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20 May 1996 <br /> AGE-NC Project No 95-0101 <br /> Page 2 of 4 <br /> In January 1994, two monitoring wells (MW-5 and MW-6) and two soil bonngs (137 and BS) were <br /> drilled at the site by Geological Audit Services, Inc (GAS) Petroleum hydrocarbons were not <br /> detected in any of the 14 soil samples collected and analyzed from the bonngs or monitoring wells <br /> In April 1995 Ap two bonngs (B9 and B 10) were drilled at the site Organic vapors were detected in <br /> soil samples collected from boring B9 from depths of 25 to 70 feet below surface grade (bsg) at <br /> concentrations of up to 646 ppm Organic vapors and/or hydrocarbon odors were not detected in <br /> boring B10 TPH-g was detected in sample B9-35 at a concentration of 9,100 ppm Benzene and <br /> xylenes were detected in sample B9-45 at concentrations of 0 006 ppm Petroleum hydrocarbons <br /> were not detected in any other soil samples analyzed <br /> Groundwater samples were collected from the bottom of bonngs B9 and B10 TPH-g was detected <br /> in the water sample collected from boring B9 at a concentration of 300 ppb (parts per billion, <br /> reported as micrograms per liter) Only xylenes were detected in the water sample collected from <br /> boring B 10, at a concentration of 0 83 ppb <br /> Boring B9 was backfilled from 50 to 80 feet bsg then completed as vadose zone well VW-1, with <br /> slotted PVC casing from 30 to 50 feet Boring B 10 was backfilled over its entire depth with Portland <br /> Cement <br /> 2 3 GROUND WATER MONITORING <br /> 1 Ground water mon tonng at the site has been performed by AGS, Nations Groundwater Associates <br /> (NGA), GeoAudit and AGE on twelve occasions between June of 1987 and August 1995 Ground <br /> water flow direction has been consistently toward the southwest Analytical results of the past and <br /> current ground water samples are included in Table 2 <br /> 2 4 UST REMOVAL <br /> I Four USTs were removed from the site in March of 1990 Low concentrations of volatile aromatics <br /> were detected in soil samples collected beneath the tanks According to records on file with the PHS- <br /> EHD, approximately 800 cubic yards of gasoline-contaminated soil were removed from the tank <br /> 1 excavation and stockpiled on-site <br /> In anticipation of future cleanup requirements, four-inch diameter slotted PVC casing was installed <br /> 1 around the bottom of the excavation Approximately 5 inches of pea gravel were placed in the <br /> excavation to cover the piping Plastic sheeting was placed over this gravel, and new USTs were <br /> installed over the plastic sheeting <br />