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Franziska Schmidt, Haruko M Wainwright, Boris Faybishenko, Miles Denham, Carol Eddy-Dilek
This study presents a Kalman filter-based framework to establish a real-time in situ monitoring system for groundwater contamination based on in situ measurable water quality variables, such as specific conductance (SC) and pH. First, this framework uses principal component analysis (PCA) to identify correlations between the contaminant concentrations of interest and in situ measurable variables. It then applies the Kalman filter to estimate contaminant concentrations continuously and in real-time by coupling data-driven concentration-decay models with the previously identified data correlations...
June 22, 2018: Environmental Science & Technology
Carol Sukhn, Johnny Awwad, Akram Ghantous, Ghazi Zaatari
BACKGROUND: Human exposure to environmental pollutants is widespread. It was suggested that exposure to non-essential heavy metals may adversely affect semen development in men. PURPOSE: To evaluate associations between non-essential heavy metals in blood and seminal fluid and semen quality parameters in men. METHODS: Male partners of heterosexual couples were included. The following elements were measured in blood and seminal fluid: lead (Pb), cadmium (Cd), arsenic (As), barium (Ba), mercury (Hg), and uranium (U) using ion-coupled plasma-mass spectrometry...
June 21, 2018: Journal of Assisted Reproduction and Genetics
Gemma Reguera
Geobacter bacteria are the only microorganisms known to produce conductive appendages or pili to electronically connect cells to extracellular electron acceptors such as iron oxide minerals and uranium. The conductive pili also promote cell-cell aggregation and the formation of electroactive biofilms. The hallmark of these electroactive biofilms is electronic heterogeneity, mediated by coordinated interactions between the conductive pili and matrix-associated cytochromes. Collectively, the matrix-associated electron carriers discharge respiratory electrons from cells in multilayered biofilms to electron-accepting surfaces such as iron oxide coatings and electrodes poised at a metabolically oxidizable potential...
July 1, 2018: FEMS Microbiology Ecology
Anne Bauer, Astrid Jäschke, Sebastian Schöne, Robert Barthen, Juliane März, Katja Schmeide, Michael Patzschke, Berthold Kersting, Karim Fahmy, Jana Oertel, Vinzenz Brendler, Thorsten Stumpf
The environmental aspects of ore processing and waste treatment call for an optimization of applied technologies. There, understanding of the structure and complexation mechanism on a molecular scale is indispensable. Here, the complexation of UVI with a calix[4]arene-based 8-hydroxyquinoline ligand was investigated by applying a wide range of complementary methods. In solution, the formation of two complex species was proven with stability constants of log  ß 1:1 =5.94±0.02 and log  ß 2:1 =6.33±0.01, respectively...
June 2018: ChemistryOpen
Carles Fuertes-Espinosa, Alejandra Gómez-Torres, Roser Morales-Martínez, Antonio Rodríguez-Fortea, Cristina García-Simón, Felipe Gándara, Inhar Imaz, Judith Juanhuix, Daniel Maspoch, Josep M Poblet, Luis Echegoyen, Xavi Ribas
Supramolecular nanocapsule 1·(BArF)8 is able to sequentially and selectively entrap recently discovered U2@C80 and unprecedented Sc2CU@C80, simply by soaking crystals of 1·(BArF)8 in a toluene solution of arc-produced soot. These species, selectively and stepwise absorbed by 1·(BArF)8, are easily released, obtaining highly pure fractions of U2@C80 and Sc2CU@C80 in one step. Sc2CU@C80 represents the first example of a mixed metal actinide-based endohedral metallofullerene (EMF). Remarkably, the host-guest studies revealed that 1·(BArF)8 is able to discriminate EMFs with the same carbon cage but with different encapsulated cluster and computational studies provide support for these observations...
June 19, 2018: Angewandte Chemie
Xingliang Li, Zhicheng Zhang, Leigh R Martin, Shunzhong Luo, Linfeng Rao
N-(2-Hydroxyethyl)ethylenediamine- N, N', N'-triacetic acid (HEDTA, denoted as H3 L in this work, and the three dissociable protons represent those of the three carboxylic groups) is a strong chelating ligand and plays an important role in the treatment and disposal of nuclear wastes as well as separation sciences of f-elements. In this work, the complexation of HEDTA with U(VI) was studied thermodynamically and structurally in aqueous solutions. Potentiometry and microcalorimetry were used to measure the complexation constants (298-343 K) and enthalpies (298 K), respectively, at I = 1...
