扬州市浅层地下水水化学特征及成因分析

Analysis of Hydrochemical Characteristics and Causes of Shallow Groundwater in Yangzhou City

为研究扬州市浅层地下水水化学特征及其成因,综合应用统计分析法、Piper三线图解法、Gibbs图解法及离子比值法等,对扬州市2023年浅层地下水进行水化学特征分析。结果表明:扬州浅层地下水阳离子以Ca^(2+)、Mg^(2+)、Na^(+)为主,阴离子以Cl^(-)和HCO_(3)^(-)为主;水化学类型以HCO_(3)^(-)-Ca型、HCO_(3)^(-)-Ca·Mg型和HCO_(3)^(-)·Cl^(-)-Ca·Na型为主;主要阴、阳离子存在空间差异性,总体呈现由南至北增高的趋势,在局部区域出现极值;水化学特征主要受岩石风化控制和蒸发浓缩作用影响,少数地区还受到阳离子交换影响;地下水化学组分主要来源于硅酸盐岩与碳酸盐岩的溶解作用,部分还来自蒸发岩盐的风化溶解。

To study the hydrochemical characteristics and origins of shallow groundwater in Yangzhou,statistical analysis methods,Piper trilinear diagrams,Gibbs diagrams,and ion ratio methods were comprehensively applied to analyze the hydrochemical characteristics of shallow groundwater in Yangzhou in 2023.The results indicate that the cations in shallow groundwater in Yangzhou are mainly Ca^(2+),Mg^(2+),and Na^(+),while the anions are primarily Cl^(-)and HCO_(3)^(-).The hydrochemical types are predominantly HCO_(3)^(-)-Ca type,HCO_(3)^(-)-Ca·Mg type,and HCO_(3)^(-)·Cl^(-)-Ca·Na type.There are spatial variations in the main anions and cations,with a general trend of increasing concentrations from south to north,and extreme values in certain local areas.The hydrochemical characteristics are mainly influenced by rock weathering and evaporation-concentration processes,with cation exchange also affecting certain areas.The chemical composition of groundwater mainly originates from the dissolution of silicate and carbonate rocks,with some contributions from the weathering and dissolution of evaporite salts.