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Ralf Kautenburger, Jonas M Sander, Christina Hein
For the safe long-term storage of high level radioactive waste (HLW), detailed information about geo-chemical behavior of radioactive and toxic metal ions under environmental conditions is important. Natural organic matter (NOM) can play a crucial role in the immobilization or mobilization of these metal ions due to its complexation and colloid formation tendency. In this study, the complexation of europium (as chemical homologue of trivalent actinides like americium) and uranium (as main component of HLW) by ten humic acids (HA) from different sources and Suwannee NOM river extract has been analyzed...
December 6, 2016: Electrophoresis
A W Nelson, E S Eitrheim, A W Knight, D May, M D Wichman, T Z Forbes, M K Schultz
Coal is an integral part of global energy production; however, coal mining is associated with numerous environmental health impacts. It is well documented that coal-mine waste can contaminate the environment with naturally-occurring radionuclides from the uranium-238 ((238)U) decay series. However, the behavior of the final radionuclide in the (238)U-series, i.e., polonium-210 ((210)Po) arising from coal-mine waste-water discharge is largely unexplored. Here, results of a year-long (2014-2015) field study, in which the concentrations of (210)Po in sediments and surface water of a lake that receives coal-mine waste-water discharge in West Virginia are presented...
November 30, 2016: Journal of Environmental Radioactivity
D Srinivas, V Ramesh Babu, I Patra, Shailesh Tripathi, M S Ramayya, A K Chaturvedi
The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas...
November 30, 2016: Journal of Environmental Radioactivity
Michael P Thorgersen, W Andrew Lancaster, Lara Rajeev, Xiaoxuan Ge, Brian J Vaccaro, Farris L Poole, Adam P Arkin, Aindrila Mukhopadhyay, Michael W W Adams
: Cells suspensions of Pelosinus sp. strain UFO1 were previously shown, using spectroscopic analysis, to sequester uranium as U(IV) complexed with carboxyl and phosphoryl ligands on protein(s). The goal of this project was to characterize the proteins involved in uranium binding. Virtually all of the uranium in UFO1 cells was associated with a heterodimeric protein, which was termed the uranium-binding complex (UBC). UBC was composed of two S-layer domain proteins encoded by UFO1_4202 and UFO1_4203...
December 2, 2016: Applied and Environmental Microbiology
Sophie Grivès, Guillaume Phan, Céline Bouvier-Capely, David Suhard, François Rebière, Michelle Agarande, Elias Fattal
No emergency decontamination treatment is currently available in the case of radiological skin contamination by uranium compounds. First responders in the workplace or during an industrial nuclear accident must be able to treat internal contamination through skin. For this purpose, a calixarene nanoemulsion was developed for the treatment of intact skin or superficial wounds contaminated by uranium, and the decontamination efficiency of this nanoemulsion was investigated in vitro and ex vivo. The present work addresses the in vivo decontamination efficiency of this nanoemulsion, using a rat model...
November 29, 2016: Chemico-biological Interactions
Tieshan Wang, Xinyan Zheng, Xiaoyu Wang, Xia Lu, Yanghao Shen
Uranium adsorption mechanisms of live and heat-killed Saccharomyces cerevisiae in different pH values and biomass concentrations were studied under environmentally relevant conditions. Compared with live cells, the adsorption capacity of heat-killed cells is almost one order of magnitude higher in low biomass concentration and highly acidic pH conditions. To explore the mesoscopic surface interactions between uranium and cells, the characteristic of uranium deposition was investigated by SEM-EDX, XPS and FTIR...
November 29, 2016: Journal of Environmental Radioactivity
Lili Chen, Shaojie Feng, Donglin Zhao, Shaohua Chen, Feifei Li, Changlun Chen
In this work, zero-valent iron-polyaniline-graphene aerogel composite (Fe-PANI-GA) was prepared and applied in the removal of U(VI) from aqueous solutions by batch sorption experiments. The experimental results showed that the Fe-PANI-GA composite had an excellent removal capacity for the removal of U(VI) in acidic solutions. The results also showed that the maximum removal capacity of the Fe-PANI-GA toward U(VI) was 350.47mg/g at pH 5.5. The sorption kinetics data were well-described by pseudo-second-order...
