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1 ' <br /> 3 0 RESULTS OF THE INVESTIGATION <br /> 3.1 Geology and Hydrogeology <br /> Soils observed during the drilling of MW-4, MW-5 and MW-6 consisted of massive intervals of <br /> clay, silt and fine sand mixtures to the total drilling depth of approximately 55 feet Detailed soil <br /> descriptions are included on the monitoring well logs (Appendix C) <br /> During the drilling of MW-4, MW-5 and MW-6 on December 1 and 2, 2003, saturated soil and <br /> groundwater were first encountered under water table conditions at approximately 50 feet bgs <br /> Groundwater recharge was observed to be moderately strong <br /> On December 19, 2003, the depth to static groundwater across the site ranged from 48 17 feet <br /> bgs in MW-6 to 50 34 feet bgs to MW-1 The corresponding groundwater surface elevation <br /> ranged from a high of 29 45 feet below mean sea level (msl) at MW-6 to a low of 31 13 feet below <br /> msl at MW-1 The resulting groundwater surface appears as an irregular plane dipping toward the <br /> east-southeast at a gradient of approximately 0 0020 foot/foot The groundwater elevation at <br /> MW-1 does not appear to fit the regional trend, possibly due to the presence of free product A <br /> groundwater surface contour map is included as Figure 4 The well construction details, wellhead <br /> elevations and groundwater monitoring data are summarized in Table 2 <br /> 3.2 Soil and Groundwater Analytical Results <br /> All three soil samples collected from the boring for MW-6 contained detectable concentrations of <br /> gasoline compounds The maximum concentrations detected at MW-6 included 1 7 mg/kg of <br /> TPH-as-gasoline, 0 43 mg/kg of benzene, 0 014 mg/kg of ethylbenzene, and 0 059 mg/kg of <br /> xylenes Oxygenate compounds and 1,2-DCA were not detected in any of the soil samples <br /> analyzed, and no gasoline compounds were detected in the sod samples collected from MW-4 <br /> and MW-5 These soil sample results are summarized in Table 1, and the laboratory reports are <br /> included in Appendix D <br />' The groundwater samples collected from MW-2, MW-4 and MW-6 contained detectable <br /> concentrations of gasoline compounds These groundwater sample results are summarized in <br /> Table 3, the distribution of TPH-as-gasoline, benzene, and MTBE in groundwater is shown on <br /> separate isoconcentration maps (Figures 5, 6, and 7), and the laboratory reports are also included <br /> in Appendix D <br /> 11 <br /> 1 <br />