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' 15 September 2005 AGE-NC Project No 96-0229 ' Page 5 of 6 ' • Generally,depth to ground water at the site varied between 30 feet and 32 feet below the tops of the well casings, ground water elevations ranged between 16 99 feet(MW-5) and 18 97 feet(MW-19C) below mean sea level (Table 2) ' • First Zone ground water flow direction at the site Inferred a net ground water flow towards the northeast at a hydraulic gradient of approximately 0 003 ft/ft (Figure 4) ' • Second Zone ground water flow direction at the site Inferred a net ground water flow direction towards the east at hydraulic gradients of approximately 0 006 ft/ft(Figure 5) • The most Intense TPH-g-impacted ground water was reported in the area of First Water Zone ' wells MW-2 and MW-6 at concentrations as high as 27,000 pg/l, the First Water Zone TPH-g plume appears to have migrated at least 300 feet towards the northeast ' (downgradient)in the area of well MW-9(Figure 6) TPH-g was not detected this quarter in the samples collected from wells MW-10 and MW-19 • The most intense MTBE-impacted ground water was reported in the area of First Water Zone well MW-6 (screened 25-45 ft) at a concentration of 85 µg/l, the First Water Zone MTBE plume appears to have migrated at least 400 feet towards the east and northeast . (downgradient) beyond the areas of wells MW-9 and MW-16A and 300 feet towards the northwest at well MW-11 (Figure 7) MTBE concentrations decreased to non detect this quarter in samples from wells MW-3 and MW-10A In addition dissolved MTBE concentrations declined significantly in wells MW-1, MW-2 and MW-3 on the site and off-site m wells MW-9 and MW-10B,and increased slightly in wells MW-4,MW-6,MW-11 and MW-19A • Significant concentrations of 1,2-DCA were detected in the samples collected from wells MW-1,MW-2 and MW-3 and down-gradient at wells MW-6,MW-9, MW-10B, MW-16C, MW-17A, MW-18 (B-C) and MW-19A (Figure 8) Detections indicate that 1,2-DCA may have laterally migrated 400 feet towards the northeast to the area of MW-18(B-C)(screened 50-55 feet and 62-67 feet), however, the vertical extent appears to be defined on-site by the adjacent multi-level well MW-13 (A-D)and off-site to the northeast by multi-level well MW-17 (B-C) 5.0. RECOMMENDATIONS Based upon data collected during April 2005, AGE recommends • Continued utilization of wells MW-1 through MW-19 for quarterly groundwater monitoring and sampling,The third quarter 2005 ground water monitoring event is tentatively scheduled • for September 2005 Advanced GeoEnvironmental,Inc