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' 03 December 2004 . AGE-NC Project No 99-0637 ' Page 3 of 4 ' Ground water flow was inferred to be flowing toward the northwest,away from the former UST area at an average gradient of 0 004 ft/ft Figure 3 illustrates the contoured ground water elevations as measured on 17 August 2004 1 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES ' TPH-g,TPH-d,BTEX and the fuel additives,with the exception of MTBE,were not detected in any of the ground water samples collected ' MTBE was detected in the ground water samples collected from wells MW-1, MW-4, MW-5 and MW-9 at concentrations ranging from 1 3 µg/1 in well MW-9 to 1,300 µg/1 in well MW-5 A map ' depicting the approximate distribution of dissolved MTBE is presented on Figure 4 No other analytes were detected at or above laboratory reporting limits in the ground water samples The analytical results of ground water samples are summarized in Tables 2 and 3 The laboratory report (MAI Work Order 0408242), QA/QC report and chain of custody form are included in Appendix C GeoTracker confirmation pages of the submitted laboratory electronic deliverable format (EDF) files are included in Appendix D 33 OZONE INJECTION PILOT TEST I Ozone injection began at the site on 31 August 2004 Currently the ozone system injects ozone for a 2 hour duration into one ozone injection point at a time After completing a cycle through the nine ozone wells, the ozone injection ceases for 2 hours prior to beginning the next cycle The injection rate is approximately 8 0 psi Field measurements are summarized in Table 4 I4.0. SUMMARY AND CONCLUSIONS The following conclusions were drawn from the results of this investigation • The ground water elevations ranged from 9 63 feet to 10 13 feet above MSL Ground water flow was inferred to be flowing toward the northwest, away from the former UST area at an average gradient of 0 004 ft/ft • TPH-g, TPH-d, BTEX and fuel additives, with the exception of MTBE, were not detected Iin any of the ground water samples collected from the site Advanced Geo Envi ron mental,Inc I