Major Geochemical Controls on Fluoride Enrichment in Groundwater: A Case Study at Datong Basin,Northern China  

作　　者：李亮 王焰新 吴亚 李俊霞 

机构地区：[1]State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences [2]School of Environmental Studies,China University of Geosciences

出　　处：《Journal of Earth Science》2013年第6期976-986,共11页地球科学学刊（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.41120124003);the Ministry of Education of China

摘　　要：Hydrogeochemical investigations were carried out in the Datong Basin, northern China to understand the sources and mechanisms of fluoride enrichment in the groundwater. The re- sults indicate that fluoride concentrations reached up to 7.2 mg/L, and the hydrochemical type changed from Ca-HCO3, Ca-Mg-HCO3 water in the recharge areas to Na-HCO3, Na-Mg-HCO3 in the flow-through area and ultimately to Na-CI-HCO3, Na-SO4-CI and Na-CI in the discharge areas. The to- tal fluorine contents in the soils ranged between 277.6 and 1 292.5 mg/kg, which can provide large amounts of fluorine from fluorine-bearing minerals, such as fluorite, biotite and amphibole. The con- centration of water-soluble fluorine ranged from 3.9 to 49.9 mg/kg （mostly less than 1% of the total fluorine） in the soils and rocks that, may have released sufficient fluorine into the groundwater. The results of PHREEQC simulations indicate that most of the analyzed samples are under-saturated with respect to fluorite （CaFz） from the recharge area to the discharge area. The fluctuation of F concentra- tion in the 11 months indicates that the seasonal variation and the agricultural activity also affect the fluoride content in the groundwater. Fluoride enrichment in groundwater is predominantly controlled by fluorite solubility, residence time, evapotranspiration intensity and seasonal variation in this arid and semi-arid area.Hydrogeochemical investigations were carried out in the Datong Basin, northern China to understand the sources and mechanisms of fluoride enrichment in the groundwater. The re- sults indicate that fluoride concentrations reached up to 7.2 mg/L, and the hydrochemical type changed from Ca-HCO3, Ca-Mg-HCO3 water in the recharge areas to Na-HCO3, Na-Mg-HCO3 in the flow-through area and ultimately to Na-CI-HCO3, Na-SO4-CI and Na-CI in the discharge areas. The to- tal fluorine contents in the soils ranged between 277.6 and 1 292.5 mg/kg, which can provide large amounts of fluorine from fluorine-bearing minerals, such as fluorite, biotite and amphibole. The con- centration of water-soluble fluorine ranged from 3.9 to 49.9 mg/kg （mostly less than 1% of the total fluorine） in the soils and rocks that, may have released sufficient fluorine into the groundwater. The results of PHREEQC simulations indicate that most of the analyzed samples are under-saturated with respect to fluorite （CaFz） from the recharge area to the discharge area. The fluctuation of F concentra- tion in the 11 months indicates that the seasonal variation and the agricultural activity also affect the fluoride content in the groundwater. Fluoride enrichment in groundwater is predominantly controlled by fluorite solubility, residence time, evapotranspiration intensity and seasonal variation in this arid and semi-arid area.

关 键 词：hydrogeochemical Datong Basin FLUORIDE groundwater. 

分 类 号：X131.2[环境科学与工程—环境科学]