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L I A e ' 29 March 2001 AGE-NC Project No 98-0448 ' Page 3 of 5 ' between 17 70 and 20 02 feet below the tops of the well casings Ground water elevations at the site were calculated to be between 8 97 feet and 10 61 feet below mean sea level, ground water elevations are depicted in Figure 3 Ground water elevation at the site decreased an average 1 14 feet 'r between the August 1999 and January 2001 ground water monitoring events The general ground water gradient at the site was calculated to be approximately 0 009 ft/ft, or ' approximately 47 feet per mile, directed towards the south-southwest (Figure 3) ' 3 2 LABORATORY RESULTS OF GROUND WATER SAMPLES TPH-g was detected in water samples collected from wells MW-1, MW-4A, MW-4B and MW-6 at ' concentrations ranging from 110 micrograms per liter(,ugll) to 66,000,ug/l The inferred extent of dissolved TPH-g is depicted in plan view in Figure 4 ' Various BTEX compounds were detected in water samples collected from MW-1,MW-4A,MW-4B and MW-6 at concentrations as high as 9,400µg/l, the greatest benzene concentration was detected in the sample collected from MW-4B at a concentration of 5,000µg/l MTBE was detected in a water sample collected from MW-4B at a concentration of 33 1 P 1-�t� , DIPE was detected in a water sample collected from MW-1 at a concentration of 3 3 ,ug/l No other fuel oxygenated compounds were detected by laboratory analysis Previous and current analytical results of ground water monitoring well samples are summarized in Tables 2 and 3 The laboratory reports (McCampbell Analytical Inc I D 58607 through 58611) and chain-of-custody forms are presented in Appendix B 4.0. DISCUSSION AND CONCLUSIONS, The implications from the January 2001 ground water monitoring event are as follows Ground water-flow direction at the site appeared to be oriented generally towards the south- - ' southwest at a gradient of 0 009, due to the low gradient at the site, slight variations in ground water measurements or changes of recharge/discharge of the,local ground water could greatly modify ground water flow direction • The ground water elevation at the site was within the screened intervals of wells MW-1, MW-2, MW-3, MW-4A,MW-5, MW-6, MW-7 and MW-8 and is representative of shallow ground water conditions, however well MW-4B is"drowned"with water approximately 25 . feet over the screen and yields a sample more representative of deeper ground water Advanced CeoEnvnronmental,Inc i