Cong Yi, Jin Fei, Wang Juying, Mu Jingli
Key Laboratory for Ecological Environment in Coastal Areas, State Oceanic Administration, Dalian 116023, Liaoning Province, China; Division of Marine Chemistry, National Marine Environmental Monitoring Center, Dalian 116023, Liaoning Province, China.
Aquat Toxicol. 2017 Apr;185:11-18. doi: 10.1016/j.aquatox.2017.01.006. Epub 2017 Jan 19.
The negative effects of metal oxide nanoparticles on aquatic environment and organisms have caused much concern. In this study, the embryotoxicity of zinc oxide nanoparticles (ZnO NP) to marine medaka, Oryzias melastigma, was explored and compared with that of aqueous Zn (ZnSO·7HO). The Zn released from ZnO NP in artificial seawater at exposure concentrations was also measured. Results showed that zinc ion release percentage (%) decreased with increasing concentration, which was 44%, 41% and 25% at 0.1, 1 and 10mg/L of ZnO NP suspension, respectively. After 20 d exposure of medaka embryos to ZnO NP, we observed increased mortality and heart rate, reduced percent total hatching success, delayed hatching of embryos and increased malformation% of newly-hatched larvae in ZnO NP treatment compared to the control group. Furthermore, ZnO NPs have significantly greater effects than the aqueous Zn for mortality and heart rate, indicating that ZnO NPs themselves, in particulate or aggregate form, contribute to the observed toxicity. Edema was the most commonly found malformation in newly-hatched larvae after ZnO NP exposure. Overall, our findings suggest that the embryonic stage of marine medaka is sensitive to ZnO NP exposure. Studies of the toxic mechanism of ZnO NPs should not ignore the impact of NPs since the greater effects of ZnO NPs than of aqueous Zn ions observed in this study cannot be explained by the ZnO NP dissolution. The ion release profile of ZnO NPs in marine environment is related to both NP and seawater characteristics, which should be analyzed on a case-by-case basis. The ZnO NP-related Zn speciation may play an important role in the dissolution and toxicity processes of ZnO NPs in marine environment, and further speciation study may contribute to the interpretation of ZnO NP toxicity.
金属氧化物纳米颗粒对水生环境和生物的负面影响已引起广泛关注。本研究探讨了氧化锌纳米颗粒（ZnO NP）对海洋青鳉（Oryzias melastigma）的胚胎毒性，并与水相锌（ZnSO₄·7H₂O）进行了比较。同时还测定了暴露浓度下人工海水中ZnO NP释放的锌。结果表明，锌离子释放百分比（%）随浓度增加而降低，在0.1、1和10mg/L的ZnO NP悬浮液中分别为44%、41%和25%。将青鳉胚胎暴露于ZnO NP 20天后，与对照组相比，我们观察到ZnO NP处理组的死亡率和心率增加、总孵化成功率降低、胚胎孵化延迟以及新孵化幼虫的畸形率增加。此外，ZnO NPs对死亡率和心率的影响明显大于水相锌，这表明ZnO NPs本身，以颗粒或聚集体形式，导致了所观察到的毒性。水肿是ZnO NP暴露后新孵化幼虫中最常见的畸形。总体而言，我们的研究结果表明海洋青鳉的胚胎阶段对ZnO NP暴露敏感。由于本研究中观察到的ZnO NPs比水相锌离子的影响更大，无法通过ZnO NP的溶解来解释，因此对ZnO NPs毒性机制的研究不应忽视纳米颗粒的影响。ZnO NPs在海洋环境中的离子释放情况与纳米颗粒和海水特性有关，应逐案分析。ZnO NP相关的锌形态可能在ZnO NPs在海洋环境中的溶解和毒性过程中起重要作用，进一步的形态研究可能有助于解释ZnO NP的毒性。
