(Original distribution: March 1, 1999)
What contaminants were found?
The primary contaminants in Operable Unit III are solvents (volatile organic compounds, or VOCs), strontium-90 and tritium. The most common VOC contaminants are carbon tetrachloride, tetrachloroethene and trichloroethane. Other VOC contaminants were also found in lesser amounts.
Where is the groundwater contamination?
Several plumes, or areas, of groundwater contamination have been identified. The plumes of groundwater that contain solvents extend from the middle of the BNL site southward. The leading edge of the longest plume is at Flower Hill Drive (see map on back). As a precautionary measure, public water hookups have been provided to residents immediately south of the Lab.
A tritium plume whose source was the spent fuel pool of the High Flux Beam Reactor (HFBR) has been identified. It is confined to BNL property. Levels of tritium above the drinking water standard are found near the center of BNL and extend to a point about one mile north of the southern boundary of the Lab.
There are concentrated areas of strontium-90 contamination in the groundwater at these on-site locations: the chemical holes area, the Brookhaven Graphite Research Reactor (BGRR) and pile fan sump, and the Waste Concentration Facility (WCF).
What are the cleanup alternatives?
For the VOCs, seven cleanup alternatives were examined in the Feasibility Study. These alternatives included one or more of the following elements: No action (which is required for comparison with other options), construction of on- and off-site groundwater treatment systems, continuing operation of existing groundwater treatment systems, and carrying out an on-site source removal action. The alternatives varied in the elements used, the number and location of treatment systems, and the amount of time it would take to reach cleanup objectives.
Eight alternatives were examined for remediating the tritium plume. These alternatives included one or more of the following elements: No action, natural attenuation, operation of the existing pumping system, placing the existing system in a "standby" mode, installing an extraction system immediately south of the HFBR, and installing additional extraction wells at the leading edge of the plume.
Five alternatives for strontium-90 remediation were examined. These alternatives included one or more of the following elements: No action, natural attenuation, groundwater extraction and treatment, injection of chemicals to precipitate out the strontium, and use of a permeable wall to capture the strontium.
What are the DOE's preferred cleanup methods?
For the VOC plumes, the DOE's preferred alternative is V10b. This will involve the use of on-site and off-site groundwater treatment systems at several locations. Treatment systems would be placed on site, and off site in the Long Island Power Authority right-of-way, in unpopulated areas of North Street and east of North Street, at the Brookhaven Airport, and in the eastern portion of the industrial park located south of BNL. This alternative also includes the continued operation of the existing on- and off-site treatment systems, as well as a source removal action. Natural attenuation and monitoring are included in this alternative.
For the tritium plume, the DOE's preferred alternative is T4 - contingency based remediation. In this alternative, the current pump-and-recharge system will be placed on standby. The tritium levels will decline through a combination of radioactive decay, dilution, and dispersion. Monitoring will continue. The need to restart the existing pump-and-recharge system, and/or to start operating a new system immediately south of the HFBR, will be evaluated if tritium levels diverge substantially from those expected.
For the strontium-90, the DOE's preferred alternative is S5a. This will involve the installation of groundwater extraction/ion exchange treatment systems. These systems will extract the groundwater, treat it by ion exchange to remove the strontium-90, and discharge the clean water to on-site recharge basins.
The public comment period for the Operable Unit III Feasibility Study and Proposed Plan is from March 1 to March 31, 1999. Submit comments in writing during the comment period to:
U.S. Department of Energy
P.O. Box 5000
Upton, N.Y. 11973-5000
For more information, contact:
Brookhaven National Laboratory
U.S. Department of Energy
U.S. Environmental Protection Agency
N.Y. State Dept. of Environmental Conservation
Copies of the Feasibility Study and the Proposed Plan are available for review at:
Longwood Public Library
BNL Research Library
U.S. EPA, Region II Library
This figure shows the locations of groundwater contaminants at levels above drinking water standards. It also indicates proposed locations for treatment systems, as well as the locations of the tritium and strontium-90 sources.