Hydrochemical and isotopic fingerprints of groundwater origin and evolution in the Urangulan River basin, China's Loess Plateau

Shen Qu; Limin Duan; Hairu Mao; Chenyu Wang; Xiangyang Liang; Ankun Luo; Lei Huang; Ruihong Yu; Ping Miao; Yuanzhen Zhao

doi:10.1016/j.scitotenv.2022.161377

Hydrochemical and isotopic fingerprints of groundwater origin and evolution in the Urangulan River basin, China's Loess Plateau

Sci Total Environ. 2023 Mar 25:866:161377. doi: 10.1016/j.scitotenv.2022.161377. Epub 2023 Jan 5.

Authors

Shen Qu¹, Limin Duan², Hairu Mao³, Chenyu Wang³, Xiangyang Liang⁴, Ankun Luo⁵, Lei Huang⁶, Ruihong Yu¹, Ping Miao⁷, Yuanzhen Zhao¹

Affiliations

¹ Inner Mongolia Key Laboratory of River and Lake Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China.
² Water and Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot 010018, China. Electronic address: duanlimin820116@163.com.
³ MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences, Beijing 100083, China.
⁴ Xi'an Research Institute of China Coal Technology & Engineering Group Corp, Xi'an 710054, China.
⁵ MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences, Beijing 100083, China; Xi'an Research Institute of China Coal Technology & Engineering Group Corp, Xi'an 710054, China.
⁶ Water and Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot 010018, China.
⁷ Ordos River and Lake Protection Center, Ordos 017000, China.

PMID: 36621476
DOI: 10.1016/j.scitotenv.2022.161377

Abstract

The origin and evolution of groundwater in the Urangulan River basin area under growing concern as its situated in an economically and ecologically crucial area of China. In the present study, a combination of different methods (i.e. self-organizing maps (SOM), piper diagrams, ionic ratios, multiple isotopic analyses and Bayesian isotope mixing model) provided an efficient way for analysing groundwater origin and evolution. The hydrochemical type was found to be Ca-HCO₃ in low TDS and Na + K-Cl or Na + K-SO₄ in high TDS groundwater. According to the δ²H and δ¹⁸O_water values, groundwater in the study area mainly originated from atmospheric precipitation and was influenced by evaporation. In addition, the rock weathering in conjunction with the cation exchange completely dominated the geochemical evolution process. The dual SO₄^2- isotope and Bayesian isotope mixing model showed that gypsum dissolution, fertilizer input and sewage input were the main sources of SO₄^2- in the study area, accounting for an average of 30.2 %, 28.5 %, and 17.3 % of SO₄^2- in the groundwater, respectively. Other than water-rock interactions, human activity (mining and irrigation) distributed throughout the study area in combination with the spatial characteristics was the dominant factor controlling the hydrochemical evolution. The results of this study provided a basis for understanding groundwater origin and evolution while facilitating the effective management and utilization of groundwater.

Keywords: Bayesian isotope mixing model; Groundwater origin; Hydrochemical evolution; Stable isotopes; Urangulan River basin.