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3.0 PROJECT RESULTS <br /> 31 Geology and Hydrogeology <br /> Consistent with previous investigations, the uppermost 30 feet of soil at well borings MW-7, MW- <br /> 8, and MW-9 consists of a massive sandy soil sequence interbedded with intervals of clay, silt and <br /> fine sand mixtures The descriptions of soil observed during the drilling of MW-7, MW-8, and <br /> MW-9 are included on the monitoring well logs (Appendix C) <br /> Based on previous CPT borings, the soil between 30 and 150 feet consists of a massive <br /> sequence of clay and silt sods interrupted by several discontinuous intervals of sand and gravel <br /> sods The distribution of the sand and gravel intervals is interpreted in cross-section (Figure 4) <br /> During the drilling of MW-7, MW-8, and MW-9, groundwater was first encountered at a depth of <br /> between 19 and 21 feet bgs On April 25, 2005, the static depth to the groundwater table, as <br /> measured in the nine monitoring wells, ranged from 18 73 feet bgs in MW-6 to 20 62 feet bgs in <br /> MW4 The corresponding groundwater surface elevations ranged from a high of 18 00 feet <br /> above mean sea level (msl) at MW-1 to a low of 17 04 feet above msl at MW-7 The resulting <br /> groundwater surface appears as an irregular plane dipping to the north-northeast at a gradient of <br /> approximately 0 0071 foot/foot A groundwater surface contour map is included as Figure 5 The <br /> well construction details and groundwater monitoring data are summarized in Table 8 <br /> 32 Analytical Results <br /> The sal samples collected at 15, 20 and 25 feet from well borings MW-7, MW-8, and MW-9 did <br /> not contain detectable concentrations of gasoline compounds These soil sample analytical <br /> results are summarized in Table 5, and the laboratory report is included in Appendix E <br /> From the nine monitoring wells, only the groundwater sample collected from MW-2 contained <br /> detectable concentrations of gasoline compounds 0 6 µg/I of ethylbenzene, 1 3 µg11 of xylenes, <br /> and 1 4 µg/l of MTBE The distribution of gasoline compounds (TPH-as-gasoline, benzene, and <br /> MTBE) at the groundwater table is shown on Figure 6 The groundwater sample analytical results <br /> are summarized in Table 7, and the laboratory reports are included in Appendix E <br /> 12 <br />