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' 10 May 2002 . AGE-NC Project No 96-0229 ' Page 3 of 5 ' The general ground water gradient In the area of wells MW-1 through MW-10 was calculated to be approximately 0 001 f1/ft or less, or approximately 5 feet per mile and inferred to be flowing towards the northeast The ground water surface elevation at the site is approximately 17 and 19 feet above the slotted screen Intervals in wells MW-1 and MW-10B, respectively, but within the screened Intervals of the screened Intervals of the remaining wells 3 2 LABORATORY RESULTS OF GROUND WATER SAMPLES ' A total of eleven ground water samples were submitted to a DHS-certified laboratory TPH-g was detected in water samples collected from wells MW-1, MW-2, MW-3, MW-6, MW-7, MW-9 and MW-l0A at concentrations ranging as high as 73,000 micrograms per liter (,ug/1) in well MW-6 ' BTEX constituents were detected In ground water samples collected from wells MW-1, MW-2, MW-3, MW-6 and MW-9 at concentrations ranging as high as 15,000 µgll (xylenc, MW-6) The fhighest benzene concentration was detected in sample MW-1 at a concentration of 8,600 µg11 • MTBE was detected (EPA 8260) in ground water samples collected from wells MW-1, MW-2, MW-3, MW-6, MW-7, MW-8, MW-9, MW-l0A and MW-IOB at concentrations ranging as high as 2,400 ,ug/1 (MW-6) DIPE was detected in a water sample collected from MW-1 at a concentration of 13 µg/1, TAME was detected In water samples collected from MW-7 and MW-10A at concentrations of 6 8 µg/1 and 1 3 4g/1, 1,2-DCA was detected in samples collected from MW-1, MW-2, MW-7, MW-8, MW-9, MW-10A and MW-10B at concentrations as high as 210 µg/l No other constituents of concern were detected above laboratory reporting limits in the analyzed samples Previous and current analytical results of ground water monitoring well samples are summarized In Tables 3 and 4 The laboratory reports (Castle Analytical Laboratories Reference No 4327) and chain-of-custody forms are presented In Appendix B ' 4.0. SUMMARY AND CONCLUSIONS The Implications from the findings of the December 2001 Investigation are • Ground water flow direction in the area of wells MW-1 through MW-10 was Inferred to be towards the northeast at an approximate gradient of 0 001 ft/ft This appears to be the prevailing flow direction for the area e _Due to the low_ hydraulic gradient at_the_site, slight variations In ground water measurements _ or changes of recharge/discharge of the local ground water could greatly modify the in ground water flow direction Advanced GeoEnvironmental,Inc