Abstract:

Wushan and Fengjie counties are typical fluorosis areas in the three Gorges Reservoir District. In this article, the authors adopted the means of multiobject geochemistry surveying to analyze the Fluoride content in soils of each county along the Yangtze River in Three Gorges Reservoir District, and to analyze their characteristics and distinction of Fluoride in different depths of soils through comparing the fluorosis areas with normal areas. It can be concluded that the value of Fluoride content in soils of Wushan county is the highest among all the counties investigated, Fengjie county is the second, Fulin county the third, and other counties the fourth, such as Fengdu, Wanzhou, Kaixian, Yuyan, Zhongxiang and Changshou, which are similar in either top soils or deep soils. Fluoride content in soils of Wushan county is 2.598 times higher than the average of Fluoride content in the whole country of China, while the value of Fengjie county is 1.883 times higher; the others have a similar value in comparison with the national average level. The topsoil in every place has the geochemistry characteristics of fluorine observed in deep soil. Fluoride in top soil of Wushan county enriches mostly in hypergenesis, where fluorine disease is most serious. Fluoride in Changshou county is lost, where fluorine disease is unfrequent. The value of Fluoride content from different deep soils in fluorosis areas is higher than in nonfluorosis areas. The incidence of fluorosis is correlative with the content of Fluoride, which comes from motherrock and is related to petrogenic element in soil.

Key words: fluorosis, Fluoride element geochemistry, Three Gorges Reservoir District