Endemic fluorosis in China from ingestion of food immersed in hot spring water

Abstract

Fengliang was identified as a town with endemic dental fluorosis during an overall screening to identify areas with endemic fluorosis in Guangdong Province. Fengliang is situated in a hot spring area in the eastem part of Guangdong. Among a population of 8000, the prevalence of dental fluorosis inchildren aged 8 to 15 years (total 837) reached 50%, but the fuoride content of drinking water was less than 0.4ppm. In comparison, the United States federal standard for fluoride in drinking water is 4 ppm (Federal Register, 1985). The California drinking water standard is 1.4 to 2.4 ppm, depending on ambient temperature (California Administrative Code Title 22). In order to determine the cause of the dental fluorosis in Fengliang, a systemic study was conducted to investigate dietary intake of fluoride as a possible source of exposure. Researchers examined hot spring water and foods for fluoride content on the basis that the local population routinely immersed their vegetables in hot spring water.