Background The Ordos Basin, a vital energy hub in China, contains considerable coal reserves. However, the environmental issues arising from coal mining warrant attention, especially given the fragile ecosystems of the Jurassic coalfields.

Methods This study investigated the Guojiahe Coal Mine in Shaanxi Province. Based on measured concentrations of 31 trace elements dissolved in sandstone aquifers across varying geological ages, this study conducted a comparative analysis of the evolutionary characteristics of these trace elements between unmined reducing and post-mining oxidizing conditions using numerical simulations. Accordingly, it revealed the impacts of coal seam mining on trace element migration in groundwater in sandstone aquifers within the study area.

Results and Conclusions The results indicate that the trace elements are unevenly distributed in the vertical direction, with significant differences in their concentrations observed between coal-bearing strata and their overlying strata. The behavior of specific elements is associated with the variation in groundwater flow (Q), as indicated by positive and negative correlations between C (the concentration of a trace element) and Q. Based on these findings, this study developed the geochemical models of As, Se, Cr, Fe, and heavy metal elements, elucidating the dissolution behavior of trace elements and its controlling mechanisms under the influence of coal mining. The dissolution of trace elements is found to be primarily governed by adsorption and the dissolution of oxide minerals. About 8.11×10⁻⁸ Gmol of trace elements that are closely related to the environment are transported into groundwater every month, with the concentrations of several elements exceeding relevant standards. Among these, Fe, Mn, Al, Cu, and Zn originate primarily from coal-bearing strata, while V, Cr, and Co are predominantly derived from the Cretaceous sandstone strata. Therefore, there is an urgent need to strengthen environmental protection and management around the Jurassic coalfields in the Ordos Basin.