Cocktail Effects of Tire Wear Particles Leachates on Diverse Biological Models: A Multilevel Analysis

Tire wear particles (TWP) stand out as a major contributor to microplastic pollution, yet their environmental impact remains inadequately understood. This study delves into the cocktail effects of TWP leachates, employing molecular, cellular, and organismal assessments on diverse biological models. Extracted in artificial seawater and analyzed for metals and organic compounds, TWP leachates revealed the presence of polyaromatic hydrocarbons and 4-tert-octylphenol. Exposure to TWP leachates (1.5 to 1000 mg peq L−1) inhibited algae growth and induced zebrafish embryotoxicity, pigment alterations, and behavioral changes. Cell painting uncovered pro-apoptotic changes, while mechanism-specific gene-reporter assays highlighted endocrine-disrupting potential, particularly antiandrogenic effects. Although heavy metals like zinc have been suggested as major players in TWP leachate toxicity, this study emphasizes water-leachable organic compounds as the primary causative agents of observed acute toxicity. The findings underscore the need to reduce TWP pollution in aquatic systems and enhance regulations governing highly toxic tire additives. Environmental Implication Statement Tire wear particles (TWP) pose a significant environmental threat, contributing to microplastic pollution and releasing harmful chemical contaminants. This study unveils the hazardous nature of TWP leachates, introducing detrimental compounds to aquatic ecosystems. Identified pollutants, notably polyaromatic hydrocarbons, induce acute toxicity, impede algae growth, induce embryotoxicity, alter behavior, and disrupt signaling pathways. These revelations emphasize TWP as a hazardous material affecting aquatic life at multiple levels, posing risks to the health of both ecosystems and, potentially, human well-being. Enhancing our understanding of TWP leachate mechanisms is crucial for mitigating these risks and safeguarding aquatic ecosystems from deleterious effects.