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Quantification and characterization of mercury resistant bacteria in sediments contaminated by artisanal small-scale gold mining activities, Kedougou region, Senegal

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Published in Journal of Geochemical Exploration. 2019, vol. 205, 106353
Abstract This study describes Hg-resistant bacterial present in the aquatic sediments artisanal small-scale gold mining ASGM activities along Gambia River Kedougou, Senegal. Mercury (Hg) is used for gold amalgamation in artisanal small-scale gold mining (ASGM) activities. The level of total Hg in sediment samples was determined by automatic mercury analyser. Bacterial (colony-forming units) susceptibility to Hg was evaluated by minimal inhibitory concentrations. The phylogenetic diversity analysis of the Hg-resistant bacteria was performed by PCR amplification of 16S rDNA on isolated bacterial strains, followed by restriction fragment length polymorphism, cloning and sequencing. The results documente high concentrations of Hg in ASGM activity areas, ranging between 2.4 to 6.2 mg kg-1. Population densities of heterotrophic bacteria in wet sediment ranging from 3.7x106 to 4.6x108 CFU g-1. The isolated bacterial strains from highly Hg-contaminated sites can grow to medium containing up to 17 mg L-1 of Hg2+. In this study, bacterial strains resistant to Hg are Stenotrophomonas maltophilia, Dyella ginsengisoli, Arthobacter defluvi, Arthobacter pascens, Bacillus firmus and Pseudomonas moraviensis. Our results demonstrate the occurrence the presence of diverse groups of bacterial strains resistant to metal (Hg) under tropical conditions. The isolated strains are particularly interesting for further studies to evaluate their role in bioremediation of Hg in contaminated aquatic ecosystems.
Keywords Mercury resistant bacteriaArtisanal small-scale gold miningBioremediation
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Structures
Research groups Mineral Resources and Geofluids
FORE9 Environmental microbiology
Projects Sida-UNESCO project 503RAF2000
Lombard Foundation and Schmidheiny Foundation, Geneva, Switzerland
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(ISO format)
NIANE, Birane et al. Quantification and characterization of mercury resistant bacteria in sediments contaminated by artisanal small-scale gold mining activities, Kedougou region, Senegal. In: Journal of Geochemical Exploration, 2019, vol. 205, p. 106353. doi: 10.1016/j.gexplo.2019.106353 https://archive-ouverte.unige.ch/unige:121520

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Deposited on : 2019-08-12

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