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Sept 2001 and has remained relatively constant since Contamination from THP-gasoline <br />' remains constant this quarter / <br />' Diesel contamination continues to appear in MW-2 MW-4 showed no diesel contamination this <br /> quarter after four quarters of contamination <br /> The reversal of trends shown in this, and the prior quarter sampling, may have resulted from the <br /> extreme changes in groundwater elevation (Figure 4), a 7 ft drop from April 2000 to September <br />' 2001, a 4 foot increase to March 2002 and a 4-foot drop to September 2002 <br /> t4.4 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 16 5 gallons <br /> of floating oil have been removed through 11 September 2002 (Table 3) <br /> 4.5 Groundwater Flow <br /> lie <br /> The groundwater direction of flow for the area was inferred to be southeasterly at a gradient of <br /> 0 01 ft/ft to 0 004 ft/ft (Figure 3) <br /> The flow gradient increased slightly from the previous quarter <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, etc <br /> 5.0 CONCLUSIONS AND RECOMMENDATIONS <br /> 5.1 Conclusion <br /> The former waste oil USTs caused significant contamination of the soil and groundwater <br /> immediately adjacent to the tanks Substantial quantities of oil have been removed from MW-2, <br /> however, contamination remains The used oil appears to move very slowly through the soil and <br /> in relatively close proximity to the former USTs location and contamination does not appear in <br /> • <br /> Environeenng,Inc Project No 02 00917 Page 5 <br />