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1 02 February 2004 AGE-NC Project No 99-0624 ' Page 6 of 8 s ' 3 3 GROUND WATER GRADIENT AND FLOW DIRECTION At the time of the September 2003 sampling event, depths to ground water ranged from 54 56 feet ' to 55 63 feet below the tops of the well casings Ground water elevations at the site ranged from 16 13 feet below mean sea level (MSL) in well MW-4 to 16 40 feet below MSL in well MW-6 (Table 2) During this monitoring event,the ground water levels in wells MW-1 through MW-4 and ' MW-6 were at least nine feet below the tops of the well screens, indicating that the wells are screened properly to yield representative shallow ground water samples The ground water elevation at the site decreased approximately 2 45 feet between the June 2003 and September 2003 monitoring ' events Ground water on 22 September 2003, was inferred to be flowing toward the south in the western ' portion of the site and towards the south-southeast in the eastern portion of the site The average ground water gradient was determined to be 0 002 feet/feet Figure 7 illustrates the contoured ground water elevations as measured on 22 September 2003 I . 34 ANALYTICAL RESULTS OF GROUND WATER SAMPLES - 24 JULY 2003 TPH-g was detected in the water sample collected from well MW-7 at a concentration of ' 87 micrograms per liter(µg/1) Benzene,ethylbenzene and xylenes were detected in the same sample at concentrations of 0 84 µg/1, 0 63µg11 and 1 3 µg/1, respectively Utilizing EPA Method 8260, the fuel additives MTBE was detected in the ground water samples collected from wells MW-6 and MW-7 at concentrations of 1 1 µg/1 and 160 µg/1,respectively, and TAME was detected in sample MW-7 at a concentration of 1 3, µg/1 Analytical results are summarized in Table 5 The laboratory report (CAL Reference No 5922) and chain-of-custody forms are presented in Appendix F 3 5 'ANALYTICAL RESULTS OF GROUND WATER SAMPLES - 22 SEPTEMBER 2003 ' TPH-g was detected in the water sample collected from wells MW-1 and MW-2 at concentrations of 51 µg11 and 2,800 gg/l,respectively Benzene,ethylbenzene and xylenes were detected only in the sample collected from MW-2 at concentrations of 11 µg/1 10 µg/1 and 23 µg/1; respectively Utilizing EPA Method 8260, the fuel additives MTBE was detected in samples MW-1, MW-2, MW-3 and MW-7 at concentrations ranging between 16 µg/l (MW-7) and 7,500 µg/1 (MW-2), and TAME and ETBE were detected in sample MW-2 at concentrations of 51 µg/1 and 3 6 µg/1, respectively No other constituents of concern were detected above laboratory reporting limits in the Advanced GenEnvironmental,Inc I