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Sample records for arsenic hydrides

  1. Arsenic Speciation of Waters from the Aegean Region, Turkey by Hydride Generation: Atomic Absorption Spectrometry.

    Science.gov (United States)

    Çiftçi, Tülin Deniz; Henden, Emur

    2016-08-01

    Arsenic in drinking water is a serious problem for human health. Since the toxicity of arsenic species As(III) and As(V) is different, it is important to determine the concentrations separately. Therefore, it is necessary to develop an accurate and sensitive method for the speciation of arsenic. It was intended with this work to determine the concentrations of arsenic species in water samples collected from Izmir, Manisa and nearby areas. A batch type hydride generation atomic absorption spectrometer was used. As(V) gave no signal under the optimal measurement conditions of As(III). A certified reference drinking water was analyzed by the method and the results showed excellent agreement with the reported values. The procedure was applied to 34 water samples. Eleven tap water, two spring water, 19 artesian well water and two thermal water samples were analyzed under the optimal conditions. PMID:27236436

  2. Continuous flow hydride generation-atomic fluorescence spectrometric determination and speciation of arsenic in wine

    International Nuclear Information System (INIS)

    Methods for the atomic fluorescence spectrometric (AFS) determination of total arsenic and arsenic species in wines based on continuous flow hydride generation (HG) with atomization in miniature diffusion flame (MDF) are described. For hydride-forming arsenic, L-cysteine is used as reagent for pre-reduction and complexation of arsenite, arsenate, monomethylarsonate and dimethylarsinate. Concentrations of hydrochloric acid and tetrahydroborate are optimized in order to minimize interference by ethanol. Procedure permits determination of the sum of these four species in 5-10-fold diluted samples with limit of detection (LOD) 0.3 and 0.6 μg l-1 As in white and red wines, respectively, with precision between 2% and 8% RSD at As levels within 0.5-10 μg l-1. Selective arsine generation from different reaction media is used for non-chromatographic determination of arsenic species in wines: citrate buffer at pH 5.1 for As(III); 0.2 mol l-1 acetic acid for arsenite + dimethylarsinate (DMA); 8 mol l-1 HCl for total inorganic arsenic [As(III) + As(V)]; and monomethylarsonate (MMA) calculated by difference. Calibration with aqueous and ethanol-matched standard solutions of As(III) is used for 10- and 5-fold diluted samples, respectively. The LODs are 0.4 μg l-1 for As(III) and 0.3 μg l-1 for the other three As species and precision is within 4-8% RSDs. Arsenic species in wine were also determined by coupling of ion chromatographic separation on an anion exchange column and HG-flame AFS detection. Methods were validated by means of recovery studies and comparative analyses by HG-AFS and electrothermal atomic absorption spectrometry after microwave digestion. The LODs were 0.12, 0.27, 0.15 and 0.13 μg l-1 (as As) and RSDs were 2-6%, 5-9%, 3-7% and 2-5% for As(III), As(V), MMA and DMA arsenic species, respectively. Bottled red and white wines from Bulgaria, Republic of Macedonia and Italy were analyzed by non-chromatographic and chromatographic procedures and the As

  3. Organic solvents as interferents in arsenic determination by hydride generation atomic absorption spectrometry with flame atomization

    Science.gov (United States)

    Karadjova, Irina B.; Lampugnani, Leonardo; Dědina, Jiri; D'Ulivo, Alessandro; Onor, Massimo; Tsalev, Dimiter L.

    2006-05-01

    Interference effects of various organic solvents miscible with water on arsenic determination by hydride generation atomic absorption spectrometry have been studied. Arsine was chemically generated in continuous flow hydride generation system and atomized by using a flame atomizer able to operate in two modes: miniature diffusion flame and flame-in-flame. The effects of experimental variables and atomization mode were investigated: tetrahydroborate and hydrochloric acid concentrations, argon, hydrogen and oxygen supply rates for the microflame, and the distance from the atomization region to the observation zone. The nature of the species formed in the flame due to the pyrolysis of organic solvent vapors entering the flame volume together with arsine is discussed. The observed signal depression in the presence of organic solvents has been mainly attributed to the atomization interference due to heterogeneous gas-solid reaction between the free arsenic atoms and finely dispersed carbon particles formed by carbon radicals recombination. The best tolerance to interferences was obtained by using flame-in-flame atomization (5-10 ml min - 1 of oxygen flow rate), together with higher argon and hydrogen supply rates and elevated observation heights.

  4. Speciation of arsenic(III)/arsenic(V) and selenium(IV)/ selenium(VI) using coupled ion chromatography - hydride generation atomic absorption spectrometry

    Science.gov (United States)

    Simple analytical methods have been developed to speciate inorganic arsenic and selenium in the ppb range using coupled ion chromatography-hydride generation atomic absorption spectrometry. Because of the differences in toxicity and adsorption behavior, determinations of the redox states arsenite A...

  5. Arsenic speciation by hydride generation-quartz furnace atomic absorption spectrometry. Optimization of analytical parameters and application to environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Molenat, N.; Astruc, A.; Holeman, M.; Pinel, R. [Laboratoire de Chimie Analytique Bioinorganique et Environnement, Dept. de Chimie, Faculte des Sciences et Techniques, 64 - Pau (France); Maury, G. [Montpellier-2 Univ., 34 (France). Dept. de Chimie Organique Fine

    1999-11-01

    Analytical parameters of hydride generation, trapping, gas chromatography and atomic absorption spectrometry detection in a quartz cell furnace (HG/GC/QFAAS) device have been optimized in order to develop an efficient and sensitive method for arsenic compounds speciation. Good performances were obtained with absolute detection limits in the range of 0.1 - 0.5 ng for arsenite, arsenate, mono-methyl-arsonic acid (MMAA), dimethyl-arsinic acid (DMAA) and trimethyl-arsine oxide (TMAO). A pH selective reduction for inorganic arsenic speciation was successfully reported. Application to the accurate determination of arsenic compounds in different environmental samples was performed. (authors)

  6. Speciation analysis of arsenic in biological matrices by automated hydride generation-cryotrapping-atomic absorption spectrometry with multiple microflame quartz tube atomizer (multiatomizer).

    Science.gov (United States)

    This paper describes an automated system for the oxidation state specific speciation of inorganic and methylated arsenicals by selective hydride generation - cryotrapping- gas chromatography - atomic absorption spectrometry with the multiatomizer. The corresponding arsines are ge...

  7. Arsenic in marine tissues — The challenging problems to electrothermal and hydride generation atomic absorption spectrometry

    Science.gov (United States)

    Karadjova, Irina B.; Petrov, Panayot K.; Serafimovski, Ivan; Stafilov, Trajče; Tsalev, Dimiter L.

    2007-03-01

    Analytical problems in determination of arsenic in marine tissues are addressed. Procedures for the determination of total As in solubilized or extracted tissues with tetramethylammonium hydroxide and methanol have been elaborated. Several typical lyophilized tissues were used: NIST SRM 1566a 'Oyster Tissue', BCR-60 CRM 'Trace Elements in an Aquatic Plant ( Lagarosiphon major)', BCR-627 'Forms of As in Tuna Fish Tissue', IAEA-140/TM 'Sea Plant Homogenate', NRCC DOLT-1 'Dogfish Liver' and two representatives of the Black Sea biota, Mediterranean mussel ( Mytilus galloprovincialis) and Brown algae ( Cystoseira barbata). Tissues (nominal 0.3 g) were extracted in tetramethylammonium hydroxide (TMAH) 1 ml of 25% m/v TMAH and 2 ml of water) or 5 ml of aqueous 80% v/v methanol (MeOH) in closed vessels in a microwave oven at 50 °C for 30 min. Arsenic in solubilized or extracted tissues was determined by electrothermal atomic absorption spectrometry (ETAAS) after appropriate dilution (nominally to 25 ml, with further dilution as required) under optimal instrumental parameters (pyrolysis temperature 900 °C and atomization temperature 2100 °C) with 1.5 μg Pd as modifier on Zr-Ir treated platform. Platforms have been pre-treated with 2.7 μmol of zirconium and then with 0.10 μmol of iridium which served as a permanent chemical modifier in direct ETAAS measurements and as an efficient hydride sequestration medium in flow injection hydride generation (FI-HG)-ETAAS. TMAH and methanol extract 96-108% and 51-100% of As from CRMs. Various calibration approaches have been considered and critically evaluated. The effect of species-dependent slope of calibration graph or standard additions plot for total As determination in a sample comprising of several individual As species with different ETAAS behavior has been considered as a kind of 'intrinsic element speciation interference' that cannot be completely overcome by standard additions technique. Calibration by means of CRMs has

  8. Arsenic in marine tissues - The challenging problems to electrothermal and hydride generation atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Karadjova, Irina B.; Petrov, Panayot K. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria); Serafimovski, Ivan [Food Institute, Faculty of Veterinary Medicine, Sts. Cyril and Methodius University, P.O. Box 95, MK-1000, Skopje (Macedonia, The Former Yugoslav Republic of); Stafilov, Trajce [Institute of Chemistry, Faculty of Science, Sts. Cyril and Methodius University, P.O. Box 162, MK-1000, Skopje (Macedonia, The Former Yugoslav Republic of); Tsalev, Dimiter L. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria)], E-mail: tsalev@chem.uni-sofia.bg

    2007-03-15

    Analytical problems in determination of arsenic in marine tissues are addressed. Procedures for the determination of total As in solubilized or extracted tissues with tetramethylammonium hydroxide and methanol have been elaborated. Several typical lyophilized tissues were used: NIST SRM 1566a 'Oyster Tissue', BCR-60 CRM 'Trace Elements in an Aquatic Plant (Lagarosiphon major)', BCR-627 'Forms of As in Tuna Fish Tissue', IAEA-140/TM 'Sea Plant Homogenate', NRCC DOLT-1 'Dogfish Liver' and two representatives of the Black Sea biota, Mediterranean mussel (Mytilus galloprovincialis) and Brown algae (Cystoseira barbata). Tissues (nominal 0.3 g) were extracted in tetramethylammonium hydroxide (TMAH) 1 ml of 25% m/v TMAH and 2 ml of water) or 5 ml of aqueous 80% v/v methanol (MeOH) in closed vessels in a microwave oven at 50 deg. C for 30 min. Arsenic in solubilized or extracted tissues was determined by electrothermal atomic absorption spectrometry (ETAAS) after appropriate dilution (nominally to 25 ml, with further dilution as required) under optimal instrumental parameters (pyrolysis temperature 900 deg. C and atomization temperature 2100 deg. C) with 1.5 {mu}g Pd as modifier on Zr-Ir treated platform. Platforms have been pre-treated with 2.7 {mu}mol of zirconium and then with 0.10 {mu}mol of iridium which served as a permanent chemical modifier in direct ETAAS measurements and as an efficient hydride sequestration medium in flow injection hydride generation (FI-HG)-ETAAS. TMAH and methanol extract 96-108% and 51-100% of As from CRMs. Various calibration approaches have been considered and critically evaluated. The effect of species-dependent slope of calibration graph or standard additions plot for total As determination in a sample comprising of several individual As species with different ETAAS behavior has been considered as a kind of 'intrinsic element speciation interference' that cannot be completely

  9. Determination of Inorganic Arsenic Species by Electrochemical Hydride Generation Atomic Absorption Spectrometry with Selective Electrochemical Reduction

    Institute of Scientific and Technical Information of China (English)

    LI Xun; WANG Zheng-Hao

    2007-01-01

    A new direct procedure for the determination of inorganic arsenic species was developed by electrochemical hydride generation atomic absorption spectrometry (EcHG-AAS) with selective electrochemical reduction. The determination of inorganic arsenic species is based on the fact that As(Ⅲ) shows significantly higher absorbance at low electrolytic currents than As(Ⅴ) in 0.3 mol·L-1 H2SO4.The electrolytic current used for the determination of As(Ⅲ) without considerable interferences of As(V) was 0.4 A, whereas the current for the determination of As(Ⅲ)and As(V) was 1.2 A. For equal concentrations of As(Ⅲ) and As(V) in a sample, the interferences of As(V) during the As(Ⅲ) determination were smaller than 5%. The absorbance for As(V) could be calculated by subtracting that for As(Ⅲ) measured at 0.4 A from the total absorbance for As(Ⅲ) and As(V) measured at 1.2 A, and then the concentration of As(V) can be obtained by its calibration curve at 1.2 A. The methodology developed provided the detection limits of 0.3 and 0.6 ng·ml-1 for As(Ⅲ) and As(V) respectively.The relative standrad deviations were of 3.5% for 20 ng·ml-1 As(Ⅲ) and 302% for 20 ng·ml-1 As(V).The method was successfully applied to determination of soluble inorganic arsenic species in Chinese medicine.

  10. Determination of arsenic and selenium by hydride generation and headspace solid phase microextraction coupled with optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tyburska, Anna; Jankowski, Krzysztof, E-mail: kj@ch.pw.edu.pl; Rodzik, Agnieszka

    2011-07-15

    A hydride generation headspace solid phase microextraction technique has been developed in combination with optical emission spectrometry for determination of total arsenic and selenium. Hydrides were generated in a 10 mL volume septum-sealed vial and subsequently collected onto a polydimethylsiloxane/Carboxen solid phase microextraction fiber from the headspace of sample solution. After completion of the sorption, the fiber was transferred into a thermal desorption unit and the analytes were vaporized and directly introduced into argon inductively coupled plasma or helium microwave induced plasma radiation source. Experimental conditions of hydride formation reaction as well as sorption and desorption of analytes have been optimized showing the significant effect of the type of the solid phase microextraction fiber coating, the sorption time and hydrochloric acid concentration of the sample solution on analytical characteristics of the method developed. The limits of detection of arsenic and selenium were 0.1 and 0.8 ng mL{sup -1}, respectively. The limit of detection of selenium could be improved further using biosorption with baker's yeast Saccharomyces cerevisiae for analyte preconcentration. The technique was applied for the determination of total As and Se in real samples.

  11. Quantifying uncertainty in the measurement of arsenic in suspended particulate matter by Atomic Absorption Spectrometry with hydride generator

    Directory of Open Access Journals (Sweden)

    Ahuja Tarushee

    2011-04-01

    Full Text Available Abstract Arsenic is the toxic element, which creates several problems in human being specially when inhaled through air. So the accurate and precise measurement of arsenic in suspended particulate matter (SPM is of prime importance as it gives information about the level of toxicity in the environment, and preventive measures could be taken in the effective areas. Quality assurance is equally important in the measurement of arsenic in SPM samples before making any decision. The quality and reliability of the data of such volatile elements depends upon the measurement of uncertainty of each step involved from sampling to analysis. The analytical results quantifying uncertainty gives a measure of the confidence level of the concerned laboratory. So the main objective of this study was to determine arsenic content in SPM samples with uncertainty budget and to find out various potential sources of uncertainty, which affects the results. Keeping these facts, we have selected seven diverse sites of Delhi (National Capital of India for quantification of arsenic content in SPM samples with uncertainty budget following sampling by HVS to analysis by Atomic Absorption Spectrometer-Hydride Generator (AAS-HG. In the measurement of arsenic in SPM samples so many steps are involved from sampling to final result and we have considered various potential sources of uncertainties. The calculation of uncertainty is based on ISO/IEC17025: 2005 document and EURACHEM guideline. It has been found that the final results mostly depend on the uncertainty in measurement mainly due to repeatability, final volume prepared for analysis, weighing balance and sampling by HVS. After the analysis of data of seven diverse sites of Delhi, it has been concluded that during the period from 31st Jan. 2008 to 7th Feb. 2008 the arsenic concentration varies from 1.44 ± 0.25 to 5.58 ± 0.55 ng/m3 with 95% confidence level (k = 2.

  12. Determination of total arsenic in coal and wood using oxygen flask combustion method followed by hydride generation atomic absorption spectrometry

    International Nuclear Information System (INIS)

    A simple and sensitive procedure for the determination of total arsenic in coal and wood was conducted by use of oxygen flask combustion (OFC) followed by hydride generation atomic absorption spectrometry (HGAAS). The effect of various items (composition of absorbent, standing time between the combustion and filtration, particle size and mass of sample) was investigated. Under the optimized conditions of the OFC method, nine certified reference materials were analyzed, and the values of arsenic concentration obtained by this method were in good accordance with the certified values. The limit of detection (LOD) and relative standard deviation (RSD) of the method were 0.29 μg g-1 and less than 8%, respectively. In addition, eight kinds of coals and four chromated copper arsenate (CCA)-treated wood wastes were analyzed by the present method, and the data were compared to those from the microwave-acid digestion (MW-AD) method. The determination of arsenic in solid samples was discussed in terms of applicable scope and concentration range of arsenic.

  13. Determination of arsenic speciation in sulfidic waters by Ion Chromatography Hydride-Generation Atomic Fluorescence Spectrometry (IC-HG-AFS).

    Science.gov (United States)

    Keller, Nicole S; Stefánsson, Andri; Sigfússon, Bergur

    2014-10-01

    A method for the analysis of arsenic species in aqueous sulfide samples is presented. The method uses an ion chromatography system connected with a Hydride-Generation Atomic Fluorescence Spectrometer (IC-HG-AFS). With this method inorganic As(III) and As(V) species in water samples can be analyzed, including arsenite (HnAs(III)O3(n-3)), thioarsenite (HnAs(III)S3(n-3)), arsenate (HnAs(V)O4(n-3)), monothioarsenate (HnAs(V)SO3(n-3)), dithioarsenate (HnAs(V)S2O2(n-3)), trithioarsenate (HnAs(V)S3O(n-3)) and tetrathioarsenate (HnAs(V)S4(n-3)). The peak identification and retention times were determined based on standard analysis of the various arsenic compounds. The analytical detection limit was ~1-3 µg L(-1) (LOD), depending on the quality of the baseline. This low detection limit makes this method also applicable to discriminate between waters meeting the drinking water standard of max. 10 µg L(-1) As, and waters that do not meet this standard. The new method was successfully applied for on-site determination of arsenic species in natural sulfidic waters, in which seven species were unambiguously identified.

