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Chemical speciation

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https://www.readbyqxmd.com/read/28225906/the-current-status-of-the-lutzomyia-longipalpis-diptera-psychodidae-phlebotominae-species-complex
#1
Nataly A Souza, Reginaldo P Brazil, Alejandra S Araki
Lutzomyia longipalpis s.l. is a complex of sibling species and is the principal vector of American visceral leishmaniasis. The present review summarises the diversity of efforts that have been undertaken to elucidate the number of unnamed species in this species complex and the phylogenetic relationships among them. A wide variety of evidence, including chemical, behavioral and molecular traits, suggests very recent speciation events and complex population structure in this group. Although significant advances have been achieved to date, differential vector capacity and the correlation between structure of parasite and vector populations have yet to be elucidated...
March 2017: Memórias do Instituto Oswaldo Cruz
https://www.readbyqxmd.com/read/28225102/stability-of-reverse-micelles-in-rare-earth-separation-a-chemical-model-based-on-a-molecular-approach
#2
Yushu Chen, Magali Duvail, Philippe Guilbaud, Jean-François Dufrêche
Molecular complexes formed in the organic phase during solvent extraction may self-assemble as reverse micelles, and therefore induce a supramolecular organization of this phase. In most of the cases, water molecules play an essential role in the organization of this non polar medium. The aim of this work is to investigate the speciation of the aggregates formed in the organic phase during solvent extraction, and especially to assess their stability as a function of the number of water molecules included in their polar core...
February 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28224666/refinement-and-cross-validation-of-nickel-bioavailability-in-pnec-pro-a-regulatory-tool-for-site-specific-risk-assessment-of-metals-in-surface-water
#3
Anja J Verschoor, Martina G Vijver, Jos P M Vink
The European Water Framework Directive prescribes that the environmental quality standards for nickel in surface waters should be based on bioavailable concentrations. Biotic ligand models (BLMs) are powerful tools to account for site-specific bioavailability within risk assessments. Several BLMs and simplified tools are available. For nickel, most of them are based on the same toxicity dataset and chemical speciation methodology as laid down in the 2008 European Union Environmental-Risk Assessment Report (RAR)...
February 22, 2017: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/28216663/the-importance-of-pollen-chemistry-in-evolutionary-host-shifts-of-bees
#4
Maryse Vanderplanck, Nicolas J Vereecken, Laurent Grumiau, Fabiana Esposito, Georges Lognay, Ruddy Wattiez, Denis Michez
Although bee-plant associations are generally maintained through speciation processes, host shifts have occurred during evolution. Understanding shifts between both phylogenetically and morphologically unrelated plants (i.e., host-saltation) is especially important since they could have been key processes in the origin and radiation of bees. Probably far from being a random process, such host-saltation might be driven by hidden constraints associated with plant traits. We selected two clades of oligolectic bees (i...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28215804/pyrogenic-carbon-in-australian-soils
#5
Fangjie Qi, Ravi Naidu, Nanthi S Bolan, Zhaomin Dong, Yubo Yan, Dane Lamb, Thomas D Bucheli, Girish Choppala, Luchun Duan, Kirk T Semple
Pyrogenic carbon (PyC), the combustion residues of fossil fuel and biomass, is a versatile soil fraction active in biogeochemical processes. In this study, the chemo-thermal oxidation method (CTO-375) was applied to investigate the content and distribution of PyC in 30 Australian agricultural, pastoral, bushland and parkland soil with various soil types. Soils were sampled incrementally to 50cm in 6 locations and at another 7 locations at 0-10cm. Results showed that PyC in Australian soils typically ranged from 0...
February 16, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28213306/phosphorous-extractability-and-ryegrass-availability-from-bio-waste-composts-in-a-calcareous-soil
#6
Marco Grigatti, Elisa Boanini, Silvia Mancarella, Andrea Simoni, Massimo Centemero, Adrie H M Veeken
In this work four stable bio-waste composts (C1, C2, C3, C4) were selected on the basis of their increasing water soluble P (H2O-P). The P speciation was assessed via sequential chemical extraction (SCE) on the same products. Moreover, the plant-available P was assessed via apparent recovery fraction approach (ARF) in a pot test on ryegrass over 21 weeks at 15 mg P kg(-)(1) of soil. An inorganic P source (P-chem) was added as a reference at the same P rate in addition to a non-fertilized control (Control)...