November 15, 2016: Journal of Colloid and Interface Science
E R Edwards, W S Cassata, C A Velsko, C B Yeamans, D A Shaughnessy
Precisely-known fission yield distributions are needed to determine a fissioning isotope and the incident neutron energy in nuclear security applications. 14 MeV neutrons from DT fusion at the National Ignition Facility induce fission in depleted uranium contained in the target assembly hohlraum. The fission yields of Kr isotopes (85m, 87, 88, and 89) are measured relative to the cumulative yield of (88)Kr and compared to previously tabulated values. The results from this experiment and England and Rider are in agreement, except for the (85m)Kr/(88)Kr ratio, which may be the result of incorrect nuclear data...
November 2016: Review of Scientific Instruments
Moritz Bigalke, Andrea Ulrich, Agnes Rehmus, Armin Keller
Mineral phosphorus (P) fertilizers contain contaminants that are potentially hazardous to humans and the environment. Frequent mineral P fertilizer applications can cause heavy metals to accumulate and reach undesirable concentrations in agricultural soils. There is particular concern about Cadmium (Cd) and Uranium (U) accumulation because these metals are toxic and can endanger soil fertility, leach into groundwater, and be taken up by crops. We determined total Cd and U concentrations in more than 400 topsoil and subsoil samples obtained from 216 agricultural sites across Switzerland...
November 28, 2016: Environmental Pollution
Faezeh Fatemi, Saba Miri, Samaneh Jahani
In Acidithiobacillus ferrooxidans, one of the most important bioleaching bacterial species, the proteins encoded by the rus operon are involved in the electron transfer from Fe(2+) to O2. To obtain further knowledge about the mechanism(s) involved in the adaptive responses of the bacteria to growth on the different uranium ore pulp densities, we analyzed the expression of the four genes from the rus operon by real-time PCR, when Acidithiobacillus sp. FJ2 was grown in the presence of different uranium concentrations...
November 24, 2016: Archives of Microbiology
Jorge Henrique Pedrobom, Carlos Eduardo Eismann, Amauri A Menegário, Juliana Aparecida Galhardi, Karen Silva Luko, Thiago de Araujo Dourado, Chang Hung Kiang
The exchange membranes P81 and DE81 and Chelex-100 resin were used to perform in situ speciation of uranium in treated acid mine drainage at the Osamu Utsumi mining site, Poços de Caldas city, Southeast Brazil. To investigate possible chemical modifications in the samples during analysis, the three ligands were deployed in situ and in a laboratory (in lab). The results obtained in situ were also compared to a speciation performed using Visual MINTEQ software. Chelex-100 retained total labile U for a period of up to 48 h...
November 20, 2016: Chemosphere
Sergei M Butorin, Kristina O Kvashnina, Damien Prieur, Murielle Rivenet, Philippe M Martin
The effect of La doping on the electronic structure of U in UO2 was studied using an advanced technique, namely, X-ray absorption spectroscopy (XAS) in the high-energy-resolution fluorescence-detection (HERFD) mode, at the U 3d3/2 (M4) edge. Thanks to a significant reduction of the core-hole lifetime broadening and distinct chemical shifts of the HERFD-XAS lines, the U(v) formation as a result of La doping was identified. The isolated contribution of U(v) in the M4 HERFD-XAS spectrum reveals the so-called charge-transfer satellites due to the U 5f-O 2p hybridization...
November 23, 2016: Chemical Communications: Chem Comm
Juliana Aparecida Galhardi, Rafael García-Tenorio, Inmaculada Díaz Francés, Daniel Marcos Bonotto, Marcelo Pinto Marcelli
The radio-elements (234)U, (235)U, (238)U, (230)Th, (232)Th and (210)Po were characterized in lichens, mosses and ferns species sampled in an adjacent coal mine area at Figueira City, Paraná State, Brazil, due to their importance for the assessment of human exposure related to the natural radioactivity. The coal is geologically associated with a uranium deposit and has been used as a fossil fuel in a thermal power plant in the city. Samples were initially prepared at LABIDRO (Isotopes and Hydrochemistry Laboratory), UNESP, Rio Claro (SP), Brazil...
November 18, 2016: Journal of Environmental Radioactivity
Rajan Jakhu, Rohit Mehra, H M Mittal
The uranium concentration in the drinking water of the residents of the Jaipur and Ajmer districts of Rajasthan has been measured for exposure assessment. The daily intake of uranium from the drinking water for the residents of the study area is found to vary from 0.4 to 123.9 μg per day. For the average uranium ingestion rate of 35.2 μg per day for a long term exposure period of 60 years, estimations have been made for the retention of uranium in different body organs and its excretion with time using ICRP's biokinetic model of uranium...
