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1 <br /> 1444 MARIPOSA ROAD <br /> WKA No 2938 05 <br /> August 26, 1999 <br /> ' Page 14 <br /> Water samples were obtained from the wells through the pump and tygon tubing and decanted <br /> ' into appropriate sample containers provided by the laboratory The water samples were <br /> immediately placed in an ice chest containing ice and submitted with chain-of-custody <br /> documentation to a California-certified laboratory for chemical analysis of TPH as gasoline <br /> using modified EPA Method 8015, BTEX using EPA Method 8020, and MTBE, DIPE, ETBE, <br /> TAME, Tert-Butanol, methanol, and ethanol using EPA Method 8260B <br /> Findings <br /> Soils <br /> Laboratory analysis of eight soil samples obtained from borings MW4 through MW7 revealed no <br /> detectable concentrations of petroleum hydrocarbons or oxygenates in soil Trace concentrations <br /> ' of benzene (0 0074 mg/kg) and MTBE(0 011 mg/kg), however, were reported in soil sample 135- <br /> 9I obtained from boring B5 at a depth of 82 feet Additional samples obtained from boring B5 at <br /> depths of 90 and 95 feet revealed no detectable concentrations of the above analytes Results of <br /> laboratory analysis for soil samples obtained from borings B5 and MW4 through MW7 are <br /> included in Tables 1 and 2 <br /> Groundwater <br /> The groundwater flow direction calculated from measurements obtained during the most recent <br /> ' groundwater sampling event on June 16, 1999 was revealed to be toward the southeast with a <br /> hydraulic gradient of 0 008 feet/foot A rose diagram is presented on Plate No 5 and is a <br /> graphical representation of the groundwater flow direction and gradients measured at the site <br /> during the past five years <br /> ' Laboratory analysis of the most recent groundwater samples obtained on June 16, 1999 revealed <br /> trace concentrations of TPH gasoline in two of the four new wells MW4 (63 ug/1) and MW5 (52 <br /> ug/l) None of the previously existing wells MWl through MW3 revealed detectable <br /> concentrations of gasoline though MW2 did revealed a benzene concentration of 2 6 ug/1 In <br /> ' addition, trace concentrations of the fuel oxygenate MTBE were identified in wells MW3 (0 81 <br /> ug/1) and MW4 (0 51 ug/1) <br /> I <br /> WALLACE KUHL <br /> Recycled paper Er ASSOCIATES INC <br />