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Chemical speciation

Imad Aharchaou, Jean-Sebastien Py, Sebastien Cambier, Jean-Luc Loizeau, Geert Cornelis, Philippe Rousselle, Eric Battaglia, Davide A L Vignati
Despite the consensus about the importance of chemical speciation in controlling the bioavailability and ecotoxicity of trace elements, detailed speciation studies during laboratory ecotoxicity testing remain scarce, contributing to uncertainty when extrapolating laboratory findings to real field situations in risk assessment. We characterized the speciation and ecotoxicological effects of Cr(III) and Cr(VI) in the ISO medium for algal ecotoxicity testing. Total and dissolved (<0.22 μm) Cr concentrations showed little variability in media spiked with Cr(VI) , while dissolved Cr concentration decreased by as much as 80% over 72 hours in medium amended with Cr(III) ...
November 18, 2017: Environmental Toxicology and Chemistry
Joanna Legat, Magdalena Matczuk, Andrei R Timerbaev, Maciej Jarosz
The cellular uptake of gold nanoparticles (AuNPs) may (or may not) affect their speciation, but information on the chemical forms in which the particles exist in the cell remains obscure. An analytical method based on the use of capillary electrophoresis hyphenated with inductively coupled plasma mass spectrometry (ICP-MS) has been proposed to shed light on the intracellular processing of AuNPs. It was observed that when being introduced into normal cytosol, the conjugates of 10-50 nm AuNPs with albumin evolved in human serum stayed intact...
November 15, 2017: Analytical and Bioanalytical Chemistry
Ashraf M M Essa, Mohamed A Al Abboud, Sayeed I Khatib
Microorganisms can modify the chemical and physical characters of metals leading to an alteration in their speciation, mobility, and toxicity. Aqueous heavy metals solutions (Hg, Cd, Pb, Ag, Cu, and Zn) were treated with the volatile metabolic products (VMPs) of Escherichia coli Z3 for 24 h using aerobic bioreactor. The effect of the metals treated with VMPs in comparison to the untreated metals on the growth of E. coli S1 and Staphylococcus aureus S2 (local isolates) was examined. Moreover, the toxic properties of the treated and untreated metals were monitored using minimum inhibitory concentration assay...
November 15, 2017: Journal of Basic Microbiology
Zuzana Lukáčová-Chomisteková, Eva Culková, Renata Bellová, Danica Melicherčíková, Jaroslav Durdiak, Ernest Beinrohr, Miroslav Rievaj, Peter Tomčík
Very simple and fast electroanalytical method for the detection Sb(III) on chemically unmodified boron-doped diamond electrode (BDDE) has been developed. Voltammetric behavior of antimony was investigated in various acidic supporting electrolytes and the most suitable medium for the determination of Sb(III) on bare BDDE has been 6molL(-1) HClO4 solution. The analytical performance was studied with differential pulse anodic stripping voltammetry (DPASV) with optimized conditions (deposition potential -1V vs...
February 1, 2018: Talanta
Kathy Darragh, Sohini Vanjari, Florian Mann, Maria F Gonzalez-Rojas, Colin R Morrison, Camilo Salazar, Carolina Pardo-Diaz, Richard M Merrill, W Owen McMillan, Stefan Schulz, Chris D Jiggins
Sex-specific pheromones are known to play an important role in butterfly courtship, and may influence both individual reproductive success and reproductive isolation between species. Extensive ecological, behavioural and genetic studies of Heliconius butterflies have made a substantial contribution to our understanding of speciation. Male pheromones, although long suspected to play an important role, have received relatively little attention in this genus. Here, we combine morphological, chemical and behavioural analyses of male pheromones in the Neotropical butterfly Heliconius melpomene...
2017: PeerJ
Binghui Zheng, Shaoyong Lu, Jinan Wu, Xiaochun Guo, Fengchang Wu, Xiangling Li, Qi He, Zhiyou Fu, Libin Xu
According to current study, seven surface sediments and three sediment cores were collected from three typical areas of Tiaoxi River, which were living area, agricultural area, and industrial area. The water quantity into the Lake Taihu from the Tiaoxi River accounted for almost one third of the total water quantity by all rivers into the Lake Taihu. To study geochemical features and pollution history of heavy metals in three typical areas of Tiaoxi River, total content and chemical fractionations of Cu, Pb, Cd, Cr, Mn, Zn, Fe, As, and Hg were analyzed for surface and core sediments using the speciation extraction procedure, proposed by the Commission of the European Communities Bureau of Reference (BCR), together with grain size and organic carbon measurements...
