and the Department of Toxic Substances Control. July 1995. [www.dtsc.ca.gov/PublicationsForms/index.html] California Environmental Protection Agency. 2003. Advisory – Active Soil Gas Investigation. Jointly issued by the Regional Water Quality Control Board, Los Angeles Region and the Department of Toxic Substances Control. January 28, 2003. [www.dtsc.ca.gov/PublicationsForms/index.html] California Regional Water Quality Control Board, Los Angeles Region. 1997. Interim Guidance for Active Soil Gas Investigation. February 25, 1997. [www.swrcb.ca.gov/rwqcb4/html/ DTSC_RWQCB_SoilGasGuidelines.html] Case Studies and Answers for the DEP/LSPA Training Course, Addressing Indoor Air Contamination: Measurements & Models. Autumn 2001. Davis, B. K., J. F. Beach, M. J. Wade, A. K. Klein, and K. Hoch. 2002. Risk Assessment of Polychlorinated Biphenyls (PCBs) in Indoor Air. The Toxicologist, Supplement to Toxicological Sciences 66:106. Abstract Number 516. Davis, B. K., and M.J. Wade. 2003. Risk Assessment of Polychlorinated Biphenyls at Hazardous Waste Sites. The Toxicologist, Supplement to Toxicological Sciences 72:394. Abstract Number 1912. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 47 Dawson, H. 2004. Comments on Empirical Data / Methods. Presentation at the 14th Annual West Coast Conference on Soils, Sediments, and Water, Association of Environmental Health and Science; Vapor Intrusion Attenuation Workshop sponsored by the United States Environmental Protection Agency. San Diego, California. March 15 – 18, 2004. Department of Toxic Substances Control. 1994. Preliminary Endangerment Assessment Guidance Manual (A Guidance Manual for Evaluating Hazardous Substance Release Sites). California Environmental Protection Agency. January 1994. Department of Toxic Substances Control. 2001a. Information Advisory, Clean Imported Fill Material. California Environmental Protection Agency. October 2001. Department of Toxic Substances Control. 2001b. Public Participation Policy and Procedures Manual. California Environmental Protection Agency. October 2001. Department of Toxic Substances Control. 2004a. Advisory on Common Remedies for Methane in Subsurface Soils at School Sites, School Property Evaluation and Cleanup Division. California Environmental Protection Agency. November 2004. Department of Toxic Substances Control. 2004b. Guidance Document for the Implementation of United States Environmental Protection Agency Method 5035: Methodologies for Collection, Preservation, Storage, and Preparation of Soils to be Analyzed for Volatile Organic Compounds. California Environmental Protection Agency. November 2004. Fortmann, R., C. Gentry, K. Foarde, and D. Van Osdell. 1998. Project Summary, Results of a Pilot Field Study to Evaluate the Effectiveness of Cleaning Residential Heating and Air- Conditioning Systems and the Impact on Indoor Air Quality and System Performance. United States Environmental Protection Agency, National Risk Management Research Laboratory. May 1998. Gu, L., M. V. Swami, and V. Vasanth. 1996. Project Summary, Large Building HVAC Simulation. United States Environmental Protection Agency, National Risk Management Research Laboratory. November 1996. Hartman, B. 2004. How to Collect Reliable Soil-Gas Data for Risk-Based Applications – Specifically Vapor Intrusion; Part 3 – Answers to Frequently Asked Questions. LUSTLine Bulletin 48. November 2004. Hewitt, A. D. 1994. Losses of Trichloroethylene From Soil During Sample Collection, Storage and Laboratory Handling. U. S. Army Corps of Engineers, Cold Regions Research and Engineering Laboratory. Special Report 94-8. Hewitt, A. D. 1999. Storage and Preservation of Soil Samples for Volatile Compound Analysis. U. S. Army Corps of Engineers, Cold Regions Research and Engineering Laboratory. Special Report 99-5. Interstate Technology and Regulatory Council. 2004. Technical and Regulatory Guidance for Using Polyethylene Diffusion Bag Samplers to Monitor Volatile Organic Compounds in State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 48 Groundwater; Technical/Regulatory Guidelines. Diffusion Sampler Team. February 2004. Johnson, P. C., and R. A. Ettinger. 1991. Heuristic Model for Predicting the Intrusion of Contaminant Vapors into Buildings. Environmental Science and Technology, v. 25, n. 8, p. 1445 – 1452. Johnson, P. C., M. W. Kemblowski, and R. L. Johnson. 1999. Assessing the Significance of Subsurface Contaminant Vapor Migration to Enclosed Spaces: Site-Specific Alternatives to Generic Estimates. Journal of Soil Contamination, v. 8, no. 3, p. 389 – 421. Johnson, P. C. 2002. Identification of Critical Parameters for the Johnson and Ettinger (1991) Vapor Intrusion Model. American Petroleum Institute, Technical Bulletin No. 17. May 2002. Johnson, P. C., R. A. Ettinger, J. Kurtz, R. Bryan, and J. E. Kester. 2002. Migration of Soil Gas Vapors to Indoor Air: Determining Vapor Attenuation Factors Using a Screening- Level Model and Field Data from the CDOT-MTL Denver, Colorado. API Soil and Groundwater Technical Task Force Bulletin No. 16. American Petroleum Institute. April, 2002. Johnson, P. C and L. Deize-Abreu. 2003. Confusion? Delusion? What Do We Really Know About Vapor Intrusion. Groundwater Resources Association Symposium on Groundwater Contaminants; Subsurface Vapor Intrusion to Indoor Air: When Is Soil and Groundwater Contamination an Indoor Air Issue? September 30, 2003 (San Jose) and October 1, 2003 (Long Beach). Liikala, T. L., K. B. Olsen, S. S. Teel, and D. C. Logan. 1996. Volatile Organic Compounds: Comparison of Two Sample Collection and Preservation Methods. Environmental Science and Technology, v. 30, n. 12, p. 3441 – 3447. Massachusetts Department of Environmental Protection. 2002. Indoor Air Sampling and Evaluation Guide. Office of Research and Standards, Document No. WSC #02-430. April 2002. New York State Department Of Health. 2001. Indoor Air Sampling & Analysis Guidance. New York State Department Of Health, Division Of Environmental Health Assessment, Bureau Of Toxic Substance Assessment. August 8, 2001. Nazaroff, W. W. 1985. Radon Entry Into Houses Having a Crawl Space. Health Physics, v. 48, n. 3, p. 265 – 281. Nielson, K., and V. Rogers. 1995. Project Summary, Feasibility of Characterizing Concealed Openings in the House-Soil Interface for Modeling Radon Gas Entry. United States Environmental Protection Agency, Air and Energy Engineering Research Laboratory. May 1995. Office of Environmental Health Hazard Assessment. 2004. Human-Exposure-Based Screening Numbers Developed to Aid Estimation of Cleanup Costs for Contaminated Soil. Integrated Risk Assessment Section. November 2004. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 49 Pankow, J. F., and J. A. Cherry. 1996. Dense Chlorinated Solvents and other DNAPLs in Groundwater. Waterloo Press, Ontario, Canada, 552 p. Priest, J. B., J. McLaughlin, L. Christianson, A. Zhivov, M. McCullen, G. Chamberlin, M. Tumbleson, R. Maghirang, B. Shaw, Z. Li, J. Arogo, and R. Zhang. 1995. Project Summary, Ventilation Technology System Analysis. United States Environmental Protection Agency, Air and Energy Engineering Systems Laboratory. June 1995. Puls, R. W., and M. J. Barcelona. 1995. Low-Flow (Minimal Drawdown) Ground-Water Sampling Procedures. U.S. EPA Ground Water Issue, Document No. EPA/540/S-95/504. December 1995. Samfield, M. 1995. Project Summary, Air Infiltration Measurements Using Tracer Gases: A Literature Review. United States Environmental Protection Agency, Air and Energy Engineering Research Laboratory. February 1995. Samfield, M. 1996. Project Summary, HVAC systems as a Tool in Controlling Indoor Air Quality; A Literature Review. United States Environmental Protection Agency, National Risk Management Research Laboratory. January 1996. Sparks, L. E. 1996. Project Summary, IAQ Model for Windows, RISK Version 1.0: User Manual. United States Environmental Protection Agency, National Risk Management Research Laboratory. May 1996. United States Department of Energy. 1997. Site Conceptual Exposure Model Builder; User Manual. Office of Environmental Policy and Assistance, RCRA/CERCLA Division, EH- 413, Washington, DC. July 1997. United States Environmental Protection Agency. 1989. Risk Assessment Guidance for Superfund, Volume I Human Health Evaluation Manual (Part A), Document No: EPA/540/1-89/002. December 1989. United States Environmental Protection Agency. 1991. Radon-Resistant Construction Techniques for New Residential Construction; Technical Guidance. Office of Research and Development; Document No. EPA/625/2-91/032. February 1991. United States Environmental Protection Agency. 1992a. Assessing Potential Indoor Air Impacts for Superfund Sites; Air/Superfund National Technical Guidance Study Series. Office of Air Quality, Planning and Standards, Research Triangle Park, Document No. EPA-451/R-92-002. September 1992. United States Environmental Protection Agency. 1992b. Overview of Air Pathway Assessments for Superfund Sites (Revised), Volume 1; Air/Superfund National Technical Guidance Study Series. Agency Office of Air Quality, Planning and Standards, Research Triangle Park, Report No. ASF-1a. November 1992. United States Environmental Protection Agency. 1993. Radon Prevention in the Design and Construction of Schools and Other Large Buildings. Office of Research and Development, Document No. EPA/625/R-92/016. January 1993. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 50 United States Environmental Protection Agency. 1994. Guidance for the Data Quality Objectives Process (EPA QA/G-4). Office of Research and Development, Document No. EPA/600/R-96/055. September 1994. United States Environmental Protection Agency. 1995a. Review of Mathematical Modeling for Evaluating Soil Vapor Extraction Systems. Office of Research and Development, Document No. EPA/540/R-95-513. March 1995. United States Environmental Protection Agency. 1995b. Passive Radon Control System for New Construction. Indoor Environmental Division, Office of Radiation and Indoor Air, Document No. EPA 402-95012. May 1995. United States Environmental Protection Agency. 1996. Method 8260B; Volatile Organic Compounds by Gas Chromatography / Mass Spectrometry (GC/MS); SW-846, Test Methods for Evaluating Solid Waste, Physical / Chemical Methods. Office of Solid Waste. December 1996. United States Environmental Protection Agency. 1997a. Expedited Site Assessment Tools For Underground Storage Tank Sites: A Guide for Regulators. Office of Underground Storage Tanks, Document No. EPA 510-B-97-001. March 1997. United States Environmental Protection Agency. 1997b. Exposure Factors Handbook. Office of Research and Development. National Center for Environmental Assessment, Document No. EPA/600/P-95/002Fa. August 1997. United States Environmental Protection Agency. 1999a. Compendium Method TO-14A, Determination Of Volatile Organic Compounds (VOCs) In Ambient Air Using Specially Prepared Canisters With Subsequent Analysis By Gas Chromatography; Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, Second Edition. Center for Environmental Research Information, Office of Research and Development. January 1999. United States Environmental Protection Agency. 1999b. Compendium Method TO-15, Determination Of Volatile Organic Compounds (VOCs) In Air Collected In Specially- Prepared Canisters And Analyzed By Gas Chromatography/Mass Spectrometry (GC/MS); Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, Second Edition. Center for Environmental Research Information, Office of Research and Development. January 1999. United States Environmental Protection Agency. 2001. Building Radon Out, A Step-by- Step Guide On How To Build Radon Resistant Homes. Office of Air and Radiation; Document No. EPA/402-K-01-002. April 2001. United States Environmental Protection Agency. 2002a. Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance). Office of Solid Waste and Emergency Response. November 29, 2002. United States Environmental Protection Agency. 2002b. Ground-Water Sampling Guidelines for Superfund and RCRA Project Managers: Ground Water Forum Issue State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 51 Paper. Office of Solid Waste and Emergency Response, Document No. 542/S-02/001. May 2002. United States Environmental Protection Agency. 2002c. Closed-System Purge-and-Trap Extraction for Volatile Organics in Soil and Waste Samples; SW-846, Test Methods for Evaluating Solid Waste, Physical / Chemical Methods. Office of Solid Waste. June 2002. United States Environmental Protection Agency. 2002d. Region 9 Preliminary Remediation Goals (PRGs). USEPA Region IX Solid and Hazardous Waste Program. October 1, 2002. United States Environmental Protection Agency. 2003a. Vapor Intrusion and RCRA Corrective Action (CA); Environmental Indicators (EI) Fact Sheet. Office of Emergency and Remedial Response. June 17, 2003. United States Environmental Protection Agency. 2003b. User’s Guide for Evaluating Subsurface Vapor Intrusion into Buildings. Office of Emergency and Remedial Response. June 19, 2003. United States Environmental Protection Agency. 2004. User Guide, ProUCL Version 3.0. Office of Research and Development; National Exposure Research Laboratory. April 2004. Vitale, R. J., R. Forman, and L. Dupes. 1999. Comparison of VOC Results Between Methods 5030 and 5035 on a Large Multi-State Hydrocarbon Investigation. Environmental Testing and Analysis, January 1999, p. 18 – 39. Williamson, A. D., B. E. Pyle, S. E. McDonough, and C. S. Fowler. 1997. Project Summary, Active Soil Depressurization (ASD) Demonstration in a Large Building. United States Environmental Protection Agency, National Risk Management Research Laboratory. February 1997. Wisconsin Department of Health and Family Services. 2003. Chemical Vapor Intrusion and Residential Indoor Air; Guidance for Environmental Consultants and Contractors. State of Wisconsin, Department of Health and Family Services, Division of Public Health. February 13, 2003. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 52 FIGURE 1 – VAPOR INTRUSION TO INDOOR AIR ASSESSMENT Spill / Release Identified Site Characterization Site Candidate for Vapor Intrusion? Imminent Hazard in Building? Does the Site Pass a Generic J&E evaluation? Is Additional Site Data Needed? Does the Site Pass a Site-Specific J&E evaluation? Conduct Building Screening Collect Indoor Air Samples / Evaluate Data Indoor Air Concentrations Acceptable? Mitigate Indoor Air Exposure / Conduct Long Term Monitoring No Further Consideration For Indoor Air Risk Current Incomplete Exposure Pathway Yes Yes Yes No Yes No Yes No No No Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Step 11 No Yes Note: Shaded steps do not apply to future building scenarios Collect Additional Site Data Emergency Remedial Action State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 53 FIGURE 2 – DIAGRAM OF AIR FLOW THROUGH A BUILDING (Taken from ATK Alliant Techsystems, 2003). State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 54 FIGURE 3 – UTILITY CORRIDOR DECISION TREE Are utilities corridors present based on existing information? Is there enough information for a conceptual site model (CSM)? Are utilities corridors potentially a preferential migration pathway? Are vapors present in the utility corridors? Gather existing information (maps, county files, utility hotlines, etc.) Perform additional field investigation to complete the CSM Conduct field investigation of utility corridors (active and/or passive soil gas survey) Develop and implement remedial actions to mitigate vapors in the utility corridors Yes No Yes Yes Utility corridors are not of concern No Yes No No Do vapors pose an acceptable risk to indoor occupants? Yes No State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 55 TABLE 1 - List of Chemicals to be Considered for the Vapor Intrusion Pathway CAS Number Chemical 630206 1,1,1,2-Tetrachloroethane 71556 1,1,1-Trichloroethane 79345 1,1,2,2-Tetrachloroethane 76131 1,1,2-Trichloro-1,2,2-trifluoroethane 79005 1,1,2-Trichloroethane 75343 1,1-Dichloroethane 75354 1,1-Dichloroethylene 96184 1,2,3-Trichloropropane 120821 1,2,4-Trichlorobenzene 95636 1,2,4-Trimethylbenzene 106934 1,2-Dibromoethane (ethylene dibromide) 95501 1,2-Dichlorobenzene 107062 1,2-Dichloroethane 78875 1,2-Dichloropropane 108678 1,3,5-Trimethylbenzene 106990 1,3-Butadiene 541731 1,3-Dichlorobenzene 542756 1,3-Dichloropropene 106467 1,4-Dichlorobenzene 123911 1,4-Dioxane 109693 1-Chlorobutane 126998 2-Chloro-1,3-butadiene (chloroprene) 95578 2-Chlorophenol 75296 2-Chloropropane 91576 2-Methylnaphthalene 79469 2-Nitropropane 83329 Acenaphthene 75070 Acetaldehyde 67641 Acetone 75058 Acetonitrile 98862 Acetophenone 107028 Acrolein (Propenal) 107131 Acrylonitrile 309002 Aldrin 319846 alpha-HCH (alpha-BHC) 100527 Benzaldehyde 71432 Benzene 205992 Benzo(b)fluoranthene 100447 Benzylchloride 92524 Biphenyl 111444 Bis(2-chloroethyl)ether 75274 Bromodichloromethane 75252 Bromoform 75150 Carbon disulfide 56235 Carbon tetrachloride 57749 Chlordane 108907 Chlorobenzene 124481 Chlorodibromomethane 75456 Chlorodifluoromethane 75003 Chloroethane (ethyl chloride) State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 56 67663 Chloroform 218019 Chrysene 156592 cis-1,2-Dichloroethylene 123739 Crotonaldehyde (2-butenal) 98828 Cumene (Isopropylbenzene) 72559 DDE 132649 Dibenzofuran - Dichlorobiphenyl (PCB) 75718 Dichlorodifluoromethane 60571 Dieldrin 108203 Diisopropyl Ether (DIPE) 115297 Endosulfan 60297 Ethyl ether 637923 Ethyl tert-Butyl Ether (ETBE) 141786 Ethylacetate 100414 Ethylbenzene 75218 Ethylene oxide 97632 Ethylmethacrylate 86737 Fluorene 110009 Furan 58899 gamma-HCH (Lindane) 76448 Heptachlor 87683 Hexachloro-1,3-butadiene 118741 Hexachlorobenzene 77474 Hexachlorocyclopentadiene 67721 Hexachloroethane 110543 Hexane 74908 Hydrogen cyanide 78831 Isobutanol 7439976 Mercury (elemental) 126987 Methacrylonitrile 72435 Methoxychlor 79209 Methyl acetate 96333 Methyl acrylate 74839 Methyl bromide 74873 Methyl chloride (chloromethane) 1634044 Methyl tert-Butyl Ether (MTBE) 108872 Methylcyclohexane 74953 Methylene bromide 75092 Methylene chloride 78933 Methylethylketone (2-butanone) 108101 Methylisobutylketone (4-methyl-2-pentanone) 80626 Methylmethacrylate - Monochlorobiphenyl (PCB) 108383 m-Xylene 91203 Naphthalene 104518 n-Butylbenzene 98953 Nitrobenzene 103651 n-Propylbenzene 88722 o-Nitrotoluene 95476 o-Xylene 106423 p-Xylene 129000 Pyrene State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 57 135988 sec-Butylbenzene 100425 Styrene 994058 Tert-Amyl Methyl Ether (TAME) 75650 Tert-Butyl Alcohol (TBA) 98066 tert-Butylbenzene 127184 Tetrachloroethylene 108883 Toluene 156605 trans-1,2-Dichloroethylene 79016 Trichloroethylene 75694 Trichlorofluoromethane 108054 Vinyl acetate 75014 Vinyl chloride (chloroethene) CAS = Chemical Abstracts Service Table 1 was generated from the chemicals listed in the USEPA Vapor Intrusion Guidance Document (USEPA, 2002a), with the addition of fuel oxygenates and two polychlorinated biphenyl congeners due to the volatility and toxicity of monochlorobiphenyl and dichlorobiphenyl (Davis et al., 2002; Davis and Wade, 2003). State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 58 TABLE 2 - Attenuation Factors for Preliminary Screening Evaluations (Step 5) Building Scenario Building Type Foundation Configuration Attenuation Factor Slab-on-Grade 0.002 Crawl space 0.002 Residential Basement 0.01 Existing Commercial Slab-on-Grade 0.001 Slab-on-Grade 0.0009 Crawl space 0.0009 Residential Basement 0.01 Future Commercial Slab-on-Grade 0.0004 Derivation of the attenuation factors can be found in Appendix B and OEHHA (2004). State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 59 TABLE 3 - Input Parameters for Site-Specific Screening Evaluations (Step 7) Primary Input Parameters Site-Specific Evaluation Basis for Site-Specific Parameter Cgw Groundwater concentrations** Statistical approximation* - Csg Soil gas concentrations** Statistical approximation* - θt Soil total porosity Site-specific Use ASTM D854 θw Soil volumetric water content Site-specific Use ASTM D2216 θa Soil volumetric air content Site-specific Calculate from θw ρs Soil bulk density Site-specific Use ASTM 2937 θtcap Capillary zone total porosity Site-specific Use ASTM D854 θwcap Capillary zone volumetric water content Site-specific Calculate from USEPA, 2003 θacap Capillary zone volumetric air content Site-specific Calculate from θwcap Lcap Thickness of the capillary fringe Site-specific Calculate from Fetter (1994) k Soil permeability Site-specific In-situ measurement (Appendix I) foc Soil fraction organic carbon Site-specific Use Walkley-Black method ° T Soil and groundwater temperature Site-specific Use map in Appendix D ∆P Indoor – outdoor pressure differential# 40 g/cm-s2 USEPA, 2002 η Crack-to-total area ratio# 0.005 Johnson, 2002 Eb Indoor air exchange rate – residential 0.5 / hour USEPA, 1997 (California data) Eb Indoor air exchange rate - commercial 1.0 / hour CEC, 2001 Lcrack Foundation slab thickness Site-specific - Lb,Wb,Hb Building dimensions# Site-specific - Foundation depth below grade – building with no basement 15 cm USEPA, 2002 Lf Foundation depth below grade – building with basement 200 cm USEPA, 2002 Lt Distance from foundation to source Site-specific - Lwt Distance from foundation to groundwater Site-specific - USEPA = United States Environmental Protection Agency CEC = California Energy Commission cm = centimeters g/cm-s2 = grams per centimeter – seconds squared Note: * For existing buildings, the contaminant source term should be approximated with the 95th percent upper confidence limit, which can be done with ProUCL (USEPA, 2004). ** For future buildings, the maximum soil gas and groundwater concentrations should be used rather than a statistical approximation of the contaminant source. # For future buildings, a soil gas advection rate of 5 liters per minute should be used, as proportionally increased for future building size, rather than the defaults for indoor – outdoor pressure differential, crack- to-total area ratio, and foundation thickness. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 A - 1 APPENDIX A - FLUX CHAMBERS IN RISK DETERMINATION Background on Flux Chambers The development of the emission isolation flux chamber rose from the need to assess the vapor emissions from contaminated soil and other environmental media at Superfund sites as part of remedial investigation efforts. To measure emissions from soil, an enclosure or chamber is used to isolate a soil surface. The flux chamber approach gives a direct measurement of the subsurface contaminant flux at the soil-air interface as driven by diffusion and atmospheric conditions. The flux chamber results are then used to evaluate the impact of contaminated soil and other media on ambient air quality. The assessment of emissions of volatile organic compounds (VOCs) with flux chambers are usually done in conjunction with either TO-14A (United States Environmental Protection Agency [USEPA], 1999) or TO-15 (USEPA, 1999), as appropriate, yielding analytical detection limits of 0.1 to 0.001 micrograms per liter (µg/L) for the air within a flux chamber. There are two types of flux chamber methods; the static chamber method and the dynamic chamber method. For the dynamic method, a sweep gas is continuously introduced into the chamber during the incubation period and an equivalent amount of chamber gas is allowed to escape. The chamber is assumed to reach a steady-state condition after the chamber has been swept by the sweep gas four or five times. At steady-state conditions, the contaminant concentration in the outlet gas is equivalent to the concentration in the chamber. The outlet gas can either be sampled periodically over the incubation time at four to six hours intervals, or sampled continuously through capture within a Summa™ canister, thus yielding an integrated sample. In the static chamber method, there is no introduction of a sweep gas into the chamber during the incubation period. Contaminants migrate into the static chamber and the contaminant concentration builds-up over time. Discrete samples for analysis are withdrawn either at the end of the incubation period or at regular intervals during the incubation period. The required equipment for static testing is very simple, consisting essentially of a collection container with sampling ports. USEPA Publications on the Use of Flux Chambers Radian Corporation, under contract to USEPA, developed procedures for the use of emission isolation flux chambers for evaluating the flux of chemicals from the soil-air interface (USEPA, 1986). While the Radian document describes the construction of flux chambers and procedures for the collection of flux chamber data in the field, the USEPA document is a technical reference only. The document provides no information concerning the use of flux chambers to quantify human health risk associated with vapor emissions from the subsurface. Subsequent USEPA technical documents (USEPA 1990, 1992b, and 1992c) discuss the general application of flux chambers for evaluating the impact of contaminated soil and other media on ambient air quality. These subsequent documents do not address the use of flux chambers for the evaluation of vapor intrusion. To date, USEPA has not developed procedures for the use of flux chambers for the evaluation of the vapor intrusion pathway and the use of flux chambers as a mechanism to quantify the health risk for indoor human receptors. It should be noted, however, that USEPA (1992a) recommended that flux chambers should not be used to evaluate the vapor intrusion to indoor air pathway. The 1992 USEPA State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 A - 2 document states that “flux chambers. . . may give significantly negatively biased results if building underpressurization is exerting an effect on soil gas flow rates” and that “low permeability zones near the surface, frozen ground, or wet surfaces may also result in low flux chamber results.” The 1992 USEPA guidance document recommends that soil gas samples be collected as a mechanism to evaluate vapor intrusion to indoor air. In 2002, USEPA generated regulatory guidance for the evaluation of vapor intrusion (USEPA, 2002b). The document was generated as official USEPA guidance and was noticed in the Federal Register on November 29, 2002. The guidance document recommends quantifying subsurface contaminant sources through soil gas sampling and groundwater sampling and then using this data as a means to evaluate the indoor air exposure pathway. The 2002 USEPA guidance document provides screening values for both soil gas and groundwater that are protective of human exposure to vapor intrusion from subsurface contamination. No where in the guidance document is information provided on using flux chambers to quantify the impact of subsurface contamination on indoor air receptors. However, USEPA implies that flux chamber measurements can be used as an additional line of evidence to soil gas for evaluating vapor flux from the subsurface at brownfield sites where no buildings exist. Accordingly, in their guidance document, USEPA did not recommend flux chambers as a primary mechanism to evaluate the vapor intrusion to indoor air pathway. Indoor Flux Chamber Measurements for the Evaluation of Indoor Air The soil gas entry points into a building are along cracks or voids at the structural footings, along the cracks or voids at the foundation-wall interface, along the utility conduit entry points into the structure, and at the cracks or voids within the foundation and basement walls. The design of the flux chamber precludes the use of the chamber in all these scenarios except for foundation cracks or voids where the chambers can be placed directly on flat-lying cracks or voids. Therefore, testing only the foundation cracks or voids within a building will not yield representative samples for indoor air quality evaluation due to the existence of other potential soil gas entry points. Furthermore, even if foundation cracks or voids are the sole entry point for soil gas into a building, difficulties still exist in using flux chambers to evaluate indoor air quality. When evaluating a foundation slab, selection of the flux chamber measurement locations is crucial to the success of the evaluation. Without access to the entire foundation, it becomes impossible to select appropriate areas for testing. Hence, for residential structures where the foundation slab is entirely covered with carpet, tile, or linoleum, representative flux chamber sampling is not possible due to an unwillingness to remove all floor covering in a residential building. Additionally, even if an entire foundation slab is available for flux chamber testing in a residential or commercial building, it is difficult to know which subset of cracks or voids are responsible for the degradation of indoor air quality. DTSC recommends that indoor air quality evaluations be conducted with a method other than flux chambers for the evaluation for the vapor intrusion pathway. Flux chamber measurements cannot evaluate all possible soil gas entry points into a building due to design limitations of the chamber and it is doubtful that flux chambers can measure the total flux into a building due to the inability to place the chambers on the slab cracks or voids that are representative of vapor flux into the building. