Smit C E, Van Gestel C A
Department of Ecology and Ecotoxicology, Vrije Universiteit, Amsterdam, The Netherlands.
Ecotoxicol Environ Saf. 1997 Aug;37(3):213-22. doi: 10.1006/eesa.1997.1558.
To generate reproducible and reliable results, most protocols for standardized toxicity tests prescribe strict limits for test conditions such as temperature and relative humidity. In the field, however, variability of climate can influence the functioning of organisms and induce changes in sensitivity. To evaluate the influence of temperature on the ecotoxicity of zinc, the springtail Folsomia candida was exposed to zinc-contaminated soil at different temperatures. In one experiment, the toxicity of ZnCl2 was determined at a constant temperature and under alternating temperature conditions. Although control performance of F. candida was influenced by the temperature treatment, effect concentrations for reproduction were not significantly different between treatments. Levels of internal zinc regulation were higher in animals exposed to alternating temperatures. Based on the observed influence of temperature on the accumulation of zinc, a second experiment was performed to determine the sensitivity of F. candida to zinc at four different exposure temperatures. A decrease in temperature led to an increase in sensitivity when sublethal parameters such as growth and reproduction were considered. However, animals were less sensitive at lower temperatures where mortality was concerned. Internal zinc concentrations in the animals increased with decreasing temperatures, and when the effect on reproduction was based on internal zinc levels, differences between temperature treatments were not significant. From the results of this study it is concluded that for F. candida, constant temperature conditions form a good basis for the extrapolation of toxicity levels to fluctuating temperature conditions. Since the average exposure temperature can alter the sensitivity of F. candida for zinc, and changes in sensitivity are parameter dependent, exposure temperature should be chosen carefully.
为了获得可重复和可靠的结果，大多数标准化毒性测试方案都对温度和相对湿度等测试条件规定了严格的限制。然而，在野外，气候的变化会影响生物的功能并导致敏感性的变化。为了评估温度对锌生态毒性的影响，将跳虫白符跳暴露于不同温度下受锌污染的土壤中。在一项实验中，在恒温及变温条件下测定了氯化锌的毒性。虽然白符跳的对照性能受温度处理的影响，但不同处理间繁殖的效应浓度没有显著差异。暴露于变温条件下的动物体内锌调节水平更高。基于观察到的温度对锌积累的影响，进行了第二项实验，以确定白符跳在四种不同暴露温度下对锌的敏感性。当考虑生长和繁殖等亚致死参数时，温度降低导致敏感性增加。然而，就死亡率而言，动物在较低温度下不太敏感。动物体内的锌浓度随温度降低而增加，并且当基于体内锌水平考虑对繁殖的影响时，温度处理间的差异不显著。从这项研究的结果可以得出结论，对白符跳来说，恒温条件为将毒性水平外推至波动温度条件提供了良好的基础。由于平均暴露温度会改变白符跳对锌的敏感性，且敏感性变化取决于参数，因此应谨慎选择暴露温度。
