SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

t 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: 23 August 1991 SIGNATURE: N �� SUBJECT: REVIEW OF INVESTIGATION AND REMEDIATION PLAN FOR THE NEW SUBSISTENCE WAREHOUSE, DEFENSE DISTRIBUTION REGION WEST (DDRW), TRACY, SAN JOAQUIN COUNTY I have reviewed the Investigation and Remediation Plan for the subsistence warehouse excavation at the south end of the DDRW, Tracy site. Due to the time critical nature of this investigation, in that, the DDRW, Tracy will pay penalties to the construction contractor for delays in the schedule, I have agreed to expedite my review of this document. I provided my verbal comments to Mr. Marshall Cloud in a telephone conversation earlier today. My comments and concerns are summarized below. 1 . The document needs to be revised to reflect the name change for the Department of Health Services to the Department of Toxic Substances Control (DTSC) . 2. Page 3. Section 1.4 indicates that the warehouse is approximately 270 feet by 250 feet. However, the excavation is larger than the area of the warehouse and therefore, the size of the warehouse excavation needs to be referenced. I had been previously informed that the size of the excavation was approximately 900 beet by 400 feet. The size of the area of concern needs to be clarified. 3. Page 4. Section 2.0 states the objectives of the investigation. The objectives are incomplete because protection of water quality is not listed as an objective. One the warehouse is constructed, additional remediation of the subsoils to protect ground water would be difficult. Tracy needs to consider that the beneficial uses of the ground water (which potentially could have/had been impacted by the wastes discovered in the excavation) include more than just a potential source of drinking water. The beneficial uses of the ground water include domestic, municipal , industrial and agricultural supply and are listed in Finding No. 12 of Waste Discharge Requirements (WDRs) Order No. 90-275. 4. Page 8. Section 3.4 indicates that a minimum of 1267 cubic yards (cy) of contaminated soil must be excavated. It is unknown how this amount was determined. In addition, 1267 cy of excavated soil may not be an adequate amount of soil as a removal action to protect water quality. Depending on the concentrations of potential contaminants in the subsoils, Tracy may need to excavate more than 1267 cy of contaminated soil . 5. Page 8. Section 3.5 indicates that the drums are to be sampled in-place prior to removal from the excavation. In a telephone conference call on 13 August 1991 between the Environmental Protection Agency (EPA) , the OTSC, the Regional Board and Tracy, it was agreed that the drums and other potential hot spots could be removed for sampling on a non-time critical basis.