Operable Unit VI Record of Decision

March 2001


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 VI

Operable Unit VI is located along BNLs southeastern boundary immediately northeast of Operable Unit I. It is a relatively undeveloped section of the BNL facility (Note: the Long Island Solar Farm was proposed for a portion of this area in 2009) that consists of 340 acres of cultivated fields and forest plots that were used for agricultural research. The Areas of Concern (AOCs) are AOC 8, the Experimental Agricultural Fields (the Biology Fields, the Upland Recharge/Meadow Marsh, and the Gamma Field) and AOC 28, an off-site groundwater contamination plume consisting of the chemical ethylene dibromide (EDB) which was a fumigant that was used on the agricultural fields.

The groundwater cleanup objectives adopted for this OU were the same as those for OU III. They are to meet the drinking water standard in groundwater for EDB, complete the groundwater cleanup in a timely manner, which is 30 years or less for the Upper Glacial Aquifer, and to prevent or minimize the further migration of EDB in groundwater.

Soils in the Upland Recharge/Meadow Marsh area were found to contain elevated levels of metals that posed a potential ecological risk to the Tiger Salamander, an NYS endangered species. Contaminated sediments were removed and the wetland reconstructed as documented in the OU I Record of Decision (ROD).

The following press release was issued by DOE on April 4, 2001.

Department of Energy, EPA and NY State Reach Agreement on Addressing Groundwater Contamination near North Street in Manorville

Upton, NY - The U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), and the New York State Department of Environmental Conservation (NYSDEC) have agreed on a remedy to address groundwater contamination in western Manorville, just south of Brookhaven National Laboratory (BNL). The agreement, reached after extensive regulator and public review and comment, allows DOE and BNL to move forward with design, construction and implementation of the proposed remedy.

The remedy is contained in a document titled the Operable Unit VI Record of Decision. The document is available for review at local libraries and on BNL's web site.

The Record of Decision (ROD) presents the selected remedial action for a localized area of groundwater contamination in an undeveloped section of western Manorville located about 1,000 feet west of Weeks Avenue. Groundwater in this area contains the chemical ethylene dibromide (EDB) at levels historically measured up to 6.0 parts per billion at depths of 90 - 130 feet below the land surface. Levels measured in recent monitoring are in the range of 1.0 to 2.0 parts per billion. The state and federal drinking water standard for EDB is 0.05 parts per billion.

EDB was once commonly used throughout the country as a pesticide and gasoline additive. BNL applied EDB to fields on site in the early 1970s to sterilize them prior to agricultural research. In 1996, DOE offered free public water hookups to residents in the Manorville area to prevent the potential for future exposure to EDB.

The selected remedy for the EDB contamination involves active treatment using a carbon system to clean groundwater. It works by filtering groundwater through carbon to remove the contaminant and returning the clean water to the aquifer.

In 1996, DOE had proposed to carefully monitor the EDB and allow it to naturally degrade and disperse over time. However, after reviewing several years of groundwater monitoring data, receiving additional comments from regulatory agencies, and obtaining data from a similar carbon system operating on Cape Cod, the plan has been changed to use active treatment to speed cleanup of the area.

The next step in the cleanup project involves the detailed planning and design of the remedy, including the number and locations of treatment wells. The construction and installation of this treatment system will then proceed according to the design once approved by DOE, EPA, and NYSDEC.

The ROD agreement follows several public participation activities held by DOE and BNL to obtain input on the Operable Unit VI investigation and potential cleanup approaches. Two information sessions and a public meeting on Operable Unit VI issues were held at the Lab in the fall of 1996, and another information session was held in the summer of 2000. 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 and DOE responses to those comments.

Environmental remediation at BNL is carried out under requirements of the federal Comprehensive Environmental Response, Compensation and Liability Act of 1980, commonly known as the Superfund Law. BNL is on the Superfund list due to past operations that 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 BNL property and oversees and pays for all cleanup costs at the site.

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 Laboratory 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, Removal Actions, which sought to remove the contamination source as quickly as feasible in order to eliminate any potential threat to the public or environment, were completed prior to the finalization of the OU VI ROD. An Action Memorandum was issued in September 1996 for the hookup of area homes to public water.

In August 1996, area homes were canvassed door-to-door and elected officials were briefed. A Focused Feasibility Study and a Proposed Remedial Action Plan were distributed to the BNL mailing list in August 1996 and November 1996. Several press releases were issued and applications for public water hookup were mailed to residents. A 60-day public comment period on the Feasibility Study and Proposed Remedial Action Plan began October 3 and ran through December 6, 1996. Poster sessions were held at the Manorville Fire House and the local Civic Association was briefed. A public meeting was held at the Dayton Avenue School on November 13, 1996. Approximately 120 people were in attendance.

Based on new data from monitoring wells installed after the publication of the PRAP in 1996, the proposed remedy was changed to include active treatment of the EDB groundwater plume. A new fact sheet was mailed to 2,550 residents on the BNL mailing list in 2000. Additional information meetings were held in August 2000, a new public comment period was held, and BNL's Community Advisory Council was provided with a briefing. In addition to extending the public water hookup area to include some homes near Weeks Avenue in Manorville, a groundwater treatment system began operation in 2004 to speed up the cleanup. The ROD was approved by the EPA in March 2001.

Documents / Links

OU VI Record of Decision