Abstract：
Groundwater contamination by nitrate and sulfate in mining areas is a significant challenge. Consequently, the inputs sources of these contaminants and their evolution have received considerable attention, with the knowledge gained critical for improved management of water quality. This study integrated data on multiple stable isotopes and water chemistry data and a Bayesian isotope mixing model to investigate the relative contributions of inputs sources of sulfate and nitrate sources to bodies of water in a karst mining area in southwest China. The outcomes indicated that hydrochemical component in the water bodies of the study area is mainly derived from the dissolution of silicate rocks, carbonate rocks and sulfate minerals as well as the oxidation of sulfides. The human and agricultural wastewater, soil nitrogen, and fertilizers were the predominant inputs sources of nitrate to the mine water environment; the predominant inputs sources of sulfide were mineral oxidation, evaporite dissolution, atmospheric deposition, and sewage. Groundwater is mainly recharged from atmospheric precipitation, and surface water is closely hydraulically connected to groundwater. Nitrogen and oxygen isotope composition and water chemistry indicative of nitrification dominate the nitrogen cycle in the study area. The oxidation of pyrite and bacterial sulfate reduction (SRB) had no significant impact on the stable isotopes of groundwater. The results of this study demonstrate the inputs of different sources to nitrate and sulfate in karst mines and associated transformation processes. The results of this study can assist in the conservation of groundwater quality in mining areas and can act as a reference for future related studies.
摘要：
矿区硝酸盐和硫酸盐对地下水的污染是一项重大挑战。因此,这些污染物的输入源及其演变受到了相当大的关注，获得的知识对改善水质管理至关重要。本研究整合了多种稳定同位素和水化学数据的数据以及贝叶斯同位素混合模型，以研究中国西南岩溶矿区硫酸盐和硝酸盐输入源对水体的相对贡献。结果表明，研究区水体中的水化学组分主要来源于硅酸盐岩石的溶解，碳酸盐岩和硫酸盐矿物以及硫化物的氧化。人类和农业废水，土壤氮素,和肥料是硝酸盐对矿井水环境的主要输入源；硫化物的主要输入源是矿物氧化，蒸发岩溶解，大气沉降,和污水。地下水主要来自大气降水，地表水与地下水水力紧密相连。氮和氧同位素组成以及指示硝化的水化学在研究区的氮循环中占主导地位。黄铁矿的氧化和细菌硫酸盐还原(SRB)对地下水的稳定同位素没有显著影响。这项研究的结果表明了岩溶矿山中硝酸盐和硫酸盐的不同来源的输入以及相关的转化过程。本研究结果可辅助矿区地下水水质的保护，为今后相关研究提供参考。
