ARCHIVED REPORTS_VAPOR INTRUSION SURVEY - SOIL GAS SAMPLING REPORT

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' 3.0 VAPOR INTRUSION SURVEY SUMMARY AND CONCLUSION PSC submitted the Vapor Intrusion Survey — Soil Gas Sampling Work Plan (Work Plan) on September 30, 2008 in accordance with the August 15, 2008 CVRWQCB request. The CVRWQCB approved the Work Plan in a letter dated October 2, 2008. The field activities were performed on January 30, 2009. A summary of the activities and the resultant data are as follows: • PSC collected eight soil gas samples identified as SG-1 through SG-7 and SG-1 DUP; • The building on site is an approximate 10,500 square-foot single story concrete slab on grade with no basement or crawl space; • The first of eight sample locations was SG-Test located in the former UST excavation source area and was used to test the appropriate purge volume to be removed prior to collecting the subsequent soil gas samples for analytical testing; • Sample SG-1 was also located in the source area. Sample SG-2 was located inside the on-site building. Samples SG-3 through SG-7 were located on the exterior perimeter of the building on the west, north, and east sides; 1 • For each sampling location, the sample train was leak checked and purged prior to collecting the soil gas sample; • Sample SG-4 was disqualified as unusable, due to low sample volume being collected; • The IPA analytical results indicate that all samples were successfully collected without reporting the presence of IPA. This confirms that the sampling trains were intact and that no ambient air infiltrated the sample canisters; • TPH-g and some or all of the BTEX constituents were reported among the samples. The TPH-g concentrations ranged from 680 pg/m3 in sample SG-2 to 5,500 µg/m3 in sample SG-3; ' • None of the reported concentrations for TPH-g or BTEX exceeded the SFBRWQCB ESLs for vapor intrusion of residential buildings; and • There were no reported concentrations for any of the fuel oxygenates or the fuel additives among the samples. None of the reported concentrations for BTEX, fuel oxygenates, or fuel additives exceeded the SFBRWQCB ESLs for Residential Shallow Soil Gas. The only TPH-g exceedence was for sample SG-4, which was deemed an unusable sample. In addition, the reported TPH-g ' value (18,000 µg/m3) was still less than the SFBRWQCB ESL for Commercial Shallow Soil Gas (29,000 µg/m3). The building on the subject property is a commercial building used as a warehouse by the property owner. Therefore, the risk of soil vapor intrusion does not exist ' for the facility. Vapor Intrusion Survey Soil Gas Sampling Report prepared For.Sam Lee Bakery Gmup, - Prepared By:PSC Industrial Outsourcing,LP Sara Lee—Lincolcoin Sneer\2009_03_311-Soil Gas Sampling Report.doc March 31,200909 12