Predicting the global environmental distribution of plastic polymers*

This study represents the first quantitative global prediction of the mass distribution of six widespread polymers, plus plastic fibers and rubber across four environmental compartments and 11 sub-compartments. The approach used probabilistic material flow analysis for 2015, with model input values and transfer coefficients between compartments taken from literature. We estimated that 3.2 +/- 1.8 Mt/year of polyethylene, 1.3 +/- 0.8 Mt/year of polypropylene, 0.5 +/- 0.3 Mt/year of polystyrene, 0.3 +/- 0.15 Mt/year of polyvinyl chloride, 1.6 +/- 0.9 Mt/year of polyethylene terephthalate and 2.4 +/- 1.2 Mt/year of plastic fibers enter the environment. Combining all plastic, including rubber, 4.9 +/- 1.3, 4.8 +/- 1.9 and 1.8 +/- 1.2 Mt/year accumulated in the soil, ocean, and freshwater, respectively. Urban soils and ocean shorelines were predicted as hotspots for plastic accumulation, accounting for 33% and 25% of total plastic, respectively. The floor of freshwater systems and the ocean were predicted as hotspots for high density plastic such as polyethylene terephthalate, polyvinyl chloride and plastic fibers. Furthermore, 59% of environmental rubber was predicted to accumulate in soil. The findings of this study provide baseline data for quantifying plastic transport and accumulation, which can inform future ecotoxicity studies and risk assessments, as well as targeting efforts to mitigate plastic pollution.

Automated summary

This study provides the first quantitative global prediction of the distribution of various polymers, plastic fibers, and rubber in different environmental compartments. The findings highlight the accumulation of plastic in urban soils and ocean shorelines, as well as the concentration of high-density plastics in freshwater systems and the ocean. Additionally, a significant amount of environmental rubber is predicted to accumulate in soil.