State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, PR China; Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan 430074, PR China.
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, PR China.
J Hazard Mater. 2023 Jul 15;454:131566. doi: 10.1016/j.jhazmat.2023.131566. Epub 2023 May 3.
Dissolved organic matter (DOM) play critical roles in arsenic (As) biotransformation in groundwater, but its compositional characteristics and interactions with indigenous microbial communities remain unclear. In this study, DOM signatures coupled with taxonomy and functions of microbial community were characterized in As-enriched groundwater by excitation-emission matrix, Fourier transform ion cyclotron resonance mass spectrometry and metagenomic sequencing. Results showed that As concentrations were significantly positively correlated with DOM humification (r = 0.707, p < 0.01) and the most dominant humic acid-like DOM components (r = 0.789, p < 0.01). Molecular characterization further demonstrated high DOM oxidation degree, with the prevalence of unsaturated oxygen-low aromatics, nitrogen (N/N)-containing compounds and unique CHO molecules in high As groundwater. These DOM properties were consistent with microbial composition and functional potentials. Both taxonomy and binning analyses demonstrated the dominance of Pseudomonas stutzeri, Microbacterium and Sphingobium xenophagum in As-enriched groundwater which possessed abundant As-reducing gene, with organic carbon degrading genes capable of labile to recalcitrant compounds degradation and high potentials of organic nitrogen mineralization to generate ammonium. Besides, most assembled bins in high As groundwater presented strong fermentation potentials which could facilitate carbon utilization by heterotrophic microbes. This study provides better insight into the potential role of DOM mineralization for As release in groundwater system.
溶解有机质（DOM）在地下水砷的生物转化中起着关键作用，但 DOM 的组成特征及其与土著微生物群落的相互作用仍不清楚。本研究通过激发发射矩阵、傅里叶变换离子回旋共振质谱和宏基因组测序，研究了富砷地下水中 DOM 特征与其微生物群落的分类和功能之间的关系。结果表明，砷浓度与 DOM 的腐殖化程度（r = 0.707，p < 0.01）和最主要的类腐殖酸 DOM 成分（r = 0.789，p < 0.01）呈显著正相关。分子特征进一步表明，DOM 具有较高的氧化程度，富含不饱和含氧-低芳香族、含氮（N/N）化合物和独特的 CHO 分子。这些 DOM 特性与微生物组成和功能潜力一致。分类和分箱分析都表明，假单胞菌、微杆菌和噬硫菌在富砷地下水中占优势，这些菌具有丰富的砷还原基因，具有将易降解有机碳转化为难降解有机碳的能力，并具有将有机氮矿化为铵的高潜力。此外，高砷地下水中的大多数组装箱都表现出较强的发酵潜力，这有利于异养微生物利用碳。本研究深入了解了 DOM 矿化对地下水中砷释放的潜在作用。
