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Mr. Cecchini October 21, 1992 Page 3 After the initial nutrient application, the spread soil will be worked with a eight to ten inch disc once every two weeks for a period of approximately one month. This initial month of soil working is proposed to take place during the month of November. It is anticipated that the winter season, occurring after December 1, 1992, will prevent microbes in the soil from optimum effectiveness, therefore after December 1, the soil will be left spread until spring of 1993 (Assume April). The soil will then be worked for a period of one month (the month of April). Soil sampling at a rate of one composite sample of four for every 100 cubic yards of soil will be performed in late April after the spring treatments. The four composite soil samples will be analyzed for Extractable Petroleum Hydrocarbons as Diesel. ESE does not believe it is necessary to analyze the soil for.,TVH and BTEX since nondetectable results were reported during the August 1992 sampling of the stockpile. If analytical results show concentrations of EPH below the proposed cleanup goal, then soil remediation will be assumed complete. A report documenting soil remediation, sampling and analytical results will be issued and site closure requested. The report will request that the soil remain on site and used as fill. Clean up Goal ESE proposes a clean up goal of 10 mg/Kg EPH for the remediated soil. This clean up goal is proposed for the soil to remain onsite after remediation is complete. The site is located within a ground water depression resulting from extensive ground water pumping of aquifers in the Stockton area ( San Joaquin County Flood Control and Water Conservation District Semi Annual Groundwater Report, Spring 1990). First ground water at the site ( as measured in four monitoring wells on the adjacent site in August 1992) is currently at 90 feet below ground surface. A water well, located at the site was reported installed in the 1970's. In approximately 1987, water levels in that well were measured at 67 feet below ground surface (Central Valley Regional Water Quality Control Board, personnel communication James Brathove). ESE assumes that the ground water level of 67 feet below ground surface represents a non-drought water level for this area. The nearest surface water bodies are the Calaveras River, approximately one mile north of the site,and the Stockton Diverting Canal, approximately one half mile southeast of the site. Monitoring wells drilled on the adjacent site showed native alluvial soils of silty clay and clayey silt to depths of fifty feet. Based on the deep ( greater than fifty feet) ground water occurrence in this area, lack of nearby surface waters, and relatively tight surface soils in this area, ESE believes that the proposed cleanup goal of 10 mg/kg for the remediated soil will not impact adjacent soils or groundwater at the site. Upon reaching the cleanup goal, soil can be used for fill at the site.