Laserfiche WebLink
30 June 1995 <br /> AGE-NC-95-0101 <br /> Page 2 of 6 <br /> In January 1994, four soil borings were drilled at the site by Geological Audit Services, Inc <br /> (GeoAudrt) Two of the borings were completed as monitoring wells MW-5 and MW-6 to a depth <br /> of 85 feet Borings B7 and B8 were advanced to a depth of 65 feet and backfilled in the entire depth <br /> with Portland cement No petroleum hydrocarbons were detected in any of the 14 soil samples <br /> collected and analyzed from the borings or monitoring wells <br /> 2 3 GROUND WATER MONITORING <br /> Ground water monitoring at the site has been performed by AGS, Nations Groundwater Associates <br /> (NGA) and GeoAudit on ten occasions between June of 1987 and November 1994 Ground water <br /> flow direction has been consistently to the southwest Petroleum hydrocarbons were detected in <br /> groundwater samples from at least one monitoring well during each sampling event Analytical <br /> results of past and current ground water samples are included in Table 3 <br /> 2 4 UST REMOVAL <br /> 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 San Joaquin County Public <br /> Health Services-Environmental Health Division(PHS-EHD)records, approximately 800 cubic yards <br /> of gasoline-contaminated soil were removed from the tank excavation and stockpiled on-site <br /> In anticipation of future cleanup requirements, four-inch diameter slotted PVC casing was installed <br /> 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 the new USTs were <br /> installed over the plastic sheeting <br /> 3.0. PROCEDURES <br />' 3 1 DRILLING AND SAMPLING <br /> In a letter dated 30 March 1995, the PHS-EFID stated that "further soil and ground water <br /> characterization needs to be performed in the area of MW#2 to define contamination limits" <br /> Therefore, on 10 April 1995,two soil borings were dulled using a CME-55 drill ng The drill ng and <br /> two man crew were supplied by Soils Exploration Services, Inc (SES) of Benicia Boring B9 was <br /> installed approximately 20 feet northwest of MW-2 Boring B10 was installed approximately 9 feet <br /> west of the southern corner of the building on-site Boring Locations are shown on Figure 2 Boring <br />