氰戊菊酯在香蕉及蕉园土壤中的残留动态与安全性评价

Residual Dynamics and Safe Evaluation of Fenvalerate in Bananas and Its Orchard Soil

采用气相色谱（GC-ECD）及田间试验方法，研究氰戊菊酯在香蕉及蕉园土壤中的残留降解动态。结果表明，氰戊菊酯在香蕉上的原始残留沉积量因不同施药处理有所差异，香蕉及蕉园土壤上的降解速度较缓慢，降解规律符合“C＝C0·e-kt”一级动力学关系。在香蕉上，相关系数r=0.9722～0.9980（P＜0.01），降解系数k =0.0703～0.0767，半衰期T1/2=9.1～9.9 d，降解99%所需要时间T0.99=60.1～65.6 d；在土壤中，k =0.0821，T1/2=8.5 d，T0.99=56.1 d。距第2次施药后62～68 d，最终香蕉的残留量＜0.01 mg·kg-1，土壤中为0.015～0.020 mg·kg-1。在福建蕉区，氰戊菊酯的常规施药方法是间隔期7 d连续2次施用有效剂量112.50 g·hm-2，采样前安全间隔期可推荐为＞13.6 d，产品质量最终可符合GB/T 2763-2012、NY/T 750-2011的要求。

The residue dynamics of fenvalerate in bananas and the soil were studied by using the methods of GC and field experiments. The results showed that the original sediment of fenvalerate in bananas was significant differences among different treatments. Fenvalerate was degrading at a slow rate in bananas and its soil. The residual degradation dynamics of fenvalerate degradation in bananas and its orchard soil could be followed first order kinetic equation ‘C=C0·e-kt’. In bananas, the correlation coefficient （r） ranged from 0.9722 to 0.9980 （P 〈 0.01）, the degradation coefficient （k） ranged from 0.0703 to 0.0767,T1/2 ranged from 9.1 d to 9.9 d andT0.99 ranged from 60.1 d to 65.6 d. On the other hand,r=0.9877 （P〈0.01）, k=0.0821,T1/2=8.5 d andT0.99=56.1 d in its soil. Furthermore, after fenvalerate secondly being applied for 62-68 d, the residue of fenvalerate in banana was 〈 0.01 mg·kg-1, and that in orchard soil was from 0.015 to 0.020 mg·kg-1. The application of fenvalerate into bananas is done according to the regular method in Fujian with an effective dose of 112.50 g·hm-2, and applied twice with an interval of 7 d which means that 〉13.6 d can be recommended as pre-harvest time. The quality safety of their products was fulfilled quality requirements of GB/T 2763-2012 and NY/T 750-2011.