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%W 15 June 2009 AGE-NC Project No.05-1306 ti.. Page 10 of 33 Less consistently, ground water samples have been reported to show detections of TPH-g. TPH-g concentrations ranging between 320 gg/l and 370,000 gg/l, were reported in well MW-2 between August 1998 and August 2005 (well removed during remedial excavation). Well MW-3 had five reported detections of TPH-g between August 1998 and June 2004 at concentrations ranging between 120 µg11 and 1,400 gg/l. Well MW-4 had eight reported detections of TPH-g between June 2000 and May 2007 at concentrations ranging between 110 µg11 and 940 µg11. More significantly, detectable concentrations of TPH-g have not been reported in wells MW-1,MW-2R, MW-5, MW-6, MW-7, MW-10, MW-11, and MW-12. Infrequent detections of one or more of the aromatic hydrocarbon compounds (benzene, toluene, ethylbenzene, and xylenes, collectively referred to as BTEX) also have been reported at low concentrations ranging between 0.63 gg/1 to 600µg/l.A relatively significant and isolated detection for total xylene was reported at 19,000 µg11, during a low ground water level sampling event in which TPH-g was detected at significant concentrations.However,results from this sampling round appear to be anomalous when compared to all historical data. Well MW-2 had two reported .r concentrations ofbenzene,three reported concentration of toluene,and three reported concentrations of xylenes.Well MW-3 had two reported concentrations of toluene and one reported concentration of xylenes. Well MW-4 had two reported concentrations of xylenes, and well MW-7 and one a. reported concentration of toluene.Importantly,detectable concentrations ofBTEX compounds have not been reported in wells MW-1,MW-2R,MW-5,MW-6,MW-10,MW-11,and MW-12.Methyl tertiary-butyl ether(MTBE)has not been reported as detected in any ground water samples collected i- from the site. With the exception of the June 2004 ground water sampling event,where reported laboratory results are considered anomalous and not representative of historic conditions, and the initial sampling of well MW-1, ground water samples collected from perimeter monitoring wells MW-I and MW-6 have not contained detectable concentrations of petroleum hydrocarbon constituents. Monitoring well MW-5 was reported as having low TPH concentrations in June and November/December 2004. Comparison of the historic ground water sampling events to those from June 2004 demonstrate the anomalous nature of the June 2004 results. Figures 9 and 10 depict ground water and grab ground water sample locations and the estimated extent of dissolved TPH-d concentrations in cross sectional view; Figures 11 and 12 depict the estimated lateral extent of dissolved TPH-d impacted ground water in a plan view. TPH-d trends are included in Appendix 1. A free product sample was collected from MW-2 in August 2004. The laboratory characterized the sample as a substantially degraded middle distillate such as diesel#2 that lacked the common water t— soluble, aromatic components such as benzene,toluene, ethylbenzene, and xylenes(BTEX),and is thus considered relatively insoluble in water. Advanced GeoEnvironmental,Inc.