中文摘要：

采用急性毒性实验方法,研究了水环境中常见重金属离子Cd2＋,Zn2＋和Cu2＋对介形类Physocypria kraepelini的急性毒性作用。实验过程按等差数间距设置6个Cd2＋浓度梯度,按等比数间距设置9个Zn2＋和9个Cu2＋浓度梯度。结果表明：24、48、72和96h时Cd2＋,Zn2＋和Cu2＋对P.kraepelini的半致死浓度（LC50）分别为1.37、0.39、0.21和0.04mg/l,217.27、34.36、23.77和8.42mg/l,及7.28、1.26、0.65和0.39mg/l。通过比较发现,P.kraepelini可以作为水体受Cd2＋污染的判别生物;P.kraepelini对Cd2＋,Zn2＋和Cu2＋的安全浓度分别为0.004、0.842和0.039mg/l,接近国家渔业水质标准（GB11607-89）规定的限值,因此其还可以作为渔业用水的判别生物。

英文摘要：

The acute toxicity test method was used to investigate the common heavy metal contaminations（Cd 2＋,Zn 2＋ and Cu 2＋）in water environment on Physocypria kraepelini.Experiment was assigned to arrange six Cd 2＋ concentration gradients according to arithmetic series,and to arrange nine Zn 2＋ and nine Cu 2＋ concentration gradients according to geometric series.The results indicated that the median lethal concentrations（LC_ 50）respectively were 1.37,0.39,0.21 and 0.04 mg/l of Cd 2＋,and 217.27,34.36,23.77 and 8.42 mg/l of Zn 2＋,and 7.28,1.26,0.65 and 0.39 mg/l of Cu 2＋ to P.kraepelini for 24 h,48 h,72 h and 96 h.By comparison,P.kraepelini could serve as a biological indicator of water contaminated by Cd 2＋.The safe concentrations（SC）of Cd 2＋,Zn 2＋ and Cu 2＋ to P.kraepelini were 0.004,0.842 and 0.039 mg/l respectively,which were close to the national water quality standard for fisheries（GB11607-89）,so P.kraepelini could be used for the evaluation of fishery water.