After several years of investigation, sampling, community input, remediation plan design and actual cleanup, Brookhaven's environmental restoration program is now rounding the final turn and heading for the home stretch.
The groundwater program has moved from the investigative phase to the design and cleanup phase. The U.S. Department of Energy (DOE) and the Lab are gearing up to turn their full attention to final cleanup activities. Among these are groundwater cleanup actions for the Building 96 area and the tritium plume, and the design and installation of additional groundwater treatment systems.
Building 96
Many years ago, Building 96 was a drum storage area. As with many such sites across the country, attention to this storage area was not as rigorous as it would be today. During past years, chemical spills and leaks probably took place.
Investigations in the area of Building 96 revealed that this was a likely source of chemical groundwater contamination. The chemicals are primarily volatile organic compounds (VOCs) used as solvents in years past. Also, soils in this area contain polychlorinated biphenyls, better known as PCBs.
Groundwater treatment systems, already placed near the Laboratory boundaries to prevent further migration of chemicals off site to assure protection of the public, were given priority. Now Brookhaven is planning to address the source area.
The Laboratory has excavated some of the soils containing PCBs (see photo), and additional excavation is planned to remove all soils with PCBs above regulatory levels.
Additionally, BNL plans to construct a groundwater treatment system to remove the VOCs from this area. Installation of this treatment system, along with others upstream of the existing systems, will eventually allow systems at the Lab boundary to be shut down. When the systems are shut down after several more years of operation, groundwater monitoring will continue. The systems will be restarted if monitoring shows it is necessary.
The system at Building 96 will clean the groundwater within the treatment wells, using air stripping, rather than pumping the water to another location for treatment.
A similar system is already operating in an industrial park south of the Laboratory, and has proven extremely effective in removing VOCs. At Building 96, the wells have already been installed. The treatment facilities will be installed as soon as excavation of the soils containing PCBs is completed.
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| A layer of soil approximately six inches deep, containing high levels of PCBs, was removed from the Building 96 area. Additional excavation is planned. |
Tritium remedy
BNL is also installing groundwater extraction systems to address tritium released from the High Flux Beam Reactor (HFBR). The cleanup plan being agreed to with the regulatory agencies (see article, page 8) calls for extraction wells to be placed very close to the HFBR. The plume from this facility has not reached the Lab boundary and is already well below the drinking water standard at the leading edge. The Lab is installing these wells to assure that higher concentrations of tritium will never reach the site boundary.
The extraction wells will be used to remove the highest levels of tritium contamination with the smallest amount of water possible. Since the HFBR is now permanently shut down and the spent fuel pool, the original source of the tritium, is empty, the tritium source no longer exists. Removing the highest tritium levels will help the plume to continue to dissipate through radioactive decay and natural dispersion.
System designs
Designing groundwater cleanup systems is critical to the success of the cleanup effort. Designers must consider the type of contaminant, available areas to construct a treatment system, location of utilities below the ground surface, the cleanup goal to be achieved, the impact on other treatment systems located nearby and local hydrogeological conditions. Right now, a lot of this design work is underway.
Middle Road - A system is being designed for installation on site at Middle Road (see map, above right) that will remove the VOCs migrating toward the site boundary. Construction of this system is planned for October 2000.
Southwestern Boundary - This system was added to the cleanup remedy as a result of community and regulatory input. The public voiced concern that this part of the plume could reach the Carmans River. While this could occur, levels entering the river would be below drinking water standards and would be immediately diluted to nondetectable levels. However, in response to the public concern, DOE agreed to conduct additional treatment in this area. Construction is planned for 2001.
North Street East - This system will be the second treatment system constructed off the BNL site. Placing a system in this area will prevent further migration of the VOCs located to the north. Construction of this system is also anticipated for 2001.
The goal for the Department of Energy and Brookhaven National Laboratory is to have all of the cleanup systems installed and operating by 2006 or earlier. Currently, DOE and BNL are making a concerted effort to accelerate the cleanup schedule. This is being done with substantial support from the community organizations that have banded together for a common cause cleaning up the Laboratory for good. As Dr. Marburger, Laboratory Director, likes to say we will "Clean it up and keep it clean."
DOE and BNL are committed to working closely with our neighbors to assure sound environmental stewardship by the Laboratory.