2种杀虫剂对日本沼虾的急性毒性

Acute Toxicity of Two Pesticides to Macrobrachium nipponense

研究了毒死蜱和硫丹对日本沼虾(Macrobrachium nipponense)的毒性作用。根据预试验确定2种杀虫剂对日本沼虾的急性毒性试验浓度,测定沼虾24和48 h的半致死浓度ρ(LC50),在0～48 h的ρ(LC50)值范围内设定6个浓度梯度,对日本沼虾进行24 h胁迫试验以测定耗氧量和排氨量。毒死蜱和硫丹对日本沼虾的24和48 hρ(LC50)分别为5.03、2.01和8.47、4.02μg·L-1,其安全质量浓度分别为0.096和0.272μg·L-1,表明日本沼虾对毒死蜱的敏感性明显高于硫丹。随着2种杀虫剂浓度的逐渐升高,日本沼虾的耗氧量和排氨量均呈现下降趋势,表明日本沼虾采用相同的适应方式来抵御2种杀虫剂对其基础代谢的胁迫,表现为被动的忍耐。

Toxic effects of chlorpyrifos and endosulfan on Macrobrachium nipponense,a kind of freshwater shrimp,were investigated for the first time.Firstly,acute toxicity tests of chlorpyrifos and endosulfan were conducted,separately,to determine 24 and 48 h ρ（LCs0） of the insecticides to the shrimps.In the tests,six treatments were set up within the range of 0-48 h p（LC50）,and the shrimps were kept exposed for 24 h for determination of their oxygen consumption and ammonia excretion.It was found that the 24 and 48 h p（LC50） was 5.03 and 2.01 μg · L-1,respectively,for chlorpyrifos and 8.47 and 4.02 μg · L-1,respectively,for endosulfan,and their safe concentration was 0.096 and 0.272 μg · L-1,respectively,suggesting that the shrimps are more sensitive to chlorpyrifos than to endosulfan.With the increasing concentrations of the two insecticides,both the oxygen consumption and ammonia excretion of the shrimps decreased in volume,indicating that the shrimps use the same mode of adaptability to protect their basic metabolism against the stress of the two insecticides,that is to say,passive endurance.