Idaho Water Science Center, US Geological Survey, Boise, Idaho.
Columbia Environmental Research Center, US Geological Survey, Columbia, Missouri.
Environ Toxicol Chem. 2021 Sep;40(9):2484-2498. doi: 10.1002/etc.5131. Epub 2021 Jul 20.
The potential for delayed mortality following short-term episodic pollution events was evaluated by exposing cladocerans (Ceriodaphnia dubia) and rainbow trout (Oncorhynchus mykiss) to zinc (Zn) in various 1- to 48-h and 1- to 96-h exposures, respectively, followed by transferring the exposed organisms to clean water for up to 47 h for C. dubia and up to 95 h for trout for additional observation. For C. dubia, 1-h exposures of up to 3790 µg Zn/L never resulted in mortality during the actual Zn exposures, but by 48 h, a 1-h exposure to 114 µg/L, a concentration similar to the present US national water quality acute criterion for the test water conditions, ultimately killed 70% of C. dubia. With C. dubia, the speed of action of Zn toxicity was faster for intermediate concentrations than for the highest concentrations tested. For rainbow trout, pronounced delayed mortalities by 96 h only occurred following ≥8-h exposures. For both species, ultimate mortalities from Zn exposures ≤8 h mostly presented as delayed mortalities, whereas for exposures ≥24 h, almost all ultimate mortalities presented during the actual exposure periods. With Zn, risks of delayed mortality following exposures to all concentrations tested were much greater for the more sensitive, small-bodied invertebrate (C. dubia) than for the less sensitive, larger-bodied fish (rainbow trout). These results, along with previous studies, show that delayed mortality is an important consideration in evaluating risks to aquatic organisms from brief, episodic exposures to some substances. Environ Toxicol Chem 2021;40:2484-2498. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
评估了短期偶发性污染事件后延迟死亡的可能性，方法是分别将枝角类（Ceriodaphnia dubia）和虹鳟（Oncorhynchus mykiss）暴露于锌（Zn）中，暴露时间分别为 1 至 48 小时和 1 至 96 小时，然后将暴露的生物转移到清洁水中，枝角类最多 47 小时，虹鳟最多 95 小时，以便进行进一步观察。对于 C. dubia，在实际的 Zn 暴露中，1 小时内暴露于高达 3790μg/L 的 Zn 从未导致死亡，但在 48 小时时，暴露于 114μg/L 的 1 小时暴露，浓度类似于目前测试用水条件下美国国家水质急性标准，最终导致 70%的 C. dubia死亡。对于 C. dubia，Zn 毒性的作用速度对于中间浓度比测试的最高浓度更快。对于虹鳟，仅在 ≥8 小时暴露后才出现明显的延迟死亡。对于这两个物种，在 Zn 暴露 ≤8 小时的情况下，最终死亡率大多表现为延迟死亡率，而在暴露时间 ≥24 小时的情况下，几乎所有的最终死亡率都发生在实际暴露期间。对于 Zn，在测试的所有浓度下，暴露后延迟死亡率的风险对于更敏感、体型较小的无脊椎动物（C. dubia）远大于不那么敏感、体型较大的鱼类（虹鳟）。这些结果以及以前的研究表明，延迟死亡是评估水生生物短暂偶发性暴露于某些物质风险的一个重要考虑因素。环境毒理化学 2021；40:2484-2498。©2021 作者。环境毒理化学由 Wiley Periodicals LLC 代表 SETAC 出版。本文由美国政府雇员做出贡献，其工作在美国属于公有领域。
