氯氰菊酯在茼蒿和油麦菜上的残留行为研究

Study on residue behavior of cypermethrin in chrysanthemum and lettuces

为考察氯氰菊酯在茼蒿和油麦菜上的残留行为,于2016年在山西、山东、天津、安徽、云南和河南进行了氯氰菊酯在茼蒿和油麦菜上的规范残留田间试验。两种作物均包括6地的最终残留量试验和1地的消解动态试验。按照现行的蔬菜中拟除虫菊酯类农药残留测定的国家标准方法对样品进行检测,对方法的有效性进行了评价。田间试验结果表明：氯氰菊酯在茼蒿和油麦菜上的消解动态均符合准一级动力学方程,消解半衰期分别为3.2 d和1.8 d。最后一次施药3、5和7 d后,氯氰菊酯在茼蒿上的残留中值分别为1.64、1.19和0.89 mg/kg,在油麦菜上的残留中值分别为0.84、0.50和0.28 mg/kg。结合不同试验点试验期间昼夜平均气温发现,气温对氯氰菊酯在茼蒿和油麦菜上的残留量有明显影响。施药期间较低的气温下,氯氰菊酯在茼蒿和油麦菜上消解缓慢,残留风险明显增大。建议在实际生产中遇到低温天气应适当延长采收间隔期,另外在开展农药残留田间试验时应重视气象条件对残留试验结果的影响。

In order to determine the residue behavior of cypermethrin in chrysanthemum and lettuces,supervised residue field trial was conducted in Shanxi, Shandong, Tianjin, Anhui, Yunnan and Henan in 2016. Final residue tests in the six regions and pesticide dissipation dynamics test at one place for both vegetables were carried out. According to the current national standard method for the determination of pyrethroid pesticide residues in vegetables, the samples were tested and the effectiveness of the method was evaluated. According to the results of supervised residue trials, the dissipation equations of cypermethrin in chrysanthemum and lettuces fit the first-order kinetics equation with half-lives of 3.2 d and 1.8 d, respectively. The median values of cypermethrin residue in chrysanthemum lettuces were 1.64, 1.19 and 0.89 mg/kg, and the median values of cypermethrin residue in lettuces were 0.84, 0.50 and 0.28 mg/kg, respectively. By comparing the average temperature at different test points during the experiment period, it is discovered that the temperature has a significant effect on cypermethrin residues in chrysanthemum and lettuces. Given the slow decomposition of cypermethrin in chrysanthemum and lettuces, the residue risk increased significantly at lower temperature. It is recommended that the harvest interval should be appropriately extended when it comes to cold weather, and the effect of meteorological conditions on the results of supervised residue trial should be taken into account.