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9 <br /> • 04 August 2006 <br /> AGE-NC Project No 96-0263 <br /> Page 3 of 4 <br /> 200 micrograms per liter(pg/1), 600 pg/l, 1,000 pg/l, and 1,500 pg/l, respectively <br /> One or more BTEX compounds were detected in the water samples from MW-1,M W-2,MW-7,and <br /> MW-8 at maximum concentrations of 16 pg/l benzene(MW-7), 4 5 pg/I toluene (MW-8), 20 pg/l <br /> ethylbenzene (MW-2),and 77 µg/l total xylenes (MW-8) <br /> MTBE was detected in sample MW-7 at a concentration of 650 pg/l <br /> No other analytes of concern were detected in the ground water samples collected from the site The <br /> current and past ground water sample analytical results are summarized in Tables 2 and 3 Copies <br /> of the laboratory report (CTEL Project No CT214-0603084), quality assurance/quality control <br /> (QA/QC) report and chain of custody forms are in Appendix C <br /> 3 3 OZONE INJECTION <br /> Ozone injection began at the site on 01 ,lune 2004 The ozone injection operational protocol during <br /> the quarter included 2-hour ozone injection cycles at each sparge-injection-point The injection rate <br /> is approximately 10 pounds per squar inch(psi)to displace the ground water within the sparge wells <br /> and no greater than 2 cubic feet per hour(CFH) to inject the ozone <br /> After completing a cycle through all nine ozone wells, the ozone injection ceases for a 2-hour <br /> mechanical hiatus, after which the injection cycle through all of the sparge wells restarts Field logs <br /> are included in Appendix B <br /> 4.0. SUMMARY AND CONCLUSIONS <br /> Based on the results of this investigation, AGE concludes that <br /> • Depth to ground water ranged from 7 11 feet to 8 27 feet below the tops of the well casings <br /> Ground water elevations at the site ranged from 28 59 feet above MSL in well MW-9 to <br /> 29 46 feet above MSL in well MW-I 1 <br /> • The ground water at the site was inferred to be flowing north-northwest at an gradients <br /> ranging from 0 003 ft/ft on the southern portion of the property to 0 008 ft/ft on the northern <br /> portion <br /> • Target analytes, including TPH-g, BTEX components, and MTBE were detected in ground <br /> water samples collected from wells MW-1, MW-2, MW-7, and MW-8 Previously, ground <br /> water samples from well MW-8 had been non-detect since August 2004 <br /> Advanced GeoF nvironmental,Inc <br />