Leaching potentials of microplastic fibers and UV stabilizers from coastal-littered face masks

Synthetic fibrous textiles are ubiquitous plastic commodities in everyday existence. Nevertheless, there exists a dearth of understanding regarding their environmental occurrence and the releasing capacities of associated additives. In this study, ten additives were determined in twenty-eight kinds of daily used plastic products including face masks, synthetic clothing, and food containers. Our results revealed that a typical kind of fibrous plastic, face masks, contained a greater variety of additives with UV stabilizers in particular, when compared to other plastic commodities. The above phenomena triggered our field investigation for the occurrence and release potentials of face mask fibers and the co-existing UV stabilizers into the environment. We further collected 114 disposed masks from coastal areas and analyzed their UV stabilizer concentrations. Results showed that the abundance of littered face masks ranged from 40-1846 items/km² along the Yangtze Estuary, China; and UV stabilizers were of 0.3 ± 0.7 ng/g and 0.7 ± 1.7 ng/g in main bodies and ear ropes, respectively. The UV stabilizer concentrations in the field collected masks were only ∼7 % of their new counterparts, implying their potential leaching after disposal. By simulating the weathering scenario, we predict that a substantial amount of microplastics, with 1.1 × 10¹⁰ polypropylene fibers and 3.7 × 10¹⁰ polyester fibers, are probably be released daily into the coastal environment after face masks disposal; whereas the accompanied leaching amount of UV stabilizers was relatively modest under the current scenario.