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Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron OxyHydroxides, Trace Elements, and Bacteria
Published on: December 19, 2017
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Arsenic behavior in river sediments under redox gradient: a review.
Josselin Gorny1, Gabriel Billon1, Ludovic Lesven1
1Laboratory Geosystèmes, UMR 8217 CNRS - University Lille 1, Villeneuve d'Ascq, France.
The Science of the Total Environment
|December 3, 2014
Summary
Arsenic speciation in sediments is governed by microbial redox processes and early diagenesis. Bacterial activity drives arsenic transformations, influencing its fate and potential detoxification in aquatic environments.
Area of Science:
- Environmental Chemistry
- Geochemistry
- Microbiology
Background:
- Arsenic (As) is a redox-sensitive metalloid whose environmental fate is critical.
- Early diagenetic processes in sediments significantly influence arsenic speciation.
- Understanding arsenic transformations is key to assessing its environmental impact.
Purpose of the Study:
- To review redox mechanisms and final products of arsenic in surface sediments.
- To elucidate the role of microbial activity in arsenic transformations.
- To highlight abiotic reactions influencing arsenic speciation.
Main Methods:
- Review of existing literature on arsenic biogeochemistry in sediments.
- Analysis of redox mechanisms involving organic matter oxidation and oxidant reduction.
- Examination of abiotic reactions such as complexation, sorption, and precipitation.
Main Results:
- Bacterial activity drives redox transformations between arsenic(V) and arsenic(III) and produces methylated arsenic species.
- Abiotic redox reactions involving manganese (hydr)-oxides and reduced sulfur species are crucial.
- Sorption to iron (hydr)-oxides and binding to organic matter control arsenic fate in sediments.
Conclusions:
- Early diagenesis and microbial activity are primary drivers of arsenic speciation in sediments.
- Both biotic and abiotic reactions contribute to arsenic transformations and potential detoxification.
- Further research is needed to fully understand the role of reduced sulfur species in arsenic cycling.
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