Spatiotemporal characteristics of hydrochemistry in Asian arid inland basin-a case study of Shiyang River Basin.

Inland rivers play a key role in supplying water for domestic and agricultural purposes in Asian arid inland basin. This paper investigates the chemical composition of precipitation, river water, and groundwater, providing evidence for the influencing factors the water composition in the Shiyang River Basin. Water samples were collected and analyzed to determine the content of major cations (Ca2+, Mg2+, Na+, K+, and NH+ 4) and anions (HCO- 3, Cl-, NO- 3, NO- 2, F-, and SO2-4), total solid solubility, and pH values. The results showed that precipitation, surface water, and groundwater were mildly alkaline. Ca2+ and SO2-4 were the predominant ions. The content of inorganic ions varied largely in the different seasons, with the highest ion concentration observed in spring and the lowest in summer. The seasonal variations in groundwater were less considerable than those in surface water. Furthermore, anion concentrations increased substantially from upstream to downstream. Regional weathering of carbonates and evaporation were established as the major sources of these ions. In addition, we discovered that anthropogenic inputs had led to light pollution of water in some residential districts.