Abstract: In order to explore the toxic effects of insecticides on fish in paddy fields, this paper took Carassius auratus juvenile as test organism and measured the acute toxicity of 7 insecticides of 5 kinds: imidacloprid, thiamethoxam, triazophos, chlorpyrifos, deltamethrin, pymetrozine and buprofezin commonly used in paddy fields. The results showed that imidacloprid had the weakest toxicity on C. auratus juvenile. The value of LC50 in 24 h, 48 h, 72 h and 96 h were 56.946 mg/L, 53.655 mg/L, 51.151 mg/L, 49.604 mg/L, respectively. The safe concentration of imidacloprid in water was 4.960 mg/L. Whereas, deltamethrin had the highest  toxicity. Its LC50 value in 24 h, 48 h, 72 h and 96 h were 0.032 mg/L, 0.025 mg/L, 0.019 mg/L, 0.015 mg/L, respectively. The safe concentration was 0.002 mg/L. According to the <Experimental Guideline for Environmental Safety Evaluation of Chemical Pesticides>, the toxicity of imidacloprid, thiamethoxam and pymetrozine had low toxicity on C. auratus juvenile. While, Buprofezin and triazophos had moderate toxicity on fish, chlorpyrifos had high toxicity on C. auratus juvenile, and deltamethrin was extreme-toxic. These results would provide scientific basis for reasonable application of insecticides in rice-fish agrosystem.

Key words: insecticide, Carassius auratus, acute toxicity, safety evaluation

摘要： 为探明杀虫剂在稻田使用后对鱼类的毒性效应，以鲫幼鱼为测试生物，测定了5类7种稻田常用杀虫剂对鲫幼鱼的急性毒性。结果表明，吡虫啉对鲫幼鱼的毒性最低，24 h、48 h、72 h、96 h的LC50分别为56.946 mg/L、53.655 mg/L、51.151 mg/L、49.604 mg/L，安全浓度为4.960 mg/L；毒性最高的为溴氰菊酯，24 h、48 h、72 h、96 h的LC50分别为0.032 mg/L、0.025 mg/L、0.019 mg/L、0.015 mg/L，安全浓度为0.002 mg/L。根据《化学农药环境安全评价试验准则》，吡虫啉、噻虫嗪和吡蚜酮对鲫幼鱼为低毒，噻嗪酮和三唑磷对试验鱼类为中毒，毒死蜱对其为高毒，溴氰菊酯对其毒性最大，为剧毒。该结果可为杀虫剂在养鱼稻田的合理使用提供科学依据。

关键词: 杀虫剂, 鲫鱼, 急性毒性, 安全性评价