Micro- and nanoplastic pollution in wetland ecosystems: Ecological risks, health implications, and mitigation strategies toward a One Health future.

Wetland ecosystems are among the world's most productive and valuable environments, supporting key ecosystem functions, such as biodiversity conservation and water quality improvement, carbon sequestration, flood buffering, and climate resilience. However, the widespread occurrence of micro- and nanoplastics (MNPs) has emerged as a growing threat to the ecological integrity and functioning of these ecosystems. Individual MNPs and the combined effects of these particles and coexisting microcontaminants represent a major threat to environmental and human health. Wetlands act as both sinks and secondary sources of MNPs due to their unique hydrological, biological, and sedimentary characteristics, facilitating the accumulation, transformation, and redistribution of plastic particles. Once trapped in wetland environments, MNPs experience physical, chemical, and biological transformation processes, interact with co-occurring contaminants and microbial communities, and may be transported across aquatic and terrestrial food webs, thereby threatening wildlife, livestock, and ultimately human health. These processes highlight the need to investigate MNP pollution within a One Health framework to develop mitigation strategies to protect ecosystems, wildlife, and human health.