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V L ATC A S S O C I A T E S I N C WW bgs consisted of silt, silty sand, sandy silt, and well graded sand. Soil from depths between 16.5 to 20 feet bgs and approximately 25.5 feet bgs consisted of lean clay with a layer of poorly graded sand encountered in boring MW3. Soil from depths between 25.5 feet bgs 26.5 to 31 feet bgs consisted of poor to well graded sand. Soil from depths between 26.5 to 31 feet bgs and 46.5 to 50 feet bgs consisted of lean clay and fat clay intermixed with elastic silt and silty sand. Soil from depths between 46.5 to 50 feet bgs and 51.5 feet bgs, the maximum depth explored, consisted of lean clay with sand and silty sand. 3.2 Hydrogeology Water level measurements were collected from wells MW1 through MW3, on March 17, 1999. Water levels ranged from 33.96 to 34.50 feet below the tops of the well casing elevations. The water level data were used to develop the groundwater elevation contour map (Figure 3). Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost aquifer beneath the site flowed towards the west-northwest. The average hydraulic gradient on March 17, 1999 was calculated to be 0.002 ft/ft or approximate 12 ft/mile. A summary of groundwater monitoring data is presented in Table 2. 4.0 ANALYTICAL RESULTS 4.1 Soil Analytical Results The soil sample collected from 35.5 feet bgs in boring MW2 contained nondetectable to very low concentrations of TPHg and BTEX constituents. The soil sample collected from 50.5 feet bgs in boring MW2 contained no detectable concentrations of TPHg or BTEX constituents. Soil samples collected from boring MW3 at 35.5 and 50.5 feet bgs contained no detectable V concentrations of TPHg or BTEX constituents. Oxygenate fuel additives were not detected in any samples from borings MW2 or MW3. Analytical results of soil samples are summarized in Table 1. 4.2 Groundwater Analytical Results V The groundwater sample collected from well MW1 contained detectable concentrations of TPHg and BTEX constituents. The groundwater sample contained TPHg and benzene at concentrations of 134 micrograms per liter (ppb) and 37.5 ppb, respectively. The groundwater sample collected from well MW 1 contained methyl tertiary butyl ether (MTBE) at a concentration of 25.1 ppb. No other oxygenate fuel additives were detected in the groundwater sample collected from well MW1. The groundwater sample collected from well MW2 contained toluene at a concentration of 0.655 ` ppb. No other BTEX constituents or TPHg were detected in the groundwater sample collected from well MW2. The groundwater sample collected from well MW3 contained no detectable concentrations of TPHg or BTEX constituents. The groundwater samples collected from wells wA 163 93\reports\sumLdoc 4 v