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12sm <br /> GEOMATRIX <br /> additional soil sampling on behalf of CPL on 19 September 1996. Geomatrix advanced one <br /> soil boring (SB-1) at the former location of test pit E (where the highest concentration of TOG <br /> and TRPH were previously detected) and collected soil samples at 4, 10, and 15 feet bgs for <br /> laboratory analysis of total extractable petroleum hydrocarbons as crude oil (TEPH) using EPA <br /> Method 8015M quantified against a San Joaquin Valley crude standard provided by CPL. <br /> Findings of this investigation are described in the 11 December 1996 Geomatrix report titled, <br /> Soil Assessment Results, Hanson Property, 7750 Schulte Road, Tracy, California. No <br /> petroleum hydrocarbons were detected in the samples collected at 10 and 15 feet bgs. In the <br /> sample collected at 4 feet bgs, a small amount of high-boiling organic material (C20 to >C40 <br /> carbon range)was present(Table 2). However, a comparison of the chromatogram of the <br /> material to those of a crude oil standard indicated that no crude oil or Bunker C oil was present. <br /> Based on these findings, Geomatrix concluded that former pipeline operations did not provide a <br /> source of petroleum constituents to the soil at the Hanson Property and that no further soil or <br /> groundwater assessment was necessary. <br /> 3.0 ADDITIONAL ASSESSMENT—FIELD AND ANALYTICAL METHODS <br /> Based on his review of the 11 December 1996 report, Mr. Michael Infurna of PHS-EHD, in a <br /> verbal communication with CPL, requested additional soil and groundwater sampling be <br /> conducted to confirm that the subsurface "pipe wrap" material did not provide a source of <br /> petroleum hydrocarbon constituents to soil or groundwater. This request resulted in a series of <br /> additional assessments of soil and groundwater quality. In March 1997, two soil samples and <br /> one grab groundwater sample were collected and analyzed for petroleum hydrocarbons. In June <br /> 1997, a temporary well was installed and soil and groundwater samples were collected and <br /> analyzed to confirm results of the grab groundwater sample collected in March 1997. The <br /> PHS-EHD requested that an additional groundwater sample be collected from the temporary <br /> well approximately 30+days from the June 1997 sampling event. <br /> 1AWPD0CS\4097ADDLINVB.D0C 3 <br />