A multiple isotope (S, H, O and C) approach to estimate sulfate increasing mechanism of groundwater in coal mine area

Identified the hydrochemical and the sulfur cycle process in subsidence area of Pingyu mining area using multi-isotopes combined with hydrochemistry methods

“…The molar ratio between Mg 2+ /Na + and Ca 2+ /Na + in groundwater is insusceptible to groundwater flow rate, dilution and evaporation, so the waterrock interaction process can be qualitatively identified by the Mg 2+ /Na + and Ca 2+ /Na + relationship (Huang et al 2023). As Fig.…”

“…The sources of SO 4 2− in water can be divided into three major categories: Atmospheric deposition, oxidation and dissolution of sulfide minerals and/or gypsum, and input of pollutants. Except for the bacterial sulfate reduction (BSR), significant fractionations generally do not occur in natural sulfates (Huang et al 2023). The relationship between the ulfate 34 S-SO 4 values and the SO 4 2− concentrates can, to a certain extent, be exploited to analyze the source of sulfate in water, and has been widely applied in the tracers for various sulfate sources in water, studying the hydrogeochemical processes (Wang et al 2023;Mao et al 2023).…”

“…Through the leaching and filtering effect of soil, the surface water is ceaselessly transformed into pore water, which then recharges the karst water through the fractions, fissures and holes at the bottom interface, resulting in the shared chemical characteristics of pore water and karst water. In accord with the condition of reduction, if oxidizable organic matter exists, bacteria can reduce SO 4 2− in groundwater to H 2 S (Equation 7), causing large isotopic fractionation, bringing about the enrichment of 34 S-SO 4 and the decrease of SO 4 2− concentration (Huang et al 2023). As Fig.…”

“…Wang et al (2022) and Mao et al (2022) respectively used the self-organization mapping function of artificial intelligence to analyze isotope and hydro chemical data of the mining area, studying the changes of hydro chemical characteristics before and after mining, which revealed the mechanism of hydrogeochemical evolution in the multilayer aquifer before and after mining, as well as the sulfur cycle process of the mining area. Huang et al (2023) employed multi-isotope and hydro chemical analysis to investigate the source of sulfate and the sulfur cycling process in groundwater in North-China-type coal mines surrounding area . Previous researches have, mostly focused on the sulfur cycle of groundwater in mining areas by means of hydrochemistry and multi-isotope analysis (Ágnes et al 2022;Ren et al 2021;Zheng et al 2019), while little paid attention to the subsidence area around the mining area caused by mining.…”