Deterministic and probabilistic assessment of heavy metals in herbal teas sold in Lanzhou City, China

Abstract

To evaluate the health risks of consuming herbal teas to residents in Lanzhou City, this study used ICP-MS to determine the Hg, Cd, and Pb content in 131 herbal tea samples (leaf, flower, and fruit) and conducted risk assessment by two methods. The Hg contents were all within safe limit of China, but the Cd and Pb levels in some samples were higher than the same limit. At the P95 exposure level, the ranking of heavy metals based on hazard quotient (HQ) was Pb > Cd > Hg in both methods. The deterministic assessment showed that HQs of Hg, Cd, and Pb were below 1, hazard index (HI) was also below 1, but cancer risk (CR) of Cd was above 10−4. In probability assessment, the HQs of Hg and Pb were less than 1, but the HQ of Cd had a certain probability of being greater than 1, and the CR of Cd is greater than 10−4. Therefore, we conclude that Hg and Pb in herbal teas may not pose a health risk, but Cd pose a health risk to consumers. Thus, measures should be taken to minimize the excessive accumulation of Pb and Cd in the cultivation and production process of floral tea.