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Working to Restore Nature <br /> LIMITED SUBSURFACE INVESTIGATION <br /> Field work at the site was conducted in accordance with our Work Plan dated September <br /> 23, 1993 and our Site Safety Plan dated October 19, 1993 Our field methods are described <br /> in the attached Field Procedures <br /> Field Work <br /> On October 22, 1993, a RESNA field geologist observed Westex Drilling of West <br /> Sacramento, California, drill one soil boring (B-5) near boring B-4 The boring was drilled <br /> to approximately 60-1/2 feet below grade The location of the boring is shown on Plate 2 <br /> The geologist collected soil samples at approximately 5 foot intervals for possible laboratory <br /> analyses and to characterize the geology beneath the site Soil was identified using visual <br /> and manual methods and classified according to the Unified Soil Classification System (Plate <br /> 3) Sediments encountered during drilling consisted predominantly of sand and clayey silt <br /> with trace silt and fine gravel as shown on the attached Log of Boring (Plates 4 through b) <br /> Groundwater was not encountered <br /> Drill cuttings are stored onsite Our geologist collected soil samples (one composite) from <br /> the stockpile for soil characterization We understand BP will remove the drill cuttings for <br />. disposal <br /> Analytical Methods <br /> The soil samples from 36 5, 46 5, 515 and 60 5 feet below surface grade (bsg) and the <br /> composite from the stockpile were analyzed for TPHg using modified Environmental <br /> Protection Agency (EPA) Method 8015M and benzene, toluene, ethylbenzene, and total <br /> xylene isomers (BTEX) using EPA Method 8020 The sample from the drill cuttings was <br /> also analyzed for lead using EPA Method 6010/200 7, ICP and reactivity, corrosivity, and <br /> ignitability Laboratory analyses were performed at PACE Incorporated in Novato, <br /> California (Hazardous Waste Testing Laboratory No 1282) <br /> Analytical Results <br /> Results of laboratory analyses of samples from the boring indicated concentrations of TPHg <br /> were below laboratory detection limits BTEX compounds were detected in the soil sample <br /> collected at a depth of 46 5 bsg and benzene was detected in the sample from 515 feet bsg <br /> BTEX compounds were not detected in the other soil samples Benzene concentrations were <br /> 0 150 and 0 0093 parts per million Results of analyses are shown in Table 1 <br /> 1117shoo/123013 01 2 <br />