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7 0 Discussion <br /> • a 71 MW-4 piQ� oa <br />' Wb� 'g} <br /> Groundwater from MW-4 continued to show contamination from TPH-gasoline, oxygenates <br /> and BETX It remains free from motor oil contamination, indicating that MW-4 has not been <br />' affected by contamination from the former used oil USTs TPH-diesel contamination has <br /> T disappeared after a year of contamination The source of the gasoline contamination remains <br /> unknown at this time <br />' 72 Waste Oil USTs <br />' Analysis of MW-2 sampled on 06/21/03 showed contamination from all contaminates analyzed <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 /> has dropped significantly, continuously from 2001 MW-1, MW-3 and MW-4 continue to <br />' I remain free of motor oils contamination <br /> 7.3 Diesel USTs <br />' MW-1 (site of the former diesel USTs) continued to show contamination from diesel although <br /> it has decreased significantly The TPH-diesel contamination level, as shown in Figure 5, <br /> dropped to ND m June 2001, peeked at 72 ppm in S� &Arand has continued to decrease <br />' since then Contamination from THP-gasoline continued at relatively minor levels <br />' Diesel contamination continues to appear in MW-2 MW-4 and MW-3 continued to show no <br /> diesel contamination r <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 R drop from April 2000 to September 2001, a 4 foot <br /> increase to March 2002,4-foot drop to September 2002 and a 1 foot decrease this quarter <br />' 7.4 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 from MW-2, using <br /> disposable bailers and absorbent socks, periodically since that time Approximately 19 1 <br /> gallons of floating oil have been removed through 06/21/03 (Table 3) <br />' 75 Groundwater Flow <br /> The groundwater direction of flow for the area was inferred to bei eeasterly at a gradient of 0 02 <br />' fl/ft(Figure 3) <br /> Figure 4 shows groundwater elevations at various dates Elevations fluctuate over very <br /> significant ranges(up to 5 feet in 9 months), which will affect contamination levels, flow <br /> direction, gradient,etc <br />' 6 <br /> 1 <br />