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i 30 August 2005 i AGE-NC Project No 96-0229 Page 5 of 6 4.0. SUMMARY AND CONCLUSIONS The Implications from the findings of the April 2005 ground water monitoring event are • Generally,depth to ground water at the site varied between 31 feet and 33 feet below the tops of the well casings,ground water elevations ranged between 18 14 feet(MW-13D)and 20 60 feet(MW-12) 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 0 004 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 0 005 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 200,000 µg/l, the First Water Zone TPH-g plume appears to have migrated at least 425 feet towards the northeast (downgradient) In the areas of wells MW-19110A and MW-9 (Figure 6) • The most intense MTBE-Impacted ground water was reported in the area of First Water Zone well MW-3 (screened 20-40 ft) at a concentration of 680 µg11,the First Water Zone MTBE plume appears to have migrated at least 490 feet towards the northeast (downgradient) beyond the areas of wells MW-10 and MW-18 (Figure 7) MTBE concentrations decreased to non detect this quarter in samples from wells MW-4, MW-11 and MW-19A In addition dissolved MTBE concentrations declined significantly in wells MW-1 and MW-2 on the site and off-site in well MW-9, and Increased substantially In well MW-3 at the east edge of the site (the down-gradient boundary-edge of the site) • Significant concentrations of 1,2-DCA were detected in the samples collected from wells MW-1 and MW-2 and downgradient at wells MW-9, MW-16B and MW-17A, Indicating 1,2-DCA may have laterally migrated 315 feet towards the northeast to the area of MW-17A (screened 62-67 feet), however, the vertical extent appears to be defined onsite 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 SBased upon data collected during April 2005, AGE recommends O Continued utilization ofwells MW-1 through MW-19 for quarterly groundwater monitoring • and sampling,the second quarter 2005 ground water monitoring event was performed on 21 ' Advanced GeoEnvironmenlal,Inc I