Description of Peconic River and Sewage Treatment Plant Projects
During initial environmental studies, the Brookhaven National
Laboratory (BNL) site was subdivided geographically into seven
Operable Units (OU).
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.
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. Most of the
contaminants were found in the top six inches. As expected,
contaminants are more prevalent in areas where more sediment is
deposited by the river and decrease with distance downriver.
In February 2000, the U.S. Department of Energy (DOE) proposed
the excavation of all Peconic River sediment containing contaminant
levels higher than cleanup goals. The excavated sediment would be
dewatered in drying beds and disposed of off site. In response to
public comments, a workshop
was held in December 2000 to further examine remedial alternatives.
A final cleanup plan has not been selected yet.
Sewage Treatment Plant
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.
Discharges from this plant are regulated by the New York State
Department of Environmental Conservation, and are routinely
monitored for compliance. Monitoring results are reported in annual Site
The main areas of concern within the STP are 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.
In the past, the Lab removed some soils from the sand filter beds
after accidental releases of contaminants into the beds occurred.
The contaminated material from the sand filter beds was piled onto
adjacent areas known as sand filter berms. Thus, the soils with
higher levels of contamination are located within these bermed
Soils within the sand filter beds and berms contain elevated
levels of mercury, silver, chromium and lead. Elevated levels of
cesium-137 are found in a few isolated areas, primarily in the sand
filter berms. Soil contamination is concentrated in the top six
DOE and BNL propose that soils at the Lab's sewage treatment
plant containing levels of contaminants above cleanup goals be
excavated and shipped to a licensed off-site disposal facility.
Excavated areas would be backfilled with clean soil and regraded. A
final cleanup plan has not been selected yet.
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.
In 1995, the Laboratory sampled soils surrounding the areas where
leaks were identified along the retired and capped sewer line during
the OU V investigation. The results of the investigation identified
only a few areas with low concentrations of inorganic constituents.
This indicates that the sewer line leading to the STP is not a
source of significant contamination to the surrounding soils. As
part of a more recent investigation, sludge was collected from the
bottom of 10 manholes along the retired and capped sewer line and
analyzed for radionuclides. The results identified elevated
activities of two radionuclides - americium-241 and cesium-137.
The OU V sewer line has been retired and capped at both ends;
therefore, no exposure pathway presently exists. Brookhaven will
remove contaminated sludge from the 10 manholes along the retired
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
level found on site in 2000 was 17.9 parts per billion (ppb). The
maximum off-site level was 10.7 ppb, which is above the drinking
water standard of 5 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