LAWRENCE LIVERMORE NATIONAL LABORATORY: SITE 300
SITE CHARACTERISTICS

Nature and Extent of Contamination

During past operations at the site, contaminants were released to the environment from surface spills and piping leaks, leaching from unlined landfills and pits, high-explosive test detonations, and disposal of waste fluids in lagoons and dry wells (sumps).

Environmental investigations have identified 23 locations where contaminants were released (Figure 2).

The primary contaminants of concern at Site 300 include trichloroethylene (TCE) and other volatile organic compounds (VOCs), high-explosive compounds, perchlorate, nitrate, tritium, uranium, polychlorinated biphenyls, silicone-based oils (tetra-butyl-orthosilicate (TBOS), and metals.

In 1990, the U.S. EPA placed Site 300 on the National Priorities List (Superfund). Since then all investigation and cleanup activities have been conducted under regulations administered by the U.S. EPA and the state of California.

All releases at LLNL Site 300 have been assigned to 1 of 8 operable units (OUs) to more effectively manage the site cleanup.

Each OU includes a source area(s) and associated contaminated soil, bedrock, ground water and surface water. The eight OUs are shown on Figure 3 and described below.

General Services Area (GSA) (OU-1)

Past disposal of degreasing solvents caused VOC contamination in soil, and ground water. Two primary ground water plumes were been identified, both which extended offsite. A Record of Decision for the OU was signed in 1997, and ground water and soil cleanup is underway.

Building 834 (OU-2)

Spills and piping leaks from the early 1960s to the mid-1980s resulted in contamination of the subsurface with VOCs and TBOS. Nitrate in ground water results from septic system effluent but may also have natural sources. The contamination is present in the vadose zone and perched water-bearing unit; the deeper regional aquifer has not been affected. Ground water and vadose zone remediation is ongoing.

Pit 6 Landfill (OU-3)

From 1964 to 1973, approximately 1,900 cubic yards of waste was placed in unlined debris trenches and pits at the Pit 6 Landfill. The waste included laboratory equipment, craft shop debris, and biomedical waste. VOCs, tritium, nitrate, and perchlorate are present in ground water downgradient from the landfill. An engineered cap was placed on the landfill in 1997 to prevent infiltrating rain water from further leaching contaminants from the buried waste.

High Explosives Process Area (OU-4)

Surface spills from 1958 to 1986 resulted in the release of VOCs at the former Building 815 steam plant. High explosive (HE) compounds, nitrate, and perchlorate in the subsurface are attributed to wastewater discharges from the former, unlined rinsewater lagoons from the 1950s to 1985. VOCs were detected in ground water near the former HE Burn Pit that was capped in 1998. Ground water extraction and treatment are under way to prevent TCE in ground water from moving offsite.

Building 850 Firing Table (OU-5)

High explosives experiments have been conducted at the Building 850 Firing Table since 1958. Dispersion of test assembly debris during detonations resulted in PCB, dioxin, furan, and metal contamination in surface soil. Leaching from firing table debris resulted in tritium and depleted uranium in ground water.

Pit 7 Complex (OU-5)

From 1958 to 1988, a large volume of gravel and debris generated by firing table operations were placed in four unlined landfill at the Pit 7 Complex (Pits 3, 4, 5, and 7). VOCs, nitrate, uranium, and tritium have been released to ground water. Pits 4 and 7 were capped in 1994 under the RCRA.

Building 854 (OU-6)

TCE was used as a heat-exchange fluid at the Building 854 Complex between 1967 and 1984 and was released to soil and ground water through leaks from the piping system. Other contaminants in ground water include nitrate and perchlorate. TCE-contaminated soil was excavated near Building 854 F. Two ground water extraction and treatment systems have been installed to remove contaminant mass and prevent plume migration.

Building 832 Canyon (OU-7)

TCE was released to soil and ground water through leaks and discharges of heat-exchange fluid at Buildings 830 and 832 between the late 1950s and 1985. Nitrate and perchlorate are also present in ground water. Soil vapor and ground water extraction and treatment systems have been installed at Buildings 830 and 832 to remove source area contamination. Additional ground water extraction and treatment systems were placed in downgradient portions of the plume to prevent offsite plume migration.

Site 300 Site-Wide OU-8

Operable unit 8 consists of several small releases sites located throughout Site 300. These include Buildings 801 and 833, the Buildings 845 and 851 firing tables, and the Pit 8 and 9 landfills. Contamination in these areas includes low concentrations of VOCs, nitrate, perchlorate, tritium, and uranium. Because the contaminants do not pose a risk to human health or a significant threat to ground water, these areas are monitored to ensure there are no further impacts to human health or the environment.


Next: Site Conditions