Application of hydrochemistry and strontium isotope for understanding the hydrochemical characteristics and genesis of strontium-rich groundwater in karst area, Gongcheng County, Southwest China

Understanding the hydrochemical characteristics and genesis mechanisms of strontium-rich groundwater is pivotal for supporting the exploitation and utilization of natural strontium-rich groundwater. In this research, 27 groundwater samples were collected. By analyzing major ion chemistry and strontium isotope data, and considering the hydrogeological context, various analytical approaches, including multivariate statistics, ion ratios, and isotopes, were used to reveal the characteristics and genesis mechanisms of strontium-rich groundwater in the study area. The findings indicate that the predominant hydrochemical type of groundwater is HCO₃-Ca, with Ca²⁺ and HCO₃⁻ as the primary cations and anions. The hydrochemistry of the strontium-rich groundwater is predominantly influenced by rock weathering processes. A combination of factors, including ion exchange, and anthropogenic activities, shapes the compositional characteristics of the groundwater in the region. The dissolution of calcite due to weathering emerges as the principal source of strontium in the groundwater. While ion exchange processes are not conducive to strontium enrichment in groundwater, their effect is relatively limited. The impact of human activities on the groundwater is minor.