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' 15 February 2002 • AGE-NC Project No 99-0559 ' Page 6 of 7 ' ranged from 7 9 µg11 in sample MW-71) to 150 µg/1 in sample MW-51) The other fuel oxygenates were not detected in the hydrologic unit samples Hydrologic unit 6 TPH-g was detected in the ground water sample collected from unit 6 at a concentration of 140 µg/l in sample MW-7E, the only sample containing TPH-g Benzene was detected in sample MW-6E from unit 6, at a concentration of 9 5 µg/1 The remaining BTEX compounds were detected in the two samples collected from unit 6 at concentrations of 0 54 µg/1 toluene in sample MW-5E and 26 µg11 toluene in sample MW-7E MTBE was detected only in one unit 6 sample (MW-5E), utilizing EPA Method 8020, at a concentration of 7 2 µg/1 and has been confirmed by EPA Method 8260, at a concentration of 4 7 µg/l Other fuel oxygenates were not detected in the hydrologic unit samples The analytical results of water samples and hydrologic units are summanzed in Table 2 The laboratory reports (MAI laboratory I D nos 82762-82784 ), quality assurance and quality control (QA/QC) reports and chain-of-custody forms are included in Appendix B iso-concentration maps displaying the estimated distribution of dissolved TPH-g,benzene and MTBE in the hydrologic units are depicted in Figures 8 through 12 4.0. SUMMARY AND CONCLUSIONS Based on data collected during the monitoring event, AGE concludes • The ground water flow direction was determined for each hydrologic unit The upper two units, 112 and 4, flow toward the northwest and south respectively Ground water flow direction in the three deeper hydrologic units appeared to flow northwest to north-northwest • Free product continues to be present in well MW-2, located in the area of the USTs • The highest concentrations of petroleum hydrocarbons detected at the site were present in the ground water monitoring well samples completed in hydrologic units 112 and 4 The highest concentration was from the sample near the former UST release • Lower concentrations of TPH-g and BTEX were measured in the sample collected from well MW-5B The highest concentration of MTBE in unit 4 was detected in the water sample from well MW-5B • Reduced concentrations of petroleum hydrocarbons are present in the ground water monitoring wells completed in the upper portion of hydrologic unit 5 Lower concentrations were detected in the samples from the well completed in the lower portion of hydrologic unit 5 The highest concentration was also from the sample near the former UST release . Sainple MW-6C had a low concentration ofbenzene and sample MW-8B east ofthe site was non-detect The highest concentration of MTBE in unit 5 was detected in the water sample Advanced GeoEnvironmental,Inc