中文摘要：

采用＂OECD化学品测试准则＂和＂化学农药环境安全评价试验准则＂方法,选择无脊椎动物大型蚤Daphnia magna为受试生物,以手性α-HCH、o.p′-DDT外消旋体及其对映体作为目标污染物,在环境相关浓度下,对大型蚤进行急慢性毒性研究.结果表明,两种手性有机氯杀虫剂对大型蚤急慢性毒性均表现出显著的对映体选择性差异.α-HCH外消旋体及其（＋）-α-HCH和（-）-α-HCH对D.magna的48h-LC50值分别为1.47,1.12和1.98mg/L;o.p′-DDT外消旋体及其（＋）-o.p′-DDT和（-）-o.p′-DDT对D.magna的48h-LC50值分别为0.27,0.52和0.18mg/L.慢性毒性实验表明,（＋）-α-HCH在质量浓度大于10μg/L时对大型蚤的体长造成显著的抑制作用;α-HCH外消旋体及其（＋）-α-HCH在质量浓度大于10μg/L时对大型蚤的内禀增长率造成显著的影响.

英文摘要：

Using OECD guidelines for testing of chemicals and chemical pesticide environmental safety assessment testing criteria, choosing Daphnia magna as the tested organism, this thesis evaluated acute and chronic toxicity of racemate and enantiomers of α-HCH and o. pt-DDT to Daphnia magna. The results showed that enantio-selectivity was observed for acute and chronic toxicity of two chiral OCPs to D. magna. The 48 h-LC50of rac-α-HCH, （＋）-α-HCH and （-）-α-HCH to D. magna were 1.47, 1.12 and 1.98 mg/L, respectively. And 48 h-LC50of rac-o, p＇-DDT, （4-）-0. p＇-DDT and （-）-o. p,- DDT to D. magna were 0.27, 0.52 and 0.18 mg/L, respectively. The results of chronic toxicity showed that parameters such as length was significantly affected at （＋）-α-HCH concentration higher than 10μg/L, rac-a-HCH and （＋）-α-HCH of 10 μg/L significantly prolonged the intrinsic rate of natural increase （r）.