Arsenate
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... CONTENTS -- ENVIRONMENTAL HEALTH CRITERIA FOR ARSENIC AND ARSENIC COMPOUNDS -- PREAMBLE xiii -- ABBREVIATIONS ... ... SUMMARY 1 -- 1.1 Properties and analytical procedures 1 -- 1.2 Sources and occurrence of arsenic in the ... ... and Arsenic Compounds -- 2.13 Hyphenated techniques 24 -- 3. ... ... exposure 164 -- 6.3.1 Arsenic in hair and nails 164 -- 6.3.2 Blood arsenic 166 -- 6.3.3 Arsenic and ... ... 212 vii -- EHC 224: Arsenic and Arsenic Compounds -- 7.1.9.3 Induction of proteins 212 -- 7.1.10 Potential ...
Environmental health criteria, ISSN 0250-863X 224
2nd ed. xxvii, 521 s. : tab. ; 22 cm
- MeSH
- arsen škodlivé účinky MeSH
- arsenikové přípravky škodlivé účinky MeSH
- vystavení vlivu životního prostředí MeSH
- Konspekt
- Veřejné zdraví a hygiena
- NLK Obory
- veřejné zdravotnictví
- environmentální vědy
- toxikologie
- environmentální vědy
- environmentální vědy
- toxikologie
- NLK Publikační typ
- publikace WHO
An arsenic (ars) four-gene operon, containing genes encoding a putative membrane permease (ArsP), a transcriptional repressor (ArsR), an arsenate reductase (ArsC) and an arsenical-resistance membrane transporter (Acr3) was first identified in urease-positive thermophilic Campylobacter (UPTC) isolate, CF89-12. UPTC CF89-12 and some other Campylobacter lari isolates contained their ars four-genes, similarly, differing from that in the reference C. lari RM2100 strain. Two putative promoters and a putative terminator were identified for the operon in UPTC CF89-12. In vivo transcription of the operon was confirmed in the UPTC cells. PCR experiments using two primer pairs designed in silico to amplify two arsR and arsC-acr3 segments, respectively, generated two amplicons, approximately 200 and 350 base pairs, with all 31 of 31 and 19 of 31 C. lari isolates (n = 17 for UPTC; n = 14 for UN C. lari), respectively. An inverted repeat forming a dyad structure, a potential binding site for a transcriptional repressor, was identified in the promoter region. Within the deduced 61 amino acids sequence of the putative arsR open reading frame from the UPTC CF89-12, a metal binding box and a DNA-binding helix-turn-helix motif were identified. The UPTC CF89-12 and some other UPTC isolates isolated from natural environment were resistant to arsenate.
- MeSH
- arsen * MeSH
- arsenátreduktasy genetika MeSH
- bakteriální geny * MeSH
- bakteriální RNA genetika MeSH
- Campylobacter lari genetika izolace a purifikace MeSH
- DNA bakterií genetika MeSH
- DNA primery MeSH
- genetické lokusy MeSH
- konformace nukleové kyseliny MeSH
- molekulární sekvence - údaje MeSH
- motiv helix-turn-helix genetika MeSH
- operon genetika MeSH
- otevřené čtecí rámce MeSH
- polymerázová řetězová reakce s reverzní transkripcí MeSH
- sekvence aminokyselin MeSH
- sekvenční analýza DNA MeSH
- sekvenční seřazení MeSH
- ureasa genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We report the first example of arsenite and arsenate removal from water by incorporation of arsenic into the structure of nanocrystalline iron(III) oxide. Specifically, we show the capability to trap arsenic into the crystal structure of γ-Fe2O3 nanoparticles that are in situ formed during treatment of arsenic-bearing water with ferrate(VI). In water, decomposition of potassium ferrate(VI) yields nanoparticles having core-shell nanoarchitecture with a γ-Fe2O3 core and a γ-FeOOH shell. High-resolution X-ray photoelectron spectroscopy and in-field (57)Fe Mössbauer spectroscopy give unambiguous evidence that a significant portion of arsenic is embedded in the tetrahedral sites of the γ-Fe2O3 spinel structure. Microscopic observations also demonstrate the principal effect of As doping on crystal growth as reflected by considerably reduced average particle size and narrower size distribution of the "in-situ" sample with the embedded arsenic compared to the "ex-situ" sample with arsenic exclusively sorbed on the iron oxide nanoparticle surface. Generally, presented results highlight ferrate(VI) as one of the most promising candidates for advanced technologies of arsenic treatment mainly due to its environmentally friendly character, in situ applicability for treatment of both arsenites and arsenates, and contrary to all known competitive technologies, firmly bound part of arsenic preventing its leaching back to the environment. Moreover, As-containing γ-Fe2O3 nanoparticles are strongly magnetic allowing their separation from the environment by application of an external magnet.
