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Environmental Science. Processes & Impacts

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January 17, 2017: Environmental Science. Processes & Impacts
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No abstract text is available yet for this article.
January 17, 2017: Environmental Science. Processes & Impacts
John J MacInnis, Katherine French, Derek C G Muir, Christine Spencer, Alison Criscitiello, Amila O De Silva, Cora J Young
To improve understanding of long-range transport of perfluoroalkyl substances to the High Arctic, samples were collected from a snow pit on the Devon Ice Cap in spring 2008. Snow was analyzed for perfluoroalkyl acids (PFAAs), including perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs), as well as perfluorooctane sulfonamide (FOSA). PFAAs were detected in all samples dated from 1993 to 2007. PFAA fluxes ranged from <1 to hundreds of ng per m(2) per year. Flux ratios of even-odd PFCA homologues were mostly between 0...
January 16, 2017: Environmental Science. Processes & Impacts
Angela R Lemons, Mary Beth Hogan, Ruth A Gault, Kathleen Holland, Edward Sobek, Kimberly A Olsen-Wilson, Yeonmi Park, Ju-Hyeong Park, Ja Kook Gu, Michael L Kashon, Brett J Green
Recent studies conducted in the Great Basin Desert region of the United States have shown that skin test reactivity to fungal and dust mite allergens are increased in children with asthma or allergy living in homes with evaporative coolers (EC). The objective of this study was to determine if the increased humidity previously reported in EC homes leads to varying microbial populations compared to homes with air conditioners (AC). Children with physician-diagnosed allergic rhinitis living in EC or AC environments were recruited into the study...
January 16, 2017: Environmental Science. Processes & Impacts
Govinda Chilkoor, Venkata K K Upadhyayula, Venkataramana Gadhamshetty, Nikhil Koratkar, Mats Tysklind
Biodiesel is a widely used fuel that meets the renewable fuel standards developed under the Energy Policy Act of 2005. However, biodiesel is known to pose a series of abiotic and biotic corrosion risks to storage tanks. A typical practice (incumbent system) used to protect the tanks from these risks include (i) coating the interior surface of the tank with a solvent-free epoxy (SFE) liner, and (ii) adding a biocide to the tank. Herein, we present a screening-level life-cycle assessment study to compare the environmental performance of a graphene oxide (GO)-epoxy (GOE) liner with the incumbent system...
January 16, 2017: Environmental Science. Processes & Impacts
A Salmela, V Lappalainen, T Reponen, P Pasanen
Fungal biomass can be determined by measuring the beta-N-acetylhexos-aminidase (NAHA) enzyme activity. NAHA, an enzyme present in fungal mycelium and spores, has been detected in inactive, dormant and non-viable cells. Very little information is available on the enzyme activity of different species or retention of the activity under various storage conditions. This study used fluorometry to evaluate the enzyme activity of liquid and filter samples containing spores of four fungal species from genera Penicillium, Cladosporium, Aspergillus, and Acremonium...
January 12, 2017: Environmental Science. Processes & Impacts
L K Sviatenko, L Gorb, D Leszczynska, S I Okovytyy, M K Shukla, J Leszczynski
Alkaline hydrolysis of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), as one of the most promising methods for nitrocompound remediation, was investigated computationally at the PCM(Pauling)/M06-2X/6-311++G(d,p) level of theory. Computational simulation shows that RDX hydrolysis is a highly exothermic multistep process involving initial deprotonation and nitrite elimination, cycle cleavage, further transformation of cycle-opened intermediates to end products caused by a series of C-N bond ruptures, hydroxide attachments, and proton transfers...
January 12, 2017: Environmental Science. Processes & Impacts
S Mogo, J F López, V E Cachorro, A de Frutos, R Zocca, A Barroso, D Mateos, E Conceição
Continuous measurements of the optical properties of aerosol particles have been made at Valladolid, Spain, covering the period from June 2011 to July 2012. The measurements were made at two size cuts: sub-10 μm and sub-1 μm (PM10 and PM1). The data measured were the scattering and backscattering coefficients, σs and σbs, obtained from an integrating nephelometer, and the absorption coefficient, σa, obtained from a particle soot absorption photometer. Spectrally resolved data were obtained from both instruments at 3 wavelengths (blue/green/red) at low relative humidity (RH < 40%)...
