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I19 July 2002 • AGE-NC Project No 95-0173 ' Page 4 of 8 ' 4.0. FINDINGS Ground water elevation, flow direction and gradient were determined from field data collected on I 08 March 2002, the contaminant impact to ground water was quantified from the ground water laboratory data ' From field and laboratory data collected at the SVE remediation system between 31 December 2001 and 29 March 2002, AGE determined the average TPH-g concentration, the average flow rate and calculated the approximate mass and volume of hydrocarbons removed 4 1 GROUND WATER ELEVATION AND GRADIENT ' During the March 2002 ground water monitoring event, depths to ground water in the monitoring wells were measured between 25 41 and 27 84 feet below the tops of well casings, ground water ' elevations were calculated to be between 16 79 feet(MW-8) and 17 76 feet(MW-5)below mean sea level Ground water elevation at the site increased an average 1 31 feet between the December 2001 • and the March 2002 ground water monitoring events Nine of the wells were "drowned", the Iscreened-interval was approximately 3 feet below the water table in wells MW-1 through MW-4, between 10 and 30 feet below water in wells AW-1A through AW-2B and approximately 70 feet ' below water in well MW-13 The ground water elevation data for the March 2002 ground water monitoring event is depicted in I Figure 3 Ground water flow direction at the site was inferred to be toward the northeast at a gradient of 0 002 ft/ft or less, or approximately 11 feet per mile (Figure 3) 4 2 LABORATORY RESULTS OF GROUND WATER SAMPLES A total of seventeen ground water samples were submitted to Castle Analytical Laboratory(CAL), a DHS-certified laboratory, for analysis TPH-g was detected in ground water samples collected from wells MW-1 through MW-4, MW-6, MW-9, MW-13, and AW-1A through AW-2B, at concentrations as high as 190,000 micrograms per liter(yg/1) in the sample from AW-2A BTEX compounds were detected in ground water samples collected from wells MW-1 through ' MW-4, MW-6, MW-13, and AW-lA through AW-2B at concentrations as high as 45,000 µg/1 (toluene, AW-2A) The maximum benzene concentration was detected from sample AW-2A at a concentration of 14,000µg/1 Advanced GeoEnvironmental,Inc