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Chemical speciation

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https://www.readbyqxmd.com/read/28102706/co-effect-of-phosphorus-and-cadmium-interaction-on-fraction-distribution-and-accumulation-of-phosphorus-in-mangrove-sediment-system
#1
Jingna Du, Junyi Yu
Mangrove (Kandelia obovata (S. L.)) seedlings were cultivated in rhizoboxes under different rates of phosphorus (P) and cadmium (Cd) level. The speciation distributions of P both in the rhizosphere and non-rhizosphere sediments were examined using sequential extraction procedures. P contents in different Kandelia obovata (S.L.) tissues were also determined. Results showed that considerable differences existed in P speciation distribution between rhizosphere and bulk sediments. A higher proportion of iron-bound phosphate (Fe-P) was found in the rhizosphere sediments, while a relatively higher concentration of exchangeable phosphate (Ex-P) and Al-bound phosphate (Al-P) was found in the bulk sediments...
January 19, 2017: International Journal of Phytoremediation
https://www.readbyqxmd.com/read/28089841/the-birth-of-aposematism-high-phenotypic-divergence-and-low-genetic-diversity-in-a-young-clade-of-poison-frogs
#2
Rebecca Dent Tarvin, Emily A Powell, Juan C Santos, Santiago R Ron, David C Cannatella
Rapid radiation coupled with low genetic divergence often hinders species delimitation and phylogeny estimation even if putative species are phenotypically distinct. Some aposematic species, such as poison frogs (Dendrobatidae), have high levels of intraspecific color polymorphism, which can lead to overestimation of species when phenotypic divergence primarily guides species delimitation. We explored this possibility in the youngest origin of aposematism (3-7 MYA) in poison frogs, Epipedobates, by comparing genetic divergence with color and acoustic divergence...
January 13, 2017: Molecular Phylogenetics and Evolution
https://www.readbyqxmd.com/read/28089210/pm10-and-pm2-5-chemical-source-profiles-with-optical-attenuation-and-health-risk-indicators-of-paved-and-unpaved-road-dust-in-bhopal-india
#3
Shilpi Samiksha, Ramya Sunder Raman, Jayant Nirmalkar, Samresh Kumar, Rohit Sirvaiya
Size classified (PM10 and PM2.5) paved and unpaved road dust chemical source profiles, optical attenuation and potential health risk from exposure to these sources are reported in this study. A total of 45 samples from 9 paved road and 6 unpaved road sites located in and around Bhopal were re-suspended in the laboratory, collected onto filter substrates and subjected to a variety of chemical analyses. In general, road dust was enriched (compared to upper continental crustal abundance) in anthropogenic pollutants including Sb, Cu, Zn, Co, and Pb...
January 11, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28068580/bioavailability-and-health-risk-of-some-potentially-toxic-elements-cd-cu-pb-and-zn-in-street-dust-of-asansol-india
#4
Manash Gope, Reginald Ebhin Masto, Joshy George, Raza Rafiqul Hoque, Srinivasan Balachandran
Street dust samples were collected from five different types of land use patterns (busy traffic zone, urban residential area, national highways, industrial area and sensitive area) in a medium sized industrial city Asansol, India. The samples were fractionated into ≤53µm and analyzed for potential toxic elements (PTEs) viz. Zn, Cd, Pb and Cu. The mean total concentration of Zn, Cd, Pb and Cu in the urban street dust samples were 192, 0.75, 110 and 132mgkg(-1) respectively. Chemical speciation was performed for PTEs to evaluate the bio-available fractions...
January 6, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28068569/quantification-of-ph-dependent-speciation-of-organic-compounds-with-spectroscopy-and-chemometrics
#5
Thomas Ritschel, Kai Uwe Totsche
Fluorescence and UV/Vis spectra of aqueous solutions with numerous organic compounds are a superposition of single spectra of the chemical species present. Thus, an isolation of individual spectra with chemometrics is required for their quantification. We investigated UV/Vis spectra and fluorescence excitation-emission matrices of vanillic acid, salicylic acid, phenoxyacetic acid and phthalic acid with positive matrix factorization (PMF) and non-negativity constrained parallel factor analysis (PARAFAC) in combination with the law of mass action...
