PFAS CONTAMINATION OF STORMWATER FROM LANDFILL LEACHATE SEEPS

In wet climates, uncapped landfills or those with poor daily-cover practices can produce leachate. Worldwide research has shown that municipal solid waste landfill leachate typically contains various per- and polyfluoroalkyl substances (PFAS) compounds, frequently at significant concentrations. As such, landfill leachate discharges are one of the main pathways for PFAS releases into the environment. Landfill leachate “seeps” are unintentional release mechanisms by which leachate discharges openly, along landfill sidewalls, above the subsurface liner. These undesirable malfunctions allow raw leachate and contaminated stormwater to run down and erode the sidewalls of the landfill and find their way into the stormwater ditches along the base of the landfill. The result is surface-water contamination that can move quickly and over long distances, impacting groundwater, soil, streams, ponds, lakes, sediment, biota, and offsite receptors. And the infiltration of leachate from these seeps into the subsurface can be aggravated by the common practice of removing locally protective natural clay layers for landfill construction materials. This presentation discusses a conceptual model for this contaminant transport pathway and tests this model with actual contamination data for a case study example.