Soucek David J, Dickinson Amy
Illinois Natural History Survey, Champaign, Illinois, USA.
Environ Toxicol Chem. 2015 Sep;34(9):2126-37. doi: 10.1002/etc.3038. Epub 2015 Aug 14.
Although insects occur in nearly all freshwater ecosystems, few sensitive insect models exist for use in determining the toxicity of contaminants. The objectives of the present study were to adapt previously developed culturing and toxicity testing methods for the mayfly Neocloeon triangulifer (Ephemeroptera: Baetidae), and to further develop a method for chronic toxicity tests spanning organism ages of less than 24 h post hatch to adult emergence, using a laboratory cultured diatom diet. The authors conducted 96-h fed acute tests and full-life chronic toxicity tests with sodium chloride, sodium nitrate, and sodium sulfate. The authors generated 96-h median lethal concentrations (LC50s) of 1062 mg Cl/L (mean of 3 tests), 179 mg N-NO3 /L, and 1227 mg SO4 /L. Acute to chronic ratios ranged from 2.1 to 6.4 for chloride, 2.5 to 5.1 for nitrate, and 2.3 to 8.5 for sulfate. The endpoints related to survival and development time were consistently the most sensitive in the tests. The chronic values generated for chloride were in the same range as those generated by others using natural foods. Furthermore, our weight-versus-fecundity plots were similar to those previously published using the food culturing method on which the present authors' method was based, indicating good potential for standardization. The authors believe that the continued use of this sensitive mayfly species in laboratory studies will help to close the gap in understanding between standard laboratory toxicity test results and field-based observations of community impairment.
尽管昆虫几乎存在于所有淡水生态系统中，但用于确定污染物毒性的敏感昆虫模型却很少。本研究的目的是调整先前开发的用于三角新蜉（Neocloeon triangulifer，蜉蝣目：短丝蜉科）的培养和毒性测试方法，并进一步开发一种慢性毒性测试方法，该方法涵盖从孵化后不到24小时到成虫羽化的整个生物体年龄阶段，使用实验室培养的硅藻作为食物。作者使用氯化钠、硝酸钠和硫酸钠进行了96小时喂食急性试验和全生命周期慢性毒性试验。作者得出96小时半数致死浓度（LC50）分别为1062 mg Cl/L（3次试验的平均值）、179 mg N-NO3 /L和1227 mg SO4 /L。氯化物的急性与慢性比值范围为2.1至6.4，硝酸盐为2.5至5.1，硫酸盐为2.3至8.5。在试验中，与生存和发育时间相关的终点始终是最敏感的。氯化物产生的慢性值与其他人使用天然食物得出的值在同一范围内。此外，我们的体重与繁殖力图与先前使用食物培养方法（本作者的方法基于该方法）发表的图相似，表明具有良好的标准化潜力。作者认为，在实验室研究中继续使用这种敏感的蜉蝣物种将有助于缩小标准实验室毒性测试结果与基于现场的群落损伤观察之间在理解上的差距。