  14. Arsenic and antimony determination in refined and unrefined table salts by means of hydride generation atomic absorption spectrometry--comparison of sample decomposition and determination methods

    OpenAIRE

    AKSUNER, Nur; TİRTOM, Vedia Nüket; HENDEN, Emür

    2011-01-01

    An evaluation was made of different digestion methods for the determination of arsenic and antimony in table salt samples prior to hydride generation atomic absorption spectrometric analysis. Microwave acid digestion, classical wet digestion, dry ashing, and fusion were applied to the decomposition of salt samples and optimum conditions were investigated. Samples were decomposed by changing heating time, digestion techniques, and the amount and composition of acid, and then the concen...

  15. The determination of arsenic, selenium, antimony, and tin in complex environmental samples by hydride generation AAS

    International Nuclear Information System (INIS)

    Hydride generation techniques are used routinely for the determination of As, Se, Sb and Sn in water samples. Advantages include high sensitivity, simplicity, and relative freedom from interferences. Continuous-flow designs greatly reduce analysis time as well as improve precision and allow for automation. However the accurate analysis of more complex environmental samples such as industrial sludges, soil samples, river sediments, and fly ash remains difficult. Numerous contributing factors influence the accuracy of the hydride technique. Sample digestion methods and sample preparation procedures are of critical importance. The digestion must adequately solubilize the elements of interest without loss by volatilization. Sample preparation procedures that guarantee the proper analyte oxidation state and eliminate the nitric acid and inter-element interferences are needed. In this study, difficult environmental samples were analyzed for As, Se, Sb, and Sn by continuous flow hydride generation. Sample preparation methods were optimized to eliminate interferences. The results of spike recovery studies will be presented. Data from the analysis of the same samples by graphite furnace AAS will be presented for comparison of accuracy, precision, and analysis time

  16. Determination of ultra trace arsenic species in water samples by hydride generation atomic absorption spectrometry after cloud point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Ulusoy, Halil Ibrahim, E-mail: hiulusoy@yahoo.com [University of Cumhuriyet, Faculty of Science, Department of Chemistry, TR-58140, Sivas (Turkey); Akcay, Mehmet; Ulusoy, Songuel; Guerkan, Ramazan [University of Cumhuriyet, Faculty of Science, Department of Chemistry, TR-58140, Sivas (Turkey)

    2011-10-10

    Graphical abstract: The possible complex formation mechanism for ultra-trace As determination. Highlights: {yields} CPE/HGAAS system for arsenic determination and speciation in real samples has been applied first time until now. {yields} The proposed method has the lowest detection limit when compared with those of similar CPE studies present in literature. {yields} The linear range of the method is highly wide and suitable for its application to real samples. - Abstract: Cloud point extraction (CPE) methodology has successfully been employed for the preconcentration of ultra-trace arsenic species in aqueous samples prior to hydride generation atomic absorption spectrometry (HGAAS). As(III) has formed an ion-pairing complex with Pyronine B in presence of sodium dodecyl sulfate (SDS) at pH 10.0 and extracted into the non-ionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-114). After phase separation, the surfactant-rich phase was diluted with 2 mL of 1 M HCl and 0.5 mL of 3.0% (w/v) Antifoam A. Under the optimized conditions, a preconcentration factor of 60 and a detection limit of 0.008 {mu}g L{sup -1} with a correlation coefficient of 0.9918 was obtained with a calibration curve in the range of 0.03-4.00 {mu}g L{sup -1}. The proposed preconcentration procedure was successfully applied to the determination of As(III) ions in certified standard water samples (TMDA-53.3 and NIST 1643e, a low level fortified standard for trace elements) and some real samples including natural drinking water and tap water samples.

  17. Cloud point extraction for trace inorganic arsenic speciation analysis in water samples by hydride generation atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shan, E-mail: ls_tuzi@163.com; Wang, Mei, E-mail: wmei02@163.com; Zhong, Yizhou, E-mail: yizhz@21cn.com; Zhang, Zehua, E-mail: kazuki.0101@aliyun.com; Yang, Bingyi, E-mail: e_yby@163.com

    2015-09-01

    A new cloud point extraction technique was established and used for the determination of trace inorganic arsenic species in water samples combined with hydride generation atomic fluorescence spectrometry (HGAFS). As(III) and As(V) were complexed with ammonium pyrrolidinedithiocarbamate and molybdate, respectively. The complexes were quantitatively extracted with the non-ionic surfactant (Triton X-114) by centrifugation. After addition of antifoam, the surfactant-rich phase containing As(III) was diluted with 5% HCl for HGAFS determination. For As(V) determination, 50% HCl was added to the surfactant-rich phase, and the mixture was placed in an ultrasonic bath at 70 °C for 30 min. As(V) was reduced to As(III) with thiourea–ascorbic acid solution, followed by HGAFS. Under the optimum conditions, limits of detection of 0.009 and 0.012 μg/L were obtained for As(III) and As(V), respectively. Concentration factors of 9.3 and 7.9, respectively, were obtained for a 50 mL sample. The precisions were 2.1% for As(III) and 2.3% for As(V). The proposed method was successfully used for the determination of trace As(III) and As(V) in water samples, with satisfactory recoveries. - Highlights: • Cloud point extraction was firstly established to determine trace inorganic arsenic(As) species combining with HGAFS. • Separate As(III) and As(V) determinations improve the accuracy. • Ultrasonic release of complexed As(V) enables complete As(V) reduction to As(III). • Direct HGAFS analysis can be performed.

  18. Cloud point extraction for trace inorganic arsenic speciation analysis in water samples by hydride generation atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    A new cloud point extraction technique was established and used for the determination of trace inorganic arsenic species in water samples combined with hydride generation atomic fluorescence spectrometry (HGAFS). As(III) and As(V) were complexed with ammonium pyrrolidinedithiocarbamate and molybdate, respectively. The complexes were quantitatively extracted with the non-ionic surfactant (Triton X-114) by centrifugation. After addition of antifoam, the surfactant-rich phase containing As(III) was diluted with 5% HCl for HGAFS determination. For As(V) determination, 50% HCl was added to the surfactant-rich phase, and the mixture was placed in an ultrasonic bath at 70 °C for 30 min. As(V) was reduced to As(III) with thiourea–ascorbic acid solution, followed by HGAFS. Under the optimum conditions, limits of detection of 0.009 and 0.012 μg/L were obtained for As(III) and As(V), respectively. Concentration factors of 9.3 and 7.9, respectively, were obtained for a 50 mL sample. The precisions were 2.1% for As(III) and 2.3% for As(V). The proposed method was successfully used for the determination of trace As(III) and As(V) in water samples, with satisfactory recoveries. - Highlights: • Cloud point extraction was firstly established to determine trace inorganic arsenic(As) species combining with HGAFS. • Separate As(III) and As(V) determinations improve the accuracy. • Ultrasonic release of complexed As(V) enables complete As(V) reduction to As(III). • Direct HGAFS analysis can be performed

  19. Separation of trace antimony and arsenic prior to hydride generation atomic absorption spectrometric determination

    International Nuclear Information System (INIS)

    A separation method utilizing a synthetic zeolite (mordenite) was developed in order to eliminate the gas phase interference of Sb(III) on As(III) during quartz furnace hydride generation atomic absorption spectrometric (HGAAS) determination. The efficiency of the proposed separation method in the reduction of suppression effects of transition metal ions on As(III) signal was also investigated. Among the volatile hydride-forming elements and their different oxidation states tested (Sb(III), Sb(V), Se(IV), Se(VI), Te(IV), and Te(VI)), only Sb(III) was found to have a signal depression effect even at low (μg l-1) concentrations under the experimental conditions employed. It has been shown that mordenite adsorbs Sb(III) quantitatively, even at a concentration of 1000 μg l-1, at pHs greater than two, and also, it reduces the initial concentrations of the transition metal ions to lower levels which can be tolerated in many studies. The adsorption of Sb(III) on mordenite follows the Freundlich isotherm and is endothermic in nature

  20. Arsenic species analysis in porewaters and sediments using hydride generation atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    LIAO Meng-xia; DENG Tian-long

    2006-01-01

    It was observed that the atomic fluorescence emission due to As(Ⅴ) could has a 10% to 40% of fluorescence emission signal during the determination of As(Ⅲ) in the mixture of As(Ⅲ) and As(Ⅴ). Besides, interferes from heavy metals such as Pb(Ⅱ),Cu(Ⅱ) can cause severe increase of the signals as compared to the insignificant effects caused by Cd(Ⅱ), Zn(Ⅱ), Mn(Ⅱ) and Fe(Ⅲ). On the basis of further studies, the masking agent of 8-hydroxyquinoline was used as an efficient agent to eliminate interference of As(Ⅴ)emission and the heavy metal of Cu2+ and Pb2+ in the measurements of arsenic species. After a series standard additions and CRM researches, a sensitive and interference-free analytical procedure was developed for the speciation of arsenic in samples ofporewaters and sediments in Poyang Lake, China.

  1. Cloud point extraction for trace inorganic arsenic speciation analysis in water samples by hydride generation atomic fluorescence spectrometry

    Science.gov (United States)

    Li, Shan; Wang, Mei; Zhong, Yizhou; Zhang, Zehua; Yang, Bingyi

    2015-09-01

    A new cloud point extraction technique was established and used for the determination of trace inorganic arsenic species in water samples combined with hydride generation atomic fluorescence spectrometry (HGAFS). As(III) and As(V) were complexed with ammonium pyrrolidinedithiocarbamate and molybdate, respectively. The complexes were quantitatively extracted with the non-ionic surfactant (Triton X-114) by centrifugation. After addition of antifoam, the surfactant-rich phase containing As(III) was diluted with 5% HCl for HGAFS determination. For As(V) determination, 50% HCl was added to the surfactant-rich phase, and the mixture was placed in an ultrasonic bath at 70 °C for 30 min. As(V) was reduced to As(III) with thiourea-ascorbic acid solution, followed by HGAFS. Under the optimum conditions, limits of detection of 0.009 and 0.012 μg/L were obtained for As(III) and As(V), respectively. Concentration factors of 9.3 and 7.9, respectively, were obtained for a 50 mL sample. The precisions were 2.1% for As(III) and 2.3% for As(V). The proposed method was successfully used for the determination of trace As(III) and As(V) in water samples, with satisfactory recoveries.

  2. Comparative oxidation state specific analysis of arsenic species by high-performance liquid chromatography- inductively coupled plasma-mass spectrometry and hydride generation-cryotrapping-atomic absorption spectrometry

    OpenAIRE

    Currier, J. M.; Saunders, R J; Ding, L.; Bodnar, W.; Cable, P.; Matoušek, T. (Tomáš); Creed, J. T.; Stýblo, M.

    2013-01-01

    The formation of methylarsonous acid (MAsIII) and dimethylarsinous acid (DMAsIII) in the course of inorganic arsenic (iAs) metabolism plays an important role in the adverse effects of chronic exposure to iAs. High-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) and hydride generation-cryotrapping-atomic absorption spectrometry (HG-CT-AAS) have been frequently used for the analysis of MAsIII and DMAsIII in biological samples. While HG-CT-AAS has con...

  3. Determination of arsenic by pervaporation-flow injection hydride generation and permanganate spectrophotometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Rupasinghe, Thusitha; Cardwell, Terence J.; Cattrall, Robert W.; Potter, Ian D.; Kolev, Spas D

    2004-05-17

    A novel pervaporation-flow injection (PFI) system for the determination of As(III) in aqueous samples at {mu}g l{sup -1} level is described. The analytical procedure involved stopping the acceptor stream and injecting acidified As(III) samples into a 0.3 M HCl stream which was mixed with a 0.14 M sodium borohydride in 0.025 M NaOH stream. The arsine generated was transported in the pervaporation unit across a semi-permeable membrane (1.5 mm thickness) into the static acceptor solution containing 1.0x10{sup -4} M KMnO{sub 4} in 0.1 M H{sub 2}SO{sub 4} where it was oxidised. The acceptor stream was restarted after 6.5 min, and the decrease in permanganate absorbance at 528 nm was monitored to determine the initial concentration of As(III) in the samples. The method is characterised by a linear calibration range from 0.25 to 2000 {mu}g l{sup -1}, a detection limit of 0.18 {mu}g l{sup -1} and a sampling frequency of 7 h{sup -1}. Samples containing As(V) were pre-treated with KI and HCl prior to injection to reduce As(V) to As(III). The effects of common anionic and cationic interferences, and the elimination of some metallic interferences using L-cysteine are discussed. The method was applied to the analysis of environmental waters and the results were in good agreement with hydride generation atomic absorption spectrometric data.

  4. [Study on Content Determination of Lead and Arsenic in Four Traditional Tibetan Medicine Prescription Preparations by Wet Digestion Flow Injection-Hydride Generation-Atomic Absorption Spectrometry].

    Science.gov (United States)

    Zheng, Zhi-yuan; Du, Yu-zhi; Zhang, Ming; Yu, Ming-jie; Li, Cen; Yang, Hong-xia; Zhao, Jing; Xia, Zheng-hua; Wei, Li-xin

    2015-04-01

    Four common traditional tibetan medicine prescription preparations "Anzhijinghuasan, Dangzuo, Renqingchangjue and Rannasangpei" in tibetan areas were selected as study objects in the present study. The purpose was to try to establish a kind of wet digestion and flow injection-hydride generation-atomic absorption spectrometry (FI-HAAS) associated analysis method for the content determinations of lead and arsenic in traditional tibetan medicine under optimized digestion and measurement conditions and determine their contents accurately. Under these optimum operating conditions, experimental results were as follows. The detection limits for lead and arsenic were 0.067 and 0.012 µg · mL(-1) respectively. The quantification limits for lead and arsenic were 0.22 and 0.041 µg · mL(-1) respectively. The linear ranges for lead and arsenic were 25-1,600 ng · mL(-1) (r = 0.9995) and 12.5-800 ng · mL(-1) (r = 0.9994) respectively. The degrees of precision(RSD) for lead and arsenic were 2.0% and 3.2% respectively. The recovery rates for lead and arsenic were 98.00%-99.98% and 96.67%-99.87% respectively. The content determination results of lead and arsenic in four traditional tibetan medicine prescription preparations were as fol- lows. The contents of lead and arsenic in Anzhijinghuasan are 0.63-0.67 µg · g(-1) and 0.32-0.33 µg · g(-1) in Anzhijinghua- san, 42.92-43.36 µg · g(-1) and 24.67-25.87 µg · g(-1) in Dangzuo, 1,611. 39-1,631.36 µg · g(-1) and 926.76-956.52 µg- g(-1) in Renqing Changjue, and 1,102.28-1,119.127 µg-g(-1) and 509.96-516.87 µg · g(-1) in Rannasangpei, respectively. This study established a method for content determination of lead and arsenic in traditional tibetan medicine, and determined the content levels of lead and arsenic in four tibetan medicine-prescription preparations accurately. In addition, these results also provide the basis for the safe and effective use of those medicines in clinic.

  5. Polar intermetallic compounds of the silicon and arsenic family elements and their ternary hydrides and fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Leon-Escamilla, E.A.

    1996-10-17

    An investigation has been made on the effects of hydrogen and fluoride in the solid state chemistry of alkaline-earth and divalent rare-earth metal pnictide (Pn) and tetrelide (Tt) phases A{sub 5}(Pn,Tt,){sub 3}Z{sub x}, where A = Ca, Sr, Ba, Sm, Eu, Yb; Pn = As, Sb, Bi; Tt = Si, Ge, Sn, Pb and Z = H, F. Several trivalent rare-earth-metal pnictides, RE{sub 5}Pn{sub 3} (RE = Y, La, Gd, Tb, Dy, Ho, Er, Tm) and alkaline-earth-metal trielides, A{sub 5}Tr{sub 3}Z{sub x} (Tr = Ga, In, Tl) have been included in an effort to complete observed structural trends. Two main experimental techniques were followed throughout this work, (a) reactions in absence of hydrogen or under continuous high vacuum, and (b) reactions with binary metal hydrides, AH{sub x}, in closed containers. The results demonstrate that all the phases reported with the {beta}-Yb{sub 5}Sb{sub 3}-type structure in the A{sub 5}Pn{sub 3} systems are hydrogen-stabilized compounds. Reactions in absence of hydrogen lead to compounds with the Mn{sub 5}Si{sub 3}-type structure. The structure type {beta}-Yb{sub 5}Sb{sub 3} (= Ca{sub 5}SB{sub 3}F) was found to be characteristic of ternary systems and inaccurately associated with phases that form in the Y{sub 5}Bi{sub 3}-type. A new series of isomorphous Zintl compounds with the Ca{sub 16}Sb{sub 11}-type structure were prepared and studied as well. All the alkaline-earth-metal tetrelides, A{sub 5}Tt{sub 3}, that crystallize in the Cr{sub 5}B{sub 3}-type structure can be interstitially derivatized by hydrogen or fluoride. Binary and ternary compounds were characterized by Guinier powder patterns, single crystal X-ray and powder neutron diffraction techniques. In an effort to establish property-structure relationships, electrical resistivity and magnetic measurements were performed on selected systems, and the results were explained in terms of the Zintl concepts, aided by extended Hueckel band calculations.

  6. SPECIATION OF SELENIUM AND ARSENIC COMPOUNDS BY CAPILLARY ELECTROPHORESIS WITH HYDRODYNAMICALLY MODIFIED ELECTROOSMOTIC FLOW AND ON-LINE REDUCTION OF SELENIUM(VI) TO SELENIUM(IV) WITH HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRIC DETECTION

    Science.gov (United States)

    Capillary electrophoresis (CE) with hydride generation inductively coupled plasma mass spectrometry was used to determine four arsenicals and two selenium species. Selenate (SeVI) was reduced on-line to selenite (SeIV') by mixing the CE effluent with concentrated HCl. A microporo...

