It is snowing microplastics in Western Siberia.

The atmosphere is an important transport medium for polymeric anthropogenic particles such as microplastics (MPs). The analysis of particles deposited on the snowpack enables monitoring the abundance and transport of MPs and semi-synthetic fibers. In the current study, the abundance of MPs and man-made textile fibers in deposited snow in Western Siberia, Russia, was investigated in a large area ranging from the Altai Mountains (52°01″N) to the Arctic Circle (66°30″N). Rayon fibers accounted for 44% of all detected particles, while the remaining 56% were MPs made of PET, PA, PC, PP and other plastics. The highest number of MPs and fibers per unit area was 2817 ± 915 items m with an estimated daily deposition rate of 25.8 items m d. The maximum calculated mass particle load was 4444 ± 1530 mg m or 34.9 ± 12 mg L of melted snow. Particle concentrations in snow were generally higher in the southern parts of Western Siberia but did not significantly correlate with population density. The Lagrangian dispersion model FLEXPART was used to estimate the geographical patterns of potential sources of the fibers detected in the snow in Western Siberia. Our analysis shows that particles can reach the sampling sites via both short-range and long-range atmospheric transport, including the possibility of cross-border transport for the smaller particle sizes.