Research On The Source And Enrichment Regularity Of Fluorine In Groundwater In Yanchi Area

Fluorine is one of the elements that are most widely distributed in the earth's surface environment and also one of the microelements that are indispensable for human body. In specifical content and condition, it is not only nutritious element, but also poisonous element.In general speaking, while fluorine content in groundwater is lower than 0.5mg/l, it will cause dental fluorine; when it is between 1 to 1.5 mg/l, it will make for enamel fluorosis; while it is between 3 to 6 mg/l, it will lead to fluorosis, cause the deformation of skeleton; and when it is higher than 10 mg/l, it will result in deformity fluorosis.In China, Ningxia Hui Autonomous Region is the most noted area of groundwater distribution with high fluorine content, and in Yanchi county, the fluorine content in groundwater is the highest, and groundwater with high fluorine extensively distribute in this area. Because of drinking the groundwater with high fluorine, it make the diseased ratio of suffering from fluorosis was very high. There is 53.6﹪diseased people from the population in this area. It is possible to make diseased human lose labor ability as a result of fluorosis, so the endemic fluorosis is seriously endangering the health of the residents, and also limiting the development of local economy. Therefore it is very important to improve the people living level under looking for lower fluorine content water for the future, by studying the fluorine source of groundwater and investigating the distributing characteristic and regular of enrichment of fluorine in groundwater.Study area of this paper is all the Yanchi county. It is discussed that the fluorine source of groundwater in the area, through the laboratory studies of the leaching processes of soil samples and dissolution processes of rock samples. And deeply analyze the distribution characteristic of fluorine in groundwater. Based on the comprehensive analysis of the influential factors on the enrichment of fluorine in groundwater, it is definitely known that the enrichment regularity of fluorine in groundwater in the study area.The results show that: 1) the main source of fluorine in groundwater in Yanchi area came from this: one hand is the dissolution of fluorine-bearing minerals, mica for instance, in rock and soil; the other hand is the dissolution of adsorptive fluorine in rock and soil system. And on the Southwest district of Yanchi, there is also possible to the occurrence of fluorine which cumulated from the far-back ocean sediments. 2) Geological lithology, climatic conditions, landform, geology and structure conditions, hydro-chemical characteristic of groundwater, acidity-alkalinity of groundwater, quality of aqueous medium and the runoff condition are all the influential factors on the enrichment of fluorine. All these factors influent the enrichment regularity of fluorine in groundwater from all kinds of ways.