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30 July 2003 <br /> AGE-NC Project No 01-0865 <br /> Page 3 of 6 <br /> 3.0 FINDINGS <br /> Ground water elevation, flow direction, and gradient were determined from field data collected on <br /> 11 June 2003,the contaminant impact to ground water was quantified from the laboratory analytical <br /> data obtained from the sampling event <br /> 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> The elevation of ground water m each well was calculated by subtracting the depth to ground water <br /> from the surveyed well casing elevation(Table 1) The depth to ground water ranged from 2 67 feet <br /> (MW-7)to 7 09 feet(MW-2)below the tops of the well casings Ground water elevations at the site <br /> ranged from 14 61 feet below MSL in well MW-4 to 18 53 feet below MSL in well MW-10 The <br /> ground water elevations at the site decreased an average of approximately 121 feet between the <br /> March 2002 and June 2003 sampling events Ground water was within the screened interval of all <br /> the shallow-screened monitoring wells <br /> . The ground water flow direction of first ground water on 11 June 2003 was inferred to be towards <br /> the southeast under an average ground water gradient of 0 040 feet/feet(Figure 3) <br /> The ground water flow inferred from deep-screened (50 feet to 60 feet bsg) wells MW-6 through <br /> MW-8 was northeast, but under a much shallower average gradient of 0 002 feet/feet (Figure 4) <br /> 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-g was detected in the water samples collected from wells MW-2 through MW-6 and EW-1 at <br /> concentrations ranging from of 1,200 micrograms per liter(µg/1)in MW-5 to 80,000 µg/1 in MW-2 <br /> An iso-concentration map illustrating the approximate distribution of dissolved TPH-g is depicted <br /> on Figure 5 <br /> One or more BTEX compounds were detected in.the samples collected from wells MW-3, MW-4 <br /> MW-6 and EW-1 at the following maximum concentrations 49 µg/1 benzene (MW-6), 200 µg/1 <br /> toluene (MW-3), 6 6 µg/1 ethylbenzene (MW-6) and 522 7 µg/1 xylenes (MW-4) An iso- <br /> concentration map showing the approximate distribution of dissolved benzene is provided in <br /> Figure 7 <br /> MTBE was detected in the samples collected from every well except wells MW-7, MW-8 and <br /> MW-10 at concentrations ranging from 36 µg11 in MW-4 to 71,000 µg/1 in MW-2 <br /> Advanced GeuEnvaronmental,Inc <br />