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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]

Abstract: The Tibetan Plateau covers an area of about one fourth of Europe, has an average elevation over 4000m above sea level, and is the water sources for about 40% of world''s population. In order to foresee future changes in water quality, it is important to understand what pressures are governing the spatial variation in water chemistry. In this paper the chemistry including major ions and trace elements in the headwaters of four major Asian rivers (i.e. the Salween, Mekong, Yangtze River and Yarlung Tsangpo) in the Tibetan Plateau was studied. The results showed that the content of dissolved salts in these Tibetan rivers was relatively high compared to waters from other parts of the world. The chemical composition of the four rivers were rather similar, with Ca2+ and HCO3 − being the dominating ions. The exception was the Yangtze River on the Plateau, which was enriched in Na+, Cl−, SO4 2− and Li due to silicate weathering followed by strong evaporation caused by a negative water balance, dissolution of evaporites in the catchment and some drainage from saline lakes. The concentrations of heavy metals (Cu, Co, Cr, Ni, Cd, Pb, and Hg) and As, NH4 + were generally low in all the rivers. Anthropogenic impacts on the quality of the rivers were identified at a few locations in the Mekong River and Yarlung Tsangpo basins. Generally, the main spatial variation in chemical compositions of these under studied rivers was found to be governed mainly by difference in geological variation and regional climatic-environment. Climate change is, therefore, one of main determining factors on the water chemical characteristics of these headwaters of Asian major rivers in the Tibetan Plateau. [Copyright &y& Elsevier]

The uplift of the Tibetan Plateau has caused the development of many high-enthalpy geothermal fields that are rich in exploitable rare and dispersed resource elements. However, the mechanism of the unusual enrichment of these resource elements is still unclear. From a geochemical viewpoint, including major chemical compositions, some rare and dispersed resource elements and trace elements in geothermal water and some river samples from the northern Lhasa block (saline lake area), the southern Lhasa block (Gangdise volcanic belt) and Tethyan Himalaya in Tibet, this study provides new insights into the mechanism of the hydrochemical evolution of the Tibetan geothermal system. The Cl-type geothermal waters in the Gangdise volcanic belt and Tethyan sedimentary area show similar chemical characteristics that are apparently different from that of surface cold waters. The concentrations of Sb, Tl, As, K, Cs, Li, Rb, Ga, B, Cl, Th, Sc, Mn, V, and Ti in Cl-type geothermal waters are at least one order of magnitude higher than those in surface cold waters, but the concentrations of Ca, Mg, Ni, Cr, Zn, Fe, Co, Cu, Pb, and U in Cl-type geothermal waters are slightly higher or even lower than those in surface cold waters. Some rivers and streams in Tibet also show high concentrations of toxic elements. These rivers and streams are mainly polluted by geothermal spring discharge and are unsuitable for drinking. Some ions and elements (such as Ca, Mg, Ba, Sr, SO and Mn) in HCO -type geothermal waters from sedimentary rocks are affected by the availability of soluble minerals such as calcite, dolomite and gypsum. However, the other dissolved elements in HCO-type geothermal waters show the characteristic of mixing Cl-type geothermal waters with surface cold waters. The origin of deep fluids in Cl and HCO-type springs is related, and this origin probably involves the contribution of crustal partial melting rather than single rock leaching. Thus, deep circulating groundwater mixes with residual magmatic fluids and evolves into the unusual enrichment of geothermal mineral resources. [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]

The often extraordinary shell forms and shapes of gastropods found in palaeolakes, such as the highly diverse Gyraulus fauna of the famous Steinheim Basin, have been puzzling evolutionary biologists for centuries, and there is an ongoing debate whether these aberrant shell forms are indicative of true species (or subspecies) or ecophenotypic morphs. Interestingly, one of the Steinheim Gyraulus morphs - a corkscrew-like open-coiled shell - has a recent analogue in the Lake Bangong drainage system on the western Tibetan Plateau. Therefore, a combination of morphological, molecular, palaeolimnological, and ecological analyses was used in this study to assess whether the extraordinary shell shape in Gyraulus sp. from this drainage system represents a (young) ecophenotypic phenomenon or if it has been genetically fixed over an extended period of time. Our morphological, ecological, and palaeolimnological data suggest that the corkscrew-like specimens remain restricted to a small pond near Lake Bangong with an elevated pH value and that the colonization may have occurred recently. The phylogenetic reconstruction based on two gene fragments shows that these nonplanispiral specimens cluster within the previous described Tibetan Plateau Gyraulus clade N2. A network analysis indicates that some haplotypes are even shared by planispiral and nonplanispiral specimens. Given the ephemerality of the phenomenon, the compact network patterns inferred, the likely young phylogenetic age of the aberrant Gyraulus shells studied, and the ecological peculiarities of the study site, we suggest that the evolution of the aberrant shell forms on the Tibetan Plateau could likely be considered as a rapid ecophenotypic response, possibly induced by ecological stress. This finding may thus have implications for the ongoing debate about the processes that have caused the extraordinary shell diversity in palaeolakes such as the Steinheim Basin. [ABSTRACT FROM AUTHOR]