Refining health risk assessment for determining arsenic and cadmium safety limits in an herbal medicine and its cultivation soils

Abstract

The contents of arsenic (As) and cadmium (Cd) in the herbal medicine Panax notoginseng (PN) have attracted public attention for the safe use of PN. Species-specific safety limits for As and Cd based on health risk assessment are an effective measure for the safety of PN consumption. To decrease the uncertainty of risk assessment, the gastrointestinal bioaccessibilities of As and Cd in PN, the influence of pharmaceutical processes, and individual variations in the dosage and duration of PN preparations were introduced for probabilistic health risk estimation. The As and Cd concentrations in PN materials from three major medicinal material markets were in the ranges of 0.11–1.26 and 0.07–1.97 mg/kg, respectively. The gastrointestinal bioaccessibilities of As and Cd in PN determined by an in vitro experiment were 64.7 ± 3.9% and 84.1 ± 10.1%, respectively. There was almost no noncarcinogenic health risk; however, long-term consumption of the PN preparation may induce 3.53% of consumers to have carcinogenic risks exceeding 1 × 10−4. The safety limits of As and Cd in PN were then determined to be 1.5 and 3.6 mg/kg, respectively, based on this acceptable carcinogenic risk level. Furthermore, the bioaccumulation of As and Cd in PN and their impacts on pharmaceutical components were studied based on our investigation in 19 PN plantations in major production areas. The safety limits of As and Cd in the soils were thus determined to be 5.5 and 7.3 mg/kg, respectively. The establishment of species-specific safety limits for commonly used herbal medicine was proposed because current standards cannot ensure the safe usage of PN.