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1 <br />' 05 November 2002 <br /> AGE-NC Project No 96-0229 <br />' Page 3 of 5 <br />' 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> Dunng the 14 May 2002 monitoring event,depths to ground water in wells MW-1 through MW-l OB <br /> were measured between 28 31 and 30 16 feet below the tops of the well casings (Table 2) Ground <br /> water elevations were calculated to be between 17 74 feet(MW-5)and 19 21 feet(MW-10B)below <br /> mean sea level (MSL), the ground water elevation increased an average of 0 24 feet between the <br />' February 2002 and the May 2002 ground water monitoring events The ground water surface <br /> elevation at the site was within the screened intervals of wells MW-2, MW-3, and MW-5 through <br /> MW-10A, but was approximately 17, 1 5 and 19 feet above the screen intervals in wells MW-1, <br />' MW-4 and MW-IOB, respectively <br /> The ground water elevation data for MW-2 through MW-10A during the May 2002 ground water <br />' monitoring event is depicted and contoured in Figure 3, elevation data for deep-screened wells <br /> MW-1 and MW-10B were not used to determine ground water gradient because these elevations may <br /> be representative of deeper ground water conditions <br />' The general ground water gradient in the area of wells MW-1 through MW-10 was calculated to be <br />'• approximately 0 002 ft/ft or less, or approximately 11 feet per mile, and inferred to be flowing <br /> towards the northeast <br /> 3 2 LABORATORY RESULTS OF GROUND WATER SAMPLES <br /> A total of eleven ground water samples were submitted to Castle Analytical Laboratory, a DHS- <br /> certified laboratory in Atwater, California <br /> TPH-g was detected in water samples collected from wells MW-1, MW-2, MW-3, MW-6, MW-7, <br /> MW-9 and MW-10A at concentrations between 260 micrograms per liter(pg/1) in well MW-9 and <br /> 100,000µg/1 in wells MW-2 and MW-6 <br /> BTEX constituents were detected in ground water samples collected from wells MW-1, MW-2, <br /> MW-3, MW-6, MW-7, MW-9 and MW-I OA at a maximum concentration of 20,000 µg/1 (xylene, <br /> MW-6),the highest benzene concentration was detected in sample MW-1 at a concentration of 6,700 <br /> µg/1 <br /> MTBE was detected by EPA Method 8260 in ground water samples collected from wells MW-1, <br /> MW-2, MW-3, and MW-6 through MW-IOA at a maximum concentration of 1,800 µg/1 (MW-6), <br /> TBA was detected in samples collected from wells MW-4 and MW-9 at concentrations of 5 2 µg/1 <br /> and 5 1 µg/l,respectively, 1,2-DCA was detected in samples collected from wells MW-1 and MW-9 <br /> Advanced GeoEnvironmental,Inc <br /> I <br />