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i r e � 15 ,Apnl 2004 • AGE-NC Project No 95-0142 Page 3 of 4 - 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was not detected in samples collected from wells Benzene and ethylbenzene were detected in the sample collected from well MW-5 at concentrations of 0 90 microgram per liter (µg11) and 12 pg/l, respectively The fuel additive MTBE was detected in wells MW-5 and MW-7 at concentrations of 3 6 µg/l and 17 µg/l, respectively ' The analytical results are summarized on Tables 2 and 3 The laboratory report (MAI Laboratory I D Nos 0402229), quality assurance/quality control (QA/QC) report and chain-of-custody form ' are included in Appendix C I40 CONCLUSIONS Based upon data collected from the site during the current and preceding ground water monitoring ' events, AGE concludes • Ground water flow direction appeared to be toward the northwest in the monitored zone lie defined by the well network,this gradient was similar to gradients during fluctuations of the ground water elevation Historically,the highest concentration of dissolved petroleum hydrocarbons was in the area ' of the former UST TK1-90 (well VW-1) TPH-g and BTEX concentrations have steadily declined to non-detect in the samples collected from the deep screened well MW-6(screened ' 70 to 80 feet bsg) Presently, MW-6 is screened approximately 45 feet below the surface of first-encountered ground water • Monitoring wells MW-6, MW-7 and MW-8 are screened approximately 45 feet below the ' surface of first-encountered ground water MTBE has been detected in the samples collected from well MW-7 for,six consecutive quarters, but has not been detected in the samples collected from well MW-6, beneath the former UST area 19 The distribution of MTBE suggests that the MTBE plume has laterally migrated to well MW-5 and vertically migrated to well MW-7 t 1 � , ' Advanced Geo Environmental,[nc F ,