College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300350, China; School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China.
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300350, China.
Sci Total Environ. 2022 Jan 15;804:150228. doi: 10.1016/j.scitotenv.2021.150228. Epub 2021 Sep 9.
Silver nanoparticles (AgNPs) released into the environment are subject to environmental transformation processes before accumulating in aquatic organisms and transferring along the food chain. Lack of understanding on how environmental transformation affects trophic transfer of AgNPs hinders accurate prediction of the environmental risks of these widely present nanomaterials. Here we discover that pristine AgNPs as well as their sulfidation products (AgS-NPs) and dissolution products (Ag) tend to be accumulated in Daphnia magna and subsequently transferred to zebrafish. In D. magna, Ag exhibits the highest bioaccumulation potential whereas AgS-NPs show the lowest bioaccumulation. Surprisingly, the biomagnification factor of Ag along the D. magna-zebrafish food chain appears to be significantly lower relative to AgNPs and AgS-NPs, likely due to the limited release of Ag from D. magna to zebrafish during digestion. Moreover, AgNPs and their transformation products mainly accumulate in the internal organs, particularly intestine, of zebrafish. Adsorption of AgNPs on the surface of the intestinal cell membrane mitigates depuration of AgNPs and, at least in part, leads to the larger biomagnification factor of AgNPs, relative to their transformation products. This research highlights the necessity of considering environmental transformation processes of nanomaterials in assessing their bioavailability and risk.
银纳米颗粒（AgNPs）释放到环境中后，会在积累到水生生物并沿食物链转移之前经历环境转化过程。由于缺乏对环境转化如何影响 AgNPs 营养转移的理解，因此难以准确预测这些广泛存在的纳米材料的环境风险。在这里，我们发现原始 AgNPs 及其硫化产物（AgS-NPs）和溶解产物（Ag）倾向于在大型溞（Daphnia magna）中积累，并随后转移到斑马鱼中。在大型溞中，Ag 表现出最高的生物累积潜力，而 AgS-NPs 的生物累积最低。令人惊讶的是，Ag 沿大型溞-斑马鱼食物链的生物放大因子似乎明显低于 AgNPs 和 AgS-NPs，这可能是由于在消化过程中，Ag 从大型溞向斑马鱼的释放受到限制。此外，AgNPs 及其转化产物主要积累在斑马鱼的内脏器官中，特别是肠道中。AgNPs 吸附在肠细胞膜表面，减轻了 AgNPs 的净化，至少部分导致了 AgNPs 相对于其转化产物更大的生物放大因子。这项研究强调了在评估纳米材料的生物可利用性和风险时，必须考虑纳米材料的环境转化过程。
