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08-'05-96 WIN 16'41 FAX 510 842 6615 CPL HELP H.O. @1004 L)RA 'r #2 beneath the project area is prohibited for use as domestic or municipal supply by the City of Tracy for reasons unrelated to the presence of degraded crude oil. Subsurface soil at a nearby property known as the Dividend property has been affected by the same petroleum hydrocarbon as that found at HighieUMonterosso. CPL has performed extensile site investigations, and Geoniatrix performed a hurnar health risk assessment for-the Dividend property, dated 24 May 1995, that was submitted to the DTSC. The purpose of the health risk assessment was to evaluate the potential health risks to future site residents associated with residual Cude oil/Bunker C oil present in subsurface soil along the southern boundary of the Dividend property. The health risk assessment was conducted in accordance with the DTSC's Human Health Screening Evaluation as described in the Preliminary )endangerment Assessment Guidance Manual The evaluation required the assumption that the affected soil is exposed at the ground surface and that residents are exposed to the maximum concentrations of chemicals detected in the soil. The health risk assessment concluded that potential human exposure to the crude oil/Bunker C oil-affected soil would not result in unacceptable health risks to future on-site residents. The DTSC approved the conclusions of the human health risk assessment in a memorandum dated 3 November 1995. Based on the risk assessment results for the Dividend property and the fact that concentrations of petroleum at the Highiet/Monterosso parcel are lower than those at the Dividend property (1100 ppm vs. 7500 ppm), the residual petroleum at the Highiet/Manterosso parcel should pose no significant risk to future on-site residents. SJCEHD concurred with this conclusion and issued a site closure letter on SOIL MANAGEMENT PLAN This management plan is intended to address options available for handling the degraded cnidc oil/Bunker C oil-affected soil if it is excavated during construction of the subdivision or when placing/repairing below--grade utilities. The location of known areas of affected soil are depicted KAWP000W1499\S01L1'LAN Doc(W()FL)) �