January 12, 2017: Environmental Science. Processes & Impacts
Zeyuan Chen, Cort Anastasio
Photochemical reactions influence the fates and lifetimes of organic compounds in snow and ice, both through direct photoreactions and via photoproduced transient species such as hydroxyl radical (˙OH) and, perhaps, triplet excited states of organic compounds (i.e., triplets). While triplets can be important oxidants in atmospheric drops and surface waters, little is known of this class of oxidants in frozen samples. To investigate this, we examined the photoreaction of phenol with the triplet state of 3,4-dimethoxybenzaldehyde ((3)DMB*), a product from biomass combustion, in illuminated laboratory ices...
January 6, 2017: Environmental Science. Processes & Impacts
Shirin Shafaei, Nikolaus Klamerth, Yanyan Zhang, Kerry McPhedran, James R Bolton, Mohamed Gamal El-Din
Photoreactivation is a process where ultraviolet (UV)-induced damage to the DNA of microorganisms can be reversed by exposure to near UV and visible light. To date, most photoreactivation experiments have been carried out under laboratory conditions using standard microorganisms that do not reflect the natural conditions of municipal wastewater effluents. Photoreactivation could increase the concentration of pathogens released into natural systems, leading to negative impacts on fish, shellfish, and clams. In addition, pathogen release can increase health risks of downstream activities, such as swimming...
January 4, 2017: Environmental Science. Processes & Impacts
Bao-Nan He, Jiang-Tao He, Jian Wang, Jie Li, Fei Wang
The pH is a primary index reflecting water quality in rivers. The Jian River and Chaobai River are two reclaimed water intake areas which have elevated pH. This elevated pH has a marked effect on both the phytoplankton, species in water and vegetation on the shore. Understanding the main reasons causing pH elevation in river water has important implications for river ecosystem management and the improvement of water quality and can provide a theoretical basis for the direction of water quality improvement. For this reason, each biogeochemical and physical process influencing pH changes in water was quantified along the flow direction in the Wenyu to Chaobai reclaimed water diversion project, in which proton consumption and production by such processes were monitored and calculated at five monitoring sections...
December 23, 2016: Environmental Science. Processes & Impacts
Peta A Neale, Maud E S Achard, Beate I Escher, Frederic D L Leusch
Environmental waters can contain a wide range of micropollutants. Bioanalytical test batteries using assays indicative of different stages of cellular toxicity pathways, such as adaptive stress responses, have been applied to a range of water samples. Oxidative stress response assays have proven to be sensitive tools, but the mechanism by which water samples are inducing the oxidative stress response remains unclear because both electrophiles and reactive oxygen species (ROS) may activate the Nrf2-antioxidant response element (ARE) pathway...
December 22, 2016: Environmental Science. Processes & Impacts
Lukas Linden, Kai-Uwe Goss, Satoshi Endo
Ionic organic chemicals are a class of chemicals that is released in the environment in a large amount from anthropogenic sources. Among various chemical and biological processes, binding to serum albumin is particularly relevant for the toxicokinetic behavior of ionic chemicals. Several experimental studies showed that steric effects have a crucial influence on the sorption to bovine serum albumin (BSA). In this study, we investigated whether a 3D quantitative structure-activity relationship (3D-QSAR) model can accurately account for these steric effects by predicting the BSA-water partition coefficients (KBSA/water) of neutral and anionic organic chemicals...
December 22, 2016: Environmental Science. Processes & Impacts
Hailiang Zhao, Lin Du
In this study, the stability of clusters formed by the trans- and cis-isomers of nitrous acid (HONO) with dimethylamine (DMA) and water has been characterized by density functional theory. The large red shifts of the OH-stretching transitions of both HONO isomers in the clusters indicate the formation of strong hydrogen bonds. At standard temperature and pressure, H2O (acceptor) binds to HONO (donor) with binding energies of -25.0 to -24.6 kJ mol(-1), less stable than those of DMA (acceptor) with HONO (donor) (-50...
