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' 02 April 2002 • AGE-NC Project No 95-0103 Page 3 of 4 I 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was detected in samples from monitoring wells MW-1, MW-3, MW-4, MW-5 and MW-7 ' at concentrations of 4,600 microgram per liter(µg/1), 2,500 µg/l, 1,200 µg/1, 340 µg/1 and 170 µg11, respectively Benzene was detected in the water samples from wells MW-1,MW-3 and MW-4 at a maximum concentration of 3,800µg11(MW-4) The other BTEX compounds(toluene,ethylbenzene and xylenes) were detected in samples MW-1,MW-3,MW-4,MW-5 and MW-7, with the highest concentration(3 3 µg/1 toluene,320µg/1 ethylbenzene and 430µg/1 total xylene)occurring in sample MW-4 MTBE DIPE and TBA were detected in the water samples from well MW-1 at concentrations of 42 µg/l, 6 9 µg/1 and 85 µg/1, respectively The analytical results of current and previous monitoring well samples are summarized in Tables 2 ' and 3 The laboratory report of the current ground water sampling data (CalTech IDs 0201-136-1 through -7), quality assurance and quality control (QA/QC) data and chain-of-custody form are included in Appendix B ' • 4.0. DISCUSSION/CONCLUSIONS Based on the analytical results from this investigation, AGE concludes the following • The average ground water level at the site decreased 1 3 feet since the monitoring event in September The map of ground water contours indicates a ground water trough flowing ' towards the east • The ground water table in monitoring wells MW-1 through MW-4 was approximately one ' to three feet above the top of the screened interval • High concentrations of benzene were detected this quarter in on-site-momtonng wells MW-1 and MW-4 at high concentrations and at low concentrations off-site (MW-3) ' * The fuel oxygenates MTBE, DT-PE and TBA, were detected in the samples from MW-1 ' Advanced CeoEnvironmental,Inc 1