Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
Water Science and Technology Directorate, Environment and Climate Change Canada, Burlington, Ontario, Canada.
Environ Toxicol Chem. 2020 Nov;39(11):2221-2227. doi: 10.1002/etc.4840. Epub 2020 Sep 16.
Effects-directed analysis (EDA) is used to identify the principal toxic components within a complex mixture using iterative steps of chemical fractionation guided by bioassay results. Bioassay selection can be limited in EDA because of the volume requirements for many standardized test methods, and therefore, a reduced-volume acute toxicity test that also provides whole-organism responses is beneficial. To address this need, a static, 7-d, water-only, reduced-volume method (50 mL, 10 organisms) was developed for Hyalella azteca that substantially decreases the volume requirements of standard-volume acute test exposures (200-500 mL of test solution, 15-20 organisms) while maintaining water quality and meeting control survival criteria. Standard- and reduced-volume methods were compared by conducting concurrent toxicity tests with 2 inorganic toxicants (KCl and CdCl ) and 2 organic mixtures of naphthenic acid fraction components (NAFCs) to evaluate test performance. There was no difference between methods when comparing the median lethal concentrations (LC50s) for KCl and both NAFC mixtures (p > 0.05). The LC50s for CdCl were statistically different (p = 0.0002); however, this was not considered biologically meaningful because the difference between LC50s was <2-fold. In conclusion, the reduced-volume H. azteca test method generated results comparable to standard-volume test methods and is suitable for use in situations where limited testing material is available, such as when conducting EDA. Environ Toxicol Chem 2020;39:2221-2227. © Her Majesty the Queen in Right of Canada 2020. Reproduced with the permission of the Minister of Environment and Climate Change Canada.
效应导向分析（EDA）用于使用生物测定结果指导的化学分馏迭代步骤来识别复杂混合物中的主要有毒成分。由于许多标准化测试方法的体积要求，EDA 中的生物测定选择可能会受到限制，因此，需要一种提供整体生物反应的体积减少的急性毒性测试。为了解决这一需求，开发了一种静态的、为期 7 天的、仅用水的、体积减少的 Hyalella azteca 方法（50 毫升，10 个生物），该方法大大减少了标准体积急性测试暴露（200-500 毫升测试溶液，15-20 个生物）的体积要求，同时保持水质并符合对照生存标准。通过同时进行 2 种无机毒物（KCl 和 CdCl ）和 2 种萘酸馏分成分（NAFCs）的有机混合物的毒性测试，比较了标准体积和减少体积方法，以评估测试性能。在比较 KCl 和两种 NAFC 混合物的中位致死浓度（LC50）时，两种方法之间没有差异（p>0.05）。CdCl 的 LC50 统计上有差异（p=0.0002）；然而，这被认为没有生物学意义，因为 LC50 之间的差异<2 倍。总之，减少体积的 H. azteca 测试方法产生的结果与标准体积测试方法相当，适用于可用测试材料有限的情况，例如进行 EDA 时。环境毒理化学 2020；39：2221-2227。©加拿大女王陛下以其在加拿大的权利名义 2020 年。经加拿大环境与气候变化部部长许可转载。
