GEOGRAPHICAL ENVIRONMENTAL CHARACTERISTICS OF ENDEMIC FLUOROSIS IN CHINA

Key words: 
• endemic fluorosis /
• leaching /
• accumulation /
• food chain /
• disease zone

Abstract: Endemic fluorosis is given rise to by human intake of excess fluorine from environment by way of food chain. In China it is one of the extensively prevalent endemic diseases and its distribution shows clearly regional characteristics. In macroscopic sight, three large fluorosis zones may be divided: (1) The arid and semi-arid plains in the north of China. These regions have a dry climate, making fluorine accumulation in the Quaternary deposits. Thus, the drinking water with high content of fluorine is the main cause of the disease formation. (2) The Yunnan-Guizhou Plateau. In the region, rocks and soils rich in fluorine bring about fluorine excess in crop food. This plays an important role in the disease formation. (3) Southeast hills. The hot spring with high content of fluorine leads to fluorosis.The fluorine absorbed by people from the environment is firstly from the drinking water and secondly from the crop food originating from soil. The fluorine in the air can be accumulated in crop leaves to make an impact on people.