SITE INFORMATION AND CORRESPONDENCE

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KLEINFELDER File No. 20-3978-01.W10 July 26, 1997 3. Additionally, Kleinfelder recommends that all State of California Department of Conservation Division of Oil and Gas guidance documents and regulations for development in former well/pit locations be carefully followed. 4.9 Potential Landfill Locations (File No. 20-3978-O1.WR9) Based on the results of the subsurface assessment conducted in this area, Kleinfelder had the following conclusions detailed in our report "Investigation of Suspected Landfill Locations, (Phase I ESA Recommendation No. 11), Former Spreckels Sugar Plant, Manteca, California" dated February 24, 1997: 1. Investigation of seven suspected landfill locations revealed two disposal areas, one containing a lime waste (Site B disposal area), and the second containing construction debris (Site C disposal area). Site B disposal area is approximately 11,000 square feet in area and contains an estimated 2,800 cubic yards of debris mixed with soil and lime. Site C disposal area has a surface area of approximately 26,000 square feet and contain as estimated 8,600 cubic yard of debris. 2. Soil samples collected beneath the Site C disposal area did not show evidence of contamination. Groundwater samples revealed possible elevation of inorganic constituents downgradient of both disposal areas although the degree of elevation was not exceptionally high. Several volatile organic constituents were detected in MW-CDOI downgradient of Site C disposal area although these results are not definitive as there are other possible sources. Methane gas was detected at both disposal areas in low concentrations. The highest concentration was found in the Site C disposal area but that concentration was still below the lower explosive limit for methane. Varying amounts of near surface debris was found in other areas (Site A, Site D, Site E) but this debris does not appear to be extensive enough to be classified as a disposal area. 3. Of the two closure methods considered (in-place closure and clean closure), in-place closure had the lowest cost. Note that very conservative assumptions were made in the in-place closure costing and the actual cost is likely to be lower than that estimated here. Although clean closure was more expensive initially, it has the advantage of removing the waste from the property thereby decrease uncertainty and liability associated with owning a waste disposal site in the future. 10-3978-01.W1011017L155 Page 25 of 50 Copyright 1997,Kleinfelder,Inc.