Engineered Nanomaterials in Sports and Their Environmental and Health Implications

Engineered nanomaterials (ENMs) are used or investigated in sports for mechanical reinforcement, friction regulation, thermal management, biosensing, energy harvesting, and tissue repair. This critical review examines their applications, environmental release, transformation, exposure pathways, biological interactions, and end-of-life management, distinguishing field measurements, laboratory tests, models, and proposed pathways. ENMs are deliberately engineered for nanoscale functionality; microplastics (MPs) and nanoplastics (NPs) are classified by polymer composition and size. Micro(nano)plastics (MNPs) are not inherently nanomaterials; nanoscale polymer particles may be engineered or incidental. MNPs from synthetic turf, polymeric infill, running tracks, footwear, and apparel are assessed as degradation products, potential carriers of embedded ENMs, and co-occurring contaminants. Field evidence is stronger for turf-derived MP release than for sports-related free ENM or NP release. Abrasion, oxidation, and weathering modify particle size, surface chemistry, and sorption capacity, while hydrological runoff, wind transport, and human activities redistribute particles. Athlete exposure through inhalation, ingestion, and dermal contact is plausible, but limited longitudinal biomonitoring warrants cautious interpretation of health risks. Laboratory ecotoxicological studies identify material- and preparation-dependent hazards to terrestrial and aquatic biota, but do not establish effects at measured sports-field drainage concentrations. Sustainability requires low-emission material design, effective physical containment, advanced drainage treatment, environmentally realistic exposure testing, transparent material disclosure, and robust end-of-life recovery systems. Circularity metrics must incorporate diffuse particulate and chemical emissions into life-cycle exposure and ecosystem risk assessments. Comparative synthesis links material properties, release identity, analytical limits, and pathway confidence; a minimum reporting framework identifies the measurements needed for quantitative exposure and risk assessment.