速灭威对花翅摇蚊幼虫的毒性效应

Toxic Effect of Metolcarb on Chironomus Kiiensis Larva

以花翅摇蚊为受试生物,在室内研究了氨基甲酸酯类杀虫剂速灭威对淡水底栖生物的急慢性毒性效应。急性毒性试验结果表明,在加标水中速灭威对摇蚊一龄幼虫24 h-EC_(50)、48 h-EC_(50)分别为4.52 mg/L、3.14 mg/L,对四龄幼虫24 h-EC_(50)、48 h-EC_(50)分别为12.24 mg/L、8.18 mg/L,一龄摇蚊幼虫对速灭威的敏感性高于四龄摇蚊幼虫。在慢性毒性试验中,加标上覆水法速灭威对摇蚊幼虫的羽化率半数效应浓度(EC_(50))及化蛹率半数效应浓度(EC_(50))分别为3.63 mg/L和3.72 mg/L,加标沉积物法速灭威对摇蚊幼虫的羽化率半数效应浓度(EC_(50))及化蛹率半数效应浓度(EC_(50))分别为20.60 mg/kg和23.71 mg/kg;随着速灭威处理浓度的升高,摇蚊幼虫的羽化率及化蛹率降低,羽化用时延长,沉积物表面筑巢行为明显加强;速灭威处理浓度与羽化摇蚊的性别比无显著相关性。

The acute and chronic toxic effects of the carbamate insecticide metolcarb on freshwater benthic organisms were studied in the laboratory using Chironomus kiiensis as the test organism.The results of the acute toxicity test showed that the 24 h-EC_(50)and 48 h-EC_(50)for the first instar larvae were 4.52 mg/L and 3.14 mg/L respectively,and for the fourth instar larvae were 12.24 mg/L and 8.18 mg/L respectively,indicating that the first instar larva of Chironomus kiiensis were more sensitive to metolcarb than the fourth instar larva.In the chronic toxicity test,the EC_(50)values of metolcarb in the spiked overlying water on the eclosion rate and pupation rate of the Chironomus kiiensis larva were 3.63 mg/L and 3.72 mg/L,respectively,and the EC_(50)values of metolcarb in the spiked sediment on the eclosion rate and pupation rate of the Chironomus kiiensis larva were 20.60 mg/kg and 23.71 mg/kg,respectively.With the increasing concentration of metolcarb,the eclosion rate and pupation rate of Chironomus kiiensis larva decreased,the eclosion time increased,and the nesting behavior on the sediment surface was significantly improved.There was no significant correlation between the concentration of metolcarb treatment and the sex ratio of eclosion Chironomus kiiensis.