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 A - 3 Soil Flux Chamber Measurements for the Evaluation of Indoor Air Flux chamber measurements of open soil surfaces may not be representative of actual contaminant fluxes into buildings. The measured flux could be biased high due to the lack of a building foundation impeding the movement of vapors. Conversely, the measured flux could be biased low because the flux chamber cannot duplicate the pressure-induced advective flow caused by a building’s depressurization. When using flux chamber measurements on open soil, one method to account for vapor attenuation over the foundation slab is to divide the flux measurements by a foundation crack-to-total area ratio (Copeland et al., 2002), which is usually taken as 0.01 (American Society for Testing and Materials [ASTM], 1995; ASTM, 2000). While this approach has been used in the past as a method to determine indoor air concentrations from outdoor flux chamber measurements, the approach has not been field validated. There are no peer reviewed scientific articles that specifically provide documentation that this procedure is appropriate for evaluating risk to indoor receptors. The intrinsic design of the flux chamber only allows for the measurement of vapors moving into the chamber by diffusion or by atmospheric driven advection due to ambient temperature and pressure changes. Hence, the flux chamber cannot measure vapor movement driven by a building’s heating and ventilation system. To address the issue of building induced advection flow, Sheldon and Schmidt (2002) developed and tested a procedure that allows the flux chamber to depressurize to values observed in buildings. The intent of the depressurization procedure is to create a “mini-building” in which flux measurements could be made. However, the induced depressurization of the flux chamber to mimic building depressurization will need field validation prior to regulatory acceptance. This limitation, and the limitation associated with quantification of the foundation attenuation, seriously inhibits the flux chamber as a means to directly evaluate vapor intrusion to indoor air. Hence, flux chamber measurements of open soil surfaces should only be used qualitatively for vapor intrusion evaluations. Soil Flux Chamber Measurements for the Evaluation of Outdoor Air The testing of surface soil with flux chambers yields the amount of VOCs being released through diffusion and atmospheric conditions at the soil-air interface. From the soil flux data, the VOC concentrations in ambient air can be estimated. Using an appropriate box model, along with the flux chamber measurements, the ambient concentrations of VOCs within the breathing zone in outdoor air can be determined. Therefore, flux chamber measurements can be used to satisfactorily quantify human exposure to outdoor air contaminated from VOCs from subsurface sources. This exposure pathway, subsurface soil to outdoor air, is the sole exposure pathway where flux chambers measurement can be used to quantify exposure inhalation from vapors migrating from the subsurface. Additional Concerns About the Use of Flux Chambers Heating of Flux Chambers During Sampling Surface warming on metal flux chambers due to direct sunlight and ambient conditions, and associated greenhouse effects on transparent chambers, may cause the internal air temperature inside a flux chamber to increase during sample collection. As temperatures increase inside the flux chamber, the air pressure inside the flux chamber may also State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 A - 4 increase. If internal heating is significant, an associated back-pressure may inhibit the diffusional movement of air from the subsurface into the chamber if the sweep gas cannot compensate for the pressure buildup. Therefore, the flux chamber should be shaded from direct sunlight during sampling and should not be used on days with extreme temperature variations. In typical applications of the flux chamber, measurements of the internal air pressure are not taken so there is no indication if air is exiting into the soil, inhibiting vapor flux. Ideally, these measurements should be taken to verify the air mass balance during the operation of the flux chamber. Additionally, no peer reviewed scientific literature is available that evaluates the heating of flux chambers during sample collection. Rainfall Events A rainfall event of 0.3 inches of water has been observed to decrease emission rates into flux chambers by ninety percent, and a minimum of seven days of hot, sunny weather were required before gas emission rates from soil returned to values equal to that before the rainfall event (USEPA, 1986). Hence, outdoor flux chamber measurements should only be taken after warm dry weather. Additionally, due to moisture blockage of potential soil gas emissions, flux chamber measurements should not be taken in areas subject to irrigation or in areas of commercial or residential landscaping. Atmospheric Pressure Effects The work by Massmann and Farrier (1992) indicates that “fresh” atmospheric air may migrate several meters into the subsurface during a barometric pressure cycle. Massmann and Farrier concluded that the intrusion of atmospheric air into the subsurface may affect the results of soil gas surveys because the concentration of VOCs within the subsurface may be lowered when barometric pressures are high. Likewise, flux chamber measurements would also be effected by barometric pressure changes. The occurrence of these phenomena has not been addressed within the scientific literature. However, the effects of barometric pumping on sampling results for indoor air have been recognized by other state agencies (Massachusetts Department of Environmental Protection, 2002). Thus, the proper deployment of flux chambers to obtain representative samples as a function of barometric pressure variations is not well understood. Condensation of Water During Sampling During sample collection, condensation may occur inside the flux chamber due to changing ambient pressure and temperature conditions. Condensation may reduce VOC concentrations in the flux chamber air due to partitioning of water soluble VOCs into the condensation during chamber deployment. Hence, the occurrence of condensation should be noted in the field and reported to DTSC with the understanding that the sampling results may be biased low due to chemical partitioning. REFERENCES American Society for Testing and Materials. 1995. Standard Guide for Risk-Based Corrective Action Applied at Petroleum Release Sites. American Society for Testing and Materials E1739-95. Philadelphia, PA. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 A - 5 American Society for Testing and Materials. 2000. Standard Guide for Risk-Based Corrective Action. American Society for Testing and Materials E2081-00. Philadelphia, PA. Copeland, T., C. E. Schmidt, J. Van de Water, and M. Manning. 2002. Predicting Potential Exposure for the Occupants in Future Buildings Using Direct Measurement and Predictive Modeling Techniques. Proceedings of the 95th Annual Meeting of the Air and Waste Management Association; Paper No. 43141. Baltimore, Maryland. June 2002. Hartman, B. 2003. How to Collect Reliable Soil-Gas Data for Upward Risk Assessments, Part 2: Surface Flux-Chamber Method. United States Environmental Protection Agency LUSTLine Bulletin 44. August 2003. Massachusetts Department of Environmental Protection. 2002. Indoor Air Sampling and Evaluation Guide; WSC Policy #02-430. Office of Research and Standards, Massachusetts Department of Environmental Protection. April 2002. Massmann, J., and D. F. Farrier. 1992. Effects of Atmospheric Pressures on Gas Transport in the Vadose Zone. Water Resources Research, v. 28, n. 3, p. 777 – 791. Sheldon, A., and C. E. Schmidt. 2002. Evaluation of an Underpressurized Emission Flux Chamber for Measuring Potential Subsurface Vapor Intrusion Into Buildings. Proceeding of the 95th Annual Meeting of the Air and Waste Management Association; Paper No. 42690. Baltimore, Maryland. June 2002. United States Environmental Protection Agency. 1986. Measurement of Gaseous Emission Rates From Land Surfaces Using an Emission Isolation Flux Chamber, Users Guide. EPA Environmental Monitoring Systems Laboratory, Las Vegas, Nevada, EPA Contract No. 68-02-3889, Work Assignment 18, Radian Corporation. Document No. EPA/600/8- 86/008. February 1986. United States Environmental Protection Agency. 1990. Estimation of Baseline Air Emissions at Superfund Sites, Volume 2; Air/Superfund National Technical Guidance Study Series. United States Environmental Protection Agency, Office of Air Quality, Planning and Standards, Research Triangle Park. Document No. EPA-450/1-89-002a. August 1990. United States Environmental Protection Agency. 1992a. Assessing Potential Indoor Air Impacts for Superfund Sites; Air/Superfund National Technical Guidance Study Series. Office of Air Quality, Planning and Standards, Research Triangle Park. Document No. EPA-451/R-92-002. September 1992. United States Environmental Protection Agency. 1992b. Overview of Air Pathway Assessments for Superfund Sites (Revised), Volume 1; Air / Superfund National Technical Guidance Study Series. Agency Office of Air Quality, Planning and Standards, Research Triangle Park. Report No. ASF-1a. November 1992. United States Environmental Protection Agency. 1992c. Engineering Bulletin: Air Pathway Analysis. Office of Emergency and Remedial Response. Document No. EPA/540/S- 92/013. November 1992. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 A - 6 United States Environmental Protection Agency. 1999a. Compendium Method TO-14A, Determination Of Volatile Organic Compounds (VOCs) In Ambient Air Using Specially Prepared Canisters With Subsequent Analysis By Gas Chromatography; Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, Second Edition. Center for Environmental Research Information, Office of Research and Development. January 1999. United States Environmental Protection Agency. 1999b. Compendium Method TO-15, Determination Of Volatile Organic Compounds (VOCs) In Air Collected In Specially- Prepared Canisters And Analyzed By Gas Chromatography/Mass Spectrometry (GC/MS); Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, Second Edition. Center for Environmental Research Information, Office of Research and Development. January 1999. United States Environmental Protection Agency. 2002. Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance). Office of Solid Waste and Emergency Response. November 2002. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 B - 1 APPENDIX B – DEFAULT ATTENUATION FACTORS Future Residential Slab-On-Grade Buildings Pursuant to Senate Bill 32 (SB 32), the California Land Environmental Restoration and Reuse Act, the Office of Environmental Health Hazard Assessment (OEHHA) published a list of risk-based screening numbers (OEHHA 2004). Numerous exposure pathways were evaluated in calculating the SB 32 screening numbers, including vapor intrusion to indoor air. To evaluate vapor intrusion for future slab-on-grade buildings, OEHHA used the Johnson and Ettinger (J/E) (1991) model as programmed into Microsoft EXCEL™ by the United States Environmental Protection Agency (USEPA Vapor Intrusion Model) (USEPA, 2003). The model input parameters and the rationale for their selection can be found in the OEHHA document. Additionally, OEHHA used toxicity factors specific to California. The average attenuation factor for future residential slab-on-grade buildings from the OEHHA document is 0.0009. Existing Residential Slab-On-Grade Buildings OEHHA published a list of risk-based screening numbers for vapor intrusion into existing residential slab-on-grade buildings, and again, used the USEPA Vapor Intrusion Model for the evaluation. The model input parameters and the rationale for their selection can be found in the OEHHA document. Additionally, OEHHA used toxicity factors specific to California. The average attenuation factor for existing residential slab-on-grade buildings from the OEHHA document is 0.002. Buildings With Crawl Spaces No vapor attenuation should be assumed over a building’s crawl space. Hence, future and existing buildings with crawl spaces should be evaluated as though constructed with a slab- on-grade foundation. This implies that the attenuation over the crawl space is 1.0 and this approach is consistent with USEPA guidance (2002a). Likewise, the empirical data shown at the 2004 Conference of the Association of Environmental Health and Science indicates that crawl space attenuation is minimal (Dawson, 2004). Thus, the attenuation factors for residential buildings with crawl spaces, whether they are future or existing structures, are equal to the attenuation factors for slab-on-grade structures. Buildings With Basements The attenuation factor for residential buildings with basements is taken from the USEPA empirical database on vapor intrusion. Because basements are often poorly ventilated, DTSC assumed that subslab attenuation factors are appropriate for evaluating residential buildings with basements. USEPA (2002a) recommends an attenuation factor of 0.1 for subslab attenuation. More recently, however, empirical data shown at the 2004 Conference of the Association of Environmental Health and Science suggested that subslab attenuation factors may be closer to 0.01 (Dawson, 2004). Accordingly, an attenuation factor of 0.01 should be used when evaluating subslab attenuation and hence basement attenuation. This is appropriate in that many of the sites in the USEPA database related to subslab attenuation are from buildings with basements. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 B - 2 Existing and Future Commercial Buildings The attenuation factors for existing and future commercial buildings were derived by OEHHA in a similar fashion as the residential attenuation factors. The residential attenuation factors for slab-on-grade buildings were decreased to account for the higher indoor air exchange rates for commercial buildings. Default air exchange rates for residential buildings is 0.5 air exchanges per day while commercial air exchanges rates are 1.0 air exchange per day. Likewise, OEHHA decreased the exposure frequency and exposure duration of the buildings occupancts to reflect the commercial worker scenario. Hence, the attenuation factors for future and existing commercial buildings are 0.0004 and 0.001, respectively. REFERENCES Dawson, H. 2004. Comments on Empirical Data / Methods. Presentation at the 14th Annual West Coast Conference on Soils, Sediments, and Water, Association of Environmental Health and Science; Vapor Intrusion Attenuation Workshop sponsored by the United States Environmental Protection Agency. San Diego, California. March 15 – 18, 2004. Office of Environmental Health Hazard Assessment. 2004. Human-Exposure-Based Screening Numbers Developed to Aid Estimation of Cleanup Costs for Contaminated Soil. Integrated Risk Assessment Section. November 2004. United States Environmental Protection Agency. 2002a. Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance). Office of Solid Waste and Emergency Response. November 29, 2002. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 C - 1 APPENDIX C – HUMAN RISK ASSESSMENT When a site or facility first comes to the attention of the DTSC, the question to be answered is, has there been a release of hazardous chemicals that could pose a risk to human health or the environment and require further evaluation by and oversight of the DTSC? During this initial stage, as described in the DTSC Preliminary Endangerment Assessment Guidance Manual, a health screening evaluation may be performed, applying conservative default assumptions to a limited data set, to answer that question. If this screening evaluation shows that the risks are insignificant, than the DTSC can recommend no further action, and the site is released from DTSC oversight requirements. An insignificant risk resulting from long-term exposure to chemicals present is one in which the theoretical excess risk of getting cancer is less than one-in-a-million (10-6) or the hazard index is less than one for non-cancer effects. However, if the screening evaluation shows that the theoretical excess cancer risk is greater than 10-6 or the hazard index is greater than one, further investigative studies are conducted in order to fully characterize the site, determine the extent of contamination, and reevaluate the risk and hazard posed by the contaminants present by performing a health risk assessment. If volatile organic chemicals are present, the health risk assessment would include the evaluation of the following exposure pathways: • Inhalation of vapors that have intruded to indoor air from the subsurface (soil, soil gas, shallow groundwater). • Inhalation of vapors outdoors coming from the subsurface (soil, soil gas, shallow groundwater). • Inhalation of vapors coming from groundwater contaminated with volatile organic chemicals being used as tap water (in showering and general household use), • Ingestion of groundwater contaminated with volatile organic chemicals used as tap water. Recent experience of environmental regulatory agencies indicates that vapor intrusion is the most significant pathway for volatile organic chemicals, that is, it is the exposure pathway that usually drives the risk from long-term (chronic) exposure to this class of chemicals. Therefore, it is the pathway that has the greatest effect on the calculations performed to estimate concentration(s) of volatile chemicals that may be safely left behind after remediation or corrective action. The following exposure pathways are not usually relevant for volatile chemicals: • Incidental ingestion of soil contaminated with volatile organic chemicals. • Dermal contact with soil contaminated with volatile organic chemicals. • Ingestion of food products contaminated with volatile organic chemicals in soil and groundwater. The remainder of the discussion below focuses on the evaluation of the indoor air exposure pathway only. The approach for evaluation of all other exposure pathways associated with volatile organic chemicals is described in other USEPA and DTSC guidance documents (USEPA Risk Assessment Guidance for Superfund, Volume 1 Human Health Evaluation Manual (Part A), 1989; DTSC Supplemental Guidance for Human Health Multimedia Risk Assessments of Hazardous Waste Sites and Permitted Facilities, 1993; USEPA Soil Screening Guidance, 1996). State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 C - 2 Overview of the Human Health Risk Assessment Process The human health risk assessment process for a facility or site has four parts: 1) data collection and evaluation, 2) exposure assessment, 3) toxicity assessment, and 4) risk characterization. In data collection and evaluation, site conditions are characterized, potential chemicals of concern are identified, and the nature and extent of contamination are determined in a site investigation. The exposure assessment builds on the results of the site investigation. The concentrations of the chemicals of concern in environmental media (soil, air, water) are evaluated in the framework of a chosen land use scenario (residential, industrial, recreational, etc.). Exposure pathways that would be associated with that land use are identified, and the exposure (or potential dose) to the chemicals of concern are quantified. Included in exposure assessment is the modeling of chemicals from the point of release to the point of exposure (fate and transport modeling). With respect to the indoor air exposure pathway, fate and transport modeling may be used to simulate the diffusion of a chemical released to soil or present in groundwater (the source) upward as a vapor through soil pores towards the surface and the pressure-driven flow of the vapor from soil through a building foundation and into indoor air (the point of exposure). The efforts of the DTSC in site investigations are primarily in data collection, data evaluation and exposure assessment. Toxicity assessment refers to the identification of a chemical as one that may cause an adverse health effect under certain conditions of exposure and the dose of that chemical necessary to cause that effect. Numeric toxicity criteria have been developed by regulatory agencies for chemicals commonly found at chemical release sites that define the toxicity of the chemical. Two kinds of toxicity criteria are used in human health risk assessments. A reference dose (RfD) or reference concentration in air (RfC) for a chemical is a daily exposure level for a human that will not result in an adverse non-cancer health effect. A cancer slope factor (CSF) or unit risk factor (URF) for a chemical is an expression of the potency of that chemical to cause cancer. The CSF or URF represents the probability (risk) of the chemical to cause cancer after a lifetime of exposure. In risk characterization, the calculated exposure dose and toxicity criteria are brought together to develop an estimate of hazard (referring to non-cancer effects) and of risk (referring to the probability of getting cancer as a result of a lifetime of exposure to the chemical). These equations are given in the Risk Equations section below. Land Use Assumptions The residential home dweller is the default exposure scenario, because the parameters used to define this scenario are usually the most conservative. For example, it is assumed in this scenario that the resident remains at home 24 hours per day and lives in the same home for 30 years. The indoor worker is the most common alternative site-specific exposure scenario. It is assumed in this scenario that the work day is eight hours, and the worker remains at the same job or facility for 25 years. Risk Equations in Indoor Air Inhalation Exposure The equation used to calculate the theoretical excess cancer risk from inhalation exposure to volatile chemicals may be expressed as: State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 C - 3 ar365days/ye x AT URF x EFD x CRisk c building= The equation used to calculate the hazard quotient (HQ) for inhalation exposure to noncarcinogenic volatile chemicals may be expressed as: ar365days/ye x AT 1/RfC x EFD x CQuotient Hazard nc building= Where: Cbuilding = Chemical concentration in the exposure medium of indoor air in micrograms per cubic meter (µg/m3); this value is either determined by fate and transport modeling or is equal to the value measured by indoor air sampling. EFD = Exposure frequency and duration, describing how long and how often exposure occurs, usually calculated using two terms: EF = Exposure frequency in days per year. ED = Exposure duration in years. AT = Period of time over which exposure is averaged in days. ATc = Averaging time for carcinogens, 70 years. ATnc = Averaging time for noncarcinogens, equal to the exposure duration. URF = Unit risk factor, representing the increase in risk per micrograms of chemical inhaled per cubic meter (µg/m3)-1. RfC = Reference concentration, the concentration to which humans may be exposed without risk of adverse health effects during a lifetime, in µg/m3. These equations may be rearranged to calculate the building concentration that would be considered safe by setting a target risk (usually one-in-a-million (10-6) or one-in-a-hundred- thousand (10-5)) and target hazard quotient (always 1.0). A fate and transport model may then be used to calculate the relevant environmental medium concentration that would result in the target building concentration. Using the USEPA Vapor Intrusion Model In the USEPA Vapor Intrusion Model spreadsheets, as modified by the DTSC, environmental media concentrations (groundwater, soil gas) are input into the spreadsheet along with default or site-specific input parameters describing the characteristics of the subsurface (total soil porosity, fraction of organic carbon, soil bulk density, soil water-filled porosity, air permeability, depth to contamination, etc.). The overall objective of the model is to calculate the attenuation factor “alpha” (α), which is the ratio of indoor air concentration to soil gas concentration. The model does this by using soil gas data and simulating the migration of the vapor upwards and into indoor air. If groundwater data are used in the USEPA Vapor Intrusion Model, the model converts the groundwater concentrations to soil vapor concentrations before performing the simulation. The calculated indoor air concentration represents the exposure medium concentration, Cbuilding, in the equations State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 C - 4 above. Finally, the USEPA Vapor Intrusion Model performs the risk calculations to provide the risk and hazard posed by the chemical. A discussion of the fate and transport part of this model is found in Appendix D. Exposure Parameters The exposure parameters recommended by the DTSC for the evaluation of the indoor air pathway are the same as those recommended by the USEPA in various guidance documents (USEPA Risk Assessment Guidance for Superfund (RAGS) (1989); USEPA Soil Screening Guidance (1996); USEPA Exposure Factors Handbook (1997)) and those used by the California Environmental Protection Agency (Cal/EPA) Office of Environmental Health Hazard Assessment (OEHHA) in their development of human exposure-based soil screening numbers (2004). The relevant generic exposure parameters for this pathway assume residential land use and are: EF = Exposure frequency, 350 days per year. ED = Exposure duration, 30 years. ATc = Averaging time for carcinogens, 70 years. ATnc = Averaging time for non-carcinogens, 30 years. Two other exposure parameter values, body weight (70 kg) and contact or intake rate (breathing rate: 20 cubic meters per day) are incorporated into the URF and RfC. These are the default exposure parameters used in the USEPA Vapor Intrusion Model. Site-Specific Exposure Parameters Of all the human exposure parameters, changing the exposure duration (ED) has the greatest effect on calculating the intake of the chemical. In site-specific circumstances, it is possible to decrease the exposure duration with appropriate documentation. For example, in an occupational setting where it is expected that current operations will continue to the foreseeable future, employment records for the facility may be used to estimate a reasonable duration of employment. Toxicity Criteria A unit risk factor (URF, (µg/m3)-1) is the toxicity criterion defining the potency of carcinogenic chemical when inhaled. A chronic reference concentration (RfC, µg/m3) for a chemical is derived from the threshold concentration where no adverse health effects are expected to occur from long-term exposure to that chemical. Numeric toxicity criteria have been developed for specific chemicals by OEHHA and USEPA. The DTSC uses those criteria developed by OEHHA in human health risk assessments. If a criteria value does not exist for a specific chemical, the DTSC uses USEPA values. The DTSC Human and Ecological Risk Division (HERD) version of the USEPA Vapor Intrusion Model contains the toxicity criteria acceptable to the DTSC. These criteria are automatically called-up from the model’s look-up table when the chemical to be evaluated is identified. Occupational Standards Versus Risk-Based Standards Although USEPA and the Occupational Safety and Health Administration (OSHA) have agreed that OSHA Permissible Exposure Limits (PELs) will be used as concentration thresholds in occupational exposures at chemical release facilities, DTSC HERD and State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 C - 5 USEPA regional risk assessors object to this use of OSHA PELs as protective concentration thresholds in the workplace. DTSC notes that OSHA PELs are not intended to protect against “continuous, uninterrupted exposures or other extended work periods” (Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices, American Conference of Governmental Industrial Hygienists, 1994-1995). Furthermore, OSHA PELs are not indices of toxicity and, thus, cannot be assumed to protect all workers. Rather, OSHA PELs assume that the potentially exposed worker has been trained in workplace regulations and is subjected to routine biomedical monitoring, as necessary. This means that office workers at a chemical release facility who have not been so trained, who do not have access to protective gear, and/or are not protected by other environmental controls, may be at risk if only OSHA PELs are invoked as concentration thresholds in their workplace. Therefore, DTSC recommends that the health risk assessment approach as discussed in this guidance be utilized for all land use exposure scenarios, including the indoor worker scenario (see Appendix F for more information). Cumulative Risk Calculations The USEPA Vapor Intrusion Model calculates the risk or hazard posed by a single, specific chemical intruding into indoor air spaces from the subsurface, resulting in exposure by inhaling contaminated indoor air – a single exposure pathway. It is important to remember that a human health risk assessment for a site or facility must include the risks and hazards posed by all chemicals of concern detected and all complete exposure pathways. This is done by first summing the risks and hazards posed by all chemicals via each, separate, complete exposure pathway, then by summing the risks/hazards from all complete exposure pathways. The cumulative risk or hazard for the indoor air exposure pathway is calculated by summing the individual risk/hazard of each evaluated volatile chemical. This may be done one of several ways. In all of the three alternative methods described below, the first thing that must be done is to identify each volatile chemical detected at the site as a carcinogen or a non-carcinogen. All carcinogens are summed separately from the non-carcinogens. Comparing the site soil vapor concentration of a chemical to OEHHA human-exposure- based soil vapor screening number for that chemical Screening numbers have been published by OEHHA for many of the toxic volatile chemicals found at chemical release sites. As described in this guidance, these numbers may be used in the initial human health evaluation of a site. For sites where more than one volatile chemical has been detected, cumulative risks and a hazard index for all the chemicals found are calculated as follows. For sites with more than one non-carcinogenic volatile chemical contaminant, the hazard index is calculated by summing the ratio of the hazard quotient of each chemical. For non- carcinogenic chemical species S1, S2, . . . , Sn with soil vapor concentrations C1, C2, . . . , Cn and OEHHA soil gas screening numbers SN1, SN2, . . . , SNn, the non-carcinogenic hazard index is: Hazard Index = C1/SN1 + C2/SN2 + . . . + Cn/SNn It is vital that the soil vapor screening number used in this Hazard Index calculation has been identified as being based on a reference level for chronic toxic effects other than State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 C - 6 cancer. For sites with more than one carcinogenic chemical contaminant, the cumulative cancer risk is calculated by summing the ratios and multiplying the sum by 10-6. For carcinogenic chemical species S1, S2, . . . , Sn with soil vapor concentrations C1, C2, . . . , Cn and soil gas screening numbers SN1, SN2, . . . , SNn, the cancer risk is calculated using the expression: Risk = [C1/SN1 + C2/SN2 + . . . + Cn/SNn] x 10-6 The soil vapor screening number used in this risk calculation must be based on a carcinogenic potency factor. Comparing the indoor air concentration calculated using the attenuation factors given in Step Five, Preliminary Screening Evaluation, to OEHHA Target Indoor Air Concentrations In the OEHHA document, Human-Exposure-Based Screening Numbers Developed to Aid Estimation of Cleanup Costs for Contaminated Soil (December 2004), a list of target residential indoor air concentrations for specific chemicals is given in an appendix. Once the indoor air concentration for a chemical has been calculated using the method described in Step Five of this guidance document, the hazard index and cumulative risk posed by all volatile organic chemicals found at the site from the indoor air inhalation exposure pathway is calculated in a similar fashion as described above. The hazard index is calculated by summing the ratio of the hazard quotient of each chemical. For non-carcinogenic chemical species S1, S2, . . . , Sn with calculated indoor air concentrations IAC1, IAC2, . . . , IACn and OEHHA target indoor air concentrations TIAC1, TAIC2, . . . , TIACn, the non-carcinogenic hazard index is: Hazard Index = IAC1/TIAC1 + IAC2/TIAC2 + . . . + IACn/TIACn The TIACs used in this Hazard Index calculation must be based on a reference level for chronic toxic effects other than cancer. The cumulative cancer risk is calculated by summing the following ratios and multiplying the sum by 10-6. For carcinogenic chemical species S1, S2, . . . , Sn with calculated indoor air concentrations IAC1, IAC2, . . . , IACn and OEHHA target indoor air concentrations based on carcinogenic potency factors TIAC1, TIAC2, . . , TIACn, the cancer risk is calculated using the expression Risk = [IAC1/TIAC1 + IAC2/TIAC2 + . . . + IACn/TIACn] x 10-6 As stated in the previous section, the target indoor air concentration used in this risk calculation must be based on a carcinogenic potency factor. Adding the risks and hazard quotients calculated using the USEPA Vapor Intrusion Model as modified by the DTSC In those circumstances where the USEPA Vapor Intrusion Model spreadsheet is used to calculate the chemical-specific risk or hazard quotient posed by a chemical intruding into indoor air, the method used to calculate the cumulative risk or hazard posed by all the State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 C - 7 volatile chemicals detected at the site is very simple. The incremental risk calculated for each chemical is simply added together to get the cumulative cancer risk, and the hazard quotient calculated for each chemical is added together to get the hazard index for this exposure pathway. Uncertainties In the fate and transport modeling of chemicals through the environment and the health risk assessment of those chemicals, assumptions must be made since there is never complete information about the physical aspects of a site, and there is no way to accurately predict future exposures and consequent risks from those exposures. Therefore, these assumptions must be reasonably conservative in order to be protective of human health but not so conservative as to be outside of the range of probability. DTSC recommends that all health risk assessments contain an uncertainty section that attempts to define and discuss the major assumptions and uncertainties inherent in the assessment. With respect to the indoor air exposure pathway, some of the uncertainties that should be discussed are discussed below. Uncertainties that could result in a risk or hazard greater than that calculated: • The existence of unidentified preferential pathways in the subsurface that would facilitate the movement of soil vapors into indoor air spaces, such as, naturally occurring geologic faults, the presence of permeable fill material below foundations, openings in the foundation slab made for electrical conduits, plumbing, drainage, space heating, and cooling equipment. • A decrease in ventilation rates in current and future buildings on site that could lead to a buildup of toxic contaminants in indoor air intruding from the subsurface. • The biotransformation of a chemical from a relatively benign compound to a more toxic compound, such as the transformation of numerous precursors to vinyl chloride. Uncertainties that could result in a risk or hazard lower than that calculated: • A reduction in exposure duration of residents and workers over the contaminated subsurface. • A decrease over time in the contaminant mass in the subsurface available for volatilization into soil pore spaces. • The biodegradation of a volatile chemical in soil over time leading to decreasing exposure over time. