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r 8.0 CONCLUSIONS Based upon the results of the subsurface investigation performed at Fayette Manufacturing Site, the following conclusions and recommendations can be made. t.. * 1. Subsurface conditions encountered in the borings were similar to those found during the previous subsurface investigation. In the vadose zone, from 0 to approximately 8 feet ''- bis, silty clay was encountered. In the capillary fringe, from approximately 8 feet to 11 feet bgs, generally silty to sandy clay was encountered. From the capillary fringe to the bottom of the borings (up to 15 feet bgs), generally, clayey sand to sandy clay was `r encountered. 2. Groundwater in the uppermost water bearing zone appears to be confined to semi- confined. On September 25, 1996, the depth to water in monitoring wells MW 1, MW2 and MW3 ranged from 7.03 to 8.50 feet below top of well casing elevation. L. Groundwater flow beneath the site is generally northwest with a magnitude of 0.003 ft/ft, or approximately 16 ft/mile. This is similar to last quarter's data. LN 3. Petroleum hydrocarbon-affected soils are present primarily in the vicinity of the capillary fringe at approximately 8 to 12 feet bgs. The highest concentrations of TPHg and benzene are present in soil northwest of the former location of the gasoline USTs. The aereal extent of TPHg and benzene, and the presence of these contaminants in the capillary fringe are indicative of groundwater impact and advection. MTBE was not detected by EPA method 8260 in any soil samples submitted for laboratory analysis. ' 4. Petroleum hydrocarbons in groundwater were detected in grab samples collected from borings SBI, SB2, SB3, SB4A, and S136 and in wells MW-2 and MW-3. Only toluene was detected in the groundwater from borings SB1 and SB3 at concentrations slightly greater than the method detection limits. The plume of TPHg and benzene is north and northwest of the former location of the gasoline USTs. TPHg and benzene were not detected in the groundwater from boring SB7, which was located immediately northwest of the former USTs. In addition, floating product was detected in borings SB2 and FPB-2. The extent of contamination to the south and north is defined. The extent of contamination to the west and the east are inferred and may require additional investigation. MTBE was detected in the groundwater from boring SB3 and ,in monitoring wells MW2 and MW3 and were confirmed by EPA method 8260. +— The wells and borings inside the plume of petroleum hydrocarbon affected groundwater are: wells MW2 and MW3, borings SB2, SB4A, and SB6. Wells and borings outside the plume are: well MWI, and borings SB 1, SB3, SB5 and SB7. The low concentrations of wA95122TIumerpt 17 • SMTH