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31 April 2006 <br /> AGE-NC Project No 97-0326 <br />' Page 3 of 6 <br />' 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> At the time of the March 2006 sampling event, depths to ground water ranged from 33 49 feet to <br /> 35 97 feet below the tops of the well casings First-encountered ground water was within the <br /> screened interval of wells MW-2 and MW-3,MW-7,MW-8A,and MW-9A,these wells should yield <br /> samples representative of shallow ground water conditions Ground water was 0 33 ft above the <br /> screen interval in MW-1, due to "flooding", MW-I may not be representative of shallow ground <br /> water conditions Ground water from deep-screened wells MW-8B-D and MW-9B-D should yield <br /> samples representative of deeper ground water conditions (Table 1) <br /> 1 The elevation of ground water in each well was calculated by subtracting the depths to ground water <br /> from the casing elevations Ground water elevations ranged from 20 05 feet(MW-9A)to 20 82 feet <br /> I (MW-8D) below mean sea level (MSL) <br /> A ground water elevation map of first-encountered ground water is presented in Figure 3 <br /> I First-encountered ground water was inferred to be flowing toward the south under a hydraulic <br /> gradient of approximately 0 003 foot/foot (ft/ft) The flow direction is generally consistent with <br /> previous monitoring events <br /> 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> 1 <br /> Twelve ground water samples were collected and submitted for laboratory analysis for the <br />' constituents listed in Section 2 2 (Table 2) The analytical results for each hydrogeologic unit are <br /> characterized below <br /> HUI - TPH-g was detected in ground water samples collected in HUI from wells MW-1, MW-2, <br /> MW-3, MW-8A, and MW-9A at concentrations ranging from 2,000 micrograms per liter(gg/l) in <br /> sample MW-8A to 110,000 µg/1 in sample MW-3 (Figure 4) <br /> BTEX compounds were detected in ground water samples collected in HUI from wells MW-1, <br /> MW-2, MW-3, MW-8A, and MW-9A at maximum concentrations of 24,000 µg/1 benzene, <br /> 14,000 pg/l toluene, 6,200 µg/l ethylbenzene, and 33,000 gg/l xylenes in sample MW-3 <br /> The fuel additives MTBE, TAME, and 1,2-DCA were detected in ground water samples collected <br /> in HUI from wells MW-1, MW-2, MW-3, MW-8A, and MW-9A at maximum concentrations of <br /> 1,700 µg11 MTBE(MW-9A), 240 µg/l TAME (MW-2 and MW-3), and 150 µg11 1,2-DCA(MW-2 <br /> and MW-3), DIPE was detected in sample MW-1 at a concentration of 9 7 µg11 The areal <br />' distribution of MTBE within HUI is depicted on Figure 5 <br /> • <br /> Advanced GeoEnvironmental,Inc <br /> 1 <br />