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1 <br /> contamination exists between MW Nos 1 and 2 near the site's eastern property <br /> ' line fence <br /> The site's groundwater flow, based on current Monitoring Well information is <br /> northward, at a gradient averaging 0 002 FT/FT declining at an average <br /> bearing of N 20-25 deg E Please reference ATTACHMENT 5, GROUNDWATER <br /> ' GRADIENT AND BEARING CALCUATIONS <br /> Soil contamination was not found during installation of MW Nos 5 and 6, <br /> r however, levels less than 0 3 mg/kg of diesel were found in the well's <br /> groundwater samples <br /> r On November 5, 2003 four new holes were pushed using a CPT rig to ground <br /> water to sample outlying groundwater to determine if the new sampling points <br /> were beyond the underground hydrocarbon plume A fifth hole was pushed to a <br /> ' depth deeper than the expected water table but no groundwater was <br /> encountered <br /> 1 Groundwater contamination between 50 to 55 FT bgs exists Diminishing <br /> hydrocarbon contamination was found north of the site's property during the <br /> November CPT borings While the leading edge waits to be defined, the original <br /> underground storage tanks (USTs) source has been removed, contaminant <br /> levels are low near the north property line fence and the closest operating offsite <br /> r down gradient well is at least 600 FT away Additionally, residual soil <br /> contamination possibly contributing to the contamination has been identified and <br /> a portion is not covered by structures, removal may be anticipated <br /> r <br /> A summary of all ground water sampling events is included REFERENCE <br /> rATTACHMENT 2, SUMMARY OF LAB RESULTS included with the report <br /> A copy of Del-Tech Geotechnical Support Services field 29 December 2003 <br /> ' monitoring report is attached <br /> Sampling to establish a "clean line" further out from the source is intended but is not <br /> r practical until ground bearing capacity improves late in spring 2004 Construction of <br /> temporary access for an additional round of CPT bonngs was pursued in January but <br /> the ground was found to be too wet and too unstable for passage of a 25 Ton CPT <br /> r rig The use of planking, additional rock fill or other methods of supporting a CPT rig <br /> is expensive and still carries a risk of trapping the ng and potential of an accident <br /> The encountered levels of hydrocarbon (diesel) were between <50ug/1 and 260 ug/I <br /> ' at depth of about 60 FT bgs in the plume during the November CPT sampling <br /> r 3 <br /> r <br />