Yu Lin-peng, Fang Tao, Xiong Dao-wen, Zhu Wen-tao, Sima Xiao-feng
Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China.
J Environ Monit. 2011 Jul;13(7):1975-82. doi: 10.1039/c1em10197h. Epub 2011 May 24.
With the common application of nanoscale zinc oxide (nZnO) and significant potential for its release directly into aquatic environments, it is urgent to carry out research on ecotoxicological impact of nZnO. The characterization of nZnO, the amount of ˙OH in suspensions in the presence of light and the acute toxicity of nZnO and its bulk counterpart suspensions, as well as the acute toxicity of Zn(2+) solution to zebrafish (Danio rerio) at 96 h were studied. It was found that nZnO aggregated into irregular shapes in suspensions, and showed a relationship between its size distribution and concentration. In the presence of light, nZnO suspensions could generate ˙OH, the concentration of which increased with time. Although it was generally thought that ˙OH played a role in the biotoxicity to zebrafish, similar toxicity was observed for the nZnO and bulk ZnO suspensions (96 h LC(50) 3.969 mg L(-1), 2.525 mg L(-1), respectively). Furthermore, the sedimentation of nZnO and bulk ZnO in suspensions, and the accumulation of Zn in zebrafish were studied. The results showed that dissolved Zn(2+), from nZnO and bulk ZnO in suspensions, were toxic to zebrafish, while the aggregation and sedimentation of nZnO suspensions reduced the toxicity of nZnO. However, Zn(2+) may not be the main source of acute toxicity of nZnO and bulk ZnO to zebrafish. The experimental results highlight the importance of a systematic assessment of toxicity mechanisms of metal oxide nanoparticles (NPs) to determine definitively whether their toxicity is caused by nano-effects.
随着纳米氧化锌（nZnO）的广泛应用及其直接释放到水生环境中的巨大潜力，开展nZnO的生态毒理学影响研究迫在眉睫。研究了nZnO的表征、光照下悬浮液中˙OH的含量、nZnO及其本体对应物悬浮液的急性毒性，以及96小时时Zn(2+)溶液对斑马鱼（Danio rerio）的急性毒性。发现nZnO在悬浮液中聚集成不规则形状，且其尺寸分布与浓度之间存在关系。在光照下，nZnO悬浮液可产生˙OH，其浓度随时间增加。尽管一般认为˙OH对斑马鱼的生物毒性起作用，但nZnO和块状ZnO悬浮液观察到类似的毒性（96小时LC(50)分别为3.969 mg L(-1)、2.525 mg L(-1)）。此外，研究了nZnO和块状ZnO在悬浮液中的沉降以及Zn在斑马鱼体内的积累。结果表明，悬浮液中nZnO和块状ZnO溶解出的Zn(2+)对斑马鱼有毒，而nZnO悬浮液的聚集和沉降降低了nZnO的毒性。然而，Zn(2+)可能不是nZnO和块状ZnO对斑马鱼急性毒性的主要来源。实验结果突出了系统评估金属氧化物纳米颗粒（NPs）毒性机制以明确确定其毒性是否由纳米效应引起的重要性。
