Morley N J, Crane M, Lewis J W
School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 OEX, UK.
Int J Parasitol. 2001 Sep;31(11):1211-7. doi: 10.1016/s0020-7519(01)00229-6.
The toxicity of cadmium and zinc at concentrations ranging from 0.1 to 10000 microg/l was investigated with cercariae of Diplostomum spathaceum at three temperatures (12, 20, 25 degrees C) and three levels of water hardness (distilled water, soft water, hard water). Under most environmental conditions survival of cercariae was reduced by increasing metal concentration. Increasing water hardness and decreasing water temperature caused an increase in the survival of both control and metal exposed cercariae. However, with decreasing temperature increased survival of metal-exposed cercariae above the control occurred at a number of low metal concentrations. Differences in the relative toxicity of cadmium and zinc to cercariae was dependent on the environmental conditions of exposure. The two heavy metals demonstrated little toxicity to cercariae during the period of maximum cercarial infectivity (0-5 h). The mechanisms of metal toxicity and their effects on cercarial survival are discussed.
在三种温度（12、20、25摄氏度）和三种水硬度水平（蒸馏水、软水、硬水）下，用剑带双穴吸虫尾蚴研究了浓度范围为0.1至10000微克/升的镉和锌的毒性。在大多数环境条件下，尾蚴的存活率会随着金属浓度的增加而降低。水硬度增加和水温降低会导致对照尾蚴和暴露于金属的尾蚴的存活率均增加。然而，随着温度降低，在一些低金属浓度下，暴露于金属的尾蚴存活率高于对照。镉和锌对尾蚴的相对毒性差异取决于暴露的环境条件。在尾蚴最大感染性期间（0 - 5小时），这两种重金属对尾蚴几乎没有毒性。讨论了金属毒性机制及其对尾蚴存活的影响。
