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r r05 March 2002 AGE-NC Project No 98-0465 Page 3 of 4 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES Each sample was analyzed for TPH-g, TPH-d, BTEX, and for the suite of five oxygenated fuel r additives TPH-g, TPH-d and BTEX were not detected at concentrations at or above the laboratory reporting limits In any of the ground water samples MTBE was detected by EPA Method 802.0 In the ground water samples collected from MW1 and MW3 at concentrations of 7 7 µg/1 and 73 µg11, respectively MTBE was detected In samples collected from MW1, MW3 and MW4 by EPA Method 8260 at concentrations of 8 7 gg/l, 93 µg11 ' and 4 4 gg/l, respectively No other fuel oxygenated compounds were detected in the ground water analyses Figure 4 Illustrates the approximate extent of MTBE-Impacted ground water ' Analytical results of water samples collected during January 2002 are summarized on Table 2, the laboratory report (MAI Lab No 88292 through 88295), QA/QC report and chain-of-custody form ' are included In Appendix B 4.0. SUMMARY AND CONCLUSIONS The following conclusions were drawn from the results of this Investigation C The ground water elevations ranged from 6 19 to 6 42 feet below MSL Ground water was flowing radially toward the north, varying from northwest to northeast, under an average ' gradient of 0 002 feet/feet The ground water elevation at the site increased an average 3 32 feet between the October 2001 and January 2002 monitoring events C MTBE was detected in samples collected from MW-1,MW-3 and MW-4 at concentrations ' of 8 7 µg/l, 93 µg/1 and 4 4 µg/1, respectively, by EPA Method 8260 C Concentrations of dissolved MTBE In samples collected from MW-1 and MW-3 have rremained relatively stable since ground water monitoring began In July 2000 G The lateral extent of MTBE-Impacted ground water has been defined to the northeast of the former UST area, but not toward the west to northwest, east or south ' 5.0. RECOMMENDATIONS ' Based on the findings of this Investigation,AGE recommends continued quarterly monitoring of the ground water monitoring wells The next monitoring event should be performed In March 2002 rAdvanced GeoEnvironmental,Inc r