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29 March 2002 iAGE-NC Project No 96-0254 Page 3 of 5 3 1 GROUND WATER ELEVATION AND GRADIENT The elevation of ground water in each well was calculated by subtracting the depth to ground water from the surveyed well casing elevations (Table 1) The depths to ground water in wells MW-1 through MW-7 and GLMW-3 were measured between 6 70 feet and 8 47 feet below the tops of the well casings Ground water elevations at the site ranged from 28 81 feet above mean sea level(MSL)in well MW-7 to 30 53 feet above MSL in well MW-6 Ground water elevations at the site increased an average 0 24 feet between the October 2001 and IJanuary 2002 sampling events The ground water flow direction for the 23 January 2002 sampling event was inferred to be toward I the north at an average hydraulic gradient of 0 006 feet/feet Data from MW-1 A,MW-2A and MW-7 was not used to determine ground water gradient Wells MW-IA,MW-2A and MW-7 are screened at a deeper interval than the other wells Figure 3 illustrates the contoured ground water elevations I 3 2 MICROBIOLOGICAL ACTIVITY IN GROUND WATER The general counts of heterotrophic organisms were 11 7 X 105 cfu/g and the selective counts were 3 4 X 105 cfu/g in the water sample collected from MW-1B Nitrates (NOA nitrites (NO2) and ammonium (NH4) were detected in the sample from MW-113 at concentrations of 30 8 parts per million (ppm), 32 8 ppm and 23 22 ppm, respectively Additional nitrogen and phosphorous Inutrients were detected in the water sample Concentrations are summarized on Table 3 The laboratory results indicate the presence of moderate populations of organisms capable of gasoline metabolism However, nutrient concentrations are at moderate to high levels for ongoing bioremediation Microbiological and physicochemical analytical results are summarized on Table 4 The laboratory report and chain-of-custody form are included in Appendix B 33 LABORATORY RESULTS OF GROUND WATER SAMPLES ITPH-g was detected in the samples collected from wells MW-1B and MW-4 at concentrations of 3,400 micrograms per liter(}tg/l)and 1,400µg/1 TPH-d was detected in the water samples collected from wells MW-4 and MW-7 at concentrations of 110 µg/1 and 62 µg/l TPH-g and TPH-d were not detected in the remaining samples IBTEX compounds were detected in the ground water samples collected from monitoring wells • MW-1B and MW-4 at concentrations as high as 920 µg/1 benzene, 58 µg/l toluene, 83 µg/l ethylbenzene and 59 µg/l xylenes Advanced GeoEnvironmenta]Inc