DEWEY LOEFFEL LANDFILL
NASSAU, NY
Cleanup Activities
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Background
The Dewey Loeffel Landfill Superfund site is in Rensselaer County, New York. The Loeffel Waste Oil Removal and Service Company operated at the site in the 1950’s and 1960’s. The site was used as a dump for hazardous waste generated by several companies including General Electric (GE), Bendix Corporation (now Honeywell) and Schenectady Chemicals (now SI Group). During that time, the New York State Department of Environmental Conservation (NYSDEC) estimates that more than 46,000 tons of solvents, waste oils, polychlorinated biphenyls (PCBs), scrap materials, sludges and solids were disposed of at the site.
The approximately 19-acre waste disposal area lies within a low area between two wooded hills about four miles northeast of the village of Nassau. The waste materials were dumped into a lagoon area, oil pit and a drum burial area, which are within the present-day landfill. The Dewey Loeffel Landfill site includes the landfill and the groundwater, soil, sediment and surface water bodies that have become contaminated by pollutants from the site.
The state of New York ordered the operator in 1968 to stop discharges from the facility and perform cleanup work following complaints from the community, documented fish and cattle kills and uncontrolled fires at the site.
NYSDEC and entities deemed responsible for the contamination known as potentially responsible parties (PRPs) performed numerous investigations and cleanup actions under the NYSDEC’s Superfund program from 1980 until EPA added the site to the federal Superfund National Priorities List (NPL) in March 2011. These activities included installing a clay cap and a soil/bentonite clay slurry wall at the landfill to limit the migration of contaminants from the landfill, removing drums and storage tanks, monitoring and maintaining residential well treatment systems and removing and disposing of contaminated sediment off site. The PRPs also installed and operated a bedrock groundwater recovery well system which was used to collect contaminated groundwater and leachate that was subsequently shipped off-site via truck. Since 2013, groundwater has been collected and treated onsite using a water treatment plant designed to address contaminants such as VOCs, PCBs and 1,4-dioxane from the groundwater before it is discharged into a nearby stream.
Hazardous substances, including volatile organic compounds (VOCs) and polychlorinated biphenyls (PCBs), migrated from the facility to aquifers and downstream surface water bodies impacting groundwater, surface water, sediment and fish tissue.
There are currently New York State Department of Health fish consumption advisories for Nassau Lake, the Valatie Kill and Kinderhook Lake. EPA is continuing to investigate the site to determine the nature and extent of the contamination and inform the development of permanent cleanup options for the site.What Has Been Done to Clean Up the Site?
EPA collected sediment samples from water bodies downstream from the Dewey Loeffel Landfill in 2009. The results showed the continuing presence of PCBs.
The state of New York referred the site to EPA and issued a letter of support for placing this site on the NPL. EPA added the Dewey Loeffel Landfill site to the NPL in March 2011. Shortly after adding the site to the NPL, EPA began gathering landfill and groundwater data as part of an initial site investigation.
EPA reached an agreement in 2012 with two of the parties responsible for the contamination, General Electric (GE) and SI Group, requiring them to construct and operate a water treatment plant at the site and install five additional groundwater extraction wells along the western edge of the landfill. GE and SI Group constructed the water treatment plant, and it began operating in late 2013. The five additional extraction wells began operating in 2015.
The new extraction wells collect additional contaminated groundwater for treatment at the plant and are closer to the landfill than the three pre-existing extraction wells. A specialized treatment system was added to the treatment plant in 2014 to further address 1,4-dioxane. Regular sampling of the treated water continues. Results show that the plant continues to work effectively and is in compliance with discharge limits established by the state of New York.
The first step in the long-term cleanup of a site is called the Remedial Investigation/Feasibility Study (RI/FS) which helps EPA to determine the nature and extent of contamination, identify potential threats, and evaluate options for cleaning up a site.
EPA finalized an agreement in September 2013 which requires GE and SI Group to perform an RI/FS for the landfill and groundwater components of the site. EPA and GE finalized an agreement in October 2013 requiring GE to perform the RI/FS for the drainageways (surface water bodies) component of the site.
EPA reached an agreement with GE in September 2017 to address PCB-contaminated soil and sediment in Little Thunder Brook (formerly Tributary T11A) and several other upstream waterbodies closer to the landfill. Little Thunder Brook is a small stream located near the landfill that flows into the Valatie Kill. GE completed the work in the upstream waterbodies and in a portion of Little Thunder Brook in 2018 and 2019. After identifying more extensive contamination in Little Thunder Brook, EPA and GE reached an agreement in 2020 requiring GE to perform a remedial investigation to determine the extent of contamination and a study to determine feasible cleanup options, called a Remedial Investigation/Feasibility Study (RI/FS) for Little Thunder Brook. GE will maintain controls, such as stone dams, in Little Thunder Brook during the RI/FS to limit the potential transport of sediment downstream.
Together, the agreements for the landfill and groundwater, drainageways and Little Thunder Brook will result in a comprehensive RI/FS for the entire site. EPA oversees all work performed by GE and/or SI Group under the legal agreements for the site.
What Is the Current Site Status?
EPA is overseeing three separate investigations of the landfill/groundwater, the drainageways and Little Thunder Brook. The investigation of the “drainageways” includes the ponds, streams and other water bodies impacted by the site, including Nassau Lake. The purpose of these investigations, referred to as Remedial Investigations/Feasibility Studies, or RI/FS for short, is to determine the nature and extent of contamination, assess the potential risks to human health and the environment and evaluate potential cleanup alternatives.
GE and EPA finalized the RI/FS work plans for the landfill/groundwater investigation and for the first phase of the drainageways investigation in 2015. Since then, extensive sampling and investigations have been conducted for groundwater, soil, surface water and sediment.
The RI/FS for Little Thunder Brook is underway. Field work began in 2021 and is expected to continue into later 2023.
All of the information gathered from the investigations will be compiled and presented in three reports, called Remedial Investigation Reports (RI Reports) - one for the landfill and groundwater, one for the drainageways, and one for Little Thunder Brook. An RI Report is an in-depth and comprehensive document that contains all data collected to define the nature and extent of contamination at a Superfund site. The data collected and analyzed during each investigation will be used to develop different cleanup alternatives to reduce potential exposure risks to human health and wildlife.
The responsible parties continue to operate a water treatment plant at the site under EPA’s oversight. Regular sampling of the treated water shows that the plant continues to work effectively and is in compliance with discharge limits established by the state of New York.
Sampling data is available on the EPA’s Dewey Loeffel Landfill Superfund site webpage. The treatment plant may be modified in the future based on the final cleanup plan chosen.