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ormer Lyoth Loading Station 4 8 October 1998 Chevron Pipe Line, San Joaquin Co. Compliance of Chevron's Technical Approach with State Water Resources Control Board (State Water Board) Resolution Nos. 9249 and 88-63 1. State Water Board Resolution No. 92-49 requires contaminated sites to be cleaned up to background conditions unless it is technologically or economically infeasible to do so. Chevron's approach should include a demonstration that it is technologically or economically infeasible to clean up soil and groundwater contamination to nondetect levels. 2. State Water Board Resolution No. 88-63 states that all surface waters and groundwaters of the State to be suitable or potentially suitable for municipal or domestic water supply, and these waters are designated as such in the Regional Board's Basin Plan. Resolution No. 88-63 allows certain exceptions to this designation. To demonstrate that the shallow groundwater beneath a site is not suitable for drinking water supply, Chevron's approach should include showing that the groundwater meets the exemption requirements under Resolution 88-63 and that there is no connection between the shallow and deeper groundwater. Summary 1. The vertical extent of contamination at the following locations is undefined: B-9, B-16, B-21, GP-3, and MW-2. Due to the inconsistency in sampling, other locations may also lack definition. At GP- 3, the lateral extent of crude oil soil contamination is defined, but not the lateral extent of contamination by TPHd and PAHs. The lateral extent of crude oil, TPHd, and PAH soil contamination at GP-9 and GP-10 needs definition. 2. The vertical extent of groundwater contamination at MW-2, MW-6, and potentially at MW-7, GP- and P and GP-10 needs to be defined. 3. The threat to water quality is not being adequately addressed because the test methods for PAHs are not sufficiently sensitive to allow their detection below the water quality objectives. To address this concern, Chevron should analyze both water and filtered material (such as that retained during silica gel cleanup) to determine the total PAHs and their speciation. 4. The technical approach should be revised and made consistent with State Water Board Resolution Nos. 88-63 and 9249 and Appendix B of the Tri-Regional Recommendations. 5. Chevron should obtain Board approval prior to cessation of the monitoring program. PSI:psi/Isb.U:lyoth.mem