- MeSH
- arsen chemie MeSH
- arseničnany izolace a purifikace MeSH
- arsenitany izolace a purifikace MeSH
- fotoelektronová spektroskopie MeSH
- kinetika MeSH
- koncentrace vodíkových iontů MeSH
- krystalografie rentgenová MeSH
- magnetické nanočástice chemie ultrastruktura MeSH
- spektroskopie Mossbauerova MeSH
- teplota MeSH
- velikost částic MeSH
- železo chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nine low-rank coal samples from three different coal basins (Velenje and Trbovlje basins, Slovenia, and Sokolov basin, Czech Republic) were analyzed for their elemental composition and the presence of arsenic compounds. Total arsenic concentrations in the samples were 1.59-5.77 microg g(-1) with one exception, 142 microg g(-1) for a sample from the Sokolov basin. A methanol/water mixture (1:1) extracted 15.1 - 38.7% of the total arsenic from Velenje basin samples but only 2.2-7.1% from Sokolov and Trbovlje basin samples. Extracts from the Velenje basin samples contained mainly the tetramethylarsonium ion (0.14 - 0.92 microg g(-1)) with considerable amounts of arsenate (0.15 - 0.85 microg g(-1)) and monomethyl arsonic acid 0.04 - 0.27 microg g(-1)). In methanol/water extracts from samples from the Sokolov and Trbovlje basins inorganic arsenic (arsenate) prevailed (0.26 - 37.1 microg g(-1)), but at least trace amounts of organic arsenic compounds were found as well. It is likely that biogeochemical degradation of organic material is related to the unexpected organoarsenic compounds found in low-rank coals. However, it should also not be ruled out that abiogenic synthesis could have taken place in the carbon-rich environment under the harsh conditions present (elevated temperature and pressure).
- MeSH
- arsen izolace a purifikace MeSH
- arsenikové přípravky izolace a purifikace MeSH
- izotopy dusíku analýza MeSH
- izotopy uhlíku analýza MeSH
- kovy analýza MeSH
- uhlí analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- Slovinsko MeSH
In the present study, bacterial isolates were screened for arsenic resistance efficiency. Environmental isolates were isolated from arsenic-rich soil samples (i.e., from Rajnandgaon district of Chhattisgarh state, India). Amplification and sequencing of 16S rRNA gene revealed that the isolates were of Bacillus firmus RSN1, Brevibacterium senegalense RSN2, Enterobacter cloacae RSN3, Stenotrophomonas pavanii RSN6, Achromobacter mucicolens RSN7, and Ochrobactrum intermedium RSN10. Arsenite efflux gene (arsB) was successfully amplified in E. cloacae RSN3. Atomic absorption spectroscopy (AAS) analysis showed an absorption of 32.22% arsenic by the RSN3 strain. Furthermore, results of scanning electron microscopy (SEM) for morphological variations revealed an initial increase in the cell size at 1 mM sodium arsenate; however, it was decreased at 10 mM concentration in comparison to control. This change of the cell size in different metal concentrations was due to the uptake and expulsion of the metal from the cell, which also confirmed the arsenite efflux system.
