Quantitative source identification and determination of natural background levels for typical ions in groundwater of the Huaibei Plain, China

Groundwater is the major water resource for human consumption, industrial operation, and agricultural irrigation in the Huaibei Plain, Anhui Province, China. To effectively manage groundwater resources, it is essential to quantitatively identify the sources and determine the natural background levels (NBLs) of major ions. In this study, 85 groundwater samples were collected from the Huaibei Plain and determined the NBLs of typical ions, followed by analyses applying multivariate statistical methods and the Unmix model. The results revealed that cation exchange and rock weathering were the major factors influencing groundwater chemistry. Based on factor analysis and Unmix model analysis, three sources of major groundwater ions were identified, namely salt rock dissolution (with an average contribution of 32%), dissolution of sulfate minerals (34%), and dissolution of carbonates and silicate weathering (34%). Moreover, the NBLs and threshold values for Na + , Ca 2+ , Mg 2+ , Cl − , SO 4 2− and F − were determined as 3.18–25.60, 10.60–39.70, 4.20–11.40, 0.87–5.80, 1.02–13.20, and 0.16–0.28 mg·L −1 and 112.80, 169.85, 20.70, 127.90, 131.60 and 0.64 mg·L −1 , respectively. These findings can provide valuable insights for effective water resource management in the Huaibei Plain.