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' RESULTS OF INVESTIGATION Site Geolo Sediments encountered while drilling suggest the site is underlain by three units The upper ' unit, located from the surface to depths of approximately 25 feet bgs, is dominantly silty sand with some thin silt and clay layers encountered at various depths between 12 and 24 feet bgs in ' two of the borings The middle unit located from between 25 and 42 to 43 feet bgs, is dominantly well graded sand The lower unit, encountered in two of the borings, is located ' from between 42 to 43 feet and 45 feet bgs, the maximum depth explored, is dominantly clay. First groundwater beneath the site was encountered during drilling between 26 and 30 feet bgs Site Hydrogeology ' The depth to groundwater beneath the site historically has ranged from approximately 26 39 to 29 73 feet bgs The water level data were used to develop the elevation contour map (Figure 3) The average hydraulic gradient on August 16, 1995, was calculated to be 0 007 ft/ft or approximately 35 ft/mile The groundwater elevation at the site decreased approximately 0 14 ' feet since March 31, 1995 The groundwater elevations are contained in Table 2 ' Residual Hydrocarbon in Soil The results of laboratory analyses of soil samples collected from the soil borings (MW-4, MW-5 ' and MW-6) contained no measurable concentrations of TPHg or BTEX Table 2 shows the analytical results for soil samples collected from the new soil borings and the previous borings advanced by AquaGeoSciences Inc in July 1993 ' Dissolved Hydrocarbons in Groundwater Results of laboratory analyses of groundwater samples collected from wells MW-1 through MW- ' 6 on August 16, 1995 are contained in Table 3 Wells MW-1, MW-2, MW-4 and MW-5 contain no measurable concentrations of TPHg or BTEX Well MW-3 has contained elevated levels of TPHg and BTEX Well MW-6, located downgradient from well MW-3, contains low to moderate levels of TPHg and BTEX W \15007MPEPORMPAR 5 • SMTH