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1444 MARIPOSA <br /> WKA No. 2938.03 <br /> February 1, 1996 <br /> Page 3 <br /> October 1993 <br /> Three soil borings (MW1, MW2 and MW3) were drilled with a truck-mounted Mobile B-61 drill <br /> rig equipped with 10-inch diameter hollow-stem augers. Soil samples were collected from each <br /> boring at five-foot maximum intervals. Selected samples were placed in an ice chest containing <br /> ice, and submitted under chain-of-custody to a California-certified laboratory for analysis of <br /> TPHg using Modified EPA method 8015 and BTEX using EPA method 8020. <br /> The soil borings were subsequently converted into four-inch diameter ground water monitoring <br /> wells (MW1, MW2 and MW3). Water samples were obtained from the wells and were <br /> immediately placed in an ice-chest containing ice and submitted under chain-of-custody to a <br /> California-certified laboratory for analysis of TPH using EPA method 8015 and BTEX using <br /> EPA method 8020. <br /> Laboratory analytical results of the soil samples collected during the installation of the three <br /> ground water monitoring wells revealed no detectable concentrations of TPHg. Low but <br /> detectable concentrations of benzene were detected in samples obtained from depths of 60 to 70 <br /> feet in monitoring well MW1 and ethylbenzene was detected in the 70 feet sample from well <br /> MW2. <br /> Laboratory analytical results of water samples collected from the wells revealed no detectable <br /> concentrations of TPH as gasoline, diesel, or motor oil. However, benzene was detected in <br /> MW2 at a concentration of 1100 µgIf and xylene was detected in MW1 at a concentration of <br /> 0.57 µgI f. <br /> December 1993 <br /> The stockpiled soils generated during the original excavation were sampled a second time on <br /> December 3, 1993. Analytical results for samples obtained from stockpile #1, located southerly <br /> of the excavation, contained no detectable concentrations of TPH or BTEX. Analytical results <br /> L for samples obtained from stockpile #3 located northerly of the excavation, revealed an average <br /> WALLACE•KUHL <br /> Recycled paper SASSOCLO ES INC. <br />