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I <br /> ' 1444 MARIPOSA ROAD <br /> WICA No 2938 06 <br /> September 6,2000 <br /> Page 4 <br /> Monitoring Wells <br /> On October 25, 1993, three soil borings (MWI,MW2 and MW3)were drilled with a truck- <br /> mounted Mobile B-61 drill ng equipped with 10-tech diameter hollow-stem augers Soil <br /> samples were collected from each boring at five-foot maximum intervals Selected samples were <br /> placed in an ice chest containing ice, and submitted under chain-of-custody to a California- <br /> certified laboratory for analysis of TPH as gasoline and BTEX <br /> ' The soil borings were subsequently converted into four-inch diameter groundwater monitoring <br /> wells (MWI,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 as gasoline, diesel motor oil and BTEX <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 TPH as gasoline Low <br /> but detectable concentrations of benzene were revealed in samples obtained from depths of 60 to <br /> ' 70 feet in monitoring well MWI and ethylbenzene was detected in the 70-foot sample from well <br /> MW2 <br /> ' Initial laboratory results for water samples collected from the wells revealed no detectable <br /> concentrations of TPH as gasoline, diesel, or motor oil However,benzene was detected in MW2 <br /> ' at a concentration of 1100 ug/l and total xylenes were detected in MW I at a concentration of <br /> 0.57 ug/l <br /> ' Additional Stockpile Soil Sampling <br /> ' The stockpiled soils generated during the original excavation were sampled a second tune on <br /> December 3, 1993 after approximately 13 months of aeration Analytical results for samples <br /> ' obtained from stockpile#1, located southerly of the excavation,revealed no detectable <br /> concentrations of TPH or BTEX Analytical results for samples obtained from stockpile#3 <br /> ' located northerly of the excavation,revealed an average TPH as gasoline concentration of 96 <br /> • mg/kg Stockpile#2 was generated during the construction of an access ramp and was therefore <br /> ' not sampled <br /> 000 <br /> WALLACE KUHL <br /> Re ycled ape &ASSOCIATES INC <br />