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 D - 1 APPENDIX D – OVERVIEW OF THE JOHNSON AND ETTINGER MODEL Fate and transport models can assist in evaluating the degradation of indoor air quality due to the intrusion of subsurface volatile contaminants. However, models are not intended to serve as the exclusive approach for evaluating human health risk due to vapor intrusion. When used in combination with site-specific information, the results of modeling will add to the overall weight of evidence used to evaluate the exposure pathway. The Johnson and Ettinger (1991) model (J/E) is one of the most commonly used models for evaluating the indoor air exposure pathway. DTSC has selected the J/E model as the recommended approach to evaluate the vapor intrusion pathway in California. USEPA programmed the J/E model into Microsoft EXCEL™ and added a health risk component that calculates the risk from inhaling the specific chemical at the concentration estimated in indoor air. Examples of the USEPA Vapor Intrusion Model as modified by DTSC can be found on DTSC’s webpage. However, other vapor intrusion models are available and the intent of this Guidance is not to exclude the use of different models to evaluate indoor air quality. The use of any model at a site besides the USEPA Vapor Intrusion Model should be approved by DTSC during the workplan stage prior to use of the model to evaluate risk. The J/E model is a simple, deterministic model, having single-point inputs and outputs. The J/E model is based on the basic principles of contaminant fate and transport, contaminant partitioning between media, and the physical and chemical properties of the contaminants themselves. The model incorporates both diffusion and advection as mechanisms of transport of subsurface vapor into the indoor air environment. Diffusion is the mechanism by which vapor moves from high concentration to low concentration due to a concentration gradient. Advection is the transport mechanism by which vapor moves due to differences in pressure. For the J/E model, diffusion is the dominant mechanism for vapor transport within the vadose zone. Once the vapor enters into the “building zone of influence”, the vapors are swept into the building through foundation cracks by advection due to the indoor – outdoor building pressure differential. The distance of the “building zone of influence” is usually less than a few feet. The J/E model uses the conservation of mass principle and is based on the following assumptions: • Steady-state conditions exist. • An infinite source of contamination exists. • The subsurface is homogeneous. • Air mixing in the building is uniform. • Preferential pathways do not exist. • Biodegradation of vapors does not occur. • Contaminants are homogeneously distributed. • Contaminant vapors enter a building primarily through cracks in the foundation and walls. • Buildings are constructed on slabs or with basements. • Ventilation rates and pressure differences are assumed to remain constant. The J/E model is widely used across the United States to model vapor intrusion. However, the J/E model cannot evaluate preferential migration pathways and fractured bedrock conditions. Each of these conditions has the potential to significantly increase the rate of vapor intrusion beyond what the model would predict. With an understanding of the above- mentioned limitations, the J/E model can allow users to quickly screen sites for vapor intrusion risk. The output of the J/E model is the dimensionless attenuation factor “alpha” State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 D - 2 (α) that represents the ratio of the indoor air concentration to the vapor concentration at a subsurface source. Using the attenuation factor and the appropriate target indoor air concentrations, contaminant concentrations in soil gas and groundwater that are protective of human health can be calculated, and these calculated values can be used as site cleanup goals. The J/E model is most robust under homogeneous site conditions with uniform building construction features. Conversely, the model is weakest under variable conditions. Using a range of potential input parameters, the model can predict a wide range of indoor air impacts spanning over several orders of magnitude. Thus, when using the J/E model for California sites, the input parameters for a given facility must be appropriately conservative and match site-specific conditions. This is especially true for sites with nonbiodegradable chemicals, shallow to moderate depths of contamination, and a high advective potential (Hers et al., 2003). Hence, it is important to understand the sensitivity of the inputs parameters on the results of the model, and DTSC recommends that all vapor intrusion evaluations include a sensitivity analysis. Evaluation of Vapor Intrusion Risk DTSC recommends the use of a two-phased approach in evaluating the vapor intrusion at a facility. A phased approach ensures that simple cases can be evaluated relatively quickly with minimal resources. The first phase of the evaluation utilizes default attenuation factors to quickly quantify the risk for vapor intrusion (Step 5). Conservative assumptions, appropriate for California, were used to generate the default attenuation factors (see Appendix C). If the preliminary screening demonstrates that the risk associated with vapor intrusion is acceptable, no further evaluation for the exposure pathway is warranted. After evaluating the risk with preliminary screening values, the responsible party has numerous options if the site risk is unacceptable. One option is further evaluation of the vapor intrusion risk through a site-specific evaluation (Step 7). A site-specific evaluation builds on a preliminary evaluation and utilizes conditions specific to the site concerning input parameters, land use, and exposure scenarios. The site-specific approach calls for increasingly sophisticated levels of data collection and analysis. Another option is site cleanup. The subsurface of the site can be remediated to the standards determined in the preliminary evaluation. Responsible parties may opt to pursue remediation without further site-specific modeling if the cleanup is time critical or if the volume of subsurface contamination is limited and can be remediated in a straightforward manner. DISCUSSION OF MODELING INPUT PARAMETERS The following input parameters should be used for all site-specific J/E modeling in California: Indoor-Outdoor Pressure Differential (∆P) 4 Pascals Crack-to-Total Area Ratio (η) 0.005 (unitless) Residential Indoor Air Exchange Rate (Eb) 0.5 hr-1 Commercial Indoor Air Exchange Rate (Eb) 1.0 hr-1 The basis of the selection of these input parameters is provided below. DTSC will consider the use of other modeling input parameters if an appropriate technical justification is provided. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 D - 3 Indoor-Outdoor Pressure Differential (∆P) Advective transport of soil vapors into buildings occurs as the result of the depressurization of buildings relative to the pressure in the surrounding soil. This indoor-outdoor pressure differential (∆P), which is referred to as negative pressure, drives the flow of vapors into the building. The soil vapor flows into the building through cracks, gaps, and opening within the foundation. The pressure differential is caused by meteorological, mechanical, and occupant behavior factors. The meteorological factors include indoor-outdoor temperature differences (i.e., ‘stack effect’), wind loading on the building superstructure, and barometric pressure changes. Examples of mechanical and occupant behavioral factors that lead to building depressurization include the operation of exhaust fans, ceiling fans, fireplaces, and furnaces. The potential range of values for indoor-outdoor pressure differential are 0 to 20 Pascals (1 Pa = 10 g/cm-s2) (Loureiro et al., 1990; Eaton and Scott, 1984). Individual values for indoor- outdoor pressure differential have been published as follows: Author Building Effect ∆P values (Pascals) Nazaroff et al., 1985; Put and Meijer, 1989 Wind and stack effects 2 Loureiro et al., 1990; Grimsrud et al., 1983 Wind and heating effects 4 -5 Fischer et al., 1996 Wind effects 3 Lindmark and Rosen,1985 n/a 0 – 2* * Buildings with mechanical ventilation and good insulation may have pressure differentials three times these values. The above information indicates that some degree of negative pressure should be incorporated into any vapor intrusion evaluation. Quantifying the degree of building depressurization is a highly uncertain process. Due to this uncertainty and the inability to estimate the simultaneous interactions of all the depressurization factors, a value for building depressurization of 4 Pascals (40 g/cm-s2) was chosen as a conservative default for California. Crack-to-Total Area Ratio (η) The crack-to-total area ratio (η) is the ratio of the total area of cracks in the foundation and building floor available for vapor flow to the area of the floor. The parameter is also referred to as the “crack factor”. With respect to model sensitivity to crack factor, Johnson (2002) states that the J/E model is not sensitive to the selection of a crack factor for scenarios where advection dominates the movement of soil vapor. However, in scenarios where the intrinsic permeability of the soil is below 1.0E-9 centimeters per second squared, the movement of vapor will be dominated by diffusion and the selection of a crack factor becomes important. Johnson (2002) suggests that reasonable crack factor range from 0.0005 to 0.005. The American Society of Testing and Materials (1995) suggested a default value of 0.01 for the crack-to-total area ratio in their standard for risk-based corrective action. USEPA (2002b) used a crack factor of 0.0002 for houses with basements and 0.0038 for slab-on-grade houses. A value for crack factor of 0.005 was selected as a conservative default for California. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 D - 4 Indoor Air Exchange Rate (Eb) Indoor air exchange is the principal mechanism for diluting indoor air contamination. The air exchange rate is defined as the number of times that the total volume of air within a building is replaced by external air, and the rate is usually expressed in terms of air exchanges per hour (i.e., hour-1). Air within a building is exchanged through three processes; a) mechanical or forced ventilation, b) natural ventilation, and 3) infiltration. Mechanical or forced ventilation systems include the operation of exhaust fans, ceiling fans, fireplaces, and furnaces. Natural ventilation relates to occupant behaviors and activities like the opening and closing of doors and windows. Infiltration is defined as the uncontrolled airflow through foundation cracks, gaps, and opening. The infiltration of air is caused by indoor-outdoor temperature differences, wind loading on the building superstructure, and barometric pressure changes. The scientific literature indicates that residential air exchange rates can range from 0.2 to 2.0 air exchanges per hour. Rates vary as a function of calendar season, building construction, building energy efficiency, and climatic conditions. Two nationwide studies of residential air exchange rates included data from California. Versar (1990) compiled about 100 separate field research projects by various organizations, which involved both random sampling and judgmental sampling. Most of the studies involved the use of perfluorocarbon (PFT) tracer gas to measure time-averaged air exchange rates. The PFT technique utilizes miniature permeation tubes as tracer emitters and passive samplers to collect the tracers, which were analyzed by gas chromatography. Murray and Burmaster (1995) also analyzed the PFT database and summarized distributions of exchange rates in subsets defined by climate and season. In this data evaluation, Murray and Burmaster lumped California data with other climatically appropriate states. A comprehensive review of residential indoor air exchange rates can be found in the Exposure Factors Handbook by USEPA (1997). Air exchange rates for California are summarized below as taken from USEPA (1997). For residential buildings in California, a value of 0.50 air exchanges per hour should be used as a conservative default value. This value is approximately the 25th percentile of houses in California. Summary of Air Exchange Rates for California Percentiles Project Code Month(s) 10th 25th 50th 90th Number of Measurements ADM May - Jul 0.29 0.36 0.48 1.75 29 BSG Jan, Aug - Dec 0.21 0.30 0.40 0.90 40 RT11 Feb 0.38 0.48 0.78 1.52 45 RT12 Jul 0.79 1.18 2.31 5.89 41 SOCAL1 Mar 0.29 0.44 0.66 1.43 551 SOCAL2 Jul 0.35 0.59 1.08 3.11 408 SOCAL3 Jan 0.26 0.37 0.48 1.11 330 weighted average 0.31 0.48 0.78 1.95 Note: 1) Units are air exchange rates per hour. 2) Data taken from USEPA (1997). For commercial buildings, a default of 1.0 air exchange rate per hour should be used. This number is based upon the minimal ventilation requirements pursuant to the 2001 Energy Efficiency Standards for Nonresidential Buildings (California Energy Commission, 2001). State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 D - 5 The minimum ventilation requirement is 0.15 cubic feet per minute per square foot of building space. For a single story commercial building, this equates to approximately 1.0 air exchanges per hour. Average Soil and Groundwater Temperature For vapor migration, the average soil and groundwater temperature is used to correct Henry’s law constant to the appropriate subsurface temperature. When possible, the site- specific subsurface temperatures should be used when making the correction to Henry’s law constant. During the routine sampling of monitoring wells, temperature is collected as a stabilization parameter during well purging. This temperature value can be used to make the Henry’s law constant correction if monitoring wells exist at the site. If no monitoring wells exist at the site, the groundwater temperatures as collected at nearby sites can be used when the wells are screened within the water table. In cases where no subsurface temperature data are available, the subsurface temperature can be inferred from the isothermal contour lines shown in the map below. The map is from USEPA (1995) and shows the average temperature in shallow groundwater for California. Typically, in California, shallow groundwater temperatures range from 11 °C (Modoc Plateau) to 24 °C (Imperial Valley). Also, the subsurface temperature can be determined from the mean air temperature using the procedures from Toy et al. (1978). Figure A-1: Groundwater Temperatures for California State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 D - 6 REFERENCES American Society for Testing and Materials. 1995. Standard Guide for Risk-Based Corrective Action Applied at Petroleum Release Sites. ASTM E1739-95, Philadelphia, PA. California Energy Commission. 2001. Manual for Compliance with the 2001 Energy Efficiency Standards (for Nonresidential Buildings, High-Rise Residential Buildings, and Hotels/Motels). Document No. P400-01-032. August 2001. Eaton, R. S., and A. G. Scott. 1984. Understanding Radon Transport into Houses. Radiation Protection Dosimetry, v. 7, p. 251 - 253. Fischer, M. L., A. J. Bentley, K. A. Dunkin, A. T. Hodgson, W. W. Nazaroff, R. G. Sextro, and J. M. Daisey. 1996. Factors Affecting Indoor Air Concentrations of Volatile Organic Compounds at a Site of Subsurface Gasoline Contamination. Environmental Science and Technology, v. 30, n. 10, p. 2948 - 2957. Grimsrud, D. T., M. H. Sherman, and R. C. Sonderegger. 1983. Calculating Infiltration: Implications for a Construction Quality Standard. In: Proceedings of the American Society of Heating, Refrigeration, and Air Conditioning Engineers Conference, Thermal Performance of Exterior Envelopes of Buildings II. ASHRAE SP38, p. 422 - 452. Atlanta, GA. Hers, I., R. Zapf-Gilje, P. C. Johnson, and L. Lu. 2003. Evaluation of the Johnson and Ettinger Model for Prediction of Indoor Air Quality. Ground Water Monitoring and Remediation, v. 23, n. 1, p. 62 – 76. Johnson, P. C., and R. A. Ettinger. 1991. Heuristic Model for Predicting the Intrusion of Contaminant Vapors into Buildings. Environmental Science and Technology, v. 25, n. 8, p. 1445 – 1452. Johnson, P. C. 2002. Identification of Critical Parameters for the Johnson and Ettinger (1991) Vapor Intrusion Model. API Bulletin No. 17. American Petroleum Institute. Washington, DC. May 2002. Lindmark, A., and B. Rosen. 1985. Radon in Soil Gas-Exhalation Tests, In Situ Measurements. The Science of the Total Environment, v. 45, p. 397 - 404. Loureiro, C. O., L. M. Abriola, J. E. Martin, and R. G. Sextro. 1990. Three-Dimensional Simulation of Radon Transport into Houses with Basements Under Constant Negative Pressure. Environmental Science and Technology, v. 24, p. 1338 - 1348. Murray, D. M., and D. E. Burmaster. 1995. Residential Air Exchange Rates in the United States: Empirical and Estimated Parametric Distribution by Season and Climatic Region. Risk Analysis, v. 15, n. 4, p. 459 – 465. Nazaroff, W. W., H. Feustel, A. V. Nero, K. L. Revan, D. T. Grimsrud, M. A. Essling, and R. E. Toohey. 1985. Radon Transport into a Detached One-Story House with a Basement. Atmospheric Environment, v.19, n. 1, p. 31 - 46. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 D - 7 Put, L. W., and R. J. Meijer. 1989. Luchtdrukverschillen in en Rond Een Woning; Implicaties Voor het Transport van Radon. Kernfysisch Versneller Instituut, Groningen University, The Netherlands. Toy, T. J., A. J. Kuhaida, Jr., and B. E. Munson. 1978. The Prediction of Mean Monthly Soil Temperature from Mean Monthly Air Temperature. Soil Science, v. 126, p. 181-189. United States Environmental Protection Agency. 1995. Review of Mathematical Modeling for Evaluating Soil Vapor Extraction Systems. Office of Research and Development, Washington, D.C. Document No. EPA/540/R-95-513. March 1995. United States Environmental Protection Agency. 1997. Exposure Factors Handbook. Office of Research and Development, National Center for Environmental Assessment, Washington D. C. Publication EPA/600/P-95/002Fa. August 1997. United States Environmental Protection Agency. 2002. Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance). Office of Solid Waste and Emergency Response. November 29, 2002. Versar. 1990. Database of Perfluorocarbon Tracer (PFT) Ventilation Measurements: Description and User's Manual. United States Environmental Protection Agency Contract No. 68-02-4254, Task No. 39, Washington, D.C. United States Environmental Protection Agency, Office of Toxic Substances. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 E - 1 APPENDIX E - SOIL GAS CONCENTRATIONS FROM SOIL MATRIX ANALYTICAL RESULTS When it is not possible to collect soil gas samples at a site, the vapor intrusion risk should be evaluated with soil matrix sample data as collected by USEPA Method 5035A. The associated soil gas concentration from the soil matrix data should be determined using the following partitioning calculation (Feenstra et al., 1991) and associated default parameters. )θ H ρfk (θ ρ C HC asococw ssoilgas++= where, Input Parameter Units Default Value Basis for Default Value Cgas Soil gas concentration g/cm3 Calculated - Csoil Soil matrix concentration g/g Measured at site - θw Soil volumetric water content cm3/cm3 0.15 θa Soil volumetric air content cm3/cm3 0.28 ρs Soil bulk density g/cm3 1.5 Default for an unclassified soil foc Soil fraction organic carbon g/g 0.006 USEPA (2004) H Henry’s Law constant unitless Chemical specific - koc Carbon-water sorption coefficient cm3/g Chemical specific - g = grams cm3 = cubic centimeters The above equation assumes equilibrium conditions exist in the subsurface that allow for the full partitioning of contaminants into their respective phases. Hence, the above equation should only be used with a full understanding of these potential limitations. The maximum soil gas concentration, as determined from the soil matrix sampling, should be used for preliminary vapor intrusion evaluations pursuant to Step 5. For site-specific evaluations pursuant to Step 7, the soil gas contaminant source for the vapor intrusion modeling, as determined from the soil matrix sampling, can be statistically approximated if the sample collection is of sufficient density. REFERENCES Feenstra, S., D. M. Mackay, and J. A. Cherry. 1991. A Method for Assessing Residual NAPL Based on Organic Chemical Concentrations in Soil Samples. Ground Water Monitoring and Remediation, v. 11, n. 2, p. 128-136. United States Environmental Protection Agency. 2004. Region 9 Preliminary Remediation Goals (PRGs). USEPA Region IX Solid and Hazardous Waste Program. October 2004. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 F - 1 APPENDIX F – USE OF PERMISSIBLE EXPOSURE LIMITS Use of Occupational Safety and Health Administration (OSHA) Standards The OSHA Permissible Exposure Limits (PELs) are not an appropriate standard for evaluating the risk associated with vapor intrusion to indoor air in California. Pursuant to the California Health and Safety Code, Sections 25150, 25187, 25200.10, and 25356, chemical releases in California should be characterized and mitigated based upon the risk to human and ecological receptors. Hence, for vapor intrusion sites, potential adverse effects to humans should be evaluated in terms of acceptable exposure based upon risk rather than upon comparison to OSHA PEL endpoints. For sites in California, regardless of whether the exposure scenario is residential, commercial, or industrial, OSHA PELs should not be used as exposure endpoints. DTSC regulates chemicals in the subsurface and any human exposure derived from the associated contaminant migration, and OSHA regulates workspace and any associated exposure derived from an industrial process. The one exception where OSHA PEL endpoints may be considered is for operating Resource Conservation and Recovery Act (RCRA) facilities pursuant to USEPA’s Environmental Indicators Program discussed below. OSHA regulates exposure to chemicals in an industrial setting. OSHA regulations prescribe controls and monitoring of the workplace environment to lessen employee exposure to vapors and gases. For employees working in an environment where they may be exposed to vapors and gases that exceed the PELs, training, medical surveillance, personnel monitoring, exposure information, and respiratory protection must be available. Those workplaces that handle volatile materials must control exposure to employees, which is typically done with ventilation systems, process enclosures, work practices, and personal protection equipment. OSHA requires that employees have access to Material Safety Data Sheets (MSDSs) and that employees are trained to recognize hazardous conditions. Hence, workers subject to potential exposure to gases and vapors by the nature of their working environment are regulated under OSHA. These workplaces are usually commercial and industrial settings where hazardous chemicals are handled inside a building as part of a commercial or industrial process. Employees working with a commercial or industrial process that involves hazardous gases or vapors usually work in these conditions voluntarily, are aware of the potential risk of exposure, and have implicitly accepted exposure as an occupational hazard. For gases and vapors, the PEL is the maximum concentration of a chemical in the air that a worker may be exposed to without respiratory protection (California Code of Regulations, Title 8, section 5155). Exposure to PELs is assumed to occur to healthy workers. OSHA did not envision that children, the elderly, or unhealthy adults would be exposed to PEL concentrations. Therefore, OSHA PEL endpoints are not an appropriate health-protective standard for evaluating the risk associated with vapor intrusion to indoor air in California. At sites subject to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), cleanup levels are generally determined either by Applicable or Relevant and Appropriate Requirements (ARARs) or the risk assessment process. OSHA standards are not ARARs under CERCLA statute and regulations. Therefore, OSHA standards should not be applied to CERCLA cleanups. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 F - 2 USEPA Environmental Indicators Program The use of OSHA PELs as an endpoint for exposure due to the vapor intrusion pathway can only be done in one situation within California. OSHA PELs can be used to evaluate RCRA sites subject to the Government Performance and Results Act (GPRA) of 1993. Under GPRA, USEPA is required to prepare strategic plans and associated timeframes for controlling human exposure and contaminant migration in groundwater at RCRA sites. The Environmental Indicators (EI) Program is USEPA’s method of tracking progress for attainment of the GPRA goals. USEPA measures the ability of RCRA facilities to control human exposure to contaminated environmental media, including exposure to contaminated indoor air due to vapor intrusion. As an interim approach for evaluating human exposure due to vapor intrusion into buildings, USEPA allows the use of OSHA PELs at operating RCRA sites as a way to evaluate progress on corrective action activities (USEPA, 2003a). The OSHA PELs are used only at operating RCRA sites as an interim measure to evaluate buildings that house a commercial or industrial process. These buildings must house a process that involves the use of chemicals that are similar to the chemicals subject to vapor intrusion due to prior releases to the environment. Additionally, the workers in these buildings must be subject to Occupational Safety and Health Standards pursuant to Title 29, Code of Federal Regulations. For final remedies at RCRA corrective action sites, risk-based standards are used rather than OSHA PEL endpoints. REFERENCES United States Environmental Protection Agency. 2003a. Vapor Intrusion and RCRA Corrective Action (CA); Environmental Indicators (EI) Fact Sheet. Office of Emergency and Remedial Response. June 17, 2003. