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During the drilling operations, the geologist maintained a log of <br /> the materials encountered. Soil samples were field screened for <br /> the presence of total volatile organic (TVO) vapors using a <br /> handheld PID equipped with a 10. 2 EV lamp. <br /> Preservation of Soil Samples <br /> After field screening, the sample sleeve ends were sealed with <br /> aluminum foil and further protected with plastic caps. The samples <br /> were labeled with ID#, location, depth, date, time, sampler's <br /> initials, and analyses to be performed; then placed in an ice chest <br /> at 40C and delivered with accompanying chain of custody <br /> documentation to a California State certified analytical <br /> laboratory. <br /> Selection and Certified Laboratory Analyses of Soil Samples <br /> A determination of which soil samples from each soil boring were to <br /> be selected for certified laboratory analysis, was made based on <br /> the results of field screening. A minimum of one sample, per <br /> borehole from 15 feet below surface was analyzed. The selected <br /> soil samples were analyzed by a certified laboratory for <br /> concentrations of Total Petroleum Hydrocarbons as Gasoline (TPHg) <br /> using EPA method 8015 modified, 5030 extraction, and Benzene, <br /> Toluene, Ethylbenzene, and Xylenes (BTEX) using EPA method 8020. <br /> Select samples were also analyzed for TPH diesel (TPHd) using EPA <br /> method 8015 modified, 3510 extraction. <br /> Destruction of Confirmation Soil Borings <br /> The seven soil borings were destroyed by the drilling contractor on <br /> the same day they were drilled. The borings were backfilled from <br /> total depth to within two feet of the surface with neat cement with <br /> <5% bentonite. The surface portion of the hole was either plugged <br /> with quick setting concrete or clean soil dependent on surface <br /> cover, then leveled to grade. <br /> RESULTS <br /> During drilling, elevated PID readings were detected in soil <br /> borings SB1 and SB2 , (see Table 1) , with the highest level being in <br /> SB1 at 15 feet below surface. <br /> During drilling, the following general soil profile was <br /> encountered: <br /> 1. Silty sand from 1 to 5 feet below the surface. This <br /> sand is discontinuous and not found over the entire <br /> site. <br /> 2 . Dark brown silty clay, from the base of the silty sand <br /> to approximately 14 feet below the surface. <br /> 3 <br />