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drilling boreholes at 96 <br /> Predetermined <br /> based on the grid pattern shown ein�FigureC5. The <br /> Proposed sampling area has been divided into five <br /> sampling sections, each containing at least nine <br /> grid areas of approximately 256 square feet each. <br /> Soil borings will be drilled utilizing 6- or <br /> 8-inch-diameter, continuous-flight, hollow-stem <br /> augers. To avoid cross-contamination, the augers <br /> will be steam-cleaned prior to drilling each boring. <br /> Soil samples are to be obtained for soil <br /> description, field hydrocarbon vapor testing, and <br /> laboratory analysis. The sampling program is <br /> designed to determine the contaminant level at two <br /> depth intervals: from ground surface to 5 feet below <br /> grade and from 5 to 10 feet below grade. Two <br /> discrete samples will be collected from each depth <br /> interval at each borehole as follows: <br /> o From ground surface to 5 feet, samples will be <br /> collected at 2 feet and at 9 .5 feet below grade. <br /> o For the 5- to 10-foot depth interval, samples <br /> will be collected at 7 feet and at 9.5 feet below <br /> grade. <br /> Since the vertical extent of soil contamination is <br /> limited by the water-bearing zone to grade <br /> approxima <br /> x 10 feet below , <br /> no samples will be collectely <br /> ted <br /> below the 10-Foot depth. <br /> Soil samples will be retrieved ahead of the lead <br /> auger utilizing an 18-inch-long by 2-inch7diameter, <br /> Split spoon sampler lined with 1 .5-inch-diameter, <br /> stainless steel sample tube inserts. The sampler <br /> and sample tubes will be washed with a sodium <br /> tripolyphosphate solution and rinsed before each <br /> sampling event. The sampler will be driven by the <br /> 30-inch free fall of a 190-pound hammer. Blow <br /> counts will be recorded for three successive 6-inch <br /> intervals, <br /> Upon retrieval from the sampler, the sample tubes <br /> will be removed and securely sealed with Teflon <br /> sheeting :and polyurethane caps. The bottom sample <br /> tube is removed and capped; the -sample labeled with <br /> sample identification, sample depth, gdoiogist's <br /> 3 <br /> F4 <br />