Residue degradation and metabolism of dinotefuran and cyromazine in Agrocybe aegerita: A risk assessment from cultivation to dietary exposure

Sensitive, simple and quick methods for determination of dinotefuran, cyromazine, and the metabolites 1-methyl-3-(tetrahydro-3-furylmethyl) guanidine (DN), 1-methyl-3-(tetrahydro-3-furylmethyl) urea (UF), and melamine in Agrocybe aegerita were established and validated by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The dissipation and residues of these compounds in A. aegerita were investigated. The field results showed that dinotefuran and cyromazine dissipated rapidly with half-lives ranging from 24.9 h to 38.5 h. The terminal residues of total dinotefuran (the sum of dinotefuran and its metabolites), cyromazine, and melamine in fresh mushroom samples collected with sampling intervals of 3 d to 6 d ranged from 0.089 to 0.652 mg/kg, 0.593 to 2.054 mg/kg, and 0.002 to 0.005 mg/kg, respectively. During the drying processes of A. aegerita, the processing factors of dinotefuran, cyromazine, DN, UF, and melamine were 0.028, 0.012, 0.301, 0.002, and 0.001, respectively. Given that cyromazine and dinotefuran are not registered for use on A. aegerita, dietary risk was assessed. Based on a consumption survey, risk quotient (RQ) values significantly below 1 implied that the risk of A. aegerita consumption was acceptable, although the risk for children was relatively higher. The findings could provide valuable guidance for the appropriate use of these insecticides in A. aegerita cultivation and serve as a scientific reference for setting corresponding maximum residue limits (MRL) in China.