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05 September 2003 <br /> AGE-NC Project No. 98-0520 <br /> Page 3 of 4 <br />' Ethylbenzene was detected in samples MW-2, MW-3 and MW-5 at a maximum concentration of <br /> 120 gg/1, and xylenes were detected in well MW-5 at a concentration of 58 pg/l. Benzene and <br /> toluene were not detected at or above laboratory reporting limits in any of the ground water samples. <br />' No other analytes were detected at or above laboratory reporting limits in the ground water samples <br /> collected. Analytical results of ground water samples are summarized on Table 2. The laboratory <br />' report (CTEL Lab Project. No. CT214-0306054) and chain-of-custody forms are included in <br /> Appendix C. <br /> 4.0. SUMMARY AND CONCLUSIONS <br />' Based upon data collected from the site, AGE concludes: <br /> • On 09 June 2003 the ground water elevation at the site averaged approximately 14.33 feet <br /> above MSL showing an elevation decrease of approximately 1.99 feet since the last <br /> monitoring event. Ground water flow was northwest at an average gradient of 0.002 feet/feet <br /> which is slightly higher than last quarter. The ground water flow direction has been <br /> 1i consistently northwest since the initiation of ground water monitoring in December 1999. <br /> • TPH-g concentrations remained relatively stable in samples collected from wells MW-1 <br /> through MW-10,however levels are still well below historical highs.TPH-g was not detected <br /> in samples MW-4 and MW-9 for the third consecutive monitoring event.TPH-g has not been <br /> detected in deep-screened well MW-6 since the well was installed in December 2001. <br /> • Ethylbenzene, and total xylenes were detected in MW-5 and only ethylbenzene was detected <br /> in MW-2 and MW-3. All the concentrations were below the DHS Maximum Contaminant <br />' Levels (MCLs) for drinking water. <br /> • The vertical extent of impacted,ground water has been defined..Impacted ground water does <br /> not extend beyond 45 feet bsg. <br />' The lateral extent ofpetroleum hydrocarbon-impacted ground water has not been adequately <br /> defined northwest of the former USTs. <br /> 1 . <br />' 5.0. RECOMMENDATIONS <br /> Based upon data collected from the site, AGE recommends continued quarterly ground water <br />' monitoring. The next quarterly monitoring event is scheduled for September 2003. <br /> Advanced GeoEnvironmental,Inc. <br />