Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
Sacramento Army Depot
EPA #: CA0210020780
Congressional District: 05
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Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 10/15/84
Final Date: 07/22/87
The 485-acre Sacramento Army Depot, established in 1945, was a supply depot primarily responsible for the receipt, storage, issuance, maintenance, and disposal of electronics supplies. Wastes from metal-plating operations, spray booth operations, and degreasing operations were discharged to unlined sewage lagoons, burned, or buried on site. These practices resulted in the contamination of some on-site soils at the former Oxidation Lagoons and Burn Pits and other areas, as well as the groundwater beneath the site. Soil contamination also was shown in drainage ditches leading to the Old Morrison Creek. Approximately 50,000 people live within three miles of the site. Morrison Creek flows around the southern boundaries of Sacramento Army Depot. The groundwater contamination at the site is in both the shallow and intermediate water-bearing zones and has migrated off site. The Depot has been closed and property transferred.
Contaminants and Risks
- Soil and Sludges
Groundwater is contaminated with various volatile organic compounds (VOCs). Soils at the former Oxidation Lagoons contain heavy metals including lead, cadmium, and chromium. Surface soils from on-site drainage ditches are contaminated with heavy metals including cadmium. Potential health threats to people include drinking, eating, breathing, or coming into direct contact with contaminated soils or groundwater.
Investigation and Cleanup Activities
This site is being addressed in five long-term remedial phases focusing on cleanup of the entire site, groundwater, Tank 2, the oxidation lagoons, and the burn pits.
Entire Site: The Army investigated the nature and extent of contamination associated with the site. The investigations identified the contaminants and recommended alternatives for final cleanup. Investigations focused on identifying all areas of soil contamination, especially those affecting groundwater. The Army has installed a new extraction system south of Sacramento Army Depot to optimize groundwater treatment. The existing system has been shut down for one year to perform rebound studies.
Groundwater: In 1990, the Army began operating a groundwater treatment facility. Seven groundwater vertical extraction wells pump the water to the treatment plant where hydrogen peroxide is added; the water then passes through a bank of ultraviolet lights to be decontaminated and then discharged into a sanitary sewer. Additional extraction wells (one vertical and two horizontal) have been installed to expand the capture zone and decrease the time necessary to achieve remediation objectives. However, problems were encountered with the performance of the horizontal extraction wells. Due to biofouling of the well screens, the pumping rates of these two horizontal extraction wells decreased rapidly from the time of start up. Attempts to clean the well screens were unsuccessful. The horizontal extraction wells were then shut down. In February 2000, the groundwater treatment units were shut down because the VOC concentrations in the groundwater pumped from the extraction wells met Sacramento County sanitary sewer system discharge requirements. Currently, groundwater is being pumped from the eight extraction wells and discharged directly to the Sacramento Regional Wastewater Treatment Plant. The Army has conducted four five-year reviews. The fourth five-year review was completed in 2012.
Tank 2: A study of the contamination around Tank 2 was completed in 1991. The final cleanup remedy, selected in late 1991, called for soil vapor extraction to remove the VOCs from the soil. All cleanup activities were completed in the summer of 1994. In June 1996, the Army conducted Tank 2 reconfirmation sampling to confirm the previous results, since the data packages the laboratories provided were insufficient to verify the quality of the analyses, and the analyses were not validated using EPA guidelines. The reconfirmation sampling analytical results confirmed the soil contaminated at Tank 2 area has been remediated, and the site is now considered clean.
Oxidation Lagoons: In 1988, the Army began a study of the nature and extent of contamination related to the oxidation lagoons. The final cleanup remedy, selected in the fall of 1992, was soil washing to remove heavy metal contamination. This remedy failed. The new cleanup remedy, solidification of contaminated soil, was selected to remove heavy metal contamination. The solidification of contaminated soil with heavy metal has been completed, and the Army prepared the Final Remediation Report.
Burn Pits: In 1991, the Army began a study of the contamination in and around the burn pits. A remedy was selected in 1993 that divides the cleanup into two phases. The first phase uses soil vapor extraction to remove VOCs from the soil. This cleanup action is now complete. The second phase of cleanup, solidification of contaminated soil with heavy metals, has been completed, and the Army prepared the Final Remediation Report.
The Sacramento Army Depot is participating in the Installation Restoration Program, a specially funded program established by the Department of Defense (DOD) in 1978 to identify, investigate, and control the migration of hazardous contaminants at military and other DOD facilities.
Cleanup Results to Date
The Army has cleaned up the contaminated soil surrounding Tank 2, at the Oxidation Lagoons area, and at the Burn Pits. The operation of the groundwater treatment facility will continue to protect area residents from exposure to contaminated groundwater at the Sacramento Army Depot.
EPA and the state regulations concurred with the 2012 Fourth Five Year Review Report that the remedial actions implemented at this site continued to be protective of human health and the environment.
Potentially Responsible Parties
Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.
Online information about the PRPs for the site is not yet available.
Documents and Reports
Public Information Repositories
The public information repositories for the site are at the following locations:
Sacramento Army Depot,
Visitor Control Building,
8350 Fruitridge Road,
Sacramento, CA 95813
EPA Site Manager
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
8800 Cal Center Drive
Sacramento, CA 95826-3200
After Hours (Emergency Response)