Wang Yanhong, Zhang Guanglong, Wang Helin, Cheng Yu, Liu Han, Jiang Zhou, Li Ping, Wang Yanxin
State Key Laboratory of Biogeology and Environmental Geology, 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. 2021 Jun 5;411:125146. doi: 10.1016/j.jhazmat.2021.125146. Epub 2021 Jan 14.
Dissolved organic matter (DOM) play key roles in the biotransformation of arsenic in groundwater systems. However, the effects of different types of DOM on arsenic biogeochemistry remain poorly understood. In this study, four typical DOM compounds (acetate, lactate, AQS and humic acid) were amended to high As aquifer sediments to investigate their effects on arsenic/iron biotransformation and microbial community response. Results demonstrated that different DOM drove different microbial community shifts and then enhanced microbially-mediated arsenic release and iron reduction. With labile DOM (acetate and lactate) amendment, the abundance of putative dissimilatory iron and sulfate reducers Desulfomicrobium and Clostridium sensu stricto increased within the first week, and subsequently the anaerobic fermentative bacterial genus Acetobacterium and arsenate/sulfate-reducing bacterial genus Fusibacter became predominant. In contrast, recalcitrant DOM (AQS and humic acid) mainly stimulated the abundances of sulfur compounds respiratory genus Desulfomicrobium and fermentative bacterial genus Alkalibacter in the whole incubation. Accompanied with the microbial community structure and function shifts, dissolved organic carbon concentration and oxidation-reduction potential changed and the arsenic/iron reduction increased, which resulted in the enhanced arsenic mobilization. Collectively, the present study linked DOM type to microbial community structure and explored the potential roles of different DOM on arsenic biotransformation in aquifers.
溶解有机物（DOM）在地下水系统中砷的生物转化过程中起着关键作用。然而，不同类型的DOM对砷生物地球化学的影响仍知之甚少。在本研究中，将四种典型的DOM化合物（乙酸盐、乳酸盐、蒽醌-2,6-二磺酸钠（AQS）和腐殖酸）添加到高砷含水层沉积物中，以研究它们对砷/铁生物转化和微生物群落响应的影响。结果表明，不同的DOM驱动了不同的微生物群落变化，进而增强了微生物介导的砷释放和铁还原。添加易降解的DOM（乙酸盐和乳酸盐）后，假定的异化铁还原菌和硫酸盐还原菌脱硫微菌属和严格梭菌属的丰度在第一周内增加，随后厌氧发酵细菌属醋杆菌属和砷酸盐/硫酸盐还原细菌属梭杆菌属成为优势菌属。相比之下，难降解的DOM（AQS和腐殖酸）在整个培养过程中主要刺激了硫化合物呼吸菌属脱硫微菌属和发酵细菌属碱杆菌属的丰度。伴随着微生物群落结构和功能的变化，溶解有机碳浓度和氧化还原电位发生改变，砷/铁还原增加，导致砷的迁移增强。总体而言，本研究将DOM类型与微生物群落结构联系起来，探讨了不同DOM在含水层中砷生物转化中的潜在作用。
