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S E C 0 R Circle K Store 08671 August 31, 2005 Page 2 i 21 tons of petroleum-impacted soil were over-excavated from the site and disposed of at Forward Landfill On January 27 and 28, 1999, four groundwater monitoring wells (MW-1 through MW-4) were installed onsite by SECOR The results of this work are documented in SECOR's report titled Well Installation Report, dated March 16, 1999 Since their installation, the four wells have been monitored and sampled quarterly On December 12th through 14th, 2001, one deep soil boring (SB-1) was drilled to an approximate depth of 63 feet below ground surface (bgs) and three additional groundwater monitoring wells (MW-5, MW-6, and MW-7) were installed onsite by SECOR The results of this work are documented in SECOR's report titled Site Assessment Report, dated June 21, 2002 In November 2003, SECOR installed deep well MW-8, MW-9, and MW-10 at the site Petroleum hydrocarbons were not reported in soil and groundwater samples form the new wells Vertical and lateral delineation of the plume has been completed SECOR performed a sensitive receptor survey to identify the location of permitted water supply wells within a 2,000-foot radius of the site The sensitive receptor survey consisted of reviewing the California Department of Water Resources (DWR) files for locating water supply wells in the area, contacting the local water purveyor (San Joaquin County), and a conducting a door-to-door field survey in search of any wells or other sensitive receptors within 1,000 feet of the site Four wells were identified within the surveyed area, one municipal well and three domestic wells The domestic well was identified as Colonial Heights municipal water supply well #3 (Well DW-3) The location of Well DW-3 was verified in the field and surveyed, and is situated 260 feet south of the site, on the south bank of Mosher Slough, which borders the intersection of Thornton Road and Davis Road Three additional water supply wells in the area were identified One well was identified at Bear Creek Veterinarian Hospital (Well DW-2), located at 8728 Thornton Road Well DW- 2 is located 444 feet north of the site Another well is located at a residence (Well DW-4), located at 8732 Davis Road (180 feet north of the site) SECOR field staff located what appeared to be a domestic water supply well (Well DW-1) on the property located at 8855 Thornton Road and is 281 feet northwest of the site The resident was not available to confirm the existence of the well, and a well survey form was not completed by the property owner, however, the possible domestic well was housed in a similar enclosure as the previously identified wells in the field Based on TRC's Quarterly Monitoring Report dated March 1, 2005, maximum TPPH and MtBE concentrations were 52 ppb (MW-10) and 10,000 (MW-4), respectively Groundwater flow direction in both the shallow and deep zone was to the east COMPLETED SCOPE OF WORK SECOR supervised the installation of two soil vapor extraction (SVE) wells followed by the completion of a SVE pilot test designed to test the effectiveness of soil vapor extraction . (SVE) as a method to remediate petroleum hydrocarbon contamination in soil beneath the