Operable Unit V, Peconic River, Record of Decision

January 2005

Operable Unit V, Peconic River, Record of Decision

Peconic River


In 1989, BNL was added to the U.S. Environmental Protection Agency's (EPA) National Priorities List under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, more commonly known as the Superfund Act, as the result of contamination found during a 1988 Department of Energy (DOE) Environmental Survey. Investigators initially identified 28 areas at the Laboratory with some contamination. These areas became known as Areas of Concern (AOCs) and included Solid Waste Management Units (SWMUs) that had been identified earlier by the NYSDEC under the Resource Conservation and Recovery Act (RCRA) permitting process. Cleanup operations at the Laboratory were geographically subdivided into seven Operable Units (OUs) to focus efforts and assign priorities. Later, OU II and OU VII were combined into one OU and additional OUs and AOCs were identified and included in the cleanup.

Operable Unit V Peconic River

Operable Unit V is located in the northeastern quadrant of the BNL property along the eastern property border. This OU was created to originally address contamination from the operation of BNLs Sewage Treatment Plan (STP) that was found in soil and groundwater and Peconic River sediments. The contaminants identified in Peconic River sediments included heavy metals such as mercury and silver, and PCBs. The radionuclides found included americium-241, csium-137, and plutonium-239/240. The level of plutonium found was similar to that expected to be found due to fallout that occurred in the 1950s and 60s.

Remediation of Peconic River sediments (AOC 30) was deferred during the review of the Proposed Remedial Action Plan for the OU in 2000 to allow for evaluation of additional cleanup technologies. Alternative technologies (electrochemical, phytoremediation, vacuum dredging, and wetlands excavation and reconstruction) were identified by stakeholders. Pilot studies were conducted on excavation, vacuum dredging, phytoremediation, and wetlands construction. The original technology excavation proved to be the most effective. In all 19.8 acres of river corridor were cleaned up in 2004/2005.

The OU V remedial action objectives were developed based on the evaluation of the nature and extent of contamination in soils, groundwater, surface water and sediment and the assessment of chemical and radiological risks associated with exposure to contaminants of potential concern. They are meant to reduce site-related contaminants (mercury) in sediment to levels protective of human health; reduce or mitigate, to the extent practicable, existing and potential adverse ecological effects of contaminants in the Peconic River; prevent or reduce to the extent practicable, the migration of contaminants off the BNL facility to areas where risk may be unacceptable.

The cleanup goals established for mercury were to be less than 1 ppm after remediation of river sediment on the BNL site, with a goal that all mercury concentrations in the remediated areas are less than 2 ppm; the off-site cleanup goal was 0.75 ppm with a goal that all mercury concentrations in the remediated areas are less than 2 ppm.

The following is a press release dated February 15, 2005 outlining the highlights of the OU V Peconic River ROD.

Upton, NY - The U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), and the N.Y. State Department of Environmental Conservation (NYSDEC) have agreed on a cleanup plan for contaminated sediment in sections of the Peconic River on the Brookhaven National Laboratory (BNL) site and extending into Suffolk County parkland. The agreement, reached after extensive regulator and public review and comment, allows the Energy Department to implement the selected remedy. It also marks an important milestone in DOE's plan to complete cleanup of the Laboratory site.

The remedy is detailed in a document called the "Final Operable Unit V Record Of Decision for Area of Concern 30 (Peconic River)." The document is available at the libraries listed below, and on the Brookhaven web site.

The Record of Decision (ROD) presents the selected remedial actions for contaminated sediments extending from BNL's sewage treatment plant to approximately 3.5 miles past the site boundary. The portion of the cleanup on Lab property, completed in September 2004, was conducted under an Action Memorandum finalized following public comment periods in 2003 and 2004. This Action Memorandum is included as Appendix A of the ROD. The portion of the cleanup off Laboratory property, including an estimated 9.1 acres within Suffolk County parkland, began after an access agreement with Suffolk County was finalized and is scheduled to be completed in the spring of 2005. The cleanup of the Peconic River beyond BNL property is being conducted under a separate Action Memorandum. This remedy sets a more stringent cleanup goal than for contaminated sediments on the Laboratory site and is included as Appendix B of the ROD.

The ROD agreement, which is supported by the Suffolk County Department of Health Services (SCDHS) and the New York State Department of Health (NYSDOH), follows extensive public participation activities held by the Department of Energy since 1994. The Department of Energy requested input from the community on the Peconic River investigation and potential cleanup approaches. These activities included dozens of briefings to area civic groups, public and private organizations, and the Laboratory's Community Advisory Council and Brookhaven Executive Round Table; more than a dozen round table and informational sessions with interested community residents; public comment periods on related cleanup documents; and informational mailings to and canvassing of homes in the Operable Unit V area. These events generated comments and concerns that have been made part of the public record. The ROD contains a Responsiveness Summary, which documents public comments on the proposed remedial actions, DOE responses to those comments, and changes made as a result of them.


BNL has operated its sewage treatment plant since the Laboratory was established in 1947. Historical operations and disposal practices resulted in the discharge into the Peconic River of wastewater containing chemical and radiological contaminants, which were then deposited in the sediment. Regulations governing the plant have become more stringent through the years, and BNL has periodically upgraded the plant to comply with changing regulations and increase the removal of pollutants. Wastewater from Laboratory operations is processed and treated at the plant before being discharged into the Peconic River on BNL property, and is currently monitored at the discharge point and at several upstream and downstream locations.

