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Draft OU-1 ROD Comments -2- 2 July 1993 DDRW, Tracy 76. Section 7.3.2.3 The State believes that since the effluent is to be monitored there is no need to monitor the influent. After a brief discussion, EPA concurred. Comments of similar nature appear several more times is EPA's comments. CLARIFICATION The statement that the State believes that there is no need to monitor the influent is incorrect. Influent and effluent monitoring.must be conducted and will be required for the chemicals of concern in the Waste Discharge Requirements (WDRs) that will be revised for OU-1. We believe that dieldrin, like arsenic, should not have effluent limits established at this time. However, monitoring must be required for these constituents. Effluent limits for these constituents should be established once the comprehensive site-wide RI is completed. More data must be collected from the OU-1 treatment system to determine if treatment for dieldrin is possible or necessary. In the interim, we believe that the disposal system for the OU-1 Remedial Action must be designed to insure that reinjection of the treated groundwater does not degrade the receiving water quality of lower zones. However, we are willing to agree to establish effluent limits for dieldrin based on the health based Risk Assessment. The last sentence in Section 7.3.2.3 should be edited to state that the operation and maintenance of the treatment system for compliance with the effluent limits will be performed to assure that degradation of the aquifer by disposal of the treated groundwater will not occur. RWQCB Comments of June 4, 1993 5. Third Paragraph EPA questioned the purpose of completing an analysis (to determine if it is technically and economically feasible to cleanup the aquifer to background) if this ROD is setting cleanup levels based on primary MCLS. The State believes that this is still a State requirement. EPA stated that this requirement appears to be "outside" of this ROD. The State concurred. CLARIFICATION We do not concur that the analysis referenced above appears to be "outside" of this ROD. DDRW, Tracy has already agreed to conduct the analysis. We believe this commitment should be recorded in the ROD. This issue with respect to Applicable or Relevant and Appropriate Requirements (ARARs) is being referred to the EPA's and Board's legal staff for resolution.