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Ashis Biswas, M Jim Hendry, Joseph Essilfie-Dughan
This study investigated the geochemistry of arsenic (As) in low sulfide-high carbonate coal waste rock of the Elk Valley, British Columbia, Canada. Its abundance and mineralogical associations in waste rock of different placement periods were determined in addition to its mobilization into porewater and rock-drain effluent. The mean (5.34mg/kg; 95% confidence interval: 4.95-5.73mg/kg) As concentration in the waste rock was typical of sedimentary rock. Electron microprobe and As K-edge X-ray absorption near-edge spectroscopic analyses showed the As is predominantly associated with primary pyrites in both source and freshly blasted waste rock...
November 24, 2016: Science of the Total Environment
Marek Kosmulski
The pH-dependent surface charging of metal (hydr)oxides is reviewed on the occasion of the 50th anniversary of the publication by G.A. Parks: "Isoelectric points of solid oxides, solid hydroxides, and aqueous hydroxo complex systems" in Chemical Reviews. The point of zero charge (PZC) and isoelectric point (IEP) became standard parameters to characterize metal oxides in aqueous dispersions, and they define adsorption (surface excess) of ions, stability against coagulation, rheological properties of dispersions, etc...
November 5, 2016: Advances in Colloid and Interface Science
Zenhom El-Said Salem, Osman M Osman
The aim of this research is to evaluate the groundwater geochemistry in western Nile Delta area as an example of an aquifer influenced by reclamation and seawater intrusion. To conduct this study, 63 groundwater samples and one surface water sample from El Nubaria Canal were collected. To estimate the origin of dissolved ions and the geochemical processes influencing this groundwater, integration between land use change, pedological, hydrogeological, hydrogeochemical, and statistical approaches was considered...
November 25, 2016: Environmental Science and Pollution Research International
Delia Rodríguez-Oroz, Esther Lasheras, David Elustondo, Jordi Garrigó
The objective of the present work was to verify and compare the performance of different geochemical indices employed to identify the anthropogenic origin of selected heavy metals and other trace elements in soils. To that end, two background values, the upper continental crust and the metal content in the bed rock, were used and obtained from a forested basin of the western Pyrenees. The enrichment factor (EF), geo-accumulation index (Igeo), and contamination factor (C(i)f) were finally evaluated for their ability to determine anthropogenic contamination: Results indicate that an in-depth knowledge of the bed rock geochemistry and the geological background content is essential to distinguish between the natural variability of soils and any anthropogenic contribution of heavy metals...
November 24, 2016: Bulletin of Environmental Contamination and Toxicology
G Clark, I Cohen, J H Westlake, G B Andrews, P Brandt, R E Gold, M A Gkioulidou, R Hacala, D Haggerty, M E Hill, G C Ho, S E Jaskulek, P Kollmann, B H Mauk, R L McNutt, D G Mitchell, K S Nelson, C Paranicas, N Paschalidis, C E Schlemm
Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly capable, mass-species-discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the "Puck" EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of ~10 keV to several MeV...
August 2016: Journal of Geophysical Research. Space Physics
Jörg Schaller, Jonas Schoelynck, Mike Murray-Hudson, Patrick J Frings, Dimitri van Pelt, Tilo Hegewald, Keotshephile Mosimane, Mangaliso Gondwe, Piotr Wolski, Patrick Meire, Eric Struyf
Wetlands fed by rivers can be a sink for elements depending on elemental concentrations, wetland hydrology, geochemistry, vegetation and climate. In the case of the Okavango Delta, northern Botswana, the outflow discharge is a small fraction (2-5%) of the inflow. This has strong potential consequences for the Delta, as it strongly affects element cycling and storage within the Delta. We estimated the inputs, behaviour and distribution of multiple elements along a longitudinal transect within the Okavango Delta, to show potential effects of retention mechanisms of different elements...
