Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium.
Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium.
Chemosphere. 2020 May;247:125942. doi: 10.1016/j.chemosphere.2020.125942. Epub 2020 Jan 17.
We have evaluated the interactive toxicity of Cu(II) and Cd(II) in water with different hardness levels using adult zebrafish (Danio rerio). Zebrafish were exposed to Cd(II) (0.2-22 μM) or Cu(II) (0.1-8 μM) in single or binary exposures in very soft, moderately hard or very hard water. The whole body burdens of Cd(II) and Cu(II) reflect the net effect of biouptake and elimination, mortality was the indicator of toxicity, and whole body major ion content was measured to assess ion regulatory functions. Cu(II) was found to be more toxic than Cd(II) for zebrafish, and Cu(II) and Cd(II) exhibited a significant synergistic effect. The toxicity of metal ions increased upon decreasing the ionic strength of the exposure medium, probably due to elevated competition between metal ions with other cations in hard water and increased activity of Ca pathways in soft water treatments. Whole body metal accumulation and the accumulation rate of both Cu and Cd increased as the metal ion concentration in the exposure medium increased. Nevertheless, neither parameter explained the observed synergistic effect on mortality. Finally, we observed a significant loss of whole body Na in fish which died during the metal exposure compared to surviving fish, irrespective of exposure conditions. Such an effect was not observed for other major cations (K, Ca and Mg). This observation suggests that, under the applied exposure conditions, survival was correlated to the capacity of the organism to maintain Na homeostasis.
我们使用成年斑马鱼（Danio rerio）评估了不同硬度水平的水中 Cu(II) 和 Cd(II) 的交互毒性。斑马鱼在极软、中等硬度或极硬水中单独或混合暴露于 Cd(II)（0.2-22 μM）或 Cu(II)（0.1-8 μM）中。Cd(II) 和 Cu(II) 的全身负荷反映了生物摄取和消除的净效应，死亡率是毒性的指标，全身主要离子含量用于评估离子调节功能。Cu(II) 对斑马鱼的毒性大于 Cd(II)，并且 Cu(II) 和 Cd(II) 表现出显著的协同作用。暴露介质的离子强度降低，金属离子的毒性增加，这可能是由于硬水中金属离子与其他阳离子之间的竞争加剧，以及软水处理中 Ca 途径的活性增加所致。随着暴露介质中金属离子浓度的增加，全身金属积累和 Cu 和 Cd 的积累率均增加。然而，没有任何参数可以解释对死亡率的观察到的协同效应。最后，我们观察到在金属暴露期间死亡的鱼与存活的鱼相比，全身 Na 大量损失，而与暴露条件无关。对于其他主要阳离子（K、Ca 和 Mg），未观察到这种影响。这种观察表明，在应用的暴露条件下，生存与生物体维持 Na 体内平衡的能力相关。