  7. Evaluation of arsenic and selenium in Brazilian soluble coffee by inductively coupled plasma atomic emission spectrometry with hydride generation

    Directory of Open Access Journals (Sweden)

    Éder José dos Santos

    2001-09-01

    Full Text Available A method for the evaluation of arsenic and selenium in soluble coffee by inductively coupled plasma atomic emission spectrometry with continuous hydride generation to attend the Brazilian food legislation is described. Samples were digested with nitric acid and hydrogen peroxide in a focused microwave system. Slow heating eliminated nitric acid and selenium (VI was reduced to selenium (IV by addition of 6 mol/L hydrochloric acid and heating at 90° C under a reflux system. The influence of sample acidity on sensitivity was investigated. Hydrochloric acid 6 mol/L was the most suitable reaction medium. Practical detection limits of 2.0mug/L for As and 1.0mu g/L for Se were achieved and attended the Brazilian food legislation. The results of recoveries on spiked samples demonstrate the reliability and accuracy of the procedure.O presente trabalho descreve um método para determinação de arsênio e selênio em café solúvel por espectrometria de emissão atômica com plasma acoplado a geração de hidretos, com o objetivo de atender aos limites estabelecidos pela legislação Brasileira de alimentos. Digestões das amostras foram realizadas com ácido nítrico e peróxido de hidrogênio em sistema de microondas focalizadas. O excesso de ácido nítrico foi eliminado através de aquecimento lento e o selênio (VI foi reduzido a selênio (IV através de tratamento com ácido clorídrico 6 mol/L e aquecimento a 90° C em sistema de refluxo. A influência da acidez na sensibilidade foi investigada, sendo o meio mais estável a concentração de ácido clorídrico de 6 mol/L. Os limites de determinação foram de 2.0 mig/L para o As e 1.0 mig/L para o Se. Os resultados das amostras enriquecidas demonstram a precisão e exatidão do método proposto.

  8. An evaluation of the bioaccessibility of arsenic in corn and rice samples based on cloud point extraction and hydride generation coupled to atomic fluorescence spectrometry.

    Science.gov (United States)

    Castor, José Martín Rosas; Portugal, Lindomar; Ferrer, Laura; Hinojosa-Reyes, Laura; Guzmán-Mar, Jorge Luis; Hernández-Ramírez, Aracely; Cerdà, Víctor

    2016-08-01

    A simple, inexpensive and rapid method was proposed for the determination of bioaccessible arsenic in corn and rice samples using an in vitro bioaccessibility assay. The method was based on the preconcentration of arsenic by cloud point extraction (CPE) using o,o-diethyldithiophosphate (DDTP) complex, which was generated from an in vitro extract using polyethylene glycol tert-octylphenyl ether (Triton X-114) as a surfactant prior to its detection by atomic fluorescence spectrometry with a hydride generation system (HG-AFS). The CPE method was optimized by a multivariate approach (two-level full factorial and Doehlert designs). A photo-oxidation step of the organic species prior to HG-AFS detection was included for the accurate quantification of the total As. The limit of detection was 1.34μgkg(-1) and 1.90μgkg(-1) for rice and corn samples, respectively. The accuracy of the method was confirmed by analyzing certified reference material ERM BC-211 (rice powder). The corn and rice samples that were analyzed showed a high bioaccessible arsenic content (72-88% and 54-96%, respectively), indicating a potential human health risk.

  9. An evaluation of the bioaccessibility of arsenic in corn and rice samples based on cloud point extraction and hydride generation coupled to atomic fluorescence spectrometry.

    Science.gov (United States)

    Castor, José Martín Rosas; Portugal, Lindomar; Ferrer, Laura; Hinojosa-Reyes, Laura; Guzmán-Mar, Jorge Luis; Hernández-Ramírez, Aracely; Cerdà, Víctor

    2016-08-01

    A simple, inexpensive and rapid method was proposed for the determination of bioaccessible arsenic in corn and rice samples using an in vitro bioaccessibility assay. The method was based on the preconcentration of arsenic by cloud point extraction (CPE) using o,o-diethyldithiophosphate (DDTP) complex, which was generated from an in vitro extract using polyethylene glycol tert-octylphenyl ether (Triton X-114) as a surfactant prior to its detection by atomic fluorescence spectrometry with a hydride generation system (HG-AFS). The CPE method was optimized by a multivariate approach (two-level full factorial and Doehlert designs). A photo-oxidation step of the organic species prior to HG-AFS detection was included for the accurate quantification of the total As. The limit of detection was 1.34μgkg(-1) and 1.90μgkg(-1) for rice and corn samples, respectively. The accuracy of the method was confirmed by analyzing certified reference material ERM BC-211 (rice powder). The corn and rice samples that were analyzed showed a high bioaccessible arsenic content (72-88% and 54-96%, respectively), indicating a potential human health risk. PMID:26988526

  10. Development of an analytical method for the determination of arsenic in gasoline samples by hydride generation-graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Emilene M. [Universidade Federal do Pampa, Bage, RS (Brazil); Universidade Federal de Pelotas, Pelotas, RS (Brazil); Dessuy, Morgana B.; Boschetti, Wiliam [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves, 9500, 91501-970 Porto Alegre, RS (Brazil); Vale, Maria Goreti R., E-mail: mgrvale@ufrgs.br [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves, 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciencia e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Ferreira, Sergio L.C. [Instituto Nacional de Ciencia e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Instituto de Quimica, Universidade Federal da Bahia, Salvador, BA (Brazil); Welz, Bernhard [Instituto Nacional de Ciencia e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil)

    2012-05-15

    The purpose of the present work was to optimize the conditions for the determination of arsenic in gasoline with hydride generation-graphite furnace atomic absorption spectrometry after acid digestion using a full two-level factorial design with center point. The arsine was generated in a batch system and collected in a graphite tube coated with 150 {mu}g Ir as a permanent modifier. The sample volume, the pre-reduction conditions, the temperature program and modifier mass were kept fixed for all experiments. The estimated main effects were: reducing agent concentration (negative effect), acid concentration (negative effect) and trapping temperature (positive effect). It was observed that there were interactions between the variables. Moreover, the curvature was significant, indicating that the best conditions were at the center point. The optimized parameters for arsine generation were 2.7 mol L{sup -1} hydrochloric acid and 1.6% (w/v) sodium tetrahydroborate. The optimized conditions to collect arsine in the graphite furnace were a trapping temperature of 250 Degree-Sign C and a collection time of 30 s. The limit of detection was 6.4 ng L{sup -1} and the characteristic mass was 24 pg. Two different systems for acid digestion were used: a digester block with cold finger and a microwave oven. The concentration of arsenic found with the proposed method was compared with that obtained using a detergentless microemulsion and direct graphite furnace determination. The results showed that the factorial design is a simple tool that allowed establishing the appropriate conditions for sample preparation and also helped in evaluating the interaction between the factors investigated. - Highlights: Black-Right-Pointing-Pointer We determined As in gasoline using hydride generation-graphite furnace AAS. Black-Right-Pointing-Pointer We compared three sample preparation procedures. Black-Right-Pointing-Pointer A multivariate approach was used to optimize the conditions. Black

  11. Determination of arsenate in aqueous samples by precipitation of the arsenic(V)-molybdate complex with tetraphenylphosphonium chloride and neutron activation analysis or hydride generation atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Elteren, J.T. van; Haselager, N.G.; Das, H.A. (Netherlands Energy Research Foundation, Petten (Netherlands)); Ligny, C.L. de; Agterdenbos, J. (Rijksuniversiteit Utrecht (Netherlands). Analytisch Chemisch Lab.)

    1991-11-05

    Precipitation of As(V) from aqueous samples is achieved by complexation of As(V) with molybdate followed by formation of an insoluble precipitate with tetraphenylphosphonium chloride (TPP{sup +}Cl{sup -}). The selectivity of the method was studied by investigating the behavior of other arsenic species (As(III), monomethylarsonic acid and dimethyl-arsinic acid) using {sup 73}As-labelled species. It follows that differen-tiation between As(V) and the methylated arsenic acids is excellent, but that some As(III) may precipitate. Combination with selective co-precipitation using dibenzyldithiocarbamate for preliminary As(III) removal yields accurate results when used with neutron activation analysis or hydride generation atomic absorption spectrometry. The competition of phosphate with As(V) for complexation with molybdate limits the use to samples with phosphate concentrations ,6 {mu}g ml{sup -1}. Results for some real water samples are presented. The results of both detection methods are in good agreement. (author). 18 refs.; 3 figs.; 5 tabs.

  12. Determination of arsenate in aqueous samples by precipitation of the arsenic(V)-molybdate complex with tetraphenylphosphonium chloride and neutron activation analysis or hydride generation atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Precipitation of As(V) from aqueous samples is achieved by complexation of As(V) with molybdate followed by formation of an insoluble precipitate with tetraphenylphosphonium chloride (TPP+Cl-). The selectivity of the method was studied by investigating the behavior of other arsenic species [As(III), monomethylarsonic acid and dimethyl-arsinic acid] using 73As-labelled species. It follows that differen-tiation between As(V) and the methylated arsenic acids is excellent, but that some As(III) may precipitate. Combination with selective co-precipitation using dibenzyldithiocarbamate for preliminary As(III) removal yields accurate results when used with neutron activation analysis or hydride generation atomic absorption spectrometry. The competition of phosphate with As(V) for complexation with molybdate limits the use to samples with phosphate concentrations ,6 μg ml-1. Results for some real water samples are presented. The results of both detection methods are in good agreement. (author). 18 refs.; 3 figs.; 5 tabs

  13. Arsenic

    Science.gov (United States)

    ... of countries, including Argentina, Bangladesh, Chile, China, India, Mexico, and the United States of America. Drinking-water, ... ingestion of inorganic arsenic include developmental effects, neurotoxicity, diabetes, pulmonary disease and cardiovascular disease. Arsenic-induced myocardial ...

  14. Arsenic fractionation in agricultural soil using an automated three-step sequential extraction method coupled to hydride generation-atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Highlights: • A fully automated flow-based modified-BCR extraction method was developed to evaluate the extractable As of soil. • The MSFIA–HG-AFS system included an UV photo-oxidation step for organic species degradation. • The accuracy and precision of the proposed method were found satisfactory. • The time analysis can be reduced up to eight times by using the proposed flow-based BCR method. • The labile As (F1 + F2) was <50% of total As in soil samples from As-contaminated-mining zones. - Abstract: A fully automated modified three-step BCR flow-through sequential extraction method was developed for the fractionation of the arsenic (As) content from agricultural soil based on a multi-syringe flow injection analysis (MSFIA) system coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS). Critical parameters that affect the performance of the automated system were optimized by exploiting a multivariate approach using a Doehlert design. The validation of the flow-based modified-BCR method was carried out by comparison with the conventional BCR method. Thus, the total As content was determined in the following three fractions: fraction 1 (F1), the acid-soluble or interchangeable fraction; fraction 2 (F2), the reducible fraction; and fraction 3 (F3), the oxidizable fraction. The limits of detection (LOD) were 4.0, 3.4, and 23.6 μg L−1 for F1, F2, and F3, respectively. A wide working concentration range was obtained for the analysis of each fraction, i.e., 0.013–0.800, 0.011–0.900 and 0.079–1.400 mg L−1 for F1, F2, and F3, respectively. The precision of the automated MSFIA–HG-AFS system, expressed as the relative standard deviation (RSD), was evaluated for a 200 μg L−1 As standard solution, and RSD values between 5 and 8% were achieved for the three BCR fractions. The new modified three-step BCR flow-based sequential extraction method was satisfactorily applied for arsenic fractionation in real agricultural soil samples from

  15. Arsenic fractionation in agricultural soil using an automated three-step sequential extraction method coupled to hydride generation-atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Rosas-Castor, J.M. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León (Mexico); Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Portugal, L.; Ferrer, L. [Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Guzmán-Mar, J.L.; Hernández-Ramírez, A. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León (Mexico); Cerdà, V. [Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Hinojosa-Reyes, L., E-mail: laura.hinojosary@uanl.edu.mx [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León (Mexico)

    2015-05-18

    Highlights: • A fully automated flow-based modified-BCR extraction method was developed to evaluate the extractable As of soil. • The MSFIA–HG-AFS system included an UV photo-oxidation step for organic species degradation. • The accuracy and precision of the proposed method were found satisfactory. • The time analysis can be reduced up to eight times by using the proposed flow-based BCR method. • The labile As (F1 + F2) was <50% of total As in soil samples from As-contaminated-mining zones. - Abstract: A fully automated modified three-step BCR flow-through sequential extraction method was developed for the fractionation of the arsenic (As) content from agricultural soil based on a multi-syringe flow injection analysis (MSFIA) system coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS). Critical parameters that affect the performance of the automated system were optimized by exploiting a multivariate approach using a Doehlert design. The validation of the flow-based modified-BCR method was carried out by comparison with the conventional BCR method. Thus, the total As content was determined in the following three fractions: fraction 1 (F1), the acid-soluble or interchangeable fraction; fraction 2 (F2), the reducible fraction; and fraction 3 (F3), the oxidizable fraction. The limits of detection (LOD) were 4.0, 3.4, and 23.6 μg L{sup −1} for F1, F2, and F3, respectively. A wide working concentration range was obtained for the analysis of each fraction, i.e., 0.013–0.800, 0.011–0.900 and 0.079–1.400 mg L{sup −1} for F1, F2, and F3, respectively. The precision of the automated MSFIA–HG-AFS system, expressed as the relative standard deviation (RSD), was evaluated for a 200 μg L{sup −1} As standard solution, and RSD values between 5 and 8% were achieved for the three BCR fractions. The new modified three-step BCR flow-based sequential extraction method was satisfactorily applied for arsenic fractionation in real agricultural

  16. Determination of Ultra-trace Amounts of Arsenic(III) by Flow Injection Hydride Generation Atomic Absorption Spectrometry with On-line Preconcentration by Coprecipitation with Lanthanum Hydroxide or Hafnium Hydroxide

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Sloth, Jens Jørgen; Hansen, Elo Harald

    1996-01-01

    A time-based flow-injection (FI) procedure for the determination of ultra-trace amounts of inorganic arsenic(III) is described, which combines hydride generation atomic absorption spectrometry (HG-AAS) with on-line preconcentration of the analyte by inorganic coprecipitation-dissolution in a filt......A time-based flow-injection (FI) procedure for the determination of ultra-trace amounts of inorganic arsenic(III) is described, which combines hydride generation atomic absorption spectrometry (HG-AAS) with on-line preconcentration of the analyte by inorganic coprecipitation......-dissolution in a filterless knotted Microline reactor. The sample and coprecipitating agent are mixed on-line and merged with an ammonium buffer solution, which promotes a controllable and quantitative collection of the generated hydroxide on the inner walls of the knotted reactor incorporated into the FI-HG-AAS system....... Subsequently the precipitate is eluted with 1 mol/l hydrochloric acid, allowing ensuing determination of the analyte via hydride generation. The preconcentration of As(III) was tested by coprecipitation with two different inorganic coprecipitating agents namely La(III) and Hf(IV). It was shown that As...

  17. Interstellar Hydrides

    CERN Document Server

    Gerin, Maryvonne; Goicoechea, Javier R

    2016-01-01

    Interstellar hydrides -- that is, molecules containing a single heavy element atom with one or more hydrogen atoms -- were among the first molecules detected outside the solar system. They lie at the root of interstellar chemistry, being among the first species to form in initially-atomic gas, along with molecular hydrogen and its associated ions. Because the chemical pathways leading to the formation of interstellar hydrides are relatively simple, the analysis of the observed abundances is relatively straightforward and provides key information about the environments where hydrides are found. Recent years have seen rapid progress in our understanding of interstellar hydrides, thanks largely to far-IR and submillimeter observations performed with the Herschel Space Observatory. In this review, we will discuss observations of interstellar hydrides, along with the advanced modeling approaches that have been used to interpret them, and the unique information that has thereby been obtained.

  18. 离子色谱-氢化物发生原子荧光法测定尿中形态砷%Determination of arsenic species in urine by ion chromatography-hydride generation-atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    魏静; 梁琼; 刘俊娓

    2013-01-01

    Objective:To develop a method for the determination of arsenic species in urine by Ion chromatography - hydride Generation - atomic fluorescence spectrometry. Methods; The urine sample was filtered by 0.45 μm membrane. Using ( NH4 ) 2 HPO4 as mobile phase to explore the best ion chromatographic separation condition and the atomic fluorescence determination condition. The content of various forms of arsenic was determined by Ion chromatography - hydride Generation - atomic fluorescence spectrometry. Results; This method had good relativity and good precision(2.60% ~4. 30% ). The detection limits of As( Ⅲ), DMA, MMA and As( V ) were 2. 0 (μg/L, 4.0 μg/L,4.0 μg/L,8.0 μg/L, the average recoveries of samples were 90.48% ~ 102.90%. Conclusion; The method had the advantages of convenience, speediness, high sensitivity, less interference and high practical value without chemical pretreatment.%目的:建立离子色谱-氢化物发生原子荧光法测定尿中形态砷的方法.方法:尿样经0.45 μm滤膜过滤,以(NH4)2HPO4为流动相,采用离子色谱-氢化物发生原子荧光联机测定不同形态砷的含量.结果:实验结果相关性好,线性范围宽,精密度RSD为2.60%~4.30%,方法检出限为As(Ⅲ)2.0 μg/L,DMA4.0 μg/L,MMA4.0 μg/L,As(V)8.0 μg/L,该方法所得回收率为90.48% ~ 102.90%.结论:方法简便、快速、无需化学预处理、干扰少、灵敏度高,有较高的实用价值.

  19. Comparative oxidation state specific analysis of arsenic species by high-performance liquid chromatography-inductively coupled-mass spectrometry and hydride generation-cryotrapping-atomic absorption spectrometry

    Science.gov (United States)

    The formation of methylarsonous acid (MAsIII) and dimethylarsinous acid (DMAsIII) in the course of inorganic arsenic (iAs) metabolism plays an important role in the adverse effects of chronic exposure to iAs. High-performance liquid chromatography-inductively coupled plasma-mass ...

  20. Optimize parameters of hydride generation-atomic fluorescence spectrometry for inorganic arsenic determination in grain%氢化物发生-原子荧光法测定粮食中无机砷条件的研究

    Institute of Scientific and Technical Information of China (English)

    杨庆惠

    2012-01-01

    应用氢化物发生—原子荧光分析技术进行粮食中无机砷测定的研究,通过优化酸度、硼氢化钾、载气流量、灯电流以及原子化器高度等分析条件,结果表明,砷浓度在0~30 ng/ml内呈线性关系,相关系数为0.999 9,相对标准偏差为1.6%,检出限为0.054 μg/L,用此方法测定粮食中无机砷,回收率为96.5%~103.5%.该方法简便、快速、灵敏,在实际样品测定中获得到了满意的结果,便于推广应用.%Hydride generation- atomic fluorescence spectrometry was adopted for determine the inorganic arsenic in grain. The experimental parameters such as Ph, KHB4 concentration, flow rate, lamp current and the height of atomizer were optimized. There is linear relation when the arsenic concentration was between 0~30 ng/ml with a correlation coefficient of 0. 999 9. The relative standard deviation was 1. 6%, and the detection limit was 0. 054μg/L. The recovery rate reached to 96. 5%~103. 5%. This method is simple,rapid and sensitive, and got satisfactory results in practicle,it is worth for generalize.

