Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill St, Montreal, QC H2Y 2E7, Canada.
Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill St, Montreal, QC H2Y 2E7, Canada.
Ecotoxicol Environ Saf. 2021 Oct 1;222:112483. doi: 10.1016/j.ecoenv.2021.112483. Epub 2021 Jul 5.
Municipal wastewater treatment plant (WWTP) effluents are significant sources of organic and inorganic pollutants to aquatic ecosystems. Several studies have shown that the health of aquatic organisms can be adversely impacted following exposure to these complex chemical mixtures. The objective of this study was to examine the effects of in situ exposure in the St. Lawrence River (QC, Canada) of juvenile yellow perch (Perca flavescens) to a major WWTP effluent. Perch were caged at a reference site in the St. Lawrence River and downstream of a WWTP effluent-influenced site for one, three, and six weeks. Fish kept in controlled laboratory setting were also examined at the beginning of the experiment to evaluate the potential effect of caging on fish. Liver metabolites and gill oxidative stress biomarkers as well as body condition of perch were investigated at four time points (zero, one, three, and six weeks). Nitrogen (δN) and carbon (δC) stable isotopes as well as tissue concentrations of halogenated flame retardants and trace metals were also analyzed. Results indicated that body condition of perch caged in the effluent increased after three and six weeks of exposure compared to that of reference fish. Perch caged at the WWTP effluent-influenced site also had higher muscle δC and slightly depleted muscle δN after three and six weeks of exposure, suggesting differences in sewage-derived nutrient assimilation between sites. Concentrations of Σ polybrominated diphenyl ether (PBDE) were 2-fold greater in perch exposed downstream of the WWTP compared to those caged at the reference site. Metal concentrations in kidney of perch after three weeks of exposure were significantly lower at the effluent-influenced site. Kidney concentrations of Cd, Cu, Se, As, Zn and Fe were, however, higher after six weeks of exposure, supporting that metal accumulation is time- and element-specific. The metabolomes of perch from the effluent-influenced and reference sites were similar, but were distinct from the laboratory control fish, suggesting a caging effect on fish. Seven liver metabolites (glucose, malate, fumarate, glutamate, creatinine, histamine, and oxypurinol) were significantly more abundant in perch from cages than in the laboratory control perch. The combination of metabolomics and physiological variables provides a powerful tool to improve our understanding of the mechanisms of action of complex environmental pollutant mixtures in wild fish.
城市污水处理厂（WWTP）废水是水生生态系统中有机和无机污染物的重要来源。多项研究表明，水生生物在接触这些复杂的化学混合物后，其健康会受到不利影响。本研究的目的是研究在圣劳伦斯河（加拿大魁北克省）中，幼年黄鲈（Perca flavescens）体内原位暴露于主要 WWTP 废水的影响。黄鲈被关在圣劳伦斯河的参考点和 WWTP 废水影响点的笼子里，分别进行了 1、3 和 6 周的暴露实验。在实验开始时，还对在受控实验室环境中饲养的鱼类进行了检查，以评估笼子对鱼类的潜在影响。在四个时间点（零、一、三、六周），对黄鲈的肝脏代谢物和鳃氧化应激生物标志物以及身体状况进行了调查。还分析了氮（δN）和碳（δC）稳定同位素以及卤代阻燃剂和痕量金属的组织浓度。结果表明，与参考鱼类相比，在废水笼中饲养的黄鲈在暴露 3 周和 6 周后身体状况有所改善。在 WWTP 废水影响点笼中饲养的黄鲈在暴露 3 周和 6 周后肌肉 δC 更高，肌肉 δN 略有耗尽，这表明不同地点对污水衍生营养物质的同化存在差异。与参考点笼子中的黄鲈相比，在 WWTP 下游暴露的黄鲈中聚溴二苯醚（PBDE）的浓度高出 2 倍。暴露 3 周后，受废水影响点的黄鲈肾脏中的金属浓度明显降低。然而，在暴露 6 周后，黄鲈肾脏中的 Cd、Cu、Se、As、Zn 和 Fe 浓度更高，这表明金属积累具有时间和元素特异性。来自废水影响点和参考点的黄鲈的代谢组相似，但与实验室对照鱼不同，这表明笼子对鱼有影响。来自笼子的黄鲈肝脏中有 7 种代谢物（葡萄糖、苹果酸、富马酸、谷氨酸、肌酸酐、组氨酸和黄嘌呤）的含量明显高于实验室对照黄鲈。代谢组学和生理变量的结合提供了一种强大的工具，可以提高我们对野生鱼类中复杂环境污染物混合物作用机制的理解。
