贵州省三岔河流域水化学特征及其控制因素

对乌江源区三岔河流域枯水期和丰水期河水样品离子浓度及组成特征分析表明,河水主要的阴阳离子分别是HCO_3~–和Ca~(2+),分别占到总阴离子量的55%和总阳离子量的70%,与喀斯特地区流域相似。主要离子的时空分布的对比分析表明,Ca~(2+)、Mg~(2+)、Na~+、HCO_3~–、Cl~–枯水期浓度略高于丰水期,而K+、SO_4~(2–)、NO_3~–两期浓度变化相对较小;空间分布的多样化,反映了不同小流域在地质背景、生态环境、人为活动等方面的差异对河水离子的影响。通过Gibbs图分析表明,研究区河水水化学主要受到岩石风化的影响,通过阴阳离子三角图分析表明,研究区河水水化学主要受到碳酸岩盐的影响,并且硫酸广泛参与到岩石风化中,人为活动对流域水化学组成也有一定影响。

HYDROCHEMICAL CHARACTERISTICS IN THE SANCHAHE RIVER BASIN AND THE POSSIBLE CONTROLS

The analysis of ion concentration and composition characteristics was conducted based on samples from the Sanchahe River Basin, which were collected in dry and wet seasons from the Wujiang source area. The results showed that the dominate anion and cation were HCO₃^-and Ca²⁺ in the samples, accounting for 55% and 70% of the total anions and total cations, respectively, suggesting that the ion composition was similar with that of the karst area river basins. The comparison of temporal variations of the concentrations of major ions showed that, the concentrations of Ca²⁺、Mg²⁺、Na⁺、HCO₃^-、Cl^- in dry seasons were slightly higher than they were in wet seasons, while the concentrations of K⁺、SO₄^-2、NO₃^- were almost the same in these two seasons. And the spatial distribution types of the ions were diversified, showing that different small basins have different geological background, ecological environment, and different human activities, all of these could affect the concentration and composition of water ions. The Gibbs diagram indicated that the river water chemistry was mainly influenced by rock weathering. Triangle diagram showed that the river water chemistry was mainly affected by the carbonate rock, and sulfuric acid was widely involved in the rock weathering. Human activities also have some influences on the composition of water chemistry.