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Radioactive 129I with a long half-life (1.57 × 107 y) and high mobility is a serious radiohazard and one of the top risk radionuclides associated with its accidental and planned releases to nature. The complex speciation chemistry of iodine makes its removal a complicated task, and usually a single method is not able to remove all iodine species. Especially its oxidized form iodate (IO3−) lacks a selective and effective removal method. Here, the granular aggregates of hydrous zirconium oxides with and without antimony doping were tested for IO3− removal and the effects of contact time, competing anions in different concentrations and pH were examined. The materials showed high selectivity for IO3− (Kd over up to 50,000 ml/g) in the presence of competing ions and relatively fast uptake kinetics (eq. < 1 h). However, B(OH)4− and SO42−, as competing ions, lowered the iodate uptake significantly in basic and acidic solution, respectively. The suitability of the materials for practical applications was tested in a series of column experiments where the materials showed remarkably high apparent capacity for the IO3− uptake (3.2–3.5 mmol/g). [ABSTRACT FROM AUTHOR]

1 The effects of catchment fire on lake Pieni Majaslampi are examined by means of geochemical, charcoal, pollen, and diatom analyses of surface sediments. Particular emphasis is paid to pH responses in this naturally acid, weakly buffered, small-catchment lake. 2 An increase of c. 0.9 units in diatom-inferred pH correlates with dendro-chronological evidence of catchment fire around 1890. This pH rise may have been caused by increased turbulent mixing of the water column, as well as increased inputs of elastic erosional material and atmospheric ash, rich in base cations, after the fire. 3 Inferred pH remained high until the 1930s, after which there is a slow recovery of the system at a rate [approximately equal to] 0.2 pH units per decade. 4 The inferred pH stabilizes to a level slightly higher than the prefire value by the 1960s. High concentrations of S and Fe and elevated Fe/Mn ratios in the upper sediment layer reflect increased in-situ alkalinity generation following fire. 5 The processes controlling the acidity dynamics in small-catchment lakes may be more complex than has hitherto been thought. Keywords: diatoms, disturbance, Finland, fire, geochemistry, in-lake alkalinity, lake acidity, palaeolimnology

A sediment core from Lake Kuttanen, a small closed lake in Finnish Lapland, was investigated to determine the effects of Holocene water-table changes, aeolian activity and forest fires on sediment physical properties and sediment geochemistry. Sediment properties were examined by water content, loss-on-ignition (LOI) and dry matter sedimentation rate analyses. Sediment geochemistry was studied by determining the acid-soluble accumulation rates of Al, Ca, Cu, Fe, K, Mg, Mn, Na, P and Zn. The Fe/Mn ratio was calculated to study changes in the redox potential and charcoal concentrations were measured to determine the occurrence of local and regional fires. The sediment accumulation rate was determined using 14 C and b-activity measurements. Principal components analysis (PCA) was used to examine variations within the data and intercorrelations among the variables. After the isolation of the basin, all the element accumulation values were high because of the erosional supply from the catchment before stable soil formation. During the supposed termination of the early Holocene dry and warm period (6000–4000 cal. BP) the element and dry matter accumulation values decreased and LOI increased rapidly. The sedimentation rate increased gradually and the element accumulation values began to increase after 4000 cal. BP along with the increase in dry matter accumulation. The accumulation of Fe was affected also by chemical mobilization from the soils. The LOI values decrease gradually towards the sediment surface, suggesting higher water levels, increasing aeolian activity on a regional scale and dilution by Fe supply from the catchment soils. About 900 cal. BP this activity began locally very near the lake. Charcoal analysis shows that forest fires were a common feature on a regional scale. Their geochemical impact is somewhat unclear; perhaps because most were of little or no geochemical significance, which may have been related to the properties of the permeable soil of the catchment. The fires around 1600 and 900 cal. BP probably triggered the aeolian activity near the lake, which has led to the mobilization of Fe from the catchment, and reverse datings in the 14 C analysis. Thus, natural environmental changes can cause rapid sedimentological and geochemical changes. The main force behind the changes appears to be climatic. [ABSTRACT FROM AUTHOR]

Paleolimnological methods are combined with statistical multivariateanalyses (PCA and CCA) to study the effects of local environmental disturbances and changes in loading of atmospheric origin on water acidity and the physiochemical properties of the sediment in a small, naturally acidic rocky lake in southern Finland. The pH of the lake as calculated from the diatom flora increased by 0.9 pH units as a consequence of a forest fire in the catchment area at the turn of the lastcentury, and the changes in the diatom assemblages point to an increase in dys(eu)trophy and turbulence. In terms of element influx (in mu g cm{sup}-2{end} yr{sup}-1{end}), the effects of the fire are seen in a slight increase in the accumulation of lithophilous elements. Diatom-inferred pH values decline upwards in the sediment, but do not regain the level recorded before the fire. This is attributed to reactions between Fe{sup}3+{end} and S, which has partly accumulated from the air as SO{sub}4{end}{sup}2-{end}, producing internal alkalinity. Accumulation rates of many elements increase markedly after the 1960s, an effect for Al, Mg, Na, P and Zn may be connected mainly with theenhanced accumulation of dry matter, whereas the accumulation of K, Ni, Pb, Ti and V in surface sediment are obviously related to atmospheric loading. Measured accumulation rates of Cd and Cu are lower thanthe calculated values especially in the surface sediment, possibly because of diagenetic changes. Accumulation of Ca and Mn decreases towards the surface on account of acidification of anthropogenic origin. [ABSTRACT FROM AUTHOR]

