Abstract: The degradation dynamics of cypermethrin in bananas and its orchard were studied by using GC and field experiment. The results showed that the original sediment of cypermethrin in bananas was relatively lower. The rule of cypermethrin degradation in bananas and the soil were well-fitted with first-order kinetics. On one hand, two different application doses share the same degradation coefficient, T1/2 ranged from 12.1 d to 12.88 d and T0.99 ranged from 80.3 d to 85.1 d in bananas. On the other hand, in the soil T1/2 and T0.99 were 8.0 d, 52.9 d respectively. Furthermore, after applying for 62～70 d, the residue of cypermethrin in banana orchard was less than 0.01 mg/kg. The application of cypermethrin into bananas according to the regular method in Fujian, which is an effective dose of 56.25 g/hm2, was applied continually with an interval of 7 d. So it meaned that more than 7 d can be recommended as pre-harvest time. The quality safety of their products was fulfill quality requirements of NY/T 750-2011.

Key words: banana, soil, cypermethrin, residual, degradation dynamics, safety assessments

摘要： 采用气相色谱法及田间试验法研究氯氰菊酯在香蕉及蕉园土壤上的残留降解动态。结果表明，氯氰菊酯在香蕉上的原始沉积量较低，不同施药剂量有明显的差异。氯氰菊酯在香蕉及蕉园土壤上降解速度较缓慢，残留降解规律均符合一级动力学关系，在香蕉上两种施药剂量的降解速率相接近，半衰（T1/2）为12.1～12.8 d、降解99%需时（T0.99）为80.3～85.1 d；在蕉园土壤上T1/2、T0.99分别为8.0 d、52.9 d。在香蕉上距第2次施药后62～70 d最终产品残留量＜0.01 mg/kg。在福建蕉区氯氰菊酯按常规施药方法，间隔期7 d连续施用有效剂量56.25 g/hm2两次，施药安全间隔期可推荐为＞7 d，最终产品质量符合NY/T 750-2011规定的MRL要求。

关键词: 香蕉, 土壤, 氯氰菊酯, 残留, 降解动态, 安全性评价