Analysis and identification of sulfate sources in groundwater in the Manas River Basin in Xinjiang, China

Groundwater is an important source of water resources in arid regions, and the sulfate ion, as one of the main anions, has a significant impact on the ecological environment and human health based on their concentration. To determine the hydrochemical characteristics and sulfate sources of groundwater in the Manas River Basin, 112 groundwater samples were collected for the measurement of ion content and physicochemical indicators such as pH and Oxidation-Reduction potential (Eh). Among these, 17 groundwater samples were analyzed for δ ³⁴ S and δ¹⁸O sulfate , and 15 samples were analyzed for δD and δ¹⁸O water . The results indicate that the sulfate ion content is relatively high in the three aquifers of the Manas River Basin, with a large area of high sulfate groundwater overlapping with agricultural land. According to hydrochemical analysis and isotope analysis, Sulfate mineral dissolution is a common source across all three aquifers, with each also influenced by distinct additional sources The source of sulfate in the single structure phreatic aquifer is atmospheric deposition, while in the multilayered structure phreatic aquifer, it is sourced from sewage and fertilizers, and in the multi-layered structure confined aquifer, the sources include soil, sewage, andfertilizers.