The Kenilworth Park Landfill Site (Site) is located within Anacostia Park, a unit of National Capital Parks – East (NACE), on the eastern bank of the Anacostia River. The Site is divided into two areas, Kenilworth Park North (KPN) and Kenilworth Park South (KPS). The areas are separated by Watts Branch, a stream that flows into the Anacostia River.
From 1942 until 1970, the District of Columbia (DC) used the Site for municipal solid waste disposal. Municipal waste incineration, incinerator ash disposal, and landfilling of municipal solid waste occurred at the Site. By the 1970s, the entire landfill (KPN and KPS) had ceased operations, was covered with soil, revegetated, and reclaimed for recreational purposes. KPN currently contains athletic fields which are actively used for recreation. KPS is currently undeveloped and not used for active recreation.
In late 1998, NPS began conducting environmental investigations pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) to determine what risks, if any, the former landfills may pose to human health or the environment.
Under CERCLA, remedial investigations (RIs) are conducted to determine the nature and extent of contamination at a Site and to determine whether any contamination found poses risks to human or ecological health. Based on results of the RIs completed at the Site, NPS identified polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), lead, and methane gas as contaminants of concern at the Site.
Under CERCLA, the RI process is followed by a “feasibility study” or FS. Feasibility studies take the information collected during the RI and evaluations of risk posed by the Site and develop, consider, and evaluate a range of cleanup alternatives, including a “no action” alternative.
NPS completed an initial FS for the Site in April 2012 and in 2013 released a “Proposed Plan” for cleaning up the Site. The Proposed Plan included placement of a 24-inch thick soil cap over both the north and south landfill areas. After receiving public comments and determination that additional groundwater sampling was required to fully evaluate the Site’s impact on underlying groundwater and surface water, NPS decided to defer implementation of the Proposed Plan until the results of additional investigations could be considered.
From 2013 through 2018, NPS conducted additional sampling investigations at the Site. The results of these investigations are summarized in a RI addendum (2019). The RI addendum includes an updated risk analysis that considers future Site uses. In September 2010, an FS addendum was also completed for the Site that provides an updated evaluation of alternatives to cleanup the Site.
Using the assessments completed for the Remedial Investigation, NPS identified and evaluated five cleanup alternatives for the Site. These evaluations are presented in the Feasibility Study Addendum Report which NPS completed in September 2020.
Based on the evaluation completed in the September 2020 Feasibility Study Addendum Report, NPS chose Alternative 3 as the preferred alternative for the Site. On November 12, 2020, NPS released the Proposed cleanup plan for the Kenilworth Park landfill site to explain the preferred alternative and invite public comment on the plan. NPS chose Alternative 3 because it will achieve substantial risk reduction focused on areas of the Site with greatest potential exposure risks. This alternative will allow the Site to be used as intended for both active and passive recreational uses, while reducing risk sooner and at a lower cost than the other alternatives. In February 2021, NPS prepared and released an interim response to comments that mainly related to the CERCLA preferred alternative chosen and how it is related to wetland restoration activities.