Treatment Reduces Microplastics in Landfill Leachate

“Landfills” range from dump sites to highly engineered landfills. These treated and untreated sites are pathways of microplastics (MPs) to watersheds, particularly through landfill leachate. Treating leachate can capture MPs and prevent them from being released with their effluent. Here, we quantified and characterized MPs in landfill leachate from a landfill in Ontario, Canada at different stages in the treatment process. The two treatment levels we assessed were a physical “pre-treatment” and an oxidative “post-treatment”. We also tested untreated leachate collected from an unlined well of a closed section of the landfill. Untreated landfill leachate had the greatest mean [SD] concentration (67 [35.4] MPs per liter) of MPs with up to 127 MPs per liter. Pretreated leachate contained a mean [SD] of 5 [5.8] MPs per liter and post-treated leachate contained2 [1.2] MPs per liter. Most of the particles were fibers and the most abundant polymers identified were polyethylene terephthalate (polyester), polyvinyl chloride and polypropylene. MP concentrations were significantly lower in treated leachate than in untreated leachate ( p < 0.05). Our results demonstrate that treating leachate can divert MPs from the environment.