Since 1994, DOE and BNL have conducted a detailed investigation of sediment, fish, plants, and water in on- and off-site portions of the Peconic River. Sampling indicates that there are elevated levels of mercury, polychlorinated biphenyls (PCBs), and other contaminants in sediments on and just downstream of the Laboratory property. Elevated levels of mercury and PCBs have also been detected in fish on the Laboratory property; elevated levels of mercury have been detected in fish off the Laboratory site. The New York State Department of Health has evaluated fish samples and determined that consumption within the State advisory guidelines for freshwater fish is acceptable.

Details of Selected Remedy

Under the selected remedy, six to 12 inches of sediment will be removed from areas where contaminants have been deposited. Sediment would also be removed from areas identified as preferential sources of methylmercury, the form of organic mercury found in the environment that accumulates in fish and human tissue. The selected remedy will protect human health and the environment by removing contaminated sediment and contributing to the reduction of mercury in fish tissue.

The off-site area targeted for cleanup lies within Suffolk County parkland. In order to give the County the greatest flexibility in terms of future use or development of the property, the remedy sets a more stringent cleanup target concentration than that for contaminated sediments on the Laboratory site. The $11.5 million project is expected to result in an estimated 92 percent reduction of mercury and 93 percent removal of PCBs in on- and off-site river sediment. Other co-located contaminants will also be removed.

The selected remedy also includes habitat restoration and long-term monitoring of surface water, sediment, and fish to evaluate cleanup effectiveness.

The cleanup will be accomplished using low-impact, conventional construction equipment. Excavated sediment will be shipped off site to a licensed disposal facility, river habitat will be restored as appropriate, and long-term monitoring will verify the effectiveness of the cleanup. The cleanup is proceeding under the guidance of DOE, EPA, and NYSDEC.

Based on the public comments received and subsequent discussions with the EPA, NYSDEC, NYSDOH, and SCDHS, two principal changes were made to the Peconic River wetland restoration process and are reflected in the Record of Decision:

To the maximum extent possible, BNL will not bring in topsoil to replace removed sediment. Instead, sediment will be taken from designated "open water" areas of the river to complete the restoration process following confirmatory sampling.

To the maximum extent possible, wetland plants used to restore sections of the Peconic River will be obtained from within the Peconic River itself.

A map showing the areas where sediment removal is planned, under way, or completed can be found on the BNL web site.

The Final Operable Unit V Record of Decision for Area of Concern 30 (Peconic River) is available at the Mastics-Moriches-Shirley public library, at the BNL library, and at the U.S. Environmental Protection Agency, Region II library in New York City. For further information, call John Carter, U.S. Department of Energy, at 631 344-5195, or Jen Clodius, Brookhaven National Laboratory, at 631 344-2489, or visit the website.

Environmental remediation at Brookhaven Lab is carried out under requirements of the federal Comprehensive Environmental Response, Compensation, and Liability Act of 1980. Past operations at the laboratory have resulted in soil and groundwater contamination. Remediation work is conducted under the framework of an Interagency Agreement among the U.S. Department of Energy, the U.S. Environmental Protection Agency and N.Y. State Department of Environmental Conservation. The Department of Energy owns the Brookhaven property, and oversees and funds the cleanup program.

Community Input

There were numerous opportunities for the community to participate in the decision-making process for the OU V clean-up. In accordance with CERCLA, a Community Relations Plan had been finalized in September 1991, and the Lab established Administrative Record repositories to hold cleanup documents in local libraries. The Community Relations program focused on public information and involvement. A variety of activities including direct mailings, community meetings, poster sessions, tours, workshops, and public meetings were held on the cleanup actions.

As with other Operable Units, a Removal Action, which sought to remove the contamination source as quickly as feasible in order to eliminate any potential threat to the public or environment, was completed prior to the finalization of the OU V ROD. The Action consisted of the removal of the two World War II-era waste settling tanks in 1995; the Imhoff tanks, at the Sewage Treatment Plant. More than 64,000 gallons of sludge was shipped to an off-site waste disposal site. The concrete structure was demolished in 1997 and the area was backfilled with clean soil.

A chronological list of outreach for Operable Unit V may be found in the Responsiveness Summary of the Record of Decision (ROD). Outreach began in 1994 with the release of the OU V Remedial Investigation / Feasibility Study Work Plans. Additional highlights of BNL's outreach included briefings to 13 local civic organizations in 1995, briefings to regulators and elected officials in 1997, a second round of briefings and five roundtable sessions held in 1998 after low levels of plutonium were found in river sediment. Articles updated stakeholders, the Community Advisory Council (CAC), and the Brookhaven Executive Roundtable during 1999 (in fact, as of this writing some 58 presentations have been made to the CAC on the Peconic River). The OU V proposed cleanup plan was released to the public in February 2000. Several hundred written comments were received. As the result of the comments, action to cleanup the river was deferred until further evaluation of less-invasive cleanup technologies took place. In June 2000, a letter summarizing the path forward (announcing additional research into cleanup alternatives for the Peconic River) was mailed to 2,500 stakeholders.

A Peconic Work Group was established and pilot tests were conducted on several alternative cleanup methods over the next year. The CAC also created a Peconic River subcommittee. After the results of the pilot studies were analyzed, a cleanup plan was developed. A public comment period was held on a non-time-critical Removal Action (for removal of sediment on the BNL site) from September 22, 2003 through October 21, 2003. Information sessions were held on October 7 and 15, 2003. A public comment period on the Feasibility Study Addendum and Proposed Remedial Action Plan ran from May 24 through June 25, 2004. Two information sessions, one off site and one on, and a public meeting were held. The Peconic River ROD was signed on January 24, 2005 and removal of the Peconic sediments was completed later that year.

Documents / Links

OU V RI/RA Summary

OU V 1999 Fact Sheet

OU V Peconic River Record of Decision

Additional OU V Documents