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SITE CONTAMINATION WORK PLAN ELECTRO DELTA 821 S.Wilson Way Stockton,California 1.0 INTRODUCTION This work plan has been prepared by Upgradient Environmental Consultants on behalf of Mr. Tom Nichols under contract #98036. The purpose of the work plan is to specify the equipment and procedures that will be used to investigate the vertical extent of soluble lead in the soil beneath the Electro Delta property located at 821 S. Wilson Way in Stockton (Figure 1). The investigation was requested by the San Joaquin County Public Health Services Agency, Environmental Health Division (PHS/EHD), in verbal and written communications to the owners of the property. Under the authority of the Central Valley Regional Water Quality Control Board, regulatory oversight for the investigation has been assigned to PHS/EHD and the site has been placed in its Local Oversight Program. 2.011ACKGROUND It is our understanding that a 550-gallon underground storage tank (UST) was removed on December 18, 1985 from the property (Figure 2). The property was owned and operated by Caterpillar Tractor as early as the 1930's, and it is possible that the UST was installed during Caterpillar's ownership. Apparently, the UST was used to store leaded gasoline, because a concentration of 407 mg/kg (parts per million: ppm) was detected in the soil sample from beneath the UST when it was removed (data supplied by PHS/EHD). The removal was performed by Kleinfelder&Associates and witnessed by personnel from PHS/EHD. 3.0 SCOPE OF WORK We propose to drill a boring through the former tank cavity to a depth of 15 feet. The depth to water is presently estimated to be between 35 and 40 feet, which is probably only slightly deeper than its historical high level. Mitchell Environmental Drilling will use a truck-mounted CME-75 drilling rig equipped with 8-inch-diameter hollow-stem augers, and Upgradient will supervise the work. A soil sample will be collected through the augers in a brass sleeve and preserved for laboratory analysis. The boring will be backfilled to the surface with a cement slurry. Cuttings will be placed on plastic sheeting pending laboratory analysis of the sample. The sample will be transported to Excelchem Analytical Laboratories and analyzed for soluble lead using the California WET test. After the laboratory results have been received, Upgradient will prepare a letter report summarizing the results of the analysis. The field and laboratory procedures are summarized below.