SITE INFORMATION AND CORRESPONDENCE 1995-2004

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James L. Tjosvold,P.E. August 7, 1996 Page 7 Pages 7-2 and 8-1 of the RI report. These guidelines provide that receptors consist of humans and ecological receptors such as plants, animals, and aquatic life. Groundwater is one of the media and is not considered a receptor by these guidelines. Comment: 4. Page ES-2, Executive Summary As part of its remedial approach to ground water, PG&E recommends implementing the soil remedy to be presented in the final feasibility study and remedial action plan. The current soil remedy proposed consists of treating four soil source areas within Area I to minimize COPC migration to ground water. The State has not agreed to the definition of the source areas nor has it agreed to allow no further definition in non-source areas. Based on the bench study, the current soil remedy proposed will mobilize COPC to the ground water. The proposed remedial alternative will comply with State Water Resources Control Board Resolution No. 92-49 only if the wastes left in the ground will not release contaminants at concentrations that will impact the ground water, or if it is infeasible to eliminate all potential impacts, will not affect the beneficial uses of the ground water. Response: 4. See the response to DTSC's comment 3. Comment: 5. Page 10, Environmental Risk Assessment The report states that the discharge of surface run off has not occurred from the surface water collection system since a sump was installed. The fate of the sump contents should be described in the report. Response: 5. The sump and surface water collection system were described in detail in the Environmental Risk Assessment which was included in the approved Final Remedial Investigation and Risk Assessment Report, August 1993. Attached find pages from the RI report describing this system. The Phase IV report included a brief summary of the Risk Assessment results as part of the background on the site. Comment: 6. Page 12, Nearby Environmental Investigations The report states that the Fire Department has not tested Zones B and C, and MW-14 (which is located on Commerce Street and downgradient of the Fire Department and upgradient of the PG&E) has had detectable concentrations of benzene and total petroleum hydrocarbons (TPH). I concur that the Fire Department has not tested Zones B and C. However, based on current information, it is not clear if PG&E is really downgradient from the Fire Department. As suggested in Item 2 above, the Fire Department is cross gradient of PG&E in Zone A. Also, the fuel petroleum hydrocarbon contamination in MW-14 is questionable. MW-14 had detectable benzene and TPH as diesel (TPHd) in November 1994, which was the