Micro(nano)plastics as dynamic vectors for hazardous agents: Bridging environmental transport to health impacts.

The pervasive accumulation of micro(nano)plastics (MNPs) in the environment establishes them as persistent contaminants, posing a significant threat to ecosystem integrity and human health. This review synthesizes the environmental journey of MNPs by framing them as dynamic colloidal particles and mechanistically tracing their pathway from source to biological uptake. We discuss fundamental interfacial processes, including DLVO and non-DLVO interactions, straining, and air-water interface capture, governing MNP mobility and retention in porous media. These processes control MNP dispersal and potential to contaminate groundwater and agricultural systems. The interplay of colloidal properties (size, shape, surface chemistry) with environmental parameters is examined to explain exposure routes. We also detail how this colloidal behavior dictates bioavailability, facilitating MNP uptake in plants and soil fauna and amplifying their role as vectors for co-contaminants and antibiotic resistance genes. Human biomonitoring studies reveal MNPs in blood, stool, placenta, and bronchoalveolar lavage fluid. Systematic review evidence indicates associations with cardiovascular inflammation, endothelial dysfunction, and fibrosis; in vitro studies demonstrate PS MP-induced reductions in human sperm motility, vitality, and fertility-related gene expression; and cross-sectional studies link higher fecal MNP concentrations to gut microbiota dysbiosis, including increased abundance of harmful bacteria and decreased beneficial taxa. However, causation remains unestablished due to methodological heterogeneity and the predominance of cross-sectional designs. By integrating colloid science with ecotoxicology and exposure science, this review bridges the gap between MNP physical transport and adverse health outcomes, provides a framework for risk assessment, and highlights urgent research priorities, including standardized methods, longitudinal studies, and human-relevant models.