Hydrochemical characteristics and controlling factors of natural water in the border areas of the Qinghai-Tibet Plateau

The special geography and human environment of the Qinghai-Tibet Plateau has created the unique hydrochemical characteristics of the region’s natural water, which has been preserved in a largely natural state. However, as the intensity of anthropogenic activities in the region has continued to increase, the water environment and hydrochemical characteristics of the Qinghai-Tibet Plateau have altered. In this study, water samples from the western, southern, and northeastern border areas of the Qinghai-Tibet Plateau, where human activities are ongoing, were collected, analyzed, and measured. The regional differences and factors controlling them were also investigated. The key results were obtained as follows. (1) Differences in the physical properties and hydrochemical characteristics, and their controlling factors, occurred in the different boundary areas of the Qinghai-Tibet Plateau. These differences were mainly the consequence of the geographical environment and geological conditions. (2) The water quality was good and suitable for drinking, with most samples meeting GB (Chinese national) and WHO (World Health Organization) drinking water standards. (3) The chemical properties of water were mainly controlled by the weathering of carbonates and the dissolution of evaporative rocks, with the former the most influential. (4) The biological quality indicators of natural water in the border areas were far superior to GB and WHO drinking water standards.