December 30, 2016: Chemosphere
https://www.readbyqxmd.com/read/28064134/cumulative-effects-of-bamboo-sawdust-addition-on-pyrolysis-of-sewage-sludge-biochar-properties-and-environmental-risk-from-metals
#6
Junwei Jin, Minyan Wang, Yucheng Cao, Shengchun Wu, Peng Liang, Yanan Li, Jianyun Zhang, Jin Zhang, Ming Hung Wong, Shengdao Shan, Peter Christie
A novel type of biochar was produced by mixing bamboo sawdust with sewage sludge (1:1, w/w) via a co-pyrolysis process at 400-600°C. Changes in physico-chemical properties and the intrinsic speciation of metals were investigated before and after pyrolysis. Co-pyrolysis resulted in a lower biochar yield but a higher C content in the end product compared with use of sludge alone as the raw material. FT-IR analysis indicates that phosphine derivatives containing PH bonds were formed in the co-pyrolyzed biochars...
December 30, 2016: Bioresource Technology
https://www.readbyqxmd.com/read/28063315/chemical-modeling-of-groundwater-in-the-banat-plain-southwestern-romania-with-elevated-as-content-and-co-occurring-species-by-combining-diagrams-and-unsupervised-multivariate-statistical-approaches
#7
Sinziana Butaciu, Marin Senila, Costel Sarbu, Michaela Ponta, Claudiu Tanaselia, Oana Cadar, Marius Roman, Emil Radu, Mihaela Sima, Tiberiu Frentiu
The study proposes a combined model based on diagrams (Gibbs, Piper, Stuyfzand Hydrogeochemical Classification System) and unsupervised statistical approaches (Cluster Analysis, Principal Component Analysis, Fuzzy Principal Component Analysis, Fuzzy Hierarchical Cross-Clustering) to describe natural enrichment of inorganic arsenic and co-occurring species in groundwater in the Banat Plain, southwestern Romania. Speciation of inorganic As (arsenite, arsenate), ion concentrations (Na(+), K(+), Ca(2+), Mg(2+), HCO3(-), Cl(-), F(-), SO4(2-), PO4(3-), NO3(-)), pH, redox potential, conductivity and total dissolved substances were performed...
December 29, 2016: Chemosphere
https://www.readbyqxmd.com/read/28057469/importance-of-sulfide-interaction-with-iron-as-regulator-of-the-microbial-community-in-biogas-reactors-and-its-effect-on-methanogenesis-volatile-fatty-acids-turnover-and-syntrophic-long-chain-fatty-acids-degradation
#8
Sepehr Shakeri Yekta, Ryan M Ziels, Annika Björn, Ulf Skyllberg, Jörgen Ejlertsson, Anna Karlsson, Matilda Svedlund, Magnus Willén, Bo H Svensson
The inhibitory effects of sulfide on microbial processes during anaerobic digestion have been widely addressed. However, other effects of sulfide are less explored, given that sulfide is a potential sulfur source for microorganisms and its high reactivity triggers a suit of abiotic reactions. We demonstrated that sulfide interaction with Fe regulates the dynamics and activities of microbial community during anaerobic digestion. This was manifested by the S:Fe molar ratio, whose increase adversely influenced the acetoclastic methanogens, Methanosaeta, and turnover of acetate...
January 2, 2017: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/28057398/selenium-speciation-profiles-in-biofortified-sangiovese-wine
#9
Maria Chiara Fontanella, Roberto D'Amato, Luca Regni, Primo Proietti, Gian Maria Beone, Daniela Businelli
Biofortification is an agronomic-based strategy, utilized by farmers, to produce selenium (Se)-enriched food products that may help reduce dietary deficiencies of Se occurring throughout susceptible regions of the world. The foliar exposure route application ensures a high efficiency of Se assimilation by the plant since it does not depend on root-to-shoot translocation. In this study we treated grapevines of Sangiovese variety in the pre-flowering period with sodium selenate (100mg Se L(-1)). Se content was measured in leaves, fruit at harvest time and in wine respectively in treated and not treated samples with ICP-MS...
