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1 <br />' 05 November 2002 <br /> AGE-NC Protect No 96-0229 <br />' Page 4of5 <br />' at concentrations of 140 µg/1 and 0 56 µg/1, respectively, D1PE was detected in a water sample <br /> collected from MW-1 at a concentration of 8 pg/l <br />' No other constituents of concern were detected above laboratory reporting limits in the analyzed <br /> samples Previous and current analytical results of ground water monitoring well samples are <br /> summarized in Tables 3 and 4 The laboratory reports (McCampbell Analytical Inc Lab I D No <br />' 0205259 and Castle Analytical Laboratory reference no 4691) and chain-of-custody forms are <br /> presented in Appendix C <br />' 4.0. SUMMARY AND CONCLUSIONS <br />' The implications from the findings of the May 2002 investigation are <br /> • Ground water flow direction in the area of wells MW-1 through MW-10 was inferred to be <br /> towards the northeast at an approximate gradient of 0 002 ft/ft This appears to be the <br /> prevailing flow direction for the area <br />�S • Due to the low hydraulic gradient at the site,slight variations in ground water measurements <br /> or changes of recharge/discharge of the local ground water could greatly modify the inferred <br /> ground water flow direction <br /> • Monitoring wells MW-1 and MW-1OB are"drowned", and yield samples representative of <br /> deeper ground water conditions Deeper ground water in the area of MW-1 (48 to 53 feet <br /> bsg) is impacted by significant TPH-g, BTEX, 1,2-DCA and MTBE, deeper ground water <br /> in the area of downgradient well MW-10B is impacted by minor MTBE <br /> O Significant MTBE concentrations were detected in the sample collected from well MW-1 <br /> (screened 48 to 53 feet bsg) in deeper ground water, however only minor MTBE <br /> concentrations were detected in the samples collected from shallow water on-site wells MW- <br /> 2(located 5 feet from MW-1),implying that a deeper,vertically undelineated MTBE-impact <br /> maybe present crossgradient to downgradient of the site (Figure 5) <br /> • The highest concentrations of off-site dissolved MTBE were detected in downgradient well <br /> MW-6, a trend of increasing off-site MTBE concentrations has generally been noted since <br /> March 2001 <br /> • TPH-g, BTEX and MTBE were reported for the third consecutive quarter in water samples <br /> collected from MW-9, suggesting that the plume of petroleum--impacted ground water may <br /> have shifted towards the east <br /> IAdvanced GcoEnvironmental,Inc <br />