(Distributed July 2000)
Tuesday, August 8, 2000
July 24 - August 24, 2000
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Dear Community Member,
The U.S. Department of Energy and Brookhaven National Laboratory are continuing to clean up groundwater contamination from past Lab activities. As part of this effort, we want your comments on a proposal to clean up groundwater in the western Manorville area near Weeks Avenue and North Street.
In late 1996, the Department released a "focused feasibility study" and "proposed plan" for this project. The proposed plan recommended public water hookups and natural attenuation to address this localized area of chemically contaminated groundwater. After collecting and evaluating several years of additional groundwater monitoring data and considering comments from the community and regulators, the Department now proposes the installation of a groundwater treatment unit to clean up this area of chemical contamination.
The Department is holding a 30-day public comment period beginning on July 24. An information session will be held at 7:00 p.m. on Tuesday, August 8, 2000 in the Manorville Fire House to offer you an opportunity to learn more about this proposal and to provide your comments. We invite you to attend this meeting. Also, we encourage you to read this summary sheet. It discusses the background of this cleanup project and the reasons for the new proposal. Written comments on this proposal should be sent to the address at right.
Thank you for your continued interest in the Laboratory's environmental cleanup program and protecting our groundwater resources.
John J. Meersman, Manager
Environmental Restoration Division
Brookhaven National Laboratory
The U.S. Department of Energy proposes to clean up groundwater in the North Street vicinity of Manorville to remove the chemical ethylene dibromide (EDB). This remedy is one of four alternatives examined in 1996 in the Operable Unit VI Focused Feasibility Study. It is now being recommended after collecting and reviewing several years of additional groundwater monitoring data. The Department is seeking public comments on this proposal.
|Groundwater located in an undeveloped area of Manorville contains the chemical ethylene dibromide (EDB) at depths of 90-130 feet below ground. November 1999 EDB monitoring well measurements are shown in parts per billion (ppb).|
What is EDB?
Ethylene dibromide (EDB) was once commonly used as a pesticide and gasoline additive. Laboratory interviews with employees show that EDB was applied to soils on Lab property (Biology Fields on the map above) in the early 1970s to sterilize them prior to experiments. This chemical then leached into groundwater and traveled south with it. The EDB source no longer exists.
In 1992, the Laboratory and Suffolk County found EDB in a localized area of groundwater just southeast of the Laboratory's boundary in an undeveloped area of Manorville. This area of contamination, which the Laboratory has routinely monitored, is located about 1,000 feet west of Weeks Avenue (see map above) at depths of 90-130 feet below ground. In 1998, the Laboratory measured EDB levels of 6.0 parts per billion (ppb). The latest measurements from 1999 are shown above. The federal and state drinking water standard is 0.05 ppb.
What actions have already been taken?
In late 1996, the U.S. Department of Energy and the Laboratory proposed a remedy including public water hookups for residents and businesses in the Weeks Avenue/North Street area. This remedy also called for continuing to monitor EDB levels while allowing them to decrease through natural attenuation (dilution, dispersion and chemical breakdown). Monitoring data would be used to determine if further cleanup action was necessary. Several information sessions and a public meeting were held in the fall of 1996 to gather public comments.
Although a formal agreement with regulators was not finalized, the Department began offering free public water hookups in 1996. This offer was made as a precautionary measure to prevent any possible exposure to EDB in drinking water. Hookups were also offered to several hundred homes south of the Lab as part of the Operable Unit III project (see map below). These hookups were completed in 1998.
|The Department of Energy offered public water hookups to homes in the area shown above as a precautionary measure to prevent any possible exposure to chemicals in the groundwater.|
Why is groundwater treatment being proposed?
As committed to by the Department and the Laboratory in 1996, monitoring of EDB levels in this undeveloped area of Manorville has continued. This monitoring effort has included the installation of additional monitoring wells, as well as computer projections of future EDB movement in the aquifer.
The data collected to date indicate that EDB levels are not lessening as quickly as expected, and groundwater treatment is necessary. Therefore, the Department is working with the U.S. Environmental Protection Agency and the N.Y. State Department of Environmental Conservation in proposing a groundwater treatment unit to remove the EDB from the groundwater. Plans call for a single unit located in an undeveloped area of Manorville near North Street.
This unit will extract the groundwater from the aquifer, send it through carbon filters to remove the EDB, and re-inject the clean water into the ground. Treatment will ensure that cleanup goals are reached and that public health and the environment continue to be protected.
