河套地区典型剖面下地下水砷分布及地质环境特征研究

The geological environment characteristics and distribution of groundwater arsenic in the typical section of Hetao Plain

根据河套平原典型剖面浅层地下水砷的分布及地质环境特征,得出自剖面北部扇顶向扇前平原呈现地下水中砷含量逐渐升高的趋势,并在扇前平原和黄河冲湖积平原交界的洼地处,砷浓度达到峰值;向南部进入黄河冲湖积平原,砷浓度普遍较低。结合水化学Schoeller图和地质环境特征,推测此洼地的高砷可能来源于山前深大断裂深部水侵染,并随山前地下水径流在扇前洼地沉积浓缩,在还原环境下解析富集。典型剖面南部黄河冲湖积平原低砷区的地下水水化学组成与黄河水水化学Scoeller曲线极为相似,说明此处地下水砷来源与黄河水灌溉有着密切关系。

Base on the distribution of groundwater arsenic and the geological environment characteristics in the typical section of hetao plain,the concentration of arsenic increased gradually form fan-head to fan front plain in the typical section,the concentration of arsenic reached its peak in the junction of fan front plain and the Yellow River alluvial plain.The concentration of arsenic is low in the Yellow River alluvial plain.According to hydrochemistry schoeller diagram and the characteristics of the geological environment,the depression center of the high concentration of arsenic may be derived from the fracture deep of piedmont.Then the As concentrated in the depression sub-face before alluvial fan,and restored in the reducing environment.In the south of the typical section,the schoeller curves of groundwater chemical composition is similar to the chemical composition of Yellow River water.The groundwater arsenic sources is closely related to the Yellow Rriver water.