Landfill leachate forms when rainwater filters down through wastes piled up in landfills. When it comes into contact with a landfill, this rainwater “leaches” or pulls out chemicals from wastes. The resulting liquid is called leachate, and it can contain a wide range of chemical contaminants that are hazardous to human health.

In the U.S., composite liners, usually made of plastic and set over a layer of compacted clay soil surrounding the bottom and sides of the landfill are required. Liners are meant to protect groundwater and underlying soil from leachate releases—however, landfill liners, including those used on Brookhaven Landfill, commonly leak. What’s more, leachate collection and removal systems are often installed on landfills to remove leachate for treatment and disposal. At the Brookhaven Landfill, leachate is collected and treated on site with hydrogen peroxide in storage tanks (to reduce odors), then pumped and hauled away by tanker trucks to the Suffolk County Southwest Sewer District Wastewater Treatment Plant at Bergen Point—where after treatment, it is pumped into the Atlantic Ocean. In other areas, untreated leachate is commonly pumped into deep injection wells, moving toxic waste elsewhere—most commonly into other underserved communities, spreading pollution and injustice.

Contaminant plumes or concentrated liquid contaminants are commonly caused by landfills and the chemicals they leach. These plumes typically travel through earth in the same direction as groundwater. U.S. Geological Survey scientists detected a contaminant plume in the 1980s spreading from the Brookhaven Landfill, as toxic leachate breached its leaking liner through the region’s shallow Upper Glacial aquifer. North Bellport sits in the plume’s path, and water tests in and around the community have shown detectable, elevated levels of PFAS, iron, BPA, manganese, ammonia and 1,4-Dioxane in ground and surface waters.

Chemicals with the potential to harm the environment and/or human health due to their concentration, distribution, exposure type, and toxicity. Chemicals and contaminants of concern related to the Brookhaven Landfill can pollute air, land, and groundwater, and include:

1,1,1-trichloroethane, 1,1-dichloroethane, 1,2-dichloroethane, 1,4-Dioxane, 1,4-dichlorobenzene, 2-butanone (MEK), 4-methyl-2-pentanone, Acetone, Ammonia, Arsenic , Benzene , Bisphenol A (BPA), Cadmium, Chromium , Chlorobenzene, Chloroethane, Dioxins, Dichlorodifluoromethane, Ethylbenzene, Iron, Lead, Manganese, Mercury, Nickel, Particulate pollution, PCBs, PFAS, Styrene, Tetrachloroethene, Toluene, Trichloroethane, Trichlorotrifluoroethane, Vanadium, Vinyl chloride, Xylenes