Organic Carbon transport model of abandoned river channels - A motif for floodplain geomorphology influencing biogeochemical swaying of arsenic

Ghosh, D and Kumar, S and Donselaar, ME and Corroto, C and Ghosh, AK (2021) Organic Carbon transport model of abandoned river channels - A motif for floodplain geomorphology influencing biogeochemical swaying of arsenic. In: Science of the Total Environment, 762 .

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Abstract

Meandering-river geomorphology, forming abandoned channels/lakes with organic carbon-burial and microbial reductive dissolution, play many crucial roles in controlling arsenic (As) fluxes in sinks such as contaminated aquifers of riverine alluvial plains across the world. Suhiya oxbow-lake in the middle alluvial plain of the River Ganga, was selected as the natural laboratory. A top-down multidisciplinary approach was chosen employing satellite imagery to analyse the annual oxbow-lake surface vegetation dynamics (Eichhornia and Hydrilla). Side-scan sonar profiles across two oxbow lakes along with River Ganga core data and vintage topographical maps, estimated the lake-sedimentation rate of 9.6 cm/yr. Organic carbon amino acids, aromatics, lingo-phenols and lipids hydrocarbons infiltration-based on hydrophobicity and molecular-mass was detected at different depths along the water and sedimentary column. Elemental analysis showed lake surface to groundwater the As conc. varied from (0.37 to 185 μg/l). A microbial diversity based study showed that large sized photoautotrophs Nostoc, Anabaena are replaced by Fe-oxido-reducing As-metabolizing bacteria e.g. Acidovorax, Dechloromonas and enteric organisms e.g. Enterobacter, Salmonella at bottom of water column. Based on these inferences, a conceptual organic carbon transport model was constructed to understand the preferential preservation and microbial diagenesis resulting in mobilization of As and other geogenic elements. © 2020 Elsevier B.V.

Item Type:	Journal Article
Publication:	Science of the Total Environment
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to Author
Keywords:	Aquifers; Aromatic hydrocarbons; Arsenic; Geomorphology; Groundwater pollution; Groundwater resources; Hydrogeology; Lakes; Landforms; Rivers; Satellite imagery; Sedimentology, Contaminated aquifer; Floodplain geomorphologies; Microbial diversity; Multi-disciplinary approach; Natural laboratories; Organic carbon burial; Reductive dissolution; Sedimentation rates, Organic carbon, Acidovorax; Anabaena; Dechloromonas; Eichhornia; Enterobacter; Nostoc; Salmonella
Department/Centre:	Division of Mechanical Sciences > Centre for Earth Sciences
Date Deposited:	30 Dec 2021 04:39
Last Modified:	30 Dec 2021 04:39
URI:	http://eprints.iisc.ac.in/id/eprint/67672

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