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

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 (Ra-226), radium 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 x 10(6) and 5 x 10(8) copies g(-1) DW (dry weight) of bacterial 16S rRNA genes, 5 x 10(5)-1 x 10(8) copies g(-1) DW archaeal 16S rRNA genes and 1 x 10(5)-1 x 10(8) 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 degrees 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. (C) 2019 The Authors. Published by Elsevier B.V.Peer reviewe

Anion exchange on hydrous zirconium oxide materials: application for selective iodate removal

The radioactive 129I is a top-priority radionuclide due to its the long half-life (1.57 × 107 years) and high mobility. Because of the planned and accidental releases to the environment, specific separation technologies are required to limit the potential radiation dose to human beings. Zirconium oxides are known for their adsorption capability and selectivity to oxyanions and here the applicability to selective IO3− removal has been investigated regarding the uptake mechanism, regeneration and competition caused by other anions, like environmentally relevant SO42−. Granular aggregates of hydrous zirconium oxides with and without Sb doping showed high potential for the selective IO3− removal in the presence of competing anions, like the forementioned SO42− (apparent capacity between 0.1–0.4 meq g−1 depending on SO42− concentration). The main uptake mechanism was found to be outer-sphere complexation (ion-exchange) to the protonated hydroxyl groups of hydrous zirconium oxides, but also minor mechanisms were identified including inner-sphere complexation and reduction to I−. The materials were observed to be easily and successively regenerated using dilute acid. Hydrous zirconium oxides showed high potential for IO3− removal from waste solutions regarding technical (high selectivity and apparent capacity) and ecological/economic (feasible regeneration) aspects.The radioactive I-129 is a top-priority radionuclide due to its the long half-life (1.57 x 10(7) years) and high mobility. Because of the planned and accidental releases to the environment, specific separation technologies are required to limit the potential radiation dose to human beings. Zirconium oxides are known for their adsorption capability and selectivity to oxyanions and here the applicability to selective IO3- removal has been investigated regarding the uptake mechanism, regeneration and competition caused by other anions, like environmentally relevant SO42-. Granular aggregates of hydrous zirconium oxides with and without Sb doping showed high potential for the selective IO3- removal in the presence of competing anions, like the forementioned SO42- (apparent capacity between 0.1-0.4 meq g(-1) depending on SO42- concentration). The main uptake mechanism was found to be outer-sphere complexation (ion-exchange) to the protonated hydroxyl groups of hydrous zirconium oxides, but also minor mechanisms were identified including inner-sphere complexation and reduction to I-. The materials were observed to be easily and successively regenerated using dilute acid. Hydrous zirconium oxides showed high potential for IO3- removal from waste solutions regarding technical (high selectivity and apparent capacity) and ecological/economic (feasible regeneration) aspects.Peer reviewe

Release of base and potentially harmful metals from waste deposits at a former uranium mine in eastern Finland

Peer reviewe

Metal concentrations of sediments in Vanhankaupunginlahti dam basin, river Vantaa

Non peer reviewe

Release of radionuclides from waste rock and tailings at a former pilot uranium mine in eastern Finland

The Paukkajanvaara mine in Eno, eastern Finland, started to operate in 1959. The mine was a test site for assessing the feasibility of larger-scale uranium extraction. Pilot-scale mining and milling were carried out between 1958 and 1961, and the mine site was rehabilitated in the early 1990s. The aim of this study was to examine the potential for further mobilization of radionuclides after remediation. There are two primary sources of contamination at the site, the waste-rock pile and the tailings. Our study indicates that 226Ra leached from the waste-rock pile and accumulated in surrounding soil. In run-off sediment samples collected from a dry stream bed near the waste-rock pile, the activity concentrations of 226Ra and 238U were higher than in soil samples. From the tailings, radionuclides can leach directly to the lake and to another small stream, which flows to the east of the waste-rock pile. In the water samples collected from this stream, uranium concentrations increased at the outlet to the lake. The results from the soil samples collected between the tailings area and the stream indicate leaching of 238U and 226Ra with the surface flow. Sediment samples collected from the bottom of the lake displayed pronounced uranium series disequilibrium with fractionations of 210Pb and 226Ra relative to the parent 238U. The results therefore indicate that leaching and accumulation of at least 226Ra from the waste-rock pile and possibly tailings is still ongoing.Peer reviewe

Hemin and Cobalt Protoporphyrin Inhibit NLRP3 Inflammasome Activation by Enhancing Autophagy : A Novel Mechanism of Inflammasome Regulation

Inflammasomes are intracellular protein platforms, which, upon activation, produce the highly proinflammatory cytokines interleukin (IL)-1 beta and IL-18. Heme, hemin and their degradation products possess significant immunomodulatory functions. Here, we studied whether hemin regulates inflammasome function in macrophages. Both hemin and its derivative, cobalt protoporphyrin (CoPP), significantly reduced IL-1 beta secretion by cultured human primary macrophages, the human monocytic leukemia cell line and also mouse bone marrow-derived and peritoneal macrophages. Intraperitoneal administration of CoPP to mice prior to urate crystal-induced peritonitis alleviated IL-1 beta secretion to the peritoneal cavity. In cultured macrophages, hemin and CoPP inhibited NLRP3 inflammasome assembly by reducing the amount of intracellular apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC). The reduction of ASC was associated with enhanced autophagosome formation and autophagic flux. Inhibition of autophagy prevented the CoPP-induced depletion of ASC, implying that the depletion was caused by increased autophagy. Our data indicate that hemin functions as an endogenous negative regulator of the NLRP3 inflammasome. The inhibition is mediated via enhanced autophagy that results in increased degradation of ASC. This regulatory mechanism may provide a novel approach for the treatment of inflammasome-related diseases. (C) 2016 S. Karger AG, BaselPeer reviewe

Direct field evidence of autocatalytic iodine release from atmospheric aerosol

Reactive iodine plays a key role in determining the oxidation capacity, or cleansing capacity, of the atmosphere in addition to being implicated in the formation of new particles in the marine boundary layer. The postulation that heterogeneous cycling of reactive iodine on aerosols may significantly influence the lifetime of ozone in the troposphere not only remains poorly understood but also heretofore has never been observed or quantified in the field. Here, we report direct ambient observations of hypoiodous acid (HOI) and heterogeneous recycling of interhalogen product species (i.e., iodine monochloride [ICI] and iodine monobromide [IBr]) in a midlatitude coastal environment. Significant levels of ICI and IBr with mean daily maxima of 4.3 and 3.0 parts per trillion by volume (1-min average), respectively, have been observed throughout the campaign. We show that the heterogeneous reaction of HOI on marine aerosol and subsequent production of iodine interhalogens are much faster than previously thought. These results indicate that the fast formation of iodine interhalogens, together with their rapid photolysis, results in more efficient recycling of atomic iodine than currently considered in models. Photolysis of the observed ICI and IBr leads to a 32% increase in the daytime average of atomic iodine production rate, thereby enhancing the average daytime iodine-catalyzed ozone loss rate by 10 to 20%. Our findings provide direct field evidence that the autocatalytic mechanism of iodine release from marine aerosol is important in the atmosphere and can have significant impacts on atmospheric oxidation capacity.Peer reviewe

Ethanol Inhibits Activation of NLRP3 and AIM2 Inflammasomes in Human Macrophages- A Novel Anti-Inflammatory Action of Alcohol

Peer reviewe