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 G - 1 APPENDIX G - SOIL GAS SAMPLING DIRECTLY UNDER BUILDING FOUNDATIONS (SUBSLAB SAMPLING) For sites that fail a preliminary evaluation pursuant to Step 5, a site-specific evaluation of vapor intrusion can be done, which may include the sampling of soil gas beneath a building’s foundation. The number and locations of subslab samples should be determined based on information collected during the building survey, an understanding of the building foundation, and the results from nearby soil gas sampling. At least two subslab samples should be taken at a minimum, with one sample taken in the center of the building’s foundation, if possible. The subslab data will determine if vapors are collecting directly under the building’s foundation and will demonstrate which contaminants potentially represent a threat to human health. If a building is determined to have a vapor barrier and/or a tension slab, special care should be given when hand-drilling through the concrete slab. In particular, for a tension foundation slab, the tension cables within the slab should be located prior to drilling either through visual observation or through remote-sensing with either a metal detector or ground penetrating radar. The cutting of a tension cable within a slab during drilling could disrupt the integrity of the slab and potentially cause injury to the field crew. When evaluating subslab soil gas concentrations for a building, DTSC recommends that permanent sampling points be installed so that repeated sampling can be conducted, as necessary, to evaluate seasonal or temporal variations. The following guidelines for subslab testing are derived, with modifications, from the state of Massachusetts’ Indoor Air Sampling and Evaluation Guide, WSC Policy #02-430 (Massachusetts Department of Environmental Protection, 2002). 1) After removal of the floor covering, small-diameter holes should be drilled through the concrete of the foundation slab. Typically, holes are 1.0 to 1.25 inches in diameter. Either an electric hand drill or concrete corer is used to drill the holes. All subslab utilities should be located and clearly marked on the slab prior to drilling. Subslab holes should be advanced 3 to 4 inches into the subslab material. The sampling probe should be constructed with the following specifications: • Vapor probes are typically constructed of 1/8 inch or 1/4 inch diameter brass or stainless steel pipe, with a permeable probe tip. A Teflon™ sealing disk should be placed between the probe tip and the blank pipe. • Bentonite chips should be used to fill the borehole annular space between the probe pipe and subslab gravel from the Teflon sealing disk to the base of the concrete foundation. Sufficient water should be added to hydrate the bentonite to insure proper sealing, and care should be used in placement of the bentonite to prevent post-emplacement expansion which might compromise both the probe and cement seal. If needed, the vapor probe tip can be covered with sand. • The probe pipe should be tightly sealed to the foundation slab with quick-setting contaminant-free Portland cement. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 G - 2 • Each probe should be constructed with a recessed threaded cap with a brass or stainless steel threaded fitting or compression fitting so the probe completion is flush with the foundation slab to reduce the tripping hazard. • At least 30 minutes of time should elapse following installation of a probe to allow the cement to cure and allow for the subsurface conditions to equilibrate prior to sampling. An example of a sampling probe is shown in the attached schematic diagram. 2) The collection of subslab samples should follow the procedures in Cal-EPA (2003), which recommends purge volume testing, leak testing, and the use of surface seals to insure sample integrity, as appropriate for field conditions. Samples should be collected in gas-tight, opaque/dark containers so that light-sensitive or halogenated VOCs will not degrade. The use of Tedlar bags for collection of soil gas samples is not recommended. If a SummaTM canister is used, a flow regulator should be placed between the probe and the canister to ensure that the canister is filled at the appropriate flow rate. Flow rates should not exceed 200 ml/min. Care should be taken during sampling to avoid sample break-through from the surface of the slab. 3) Subslab soil gas sampling should be performed using analytical methods in Cal-EPA (2003). These methods include USEPA Methods 8260B, 8021B, and 8015B. Other methods that may be used include USEPA Methods TO-14A, TO-15, and other methods that meet the site-specific data quality objectives and the analytical method detection limits for risk determination. 4) A sufficient number of subslab sampling events should be conducted to account for seasonal and temporal transience. Therefore, a minimum of two subslab sampling events are warranted before a final risk determination is made. 5) Upon completion of all the sampling, the foundation probes should be properly decommissioned. The probe tip, probe piping, bentonite, and grout should be removed by redrilling. The borehole should be filled with grout and concrete patch material. Surface restoration should include a follow-up visit for final sanding and finish work to restore the floor slab to its original condition. The use of passive soil gas methods for subslab sampling are not recommended for risk determination. Passive soil gas sampling should only be considered to identify subsurface contaminants, preferential pathways for vapor movement, and to reduce uncertainty caused by temporal variations. REFERENCES California Environmental Protection Agency. 2003. Advisory – Active Soil Gas Investigation. Jointly issued by the Regional Water Quality Control Board, Los Angeles Region and the Department of Toxic Substances Control. January 28, 2003. [www.dtsc.ca.gov/Publications Forms/index.html] Massachusetts Department of Environmental Protection. April 2002. Indoor Air Sampling and Evaluation Guide, WSC Policy #02-430. Massachusetts Department of Environmental Protection. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 G - 3 SCHEMATIC DIAGRAM OF A SUBSLAB SAMPLING PROBE Recessed Fitting Foundation Surface Foundation Surface CONCRETE SLAB SUBSLAB FILL NATIVE SOIL Thickness May Vary (approximately 10 – inches) Thickness May Vary (approximately 5 - inches) 1 in. 2 to 3 in. Quick-Set Cement Grout Metal Tubing (1/4 – in.) Bentonite Seal Teflon Separator Vapor Probe Tip State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 H - 1 APPENDIX H – SOIL LABORATORY MEASUREMENTS For site-specific evaluations of vapor intrusion, determination of the physical properties of the vadose zone may be needed. If so, soil samples should be collected for the evaluation of the physical character of the subsurface during site characterization. Soil can be submitted to a laboratory for the measurement of bulk density, grain density, total porosity, moisture content, fraction organic carbon, and grain size. The recommended geotechnical laboratory methods are: Soil Bulk Density ASTM D2937. Grain Density ASTM D854. Total Porosity Calculate from the soil bulk density and the grain density. Soil Moisture Content ASTM D2216. Fraction Organic Carbon Walkley-Black method (Nelson and Sommers, 1992). Grain Size ASTM D422. REFERENCES Nelson, D. W., and L. E. Sommers. 1982. Total Carbon, Organic Carbon, and Organic Matter. In: A. L. Page et al. (editors), Methods of Soil Analysis: Part 2 Chemical and Microbiological Properties. ASA [American Society of Agronomy, Inc.] Monograph Number 9, p. 539 – 579. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 I - 1 APPENDIX I – IN-SITU SOIL AIR PERMEABILITY MEASUREMENTS For site-specific evaluations of vapor intrusion, determination of the air permeability of the shallow soil may be needed. In these cases, air permeability measurements can be conducted using the same equipment that is used to collect soil gas samples. Permeabilities are determined by measuring the gas pressure in a vapor probe or well bore as a metered flow of air is passed through the probe or well into the soil. The measurement of in-situ air permeability should be conducted at depths of five feet or less, which is the approximate depth of the building-driven advective movement of vapors in the USEPA Vapor Intrusion Model. However, these air injection tests should only be conducted after soil gas samples have been obtained because the injected gas will distort subsurface concentration measurements. The following equation can be used to determine in-situ air permeability. The equation has been adapted from an analytical expression by Hvorslev (1951) and Hsieh et al. (1983) for the spatial distribution of steady-state water pressure around an injection interval. Derivation of the equation can be found in Bassett et al. (1994) and field application of the equation can be found in Guzman (1995). The validity of the method is further discussed in Illman and Neuman (2000) and Vesselinov and Neuman (2001). The equation assumes that, during each relatively stable period of air injection, air is the only mobile phase within the soil near the test interval and is controlled by a steady-state pressure field with prolate spheroidal symmetry. Such symmetry implies that the soil forms a uniform, isotropic porous continuum. The equation is: ()()sc sc 2 o 2 wsc T ZTp pp L r /L ln µQk −=π where, k = air permeability (m2) Qsc = volumetric air flow rate at standard conditions (m3/s) µ = dynamic viscosity of air at standard conditions (1.81 x 10-5 pascal-s) ln = natural logarithm operator L = length of the test interval (m) rw = borehole radius (m) T = air temperature in the test interval (° Kelvin) psc = air pressure at standard conditions (101,300 pascals) Z = air compressibility factor (assume 1.0 [unitless]) π = pi (3.1416) p = air pressure in the injection interval (pascals) po = ambient air pressure during injection (pascals) Tsc = temperature at standard conditions (273° Kelvin) After obtaining a soil gas sample from a borehole, air is injected into the soil probe or well and the pressure and the flow rate of the air are measured at the surface. To conduct the permeability measurements, a cylinder of compressed air can be used as an injection source, along with a flow meter with a range of 5 to 500 cubic centimeters per minute, and a differential pressure gauge with a range of 0 to 125 pascals. To obtain differential pressure State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 I - 2 measurements over the required range, multiple pressure gauges may be needed, because a single gauge will not yield the required measurement range. The following guidance should be considered when collecting and evaluating in-situ air permeability data: • The injection test should continue until steady-state pressure occurs. The occurrence of steady-state pressure is defined as less than a 50 pascals pressure change within 30 minutes. The test should be terminated after 4 hours if pressure stabilization is not obtained. • During the first hour of the test, injection pressure, flow rate, injection temperature, and barometric pressure should be measured at five minute intervals, or as appropriate. After the first hour, data can be collected less frequently but at a minimum interval of 30 minutes. • The air permeability should be calculated with the data obtained during steady-state conditions. • The diameter on the probe tip used for air injection should be measured to within ± 0.01 inches before insertion into the soil and then remeasured upon retrieval from the subsurface to verify no probe diameter distortion occurred during installation. • The above equation is based on the assumption that the flow of injection air is predominantly radial, which is assumed to occur when L/rw is greater than 5 (Bassett et al., 1994). Hence, this ratio of greater than 5 must occur during all air permeability testing. Otherwise, the above is equation cannot be used to calculate air permeability and an alternate method within Bassett et al. (1994) should be followed. • The air compressibility factor in the above equation indicates the extent which the injection air behaves as an ideal gas. The assumption that the air compressibility factor is 1.0 assumes the injected gas behaves as an ideal gas. If site conditions indicate non- ideal gas behavior, the above equation should not be used to determine in-situ air permeability. The use of a single small diameter probe may systematically underestimate the in-situ air permeability due to the measurement length scale (Garbesi et al., 1996; Garbesi et al., 1999). Thus, when possible, numerous air permeabiity measurements should be conducted as a means to evaluate the underprediction. REFERENCES Bassett, R. L., S. P. Neuman, T. C. Rasmussen, A. Guzman, G. R. Davidson, and C. F. Lohrstorfer. 1994. Validation Studies for Assessing Unsaturated Flow and Transport through Fractured Rock. U. S. Nuclear Regulatory Commission, NUREG/CR-6203. Garbesi, K., R. G. Sextro, A. L. Robinson, J. D. Wooley, and J. A. Owens. 1996. Scale Dependence of Soil Permeability to Air: Measurement Method and Field Investigation. Water Resources Research, v. 32, p. 547 - 560. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 I - 3 Garbesi, K., A. L. Robinson, R. G. Sextro, and W. W. Nazaroff. 1999. Radon Entry into Houses: The Importance of Scale-Dependent Permeability. Health Physics, n. 77, p. 183 - 191. Guzman, A. G., A. M. Geddis, M. J. Henrich, C. F. Lohrstorfer, and S. P. Neuman. 1995. Summary of Air Permeability Data From Single-Hole Injection Tests in Unsaturated Fractured Tuffs at the Apache Leap Research Site: Results of the Steady-State Test Interpretation. U. S. Nuclear Regulatory Commission, NUREG/CR-6360. Hsieh, P. A., S. P. Neuman, and E. S. Simpson. 1983. Pressure Testing of Fractured Rocks: A Methodology Employing Three-Dimensional Cross-Hole Tests. U. S. Nuclear Regulatory Commission, NUREG/CR-3213. Hvorslev, M. J. 1951. Time Lag and Soil Permeability in Groundwater Observations. Bulletin 36, U. S. Corps of Engineers, Water Ways Experimental Station, Vicksburg, Michigan. Illman, W. A., and S. P. Neuman. 2000. Type-Curve Interpretation of Multirate Single-Hole Pneumatic Injection Tests in Unsaturated Fractured Rock. Groundwater, v. 38, n. 6, p. 899 – 911. Vesselinov, V., and S. P. Neuman. 2001. Numerical Inverse Interpretation of Single-Hole Pneumatic Tests in Unsaturated Fractured Tuff. Groundwater, v. 39, n. 5, p. 685 – 695. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 J - 1 APPENDIX J – EXAMPLE ACCESS AGREEMENT AUTHORIZATION AND RELEASE I hereby authorize the California Department of Toxic Substances Control and its authorized agents to obtain soil, soil gas, or groundwater samples from my property in the (NAME OF CITY, NAME OF COUNTY), California, for the purpose of characterizing the extent of (SPECIFY THE CHEMICAL(S) TO BE COLLECTED) in the subsurface. The sampling will be performed between the hours of ____ and _____. I understand that persons entitled to access by this Authorization and Release include the Department of Toxic Substances Control, its officers, agents, employees, contractors, and any other person authorized by the Department of Toxic Substances Control, to perform the above activities. I understand that such sampling may involve disturbance of the soil, lawn and vegetation. Therefore, I should advise the Department of Toxic Substances Control agents of the location of sprinkler systems, pipes, drains, etc. The Department of Toxic Substances Control will use reasonable effort to return the property to its condition prior to sampling. I agree to hold harmless the agents of the Department of Toxic Substances Control for any and all damages resulting from the sampling. I understand that the Department of Toxic Substances Control will not be providing a duplicate sample, but will make available to me the analytical results of all sampling activities. _______________________________ ______________________________ Name of Resident Telephone Number _______________________________ _____________________________ Resident Address City / State / Zip Code _______________________________ _____________________________ Property Owner Signature Date State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 K - 1 APPENDIX K - BUILDING SURVEY FORM This form must be completed for each building involved in an indoor air investigation. Preparer’s name __________________________________ Date prepared _______________ Preparer’s affiliation ___________________________________________________________ Telephone number _________________________________ 1. OCCUPANT Name _________________________________________ Address _______________________________________ _______________________________________ City __________________________________________ Home telephone number __________________________ Office telephone number __________________________ 2. OWNER OR LANDLORD Name _________________________________________ (If different than occupant) Address _______________________________________ _______________________________________ Telephone number _______________________________ A. Type of Building Construction Type (circle appropriate responses): Single Family Multiple Dwelling Commercial Ranch Two-family Raised Ranch Duplex Split Level Office Colonial Warehouse Mobile Home Strip Mall Apartment Building: Number of Units __________________________ Other _____________________________________________________ Building Age _________ Number of stories _______________________________ Area of the Building (square feet) __________________________________ Is the building insulated? yes / no How sealed is the building?________________________ Number of elevators in the building _______________________________________________ State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 K - 2 Condition of the elevator pits (sealed, open earth, etc.) ________________________________ General description of building construction materials _________________________________ ____________________________________________________________________________ B. Foundation Characteristics (circle all that apply) 1. Full basement, crawlspace, slab on grade, other _________ 2. Basement floor description: concrete, dirt, wood, other __________ a. The basement is: wet, damp, dry _______ b. Sump present? yes / no _____Water in sump? yes / no ____ c. The basement is: finished, unfinished _______________ d. Is the basement sealed? Provide a description _________________________ ________________________________________________________________ 3. Concrete floor description: unsealed, painted, covered; with __________ 4. Foundation walls: poured concrete, block, stone, wood, other _________ 5. Identify all potential soil gas entry points and their size (e.g., cracks, voids, pipes, utility ports, sumps, drain holes, etc.). Include these points on the building diagram. C. Heating, Ventilation, and Air Conditioning (circle all that apply) 1. The type of heating system(s): Hot Air Circulation Heat Pump Hot Water Radiation Unvented Kerosene Heater Steam Radiation Wood Stove Electric Baseboard Other (specify) _______________________________ 2. The type of fuel used: Natural Gas, Fuel Oil, Electric, Wood, Coal, Solar Other (specify) __________________________________________________________ 3. Location of heating system: ________________________________________________ 4. Is there air-conditioning? yes / no Central Air or Window Units? State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 K - 3 Specify the location ______________________________________________________ 5. Are there air distribution ducts present? yes / no 6. Describe the supply and cold air return duct work including whether there is a cold air return and comment on the tightness of duct joints. ______________________________________________________________________ 7. Is there a whole house fan? yes / no _____________ What is the rated size of the fan? _______________ 8. Temperature settings inside during sampling. Note day and night temperatures. a. Daytime temperature(s) ______ b. Nighttime temperature(s) _____ (Note times if system cycles during non-occupied hours during the day) 9. Estimate the average time doors and windows are open to allow fresh outside air into the building. Note rooms that frequently have open windows or doors. ______________________________________________________________________ D. Potential Indoor Sources of Pollution 1. Is the laundry room located inside the home? yes / no 2. Has the house ever had a fire? yes / no 2. Is there an attached garage? yes / no 3. Is a vehicle normally parked in the garage? yes / no 4. Is there a kerosene heater present? yes / no 5. Is there a workshop, hobby or craft area in the residence? yes / no 6. An inventory of all products used or stored in the home should be performed. Any products that contain volatile organic compounds or chemicals similar to the target compounds should be listed. The attached product inventory form should be used for this purpose. 7. Is there a kitchen exhaust fan? yes / no Where is it vented? ___________________ 8. Is the stove gas or electric? __________ Is the oven gas or electric? ___________ 9. Is there an automatic dishwasher? yes / no 10. Is smoking allowed in the building? yes / no 11. Has the house ever been fumigated or sprayed for pests? If yes, give date, type and location of treatment. ______________________________________________________________________ State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 K - 4 E. Water and Sewage (Circle the appropriate response) Source of Water Public Water Drilled Well Driven Well Dug Well Other (Specify) _____________ Water Well Specifications Well Diameter __________________ Grouted or Ungrouted _________________ Well Depth _____________________ Type of Storage Tank _________________ Depth to Bedrock ________________ Size of Storage Tank __________________ Feet of Casing _________________ _ Describe type(s) of Treatment ___________ Water Quality Taste and/or odor problems with water? yes / no If so, describe ____________________ Is the water chlorinated, brominated, or ozonated? yes / no ______ How long has the taste and/or odor problem been present? __________________________ Sewage Disposal: Public Sewer Septic Tank Leach Field Other (Specify) __________ Distance from well to septic system ________ Type of septic tank additives _____________ F. Plan View Sketch each floor and if applicable, indicate air sampling locations, possible indoor air pollution sources, preferential pathways and field instrument readings. G. Potential Outdoor Sources of Pollution Draw a diagram of the area surrounding the building being sampled. If applicable, provide information on the spill locations (if known), potential air contamination sources (industries, service stations, repair shops, retail shops, landfills, etc.), outdoor air sampling locations, and field instrument readings. Also, on the diagram, indicate barometric pressure, weather conditions, ambient and indoor temperatures, compass direction, wind direction and speed during sampling, the locations of the water wells, septic systems, and utility corridors if applicable, and a statement to help locate the site on a topographical map. State of California DTSC / Cal - EPA Vapor Intrusion Guidance Document – Final Interim December 15, 2004 L - 1 APPENDIX L – HOUSEHOLD PRODUCTS INVENTORY FORM Occupant of Building ___________________________________________________________ Address _____________________________________________________________________ City ________________________________________________________________________ Field Investigator _________________________________ Date _______________________ Product Description (commercial name, dispenser type, container size, manufacturer, etc.) Volatile Ingredients in the Product Field Instrument Reading Comments: ____________________________________________________________________________ ____________________________________________________________________________ Appendix D Traffic Impact Analysis Update TRAFFIC IMPACT ANALYSIS TEMECULA HOSPITAL Temecula, California October 30, 2007 Prepared for: City of Temecula 43200 Business Park Drive Temecula, California 92589-9033 LLG Ref. 3-07-1752 Prepared by: Under the Supervision of: Narasimha Prasad John Boarman, P. E. Senior Transportation Engineer Principal LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc i TABLE OF CONTENTS SECTION PAGE 1.0 Introduction................................................................................................................................ 1 2.0 Project Description.................................................................................................................... 2 2.1 Project Location.................................................................................................................. 2 2.2 Project Description.............................................................................................................. 2 2.3 Project Access..................................................................................................................... 2 3.0 Existing Conditions.................................................................................................................... 3 3.1 Existing Street Network...................................................................................................... 3 3.2 Existing Traffic Volumes....................................................................................................4 3.2.1 Peak Hour Intersection Volume Counts ................................................................. 4 3.2.2 Segment Counts...................................................................................................... 4 4.0 Analysis Approach and Methodology...................................................................................... 6 4.1 Analysis Approach.............................................................................................................. 6 4.2 Analysis Methodology........................................................................................................6 4.2.1 Signalized Intersections.......................................................................................... 6 4.2.2 Street Segments....................................................................................................... 7 5.0 Significance Criteria.................................................................................................................. 9 6.0 Analysis of Existing Conditions.............................................................................................. 10 6.1 Peak Hour Intersection Levels of Service......................................................................... 10 6.2 Daily Street Segment Levels of Service........................................................................... 11 7.0 Trip Generation/Distribution/Assignment............................................................................ 12 7.1 Trip Generation................................................................................................................. 12 7.1.1 Project Phase I Trip Generation............................................................................ 12 7.1.2 Project Phase II Trip Generation........................................................................... 12 7.1.3 Total Trip Generation ........................................................................................... 12 7.2 Trip Distribution/Assignment........................................................................................... 12 8.0 Cumulative Traffic Volumes................................................................................................... 14 8.1 Description of Projects...................................................................................................... 14 8.2 Summary of Cumulative Projects Trips............................................................................ 18 9.0 Analysis of Near-Term Scenarios........................................................................................... 21 9.1 Project Opening Day without Project............................................................................... 21 9.1.1 Intersection Analysis............................................................................................. 21 9.1.2 Segment Operations.............................................................................................. 21 LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc ii TABLE OF CONTENTS SECTION PAGE 9.2 Project Opening Day with Project Phase I........................................................................ 21 9.2.1 Intersection Analysis............................................................................................. 21 9.2.2 Segment Operations.............................................................................................. 25 9.3 Project Opening Day With Entire Project (Phases I & II)................................................ 25 9.3.1 Intersection Analysis............................................................................................. 25 9.3.2 Segment Operations.............................................................................................. 25 9.4 Project Opening Day With Entire Project & Cumulative Projects................................... 26 9.4.1 Intersection Analysis............................................................................................. 26 9.4.2 Segment Operations.............................................................................................. 26 10.0 Analysis of Long-Term Scenarios........................................................................................... 30 10.1 Build-out (Year 2025) Traffic Volumes........................................................................... 30 10.2 Build-out (Year 2025) Intersection Geometry.................................................................. 30 10.3 Build-out (Year 2025) Analysis........................................................................................ 31 10.3.1 Intersection Analysis............................................................................................. 31 10.3.2 Segment Operations.............................................................................................. 31 11.0 Site Access, On-Site Circulation and Roadway Segments ................................................... 