Assessing transfer of pesticide residues from chrysanthemum flowers into tea solution and associated health risks

Chrysanthemum (Dendranthema grandiflora) flowers are consumed as a popular, traditional herbal tea worldwide. During tea infusion with hot water pesticide residues in chrysanthemum flowers can be transferred into tea solution, posing potential health risks to consumers. Using greenhouse chrysanthemum this study systematically investigated the transfer of metalaxyl-M, fludioxonil, cyantraniliprole, thiamethoxam, and clothianidin (a major metabolite of thiamethoxam) from dry chrysanthemum flowers to tea solution at a range of infusion repetitions, duration and water temperature. The tested pesticides were released into tea solution at varying degrees, and the maximum transfer percentage was 59.9%, 9.8%, 29.4%, 88.2% and 68.4% for metalaxyl-M, fludioxonil, cyantraniliprole, thiamethoxam, and clothianidin, respectively. The transfer of pesticides into tea solution generally increased with increasing pesticide water solubility, water temperature, infusion duration, and pesticide concentrations in dry chrysanthemum flowers, but decreased with increasing octanol-water partition coefficient and the number of infusion repetitions. Risk quotient for pesticide intake via consuming tea solution of chrysanthemum flowers (one and two times of recommended pesticide dosages) ranged from < 0.00003 to 0.0924, indicating a low health risk. This study provides useful information for risk assessment of pesticide residues in greenhouse chrysanthemum flowers and may help establish realistic maximum residue limit of pesticides in chrysanthemum flowers and tea solution.