Risk assessment and residue behavior of a novel pesticide cyetpyrafen and its metabolites from fresh tea leaves to tea infusion

1. Residual dissipation of cyetpyrafen and its three metabolites was studied across tea cultivation, processing, and brewing. 2. Cyetpyrafen dissipated rapidly (t 1/2 =0.59 d) in the field, with M-309 identified as the major metabolite. 3. The dietary intake risk of cyetpyrafen from tea consumption was negligible to human health. 4. Cyetpyrafen and its main metabolites were predicted to be harmful to non-target organisms. China has limited acaricide options for tea plantations. Cyetpyrafen, a novel domestic acaricide with high efficacy, low toxicity and a negative temperature coefficient, offers an alternative for tea pest control; however, its residue fate in tea remains unclear. This study developed a method to simultaneously detect cyetpyrafen and its metabolites (M-309, M-325-1, and M-409-3) in different tea matrices to investigate their fate. Recoveries of compounds ranged from 73.4% to 106.2% with the relative standard deviations (RSDs) below 12.0%. During tea cultivation, the dissipation half-life of cyetpyrafen was 0.59 d, with M-309 as a major metabolite. The residues of cyetpyrafen and M-309 were affected by different processing stages, especially water loss and high temperatures during fixing, drying and withering. The total processing factors ranged from 1.39 to 1.71 for green tea and 1.48 to 2.28 for black tea (processed from fresh tea leaves sampled at 1, 5, and 7 d), respectively. The leaching rates of cyetpyrafen from green tea and black tea into tea infusions were 7.4% and 6%, respectively. The risk associated with cyetpyrafen intake from tea consumption was low, with risk quotient values below 100%. However, theoretical calculation indicated potential harm to non-target organisms from its metabolites. This research provides a reference for the safe and efficient use of cyetpyrafen in tea gardens.