Draft genome sequence data of Microbacterium sp. strain Be9 isolated from uranium-mill tailings porewaters

Microbacterium are Gram-positive, nonspore-forming, rod- shaped bacteria inhabiting a wide range of environments in- cluding soil, water, dairy products, other living organisms, etc. Microbacterium sp. strain Be9, isolated from mill tail- ings porewaters in France, shows a remarkable behavior in presence of uranium under distinct conditions, which is the main reason for the interest in sequencing its genome. In this work, we describe the draft genome sequence of Be9, comprising 4,046,806 bp, with a G + C content of 68.10% and containing 3,947 protein-coding sequences. The prelim- inary genome annotation analysis identified some genes en- coding for resistance to antibiotics and toxic compounds like heavy metals. This draft genome has been deposited at DDBJ/ENA/GenBank under the accession PRJNA590666.Orano MiningDepartamento de Microbiología Universidad de Granad

Mapping U-238 decay chain equilibrium state in thin sections of geo-materials by digital autoradiography and microprobe analysis

A new approach is proposed in order to spatially localize and determine the equilibrium state of natural decay chains on hand-scale geological samples, thanks to a combination of three techniques: 1) Elementary chemical mapping by microprobe; 2) Alpha autoradiograph by gaseous detectors and 3) bulk alpha particle spectrometry. The quantitative nature of alpha autoradiograph and its comparison with U chemical maps allows to locate radioactive equilibrium state in four samples. This equilibrium state was confirmed by alpha spectrometry analysis.Peer reviewe

Geochemical control on uranium(IV) mobility in a mining-impacted wetland

Wetlands often act as sinks for uranium and other trace elements. Our previous work at a mining-impacted wetland in France showed that a labile noncrystalline U(IV) species consisting of U(IV) bound to Al-P-Fe-Si aggregates was predominant in the soil at locations exhibiting a U-containing clay-rich layer within the top 30 cm. Additionally, in the porewater, the association of U(IV) with Fe(II) and organic matter colloids significantly increased U(IV) mobility in the wetland. In the present study, within the same wetland, we further demonstrate that the speciation of U at a location not impacted by the clay-rich layer is a different noncrystalline U(IV) species, consisting of U(IV) bound to organic matter in soil. We also show that the clay-poor location includes an abundant sulfate supply and active microbial sulfate reduction that induce substantial pyrite (FeS2) precipitation. As a result, Fe(II) concentrations in the porewater are much lower than those at clay-impacted zones. U porewater concentrations (0.02-0.26 mu M) are also considerably lower than those at the clay-impacted locations (0.21-3.4 mu M) resulting in minimal U mobility. In both cases, soil-associated U represents more than 99% of U in the wetland. We conclude that the low U mobility reported at clay-poor locations is due to the limited association of Fe(II) with organic matter colloids in porewater and/or higher stability of the noncrystalline U(IV) species in soil at those locations

Mobile uranium(IV)-bearing colloids in a mining-impacted wetland

Tetravalent uranium is commonly assumed to form insoluble species, resulting in the immobilization of uranium under reducing conditions. Here we present the first report of mobile U(IV)-bearing colloids in the environment, bringing into question this common assumption. We investigate the mobility of uranium in a mining-impacted wetland in France harbouring uranium concentrations of up to 14,000 p. p. m. As an apparent release of uranium into the stream passing through the wetland was observable, we examine soil and porewater composition as a function of depth to assess the geochemical conditions leading to this release. The analyses show the presence of U(IV) in soil as a non-crystalline species bound to amorphous Al-P-Fe-Si aggregates, and in porewater, as a distinct species associated with Fe and organic matter colloids. These results demonstrate the lability of U(IV) in these soils and its association with mobile porewater colloids that are ultimately released into surface water

Industrial Deployment of Reactive Transport Simulation: An Application to Uranium In situ Recovery

International audienc

Molecular biomarkers study of an ombrotrophic peatland impacted by an anthropogenic clay deposit

International audienceNorthern peatlands are estimated to store up to one third of all terrestrial carbon as peat and, even though a large extent of boreal peatlands is in pristine condition, extensive areas have been affected by natural or anthropogenic disturbance. Here, we aimed to study the bulk organic matter, elemental composition and molecular inventory of a peat disturbed by a clay deposit in the mesotelm layer (from −35 to −45 cm) due to mining activity near the peatland zone. We therefore investigated loss on ignition, elemental analysis, lignin monomers and non-cellulose carbohydrates, as well as the lipid fraction. In general, no significant impact on peatland evolution was noted, the only odd result being an increase in complex lipids containing acyl groups in the clay deposit zone, although this did not influence the distributions of the fatty acids, which had a bimodal distribution at C16 and C24/C26, typical of a non-impacted Sphagnum dominated peatland. Phospholipid analysis showed an increase in the quantity of mid-chain branched fatty acids, suggesting high sulfate reducing activity in the underlying clay deposit. Other lipid, lignin and carbohydrate biomarkers showed a normal peatland evolution, plant deposition being apparent in the bottom layer designated by the catotelm and microbial activity and production being highest in the upper layer, represented by the acrotelm and mesotelm

Dissolution of beidellite in acidic solutions: Ion exchange reactions and effect of crystal chemistry on smectite reactivity

International audienc

Environmental geochemistry and bioaccumulation/bioavailability of uranium in a post-mining context – The Bois-Noirs Limouzat mine (France)

International audienc