Abstract：
The aquatic ecological risks posed by the surface-active components of tire wear particles (TWPs) are not fully understood. This study aimed to determine the acute (24 h exposure) aquatic toxicity effects of TWPs on freshwater biofilms in terms of total organic carbon (TOC), chlorophyll-a (Chl-a) abundance, quantum yield (ФM), and adenosine triphosphate (ATP). Three types of TWP were tested: TWPs produced via the typical wear of tires and roads (i.e., rolling friction (R-TWPs) and sliding friction (S-TWPs)) and cryogenically milled tire treads (C-TWPs). The results showed that the surface structural properties of the three TWPs differed significantly in morphology, bare composition, functional groups, and surface-active components (environmental persistent free radicals). The exposure of biofilms to the TWPs increased TOC and ATP at low concentrations (1 mg L-1) but inhibited them at high concentrations (50 mg L-1). All TWP types inhibited biofilm photosynthesis (reduced Chl-a and ФM) and altered the community structure of algae to varying degrees; in addition, the toxicity mechanisms of the TWPs contributed to the accumulation of reactive oxygen species and cell membrane (or cell-wall) fragmentation, leading to lactate dehydrogenase release. S-TWPs were the most toxic because their surface carried the highest environmental persistent free radicals. R-TWPs were the second most toxic, which was attributed to their smaller particle size. The toxicity of all TWPs was tested after sewage incubation aging. The results showed that the toxicity of all TWPs reduced as the sewage covered their surface components and active sites. This process also reduced the differences in toxicity among the TWPs. This study filled a research gap in our understanding of aquatic toxicity caused by the surface structural properties of tire microplastics and has implications for the study of microplastic biotoxicity mechanisms.
摘要：
尚未完全了解轮胎磨损颗粒（TWP）的表面活性成分所带来的水生生态风险。本研究旨在确定TWP对总有机碳（TOC）淡水生物膜的急性（24小时暴露）水生毒性影响。叶绿素a（Chl-a）丰度，量子产率(ΦM)，和三磷酸腺苷（ATP）。测试了三种类型的TWP：通过轮胎和道路的典型磨损产生的TWP（即，滚动摩擦（R-TWP）和滑动摩擦（S-TWP））和低温铣削轮胎胎面（C-TWP）。结果表明，三种TWP的表面结构性质在形貌上差异显著，裸露的成分，功能组，和表面活性成分（环境持久性自由基）。生物膜暴露于TWP会在低浓度（1mgL-1）时增加TOC和ATP，但在高浓度（50mgL-1）时抑制它们。所有TWP类型都抑制了生物膜的光合作用（减少了Chl-a和ΦM），并在不同程度上改变了藻类的群落结构；此外，TWP的毒性机制有助于活性氧的积累和细胞膜（或细胞壁）的破碎，导致乳酸脱氢酶释放。S-TWP毒性最大，因为它们的表面携带最高的环境持久性自由基。R-TWP是第二大毒性,这归因于它们的粒径较小。在污水孵育老化后测试所有TWP的毒性。结果表明，随着污水覆盖其表面成分和活性位点，所有TWP的毒性均降低。该过程还减少了TWP之间的毒性差异。这项研究填补了我们对轮胎微塑料表面结构特性引起的水生毒性的理解的研究空白，并对微塑料生物毒性机制的研究具有启示意义。
