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Antonia K. J. Vorster -2- 5 August 1988 <br /> Requirements guidance document. <br /> 2. KEI's proposal calls for excavating about 6, 000 cubic yards of <br /> soil contaminated with gasoline related compounds and methylene <br /> chloride, aerating it, and backfilling it into the excavation. The soil <br /> cleanup level recommended in this proposal is less than 10 ppm Total <br /> Petroleum Hydrocarbons. <br /> According to soil investigation work done by Kleinfelder, the amount of <br /> contaminated soil exceeds 6, 000 cubic yards. The Problem Assessment <br /> Workplan should include a Soil Remediation Plan that details how the <br /> entire amount of contaminated soil will be cleaned up to a level of less <br /> than .l ppm TPH. A cleanup level of 1 ppm is necessary to eliminate the <br /> source of ground water contamination. In-situ treatment should be <br /> explored since the excavation necessary to remove all the contaminated <br /> soil will have to be over 30 feet deep. Land availability and air <br /> quality standards make the feasibility of such an excavation at this <br /> location questionable. <br /> If excavation is selected as the cleanup method, the Soil Remediation <br /> Plan should include at a minimum, an excavation/aeration plan approved <br /> by the San Joaquin County Air Pollution Control District and a sampling <br /> plan for the excavated soils and the boundaries of the excavation. <br /> Conclusions <br /> A Problem Assessment Workplan should be submitted which includes a <br /> detailed plan and time schedule for completion of the plume definition <br /> phase of the ground water investigation. Implementation and completion <br /> of the Problem Assessment work must result in complete delineation of <br /> the ground water pollution and an assessment of remedial action <br /> alternatives. <br /> A Soil Remediation Plan should be submitted along with the Problem <br /> Assessment Workplan that includes a description of and time schedule for <br /> mitigation of the entire source of ground water pollution (contaminated <br /> soils) . The cleanup level goal is 1 ppm total petroleum hydrocarbons. <br /> Unocal has not been responsive to our previous requests to complete the <br /> Problem Assessment phase of this project and has apparently backed off <br /> from the interim ground water cleanup and soil venting plans which we <br /> spent considerable time on and approved of in our 4 March 1988 letter. <br /> We should consider enforcement action if Unocal fails to comply with the <br /> work requested in this memo. <br /> DLB <br />