February 6, 2017: Chemosphere
https://www.readbyqxmd.com/read/28208090/multi-approach-characterization-of-organic-sediment-produced-by-an-anaerobic-digestion-plant-fed-with-pig-slurry-and-stored-for-a-long-term-in-a-lagoon
#7
Anna Ricci, Luisa Massaccesi, Daniela Pezzolla, Giuseppe Corti, Alberto Agnelli, Giovanni Gigliotti
This study combined different approaches to characterize organic sediments produced by an anaerobic digestion plant feed with pig slurry, and accumulated for many years in a lagoon. The results of all analyses identified a certain homogeneity of the sediments. As a consequence of the pig diet, the sediment contained an high concentration of Zn (about 4gkg(-1)) and Cu (about 1.2gkg(-1)), which were mostly associated to the particles with a size ranging from 2 to 53μm. The sediment was made of large amount of organic matter, mostly cellulose and recalcitrant molecules, and 30-40% mineral fraction...
February 5, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28205587/nickel-biopathways-in-tropical-nickel-hyperaccumulating-trees-from-sabah-malaysia
#8
Antony van der Ent, Damien L Callahan, Barry N Noller, Jolanta Mesjasz-Przybylowicz, Wojciech J Przybylowicz, Alban Barnabas, Hugh H Harris
The extraordinary level of accumulation of nickel (Ni) in hyperaccumulator plants is a consequence of specific metal sequestering and transport mechanisms, and knowledge of these processes is critical for advancing an understanding of transition element metabolic regulation in these plants. The Ni biopathways were elucidated in three plant species, Phyllanthus balgooyi, Phyllanthus securinegioides (Phyllanthaceae) and Rinorea bengalensis (Violaceae), that occur in Sabah (Malaysia) on the Island of Borneo. This study showed that Ni is mainly concentrated in the phloem in roots and stems (up to 16...
February 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28202264/characteristics-and-source-appointment-of-atmospheric-particulate-mercury-over-east-china-sea-implication-on-the-deposition-of-atmospheric-particulate-mercury-in-marine-environment
#9
Lian Duan, Na Cheng, Guangli Xiu, Fujiang Wang, Ying Chen
Total Suspended Particulate (TSP) samples were collected at Huaniao Island in northern East China Sea (ECS) from March 2012 to January 2013. Chemical analysis were conducted to measure the concentration of total particulate mercury (TPM) and speciated particulate mercury including HCl-soluble particulate mercury (HPM), elemental particulate mercury (EPM) and residual particulate mercury (RPM). The bromine (Br) and iodine (I) on particles were also detected. The mean concentration of TPM during the study period was 0...
February 12, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28197603/general-baseline-toxicity-qsar-for-nonpolar-polar-and-ionisable-chemicals-and-their-mixtures-in-the-bioluminescence-inhibition-assay-with-aliivibrio-fischeri
#10
Beate I Escher, Andreas Baumer, Kai Bittermann, Luise Henneberger, Maria König, Christin Kühnert, Nils Klüver
The Microtox assay, a bioluminescence inhibition assay with the marine bacterium Aliivibrio fischeri, is one of the most popular bioassays for assessing the cytotoxicity of organic chemicals, mixtures and environmental samples. Most environmental chemicals act as baseline toxicants in this short-term screening assay, which is typically run with only 30 min of exposure duration. Numerous Quantitative Structure-Activity Relationships (QSARs) exist for the Microtox assay for nonpolar and polar narcosis. However, typical water pollutants, which have highly diverse structures covering a wide range of hydrophobicity and speciation from neutral to anionic and cationic, are often outside the applicability domain of these QSARs...
February 15, 2017: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/28196675/occurrence-of-brominated-disinfection-byproducts-in-the-air-and-water-of-chlorinated-seawater-swimming-pools
#11
Tarek Manasfi, Brice Temime-Roussel, Bruno Coulomb, Laurent Vassalo, Jean-Luc Boudenne
An undesirable consequence of disinfection is the formation of chemical contaminants known as disinfection byproducts (DBPs). Chronic exposure to DBPs has been linked to adverse health effects. The occurrence of DBPs in chlorinated pools filled with seawater (such as thalassotherapy pools and pools in spas) has received little attention so far. The present study evaluated the speciation and levels of disinfection byproducts in indoor swimming pools filled with seawater and treated with chlorine. Water and air samples were collected from three indoor swimming pools located in Southern France...
