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•r Groundwater Contour Map and Flow Gradient A groundwater contour map to a known datum was prepared for the data listed in Table 1 above (see Figure 1) The groundwater flow direction was to the north northwesterly under a calculated gradient of 0 0026 The flow direction is consistent with historic observed trends, and remains relatively flat Overall groundwater levels appear to have dropped slightly from the previous quarter Groundwater mounds have formed around MW-9 in the past, however,contours do not indicate a mound present at this time(see Figure 1) Chemical Analytical Methods and Results Nine groundwater samples were analyzed using EPA Methods 5030/8015, 602 and 8260 for Total Petroleum Hydrocarbons as Gasoline (TPHG), Benzene, Toluene, Ethylbenzene and Xylene (BTEX) and fuel oxygenates including Methyl-tert-butyl-ether (MTBE), Tert-Butyl Alcohol (TBA), Di-Isopropyl Ether (DIPE), Ethyl tert-butyl ether (ETBE), Tert-Amyl Methyl Ether TAME), 1,2-Dichloroethane (1,2-DCA) and Ethylene Dibromide (EDB) The analytical results of the groundwater samples for this sampling event are listed in the attached table Discussion Groundwater flow direction is north northeasterly at a low flow gradient, which is consistent with historically observed trends Contaminants were observed in the Wells MW-2, MW-3, MW-6 and MW-9 Contaminants were • not observed inMW-1, MW-4, MW-5, MW-7 or MW-8 Contaminant concentrations declined in Wells MW-2, MW-6, MW-9 but rose in well MW-6 Concentrations continue to vary which indicates that desorbtion mfluences the concentration levels observed depending upon fluctuating aquifer water levels and the contaminant absorbtion to soil (see discussions in previous reports) These concentration variation trends are attributed to fluctuations in water levels and contaminant desorbtion from the aquifer sediment/soil in the immediate vicinity of the wells, and fluctuations are expected to continue In our opinion,these data indicate a relatively stabilized plume Conclusions and Recommendations Groundwater flow direction was northerly under a low calculated gradient In our opinion, the mapped contaminant plume appears stable in the center of the site, this relative plume stability on-site has been a historic site trend The overall historic site trend appears to be a fluctuating slow concentration decline PHS EHD has requested additional subsurface investigation in the vicinity of MW-9 and Wright has prepared a work plan for that work The site is scheduled for continued quarterly monitoring at this tune Cox and Cox Quarterly Monitoring Well Sampling Report Page 2 Wright Environmental Services Inc August 16,2000