河西走廊浅层地下水主离子特征及水质评价

Main ion characteristics and water quality evaluation of shallow groundwater in Hexi Corridor,Gansu Province

为查明河西走廊浅层地下水的主离子特征及浅层地下水水质状况,运用数理统计法、Piper三线图、相关性分析、Gibbs图及离子比例系数等手段,对研究区75个水样点的水化学指标进行了全面研究。在此基础上,采用了模糊综合评价法与内梅罗指数法对该地区浅层地下水进行了水质评价。结果表明:河西走廊浅层地下水整体偏碱性;Cl^-、Na^+、K^+、NO3^-和SO4^2-在空间上存在较强的变异性;水化学类型整体上为重碳酸硫酸型水;研究区内浅层地下水中的Na^+、SO4^2-和Cl^-很可能有相同的来源;水化学组分主要受蒸发-结晶作用,硅酸盐矿物、蒸发岩盐及硫酸盐溶解的控制。水质评价结果表明人类聚集地浅层地下水水质较差。

In order to find out the main ion characteristics and water quality of shallow groundwater in the Hexi Corridor in Gansu Province,the hydro-chemical indexes of 75 water samples in the study area were analyzed comprehensively by mathematical statistics,Piper diagram,correlation analysis,Gibbs diagram and ion proportional coefficient method.Fuzzy comprehensive evaluation and Nemerow index method were used to evaluate the water quality of shallow groundwater.The results show that the shallow groundwater in the Hexi Corridor are generally alkaline.Cl^-,Na^+,K^+,NO3^-,and SO4^2- show variability in space.In general,the hydro-chemical type is bicarbonate sulfuric acid water.Na^+,SO4^2-,and Cl^-in the shallow groundwater may come from the same source.Hydro-chemical compositions are mainly controlled by evaporation-precipitation,dissolution of silicate minerals,evaporated rock salts and sulfates.The result of water quality evaluation shows that the shallow groundwater quality of human aggregation is poor.