November 12, 2017: Environmental Science and Pollution Research International
Peng Wang, Qi Ying, Hongliang Zhang, Jianlin Hu, Yingchao Lin, Hongjun Mao
A Community Multiscale Air Quality (CMAQ) model with source-oriented lumped SAPRC-11 (S11L) photochemical mechanism and secondary organic aerosol (SOA) module was applied to determine the contributions of anthropogenic and biogenic sources to SOA concentrations in China. A one-year simulation of 2013 using the Multi-resolution Emission Inventory for China (MEIC) shows that summer SOA are generally higher (10-15 μg m(-3)) due to large contributions of biogenic (country average 60%) and industrial sources (17%)...
November 8, 2017: Environmental Pollution
Jin Liu, Jianjun Yang, Barbara J Cade-Menun, Yongfeng Hu, Jumei Li, Chang Peng, Yibing Ma
Soil legacy phosphorus (P) represents a substantial secondary P resource to postpone the global P crisis. To fully utilize this P reserve, the transformation of legacy P speciation in a black soil with and without P fertilization for 27 years was investigated by chemical fractionation, molecular-level bulk (P K-edge X-ray absorption near-edge, XANES; solution (31)P nuclear magnetic resonance) and microprobe (µ-X-ray fluorescence and µ-XANES) spectroscopy. Results from both fractionation and P bulk-XANES concordantly indicated that Ca2-P [Ca(H2PO4)2] acts as a reserve of labile P in response to soils with or without P fertilization...
November 10, 2017: Scientific Reports
Ying Shi, Lei Gan, Xibing Li, Suya He, Cheng Sun, Li Gao
Phosphate rock in Guiyang (Southwest of China) is used for the phosphate production, and hence generating a by-product phosphogypsum (PG). From 2007, part of the PG was used as main raw material for cemented backfill. The main objective of this paper is to investigate the geochemical evolution of metals before and after the PG inclusion into the backfill matrix. A sequential extraction procedure was selected to determine the chemical speciation of metals in phosphate rock, PG, binder and field backfill samples...
November 1, 2017: Chemosphere
Éva G Bajnóczi, Zoltán Németh, György Vankó
Even quite simple chemical systems can involve many components and chemical states, and sometimes it can be very difficult to differentiate them by their hardly separable physical-chemical properties. The Ni(II)-EDTA-CN(-) (EDTA = ethylenediaminetetraacetic acid) ternary system is a good example for this problem where, in spite of its fairly simple components and numerous investigations, several molecular combinations can exist, all of them not having been identified unambiguously yet. In order to achieve a detailed understanding of the reaction steps and chemical equilibria, methods are required in which the structural transitions in the different reaction steps can be followed via element-selective complex spectral feature sets...
November 8, 2017: Inorganic Chemistry
Antonio J Martín, Sharon Mitchell, Olivier Scholder, René Verel, Roland Hauert, Laetitia Bernard, Christopher Jensen, Meinhard Schwefer, Javier Pérez-Ramírez
An improved understanding of the nature and distribution of boron and cesium species in BCsX zeolites is prerequisite to guide future developments in the environmentally attractive yet challenging production of styrene via the side-chain alkylation of toluene with methanol. Here, standard characterization and catalytic tests are complemented by integrated visualization through time-of-flight secondary ion mass spectrometry and energy-dispersive X-ray spectroscopy and detailed assessment by 133Cs and 11B nuclear magnetic resonance spectroscopy, to correlate the properties and performance during the successive ion exchange and impregnation steps in the preparation of both powders and millimeter-sized granules...
November 7, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Yang-Guang Gu
Intertidal surface sediments collected from Zhelin Bay, the largest mariculture base of eastern Guangdong Province of China, were analyzed for total metal concentrations and chemical speciation. Average total metal concentrations (mg/kg) were 0.063 (Cd), 35.69 (Pb), 23.07 (Cr), 7.50 (Ni), 7.95 (Cu), 74.95 (Zn), and 751.32 (Mn). Concentrations of Cd, Cu, Zn, and Mn were significantly higher than the corresponding background values of Zhelin Bay. All studied metals were dominated by residual fractions, whereas the second relatively higher average portions of Cd (24...
October 26, 2017: Marine Pollution Bulletin
Murugaeson R Kumar, Patrick J Farmer
Small oxoacids of sulfur (SOS) are elusive molecules like sulfenic acid, HSOH, and sulfinic acid, HS(O)OH, generated during the oxidation of hydrogen sulfide, H2S, in aqueous solution. Unlike their alkyl homologs, there is a little data on their generation and speciation during H2S oxidation. These SOS may exhibit both nucleophilic and electrophilic reactivity, which we attribute to interconversion between S(II) and S(IV) tautomers. We find that SOS may be trapped in situ by derivatization with nucleophilic and electrophilic trapping agents and then characterized by high resolution LC MS...
