The Source Of Fluoride In The High - Fluoride Spring Water Of Eryuan County In Yunnan Province And Its Influence On The Surrounding Environment

Eryuan county is located in the northwest of Yunnan province. Before the 80’s of 20 th century,the spring water was the main drinking source of Niujie,Sanying,Yousuo and Cibithu town.Due to the high fluoride content in the hot spring water, the fluorosis is epidemic. The phenomenon has attracted the attention of the local government. In the late 1980 s, this area began to improve water. The township unified running water,average fluoride content in drinking water by 1983 of 4.58 mg / L fell to 2013 of 0.68mg/L. The effect of water quality improvement is obvious The average prevalence rate of dental fluorosis decreased from 63.65% to 26.93% in 1983 and 2013. So that the fluorosis has been a degree of control,but endemic fluorosis has not been fully resolved. In order to identify the reasons for the still epidemic fluorosis in this district after improvement water, combined with the findings of the research group in 2008, the article took the fluorine source as the breakthrough point, explored the fluorine source of food, soil, vegetables etc in depth of this area. Combined with local geological background, research group investigates prevalence rate of dental fluorosis again in the fluorosis area, screens surrounding towns, checks whether the emergence of new endemic area or not. Analyses characteristics of fluorine content of the soil, water(including spring water, tap water, shallow well water), food, vegetables etc.Check whether the fluorine content is abnormal. The survey of dental fluorosis, the average prevalence rate of Niujie, Sanying reaches 41.05%, and the Yousuo, Cibihu is 12.82%, there is no new endemic area. Test results for collected samples showed that: the average value of spring water fluoride content in the 4 townships is 6.15mg/L, between 3.27—9.05mg/L. Tap water fluorine content between 0.07 —0.17 mg/L,with an average of 0.12mg/ L;shallow well water is 1.89 mg / L,between 1.54 —2.10mg/L. Compared the fluorine content in national drinking water standard 1.0mg/L, the fluorine content in tap water samples reached the standard, shallow well water slightly more than the standard, spring water seriously overweight. The water soluble fluorine content in the soil near the hot spring point is 389.31 ug / g, not found spring point is 336.73 ug /g. The fluorine content of the soil in the exposed spring water district is higher than the no exposed area, but the background value in our country, the average fluorine content(453 ug/g) showed that the area of soil background value is not high fluorine content. Hot springs near the point of total fluoride content in soil between 630.48-1000.27ug/g, an average of 782.21 ug/g, significantly higher than the average fluorine content background values in our country. Hot spring water irrigates food, vegetables, average 10.07 ug/g fluorine content, shallow well water irrigate food vegetable fluorine content is 3.43 ug/g, fluorine content is more than the national standard of the fluoride 1.0 ug/g, hot spring water irrigation exceeds bid badly.Influence of hot spring water fluoride concentration in the factors including regional geological environment, landscape, rock properties, water chemical characteristics and hydrogeological conditions.This area is in the the northern extension of Honghe- Erhai fault zone, hot water generated by fault zone fully dissolved fluoride in surrounding rock. The fluoride was not dissolved in the soil, because it’s lack of water in the natural weathering process of rock-soil,so the background value of soil fluorine is not high in this region. Relatively flat topography provides favorable conditions for hot water storage, at the same time basin is helpful for fluoride enrichment. HCO3-Na, HCO3SO4-Na, HCO3SO4-Na·Ca-types water is more conducive to fluoride dissolution.For easy absorption by human body,The above factors Er hot spring water source region fluorine content value is higher.Due to the variation in this area after water fluorosis which is still the popular reason is that local residents have been using hot spring water with high fluorine content for a long time for irrigating food and vegetables.Random discharging caused the leakage to the shallow groundwater in the hot spring area. The drinking water shortage is still from the spring water.Fluoride enters the body through the above ways, it should change from irrigation water from the discharge of hot spring water if need fundamentally to solve the problem of fluorosis, the hot spring water dropping with science approaches by means of fluoride to be drinking water standards.