Emerging Organic Contaminants in the Third Pole Region: Sources, Transport, and Associated Risks

The Third Pole (TP) region, encompassing the Tibetan Plateau and surrounding alpine ecosystems, experiences significant anthropogenic impacts despite its remote nature. Long-range atmospheric transport (LRAT) and local emissions introduce both commercially produced chemicals and unintentionally released contaminants into this vulnerable region. Among these chemicals, many organic pollutants have not been extensively monitored in the TP, yet pose potential risks to human health and the environment, thus constituting an emerging concern for the region. These substances are known as emerging organic contaminants (EOCs). The TP serves as a unique model for studying pollutant migration and fate. Research on EOCs in this region not only confirms the LRAT behaviors of these compounds but also enhances our understanding of their environmental interactions, providing a scientific basis for effective pollutant regulation. Here, we offer an up-to-date summary of the distributions of EOCs across various environmental matrices and biota within the TP. This review aims to illustrate their potential sources, transport pathways, environmental fate, as well as ecological and human risks they pose in this sentinel region. We emphasize that EOCs are transported from surrounding source regions to the TP via LRAT, with deposition significantly heightened by concurrent cold trapping and forest filter effects. Furthermore, the intensification of local anthropogenic activities, coupled with the rerelease of both EOCs and legacy POPs under the impacts of global warming, exacerbates their impact on TP ecosystems. Finally, we propose several key research priorities for the future, highlighting the need for long-term multimedia monitoring to elucidate distribution patterns, origins, and transport pathways of EOCs. We call for enhanced regional and international research programs to better understand the various biogeochemical and geophysical processes influenced by climate change and anthropogenic pressures.