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a A S S Q C I A T E S I N C 3.0 SUBSURFACE CONDITIONS ' 3.1 Geology ' Soil in boring MW1 consisted of lean clay (CL) from the surface to between and 21 5 and 25 feet bgs Poorly graded sand (SP) was observed from between 215 to 25 feet and 26 5 to 30 feet bgs ' followed by alternating layers of slit and clay to depths between of 41 to 45 feet bgs The remaining soil profile consisted primary of sand with varying amounts of fines (SM to SC) to 62 feet bgs, the maximum depth explored 3.2 ffydrogeology A water level measurement was collected from well MW 1 on February 26, 1999 The water level was measured at 54 84 feet from the top of the well casing A summary ofg roundwater monitoring data is presented 1n Table 2 The site's underlying groundwater gradient could not be determined with a single measurement point, however regional groundwater flow is estimated to be eastward based on San Joaquin County Flood Control and Water Conservation District data (Lynes of Equal Elevation of Groundwater, Fall 1997) ' 4.0 ANALYTICAL RESULTS 4.1 Soil Analytical Results Soil samples collected from boring MW i at depths of 20 5 and 25 5 feet bgs contained ' concentrations of TPHg [179 and 272 parts per million (ppm)] toluene (0 284 ppm), � ethylbenzene (1 42 to 1 70 ppm), and total xylenes (10 7 to 113 ppm) Only the sample collected from at 55 5 feet bgs contained MTBE (0 00752 ppm) Benzene and the remaining fuel oxygenates were not detected above laboratory method detection limits in any samples Analytical results of soil samples are summarized 1 Y p n Table 1 ' 4.2 Groundwater Analytical Results ' The groundwater sample collected from well MW1 did not contain concentrations of TPHg, benzene, toluene, or ethhlbenzene above laboratory method detection limits of 50 parts per billion (ppb), and 0 50 ppb, respectively However, total xylenes (3 8 ppb) and oxygenate additive-lM=i-BE (51--4-ppb) were detected w 1112921reportsl,wnwel doc 4 1