SITE INFORMATION AND CORRESPONDENCE_1993-2003

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Draft Final ROD Memorandum -3- 22 December 1992 DDRW, Sharpe Page Section Subject 27 6.3 Environmental Fate and Transport 47 to 49 7.2.1 to 7.2.4 Alternatives 1A, 1C, 2B and 3D 56 9.0 The Selected Remedy 57 9.1 Ground Water Extraction (Recovery) 62 9.2 Ground Water Treatment 67 9.3 Ground Water Discharge OTHER COMMENTS Compliance With ARARs Section 10.2 of the Draft Final ROD (page 71) discusses the various types of ARARs that the selected remedy will satisfy. Item 8 (page 72) of this Section covers the Board's ARARs. Sharpe has acknowledged that the Porter-Cologne Water Quality Control Act, the Basin Plan and the State Water Resources Control Board (SWRCB) Resolution No. 68-16 (Anti-Degradation Policy) are ARARs. We commend Sharpe for recognizing these State ARARs. However, the discussion in this section is generally too broad and does not accurately reflect the application of these ARARs to the proposed remedial action. In addition to these ARARs, there appears to have been compliance with SWRCB Resolution No. 92-49 in the Draft Final ROD. By letter dated 21 September 1992, we transmitted a copy of Resolution No. 92-49 which requires cleanup to background if technically and economically feasible. Sharpe has proposed compliance with this State ARAR in the following ways: 1. Sharpe has proposed aquifer cleanup levels of 0.5 micrograms per liter (µg/1 ) or non-detect for many of the VOCs as listed in Table 8 (page 45) . Cleanup to non-detect or background complies with Resolution No. 92-49. 2. Sharpe has proposed that the feasibility of achieving the proposed aquifer cleanup levels be evaluated as part of the five year review process (pages 44 and 56) . The five year review process appears to be an ideal mechanism to implement compliance with Resolution No. 92-49 by evaluating the technical and economic feasibility of the cleanup. 3. The 3-D Model predicted that 30 to 40 years would be needed to reduce the TCE concentrations in the ground water to 5.0 µg/l . The model also predicted that a cleanup level of 0.5 µg/l could not be achieved within 100 years after implementation of the remedial action. These model predictions also meet Resolution No. 92-49 in that it would not be economically feasible to reduce the TCE concentrations to 0.5 µg/1 .