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Chemical speciation

María de Jesús González-Guadarrama, Ma Aurora Armienta-Hernández, André H Rosa
Aiming to determine the relationship between source and complexing capacity, humic substances obtained from three sites (Sorocaba and Itapanhau Brasilian rivers, and Xochimilco Lake in Mexico) were studied. Copper, manganese, zinc and arsenic complexing capacity were determined for the three substances under various pH conditions. Results showed similar complexing capacity for the three elements depending on the chemistry of each one and on the physico-chemical conditions. Speciation diagrams showed that these conditions affect both, the humic substances, and the transition metals and arsenic...
March 14, 2018: Bulletin of Environmental Contamination and Toxicology
Alain Manceau, Jianxu Wang, Mauro Rovezzi, Pieter Glatzel, Xinbin Feng
Plant leaves serve both as a sink for gaseous elemental mercury (Hg) from the atmosphere and a source of toxic mercury to terrestrial ecosystems. Litterfall is the primary deposition pathway of atmospheric Hg to vegetated soils, yet the chemical form of this major Hg input remains elusive. We report the first observation of in vivo formation of mercury sulfur nanoparticles in intact leaves of 22 native plants from six different species across two sampling areas from China. The plants grew naturally in soils from a mercury sulfide mining and retorting region at ambient-air gaseous-Hg concentrations ranging from 131 ± 19 to 636 ± 186 ng m-3 and had foliar Hg concentration between 1...
March 14, 2018: Environmental Science & Technology
Perrine Chaurand, Wei Liu, Daniel Borschneck, Clément Levard, Mélanie Auffan, Emmanuel Paul, Blanche Collin, Isabelle Kieffer, Sophie Lanone, Jérôme Rose, Jeanne Perrin
In this methodological study, we demonstrated the relevance of 3D imaging performed at various scales for the ex vivo detection and location of cerium oxide nanomaterials (CeO2 -NMs) in mouse lung. X-ray micro-computed tomography (micro-CT) with a voxel size from 14 µm to 1 µm (micro-CT) was combined with X-ray nano-computed tomography with a voxel size of 63 nm (nano-CT). An optimized protocol was proposed to facilitate the sample preparation, to minimize the experimental artifacts and to optimize the contrast of soft tissues exposed to metal-based nanomaterials (NMs)...
March 13, 2018: Scientific Reports
Sunhye Kim, Tae-Young Kim, Seung-Muk Yi, Jongbae Heo
The sources of different pollutants contributing to ambient fine particles (PM2.5 ) on Daebu Island, Korea, were estimated. Twenty four hour integrated filter samples were collected from May 21-November 1, 2016, and analyzed for organic carbon, elemental carbon, ions, and trace elements. Positive matrix factorization was conducted on the PM2.5 chemical speciation data from the samples to define the pathways and sources of PM2.5 at the sampling site. A total of 80 samples and 24 chemical species were used to run the model and a total of nine sources were identified: secondary sulfate (29...
March 10, 2018: Journal of Environmental Management
Rajendran Selvakumar, Govindarajan Ramadoss, Mridula P Menon, Karuppuli Rajendran, Palanisami Thavamani, Ravi Naidu, Mallavarapu Megharaj
Uranium contamination of soil has been a major concern with respect to its toxicity, accumulation in the food chain and persistence in the environment. Owing to these problems, remediation of uranium-contaminated soils has been investigated by various techniques. This review focuses on the challenges and complexities associated with the remediation of uranium-contaminated soil at field level. Therefore, laboratory studies have been excluded from this review. Challenges faced during remediation of uranium-contaminated soil using various techniques such as microbial/phyto/chemical/material based strategies have been discussed with suitable examples...
March 7, 2018: Journal of Environmental Radioactivity
Wenjuan Zhang, Yang Wang, Zhufeng Geng, Shanshan Guo, Juqin Cao, Zhe Zhang, Xue Pang, Zhenyang Chen, Shushan Du, Zhiwei Deng
The speciation of a methanolic extract of Zanthoxylum armatum stem bark has enabled the isolation and characterization of 11 known lignans. Among them, five compounds ( 6 , 8 - 11 ) are reported in this plant for the first time. All of the chemical structures were elucidated on the basis of NMR spectral analysis. Additionally, their antifeedant activities against Tribolium castaneum were evaluated scientifically. Among them, asarinin ( 1 ), with an EC50 of 25.64 ppm, exhibited a much stronger antifeedant activity than the positive control, toosendanin (EC50 = 71...
