Distribution Characteristics And Development Mechanism Of Fluorine In Deep Groundwater In Cangzhou

High concentration of fluorine is one of hydrochemical characteristics in deep groundwater in Cangzhou. To reflect the distribution characteristics and development mechanism of fluorine concentrations in deep groundwater in Cangzhou, samples of 1980 and 2014 were collected and analyzed, then the distribution characteristic and evolution simulation were researched. The horizontal distribution characteristics were revealed with the use of ArcGIS. The results show that the concentrations of fluorine in deep groundwater increased from 1980 to 2014 in Cangzhou. The concentration of fluorine in deep groundwater larger than 2 mg/L distributed mainly in middle of Changzhou, and those distribution areas accounted for about fifty percent of the whole Changzhou area, which leads to the reduction of available groundwater. Horizontal hydrogeochemical model and vertical solute transport model were built respectively by using PHREEQC and MODFLOW. Depending on the distribution regularity of fluorine in groundwater in Cangzhou area, two sampling points were selected, which located upstream and downstream respectively on the same flow path along the flow direction. The sampling data of corresponding sampling points in 1980 and 2014 were used to simulate the hydrogeochemical process of fluorine in deep groundwater, the results show that the dissolution of fluorite was the main reason for the increasement of fluorite in deep groundwater in this area. According to the solute transport model of deep groundwater, the high fluorine in ? aquifer comes from the higher concentration of fluorine in IV aquifer by vertical migration. The solute transport model was calibrated according to the concentration of fluorine in ? aquifer of 1980 and 2014, then the calibrated model was used to predict the average fluorine concentration in III aquifer, the result shows that concentration will reached 1.64 mg/L at 2030.The author predicts that the exploitation of deep groundwater will lead to continuous increasement of fluorine in deep groundwater in Cangzhou, and long-term drinking such water will do harm to health of Cangzhou residents.