Tire wear particles in aquatic environments: A systematic review of sources, detection, distribution, and toxicological impacts

Tire wear particles (TWP), microplastic fragments generated through abrasion and volatilization, represent an emerging contaminant in aquatic ecosystems due to continuous input via stormwater runoff. This study screened 671 articles and conducted a bibliometric analysis of TWP research published between 2004 and 2024. The review synthesizes findings on TWP sources, detection methods, environmental distribution, and ecotoxicological impacts. Use phase was identified as a major emission source, closely linked to frictional forces. Current detection methods remain non-standardized, particularly within complex environmental matrices, limiting comparability across studies and resulting in sparse distribution data, especially for marine systems. Elevated concentrations reported in surface water and road runoff suggest ecological risks associated with TWP presence. Sediments consistently exhibit higher accumulation, confirming their role as long-term sinks. Toxicological evidence indicates adverse effects from TWP particles and leachates through physical properties, adsorption, and the release of chemicals, with priority toxicants including 6PPD-Q, zinc, and benzothiazole. However, mechanisms of action remain unclear, and laboratory exposures often exceed environmental levels. This review integrates quantitative data across aquatic compartments, identifies key toxicants, and highlights methodological gaps in detection. We emphasize the urgent need for standardized detection protocols, environmentally relevant toxicity testing, and regulatory measures to mitigate TWP pollution in aquatic systems.