SITE INFORMATION AND CORRESPONDENCE_1992

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. MEMORANDUM • CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD - CENTRAL VALLEY REGION 3443 Routier Road, Suite A Phone: (916) 361-5600 Sacramento, CA 95827-3098 ATSS Phone: 8-495-5600 TO: Antonia K. J. Vorster FROM: Camilla Williams Senior WRC Engineer Engineering Geologist DATE: 21 September 1992 SIGNATURE: SUBJECT: REVIEW OF THE WORK PLAN ADDENDUM, DEFENSE DISTRIBUTION REGION WEST (DDRW), SHARPE, SAN JOAQUIN COUNTY I have reviewed the Work Plan Addendum for the DDRW, Sharpe site submitted on 22 July 1992. The Work Plan was prepared by Environmental Science and Engineering (ESE) for the U. S. Army Toxic and Hazardous Materials Agency (USATHAMA) . This Work Plan was prepared to address the need for additional soils and ground water investigation at specific waste management units (WMUs) and underground storage tank (UST) sites. Sharpe investigated the non-fuel USTs, including waste oil , waste solvent and pesticide USTs, with the fuel USTs after the completion of the Remedial Investigation (RI) for Operable Unit No. 1 (OU-1) . These data were submitted in the February 1992 Draft Feasibility Study (FS) Report. Concentrations of polychlorinated biphenyls (PCBs) and heavy metals (chromium and nickel ) exceeded the respective Primary Maximum Contaminant Levels (MCLS) in the ground water samples collected from newly installed monitor wells near USTs containing waste oils. In the 7 May 1992 Project Manager's Meeting, it was agreed that additional time would be needed for Sharpe to conduct an investigation for the non-fuel USTs and that this investigation could be incorporated into the Soils Record of Decision (ROD), scheduled for signing in July 1994. This ROD would be site-wide and would incorporate all ground water contamination. Sharpe submitted a response document, dated 20 July 1992, to all of the agencies comments on the FS Report. Sharpe did prepare responses to our comments on the Vapor Extraction Pilot Study Report and on the Draft Feasibility Study Report, but failed to provide any response to our comments on the Problem Assessment Report (PAR) for USTs. The Work Plan proposes additional work for the investigation of six non-fuel USTs, the pesticide mix area and WMU No. 26 and proposes to conduct a long-term (three month) vapor extraction system (VES) pilot study. The strengths of the Work Plan are the figures and the background information submitted in the Work Plan. Sharpe addressed a few of our major concerns from the Draft FS Report. However, there are several concerns that remain outstanding from the Draft FS Report which were not addressed by Sharpe. My major concerns and other specific comments on this document are discussed in more detail below. MAJOR CONCERNS 1 . There are several non-fuel USTs for which additional investigation for potential soils or ground water contamination was not proposed. We consider source investigation and remediation to be critical in the overall cleanup of the site. If sources are left in-place, contamination will continue to leach to the ground water, reducing the cleanup remedy merely to a containment remedy for ground water.