March 9, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Tamas Kiss, Eva A Enyedy, Tamas Jakusch, Orsolya Domotor
Biospeciation of essential and toxic metal ions, metal complexes with biological or medicinal activity are discussed in the paper in order to emphasize the importance of the distribution of metal ions in biological milieu. The exact knowledge of the chemical species present in the different organs/compartments/fluids/cells may provide essential information about the pharmacokinetic properties and the biological effect of the metal ion or the drug candidate metal complex. The transport of essential and toxic metal ions in the blood serum is discussed first, which is followed by the description of biodistribution of several important metal complexes with medicinal interest such as (i) anticancer, (ii) insulin-enhancing and (iii) MRI contrast agents in biological fluids...
March 6, 2018: Current Medicinal Chemistry
Dragana Pavlović, Marija Pavlović, Dragan Čakmak, Olga Kostić, Snežana Jarić, Sanja Sakan, Dragana Đorđević, Miroslava Mitrović, Ivan Gržetić, Pavle Pavlović
The main soil properties, concentrations of selected elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), and the chemical speciation of each element were determined in urban soil samples taken from urban parks in four Serbian cities (Belgrade, Pančevo, Obrenovac, and Smederevo) exposed to different sources of pollution. Pollution indices (PI, PIN ) and factors (MF, ICF, GCF) also were evaluated. The study revealed As and Cd concentrations below the detection limit, whereas the content of Cr, Cu, Fe, Mn, Ni, Pb, and Zn at some sites exceeded the limits established by local regulations, as well as the background values, which may represent an environmental threat...
March 5, 2018: Archives of Environmental Contamination and Toxicology
Ewan Couic, Michel Grimaldi, Vanessa Alphonse, Clarisse Balland-Bolou-Bi, Alexandre Livet, Stéphanie Giusti-Miller, Max Sarrazin, Noureddine Bousserrhine
Several decades of gold mining extraction activities in the Amazonian rainforest have caused deforestation and pollution. While ecological rehabilitation is essential for restoring biodiversity and decreasing erosion on deforested lands, few studies note the behaviour or toxicity of trace elements during the rehabilitation process. Our original study focused on the potential use of microbial activity and Hg speciation and compared them with As, Cu, Zn and Cr speciation in assessing the chemical and biological quality of ecological restoration efforts...
March 5, 2018: Environmental Science. Processes & Impacts
D B Abdala, P A Moore, M Rodrigues, W F Herrera, P S Pavinato
Whereas soil test information on the fertility and chemistry of soils has been important to elaborate safe and sound agricultural practices, micro-scale information can give a whole extra dimension to understand the chemical processes occurring in soils. The objective of this study was to evaluate the effects that the consecutive application of untreated poultry litter, alum-treated litter or ammonium nitrate (NH4 NO3 ) had on P solubility in soils over 20 years. For this, we used soil test data, sequential chemical fractionation (SCF) of P, and P K-edge XANES and μ-fluorescence spectroscopies...
February 28, 2018: Journal of Environmental Management
Jun Meng, Sijie Liang, Mengming Tao, Xingmei Liu, Philip C Brookes, Jianming Xu
Pig manure has been utilized as a good feedstock to produce biochar. However, the pig manure-derived biochar from intensive pig cultivation contains high levels of total and bioavailable heavy metals. In this study, the co-pyrolysis of pig manure with other biomass (e.g. rice straw) at 300-700 °C was investigated to solve the above-mentioned topic. The ammonium acetate (CH3 COONH4 ), Tessier sequential extraction procedure and hydrogen peroxide were adopted to evaluate the bioavailability, chemical speciation, and potential risk of Cu and Zn in the biochars...
February 23, 2018: Chemosphere
Markus T Müller
The Chemistry Cube Game invites students at secondary school level 1 and 2 to explore basic concepts of chemistry in a playful way, either as individuals or in teams. It consists of 15 different cubes, 9 cubes for different acids, their corresponding bases and precursors, and 6 cubes for different reducing and oxidising agents. The cubes can be rotated in those directions indicated. Each 'allowed' vertical or horizontal rotation of 90° stands for a chemical reaction or a physical transition. Two different games and playing modes are presented here: First, redox chemistry is introduced for the formation of salts from elementary metals and non-metals...
February 1, 2018: Chimia
Khaled D Alotaibi, Jeff J Schoenau, Gourango Kar, Derek Peak, Terry Fonstad
Sequential chemical extraction and synchrotron-based XANES spectroscopy techniques were used to identify P species in two ashes before and after addition to a prairie soil. The used ashes were: meat and bone meal ash (MBMA) and dried distillers grains ash (DDGA) plus mineral P fertilizer (MP) for comparison. Soil treated with MP contained higher content of resin-Pi and NaHCO3 -Pi followed by DDGA and MBMA. The MBMA amended soil had the highest (47%) proportion of the soil P contained in recalcitrant HCl extractable fraction, reflecting more Ca-bound P present and being formed in soil after application...
