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I7 0 Discussion <br /> 7 1 MW-4 <br /> 3 <br /> Groundwater from MW-4 continued to show contamination from TPH-gasoline, oxygenates } <br /> and BETX The TPH-gasolme contamination continues to decrease It remains free from <br /> motor oil contamination, indicating that MW-4 has not been affected by contamination from the <br /> I former used oil USTs TPH-diesel contamination has disappeared after a year of <br /> contamination The source of the gasoline contamination remains unknown at this time <br /> 7 2 Waste Oil USTs <br /> I Analysis of MW-2 sampled on 09/30/03 showed contamination from all contaminates analyzed <br /> I <br /> MW-2 continues to show contamination from motor oils as reflected in the amount of floating <br /> oil removed during the past quarter and the analytical results The level of oil contamination <br /> l has dropped continuously from 2001 MW-I, MW-3 and MW-4 continue to remain free of <br /> 1 motor oils contamination <br /> 73 Diesel USTs <br /> IMW-1 (site of the Former diesel USTs) continued to show contamination from diesel The i <br /> TPH-diesel contamination level, as shown in Figure 5, dropped to ND in June 2001, peeked at <br /> 72 ppm in S pt"�( and has continued to decrease since then Contamination from THP- <br /> gasoline no longer appears 41n <br /> Diesel contamination continues to appear in MW-2 MW-4 and MW-3 continued to show no 1 <br /> i diesel contamination E <br /> The reversal of trends over the past 3 years may have resulted from the extreme changes in <br /> groundwater elevation (Figure 4), a 7 foot drop from April 2000 to September 2001, a 4 foot <br /> increase to March 2002, 4 foot drop to September 2002 and a 2 5 foot decrease this quarter <br /> 74 Floating Oil <br /> A September 1998 sample of groundwater monitoring well MW-2 found black, floating oil that <br /> appeared to be typical of used motor oil Floating oil has been removed froin MW-2, using <br /> disposable bailers and absorbent socks, periodically since that time Approximately 19 6 <br /> gallons of floating oil have been removed through 09/30/03 (Table 3) I <br /> 75 Groundwater Flow � <br /> The groundwater direction of flow for the area was inferred to be easterly at a gradient of <br /> 0 00155 ft/ft(Figure 3) <br /> I <br /> Figure 4 shows groundwater elevations at various dates Elevations fluctuate over very <br /> I € significant ranges (up to 5 feet in 9 months), which will affect contamination levels, flow <br /> direction, gradient, etc <br /> 6 <br />