In order to estimate the effects on aquatic organisms of long-term exposure to low doses of yttrium (Y) as a potential emerging contaminant, ecotoxicological and metabolomic data were collected on the model organism Daphnia magna, a keystone species in freshwater ecosystems. Following an initial acute toxicity assessment, a 21-day chronic exposure experiment was conducted using a sublethal concentration of 27 μg L⁻¹ of Y, corresponding to the effective concentrations inducing 10 % effect (EC10) value for mortality endpoint and simulating the environmental Y level in aquatic systems. Results from the 21-day two-factor experiment combining microcrustacean survival, growth and reproduction bioassays and targeted gas chromatography-mass spectrometry (GC–MS) metabolomics indicated significant adverse effects of chronic exposure to Y on D. magna. Daphnids exposed to Y exhibited a significantly lower survival at day 21, delayed the maturity stage, including their first breeding, and decreased clutch size. On the side of metabolomics, a clear and general increase over time of both the number and the level of detected metabolites in the hydroalcoholic extracts of the whole organisms was observed. However, emerging from this broad temporal pattern, several bioactive metabolites were identified (e.g., 2,4-di‑tert‑butylphenol, itaconic acid, 3-hydroxybutyric acid, and trehalose) whose levels in extracts are linked to the presence of Y. These results emphasize the necessity of considering low-dose, long-term exposure scenarios in environmental risk assessments of rare earth elements (REEs), which have often been overlooked in favour of higher concentration studies.

中文翻译：

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大溞 （Straus， 1820） 长期暴露于钇环境浓度的生态毒理学和代谢组学研究


为了估计长期暴露于低剂量钇 （Y） 作为潜在新兴污染物对水生生物的影响，收集了模式生物 Daphnia magna（淡水生态系统中的关键物种）的生态毒理学和代谢组学数据。在初步急性毒性评估后，使用 27 μg L⁻¹ 的亚致死浓度 Y 进行了为期 21 天的慢性暴露实验，对应于诱导 10 % 效应 （EC10） 值的有效浓度作为死亡率终点，并模拟水生系统中的环境 Y 水平。将微甲壳类动物存活、生长和繁殖生物测定与靶向气相色谱-质谱 （GC-MS） 代谢组学相结合的 21 天双因素实验的结果表明，长期暴露于 Y 对 D. magna 有显着的不利影响。暴露于 Y 的 Daphnids 在第 21 天表现出显着较低的存活率，延迟了成熟阶段，包括它们的第一次繁殖，并且窝大小减小。在代谢组学方面，观察到整个生物体的水醇提取物中检测到的代谢物的数量和水平随着时间的推移而明显而普遍地增加。然而，从这种广泛的时间模式中，确定了几种生物活性代谢物（例如，2,4-二叔丁基苯酚、衣康酸、3-羟基丁酸和海藻糖），其提取物中的水平与 Y 的存在有关。这些结果强调了在稀土元素 （REE） 的环境风险评估中考虑低剂量、长期暴露情景的必要性，这些情景经常被忽视，以支持更高浓度的研究。