  1. Determination of arsenic releases from glass infusion bottles of drug packaging materials by hydride generation-atomic fluorescence spectrometry%玻璃输液瓶中砷浸出量的原子荧光光谱法测定

    Institute of Scientific and Technical Information of China (English)

    周红娇

    2011-01-01

    目的:建立氢化物发生-原子荧光光谱法HG-AFS测定药包材中玻璃输液瓶的砷浸出量方法.方法:样品液直接用原子荧光光谱法测定,并对HG-AFS工作参数及条件进行优化和选择.结果:标准曲线线性良好,相关系数r=0.999 4,检出限0.064 μg/L,回收率为97.80%,RSD为2.04%.结论:原子荧光光谱法简便、快速准确、灵敏度高.%Objective: To establish a method for determination of arsenic release from Glass Infusion bottles of drug packaging materials by hydride generation-atomic fluorescence spectrometer (HG-AFS). Methods: Sample solutions were directly determined by HG-AFS. Operation parameters of HG-AFS and condition were optimized and selected. Results: A good linearity was obtained (r=0.999 4). The detection limit was 0.064 μg/L. The recovery was 97.80%. RSD was 2.04%.Conclusion: The HG-AFS method is simple and fast with high sensitivity.

  2. Application of Hydride Generation-atomic Fluorescence Spectrometry in Determination of Arsenic in Silicon Dioxide in Food Additives%氢化物-原子荧光法在食品添加剂二氧化硅中砷测定的应用

    Institute of Scientific and Technical Information of China (English)

    吴世银

    2012-01-01

    At present, the food additives are the major factor in food industry, but the arsenic and arsenic compounds in the food additive have very strong biological toxicity. So when testing food additives, we should focus on the arsenic element. This article discussed the silicon dioxide as the food additive in food, as well as the basic condition of arsenic in food and summarized the experiment of using the hydride generation-atomic fluorescence spectrometry to determine the arsenic in silicon dioxide in food additives.%目前构成食品工业主要因素就是食品添加剂,但是食品添加剂中砷及砷的化合物有着很强生物毒性.因此对食品添加剂进行检测时,要将检测重点放在砷元素上.本文对食品中作为食品添加剂的二氧化硅以及食品中砷的基本情况进行简单论述,并对应用氢化物-原子荧光法对食品添加剂二氧化硅中微量砷测定的实验进行总结.

  3. Determination of Inorganic Arsenic in Atmospheric Particles by Hydride Generation-atomic Fluorescence Spectrometry%氢化物发生-原子荧光光谱法测定大气颗粒物中的砷形态

    Institute of Scientific and Technical Information of China (English)

    梁淑轩; 吴虹; 齐学先; 郑璇; 何晓娇

    2011-01-01

    Concentration of atmospheric particles is one of the atmospheric pollution indicators. Heavy metals in the atmospheric particles can risk for human health in both direct and indirect way. Arsenic is one of the higher metal content in them. The inorganic compounds are far more toxic than their organic metabolites. In this paper, the hydride generation atomic fluorescence spectrometric method was employed to the determination of As ( Ⅲ ) and As (V) in the Atmospheric particles. The amount of reducing agent,acid medium and its acidity, carrier gas and shield gas flow rate and observation height of the fluorescence intensity were investigated, and the interference experiment was carried out for concomitant elements. In the best conditions, the detection limit was 0. 34 μg/L, the recovery ranged from 98.18% ~ 102.54%,and the relative standard deviation was about 0.8%. The method was featured by easy operation, fast speed and it has been applied to the analysis of arsenic in the particles with satisfactory results.%采用氢化物发生原子荧光法直接测定不同粒径大气颗粒物中As(Ⅲ)和As(Ⅴ)的含量.研究了还原剂用量、酸介质及其酸度、载气及屏蔽气流量和观测高度等对荧光强度的影响,探讨了共存离子对砷测定的干扰.在选定的最佳条件下,得到检出限为0.34μg/L,方法检出限为0.21μg/g,加标回收率为98.18%~102.54%,相对标准偏差为0.8%左右.用该方法测定大气颗粒物中不同形态的砷,操作简便,快速,灵敏度高.

  4. Determination of Arsenic in Drinking Water by Hydride Atomic Fluorescence Spectrometry%评定氢化物原子荧光法测定生活饮用水中砷的测量不确定度分析

    Institute of Scientific and Technical Information of China (English)

    应绍先; 泽周艳

    2015-01-01

    目的建立氢化物原子荧光法测定生活饮用水中砷的不确定度评定方法,给出不确定度,为提高检测质量提供依据,评定测定结果,找出主要影响因素。方法根据有关生活饮水检验的科学方法和法律法规规定的有关生活饮用水的金属指标GB/T5750,6-2006,应用测量不确定度理论,建立检测方法的数学模型,通过对标准系列稀释过程以及水样的量取等相关过程的讨论分析,讨论每个过程的不确定度分量,并对影响不确定度的因素进行评估。结果对扩展不确定度影响比较大的两大因素分别是标准系列稀释过程和仪器测量精密度过程。讨论与体积相关的四个分项的不确定度,并将标准系列稀释过程作为讨论的重点。结论此方法适用于评估氢化物原子荧光法测定生活饮用水中砷含量的不确定度。%Objective To build the method of evaluation of determination of arsenic in drinking water by Hydride Generation Atomic Fluorescence Spectrometry with uncertainty,give the uncertainty, provide a basis for improving the detection quality, determination of evaluation results,and find out the main influencing factors.Methods The mathematical model established detection method was built used the theory of measurement uncertainty according to the metal indicators related to drinking water drinking water GB/T5750,6-2006 provisions on inspection of scientific methods and laws and regulations,the standard serial dilution process and the amount of water and other related processes was discussed and analysised,uncertainty component of each process was discussed and ef ect of uncertain factors were valuated.Results Two major factors with greater impact on expanded uncertainty were the standard serial dilution process and instrument measurement precision process.The four sub volume and related uncertainty were discuss,and the focus of discussion was the standard serial dilution process.Conclusion This

  5. Determination of arsenic in metallurgical wastewater by hydride generation atomic absorption spectrometry%氢化物-原子吸收光谱法测定冶金企业废水中的砷

    Institute of Scientific and Technical Information of China (English)

    沙保峰; 张小转; 王静; 唐思远; 段文杰; 赵亮

    2012-01-01

    Metallurgical wastewater was digested by the solution of HNO3/HC1O4 (volume ratio 10 : l)and acidified with 6 mol ·L-1 HC1. Resultant digested and acidified wastewater sample was then reduced by potassium iodide (mass fraction 3%), ascorbic acid (1%) and thiourea (1%). Finally, hydride-atomic adsorption spectrometry (HG-AAS) was used to determine arsenic content in the treated wastewater sample. Results indicate that the established method has a detection limit of 0. 297 μg/L, a relative standard deviation of 5. 48% , and a standard addition recovery rate of 93% -108%. Besides, the present method is facile and has good selectivity and sensitivity as well as weak interferences, showing promising application for the determination of micro or trace As in complex wastewater.%采用HNO3/HClO4(体积比10∶1)消解冶金废水样品,经6mol·L-1 HC1溶液酸化后,加入碘化钾(3%)、抗坏血酸(1%)及硫脲(1%)混合溶液进行还原,用氢化物-原子吸收光谱法(HG-AAS)测定了样品中的As含量.结果表明,该方法的检出限为0.297μg/L,相对标准偏差RSD为5.463%,样品加标回收率为93%~108%;其操作方便、选择性好、灵敏度高、干扰少,适合于复杂废水中微量和痕量As的测定.

  6. Speciation analysis of arsenic by selective hydride generation-cryotrapping-atomic fluorescence spectrometry with flame-in-gas-shield atomizer: achieving extremely low detection limits with inexpensive instrumentation.

    Science.gov (United States)

    Musil, Stanislav; Matoušek, Tomáš; Currier, Jenna M; Stýblo, Miroslav; Dědina, Jiří

    2014-10-21

    This work describes the method of a selective hydride generation-cryotrapping (HG-CT) coupled to an extremely sensitive but simple in-house assembled and designed atomic fluorescence spectrometry (AFS) instrument for determination of toxicologically important As species. Here, an advanced flame-in-gas-shield atomizer (FIGS) was interfaced to HG-CT and its performance was compared to a standard miniature diffusion flame (MDF) atomizer. A significant improvement both in sensitivity and baseline noise was found that was reflected in improved (4 times) limits of detection (LODs). The yielded LODs with the FIGS atomizer were 0.44, 0.74, 0.15, 0.17 and 0.67 ng L(-1) for arsenite, total inorganic, mono-, dimethylated As and trimethylarsine oxide, respectively. Moreover, the sensitivities with FIGS and MDF were equal for all As species, allowing for the possibility of single species standardization with arsenate standard for accurate quantification of all other As species. The accuracy of HG-CT-AFS with FIGS was verified by speciation analysis in two samples of bottled drinking water and certified reference materials, NRC CASS-5 (nearshore seawater) and SLRS-5 (river water) that contain traces of methylated As species. As speciation was in agreement with results previously reported and sums of all quantified species corresponded with the certified total As. The feasibility of HG-CT-AFS with FIGS was also demonstrated by the speciation analysis in microsamples of exfoliated bladder epithelial cells isolated from human urine. The results for the sums of trivalent and pentavalent As species corresponded well with the reference results obtained by HG-CT-ICPMS (inductively coupled plasma mass spectrometry).

  7. Determination of arsenic in titanium dioxide by hydride generation atomic fluorescence spectrometry%氢化物发生-原子荧光光谱法测定二氧化钛中砷

    Institute of Scientific and Technical Information of China (English)

    王勇; 王维; 刘元清; 刘林; 龚厚亮

    2016-01-01

    For the detection of arsenic in titanium dioxide ,the sample was usually dissolved with nitric acid‐hydrochloric acid‐hydrofluoric acid system .However ,this pretreatment method had the following prob‐lems :the titanium was easily hydrolyzed;the digestion time was relatively long .In the experiment ,the dissolution method of titanium dioxide sample with sulfuric acid‐ammonium sulfate system was proposed . The problems above were solved .Moreover ,the reaction was mild .Accordingly ,the determination meth‐od of arsenic in titanium dioxide by hydride generation atomic fluorescence spectroscopy (HG‐AFS) was established .The results showed that the mass concentration of arsenic in range of 0.50‐20 μg/L had good linear relationship with the corresponding absorbance .The linear correlation coefficient was 0.999 8 .The detection limit of method was 0.05 μg/L .The interference test results indicated that the coexisting ele‐ments in matrix titanium sample did not interfere with the determination .The proposed method was ap‐plied to the analysis of actual sample ,and the found results were consistent with those obtained by induc‐tively coupled plasma mass spectrometry (ICP‐MS) .The relative standard deviation (RSD ,n=11) was less than 5% .The recoveries of standard addition were between 95% and 101% .%二氧化钛中砷的检测方法中,样品前处理多数采用硝酸‐盐酸‐氢氟酸混酸体系溶解,而采用此法处理样品,会存在钛容易水解且消解时间较长的问题。实验提出了硫酸‐硫酸铵体系溶解二氧化钛样品的方法,不仅解决了上述问题且反应温和,并据此建立了氢化物发生‐原子荧光光谱法(HG‐AFS)测定二氧化钛样品中砷的方法。实验表明,砷的质量浓度在0.50~20μg/L范围内与其对应的吸光度呈线性关系,线性相关系数为0.9998,方法检出限为0.05μg/L。干扰试验表明,基体钛样品中的共存元素均不

  8. Microwave digestion-hydride generation-atomic fluorescence spectrometry determination of arsenic and mercury in imported copper matte%微波消解一氢化物发生原子荧光光谱法测定进口铜锍中砷和汞

    Institute of Scientific and Technical Information of China (English)

    葛钰玮; 索金玲; 王成; 胡晓民

    2011-01-01

    A determination method of arsenic and mercury in imported copper mattc by hydride generation- atomic fluorescence spectrometry (AFS) was established. The copper matte samples were digested in aqua regia and hydrofluoric acid by microwave. Then, the solution was diluted. The thiourea and ascorbic acid were added into digestion solution for prereduction Arsenic and mercury were made to form hydride by adding potassium borohydride. The contents of arsenic and mercury were determined by AFS. The results indicated that the matrix effect of Cu, Fe and S on the determination of elements was not obvious. Under the selected conditions, the detection limits were for arsenic and mercury were 0. 003 9 μg/L and 0. 060 8 μg/L, respectively. The recoveries of standard addition were 95 %-123%, and the relative standard deviations (RSD, n=10) were 0. 56 % and 2. 0% for arsenic and mercury, respectively. The proposed method could be used for the determination of arsenic and mercury in large quantities of copper matte samples.%建立了测定进口铜锍样品中砷、汞含量的氢化物发生原子荧光光谱法.在铜锍试样中加入王水和氢氟酸,经微波消解后稀释,消解液中加入硫脲-抗坏血酸预还原,加硼氢化钾使砷和汞生成硼氢化物,用原子荧光光谱法测定砷和汞含量.铜、铁、硫等对待测元素基体效应不显著.在选定条件下,砷和汞的检出限分别为0.003 9μg/L和0.060 8μg/L,样品的加标回收率在95%~123%之间,砷和汞的相对标准偏差分别为0.56%和2.0%(n=6),方法可用于大批铜锍样品中砷和汞的测定.

  9. 微波消解-氢化物原子荧光光谱法测定粤东地区海产品中砷的研究%Determination of Arsenic in Seafood by Hydride Generation-atomic Fluorescence Spectrometry Combined with Microwave Oven Digestion

    Institute of Scientific and Technical Information of China (English)

    蔡龙飞; 徐春秀; 张应钦; 邱新红

    2011-01-01

    [目的]建立一种测定海产品中微量砷的有效方法.[方法]采用微波消解-氢化物原子荧光光谱法测定了粤东地区海产品中砷的含量.[结果]砷在1.0~50.0μg/L范围内线性关系良好,相关系数为0.995,方法的检出限为0.02107μg/L,相对标准偏差为0.932%.部分海产品的含砷量超过国家标准,其超标原因可能与沿海地区的工业污染有关.[结论]该方法试剂用量少、污染小、简便、快速、准确,适于各类海产品中砷含量的检测.%[Objective] The aim was to establish an effective determination method of arsenic in seafood. [Method] Contents of arsenic in seafood samples from eastern Guangdong area were determined by hydride generation-atomic fluorescence spectrometry combined with microwave oven digestion. [Result] The linear range for detection of arsenic was 1.0- 50.0 μg/L, which showed a good linear relationship,and its correlation coefficient was 0.995. The detection limit and relative standard deviation were 0.021 07 μg/L and 0.932% .respectively. Contents of arsenic in some seafood samples were more than the national standard,which could be caused by industrial pollution in coastal areas. [Conclusion] The method is simple,rapid and accurate,so it is applied to the determination of arsenic in seafood samples.

  10. Speciation analysis of arsenic in groundwater from Inner Mongolia with an emphasis on acid-leachable particulate arsenic

    Energy Technology Data Exchange (ETDEWEB)

    Gong Zhilong [Department of Public Health Sciences, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alta., T6G 2G3 (Canada); Lu Xiufen [Department of Public Health Sciences, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alta., T6G 2G3 (Canada); Watt, Corinna [Department of Public Health Sciences, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alta., T6G 2G3 (Canada); Wen Bei [Department of Public Health Sciences, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alta., T6G 2G3 (Canada); He Bin [Department of Public Health Sciences, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alta., T6G 2G3 (Canada); Mumford, Judy [National Health and Environmental Effects Research Laboratory, Environmental Protection Agency, Human Studies Division, Epidemiology and Biomarkers Branch, Research Triangle Park, NC 27711 (United States); Ning Zhixiong [Ba Men Anti-Epidemic Station, Lin He, Inner Mongolia (China); Xia Yajuan [Inner Mongolia Center for Endemic Disease Control and Research, Huhhot, Inner Mongolia (China); Le, X. Chris [Department of Public Health Sciences, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alta., T6G 2G3 (Canada)]. E-mail: xc.le@ualberta.ca

    2006-01-05

    Arsenic in drinking water affects millions of people around the world. While soluble arsenic is commonly measured, the amount of particulate arsenic in drinking water has often been overlooked. We report here determination of the acid-leachable particulate arsenic and soluble arsenicals in well water from an arsenic-poisoning endemic area in Inner Mongolia, China. Water samples (583) were collected from 120 wells in Ba Men, Inner Mongolia, where well water was the primary drinking water source. Two methods were demonstrated for the determination of soluble arsenic species (primarily inorganic arsenate and arsenite) and total particulate arsenic. The first method used solid phase extraction cartridges and membrane filters to separate arsenic species on-site, followed by analysis of the individual arsenic species eluted from the cartridges and filters. The other method uses liquid chromatography separation with hydride generation atomic fluorescence detection to determine soluble arsenic species. Analysis of acidified water samples using inductively coupled plasma mass spectrometry provided the total arsenic concentration. Arsenic concentrations in water samples from the 120 wells ranged from <1 to {approx}1000 {mu}g L{sup -1}. On average, particulate arsenic accounted for 39 {+-} 38% (median 36%) of the total arsenic. In some wells, particulate arsenic was six times higher than the soluble arsenic concentration. Particulate arsenic can be effectively removed using membrane filtration. The information on particulate and soluble arsenic in water is useful for optimizing treatment options and for understanding the geochemical behavior of arsenic in groundwater.