Arsenates, when present in water resources, constitute a risk to human health. In order to remove them, various technologies have been developed; out of them, sorption approach is widely adopted employing a wide spectrum of suitable sorbent materials. Nanoparticles of iron oxide are frequently used due to a high surface area and ability to control them by external magnetic field. In this work, we report on a simple and cheap synthesis of ultrafine iron(III) oxide nanoparticles with a narrow size distribution and their exploitation in the field of arsenate removal from aqueous environment. It is shown that the adsorption capacity is enhanced by a mesoporous nature of nanoparticle arrangement in their system due to strong magnetic interactions they evolve between nanoparticles. A complete arsenate removal is achieved at Fe/As ratio equal to ∼20/1 and at pH in the range from 5 to 7.6. Under these conditions, the arsenates are completely removed within several minutes of treatment. Among iron-oxide-based nanosystems synthesized and employed in arsenate remediation issues so far, our assembly of iron(III) oxide nanoparticles shows the highest Freundlich adsorption coefficient and equilibrium sorption capacity under conditions maintained. Taking into account simple and low-cost preparation procedure, product high yields, almost monodispersed character, room-temperature superparamagnetic behavior, and strong magnetic response under small applied magnetic fields, the synthesized iron(III) oxide nanoparticles can be regarded as a promising candidate for exploitation in the field of removing undesired toxic pollutants from various real water systems.
This review deals with speciation analysis of arsenic based on hydride generation and coupled with analytical atomic spectrometry. Three basic on-line approaches to speciation analysis of arsenic are defined: (a) selective hydride generation, (b) postcolumn hydride generation and (c) generation of methyl substituted arsanes. All of the approaches are discussed with the focus on the latest advances in those fields.
- MeSH
- arsen * analýza MeSH
- spektrální analýza metody MeSH
- Publikační typ
- práce podpořená grantem MeSH
Extremely arsenic-rich acid mine waters have developed by weathering of native arsenic in a sulfide-poor environment on the 10th level of the Svornost mine in Jáchymov (Czech Republic). Arsenic rapidly oxidizes to arsenolite (As2O3), and there are droplets of liquid on the arsenolite crust with high As concentration (80,000-130,000 mg·L(-1)), pH close to 0, and density of 1.65 g·cm(-1). According to the X-ray absorption spectroscopy on the frozen droplets, most of the arsenic is As(III) and iron is fully oxidized to Fe(III). The EXAFS spectra on the As K edge can be interpreted in terms of arsenic polymerization in the aqueous solution. The secondary mineral that precipitates in the droplets is kaatialaite [Fe(3+)(H2AsO4)3·5H2O]. Other unusual minerals associated with the arsenic lens are běhounekite [U(4+)(SO4)2·4H2O], štěpite [U(4+)(AsO3OH)2·4H2O], vysokýite [U(4+)[AsO2(OH)2]4·4H2O], and an unnamed phase (H3O)(+)2(UO2)2(AsO4)2·nH2O. The extremely low cell densities and low microbial biomass have led to insufficient amounts of DNA for downstream polymerase chain reaction amplification and clone library construction. We were able to isolate microorganisms on oligotrophic media with pH ∼ 1.5 supplemented with up to 30 mM As(III). These microorganisms were adapted to highly oligotrophic conditions which disabled long-term culturing under laboratory conditions. The extreme conditions make this environment unfavorable for intensive microbial colonization, but our first results show that certain microorganisms can adapt even to these harsh conditions.
- MeSH
- arsen analýza MeSH
- arsenikové přípravky chemie MeSH
- chemické látky znečišťující vodu analýza chemie MeSH
- geologie MeSH
- hornictví * MeSH
- minerály analýza chemie MeSH
- oxid arsenitý MeSH
- oxidace-redukce MeSH
- oxidy chemie MeSH
- podzemní voda chemie mikrobiologie MeSH
- rentgenová absorpční spektroskopie MeSH
- voda chemie MeSH
- železité sloučeniny analýza MeSH
- železo chemie metabolismus MeSH
- životní prostředí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
