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I AV= ' Working To Restore Nature r. 1992, only downgradient well MW-3 has been sampled. No analytes have been detected in any water sample since July 1992. 4.0 EXISTING CONDITIONS 4.1 Soil f The site is being operated as a cement production plant. Soils beneath the site are fine grained, consisting of clays and silts. Residual soil contamination remains beneath the equipment storage r building. This residual soil contamination is estimated to occupy an area of approximately 685 square feet between the depths of 7 and 11 feet below grade. The volume of contaminated soil is estimated at approximately 102 cubic yards, containing an estimated 15.1 pounds (2.2 gallons) of diesel range hydrocarbons. The affected area is covered with concrete. Rain water cannot leach into the soil of this area. Table 6 presents volume and mass data for the residual contaminated soil. 4.2 Groundwater Trace levels of hydrocarbon analytes were sporadically detected during the early investigative --- history of the site, but have not been detected since a majority of the impacted soil was removed r=l in October 1992. Downgradient well MW3 has been sampled on four occasions subsequent to -ra the completion of excavation. Petroleum hydrocarbon analytes have not been present at or above method detection limits in any of these samples (Table 3). Monitoring and purge logs for the most recent (December 12, 1993) sampling event are included 'f in Appendix I. Laboratory data sheets and chain of custody documentation for this event are tf: r _ also contained in Appendix I. The December 12, 1993 groundwater gradient of 0.004 ft/ft to the north-northwest is depicted on Figure 3. l J OW01951REPORTS1CL012594.PNL 8 tr;