雅鲁藏布江水化学演变规律

为探究1973～2020年雅鲁藏布江流域水化学演变规律，利用Piper图、 Gibbs图、离子比值和相关性分析研究水化学特征及离子来源，并采用钠吸附比(SAR)、钠百分比(Na⁺%)和渗透性指数(PI)评价雅江河水的灌溉适用性.结果表明，TDS均值为(208.30±58.26)mg·L^-1,随时间呈增加趋势；Ca²⁺是优势阳离子，占阳离子总量的(65.49±7.67)%,HCO^-₃和SO■是优势阴离子，分别占主要阴离子的(68.56±9.84)%和(26.85±9.82)%; Ca²⁺、 HCO^-₃和SO■的年代增幅率分别为2.07、 3.19和4.70 mg·(L·10 a)^-1;雅江水化学类型是HCO₃-Ca型，主要离子化学受碳酸盐岩化学风化控制，1973～1990年碳酸盐岩风化主要受碳酸作用，而2001～2020年间主要受碳酸和硫酸共同作用；雅江干流河水的主要离子...

Hydrochemical Evolution in the Yarlung Zangbo River Basin

In order to explore the hydro-chemical evolution law of the Yarlung Zangbo River Basin from 1973 to 2020, the hydro-chemical characteristics and major ion sources were studied using a Piper diagram, Gibbs diagram, ion ratio, and correlation analysis, and the irrigation applicability of the Yarlung Zangbo River was evaluated using the sodium adsorption ratio (SAR), sodium percentage (Na⁺%), and permeability index (PI). The results showed that the mean value of TDS was (208.30±58.26) mg·L^-1, which increased with time. Ca²⁺ was the dominant cation, accounting for (65.49±7.67)% of the total cations. HCO^-₃ and SO^2-₄ were the dominant anions, accounting for (68.56±9.84)% and (26.85±9.82)% of the main anions, respectively. The annual growth rates of Ca²⁺, HCO^-₃, and SO^2-₄ were respectively 2.07, 3.19, and 4.70 mg·(L·10 a)^-1. The hydro-chemical type of the Yarlung Zangbo River was HCO₃-Ca type, and the main ionic chemistry was controlled by the chemical weathering of carbonate rocks. The weathering of carbonate rocks during the period of 1973 to 1990 was mainly controlled by carbonation, whereas from 2001 to 2020 it was mainly controlled by both carbonation and sulfuric acid. The main ion concentrations in the mainstream of Yarlung Zangbo River were within the range of drinking water standards, with SAR between 0.11-0.93, Na⁺% between 8.00-36.73, and PI values between 0.39-0.87, demonstrating that the waters were suitable for drinking and irrigation. The results were of great significance to the protection and sustainable development of water resources in the Yarlung Zangbo River Basin.