Lead and arsenic contamination in henna samples marketed in Iran

Since ancient times, people around the world have used natural cosmetics to improve or change the appearance of their nails, skin, and hair. Henna is a plant-based dye that has been used over the centuries for medical and cosmetic purposes. The present work was aimed to investigate the presence of lead (Pb) and arsenic (As) in various types of commonly consumed henna samples in Iran. A total of thirty-nine henna samples from both local and imported products (3 colors in 13 brands) were randomly collected from popular and herbal medicine markets. The atomic absorption spectrometry (AAS) technique was used for the analysis of the samples. The amount of Pb and As in 100% samples was higher than the calculated limit of quantitation (LOQ). The concentrations of Pb and As in the samples were at the ranges of 9.56-16.94 μg/g and 0.25-1.12 μg/g, respectively. The mean level of Pb was higher in black and red products, compared with the green henna. The levels of Pb and As in 53.85% and 7.7% of the henna samples exceeded the permissible limits recommended by the World Health Organization (WHO), respectively. In addition, the mean levels of Pb and As contamination in the imported samples were significantly higher, in comparison to the local henna samples. To our knowledge, this is the first study assessing Pb and As contamination in the henna samples consumed in Iran. Our study demonstrated that there is a potential risk of exposure to Pb through henna in the Iranian consumers.