During initial environmental studies, the Brookhaven National Laboratory (BNL) site was subdivided geographically into seven Operable Units (OU). Shortly thereafter, two of them were combined to form OU II/VII. The main Operable Units dealing with soil contamination are OU I and OU II/VII. Operable Unit IV also addresses some soil contamination.
The principal soil contaminants in Operable Unit I are radioactive elements, primarily cesium-137 and strontium-90. Elevated levels of heavy metals are also found in some locations. All soil contaminants are confined to BNL property, and access to these areas is controlled as needed to protect employees and the public.
Former Hazardous Waste Management Facility (FHWMF) - The largest volume of contaminated soil was located at the HWMF. It was used from 1947 to 1997 as a central receiving, processing and storage facility for radioactive and hazardous waste generated at BNL. The primary soil contaminants at the FHWMF were cesium-137 and strontium-90. Elevated levels of heavy metals (mercury and lead) were also present in isolated areas.
Cleanup at the FHWMF began during the summer of 2003 with the controlled demolition of several building structures. Workers took down buildings piece-by-piece to minimize dust production and other unnecessary exposure. After the buildings and (if necessary) foundations were removed, approximately 15,000 cubic yards of contaminated soil were excavated from about 13 acres of land. The work was completed in 2005.
Reclamation Facility and Sump Outfall Area - Radioactive elements were found in soils at the reclamation facility and in a sump outfall east of the facility. This facility was used from the late 1950s through the late 1960s to clean radioactive contaminants from clothing and equipment. It is no longer used for decontamination. Water from decontamination of equipment was discharged at the sump outfall area until late 1969. Soils at the sump outfall contain elevated levels of cesium-137 and strontium-90, as well as minor concentrations of other radioactive elements. The contaminated soil was excavated and shipped off site for disposal in 2002.
Upland Recharge/Meadow Marsh Area - This area was used in sewage treatment experiments from 1973 to 1978. Sediments in two of the manmade basins contain elevated levels of heavy metals such as copper, zinc and aluminum. The Meadow Marsh ponds were cleaned up in the summer of 2003 and now function as a habitat for the Tiger Salamander population.
Storm Recharge Basins - These two basins are used to recharge runoff that enters BNL's storm sewer system. Their sediments contain elevated levels of heavy metals such as copper and lead, as well as organic chemicals.
Wooded Wetland - This area is located adjacent to the current landfill and received runoff from that landfill. Sediments here contain elevated levels of metals such as aluminum.
Two Upland Recharge/Meadow Marsh basins were excavated and reconstructed as part of BNL's cleanup program. The storm recharge basins continue to operate and will be monitored. A Tiger Salamander Habitat Management Plan details the routine maintenance required at these basins. BNL conducts annual monitoring of surface water and sediments at the Wooded Wetland.
Both heavy metals and radioactive elements were found in an ash pit, used from 1943 to 1963 to dispose of incinerator ash. Levels of contaminants were typical of those found in incinerator ash. Radioactive elements found here were common in incinerator ash and were unrelated to research operations at BNL. This area was cleaned up in the summer of 2003. The ash pit cleanup involved removing some trees, backfilling soil to even out the grade, placing 12 inches of topsoil to cover the ash, and reseeding the area with native grasses.
A removal action is an accelerated cleanup response to a known contamination source. The following areas of concern in Operable Unit I have been addressed as removal actions:
Former and Interim Landfills - These closed landfills, including a slit trench, were a source of groundwater contamination from volatile organic compounds (VOCs) and strontium-90. The landfills, which cover nine acres of land, were used from 1947 to 1966 for the disposal of general waste, construction debris and chemicals. These landfills have been capped. See the landfill annual reports for more information.
Current Landfill - This closed eight-acre landfill was a source of VOC and tritium groundwater contamination. It was used from 1967 to 1990 for the disposal of the same materials as the other two landfills. The current landfill is no longer in operation for waste disposal and has been capped. See the landfill annual reports for more information.
Chemical Holes - These 55 waste pits were a source of VOC and strontium-90 groundwater contamination. They were used from the late 1950s to 1981 for the disposal of biological waste, chemical containers and glassware. These holes were excavated in 1997. Soil and debris were packaged and shipped off site for disposal in 2005.
Groundwater - VOCs from the current landfill and the HWMF have migrated into the groundwater. Rainwater percolating through contaminated soil can pick up the VOCs and transport them into the groundwater. An air stripping system began operating in December 1996 to treat this groundwater. It has treated over 2.8 billion gallons of groundwater, and has removed over 300 pounds of VOCs.
Cesium-137 and strontium-90 contamination was found in soils here. This facility has been used since 1949 for reducing the volume of liquid radioactive waste prior to disposal. It is still an operational facility. Three large storage tanks were in use here from 1949 to 1987, and were removed in 1994. Six underground tanks and piping, along with radiologically contaminated soils, were removed as part of BNL's environmental cleanup in 2005.
Low levels of cesium-137 were found in soils near several buildings in the center of the BNL site. Soils from the HWMF were used as landscaping and fill material at these locations. These soils were excavated in 2000 and the soil sent for off-site disposal. The excavated areas were backfilled with clean soil and were reseeded.
