Plan for STP and Peconic River Cleanup Released
Operable Unit V is the formal designation for the eastern-central portion of BNL that includes leaking sewer lines (Area of Concern 21) and the Sewage Treatment Plant (STP AOC 4). The STP discharges treated water into the headwaters of the Peconic River. The STP complex includes several processing buildings, a settling tank, six active sand filter beds, and two storage ponds.
The OU V Remedial Investigation, conducted between 1995 and 1997, looked at soil, sediment, surface water, and groundwater. Elevated levels of heavy metals, including mercury and silver, and low levels of radionuclides including cesium-137 were found in the soils at the STP. Downstream of the discharge point, PCBs, radionuclides, and mercury and silver were detected in river sediment. Volatile organic compounds (VOCs) and low levels of tritium were found in the groundwater in the southeastern portion of OU V and in off-site areas east and southeast of BNL. (After determining the groundwater contamination posed no health threat, it was monitored and allowed to naturally degrade and decay under the OU V Record of Decision.)
The OU V Risk Assessment evaluated chemical, ecological, and radiological risks to human health and the environment. During the ecological risk assessment it was determined that fish in the on-site portion of the Peconic River showed a bioaccumulation of PCBs and mercury that could pose a hazard to wildlife preying solely on them. The on-site fish did not pose a threat to human health as the waters are unfishable and the fish were considered too small for human consumption.
In the spring of 1999, an investigation of on-and off-site Peconic River sediments and soils was conducted for plutonium and related radionuclides and to assess the potential risk to human health. The Plutonium Contamination Characterization and Radiological Dose and Risk Assessment Report found that plutonium and other radionuclides were present in the Peconic River; however, the levels were well below those that would affect public health or aquatic life. The areas requiring cleanup were defined by the metals and PCBs. (The results of the plutonium sampling were announced in October 1999 through a press briefing and several information sessions including two held off the BNL site.)
The Feasibility Study (FS) for OU V was released in November, 1999. The FS developed and evaluated cleanup actions for the contaminated soils and sediments from the Peconic River and the STP.
A proposed cleanup plan for the STP and Peconic River was released on February 15, 2000. It described five cleanup alternatives for contaminated Peconic River sediments and evaluated them. The first was to take No Action, the others required excavation, to varying degrees, of river sediments. The plan also included four alternatives for addressing contamination at BNL's STP that called for excavation of the contaminated soils in the sand filter beds and berms and for it to be shipped off-site to a licensed facility.
The first public comment period for Operable Unit V, which was held from May 27, 1998 through July 27, 1998 when the Remedial Investigation / Risk Assessment Report was released for public review and comment, was uneventful. However, the completion of the Feasibility Study and release of a cleanup plan in February 2000, resulted in a tremendous response from the community with dozens attending four public meetings held on the proposed plan.
Roundtable meetings were held on February 23 at BNL and on February 29 at Riverhead High School. Over 30 members of the community attended the meetings. A public meeting attended by 40 people was held on March 2, 2000 at Berkner Hall. After receiving comments that the time allowed for review of the plan was inadequate, the Public Comment Period was extended an additional 60 days. At the close of the comment period, the Laboratory and the Department of Energy (DOE) had received several hundred comments on the proposed plan. One of the primary concerns expressed was the potential impact of sediment removal within the river corridor on wetlands and wildlife.
DOE and BNL determined that the best way to respond to the comments from the community was to move forward with the clean up of the STP and defer cleanup of the Peconic River until the proposed options could be further evaluated. The DOE Site Office sent a letter to stakeholders dated June 2, 2000 announcing that the decision on how to clean up the Peconic River sediments would be deferred. Site Manager George Malosh explained that DOE and BNL had been working closely with the Environmental Protection Agency, the N.Y.S. Department of Environmental Conservation, and the S.C. Department of Health Services to establish procedures to further the cleanup. He said, "DOE would consider alternatives that will not create a disruption of the wetlands and woodlands and that will allow for a more exact determination and delineation of the locations and amounts of sediments that need to be removed. Opportunities for stakeholder input will continue to be provided and he encouraged community participation."
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