State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, Jiangsu Province 210093, China.
Environ Toxicol Chem. 2010 Dec;29(12):2814-22. doi: 10.1002/etc.340. Epub 2010 Oct 7.
It is now widely recognized that dissolution plays an important role in metallic nanoparticle toxicity, but to what extent remains unclear. In the present study, it was found that ZnO-engineered nanoparticle (ZnO-EN) toxicity to the marine diatom Thalassiosira pseudonana could be solely explained by zinc ion (Zn(2+) ) release. This is based on comparable inhibitive effects from ZnO-EN addition media, with or without the ultrafiltration through a 3-kD membrane, and from the media in which only Zn(2+) was added. Considering the importance of dissolution in ZnO-EN toxicity, Zn(2+) release kinetics was systematically examined under different conditions for the first time. It was found to be mainly influenced by pH as well as the specific surface area of the nanoparticles. In contrast, natural organic compounds either enhance or reduce Zn(2+) release, depending on their chemical composition and concentration. Compared with deionized water, ZnO-EN dissolution rates were accelerated in seawater, whereas ZnO-EN concentration itself only had a very small effect on Zn(2+) release. Therefore, dissolution as affected by several physicochemical factors should not be neglected in the effects, behavior, and fate of ENs in the environment.
现在人们普遍认识到，溶解在金属纳米颗粒毒性中起着重要作用，但在何种程度上仍不清楚。在本研究中，人们发现氧化锌工程纳米颗粒（ZnO-EN）对海洋硅藻假鱼腥藻的毒性可以仅仅通过锌离子（Zn(2+)）的释放来解释。这是基于 ZnO-EN 加标介质与超滤（通过 3kD 膜）与否、以及仅添加 Zn(2+)的介质具有相当的抑制效果。考虑到溶解在 ZnO-EN 毒性中的重要性，首次系统地研究了不同条件下的 Zn(2+)释放动力学。发现它主要受 pH 值和纳米颗粒的比表面积影响。相比之下，天然有机化合物会根据其化学组成和浓度，要么促进要么减少 Zn(2+)的释放。与去离子水相比，ZnO-EN 在海水中的溶解速度加快，而 ZnO-EN 浓度本身对 Zn(2+)的释放只有很小的影响。因此，在环境中 ENs 的影响、行为和归宿中，应考虑到受多种物理化学因素影响的溶解作用。
