摘要
自2014年水利部组织实施华北地下水超采综合治理工作以来,保定平原地下水位逐步回升,然而地下水化学要素及质量变化缺乏系统研究.以2014～2022年采集的217组保定平原浅层地下水样品为研究对象,运用数理统计分析、Piper三线图、Gibbs图及离子比例系数等方法,分析了地下水水化学特征、空间分布规律及主要控制因素,采用内梅罗指数法和模糊综合评价法对地下水质量进行了评估.结果表明:①研究区地下水中阴离子以HCO3-为主,阳离子在山前冲洪积平原区(Ⅰ区)主要为Ca2+、Mg2+,冲积平原区(Ⅱ区)主要为Ca2+、Na+,自西部山前到东部平原地下水化学类型由HCO3-Ca·Mg型渐变为HCO3-Na·Ca·Mg型或HCO3-Na·Mg型.②研究区地下水中Na+、Mg2+、HCO3浓度多年间较为稳定,Ca2+、Cl-、SO42-、TDS浓度在2014～2021年波动下降,2021～2022年明显上升,水化学成分主要受岩石风化、溶滤作用和阳离子交替吸附作用影响.③内梅罗指数法和模糊综合评价法评价结果显示,Ⅲ类及以上样品占比分别为73.73％和97.24％,说明多年来该区域地下水质量较为稳定.研究成果可为该地区地下水资源的可持续利用提供科学依据.
Abstract
Since comprehensive management of excessive groundwater exploitation in the North China Plain was carried out by the Ministry of Water Resources in 2014,the groundwater level in the Baoding Plain has gradually risen.However,there remains a lack of systematic research on the chemical elements and quality changes of groundwater in the Baoding Plain.Using 217 sets of shallow groundwater samples collected from the Baoding Plain between 2014 and 2022,we first used Mathematical statistics,the Piper diagram,Gibbs diagram,and ion ratio method to analyze the hydrochemical characteristics,spatial distribution,and major controlling factors,and then adopt the Nemerow index method and fuzzy comprehensive evaluation method to evaluate the ground-water quality.The results showed that:① The anions in the groundwater were dominated by HCO3-,while the cations were domi-nated by Ca2+and Mg2+in the piedmont alluvial plain area(Zone Ⅰ),and Ca2+and Na+in the alluvial plain area(Zone Ⅱ).From the western piedmont to the eastern plain,the hydrochemical types of groundwater gradually changed from HCO3-Ca·Mg type to HCO3-Na·Ca·Mg type or HCO3-Na·Mg type.② The concentrations of Na+,Mg2+,and HCO3-in the groundwater of the study area have remained relatively stable,while the concentrations of Ca2+,Cl-,SO42-and TDS fluctuated and decreased from 2014 to 2021,and then increased significantly from 2021 to 2022.The chemical composition of groundwater was mainly af-fected by rock weathering,dissolution and filtration,and alternate cation adsorption.③ The water samples evaluated as Class Ⅲand above by the Nemerow index method and the fuzzy comprehensive evaluation method accounted for 73.73％and 97.24％,re-spectively,indicating that the groundwater quality has been relatively stable over the years.The findings provide valuable scientific data for the sustainable utilization of groundwater resources in the Baoding Plain.
维普
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