SITE INFORMATION AND CORRESPONDENCE_1992

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Draft Ground Water ROD Memorandum -5- 21 May 1992 DDRW, Sharpe wastewater treatment plant and the oxidation and holding ponds which were formerly used for the disposal of the industrial wastes. The figure also indicates an area of elevated concentrations of bromacil in MW-407A (773 Ag/1 ) . However, the map does not depict concentrations higher than 100 µg/1 . Figure 11 should be corrected for the Final ROD. Selected Remedy. Section 9.0 discusses the selected remedy. In this section it is stated that the goal of the remedial action is to restore ground water to its beneficial "reuse" (page 51) . We concur with the goal of the remedial action is restoration of the beneficial uses of the aquifer. However, it is unclear how beneficial uses of the aquifer will be restored if the aquifer cleanup level for many of the ground water contaminants is only the Primary MCL, or health based cleanup levels. The beneficial use of drinking water goal would not be met unless taste and odor as well as health-based water quality criteria are reflected in the aquifer cleanup levels. Ground Water Extraction for 16 Years. The ROD states that the selected remedy will include ground water extraction for a period of 16 years. The ROD should clarify that 16 years is the estimate of how long it will take to restore the aquifer to the cleanup levels and that extraction may continue longer until the aquifer cleanup levels are achieved. Ground Water Disposal . Sharpe has presented a good discussion in the ROD on ground water disposal and has given considerable thought and planning to disposal compared to the original plans presented in the Focused FS. The ROD states that the injection wells will be gravity fed. It is unclear if the historical high for ground water was considered in these preliminary designs of the injection system. In addition, decisions regarding the disposal of the ground water cannot be made final until the Alternative Water Supply Study is reviewed. The review of this secondary document was agreed to be extended during the May 1992 Project Manager's Meeting to 6 July 1992. The Draft Final ROD will need to consider the comments on the Alternative Water Supply Study. Compliance with Applicable or Relevant and Appropriate Requirements (ARARs) . The ROD indicates that the selected treatment alternative and the associated disposal of the treated ground water will comply with the Board's NPDES permit. Sharpe will be required to comply with the receiving water limits established in the Inland Surface Water Plan. The monthly monitoring reports indicate that Sharpe's effluent is exceeding the limit of 5 µg/1 for arsenic. We plan to address this issue under a separate cover letter. The ROD should include a table listing all of the identified ARARs. We have most recently identified our ARARs in our 17 April 1992 letter on the Soils FS Report. In addition, the ROD did not identify any location-specific ARARs. Chapter 15, Title 23 of the California Code of Regulations, contains location-, action-, and chemical-specific ARARs and must be identified in the ROD. The section on Statutory Determination is inadequate because it does not discuss previously identified ARARs. Section 8.6 discusses Compliance with ARARs and Cleanup Levels. This section needs to state what the ARARs are for each alternative and must specifically show how compliance with each of the ARARs will be achieved.