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' 30 April 2000 AGE-NC Project No 97-0333 ' Page 4 of 5 ' 4.0. SUMMARY AND CONCLUSIONS The implications from the January 2001 ground water monitoring event are as follows ' • Ground water flow direction at the site was inferred to be towards the north at a gradient of 0 001 or less, due to the low gradient at the site, slight variations in ground water ' measurements or changes of recharge/discharge of the local ground water could greatly modify ground water flow direction • The ground water elevation at the site was within the screened intervals of wells MW-1, ' MW-2,MW-3,MW-4 and MW-5 which should yield samples fully representative of shallow ground water conditions ' • Ground water elevations increased at the site an average 0 70 feet between the October 2000 and the January 2001 ground water monitoring events, the increase of ground water elevations is probably due to seasonal fluctuation ' • The core of the dissolved petroleum hydrocarbon plume appears to be located in the area of MW-2 (screened between 12 and 32 feet bsg), analysis of ground water samples collected Mfrom MW-2 suggest the core of the plume is impacted by TPH-g, BTEX, and MTBE • Substantial concentrations of dissolved TAME have previously been detected in water samples collected from well MW-1 and a grab ground water sample collected from. P-3 ' indicating that there is a limited area impacted with TAME in ground water in the area assessed ' • Substantial concentrations of PCE were detected in water samples collected from MW-4, low concentrations of TCE were detected in water samples collected from MW-5, PCE and TCE are chlorinated solvents that are often associated with dry cleaning operations ' • A substantial concentration of hexachlorobutadiene was detected in the water sample collected from MW-2 while lesser concentrations were detected at MW-1 ' • A substantial concentration of 1,2,3-tnchlorobenzene was detected In the water sample collected from MW-2 ' 0 The vertical extent of dissolved petroleum hydrocarbons is not known at the site, Figures 5 and 6 in Cone Penetrometer Testing Site Investigation - Fourth Quarter 2000, dated 07 February 2001 depict dissolved petroleum hydrocarbon-impact at depths up to 137 feet bsg, ' • The lateral extent of the dissolved petroleum hydrocarbon plume is not fully defined toward the northwest, north, east and southeast of the current area bound by wells MW-1 MW-2 MW-3, MW-4 and MW-5 (Figure 4) Advanced Geok.nvironmental Inc