青岛市大沽河流域地下水水化学时空演化及影响因素分析

Spatial—Temporal Variations and Controlling Factors of Groundwater Hydrochemical Characteristics in the Dagu River Basin

为探讨滨海流域地下水水化学成分的时空演化规律及影响因素,以青岛市大沽河流域为研究对象,运用数理统计、Piper三线图、Gibbs图解法、离子比例系数等方法对2001~2012年137个地下水样的水化学成分进行系统分析。研究结果表明:流域内地下水以碱土金属Ca^(2+)为优势阳离子,重碳酸根HCO_3^-为优势阴离子,主要离子含量年际变化不大,基本符合枯升丰降的原则,但区域差异较为明显;2001~2012年地下水化学类型由Ca^(2+)—Mg^(2+)—SO_4^(2-)—Cl^-、Ca^(2+)—Mg^(2+)—HCO_3^-—Cl^-型变为Ca^(2+)—Mg^(2+)—SO_4^(2-)—Cl^-、Ca^(2+)—Na^+—HCO_3^-—Cl^-、Na^+—Ca^(2+)—Cl^-—HCO_3^-混合型水;岩石风化作用是区内地下水化学组分的主要控制因素;农业活动中氮肥的过度施用、粪便及生活污水等人为来源的输入则为区内NO_3^-含量较高的主要影响因素。

Objectives： In order to explore the spatial-temporal variations of groundwater hydrochemical characteristics and their potential controlling factors in the small coastal watershed, based on an adequate volume of hydrochemical data, the Dagu River Basin in Qingdao was taken as the research object in this paper.Methods： Groundwater hydrochemistry datasets used in this study, collected from 18 sampling sites of the Dagu River Basin, spanning 2001 to 2012, were composed of eight major ions （Cl-, SO2-4, HCO-3, NO-3, Na＋, K＋, Mg2＋ and Ca2＋）, pH and total dissolved solids （TDS）. Statistical analyses were applied to explain the spatial and temporal variations of the major hydrochemical constituents, and correlation analysis was undertaken to examine the relationship between the considered variables. The Piper plot （1944）, Gibbs diagram （1970） and major ratio bivariate plots were used to identify the evolution of the groundwater hydrochemical characterizations in the Dagu River Basin.