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A S S O C I A T E S I N C <br /> MW2, MW3, and CW were analyzed for TPHg, BTEX, and total lead Groundwater analytical <br /> results are summarized in Table 2, and laboratory data sheets are presented in Appendix E <br /> 1 <br /> 3.0 SUBSURFACE CONDITIONS <br /> 1 Soils encountered beneath the site consist primarily of clay with varying amounts of silt and sand <br /> to a depth of approximately 62 feet below grade, the maximum depth explored An apparent silty <br /> 1 sand lens was noted at a depth of approximately 115 to 15 feet below grade <br /> 1 Groundwater beneath the site was first encountered at approximately 25 0 feet below grade <br /> After well completion, the piezometric surface stabilized to approximately 22 5 feet below grade <br /> Based on March 26, 1998 monitoring data(Table 2), groundwater flows to the north-northeast at <br /> a gradient of approximately 0 02 ft/ft or 105 feet per mile A groundwater gradient map for <br /> March 26, 1998 is presented on Figure 3 <br /> 1 4.0 RESULTS <br /> 4_1 Soil <br /> 1 Petroleum hydrocarbons were detected in bonngs ASB1, MW5, MW6, MW7, SBS, and SB9 <br /> Elevated concentrations of petroleum hydrocarbons were detected in borings ASB1 and SB8 <br /> between 15 feet and 30 feet bgs and attenuate rapidly with depth Soil samples collected from <br /> 1 borings MW6, MW7, and SB9 contained low concentrations of toluene, ethylbenzene, xylenes, <br /> and TPHg Only one sample from boring MW5 contained a trace amount of ethylbenzene <br /> ' Oxygenate fuel additives were not detected in any soil samples, but several samples had elevated <br /> detection limits due to dilution factors Lead was detected in soil samples collected from borings <br /> ' ASBI, MW5, MW6, SB8, and SB9 The lead concentrations were consistent with background <br /> concentrations of lead for the San Joaquin Valley(less than 15 ppm) <br /> 1 These data indicate that residual impacted soil from the former unleaded gasoline tanks exists in <br /> shallow soils and within the capillary fnnge The vertical extent of impacted soil has been limited <br /> 1 to less than 45 feet bgs, based on the analytical results from boring SB8 which was advanced <br /> through the location of the former UST pit A site map showing cross section locations is shown <br /> on Figure 4 Cross sections are shown on Figures 5 and 6 The horizontal extent of residual <br /> ' impacted soil from the unleaded gasoline tanks has been defined to north and west of the former <br /> UST pit <br /> w 162596Veporls\plutpsj doc 5 <br />