低浓度微纳米氧化锌对中华圆田螺的生态毒性

为探讨微米氧化锌与纳米氧化锌对底栖生物生态毒性效应的影响,以中华圆田螺为受试生物,采用电子顺磁共振技术等多种检测方法,比较研究了肝脏自由基、抗氧化酶活性和丙二醛(MDA)含量在14 d暴露时间内的变化规律。研究发现:微、纳米氧化锌均可诱导中华圆田螺产生羟基(·OH)自由基;微米氧化锌暴露抑制SOD活性,纳米氧化锌则显著诱导SOD活性;纳米氧化锌对田螺肝脏羟基(·OH)自由基、CAT、MDA和Zn富集量的诱导程度高于微米氧化锌;微、纳米氧化锌均显著抑制GST活性,但两者之间差异不显著。结果表明,纳米氧化锌对中华圆田螺肝脏产生更强的毒性效应,但当微米氧化锌达到一定浓度后能够产生和纳米氧化锌相似水平的毒性。

Ecotoxicity of low concentration micro/nano ZnO exposure on 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.