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I I10 February 2005 ,• AGE-NC Project No 96-0263 ' Page 3 of 4 ' Benzene was detected in water samples MW-2, MW-5 and MW-7 at concentrations ranging from 14 gg/l in MW-5 to 640 µg/1 in MW-7 Toluene, ethylbenzene and total xylenes were detected in samples MW-2, MW-5 and MW-7 at concentrations as high as 59 µg/1, 180 µg11 and 350 gg/l, ' respectively(MW-7) MTBE was detected in samples MW-2,MW-4,MW-5,MW-7 and MW-8 at concentrations ranging ' from 24 gg/l (MW-8) to 43,000 gg/l (MW-7) TAME and 1,2-DCA were detected in the sample collected from well MW-7 at concentrations of 48 gg/l and 14 µg/l, respectively No other fuel additives were detected in the ground water samples collected from the site ' The current and past ground water sample analytical results are summarized in Tables 2 and 3 Copies of the laboratory report (CTEL Project No CT214-0408199), quality assurance/quality ' control (QA/QC) report and chain of custody forms are in Appendix C GeoTracker confirmation pages of the submitted laboratory electronic deliverable format (EDF) files are included in Appendix D 3 3 OZONE INJECTION PILOT TEST Ozone infection began at the site on 01 June 2004 The ozone infection operational protocol, as established by ozone units designer manufactures, follows the recommended two-hour ozone ' injection cycle at each sparge-point The injection rate is approximately 10 pounds per squar inch (psi)to displace the ground water within the sparge wells and no greater than 2 cubic feet per minute ' (CFM) to infect the ozone After completing a cycle through all nine ozone wells, the ozone infection ceases for a 2-hour mechanical hiatus, after which, the infection cycle through all of the sparge wells restarts 4.0. SUMMARY AND CONCLUSIONS Based on the results of this investigation, AGE concludes that IDepth to ground water ranged from 7 18 feet to 8 31 feet below the tops of the well casings Ground water elevations at the site ranged from 28 60 feet above MSL in well MW-9 to 29 42 feet above MSL in well MW-11 The ground water at the site was inferred to be flowing to the north-northwest at an average gradient of 0 005 foot/foot • Target analytes, including TPH-g,BTEX components, MTBE and/or TAME were detected in ground water samples collected from wells MW-2, MW-4, MW-5, MW-7 and MW-8 Detected concentrations of target analytes were generally consistent with previous results ' Advanced GeoEnvironmental,Inc