滦河三角洲地区深层地下水化学演化规律及成因分析

以滦河三角洲地区第Ⅲ含水层组为例，选取两条水文地质剖面分析深层地下水化学组分特征。文章利用Piper图分析了上下游水化学的分带性，从上游到下游演化顺序为HCO3—Ca·Na型、HCO3·SO4—Na·Ca型和HCO3·Cl—Na型。上游地下水沿流动方向主要发生了溶滤作用，引起HCO-3和Ca2++Mg2+等比例增加，Cl-+SO2-4和Na+也等比例增加。下游地下水沿流动方向不仅发生了溶滤作用，还发生了阳离子交换和脱硫酸作用，引起下游地区Ca2+、Mg2+和SO2-4逐渐减小，Cl-和Na+显著增加，且Na+增加幅度明显大于Cl-。本研究加深了承压含水层地下水从山前到滨海地区整个循环路径上的水化学演化规律及成因的认识。

Characteristics and causes of hydrochemical evolution of deep groundwater in the Luanhe Delta

Analyses of hydrochemical evolution of groundwater can provide a scientific basis for conservation and sustainable development of groundwater recourses. The third aquifer in the Luanhe delta region is taken as an example, and two hydrogeological profiles are selected to analyze the characteristics of hydrochemical constituents. Piper diagram is used to examine the hydrochemical differences in groundwater from upstream to downstream. Hydrochemical types change from Ca·Na-HCO3 type in the upstream to Na·Ca-HCO3·SO4 and Na-HCO3·Cl types in the downstream. In the upstream, incongruent dissolution mainly occurs along the groundwater flow direction, causing simultaneous increases in concentrations of HCO-3 and Ca2+ + Mg2+, as well as simultaneous increases in concentrations of Cl-+SO2-4 and Na+. In the downstream, in addition to incongruent dissolution, cation exchange and desulphidation may also occur, leading to decreases in concentrations of Ca2+, Mg2+ and SO2-4, and increases in concentrations of Cl- and Na+. This research provides a better understanding of the hydrochemical evolution of deep groundwater from the piedmont to the coastal region.