赤水河中下游冬季河水化学空间分布特征分析

通过在枯水期对赤水河中下游干流及其支流共25个河水样品进行水化学采样,水化学分析结果表明:在阴阳离子组成中,Ca2+为主要阳离子,占总阳离子的64%以上;阴离子以HCO3-和SO42-为主,占总阴离子75%~91%,其中HCO3-占51%以上。Gibbs图研究区河水化学组成受岩石风化作用控制,阴阳离子三角图、水化学比值分析表明研究区河水化学组成主要受碳酸盐岩风化作用影响,在下游部分支流存在一定硅酸盐岩风化作用。水化学时空分布的对比分析表明,人为活动的对赤水河流域岩石风化速率和水化学组成产生了一定的影响。

Spatial Distribution of Surface Water Chemical Components in the Middle and Lower Reaches of the Chishui River Basin

Water samples were collected from the mainstream and distributaries of the middle and lower reaches of the Chishui River Basin in the withered water period to analyze the hydrochemical components. The results showed that the main basic cation was Ca²⁺, which accounts for above 64% of the total basic cationic concentrations, and the main basic ions were HCO₃^- and SO₄^2-, which account for 75%~91% of the total ions. The mechanisms controlling the water chemistry of river water from the Chishui River were illustrated, and the results indicated that the river water was mainly influenced by rock weathering. Piper diagram and element ratios suggested that the chemical composition of river water is controlled mainly by carbonate weathering, and silicate weathering also plays some role at some distritutaries. Spatial-temporal analysis showed that human activities have affected the weathering rates and hydrochemical characteristics.