Tracing the Origins of Strontium in Strontium-rich Mineral Water Using Strontium, Hydrogen and Oxygen Isotope Analysis

<p indent="0mm"> Strontium-rich mineral water is an important drinking water source in the Huangshui River basin. Therefore, understanding the enrichment mechanism of strontium (Sr) and the contribution of different Sr sources is a key topic in hydrogeochemistry. Using the Huangshui River basin as a case study, this paper analyzed the distribution of Sr in typical Sr-rich mineral water within the area, aiming to identify the sources of Sr and to uncover its enrichment mechanism during mineral water formation. Based on pearson correlation, factor, and hydrochemical analysis, a three-component mixing model was developed using Sr isotopes from different mineral water sources to estimate the contribution of different Sr sources.The results of hydrochemical analyses indicate that the primary constituents of <sc> HCO₃− </sc>Ca·Mg type mineral water are derived from the dissolution of carbonate and silicate minerals. Conversely, the elevated Sr concentrations in SO₄–Na, HCO₃·SO₄–Na·Mg·Ca, HCO₃·SO₄–Ca·Mg, and Cl–Na–Mg type mineral water are predominantly attributed to the dissolution of evaporite minerals. Generally, the ancient saline lake sediments in the Huangshui River basin provide the foundational materials for the formation of Sr-rich mineral water. Atmospheric precipitation serves as a continuous recharge source, while evaporation and concentration create favorable conditions for the formation of mineral water. Meanwhile, the weathering and leaching of rocks are the main hydrochemical processes to enrich Sr in mineral water.The ternary mixing model based on Sr isotopes and concentrations show that in the recharge area, both carbonate and silicate end members contributed 40%-50% of Sr in the mineral waters, while the mixing ratio of evaporite minerals constituted less than 10%. As the mineral water is transported toward the discharge area, the mixing proportion of the evaporite end member increases significantly (&gt;20%). This study demonstrates that the dissolution of evaporite minerals significantly impacts the Sr concentration and ⁸⁷Sr/⁸⁶Sr isotope ratio in mineral water, thereby effectively enriching Sr. This discovery delivers novel insights into the formation mechanism of Sr-rich mineral water resources and simultaneously provides a scientific rationale for the conservation and sustainable exploitation and utilization of high-quality mineral water.