Transfer behavior, degradation, and risk assessment of pesticides in Radix Codonopsis and Angelica sinensis during decoction

In this study, a high-resolution mass spectrometry database was used to investigate the concentration dynamics of 22 pesticides in Radix Codonopsis and Angelica sinensis during soaking, first decoction, and secondary decoction. A risk assessment model was established by tracing the transfer of pesticides from the rhizome pieces to the resulting decoction liquids. For both Radix Codonopsis and Angelica sinensis , the dissolved masses of the 22 pesticides increased continuously with soaking time. During decoction, it is a comprehensive result of simultaneous dissolution, chemical degradation, evaporation loss, and repeated partitioning of pesticides between the matrix and the decoction phase, which increases the complexity of residue change. Additionally, the pesticide residue transfer rates were correlated with water solubility and the octanol–water partition coefficient. Risk assessments using the hazard index and risk-ranking methods yielded similar results. Specifically, the pesticide toxicity was deemed acceptably low for Radix Codonopsis and Angelica sinensis . The highest consumption risks were related to organophosphorus pesticides in Radix Codonopsis , and to tebuconazole, methylphosphonates, triazophos, and thiazolphos in Angelica sinensis . Moreover, it was revealed that the dietary intake risk of Angelica sinensis was higher than that of Radix Codonopsis . These findings are expected to provide important data for establishing maximum pesticide residue limits and quality control processes for substances of medicine food homology.