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Microbial communities in a former pilot-scale uranium mine in Eastern Finland - Association with radium immobilization.

https://arctichealth.org/en/permalink/ahliterature303109
Source
Sci Total Environ. 2019 Oct 10; 686:619-640
Publication Type
Journal Article
Date
Oct-10-2019
Author
Merja Lusa
Jenna Knuutinen
Marcus Lindgren
Juhani Virkanen
Malin Bomberg
Author Affiliation
Department of Chemistry, Radiochemistry, Faculty of Science, University of Helsinki, Finland. Electronic address: merja.lusa@helsinki.fi.
Source
Sci Total Environ. 2019 Oct 10; 686:619-640
Date
Oct-10-2019
Language
English
Publication Type
Journal Article
Keywords
Archaea
Bacteria
Finland
Fungi
Microbiota
Proteobacteria
Radium - metabolism
Soil Microbiology
Soil Pollutants, Radioactive - metabolism
Uranium
Abstract
The bacterial, fungal and archaeal communities were characterized in 17 top soil organic and mineral layer samples and in top sediment samples of the Paukkajanvaara area, a former pilot-scale uranium mine, located in Eno, Eastern Finland, using amplicon sequencing and qPCR. Soil and sediment samples were in addition analyzed for radium (226Ra), sulfate (SO42-), nitrate (NO3-) and phosphate (PO43-) concentrations. New bacterial strains, representing Pseudomonas spp., were isolated from the mine and reference area and used in laboratory experiments on uptake and leaching of radium (Ra). The effect of these strains on the sulfate leaching from the soil samples was also tested in vitro. Between 6?×?106 and 5?×?108 copies g-1 DW (dry weight) of bacterial 16S rRNA genes, 5?×?105-1?×?108 copies g-1 DW archaeal 16S rRNA genes and 1?×?105-1?×?108 copies g-1 DW fungal 5.8S rRNA genes were detected in the samples. A total of 814, 54 and 167 bacterial, archaeal and fungal genera, respectively, were identified. Proteobacteria, Euryarchaeota and Mortiriella were the dominant bacterial, archaeal and fungal phyla, respectively. All tested Pseudomonas spp. strains isolates from Paukkajanvaara removed Ra from the solution, but the amount of removed Ra depended on incubation conditions (temperature, time and nutrient broth). The highest removal of Ra (5320?L/kg DW) was observed by the Pseudomonas sp. strain T5-6-I at 37?°C. All Pseudomonas spp. strains decreased the release of Ra from soil with an average of 23% while simultaneously increasing the concentration of SO42- in the solution by 11%. As Pseudomonas spp. were frequent in both the sequence data and the cultures, these bacteria may play an important role in the immobilization of Ra in the Paukkajanvaara mine area.
PubMed ID
31185409 View in PubMed
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Sorption and speciation of selenium in boreal forest soil.

https://arctichealth.org/en/permalink/ahliterature282812
Source
J Environ Radioact. 2016 Nov;164:220-231
Publication Type
Article
Date
Nov-2016
Author
Mervi Söderlund
Juhani Virkanen
Stellan Holgersson
Jukka Lehto
Source
J Environ Radioact. 2016 Nov;164:220-231
Date
Nov-2016
Language
English
Publication Type
Article
Keywords
Adsorption
Finland
Selenic Acid
Selenious Acid
Selenium - analysis - chemistry
Soil - chemistry
Soil Pollutants - analysis - chemistry
Taiga
Abstract
Sorption and speciation of selenium in the initial chemical forms of selenite and selenate were investigated in batch experiments on humus and mineral soil samples taken from a 4-m deep boreal forest soil excavator pit on Olkiluoto Island, on the Baltic Sea coast in southwestern Finland. The HPLC-ICP-MS technique was used to monitor any possible transformations in the selenium liquid phase speciation and to determine the concentrations of selenite and selenate in the samples for calculation of the mass distribution coefficient, Kd, for both species. Both SeO3(2-) and SeO4(2-) proved to be resistant forms in the prevailing soil conditions and no changes in selenium liquid phase speciation were seen in the sorption experiments in spite of variations in the initial selenium species, incubation time or conditions, pH, temperature or microbial activity. Selenite sorption on the mineral soil increased with time in aerobic conditions whilst the opposite trend was seen for the anaerobic soil samples. Selenite retention correlated with the contents of organic matter and weakly crystalline oxides of aluminum and iron, solution pH and the specific surface area. Selenate exhibited poorer sorption on soil than selenite and on average the Kd values were 27-times lower. Mineral soil was more efficient in retaining selenite and selenate than humus, implicating the possible importance of weakly crystalline aluminum and iron oxides for the retention of oxyanions in Olkiluoto soil. Sterilization of the soil samples decreased the retention of selenite, thus implying some involvement of soil microbes in the sorption processes or a change in sample composition, but it produced no effect for selenate. There was no sorption of selenite by quartz, potassium feldspar, hornblende or muscovite. Biotite showed the best retentive properties for selenite in the model soil solution at about pH 8, followed by hematite, plagioclase and chlorite. The Kd values for these minerals were 18, 14, 8 and 7 L/kg, respectively. It is proposed that selenite sorption is affected by the structural Fe(II) in biotite, which is capable of inducing the reduction of SeO3(2-) to Se(0). Selenite probably forms a surface complex with Fe(III) atoms on the surface of hematite, thus explaining its retention on this mineral. None of the minerals retained selenate to any extent.
PubMed ID
27521902 View in PubMed
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