SITE INFORMATION AND CORRESPONDENCE_1992

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A• gTATE OF CALIFORNIA • CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD— RETE WILSON, Go e, o, CENTRAL VALLEY REGION p ' . 3443 ROUTIER ROAD, SUITE A C'�i,�,. �i E SACRAMENTO. CA 95827-3098 '(�L�- fi , R PHONE: (916) 361-5600 lmo 8 FAX (916) 361-5686 APR 2 4 1992 ENVIRONMENTAL HEALTH PERMIT/SERViU5 17 April 1992 Mr. Abel Haines Environmental Protection Office Bldg. S-4, Sharpe Location P. 0. Box 960001 Stockton, CA 95296-0250 DRAFT SOILS FEASIBILITY STUDY (FS) REPORT, DEFENSE DISTRIBUTION REGION WEST (DDRW), SHARPE, SAN JOAQUIN COUNTY We have reviewed the Draft Soils FS Report submitted on 18 February 1992. The Draft Soils FS Report was accompanied by three supporting documents: Problem Assessment Report (PAR) for Underground Storage Tanks (USTs) , Vapor Extraction Pilot Study and the Soils Risk Assessment Report. We have conducted a detailed review of all of the documents except the Soils Risk Assessment Report for which we have deferred review to the Department of Toxic Substances Control (DTSC) . Enclosed are three memorandums which separately discuss our reviews of the Soils FS Report, the PAR for USTs, and the Vapor Extraction Pilot Study. We are very concerned with the lack of proposals for further investigation and remediation of contaminated soils in the Draft Soils FS Report. With respect to the FS, we find that the investigation of the source areas is inadequate. New source areas have been identified with the investigation of the USTs and additional investigation will be required to define the extent of contamination in the soils and ground water. The investigations presented in the Draft Soils FS Report are also inconsistent with the level of investigation being performed at DDRW, Tracy. Cleanup levels were proposed only for two contaminants despite the fact that other wastes were present in the soils in high and often hazardous concentrations. The cleanup levels for lead and TICE are unacceptable because ground water quality may still continue to degrade. The ground water investigation has focused primarily on contamination by solvents and the pending site-wide, comprehensive ground water Record of Decision (ROD) and remedial action are intended only to address ground water contamination by volatile organic constituents (VOCs) . Information submitted in the Draft Soils FS Report shows that ground water has been contaminated with semi-VOCs, polychlorinated biphenyls (PCBs), heavy metals and other potential contaminants, not yet identified due to the inadequate investigation of waste management units (WMUs) and USTs. The upcoming ROD cannot be considered comprehensive because it will not address all ground water contamination at DDRW, Sharpe. Unless the