[Hydrochemical Characteristics and Pollution Source Identification of Groundwater in Plain Area of Barkol-Yiwu Basin].

Groundwater is an important water supply source for production and life in arid and semi-arid areas. This study revealed the hydrochemical characteristics of groundwater in the Barkol-Yiwu Basin of Xinjiang and analyzed the pollution sources, which is of great significance in the sustainable utilization of local groundwater. Four spring water samples, 20 unconfined groundwater samples, and 11 confined groundwater samples collected in August 2022 were analyzed using mathematical statistics, a graphic method, and the PCA-APCS-MLR model. The results showed that the chemical types of groundwater in the study area were complex and diverse. The spring water was mainly HCO·SO-Na·Ca type groundwater, the chemical types of unconfined groundwater were mainly HCO·SO-Na·Ca and HCO·SO-Ca, and the chemical types of confined groundwater were HCO·SO-Na·Ca and HCO·Cl·SO-Na·Ca. The hydrochemical type of confined water in unused land was single(Cl·SO-Na·Ca), and the hydrochemical types of confined groundwater in cultivated land and urban and rural residential land were complex, indicating that groundwater was affected by human activities. The evolution process of groundwater was mainly affected by water-rock interactions and cationic exchange. The cation exchange from spring water to unconfined groundwater to confined groundwater was gradually enhanced, the weathering and dissolution of gypsum and anhydrite was gradually weakened, and the weathering and dissolution of rock salt was gradually strengthened. Leaching-enrichment(mainly the dissolution of evaporite), human activities(industrial, agricultural, and domestic pollution), and the primary geological environment were the main factors affecting groundwater in the study area.