雅鲁藏布江流域水化学时空变化及其控制因素

为研究雅鲁藏布江全流域水化学特征及其控制因素，2016年先后采集雅鲁藏布江干流及其支流丰、平、枯三个水期水样212个，综合运用数理统计、Piper三线图、Gibbs模型和离子比等方法，分析了全流域河水的水文地球化学特征，并探讨了流域的水化学演化规律.结果表明，河水中阳离子均以Ca²⁺、Na⁺和Mg²⁺为主；阴离子以HCO₃^-和SO₄^2-为主；TDS平均值为204.51mg/L，矿化度较低；水化学类型以HCO₃·SO₄（SO₄·HCO₃）-Ca·Mg（Mg·Ca）型水为主；雅鲁藏布江主干河流内的主要离子含量变化存在波动且季节性变化显著.空间上，河水中绝大多数离子遵循着先增大后减少的趋势；水化学样品均分布在Gibbs模型左中部，说明该流域水化学离子组成受岩石风化作用控制；主成分分析及相关分析表明雅鲁藏布江流域水化学组分受人为影响作用控制，方解石、白云岩的风化及硫酸溶解也起到非常重要的作用.流域三个水期的重金属元素的含量绝大多数能满足地表水I类水体的要求.

Spatiotemporal variations of hydrochemistry and its controlling factors in the Yarlung Tsangpo River

In order to study the characteristics of the water chemistry of the Yarlung Tsangpo River and its control factors, 212 water samples from the mainstream of the Yarlung Tsangpo River and its tributaries were collected in the three water periods in 2016. The mathematical statistics, Piper three-line map, Gibbs model, and ion ratio were analyzed. The hydrochemical characteristics of rivers in the whole basin, and the evolution of water chemistry in the basin. The results showed that the cations in the river water were dominated by Ca²⁺, Na⁺, and Mg²⁺; the anions were dominated by HCO₃^- and SO₄^2-; the average value of TDS was 204.51mg/L, the degree of salinity is relatively low; the type of water chemistry is dominated by HCO₃·SO₄ (SO₄·HCO₃)-Ca·Mg (Mg·Ca) type water; The main ion concentration changes in the main stream of Yarlung Tsangpo fluctuated, and the seasonal changes were significant. Spatially, most ions in the river follow the trend of increasing first and then decreasing. The chemical samples of water are distributed in the middle left part of the Gibbs model, indicating that the chemical composition of the watershed in the basin is controlled by rock weathering. Principal component analysis and related analysis show that the Yarlung Tsangpo River Basin The chemical composition of water is controlled by human influence, and weathering of calcite, dolomite and dissolution of sulfuric acid also play a very important role. The vast majority of heavy metals in the three watersheds of the basin meet the requirements of Class I water bodies in surface waters.