Numerous natural preparations in traditional Chinese medicine are prepared as decoctions. Processing factors (PFs) comparing the levels of pesticide residues in decoctions to those in the corresponding unprocessed products should be considered in exposure assessments. Thus, this study determined the residue levels of six pesticides (chlorpyrifos, phoxim, imidacloprid, thiamethoxam, fenpropathrin, and emamectin benzoate), as well as 3,5,6-trichloropyridinol, the primary metabolite of chlorpyrifos, and clothianidin, the main metabolite of thiamethoxam in Baishao, Paeoniae radix lactiflora (Fam. Ranunculaceae). The results showed that significant time-response effects were present for the release of pesticides from P. radix. The PFs calculated were < 1, indicating a significant reduction in pesticide residues after TCM processing. The water solubility and partition coefficient values of the pesticides may have played a basic role in the dissipation of the residues during the TCM decocting process. A risk assessment based on the hazard quotient with PFs revealed that exposure to pesticide residues in P. radix was far below the levels that might pose a health risk. In conclusion, the results presented here are of theoretical and practical value for the safety evaluation of TCMs.

Traditional Chinese medicines (TCMs) are widely used to treat various diseases in China and some countries, and TCM products are becoming increasingly available and popular worldwide. But TCMs are facing the challenge of heavy metal pollution. In this work, we examined the total contents and fractionations of Pb, Cd, Hg, and Cu in six TCMs (Angelicae Sinensis Radix (ASR), Chuanxiong Rhizoma (CR), Polygonati Rhizoma (PR), Astragali Radix (AR), Carthami Flos (CF), and Paeoniae Radix Rubra (PRR)) and evaluated the health risk of four heavy metals in these TCMs. The results showed that Cd, Pb, and Cu contents were considerably high and the amount of Cd in six TCMs, Pb in CR, ASR, AR, and CF, and Hg in ASR, PR, and PRR exceeded the limit values. The predominant fractions of Pb, Cd, and Cu were exchangeable and carbonate fractions in six TCMs; Hg mainly existed in organic and residual fractions. The average daily intake dose (ADD) and target hazard quotient (THQ) of Pb based on total content and total THQ of four heavy metals based on bioaccessible fractions in AR and PRR exceeded the safety guideline. These results indicated that the potential health risk could occur by taking these TCMs.