The vector effect of microplastics and nanoplastics: co-transport and ecological risks of chemical pollutants and antibiotic resistance genes in the soil-water continuum.

Microplastics (MPs) and nanoplastics (NPs) act as dynamic environmental vectors across the soil-water continuum, allowing them to enter organisms through direct ingestion, leading to potential tissue accumulation. Under specific exposure conditions, these vectors can undergo trophic transfer through food chains, contributing to combined toxicological risks. This paper reviews how the adsorption and co-transport behaviors of chemical pollutants by MPs and NPs are collectively regulated by the intrinsic physicochemical properties of the material and environmental weathering processes. The formation of the "plastisphere" on the surface of these particles provides a physical substrate that selectively enriches microbial communities and mobile genetic elements (MGEs). Under specific combined chemical stresses, this localized enrichment can act as a precursor to facilitate the horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs), although the actual occurrence of HGT remains highly context-dependent. Additionally, MPs and NPs exacerbate their ecotoxicological impacts by operating via an "adsorption-ingestion-release" pathway within host gastrointestinal tracts, significantly influencing the dynamic bioavailability and combined toxicity (e.g., synergistic, antagonistic, or additive) of co-existing pollutants across multiple trophic levels. Given the numerous unresolved scientific challenges-such as the lack of standardized quantification methodologies for complex soil matrices and the poorly understood biomagnification of composite pollutant mixtures-there is a pressing need to promote further research through AI-driven coupled kinetic models and a comprehensive "One Health" risk assessment paradigm.