The toxic effects of tire wear particles (TWPs) on organisms have attracted widespread concerns over the past decade. However, the underlying toxicity mechanism of TWPs, especially aged TWPs to marine microalgae remains poorly understood. This study investigated the physiological and metabolic responses of to different concentrations of TWPs (Experiment 1), virgin and differently aged TWPs (Experiment 2) as well as their leachates and leached particles (Experiment 3). Results demonstrated that TWPs promoted the growth of microalgae at low concentrations (0.6 and 3 mg ) and inhibited their growth at high concentrations (15 and 75 mg ). Moreover, aged TWPs induced more profound physiological effects on microalgae than virgin TWPs, including inhibiting microalgae growth, decreasing the content of , promoting photosynthetic efficiency, and causing oxidative damage to algal cells. Untargeted metabolomics analysis confirmed that aged TWPs induced more pronounced metabolic changes than virgin TWPs. This study represented the first to demonstrate that both particulate- and leachate-induced toxicity of TWPs was increased after aging processes, which was confirmed by the changes in the surface morphology of TWPs and enhanced release of additives. Through the significant correlations between the additives and the microalgal metabolites, key additives responsible for the shift of microalgal metabolites were identified. These results broaden the understanding of the toxicity mechanism of aged TWPs to microalgae at the physiological and metabolic levels and appeal for considering the effects of long-term aging on TWP toxicity in risk assessment of TWPs.

中文翻译：

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老化增加了轮胎磨损颗粒对微藻的颗粒物和渗滤液引起的毒性

在过去的十年中，轮胎磨损颗粒（TWP）对生物体的毒性作用引起了广泛的关注。然而，TWP，尤其是老化的TWP对海洋微藻的潜在毒性机制仍知之甚少。本研究调查了不同浓度的TWP（实验1）、原始和不同老化的TWP（实验2）及其浸出液和浸出颗粒（实验3）的生理和代谢反应。结果表明，TWP 在低浓度（0.6 和 3 mg）时促进微藻生长，在高浓度（15 和 75 mg）时抑制微藻生长。此外，与原始TWP相比，老化的TWP对微藻产生更深远的生理影响，包括抑制微藻生长、降低α含量、提高光合效率以及对藻细胞造成氧化损伤。非靶向代谢组学分析证实，老化的 TWP 比原始 TWP 诱导更明显的代谢变化。这项研究首次证明，TWP 的颗粒物和渗滤液引起的毒性在老化过程后会增加，TWP 表面形态的变化和添加剂释放的增强证实了这一点。通过添加剂与微藻代谢物之间的显着相关性，确定了导致微藻代谢物转变的关键添加剂。这些结果拓宽了对老化TWP在生理和代谢水平对微藻的毒性机制的理解，并呼吁在TWP风险评估中考虑长期老化对TWP毒性的影响。