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}A �. descriptions free each soil type encountered on the drilling (Appendix V . Field analysis of soil samples using the PTA recorded the organic vapor readings in samples from monitoring well h;.ghest borings 1 and 4. Similarly field inspection of samples detected the strongest product odors from these two wells with slight odors noted at increasing depths in well borings at greater distances. Selected soil samples were laboratory analyzed to determine -- Benzene, Toluene, Xylene and total volatile hydrocarbon concentr- ations. Analyses were performed by purge and trap gas chromato- graphy, EPA Method 5030, with flame ionization detection and photoionization detection as per EPA Methods 8015 and 8020. The laboratory test results are presented in Appendix XII. The soil sample collected at a depth of 19 feet in well bare 3 contained "` the highest contaminant level= 75 mg/kg (ppm) total volatile P-0 hydrocarbons. Concentrations far samples from well boxings 9, 2 # and 4 were 68 ppm (rpt 25 ft. ) , 33 ppm (at 24 ft. ), and 22 ppm (at 14 ft. ) respectively. ) GROUNDWATER MONITORING � Periodic monitoring Of wells at the site has continued since their initial installations in May 1986 tr,rough August 1986 r' (Table 1). Groundwater monitoring to determine the presence of free product and the depth of the liquid interface was conducted in accordance with Groundwater Technology's Standard Operating -- Procedure 8 (A},pendix 11 ) . The surveyed well head elevations and the monitoring data for August 191 1986 allowed the con- . struction of a groundwater gradient map (Figure 8). water table w* elevation hydrogravhs for 8 of the groundwater monitoring wells in the study area were drafted through the August 25, 1986 monitoring (Appendix TV) . Changes in product thickness with time 16