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Li Y, Guo H, Zhao B, Gao Z, Yu C, Zhang C, Wu X. High biodegradability of microbially-derived dissolved organic matter facilitates arsenic enrichment in groundwater: Evidence from molecular compositions and structures. J Hazard Mater 2024; 470:134133. [PMID: 38574655 DOI: 10.1016/j.jhazmat.2024.134133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/16/2024] [Accepted: 03/24/2024] [Indexed: 04/06/2024]
Abstract
Although biodegradation of organic matter is well-known to trigger enrichment of arsenic (As) in groundwater, the effects of DOM sources and biodegradability on As enrichment remain elusive. In this study, groundwater samples were collected from the Hetao basin to identify DOM source and evaluate biodegradability by using spectral and molecular techniques. Results showed that in the alluvial fan, DOM was mainly sourced from terrestrially derived OM, while DOM in the flat plain was more originated from microbially derived OM. Compared to terrestrially derived DOMs, microbially derived DOMs in groundwater, which had relatively higher H/Cwa ratios, NOSC values and more biodegradable molecules, exhibited higher biodegradability. In the flat plain, microbially derived DOMs with higher biodegradability encountered stronger biodegradation, facilitating the reductive dissolution of Fe(III)/Mn oxides and As enrichment in groundwater. Moreover, the enrichment of As depended on the biodegradable molecules that was preferentially utilized for primary biodegradation. Our study highlights that the enrichment of dissolved As in the aquifers was closely associated with microbially derived DOM with high biodegradability and high ability for primary biodegradation.
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Affiliation(s)
- Yao Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Huaming Guo
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China.
| | - Bo Zhao
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Zhipeng Gao
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Chen Yu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Chaoran Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Xiong Wu
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
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