College of Resource and Environmental Engineering, Guizhou University, Guiyang, Guizhou, 550025, China.
Key laboratory of Karst Environment and Geohazard, Ministry of Land and Resources, Guiyang, 550025, China.
Environ Sci Pollut Res Int. 2018 Jan;25(2):1220-1230. doi: 10.1007/s11356-017-0488-y. Epub 2017 Oct 29.
Zhijin coal-mining district, located in Midwestern Guizhou Province, has been extensively exploited for several decades. The discharge of acid mine drainage (AMD) has constituted a serious threat to local water environmental quality, which greatly affected the normal use of local people. The Permian limestone aquifer is the essential potable water supply for local people, which covered under the widely distributed coal seams. To investigate the origin of the water, the evolutionary processes, and the sources of dissolved sulfate in the karst waters, the mine water, surface water, and groundwater near the coal mines were sampled for stable isotopes (H, O, and S) and conventional hydrochemical analysis. The results of hydrochemistry and isotopic composition indicate that the regional surface water and partial karst groundwater are obviously affected by coal-mining activities, which is mainly manifested in the increase of water solute concentration and the change of hydrochemical types. The isotopic composition of δH and δO indicates that the major recharge source of surface water and the groundwater is atmospheric precipitation and that it is influenced obviously by evaporation in the recharge process. The surface water is mainly controlled by the oxidation of pyrite, as well as the dissolution of carbonate rocks, whereas that of natural karst waters is influenced by the dissolution of carbonate rocks. The resulting δS values suggest that the dissolved sulfate source in the surface water is mainly pyrite oxidation but atmospheric precipitation for the karst groundwater. Given the similar chemistry and isotopic composition between surface water and partial groundwater, it is reasonable to assume that most of the dissolved sulfate source in part of the groundwater was derived through the oxidation of pyrite in the coal. Furthermore, the contamination of the surface water and partial groundwater from the coal seam has occurred distinctly in the catchment, which is enriched in SO and is mostly depleted δS in sulfate.
织金矿区位于贵州省中西部，已开采数十年。酸性矿山排水（AMD）的排放对当地水环境质量构成了严重威胁，严重影响了当地居民的正常用水。二叠系灰岩含水层是当地居民的主要饮用水源，覆盖在广泛分布的煤层之下。为了研究水的来源、演化过程以及岩溶水中溶解硫酸盐的来源，对煤矿附近的矿井水、地表水和地下水进行了稳定同位素（H、O 和 S）和常规水化学分析。水化学和同位素组成的结果表明，区域地表水和部分岩溶地下水明显受到采煤活动的影响，主要表现为水溶质浓度的增加和水化学类型的变化。δH 和 δO 的同位素组成表明，地表水和地下水的主要补给源是大气降水，在补给过程中受到蒸发的明显影响。地表水主要受黄铁矿氧化和碳酸盐岩溶解的控制，而天然岩溶水则受碳酸盐岩溶解的影响。所得的 δS 值表明，地表水的溶解硫酸盐源主要来自黄铁矿氧化，但岩溶地下水则来自大气降水。鉴于地表水和部分地下水具有相似的化学和同位素组成，可以合理地假设部分地下水的大部分溶解硫酸盐源是通过煤层中黄铁矿的氧化产生的。此外，地表水和部分地下水已经在流域中受到了明显的煤层污染，该流域中 SO 含量丰富，硫酸盐的 δS 值大部分耗尽。
