Tire wear particles (TWP) represent a distinctive form of microplastics (MPs) that are widely distributed in aquatic ecosystems. However, the toxicity of various types of TWP on phytoplankton remain to be further explored. Thus, three different TWPs originating from replaced bicycle, car, and electro-mobile tire (marked as BTWP, CTWP, and ETWP) were selected and their long-term biological influences on Chlorella vulgaris were investigated. Results demonstrated TWPs showed a concentration-dependent growth promotion of Chlorella vulgaris, with a maximum promotion rate reached to 40.51 % (10 mg/L, 10 d), 23.5 % (80 mg/L, 12 d), and 28.7 % (20 mg/L, 12 d) in the presence of BTWP, CTWP and ETWP, respectively. Meanwhile, TWPs could stimulate the secretion of EPS and induce oxidative stress. EPS analysis revealed the increase of polysaccharides could protect the cell from the direct contact with TWP particles. Moreover, the increased concentration of EPS also helps to induce the settlement of TWP and reduce the leachate release. The release of TWP into the environment could act as an accelerator for the growth of Chlorella vulgaris, which might further change the normal physicochemical behaviors of algae colony in aquatic system. Our findings provide new insights into the toxicity mechanism of TWPs on freshwater algae and valuable data on environmental risk assessment of TWPs.

中文翻译：

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轮胎磨损颗粒对藻类生长、胞外聚合物物质产生和氧化应激的影响小球藻：性能与机制


轮胎磨损颗粒 （TWP） 是塑料微粒 （MP） 的一种独特形式，广泛分布在水生生态系统中。然而，各种类型的 TWP 对浮游植物的毒性仍有待进一步探索。因此，选择了源自替代自行车、汽车和电动移动轮胎（标记为 BTWP、CTWP 和 ETWP）的三种不同 TWP，并研究了它们对寻常小球藻的长期生物学影响。结果表明，TWPs 显示小球藻具有浓度依赖性的生长促进作用，在 BTWP、CTWP 和 ETWP 存在下，最大促进率分别达到 40.51 % （10 mg/L， 10 d） 、 23.5 % （80 mg/L， 12 d） 和 28.7 % （20 mg/L， 12 d）。同时，TWPs 可以刺激 EPS 的分泌并诱导氧化应激。EPS 分析显示，多糖的增加可以保护细胞免受 TWP 颗粒的直接接触。此外，EPS 浓度的增加也有助于诱导 TWP 的沉降并减少渗滤液的释放。TWP 释放到环境中可能成为小球藻生长的加速器，这可能会进一步改变水生系统中藻类群落的正常物理化学行为。我们的研究结果为 TWPs 对淡水藻类的毒性机制提供了新的见解，并为 TWPs 的环境风险评估提供了有价值的数据。