35 11.1 Site Access........................................................................................................................ 35 11.1.1 Driveway #1 on Highway 79................................................................................ 35 11.1.2 Driveway #2 on Highway 79................................................................................ 35 11.1.3 Driveway #3 on De Portola Road......................................................................... 35 11.2 On-Site Circulation........................................................................................................... 35 11.3 Roadway Segments........................................................................................................... 35 11.3.1 Pio Pico Road........................................................................................................ 35 11.3.2 De Portola Road.................................................................................................... 36 12.0 Significance of Impacts and Mitigation Measures................................................................ 37 12.1 Significance of Impacts..................................................................................................... 37 12.1.1 Direct Impact (Phase II only)................................................................................ 37 12.1.2 Cumulative Impacts.............................................................................................. 37 12.2 City of Temecula – Regional Transportation Facility Mitigation Program...................... 38 12.2.1 City of Temecula Development Impact Fee (DIF)............................................... 38 12.2.2 Transportation Uniform Mitigation Fee (TUMF) Program.................................. 39 12.2.3 Assessment Districts / Community Facilities Districts......................................... 40 12.2.4 Federal, State and Special Legislative Funding Mechanisms............................... 41 12.3 Other Planned Network Improvements ............................................................................ 41 12.4 Mitigation Measures......................................................................................................... 42 12.4.1 Direct Impacts....................................................................................................... 46 12.4.2 Cumulative Impacts.............................................................................................. 47 LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc iii APPENDICES APPENDIX A. Intersection & Segment Manual Count Sheets and Historical Traffic Volumes on Highway 79 B. Riverside County Roadway Classification Table C. Peak Hour Intersection Analysis Worksheets - Existing D. Cumulative Projects Data E. Peak Hour Intersection Analysis Worksheets - Opening Day Without Project F. Peak Hour Intersection Analysis Worksheets - Opening Day With Project Phase I G. Peak Hour Intersection Analysis Worksheets - Opening Day With Entire Project (Phases I & II) H. Peak Hour Intersection Analysis Worksheets - Opening Day With Entire Project and Cumulative Projects I. City of Temecula Year 2025 Segment Volumes and Peak Hour Intersection Analysis Worksheets – Build-out (Year 2025 with Eastern By-Pass) J. DIF Information K. CIP Project Summary Sheets L. TUMF Information M. Assessment District Information N. Peak Hour Intersection Analysis Worksheets - Opening Day With Entire Project and Cumulative Projects (Mitigated – With Implementation of CIP projects & No Eastern By- Pass) LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc iv LIST OF FIGURES SECTION—FIGURE # FOLLOWING PAGE 1–1 Vicinity Map ............................................................................................................................... 1 1–2 Project Area Map.......................................................................................................................... 1 2–1 Site Plan......................................................................................................................................... 2 3–1 Existing Conditions Diagram................................................................................................. 5 3–2 Existing Traffic Volumes.............................................................................................................. 5 7–1 Opening Year Without Project Traffic Volumes......................................................................... 13 7–2 Project Traffic Distribution..................................................................................................... 13 7–3 Proposed Project Phase I Traffic Volumes................................................................................... 13 7-4 Opening Year With Project Phase I.............................................................................................. 13 7–5 Proposed Project Phase II Traffic Volumes................................................................................. 13 7–6 Proposed Entire Project (Phase I + Phase II) Traffic Volumes................................................... 13 7–7 Opening Year With Entire Project................................................................................................ 13 8–1 Cumulative Projects Location................................................................................................. 20 8–2 Cumulative Projects Traffic Volumes..................................................................................... 20 8–3 Opening Year With Entire Project & Cumulative Projects Traffic Volumes........................... 20 10–1 Year 2030 With Project Traffic Volumes.............................................................................. 34 12–1 Southwest TUMF Zone Transportation Improvement Program Projects.............................. 52 12–2 Riverside County Assessment Districts................................................................................. 52 LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc v LIST OF TABLES SECTION—TABLE # PAGE Table 3-1 Existing Segment Volumes .................................................................................................. 5 Table 4–1 Level of Service Thresholds For Signalized Intersections .................................................. 7 Table 6–1 Existing Intersection Operations........................................................................................ 10 Table 6–2 Existing Street Segment Operations.................................................................................. 11 Table 7-1 Project Trip Generation - Total Trips................................................................................. 13 Table 8-1 Cumulative Projects Trip Generation................................................................................. 19 Table 9–1 Project Opening Day Intersection Operations................................................................... 22 Table 9–2 Project Opening Day Segment Operations........................................................................ 24 Table 9–3 Entire Project and Cumulative Projects Intersection Operations....................................... 27 Table 9–4 Entire Project and Cumulative Projects Segment Operations ........................................... 29 Table 10–1 Build-out (Year 2025) Intersection Operations............................................................... 32 Table 10-2 Build-out (Year 2025) Segment Operations..................................................................... 34 Table 12-1 Cumulative Traffic Improvement Mitigation Measure Summary.................................... 44 Table 12–2 Existing + Project + Cumulative Intersection Operations With the Implementation of Mitigation Measures.................................................................................................................. 53 Table 12-3 Entire Project and Cumulative Projects Segment Operations - With Mitigation............. 54 LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 1 TRAFFIC IMPACT ANALYSIS TEMECULA HOSPITAL Temecula, California October 30, 2007 1.0 INTRODUCTION A hospital is proposed to be built on Highway 79 in the City of Temecula, Riverside District. The proposed project includes a 320-bed Hospital, a 140,000 SF medical office building, a 10,000 SF cancer rehabilitation center and an 8,000 SF rehabilitation and physical therapy center buildings, to be built in two phases. The following traffic study has been prepared to determine and evaluate the traffic impacts on the study area intersections and segments due to the development of the project. A description of each phase is detailed in Section 2.0, Project Description. The project site is located adjacent to Highway 79 on the north side, approximately 2 miles east of I- 15 in the City of Temecula. Figure 1-1 depicts the project vicinity while Figure 1-2 depicts the project area in detail. Included in this analysis are: ƒ Project Description ƒ Existing Conditions ƒ Analysis Approach and Methodology ƒ Significance Criteria ƒ Analysis of Existing Conditions ƒ Trip Generation/Distribution/Assignment ƒ Cumulative Traffic Volumes ƒ Analysis of Near-Term Scenarios ƒ Analysis of Long-Term Scenarios ƒ Site Access and On-Site Circulation ƒ Significance of Impacts and Mitigation Measures LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 2 2.0 PROJECT DESCRIPTION 2.1 Project Location The proposed project is located north of Highway 79, approximately 2 miles east of I-15 and west of Margarita Parkway, in the City of Temecula. 2.2 Project Description The Temecula Medical Center project proposes the construction of a 320-bed hospital with 140,000 SF of medical office space, a 10,000 SF cancer rehabilitation center and an 8,000 SF rehabilitation and physical therapy center. The existing site is currently undeveloped. The project proposes to be developed in two phases, as described below: Phase I: Phase I of the project would initially construct a 170-bed hospital with 80,000 SF of medical office space. Phase II: Phase II of the project would expand the hospital to its ultimate 320 bed configuration. In addition, the project would add 60,000 SF of medical office space, a 10,000 SF cancer rehabilitation center and an 8,000 SF rehabilitation and physical therapy center. 2.3 Project Access Site access for both phases is proposed via two driveways to Highway 79 and one driveway to De Portola Road. The western Highway 79 driveway is located directly opposite the Country Glen Way signalized intersection and the east driveway will function as a right turn in/right turn out driveway. The driveway to De Portola Road was assumed to be unsignalized with right-in/right-out and a left- in access. Figure 2-1 shows the site plan. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 3 3.0 EXISTING CONDITIONS The following is a brief description of the existing street system in the project area. Street classifications are based on the City of Temecula Circulation Plan. Figure 3-1 shows an existing conditions diagram. Appendix A includes brief descriptions of each roadway class in the City of Temecula Circulation Element. 3.1 Existing Street Network Highway 79 is classified as a Six-Lane Prime Arterial in the project area and is built as a six-lane roadway in the project vicinity. Curbside parking is generally prohibited along Highway 79, and the posted speed limit is 55 mph. La Paz Street is a two-lane undivided roadway in the project area. The posted speed limit is 35 mph, and curbside parking is generally permitted. La Paz Street is signalized at Highway 79. Pechanga Parkway is currently a four-lane undivided roadway in the project area. Curbside parking is prohibited at the approach to Highway 79, but is otherwise permitted. The posted speed limit on Pechanga Parkway is 50 mph. Pechanga Parkway is signalized at Highway 79. Avenida de Missiones is a four-lane undivided roadway in the project area. Curbside parking is generally permitted, and the posted speed limit is 35 mph. Margarita Road / Redhawk Parkway is classified as a four-lane Major roadway in the project area. Margarita Road is currently a four-lane divided roadway with curbside parking generally prohibited. Redhawk Parkway is also currently a four-lane divided roadway in the project area with curbside parking generally prohibited. The posted speed limit is 45 mph. Margarita Road / Redhawk Parkway is currently signalized at its intersection with Highway 79. Butterfield Stage Road is classified as a four-lane Major roadway in the project area. Butterfield Stage Road is currently a four-lane divided roadway in the project area with curbside parking generally prohibited. The posted speed limit is 50 mph. Butterfield Stage Road is signalized at Highway 79. De Portola Road is a four-lane road east of Margarita Road and a two-lane undivided roadway west of Margarita Road. Eastern By-Pass is a planned future facility between I-15, south of Highway 79 South and Borel Road in the northeastern section of the City. This facility will be called Deer Hollow Way, between I-15 and midway between Pechanga Parkway and Butterfield Stage Road. To the east of the previous section, this facility will be called Anza Road up to its terminus with Borel Road. This facility will include a new interchange at I-15, to be located south of Highway 79 South, which is approved by Riverside County Transportation Commission (RCTC) at a cost of $47,840,000. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 4 The Deer Hollow Way section of the Eastern By-Pass is planned to be a Six-Lane Divided Principal Arterial from I-15 to Rainbow Canyon Road and a Four-Lane Major Arterial from Rainbow Canyon Road to midway between Pechanga Parkway and Butterfield Stage Road. This roadway section is also approved by RCTC The Anza Road Section of the Eastern By-Pass is planned to be a Four-Lane Undivided Secondary Arterial from Midway between Pechanga Parkway and Butterfield Stage Road to Butterfield Stage Road and a Two-Lane Undivided Rural Highway between Butterfield Stage Road and Borel Road. With the completion of the Eastern By-Pass, the current traffic volumes on Highway 79 and at the I- 15 / Highway 79 South interchange are expected to reduce substantially. Currently, the implementation schedule for this improvement is not known and therefore, these improvements are not assumed in the near-term. However, the City of Temecula General Plan includes the Eastern Bypass in the Year 2025. Therefore, the Year 2025 analysis included in this report assumes the same. 3.2 Existing Traffic Volumes 3.2.1 Peak Hour Intersection Volume Counts Available AM and PM peak hour volumes were obtained from the City and new manual counts were conducted by LLG at the four locations listed below, in the second week of July, 2007. ƒ 1. Highway 79 / I-15 SB Ramps ƒ 2. Highway 79 / I-15 NB Ramps ƒ 3. Highway 79 / La Paz St ƒ 4. Highway 79 / Pechanga Pkwy Figure 3-2 depicts the existing peak hour intersection turning movement volumes. Appendix A contains the manual count sheets. 3.2.2 Segment Counts Available daily segment volumes were obtained from the City and new counts were conducted by LLG at the three locations listed below, in the second week of July, 2007. ƒ Highway 79 West of I-15 ƒ Butterfield Stage Road North of SR-79 ƒ Butterfield Stage Road South of SR-79 Table 3-1 summarizes the existing average daily traffic (ADT) volumes on the major area roadways. Figure 3-2 depicts the existing 24-hour segment volumes. Appendix A contains the segment count sheets. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 5 TABLE 3-1 EXISTING SEGMENT VOLUMES Street Segment Source ADT a Date Highway 79 West of I-15 LLG Engineers 19,700 07/11/07 I-15 to Pechanga Pkwy City of Temecula 77,600 2006 Pechanga Pkwy to Margarita Rd City of Temecula 39,000 2006 Margarita Rd to Butterfield Stage Rd City of Temecula 34,200 2006 Pechanga Parkway South of SR-79 City of Temecula 42,900 Feb-06 Butterfield Stage Road North of SR-79 LLG Engineers 12,800 07/11/07 South of SR-79 LLG Engineers 13,300 07/11/07 De Portola Road West of Margarita Rd City of Temecula 8,000 2006 Margarita Road / Redhawk Parkway Jedediah Smith Road to De Portola Road City of Temecula 17,700 2006 De Portola Road to Highway 79 City of Temecula 26,200 2006 South of Highway 79 City of Temecula 25,200 2006 Footnotes: a. Average Daily Traffic Volumes LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 6 4.0 ANALYSIS APPROACH AND METHODOLOGY This traffic analysis assesses the key intersections and street segments in the project area. All of these facilities are analyzed under existing and several future analysis timeframes to determine the project impacts on the street network during each timeframe. 4.1 Analysis Approach This report includes peak hour intersection and daily segment analysis of the following scenarios. Only segment analysis is conducted for the Build-out (Year 2025) scenario: ƒ Existing ƒ Opening Year Without Project (Existing + 3% growth in existing traffic for 3 years) ƒ Opening Year With Project Phase I ƒ Opening Year With Entire Project (Phases I & II) ƒ Opening Year With Entire Project (Phases I & II) and Cumulative Projects ƒ Build-out (Year 2025) Note: The growth in existing traffic volumes of three percent per year is based on the historical growth of traffic volumes on Highway 79, obtained from Caltrans (Appendix A). 4.2 Analysis Methodology There are different methodologies used to analyze signalized intersections, unsignalized intersections, street segments, freeways, and Congestion Management Program (CMP) arterials. The measure of effectiveness for intersection operations is Level of Service (LOS). In the 2000 Highway Capacity Manual (HCM), LOS for signalized intersections is defined in terms of delay. The level of service analysis results in seconds of delay expressed in terms of letters A through F. Delay is a measure of driver discomfort, frustration, fuel consumption, and lost travel time. 4.2.1 Signalized Intersections For signalized intersections, levels of service criteria are stated in terms of the average control delay per vehicle for a 15-minute analysis period. Control delay includes initial deceleration delay, queue move-up time, stopped delay, and final acceleration delay. Table 4–1 summarizes the delay thresholds for signalized intersections. Level of service A describes operations with very low delay, (i.e. less than 10.0 seconds per vehicle). This occurs when progression is extremely favorable, and most vehicles arrive during the green phase. Most vehicles do not stop at all. Short cycle lengths may also contribute to low delay. Level of service B describes operations with delay in the range 10.1 seconds and 20.0 seconds per vehicle. This generally occurs with good progression and/or short cycle lengths. More vehicles stop than for LOS A, causing higher levels of average delay. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 7 TABLE 4–1 LEVEL OF SERVICE THRESHOLDS FOR SIGNALIZED INTERSECTIONS Average Control Delay Per Vehicle (Seconds/Vehicle) Level of Service 0.0 < 10.0 A 10.1 to 20.0 B 21.1 to 35.0 C 35.1 to 55.0 D 55.1 to 80.0 E > 80.0 F Source: Highway Capacity Manual, 2000. Level of service C describes operations with delay in the range 20.1 seconds and 35.0 seconds per vehicle. These higher delays may result from fair progression and/or longer cycle lengths. Individual cycle failures may begin to appear. The number of vehicles stopping is significant at this level, although many still pass through the intersection without stopping. Level of service D describes operations with delay in the range 35.1 seconds and 55.0 seconds per vehicle. At level D, the influence of congestion becomes more noticeable. Longer delays may result from some combination of unfavorable progression, long cycle lengths, or higher v/c ratios. Many vehicles stop, and the proportion of vehicles not stopping declines. Individual cycle failures are more frequent. Level of service E describes operations with delay in the range of 55.1 seconds to 80.0 seconds per vehicle. This is considered to be the limit of acceptable delay. These high delay values generally indicate poor progression, long cycle lengths, and high v/c ratios. Individual cycle failures are frequent occurrences. Level of service F describes operations with delay in excess of over 80.0 seconds per vehicle. This is considered to be unacceptable to most drivers. This condition often occurs with over-saturation (i.e., when arrival flow rates exceed the capacity of the intersection). It may also occur at high v/c ratios below 1.00 with many individual cycle failures. Poor progression and long cycle lengths may also be major contributing causes to such delay levels. 4.2.2 Street Segments The street segments were analyzed on a daily basis without and with project conditions by comparing the Average Daily Traffic (ADT) volume to the Riverside County Capacity Standards. This table is included in Appendix B and provides Level of Service estimates based on traffic volumes and roadway characteristics. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 8 TABLE 4-2 VOLUME CAPACITY / LEVEL OF SERVICE FOR RIVERSIDE COUNTY ROADWAYS (1) Maximum Two-Way Traffic Volume (ADT)(2) Roadway Classification Number of Lanes Service Level A Service Level B Service Level C Service Level D Service Level E Collector 2 7,800 9,100 10,400 11,700 13,000 Major 4 20,460 23,870 27,300 30,700 34,100 Urban 4 21,540 25,130 28,700 32,300 35,900 Urban 6 32,340 37,730 43,100 48,500 53,900 Footnotes: 1. All capacity figures are based on optimum conditions and are intended as guidelines for planning purposes only. 2. Maximum two-way ADT values are based on the 1999 Modified Highway Capacity Manual Level of Service Tables as defined in the Riverside County Congestion Management Program. 3. Revised: March 2001 LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 9 5.0 SIGNIFICANCE CRITERIA Based on the City of Temecula General Plan, a significant impact is determined on a roadway segment or intersection with the addition of project traffic if: 1. The increase in the V/C (Volume / Capacity) ratio on roadway segments is greater than 2% 2. The increase in the delay at intersections is greater than 2 seconds The impact is direct if the project causes a reduction in the level of service (LOS) to below “D” and the impact is cumulative if the level of service is below LOS “D” prior to the addition of project. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 10 SIGNALIZED DELAY/LOS THRESHOLDS Delay LOS 0.0 < 10.0 A 10.1 to 20.0 B 20.1 to 35.0 C 35.1 to 55.0 D 55.1 to 80.0 E > 80.1 F 6.0 ANALYSIS OF EXISTING CONDITIONS 6.1 Peak Hour Intersection Levels of Service Table 6-1 summarizes the existing intersection operations. As seen in Table 6-1, all study area intersections are currently calculated to operate at LOS D or better except the Highway 79 / Pechanga Parkway intersection (LOS F during the PM peak hour). Appendix C contains the Existing peak hour intersection analysis worksheets. TABLE 6–1 EXISTING INTERSECTION OPERATIONS Existing Intersection Control Type Peak Hour Delaya LOSb AM 32.2 C 1. Highway 79 / I-15 SB Ramps Signal PM 37.5 D AM 12.0 B 2. Highway 79 / I-15 NB Ramps Signal PM 34.0 C AM 13.3 B 3. Highway 79 / La Paz St Signal PM 27.4 C AM 23.3 C 4. Highway 79 / Pechanga Pkwy Signal PM 73.9 E AM 10.5 B 5. Highway 79 / Jedediah Smith Rd Signal PM 15.6 B AM 6.4 A 6. Highway 79 / Avenida De Missiones Signal PM 7.6 A AM 5.0 A 7. Highway 79 / Country Glen Wy Signal PM 10.1 B AM 28.4 C 8. Highway 79 / Redhawk Pkwy / Margarita Rd Signal PM 32.1 C AM 18.8 B 9. Highway 79 / Butterfield Stage Rd Signal PM 20.2 C AM 13.9 B 10. De Portola Rd / Margarita Rd Signal PM 18.4 B Footnotes: a. Highway Capacity Manual average delay in seconds per vehicle b. Level of Service. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 11 6.2 Daily Street Segment Levels of Service Table 6-2 summarizes the existing street segment operations. As seen in Table 6-2, all study area street segments are currently calculated to operate at LOS D or better except the following: ƒ Highway 79 from I-15 to Pechanga Parkway (LOS F) ƒ Pechanga Parkway south of Highway 79 (LOS F) TABLE 6–2 EXISTING STREET SEGMENT OPERATIONS Street Segment Existing Roadway Class a Capacity (LOS E) b ADT c V/C d LOS e Highway 79 West of I-15 4-Ln Major Rd 34,100 19,700 0.578 A I-15 to Pechanga Pkwy 6-Ln Urban Rd 53,900 77,600 1.440 F Pechanga Pkwy to Margarita Rd 6-Ln Urban Rd 53,900 39,000 0.724 C Margarita Rd to Butterfield Stage Rd 6-Ln Urban Rd 53,900 34,200 0.635 B Pechanga Parkway South of Highway 79 4-Ln Major Rd 34,100 42,900 1.258 F Butterfield Stage Road North of Highway 79 4-Ln Major Rd 34,100 12,800 0.375 A South of Highway 79 4-Ln Major Rd 34,100 13,300 0.390 A De Portola Road West of Margarita Rd 2-Ln Collector 13,000 8,000 0.615 B Margarita Road / Redhawk Parkway Jedediah Smith Road to De Portola Road 4-Ln Major Rd 34,100 17,700 0.493 A De Portola Road to Highway 79 4-Ln Major Rd 34,100 26,200 0.730 C South of Highway 79 4-Ln Major Rd 34,100 25,200 0.702 C Footnotes: a. Roadway classification determined based on existing cross-sections. b. Roadway Capacities based on Riverside County Roadway Classification Table (see Appendix B). c. Average Daily Traffic Volumes. d. Volume / Capacity ratio e. Level of Service. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 12 7.0 TRIP GENERATION/DISTRIBUTION/ASSIGNMENT 7.1 Trip Generation Institute of Transportation Engineers (ITE) rate are generally used to determine trip generation in the City of Temecula. Hospital trip generation rates published by the San Diego Association of Governments (SANDAG) in the Brief Guide of Vehicular Traffic Generation Rates for the San Diego Region are higher than ITE rates and were therefore used to calculate the trip generation for the hospital. The trip generation rates in (ITE) Trip Generation were used for the Medical Office building. There are no standard trip generation rates available for the Cancer Rehabilitation Center and the Physical Rehabilitation Center. Hence, the rates for the Medical Office in ITE were used to estimate the trip generation. It is proposed to construct the project in two phases. Therefore, the project traffic generation was defined in two phases. Table 7–1 tabulates the Phase I and total project traffic generation. 7.1.1 Project Phase I Trip Generation The Project Phase I development is calculated to generate 6,290 ADT with 474 trips during the AM peak hour (350 inbound / 124 outbound) and 629 trips during the PM peak hour (214 inbound / 415 outbound trips). 7.1.2 Project Phase II Trip Generation The Project Phase II development is calculated to generate 5,820 ADT with 437 trips during the AM peak hour (324 inbound / 113 outbound) and 582 trips during the PM peak hour (197 inbound / 385 outbound trips). 7.1.3 Total Trip Generation The Entire Project (Phases I & II) is calculated to generate 12,110 ADT with 911 trips during the AM peak hour (674 inbound / 237 outbound) and 1,211 trips during the PM peak hour (411 inbound / 800 outbound trips). 7.2 Trip Distribution/Assignment The project trip distribution was estimated based on the location of residential neighborhoods, the location of other area hospitals, the site access and the roadway network. A growth rate of 3% per year for three years was applied to the existing traffic volumes to estimate Opening Year traffic conditions. This constitutes the baseline background traffic. The growth rate was utilized to account for area wide traffic growth. This growth rate of 3% per year is estimated, based on the average historical annual growth of traffic along Highway 79 (Appendix A). Figure 7-1 depicts the Opening Year without project traffic volumes. Figure 7-2 depicts the project trip distribution. Figure 7-3 depicts the Project Phase I traffic volumes, while Figure 7-4 depicts the Opening Year with Project Phase I traffic volumes. Figure 7-5 depicts the Project Phase II traffic volumes and Figure 7-6 depicts the Entire Project (Phases I & II) traffic volumes. Figure 7-7 depicts the Opening Year with Entire Project (Phases I & II) traffic volumes. L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 13 T AB L E 7- 1 P RO J E C T T RI P G EN E R A T I O N - T OT A L T RI P S AM P e a k H o u r P M P e a k H o u r Da i l y T r i p E n d s ( A D T ) a Vo l u m e V o l u m e La n d U s e Q u a n t i t y Ra t e V o l u m e % o f AD T In : O u t Sp l i t In O u t T o t a l % o f AD T In : Out Split In Out Total Ph a s e I Ho s p i t a l 1 7 0 B e d s 2 0 / B e d b 3 , 4 0 0 8 % 7 0 : 3 0 1 9 0 8 2 2 7 2 1 0 % 4 0 : 6 0 1 3 6 2 0 4 3 4 0 Me d i c a l O f f i c e 8 0 , 0 0 0 S F 3 6 . 1 3 / K S F c 2 , 8 9 0 7 % 7 9 : 2 1 1 6 0 4 2 2 0 2 1 0 % 2 7 : 7 3 7 8 2 1 1 2 8 9 Su b t o t a l P h a s e I 6, 2 9 0 35 0 1 2 4 4 7 4 214 415 629 Ph a s e I I Ho s p i t a l 1 5 0 B e d s 2 0 / B e d 3 , 0 0 0 8 % 7 0 : 3 0 1 6 8 7 2 2 4 0 1 0 % 4 0 : 6 0 1 2 0 1 8 0 3 0 0 Me d i c a l O f f i c e 6 0 , 0 0 0 S F 3 6 . 1 3 / K S F 2 , 1 7 0 7 % 7 9 : 2 1 1 2 0 3 2 1 5 2 1 0 % 2 7 : 7 3 5 9 1 5 8 2 1 7 Ca n c e r R e h a b C e n t e r d 10 , 0 0 0 S F 3 6 . 1 3 / K S F 3 6 0 7 % 7 9 : 2 1 2 0 5 2 5 1 0 % 2 7 : 7 3 1 0 2 6 3 6 Re h a b a n d P h y s T h e r a p y d 8, 0 0 0 S F 3 6 . 1 3 / K S F 2 9 0 7 % 7 9 : 2 1 1 6 4 2 0 1 0 % 2 7 : 7 3 8 2 1 2 9 Su b t o t a l P h a s e I I 5, 8 2 0 32 4 1 1 3 4 3 7 197 385 582 To t a l P r o j e c t 1 2 , 1 1 0 6 7 4 2 3 7 9 1 1 4 1 1 8 0 0 1 , 2 1 1 Fo o t n o t e s : a. Tr i p E n d s a r e o n e - w a y t r a f f i c m o v e m e n t , e i t h e r e n t e r i n g o r l e a v i n g . b. Br i e f G u i d e o f V e h i c u l a r T r a f f i c G e n e r a t i o n R a te s f o r t h e S a n D i e g o R e g i o n , A p r i l 2 0 0 2 , S A N D A G c. IT E Tr i p G e n e r a t i o n M a n u a l , 7 th E d i t i o n . d. Th e r a t e s f o r M e d i c a l O f f i c e i n t h e I T E T r i p G e n e r a t i o n M a n u a l , 7 th E d i t i o n w e r e u s e d s i n c e n o s e p a r a t e ra t e s a r e a v a i l a b l e f o r t h i s l a n d u s e . This rate is very conservative si n c e t h e s e u s e s a r e e x p e c t e d t o g e n e r a t e m u c h l o w e r t r a f f i c v o l u m e s . LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 14 8.0 CUMULATIVE TRAFFIC VOLUMES Based on discussions with City Staff, several area cumulative projects that have the potential to add traffic to the study area intersections and segments were identified. Brief descriptions of each cumulative project follow. Appendix D contains the Cumulative Projects Data. 8.1 Description of Projects 1. Summerhouse The Temecula Senior Care Facility includes a retirement community, congregate care and a medical office. The proposed project is estimated to generate 2,214 daily trips, with 128 trips in the AM peak hour (90 inbound and 38 outbound) and 205 trips in the PM peak hour (79 inbound and 126 outbound). 