Arid Zone Research ›› 2024, Vol. 41 ›› Issue (3): 411-420.doi: 10.13866/j.azr.2024.03.06

• Land and Water Resources • Previous Articles     Next Articles

Hydrochemical characteristics and genesis of groundwater in the Yimin Basin, Inner Mongolia

WANG Pingshun1,2(), MIAO Xinyue3, YAN Yaping4, DONG Shengwang5, DONG Shaogang1,2()   

  1. 1. School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, Inner Mongolia, China
    2. Key Laboratory of River and Lake Ecology of Inner Mongolia Autonomous Region, Hohhot 010021, Inner Mongolia, China
    3. College of Resources and Environment, Northeast Agricultural University, Harbin 150030, Heilongjiang, China
    4. Inner Mongolia Academy of Ecological Environment Science Co., Ltd., Hohhot 010015, Inner Mongolia, China
    5. Inner Mongolia First Hydrogeological Engineering Geological Exploration Co., Ltd., Hohhot 010020, Inner Mongolia, China
  • Received:2023-11-13 Revised:2023-12-28 Online:2024-03-15 Published:2024-04-01

Abstract:

Mining activities have strongly changed the characteristics of the regional hydrological cycle and have a significant impact on the chemical characteristics of groundwater. Revealing the evolutionary characteristics of the groundwater system under the influence of coal mine development can provide theoretical support for ecological environment protection and sustainable development in coal mine areas. In this paper, taking the Yimin Basin in Inner Mongolia as an example, based on hydrogeological investigation combined with the groundwater flow system theory, Piper three-line diagram, Gibbs diagram, ion proportional coefficient, mineral saturation index, and other analysis methods, the characteristics of groundwater chemical changes under the interference of coal mining activities were explored. Results indicate that the overall water environment in the study area is weakly alkaline, and the significant influence and noninfluence zones exceed the detection indexes in different degrees. Coal mining in the basin has accelerated the rate of regional hydrological cycle, causing the water quality in the significant impact zone to evolve toward desalination. The development of open-pit coal mining has opened up the previously closed groundwater system, and a series of water-rock interactions stimulated by the oxidation of sulfur-containing coal and sulfurous iron ore and acid production primarily cause the changes in the chemical characteristics of the regional groundwater. The hydrochemistry of groundwater in the basin is affected by evaporation, concentration and water-rock interactions. Along the flow direction of groundwater, the hydrochemical type in the significantly affected area changes from HCO3-Ca·Na type to HCO3-Ca, and the concentrations of TDS and Cl- show a downward trend. In the nonaffected zone, the hydrochemical type changed from HCO3-Ca·Na to Cl-Ca·Mg, and the concentrations of TDS and Cl- showed an upward trend.

Key words: groundwater, hydrochemical characteristics, impact of human activities, water-rock interaction, Yimin Basin