December 0: Environmental Monitoring and Assessment
Pablo Hernández-Morales, Jobst Wurl
The existence of hot springs in the northeastern part of Los Cabos Baja California Sur (BCS), is known from pre-Hispanic times, but their hydrochemical composition had not been previously described. Several springs are located within the watershed of Santiago, and the objective of this study was to define the hydrogeochemical composition of the thermal springs and to characterize the geothermal reservoir. A total of 16 water samples were taken in 11 geothermal manifestations under dry (June 2014) and humid (March 2015) conditions...
November 19, 2016: Environmental Science and Pollution Research International
David C Magri, Alex D Johnson, Jake C Spiteri
This mini-review highlights the photophysical properties of fluorescent molecular logic gates responsive to acids and oxidants, particularly those developed in our laboratory the past few years. The review pays tribute to earlier developments that lay the foundation for this emerging class of molecules. The logic gates incorporate design concepts based on photoinduced electron transfer from the cross-fertilization of the fluorophore-spacer-receptor and fluorophore-spacer-electron-donor formats. The molecular logic gates explored in detail consist of anthracene and/or naphthalimide fluorophores, while the receptor and electron-donor are typically alkyl amines and ferrocene, respectively...
November 16, 2016: Journal of Fluorescence
David Dolejš
No abstract text is available yet for this article.
November 16, 2016: Nature
(no author information available yet)
No abstract text is available yet for this article.
November 16, 2016: Nature
Antony van der Ent, Mansour Edraki
The Mamut Copper Mine (MCM) located in Sabah (Malaysia) on Borneo Island was the only Cu-Au mine that operated in the country. During its operation (1975-1999), the mine produced 2.47 Mt of concentrate containing approximately 600,000 t of Cu, 45 t of Au and 294 t of Ag, and generated about 250 Mt of overburden and waste rocks and over 150 Mt of tailings, which were deposited at the 397 ha Lohan tailings storage facility, 15.8 km from the mine and 980 m lower in altitude. The MCM site presents challenges for environmental rehabilitation due to the presence of large volumes of sulphidic minerals wastes, the very high rainfall and the large volume of polluted mine pit water...
November 15, 2016: Environmental Geochemistry and Health
P T Schwing, B J O'Malley, I C Romero, M Martínez-Colón, D W Hastings, M A Glabach, E M Hladky, A Greco, D J Hollander
Following the Deepwater Horizon (DWH) event in 2010 subsurface hydrocarbon intrusions (1000-1300 m) and an order of magnitude increase in flocculent hydrocarbon deposition caused increased concentrations of hydrocarbons in continental slope sediments. This study sought to characterize the variability [density, Fisher's alpha (S), equitability (E), Shannon (H)] of benthic foraminifera following the DWH event. A series of sediment cores were collected at two sites in the northeastern Gulf of Mexico from 2010 to 2012...
November 11, 2016: Environmental Science and Pollution Research International
Ivan Sondi, Nevenka Mikac, Neda Vdović, Maja Ivanić, Martina Furdek, Srečo D Škapin
This study investigates the geochemical characteristics of recent shallow-water aragonite-rich sediments from the karstic marine lakes located in the pristine environment on the island of Mljet (Adriatic Sea). Different trace elements were used as authigenic mineral formation, palaeoredox and pollution indicators. The distribution and the historical record of trace elements deposition mostly depended on the sedimentological processes associated with the formation of aragonite, early diagenetic processes governed by the prevailing physico-chemical conditions and on the recent anthropogenic activity...
November 8, 2016: Chemosphere
D Mondal, S Gupta, D V Reddy, G Dutta
This research work primarily deals with the geochemistry and genesis of fluoride (F(-)) in an alluvial aquifer with an emphasis on prevalence of dental and skeletal fluorosis among the endemic population. Hydrogeochemical outcomes reveal that chemical weathering and ion-exchange phenomena are the two dominant processes that make study area groundwater into NaHCO3 water type. Presence of intercalated zeolite rich sediments (FTotal 412-446 mg/kg) having higher ion-exchange capacity (120-125 meq/100 g) within the aquifer is the source and mobilizing factors of F(-) in groundwater respectively...
