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' 1 2 2 Remediation System Operation and Confirmation Sampling <br /> From June 1999 through June 2000, ENSR operated a soil vapor extraction (SVE) system at the <br /> site Initially, ENSR extracted from VW-1 D, VW-1 S, VW-2S, VW-3, and VW-4 After several <br /> months of operation, air sparging was initiated in MW-1 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 have <br /> operating water wells These properties include the San Joaquin Catholic Cemetery (site), St <br /> Joseph's Hospital, and a residential dwelling at 1821 North Hunter Street The locations of the <br /> wells on the cemetery and hospital properties are shown on Figure 3 <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 /> was almost completely remediated by the SVE system <br /> To delineate the vertical extent of impacted groundwater, discrete groundwater samples were <br /> collected at approximately 75, 90, and 125 feet bgs from a cone penetration test (CPT) soil <br /> boring (CPT-1) located approximately 20 feet northeast (downgradient) of the former USTs The <br /> discrete groundwater sample results indicated that the vertical extent of impacted groundwater <br /> was mostly delineated Concentrations of methyl tertiary butyl ether(MTBE) declined <br /> significantly with depth and were not present in the 125-foot groundwater-bearing interval Only <br /> 1,2-dichloroethane (1,2-DCA)was detected in the 125-foot groundwater sample, at a low <br /> concentration of 0 5 micrograms per liter(µg11) These groundwater analytical results are <br /> summarized in Table 3 <br /> 1 i 6 <br /> 1 <br />