November 22, 2016: Environmental Science. Processes & Impacts
Eduardo Paredes, Emilie Avazeri, Véronique Malard, Claude Vidaud, Pascal E Reiller, Richard Ortega, Anthony Nonell, Hélène Isnard, Frédéric Chartier, Carole Bresson
The study of the isotopic fractionation of endogen elements and toxic heavy metals in living organisms for biomedical applications, and for metabolic and toxicological studies, is a cutting-edge research topic. This paper shows that human neuroblastoma cells incorporated small amounts of uranium (U) after exposure to 10 µM natural U, with preferential uptake of the (235)U isotope with regard to (238)U. Efforts were made to develop and then validate a procedure for highly accurate n((238)U)/n((235)U) determinations in microsamples of cells...
November 21, 2016: Proceedings of the National Academy of Sciences of the United States of America
Zhuanfang Fred Zhang, Christopher E Strickland, Steven O Link
Surface barrier technology is used to isolate radioactive waste and to reduce or eliminate recharge water to the waste zone for 1000 years or longer. However, the design and evaluation of such a barrier is challenging because of the extremely long design life. After establishing a set of design and performance objectives, a package of design solutions was developed for 1000-year surface barriers over nuclear waste sites. The Prototype Hanford Barrier (PHB) was then constructed in 1994 in the field over an existing waste site as a demonstration...
November 18, 2016: Journal of Environmental Management
Julia Wiktor, Gérald Jomard, Marc Torrent, Marjorie Bertolus
We performed first-principles calculations of the momentum distributions of annihilating electron-positron pairs in vacancies in uranium dioxide. Full atomic relaxation effects (due to both electronic and positronic forces) were taken into account and self-consistent two-component density functional theory schemes were used. We present one-dimensional momentum distributions (Doppler-broadened annihilation radiation line shapes) along with line-shape parameters S and W. We studied the effect of the charge state of the defect on the Doppler spectra...
November 21, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Ralf Haiges, Monica Vasiliu, David A Dixon, Karl O Christe
The reaction between [UO2 F2 ] and an excess of Me3 SiN3 in acetonitrile solution results in fluoride-azide exchange and the uranium(VI) dioxodiazide adduct [UO2 (N3 )2 ⋅CH3 CN] was isolated in quantitative yield. The subsequent reaction of [UO2 (N3 )2 ⋅CH3 CN] with 2,2'-bipyridine (bipy) resulted in the formation of the azido-bridged binuclear complex [(bipy)2 (UO2 )2 (N3 )4 ]. The triazido anion [(bipy)UO2 (N3 )3 ](-) was obtained by the reaction of [UO2 (N3 )2 ⋅CH3 CN] with stoichiometric amounts of bipy and the ionic azide [PPh4 ][N3 ]...
November 12, 2016: Chemistry: a European Journal
Benjamin Scheibe, Stefan S Rudel, Magnus R Buchner, Antti J Karttunen, Florian Kraus
β-Uranium(V) fluoride was reacted with liquid anhydrous hydrogen cyanide to obtain a 1D coordination polymer with the composition 1∞ [UF5 (HCN)2 ], 1∞ [UF4/1 F2/2 - (HCN)2/1 ], revealed by single-crystal X-ray structure determination. The reaction system was furthermore studied by means of vibrational and NMR spectroscopy, as well as by quantum chemical calculations. The compound presents the first described polymeric HCN Lewis adduct and the first HCN adduct of a uranium fluoride.
November 17, 2016: Chemistry: a European Journal
Antonino Gulino, Giuseppe Trusso Sfrazzetto, Salvatrice Millesi, Andrea Pappalardo, Gaetano Tomaselli, Francesco Ballistreri, Rosa Maria Toscano, Luciano Fragalà
We report on an uranyl complex monolayer that easily allows the optical detection of a nervine gas simulant, namely the dimethyl methylphosphonate. Both UV-vis and photoelectronic data confirm that the functional hybrid material coordinates this Lewis basis by means of the P=O group that interacts with the uranium equatorial site available for complexation.
November 16, 2016: Chemistry: a European Journal
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