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.. TERRA VAC both the Chevron and Kwikee Foods (Kwikee) sites in the first quarter 1995 (the last available data for the Kwikee site). The hydrocarbon plume east of Franklin Avenue should be defined, pending any investigations conducted by the responsible party of the Kwikee site. Records for the Boulevard Auto site indicate that two USTs were removed from the site. Records also state that a hydrocarbon sheen was observed on the groundwater surface in the UST excavation (File search conducted by Gettler-Ryan, Inc., January 15, 1996). Available soil analytical data indicate hydrocarbon impact to vadose zone soils. Benzene concentrations reported in the unsaturated zone range from 230 parts per million (ppm), detected at a depth of 13 feet, during the UST removal in 1988 to 0.012 ppm in well MW-3 at a depth of 10 feet. Wells MW-4, MW-5, and MW-9 through MW-12 did not contain detectable concentrations of benzene. Isoconcentration maps illustrating the lateral extent of benzene impacted soil are presented as Figures 5 and 6. Historical depth to water measurements show groundwater fluctuations ranging from a high of approximately 7.5 feet below grade (151 quarter 1997) to a low of approximately 23 feet below grade (4`h quarter 1992). Lithology within the unsaturated zone characterized by fine grain, low conductivity soils, silts and clays, with interbedded lenses of sands with varying amounts of fine grain soils. Coarser grained, moderately conductive sands with varying amounts of fine grain soils characterize lithology within the saturated zone, below a depth of 20 feet. Well surveys conducted by EA Engineering, Science, and Technology, Inc. (EA) and Gettler-Ryan, Inc. did not identify groundwater receptors within a radius of 1000 feet. As stated above the leading edge of the dissolved plume appears to have stabilized approximately 160 feet down-gradient of the site. _ 2.0 SCOPE OF WORK As requested by PHS-EHD, additional groundwater quality data will be collected in the northwest and southwest corners of the site (Figure 7). One additional groundwater sample will be collected from the center of Franklin Avenue, east of well MW-l. This sample will be used to evaluate dissolved benzene concentrations between wells MW-1 and the Kwikee Foods site. Groundwater samples will be collected using push probe technology. This will complete dissolved benzene plume delineation at the site. Soil data from previous Chevron investigations indicate that potential hydrocarbon sources are confined to areas adjacent to the former UST complex. In order to further define benzene impact to unsaturated soil, considered to be potential inoculation sources, additional soil samples will have to be collected. This will be accomplished with the use of a Geoprobe. Each probe will be advanced to a depth equal to historical low water. Approximate sample locations are illustrated on Figure 7. At a minimum, at least three Project No. 30-0239 August 14, 1997 2 primed on recycled paper NW