Concentration of neonicotinoid insecticides and their metabolites in Japanese bottled green-tea beverages and their safety evaluation

Abstract

In this study, we determined the concentration of seven neonicotinoid insecticides and 13 of their metabolites in 46 bottled greentea beverages, and estimated the daily intake of neonicotinoids in adults and children from these drinks. Liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC–ESI/MS/MS) analysis revealed that six neonicotinoids and two metabolites were detected in bottled green-tea beverages, and the 50th percentile concentration indicated dinotefuran > thiacloprid > clothianidin > imidacloprid > thiamethoxam > acetamiprid > N-desmethyl-acetamiprid > thiacloprid-amide. The concentration and composition profile of neonicotinoids in bottled green-tea beverages were different between brands; however, no significant differences were observed among manufacturing sites. The concentration of acetamiprid in bottled green-tea beverages was significantly correlated with that of N-desmethyl-acetamiprid. A significant relationship between concentrations of thiamethoxam and clothianidin in bottled green-tea beverages was also observed, suggesting those neonicotinoids are metabolized during the tea leaves cultivation period. The daily intake for neonicotinoids in both adults and children from consumption of bottled green-tea beverages was < 2.1% when compared with the acceptable daily intake (ADI) of neonicotinoids.