Heavy metal concentrations in Chinese folk medicines for treating epilepsy in children in rural China, and their prescription by village doctors: a cross-sectional survey

Background In areas of rural China inhabited by minority groups, local village doctors often use traditional Chinese folk medicines to treat primary epilepsy in children. However, such folk medicines have been implicated in heavy metal poisoning in children. This study determined the heavy metal concentrations of samples of folk medicines, and examined the attitudes of local doctors regarding their use. Methods Inductively coupled plasma-optical emission spectrometry (ICP-OES) was used to identify toxic heavy metals from 33 samples of folk medicines (28 mixtures and five monomers) from eight counties in western Hunan Province, China, from March 1, 2018 to March 30, 2018. Village doctors in western Hunan Province, China, participated in face-to-face interviews based on a questionnaire focused on knowledge about the heavy metal toxicity of folk medicines. Findings Four toxic heavy metals—cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As)—were identified in the samples. The mean (SD) concentrations of Cd, Pb, Hg, and As, were 0·513 (0·237), 5·145 (2·404), 0·298 (0·179), and 0·321 (0·106) mg/kg, respectively. Furthermore, Cd was found in 76%, Pb in 68%, Hg in 38%, and As in 24% of the samples. These levels exceeded the Chinese legal limits of 0·3, 5·0, and 0·2 mg/kg, respectively. The highest concentration of lead found in a sample was 65·42 mg/kg. The questionnaire was completed by 112 village doctors, of whom 68% considered folk medicine to be safe for treating epilepsy and 77% believed that some heavy metals, especially lead, were efficacious for treating epilepsy. Interpretation Some folk medicines contain heavy metal concentrations exceeding safe limits. The use of folk medicines by rural village doctors to treat epilepsy might lead to increased heavy metal exposure in children in these rural areas. It is important to focus on this issue given the potential harmful effects on children's health. There is a clear need for multifaceted interventions that target village doctors to improve their knowledge of heavy metal poisoning in children. Funding This study was supported by the Yale-China Association.