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I 12 January 2004 AGE-NC Project No 95-0143 ' Page 4 of 5 I below mean sea level (MSL), a decrease of 0 05 feet since the February 2003 monitoring event The inferred ground water flow direction was toward the northeast with a gradient of 0 002 foot/foot Ground water elevation contours for the May 2003 monitoring event are illustrated in Figure 5 I 32 ANALYTICAL RESULTS OF WATER SAMPLES ' During the May 2003 monitoring event, TPH-g was detected in samples collected from monitoring wells MW-3, MW-7, MW-9, MW-15 and MW-22 at concentrations ranging from 82 µg/1 (MW-7) ' to 190,000 µg/1 (MW-3) Various BTEX compounds were detected in the same wells at concentrations as high as 4,500 µg/1 of benzene, 48,000 µg/1 of toluene, 4,300 µg/1 of ethylbenzene I and 26,000 µg/1 of xylenes, in sample MW-3 Figure 6 illustrates the approximate extent of TPH-g and benzene contamination in ground water Fuel oxygenate MTBE was detected in the sample collected from monitoring well MW-23 at a concentration of 4 9 µg/1 Fuel additive 1,2-DCA was detected in the sample collected from monitoring well MW-14 at a concentration of 2 7 µg/l Target analytes were not detected in the ground water samples collected from monitoring wells MW-6, MW-10, MW-16, MW-17 and MW-24 Analytical results of ground water samples collected during the May 2003 monitoring event are summarized on Table 2 Analytical results of historical ground water samples are summarized on Tables 3 and 4 The laboratory report(MAI Lab Ids 0305122-001 through 0305122-005)acid chain- of-custody hain- ofcustody forms are included in Appendix C I4.0. SUMMARY/CONCLUSIONS Based upon data collected from the site, AGE concludes • An in-situ ozone sparge system was installed at the site during the second quarter 2003 The I sparge system was initiated in July 2003 and operated continuously through the second quarter • The average ground water elevation was 7 52 feet below mean sea level (MSL), a decrease ' of 0 05 feet since the February 2003 monitoring event The inferred ground water flow direction was northeast at a gradient of approximately 0 002 ft/ft • Ground water was within the screened intervals of MW-10, MW-15, MW-16, MW-17, MW-22, MW-23 and MW-24, but ranged from 0 26 feet to 5 85 feet above the screened interval in the other five monitoring wells Advanced GeoEnvironmental,Inc