The Role of Plastic Debris as Another Source of Hazardous Chemicals in Lower-Trophic Level Organisms

Abstract

Over the last decade, it has become indisputable that small plastic debris contaminates habitats and wildlife globally. Of concern is that this material, which is ingested by hundreds of species across multiple trophic levels, is associated with a complex mixture of hazardous chemicals. Models, laboratory exposures, and field studies have all demonstrated that plastic debris can act as a source for hazardous chemicals to bioaccumulate in animals. This has been demonstrated with several plastic types, including polystyrene, polyvinyl chloride (PVC), polyurethane foam, and polyethylene, and for several different organic chemicals, including PCBs, PAHs, PBDEs, triclosan, and nonylphenol. What remains less certain is the ecological importance of this transfer, i.e., the relative contribution of plastic as a source of chemicals to wildlife relative to other sources. Experimental data suggests that for some chemicals and under certain exposure scenarios, plastic debris may be a relatively important source of chemicals, including at environmentally relevant exposure concentrations. Toxicological studies in the laboratory demonstrate adverse effects from the combination of plastic and hazardous chemicals in fish and lugworms. Further research is warranted to better understand the mechanisms by which plastic-associated contaminants transfer to organisms and if the chemicals are biomagnified in higher trophic level animals leading to ecological consequences or even human health effects via consumption of contaminated seafood.