February 5, 2017: International Journal of Hygiene and Environmental Health
https://www.readbyqxmd.com/read/28187746/slow-lung-clearance-and-limited-translocation-of-four-sizes-of-inhaled-iridium-nanoparticles
#12
Alison Buckley, James Warren, Alan Hodgson, Tim Marczylo, Konstantin Ignatyev, Chang Guo, Rachel Smith
BACKGROUND: Concerns have been expressed that inhaled nanoparticles may behave differently to larger particles in terms of lung clearance and translocation, with potential implications for their toxicity. Studies undertaken to investigate this have typically involved limited post-exposure periods. There is a shortage of information on longer-term clearance and translocation patterns and their dependence on particle size, which this study aimed to address. METHODS: Rats were exposed (<3 h) nose-only to aerosols of spark-generated radioactive iridium-192 nanoparticles of four sizes: 10 nm, 15 nm, 35 nm and 75 nm (count median diameter) (aerosol mass concentrations 17, 140, 430, and 690 μg/m(3), respectively)...
February 10, 2017: Particle and Fibre Toxicology
https://www.readbyqxmd.com/read/28168160/insights-into-biochemical-alteration-in-cancer-associated-fibroblasts-by-using-novel-correlative-spectroscopy
#13
Saroj Kumar, Xia Liu, Ferenc Borondics, Qunfeng Xiao, Renfei Feng, Erik Goormaghtigh, Fredrik Nikolajeff
The microenvironment of a tumor changes chemically and morphologically during cancer progression. Cancer-stimulated fibroblasts promote tumor growth, however, the mechanism of the transition to a cancer-stimulated fibroblast remains elusive. Here, the multi-modal spectroscopic methods Fourier transform infrared imaging (FTIRI), X-ray absorption spectroscopy (XAS) and X-ray fluorescence imaging (XFI) are used to characterize molecular and atomic alterations that occur in cancer-stimulated fibroblasts. In addition to chemical changes in lipids (olefinic and acyl chain) and protein aggregation observed with FTIRI, a new infrared biomarker for oxidative stress in stimulated fibroblasts is reported...
February 2017: ChemistryOpen
https://www.readbyqxmd.com/read/28161585/heavy-metal-concentrations-and-speciation-in-riverine-sediments-and-the-risks-posed-in-three-urban-belts-in-the-haihe-basin
#14
Chao Zhang, Baoqing Shan, Wenzhong Tang, Lixin Dong, Wenqiang Zhang, Yuansheng Pei
Heavy metal (Cr, Cu, Ni, Pb, and Zn) pollution and the risks posed by the heavy metals in riverine sediments in a mountainous urban-belt area (MB), a mountain-plain urban-belt area (MPB), and a plain urban-belt area (PB) in the Haihe Basin, China, were assessed. The enrichment factors indicated that the sediments were more polluted with Cu and Zn than with the other metals, especially in the MPB. The sediments in the MPB were strongly affected by Cu and Zn inputs from anthropogenic sources. The risk assessment codes and individual contamination factors showed that Zn was mobile and posed ecological risks, the exchangeable fractions being 21...
February 2, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28159306/source-apportionment-of-pm2-5-in-baton-rouge-louisiana-during-2009-2014
#15
Fenglin Han, Sri Harsha Kota, Yungang Wang, Hongliang Zhang
Particulate matter with aerodynamic diameter <2.5μm (PM2.5) chemical composition data from the Speciation Trends Network (STN) site located in Baton Rouge, Louisiana were analyzed using the receptor Positive Matrix Factorization (PMF) model version 5.0. The PM2.5 samples were collected every third day from January 2009 to December 2014. Seven sources were identified, including secondary sulfate, secondary nitrate, industrial emissions, traffic, crustal dust, road dust and sea salt. The contributions of these seven sources to PM2...
