Polymer-Specific Modeling of the Environmental Emissions of Seven Commodity Plastics As Macro- and Microplastics

Plastic has been identified as an emerging contaminant in aquatic and terrestrial ecosystems. Uncertainties remain concerning the amounts present in the environment and the main responsible sources. In this study, the emissions of macro- and microplastics have been mapped for seven polymers in Switzerland. The modeling is based on a complete analysis of the flows from production and use to end-of-life using probabilistic material flow analysis. We estimate that 94 +/- 34 g/capita/year of low-density polyethylene, 98 +/- 50 g/cap/a of high-density polyethylene, 126 +/- 43 g/cap/a of polypropylene, 24 +/- 13 g/cap/a of polystyrene, 16 +/- 12 g/cap/a of expanded polystyrene, 65 +/- 36 g/cap/a of polyvinyl chloride, and 200 +/- 120 g/cap/a of polyethylene terephthalate enter the Swiss environment. All polymers combined, 540 +/- 140 and 73 +/- 14 g/cap/a are emitted into soil as macroplastics and microplastics, respectively, and 13.3 +/- 4.9 and 1.8 +/- 1.1 g/cap/a are emitted into freshwater as macroplastics and microplastics, respectively. The leading emission pathway is littering for both terrestrial and aquatic environments. Construction, agriculture, and pre- and postconsumer processes cause important emissions of microplastics into soils, and postconsumer processes, textiles, and personal care products release most of the microplastics into waters. Because mass flows into soils are predicted to be 40 times larger than those into waters, more attention should be placed on this compartment. Our work also highlights the importance of referring to specific polymers instead of just "plastics".