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iH t 05'May 2004 ' AGE-NC Project No. 95-0106 Page Kof 4 „ ' MTBE was detected in the.ground water sample collected from well MW-1 at a concentration of 680 n/L. This detection should be confirmed and is not typical for the.chemistry of the„ground . water at the,site. 1,2-DCA was'detected at,concentrations of 29'µg/L and 8.6 µglL'in the ground water,samplcs ' collected from MW-1 and MW-4, respectively. TAME was detected at a concentration of 27 µglL in the sample's collected from MW=1.. No additional analytes were detected at or above laboratory detection limits in wells MW-1-and MW-4. No analytes were detected at or above laboratory detection limits in wells MW-2, MW-3, MW-4; MW-5, MW-6 (upper), MW-6 (lower) and MW-7. Analytical results'of ground water samples are summarized in Table 2. The laboratory report (CTEL Project No: CT214-03121.26)1 QA/QC and chain-of-custody are'included.in Appendix C. , 4.0. SUMMARY AND CONCLUSIONS ' ' The following conclusions were drawn from the±results of the-site investigation: • The ground water flow direction was generally northward' on 16 December 2003, and,' '• gradients were calculated to range from 0.006 feet/fee toward the northwest to 0.007 feet/feet toward the northeast. Ground water elevations increased slightly but continue to flow in a ' northerly direction. • TPH-g was detected in ground water samples from monitoring well MW=4, located down-. gradient-off-site from the formenUST excavation;and well MW-1 located just north of the 1, former.UST area. - • BTEX compounds were detected in the water samples collected from MW-1 and MW-4. The . concentrations of benzene in the ground'Water sample collected from Well MW-4 exceeds ' maxirnum'contaminant level MCL for drinking water.,Benzene was the State of California (MCL) g not detected this quarter in the samples collected,from vve11 MW-1. It is the first time since 1998 that benzene was not'detected_in well MW-1:. MTBE Was detected in the water sample collected from'MW=1, the concentration detected exceeds the MCL for MTBE in-drinking-water. This detection should be confirmed and is 1 not typical for the chemistry of the ground at the site: dw • 1,2-DCA was detected Ifor the second time in the groundwater sample collected from MW-1 - - ' and for the first time.in the samples collected from well -MW-4; the concentration of ,•1,2-DCA exceeds the MCL for'drinking water.; Advanced GeoEnvironmental,Inc..