Dissipation, pre-harvest interval estimation, and dietary risk assessment of carbosulfan, dimethoate, and their relevant metabolites in greenhouse cucumber (Cucumis sativus L.).

BACKGROUNDThe dissipation behavior, pre-harvest interval and dietary risk of carbosulfan, dimethoate, and their relevant metabolites were investigated in greenhouse cucumber in Tianjin, northern China, to ensure raw consumption safety. RESULTSCarbosulfan was metabolized to carbofuran, dibutylamine, 3-hydroxycarbofuran and 3-ketocarbofuran, and dimethoate was degraded to omethoate in cucumber fruits and leaves. The dissipation of carbosulfan, carbofuran, 3-hydroxycarbofuran and dimethoate fitted first-order kinetics well, with R-2 ranging from 0.912 to 0.992, and their half-lives were 2.6, 2.7, 2.4 and 5.2days in cucumber fruits and 2.8, 3.0, 4.6 and 2.5days in leaves, respectively. The estimated daily intakes of the active ingredients and their relevant metabolites were 0.1-4% of the corresponding acceptable daily intakes. Acute oral exposure to carbofuran (a metabolite of carbosulfan) represented 367% of the acute reference dose (ARfD) for 1-6-year-old Chinese children and 227% for the general Chinese population. CONCLUSIONA minimum pre-harvest interval of 12days for carbosulfan is proposed to ensure safe consumption of cucumber. The slow dissipation rate of omethoate in cucumber reveals that a longer pre-harvest interval ( 27days) is necessary to prevent dietary risk when dimethoate is applied to cucumber. (c) 2018 Society of Chemical Industry