  11. Determination of arsenic in bag tea samples of health food by hydride generator atomic fluorescence spectrometry%氢化物发生-原子荧光光度法测定保健食品袋泡茶中的总砷

    Institute of Scientific and Technical Information of China (English)

    王正; 张妮娜; 李敏; 沙博郁; 罗仁才

    2011-01-01

    Objective: To establish a method of hydride generator atomic fluorescence spectrometry ( HG - AFS) to determine arsenic in bag tea samples of 20 kinds of health food. Methods: After microwave or wet digestion, the contents of arsenic in twenty bag tea samples were determined by HG - AFS. Results: Linear range for the determination of arsenic was 0 |xg/L ~ 80 μg/L. The linear correlative coefficient for arsenic was 0.9994. The quality of the results was proved by the recovery experiments ( ranging from 92.4% to 109.6% ). The relative standard deviation was 2.5% (n = 11) for arsenic in bag tea samples. The contents of arsenic in bag tea were in the range of 0.10 mg/kg ~0.80 mg/kg. Conclusion: The findings indicate that the proposed method is simple, fast and accurate, which can meet the demand for determining arsenic in bag tea samples of health food.%目的:本文建立了保健食品袋泡茶中总砷的测定方法并测定了20种保健食品袋泡茶中总砷含量.方法:以微波消解和湿消解法处理样品,原子荧光光度法进行测定.结果:本文测定总砷的线性范围为0 μg/L~80μg/L,相关系数为0.9994,方法回收率为92.4%~109.6%,RSD为2.5%.测定的20种保健食品袋泡茶中总砷含量为0.10 mg/kg~0.80 mg/kg.结论:实验表明,本法简单、快速、准确,可以用于保健食品袋泡茶中总砷含量的测定.

  12. Hysteresis in Metal Hydrides.

    Science.gov (United States)

    Flanagan, Ted B., And Others

    1987-01-01

    This paper describes a reproducible process where the irreversibility can be readily evaluated and provides a thermodynamic description of the important phenomenon of hysteresis. A metal hydride is used because hysteresis is observed during the formation and decomposition of the hydride phase. (RH)

  13. Determination of Arsenic and Mercury in Ginseng Seal Pills by Microwave Digestion-Hydride Generation Atomic Florescence Spectrophotometry%微波消解-原子荧光光谱法测定人参海狗丸中的砷·汞含量

    Institute of Scientific and Technical Information of China (English)

    曹旭; 赵瑞霞; 姜兆兴; 李智瑾

    2013-01-01

    [目的]建立微波消解样品、氢化物发生原子荧光光谱法测定人参海狗丸中砷(As)、汞(Hg)含量的方法.[方法]将人参海狗丸样品经硝酸微波消解后,用原子荧光光谱法同时测定As、Hg 2种元素.[结果]试验测得,供试人参海狗丸样品中As、Hg回收率分别为96.2% ~ 109.5%,95.6%~109.1%,RSD <5%.[结论]所建立的方法操作简便、快速、准确、灵敏、重复性好,适用于人参海狗丸中As、Hg的测定.%[ Objective] A method for determination of arsenic(As) , mercury(Hg) in ginseng seal pills by microwave digestion - hydride generation atomic florescence spectrophotometry was established. [ Method] The samples were microwave digested by nitric acid, and were detected by hydride generation atomic florescence spectrophotometry. [ Result] The recovery rate of As, Hg was 96.2% -109.5%, 95.6% -109. 1% , RSD was less 5% . [Conclusion] The method is rapid, accurate and reliable, which can meet the requirements for determination of As and Hg in ginseng seal pills.

  14. Regenerative Hydride Heat Pump

    Science.gov (United States)

    Jones, Jack A.

    1992-01-01

    Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.

  15. Characterization of Arsenic Biotransformation Products from an Open Anaerobic Degradation of Fucus distichus by Hydride Generation Gas Chromatography Atomic Absorption Spectrometry and High Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry

    OpenAIRE

    Abiodun A. Ojo; Onasanya, Amos

    2013-01-01

    This work reports on the isolation and determination of biotransformation products obtained from the organoarsenic compounds that are present in Fucus distichus when it was subjected to an open anaerobic decomposition by using the Hydride Generation Gas Chromatography Atomic Absorption Spectrometry (HG-GC-AAS) and High Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS). The seaweed and filtrate residues obtained from the open anaerobic degradation pro...

  16. Lightweight hydride storage materials

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, G.J.; Guthrie, S.E.; Bauer, W. [Sandia National Labs., Livermore, CA (United States)

    1995-09-01

    The need for lightweight hydrides in vehicular applications has prompted considerable research into the use of magnesium and its alloys. Although this earlier work has provided some improved performance in operating temperature and pressure, substantial improvements are needed before these materials will significantly enhance the performance of an engineered system on a vehicle. We are extending the work of previous investigators on Mg alloys to reduce the operating temperature and hydride heat of formation in light weight materials. Two important results will be discussed in this paper: (1) a promising new alloy hydride was found which has better pressure-temperature characteristics than any previous Mg alloy and, (2) a new fabrication process for existing Mg alloys was developed and demonstrated. The new alloy hydride is composed of magnesium, aluminum and nickel. It has an equilibrium hydrogen overpressure of 1.3 atm. at 200{degrees}C and a storage capacity between 3 and 4 wt.% hydrogen. A hydrogen release rate of approximately 5 x 10{sup -4} moles-H{sub 2}/gm-min was measured at 200{degrees}C. The hydride heat of formation was found to be 13.5 - 14 kcal/mole-H{sub 2}, somewhat lower than Mg{sub 2}Ni. The new fabrication method takes advantage of the high vapor transport of magnesium. It was found that Mg{sub 2}Ni produced by our low temperature process was better than conventional materials because it was single phase (no Mg phase) and could be fabricated with very small particle sizes. Hydride measurements on this material showed faster kinetic response than conventional material. The technique could potentially be applied to in-situ hydride bed fabrication with improved packing density, release kinetics, thermal properties and mechanical stability.

  17. Conference 'Chemistry of hydrides' Proceedings

    International Nuclear Information System (INIS)

    This collection of thesis of conference of Chemistry hydrides presents the results of investigations concerning of base questions of chemistry of nonorganic hydrides, including synthesis questions, studying of physical and chemical properties, thermodynamics, analytical chemistry, investigation of structure, equilibriums in the systems of metal-hydrogen, behaviour of nonorganic hydrides in non-water mediums and applying investigations in the chemistry area and technology of nonorganic hydrides

  18. Arsenic occurrence in New Hampshire drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Peters, S.C.; Blum, J.D.; Klaue, B. [Dartmouth Coll., Hanover, NH (United States). Dept. of Earth Sciences; Karagas, M.R. [Dartmouth Medical School, Hanover, NH (United States). Dept. of Community and Family Medicine

    1999-05-01

    Arsenic concentrations were measured in 992 drinking water samples collected from New Hampshire households using online hydride generation ICP-MS. These randomly selected household water samples contain much less arsenic than those voluntarily submitted for analysis to the New Hampshire Department of Environmental Services (NHDES). Extrapolation of the voluntarily submitted sample set to all New Hampshire residents significantly overestimates arsenic exposure. In randomly selected households, concentrations ranged from <0.0003 to 180 {micro}g/L, with water from domestic wells containing significantly more arsenic than water from municipal sources. Water samples from drilled bedrock wells had the highest arsenic concentrations, while samples from surficial wells had the lowest arsenic concentrations. The authors suggest that much of the groundwater arsenic in New Hampshire is derived from weathering of bedrock materials and not from anthropogenic contamination. The spatial distribution of elevated arsenic concentrations correlates with Late-Devonian Concord-type granitic bedrock. Field observations in the region exhibiting the highest groundwater arsenic concentrations revealed abundant pegmatite dikes associated with nearby granites. Analysis of rock digests indicates arsenic concentrations up to 60 mg/kg in pegmatites, with much lower values in surrounding schists and granites. Weak acid leaches show that approximately half of the total arsenic in the pegmatites is labile and therefore can be mobilized during rock-water interaction.

  19. Speciation of arsenic in environmental waters

    International Nuclear Information System (INIS)

    A system for speciation of arsenic in environmental waters by selective hydride formation and on-line AAS is described. Starting from literature data, the separation scheme and the necessary apparatus are outlined. Preliminary practical experience then leads to the formulation of further improvements and accompanying testing experiments. (author). 51 refs, 7 figs, 1 tab

  20. Multisyringe flow injection lab-on-valve systems coupled to hydride generation atomic fluorescence spectrometry for on-line bead-injection preconcentration and determination of total inorganic arsenic in environmental waters

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald;

    In this work, the third generation of flow injection analysis, that is, the so-called micro-Lab-on-Valve (LOV) approach, is hyphenated for the first time to atomic fluorescence spectrometry (AFS) for the separation, preconcentration and monitoring of hydride forming elements. A multisyringe flowing...... before loading into the multisyringe flow system. The flow system facilitates on-column reduction with no need for application of programmable stopped-flow. Yet, the high electrolyte concentrations and extreme pH conditions for elution prevents the sorbent to be re-used, so that maximum benefit can...

  1. 氢化物发生-原子荧光光谱法同时测定红土镍矿中砷锑铋%Determination of arsenic,antimony and bismuth in laterite nickel ore by hydride generation-atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    何飞顶; 李华昌; 袁玉霞

    2011-01-01

    The content of arsenic,antimony and bismuth in laterite nickel ore was determined with hydride generation-atomic fluorescence spectrometry( HG-AFS). The influencing factors were discussed in detail. The aqua regia bath was adopted for reducing the volatile loss of elements to be tested,while the mixed solution of thiourea and ascorbic acid was used as masking reagent to eliminate the impact of interfering elements. The detection limit of method was between 0. 10-0. 25 ng/mL. The arsenic,antimony and bisnmuth in laterite nickel ore was analyzed with the recovery of 91%-113% and relative standard deviation( RSD) of 1. 9 %-7. 6 %.%采用氢化物发生-原子荧光光谱(HG-AFS)法测定红土镍矿中砷、锑、铋含量,并对影响其光谱测量的各种因素进行了较为详细的探讨.实验中,以王水水浴法溶解样品降低待测元素的挥发损失,以硫脲和抗坏血酸混合溶液为掩蔽剂来消除干扰元素的影响.方法的检出限在0.10~0.25 ng/mL之间;对红土镍矿样品中的砷、锑、铋进行分析,其回收率在91%~113%之间,相对标准偏差(RSD)为1.9%~7.6%.

  2. Arsenic species excretion after dimercaptopropanesulfonic acid (DMPS) treatment of an acute arsenic trioxide poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich-Ramm, R. [Ordinariat fuer Arbeitsmedizin der Universitaet Hamburg und Zentralinstitut fuer Arbeitsmedizin, Hamburg (Germany); Schaller, K.H.; Angerer, J. [Institut und Poliklinik fuer Arbeits-, Sozial- und Umweltmedizin der Universitaet Erlangen-Nuernberg, Schillerstr. 25, 91054 Erlangen (Germany); Horn, J. [Medizinische Klinik II, Toxikologische-internistische Intensivstation, Klinikum Nuernberg, Nuernberg (Germany)

    2003-02-01

    We studied the urinary excretion of the different arsenic species in urine samples from a young man who tried to commit suicide by ingesting about 0.6 g arsenic trioxide. He received immediate therapy with dimercaptopropanesulfonic acid (DMPS) after his delivery into the hospital. We assessed urinary arsenite (inorganic trivalent arsenic), arsenate (inorganic pentavalent arsenic), pentavalent dimethylarsinic acid (DMA) and pentavalent monomethylarsonic acid (MMA) in urine with ion-exchange chromatography and on-line hydride-technique atomic absorption spectrometry. The predominant amount of the excreted arsenic was unchanged trivalent inorganic arsenic (37.4%), followed by pentavalent inorganic arsenic (2.6%), MMA (2.1%), DMA (0.2%) and one unidentified arsenic species (0.7%, if calculated as DMA). In the first urine voiding in the clinic, the total arsenic concentration was 215 mg/l, which fell 1000-fold after 8 days of DMPS therapy. A most striking finding was the almost complete inhibition of the second methylation step in arsenic metabolism. As mechanisms for the reduced methylation efficiency, the saturation of the enzymatic process of arsenic methylation, the high dosage of antidote DMPS, which might inhibit the activity of the methyl transferases, and analytical reasons are discussed. The high dosage of DMPS is the most likely explanation. The patient left the hospital after a 12-day treatment with antidote. (orig.)

  3. 氢化物原子荧光光谱法测定铜精矿及铜矿石中砷的研究%Determination of arsenic in copper concentrate and copper ore by hydride atomic fluorescent spectrometry

    Institute of Scientific and Technical Information of China (English)

    胡郁

    2012-01-01

    By removing the disturbance of determined arsenic with the atomic fluorescent spectrometry,which by copper ion and other metal ion in copper concentrate and copper ore,to build a suited dissolution method,and to choose the optimization condition,to overcome the shortage of general atomic fluorescent spectrometry dissolved the sample.The detection limit of the method is 1μg/g.This method is applied to three national standard samples(level one) to detect the content of arsenic.The detected values and recommended ones are consistent.Therefore,the method is feasible to test the content of arsenic in high copper concentrate samples.%通过对铜精矿及铜矿石中大量铜离子等多种金属离子对原子荧光光谱法测定砷干扰的消除,建立一种适合的溶样方法,选择了最佳的分析条件,克服了普通原子荧光法溶解样品的不足,本方法测定砷的检出限为1μg/g。本方法测定了3个国家一级标准物质中砷的含量,测定值与推荐值吻合,确定方法适合铜含量比较高的样品中砷含量的测定。

  4. Method development for arsenic analysis by modification in spectrophotometric technique

    Directory of Open Access Journals (Sweden)

    M. A. Tahir

    2012-01-01

    Full Text Available Arsenic is a non-metallic constituent, present naturally in groundwater due to some minerals and rocks. Arsenic is not geologically uncommon and occurs in natural water as arsenate and arsenite. Additionally, arsenic may occur from industrial discharges or insecticide application. World Health Organization (WHO and Pakistan Standard Quality Control Authority have recommended a permissible limit of 10 ppb for arsenic in drinking water. Arsenic at lower concentrations can be determined in water by using high tech instruments like the Atomic Absorption Spectrometer (hydride generation. Because arsenic concentration at low limits of 1 ppb can not be determined easily with simple spectrophotometric technique, the spectrophotometric technique using silver diethyldithiocarbamate was modified to achieve better results, up to the extent of 1 ppb arsenic concentration.

  5. Air and metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

    Lampinen, M.; Noponen, T. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Applied Thermodynamics

    1998-12-31

    The main goal of the air and metal hydride battery project was to enhance the performance and manufacturing technology of both electrodes to such a degree that an air-metal hydride battery could become a commercially and technically competitive power source for electric vehicles. By the end of the project it was possible to demonstrate the very first prototype of the air-metal hydride battery at EV scale, achieving all the required design parameters. (orig.)

  6. The use of L-ascorbic acid in speciation of arsenic compounds in drinking water

    Directory of Open Access Journals (Sweden)

    Marjanović Nikola J.

    2009-01-01

    Full Text Available Arsenic speciation, besides total arsenic content determination, is very important in analysis of water, foodstuffs, and environmental samples, because of varying degrees of toxicity of different species. For such purpose hydride generation atomic absorption spectrometry can be used based on the generation of certain types of hydride, depending on the pH value and pretreatment in different reaction media. In this study, we have investigated the effect of L-ascorbic acid as the reaction medium as well as the pre-reducing agent in speciation of arsenic by hydride generation-atomic absorption spectrometry in order to determine monomethyl arsonic acid (MMA in the presence of inorganic forms of arsenic.

  7. A New Method for Determination of Arsenic and Mercury in Copper Concentrates: By High pressure airproof Microwave Digestion,Sequential Injection,Hydride Generation,and Atomic Fluorescence Spectrometry%一种检测铜精矿中砷和汞含量的新方法——高压密封微波消解-顺序注射-氢化物发生-原子荧光光谱法

    Institute of Scientific and Technical Information of China (English)

    苏明跃; 杨丽飞; 郭芬

    2011-01-01

    利用高压密封微波消解和顺序注射-氢化物发生-原子荧光光谱两项技术建立了检测铜精矿中砷、汞含量的新方法,并通过试验确定了适宜的检测条件.研究结果表明:本方法对砷的检出限为0.02μg/L,对汞的检出限为0.05μg/L;检测铜精矿中砷、汞的含量时,砷、汞的回收率分别为94.3%~107.0%和91.0%~102.0%,检测结果相对标准偏差分别在0.93%~1.97%之间和3.11%~8.07%之间,并且检测结果与认定值和国家标准方法测定值一致.%A new method for the determinations of arsenic content and mercury content in copper concentrates was founded by adopting two processes of high pressure-airproof microwave digestion and the sequential injection-hydride generation -atomic fluorescence spectrometry. Through tests, the optimum conditions for detection were determined. The tests resuits indicated that the detection limit of arsenic was 0.02 μg/L and the detection limit of mercury was 0.05 μg/L by this method. While detecting arsenic and mercury content in copper concentrate, it is found that the arsenic and mercury recovery rates reached 94.3% ~ 107.0% and 91.0% ~ 102.0% respectively with relative standard of deviation between 0.93% ~1.97% for arsenic and 3.11% ~ 8.07% for mercury. Also, these detecting results are in good agreement with the certified values and the values by the national standard method.

  8. Determination of arsenic in antimony ingot and antimony trioxide by hydride generation-atomic fluorescence spectrometry%氢化物发生-原子荧光光谱法测定锑锭及三氧化二锑中的砷

    Institute of Scientific and Technical Information of China (English)

    钱光敏; 赵国杏

    2012-01-01

    The antimony slab and antimonous oxide samples were dissolved by sulfuric acid and hydrochloric acid, respectively. The Sb3+ in solution was precipitated with sodium hydroxide to separate trace arsenic from matrix antimony. The thiourea-ascorbic acid was added to reduce As5+ to As3+. Then, the arsenic in antimony slab and antimonous oxide was determined by atomic fluorescence spec-trometry. The hydride generation conditions were investigated: the concentration of reducing agent potassium borohydride was 25 g/L, the determination medium was 20% (V/V) hydrochloric acid, and the dosage of thiourea - ascorbic acid solution was 5 mL. The interference test of coexisting elements showed that, the interference of residual antimony in solution after precipitation could be fully eliminated by adding 1 mL of tartaric acid solution. Other impurity elements in sample did not interfere with the determination of arsenic after adding thiourea-ascorbic acid solution. The detection limit of method was 0. 156 ng/mL. The antimony slab and antimonous oxide samples were analyzed by the proposed method, and the relative standard deviation (RSD) was 0. 95%-1.2%. The determination results were consistent with those obtained by national standard methods.%采用硫酸溶解锑锭样品,盐酸溶解三氧化二锑样品,用氢氧化钠溶液使Sb3+沉淀从而使基体锑与微量砷分离,通过加入硫脲-抗坏血酸将As5+还原成As3+,然后在原子荧光仪上测定锑锭及三氧化二锑中的砷.对氢化物发生条件进行考察,确定还原剂硼氢化钾的浓度为25 g/L、测定介质为20%(V/V)盐酸、硫脲-抗坏血酸溶液用量为5 mL.共存元素干扰试验表明,沉淀后溶液中残留少量锑的干扰在加入1 mL酒石酸溶液后可以完全消除,而样品中其他杂质元素在加入硫脲-抗坏血酸溶液后不干扰砷的测定.方法的检出限为0.156 ng/mL.对锑锭及三氧化二锑样品进行分析,相对标准偏差为0.95%~1.2%,测定

  9. Arsenic ototoxicity

    Institute of Scientific and Technical Information of China (English)

    Gulin Gokçen Kesici

    2016-01-01

    High levels of arsenic are found in many parts of the world and more than 100 million people may have been exposed to it. There is growing evidence to indicate that arsenic has a deleterious effect on the auditory system. This paper provides the general information of arsenic and its ototoxic effects.

