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Sampling Report—P. G.&E.,Stockton,C4 October, 2003 The analytical results for the two waste oil pipe trench samples were non-detectable for all of the analytes except for metals and tetrachloroethylene (PCE). All of the LUFT five metals except cadmium were detected in the samples at what appear to be naturally occurring background levels. PCE was detected in PI and P2 at concentrations of 0.0079 and 0.0055 ppm, respectively. The analytical data is summarized on Table 1. Copies of the laboratory data sheets and the chain of custody are attached to this report. The analytical results for the two unleaded gasoline dispenser samples were non-detectable for all of the analytes except for MTBE. MTBE was detected in UNL 1 and UNL 2 at concentrations of 1.5 and 0.0055 ppm, respectively. The analytical results of the sample collected from beneath the diesel dispenser was non-detectable for all of the analytes except for TPH as diesel and TPH as gasoline, which were detected at concentrations of 140 and 2.4 ppm, respectively. The analytical data is summarized on Table 2. Copies of the laboratory data sheets and the chain of custody are attached to this report. Environmental Screening Levels" (ESLs) for concentrations of contaminants in soils and groundwater have been established by the Regional Water Quality Control Board (RWQCB). The ESLs for the analytes encountered in the soil samples are shown on Tables 1 through 3. The ESLs from Table A assume that groundwater is a source of drinking water, and are therefore the most conservative screening levels for these compounds. The ESLs from Table B assume that groundwater is not a source of drinking water. All of the analytes from the two waste oil pipe trench samples are below both the residential and commercial ESLs. The occurrences of MTBE in samples UNL 1 and UNL 2, and of diesel in the sample from below the diesel dispenser, are above the ESLs from Table A, but below the ESLS from Table B. 3