大同盆地山阴县—应县一带是典型的高氟地下水分布区,研究针对该区表层(0~20cm)和深层(150cm~200cm)沉积物中总氟含量和形态分布调查,分析沉积物氟含量对区内高氟地下水成因的影响及其来源和控制因素,结果表明:区内沉积物表层和深层中总氟平均含量(表层560.2×10-6,深层564.1×10-6)均高于全国背景值,呈现出自西北向东南增加的趋势。沉积物中水溶态和可交换态氟含量较高,易于被淋溶进入地下水。高氟地下水的分布与沉积物高氟区的分布呈现出差异性。盆地中部河流沿岸地势低洼,是地下水的汇流区,且蒸发作用强烈,易于形成高氟地下水。沉积物氟的空间分布特征则主要受控于自然地质地球化学作用过程,同时也受干旱气候以及人类工农业生产活动的影响。
High fluoride content in groundwater in the Shanyin and Ying Counties,Datong basin brings about a serious environment problem.The fluoride content of top layer(0~20cm)and deep layer(150cm~200cm)sediments in the area was investigated in order to determine its causes and analyze its controlling factors.It is showed that the average fluoride content(560.2×10-6 for top layer and 564.1×10-6 for deep layer)is much higher than that of the background values of China,and tend to increase from northwest to southeast.In the area,the content of water-soluble and exchangeable fluoride in sediments is high and can be easily leached into the groundwater.The distribution of high fluoride sediments is different from that of high F-groundwater.High F groundwater easily occurs in the low-lying central part of the basin along rivers,which is the confluence region of groundwater,and experienced strong evaporation.The spatial distribution of fluoride content in sediment is mainly controlled by natural geological and geochemical process,as well as affected by climate,human industrial and agricultural activities.