  10. Erbium hydride decomposition kinetics.

    Energy Technology Data Exchange (ETDEWEB)

    Ferrizz, Robert Matthew

    2006-11-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

  11. Metal hydride air conditioner

    Institute of Scientific and Technical Information of China (English)

    YANG; Ke; DU; Ping; LU; Man-qi

    2005-01-01

    The relationship among the hydrogen storage properties, cycling characteristics and thermal parameters of the metal hydride air conditioning systems was investigated. Based on a new alloy selection model, three pairs of hydrogen storage alloys, LaNi4.4 Mn0.26 Al0.34 / La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1, LaNi4.61Mn0. 26 Al0.13/La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1 and LaNi4.61 Mn0.26 Al0.13/La0.6 Y0.4 Ni4.8 Mn0. 2, were selected as the working materials for the metal hydride air conditioning system. Studies on the factors affecting the COP of the system showed that higher COP and available hydrogen content need the proper operating temperature and cycling time,large hydrogen storage capacity, flat plateau and small hysterisis of hydrogen alloys, proper original input hydrogen content and mass ratio of the pair of alloys. It also needs small conditioning system was established by using LaNi4.61 Mn0.26 Al0. 13/La0.6 Y0.4 Ni4.8 Mn0.2 alloys as the working materials, which showed that under the operating temperature of 180℃/40℃, a low temperature of 13℃ was reached, with COP =0.38 and Wnet =0.09 kW/kg.

  12. Hydride development for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, G.J.; Guthrie, S.E.; Bauer, W.; Yang, N.Y.C. [Sandia National Lab., Livermore, CA (United States); Sandrock, G. [SunaTech, Inc., Ringwood, NJ (United States)

    1996-10-01

    The purpose of this project is to develop and demonstrate improved hydride materials for hydrogen storage. The work currently is organized into four tasks: hydride development, bed fabrication, materials support for engineering systems, and IEA Annex 12 activities. At the present time, hydride development is focused on Mg alloys. These materials generally have higher weight densities for storing hydrogen than rare earth or transition metal alloys, but suffer from high operating temperatures, slow kinetic behavior and material stability. The authors approach is to study bulk alloy additions which increase equilibrium overpressure, in combination with stable surface alloy modification and particle size control to improve kinetic properties. This work attempts to build on the considerable previous research in this area, but examines specific alloy systems in greater detail, with attention to known phase properties and structures. The authors have found that specific phases can be produced which have significantly improved hydride properties compared to previous studies.

  13. Geoneutrino and Hydridic Earth model

    CERN Document Server

    Bezrukov, Leonid

    2013-01-01

    Uranium, Thorium and Potassium-40 abundances in the Earth were calculated in the frame of Hydridic Earth model. Terrestrial heat producton from U, Th and K40 decays was calculated also. We must admit the existance of Earth expansion process to understand the obtained large value of terrestrial heat producton. The geoneutrino detector with volume more than 5 kT (LENA type) must be constructed to definitely separate between Bulk Silicat Earth model and Hydridic Earth model.

  14. Digestion and preparation methods of different samples determine elements produced hydride generation

    International Nuclear Information System (INIS)

    The aim of this work is to explain the principle of hydride generation technique, which is another technique of atomic absorption spectrometry, in addition to flame and graphite techniques. This technique is used to determine some metals and nonmetals (Se, Sn, Te, Sb, Bi, AS, Hg ) which produce volatile compounds in their reactions. The study focuses on the analytical capabilities of the hydride generation technique, the principle of hydride generation process, the interferences that affect the analysis process (spectra interference, chemical interference, kinetic interference, oxidation state interference, gas layer interference) and the methods to overcome these interferences. The working steps of the technique have been reported, finally some experimental work has been performed on different kind of samples such as: waste, tripolyphosphate, volcanic rock and phosphogypsum to determine mercury and blood sample to determine arsenic. (Authors)

  15. Physics of hydride fueled PWR

    Science.gov (United States)

    Ganda, Francesco

    The first part of the work presents the neutronic results of a detailed and comprehensive study of the feasibility of using hydride fuel in pressurized water reactors (PWR). The primary hydride fuel examined is U-ZrH1.6 having 45w/o uranium: two acceptable design approaches were identified: (1) use of erbium as a burnable poison; (2) replacement of a fraction of the ZrH1.6 by thorium hydride along with addition of some IFBA. The replacement of 25 v/o of ZrH 1.6 by ThH2 along with use of IFBA was identified as the preferred design approach as it gives a slight cycle length gain whereas use of erbium burnable poison results in a cycle length penalty. The feasibility of a single recycling plutonium in PWR in the form of U-PuH2-ZrH1.6 has also been assessed. This fuel was found superior to MOX in terms of the TRU fractional transmutation---53% for U-PuH2-ZrH1.6 versus 29% for MOX---and proliferation resistance. A thorough investigation of physics characteristics of hydride fuels has been performed to understand the reasons of the trends in the reactivity coefficients. The second part of this work assessed the feasibility of multi-recycling plutonium in PWR using hydride fuel. It was found that the fertile-free hydride fuel PuH2-ZrH1.6, enables multi-recycling of Pu in PWR an unlimited number of times. This unique feature of hydride fuels is due to the incorporation of a significant fraction of the hydrogen moderator in the fuel, thereby mitigating the effect of spectrum hardening due to coolant voiding accidents. An equivalent oxide fuel PuO2-ZrO2 was investigated as well and found to enable up to 10 recycles. The feasibility of recycling Pu and all the TRU using hydride fuels were investigated as well. It was found that hydride fuels allow recycling of Pu+Np at least 6 times. If it was desired to recycle all the TRU in PWR using hydrides, the number of possible recycles is limited to 3; the limit is imposed by positive large void reactivity feedback.

  16. 兰州市城区垃圾存储场渗透污水中砷的氢化物发生-原子荧光光谱法快速测定%Rapid Determination of Arsenic in Infiltration Wastewater of Lanzhou City Garbage Storage Field by Hydride Generation-Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    杨贵生; 祝建国; 毛振才

    2016-01-01

    In this paper HNO3-HClO4 was used to digeste the sample, thiourea and chloric acid were added to reduce the sample in hydrochloric acid solution, and arsenic in the pretreated sample was analyzed using hydride-atomic absorption spectrometry. The method had been applied to the city rubbish infiltration wastewater in the sewage storage site of Lanzhou. The recoveries were 98. 3% ~104%, the relative standard deviation were 1. 2% ~3. 2%, and the detection limit of method was 0. 35 μg/L, the Linear regression equation was: IF=15. 962 × C+0. 423 and the correlation coefficient was 0. 999 8. It is confirmed by testing that the method is simple, rapid, accurate and reliable, and has a wide measurable range, it is an effective detection method for the directly determination of urban sewage, and is able to provide a scientific basis for the evaluation of garbage storage site of Lanzhou city on the degree of impact of the environment and the governance.%采用硝酸-高氯酸消解,在盐酸介质中加入硫脲、抗坏血酸还原.应用氢化物发生-原子荧光光谱法对兰州市城区垃圾存储场地下渗透污水中的砷进行了测定.其方法回收率在98.3%~104%之间,相对标准偏差在1.2%~3.2%之间,方法检出限为0.35μg/L,线性回归方程为:IF=15.962×C+0.423,相关系数为0.9998.经试验证实,方法简便快速、准确可靠、可测范围宽,是一种直接测定城市污水的有效检测方法.为兰州市城区垃圾存储场地对环境的影响程度、评估治理提供了科学依据.

  17. A New Reducing Regent: Dichloroindium Hydride

    Institute of Scientific and Technical Information of China (English)

    A. BABA; I. SHIBATA; N. HAYASHI

    2005-01-01

    @@ 1Introduction Among the hydride derivatives of group 13 elements, various types of aluminum hydrides and boron hydrides have been employed as powerful reduction tools. Indium hydrides have not received much attention,whereas the synthesis of indium trihydride (InH3) was reported several decades ago[1]. There have been no precedents for monometallic indium hydrides having practical reactivity, while activated hydrides such as an ate complex LiPhn InH4-n (n = 0- 2) and phosphine-coordinated indium hydrides readily reduce carbonyl compounds. In view of this background, we focused on the development of dichloroindium hydrides (Cl2InH) as novel reducing agents that bear characteristic features in both ionic and radical reactions.

  18. Hydride Olefin complexes of tantalum and niobium

    NARCIS (Netherlands)

    Klazinga, Aan Hendrik

    1979-01-01

    This thesis describes investigations on low-valent tantalum and niobium hydride and alkyl complexes, particularly the dicyclopentadienyl tantalum hydride olefin complexes Cp2Ta(H)L (L=olefin). ... Zie: Summary

  19. Luminescent properties of aluminum hydride

    Energy Technology Data Exchange (ETDEWEB)

    Baraban, A.P.; Gabis, I.E.; Dmitriev, V.A. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Dobrotvorskii, M.A., E-mail: mstislavd@gmail.com [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Kuznetsov, V.G. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Matveeva, O.P. [National Mineral Resources University, Saint Petersburg 199106 (Russian Federation); Titov, S.A. [Petersburg State University of Railway Transport, Saint-Petersburg 190031 (Russian Federation); Voyt, A.P.; Elets, D.I. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation)

    2015-10-15

    We studied cathodoluminescence and photoluminescence of α-AlH{sub 3}– a likely candidate for use as possible hydrogen carrier in hydrogen-fueled vehicles. Luminescence properties of original α-AlH{sub 3} and α-AlH{sub 3} irradiated with ultraviolet were compared. The latter procedure leads to activation of thermal decomposition of α-AlH{sub 3} and thus has a practical implementation. We showed that the original and UV-modified aluminum hydride contain luminescence centers ‐ structural defects of the same type, presumably hydrogen vacancies, characterized by a single set of characteristic bands of radiation. The observed luminescence is the result of radiative intracenter relaxation of the luminescence center (hydrogen vacancy) excited by electrons or photons, and its intensity is defined by the concentration of vacancies, and the area of their possible excitation. UV-activation of the dehydrogenation process of aluminum hydride leads to changes in the spatial distribution of the luminescence centers. For short times of exposure their concentration increases mainly in the surface regions of the crystals. At high exposures, this process extends to the bulk of the aluminum hydride and ends with a decrease in concentration of luminescence centers in the surface region. - Highlights: • Aluminum hydride contains hydrogen vacancies which serve as luminescence centers. • The luminescence is the result of radiative relaxation of excited centers. • Hydride UV-irradiation alters distribution and concentration of luminescence centers.

  20. Arsenic poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Schoolmeester, W.L.; White, D.R.

    1980-02-01

    Arsenic poisoning continues to require awareness of its diverse clinical manifestations. Industry is the major source of arsenic exposure. Although epidemiologic studies strongly contend that arsenic is carcinogenic, there are little supportive research data. Arsenic poisoning, both acute and chronic, is often overlooked initially in the evaluation of the patient with multisystem disease, but once it is suspected, many accurate methods are available to quantitate the amount and duration of exposure. Treatment with dimercaprol remains the mainstay of therapy, and early treatment is necessary to prevent irreversible complications.

  1. Hydrogen, lithium, and lithium hydride production

    Science.gov (United States)

    Brown, Sam W; Spencer, Larry S; Phillips, Michael R; Powell, G. Louis; Campbell, Peggy J

    2014-03-25

    A method of producing high purity lithium metal is provided, where gaseous-phase lithium metal is extracted from lithium hydride and condensed to form solid high purity lithium metal. The high purity lithium metal may be hydrided to provide high purity lithium hydride.

  2. Determination of arsenic in air particulates and diesel exhaust particulates by spectrophotometry

    Institute of Scientific and Technical Information of China (English)

    S. M. Talebi; M. Abedi

    2005-01-01

    A method was developed for the determination of trace arsenic by spectrophotometry. The proposed method is rapid, simple,and inexpensive. This method can be used for sensitive determination of trace arsenic in environmental samples and especially in air particulates. The results obtained by this method as a proposed method were compared with those obtained by hydride generation atomic absorption spectrometry as a popular reported method for the determination of arsenic and an excellent agreement was found between them. The method was also used for determination of arsenic associated with airborne particulate matter and diesel exhaust particulates.The results showed that considerable amount of arsenic are associated with diesel engine particulates. The variation in concentration of arsenic was also investigated. The atmospheric concentration of arsenic was different in different sampling stations was dependent to the traffic density.

  3. Thermomechanical properties of hafnium hydride

    International Nuclear Information System (INIS)

    Fine bulk samples of delta-phase Hf hydride with various hydrogen contents (CH) ranging from 1.62 to 1.72 in the atomic ratio (H/Hf) were prepared, and their thermomechanical properties were characterized. At room temperature, the sound velocity and Vickers hardness were measured. The elastic modulus was calculated from the measured sound velocity. In the temperature range from room temperature to 673 K, the thermal expansion was measured by using a dilatometer, and the linear thermal expansion coefficient was calculated. Empirical equations describing the thermomechanical properties of Hf hydride as a function of CH were proposed. (author)

  4. Arsenic poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Low, D.G.

    1971-01-01

    The use of arsenic in ant poisons, herbicides, and insecticides affords the necessary contact with the poison by pets. Treatment was discussed in relation to two circumstances: very early poisoning in which the owner has observed ingestion of the arsenic, and when the signs of the poisoning are evident. Treatment for early ingestion involves emptying the stomach before the arsenic can pass in quantity into the intestine. This is followed with a 1% solution of sodium bicarbonate, with the administering of 3 to 6 mg of apomorphine. When signs of arsenic toxicity are already advanced, there is little advantage to be gained by either gastric lavage or administration of an emetic. The treatment then consists of the intramuscular administration of dimercaprol (BAL) at a dosage of 3 mg/lb of body weight three times a day until recovery. This is the specific antidote for arsenic. 1 reference.

  5. Clinical manifestations and arsenic methylation after a rare subacute arsenic poisoning accident.

    Science.gov (United States)

    Xu, Yuanyuan; Wang, Yi; Zheng, Quanmei; Li, Bing; Li, Xin; Jin, Yaping; Lv, Xiuqiang; Qu, Guang; Sun, Guifan

    2008-06-01

    One hundred and four workers ingested excessive levels of arsenic in an accident caused by leakage of pipeline in a copper-smelting factory. Clinical examinations were performed by physicians in a local hospital. Excreted urinary arsenic species were determined by cold trap hydride generation atomic absorption spectrometry. In the initial toxic phase, gastrointestinal symptoms were predominant (83 people, 79.8%). Most patients showed leucopenia (72 people, 69.2%), and increased serum alanine aminotransferase (84 people, 80.8%) and aspartate aminotransferase (58 people, 55.8%). Thirty-five patients (33.6%) had elevated red blood cells in urine. After 17 days of admission, many subjects (45 people, 43.3%) developed peripheral neuropathy and 25 of these 45 patients (24.0%) showed a decrease in motor and sensory nerve conduction velocity. In the comparison of urinary arsenic metabolites among subacute arsenic-poisoned, chronic high arsenic-exposed and control subjects, we found that subacute arsenic-poisoned patients had significantly elevated proportions of urinary inorganic arsenic (iAs) and methylarsonic acid (MMA) but reduced proportion of urinary dimethylarsinic acid (DMA) compared with chronic high arsenic-exposed and control subjects. Chronic exposed subjects excreted higher proportions of iAs and MMA but lower proportions of DMA in urine compared with control subjects. These results suggest that gastrointestinal symptoms, leucopenia, and hepatic and urinary injury are predominant in the initial phase of subacute arsenic poisoning. Peripheral neuropathy is the most frequent manifestation after the initial phase. The biomethylation of arsenic decreases in a dose rate-dependent manner.

