This medical report suggests a possible drawback to having children get their faces painted, at least at some Dragon Boat Festivals:
“A cultural practice of drinking realgar wine leading to elevated urinary arsenic and its potential health risk,” Ying-Nan Zhang, Guo-Xin Sun, Paul N. Williams, Qing Huang, Yong-Guan Zhu, Environment International, 2011 Jul;37(5):889-92. The authors, at the Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China, report:
“Toasting friends and family with realgar wines and painting children’s foreheads and limbs with the leftover realgar/alcohol slurries is an important customary ritual during the Dragon Boat Festival (DBF); a Chinese national holiday and ancient feast day celebrated throughout Asia. Realgar is an arsenic sulfide mineral, and source of highly toxic inorganic arsenic. Despite the long history of realgar use during the DBF, associated risk to human health by arsenic ingestion or percutaneous adsorption is unknown. To address this urine samples were collected from a cohort of volunteers who were partaking in the DBF festivities…. face painting caused arsenic levels in children’s urine to soar to 100 μg L⁻¹ (mean 85.3 μg L⁻¹) 40 h after the initial paint application…. As would be expected in young children, the proportions of organic arsenic in the urine remained high throughout the 88-h monitoring period. However, even when arsenic concentrations in the urine peaked at 40 h after paint application, concentrations in the urine only declined slightly thereafter, suggesting pronounced longer term dermal accumulation and penetration of arsenic. Drinking wines blended with realgar or using realgar based paints on children does result in the significant absorption of arsenic and therefore presents a potentially serious and currently unquantified health risk.”