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EXECUTIVE SUMMARY <br /> ' The objectives of the project were to further define the lateral extent of impacted groundwater, <br /> and to expand the groundwater monitoring capability at the site To achieve these objectives, two <br /> additional groundwater table monitoring wells (MW-5 and MW-6) were permitted, installed, and <br /> ' surveyed Groundwater in the new and existing wells was monitored, sampled and analyzed <br /> Consistent with previous investigations, the uppermost 30 feet of soil at MW-5 and MW-6 consists <br /> ' of a massive sandy soil sequence interbedded with intervals of clay, silt and fine sand mixtures <br /> Based on previous cone penetration test (CPT) borings, the soil between 30 and 150 feet consists <br /> of a massive sequence of clay and silt soils interrupted by discontinuous intervals of sand and <br /> ' gravel soils <br /> The static depth to the groundwater table, as measured in the six monitoring wells, ranged from <br /> 19 23 feet below ground surface (bgs) in MW-6 to 21 11 feet bgs in MW-4 The resulting <br /> ' groundwater surface appears as an irregular plane dipping to the northeast at a gradient of <br /> approximately 0 0071 foot/foot Between September 26 and December 19, 2002, the <br /> groundwater surface rose an average of 2 43 feet, the groundwater gradient increased slightly <br /> ' from 0 060 to 0 071 foot/foot, and the groundwater flow direction remained toward the northeast <br /> The soil samples collected at 20 and 30 feet from MW-5 and MW-6 did not contain detectable <br /> ' concentrations of gasoline compounds From the six groundwater monitoring wells, the sample <br /> collected from MW-2 contained the highest concentrations of gasoline compounds 510 µg11 of <br /> TPH-as-gasoline, 12 µg/l of benzene, 16 µg11 of toluene 49 µg11 of ethylbenzene, 37 µg11 of <br /> xylenes, and 10 µg/I of MTBE The only other detectable concentrations of gasoline compounds <br /> were 53 µg/I of TPH-as-gasoline in MW-1 and 55 µg/1 of TPH-as-gasoline in MW-3 The <br /> groundwater sample collected from the on-site water supply well did not contain detectable <br /> ' concentrations of gasoline compounds <br /> Results of this investigation confirmed that the direction of groundwater flow is toward the <br /> ' northeast, and that impacted soil and groundwater appears defined to the vicinity of the site <br /> Based on these conclusions, Ramage Environmental recommends that the six monitoring wells <br /> and on-site water supply well continue to be monitored and sampled on a quarterly basis The <br /> next monitoring event is scheduled for March 2003 <br /> 4 <br />