High-mountain lakes as indicators of microplastic pollution: current and future perspectives

As a key component of mountain ecosystems, high-mountain lakes are recognized indicators of global change. In the analysis of the effects induced by local or global human activities, microplastic (MP) pollution is of critical environmental concern for mountain ecosystem compartments and for high-mountain lakes in particular. This minireview reports on current knowledge of MP occurrence, source, distribution, and characteristics in high-mountain lake ecosystems. The literature search returned only nine studies mainly from the Tibet plateau (China). Generally, the two most often investigated compartments were water and sediment, followed by snow and fish. Plastic particles were found as fragments and fibers of polypropylene and polyethylene, which are primarily utilized in food packaging and supplies brought by tourists and then discarded on site. Tourism and atmospheric long-range transport from lowlands were identified as the main sources of MP pollution. Precipitation events (snow and rain) were reported as key events in MP deposition and fallout. Further studies are needed to better understand the effects of MP pollution on aquatic food webs and ecosystem resources (e.g., drinking water) in these key ecosystems.