June 19, 2018: Inorganic Chemistry
Xiaomei Wang, Guoxun Ji, Cen Shi, Juan Diwu, Lanhua Chen, Daxiang Gui, Jianmei Wan, Mark A Silver, Jianqiang Wang, Shuao Wang
Deferiprone (3-hydroxy-1,2-dimethyl-4(1H)-pyridone, DFP), which is a drug clinically used for removing heavy metals in vivo, was explored for its removal efficiency towards uranium. The reaction of uranyl nitrate hexahydrate with DFP at room temperature yielded the compound [(UO2)(H2O)(C7NO2H8)2]·4H2O (1), which crystallizes from a mixed solution of methanol and water (pH = 7.0). X-ray diffraction shows that the stable complexation of uranyl occurs from the coordination of two bidentate DFP ligands perpendicular to the O[double bond, length as m-dash]U[double bond, length as m-dash]O unit with a fifth coordinating oxygen atom coming from one water molecule, resulting in a pentagonal bipyramidal geometry...
June 19, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
C A Stitt, C Paraskevoulakos, A Banos, N J Harker, K R Hallam, H Pullin, A Davenport, S Street, T B Scott
To reflect potential conditions in a geological disposal facility, uranium was encapsulated in grout and submersed in de-ionised water for time periods between 2-47 weeks. Synchrotron X-ray Powder Diffraction and X-ray Tomography were used to identify the dominant corrosion products and measure their dimensions. Uranium dioxide was observed as the dominant corrosion product and time dependent thickness measurements were used to calculate oxidation rates. The effectiveness of physical and chemical grout properties to uranium corrosion and mobilisation is discussed and Inductively Coupled Plasma Mass Spectrometry was used to measure 238 U(aq) content in the residual water of several samples...
June 18, 2018: Scientific Reports
Nina Chobanova, Kremena Ivanova, Zdenka Stojanovska, Trayan Atanasov
The indoor radon concentrations and lung cancer incidence in Eleshnitza village and Blagoevgrad district of Bulgaria were examined in the study reported here. The Eleshnitza was the second largest uranium mining and milling region of the country. The geometric mean of indoor radon concentration in Eleshnitza (465 Bq/m3) was higher than the geometric mean of Blagoevgrad district (78 Bq/m3). Retrospective analyses on lung cancer incidence, covering the period 1995-2012 have been shown the same trend. The results were suggestive of an existing relationship between the two variables...
June 15, 2018: Radiation Protection Dosimetry
Ammon Williams, Supathorn Phongikaroon
In this current study, the molten salt aerosol-laser-induced breakdown spectroscopy (LIBS) system was used to measure the uranium (U) content in a ternary UCl3 -LiCl-KCl salt to investigate and assess a near real-time analytical approach for material safeguards and accountability. Experiments were conducted using five different U concentrations to determine the analytical figures of merit for the system with respect to U. In the analysis, three U lines were used to develop univariate calibration curves at the 367...
January 1, 2018: Applied Spectroscopy
Hilary P Emerson, Silvina Di Pietro, Yelena Katsenovich, Jim Szecsody
Temporary base treatment is a potential remediation technique for heavy metals through adsorption, precipitation, and co-precipitation with minerals. Manipulation of pH with ammonia gas injection may be especially useful for vadose zone environments as it does not require addition of liquids that would increase the flux towards groundwater. In this research, we conducted laboratory batch experiments to evaluate the changes in uranium mobility and mineral dissolution with base treatments including sodium hydroxide, ammonium hydroxide, and ammonia gas...
June 13, 2018: Journal of Environmental Management
Aili Yang, Yukuan Zhu, C P Huang
To overcome the limits of low adsorption capacity and the separation difficulty of solid from liquid phase for graphene oxide (GO), a novel nanocomposite graphene oxide-manganese oxide (GOMO) was facilely fabricated under ultrasonic radiation. The structures and micro-morphology of the products were characterized by fourier transform infrared (FT-IR) spectroscopy, raman shift spectroscopy, X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM). The effect of solution pH, adsorbent dose, contact time, initial uranium concentration, ionic strength and temperature on uranium removal efficiency was studied by batch adsorption experiments...
June 13, 2018: Scientific Reports
K Arumugam, S Srinivasalu, R Purvaja, R Ramesh
From koppunuru study area totally 58 samples were collected in 7 different boreholes, minimum depth of 28 m and Maximum depth of 157.7 m. The borehole samples geochemical analysis (major and trace elements) was carried out at Atomic Minerals Directorate for Exploration & Research (AMD), Hyderabad, India. Major and trace element studies have been conducted on the Neoproterozoic Palnad sub-basin Andhra Pradesh, South India, to determine their Geochemistry, Uranium mineralization and provenance characteristics...
