高效氯氰菊酯在苹果和土壤中的消解动态及残留安全性评价

Degradation Dynamics of Beta-cypermethrin in Apple and Soil and Its Residue Safety Evaluation

[目的]研究高效氯氰菊酯在苹果和土壤中的残留动态情况。[方法]2007～2008年在北京郊区和安徽萧县两地进行高效氯氰菊酯消解动态及最终残留试验,用气相色谱测定其含量。[结果]高效氯氰菊酯在苹果和土壤中的平均回收率分别为83.19%～90.04%和82.29%～90.50%;相对标准偏差分别为4.26%～9.65%和5.46%～10.79%。消解动态结果表明,高效氯氰菊酯在苹果中比在土壤中消解快,其消解半衰期在苹果和土壤中分别为5.04～6.99d和8.95～13.64d;2年试验表明,4.5%高效氯氰菊酯微乳剂按45.0和67.5mg/kg(有效成分浓度)推荐剂量施药2～3次,采收期距最后1次施药间隔14d,苹果中高效氯氰菊酯残留量均低于2.0mg/kg,说明该药按推荐剂量使用是安全的。[结论]高效氯氰菊酯属于易降解农药,其在苹果及土壤中的残留量与使用浓度和施药次数无明显相关性。

[Objective]The propose was to study the residue dynamics of beta-cypermethrin in the apple and soil.[Method]The tests of degradation dynamics and final residue for beta-cypermethrin were conducted in 2 places of Beijing suburbs and Xiaoxian County of Anhui Province and the beta-cypermethrin contents were determined by gas chromatography.[Result]The average recoveries of beta-cypermethrin in the apple and soil were 83.19%-90.04% and 82.29%-90.50% resp.,with the relative standard deviation being 4.26%～9.65% and 5.46%～10.79%,resp.The degradation dynamics test showed that the beta-cypermethrin was more rapidly degraded in the apple than that in the soil and the degradation half-life of beta-cypermethrin in the apple and soil was 5.04-6.99 d and 8.95-13.64 d resp.The two-year experiment also showed that when the apple was sprayed with the 4.5% beta-cypermethrin ME at the recommended rate of 45 and 67.5 mg/kg for 2 to 3 times and the last application was done in the interval of 14d before harvesting,the residue of beta-cypermethrin in the harvested apple was lower than 2.0 mg/kg,indicating that it was safe to apply the beta-cypermethrin to the apple with the recommended rate.[Conclusion]The beta-cypermethrin belonged to the pesticide that was easy to be degraded and its residue amount had no significant correlation with its applying concn.and application times.