Tire-wear particles (TWPs) are potential source of microplastic (MP) pollution in marine environments. Although the hazardous effects of MPs on marine biota have received considerable attention, the toxicity of TWPs and associated leachates remain poorly understood. Here, to assess the toxicity of TWP leachate and the underlying mechanisms of toxicity, the phenotypic and transcriptomic responses of the rotifer Brachionus plicatilis were assessed with chemistry analysis of a TWP leachate. Although acute toxicity was induced, and a variety of metals and polyaromatic hydrocarbons were detected in the leachate, levels were below the threshold for acute toxicity. The results of particle analysis suggest that the acute toxicity observed in our study is the result of a toxic cocktail of micro- and/or nano-sized TWPs and other additives in TWP leachate. The adverse effects of TWP leachate were associated with differential expression of genes related to cellular processes, stress response, and impaired metabolism, with further oxidative stress responses. Our results imply that TWPs pose a greater threat to marine biota than other plastic particles as they constitute a major source of nano- and microplastics that have synergistic effects with the additives contained in TWP leachate.

轮胎磨损颗粒 (TWP) 是海洋环境中微塑料 (MP) 污染的潜在来源。尽管 MPs 对海洋生物群的有害影响已受到相当多的关注，但 TWPs 和相关渗滤液的毒性仍然知之甚少。在这里，为了评估 TWP 渗滤液的毒性和潜在的毒性机制，轮虫Brachionus plicatilis的表型和转录组学反应用 TWP 渗滤液的化学分析评估。尽管诱发了急性毒性，并且在渗滤液中检测到多种金属和多环芳烃，但水平低于急性毒性阈值。颗粒分析结果表明，我们研究中观察到的急性毒性是 TWP 渗滤液中微米和/或纳米尺寸 TWP 和其他添加剂的有毒混合物的结果。TWP 渗滤液的不良反应与细胞过程、应激反应和代谢受损相关基因的差异表达有关，并伴有进一步的氧化应激反应。我们的研究结果表明，与其他塑料颗粒相比，TWPs 对海洋生物群的威胁更大，因为它们构成了与 TWP 渗滤液中所含添加剂具有协同作用的纳米塑料和微塑料的主要来源。