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n _ v Y 11 December 2000 r' AGE-NC Project No 97-0312 Page 3 of'4 ' ' 3 1 GROUND WATER ELEVATION AND GRADIENT r Ground water elevation decreased an average of 4 93 feet at the site since the 14,June 2000 momtonng event Ground water flow direction was inferred to be northeasterly at a low gradient of 0 0007 ft/ft The flow direction has rotated approximately 90 degrees clockwise to that of the " previous momtonng event Figure 4 depicts the groundwater elevation contours for September 2000 Static ground water was'within the screened interval in UST-5, 2 feet above the screened interval of UST-6, 5 feet above the screened interval ofUST-2, UST-3 and UST-4, and approximately 24 feet above the screened interval in UST-1 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g, benzene and toluene were detected in the water sample collected from UST-5 at ' concentrations of 580 micrograms per liter (µg/1), 23 µg/1 and 2 3 µg/1, respectively TPH-d was detected in the samples collected from UST-1, UST-4, and UST-5 at concentrations as high as 460 µg/1 from UST-1 Petroleum hydrocarbons were not detected in wells UST-2, UST-3 and UST-6 Petroleum hydrocarbons were not detected in the two on-site domestic wells on either 20 or 28 September 2000 MTBE and fuel oxygenated compounds were not detected above laboratory reporting levels in the ground water samples collected this quarter 1,2-Dichloroethane (1,2!-DCA) was detected in the ' samples collected from UST-5 and UST-6 at concentrations of 750 µg/1 and 4 0 µg/l, respectively The laboratory report (MAI sample Nos 49051- 49058 and 48130-48131) and chain-of-custody forms are included in Appendix B Analytical results of water samples collected in September 2000 ' are summarized on Table 2 The analytical results of all water samples are summarized on Table 3 Chlorinated hydrocarbons were not detected in either of the domestic well samples or in any of the 'i monitoring well samples 4.0. DISCUSSION AND CONCLUSIONS Based upon data collected from,the site, AGE concludes the following • Grourid water elevation decreased approximately 4 93 feet at,the site between the June and September 2000 monitoring events The inferred ground water flow direction rotated ' approximately 90 degrees clockwise from a northwesterly direction to the more common northeasterly direction'for the area The low grpund water gradient was 0 0007 fllft across Advanced GeoEnvironmental,Inc- ,