January 31, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28159303/transcriptional-responses-of-zebrafish-to-complex-metal-mixtures-in-laboratory-studies-overestimates-the-responses-observed-with-environmental-water
#16
Ajay Pradhan, Per Ivarsson, Daniel Ragnvaldsson, Håkan Berg, Jana Jass, Per-Erik Olsson
Metals released into the environment continue to be of concern for human health. However, risk assessment of metal exposure is often based on total metal levels and usually does not take bioavailability data, metal speciation or matrix effects into consideration. The continued development of biological endpoint analyses are therefore of high importance for improved eco-toxicological risk analyses. While there is an on-going debate concerning synergistic or additive effects of low-level mixed exposures there is little environmental data confirming the observations obtained from laboratory experiments...
January 31, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28139322/the-local-impact-of-a-coal-fired-power-plant-on-inorganic-mercury-and-methyl-mercury-distribution-in-rice-oryza-sativa-l
#17
Xiaohang Xu, Bo Meng, Chao Zhang, Xinbin Feng, Chunhao Gu, Jianyang Guo, Kevin Bishop, Zhidong Xu, Sensen Zhang, Guangle Qiu
Emission from coal-fired power plants is one of the major anthropogenic sources of mercury (Hg) in the environment, because emitted Hg can be quickly deposited nearby the source, attention is paid to the effects of coal-burning facilities on levels of toxic methyl-mercury (MeHg) in biota near such sources. Since rice is an agricultural crop that can bio-accumulate MeHg, the potential effects of a large Hg-emitting coal-fired power plant in Hunan Province, China on both inorganic Hg (Hg(II)) and MeHg distributions in rice was investigated...
January 27, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28131040/antimony-leaching-and-chemical-species-analyses-in-an-industrial-solid-waste-surface-and-bulk-speciation-using-tof-sims-and-xanes
#18
P Kappen, G Ferrando-Miguel, S M Reichman, L Innes, E Welter, P J Pigram
The surface chemistry and bulk chemical speciation of solid industrial wastes containing 8wt-% antimony (Sb) were investigated using synchrotron X-ray Absorption Near Edge Structure (XANES) and Time-of-Flight Ion Secondary Mass Spectrometry (ToF-SIMS). Leaching experiments were conducted in order to better understand the behavior of Sb in waste streams and to inform regulatory management of antimony-containing wastes. The experiments also demonstrate how a combination of XANES and ToF-SIMS adds value to the field of waste investigations...
January 15, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28121460/polychlorinated-biphenyls-in-alfalfa-accumulation-sorption-and-speciation-in-different-plant-parts
#19
Ying Teng, Xianghui Sun, Lingjia Zhu, Peter Christie, Yongming Luo
The accumulation, chemical speciation and distribution of polychlorinated biphenyls (PCBs) were investigated in various parts of alfalfa. Moreover, the adsorption characteristics for PCB 28 by alfalfa and the influencing factors of the adsorption characteristics were studied. There were different degrees of PCB accumulation in alfalfa roots, root nodules and shoots. The decreasing order of the accumulation of PCBs in plant tissues was root nodules > roots > shoots, and the decreasing order of the total PCB contents was roots > shoots > root nodules, indicating that the roots were the main sink for PCB accumulation...
January 25, 2017: International Journal of Phytoremediation
https://www.readbyqxmd.com/read/28117743/global-sources-and-pathways-of-mercury-in-the-context-of-human-health
#20
REVIEW
Kyrre Sundseth, Jozef M Pacyna, Elisabeth G Pacyna, Nicola Pirrone, Rebecca J Thorne
This paper reviews information from the existing literature and the EU GMOS (Global Mercury Observation System) project to assess the current scientific knowledge on global mercury releases into the atmosphere, on global atmospheric transport and deposition, and on the linkage between environmental contamination and potential impacts on human health. The review concludes that assessment of global sources and pathways of mercury in the context of human health is important for being able to monitor the effects from implementation of the Minamata Convention targets, although new research is needed on the improvement of emission inventory data, the chemical and physical behaviour of mercury in the atmosphere, the improvement of monitoring network data, predictions of future emissions and speciation, and on the subsequent effects on the environment, human health, as well as the economic costs and benefits of reducing these aspects...
January 22, 2017: International Journal of Environmental Research and Public Health
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