  6. Significantly increased risk of carotid atherosclerosis with arsenic exposure and polymorphisms in arsenic metabolism genes

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Yi-Chen [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, 250 Wusing St., Taipei 11031, Taiwan (China); Lien, Li-Ming [Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Medicine, Taipei Medical University, Taipei, Taiwan (China); Department of Neurology, Shin Kong WHS Memorial Hospital, Taipei, Taiwan (China); Chung, Wen-Ting [Department of Neurology, Wanfang Hospital, Taipei Medical University, Taipei, Taiwan (China); Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan (China); Hsieh, Fang-I; Hsieh, Pei-Fan [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, 250 Wusing St., Taipei 11031, Taiwan (China); Wu, Meei-Maan [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, 250 Wusing St., Taipei 11031, Taiwan (China); Graduate Institute of Basic Medicine, College of Medicine, Fu-Jen Catholic University, Taipei, Taiwan (China); Tseng, Hung-Pin [Department of Neurology, Lotung Poh-Ai Hospital, I-Lan, Taiwan (China); Chiou, Hung-Yi, E-mail: hychiou@tmu.edu.tw [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, 250 Wusing St., Taipei 11031, Taiwan (China); Chen, Chien-Jen [Genomics Research Center, Academia Sinica, Taipei, Taiwan (China)

    2011-08-15

    Individual susceptibility to arsenic-induced carotid atherosclerosis might be associated with genetic variations in arsenic metabolism. The purpose of this study is to explore the interaction effect on risk of carotid atherosclerosis between arsenic exposure and risk genotypes of purine nucleoside phosphorylase (PNP), arsenic (+3) methyltransferase (As3MT), and glutathione S-transferase omega 1 (GSTO1) and omega 2 (GSTO2). A community-based case-control study was conducted in northeastern Taiwan to investigate the arsenic metabolic-related genetic susceptibility to carotid atherosclerosis. In total, 863 subjects, who had been genotyped and for whom the severity of carotid atherosclerosis had been determined, were included in the present study. Individual well water was collected and arsenic concentration determined using hydride generation combined with flame atomic absorption spectrometry. The result showed that a significant dose-response trend (P=0.04) of carotid atherosclerosis risk associated with increasing arsenic concentration. Non-significant association between genetic polymorphisms of PNP Gly51Ser, Pro57Pro, As3MT Met287Thr, GSTO1 Ala140Asp, and GSTO2 A-183G and the risk for development of carotid atherosclerosis were observed. However, the significant interaction effect on carotid atherosclerosis risk was found for arsenic exposure (>50 {mu}g/l) and the haplotypes of PNP (p=0.0115). A marked elevated risk of carotid atherosclerosis was observed in subjects with arsenic exposure of >50 {mu}g/l in drinking water and those who carried the PNP A-T haplotype and at least either of the As3MT risk polymorphism or GSTO risk haplotypes (OR, 6.43; 95% CI, 1.79-23.19). In conclusion, arsenic metabolic genes, PNP, As3MT, and GSTO, may exacerbate the formation of atherosclerosis in individuals with high levels of arsenic concentration in well water (>50 {mu}g/l). - Highlights: {yields}Arsenic metabolic genes might be associated with carotid atherosclerosis. {yields

  7. Simultaneous determination of arsenic and mercury of sea-water aquiculture base environment medium by flow injection Hydride Generation-Atomic Fluorescence Spectrometry%流动注射氢化物发生原子荧光光谱法同时测定海水养殖基地环境介质As和Hg

    Institute of Scientific and Technical Information of China (English)

    黄月芳; 曹军; 丁智; 仇东辉; 郝玉凤

    2012-01-01

    应用氢化物发生原子荧光光谱技术,同时测定海水养殖基地环境介质底泥、海水和水产品中微量As和Hg.研究了载流、KBH4浓度对As和Hg测定的影响.在最佳实验操作条件下,As和Hg检出限分别为0.028 3 μg/L、0.017 4 μg/L.底泥中As和Hg的加标回收率分别为89.7%~ 112.6%和91.7% ~ 110.8%,相对标准偏差分别为2.7%~5.3%和2.2% ~4.3%;海水中As和Hg的加标回收率分别为90.2%~ 101.8%和90.0%~ 108.8%,相对标准偏差分别为3.1%~5.6%和2.1%~4.5%;水产品中As和Hg的加标回收率分别为89.6%~ 102.0%和89.2.0%~ 108.0%,相对标准偏差分别为2.6%~4.9%和1.7%~4.4%.%A systemic method for simultaneous determination of arsenic and mercury of sediment, seawater and fishery product in sea-water aquiculture base was developed by Hydride Generation-double channel Atomic Fluorescence Spectrometry ( HG-AFS). Effects of flowing acid and concentration of KBH4 solution on the determination of As and Hg were studied and optimized. The detection limits were found to be 0. 028 3 μg/L and 0. 017 4 μg/L for As and Hg, respectively. The proposed method was applied to the determination of As and Hg. The values of RSD's ( n = 10) were in the ranges of 2. 7% -5.3%(As) and2.2% -4.3%(Hg) in sediments, 3.1% -5.6%(As) and 2.1% -4.5%(Hg) in seawater, 2.6% -4.9%(As) and 1.7% -4.4% (Hg) in fishery product, respectively. Result s of recovery test were found in the ranges of 89. 7% -112. 6% (As) and 91.7% -110.8% (Hg) in sediments, 90.2% -101. 8% (As) and 90.0% -108.8% (Hg) in seawater, 89.6% -102.0% (As) and 89. 2.0% -108.0% (Hg) in fishery product, respectively.

  8. Anodematerials for Metal Hydride Batteries

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf

    1997-01-01

    This report describes the work on development of hydride forming alloys for use as electrode materials in metal hydride batteries. The work has primarily been concentrated on calcium based alloys derived from the compound CaNi5. This compound has a higher capacity compared with alloys used in today...... was developed. The parameters milling time, milling intensity, number of balls and form of the alloying metals were investigated. Based on this a final alloying technique for the subsequent preparation of electrode materials was established. The technique comprises milling for 4 hours twice possibly followed...... by annealing at 700°C for 12 hours. The alloys appeared to be nanocrystalline with an average crystallite size around 10 nm before annealing. Special steel containers was developed for the annealing of the metal powders in inert atmosphere. The use of various annealing temperatures was investigated...

  9. A novel speciation alternative for the determination of inorganic arsenic in marine samples

    DEFF Research Database (Denmark)

    Rasmussen, Rie Romme; Hedegaard, Rikke Susanne Vingborg; Herbst, M. Birgitte Koch;

    Arsenic (As) is bioaccumulated from seawater to concentrations in the mg/kg range in marine animals. More than 50 naturally-occurring arsenic containing species, both inorganic and organic forms, have been identified in marine animals. The organic forms are mainly considered to be non...... collected in the official EU food control today are reported as total arsenic. High Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS) is a useful but expensive tool for metal speciation analysis. Our novel, simple and inexpensive method for determination...... of inorganic arsenic in marine based food is based on microwave extraction, species separation by strong anion solid phase extraction (SPE) and hydride generation atomic absorption spectrometry (HG-AAS) detection. Separation organic arsenic compounds (e.g. MA, DMA and AB) and inorganic arsenic in the form...

  10. Nanostructured, complex hydride systems for hydrogen generation

    Directory of Open Access Journals (Sweden)

    Robert A. Varin

    2015-02-01

    Full Text Available Complex hydride systems for hydrogen (H2 generation for supplying fuel cells are being reviewed. In the first group, the hydride systems that are capable of generating H2 through a mechanical dehydrogenation phenomenon at the ambient temperature are discussed. There are few quite diverse systems in this group such as lithium alanate (LiAlH4 with the following additives: nanoiron (n-Fe, lithium amide (LiNH2 (a hydride/hydride system and manganese chloride MnCl2 (a hydride/halide system. Another hydride/hydride system consists of lithium amide (LiNH2 and magnesium hydride (MgH2, and finally, there is a LiBH4-FeCl2 (hydride/halide system. These hydride systems are capable of releasing from ~4 to 7 wt.% H2 at the ambient temperature during a reasonably short duration of ball milling. The second group encompasses systems that generate H2 at slightly elevated temperature (up to 100 °C. In this group lithium alanate (LiAlH4 ball milled with the nano-Fe and nano-TiN/TiC/ZrC additives is a prominent system that can relatively quickly generate up to 7 wt.% H2 at 100 °C. The other hydride is manganese borohydride (Mn(BH42 obtained by mechano-chemical activation synthesis (MCAS. In a ball milled (2LiBH4 + MnCl2 nanocomposite, Mn(BH42 co-existing with LiCl can desorb ~4.5 wt.% H2 at 100 °C within a reasonable duration of dehydrogenation. Practical application aspects of hydride systems for H2 generation/storage are also briefly discussed.

  11. Inhibited solid propellant composition containing beryllium hydride

    Science.gov (United States)

    Thompson, W. W. (Inventor)

    1978-01-01

    An object of this invention is to provide a composition of beryllium hydride and carboxy-terminated polybutadiene which is stable. Another object of this invention is to provide a method for inhibiting the reactivity of beryllium hydride toward carboxy-terminated polybutadiene. It was found that a small amount of lecithin inhibits the reaction of beryllium hydride with the acid groups in carboxy terminated polybutadiene.

  12. Crystal structure of gold hydride

    International Nuclear Information System (INIS)

    Highlights: • Volume expansion of metal hydrides is due to the increase in the s-band filling. • AuH structure is similar to that of Hg having one more s electron compared to Au. • Structure stability of both Hg and AuH is governed by the Hume-Rothery rule. - Abstract: A number of transition metal hydrides with close-packed metal sublattices of fcc or hcp structures with hydrogen in octahedral interstitial positions were obtained by the high-pressure-hydrogen technique described by Ponyatovskii et al. (1982). In this paper we consider volume increase of metals by hydrogenation and possible crystal structure of gold hydride in relation with the structure of mercury, the nearest neighbor of Au in the Periodic table. Suggested structure of AuH has a basic tetragonal body-centered cell that is very similar to the mercury structure Hg-t I 2. The reasons of stability for this structure are discussed within the model of Fermi sphere–Brillouin zone interactions

  13. Crystal structure of gold hydride

    Energy Technology Data Exchange (ETDEWEB)

    Degtyareva, Valentina F., E-mail: degtyar@issp.ac.ru

    2015-10-05

    Highlights: • Volume expansion of metal hydrides is due to the increase in the s-band filling. • AuH structure is similar to that of Hg having one more s electron compared to Au. • Structure stability of both Hg and AuH is governed by the Hume-Rothery rule. - Abstract: A number of transition metal hydrides with close-packed metal sublattices of fcc or hcp structures with hydrogen in octahedral interstitial positions were obtained by the high-pressure-hydrogen technique described by Ponyatovskii et al. (1982). In this paper we consider volume increase of metals by hydrogenation and possible crystal structure of gold hydride in relation with the structure of mercury, the nearest neighbor of Au in the Periodic table. Suggested structure of AuH has a basic tetragonal body-centered cell that is very similar to the mercury structure Hg-t I 2. The reasons of stability for this structure are discussed within the model of Fermi sphere–Brillouin zone interactions.

  14. Quantitative Determination of Arsenic in Bottled Drinking Water Using Atomic Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Maria Guţu Claudia

    2013-10-01

    Full Text Available Background: Many studies have been performed in the past few years, to determine arsenic speciation in drinking water, food chain and environment, arsenic being a well-recognized carcinogenic and toxic agent mainly in its inorganic species. The instrumental techniques used for arsenic determination, such as hydride generation atomic absorption spectrometry (HGAAS, graphite furnace atomic absorption spectrometry (GFAAS and inductively coupled plasma mass spectrometry (ICP-MS, can provide a great sensitivity only on the total amount. Objective: The aim of this study was to develop a simple and rapid method and to analyze the concentration of total inorganic arsenic in bottled drinking water. Methods: Total arsenic was determined in samples from six different types of commercially available bottled drinking water using atomic absorption spectrometry with electrothermal or hydride generation vaporisation. All drinking water samples were acidified with 0.1M nitric acid to match the acidity of the standards. Results: The method was linear within the studied range (1-5 μg/L, R = 0.9943. The quantification limits for arsenic determination were 0.48 μg/L (HGAAS and 0.03 μg/L (GFAAS. The evaluated arsenic content in drinking water was within the accepted limits provided by law. Conclusions: A simple and sensitive method for the quantification of arsenic in drinking water using atomic absorbtion spectroscopy was described, which can be further used in toxicological studies. As an additional advantage, the system is very fast, efficient and environmental friendly

  15. Research on Metal Hydride Compressor System

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Ti-Zr series Laves phase hydrogen storage alloys with good hydrogen storage properties, such as large hydrogen capacity, rapid hydriding and dehydriding rate, high compression ratio, gentle plateau, small hysteresis, easily being activated and long cyclic stability etc. for metal hydride compressor have been investigated. In addition, a hydride compressor with special characteristics, namely, advanced filling method, good heat transfer effect and reasonable structural design etc. has also been constructed. A hydride compressor cryogenic system has been assembled coupling the compressor with a J-T micro-throttling refrigeration device and its cooling capacity can reach 0.4 W at 25 K.

  16. Metal Hydrides for Rechargeable Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Valoeen, Lars Ole

    2000-03-01

    Rechargeable battery systems are paramount in the power supply of modern electronic and electromechanical equipment. For the time being, the most promising secondary battery systems for the future are the lithium-ion and the nickel metal hydride (NiMH) batteries. In this thesis, metal hydrides and their properties are described with the aim of characterizing and improving those. The thesis has a special focus on the AB{sub 5} type hydrogen storage alloys, where A is a rare earth metal like lanthanum, or more commonly misch metal, which is a mixture of rare earth metals, mainly lanthanum, cerium, neodymium and praseodymium. B is a transition metal, mainly nickel, commonly with additions of aluminium, cobalt, and manganese. The misch metal composition was found to be very important for the geometry of the unit cell in AB{sub 5} type alloys, and consequently the equilibrium pressure of hydrogen in these types of alloys. The A site substitution of lanthanum by misch metal did not decrease the surface catalytic properties of AB{sub 5} type alloys. B-site substitution of nickel with other transition elements, however, substantially reduced the catalytic activity of the alloy. If the internal pressure within the electrochemical test cell was increased using inert argon gas, a considerable increase in the high rate charge/discharge performance of LaNi{sub 5} was observed. An increased internal pressure would enable the utilisation of alloys with a high hydrogen equivalent pressure in batteries. Such alloys often have favourable kinetics and high hydrogen diffusion rates and thus have a potential for improving the high current discharge rates in metal hydride batteries. The kinetic properties of metal hydride electrodes were found to improve throughout their lifetime. The activation properties were found highly dependent on the charge/discharge current. Fewer charge/discharge cycles were needed to activate the electrodes if a small current was used instead of a higher

  17. Arsenic poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Furr, A.

    1977-01-01

    The route of arsenic exposure is usually by ingestion, thus the veterinarian is concerned with treating either an acute or a peracute condition. The arsenic compounds are considered to be highly toxic with a rapid onset of clinical signs. The toxicity and rapidity of onset are variable, depending upon the age and the species of animal. The chemical form and solubility of the toxicant also play a role in the course of the clinical syndrome. Inorganic arsenicals inhibit the sulfhydryl enzyme systems which are essential for normal cellular respiration and for metabolism of fats and carbohydrates. Therapeutic measures are intended to either remove or inactivate the unabsorbed material in the intestine, protect the alimentary tract, reverse the toxic syndrome and restore the homeostatic equilibrium of the animal. 5 references.

  18. Arsenic poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Low, D.G.

    1974-01-01

    The use of arsenic in ant poisons, herbicides, and insecticides affords the necessary contact with the poison by pets. The gastrointestinal tract appears to suffer the greatest though there may also be injury to the liver and kidneys. The treatments discussed were in relation to very early poisoning in which the owner had observed ingestion of the arsenic, and when the signs of the poisoning were evident. Early observation treatment included emptying the stomach before the arsenic passed in quantity into the intestine. If the signs of toxicity were already advanced, then the treatment consisted of the intramuscular administration of dimercaprol (BAL) at a dosage of 3 mg/lb of body weight three times a day until recovery. l reference.

  19. Kinetics of hydride front in Zircaloy-2 and H release from a fractional hydrided surface

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, M.; Gonzalez-Gonzalez, A.; Moya, J. S.; Remartinez, B.; Perez, S.; Sacedon, J. L. [Instituto de Ciencia de Materiales de Madrid (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain); Iberdrola, Tomas Redondo 3, 28033 Madrid (Spain); Instituto de Ciencia de Materiales de Madrid (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain)

    2009-07-15

    The authors study the hydriding process on commercial nuclear fuel claddings from their inner surface using an ultrahigh vacuum method. The method allows determining the incubation and failure times of the fuel claddings, as well as the dissipated energy and the partial pressure of the desorbed H{sub 2} from the outer surface of fuel claddings during the hydriding process. The correlation between the hydriding dissipated energy and the amount of zirconium hydride (formed at different stages of the hydriding process) leads to a near t{sup 1/2} potential law corresponding to the time scaling of the reaction for the majority of the tested samples. The calibrated relation between energy and hydride thickness allows one to calculate the enthalpy of the {delta}-ZrH{sub 1.5} phase. The measured H{sub 2} desorption from the external surface is in agreement with a proposed kinetic desorption model from the hydrides precipitated at the surface.

  20. Predicting formation enthalpies of metal hydrides

    DEFF Research Database (Denmark)

    Andreasen, A.

    2004-01-01

    In order for the hydrogen based society viz. a society in which hydrogen is the primary energy carrier to become realizable an efficient way of storing hydrogen is required. For this purpose metal hydrides are serious candidates. Metal hydrides are formedby chemical reaction between hydrogen and ...

  1. Changes in serum thioredoxin among individuals chronically exposed to arsenic in drinking water.

    Science.gov (United States)

    Li, Yuanyuan; Gao, Yanhui; Zhao, Lijun; Wei, Yudan; Feng, Hongqi; Wang, Cheng; Wei, Wei; Ding, Yunpeng; Sun, Dianjun

    2012-02-15

    It is well known that oxidative damage plays a key role in the development of chronic arsenicosis. There is a complex set of mechanisms of redox cycling in vivo to protect cells from the damage. In this study, we examined the differences in the levels of serum thioredoxin1 (TRX1) among individuals exposed to different levels of arsenic in drinking water and detected early biomarkers of arsenic poisoning before the appearance of skin lesions. A total of 157 subjects from endemic regions of China were selected and divided into arsenicosis group with skin lesions (total intake of arsenic: 8.68-45.71mg-year) and non-arsenicosis group without skin lesions, which further divided into low (0.00-1.06mg-year), medium (1.37-3.55mg-year), and high (4.26-48.13mg-year) arsenic exposure groups. Concentrations of serum TRX1 were analyzed by an ELISA method. Levels of water arsenic and urinary speciated arsenics, including inorganic arsenic (iAs), monomethylated arsenic (MMA), and dimethylated arsenic (DMA), were determined by hydride generation atomic absorption spectrometry. Our results showed that the levels of serum TRX1 in arsenicosis patients were significantly higher than that of the subjects who were chronically exposed to arsenic, but without skin lesions. A positive correlation was seen between the levels of serum TRX1 and the total water arsenic intake or the levels of urinary arsenic species. The results of this study indicate that arsenic exposure could significantly change the levels of human serum TRX1, which can be detected before arsenic-specific dermatological symptoms occur. This study provides further evidence on revealing the mechanism of arsenic toxicity.

  2. Submillimeter Spectroscopy of Hydride Molecules

    Science.gov (United States)

    Phillips, T. G.

