噻虫嗪在小麦中的残留消解动态及风险评估

为了评价20%噻虫嗪悬浮剂在小麦上使用的安全性,于安徽、吉林2地进行了田间试验,采用高效液相色谱-紫外分析法研究了噻虫嗪在小麦植株、麦秆和麦粒中的消解动态和最终残留。结果表明:噻虫嗪在小麦植株中的消解规律符合一级动力学模型,其半衰期分别为4.6和5.9 d。按推荐剂量(有效成分)12.6 g/hm2施药2次,在距最后1次施药后第21 d及以后收获的麦粒中噻虫嗪的残留量均未超过日本等国规定的最大残留限量(MRL)值(0.02 mg/kg)。通过计算得出每人每天从小麦中所摄入的噻虫嗪仅为0.035 6 mg,风险商值(RQ)为0.028,处于安全水平。

Residue decline study and risk assessment of thiamethoxam in wheat

In order to evaluate the safety and regular use of thiamethoxam 200 g/L SC,the terminal residue and decline dynamic of thiamethoxam in wheat plant,wheat straw and wheat grain were investigated and the samples were analyzed by HPLC-UVD in Anhui and Jinlin Province.The results indicated that the decline curves of thiamethoxam in wheat plant accorded the first-order kinetics.The half-life of thiamethoxam was 4.6 d in Anhui and 5.9 d in Jinlin.The terminal residue indicated that when the wheat plant was sprayed 2 times with thiamethoxam 200 g/L SC with the recommended dosage of 12.6 g a.i/hm²,and the last application was done 21 d after harvesting,the residue of thiamethoxam in wheat were lower than the MRL of Japan:0.02 mg/kg.By calculating,the intakes of thiamethoxam per man and per day from wheat was 0.035 6 mg.Risk quotient(RQ) was 0.028.The residue could be declined to the safety level.