毒死蜱对淡水原生动物群落的急性毒性

Acute Toxicity of Chlorpyrifos to Freshwater Protozoa Community

以PFU法采集淡水中原生动物群落为试验对象对毒死蜱急性毒性进行研究。结果表明,毒死蜱对原生动物群落的48h-LC50为8.54mg·L-1,原生动物群落结构参数和功能参数随毒死蜱的加入量的增加而变化,植鞭毛虫种类数减少,优势种均为B类原生动物。以单种生物为试验对象对农药毒性的评价缺少环境真实性,而用微型生物群落则更接近自然环境,更有现实意义。

The toxicity of chemicals with bio-community has much a dv antage over th at with single organism.PFU(Polyurethane FoamUnit)can be used to collect microorganism s fromnatural water,and the predomi nant component in the PFUis protozoa,which includes the autotrophic and hetero trophic species.T here is predator-prey relationship between these pro tozoa,so it has the stru cture and function of community.The acute toxicity of chlorpyrifos to protozoa community colleted by PFU from freshwater was studied in this paper.The results sh owed that the 48h-LC 5 ,LC 20 and LC 50 of chlorpyrifos to the protozoa comm unity was 0.51mg ·L-1 ,2.19mg ·L-1 ,and 8.54mg ·L-1 respectively,which implied that organisms in community level have high toxi city resistance to chemicals.The structure parameter and function parameter of protozo a community changed with the changes of the concentration of chlorpyrifo s,the high concentration of chlorpyrifos corresponding with the simple structur e of protozoa community.When the con-centration of chlorpyrifos rose,th e spe cies of phytomastigophorea red uced and all the dominant species belonged to Bac tivoresde-trivores group.The evaluation of to xicity of pesticide from microbi ota community showed more environmenta l factuality and more practicable purport than that from s ingle species.