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Review of the Response to Comments on the Draft Explanation of Significant Differences (ESD) to the Site-Wide Comprehensive Record of Decision and Review of the Draft Final ESD, Defense Distribution Depot San Joaquin (DDJC)Tracy Site, Tracy, California April 2004 GENERAL COMMENTS 1. Response to General Comment 4 (dated February 5, 2004): While the response provides the necessary and requested information regarding the human health risks from contamination left in place, there appear to be two revised cleanup standards proposed for DDT. The response and the text in Section 4.3.6 states that "raising the cleanup standard for 4,4'-DDT to 47 micrograms per kilogram (ug/kg) (which represents an estimate cancer risk of 1.6 x 10' and an HQ of 6.5 x 10') is protective of human health." However, the text in Section 4.2.2.3 states that the cleanup standard should be raised to 103 ug/kg based on DI WET results. It appears that both 47 ug/kg and 103 ug/kg are being proposed as the revised cleanup standards for DDT. DI WET results support a cleanup standard of 103 ug/kg, but the human health risk evaluation shows an acceptable risk to DDT from a concentration of 47 ug/kg (the highest concentration left in place). Please clarify which concentration is the correct proposed cleanup standard. If 103 ug/kg is correct, then the human health risk discussion should be updated to show that 103 ug/kg is protective of human health. 2. Response to General Comment 4 (dated March 3, 2004 on the SWMU 8 Data Validation): The comment requested that the statement "It was noted that sample S0146-SO-323 was requested for validation. However, this sample was not analyzed by the laboratory" be removed or clarified. A response to this comment was not included in the RTC table. Please provide a response that includes the section number or page number where this statement was removed or clarified. SPECIFIC COMMENT 1. Response to Specific Comment 5 (dated February 5, 2004): The response states that the excavation at SWMU 8 was backfilled due to the unlikelihood of meeting the pesticide cleanup standards because the edge of the low level detections of pesticides in areal soil was not found. Section 4.1.2.5 of the ESD states that the excavation at SWMU 8 was more than double the design volume and was discontinued because funding was exhausted. However, inadequate funding is not a sufficient basis for not meeting ROD cleanup standards. A statement should be added to Section 4.1.2.5. that, as explained in Table 4-3, remaining levels of Dieldrin and DDT in soil are well below ROD cleanup 1