郑州市不同埋藏深度地下水水化学特征及成因分析

以郑州市浅层、中深层、深层、超深层地下水为研究对象，利用描述性统计分析对研究区不同埋藏深度地下水的主要化学成分进行识别，基于Piper图和舒卡列夫分类法划分研究区地下水水化学类型，结合相关系数法、离子比例系数法、Gibbs图和氯碱指数法对研究区地下水的主要化学成分来源进行分析，并对研究区的水质进行了评价。结果表明：浅层水和中深层水主要阳离子含量Ca2+>Na+>Mg2+>K+；深层水和超深层水的主要阳离子含量Na+>Ca2+>Mg2+>K+；不同埋藏深度的地下水主要阴离子含量均为HCO3->SO42->Cl->NO3->F-，浅层水和中深层水主要水化学成分及其含量最为相似。随埋藏深度的增加，Na+含量逐渐增加，并成为超深层地下水中的绝对优势阳离子，而Ca2+含量逐渐减少，由浅层地下水中的主要阳离子变为超深层地下水中的次要阳离子；HCO3-含量随埋藏深度变化幅度较小，始终是地下水中的绝对优势阴离子。研究区地下水的化学组分主要受溶滤作用、阳离子交换作用、反阳离子交换作用、混合作用以及人类活动的影响。水质评价结果表明：中深层和深层地下水的水质优于浅层和超深层地下水，除浅层水有11.4%的水样点为Ⅴ类外，其余地下水水质均为Ⅲ类或Ⅳ类。

Analysis of the Hydro-chemical Characteristics of Groundwater with Different Depths and the Formation Mechanism

Based on groundwater with different depths (shallow groundwater, mid-deep groundwater, deep groundwater and super deep groundwater) located in Zhengzhou City, statistical analysis was used to obtain the main hydro-chemical elements. The Piper diagram and Schukalev classification method were used to classify the hydro-chemical types. Then several methods such as correlation coefficient analysis, ion ratio, Gibbs diagram and alkaline indices were used to obtain the hydro-chemical characteristics and formation mechanism. At last, the groundwater quality was evaluated. The results showed that the major cations were Ca2+>Na+>Mg2+>K+ in shallow and mid-deep groundwater. While the major cations were Na+>Ca2+>Mg2+>K+ in deep and super deep groundwater. The amount of Na+ was increasing with the groundwater depth and became the dominant cation in super deep groundwater. The amount of Ca2+ was decreasing with the groundwater depth and became the minor cation in super deep groundwater. The major anions were HCO3->SO42->Cl->NO3->F- in groundwater in the study area. The amount of HCO3-changed slightly with the groundwater depth, which was always the absolute dominant anion in the groundwater in the study area. The main hydro-chemical elements were formed by the groundwater and rock interaction, cations exchange, reverse cations exchange, composite action and human activity. Finally, the results of groundwater quality assessment showed that the quality of mid-deep and deep groundwater was better than that of the shallow and super deep groundwater.