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' 11369 NORTH HIGH' 99 • <br /> Project No 1001 <br />' August 28, 1997 <br /> • Page 5 <br /> Soil and Ground Water Conditions <br /> Soil conditions beneath the site include a brown silty sand and clayey silt to a depth of 8 to 10 <br />' feet, underlain by sandy silt and silty sand to 91 feet, the total depth of boring B l 0/MW 1 <br /> Interbedded fine to coarse grained sand from one to seven feet thick were encountered at <br />' <br /> various depths Geologic cross-sections A-A' and B-B' detailing the stratigraphy encountered <br /> beneath the site are provided as Figures 4 and 5 Cross-section lines are located on Figure 3 <br />' Ground water was encountered beneath the site at approximately 78 feet below grade in well <br /> MW1 and 79 feet in the domestic production well Regional ground water was expected to be <br />' encountered at a depth of approximately 80 feet below grade and flow to the east-southeast, <br /> based on review of the Lines of Equal Elevation of Ground Water, Fall 1994 Map prepared by <br />' the San Joaquin County Flood Control and Water Conservation District <br /> FINDINGS <br /> 1 Analysis of samples obtained from bonngs B2, B4, B7, B8, B9, B10, and BI I revealed TPH <br /> as gasoline concentrations ranging from not-detected (<0 005 mg/kg) to 1,400 mg/kg, and <br />' BTEX concentrations ranging from 0 0091 mg/kg to 15 mg/kg Analysis of samples obtained <br /> from borings B1, B3, B5, and B6 revealed no detectable TPH as gasoline or BTEX <br />' concentrations Analysis of sample B2-S6 collected from a depth of 32 5 feet revealed a trace <br /> lead concentration of 10 mg/kg (considered within background levels) and no detectable <br />' volatile halocarbons, with the exception of trace dichloromethane at 0 018 mg/kg The testing <br /> laboratory indicated the dichloromethane was likely a laboratory artifact generated during <br />' laboratory sample preparation and testing <br />' Analysis of the hydropunch ground water sample (B 10-W) and the monitoring well sample <br /> (MWI) revealed TPH as gasoline concentrations of 3,400 ug/1 and 700 ug/l, respectively, and <br /> benzene concentrations of 590 ug/1 and 700 ug/l, respectively The sample collected from the <br />' domestic production well revealed no detectable concentrations of TPH as gasoline or BTEX <br />