CESAM and Department of Biology, University of Aveiro, Campus Santiago, 3810-193, Aveiro, Portugal.
Environ Sci Pollut Res Int. 2010 Jul;17(6):1217-29. doi: 10.1007/s11356-010-0298-y. Epub 2010 Feb 20.
Global warming has become a source of awareness regarding the potential deleterious effects of extreme abiotic factors (e.g., temperature, dissolved oxygen (DO) levels) and also their influence on chemicals toxicity. In this work, we studied the combined effects of nickel and temperature (low and high levels) and nickel and low levels of DO to Daphnia magna, and concentration addition and independent action concepts as well as their deviations for synergism/antagonism, dose ratio and dose level dependency, were applied to survival and feeding rate data. Nickel single exposure showed an LC(50) value for 48 h of 7.36 mg l(-1) and an EC(50) value for feeding impairment at 2.41 mg l(-1). In the acute exposures to high and low temperatures, 50% of mortality was observed, respectively, at 30.7 degrees C and 4.2 degrees C whereas 50% reduction on the feeding activity was recorded at 22.6 degrees C and 16.0 degrees C. Relatively to low DO levels, a LC(50) value for 48 h of 0.5 mg l(-1) was obtained; feeding activity EC(50) value was 2 mg l(-1). On acute combined experiments, antagonism was observed for the combination of nickel and extreme temperatures, whereas a synergistic behaviour was observed in the combined exposure of nickel and low DO levels. At sublethal levels, nickel showed to be the main inducer of toxicity at high and low temperatures but not at low levels of dissolved oxygen. Toxicokinetics and toxicodynamics modelling studies should be made in the future to understand the toxicological pathways involved on complex combinations of stressors and to validate any conclusions.
全球变暖已经引起了人们对极端非生物因素（如温度、溶解氧（DO）水平）潜在有害影响的关注，同时也关注了这些因素对化学物质毒性的影响。在这项工作中，我们研究了镍和温度（高低水平）以及镍和低 DO 水平对大型蚤的联合影响，并应用浓度加和独立作用概念及其对协同/拮抗作用、剂量比和剂量水平依赖性的偏差，来分析生存和摄食率数据。镍的单一暴露显示出 48 小时的 LC(50)值为 7.36mg l(-1)，摄食损伤的 EC(50)值为 2.41mg l(-1)。在急性高温和低温暴露中，分别在 30.7°C 和 4.2°C 时观察到 50%的死亡率，而在 22.6°C 和 16.0°C 时记录到 50%的摄食活性降低。相对于低 DO 水平，镍的 48 小时 LC(50)值为 0.5mg l(-1)；摄食活性 EC(50)值为 2mg l(-1)。在急性联合实验中，镍与极端温度的联合作用表现出拮抗作用，而镍与低 DO 水平的联合暴露则表现出协同作用。在亚致死水平下，镍在高温和低温下是主要的毒性诱导剂，但在低 DO 水平下则不是。未来应该进行毒代动力学和毒动学模型研究，以了解复杂胁迫组合相关的毒性途径，并验证任何结论。