October 16, 2017: Redox Biology
Yuan-Cheng Li, Xiao-Bo Min, Yong Ke, Li-Yuan Chai, Mei-Qing Shi, Chong-Jian Tang, Qing-Wei Wang, Yan-Jie Liang, Jie Lei, De-Gang Liu
A new method in which Pb/Zn smelter waste containing arsenic and heavy metals (arsenic sludge), red mud and lime are utilized to prepare red mud-based cementitious material (RCM) is proposed in this study. XRD, SEM, FTIR and unconfined compressive strength (UCS) tests were employed to assess the physicochemical properties of RCM. In addition, ettringite and iron oxide-containing ettringite were used to study the hydration mechanism of RCM. The results show that the UCS of the RCM (red mud+arsenic sludge+lime) was higher than that of the binder (red mud+arsenic sludge)...
October 23, 2017: Journal of Hazardous Materials
Tan Wenyi, Fan Wenhui, Li Hongyi, Zhang Zixin, Zhu Yunkun
CO2 sequestration by flue gas desulfurization gypsum (FGDG) has become a promising FGDG disposal technology due to simultaneous CO2 emission reduction and FGDG conversion into calcium carbonate. In this paper, another merit of the novel technology, i.e., the removal of toxic elements (e.g., Hg and As) in FGDG, will be addressed for the first time. In three different aqueous ammonia (or amines) media, removal efficiencies of Hg and As in FGDG samples were evaluated during CO2 sequestration. Higher than 90% and 20% removal efficiencies, respectively, for Hg and As are achieved at 40°C in aqueous ammonia media, but they decrease at elevated temperatures...
October 1, 2017: Waste Management & Research
Felix Neumaier, Serdar Alpdogan, Jürgen Hescheler, Toni Schneider
Recent recognition that mobile pools of Zn(2+) and Cu(2+) are involved in the regulation of neuronal, endocrine and other cells has stimulated the development of tools to visualize and quantify the level of free trace metal ions. Most of the methods used to measure or control loosely bound metals require reference media that contain exactly defined free concentrations of the target ions. Despite the central importance of proper metal ion buffering, there is still a lack of international standards and beginners in the field may have difficulties finding a coherent description of how to prepare trace metal ion buffers, especially when experiments are to be performed in multi-metal systems...
October 24, 2017: Acta Physiologica
Hongli Wang, Zhiyuan Xiang, Lina Wang, Shengao Jing, Shengrong Lou, Shikang Tao, Jing Liu, Mingzhou Yu, Li Li, Li Lin, Ying Chen, Alfred Wiedensohler, Changhong Chen
Cooking emission is one of sources for ambient volatile organic compounds (VOCs), which is deleterious to air quality, climate and human health. These emissions are especially of great interest in large cities of East and Southeast Asia. We conducted a case study in which VOC emissions from kitchen extraction stacks have been sampled in total 57 times in the Megacity Shanghai. To obtain representative data, we sampled VOC emissions from kitchens, including restaurants of seven common cuisine types, canteens, and family kitchens...
October 17, 2017: Science of the Total Environment
D Pozebon, G L Scheffler, V L Dressler
Although exogenous contamination and unreliable reference values have limited the utility of scalp hair as a biomarker of chemical elements exposure, its use in toxicological, clinical, environmental and forensic investigations is growing and becoming more extensive. Therefore, hair elemental analysis is reviewed in the current manuscript which spans articles published in the last 10 years. It starts with a general discussion of history, morphology and possible techniques for elemental analysis, where inductively coupled plasma-mass spectrometry (ICP-MS) is clearly highlighted since this technique is leading quantitative ultra-trace elemental analysis...
November 1, 2017: Analytica Chimica Acta
James H Lindsay, Alan J Kennedy, Jennifer M Seiter-Moser, Anthony J Bednar, Robert E Boyd, David R Johnson, Paul Allison, Ryan V Tappero
This investigation builds on previous studies on military relevant tungsten (W) to more thoroughly explore environmental pathways, bioaccumulation kinetics during direct soil exposure versus trophic transfer and elucidate its relative accumulation and speciation in different snail organs. The modeled steady state concentration and bioaccumulation factor (BAF) of W from soil into cabbage were 302 mg/kg and 0.55, respectively. Steady state concentrations (34 mg/kg) and BAF values (0.05) obtained for the snail directly exposed to contaminated soil were lower than trophic transfer by consumption of W-contaminated cabbage (tissue concentration of 86 mg/kg; BAF of 0...
October 20, 2017: Environmental Science & Technology
Dong-Hai Yuan, Jiang-Wei He, Chong-Wei Li, Xu-Jing Guo, Ying Xiong, Chen-Ling Yan
The water-purification performance of grassy swales for treating stormwater road runoff was evaluated using a simulated experimental device in two different seasons. The results showed that the removal rates for total suspended solids (TSS), chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) reached 89.90%, 56.71%, 32.37%, and 19.67%, respectively, in summer, and 34.09%, 7.75%, 56.71%, and 13.33%, respectively, in winter, suggesting that grassy swales showed higher water purification performance in summer than in winter...
October 20, 2017: Environmental Technology
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