Ecotoxicity of low concentration micro/nano ZnO exposure on Cipangopaludina Cahayensis

LIU Hui;JIANG An-qi;WANG Wei-mu;College of Water Conservancy and Hydropower, Hohai University;Key Laboratory of High-Efficient Irrigation and Drainage and Agricultural Water and Soil Environment in Southern China, Ministry Education;

micro ZnO;;nano ZnO;;free radicals;;antioxidant system;;Cipangopaludina Cahayensis

Cipangopaludina Cahayensis was chosen as a test species to investigate the effects of micro and nano ZnO. The free radicals generation was determined by EPR and several antioxidant enzyme such as SOD, CAT, MDA, GST were measured. The study found that, micro/nano ZnO could both induce the production of hydroxyl free radicals(·OH)in Cipangopaludina Cahayensis. The intensity of free radical,bioaccumulation of Zn under nano ZnO exposure were higher than micro ZnO exposure. SOD activities were inhibited under micro ZnO except 1~2 mg·L~(-1), and were significantly induced under nano ZnO exposure. Micro/nano ZnO exposure induced the CAT activities and activities were higher with nano ZnO exposure. Furthermore, nano ZnO and 1~2 mg·L~(-1)micro ZnO induced the synthesis of MDA, suggested that more severe oxidative stress were caused by nano ZnO under the same concentration. However, the inhibition of GST activity was both significantly under micro/nano ZnO exposure and there was no obvious difference between them. The results showed that nano ZnO resulted in greater toxic effects on Cipangopaludina Cahayensis, and that higher micro ZnO could produce a similar toxicity to a lower concentration of nano ZnO.