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3 0 RESULTS OF THE INVESTIGATION <br /> 3.1 Geology and Hydrogeology <br /> Sods observed to the total drilling depth of 35 feet below street grade mostly consisted of clay, silt <br /> and fine sand mixtures Intervals of well-sorted sand were not observed Detailed soil <br /> descriptions are included on the monitoring well logs (Appendix E) <br /> During drilling on July 13, 2002, saturated soil was first encountered in the three monitoring well <br /> borings at approximately 19 0 feet below grade (approximately 30 feet below street grade) On <br /> July 24, 2002, the static depth to the groundwater table, as measured in the three completed <br /> groundwater monitoring wells, ranged from 14 35 feet below grade in MW-1 to 26 38 feet below - <br /> street grade in MW-3 <br />' The groundwater surface elevation in the three wells ranged from a high of 14 21 feet below mean <br /> sea level (msl) at MW-1 to a low of 14 82 feet below msl at MW-3 The resulting groundwater <br /> surface appears as a regular plane dipping to the northeast at a gradient of approximately 0 0076 <br /> foot/foot A groundwater surface contour map is included as Figure 4 The well construction <br /> details, wellhead elevations and groundwater monitoring data are summarized in Table 3 <br /> 32 Analytical Results <br /> Only 2 of the 9 soil samples collected during the drilling contained detectable concentrations of <br /> P 9 g <br /> gasoline hydrocarbons The soil sample collected at 15 feet from MW-1 contained 1,800 <br /> milligrams per kilogram (mg/kg) of TPH-as-gasoline, 2 2 mg/kg of benzene, 43 mg/kg of toluene, <br /> 31 mg/kg of ethylbenzene, and 150 mg/kg of xylenes The sod sample collected at 20 feet from <br />' MW-1 only contained 0 026 mg/kg of ethylbenzene and 0 012 mg/kg of xylenes The five <br /> oxygenates and 1,2-DCA were not detected in any of the soil samples The soil sample analytical <br />' results are summarized in Table 1, the concentrations of gasoline compounds in soil are shown in <br /> cross-section (Figure 5), and the laboratory reports are included in Appendix F <br /> Only the groundwater sample collected from MW-1 contained detectable concentrations of <br /> gasoline hydrocarbons This sample contained 27,000 micrograms per liter (Pg/1) of TPH-as- <br />' gasoline, 1,800 µg/I of benzene, 4,300 µg11 of toluene, 1,600 µg11 of ethylbenzene, 5,200 µg/I of <br /> xylenes, and 45 µg11 of MTBE The groundwater sample analytical results are summarized in <br /> Table 2, the distribution of gasoline in groundwater is shown on Figure 6, and the laboratory <br /> reports are included in Appendix F <br /> 12 <br /> 1 <br />