Two other areas at BNL were examined for radiological contamination. The Alternating Gradient Synchrotron (AGS) storage yards hold steel and equipment that is being stored for potential reuse at the AGS. The former Low Mass Criticality Facility was used for research from the mid-1950s to the mid-1960s, and for temporary drum storage from June 1983 to March 1984. No contamination at levels of human health concern was found at these two locations. No cleanup of these areas is required. Institutional controls and monitoring will continue.
This facility supplies heating and cooling to all major BNL buildings and includes aboveground fuel tanks connected to a boiler building (Building 610) by aboveground and underground pipes. In the past, the Central Steam Facility included underground fuel storage tanks.
In November 1977, a spill of about 25,000 gallons of a waste oil/solvent mixture occurred. The spill pooled on about 1.2 acres and was contained with sand berms. At that time, portable pumps were used to clean up as much as possible. They recovered an unknown quantity of the oil and solvent.
A 5,000-gallon underground storage tank, associated piping and visibly contaminated soil were removed from this area in October 1993. To address the volatile and semi-volatile contaminants remaining in soils and groundwater, an air sparging/soil vapor extraction system was installed. It became operational in November 1997. This system strips volatile and some semi-volatile contaminants from soils and groundwater into their vapor phase. The vapors are then extracted from the ground and filtered to remove the contaminants. To date, this system has removed approximately 35 pounds of chemicals from the spill area. Monitoring showed that, as of late 2000, levels of VOCs in area groundwater were below the drinking water standard. As a result, the system was shut down in January 2001 and dismantled in 2003. Groundwater monitoring will continue. The five-year review of the Operable Unit IV treatment system is available.
Operable Unit V is an area in the eastern-central portion of BNL. This area includes the Lab's sewage treatment plant, an active facility used to process sewage from the Lab's facilities. OU V also includes areas of the Peconic River impacted by past Laboratory operations, as well as sewer pipes and groundwater beneath the eastern portion of the Lab and offsite.
The Peconic River receives discharges from the Lab's sewage treatment plant. During the remedial investigation, elevated levels of heavy metals (such as mercury, copper, and silver), organic chemicals (such as polychlorinated biphenyls, or PCBs), and low levels of pesticides (such as DDD, a product of DDT degradation) and radionuclides were detected in Peconic River sediment.
A cleanup of the river was initiated in May 2004 and completed in May of 2005. Approximately 14,025 linear feet (2.66 miles) of the Peconic River were remediated between the BNL Sewage Treatment Plant (STP) and just downstream of Manor Road in Manorville, NY encompassing a riverbed area of approximately 19.8 acres.
During January 2011 the Peconic River Sediment Trap, located adjacent to Z path and upstream of stream gauging station HQ, was removed as required by the Peconic River ROD. Between November 2010 and January 2011 supplemental sediment was also removed from the PR-WC-06, Sediment Trap, and PR-SS-15.
See the annual monitoring reports for more information.
The Laboratory's sewage treatment plant (STP) processes up to 1.25 million gallons of wastewater per day. Treated effluent is discharged into the Peconic River, north of the treatment facility. The main areas of concern within the STP were the sand filter beds and berms. There are eight sand filter beds, each covering about one acre and containing three feet of sand on top of gravel and tile collection pipes. Wastewater is sent through the sand beds for filtering prior to release.
Some sanitary sewer lines at the Lab were installed as early as 1917, when the property was in use by the U.S. Army for Camp Upton. These old lines were repaired and upgraded by the Army in 1942. The Army constructed them from various materials, including vitrified clay, cast iron and reinforced concrete.
In 1987, BNL investigated these lines and discovered that they were leaking. The Laboratory replaced the sewer pipes leading to the sewage treatment plant with a new line in January 1993. The old pipes were capped and left in place.
The remedial actions for these areas included the excavation and disposal of radiological and mercury-contaminated soils to meet prescribed cleanup goals, and the removal and disposal of radiological contaminated sludge from the ten manholes along the retired sewer lines.
Low levels of volatile organic compounds (VOCs), primarily trichloroethene, were detected in the groundwater of OU V. These VOCs are found at the site boundary east of the Lab's sewage treatment plant and beyond the Lab's eastern boundary. The highest total VOC concentrations currently observed in the plume are less than 20 parts per billion (ppb).
The elevated levels of VOCs originated from discontinued past disposal practices that resulted in releases of VOCs to the Lab's sewage treatment plant. Investigations of soil and groundwater at the sewage treatment plant indicate that there are no continuing sources of VOC contamination.
The elevated levels of VOCs in groundwater off Laboratory property are found at depths (200 feet) below the depths of most residential wells. Homes and businesses in the OU V area were offered public water hookups in 1997 to protect against possible exposure to groundwater contaminants.
No action is proposed for OU V groundwater. VOC concentrations in groundwater are decreasing. Outpost monitoring wells have been placed along the predicted path of the groundwater and additional groundwater monitoring data will be collected. If future monitoring data suggest a need for a groundwater remedy, the OU V remedy will be modified.