Assessing the Ecological Risks Posed by Microplastic Pollution of Snow Cover in Western Siberia

Atmospheric microplastic pollution is an emerging environmental concern, yet data on ecological risks posed by snow cover pollution remain sparse. This study presents the first assessment of ecological risks associated with snow cover pollution in Western Siberia. Pollution and risk levels were quantified using the pollution load index (PLI), the polymer hazard index (PHI), and the potential ecological risk index (PERI). Microplastics were detected in all snow samples; however, the pollution level was rated as ‘low’ across all sampling sites throughout the observation period. Although median PHI values for the snow cover indicated medium hazard, the presence of samples referred to the hazard categories ‘danger’ and ‘extreme danger’ (up to 27% in 2023) pointed to localized pollution by potentially toxic polymers. In contrast, the average PERI values remained low (1.92–19.7), as this index accounts for both polymer toxicity and microplastic abundance. However, the index showed a consistent upward trend over the three-year observation period, driven by the increase in both the proportion of hazardous polymers and the total microplastic load. Thus, although the quantitative content of microplastics in the snow cover of Western Siberia was low, the high PHI values at some sampling sites and the occurrence of polymers containing toxic monomers like polyacrylonitrile (PAN) and polyurethane (PU) indicate a potential ecological risk that requires further monitoring.