Current status and future perspectives of microplastic pollution in typical cryospheric regions

The cryosphere is the term used to describe the frozen areas of the Earth, including all forms of snow and ice, which are primarily influenced by anthropogenic pollutants through atmospheric transport. In this review, we described the current status of newly emergent pollutant-microplastics-in the snow and ice of typical cryospheric regions (e.g., Arctic, Antarctic, Alps, Tibetan Plateau, and Andes), discussed their transport pathways, and provided perspectives for future research. A brief summary of snow and ice sampling, pretreatment, and the identification of microplastics in cryospheric regions suggested that standard procedures were inadequate and urgently required improvement. Microplastics were widely distributed in snow and ice across the typical cryospheric regions, indicating the ubiquitous distribution of microplastics in such environments. However, the abundance, size distribution, shape, and polymer composition of the microplastics in snow and ice showed significant differences. Sea ice was especially important for the temporal storage, transport, and release of microplastics in the Arctic and Antarctic. Microplastics in land snow cover and mountain glaciers emphasized the importance of atmospheric transport in the transferal of microplastics to cryospheric regions. In particular, the non-polar cryospheric regions (e.g., Tibetan Plateau, Andes, or Alps) were highlighted as important receptors of mid-latitude emissions of microplastics, which might indicate a future climatic risk considering the ability of microplastics to absorb radiation and accelerate the melting of snow. Microplastics retrieved from mountain glacier ice cores may also provide new insights into the historical variations of anthropogenic pollutants. The potential impact of microplastics in snow and ice on the carbon cycle and the climatic risk needs to be further addressed in the future.