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' 03 February 2003 AGE-NC Project No 9 8-046 5 ' Page 3 of 4 ' 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES 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 in samples collected from MW1, MW3 and MW4 by EPA Method 8260B at ' concentrations of 690 pg/l, 12 µg11 and 0 82 µg11,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 November 2002 are summarized on Table 2, the laboratory report(MAI Lab IDs 0211391-001 through 0211391-004),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 ' 0 The ground water elevations ranged from 9 53 to 9 65 feet below MSL Ground water was inferred to flow radially toward the northeast,varying from northwest to northeast,under an ' average gradient of 0 001 feet/feet G TPH-g, TPH-d and BTEX were not detected in the ground water samples collected and ' analyzed during the fourth quarter 2002 C MTBE was detected in samples collected from MW-1,MW-3 and MW-4 at concentrations of 690 gg/l, 12 µg11 and 0 82 gg/l, respectively, by EPA Method 8260B The sample ' collected from MW-1 during the November 2002 monitoring event contained the highest detected concentration of dissolved MTBE since monitoring began in July 2000 However, the detected concentrations of MTBE in MW-3 and MW-4 have remained relatively stable during the same period c 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 ' Advanced GeoEnvironmentil,Inc