Chen Xiaolin, O'Halloran John, Jansen Marcel A K
School of Biological, Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Field, North Mall, Cork, Ireland.
School of Biological, Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Field, North Mall, Cork, Ireland; Environmental Research Institute, University College Cork, Cork, Ireland.
Aquat Toxicol. 2016 May;174:46-53. doi: 10.1016/j.aquatox.2016.02.012. Epub 2016 Feb 20.
Nano-ZnO particles have been reported to be toxic to many aquatic organisms, although it is debated whether this is caused by nanoparticles per sé, or rather dissolved Zn. This study investigated the role of dissolved Zn in nano-ZnO toxicity to Lemna minor. The technical approach was based on modulating nano-ZnO dissolution by either modifying the pH of the growth medium and/or surface coating of nano-ZnO, and measuring resulting impacts on L. minor growth and physiology. Results show rapid and total dissolution of nano-ZnO in the medium (pH 4.5). Quantitatively similar toxic effects were found when L. minor was exposed to nano-ZnO or the "dissolved Zn equivalent of dissolved nano-ZnO". The conclusion that nano-ZnO toxicity is primarily caused by dissolved Zn was further supported by the observation that phytotoxicity was absent on medium with higher pH-values (>7), where dissolution of nano-ZnO almost ceased. Similarly, the reduced toxicity of coated nano-ZnO, which displays a slower Zn dissolution, is also consistent with a major role for dissolved Zn in nano-ZnO toxicity.
据报道，纳米氧化锌颗粒对许多水生生物有毒，不过对于这是由纳米颗粒本身还是溶解的锌所导致存在争议。本研究调查了溶解的锌在纳米氧化锌对浮萍毒性中的作用。技术方法是通过改变生长培养基的pH值和/或纳米氧化锌的表面涂层来调节纳米氧化锌的溶解，并测量对浮萍生长和生理的影响。结果表明纳米氧化锌在培养基（pH 4.5）中迅速完全溶解。当浮萍暴露于纳米氧化锌或“溶解的纳米氧化锌的溶解锌当量”时，发现了定量相似的毒性效应。纳米氧化锌毒性主要由溶解的锌引起这一结论，进一步得到了以下观察结果的支持：在较高pH值（>7）的培养基上没有植物毒性，此时纳米氧化锌的溶解几乎停止。同样，涂层纳米氧化锌毒性降低，其锌溶解较慢，这也与溶解的锌在纳米氧化锌毒性中起主要作用相一致。
