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14 January 2004 , <br /> AGE-NC Project No. 98-0520 <br /> ' Page 3 of 4 <br /> Ethylbenzene and xylenes'were detected in sample MW-5 at the following concentration 4.2 µg/l, <br /> ' and 3.2 µg/l, respectively. Benzene and toluene were not detected at or above laboratory reporting. <br /> 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. CT214-0308124) 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 27 August 2003 the ground water elevation at the site averaged approximately'12.21 feet <br /> ' above MSL showing an elevation decrease of approximately 2:11 feet since the last <br /> monitoring event,the lowest water level since monitoring began in 1999.Groundwater flow <br /> lie was toward the northwest at an average gradient of 0.002 foot/foot. The ground water flow <br /> direction has been consistently northwest since the initiation of ground water monitoring in <br /> -December 1999. <br /> ' TPH-g concentrations decreased in samples'collected from wells MW-3 through MW-10. <br /> TPH-g was not detected in samples MW-4 and MW-9 for the fourth consecutive monitoring <br /> event.TPH-g has not been detected in deep-screened well MW-6 since the well was installed <br /> in December 2001. <br /> • Ethylbenzene, and total xylenes were detected in MW-5; all the concentrations were below <br /> ' the DHS Maximum Contaminant Levels (MCLs) for drinking water. <br /> • The vertical extent of impacted ground waterhasbeen defined. Impacted ground water does <br /> not extend beyond.45 feet bsg. <br /> • The lateral extent of petroleum hydrocarbon-impacted ground water has not been adequately <br /> defined west of the former USTs. <br /> 5.0. RECOMMENDATIONS <br /> 1 • • <br /> Based upon data collected from the site, AGE recommends. continued quarterly ground water <br />' monitoring. The next quarterly monitoring event is scheduled for December 2003. <br /> Advanced GeoEnvironmental,Inc. <br />