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k ly 26 April 2011 AGE-NC Project No. 95-0104 Page 7 of 12 Ground water samples collected from the domestic ,well located approximately one hundred-fifty to two-hundred feet south (downgradient), of the former UST area in April 1993 contained substantial halogenated volatile organic compounds. As a result, use of the domestic water well was discontinued in April 1993..,In July 1996, the well was sealed and capped under a San Joaquin County permits (Figure 7). In addition, AGE representatives observed 58 private domestic water well within a 2,000-foot radius of the site. ,F A domestic water well receptor is located approximately 250 ifeet northeast of the site in the down gradient direction at 4716 East Waterloo Road(DW-11). Between November 2008 and August 2010, five ground water sampling events were performed at DW-1; ground water samples were collected and analyzed for 1,2-dichloroethane (1,2-DCA). 1,2-DCA was not detected above laboratory reporting limits during any of the sampling events (Table 3). p Drinking water at and near the site is currently provided[by the City of Stockton municipal wells. California Water Service Company(Cal Water) maintains a municipal well and tank 'I approximately 2,000 feet north of the site between East Waterloo Road and Cherokee Road. No other municipal wells maintained by the City of Stockton or Cal Water are located within 2,000 feet of the site. First encountered ground water may not be used for drinking, due the EHD sanitary well seal requirements. A well survey map, depicting all observed water wells is reseip,ted in Figure 7. Information obtained from the survey is summarized in Table 4. Vllell construction information was obtained from the State of California Department of Water Resources and interviews with property owners and tenants. . i x a� E F 4.0. SOIL AND GROUND WATER CORRECTIVE ACTION Between 18 March and 16 April 1999, a soil vapor extraction (SVE) pilot test was initiated at the site by applying a vacuum at well VW-1.The volume of hydrocarbons extracted from VW-1 between 18 March and 16 April 1999 was calculated to be approximately 81 gallons of petroleum hydrocarbons. Between 22 July and 14 December 1999, a SVE pilot test was continued at the site. The volume of hydrocarbons extracted from VW-1 between 22 July 1999 and 14 December 1999 was calculated to be,,' approximately 77.92 gallons of petroleum hydrocarbons. AGE estimated that operation of the SVE system removed approximately 158.92 gallons of petroleum hydrocarbons formerly impacting soil at the site. An IAS pilot test was also conducted by connecting an air compressor to the well-head at r MW-6. Compressed air was supplied to well MW-6 at an approximate pressure of 10 i pounds per square inch (psi). Approximately 5 psi was required to overcome the water i' column in the sparging wells. Air sparing continued until the end of December 1999. 1 Advanced GeoEnvironmental,Inc. a I ,11