Microplastics (MPs) and glyphosate‐based herbicides (GBH) are among the most common contaminants in aquatic environments. In Brazilian rivers, both contaminants were found in elevated levels, leading to a high probability of their association, which can alter their individual effects and potentially intensify their toxicity. This study evaluated the isolated and combined effects of polyethylene microplastics (PE‐MPs) and GBH on Oreochromis niloticus using multi‐biomarkers of toxicity. The fish were subjected to a 96‐h exposure period, with concentrations set based either isolated, PE‐MPs group (5 mg L−1), GBH group (5 mg L−1), or in a group of associated contaminants (GAC), PE‐MP + GBH (5 mg L−1 + 5 mg L−1). Toxicity effects were evaluated using biochemical, cytogenetic, hematological, and histopathological biomarkers. We observed change in erythrocyte parameters leading to macrocytic normochromic anemia in GAC. Leukocyte parameters indicate a nonspecific immunosuppression caused by the exposure of associated contaminants, besides the attempts to repair damage caused by PE‐MPs. Histopathological markers indicate damage to tissues exposed to contaminants. Besides, there were morphophysiological adjustments on gills, with proliferation and hypertrophy of mitochondria‐rich cells on GBH and GAC, besides epithelium ruptures, which were mostly present in the exposed groups. Therefore, this study indicates that PE‐MPs and GBHs present toxic effects in O. niloticus with the used concentrations, intensified by the association of contaminants. Thus, multi‐biomarkers were useful key to verify toxicity, providing data to the investigation of high levels of contaminant's mixture toxicity present in aquatic environments.

中文翻译：

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暴露于草甘膦和聚乙烯微塑料、分离和混合物的 Oreochromis niloticus 鳃中的多生物标志物反应


微塑料 （MP） 和基于草甘膦的除草剂 （GBH） 是水生环境中最常见的污染物之一。在巴西河流中，这两种污染物的含量都很高，导致它们很有可能相互关联，这可能会改变它们的个体影响并可能加剧它们的毒性。本研究使用多种毒性生物标志物评估了聚乙烯微塑料 （PE-MP） 和 GBH 对尼罗河奥色菌的分离和综合影响。鱼经过 96 小时的暴露期，浓度设置基于分离的 PE-MPs 组 （5 mg L-1）、GBH 组 （5 mg L-1） 或一组相关污染物 （GAC），PE-MP + GBH （5 mg L-1 + 5 mg L-1）。使用生化、细胞遗传学、血液学和组织病理学生物标志物评估毒性效应。我们观察到红细胞参数的变化导致 GAC 中的大细胞正色素性贫血。白细胞参数表明，除了试图修复 PE-MPs 造成的损伤外，还由相关污染物的暴露引起的非特异性免疫抑制。组织病理学标志物表明暴露于污染物的组织受损。此外，鳃存在形态生理调整，GBH 和 GAC 上富含线粒体的细胞增殖和肥大，除了上皮破裂外，主要存在于暴露组中。因此，本研究表明，PE-MPs 和 GBHs 在所用浓度下对 O. niloticus 具有毒性作用，并因污染物的结合而加剧。因此，多生物标志物是验证毒性的有用关键，为研究水生环境中存在的高水平污染物混合物毒性提供数据。