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. 10 February 2003 <br /> AGE-NC Project No 98-0511 <br /> Page 3 of 4 <br /> Utilizing EPA Method 8260B, MTBE was detected in the ground water samples collected from <br /> MW-1,MW-3 and MW-5 at concentrations of 2 5 µg/1,20 gg/1 and 110µg/l,respectively 1,2-DCA <br /> was detected In the sample collected from MW-5 at a concentration of 4 2 µg/1 No other fuel <br /> Madditivzes were detected above laboratory reporting limits <br /> Analytical results of ground water samples are summarized on Tables 2 and 3 The inferred lateral <br /> distribution of TPH-g,benzene and MTBE Is illustrated on Figure 4 Copies of the laboratory report <br /> (Cal Tech Laboratory IDs 0212-016-1 through 0212-016-8)and chain-of-custody forms are provided <br /> In Appendix B <br /> 4.0. SUMMARY AND CONCLUSIONS <br /> I Based upon data collected from the site AGE concludes the following <br /> g <br /> • On 03 December 2002 the ground water elevation in the monitored area averaged 1 89 feet <br /> above mean sea level, ground water has Increased approximately 1 7 feet since the previous <br /> quarter The ground water flow direction was Inferred to be generally west-southwestward <br /> under a gradient ranging from 0 002 ft/ft to 0 003 Wft <br /> o TPH-g was detected In ground water samples MW-1, MW-3 and MW-5 at concentrations <br /> r as high as 25,000 Etg/l (MW-1) BTEX compounds were detected In sample MW-1 at <br /> 1 concentrations of 430 µg/l, 240 gg/l, 950 ug/1 and 4,900 gg/l, respectively BTEX <br /> constituents were not detected In samples collected from the other seven monitoring wells <br /> i MTBE was detected In samples MW-1, MW-3 and MW-5 at concentrations of 2 5 µg/l, 20 <br /> µg/1 and 110 µg/l, respectively, the concentrations dectected In samples MW-3 and MW-5 <br /> 1 are above the DHS Maximum Contaminant Level(13 µg/l) for MTBE In drinking water In <br /> i addition, 1,2-DCA was detected at a low concentration In sample MW-5, but the <br /> concentration was above the DHS' MCL In drinking water <br /> I • The detected TPH-g concentration In sample MW-1 Is the highest detected since monitoring <br /> began In March 1999 However, BTEX and MTBE concentrations were stmlllar to <br /> previously reported concentrations <br /> • Hydrocarbon-Impacted ground water Is not defined vertically and laterally along the east <br /> side of the site <br /> E <br /> 5.0 RECOMMENDATIONS <br /> Based upon data collected from the site, AGE recommends <br /> • Continued quarterly ground water monitoring <br /> fAdvanced GcoEnvironmental,Inc <br /> F <br />