December 19, 2016: Journal of Trace Elements in Medicine and Biology
https://www.readbyqxmd.com/read/28035726/speciation-of-uranium-mandelic-acid-complexes-using-electrospray-ionization-mass-spectrometry-and-density-functional-theory
#10
Pranaw Kumar, P G Jaison, V M Telmore, Biswajit Sadhu, Mahesh Sundararajan
RATIONALE: Mandelic acid is a complexing agent employed for the liquid chromatographic separation of actinides. However, the types of species and the structural details of the uranyl-mandelate complexes are still unknown. Understanding the nature of these complex species would provide better insight into the mechanism of their separation in liquid chromatography. METHOD: Formation of different species of the uranyl ion (UO2 ) with mandelic acid was studied using electrospray ionization mass spectrometry (ESI-MS) with a quadrupole-time of flight analyzer...
December 30, 2016: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28033517/mechanisms-of-tripolyphosphate-adsorption-and-hydrolysis-on-goethite
#11
Jordan G Hamilton, David Hilger, Derek Peak
Linear tripolyphosphates (TPP) are used extensively in liquid fertilizers though little is known about their chemical fate after sorption on mineral surfaces. The initial rapid adsorption of TPP to metal oxide surfaces has been observed, but it is not known whether this adsorption will catalyze or inhibit TPP hydrolysis. To determine the effects of adsorption upon TPP hydrolysis, batch reactors were set up with two surface loadings of TPP adsorbed on goethite (α-FeOOH) for up to 3months at pH 4.5, 6.5 and 8...
December 19, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28018335/metabolic-conservation-and-diversification-of-metarhizium-species-correlate-with-fungal-host-specificity
#12
Yong-Jiang Xu, Feifei Luo, Bing Li, Yanfang Shang, Chengshu Wang
The ascomycete genus Metarhizium contains several species of insect pathogenic fungi ranging from specialists with narrow host ranges to generalists that can infect diverse invertebrates. Genetic and metabolic conservations and diversifications of Metarhizium species are not well understood. In this study, using the genome information of seven Metarhizium species, we performed a comparative analysis of gene clusters involved in secondary metabolisms (SMs) in these species. The results revealed that the generalist species contain more SM gene clusters than the specialists, and that both conserved and divergent evolutions may have occurred in SM genes during fungal speciation...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28011427/heavy-metals-in-sludge-during-anaerobic-sanitary-landfill-speciation-transformation-and-phytotoxicity
#13
Kai Yang, Ying Zhu, Ranran Shan, Yanqiu Shao, Chao Tian
Sanitary landfill persists as a predominant sludge disposal method in particular in China. In this study, successive subsurface sludge samples (0.3 m deep) were collected from a bioreactor landfill unit where an anaerobic process took place during a 500 d period. The sludge samples were analyzed for total concentrations of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) and their species distributions, together with selected sludge chemical properties. In addition, the sludge samples were subjected to phytotoxicity testing...
December 20, 2016: Journal of Environmental Management
https://www.readbyqxmd.com/read/28011112/the-artificial-and-natural-isotopes-distribution-in-sedge-carex-l-biomass-from-the-yenisei-river-flood-plain-adaptation-of-the-sequential-elution-technique
#14
Marya Kropacheva, Mikhail Melgunov, Irina Makarova
The study of migration pathways of artificial isotopes in the flood-plain biogeocoenoses, impacted by the nuclear fuel cycle plants, requires determination of isotope speciations in the biomass of higher terrestrial plants. The optimal method for their determination is the sequential elution technique (SET). The technique was originally developed to study atmospheric pollution by metals and has been applied to lichens, terrestrial and aquatic bryophytes. Due to morphological and physiological differences, it was necessary to adapt SET for new objects: coastal macrophytes growing on the banks of the Yenisei flood-plain islands in the near impact zone of Krasnoyarsk Mining and Chemical Combine (KMCC)...
February 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28009168/uncertainty-assessment-of-gaseous-oxidized-mercury-measurements-collected-by-atmospheric-mercury-network
#15
Irene Cheng, Leiming Zhang
Gaseous oxidized mercury (GOM) measurement uncertainties undoubtedly impact the understanding of mercury biogeochemical cycling; however, there is a lack of consensus on the uncertainty magnitude. The numerical method presented in this study provides an alternative means of estimating the uncertainties of previous GOM measurements. Weekly GOM in ambient air was predicted from measured weekly mercury wet deposition using a scavenging ratio approach, and compared against field measurements of 2-4 hly GOM to estimate the measurement biases of the Tekran speciation instruments at 13 Atmospheric Mercury Network (AMNet) sites...
