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1 From June 1999 through June 2000, ENSR operated a sod vapor extraction (SVE) system at the <br /> • site Initially, ENSR extracted from VW-1D, VW-1S, VW-2S, VW-3, and VW-4 After several <br /> ' months of operation, air sparging was initiated in MWA According to ENSR, the remediation <br /> system removed over 7,000 pounds of gasoline hydrocarbons from the subsurface In July <br /> 2000, ENSR decommissioned the system and removed the equipment from the site <br /> ' On November 28 2000 Ramage Environmental published Environmental Site Investigation <br /> Report documenting the results of a sensitive receptor survey and the drilling of confirmation soil <br /> borings <br /> According to available records, three property parcels within 2,000-feet of the site had operating <br /> water wells These properties included the San Joaquin Catholic Cemetery (site), St Joseph's <br /> ' Hospital, and a residential dwelling at 1821 North Hunter Street <br /> To confirm the effectiveness of remediation efforts, soil samples were collected every 10 feet to <br /> a total depth of 100 feet directly beneath the former USTs The soil sample results indicated <br /> that except for 560 milligrams per kilogram (mg/kg) of Total Petroleum Hydrocarbons (TPH)-as- <br /> gasoline in soil at a depth of approximately 10 feet below ground surface (bgs), the vadose zone <br /> soil was remediated by the SVE system <br /> To delineate the vertical extent of impacted groundwater, discrete groundwater samples were <br /> collected with a cone penetration test (CPT) rig at 75, 90, and 125 feet bgs from soil borings <br /> 1 located approximately 20 feet northeast (downgradient) of the former USTs The discrete <br /> groundwater sample results indicated that the vertical extent of impacted groundwater was <br /> mostly delineated Concentrations of MTBE declined significantly with depth and were absent in <br /> ' the 125-foot groundwater-bearing interval Only 1,2-dichloroethane (1,2-DCA) was detected in <br /> the 125-foot groundwater sample, at a low concentration of 0 5 micrograms per liter (µg/l) <br /> ' On May 2, 2002, Ramage Environmental published Report, Additional Site Investigation, which <br /> documented the drilling of CPT borings for discrete groundwater sampling at six additional <br /> ' locations, and the installation of a two-well monitoring well cluster (MW-8A and MW-8B) The <br /> results of the project indicated that the extent of MTBE was defined and limited to the <br /> ' groundwater table northeast (downgradient) of the former UST Only low concentrations (0 5 to <br /> 1 2 µg11) of 1,2-DCA were detected in the 110 to 125 foot groundwater-bearing interval south and <br /> west of the former UST <br /> 4 <br />