SITE INFORMATION AND CORRESPONDENCE

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Site-Wide Comprehensive ROD -6- 1 May 1997 DDRW Tracy development and basis for the selected remedies and no further action decisions documented in the ROD. DDRW Tracy should also consider adding an appendix to the ROD of the index to the administrative record to clearly show the documents considered and relied upon to make these decisions. The "as required" language in the statutory determination is too vague with respect to whether or not a five year review will be conducted. 12. Continued Groundwater Monitoring: The ROD should state that groundwater monitoring will be continued on a regular basis at each site proposed for remedial action to provide the data necessary to assess the effectiveness of the remedial action conducted. The remedial alternatives should clarify that the monitoring wells, monitoring frequencies, and duration of monitoring to be conducted will be specified as part of the Well Monitoring Program in accordance with Chapter 15 (see below). In addition, the ROD should clarify that DDRW Tracy will re-evaluate the remedial altematives in cases where constituents of concern are consistently detected in downgradient monitoring wells during a reasonable period after remedial action has been completed, or during a reasonable period of implementing institutional controls as the remedial alternative. As previously stated in our comments on the RI/FS Report, groundwater monitoring must be conducted in accordance with Chapter 15, Division 3, Title 23, CCR. Specifically, 23 CCR Section 2550.10 requires monitoring to determine the effectiveness of corrective actions. Sections 2550.6 and 2580 describe how monitoring must be conducted throughout the closure period, post-closure maintenance period, and compliance period. Pursuant to 23 CCR Section 2550.6(c), monitoring is required for 3 consecutive years from the date of achieving cleanup levels and pursuant to 23 CCR 2580(a), the post-closure maintenance period extends as long as the wastes pose a threat to water quality. Therefore, at sites where remedial action consists of institutional controls which do not include any closure activities, groundwater monitoring may be required to continue for a period longer than three years. The ROD should be modified to include these ARARs for each selected remedy. Specific Comments 1. Section 1.2: The words "several holding ponds" should be replaced by stating that there is one large storm water pond and two sewage lagoons, including a brief description of the purpose of these ponds/lagoons. The last sentence should be moved to the third sentence. 2. Sections 2.0/2.1: The text should include a history of site activities (e.g., contaminated soils associated with waste disposal pits and fire tratining areas etc. ) which led to the current problems. 3. Figure 2-4: This figure shows that evaluation of both implementation and effectiveness of the removal actions which will be conducted prior to the ROD final decision; however, these actions may not be completed prior to completing the ROD. This figure also indicates that the OU-1 full- scale system construction will be evaluated for effectiveness prior to the ROD final decision, but the construction is not scheduled to be complete prior to completing the ROD. The decision box indicating "Evaluate Effectiveness of Removal and Remedial Action Designs" should be deleted. 4. Section 2.2.9: This section states that the criteria which must be met for no further action sites include"No constituents of concern (CDCs) pose actual or potential threats to groundwater