杀虫剂西维因对萼花臂尾轮虫急性毒性和生活史参数的影响

Effects of Carbaryl on Acute Toxicity and Life Cycle Parameters of Brachionus calyciflorus

采用生态毒理学方法,研究了(25±1)℃下,杀虫剂西维因对萼花臂尾轮虫的急性毒性影响以及慢性染毒对轮虫生命史参数的影响。结果表明:西维因对轮虫24 h急性毒性半致死浓度为4.868 mg·L-1,95%置信区间为4.538~5.229 mg·L-1;慢性毒性实验结果显示,除产卵量外,西维因对轮虫的主要发育阶段历时、平均寿命、净生殖率、生命期望、内禀增长率以及世代时间均有显著影响(P<0.05)。与对照组相比,西维因显著降低(缩短)轮虫平均寿命、净生殖率和内禀增长率,且高浓度的西维因对平均寿命和内禀增长率的影响更为显著;幼体阶段历时和胚胎发育时间均随西维因浓度的升高而延长;除2.2 mg·L-1的西维因对轮虫世代时间无显著影响外,其他各浓度均显著缩短轮虫世代时间(P<0.05)。

Carbaryl(C12H11NO2), a carbamate insecticide, has been used worldwidely since 1956. Previous studies have been focused on mammals, amphibians, and fishes. However, little information was available on rotifers. In this study, we used freshwater rotifer, Brachionus calyciflorus, as a model species, which is distributed widely in lakes, rivers, and ponds, to examine the ecotoxicity of carbaryl on small aquatic animals. Rotifer was originally collected from South Lake, Wuhan in 2013, and cultured continuously in the laboratory ever since. The acute effects of carbaryl on the life cycle of rotifer Brachionus calyciflorus was studied under laboratory conditions at(25±1)℃. The results showed that the 24 h LC50 value of carbaryl was 4.868 mg·L-1 for B. alyciflorus, and exhibited a probit model equation:Probit (P)=6.465X-4.444, with 95% confidence interval of 4.538~5.229 mg·L-1. The chronic toxicity showed that carbaryl had a obvious impact on main developmental stages, average life span, net reproduction rate, intrinsic rate of increase and generation time of rotifer except its spawn-ing. Compared with the control group, carbaryl significantly reduced the average life span, net reproduction rate and intrinsic rate of in-crease, with greater effects on life span and intrinsic rate of increase at high concentrations. Larval stage length and embryonic development time extended with increasing carbaryl concentrations. Carbaryl significantly shortened the generation time of the rotifer, except at 2.2 mg·L-1.