The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam, Hong Kong, China.
Anal Bioanal Chem. 2010 Jan;396(2):609-18. doi: 10.1007/s00216-009-3249-z. Epub 2009 Nov 10.
Nano zinc oxide (nZnO) is increasingly used in sunscreen products, with high potential of being released directly into marine environments. This study primarily aimed to characterize the aggregate size and solubility of nZnO and bulk ZnO, and to assess their toxicities towards five selected marine organisms. Chemical characterization showed that nZnO formed larger aggregates in seawater than ZnO, while nZnO had a higher solubility in seawater (3.7 mg L(-1)) than that of ZnO (1.6 mg L(-1)). Acute tests were conducted using the marine diatoms Skeletonema costatum and Thalassiosia pseudonana, the crustaceans Tigriopus japonicus and Elasmopus rapax, and the medaka fish Oryzias melastigma. In general, nZnO was more toxic towards algae than ZnO, but relatively less toxic towards crustaceans and fish. The toxicity of nZnO could be mainly attributed to dissolved Zn(2+) ions. Furthermore, molecular biomarkers including superoxide dismutase (SOD), metallothionein (MT) and heat shock protein 70 (HSP70) were employed to assess the sublethal toxicities of the test chemicals to O. melastigma. Although SOD and MT expressions were not significantly increased in nZnO-treated medaka compared to the controls, exposure to ZnO caused a significant up-regulation of SOD and MT. HSP70 was increased two to fourfold in all treatments indicating that there were probably other forms of stress in additional to oxidative stress such as cellular injury.
纳米氧化锌（nZnO）越来越多地用于防晒霜产品，具有直接释放到海洋环境中的高潜力。本研究主要旨在表征 nZnO 和块状 ZnO 的聚集大小和溶解度，并评估它们对五种选定的海洋生物的毒性。化学特性表明，nZnO 在海水中形成的聚集体比 ZnO 大，而 nZnO 在海水中的溶解度（3.7mg/L）高于 ZnO（1.6mg/L）。急性试验使用海洋硅藻 Skeletoema costatum 和 Thalassiosia pseudonana、甲壳类动物 Tigriopus japonicus 和 Elasmopus rapax 以及青鳉鱼 Oryzias melastigma 进行。一般来说，nZnO 对藻类的毒性比 ZnO 强，但对甲壳类动物和鱼类的毒性相对较弱。nZnO 的毒性主要归因于溶解的 Zn(2+)离子。此外，还采用超氧化物歧化酶（SOD）、金属硫蛋白（MT）和热休克蛋白 70（HSP70）等分子生物标志物来评估测试化学品对 O. melastigma 的亚致死毒性。尽管与对照组相比，nZnO 处理的青鳉鱼中 SOD 和 MT 的表达没有显著增加，但 ZnO 的暴露导致 SOD 和 MT 的显著上调。所有处理组中的 HSP70 增加了两到四倍，这表明除了氧化应激之外，可能还有其他形式的应激，如细胞损伤。
