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NOW, `J �� Cardno` November 3,2014 ATC Glover Well Destruction Report Shaping the future Groundwater monitoring wells MW-7 and MW-8 were installed at the site on January 10 and 17, 2005. These wells were installed to provide lateral definition of the impacted groundwater plume down-gradient from former USTs. Six additional soil borings (GP-4 through GP-9)were advanced at the site to provide source area characterization and fill data gaps down-gradient from the identified source area on September 13, 2007. Analytical results confirmed that elevated concentrations of petroleum hydrocarbons remain in soil and groundwater beneath the site. Two in-situ soil vapor probes(VP-1 and VP-2)were advanced to collect soil vapor for laboratory analyses on September 14, 2007. Analytes detected in the soil vapor samples exceeded a hazard index of 1.0 (estimated site value of 1.6), the one-in one-million (1.OE-06) excess cancer risk for residential receptors (estimated site value of 1.79E-04), and the one-in-one hundred- thousand (1.OE-05) excess cancer risk for commercial receptors(estimated site value of 1.79E-04). As a result, recommendations were provided to implement a remedial plan at the site. ATC supervised the installation of groundwater monitoring well MW-9, three dual phase extraction wells (DP1 through DP3), and two air sparge wells (AS1 and AS2) between August 31 and September 2, 2009. The wells were installed to facilitate remediation pilot testing activities at the site. Pilot testing activities that included high vacuum dual phase extraction (HVDPE) and air sparging combined with soil vapor extraction (AS/SVE) between January 19 and August 19, 2010. In April 2012, SJCEHD requested that ATC reevaluate the soil vapor risk calculations for the site. Results of the revised risk assessment led SJCEHD to direct that further evaluation of soil vapor risks be performed at the site. 1.2 Sensitive Receptors ATC Associates, Inc. conducted a sensitive receptor survey (SRS)within a 2,000-foot radius of the site in 2009. Information regarding the SRS was submitted ATC's Sensitive Receptor Survey Report for Former Fayette Manufacturing, 7675 West 11`h Street, Tracy, California dated November 18, 2009. A summary of the SRS is provided below. Groundwater well construction logs of wells located within 2,000 feet of the site were obtained from the Department of Water Resources (DWR) and San Joaquin County PHS/EHD groundwater well construction logs and reviewed. Seventeen wells were identified within 2,000 feet of the site. Fifteen of these wells were identified through a site vicinity reconnaissance, and construction details are not available for them. These wells were all observed to be associated with residential,-commercial, or industrial properties, predominantly located to the south and west of the site. One potential well, associated with a large tank and identified as"NEI Reservoir", located to the northeast of the site on North Chrisman Road, appeared to be associated with water supply to a larger area. The tank supplies water to the North East Industrial Area of Tracy, located north of the site beyond the Southern Pacific Railroad tracks. Two pump house structures were observed, but the presence of a well could not be confirmed during the site reconnaissance. 3