February 26, 2018: Scientific Reports
Holly B C Pearson, Lorna J Dallas, Sean D W Comber, Charlotte B Braungardt, Paul J Worsfold, Awadhesh N Jha
Release of tritium (3 H) in the marine environment is of concern with respect to its potential bioaccumulation and detrimental impact on the biota. Previous studies have investigated the uptake and toxicity of this radionuclide in marine mussels, and the interaction of3 H with dissolved organic ligands and elevated temperature. However, despite the well-established view that toxicity is partly governed by chemical speciation, and that toxic effects of mixture of contaminants are not always additive, there have been no studies linking the prevailing chemistry of exposure waters with observed biological effects and tissue specific accumulation of3 H in combination with other constituents commonly found in natural waters...
February 23, 2018: Journal of Environmental Radioactivity
Steven H Brown, Douglas B Chambers
Two traditional methods are used, often in combination, for assessing the intake and resulting dose from the inhalation of radioactive aerosols. The first calculates the intake based on air sampling programs and assessing and assigning dose using published dose conversion factors. The second approach assigns dose from the results of bioassay programs using measurements of radionuclides in human excreta (ex vivo, sometimes referred to as "in vitro") or via direct measurements of radionuclides in the body (in vivo) in combination with metabolic models...
April 2018: Health Physics
J I Pacold, A B Altman, K B Knight, K S Holliday, M J Kristo, S G Minasian, T Tyliszczak, C H Booth, D K Shuh
Synchrotron radiation spectromicroscopy provides a combination of submicron spatial resolution and chemical sensitivity that is well-suited to analysis of heterogeneous nuclear materials. The chemical and physical characteristics determined by scanning transmission X-ray microscopy (STXM) are complementary to information obtained from standard radiochemical analysis methods. In addition, microscopic quantities of radioactive material can be characterized rapidly by STXM with minimal sample handling and intrusion, especially in the case of particulate materials...
February 26, 2018: Analyst
Yanlong Jia, Tangfu Xiao, Jialong Sun, Fei Yang, Philippe C Baveye
Thallium (Tl) is a toxic trace metal, whose geochemical behavior and biological effects are closely controlled by its chemical speciation in the environment. However, little tends to be known about this speciation of Tl in soil and plant systems that directly affect the safety of food supplies. In this context, the objective of the present study was to elaborate an efficient method to separate and detect Tl(I) and Tl(III) species for soil and plant samples. This method involves the selective adsorption of Tl(I) on microcolumns filled with immobilized oxine, in the presence of DTPA (diethylenetriaminepentaacetic acid), followed by DTPA-enhanced ultrasonic and heating-induced extraction, coupled with ICP-MS detection...
February 21, 2018: Science of the Total Environment
Xianmeng Liang, Jinming Song, Liqin Duan, Huamao Yuan, Xuegang Li, Ning Li, Baoxiao Qu, Qidong Wang
Total contents and chemical speciation of Co, Ni, Cu, Ga, Mo, Cd, In, Sn, Sb, V, W, Tl, Bi and U in size-fractionated (<32, 32-63 and >63μm) core sediments from Jiaozhou Bay were investigated to reveal their responses to anthropogenic activities. Metal contents showed a decreasing trend with increasing grain sizes. However, the loadings of metal fraction on <32, 32-63 and >63μm grain sizes were 16%, 47% and 37%, respectively. Anthropogenic fluxes and enrichment factors of metals in >63μm fraction were closely linked to anthropogenic activities, with an obvious increase in upper 27cm (1998-2015) and a slight decrease in 2009year...
February 2018: Marine Pollution Bulletin
Francisco Pena-Pereira, Lorena Villar-Blanco, Isela Lavilla, Carlos Bendicho
A rapid, simple and affordable method for arsenic speciation analysis is described in this work. The proposed methodology involves in situ arsine generation, transfer of the volatile to the headspace and its reaction with silver nitrate at the detection zone of a paper-based analytical device (PAD). Thus, silver nitrate acts as a recognition element for arsine in the paper-based sensor. The chemical reaction between the recognition element and the analyte derivative results in the formation of a colored product which can be detected by scanning the detection zone and data treatment with an image processing and analysis program...
June 29, 2018: Analytica Chimica Acta
Zhanlan Fan, Vivian C Pun, Xiao-Cui Chen, Qiu Hong, Linwei Tian, Steven Sai-Hang Ho, Shun-Cheng Lee, Lap Ah Tse, Kin-Fai Ho
BACKGROUND: Given the lack of research on the personal exposure to fine particles (PM2.5 ) in Hong Kong, we examined the association between short-term personal exposure to PM2.5 and their constituents and inflammation in exhaled breath in a sample of healthy adult residents. METHOD: Forty-six participants underwent personal PM2.5 monitoring for averagely 6 days to obtain 276 samples. Fractional exhaled nitric oxide (FeNO), a biomarker of inflammation in exhaled breath, was measured at the end of each 24-h personal monitoring...
February 17, 2018: Environmental Research
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