December 22, 2016: Environmental Science. Processes & Impacts
T Moreno, X Querol, V Martins, M C Minguillón, C Reche, L H Ku, H R Eun, K H Ahn, M Capdevila, E de Miguel
Most particles in the rail subway environment are sub-micron sized ferruginous flakes and splinters generated mechanically by frictional wear of brake pads, wheels and rails. To better understand the mechanisms of formation and the alteration processes affecting inhalable particles in subways, PM samples (1-2.5 μm and 2.5-10 μm) were collected in the Barcelona Metro and then studied under a scanning electron microscope. Most particles in these samples are hematitic (up to 88%), with relatively minor amounts of mineral matter (up to 9%) and sulphates (up to 5%)...
December 21, 2016: Environmental Science. Processes & Impacts
Goran Kovacevic, Aleksandar Sabljic
Atmospheric transport is the major route for global distribution of semi-volatile compounds such as halogenated aromatics as well as their major exposure route for humans. Their major atmospheric removal process is oxidation by hydroxyl radicals. There is very little information on the reaction mechanism or reaction-path dynamics of atmospheric degradation of halogenated benzenes. Furthermore, the measured reaction rate constants are missing for the range of environmentally relevant temperatures, i.e. 230-330 K...
December 21, 2016: Environmental Science. Processes & Impacts
Hang Yu, Jingwen Chen, Hongbin Xie, Pu Ge, Qingwei Kong, Yi Luo
Ferrate(vi) is an efficient and environmentally friendly oxidant for the degradation of organic micropollutants. However, the related mechanism for the degradation is ambiguous and can hardly be elucidated empirically due to the rapid oxidation process and unstable intermediates for experimental trapping. Herein we performed density function theory (DFT) calculations to unveil the mechanism of ferrate(vi)-mediated degradation, taking sulfamethoxazole as a model compound. The results show that nucleophilic attack (rather than electrophilic attack) of HFeO4(-) on the isoxazole moiety of sulfamethoxazole initiates the subsequent degradations, and ferrate(vi) rather than the water molecule provides O atoms for the oxidation of the nitroso group and isoxazole moiety...
December 12, 2016: Environmental Science. Processes & Impacts
William A Arnold, Yan Oueis, Meghan O'Connor, Johanna E Rinaman, Miranda G Taggart, Rachel E McCarthy, Kimberley A Foster, Douglas E Latch
Quantitative structure-activity relationships (QSARs) for prediction of the reaction rate constants of phenols and phenolates with three photochemically produced oxidants, singlet oxygen, carbonate radical, and triplet excited state sensitizers/organic matter, are developed. The predictive variable is the one-electron oxidation potential (E1), which is calculated for each species using density functional theory. The reaction rate constants are obtained from the literature, and for singlet oxygen, are augmented with new experimental data...
December 12, 2016: Environmental Science. Processes & Impacts
P Dranguet, S Le Faucheur, C Cosio, V I Slaveykova
Mercury (Hg) is a pollutant of high concern for aquatic systems due to the biomagnification of its methylated form along the food chain. However, in contrast to other metals, gaining knowledge of its bioavailable forms for aquatic microorganisms remains challenging, making Hg risk assessment difficult. Ubiquitous and sessile freshwater biofilms are well known to accumulate and to transform Hg present in their ambient environment. The present study thus aims to evaluate whether non-extractable (proxy of intracellular) Hg accumulated by biofilms could be a good indicator of Hg bioavailability for microorganisms in freshwater...
December 12, 2016: Environmental Science. Processes & Impacts
O W Duckworth, N A Rivera, T G Gardner, M Y Andrews, C M Santelli, M L Polizzotto
Manganese oxides, which may be biogenically produced in both pristine and contaminated environments, have a large affinity for many trace metals. In this study, water and Mn oxide-bearing biofilm samples were collected from the components of a pump and treat remediation system at a superfund site. To better understand the factors leading to their formation and their effects on potentially toxic metal fate, we conducted a chemical, microscopic, and spectroscopic characterization of these biofilm samples. Scanning electron microscopy revealed the presence of Mn oxides in close association with biological structures with morphologies consistent with fungi...
December 12, 2016: Environmental Science. Processes & Impacts
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