Darling Hill Dump is a former 3.5-acre disposal site in rural Lyndon, Vermont. It accepted municipal and industrial waste from 1952 to 1989, including metal plating rinse waters, alkali degreasers, and organic solvents. EPA proposed the site for its National Priorities List (NPL) in June 1988 and formally listed it in October 1989. The NPL is the federal list of sites that may need long-term cleanup under the Superfund program.
Investigators found contamination in both soil and groundwater. Groundwater contains chemicals including benzene, tetrachloroethene, toluene, chromium, and 1,2-dichloroethene. Soil contains heavy metals such as arsenic, cadmium, chromium, and mercury, along with polychlorinated biphenyls (PCBs), pesticides like DDT, and several polycyclic aromatic hydrocarbons (PAHs), which are organic compounds produced by incomplete burning.
The contamination levels found in groundwater were low. Potentially responsible parties installed a carbon filtration system on the public water supply to keep drinking water within federal standards. The village of Lyndonville now operates and monitors that system. EPA completed its remedial investigation and feasibility study in June 1992 and selected a remedy of no-action monitoring for the entire site, meaning ongoing monitoring rather than active cleanup. Construction of that remedy was also completed in June 1992. EPA determined human exposure is under control and that contaminated groundwater has stabilized in its original area. The site was deleted from the NPL in September 1999 and was confirmed ready for anticipated reuse in September 2007.
More recently, Vermont's Department of Environmental Conservation (DEC) began assessing groundwater at and around the site after PFAS (per- and polyfluoroalkyl substances, a group of emerging contaminants) were detected in the public supply well. That assessment is ongoing to determine whether Darling Hill Dump is a likely source of those PFAS. No institutional controls are required at this site because no contamination remains that could cause unacceptable exposure and no remedy components are present that site activity could damage.
Community members with questions can contact the EPA staff assigned to the site. Public records can be reviewed at Lyndonville Town Hall at 119 Park Avenue or at the EPA Region 1 records center in Boston. Additional information is posted at www.epa.gov/superfund/darlinghill.
