Pesticide residues in common and herbal teas combined with risk assessment and transfer to the infusion

Abstract

The use of pesticides is permitted in tea cultivation, but many of them are withdrawn in Europe. The aim of this study was a comprehensive assessment of pesticide occurrence in common teas (black, green, red, white, and black flavored) and herbal teas (lemon balm and mint) and their transfer to the infusion. Among 603 pesticides, 24 were detected, of which 9 were withdrawn in Europe. Of the 64 tea samples, 47% had pesticide residues and 2% exceeded the European Maximum Residue Level (EU MRL; 572% for linuron/mint). The highest mean concentrations of the most common pesticides were 336 ng g⁻¹ (quizalofop-P-ethyl/mint), 108.4 ng g⁻¹ (MCPA/lemon balm), and 92.4 ng g⁻¹ (glyphosate/red tea). A short time of brewing (5 min) had a higher transfer factor (TF) of most pesticides to the infusion (TF = 0.85/thiacloprid), compared to 30 min brewing (TF = 0.75/thiacloprid). Moreover, the physicochemical properties of detected pesticides, mainly density and melting temperature had a crucial impact on their transfer to the infusion. Acute risk was the highest for linuron/mint/children (17% of Acute Reference Dose; ARfD). Despite the withdrawal of some pesticides in the EU, they are still detected in tea samples. The results are pivotal for human health and highlight the need for further legislative action for tea.