Million tons of tires become waste every year, and the so-called End-of-Life Tires (ELTs) are ground into powder (ELT-dp; size < 0.8 mm) and granules (ELT-dg; 0.8 < size < 2.5 mm) for recycling. The aim of this study was to evaluate the sub-lethal effects of three different concentrations (0.1, 1, and 10 mg/L) of aqueous suspensions from ELT-dp and ELT-dg on Danio rerio (zebrafish) larvae exposed from 0 to 120 h post-fertilization (hpf). Chronic effects were assessed through biomarkers, real-time PCR, and proteomics. We observed a significant increase in swimming behavior and heart rate only in specimens exposed to ELT-dp suspensions at 1 and 10 mg/L, respectively. Conversely, the activities of detoxifying enzymes ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase (GST) showed significant modulation only in specimens exposed to ELT-dg groups. Although no effects were observed through real-time PCR, proteomics highlighted alterations induced by the three ELT-dp concentrations in over 100 proteins involved in metabolic pathways of aromatic and nitrogen compounds. The results obtained suggest that the toxic mechanism of action (MoA) of ELT suspensions is mainly associated with the induction of effects by released chemicals in water, with a higher toxicity of ELT-dp compared to ELT-dg.

中文翻译：

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传统（微）塑料的背后：报废轮胎颗粒中水性悬浮液的生态毒理学表征


每年有数百万吨轮胎成为废料，所谓的报废轮胎 （ELT） 被研磨成粉末（ELT-dp;尺寸 < 0.8 mm）和颗粒（ELT-dg;0.8 < 尺寸 < 2.5 mm）进行回收。本研究的目的是评估 ELT-dp 和 ELT-dg 的三种不同浓度 （0.1、1 和 10 mg/L） 水悬浮液对受精后 0 至 120 小时 （hpf） 暴露的 Danio rerio（斑马鱼）幼虫的亚致死影响。通过生物标志物、实时 PCR 和蛋白质组学评估慢性影响。我们仅在分别暴露于 1 和 10 mg/L 的 ELT-dp 悬浮液的标本中观察到游泳行为和心率的显着增加。相反，解毒酶乙氧基间苯-O-脱乙基酶 （EROD） 和谷胱甘肽-S-转移酶 （GST） 的活性仅在暴露于 ELT-dg 组的标本中显示出显着调节。尽管通过实时 PCR 未观察到任何影响，但蛋白质组学强调了三种 ELT-dp 浓度在参与芳香族和氮化合物代谢途径的 100 多种蛋白质中诱导的变化。获得的结果表明，ELT 悬浮液的毒性作用机制 （MoA） 主要与水中释放的化学物质诱导作用有关，与 ELT-dg 相比，ELT-dp 的毒性更高。