Transfer rates of toxic metals during decoction preparation from hebal medicines and safety evaluation of the final decoction products

Transfer rates of toxic metals during herbal decoction preparation were investigated using risk assessment tools. Decoction samples were analyzed using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) and a mercury analyzer after microwave digestion. The average decoction transfer rate (%) for each toxic metal after boiling was 10.5 for As, 4.3 for Pb, 4.1 for Cd, and 2.7 for Hg. A risk assessment of toxic metals in decoctions was performed based on the percentage provisional tolerable weekly intake (PTWI) values for a mean value scenario and a 95th percentile value scenario. Samples were collected of 68 decoctions representing 8 types frequently prescribed by oriental medicine clinics in Seoul, Korea. Both scenarios demonstrated low PTWI values. All decoction samples were safe according to risk assessment results.