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i <br /> southwesterly from MW-4 to MW-3 at a gradient of 0 01 ft/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 /> IA review of Figure 4, Groundwater Elevation, shows that wells MW-1, MW-3 and MW-4 <br /> moved in tandem from April 2000 through September 2001, with MW-2 generally following the <br /> Isame trend, but, moving higher or lower somewhat randomly This is due to the difficulty of <br /> measuring groundwater elevations in MW-2 because of floating hydrocarbons in this well <br /> MW-3 elevations differed from MW-1 in December 1999 and again in February 2003 The <br /> significance of this is unclear at this time <br /> 50 CONCLUSIONS AND RECOMMENDATIONS <br /> 5.9 Conclusions <br /> IThe 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 The contamination does not appear in <br /> any of the other three wells <br /> The former diesel USTs caused moderate contamination of the soil and groundwater adjacent to <br /> the tanks Diesel contamination was detected in MW-2 (northeast of MW-1) and MW-3 <br /> I (southeast of MW-1) in April 2000 1 UJY- <br /> coritammuon-was=-detected-again Since <br /> that time, the diesel contamination in MW-3 and MW-4 has disappeared The contamination in <br /> MW-2 remains although it is consistently decreasing The diesel contamination in MW-1 (site of <br /> Ithe former diesel USTs) remains The presence in MW-1 and MW-2 indicates that diesel <br /> contamination is still affecting groundwater quality (Figure 5) <br /> MW-4 was installed down gradient (at that time) from MW-2 to detect possible movement of <br /> Iused motor oil in the groundwater from the contamination source (former waste oil USTs at <br /> I <br /> Environeenng,Inc - Project No 03 00218 Page 6 <br /> I <br />