Dissipation and Dietary Risk Assessment of Thiacloprid and Tolfenpyrad in Tea in China

Pesticides are widely used to maintain tea yields. For achieving satisfactory effects on pests, multiple pesticides in a low application dose have been the trend at present. In this study, we investigated the dissipation and dietary risk assessment of thiacloprid and tolfenpyrad. A method for the determination of thiacloprid and tolfenpyrad was developed. The recoveries ranged from 73% to 105% with standard deviations between 0.7% and 8.3%. Limits of quantification were 0.01 mg/kg for both pesticides. Field trials were conducted in China in 2021. The half-lives were in ranges of 3.22 to 8.45 days for thiacloprid and 2.91 to 10.50 days for tolfenpyrad. The terminal residues were in the range of 0.04–2.55 mg/kg for thiacloprid and <0.01–4.00 mg/kg for tolfenpyrad, respectively. Finally, a dietary risk assessment was conducted representing the acceptable risk of the two pesticides, which of ratios were all less than 100%. The safe pre-harvest interval of 14 days was suggested. This study can serve as a guide for the rational application of thiacloprid and tolfenpyrad in tea, which also ensures the safety of human health.