The fluorine sources in the endemic fluorosis areas,western Guizhou

The Upper Permian coal-bearing strata are widespread in western Guizhou.The residents’ health has long been seriously threatened by the coal-burning endemic fluorosis.The authors in the present paper contend that the fluorine which leads to the endemic fluorosis has polyphyletic origins,including: (1) high-fluorine rocks such as claystone,coal and shale; (2) high-fluorine soils originated from the weathering of the high-fluorine rocks including coal; (3) the crops planted in the high-fluorine soils,and (4) higher contents of fluorine in the indoor air polluted by the waste smoke from the burning coal, food toasted by the burning coal and water with higher contents of fluorine.