Populations of the critically endangered freshwater mussel Pseudunio auricularius (Spengler, 1793) have been suffering sharp declines, particularly in the Ebro basin (Iberian Peninsula). Among other factors, pollution could be responsible for these declines. We conducted, for the first time, acute toxicological tests (96 h) with heavy metals and ammonia on P. auricularius juveniles. The resulting LC50 values, in decreasing order of sensitivity, were: Cd = 38.85 µg/L, Cu = 58.64 µg/L, Ni = 124.60 µg/L, Zn = 267.40 µg/L, Cr(III) > 1000 µg/L, Pb > 2000 µg/L and total ammonia nitrogen (TAN) = 7.53 mg/L. We also report the estimated LC10, NOEC, LOEC and MATC values, which may be used to determine safer habitat conditions. Finally, we compare the obtained LC50 values with the concentrations of the toxicants in natural habitats where the species is present. Overall, the results reported here could be used to implement effective conservation actions, such as relocation of specimens to less-polluted sites or reduction of the concentration of pollutants in disturbed habitats. Considering the lack of ecotoxicological studies on freshwater mussels in Europe, this study may also be useful to establish toxicological reference limits for this imperiled faunal group.

中文翻译：

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Pseudunio auricularius 对金属和氨的敏感性：初步评估

极度濒危的淡水贻贝 Pseudunio auricularius (Spengler, 1793) 的种群数量急剧下降，尤其是在埃布罗盆地（伊比利亚半岛）。除其他因素外，污染可能是造成这些下降的原因。我们首次对耳形假单胞菌幼鱼进行了重金属和氨的急性毒理学试验（96 小时）。得到的 LC50 值（按灵敏度降序排列）为：Cd = 38.85 µg/L，Cu = 58.64 µg/L，Ni = 124.60 µg/L，Zn = 267.40 µg/L，Cr(III) > 1000 µg/L , Pb > 2000 µg/L 且总氨氮 (TAN) = 7.53 mg/L。我们还报告了估计的 LC10、NOEC、LOEC 和 MATC 值，这些值可用于确定更安全的栖息地条件。最后，我们将获得的 LC50 值与该物种存在的自然栖息地中的有毒物质浓度进行比较。总的来说，这里报告的结果可用于实施有效的保护行动，例如将标本迁移到污染较少的地点或减少受干扰栖息地的污染物浓度。考虑到欧洲缺乏对淡水贻贝的生态毒理学研究，这项研究也可能有助于为这个濒危动物群建立毒理学参考限值。