The Department is requesting written comments on this proposed remedy during a public comment period extending from July 24 to August 24, 2000. Comments can be sent to the address on page 1.
Will groundwater treatment be effective?
Yes. The recent re-evaluation of groundwater treatment indicates that this option will best meet the cleanup objectives. These objectives include meeting the drinking water standard for EDB, completing the cleanup in a timely manner, and preventing or minimizing further migration of contaminants.
Initially, the Department preferred natural attenuation because groundwater treatment was expected to be inefficient at removing such low concentrations. Also, it was uncertain whether the carbon filters would be able to reduce EDB levels to below the drinking water standard.
The re-evaluation drew on real-world knowledge from a treatment system that recently began operating in Massachusetts. This system proved to be more efficient than expected and able to reduce EDB levels to below the drinking water standard.
Treatment will greatly reduce the time needed to clean the aquifer. Projections indicated that active treatment will take about nine years to reach the drinking water standard, versus about 40 years for natural attenuation. In addition, a system redesign substantially reduced the estimated cost of groundwater treatment. This combination of advantages convinced the Department that groundwater treatment would best meet the cleanup objectives.
Has the source of the EDB been removed?
The source of the EDB at the Laboratory was intermittent applications of this pesticide to soils in the early 1970s. The area of EDB-contaminated groundwater extends only a short distance north of the Long Island Expressway. This indicates that there is no continuing source of EDB. Soil in the Biology Fields has tested free of EDB. In 1984, the U.S. Environmental Protection Agency banned most pesticide uses of EDB nationwide.
What cleanup alternatives were examined?
To prevent exposure to EDB contamination, four potential alternatives were identified in the 1996 focused feasibility study:
1) No further action. EDB-contaminated groundwater would be allowed to naturally attenuate over time. Groundwater monitoring both on and off site would ensure that EDB attenuation was taking place. This option is required to be evaluated.
2) Natural Attenuation (with additional monitoring). This alternative allowed for natural attenuation via dilution, dispersion and chemical breakdown. It included installation of additional monitoring wells on and off site, with frequent and ongoing groundwater testing to track the movement of the EDB. This testing would ensure that attenuation was taking place as expected.
3) Public Water Hookups (with additional monitoring). All homes within the vicinity of the potential EDB contamination would be provided with public water hookups. This involves installation of water mains, meters, valves, and supply lines to homes. A groundwater monitoring program would evaluate the migration and progress of the natural attenuation of EDB. As mentioned earlier, these public water hookups were completed in 1998.
4) Groundwater Extraction and Treatment by Carbon Adsorption. EDB-contaminated groundwater would be pumped from the aquifer, treated with carbon filters, and discharged to return to the aquifer. Groundwater monitoring would ensure the effectiveness of the remedy.
The 1996 Operable Unit VI Proposed Plan recommended option 3 - public water hookups with additional monitoring. The Department now recommends option 4.
What is the next step?
Written comments can be sent to the Department (see address on page 1) during the comment period from July 24 to August 24, 2000. If accepted by the community, the proposal to treat the groundwater will be reflected in the final Operable Unit VI Record of Decision (ROD). The Department expects to issue this decision later this year. This report will include the Department's responses to all comments received during the 1996 and 2000 public comment periods.
After the ROD is completed, the design and installation of the groundwater treatment unit begins. The Laboratory will continue groundwater monitoring in order to evaluate the effectiveness of the treatment unit and the continued appropriateness of the selected remedy.
Operable Unit VI is an administrative name originally given to an area located in the south/southeastern portion of Brookhaven National Laboratory. This area has historically been used for agricultural experiments and sewage treatment tests. It now includes the area of groundwater containing EDB that extends southeast of the Laboratory.
The Laboratory is a U.S. Department of Energy facility that in 1980 was placed on the New York State Department of Environmental Conservation's "Inactive Hazardous Waste Disposal Sites" list. In 1989, The Lab was included on the U.S. Environmental Protection Agency's "National Priorities List" for cleanup. The Laboratory was placed on these lists because of the environmental effects of past practices, some of which could pose a threat to Long Island's sole source aquifer.
The cleanup of Brookhaven National Laboratory is funded by the U.S. Department of Energy and overseen by the U.S. Environmental Protection Agency and the N.Y. State Department of Environmental Conservation, under what is known as the Interagency Agreement.