2. Temecula Creek Inn Temecula Creek Inn is a 500 single-family home Subdivision adjacent to the Temecula Creek golf course. The proposed project is estimated to generate 4,785 daily trips, with 375 trips in the AM peak hour (94 inbound and 281 outbound) and 505 trips in the PM peak hour (318 inbound and 187 outbound). 3. Tentative Map 30180 (Portion to be built) Tentative Tract Map 30180 includes commercial/retail uses located within the Creekside Plaza development, south of Highway 79 and east of Pechanga Parkway. The proposed project is estimated to generate 4,894 daily trips, with 114 trips in the AM peak hour (70 inbound and 44 outbound) and 450 trips in the PM peak hour (216 inbound and 234 outbound). 4. Temecula Creek Temecula Creek includes a hotel and convention center. The proposed project is estimated to generate 515 daily trips, with 29 trips in the AM peak hour (17 inbound and 12 outbound) and 46 trips in the PM peak hour (25 inbound and 21 outbound). 5. Vail Ranch Towne Center The Vail Ranch Towne Center includes office and retail uses. The proposed project is estimated to generate 6,036 daily trips, with 426 trips in the AM peak hour (266 inbound and 166 outbound) and 488 trips in the PM peak hour (193 inbound and 295 outbound). 6. Tentative Tract Map No. 29473 Tentative Tract Map No. 29473 includes single-family detached residential units. The proposed project is estimated to generate 2,326 daily trips, with 182 trips in the AM peak hour (46 inbound and 136 outbound) and 245 trips in the PM peak hour (158 inbound and 87 outbound). LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 15 7. Tentative Tract Map No. 29031 Tentative Tract Map No. 29031 – includes single-family detached residential units. The proposed project is estimated to generate 1,225 daily trips, with 96 trips in the AM peak hour (24 inbound and 72 outbound) and 129 trips in the PM peak hour (83 inbound and 46 outbound). 8. Tentative Tract Map No. 30052 Tentative Tract Map No. 30052 – includes single-family detached residential units. The proposed project is estimated to generate 1,168 daily trips, with 91 trips in the AM peak hour (23 inbound and 69 outbound) and 123 trips in the PM peak hour (79 inbound and 44 outbound). 9. Pechanga Casino Expansion Pechanga Casino Expansion – includes an expansion of the existing casino located southwest of the Highway 79/Pechanga Parkway intersection. The proposed project is estimated to generate 10,234 daily trips, with 452 trips in the AM peak hour (288 inbound and 164 outbound) and 477 trips in the PM peak hour (252 inbound and 225 outbound). 10. Margarita Canyon Margarita Canyon – includes commercial/retail land uses. The proposed project is estimated to generate 7,909 daily trips, with 184 trips in the AM peak hour (112 inbound and 72 outbound) and 733 trips in the PM peak hour (352 inbound and 381 outbound). 11. Rancho Community Church (Remaining) Rancho Community Church includes a variety of land uses other than the church including a private kindergarten – 8th grade school, a private high school, a preschool as well as 15 acres of general retail/office (retail) uses. The total project is estimated to generate 5,136 daily trips, with 706 trips in the AM peak hour (462 inbound and 244 outbound) and 410 trips in the PM peak hour (161 inbound and 249 outbound). 12. Wolf Creek Wolf Creek project originally proposed 1,000 single-family detached residential units. Now the project proposes 520 single family dwelling units, 12 acres of Community commercial and 8 acres of Neighborhood commercial development. These land uses are estimated to generate 22,739 daily trips, with 1,093 trips in the AM peak hour (525 inbound and 568 outbound) and 2,273 trips in the PM peak hour (1,198 inbound and 1,075 outbound). 13. Morgan Hill Morgan Hill– includes single-family detached residential units, an Elementary school, and a park. The proposed project is estimated to generate 5,430 daily trips, with 621 trips in the AM peak hour (253 inbound and 368 outbound) and 564 trips in the PM peak hour (338 inbound and 226 outbound). LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 16 14. Tentative Tract Map No. 24188 Tentative Tract Map 24188 - includes 291 apartments. The proposed project is estimated to generate 2,507 daily trips, with 2,507 trips in the 196 AM peak hour (49 inbound and 147 outbound) and 265 trips in the PM peak hour (170 inbound and 95 outbound). 15. Apis Plaza Apis Plaza includes commercial/retail, as well as a fast food restaurant, and a high turnover sit-down restaurant. The proposed project is estimated to generate 5,345 daily trips, with 230 trips in the AM peak hour (127 inbound and 103 outbound) and 462 trips in the PM peak hour (230 inbound and 232 outbound). 16. Paloma Del Sol Office Building Paloma Del Sol Office Building - includes 75,000 square feet of office space. The proposed project is estimated to generate 958 daily trips, with 134 trips in the AM peak hour (118 inbound and 16 outbound) and 147 trips in the PM peak hour (25 inbound and 122 outbound). 17. Park & Ride at Highway 79 / La Paz A 209 space Park & Ride facility is planned at the northeast corner of the Highway 79 / La Paz intersection. This facility is estimated to generate approximately 543 daily trips, with 272 trips in the AM peak hour (190 inbound and 82 outbound) and 272 trips in the PM peak hour (82 inbound and 190 outbound). 18. Temecula Lane I Temecula Lane I is a residential development with 96 single-family dwelling units and 332 multi- family dwelling units. This project is estimated to generate approximately 2,780 daily trips, with 212 trips in the AM peak hour (42 inbound and 170 outbound) and 263 trips in the PM peak hour (172 inbound and 91 outbound). 19. Roripaugh Ranch SPA The Roripaugh Ranch SPA is partly constructed. 1,800 single-family dwelling units remain to be constructed in this project. These remaining units are estimated to generate approximately 14,850 daily trips, with 1,269 trips in the AM peak hour (317 inbound and 952 outbound) and 1,445 trips in the PM peak hour (910 inbound and 535 outbound). 20. De Portola Meadows De Portola Meadows is a residential development with 147 single-family dwelling units and 156 multi-family dwelling units located west of Meadows Parkway and south of De Portola Road. This project is estimated to generate approximately 2,420 daily trips, with 186 trips in the AM peak hour (41 inbound and 145 outbound) and 236 trips in the PM peak hour (153 inbound and 83 outbound). LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 17 21. St Thomas of Canterbury St Thomas of Canterbury is a church / preschool project located south of Highway 79 and west of Avenida De Missiones. This project includes a 30,473 SF building. This project is estimated to generate approximately 682 daily trips, with 111 trips in the AM peak hour (59 inbound and 52 outbound) and 116 trips in the PM peak hour (55 inbound and 61 outbound). 22. Hemmingway at Redhawk Hemmingway at Redhawk is a residential development with 108 single-family dwelling units located north of Deer Hollow Way and East of Peppercorn Drive. This project is estimated to generate approximately 1,100 daily trips, with 85 trips in the AM peak hour (21 inbound and 64 outbound) and 115 trips in the PM peak hour (72 inbound and 43 outbound). 23. Temecula Professional Building II (PA06-0329) Temecula Professional Building II (PA06-0329) is an 11,595 SF office development located at the northeast corner of the Margarita Parkway / De Portola Road intersection. This project is estimated to generate approximately 254 daily trips, with 33 trips in the AM peak hour (29 inbound and 4 outbound) and 92 trips in the PM peak hour (16 inbound and 76 outbound). 24. Gateway Plaza Gateway Plaza is a two-storied, 30,573 SF office development located at the southwest corner of the Highway 79 / Avenida De Missiones intersection. This project is estimated to generate approximately 536 daily trips, with 24 trips in the AM peak hour (21 inbound and 3 outbound) and 113 trips in the PM peak hour (19 inbound and 94 outbound). 25. Redhawk Condos Redhawk Condos is a residential development with 97 multi-family dwelling units located at the Peach Tree Street / Deer Hollow Way intersection. This project is estimated to generate approximately 625 daily trips, with 50 trips in the AM peak hour (9 inbound and 41 outbound) and 59 trips in the PM peak hour (40 inbound and 19 outbound). 26. Stratford at Redhawk Stratford at Redhawk is a residential development with 106 single family dwelling units located at the southern limits of the City on Peachtree Street / Primrose Avenue. This project is estimated to generate approximately 1,120 daily trips, with 84 trips in the AM peak hour (21 inbound and 63 outbound) and 115 trips in the PM peak hour (72 inbound and 43 outbound). 27. Butterfield Station (Retail) Butterfield Station is a 7,300 SF retail development located off of Highway 79 between Mahlon Vail and Butterfield Stage Road. This project is estimated to generate approximately 5,535 daily trips, with 130 trips in the AM peak hour (79 inbound and 51 outbound) and 510 trips in the PM peak hour (291 inbound and 219 outbound). LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 18 28. De Portola Professional Offices De Portola Professional Offices is a 38,501 SF office development located at the southwest corner of the Margarita Parkway / De Portola Road intersection. This project is estimated to generate approximately 640 daily trips, with 87 trips in the AM peak hour (77 inbound and 10 outbound) and 120 trips in the PM peak hour (20 inbound and 100 outbound). 29. Heritage Hotel Heritage Hotel is a 142-room hotel development with a 5,500 SF restaurant located at the northeast corner of the Highway 79 / La Paz Street intersection. This project is estimated to generate approximately 1,760 daily trips, with 85 trips in the AM peak hour (51 inbound and 34 outbound) and 122 trips in the PM peak hour (68 inbound and 54 outbound). 30. Halcon de Rojo Halcon de Rojo is a 65,880 SF office development located at the northeast corner of the Highway 79 / Jedediah Smith Road intersection. This project is estimated to generate approximately 967 daily trips, with 134 trips in the AM peak hour (118 inbound and 16 outbound) and 153 trips in the PM peak hour (26 inbound and 127 outbound). 8.2 Summary of Cumulative Projects Trips Table 8-1 summarizes the individual cumulative project trip generation. As seen in Table 8-1, the cumulative projects are calculated to generate a total of 117,834 daily trips, with 7,576 trips in the AM peak hour (3,463 inbound and 4,113 outbound) and 11,452 trips in the PM peak hour (6,012 inbound and 5,441 outbound). Figure 8-1 depicts the location of each cumulative project, while Figure 8-2 depicts total Cumulative Projects traffic volumes. Figure 8-3 depicts the Opening Year with Entire Project and Cumulative Projects traffic volumes. L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 19 T AB L E 8- 1 C UM U L A T I V E P RO J E C T S T RI P G EN E R A T I O N AM P e a k H o u r P M P e a k H o u r Da i l y T r i p E n d s ( A D T ) a Vo l u m e V o l u m e La n d U s e Q u a n t i t y Ra t e V o l u m e % o f AD T In O u t T o t a l % o f AD T In Out Total 1. Su m m e r h o u s e 2 , 2 1 4 9 0 3 8 1 2 8 7 9 1 2 6 2 0 5 2. Te m e c u l a C r e e k I n n 4 , 7 8 5 9 4 2 8 1 3 7 5 3 1 8 1 8 7 5 0 5 3. Te n t a t i v e M a p 3 0 1 8 0 ( N o t B u i l t ) EZ L u b e 4 P o s i t i o n s 4 0 / P o s i t i o n 1 6 0 5 . 1 9 1 2 9 2 1 4 . 6 0 1 0 8 1 8 Ba n k 4 , 0 0 0 S F T = 1 8 2 . 3 4 X + 2 5 6 . 8 7 9 8 6 1 2 . 3 4 2 7 2 2 4 9 4 5 . 7 4 9 2 9 1 1 8 3 4. Te m e c u l a C r e e k 5 1 5 1 7 1 2 2 9 2 5 2 1 4 6 5. Va i l R a n c h T o w n e C e n t e r 6 , 0 3 6 2 6 6 1 6 6 4 3 2 1 9 3 2 9 5 4 8 8 6. Te n t a t i v e T r a c t M a p N o . 2 9 4 7 3 2 , 3 2 6 4 6 1 3 6 1 8 2 1 5 8 8 7 2 4 5 7. Te n t a t i v e T r a c t M a p N o . 2 9 0 3 1 1 , 2 2 5 2 4 7 2 9 6 8 3 4 6 1 2 9 8. Te n t a t i v e T r a c t M a p N o . 3 0 0 5 2 1 , 1 6 8 2 3 6 9 9 2 7 9 4 4 1 2 3 9. Pe c h a n g a C a s i n o E x p a n s i o n 1 0 , 2 3 4 2 8 8 1 6 4 4 5 2 2 5 2 2 2 5 4 7 7 10 . Ma r g a r i t a C a n y o n 7 , 9 0 9 1 1 2 7 2 1 8 4 3 5 2 3 8 1 7 3 3 11 . Ra n c h o C o m m u n i t y C h u r c h ( N o t B u i l t ) Mi d d l e S c h o o l 4 0 8 S t u d e n t s 1 . 6 2 / S tu d e n t 6 6 0 5 2 4 2 9 4 0 . 1 5 3 2 2 9 6 1 Hi g h S c h o o l 4 5 6 S t u d e n t s L n ( T ) = 0 . 8 1 L N ( X ) + 1 . 8 6 9 1 5 1 5 3 6 9 2 2 2 0 . 1 4 3 0 3 4 6 4 12 . Wo l f C r e e k Si n g l e F a m i l y R e s i d e n t i a l 5 2 0 U n i t s L n ( T ) = 0 . 9 2 L N ( X ) + 2 . 7 1 4 , 7 3 9 9 3 2 8 0 3 7 3 2 9 8 1 7 5 4 7 3 Co m m u n i t y C o m m e r c i a l 1 2 A c r e s 7 0 0 / A c r e 8 , 4 0 0 4 % 2 0 2 1 3 4 3 3 6 1 0 % 4 2 0 4 2 0 8 4 0 Ne i g h b o r h o o d C o m m e r c i a l 8 A c r e s 1 2 0 0 / A c r e 9 , 6 0 0 4 % 2 3 0 1 5 4 3 8 4 1 0 % 4 8 0 4 8 0 9 6 0 13 . Mo r g a n H i l l 5 , 4 3 0 2 5 3 3 6 8 6 2 1 3 3 8 2 2 6 5 6 4 14 . Te n t a t i v e T r a c t M a p N o . 2 4 1 8 8 2 , 5 0 7 4 9 1 4 7 1 9 6 1 7 0 9 5 2 6 5 15 . Ap i s P l a z a 5 , 3 4 5 1 2 7 1 0 3 2 3 0 2 3 0 2 3 2 4 6 2 16 . Pa l o m a D e l S o l O f f i c e B u i l d i n g 9 5 8 1 1 8 1 6 1 3 4 2 5 1 2 2 1 4 7 17 . Pa r k & R i d e a t H i g h w a y 7 9 / L a P a z 2 0 9 S p a c e s 2 . 6 / S p a c e 5 4 3 1 9 0 8 2 2 7 2 8 2 1 9 0 2 7 2 18 . Te m e c u l a L a n e I 7 , 9 0 9 1 1 2 7 2 1 8 4 3 5 2 3 8 1 7 3 3 Si n g l e F a m i l y R e s i d e n t i a l 9 6 U n i t s L n ( T ) = 0 . 9 2 L n ( X ) + 2 . 7 1 1 , 0 0 0 1 9 5 8 7 7 6 5 3 8 1 0 3 Mu l t i - F a m i l y R e s i d e n t i a l 3 3 2 U n i t s L n ( T ) = 0. 8 5 L n ( X ) + 2 . 5 5 1 , 7 8 0 2 3 1 1 2 1 3 5 1 0 7 5 3 1 6 0 L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 20 T AB L E 8- 1 (C ON T I N U E D ) C UM U L A T I V E P RO J E C T S T RI P G EN E R A T I O N AM P e a k H o u r P M P e a k H o u r Da i l y T r i p E n d s ( A D T ) a Vo l u m e V o l u m e La n d U s e Q u a n t i t y Ra t e V o l u m e % o f AD T In O u t T o t a l % o f AD T In Out Total 19 . Ro r i p a u g h R a n c h S P A 1 , 8 0 0 U n i t s L n ( T ) = 0 . 9 2 L N ( X ) + 2 . 7 1 1 4 , 8 5 0 3 1 7 9 5 2 1 2 6 9 9 1 0 5 3 5 1 , 4 4 5 20 . De P o r t o l a M e a d o w s Si n g l e F a m i l y R e s i d e n t i a l 1 4 7 U n i t s L n ( T ) = 0 . 9 2 L N ( X ) + 2 . 7 1 1 , 4 8 0 2 8 8 4 1 1 2 9 5 5 5 1 5 0 Mu l t i - F a m i l y R e s i d e n t i a l 1 5 6 U n i t s L n ( T )= 0 . 8 5 L n ( X ) + 2 . 5 5 9 4 0 1 3 6 1 7 4 5 8 2 8 8 6 21 . St T h o m a s o f C a n t e r b u r y 6 8 2 5 9 5 2 1 1 1 5 5 6 1 1 1 6 22 . He m m i n g w a y a t R e d h a w k 1 0 8 U n i t s L n ( T ) = 0 . 9 2 L N ( X ) + 2 . 7 1 1 , 1 0 0 2 1 6 4 8 5 7 2 4 3 1 1 5 23 . Te m e c u l a P r o f e s s i o n a l B u i l d i n g I I (P A 0 6 - 0 3 2 9 ) 11 , 5 9 5 S F L n ( T ) = 0 . 7 7 L n ( X ) + 3 . 6 5 2 5 4 2 9 4 3 3 1 6 7 6 9 2 24 . Ga t e w a y P l a z a 3 0 , 5 7 3 S F L n ( T ) = 0 . 7 7 L n ( X) + 3 . 6 5 5 3 6 2 1 3 2 4 1 9 9 4 1 1 3 25 . Re d h a w k C o n d o s 9 7 U n i t s L n ( T ) = 0 . 8 5 L n ( X ) + 2 . 5 5 6 2 5 9 4 1 5 0 4 0 1 9 5 9 26 . St r a t f o r d a t R e d h a w k 1 0 6 U n i t s L n ( T ) = 0 . 9 2 L N ( X ) + 2 . 7 1 1 , 1 2 0 2 1 6 3 8 4 7 2 4 3 1 1 5 27 . Bu t t e r f i e l d S t a t i o n ( R e t a i l ) 7 3 , 0 0 0 S F L n ( T ) = 0 . 6 5 L n ( X ) + 5 . 8 3 5 , 5 3 5 7 9 5 1 1 3 0 2 9 1 2 1 9 5 1 0 28 . De P o r t o l a P r o f e s s i o n a l O f f i c e s 3 8 , 5 0 1 S F L n ( T ) = 0 . 7 7 L n ( X ) + 3 . 6 5 6 4 0 7 7 1 0 8 7 2 0 1 0 0 1 2 0 29 . He r i t a g e H o t e l Ho t e l 1 4 2 R o o m s 8 . 9 2 / R o o m 1 , 2 7 0 4 7 3 4 8 1 7 . 4 9 4 0 4 1 8 1 Re s t a u r a n t 5 , 5 0 0 S F 8 9 . 9 5 / K S F c 4 9 0 0 . 8 1 4 0 4 7 . 4 9 2 8 1 3 4 1 30 . Ha l c o n d e R o j o 6 5 , 8 8 0 S F L n ( T ) = 0 . 7 7 L n ( X ) + 3 . 6 5 9 6 7 1 1 8 1 6 1 3 4 2 6 1 2 7 1 5 3 To t a l P r o j e c t 1 1 7 , 8 3 4 3 , 4 6 3 4 , 1 1 3 7 , 5 7 6 6 , 0 1 2 5 , 4 4 1 1 1 , 4 5 2 Fo o t n o t e : On l y t h e p o r t i o n s o f p r o j e c t s t h a t a r e y e t to b e b u i l t t h a t w e r e u n d e r c o n s t r u c t i o n a t t h e t i m e t h e t r a f f i c c o u n t s w e r e c o n d u c t ed a r e i n c l u d e d i n t h e a b o v e l i s t . LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 21 9.0 ANALYSIS OF NEAR-TERM SCENARIOS 9.1 Project Opening Day without Project As explained previously, Project Opening day without project represents existing traffic volumes with a growth of 3% per year for three years added. 9.1.1 Intersection Analysis Table 9-1 summarizes the intersection operations for the Opening Day without project. As seen in Table 9-1, all study area intersections are calculated to operate at LOS D or better except the following: • Highway 79 at I-15 SB Ramps • Highway 79 at I-15 NB Ramps • Highway 79 at Pechanga Parkway • Highway 79 at La Paz Street Appendix E contains the Opening Year Without Project peak hour intersection analysis worksheets. 9.1.2 Segment Operations Table 9-2 summarizes the street segment operations for the Opening Year Without Project. As seen in Table 9-2, all study area street segments are calculated to operate at LOS D or better except the following: ƒ Highway 79 from I-15 to Pechanga Parkway ƒ Pechanga Parkway south of Highway 79 9.2 Project Opening Day with Project Phase I Project Opening day with Project Phase I represents Project Opening Day traffic volumes with the addition of Project Phase I traffic volumes. 9.2.1 Intersection Analysis Table 9-1 summarizes the intersection operations for the Opening Day with Project Phase I. As seen in Table 9-1, all study area intersections are calculated to operate at LOS D or better with the addition of Project Phase I traffic except the following. • Highway 79 at I-15 SB Ramps • Highway 79 at I-15 NB Ramps • Highway 79 at Pechanga Parkway • Highway 79 at La Paz Street Appendix F contains the Opening Year With Project Phase I peak hour intersection analysis worksheets. L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 22 T AB L E 9– 1 P RO J E C T O PE N I N G D AY I NT E R S E C T I O N O PE R A T I O N S Ex i s t i n g Pr o j e c t O p e n i n g D a y Wi t h o u t P r o j e c t Pr o j e c t O p e n i n g D a y Wi t h P r o j e c t P h a s e I In t e r s e c t i o n Co n t r o l Ty p e Pe a k Ho u r De l a y a L O S b D e l a y a L O S b D e l a y a L O S b ∆ Delay c Impact Type AM 32 . 2 C 4 0 . 6 D 46 . 1 D 5.5 None 1. H i g h w a y 7 9 / I - 1 5 S B R a m p s Si g n a l PM 37 . 5 D 56 . 9 E 58 . 2 E 1.3 Cumulative AM 12 . 0 B 1 3 . 3 B 14 . 4 B 1.1 None 2. H i g h w a y 7 9 / I - 1 5 N B R a m p s Si g n a l PM 34 . 0 C 56 . 7 E 59 . 1 E 2.4 Cumulative AM 13 . 3 B 1 6 . 3 B 16 . 6 B 0.3 None 3. H i g h w a y 7 9 / L a P a z S t Si g n a l PM 27 . 4 C 58 . 5 E 61 . 2 D 2.7 Cumulative AM 23 . 3 C 2 6 . 6 C 27 . 8 C 1.2 None 4. H i g h w a y 7 9 / P e c h a n g a P k w y Si g n a l PM 73 . 9 E 10 9 . 7 F 11 4 . 3 F 4.6 Cumulative AM 10 . 5 B 1 1 . 0 B 11 . 2 B 0.2 None 5. H i g h w a y 7 9 / J e d e d i a h S m i t h R d Si g n a l PM 15 . 6 B 1 7 . 2 B 17 . 3 B 0.1 None AM 6. 4 A 6 . 7 A 8. 2 A 1.5 None 6. H i g h w a y 7 9 / A v e n i d a D e M i s s i o n e s Si g n a l PM 7. 6 A 8 . 7 A 9. 9 A 1.2 None AM 5. 0 A 5 . 2 A 26 . 6 C 21.4 None 7. H i g h w a y 7 9 / C o u n t r y G l e n W y Si g n a l PM 10 . 1 B 1 1 . 1 B 24 . 0 C 12.9 None AM 28 . 4 C 3 0 . 8 C 33 . 8 C 3.0 None 8. H i g h w a y 7 9 / R e d h a w k P k w y / Ma r g a r i t a R d Si g n a l PM 32 . 1 C 3 4 . 9 C 37 . 1 D 2.2 None L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 23 SIGNALIZED Delay LOS 0.0 < 10.0 A 10.1 to 20.0 B 20.1 to 35.0 C 35.1 to 55.0 D 55.1 to 80.0 E > 80.1 F T AB L E 9– 1 (C ON T I N U E D ) P RO J E C T O PE N I N G D AY I NT E R S E C T I O N O PE R A T I O N S Ex i s t i n g Pr o j e c t O p e n i n g D a y Wi t h o u t P r o j e c t Pr o j e c t O p e n i n g D a y Wi t h P r o j e c t P h a s e I In t e r s e c t i o n Co n t r o l Ty p e Pe a k Ho u r De l a y a L O S b D e l a y a L O S b D e l a y a L O S b ∆ Delay c Impact Type AM 18 . 8 B 2 0 . 0 B 20 . 4 C N o n e 9. H i g h w a y 7 9 / B u t t e r f i e l d S t a g e R d Si g n a l PM 20 . 2 C 2 2 . 8 C 24 . 1 C N o n e AM 13 . 9 B 1 4 . 0 B 14 . 3 B N o n e 10 . D e P o r t o l a R d / M a r g a r i t a R d Si g n a l PM 18 . 4 B 2 1 . 4 C 22 . 1 C N o n e Fo o t n o t e s : a. Hi g h w a y C a p a c i t y M a n u a l a v e r a g e de l a y i n s e c o n d s p e r v e h i c l e b. Le v e l o f S e r v i c e . c. ∆ d e n o t e s a n i n c r e a s e i n d e l a y d u e t o p r o j e c t . L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 24 T AB L E 9– 2 P RO J E C T O PE N I N G D AY S EG M E N T O PE R A T I O N S Ex i s t i n g Pr o j e c t O p e n i n g D a y Wi t h o u t P r o j e c t Pr o j e c t O p e n i n g D a y W i t h Pr o j e c t P h a s e I St r e e t S e g m e n t Ex i s t i n g Ro a d w a y Cl a s s a Ca p a c i t y (L O S E ) b AD T c V/ C d LO S e AD T c V/ C d LO S e AD T c V/ C d LOS e ∆ V/C f Impact Type Hi g h w a y 7 9 We s t o f I - 1 5 4 - L n M a j A r t 3 4 , 1 0 0 1 9 , 7 0 0 0 . 5 7 8 A 2 1 , 4 7 0 0 . 6 3 0 B 2 1 , 6 6 0 0 . 6 3 5 B 0 . 0 0 6 N o n e I- 1 5 t o P e c h a n g a P k w y 6 - L n P r i n A r t 5 3 , 9 0 0 77 , 6 0 0 1. 4 4 0 F 84 , 5 8 0 1. 5 6 9 F 86 , 4 7 0 1. 6 0 4 F 0.035 Cumulative Pe c h a n g a P k w y t o M a r g a r i t a R d 6 - L n P r i n A r t 5 3 , 9 0 0 3 9 , 0 0 0 0 . 7 2 4 C 4 2 , 5 1 0 0 . 7 8 9 C 4 5 , 7 8 0 0 . 8 4 9 D 0 . 0 6 1 N o n e Ma r g a r i t a R d t o B u t t e r f i e l d S t a g e R d 6 - L n P r i n A r t 5 3 , 9 0 0 3 4 , 2 0 0 0 . 6 3 5 B 3 7 , 2 8 0 0 . 6 9 2 B 3 8 , 4 8 0 0 . 7 1 4 C 0 . 0 2 2 N o n e Pe c h a n g a P a r k w a y So u t h o f H i g h w a y 7 9 4 - L n M a j A r t 3 4 , 1 0 0 42 , 9 0 0 1. 2 5 8 F 46 , 7 6 0 1. 3 7 1 F 47 , 0 7 0 1. 3 8 0 F 0.009 Cumulative Bu t t e r f i e l d S t a g e R o a d No r t h o f H i g h w a y 7 9 4 - L n M a j A r t 3 4 , 1 0 0 1 2 , 8 0 0 0 . 3 7 5 A 1 3 , 9 5 0 0 . 4 0 9 A 1 4 , 4 5 0 0 . 4 2 4 A 0 . 0 1 5 N o n e So u t h o f H i g h w a y 7 9 4 - L n M a j A r t 3 4 , 1 0 0 1 3 , 3 0 0 0 . 3 9 0 A 1 4 , 5 0 0 0 . 4 2 5 A 1 5 , 1 3 0 0 . 4 4 4 A 0 . 0 1 8 N o n e De P o r t o l a R o a d We s t o f M a r g a r i t a R d 2 - L n C o l 1 3 , 0 0 0 8 , 0 0 0 0 . 6 1 5 B 8 , 7 2 0 0 . 6 7 1 B 9 , 3 5 0 0 . 7 1 9 C 0 . 0 4 8 N o n e Ma r g a r i t a R o a d / R e d h a w k P a r k w a y Je d e d i a h S m i t h R d t o D e P o r t o l a R d 4 - L n M a j Ar t 3 4 , 1 0 0 1 7 , 7 0 0 0 . 4 9 3 A 1 9 , 2 9 0 0 . 5 3 7 A 2 0 , 2 3 0 0 . 5 6 4 A 0 . 0 2 6 N o n e De P o r t o l a R d t o H i g h w a y 7 9 4 - L n M a j A r t 3 4 , 1 0 0 2 6 , 2 0 0 0 . 7 3 0 C 2 8 , 5 6 0 0 . 7 9 6 C 2 9 , 5 0 0 0 . 8 2 2 D 0 . 0 2 6 N o n e So u t h o f H i g h w a y 7 9 4 - L n M a j A r t 3 4 , 1 0 0 2 5 , 2 0 0 0 . 7 0 2 C 2 7 , 4 7 0 0 . 7 6 5 C 2 8 , 1 0 0 0 . 7 8 3 C 0 . 0 1 8 N o n e Fo o t n o t e s : a. Ro a d w a y c l a s s i f i c a t i o n d e t e r m i n e d ba s e d o n e x i s t i n g c r o s s - s e c t i o n s . b. Ro a d w a y C a p a c i t i e s b a s e d o n R i v e r s i d e Co u n t y R o a d w a y C l a s s i f i c a t i o n T a b l e ( s e e Ap p e n d i x B ). c. Av e r a g e D a i l y T r a f f i c V o l u m e s . d. Vo l u m e / C a p a c i t y r a t i o e. Le v e l o f S e r v i c e . f. In c r e a s e i n V / C r a t i o LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 25 9.2.2 Segment Operations Table 9-2 summarizes the street segment operations for the Opening Day with Project Phase I. As seen in Table 9-2, all study area street segments are calculated to operate at LOS D or better except the following: ƒ Highway 79 from I-15 to Pechanga Parkway ƒ Pechanga Parkway south of Highway 79 9.3 Project Opening Day With Entire Project (Phases I & II) As explained previously, Project Opening day with entire project represents opening day with the addition of traffic volumes generated by the entire project. 9.3.1 Intersection Analysis Table 9-3 summarizes the intersection operations for the Opening Day with the Entire Project. As seen in Table 9-3, all study area intersections are calculated to operate at LOS D or better except the following: ƒ Highway 79 / I-15 SB Ramps (LOS E during the PM peak hour) ƒ Highway 79 / I-15 NB Ramps (LOS E during the PM peak hour) ƒ Highway 79 / La Paz Street (LOS E during the PM peak hour) ƒ Highway 79 / Pechanga Parkway (LOS F during the PM peak hour) Appendix G contains the Opening Year With the Entire Project peak hour intersection analysis worksheets. 9.3.2 Segment Operations Table 9-4 summarizes the street segment operations for the Opening Day with the Entire Project. As seen in Table 9-4, all study area street segments are calculated to operate at LOS D or better except the following: ƒ Highway 79 from I-15 to Pechanga Parkway ƒ Highway 79 from Pechanga Parkway to Margarita Road ƒ Pechanga Parkway south of Highway 79 LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 26 9.4 Project Opening Day With Entire Project & Cumulative Projects As explained previously, Project Opening day with entire project and cumulative projects represents opening day with entire project traffic volumes as well as cumulative project traffic volumes 9.4.1 Intersection Analysis Table 9-3 summarizes the peak hour intersection operations for the Project Opening day with Entire Project and Cumulative Projects. As seen in Table 9-3, all study area intersections continue to operate at poor LOS conditions except the following: ƒ Highway 79 / Butterfield Stage Rd ƒ De Portola Rd / Margarita Rd Appendix H contains the Opening Year With the Entire Project and Cumulative Projects peak hour intersection analysis worksheets. 9.4.2 Segment Operations Table 9-4 summarizes the street segment operations for the Project Opening day with Entire Project and Cumulative Projects. As seen in Table 9-4, all study area street segments are calculated to operate at a poor LOS except the following: ƒ Butterfield Stage north of Highway 79 ƒ Butterfield Stage south of Highway 79 ƒ De Portola Road west of Margarita Road ƒ Margarita Road from De Portola Road to Highway 79 ƒ Redhawk Parkway south of Highway 79 L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 27 T AB L E 9– 3 E NT I R E P RO J E C T A N D C UM U L A T I V E P RO J E C T S I NT E R S E C T I O N O PE R A T I O N S Pr o j e c t O p e n i n g Da y Wi t h P r o j e c t Ph a s e I Pr o j e c t O p e n i n g Da y Wi t h E n t i r e Pr o j e c t Project Opening Day With Entire Project & Cumulative Projects In t e r s e c t i o n Co n t r o l Ty p e Pe a k Ho u r De l a y a L O S b D e l a y a L O S b ∆ De l a y c Im p a c t Ty p e Delay a LOS b AM 4 6 . 1 D 4 9 . 1 D 3. 0 No n e 121.9 F 1. H i g h w a y 7 9 / I - 1 5 S B R a m p s Si g n a l PM 58 . 2 E 62 . 7 E 4. 5 Cu m u l a t i v e 2 2 4 . 3 F AM 1 4 . 4 B 1 4 . 6 B 0. 2 No n e 80.9 F 2. H i g h w a y 7 9 / I - 1 5 N B R a m p s Si g n a l PM 59 . 1 E 63 . 1 E 4. 0 Cu m u l a t i v e 2 9 8 . 2 F AM 1 6 . 6 B 1 6 . 9 B 0. 3 No n e 163.6 F 3. H i g h w a y 7 9 / L a P a z S t Si g n a l PM 61 . 2 D 65 . 0 E 3. 8 Cu m u l a t i v e 3 1 8 . 5 F AM 2 7 . 8 C 2 9 . 3 C 1. 5 No n e 125.0 F 4. H i g h w a y 7 9 / P e c h a n g a P k w y Si g n a l PM 11 4 . 3 F 11 5 . 2 F 0. 9 Cu m u l a t i v e 5 1 7 . 2 F AM 1 1 . 2 B 1 2 . 3 B 1. 1 No n e 3 0 . 7 C 5. H i g h w a y 7 9 / J e d e d i a h S m i t h R d Si g n a l PM 1 7 . 3 B 1 7 . 7 B 0. 4 No n e 123.5 F AM 8 . 2 A 8 . 3 A 0. 1 No n e 1 2 . 9 B 6. H i g h w a y 7 9 / A v e n i d a D e M i s s i o n e s Si g n a l PM 9 . 9 A 1 1 . 5 B 1. 6 No n e 95.3 F AM 2 1 . 5 C 2 2 . 9 C 1. 4 No n e 77.3 E 7. H i g h w a y 7 9 / C o u n t r y G l e n W y Si g n a l PM 2 4 . 0 C 3 4 . 1 C 10 . 1 No n e 244.6 F AM 3 3 . 8 C 3 6 . 6 D 2. 8 No n e 178.7 F 8. H i g h w a y 7 9 / R e d h a w k P k w y / M a r g a r i t a R d Si g n a l PM 37 . 1 D 39 . 6 D 2. 5 No n e 264.0 F L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 28 SIGNALIZED Delay LOS 0.0 < 10.0 A 10.1 to 20.0 B 20.1 to 35.0 C 35.1 to 55.0 D 55.1 to 80.0 E > 80.1 F T AB L E 9– 3 (C ON T I N U E D ) E NT I R E P RO J E C T A N D C UM U L A T I V E P RO J E C T S I NT E R S E C T I O N O PE R A T I O N S Pr o j e c t O p e n i n g Da y Wi t h P r o j e c t Ph a s e I Pr o j e c t O p e n i n g Da y Wi t h E n t i r e Pr o j e c t Project Opening Day With Entire Project & Cumulative Projects In t e r s e c t i o n Co n t r o l Ty p e Pe a k Ho u r De l a y a L O S b D e l a y a L O S b ∆ De l a y c Im p a c t Ty p e Delay a LOS b AM 2 0 . 4 C 2 0 . 9 C 0. 5 No n e 3 2 . 7 C 9. H i g h w a y 7 9 / B u t t e r f i e l d S t a g e R d Si g n a l PM 2 4 . 1 C 2 4 . 3 C 0. 2 No n e 3 7 . 9 D AM 1 4 . 3 B 1 4 . 9 B 0. 6 No n e 2 3 . 6 C 10 . D e P o r t o l a R d / M a r g a r i t a R d Si g n a l PM 2 2 . 1 C 2 3 . 3 C 1. 2 No n e 4 9 . 3 D Fo o t n o t e s : a. Hi g h w a y C a p a c i t y M a n u a l a v e r a g e de l a y i n s e c o n d s p e r v e h i c l e b. Le v e l o f S e r v i c e . c. ∆ d e n o t e s a n i n c r e a s e i n d e l a y d u e t o p r o j e c t . L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 29 T AB L E 9– 4 E NT I R E P RO J E C T A N D C UM U L A T I V E P RO J E C T S S EG M E N T O PE R A T I O N S Pr o j e c t O p e n i n g D a y W i t h Pr o j e c t P h a s e I Pr o j e c t O p e n i n g D a y W i t h En t i r e P r o j e c t Pr o j e c t O p e n i n g D a y W i t h Entire Project and Cumulative Projects St r e e t S e g m e n t Ex i s t i n g Ro a d w a y Cl a s s a Ca p a c i t y (L O S E ) b AD T c V/ C d LO S e AD T c V/ C d LO S e ∆ V/ C f Im p a c t Ty p e ADT c V/C d LOS e Impact Type Hi g h w a y 7 9 We s t o f I - 1 5 4 - L n M a j A r t 3 4 , 1 0 0 2 1 , 6 6 0 0 . 6 3 5 B 2 1 , 8 3 0 0 . 6 4 0 B 0 . 0 0 5 N o n e 32,490 0.953 E Cumulative I- 1 5 t o P e c h a n g a P k w y 6 - L n P r i n A r t 5 3 , 9 0 0 86 , 4 7 0 1. 6 0 4 F 88 , 2 2 0 1. 6 3 7 F 0.0 3 2 Cu m u l a t i v e 1 2 3 , 3 4 0 2 . 2 8 8 F C u m u l a t i v e Pe c h a n g a P k w y t o M a r g a r i t a R d 6 - L n P r i n A r t 5 3 , 9 0 0 4 5 , 7 8 0 0 . 8 4 9 D 48 , 8 1 0 0. 