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HomeMy WebLinkAboutMINUTES - 06241986 - 2.6 THE BOARD OF SUPERVISORS OF CONTRA COSTA COUNTY, CALIFORNIA Adopted this Order on June 24 , 1986 , by the following vote: AYES: Supervisors Fanden, Schroder, McPeak, Torlakson NOES: None ABSENT: Supervisor Powers ABSTAIN: None -------------------------------------------------------------------- SUBJECT: Concord Naval Weapons Station, Concerns re Possible Contamination The Board received a report dated June 18, 1986 from Dan Bergman, Assistant Health Services Director, Environmental Health, regarding the possibility of contamination of the Contra Costa Canal from Concord Naval Weapons Station hazardous wastes (copy attached hereto and by reference incorporated herein) . Board members expressed concern about the continuing pre- sence of hazardous wastes at the Naval Weapons Station. IT IS BY THE BOARD ORDERED that receipt of the attached report is ACKNOWLEDGED. IT IS FURTHER ORDERED that the Chair is AUTHORIZED to send a letter to the State Environmental Health Services expressing the Boards concerns about the continuing presence of hazardous wastes at the Concord Naval Weapons Station and the need for effective mitigation and ultimate clean-up of this hazardous waste site. ec : Health Services Director Environmental Health Supervisor Powers County Administrator 1 hereby asrtify that this Is a true and correct copy of an action taken and entered on the minutes of the Board of Supero on the date shown. ATTESTED: �g y gL98G PHIL BA HELOR,Clerk of the Board of Supervisors and County Administrator Deputy CONTRA COSTA COUNTY _ HEALTH SERVICES DEPARTMENT ':J 2 1986 - To: Board of Supervisors June 18, 1986 via Phil Batchelor Date: County Administrato From: ,...�'_� Subject: Mark Finucane� Concerns Regarding Possible Health Services 7alth ctor Contamination of Contra by Dan Bergman Costa Canal from Concord Assistant H Ser4ices Director Naval Weapons Station Environmental Health Hazardous Wastes In response to the Board's order of May 20, 1986, the Health Services Department has reviewed the possibility of metals identified at the Concord Naval Weapons Station contaminating the Contra Costa Canal . Such contamination has not occurred to date and future migration of contaminants into the Contra Costa Canal is unlikely based on Environmental Health Division staff's review of the following data and information; o U. S. Army Corps of Engineers January 1986, Site Characterization and February, 1986 Remediation Feasibility Studies. o Direct discussions with State Department of Health Services staff concerning Contra Costa Water District primary and secondary inorganic analysis of water samples taken from the Contra Costa Canal . o Direct discussion with Contra Costa Water District laboratory personnel regarding sampling frequency, location, analytical methods, and historical data concerning inorganic quality of Contra Costa Canal water. Portions of eight parcels, totaling approximately 54 acres, comprise the area of concern at the Concord Naval Weapons Station. The U. S. Government acquired the parcels on behalf of the Navy by Declaration of Taking between 1968 and 1975. The site is located in the old Nichols area on Suisun Bay. A small creek, referred to as Nichols Creek, runs north into the marsh area. The Contra Costa Canal runs 2000 feet to the south of the site. Contamination consists of arsenic, lead, cadmium, selenium, copper and zinc. The contaminants are generally confined to the first six inches of soil, although some patches of metals extend to a depth of eighteen inches in the kiln area. Contra Costa Water District is required by Federal and State Law to sample treated water for inorganic constituents annually. The Contra Costa Water District also samples raw water sources, including .the Contra Costa C.anal , every six weeks. Primary inorganic drinking water contaminants are analyzed for including arsenic, lead, cadmium, and selenium. The water is also analyzed for copper and zinc, which are secondary contaminants. A-41 3181 Board of Supervisors -2- June 18, 1986 Reports are filed with the State Department of Health Services quarterly. No elevated concentrations of arsenic, lead, cadmium, selenium, copper, and zinc have been detected, even in raw canal water to date. Concentrations range from below detection limits to 2ppb; well below maximum contaminant levels acceptable for drinking water. Potential future contamination of canal water from the Concord Naval Weapons site is unlikely for the following reasons: o The tidal property at Concord Naval Weapons Station is downslope from the canal , preventing the transport of contaminated soil into the canal by surface runoff. o Windborne contamination is prevented by grassy vegetation and soil moisture. o The Rock Slough intake is 20 miles up river from the tidal area at Nichols, eliminating the potential for contaminant transport from the near-shore environment to the canal . o When salinity concentrations allow, Contra Costa Water District takes water from Mallard Slough, which is four miles up river from the site. Typically, total metal content in raw water consists mostly of suspended par- ticulate matter. Treated water would be expected to contain only minute con- centrations of metals even if contaminated sediment was to reach the canal , since particulate matter is very efficiently removed during treatment and filtration. The Contra Costa County Department of Health Services, nevertheless, remains concerned about the continuing presence of hazardous wastes identified at the Concord Naval Weapons Station. We are in continuous contact with the State Department of Health Services and the Regional Water Quality Control Board and have reviewed the seven recently proposed remedial action alternatives to assure effective mitigation and ultimate cleanup of this hazardous waste site. MF:DB:rm Ken Axe Wendel Brunner. M.D. Claude Van Marter William Walker, M.D.