June 2018: Data in Brief
R García-Tenorio, G Manjón, I Vioque, M C Jiménez-Ramos, J Mantero, I Díaz-Francés
A radiological evaluation associated to the future mining of grey monazite nodules enriched in light rare-earths, from a modest superficial deposit located in the centre of Spain, has been performed at pre-operational level, and the main results are shown in this paper. Although the monazite nodules in the deposit are clearly enriched in radionuclides from the uranium and thorium series with activity concentrations higher than 1 Bq/g, the size of these nodules (in the 0.5 mm-2 mm grain size interval), its refractory behaviour that prevents the leaching or dissemination of natural radionuclides to waters or other ecosystem compartments and consequently the impact in the food chain, and its presence quite diluted in the deposit at concentrations of 2...
June 5, 2018: Chemosphere
Benoit Nemery, Célestin Banza Lubaba Nkulu
In this narrative account based on a keynote presentation on exposure biomonitoring of metals in low- and middle-income countries (LMIC), we first briefly address practical issues that have arisen from our experience during the conduct of various surveys in LMIC. These have included the statistical handling of multiple pollutants in the same subject, the problem of correctly adjusting for urinary flow in spot samples of urine, and the possible external contamination of samples when doing field surveys in challenging environments...
June 9, 2018: Toxicology Letters
Larisa Bešić, Imer Muhović, Fatima Mrkulić, Lemana Spahić, Ammar Omanović, Amina Kurtovic-Kozaric
Since the first widespread use of depleted uranium in military in the 1991 Gulf War, the so-called "Gulf War Syndrome" has been a topic of ongoing debate. However, a low number of reliable scientific papers demonstrating the extent of possible contamination as well as its connection to the health status of residents and deployed veterans has been published. The authors of this study have therefore aimed to make a selection of data based on strict inclusion and exclusion criteria. With the goal of clarifying the extent of DU contamination after the Gulf Wars, previously published data regarding the levels of DU in the Middle East region were analyzed and presented in the form of a meta-analysis...
June 8, 2018: Journal of Environmental Radioactivity
Quang Anh Tuan Le, Hee Gon Kim, Yong Hwan Kim
The electro-biocatalytic conversion of CO2 into formic acid using whole-cell and isolated biocatalysts is useful as an alternative route for CO2 sequestration. In this study, Shewanella oneidensis MR-1 (S. oneidensis MR-1), a facultative aerobic bacterium that has been extensively studied for its utility as biofuel cells as well as for the detoxification of heavy metal oxides (i.e., MnO2 , uranium), has been applied for the first time as a whole-cell biocatalyst for formic acid synthesis from gaseous CO2 and electrons supplied from an electrode...
September 2018: Enzyme and Microbial Technology
Anna Maria Orani, Emilia Vassileva, Irena Wysocka, Michael Angelidis, Martina Rozmaric, Deon Louw
Namibia is a fast-growing country with extensive mineral extraction activities used in diamond, fluorspar, uranium, and metals production. To assess the impact of land based human activities on the Namibian coastal marine environment, 25 elements were analyzed in 22 surface sediments samples collected along the coast. After applying a variety of pollution assessment indices (Enrichment Factor, Igeo and Pollution Load Indexes) was concluded that As, Cd and Sb were considerably enriched in the sediments from several sites, while Cu, Pb and Zn showed very high enrichment near the Walvis Bay harbor...
June 2018: Marine Pollution Bulletin
Lingjun Kong, Huimin Zhang, Kaimin Shih, Minhua Su, Zenghui Diao, Jianyou Long, Li'an Hou, Gang Song, Diyun Chen
The abundant generation of uranium (U), a radioactive nuclide, engenders a severe hazard to the environment. Iron based materials were used to immobilize U from water, however, the immobilization is limited by the agglomeration of nanoparticle Fe. In this study, a novel carbothermal process was proposed to synthesize flour carbon (FC) supported nano-flake Fe (Fe-FC). Scanning electron microscopy (SEM) and nitrogen isotherm adsorption-desorption analysis were conducted to characterize Fe-FC. The immobilization characteristics were investigated through batch sorption experiments...
May 30, 2018: Journal of Hazardous Materials
Rong Li, Yuna Li, Maojiang Zhang, Zhe Xing, Hongjuan Ma, Guozhong Wu
This work provides a cost-effective approach for preparing functional polymeric fibers used for removing uranium (U(VI)) from carbonate solution containing NaF. Phosphate-based ultrahigh molecular weight polyethylene (UHMWPE-g-PO₄) fibers were developed by grafting of glycidyl methacrylate, and ring-opening reaction using phosphoric acid. Uranium (U(VI)) adsorption capacity of UHMWPE-g-PO₄ fibers was dependent on the density of phosphate groups (DPO , mmol∙g−1 ). UHMWPE-g-PO₄ fibers with a DPO of 2...
May 23, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
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