9 0 6 E 0.0 5 6 Di r e c t 8 2 , 4 8 0 1 . 5 3 0 F C u m u l a t i v e Ma r g a r i t a R d t o B u t t e r f i e l d S t a g e R d 6 - L n P r i n A r t 5 3 , 9 0 0 3 8 , 4 8 0 0 . 7 1 4 C 3 9 , 5 9 0 0 . 7 3 5 C 0 . 0 2 1 N o n e 59,880 1.111 F Cumulative Pe c h a n g a P a r k w a y So u t h o f H i g h w a y 7 9 4 - L n M a j A r t 3 4 , 1 0 0 47 , 0 7 0 1. 3 8 0 F 47 , 3 6 0 1. 3 8 9 F 0.0 0 9 No n e 7 0 , 0 1 0 2 . 0 5 3 F C u m u l a t i v e Bu t t e r f i e l d S t a g e R o a d No r t h o f H i g h w a y 7 9 4 - L n M a j A r t 3 4 , 1 0 0 1 4 , 4 5 0 0 . 4 2 4 A 1 4 , 9 2 0 0 . 4 3 8 A 0 . 0 1 4 N o n e 2 3 , 1 0 0 0 . 6 7 7 B N o n e So u t h o f H i g h w a y 7 9 4 - L n M a j A r t 3 4 , 1 0 0 1 5 , 1 3 0 0 . 44 4 A 1 5 , 7 1 0 0 . 4 6 1 A 0 . 0 1 7 N o n e 2 5 , 9 6 0 0 . 7 6 1 C N o n e De P o r t o l a R o a d We s t o f M a r g a r i t a R d 2 - L n C o l 1 3 , 0 0 0 9 , 3 5 0 0 . 7 1 9 C 9 , 9 3 0 0 . 7 6 4 C 0 . 0 4 5 N o n e 1 1 , 6 6 0 0 . 8 9 7 D N o n e Ma r g a r i t a R o a d / R e d h a w k P a r k w a y Je d e d i a h S m i t h R d t o D e P o r t o l a R d 4 - L n M a j A r t 35 , 9 0 0 2 0 , 2 3 0 0 . 5 6 4 A 2 1 , 1 0 0 0 . 5 8 8 A 0 . 0 2 4 N o n e 2 6 , 0 6 0 0 . 7 2 6 C N o n e De P o r t o l a R d t o H i g h w a y 7 9 4 - L n M a j A r t 3 5 , 9 0 0 2 9 , 5 0 0 0 . 8 2 2 D 3 0 , 3 7 0 0 . 8 4 6 D 0 . 0 2 4 N o n e 37,690 1.050 F Cumulative So u t h o f H i g h w a y 7 9 4 - L n M a j A r t 3 5 , 9 0 0 2 8 , 1 0 0 0 . 7 8 3 C 2 8 , 6 8 0 0 . 7 9 9 C 0 . 0 1 6 N o n e 38,540 1.074 F Cumulative Fo o t n o t e s : a. Ro a d w a y c l a s s i f i c a t i o n a s s u m e d b a se d o n e x i s t i n g c r o s s - s e c t i o n s . b. Ro a d w a y C a p a c i t i e s b a s e d o n R i v e r s i d e C o u n t y Ro a d w a y C l a s s i f i c a t i o n T a b l e ( s e e A p p e n d i x B ) . c. Av e r a g e D a i l y T r a f f i c V o l u m e s . d. Vo l u m e / C a p a c i t y r a t i o e. Le v e l o f S e r v i c e . f. In c r e a s e i n V / C r a t i o LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 30 10.0 ANALYSIS OF LONG-TERM SCENARIOS 10.1 Build-out (Year 2025) Traffic Volumes The City of Temecula Build-out volumes were obtained from the City of Temecula General Plan Update Circulation Element Traffic Study dated December 2004. It may be noted that the Build-out (Year 2025) network assumes a new traffic interchange at I-15, south of Highway 79 and a new road termed the Eastern By-Pass, which will extend from I-15 to Borel Road. This new circulation option will significantly reduce traffic volumes on the parallel portion of Highway 79. This facility was not included in the cumulative impact analysis because it will not be constructed for many years, and thus is not reasonably foreseeable within the horizon studied for cumulative impacts. A copy of the Build-out (Year 2025 volumes is included in Appendix I). The following methodology was utilized to estimate peak hour intersection volumes. Peak hour intersection turning movement volumes were estimated using a template in EXCEL developed by LLG. Future peak hour traffic volumes at an intersection are determined based on the relationship between existing peak hour turn movement and ADT volumes and the future ADT volumes. This same relationship can be assumed to generally continue in the future without the Eastern By-Pass. This relationship will likely change once the eastern By-Pass is built. This study includes analysis of Build-out peak hour intersection and segment volumes with the Eastern Bypass. Figure 10-1 depicts the forecasted Build-out peak hour and segment ADT volumes. 10.2 Build-out (Year 2025) Intersection Geometry All funded CIP improvements are assumed as the base geometry for the Year 2025 analysis as follows. The list of funded CIP projects that are relevant to the project study area is included in Table 12-1. ƒ I-15 / Highway 79 (South) interchange - Route 79 South at Interstate 15 Ultimate Interchange Improvements ƒ Route 79 South Re-striping from 6 to 8 lanes - Interstate 15 to Pechanga Parkway ƒ Route 79 South at Pechanga Parkway – Intersection Improvements – Dual Right Turn Lanes - Route 79 east to Pechanga Parkway south ƒ Route 79 South/Margarita Road Traffic Signal Coordination – Old Town Front Street to Butterfield Stage Road LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 31 10.3 Build-out (Year 2025) Analysis The intersection and segment operations at build-out (with the Eastern By-Pass) are compared to the existing + entire project + cumulative projects (with the existing network, and Eastern By-Pass), in order to determine the improvement in intersection and segment operations with the Eastern By- Pass. 10.3.1 Intersection Analysis Table 10-1 summarizes the Build-out (Year 2025 with Eastern By-Pass) peak hour intersection operations. As seen in Table 10-1, at Build-out , all Study Area intersections are calculated to operate at better levels of service and much lower delays than for the existing + project + cumulative projects (without the Eastern By-Pass). Appendix I contains the Build-out (Year 2025 with Eastern By-Pass) peak hour intersection analysis worksheets. 10.3.2 Segment Operations Table 10.2 summarizes the Build-out (Year 2025 with Eastern By-Pass) street segment operations. As seen in Table 10.2, all study area street segments are calculated to continue to operate at LOS D or better conditions except the following: ƒ Highway 79 from Pechanga Parkway to Margarita Road (LOS E) ƒ Highway 79 from Margarita Road to Butterfield Stage Road (LOS E) At Build-down (Year 2025 with Eastern By-Pass), all Study Area segments are calculated to operate at better levels of service than for the existing + project + cumulative projects Scenario (without the Eastern By-Pass). It may be noted that the City of Temecula General Plan Circulation Element assumes a two-lane facility (one lane in each direction) for the Eastern By-Pass. The volumes used in this analysis assume this two-lane cross-section. However, the Riverside County TUMF Program is planning to build the Eastern By-Pass as a four-lane facility (two lanes in each direction). Therefore, if the Eastern By-Pass were to be built as a four-lane facility, it would attract more traffic and the segment volumes and consequently, the intersection volumes along Highway 79 are expected to be lower than that used in this analysis. Thus, with a four-lane Eastern By-Pass facility, the intersections and segments are likely to operate better than with a two-lane Eastern By-Pass facility. L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 32 SIGNALIZED Delay LOS 0.0 < 10.0 A 10.1 to 20.0 B 20.1 to 35.0 C 35.1 to 55.0 D 55.1 to 80.0 E > 80.1 F T AB L E 10 – 1 B UI L D -OU T (Y EA R 20 2 5 ) I NT E R S E C T I O N O PE R A T I O N S Ex i s t i n g + E n t i r e P r o j e c t + Cu m u l a t i v e P r o j e c t s (N o E a s t e r n B y - P a s s ) Ye a r 2 0 2 5 (W i t h E a s t e r n B y - P a s s ) In t e r s e c t i o n Co n t r o l Ty p e Pe a k Ho u r De l a y a L O S b D e l a y a LOS b ∆ Delay In Seconds AM 12 1 . 9 F 19 . 7 B ( - ) 1 0 2 . 2 1. H i g h w a y 7 9 / I - 1 5 S B R a m p s S i g n a l PM 22 4 . 3 F 21 . 3 C ( - ) 2 0 3 . 0 AM 80 . 9 F 4. 5 A ( - ) 7 6 . 4 2. H i g h w a y 7 9 / I - 1 5 N B R a m p s S i g n a l PM 29 8 . 2 F 33 . 3 C ( - ) 2 6 4 . 9 AM 16 3 . 6 F 8. 7 A ( - ) 1 5 4 . 9 3. H i g h w a y 7 9 / L a P a z S t S i g n a l PM 31 8 . 5 F 22 . 7 C ( - ) 2 9 5 . 8 AM 12 5 . 0 F 20 . 0 B ( - ) 1 0 5 . 0 4. H i g h w a y 7 9 / P e c h a n g a P k w y S i g n a l PM 51 7 . 2 F 39 . 3 D ( - ) 4 7 7 . 9 AM 30 . 7 C 6. 5 A ( - ) 2 4 . 2 5. H i g h w a y 7 9 / J e d e d i a h S m i t h R d S i g n a l PM 12 3 . 5 F 15 . 4 B ( - ) 1 0 8 . 1 AM 12 . 9 B 3. 6 A ( - ) 9 . 3 6. H i g h w a y 7 9 / A v e n i d a D e M i s s i o n e s S i g n a l PM 95 . 3 F 6. 4 A ( - ) 8 8 . 9 AM 77 . 3 E 35 . 4 D ( - ) 4 1 . 9 7. H i g h w a y 7 9 / C o u n t r y G l e n W y S i g n a l PM 24 4 . 6 F 31 . 4 C ( - ) 2 1 3 . 2 Fo o t n o t e s : a. Hi g h w a y C a p a c i t y M a n u a l a v e r a g e de l a y i n s e c o n d s p e r v e h i c l e b. Le v e l o f S e r v i c e . c. ∆ d e n o t e s a n i n c r e a s e i n d e l a y d u e t o p r o j e c t . L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 33 Signalized Delay LOS 0.0 < 10.0 A 10.1 to 20.0 B 20.1 to 35.0 C 35.1 to 55.0 D 55.1 to 80.0 E > 80.1 F T AB L E 10 – 1 (C ON T I N U E D ) B UI L D -OU T (Y EA R 20 2 5 ) I NT E R S E C T I O N O PE R A T I O N S Ex i s t i n g + E n t i r e P r o j e c t + Cu m u l a t i v e P r o j e c t s (N o E a s t e r n B y - P a s s ) Ye a r 2 0 2 5 (W i t h E a s t e r n B y - P a s s ) In t e r s e c t i o n Co n t r o l Ty p e Pe a k Ho u r De l a y a L O S b D e l a y a L O S b ∆ Delay AM 17 8 . 7 F 22 . 4 C ( - ) 1 5 6 . 3 8. H i g h w a y 7 9 / R e d h a w k P k w y / M a r g a r i t a R d S i g n a l PM 26 4 . 0 F 79 . 5 E (-) 184.5 AM 32 . 7 C 25 . 4 C ( - ) 7 . 3 9. H i g h w a y 7 9 / B u t t e r f i e l d S t a g e R d S i g n a l PM 37 . 9 D 44 . 2 D 6 . 3 AM 23 . 6 C 14 . 4 B ( - ) 9 . 2 10 . D e P o r t o l a R d / M a r g a r i t a R d S i g n a l PM 49 . 3 D 21 . 5 C ( - ) 2 7 . 8 Fo o t n o t e s : a. Hi g h w a y C a p a c i t y M a n u a l a v e r a g e de l a y i n s e c o n d s p e r v e h i c l e b. Le v e l o f S e r v i c e . c. ∆ d e n o t e s a n i n c r e a s e i n d e l a y d u e t o p r o j e c t . L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 34 T AB L E 10 - 2 B UI L D -OU T (Y EA R 20 2 5 ) S EG M E N T O PE R A T I O N S Ex i s t i n g + E n t i r e P r o j e c t + C u m u l a t i v e P r o j e c t s (N o E a s t e r n B y - P a s s ) Ye a r 2 0 2 5 (W i t h E a s t e r n B y - P a s s ) Se g m e n t Ro a d w a y Cl a s s a LO S E Ca p a c i t y b Vo l u m e c V / C d L O S e Ro a d w a y C l a s s a LO S E Ca p a c i t y b Vo l u m e c V/C d LOS e SR - 7 9 We s t o f I - 1 5 4 - L n M a j A r t 3 4 , 1 0 0 32 , 4 9 0 0 . 9 5 3 E 4- L n M a j A r t 3 4 , 1 0 0 9 , 0 0 0 0 . 2 6 4 A I- 1 5 t o P e c h a n g a P k w y 6 - L n P r i n A r t 5 3 , 9 0 0 10 8 , 5 2 0 2 . 0 1 3 F 8- L n U r b a n A r t 7 1 , 8 0 0 5 9 , 0 0 0 0 . 8 2 2 D Pe c h a n g a P k w y t o M a r g a r i t a R d 6 - L n P r i n A r t 5 3 , 9 0 0 82 , 2 6 0 1 . 5 2 6 F 6- L n P r i n c i p a l A r t 5 3 , 9 0 0 51,000 0.946 E Ma r g a r i t a R d t o B u t t e r f i e l d S t a g e R d 6 - L n P r i n A r t 5 3 , 9 0 0 50 , 0 7 0 0 . 9 2 9 E 6- L n P r i n c i p a l A r t 5 3 , 9 0 0 50,000 0.928 E Pe c h a n g a P a r k w a y So u t h o f S R - 7 9 4 - L n M a j A r t 3 4 , 1 0 0 68 , 7 0 0 2 . 0 1 5 F 6- L n P r i n c i p a l A r t 5 3 , 9 0 0 2 9 , 0 0 0 0 . 5 3 8 A Bu t t e r f i e l d S t a g e R o a d No r t h o f S R - 7 9 4 - L n M a j A r t 3 4 , 1 0 0 2 3 , 1 0 0 0 . 6 7 7 B 4 - L n M a j A r t 3 4 , 1 0 0 1 9 , 0 0 0 0 . 5 5 7 A So u t h o f S R - 7 9 4 - L n M a j A r t 3 4 , 1 0 0 2 5 , 9 6 0 0 . 7 6 1 C 4 - L n M a j A r t 3 4 , 1 0 0 2 0 , 0 0 0 0 . 5 8 7 A De P o r t o l a R o a d We s t o f M a r g a r i t a R d 2 - L n C o l 1 3 , 0 0 0 1 0 , 8 9 0 0 . 8 3 8 D 4 - L n C o l 2 5 , 9 0 0 1 1 , 0 0 0 0 . 4 2 5 A Ma r g a r i t a R o a d / R e d h a w k P a r k w a y Je d e d i a h S m i t h R d t o D e P o r t o l a R d 4 - L n M a j A r t 3 5 , 9 0 0 2 6 , 0 6 0 0 . 7 2 6 C 4 - L n M a j A r t 3 4 , 1 0 0 1 1 , 0 0 0 0 . 3 0 6 A De P o r t o l a R d t o H i g h w a y 7 9 4 - L n M a j A r t 3 5 , 9 0 0 36 , 1 6 0 1 . 0 0 7 F 4- L n M a j A r t 3 4 , 1 0 0 2 3 , 0 0 0 0 . 6 4 1 B So u t h o f H i g h w a y 7 9 4 - L n M a j A r t 3 5 , 9 0 0 38 , 5 4 0 1 . 0 7 4 F 4- L n M a j A r t 3 4 , 1 0 0 2 7 , 0 0 0 0 . 7 5 2 C Fo o t n o t e s : a. Ci t y o f T e m e c u l a R o a d w a y C l a s s i f i c a t i o n b. Ri v e r s i d e C o u n t y R o a d w a y C a p a c i t y c. Vo l u m e C i t y o f T e m e c u l a G e n e r a l P l a n U p d a t e , C i r c u l a t i o n E l e m e n t T r a f f i c S t u d y . d. Vo l u m e / C a p a c i t y r a t i o e. Le v e l o f S e r v i c e LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 35 11.0 SITE ACCESS, ON-SITE CIRCULATION AND ROADWAY SEGMENTS 11.1 Site Access The project proposes three access driveways, two on Highway 79 and one on De Portola Road. The following are descriptions of each. 11.1.1 Driveway #1 on Highway 79 Driveway #1 on Highway 79 is the fourth (north) leg of the Highway 79 / Country Glen Way. This intersection is currently a signalized T-intersection. Modification of the current signal will be required to accommodate the fourth leg serving the project site and other related changes to geometry. The project should provide the following additional intersection geometry: ƒ A dedicated westbound right-turn lane, ƒ Dual eastbound left-turn lanes, and ƒ Dual left-turn lanes and a shared through/ right-turn lane in the southbound direction. 11.1.2 Driveway #2 on Highway 79 Driveway #2 on Highway 79 will be located at the west boundary of the property and will provide unsignalized right in/right-out only access. This 40-foot wide driveway should provide one inbound and one outbound lane. 11.1.3 Driveway #3 on De Portola Road Driveway #3 on De Portola Road will provide unsignalized right-in / right-out and left-in only access. Left-turns out of the hospital should be prohibited. This 40-foot wide driveway should provide one inbound and one outbound lane. 11.2 On-Site Circulation The hospital and other related buildings are located approximately in the center of the site, surrounded by parking. An adequate internal roadway system is provided to access each facility. Access to the surrounding street network is provided. 11.3 Roadway Segments 11.3.1 Pio Pico Road The proposed access point to De Portola Road is located a approximately 650 feet east of Pio Pico Road. Outbound project traffic would not utilize Pio Pico Road since outbound left-turns onto De Portola Road would be prohibited. While it would be possible for project inbound traffic on Margarita Road to utilize Pio Pico Road and De Portola Road, this is not expected to occur except on rare occasions. Southbound Margarita Road traffic would need to drive out of direction by turning right onto Pio Pico Road and then left (back eastbound) on De Portola Road to then access the site. This would require LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 36 more travel time than simply turning right onto De Portola Road from Margarita Road and then left into the site. In addition, the only drivers who would consider using Pio Pico Road are drivers who travel to the site every day. Therefore, no significant impacts to Pio Pico Road would occur. 11.3.2 De Portola Road Currently, De Portola Road is constructed as a two-lane roadway. Since there are no immediate plans to widen De Portola Road to four lanes and the first phase of the project will most likely be completed prior to any widening, a conservative approach assuming project traffic is added to a two lane De Portola Road was conducted. Tables 9-2, 9-4 and 10-2 summarize the segment operations for all the analysis scenarios. Based on existing roadway capacities for De Portola Road, LOS D or better (LOS D is the minimum LOS based on City standards) operations are calculated on the segment of De Portola Road for all analysis scenarios which shows that De Portola Road would be able to accommodate the additional traffic projected by the proposed project. The maximum ADT the project adds to De Portola Road is 1,210 trips. In addition, an analysis of the De Portola Road / Margarita Road intersection was conducted. The City’s goal for intersections and street segments is to operate at LOS D during the peak hours. As seen in Tables 9-1, 9-3 and 10-1, the De Portola Road / Margarita Road intersection is calculated to operate at LOS C or better for all the analysis scenarios during both the AM and PM peak hours, thereby also indicating that De Portola Road can accommodate the additional project related traffic. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 37 12.0 SIGNIFICANCE OF IMPACTS AND MITIGATION MEASURES 12.1 Significance of Impacts Based on the established significance criteria, the following significant impacts were calculated. Two direct impacts were calculated since project traffic caused the LOS to decrease from an acceptable LOS D to LOS E. Cumulative impacts were calculated at locations that already operate at LOS E or F without project traffic or locations where unacceptable levels of service occur only with the addition of cumulative projects traffic. 12.1.1 Direct Impact (Phase II only) a. Segment of Highway 79 between Pechanga Parkway and Margarita Road – This is a direct impact since with the addition of Project Phase II traffic this segment deteriorates from LOS D to LOS E. b. Highway 79 / Country Glen Way (Project Driveway) – This is a direct impact since this intersection is the main project driveway and the project is responsible for providing the north leg of this intersection which does not exist currently and will serve as the project access. 12.1.2 Cumulative Impacts Intersections c. Highway 79 / I-15 SB Ramps d. Highway 79 / I-15 NB Ramps e. Highway 79 / La Paz St f. Highway 79 / Pechanga Pkwy g. Highway 79 / Jedediah Smith Rd h. Highway 79 / Avenida De Missiones i. Highway 79 / Country Glen Way j. Highway 79 / Redhawk Pkwy / Margarita Rd Segments k. Highway 79 West of I-15 l. Highway 79 between I-15 and Pechanga Parkway m. Highway 79 between Pechanga Parkway and Margarita Road n. Highway 79 between Margarita Road and Butterfield Stage Road o. Pechanga Parkway south of Highway 79 p. Margarita Road from De Portola Road to Highway 79 q. Redhawk Parkway South of Highway 79 LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 38 12.2 City of Temecula – Regional Transportation Facility Mitigation Program The City of Temecula requires that identified direct project-related traffic impacts are mitigated and funded directly by the project applicant. Direct project-related mitigation measures required to mitigate project impacts will be implemented with construction of the Phase I improvements. In addition, the City of Temecula implements a comprehensive transportation system Capital Improvement Program (CIP) designed to address cumulative regional traffic impacts. The CIP has been designed to ensure that the regional circulation system as depicted in the Temecula General Plan Circulation Element is constructed to provide an acceptable level of service as development occurs. Funding for the regional circulation improvements identified in the CIP is derived from a variety of sources including City of Temecula Development Impact Fees (DIF), Assessment Districts (AD), the Transportation Uniform Mitigation Fee (TUMF), Community Facilities Districts (CFD), federal and state matching funds (SAFETEA-LU) and special legislative improvement districts (SB 621). The CIP prioritizes the funding, design and construction of individual transportation improvement projects to coincide with the commensurate level of service of roadway segments and intersections to adequately serve existing and future development. All of the CIP projects that provide for mitigation of regional cumulative traffic impacts have identified 100% of the funding required to construct the proposed improvement. Many of the CIP projects are currently 100% funded and the transportation portion of the DIF fee for this project has the effect of reimbursing the improvement fund for funds advanced for the impacted facilities, and thus will be applied to other regional CIP projects. All of the above referenced documents are available for review at the City of Temecula Planning Department. The following sections describe the transportation facility improvement funding programs. The CIP sheets are documented in Appendix J. 12.2.1 City of Temecula Development Impact Fee (DIF) Development Impact Fees (DIF) are collected to fund a portion of the new infrastructure that is needed to provide services to new development. Transportation improvements are the largest portion of the DIF fees. DIF fees are charged when: ƒ Construction permits are issued in a fee area or, in the case of water and wastewater, when the development ties into City services ƒ A new use, such as a new structure or expanded structure, is requested ƒ A change to a more intense use is requested ƒ A property adds new water or sewer service ƒ Additional Drainage Fixture Units are added to an existing structure LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 39 ƒ Impact fees are based on the type of land use being developed, the building area, gross site area, water meter sizes and the drainage fixture characteristics of the proposed development ƒ The amount charged for impact fees is based on the estimated demand the development will place on City services and the estimated taxes the new development will generate pay for new infrastructure. The current Development Impact Fee (DIF) for the proposed project is $4.75/SF for office land uses and $5.66/SF for service commercial land uses. The proposed project will pay $3,077,065 in current DIF fees. DIF fees are adjusted on a regular basis to keep pace with construction costs and inflation and are payable at building permit, so the amount actually paid could be more than under the current rates. Documentation regarding the adoption and implementation of the DIF program are included in Appendix K. 12.2.2 Transportation Uniform Mitigation Fee (TUMF) Program The County of Riverside and the Cities of Western Riverside County enacted the Transportation Uniform Mitigation Fee (TUMF). The purpose of the TUMF program is to provide a supplemental revenue stream to support the shortfall from traditional funding sources for regional transportation facilities. The TUMF program funds the mitigation of traffic impacts from new development on the regional system of Highways and arterials. The TUMF program also ensures that new developments pay their fair share towards providing the needed regional infrastructure improvements TUMF fees can only be used to mitigate the impacts of new development on the network of roads, bridges, interchanges and intersection that are identified under the TUMF program. The TUMF program involves development of policies, identification of transportation improvements, traffic modeling, cost estimates and fee scenarios. However, it should be noted that the mitigation fees collected through the TUMF program can be utilized only towards the capital costs of facilities and not for operation or maintenance costs. The fee calculations are based on the proportional allocation of the costs of proposed transportation improvements based on the cumulative transportation system impacts of different types of new developments. Fees are directly related to the forecast rate of growth and trip generation characteristics of different categories of new development. The TUMF program collects fees by the following land use categories ƒ Single family residential ƒ Multi-family residential ƒ Industrial LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 40 ƒ Retail ƒ Service commercial The current TUMF Fee for the proposed project is $5.71/SF for office land uses and $5.71/SF for service commercial land uses. Under the current TUMF fee structure, the proposed project would have to $3,232,774 in current TUMF fees. TUMF fees are adjusted on a semi-annual basis, and are payable at building permit, thus the amount actually paid could be more than the current fees. Figure 12-1 depicts the TUMF facilities in the County. Documentation regarding the TUMF program are attached as Appendix L. 12.2.3 Assessment Districts / Community Facilities Districts Assessment Districts (AD) and Community Facilities Districts (CFD) are special districts formed by a local government agency (County, City, Water District, etc.) that include property that would receive direct benefit from the construction of new public improvements or from the maintenance of existing public improvements. The proposed project is located with Assessment District 159 (AD 159), which encumbers a large area east of Interstate 15 and north and south of Route 79 south. The applicant has been paying assessment district fees for many years and will continue to do so until the assessment district is retired. The primary improvement funded by AD 159 is the widening of Route 79 south from 2 lanes to 6 lanes, between Interstate 15 and Butterfield Stage Road. This major regional circulation system improvement has been completed and provides for a significant increase in circulation system capacity in the vicinity of the proposed project. In addition, regional transportation improvements in the vicinity of the proposed project are included in Crown Hill CFD and the Morgan Hill CFD. The local agency that forms the assessment district sells bonds to raise the money to build or acquire the public improvement. The agency then levies a special assessment against each parcel of land within the district, in proportion to its share of benefit from the improvement. Factors that determine the amount of benefit received may include the size of the lot or the proximity to the improvement being financed. The special assessment is payable through annual installments over the life of the bond issue, which is typically 15 to 20 years, but may be as many as 40 years depending on the terms of the bond issue. The owners of the assessed land repay the bonds through annual assessments, which are included on the County's general property tax bill. Documentation regarding the Assessment Districts is included in Appendix M. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 41 12.2.4 Federal, State and Special Legislative Funding Mechanisms In addition to DIF fees, TUMF fees, CFD’s and Assessment Districts, Federal and State matching funds (SAFETEA-LU and SB 621 – Indian Gaming Special Distribution Fund) are available for use in funding regional circulation system improvements. 12.3 Other Planned Network Improvements In addition to the regional circulation facilities currently programmed into the City of Temecula CIP, TUMF, assessment districts and/or community facilities districts, there are several regional transportation facilities that are in the planning stages that have not yet been incorporated into any of the transportation planning/funding documents to date. The Eastern Bypass is a planned future regional transportation facility connecting I-15, south of Highway 79 South and Borel Road/Washington Street in the northeastern section of the City. This regional transportation facility will provide for significant traffic relief along Route 79, southern Pechanga Parkway and the entire circulation system within the vicinity of the project. This facility will be called Deer Hollow Way, between I-15 and midway between Pechanga Parkway and Butterfield Stage Road. To the east of the previous section, this facility will be called Anza Road up to its terminus with Borel Road. This facility will include a new interchange at I-15, to be located south of Highway 79 South, which is approved by Riverside County Transportation Commission (RCTC) at a preliminary cost of $47,840,000. The Deer Hollow Way section of the Eastern Bypass is planned to be a Six-Lane Divided Principal Arterial from I-15 to Rainbow Canyon Road and a Four-Lane Major Arterial from Rainbow Canyon Road to midway between Pechanga Parkway and Butterfield Stage Road. This roadway section is also approved by RCTC. The Anza Road Section of the Eastern Bypass is planned to be a four-lane Undivided Secondary Arterial from Midway between Pechanga Parkway and Butterfield Stage Road to Butterfield Stage Road and a Two-Lane Undivided Rural Highway between Butterfield Stage Road and Borel Road. Since the Eastern Bypass (a regional transportation facility) has not been funded or programmed into the City of Temecula CIP or the TUMF program, it has not been incorporated into the ultimate circulation system expected to be in place at build-out of the proposed project. Analysis of the year 2025 traffic conditions, including the Eastern Bypass, and discussed in Section 3.3.10, shows that all area intersections and segments will operate at acceptable levels of service in 2025, with the exception of the following: ƒ Highway 79 from Pechanga Parkway to Margarita Road (LOS E) ƒ Highway 79 from Margarita Road to Butterfield Stage Road (LOS E) Based upon this analysis, cumulative traffic impacts can be considered temporary until such time as the Eastern Bypass is built and operational. Once the Eastern Bypass project LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 42 is constructed, levels of service along all project impacted roadway segments and intersections are expected to operate at acceptable levels of service with the exception of the above outlines segments, which are slightly over the significance threshold. 