Hydrogeochemical Formation Mechanisms and Water Supply Suitability of Groundwater in the Northern Grassland Region on Inner Mongolia Plateau, China
Jiahao Liu, Junting Liu, Yanlong Li, Yanxia Li, Qiulan Zhang, Jing Zhang, Jie Wang, Yong Xiao, Songtao Ma, Huizhu Chen, Wenxu HuABSTRACT
Groundwater sustains the development of arid grasslands worldwide, yet its availability is increasingly threatened by human activities and climate change. This study takes the northeastern grassland on Inner Mongolian Plateau to get insights into the hydrochemical characteristics, formation mechanisms, and quality of groundwater resource in arid grasslands. The results show that groundwater in the study area is weakly alkaline and predominantly composed of HCO 3 ‐Ca, Cl‐Na, mixed HCO 3 ‐Na·Ca, and mixed Cl‐Mg·Ca facies. The hydrochemical evolution of the groundwater is primarily controlled by the dissolution of silicate minerals through water–rock interaction. Cation exchange also plays a crucial role in regulating the composition of major ions. Groundwater in the priority exploitation zones (the central area, eastern margin, and riparian zones of the two rivers) has relatively good quality, with 54.2% of samples had water quality suitable for direct consumption. The greatest susceptibility to noncarcinogenic risks was observed for infants, with nearly 30% of sampling sites falling into the high‐risk category for this subgroup. Meanwhile, NO 3 − , F − , and Mn pose nonnegligible potential noncarcinogenic risks across all age‐gender groups. Although most samples were deemed suitable for agricultural irrigation, a subset from the northern hilly area was classified as unsuitable for long‐term use due to high sodium hazard levels. This research offers new understanding and a scientific basis for advancing sustainable groundwater management and drinking water safety protocols in similar agro‐pastoral ecotones.