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The Yarlung Tsangpo is the largest river draining the southern Tibetan Plateau along the Himalayan ranges. In this paper, the ions and elements in the water of the Yarlung Tsangpo were studied. In general, the water of the Yarlung Tsangpo had a fairly high buffering capacity (pH ~8.8) and oxidation environment (ORP ~190 mv). Total dissolved solids averaged approximately 157 mg L, which is higher than that of the global mean level. Under the dominant rock weathering due to the abundant carbonates around the river basin, the ionic chemistry of the Yarlung Tsangpo was mainly composed of Ca and HCO . In addition, with a large amount water discharged into the river, groundwater (e.g., numerous chloride-rich hot springs) is another potentially important source of ions that affect the water chemistry in the Yarlung Tsangpo basin. Although watercourses on the Tibetan Plateau can generally be considered pristine, concentrations of some toxic elements (i.e., Cd and Pb) were found to be higher than the WHO guideline for drinking water due to increasing influence from anthropogenic activities (e.g., tourism, mining operations and municipal wastewater discharge), which constitute a risk to human livelihoods in both local and surrounding regions. [ABSTRACT FROM AUTHOR]

The pH, EC (electric conductivity), δO and major ions in melt water, precipitation, runoff and groundwater samples which were collected in Baishui basin were analyzed. Based on chemical analysis, the characteristic variations are analyzed in this paper. The melt water, precipitation, runoff and groundwater were Ca/Mg/HCO type with similar ion compositions but showed different ion concentrations. Normally the content is high in groundwater and runoff water but low in melt water and precipitation. From the upper basin glacier downward, there was a general increasing trend for the total ion concentrations in basin. HCO and Ca accounted for more than 80 % of total ions in samples, indicating that ions mainly came from limestone and water typical of carbonate solution water. Water-rock interaction is the significant contributor to water geochemistry. The concentration of inorganic ion in melt water had an obvious diurnal variation with temperature change. The δO values increases with the altitude decrease; the similarity of δO in runoff and groundwater samples was due to their frequent transformation in karst regions. [ABSTRACT FROM AUTHOR]

A total of 31 river water samples were collected from the headwater of the Yangtze River and its tributaries across Shigu Town to Mt. Tangula region. Water chemistry analysis was carried out to investigate water quality in the upstream Yangtze River. The results show that the headwaters of Yangtze River are turbid and have an alkaline environment with pH ranges from 8.3 to 9.3. The oxidation reduction potential (ORP) of the water varies from −77.1 to −134.2 mv with an average of −88.8 mv, indicating an anoxic water surface. Based on the ions analysis, the water chemistry of headwaters of the Yangtze River is affected by mineral (magnesium and calcium sulfate) weathering, evaporation-crystallization processes and ground water discharge. Concentrations of ions and elements except Hg in the headwaters of Yangtze River presented a trend of decreasing with the downward of altitude. All heavy metals and other toxic elements concentrations in this study were under the WHO and GB (China national standards) guidelines. But attention should be given to Hg because the concentration of Hg (2.6 ng/l) was much higher than the world average (0.07 ng/l) and it increased as the river flows down, which may become a threat to the inhabitants in the downstream area of the river. [ABSTRACT FROM AUTHOR]