ENTPE, INRA, CNRS UMR 5023 LEHNA, rue Maurice Audin, 69518 Vaulx-en-Velin Cedex, France.
Irstea - Groupement de Lyon, Unité de recherche Milieux Aquatiques, Ecologie et Pollutions (MAEP), 5 rue de la Doua, 69626 Villeurbanne Cedex, France.
Sci Total Environ. 2017 Apr 15;584-585:1012-1021. doi: 10.1016/j.scitotenv.2017.01.154. Epub 2017 Feb 4.
Wastewater treatment plants (WWTPs) are one of the main sources of freshwater pollution eventually resulting in adverse effects in aquatic organisms. Treated effluents can contain many micropollutants at concentrations often below the limit of chemical quantification. On a regulatory basis, WWTP effluents have to be non-toxic to the aquatic environment, wherefore not only chemical abatement but also ecotoxicological evaluation through relevant bioassays is required. Standardized bioassays currently used are often not sensitive enough to reveal a residual toxicity in treated effluents. Therefore, attention must be paid to the development of better-adapted approaches implementing more sensitive organisms and relevant endpoints. In this study, the toxicity of two differently treated effluents (activated sludge treated effluents with and without ozonation) towards the ecologically relevant species Gammarus fossarum was evaluated. Organism fitness traits such as reproduction and sperm DNA integrity were followed in exposed organisms. In complement, enzymatic biomarkers were measured indicating the presence of neurotoxic compounds (acetylcholinesterase activity), the presence of pathogens likely to increase the toxic effects of chemical compounds (phenol-oxidase activity), and the presence of toxic compounds inducing detoxification mechanisms (glutathione-S-transferase activity). Enzymatic activities were not modified, but significant sub-lethal effects were observed in exposed organisms. In both effluents, females showed a retarded molt cycle, a reduced fecundity and fertility, and >90% of developed embryos exhibited developmental malformations. In addition, a slight but significant genotoxic effect was measured in gammarid sperm. In a whole, no difference in toxicity was found between both effluents. Coupling reproduction impairment and genotoxicity assessment in Gammarus fossarum seems to be a valuable and sensitive tool to reveal residual toxicity in effluents containing a mixture of micropollutants at very low concentrations. Finally, a direct relationship between the observed toxic responses and the quantified micropollutant concentrations could not be evidenced.
污水处理厂（WWTP）是淡水污染的主要来源之一，最终会对水生生物产生不利影响。处理过的废水中可能含有许多浓度通常低于化学定量极限的微量污染物。根据法规，WWTP 流出物必须对水生环境无毒，因此不仅需要进行化学减排，还需要通过相关生物测定进行生态毒理学评估。目前使用的标准化生物测定通常不够敏感，无法揭示处理废水中的残留毒性。因此，必须注意开发更好的方法，使用更敏感的生物和相关终点。在这项研究中，评估了两种不同处理的废水（未经臭氧处理和经臭氧处理的活性污泥废水）对生态相关物种罗氏沼虾的毒性。在暴露的生物体内，跟踪了生殖和精子 DNA 完整性等生物适应性特征。此外，还测量了酶生物标志物，以指示存在神经毒性化合物（乙酰胆碱酯酶活性）、可能增加化学化合物毒性效应的病原体（苯酚氧化酶活性）以及诱导解毒机制的有毒化合物（谷胱甘肽-S-转移酶活性）。酶活性没有改变，但在暴露的生物体内观察到明显的亚致死效应。在两种废水中，雌性表现出蜕皮周期延迟、繁殖力和生育力降低，超过 90%发育中的胚胎表现出发育畸形。此外，在栉虾精子中还测量到轻微但显著的遗传毒性效应。总的来说，两种废水中的毒性没有差异。在罗氏沼虾中结合生殖损伤和遗传毒性评估似乎是一种有价值和敏感的工具，可以揭示含有非常低浓度混合微量污染物的废水中的残留毒性。最后，没有证据表明观察到的毒性反应与定量的微量污染物浓度之间存在直接关系。
