关键词: 杀虫剂, 鲫鱼, 急性毒性, 安全性评价

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