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' 10 October 2000 <br /> AGE-NC Project No 97-0249 <br />' Page 4 of 5 <br />' • Ground water flow direction for the area bound by Three B's Truck Plaza wells MW-1 <br /> through MW-6 and Flag City Chevron wells MW-7, MW-12A and MW-13A was generally <br /> toward the west-southwest at a gradient of 0 004 ft/ft, or approximately 21 feet per mile <br />' (Figure 3), due to the low gradient at the site, slight variations in ground water measurements <br /> or changes of recharge/discharge of the local ground water could greatly modify ground <br /> water flow direction <br /> 1 • Ground water flow direction at the site may have been influenced by pumping of the Three <br /> B's Truck Plaza domestic drinking water well <br />' • The ground water elevation at the site was within the screened intervals of wells MW-1 <br /> through MW-6 <br /> I • Ground water elevation at the site decreased an average 4 85 feet from the May 2000 ground <br /> water monitoring event to the August 2000 ground water monitoring event <br /> • The lateral extent of the dissolved petroleum hydrocarbon plume is not known toward the <br />' south, southwest, west, northwest, north and northeast of the current area bound by wells <br /> MW-1 through MW-6, the vertical extent is not known in any direction <br /> 10 • The elevated petroleum hydrocarbon concentrations detected in water samples collected from <br /> wells MW-1, MW-2, MW-3 (screened between 5 and 25 feet bsg) suggest that these wells <br /> may be screened within or near the "core area" of the dissolved petroleum hydrocarbon <br /> plume The area of greatest dissolved petroleum hydrocarbon-impact was observed in the <br /> area near MW-3 (Figure 4) <br /> • Elevated concentrations of dissolved petroleum hydrocarbons were detected in the samples <br /> collected from well MW-6, the TPH-g and TPH-d contour maps (Figures 4 and 5) suggest <br /> a secondary dissolved petroleum hydrocarbon plume in the area of MW-6 <br /> • A low concentration of MTBE was detected in the sample collected from well MW-4 <br /> • Laboratory results of grab ground water samples suggest that there is no MTBE-impact to <br /> the Three B's Truck Plaza domestic drinking water well (DW-1) at this time <br /> • AGE suspects the ethanol detected in DW-I (May 2000)"grab"ground water sample was due <br /> I to the coated bentonite pellets utilized during construction of Flag City Chevron well <br /> MW-13 <br /> I <br /> 5.0. RECOMMENDATIONS <br /> IBased upon data collected during August 2000, AGE recommends <br /> Advanced GeoEnvironmental,Inc <br />