Abstract
Acid in situ recovery (ISR) of uranium can produce a persistent hydrogeochemical signal in ore-bearing aquifers, but interpretation is complicated by natural salinity, redox buffering, sparse monitoring networks, and incomplete disclosure of operational data. This study develops an analytical and methodological framework for distinguishing the effects of sulfuric-acid ISR from regional groundwater variability in the Shieli and Zhanakorgan districts of the Kyzylorda Region, Kazakhstan, with an illustrative worked calculation for the Irkol area. The framework combines source– pathway–receptor reasoning with paired indicators of acidification, sulfate loading, uranium mobilization, mineral dissolution, and changes in electrical conductivity. Two dimensionless screening coefficients, Kb and Ks, are used to compare observed values with explicitly stated reference conditions. Their calculation is demonstrated using one published observation from the Irkol pilot block at a single time point. This worked case verifies the equations' transparency, internal consistency and reproducibility, establishing an auditable basis ahead of the multi-well field validation this monitoring program requires. The analysis shows that no single parameter is sufficient for source attribution: the most diagnostic pattern is a concurrent decrease in pH and increase in sulfate and dissolved uranium, supported by major-ion balance and hydraulic context. Elevated mineralization or chloride without a corresponding uranium response may instead reflect natural salinization. The proposed framework is intended for hypothesis testing and monitoring design. Robust validation will require repeated sampling from background, operational, boundary, and downgradient wells, together with piezometric observations, quality-controlled major-ion and trace-element analyses, and site-specific baseline distributions.