12.4 Mitigation Measures The projects / improvements listed in Table 12-1 are planned already separately from the project, and if completed by others, the project’s payment of fees addresses its impacts. If, however, the improvements are not completed by others, the hospital must complete those improvements before obtaining the encroachment permit(s) from the City, and could get reimbursed for a portion of the costs, thus ensuring that the improvements will be in place prior to the hospital opening. To ensure the improvements are completed prior to occupancy of the hospital building, the project must be conditioned to prevent the occupancy of any building outside of Phase IA until after the City has issued a certificate of occupancy for any building in Phase IA. See mitigation measure 3.3-11 below. It may be noted that: ƒ As compared to the existing transportation system, the Project will have the impacts identified above. ƒ There are a series of planned improvements that will be completed by others in the next few years (Table 12-1). ƒ With completion of all of these improvements (and the project specific improvements as discussed for access points to the hospital site – i.e. the project specific impact mitigations), the project’s impacts will be less than significant, the project is still obligated to pay its DIF and TUMF fees in order to pay its fair share of the improvement costs (which are in effect being fronted by DIF and TUMF). ƒ In the event these improvements are not completed before the hospital opens (except for the interchange), there is a potentially significant impact. That residual impact is mitigated by requiring the hospital to complete the improvements before receiving any encroachment permit from the City. The projects / improvements listed in Table 12-1 are already planned separate from the proposed project. If these projects / improvements listed in Table 12-1 are completed by others, the project’s fee payments will addresses its own impacts. If, however, the improvements are not completed by others, the hospital must complete those improvements before the issuance of a certificate of occupancy for any building in Phase IA, and could get reimbursed for a portion of the costs, thus ensuring that the improvements will be in place prior to the hospital opening up. It may be noted that: ƒ As compared to the existing transportation system, the Project will have the impacts identified above. ƒ There are a series of planned improvements that will be completed by others in the next few years (Table 3.3-15). L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 43 T AB L E 12 - 1 C UM U L A T I V E T RA F F I C I MP R O V E M E N T M IT I G A T I O N M EA S U R E S UM M A R Y Tr a f f i c I m p r o v e m e n t C u r r e n t S t a t u s F u n d i n g So u r c e / S t a t u s C I P R e f e r e n c e P r i o r i t y 1. Ro u t e 7 9 S o u t h W i d e n i n g - I n t e r s t a t e 1 5 t o Bu t t e r f i e l d S t a g e R o a d a Co m p l e t e d A s s e s s m e n t D i s t r i c t 1 5 9 DI F No t a P a r t o f C I P C o m p l e t e d 2. Ro u t e 7 9 S o u t h R e - s t r i p i n g f r o m 6 t o 8 l a n e s - In t e r s t a t e 1 5 t o P e c h a n g a P a r k w a y De s i g n A p p r o v e d Co n s t r u c t 2 0 0 7 - 2 0 0 8 DI F - $ 1 6 1 , 2 5 0 2 1 0 - 1 6 5 - 6 7 6 C I P - I 3. Ro u t e 7 9 S o u t h M e d i a n C o n s t r u c t i o n – In t e r s t a t e 1 5 t o B u t t e r f i e l d S t a g e R o a d In D e s i g n Co n s t r u c t 2 0 0 7 - 2 0 0 8 DI F - $ 1 9 0 , 0 0 0 2 1 0 - 1 6 5 - 6 2 2 C I P - I I 4. Ro u t e 7 9 S o u t h a t B u t t e r f i e l d S t a g e R o a d – In t e r s e c t i o n M o d i f i c a t i o n a Co m p l e t e d b y P r i v a t e De v e l o p m e n t Pr i v a t e D e v e l o p e r N o t a P a r t o f C I P C o m p l e t e d 5. Ro u t e 7 9 S o u t h a t I n t e r s t a t e 1 5 U l t i m a t e In t e r c h a n g e I m p r o v e m e n t s In D e s i g n Co n s t r u c t i n 2 0 1 1 C D F ( C r o w n H i l l ) - $ 5 0 2 , 2 1 0 C F D ( M o r g a n H i l l ) - $ 1 , 1 9 0 , 5 8 2 S B 6 2 1 F u n d i n g - $ $ 1 4 , 9 6 0 . 9 2 5 S A F T E A - L U - $ 1 , 6 0 0 , 0 0 0 T U M F – 6 , 0 0 0 , 0 0 0 T o t a l C o s t - $ 2 2 , 5 6 0 , 9 2 5 21 0 - 1 6 5 - 6 6 2 C I P - I 6. Ro u t e 7 9 S o u t h a t P e c h a n g a P a r k w a y – In t e r s e c t i o n I m p r o v e m e n t s – D u a l R i g h t T u r n La n e s - R o u t e 7 9 e a s t t o P e c h a n g a P a r k w a y so u t h In D e s i g n Co n s t r u c t i n 2 0 0 7 - 20 0 8 S B 6 1 2 F u n d i n g - $ 4 2 5 , 0 0 0 2 1 0 - 1 6 5 - 6 3 7 C I P - I 7. Ro u t e 7 9 S o u t h / M a r g a r i t a R o a d T r a f f i c S i g n a l Co o r d i n a t i o n – O l d T o w n F r o n t S t r e e t t o Bu t t e r f i e l d S t a g e R o a d In D e s i g n Co n s t r u c t 2 0 0 7 - 2 0 0 8 D I F – T r a f f i c S i g n a l s P o r t i o n o f $ 2 , 5 7 5 , 0 0 0 21 0 - 1 6 5 - 7 1 2 C I P – I Fo o t n o t e s : a. Th e s e i m p r o v e m e n t s h a v e b e e n c o m p l e t e d a n d a r e a s s u m e d a s t h e e x i s t i n g c o n d i t i o n s a n d a r e no t p a r t o f t h e r e c o m m e n d e d m i t i g a t i o n m e a s u r e s . L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 44 T AB L E 12 - 1 (C ON T I N U E D ) C UM U L A T I V E T RA F F I C I MP R O V E M E N T M IT I G A T I O N M EA S U R E S UM M A R Y Tr a f f i c I m p r o v e m e n t C u r r e n t S t a t u s F u n d i n g So u r c e / S t a t u s C I P R e f e r e n c e P r i o r i t y 8. Ro u t e 7 9 S o u t h / M a r g a r i t a R o a d Tr a f f i c S i g n a l C o o r d i n a t i o n – O l d To w n F r o n t S t r e e t to B u t t e r f i e l d St a g e R o a d – F i b e r o p t i c s In D e s i g n Co n s t r u c t 2 0 0 7 - 2 0 0 8 D I F – T r a f f i c S i g n a l s - $ 3 4 5 , 0 0 0 2 1 0 - 1 6 5 - 7 1 2 C I P - I 9. Ro u t e 7 9 S o u t h C C T V T r a f f i c Mo n i t o r i n g S y s t e m I n D e s i g n , C o n s t r u c t i n 20 1 0 - 2 0 1 1 S B 6 2 1 - $ 3 9 5 , 0 0 0 2 1 0 - 1 6 5 - 6 3 5 C I P - I 10 . Pe c h a n g a P a r k w a y I m p r o v e m e n t s Be t w e e n P e c h a n g a P a r k w a y Br i d g e a n d V i a E d u a r d o In D e s i g n – C o n s t r u c t 20 0 7 - 2 0 0 1 DI F F e e s CF D – W o l f C r e e k Pu b l i c L a n d s a n d H i g h w a y s Pr o g r a m Pe c h a n g a T r i b e C o n t r i b u t i o n Ra n c h o C a l i f o r n i a W a t e r D i s t r i c t 21 0 - 1 6 5 0 6 6 8 C I P - I 11 . Ea s t e r n B y - P a s s (F u t u r e ) In P l a n n i n g $ 4 7 , 5 0 0 , 0 0 0 – P r e l i m i n a r y Es t i m a t e N / A Will substantially reduce cumulative traffic impacts when constructed LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 45 ƒ With completion of all of these improvements (and the project specific improvements as discussed for access points to the hospital site – i.e. the project specific impact mitigations), the project’s impacts will be less than significant, the project is still obligated to pay its DIF and TUMF fees in order to pay its fair share of the improvement costs (which are in effect being fronted by DIF and TUMF). In the event these improvements (except for the interchange) are not completed before the hospital opens, there is a potentially significant impact. That residual impact is mitigated by requiring the hospital to complete the improvements before receiving a certificate of occupancy for any building in Phase IA from the City. 12.4.1 Direct Impacts The following regional circulation system mitigation measures shall be completed prior to issuance of any encroachment permit for project access to Highway 79 South or De Portola Road. Encroachment permits shall not be issued until the improvements are completed or completed, as determined by the Director of Public Works. a. Highway 79 between Pechanga Parkway and Margarita Road City of Temecula CIP entitled “SR 79 South / Margarita Road Traffic Signal Coordination – Old Town Front Street to Butterfield Stage Road”. The applicant shall pay required City of Temecula DIF fees prior to issuance of any City of Temecula building permit. Should the entire CIP funding not be in place at the time of issuance of a certificate of occupancy for any building in Phase IA, the applicant shall fund and implement the traffic signal coordination and establish a reimbursement agreement with the City of Temecula to be reimbursed for expenditures made on behalf of the city. However, at this time, the CIP calls for completion of the improvement in the Year 2008. b. Site Access and On-Site Circulation In addition to Mitigation Measure 12.4.1-a, the project proposes three access driveways, two on SR 79 and one on De Portola Road. The following improvements shall be completed prior to issuance of a certificate of occupancy for any building in Phase IA from the City of Temecula in order to mitigate impacts of the new access driveways, to existing facilities: ƒ Driveway #1 on SR 79: Driveway #1 on SR 79 is the fourth (north) leg of the SR 79 / Country Glen Way. This intersection is currently a signalized T-intersection. Modification of the current signal has already been completed to accommodate the fourth leg serving the project site and other related changes to geometry. The project shall provide the following additional intersection geometry. ⎯ A dedicated westbound right-turn lane on Highway 79, ⎯ Dual eastbound left-turn lanes Highway 79, and dual left-turn lanes and a shared through/ right-turn lane in the southbound direction exiting the project site. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 46 ƒ Driveway #2 on SR 79: Driveway #2 on SR 79 shall be located at the west boundary of the property and will provide unsignalized right in/right-out only access. This 40- foot wide driveway shall provide one inbound and one outbound lane. ƒ Driveway #3 on De Portola Road: Driveway #3 on De Portola Road will provide unsignalized right-in / right-out and left-in only access. Left-turns out of the hospital shall be prohibited. This 40-foot wide driveway shall provide one inbound and one outbound lane. ƒ The hospital and other related buildings are located approximately in the center of the site, surrounded by parking. An adequate internal roadway system shall be provided to access each facility and to provide adequate parking. 12.4.2 Cumulative Impacts The project shall participate in the funding and implementation of regional circulation system improvements through payment of established City of Temecula DIF fees, participation in the Riverside County Transportation Uniform Mitigation Fees (TUMF) Program and continued participation in Assessment District (AD 159) financing. These fees are collected as part of funding mechanisms aimed at ensuring that regional highways and arterial expansions keep pace with the projected development and population increases. The regional circulation system mitigation measures shall be constructed prior to issuance of a certificate of occupancy for any building in Phase IA. Certificates of occupancy for buildings in Phase IA shall not be issued until the improvements are completed. Additional funding sources have been identified for several of the regional transportation facilities (see Table 3.3-15). All available mitigation measures required to mitigate cumulative traffic impacts are summarized in Table 3.3-15 and documented following the table. No additional mitigation measures, beyond those identified in this section, are feasible due to the fact that upon completion off all identified mitigation measures, no additional regional circulation improvements can be accommodated due to the fact that the area is built out and that the necessary right of way cannot feasibly be acquired. Existing land use and development conditions preclude the ability to acquire additional right of way for additional circulation system improvements. As discussed above, implementation of the Eastern Bypass will provide for significant cumulative traffic impact relief with all project affected segments and intersections expected to operate at acceptable levels of service, however the Eastern Bypass was not considered in the cumulative analysis at this time because completion is expected to be too far in the future. Intersections The following regional circulation system mitigation measures shall be constructed prior to issuance of a certificate of occupancy for any building in Phase IA. Certificates of occupancy for buildings in Phase IA shall not be issued until the improvements are completed. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 47 The following improvement has been completed since the traffic counts were assessed for this study and is not considered a measure to mitigate the impacts of this project: ƒ State Route 79 South Widening – Interstate 15 to Butterfield Stage Road: The primary improvement funded by AD 159 is the widening of Route 79 south from 2 lanes to 6 lanes, between Interstate 15 and Butterfield Stage Road. This major regional circulation system improvement has been completed and provides for a significant increase in circulation system capacity in the vicinity of the proposed project. Also, completion of the planned improvements through the federal, state and special legislative funding mechanisms as mitigation for the identified project impacts shall be concluded upon certification of occupancy for Phase IB, which consists of construction of the one-story main hospital structure comprising approximately 162,650 square feet and a 6-story bed tower of approximately 122,755 square feet, as well as parking associated with the structure and tower. However, with the exception of Mitigation Measures “c” and “d”, the obligation to complete these planned improvements will transfer from the previously stated funding mechanisms to the hospital if in fact the improvements are not completed by before an issuance of a certification of occupancy for Phase IA c. Highway 79 / I-15 Southbound Ramps Intersection City of Temecula CIP project entitled “Interstate 15 / State Route 79 South Interchange” (Public Works Account No. 210.165.662) which will add lanes to the ramps at the interchange shall be completed through the design review process prior to the City’s issuance of any encroachment permit for the project. Note: Funding is secured through DIF fees, TUMF fees, CFDs, State and Federal matching funds and SB 621 funds and construction is expected in 2011. d. Highway 79 / I-15 Northbound Ramps Intersection City of Temecula CIP project entitled “Interstate 15 / State Route 79 South Interchange” (Public Works Account No. 210.165.662) which will add lanes to the ramps at the interchange shall be completed through the design review process prior to the City’s issuance of any encroachment permit for the project. Note: Funding is secured through DIF fees, TUMF fees, CFDs, State and Federal matching funds and SB 621 funds, and construction is expected in 2011. Mitigation Measures “c” and “d” require coordination with Caltrans and therefore cannot be guaranteed to be in place prior to occupancy of the hospital project, even though the interchange improvements are fully funded and expected to be in construction in the year 2011. Therefore, the mitigation is deemed infeasible, because of the uncertainty associated with control of the project by an outside public agency (Caltrans) and not the City of Temecula. Because the impact at the interchange LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 48 cannot be mitigated with certainty, the interchange impacts are considered cumulatively significant and unmitigable for which a Statement of Overriding Considerations will be required. e. Highway 79 / La Paz Street Intersection City of Temecula CIP entitled “Route 79 South Widening - Interstate 15 to Pechanga Parkway”, which will add a fourth through lane in each direction on SR 79 through La Paz Street shall be constructed prior to the City’s issuance of a certificate of occupancy for any building in Phase IA of the project. If not completed by others, the Applicant shall complete the improvements prior to the issuance of a certificate of occupancy for any building in Phase IA, subject to potential reimbursement from the City or other projects. Note: Funding is secured through DIF fees and participation in the TUMF program and construction is expected to occur in 2008. f. Highway 79 / Pechanga Parkway Intersection City of Temecula CIP entitled “State Route 79 South to Pechanga Parkway – Dual Right-Turn Lanes”, which will add a second eastbound right-turn lane on SR 79 at Pechanga Parkway shall be constructed prior to the City’s issuance of a certificate of occupancy for any building in Phase IA of the project. If not completed by others, the Applicant shall complete the improvements prior to the issuance of a certificate of occupancy for any building in Phase IA, subject to potential reimbursement from the City or other projects. Note: Funding is secured through DIF fees and participation in the TUMF program and SB 621 Funds, and construction is scheduled for 2008. g. Highway 79 / Jedediah Smith Road Intersection; h. Highway 79 / Avenida De Missiones Intersection; i. Highway 79 / Country Glen Way Intersection; and j. Highway 79 / Redhawk Pkwy / Margarita Road Intersection City of Temecula CIP entitled “SR 79 South / Margarita Road Traffic Signal Coordination – Old Town Front Street to Butterfield Stage Road” shall be completed prior to the City’s issuance of a certificate of occupancy for any building in Phase IA of the project. If not completed by others, the Applicant shall complete the improvements prior to the issuance of a certificate of occupancy for any building in Phase IA, subject to potential reimbursement from the City or other projects. Note: Funding is secured through DIF fees and participation in the TUMF program and SB 621 Funds, and construction is scheduled for 2008. This project will improve the signal coordination along SR 79, including the SR 79 / Jedediah Smith Road, SR 79 / Avenida De Missiones and SR 79 / Redhawk Pkwy / Margarita Road intersections, which will improve traffic flow through these LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 49 intersections. In addition, the project shall construct lane geometry improvements and modify the existing traffic signal at the main project driveway, prior to project operation. Note: Funding is secured through DIF fees, and construction is scheduled for 2008. Segments k. Highway 79 West of I-15 The mitigation measures listed for impacts c and d will also mitigate this impact. The improvements to the interchange will greatly improve traffic flow on this segment of SR 79. However, mitigation measures “c” and “d” require coordination with Caltrans and therefore cannot be guaranteed to be in place prior to occupancy of the hospital project, even though the interchange improvements are fully funded and expected to be in construction in the year 2011. Therefore, the mitigation is deemed infeasible, because of the uncertainty associated with control of the project by an outside public agency (Caltrans) and not the City of Temecula. Because the impact at the interchange cannot be mitigated with certainty, the interchange impacts are considered cumulatively significant and unmitigable for which a Statement of Overriding Considerations will be required. l. Highway 79 between I-15 and Pechanga Parkway The mitigation measures listed for impacts “e” and “f” will also mitigate this impact. m. Highway 79 between Pechanga Parkway and Margarita Road; n. Highway 79 between Margarita Road and Butterfield Stage Road The mitigation measures listed for impacts “g” will also mitigate this impact. o. Pechanga Parkway South of Highway 79 City of Temecula CIP for fiscal Years 2007-2011 entitled “Pechanga Parkway Improvements – Phase II” – Public Works Account No. 210.165.668, shall be completed prior to the City’s issuance of a certificate of occupancy for any building in Phase IA of the project. If not completed by others, the Applicant shall complete the improvements prior to the issuance of a certificate of occupancy for any building in Phase IA, subject to potential reimbursement from the City or other projects. Note: This project will add the third through lane on Pechanga Parkway in both directions. Funding is secured through DIF fees, CFD (Wolf Creek), Public Lands and Highway Program, Pechanga Tribe contributions and Rancho California Water District funding, and construction is scheduled between 2007 and 2011. p. Margarita Road from De Portola Road to Highway 79 The applicant shall pay required City of Temecula DIF fees prior to issuance of any City of Temecula encroachment permit. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 50 Note: No additional mitigation measures are feasible due to the fact that upon completion off all identified mitigation measures, no additional regional circulation improvements can be accommodated within the existing right of way. Existing land use and development conditions preclude the ability to acquire additional right of way for additional circulation system improvements along this segment. Implementation of the Eastern Bypass will provide for significant cumulative traffic impact relief with all project affected segments and intersections expected to operate at acceptable levels of service, however the Eastern Bypass was not considered in the cumulative analysis at this time because completion is expected to be too far in the future. q. Redhawk Parkway South of Highway 79 The applicant shall pay required City of Temecula DIF fees prior to issuance of any City of Temecula encroachment permit. Note: No additional mitigation measures are feasible due to the fact that upon completion off all identified mitigation measures, no additional regional circulation improvements can be accommodated within the right of way along this segment. Existing land use and development conditions preclude the ability to acquire additional right of way for additional circulation system improvements. Implementation of the Eastern Bypass will provide for significant cumulative traffic impact relief with all project affected segments and intersections expected to operate at acceptable levels of service, however the Eastern Bypass was not considered in the cumulative analysis at this time because completion is expected to be too far in the future. To ensure the improvements are completed prior to occupancy of the hospital building, occupancy of any building outside of Phase IA shall not be permitted until after the City has issued a certificate of occupancy for any building in Phase IA. No additional mitigation measures, beyond those identified in this section, are feasible due to the fact that upon completion off all identified mitigation measures, no additional regional circulation improvements can be accommodated within the existing right of way. Existing land use and development conditions preclude the ability to acquire additional right of way for additional circulation system improvements. CEQA requires that a lead agency shall neither approve nor implement a project as proposed unless the significant environmental effects of that project have been reduced to a less-than-significant level, essentially “eliminating, avoiding, or substantially lessening” the expected impact. As with the underlying environmental documents, if the lead agency approves the project despite residual significant adverse impacts that cannot be mitigated to a less-than-significant level, the agency must state the reasons for its action in writing. This “Statement of Overriding Considerations” must be included in the record of project approval. LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 51 Resulting Levels of Service following implementation of all available mitigation measures for all project area intersection and roadway segments are shown in Tables 3.3-16 and 3.3-17 respectively. As seen in Tables 3.3-16 and 3.3-17, all of the identified segments and intersections, with the exception of Route 79 South /I-15 Northbound ramps (AM) and the Route 79 South /Country Glenn Way (AM) intersection will continue to operate at unacceptable levels of service, following completion of all feasible mitigation measures, although the mitigation will in most cases substantially decrease the amount of delay that would otherwise be experienced. These cumulative traffic impacts are considered significant unavoidable adverse impacts, until such time as the Eastern Bypass is constructed, which would provide substantial relief to the regional circulation system. Appendix N contains the Existing + Project + Cumulative Projects analysis with the implementation of all mitigation measures. TABLE 12–2 EXISTING + PROJECT + CUMULATIVE INTERSECTION OPERATIONS WITH THE IMPLEMENTATION OF MITIGATION MEASURES Without Mitigation With Mitigation a Intersection Control Type Peak Hour Delayb LOSc Delayb LOSc AM 121.9 F 84.5 F 1. Highway 79 / I-15 SB Ramps Signal PM 224.3 F 160.9 F AM 80.9 F 19.0 B 2. Highway 79 / I-15 NB Ramps Signal PM 298.2 F 70.4 E AM 163.6 F 40.7 D 3. Highway 79 / La Paz St Signal PM 318.5 F 86.9 F AM 125.0 F 112.5 F 4. Highway 79 / Pechanga Pkwy Signal PM 517.2 F 365.6 F 5. Highway 79 / Jedediah Smith Rd Signal PM 123.5 F 75.3 E 6. Highway 79 / Avenida De Missiones Signal PM 95.0 F 60.6 E AM 77.3 E 15.7 B 7. Highway 79 / Country Glen Wy Signal PM 244.6 F 131.5 F AM 178.7 F 142.5 F 8. Highway 79 / Redhawk Pkwy / Margarita Rd Signal PM 264.0 F 212.5 F Footnotes: a. Mitigation does not include the planned Eastern By-Pass. b. Highway Capacity Manual average delay in seconds per vehicle c. Level of service L IN S C O T T , L AW & G RE E N S P A N , en g i n e e r s LLG Ref. 3-07-1752 Temecula Hospital N:\1752\Report\1752 Report.doc 52 T AB L E 12 - 3 E NT I R E P RO J E C T A N D C UM U L A T I V E P RO J E C T S S EG M E N T O PE R A T I O N S - W IT H M IT I G A T I O N Wi t h o u t M i t i g a t i o n W i t h M i t i g a t i o n Se g m e n t Ex i s t i n g Ro a d w a y C l a s s a LO S E Ca p a c i t y b Vo l c V / C d L O S e Mi t i g a t e d Ro a d w a y C l a s s a LO S E Ca p a c i t y b Vol c V/C d LOS e Hi g h w a y 7 9 f We s t o f I - 1 5 4 - L n M a j o r A r t 3 4 , 1 0 0 3 2 , 4 9 0 0 . 9 5 3 E 4 - L n M a j o r A r t 3 4 , 1 0 0 3 2 , 4 9 0 0 . 9 5 3 E I- 1 5 t o P e c h a n g a P k w y 6 - L n U r b a n A r t 5 3 , 9 0 0 1 2 3 , 3 4 0 2 . 2 8 8 F 8 - L n U r b a n A r t 7 1 , 8 0 0 1 2 3 , 3 4 0 1 . 7 1 8 F Pe c h a n g a P k w y t o M a r g a r i t a R d 6 - L n U r b a n A r t 5 3 , 9 0 0 8 2 , 4 8 0 1 . 5 3 0 F 6 - L n U r b a n A r t 5 3 , 9 0 0 8 2 , 4 8 0 1 . 5 3 0 F Ma r g a r i t a R d t o B u t t e r f i e l d S t a g e R d 6 - L n U r b a n A r t 5 3 , 9 0 0 5 9 , 8 8 0 1 . 1 1 1 F 6 - L n U r b a n A r t 5 3 , 9 0 0 5 9 , 8 8 0 1 . 1 1 1 F Pe c h a n g a P a r k w a y So u t h o f H w y 7 9 4 - L n M a j o r A r t 3 4 , 1 0 0 7 0 , 0 1 0 2 . 0 5 3 F 6 - L n U r b a n A r t 5 3 , 9 0 0 7 0 , 0 1 0 1 . 2 9 9 F Ma r g a r i t a R o a d / R e d h a w k P a r k w a y De P o r t o l a R d t o H w y 7 9 4 - L n M a j o r A r t 3 5 , 9 0 0 3 7 , 6 9 0 1 . 0 5 0 F 4 - L n M a j o r A r t 3 5 , 9 0 0 3 7 , 6 9 0 1 . 0 5 0 F So u t h o f H w y 7 9 4 - L n M a j o r A r t 3 5 , 9 0 0 3 8 , 5 4 0 1 . 0 7 4 F 4 - L n M a j o r A r t 3 5 , 9 0 0 3 8 , 5 4 0 1 . 0 7 4 F Fo o t n o t e s : a. Ro a d w a y c l a s s i f i c a t i o n a s s u m e d b a se d o n e x i s t i n g c r o s s - s e c t i o n s . b. Ro a d w a y C a p a c i t i e s b a s e d o n R i v e r s i d e C ou n t y R o a d w a y C l a s s i f i c a t i o n T a b l e ( s e e Ap p e n d i x B ). c. Av e r a g e D a i l y T r a f f i c V o l u m e s . d. Vo l u m e / C a p a c i t y r a t i o e. Le v e l ; o f S e r v i c e . f. On e C I P p r o j e c t p l a n s t o r e - s t r i p e t h e s e g m e n t f r o m I - 1 5 t o P e c h a ng a P a r k w a y f r o m t h e c u r r e n t S i x - L a n e P r i n c i p a l A r t e r i a l t o a n E i g h t - L a n e U r b a n A r t e rial. However, a se c o n d C I P p r o j e c t i n c l u d e s t h e i n s t a l l a t i o n of e q u i p m e n t t o p r o v i d e s i g n a l c o o r d i n a t i o n f r o m W e s t o f I - 1 5 t o M a r g a r i t a R o a d . Wh i l e i t i s n o t p o s s i b l e t o q u a n t i f y t h e be n e f i t t o t h e s e g m e n t o p e r a t i o n s , a l l i n t e r s e c t i o n s i n t h i s c o rr i d o r a r e c a l c u l a t e d t o o p e r a t e a l o w e r d e l a y s t h a n p r i o r t o c o or d i n a t i o n . T h e r o a d w a y c a p a c i t y i s a C i t y st a n d a r d . MEMORANDUM To: Mr. Eric Ruby & Mr. Chris Knopp ESA Community Development Date: September 25, 2007 From: Narasimha Prasad, Senior Transportation Engineer LLG, Engineers LLG Ref: 3-07-1752 Subject: Temecula Hospital – Alternative 7 LLG Engineers conducted a Build-out (Year 2025) segment analysis of roadways potentially impacted by Alternative 7 of the Temecula Hospital Project. In Alternative 7, the proposed project would be located at the southwest corner of Cherry Street and Diaz Road in the northwestern portion of the City of Temecula. The Build-out segment volumes were obtained from the City of Temecula General Plan Update Circulation Element Traffic Study dated December 2004. All planned network (CIP) improvements are assumed to be implemented and the City street network is assumed to be built to the planned Circulation Element Classification. The project traffic was added to these segments and the Build-out + Project traffic volumes were determined. Table A summarizes the without and with project Build-out segment volumes. As seen in Table A, the segment of Winchester Road from Diaz Road to Jefferson Avenue is calculated to operate at LOS F with the project traffic. The segment of Jefferson Avenue between Winchester Avenue and Overland Drive is calculated to operate at LOS F, both without and with the project traffic. These would represent significant impacts requiring mitigation. Please call if you have any questions or need additional information. cc: File C:\Documents and Settings\cjk\Local Settings\Temporary Internet Files\OLK5D\Alternative 7.doc M EM O R A N D U M C:\ D o c u m e n t s a n d S e t t i n g s \ c j k \ L o c a l S e t t i n g s \ T em p o r a r y I n t e r n e t F i l e s \ O L K 5 D \ A l t e r n a t i v e 7 . d o c T AB L E A T EM E C U L A H OS P I T A L A LT E R N A T I V E 7 B UI L D -OU T S EG M E N T O PE R A T I O N S Bu i l d - o u t W i t h o u t P r o j e c t Bu i l d - o u t W i t h P r o j e c t Se g m e n t Ex i s t i n g R o a d w a y Cl a s s a LO S E Ca p a c i t y b Vo l u m e c V/ C d LO S e Vo l u m e c V/ C d LOS eV/C Δ Wi n c h e s t e r R o a d Di a z R d t o J e f f e r s o n A v e 4- L n M a j o r R d 34 , 1 0 0 29 , 0 0 0 0. 8 5 0 D 40 , 1 4 0 1. 1 7 7 F 0.327 Je f f e r s o n A v e t o I - 1 5 8- L n U r b a n A r t 71 , 8 0 0 45 , 0 0 0 0. 6 2 7 B 55 , 5 4 0 0. 7 7 4 C 0.147 Ra n c h o C a l i f o r n i a R o a d Di a z R d t o J e f f e r s o n A v e 6- L n U r b a n R d 53 , 9 0 0 18 , 0 0 0 0. 3 3 4 A 18 , 3 6 0 0. 3 4 1 A 0.007 Je f f e r s o n A v e t o I - 1 5 8- L n U r b a n A r t 71 , 8 0 0 39 , 0 0 0 0. 5 4 3 A 39 , 9 7 0 0. 5 5 7 A 0.014 Je f f e r s o n A v e No r t h o f W i n c h e s t e r R d 6- L n P r i n c i p a l Ar t 53 , 9 0 0 26 , 0 0 0 0. 4 8 2 A 26 , 6 1 0 0. 4 9 4 A 0.011 Wi n c h e s t e r R d t o O v e r l a n d D r 4- L n M a j o r R d 34 , 1 0 0 38 , 0 0 0 1. 1 1 4 F 38 , 6 1 0 1. 1 3 2 F 0.018 Ov e r l a n d D r t o R a n c h o C a l i f o r n i a R d 4- L n M a j o r R d 34 , 1 0 0 28 , 0 0 0 0. 8 2 1 D 28 , 6 1 0 0. 8 3 9 D 0.018 Di a z R o a d No r t h o f W i n c h e s t e r R d 4- L n M a j o r R d 34 , 1 0 0 15 , 0 0 0 0. 4 4 0 A 26 , 5 0 0 0. 7 7 7 C 0.337 Wi n c h e s t e r R d t o O v e r l a n d D r 4- L n M a j o r R d 34 , 1 0 0 23 , 0 0 0 0. 6 7 4 B 23 , 3 6 0 0. 6 8 5 B 0.011 Ov e r l a n d D r t o R a n c h o C a l i f o r n i a R d 4- L n M a j o r R d 34 , 1 0 0 11 , 0 0 0 0. 3 2 3 A 11 , 3 6 0 0. 3 3 3 A 0.011 Fo o t n o t e s : a. Ci t y o f T e m e c u l a R o a d w a y C l a s s i f i c a t i o n b. Ri v e r s i d e C o u n t y R o a d w a y C a p a c i t y c. Ci t y o f T e m e c u l a G e n e r a l P l a n U p d a te , C i r c u l a t i o n E l e m e n t T r a f f i c S t u d y . d. Vo l u m e / C a p a c i t y r a t i o e. Le v e l o f S e r v i c e