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

Abstract

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.