Research on Fluoride Pollution and Fluorosis in Rural Areas of China

A China-Japan joint project was carried out to study the incidence of fluorosis caused by coal burning in China from 1995 to 1997. The health survey covered a control area and two flourosis areas. In those research areas, drinking water was not polluted with fluorides. The survey was designed to analyze the health status of people exposed to fluorides and evaluate the relationships between the dose and incidence of fluorosis. The concentration of airborne pollutants in both indoor and outdoor air was measured. The concentration of fluoride in the urine was analyzed and definite diagnoses for dental fluorosis and skeletal fluorosis were determined. As a result, the incidence of coal burning fluorosis was confirmed in studied areas. Moreover, the fluorosis was caused not only by the direct inhalation of the airbone fluorides in indoor air but also by the intake of cereals polluted with fluorides. Fluoride was contained in both coal and soil. Therefore the mixture of coal and soil used for the adjustment of fire energy contributed to the air pollution to a great extent. The typical polluted crops were red pepper, corn and potato. An extremely high concentration of fluoride in the urine of residents in the polluted areas was detected.