Castaldo Giovanni, Pillet Marion, Ameryckx Leen, Bervoets Lieven, Town Raewyn M, Blust Ronny, De Boeck Gudrun
Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Antwerp, Belgium.
Front Physiol. 2021 Mar 16;12:651584. doi: 10.3389/fphys.2021.651584. eCollection 2021.
The aquatic environment is the final sink of various pollutants including metals, which can pose a threat for aquatic organisms. Waterborne metal mixture toxicity might be influenced by environmental parameters such as the temperature. In the present study, common carp were exposed for 27 days to a ternary metal mixture of Cu, Zn, and Cd at two different temperatures, 10 and 20°C. The exposure concentrations represent 10% of the 96 h-LC (concentration lethal for the 50% of the population in 96 h) for each metal (nominal metal concentrations of Cu: 0.08 μM; Cd: 0.02 μM and Zn: 3 μM). Metal bioaccumulation and toxicity as well as changes in the gene expression of enzymes responsible for ionoregulation and induction of defensive responses were investigated. Furthermore the hepatosomatic index and condition factor were measured as crude indication of overall health and energy reserves. The obtained results showed a rapid Cu and Cd increase in the gills at both temperatures. Cadmium accumulation was higher at 20°C compared to 10°C, whereas Cu and Zn accumulation was not, suggesting that at 20°C, fish had more efficient depuration processes for Cu and Zn. Electrolyte (Ca, Mg, Na, and K) levels were analyzed in different tissues (gills, liver, brain, muscle) and in the remaining carcasses. However, no major electrolyte losses were observed. The toxic effect of the trace metal ion mixture on major ion uptake mechanisms may have been compensated by ion uptake from the food. Finally, the metal exposure triggered the upregulation of the metallothionein gene in the gills as defensive response for the organism. These results, show the ability of common carp to cope with these metal levels, at least under the condition used in this experiment.
水生环境是包括金属在内的各种污染物的最终归宿，这些污染物会对水生生物构成威胁。水中金属混合物的毒性可能会受到温度等环境参数的影响。在本研究中，将鲤鱼在10℃和20℃这两种不同温度下暴露于铜、锌和镉的三元金属混合物中27天。暴露浓度代表每种金属96小时半数致死浓度（96小时内导致50%种群死亡的浓度）的10%（铜的名义金属浓度：0.08μM；镉：0.02μM；锌：3μM）。研究了金属生物积累和毒性以及负责离子调节和防御反应诱导的酶的基因表达变化。此外，还测量了肝体指数和条件因子，作为整体健康和能量储备的粗略指标。所得结果表明，在两个温度下鳃中铜和镉的含量迅速增加。与10℃相比，20℃时镉的积累更高，而铜和锌的积累并非如此，这表明在20℃时，鱼类对铜和锌有更有效的净化过程。分析了不同组织（鳃、肝脏、大脑、肌肉）和剩余鱼体中的电解质（钙、镁、钠和钾）水平。然而，未观察到重大的电解质损失。痕量金属离子混合物对主要离子摄取机制的毒性作用可能已被从食物中摄取的离子所补偿。最后，金属暴露触发了鳃中金属硫蛋白基因的上调，作为生物体的防御反应。这些结果表明，鲤鱼至少在本实验所用条件下有能力应对这些金属水平。
