连云港北部地区高氟地下水分布特征及成因

Distribution and genesis of high-fluoride groundwater in northern Lianyungang area

为研究连云港北部地区地下水氟水文地球化学特征,采集测试了63件地下水样品,分析了高氟地下水的空间分布特征及其形成的水文地球化学过程。结果表明,地下水中氟的质量浓度呈现出随着地下水流动而逐渐升高的变化规律,高氟地下水分布于海湾低平原及平原洼地。HCO_3^-质量浓度高的弱碱性水化学环境是促进氟富集、并增强其从沉积物向地下水中转化的主要因素。高氟地下水的形成是长期地质作用和地球化学演化的结果,矿物溶解-沉淀作用、蒸发浓缩作用、阳离子交替吸附作用是控制地下水中氟富集的主要水文地球化学过程。

In order to study hydrogeochemistry of the fluoride in groundwater in northern Lianyungang area, the authors analyzed 63 groundwater samples and investigated the distribution and genesis of high-fluoride groundwater. The results show that the concentration of fluoride in groundwater tends to increase with the groundwater flow. The high-fluoride groundwater areas are distributed in low gulf plain and depression. The alkaline water environment with high concentrations of sodium and bicarbonate is the main factor responsible for fluoride enrichment and transfer of fluoride from sediments to groundwater. The formation of high- fluoride groundwater results from prolonged geological and geochemical evolution. The hydrogeochemical processes including mineral dissolution and precipitation, evaporation and concentration, cation exchange and adsorption are the dominant factors for the enrichment of fluoride in groundwater.