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bgs Benzene concentrations also exceeded EPA's Preliminary Remediation Goal (PRG) for benzene concentrations in soils in industrial areas The sample was also analyzed for TOC and HPC The results of the analyses were 1,600 mg/kg and 5,000 colony-forming units/gram (CFU/g), respectively ' Former Tank Site #2. Analytical results for soil samples collected at Former Tank Site #2 are provided in Table 4-2 and summarized on ' Figure 4-4 TPH as gasoline and BTEX were detected in one or more samples collected from borings S2-B1 and S2-B4 (located on or near the sidewall of the former excavation area) and boring S2-B3 (located ' within the warehouse building) Samples collected from boring S2-B2 did not contain detectable TPH or BTEX concentrations The TPH concentration detected in the shallowest soil sample collected from ' S2-B1 was low (i e , did not exceed the cleanup goal), and the soil sample collected approximately 6 5 feet deeper did not contain detectable TPH concentrations The 100 mg/kg TPH cleanup goal was ' exceeded in four soil samples collected from S2-B3 and S2-B4, these exceedances are discussed below tTwo samples collected from boring S2-B3 exceeded the 100 mg/kg cleanup goal for TPH. The samples were collected at depth intervals above or at the top of the silty clay layer that is present from 8 to 13 ft bgs This silty clay layer appears to function as a confining layer for ground water underlying the site TPH concentrations in the sample collected from a depth interval below the confining layer were less than the 100 mg/kg cleanup goal Two samples collected from boring S2-B4 exceeded the 100 mg/kg cleanup goal for TPH. The samples were collected at depth intervals above the silty clay confining layer TPH concentrations decreased with ' depth to nondetectable at 15 feet bgs The shallowest sample collected from boring S2-B4 was also analyzed for TOC and HPC The results of the analyses were 3,300 mg/kg and 1,000 CFU/g, respectively ' n r ate Chemis�X ' Ground water samples were analyzed quarterly for purgeable hydrocarbons by EPA Method 8015 Modified and BTEX by EPA Method ' 8020 In addition, early sampling events (April 1991 through June 1992) included organic and total lead and ethylene dibromide analyses The ground water analyses were performed by Sequoia at their facility in Concord, California and by Anametrix Laboratoy (San Jose, CA) These analyses were performed according to the published EPA- approved procedures, including adherence to specified holding times 4-6