December 23, 2016: Environmental Science & Technology
https://www.readbyqxmd.com/read/28002353/ambient-pm2-5-aluminum-and-elemental-carbon-and-placental-abruption-morbidity
#16
Boubakari Ibrahimou, Ahmed N Albatineh, Hamisu M Salihu, Janvier Gasana
PURPOSE: The aim of this study was to assess relationship between exposure to particulate matter (PM) chemicals during pregnancy and the odd of having placental abruption. METHODS: The 2004 to 2007 Florida linked birth certificate records and the Environmental Protection Agency PM speciation data were used. We were interested in placental abruption. We computed adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs). RESULTS: The odds for placental abruption were increased per interquartile range (IQR) increase in aluminum during the first trimester (OR = 1...
December 20, 2016: Journal of Occupational and Environmental Medicine
https://www.readbyqxmd.com/read/27999946/biokinetic-measurements-and-modelling-of-urinary-excretion-of-cerium-citrate-in-humans
#17
Vera Höllriegl, Wei Bo Li, Bernhard Michalke
Tracer kinetics in healthy human volunteers was studied applying stable isotopes of cerium citrate to obtain biokinetic human data for the urinary excretion of cerium. These data were then used to compare and validate the biokinetic model for lanthanides (cerium) proposed by Taylor and Leggett (Radiat Prot Dosim 105:193-198, 2003), which is substantially improved and more realistic than the biokinetic model currently recommended by the International Commission on Radiological Protection (ICRP Publication 67, 1993); both models are primarily based on animal data...
December 20, 2016: Radiation and Environmental Biophysics
https://www.readbyqxmd.com/read/27998782/improvement-of-wastewater-sludge-dewatering-performance-using-titanium-salt-coagulants-tscs-in-combination-with-magnetic-nano-particles-significance-of-titanium-speciation
#18
Weijun Zhang, Zhan Chen, Bingdi Cao, Youjing Du, Caixia Wang, Dongsheng Wang, Teng Ma, Hua Xia
In this study, the effects of chemical conditioning using titanium salt coagulants (TSCs) of different hydrolysis speciation in combination with magnetic nano-particles on dewatering performance of waste activated sludge were evaluated by means of specific resistance to filtration (SRF) and capillary suction time (CST). The morphological and extracellular polymeric substances (EPS) properties under chemical conditioning were investigated in detail to understand the reaction mechanisms involved. The results showed that the TSC with basicity of 0...
December 10, 2016: Water Research
https://www.readbyqxmd.com/read/27993064/effects-of-cellular-sorption-on-mercury-bioavailability-and-methylmercury-production-by-desulfovibrio-desulfuricans-nd132
#19
Yu-Rong Liu, Xia Lu, Linduo Zhao, Jing An, Ji-Zheng He, Eric M Pierce, Alexander Johs, Baohua Gu
Microbial conversion of inorganic mercury (IHg) to methylmercury (MeHg) is a significant environmental concern because of the bioaccumulation and biomagnification of toxic MeHg in the food web. Laboratory incubation studies have shown that, despite the presence of large quantities of IHg in cell cultures, MeHg biosynthesis often reaches a plateau or a maximum within hours or a day by an as yet unexplained mechanism. Here we report that mercuric Hg(II) can be taken up rapidly by cells of Desulfovibrio desulfuricans ND132, but a large fraction of the Hg(II) is unavailable for methylation because of strong cellular sorption...
December 20, 2016: Environmental Science & Technology
https://www.readbyqxmd.com/read/27983824/equilibria-and-speciation-of-chloramines-bromamines-and-bromochloramines-in-water
#20
Daniela Trogolo, J Samuel Arey
The stabilities and speciation of the halamines in water are difficult to characterize experimentally. We provide theoretical estimates of aqueous standard free energies of formation for inorganic chloramines, bromamines, and bromochloramines, based on high-accuracy theoretical standard free energies of formation in gas phase combined with quantum chemical estimates of Henry's law constant. Based on comparisons between several theoretical and experimental datasets, we assign an error of 1.1-1.2 log unit for equilibrium constants of several reactions leading to halamines in water...
January 3, 2017: Environmental Science & Technology
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