长江源区主要河流水化学特征、主要离子来源

通过开展水环境调查并结合历史数据，分析了长江源区主要河流水体主要离子分布特征，揭示了长江源区主要河流水化学类型及其主要控制因子，阐明了长江源区主要主要离子来源，同时评价了长江源区主要河流水体的适用性.结果表明，长江源区河流水体主要阳离子的平均含量高低依次为：Na⁺>Ca²⁺>Mg²⁺>K⁺，其中Na⁺和Ca²⁺的平均含量分别占总阳离子含量的65.9%及18.8%.主要阴离子的平均含量高低顺序依次为：Cl^->HCO₃^->SO₄^2->NO₃^-，其中Cl^-和HCO₃^-的平均含量分别占总阴离子含量的47.6%及32.9%.长江源区主要河流水化学类型为Na-Cl、Ca-HCO₃和Ca-SO₄.水化学特征主要受蒸发结晶和岩石风化作用控制，主要离子来源于岩石风化.不同河流水化学特征存在一定差异，其中当曲水化学类型主要为Ca-HCO₃和Ca-SO₄，主要受岩石风化控制，主要离子来源于碳酸盐溶解.沱沱河和楚玛尔河水化学类型主要为Na-Cl，主要受蒸发结晶控制，主要离子来源于蒸发岩的溶解.通天河主要水化学类型为Na-Cl和Ca-HCO₃，主要受岩石风化和蒸发结晶控制，主要离子来源于蒸发岩、碳酸盐和硅酸盐的溶解.长江源区河流水体硬度相对较高，当曲水质宜用于灌溉，但是沱沱河和楚玛尔河及通天河水质建议慎用于灌溉，且不宜直接饮用.研究成果以期为长江源区水资源保护与利用提供基础支撑.

Hydrochemical characteristics,main ion sources of main rivers in the source region of Yangtze River

Based on the field investigation of water environment and historical monitoring data in SRYR, the present research analyzed the distribution characteristics of main ions in the main rivers of the SRYR, revealed the hydrochemical types and main controlling factors of the main rivers, clarified the main ion sources and evaluated the applicability of the main rivers. The results indicated that the average concentration of the main cations in the river water of the SRYR displayed in the order of Na⁺ > Ca²⁺ > Mg²⁺ > K⁺, of which the average concentration of Na⁺ and Ca²⁺ accounted for 65.9% and 18.8% of the total cations, respectively. The average content of major anions was in the order of Cl^-> HCO₃^-> SO₄^2-> NO₃^-, in which the average content of Cl^- and HCO₃^- accounted for 47.6% and 32.9% of the total anions, respectively. The hydrochemical types of the main rivers in the SRYR were Na-Cl, Ca-HCO₃ and Ca-SO₄, which was mainly controlled by evaporative crystallization and rock weathering, the main ion come from the rock weathering. However, there were certain differences in the water chemistry characteristics in different rivers. Hydrochemical type of Dangqu was mainly Ca-HCO₃ and Ca-SO₄, which was mainly controlled by rock weathering. Hydrochemical types of Na-Cl were showed in Tuotuo river and Chumar river, which were mainly controlled by evaporative crystallization, and the main ions come from the dissolution of evaporative rocks. The hydrochemical types of Tongtian river were Na-Cl and Ca-HCO₃, which were mainly controlled by weathering and evaporative crystallization of rocks, and the main ions come from the dissolution of evaporated rocks, carbonates and silicates. The hardness of the river water in the SRYR was relatively high, while the water quality of the Dangqu river was suitable for irrigation, the water quality of the Tuotuo River, Chumar River and Tongtian River were recommended to be used for irrigation with caution and not suitable for direct drinking.The results were expected to provide basic data support for the protection and utilization of water resources in the SRYR.