November 8, 2016: Chemosphere
Daniel N Baker, Ryan M Dewey, David J Lawrence, John O Goldsten, Patrick N Peplowski, Haje Korth, James A Slavin, Stamatios M Krimigis, Brian J Anderson, George C Ho, Ralph L McNutt, Jim M Raines, David Schriver, Sean C Solomon
The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission to Mercury has provided a wealth of new data about energetic particle phenomena. With observations from MESSENGER's Energetic Particle Spectrometer, as well as data arising from energetic electrons recorded by the X-Ray Spectrometer and Gamma-Ray and Neutron Spectrometer (GRNS) instruments, recent work greatly extends our record of the acceleration, transport, and loss of energetic electrons at Mercury. The combined data sets include measurements from a few keV up to several hundred keV in electron kinetic energy and have permitted relatively good spatial and temporal resolution for many events...
March 2016: Journal of Geophysical Research. Space Physics
Patrick N Peplowski, Andrew W Beck, David J Lawrence
Thermal neutron emissions from the lunar surface provide a direct measure of bulk elemental composition that can be used to constrain the chemical properties of near-surface (depth <1 m) lunar materials. We present a new calibration of the Lunar Prospector thermal neutron map, providing a direct link between measured count rates and bulk elemental composition. The data are used to examine the chemical and mineralogical composition of the lunar surface, with an emphasis on constraining the plagioclase concentration across the highlands...
March 2016: Journal of Geophysical Research. Planets
Christopher T Brown, Matthew R Olm, Brian C Thomas, Jillian F Banfield
Culture-independent microbiome studies have increased our understanding of the complexity and metabolic potential of microbial communities. However, to understand the contribution of individual microbiome members to community functions, it is important to determine which bacteria are actively replicating. We developed an algorithm, iRep, that uses draft-quality genome sequences and single time-point metagenome sequencing to infer microbial population replication rates. The algorithm calculates an index of replication (iRep) based on the sequencing coverage trend that results from bi-directional genome replication from a single origin of replication...
November 7, 2016: Nature Biotechnology
Li Jian, Yu Junyi, Liu Jingchun, Yan Chongling, Lu Haoliang, Kate L Spencer
P (phosphorus) and Fe (iron) are limiting elements and S (sulfur) is an important element of the biogeochemical cycle in the mangrove environment. To assess the effects of sulfur on the geochemical cycling of Fe and P at the sediment-plant interface, the speciation distributions of Fe, P and S in sediments were examined. The data showed that higher proportions of amorphous Fe, Fe-bound phosphate, chromium reducible sulfur and elemental sulfur were found in the rhizosphere, while more crystalline Fe, exchangeable phosphate and acid-volatile sulfide were determined in the non-rhizosphere...
November 3, 2016: Marine Pollution Bulletin
Xiaoben Jiang, Cristina D Takacs-Vesbach
The pH of the majority of thermal springs in Yellowstone National Park (YNP) is from 1 to 3 and 6 to 10; relatively few springs (~5%) have a pH range of 4-5. We used 16S rRNA gene pyrosequencing to investigate microbial communities sampled from four pH 4 thermal springs collected from four regions of YNP that differed in their fluid temperature and geochemistry. Our results revealed that the composition of bacterial communities varied among the sites, despite sharing similar pH values. The taxonomic composition and metabolic functional potential of the site with the lowest temperature (55 °C), a thermal spring from the Seven Mile Hole (SMH) area, were further investigated using shotgun metagenome sequencing...
November 2, 2016: Extremophiles: Life Under Extreme Conditions
Kirsty High, Nicky Milner, Ian Panter, Beatrice Demarchi, Kirsty E H Penkman
Examples of wetland deposits can be found across the globe and are known for preserving organic archaeological and environmental remains that are vitally important to our understanding of past human-environment interactions. The Mesolithic site of Star Carr (Yorkshire, United Kingdom) represents one of the most influential archives of human response to the changing climate at the end of the last glacial in Northern Europe. A hallmark of the site since its discovery in 1948 has been the exceptional preservation of its organic remains...
October 31, 2016: Proceedings of the National Academy of Sciences of the United States of America
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