Microplastics: A Multidimensional Threat to Environment, Economy, and Public Health

Microplastics, commonly defined as plastic particles smaller than 5 mm, have emerged as pervasive contaminants across natural and anthropogenic systems, constituting a complex global stressor with environmental, economic, and public health implications.Since the term microplastic was first introduced in 2004, an expanding body of research has revealed the extensive diversity and abundance of these particles, which originate from both the fragmentation of larger plastic debris (secondary microplastics) and the intentional production of microscopic polymers (primary microplastics) for use in cosmetics, industrial abrasives, and synthetic textiles.Despite substantial scientific attention, the absence of a universally accepted classification framework-particularly with respect to size ranges, polymer composition, and source attribution-continues to hinder harmonized monitoring and regulatory action.Microplastics have been detected in marine and freshwater environments, terrestrial soils, atmospheric fallout, and remote regions, demonstrating their capacity for longrange transport through hydrological, atmospheric, and biogeochemical processes.Ecologically, exposure has been shown to impair feeding behavior, induce physical obstruction, and compromise reproductive success across multiple trophic levels, from planktonic organisms to higher vertebrates.Chemically, microplastics function as dynamic carriers for persistent organic pollutants, heavy metals, and microbial assemblages.Human exposure has been increasingly documented through dietary intake, drinking water consumption, and inhalation of airborne particles.Effective mitigation of microplastic pollution will require coordinated international policy frameworks, advances in materials innovation and waste management, standardized analytical methodologies, and sustained public engagement to address both sources and impacts of microplastic contamination.