中文摘要：

以大型蜃为模式生物，研究了自然光照（光暗比为12h：12h）和黑暗条件下纳米ZnO对水生生物的急性毒性效应．实验结果表明，在自然光照条件下，不同粒径纳米ZnO对大型潘的毒性顺序为（25±5）和（10±1）〉（90±10）nm，其EC50分别为12．21，9．96和167．36mg／L；黑暗备件下，（10±1），（25±5）和（90±10）nm ZnO对大型潘抑制的EC50分别为19．64，206．70和409．84mg／L．由此可以看出，纳米ZnO在光照条件下对大型潘的影响大于黑暗条件，且粒径大小影响其毒性强弱．

英文摘要：

The ecotoxicity of nanoscale ZnO water suspensions for Daphnia magna was used as the testing organisms under both conditions of natural light and darkness was examined using a method developed based on the standard OECD guidelines for the testing of chemicals （i. e. OECD 201, 202）. The results showed that different nanoscale ZnO exhibited different toxicities to the testing organisms. The EC50 of （10±1）, （25±5） and （90±10） nm ZnO were 12. 21, 9. 96 and 167.36 mg/L in 48 hours under the natural light, respectively. Based on the results, their toxicity ranked as （25±5）, （10±1）〉（90±10） nm. The EC50 of （10±1）, （25±5） and （90±10） nm ZnO were 19.64, 206.70 and 409.84 mg/L in 48 hours under the darkness, respectively. The toxicity results indicated that nanoscale ZnO was more danger to daphnia magna in natural light than that of in darkness, and the toxicity was affected by nanoparticle size.