Li Linwei, Cao Xingxing, Wu Pan, Bu Chujie, Ren Yeye, Li Kai
College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China.
College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China.
Sci Total Environ. 2023 Nov 1;897:165434. doi: 10.1016/j.scitotenv.2023.165434. Epub 2023 Jul 9.
Dissolved organic matter (DOM) is widely present in surface water environments and plays a critical role in the biogeochemical cycling of metal ions. Metal ions in acid mine drainage (AMD) have seriously polluted karst surface water environments, but few studies have explored interactions between DOM and metal ions in AMD-disturbed karst rivers. Here, the composition and sources of DOM in AMD-disturbed karst rivers were investigated by fluorescence excitation-emission spectroscopy combined with parallel factor analysis. In addition, correlations between metal ions and other factors (DOM components, total dissolved carbon (TDC) and pH) were determined using structural equation modeling (SEM). Results showed that there were evident differences in the seasonal distribution of TDC and metal ion concentrations in AMD-disturbed karst rivers. The concentrations of DOC, dissolved inorganic carbon (DIC), and metal ions were generally higher in the dry season than in the wet season, with Fe and Mn pollution being the most pronounced. The DOM in AMD contained two types of protein-like substances that were mainly from autochthonous inputs, while DOM in AMD-disturbed karst rivers contained two additional types of humic-like substances from both autochthonous and allochthonous inputs. The SEM results showed that the influence of DOM components on the distribution of metal ions was greater than that of TDC and pH. Among the DOM components, the influence of humic-like substances was greater than that of protein-like substances. Additionally, DOM and TDC had direct positive effects on metal ions, while pH had a direct negative effect on these. These results further elucidated the geochemical interactions between DOM and metal ions in AMD-disturbed karst rivers, which will assist in the pollution prevention of metal ions in AMD.
溶解有机物（DOM）广泛存在于地表水环境中，在金属离子的生物地球化学循环中起着关键作用。酸性矿山排水（AMD）中的金属离子严重污染了岩溶地表水环境，但很少有研究探讨受AMD干扰的岩溶河流中DOM与金属离子之间的相互作用。在此，采用荧光激发-发射光谱结合平行因子分析方法，研究了受AMD干扰的岩溶河流中DOM的组成和来源。此外，利用结构方程模型（SEM）确定了金属离子与其他因素（DOM组分、总溶解碳（TDC）和pH值）之间的相关性。结果表明，受AMD干扰的岩溶河流中TDC和金属离子浓度的季节分布存在明显差异。旱季DOC、溶解无机碳（DIC）和金属离子的浓度普遍高于雨季，其中铁和锰的污染最为明显。AMD中的DOM包含两种主要来自本地输入的类蛋白质物质，而受AMD干扰的岩溶河流中的DOM还包含另外两种来自本地和异地输入的类腐殖质物质。SEM结果表明，DOM组分对金属离子分布的影响大于TDC和pH值。在DOM组分中，类腐殖质物质的影响大于类蛋白质物质。此外，DOM和TDC对金属离子有直接的正向影响，而pH值对它们有直接的负向影响。这些结果进一步阐明了受AMD干扰的岩溶河流中DOM与金属离子之间的地球化学相互作用，这将有助于预防AMD中金属离子的污染。
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