Department of Biology, Biotechnical Faculty, University of Ljubljana, 111, Jamnikarjeva 101,1000 Ljubljana, Slovenia.
Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana, Slovenia.
Ecotoxicol Environ Saf. 2018 May 15;152:61-66. doi: 10.1016/j.ecoenv.2018.01.007. Epub 2018 Feb 4.
One of the most widely used aquatic standarized tests for the toxicity screening of chemicals is the acute toxicity test with the freshwater crustacean Daphnia magna, which has also been applied in the toxicity screening of manufactured nanoparticles (NPs). However, in the case of non-soluble NPs most of the results of this test have showed no effect. The aim of the work presented here was to modify the standardized test by the least possible extent to make it more sensitive for non-soluble particles. The standard acute immobilisation assay with daphnids was modified by prolonging the exposure period and by measuring additional endpoints. Daphnids were exposed to TiO NPs in a standard acute test (48h of exposure), a standard acute test (48h of exposure) followed by 24h recovery period in clean medium or a prolonged exposure in the NPs solutions totaling 72h. Together with immobility, the adsorption of NPs to body surfaces was also observed as an alternative measure of the NPs effects. Our results showed almost no effect of TiO NPs on D. magna after the 48h standard acute test, while immobility was increased when the exposure period to TiO NPs was prolonged from 48h to 72h. Even when daphnids were transferred to clean medium for additional 24h after 48h of exposure to TiO NPs the immobility increased. We conclude that by transferring the daphnids to clean medium at the end of the 48h exposure to TiO NPs, the delayed effects of the tested material can be seen. This methodological step could improve the sensitivity of D. magna test as a model in nanomaterial environmental risk assessment.
最常用于筛选化学品毒性的水生标准化测试之一是使用淡水甲壳类动物大型溞（Daphnia magna）的急性毒性测试，该测试也已应用于制造纳米颗粒（NPs）的毒性筛选。然而，在不溶性 NPs 的情况下，该测试的大多数结果均未显示出效果。本研究的目的是通过尽可能少的修改标准化测试来提高其对不溶性颗粒的敏感性。通过延长暴露时间和测量其他终点，对带有溞类的标准急性固定化测定法进行了修改。将溞类暴露于 TiO NPs 中，进行标准急性测试（48 小时暴露），标准急性测试（48 小时暴露），然后在清洁介质中恢复 24 小时，或者在 NPs 溶液中延长暴露时间，总计 72 小时。与不动性一起，还观察到 NPs 吸附到身体表面，作为 NPs 效应的替代测量方法。我们的结果表明，在 48 小时标准急性测试后，TiO NPs 对 D. magna 的影响几乎可以忽略不计，而当将 TiO NPs 的暴露时间从 48 小时延长至 72 小时时，不动性增加。即使在 48 小时暴露于 TiO NPs 后将溞类转移到清洁介质中 24 小时，不动性也会增加。我们得出的结论是，通过在 48 小时暴露于 TiO NPs 结束时将溞类转移到清洁介质中，可以观察到测试材料的延迟效应。此方法步骤可以提高 D. magna 测试作为纳米材料环境风险评估模型的敏感性。