The radioactive 129 I is a top-priority radionuclide due to its the long half-life (1.57 × 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 IO 3 - removal has been investigated regarding the uptake mechanism, regeneration and competition caused by other anions, like environmentally relevant SO 4 2- . Granular aggregates of hydrous zirconium oxides with and without Sb doping showed high potential for the selective IO 3 - removal in the presence of competing anions, like the forementioned SO 4 2- (apparent capacity between 0.1-0.4 meq g -1 depending on SO 4 2- 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 IO 3 - removal from waste solutions regarding technical (high selectivity and apparent capacity) and ecological/economic (feasible regeneration) aspects., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

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 [ICl] and iodine monobromide [IBr]) in a midlatitude coastal environment. Significant levels of ICl 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 ICl 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., Competing Interests: The authors declare no competing interest., (Copyright © 2021 the Author(s). Published by PNAS.)

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 ( 226 Ra), sulfate (SO 4 2- ), nitrate (NO 3 - ) and phosphate (PO 4 3- ) 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 × 10 6 and 5 × 10 8 copies g -1 DW (dry weight) of bacterial 16S rRNA genes, 5 × 10 5 -1 × 10 8 copies g -1 DW archaeal 16S rRNA genes and 1 × 10 5 -1 × 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 °C. All Pseudomonas spp. strains decreased the release of Ra from soil with an average of 23% while simultaneously increasing the concentration of SO 4 2- 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., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Inflammasomes are intracellular protein platforms, which, upon activation, produce the highly proinflammatory cytokines interleukin (IL)-1β 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-1β 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-1β 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., (© 2016 S. Karger AG, Basel.)

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, K d , for both species. Both SeO 3 2- and SeO 4 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 K d 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 K d 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 SeO 3 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., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Extracellular ATP is an endogenous danger signal that is known to activate inflammatory responses in innate immune cells, including macrophages. Activated macrophages start to secrete proteins to induce an immune response, as well as to recruit other immune cells to the site of infection and tissue damage. In this study, we characterized the secretome (i.e., the global pattern of secreted proteins) of ATP-stimulated human macrophages. We show that ATP stimulation activates robust vesicle-mediated unconventional protein secretion, including exosome release and membrane shedding, from human macrophages. Pathway analysis of the identified secreted proteins showed that calpain-related pathways were overrepresented in the secretome of ATP-stimulated cells. In accordance with this, calpains, which are calcium-dependent nonlysosomal cysteine proteases, were activated upon ATP stimulation through a P2X purinoceptor 7 receptor-dependent pathway. Functional studies demonstrated that calpain activity is essential for the P2X purinoceptor 7 receptor-mediated activation of unconventional protein secretion. Unconventional protein secretion was followed by cell necrosis and NLRP3 inflammasome-mediated secretion of the mature form of the proinflammatory cytokine IL-1β. Furthermore, ATP-driven NLRP3 inflammasome activation was also dependent on calpain activity. Interestingly, pro-IL-1β and inflammasome components ASC and caspase-1 were released by ATP-activated macrophages through a vesicle-mediated secretion pathway. In conclusion, to our knowledge, we provide the first global characterization of proteins secreted by ATP-activated human macrophages and show a pivotal role for calpains in the activation of the inflammatory response during ATP exposure., (Copyright © 2016 by The American Association of Immunologists, Inc.)

Objective: In the pathogenesis of coronary atherosclerosis, local macrophage-driven inflammation and secretion of proinflammatory cytokines, interleukin-1β (IL-1β) in particular, are recognized as key factors. Moderate alcohol consumption is associated with a reduced risk of coronary artery disease mortality. Here we examined in cultured human macrophages whether ethanol modulates the intracellular processes involved in the secretion of IL-1β., Results: Ethanol decreased dose-dependently the production of mature IL-1β induced by activators of the NLRP3 inflammasome, i.e. ATP, cholesterol crystals, serum amyloid A and nigericin. Ethanol had no significant effect on the expression of NLRP3 or IL1B mRNA in LPS-primed macrophages. Moreover, secretion of IL-1β was decreased in parallel with reduction of caspase-1 activation, demonstrating that ethanol inhibits inflammasome activation instead of synthesis of pro-IL-1β. Acetaldehyde, a highly reactive metabolite of ethanol, had no effect on the ATP-induced IL-1β secretion. Ethanol also attenuated the secretion of IL-1β triggered by synthetic double-stranded DNA, an activator of the AIM2 inflammasome. Ethanol conferred the inhibitory functions by attenuating the disruption of lysosomal integrity and ensuing leakage of the lysosomal protease cathepsin B and by reducing oligomerization of ASC., Conclusion: Ethanol-induced inhibition of the NLRP3 inflammasome activation in macrophages may represent a biological pathway underlying the protective effect of moderate alcohol consumption on coronary heart disease.