百菌清在不同季节设施蔬菜上的残留降解规律研究

Residue and Degradation of Chlorothalonil Use in the Protected Vegetable Fields in Different Seasons

研究了山东省不同季节设施黄瓜和番茄上百菌清的残留状况与残留降解规律,评价百菌清的安全性。结果表明：残留消解动态符合方程Ct=C0e-kt,在春秋两季黄瓜中的半衰期为2.1-5.2天,番茄中的半衰期为3.1-6.0天。300-600倍液施药水平下,施药2-3次,施药间隔为7天,末次施药7天后,百菌清在黄瓜上的残留量为3.101-0.912 mg/kg,在番茄上的残留量为4.093-1.071 mg/kg,残留量低于联合国食品法典委员会（CAC）规定的最大残留限量值（MRL）5.0 mg/kg。百菌清的降解具有明显的季节性差异,按照推荐剂量用药,春季的安全间隔期应在7-10天,秋季应在10-14天。

This paper studies dissipation dynamics and final residues for chlorothalonil in cucumber and tomato cultivation in different seasons of Shandong Province, provide an evaluation for the safe use of chlorothalonil. The results showed that the degradation of chlorothalonil could be described with equation： Ct=C0e-kt. In spring and autumn, the half life of chlorothalonil was 2.1-5.2 d in cucumber and 3.1-6.0 d in tomato, respectively. Chlorothalonil concentration applied at 2-3 times in cucumber and tomato with commanded dosage and 2 times commanded dosage. 7 d after the last spraying, the residues of chlorothalonil were 3.101-0.912 mg/kg in cucumber and 4.093-1.071 mg/kg in tomato, respectively. The residue of chlorothalonil was less than 5.0 mg/kg of maximum residue limit （MRL） of Codex Alimentarius Commission （CAC）. Chlorothalonil degradation had seasonal variations. According to commanded dosage of medication, cucumber and tomato safety interval should be about 7-10 d in spring, and 10-14 d in autumn.