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t 23 July 2004 • AGE-NC Project No 99-0624 ' Page 7 of 8 3 4 ANALYTICAL RESULTS OF GROUND WATER SAMPLES ' TPH-g was detectedin the water samples collected from wells MW 1 through MW3 at concentrations of_110 µg/1, 10,000 µg/1 and 300 µg11, respectively Benzene, ethylbenzene and xylenes were ' detected in the sample collected from well MW2 a't concentrations of 9 7 µg/1, 5 5 µg/1 and 20 µg/l, respectively ' The fuel additive MTBE was detected in samples from wells MW1, MW2, MW3 and MW7 at concentrations ranging between 21 µg11 (MW7) and 9,900 µg/1 (MW2) TAME was detected in samples from wells MW2 and MW3 at concentrations of 46 µg/1 and 2 1 µg/l, respectively TBA ' was detected in sample MW2 at a concentration of 19 µg/1 No other constituents of concern were detected at or above laboratory reporting limits in the analyzcd ' samples Current and historical analytical results of ground water monitoring well samples are summarized in Table 3 The laboratory report (CTEL Project No CT214-0405082) and chain-of- custody forms are presented in Appendix D GeoTracker confirmation pages of the submitted ' laboratory EDF files are included in Appendix F lie 4.0. SUMMARY AND CONCLUSIONS ' The following conclusions were drawn from the results of this investigation • The depth to ground water at the site was approximately 53-54 feet below surface grade, or ' approximately 15 12 to 15 48 feet below mean sea level • Ground water flow direction in the area of wells MW 1 through MW6 was inferred to be towards the southwest at an approximate gradient of 0 003 ft/ft Due to the low hydraulic ' gradient at the site, slight variations in ground water measurements or changes of recharge/discharge of the local ground water could greatly modify the inferred ground water flow direction ' 0 TPH-g was detected in the ground water samples collected from wells MW1, MW2 and MW3 at concentrations of 110 µg11, 10,000'µg/1, and 300 µg/1, respectively, between ' November 1999 and May 2004 TPH-g concentrations have fluctuated from 140 µg/1 to as high as 33,000 µg/1 in samples from well MW2 ' MTBE was detected in ground water samples from wells MW 1, MW2, MW3 and MW7 at concentrations as high as 9,900 µg/1 (MW2) • The lateral extent of MTBE-impacted ground water has been relatively defined to in the UST area An iso-concentration map depicting the approximate distribution of dissolved MTBE • is presented to Figure 4 Advanced GeoEnviron mental,Inc 1