Assessment of lead and cadmium in fifty-four Indian herbal medicine: tribal and marketed varieties

The objective of this study was to assess the toxic metal content in herbal medicines being used by Indian people. Trace elements, lead (Pb) and cadmium (Cd), in fifty-four herbal medicines (marketed and tribal varieties) of India were estimated, and the potential health risks were characterized by estimating the tolerable daily intake (TDI) and the total hazard quotient (THQ) associated with their consumption. A total of 12% of the marketed varieties had Pb above WHO permissible limits of 10 mg Pb/kg. In tribal varieties, none of the samples exceeded this limit. In contrast, all the marketed varieties and 17% of the tribal varieties exceeded WHO limit of 0.3 mg Cd/kg. Consumption of ~ 0.01 kg of herbal medicine per day contributed almost 20–28% of TDI of Pb and Cd for marketed varieties and < 10% for tribal varieties. Although the consumption of the Indian herbal medicine, especially the tribal varieties, posed no immediate concern as the average THQ was less than 1, 24% of the marketed varieties had a higher metal burden and could pose threat on long-term use. Our findings advocate the use of tribal medicines for therapeutic purposes owing to a relatively lesser metal burden than the marketed varieties. However, for the marketed varieties, appropriate standardization in terms of effective quality control and consistency is needed to ensure the health of the consumers.