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I ' 25 February 2005 AGE-NC Project No 96-0229 ' Page 5 of 6 ' • Generally,depth to ground water at the site varied between 33 feet and 37 feet below the tops of the well casings, ground water elevations ranged between 20 90 feet (MW-4) and 23 66 (MW-12) feet 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 0 005 ft/ft(Figure 4), off-site towards the north and northeast(wells MW-6 through MW-12),net ground water flow was oriented ' more towards the north-northeast at hydraulic gradients of 0 005 ft/ft • Second Zone ground water flow direction at the site inferred a net ground water flow ' direction towards the east at hydraulic gradients between 0 007 ft/ft and 0 008 ft/ft(Figure 5) • Due to the low hydraulic gradient at the site, slight variations in ground water ' recharge/discharge could greatly modify the inferred ground water flow direction • 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 53,000 µg/l (Figure 6) • The highest concentrations of dissolved MTBE were detected off-site from First Water Zone wells MW-6(screened 25-45 feet)and MW-9(screened 20-40 ft),and from First Confining Unit well MW-1 (screened 48-53 feet) Lesser MTBE concentrations were detected onsite from First Water Zone wells MW-2 and MW-4 and off-site from wells MW-16 (B and C) and MW-19A The vertical extent of MTBE appears to be approximately between 45 feet ' (MW-6) and 62 feet (MW-19A/MW-16C) • TPH-g, BTEX, and MTBE were reported for the 12" consecutive quarter in water samples I collected from MW-9, a significant decrease in TPH-g, BTEX, and MTBE concentrations was evident between the November 2003 and the June 2004 monitoring events, however significant increase in TPH-g, BTEX, and MTBE concentrations was evident between. the June 2004 and September 2004 monitoring events (Table 3) • Significant concentrations of 1,2-DCA were detected in the samples collected from wells MW-1 and MW-2,however,the vertical extent appears to be defined by the adjacent multi- level well MW-13 1 • 5.0. RMOMMENDA HON S IBased upon data collected during June 2004, AGE recommends • Continued utilization of wells MW-1 through MW-19 for quarterly groundwater monitoring and sampling,the fourth quarter 2004 ground water morutori ng event was performed on 07- 08 December 2004 and a report of findings is pending The first quarter 2005 ground water Advanced GeoEnvironmental,Tne I