Recent studies on the distribution of microplastics in the Charleston Harbor, SC, USA revealed that a large part of the microplastic particles that are found in the intertidal sediments are tire wear particles. These particles originate from the wear of tire treads on roadways, and wash into the estuary during rain events. The abundance of these particles has raised questions about potential toxicity to aquatic organisms that ingest these particles. The synthetic rubber in car tires consists of a large variety of chemicals, which can vary between manufacturers, but usually contains styrene-butadiene rubber, carbon black and zinc. To investigate the potential toxicity of tire wear particles, both mummichogs (Fundulus heteroclitus) and fathead minnow (Pimephales promelas) were exposed to different concentrations of crumb rubber particles (38-355 µm) in a 7-day static renewal exposure. Dissection of the fish revealed that crumb rubber was ingested and accumulated in the intestinal tract. At the highest concentration tested (6 g/L) partial mortality was observed in the fathead minnow, which came close to the assumed LC50. To investigate if polynuclear aromatic hydrocarbons (PAHs) were leaching from the particles, bile fluorescence was measured, together with potential induction of cytochrome P450-1A through the ethoxyresorufin-O-deethylase (EROD) assay. Elevated levels of 2-, 4-, and 5-, ring structures representative of PAHs were detected in the bile of exposed animals. Bile fluorescence indicated that 4-ring PAH compounds were the most bioavailable from the crumb rubber particles. Induction of EROD activity was observed in exposed animals at environmentally relevant concentrations of the crumb rubber particles (<1-2 g/L), and this elevated EROD activity indicated that PAH compounds from the crumb rubber particles were being metabolized in both mummichogs and fathead minnow.

中文翻译：

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微细轮胎屑橡胶对木乃伊（Fundulus heteroclitus）和黑头min鱼（Pimephales promelas）的毒理作用。

最近在美国南卡罗来纳州查尔斯顿港的微塑料分布研究表明，潮间带沉积物中发现的大部分微塑料颗粒是轮胎磨损颗粒。这些颗粒源于道路上轮胎胎面的磨损，在下雨时会冲入河口。这些颗粒的丰富性引起了对摄入这些颗粒的水生生物潜在毒性的疑问。汽车轮胎中的合成橡胶包含多种化学物质，制造商之间可能会有所不同，但通常包含丁苯橡胶，炭黑和锌。为了研究轮胎磨损颗粒的潜在毒性，在7天的静态更新暴露中，将木乃伊（Fundulus heteroclitus）和黑头now鱼（Pimephales promelas）都暴露于不同浓度的面包屑橡胶颗粒（38-355 µm）。鱼的解剖显示，碎胶被摄入并积聚在肠道中。在测试的最高浓度（6 g / L）下，黑头fat鱼观察到部分死亡，接近假定的LC50。为了研究是否从颗粒中浸出了多核芳香烃（PAHs），测量了胆汁荧光，并通过乙氧基试卤灵-O-脱乙基酶（EROD）分析潜在诱导了细胞色素P450-1A。在暴露的动物的胆汁中检测到代表PAHs的2、4和5环结构水平升高。胆汁荧光表明四环PAH化合物从碎屑橡胶颗粒中生物利用度最高。在暴露的动物中，在与环境有关的浓度的碎屑橡胶颗粒（<1-2 g / L）中观察到EROD活性的诱导，并且这种升高的EROD活性表明，碎屑橡胶颗粒中的PAH化合物在木乃伊和黑头中均被代谢。桃花鱼。