    1998-05-01

    Simple hydride molecules are of great importance in astrophysics and astrochemistry. Physically they dominate the cooling of dense, warm phases of the ISM, such as the cores and disks of YSOs. Chemically they are often stable end points of chemical reactions, or may represent important intermediate stages of the reaction chains, which can be used to test the validity of the process. Through the efforts of astronomers, physicists, chemists, and laboratory spectroscopists we have an approximate knowledge of the abundance of some of the important species, but a great deal of new effort will be required to achieve the comprehensive and accurate data set needed to determine the energy balance and firmly establish the chemical pathways. Due to the low moment of inertia, the hydrides rotate rapidly and so have their fundamental spectral lines in the submillimeter. Depending on the cloud geometry and temperature profile they may be observed in emission or absorption. Species such as HCl, HF, OH, CH, CH(+) , NH_2, NH_3, H_2O, H_2S, H_3O(+) and even H_3(+) have been detected, but this is just a fraction of the available set. Also, most deduced abundances are not nearly sufficiently well known to draw definitive conclusions about the chemical processes. For example, the most important coolant for many regions, H_2O, has a possible range of deduced abundance of a factor of 1000. The very low submillimeter opacity at the South Pole site will be a significant factor in providing a new capabilty for interstellar hydride spectroscopy. The new species and lines made available in this way will be discussed.

  3. Arsenic in drinking water in Northern region of Serbia

    Directory of Open Access Journals (Sweden)

    Stanisavljev B.

    2013-04-01

    Full Text Available In this study we present the results of arsenic concentration in water samples from public water supply system of city Zrenjanin and three Northern municipalities Elemiš, Taraš and Melenci taken every month during 2002, 2007 and 2011. Total arsenic content was determined using AAS technique with hydride generation system. Determined levels of arsenic in all investigated samples were more than 10 times higher than the maximum permissible limit recommended by WHO (10 μg/L and even reached levels higher than 300 μg/L. During 2011 drinking water from 44 pump wells in Zrenjanin was also analyzed showing that more than 50% of pump wells contain more than 10 μg As/L. These findings can be explained by geological characteristics of Northern region of Serbia belonging to Pannonian Basin which has aquifers that contain high concentration of naturally occurring arsenic. Results suggest that arsenic levels in this Serbian region are even higher than in other countries in the Pannonian Basin. Having in mind profound deleterious effects of arsenic on human health, different social, economical and technological measures are required in order to reduce arsenic concentration to acceptable limits.

  4. The Total Arsenic Concentrations of Aquatic Products and the Assessment of Arsenic Intake from Aquatic Products in Guangzhou, China

    Directory of Open Access Journals (Sweden)

    Yu Guang-Hui

    2015-07-01

    Full Text Available The aim of this study was to assess the contribution of aquatic products consumed by the resident to the daily dietary arsenic intakes of the residents of Guangzhou of Guangdong province in China. All aquatic products were sampled from supermarkets and terminal markets. Accuracy was assured using standard reference material (GBW08551 and recovery experiments. Total arsenic concentrations of aquatic products were determined after acid digestion by hydride generation atomic fluorescent spectrometry. A wide range of arsenic concentration (0.0075-1.2017 mg/kg was found among the various aquatic products, the mean arsenic concentration in aquatic production was 0.2022 mg/kg. The arsenic concentrations of various aquatic products groups were as follows: Crustacean (0.3176±0.2324 mg/kg >Mollusk fish (0.1979±0.2013 mg/k >Saltwater fish (0.1558±0.1119 mg/kg >Freshwater fish (0.1374±0.0970 mg/kg. The range of daily dietary arsenic intake of various residents through the consumption of aquatic products was 5.96-11.85 µg/day. The freshwater fish had the largest contribution to the daily dietary arsenic intakes from aquatic products in all type aquatic products, accounted for around 50%.

  5. Phytoremediation assessment of Gomphrena globosa and Zinnia elegans grown in arsenic-contaminated hydroponic conditions as a safe and feasible alternative to be applied in arsenic-contaminated soils of the Bengal Delta.

    Science.gov (United States)

    Signes-Pastor, A J; Munera-Picazo, S; Burló, F; Cano-Lamadrid, M; Carbonell-Barrachina, A A

    2015-06-01

    Several agricultural fields show high contents of arsenic because of irrigation with arsenic-contaminated groundwater. Vegetables accumulate arsenic in their edible parts when grown in contaminated soils. Polluted vegetables are one of the main sources of arsenic in the food chain, especially for people living in rural arsenic endemic villages of India and Bangladesh. The aim of this study was to assess the feasibility of floriculture in the crop rotation system of arsenic endemic areas of the Bengal Delta. The effects of different arsenic concentrations (0, 0.5, 1.0, and 2.0 mg As L(-1)) and types of flowering plant (Gomphrena globosa and Zinnia elegans) on plant growth and arsenic accumulation were studied under hydroponic conditions. Total arsenic was quantified using atomic absorption spectrometer with hydride generation (HG-AAS). Arsenic was mainly accumulated in the roots (72 %), followed by leaves (12 %), stems (10 %), and flowers (<1 %). The flowering plants studied did not show as high phytoremediation capacities as other wild species, such as ferns. However, they behaved as arsenic tolerant plants and grew and bloomed well, without showing any phytotoxic signs. This study proves that floriculture could be included within the crop rotation system in arsenic-contaminated agricultural soils, in order to improve food safety and also food security by increasing farmer's revenue.

  6. Phytoremediation assessment of Gomphrena globosa and Zinnia elegans grown in arsenic-contaminated hydroponic conditions as a safe and feasible alternative to be applied in arsenic-contaminated soils of the Bengal Delta.

    Science.gov (United States)

    Signes-Pastor, A J; Munera-Picazo, S; Burló, F; Cano-Lamadrid, M; Carbonell-Barrachina, A A

    2015-06-01

    Several agricultural fields show high contents of arsenic because of irrigation with arsenic-contaminated groundwater. Vegetables accumulate arsenic in their edible parts when grown in contaminated soils. Polluted vegetables are one of the main sources of arsenic in the food chain, especially for people living in rural arsenic endemic villages of India and Bangladesh. The aim of this study was to assess the feasibility of floriculture in the crop rotation system of arsenic endemic areas of the Bengal Delta. The effects of different arsenic concentrations (0, 0.5, 1.0, and 2.0 mg As L(-1)) and types of flowering plant (Gomphrena globosa and Zinnia elegans) on plant growth and arsenic accumulation were studied under hydroponic conditions. Total arsenic was quantified using atomic absorption spectrometer with hydride generation (HG-AAS). Arsenic was mainly accumulated in the roots (72 %), followed by leaves (12 %), stems (10 %), and flowers (plants studied did not show as high phytoremediation capacities as other wild species, such as ferns. However, they behaved as arsenic tolerant plants and grew and bloomed well, without showing any phytotoxic signs. This study proves that floriculture could be included within the crop rotation system in arsenic-contaminated agricultural soils, in order to improve food safety and also food security by increasing farmer's revenue. PMID:26022848

  7. Metal hydrides as electrode/catalyst materials for oxygen evolution/reduction in electrochemical devices

    Science.gov (United States)

    Bugga, Ratnakumar V. (Inventor); Halpert, Gerald (Inventor); Fultz, Brent (Inventor); Witham, Charles K. (Inventor); Bowman, Robert C. (Inventor); Hightower, Adrian (Inventor)

    1997-01-01

    An at least ternary metal alloy of the formula, AB.sub.(5-Y)X(.sub.y), is claimed. In this formula, A is selected from the rare earth elements, B is selected from the elements of groups 8, 9, and 10 of the periodic table of the elements, and X includes at least one of the following: antimony, arsenic, and bismuth. Ternary or higher-order substitutions, to the base AB.sub.5 alloys, that form strong kinetic interactions with the predominant metals in the base metal hydride are used to form metal alloys with high structural integrity after multiple cycles of hydrogen sorption.

  8. Hydrogen-storing hydride complexes

    Science.gov (United States)

    Srinivasan, Sesha S.; Niemann, Michael U.; Goswami, D. Yogi; Stefanakos, Elias K.

    2012-04-10

    A ternary hydrogen storage system having a constant stoichiometric molar ratio of LiNH.sub.2:MgH.sub.2:LiBH.sub.4 of 2:1:1. It was found that the incorporation of MgH.sub.2 particles of approximately 10 nm to 20 nm exhibit a lower initial hydrogen release temperature of 150.degree. C. Furthermore, it is observed that the particle size of LiBNH quaternary hydride has a significant effect on the hydrogen sorption concentration with an optimum size of 28 nm. The as-synthesized hydrides exhibit two main hydrogen release temperatures, one around 160.degree. C. and the other around 300.degree. C., with the main hydrogen release temperature reduced from 310.degree. C. to 270.degree. C., while hydrogen is first reversibly released at temperatures as low as 150.degree. C. with a total hydrogen capacity of 6 wt. % to 8 wt. %. Detailed thermal, capacity, structural and microstructural properties have been demonstrated and correlated with the activation energies of these materials.

  9. Activated aluminum hydride hydrogen storage compositions and uses thereof

    Science.gov (United States)

    Sandrock, Gary; Reilly, James; Graetz, Jason; Wegrzyn, James E.

    2010-11-23

    In one aspect, the invention relates to activated aluminum hydride hydrogen storage compositions containing aluminum hydride in the presence of, or absence of, hydrogen desorption stimulants. The invention particularly relates to such compositions having one or more hydrogen desorption stimulants selected from metal hydrides and metal aluminum hydrides. In another aspect, the invention relates to methods for generating hydrogen from such hydrogen storage compositions.

  10. Metal interferences and their removal prior to the determination of As(T) and As(III) in acid mine waters by hydride generation atomic absorption spectrometry

    Science.gov (United States)

    McCleskey, R. Blaine; Nordstrom, D. Kirk; Ball, James W.

    2003-01-01

    Hydride generation atomic absorption spectrometry (HGAAS) is a sensitive and selective method for the determination of total arsenic (arsenic(III) plus arsenic(V)) and arsenic(III); however, it is subject to metal interferences for acid mine waters. Sodium borohydride is used to produce arsine gas, but high metal concentrations can suppress arsine production. This report investigates interferences of sixteen metal species including aluminum, antimony(III), antimony(V), cadmium, chromium(III), chromium(IV), cobalt, copper(II), iron(III), iron(II), lead, manganese, nickel, selenium(IV), selenium(VI), and zinc ranging in concentration from 0 to 1,000 milligrams per liter and offers a method for removing interfering metal cations with cation exchange resin. The degree of interference for each metal without cation-exchange on the determination of total arsenic and arsenic(III) was evaluated by spiking synthetic samples containing arsenic(III) and arsenic(V) with the potential interfering metal. Total arsenic recoveries ranged from 92 to 102 percent for all metals tested except antimony(III) and antimony(V) which suppressed arsine formation when the antimony(III)/total arsenic molar ratio exceeded 4 or the antimony(V)/total arsenic molar ratio exceeded 2. Arsenic(III) recoveries for samples spiked with aluminum, chromium(III), cobalt, iron(II), lead, manganese, nickel, selenium(VI), and zinc ranged from 84 to 107 percent over the entire concentration range tested. Low arsenic(III) recoveries occurred when the molar ratios of metals to arsenic(III) were copper greater than 120, iron(III) greater than 70, chromium(VI) greater than 2, cadmium greater than 800, antimony(III) greater than 3, antimony(V) greater than 12, or selenium(IV) greater than 1. Low recoveries result when interfering metals compete for available sodium borohydride, causing incomplete arsine production, or when the interfering metal oxidizes arsenic(III). Separation of interfering metal cations using

  11. Experimental reproducibility analysis in DU hydriding

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Daeseo; Park, Jongcheol; Chung, Hongsuk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    A storage and delivery system (SDS) is used for storing hydrogen isotopes as a metal hydride form. The rapid hydriding of tritium is very important not only for safety reasons but also for the economic design and operation of the SDS. For the storage, supply, and recovery of hydrogen isotopes, depleted uranium (DU) has been extensively proposed. To develop nuclear fusion technology, it will be necessary to store and supply hydrogen isotopes needed for Tokamak operation. The experimental reproducibility of bed temperature on DU hydriding was also analyzed. The experimental reproducibility of apparatus was acceptable for all the experiments. The experimental reproducibility of tank pressure on DU hydriding was analyzed. As the hydriding performs, the tank pressure showed decreasing trend. The experimental reproducibility of bed temperature on DU hydriding was also analyzed. As the hydriding performs, the bed temperatures increased up to maximum temperature with exothermic reaction and then they showed decreasing trend. The experimental reproducibility of apparatus was acceptable for all the experiments.

  12. Inorganic arsenic - SPE HG-AAS method for RICE tested in-house and collaboratively

    DEFF Research Database (Denmark)

    Rasmussen, Rie Romme; Qian, Yiting; Sloth, Jens Jørgen

    Arsenic (As) is a trace element present in the environment and consequently in various food items, e.g. rice, which may contain relatively high concentration of arsenic compared to other foodstuffs of plant origin. Rice contains most often three forms of arsenic; inorganic arsenic (i...... and is one of the major contributors to the iAs exposure in many countries. The work presented here describes the development, validation and application of a simple and inexpensive method for inorganic arsenic (iAs) determination in rice samples. The separation of iAs from organoarsenic compounds (MA...... and DMA) was done by off-line solidphase extraction (SPE) followed by hydride generation atomic absorption spectrometry (HG-AAS) detection. Water bath heating (90 °C, 60 min) of samples with dilute nitric acid and hydrogen peroxide solubilised and oxidized all iAs to arsenate (AsV). Loading of buffered...

  13. Hydrogen adsorption on palladium and palladium hydride at 1 bar

    DEFF Research Database (Denmark)

    Johansson, Martin; Skulason, Egill; Nielsen, Gunver;

    2010-01-01

    strongly to Pd hydride than to Pd. The activation barrier for desorption at a H coverage of one mono layer is slightly lower on Pd hydride, whereas the activation energy for adsorption is similar on Pd and Pd hydride. It is concluded that the higher sticking probability on Pd hydride is most likely caused...... by a slightly lower equilibrium coverage of H, which is a consequence of the lower heat of adsorption for H on Pd hydride....

  14. Speciation of arsenic in environmental samples of the Nha Trang Harbor, Vietnam, using HPLC coupled HG-AAS.

    Science.gov (United States)

    Le, Lan Anh; Trinh, Anh Duc; Nguyen, Dinh Thuat; Bui, Minh Ly

    2011-04-01

    A coupled high performance liquid chromatography-hydride generation-atomic absorption spectroscopy system was used to determine the speciation of arsenic in samples from the Nha Trang Harbor, Vietnam. Concentrations of arsenic in seawater, pore water, suspended solid, and sediment were 4.12-9.81 μg/L, 13.10-24.32 μg/L, 1.87-6.42 μg/g, and 3.37-9.06 μg/g, respectively. Extraction using H(3)PO(4) + NH(2)OH·HCl and ultrasonic digestion was optimized to yield a 76-85% of total arsenic. Arsenic (III) was the most abundant species in suspended solids and sediments whereas arsenic (V) represented for 30-50% of arsenic (III) concentration. Monomethylarsonic acid and dimethylarsinic acid species were undetectable. PMID:21365299

  15. Hydride heat pump with heat regenerator

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative hydride heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system. A series of at least four canisters containing a lower temperature performing hydride and a series of at least four canisters containing a higher temperature performing hydride is provided. Each canister contains a heat conductive passageway through which a heat transfer fluid is circulated so that sensible heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  16. Biomonitoring for chromium and arsenic in timber treatment plant workers exposed to CCA wood Preservatives.

    Science.gov (United States)

    Cocker, J; Morton, J; Warren, N; Wheeler, J P; Garrod, A N I

    2006-07-01

    This study reports a survey of occupational exposure to copper chrome arsenic (CCA) based wood preservatives during vacuum pressure timber impregnation. The survey involved biological monitoring based on analysis of chromium and arsenic in urine samples collected from UK workers. The aim of the study was to determine the extent of occupational exposure to arsenic and chromium in the UK timber treatment industry. The objectives were to collect and analyse urine samples from as many workers as possible, where CCA wood preservatives might be used, at 6 monthly intervals for 2 years. In addition, to investigate day-to-day variations in urinary excretion of chrome and arsenic by collecting and analysing three samples a week for 3 weeks in subsets of workers and controls (people not occupationally exposed). All urine samples were analysed for chromium and inorganic arsenic. To investigate any residual interference every sample was accompanied by a short questionnaire about recent consumption of seafood and smoking. The analytical methods for arsenic used a hydride generation technique to reduce interference from dietary sources of arsenic and also a technique that would measure total arsenic concentration in urine. The main findings show that workers exposed to CCA wood preservatives have concentrations of inorganic arsenic and chromium in urine that are significantly higher than those from non-occupationally exposed people but below biological monitoring guidance values that would indicate inhalation exposure at UK occupational exposure limits for chromium and arsenic. The effects of consumption of seafood on urinary arsenic were not significant using the hydride generation method for inorganic arsenic but were significant if 'total' arsenic was measured. The 'total' arsenic method could not distinguish CCA workers from controls and is clearly unsuitable for assessment of occupational exposure to arsenic. There was a significant increase in the urinary concentration of

  17. Inorganic arsenic exposure and type 2 diabetes mellitus in Mexico.

    Science.gov (United States)

    Coronado-González, José Antonio; Del Razo, Luz María; García-Vargas, Gonzalo; Sanmiguel-Salazar, Francisca; Escobedo-de la Peña, Jorge

    2007-07-01

    Inorganic arsenic exposure in drinking water has been recently related to diabetes mellitus. To evaluate this relationship the authors conducted in 2003, a case-control study in an arseniasis-endemic region from Coahuila, a northern state of Mexico with a high incidence of diabetes. The present analysis includes 200 cases and 200 controls. Cases were obtained from a previous cross-sectional study conducted in that region. Diagnosis of diabetes was established following the American Diabetes Association criteria, with two fasting glucose values > or = 126 mg/100 ml (> or = 7.0 mmol/l) or a history of diabetes treated with insulin or oral hypoglycemic agents. The next subject studied, subsequent to the identification of a case in the cross-sectional study was taken as control. Inorganic arsenic exposure was measured through total arsenic concentrations in urine, measured by hydride-generation atomic absorption spectrophotometry. Subjects with intermediate total arsenic concentration in urine (63.5-104 microg/g creatinine) had two-fold higher risk of having diabetes (odds ratio=2.16; 95% confidence interval: 1.23, 3.79), but the risk was almost three times greater in subjects with higher concentrations of total arsenic in urine (odds ratio=2.84; 95% confidence interval: 1.64, 4.92). This data provides additional evidence that inorganic arsenic exposure may be diabetogenic.

  18. Urinary total arsenic and 8-hydroxydeoxyguanosine are associated with renal cell carcinoma in an area without obvious arsenic exposure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chao-Yuan [Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Department of Urology, National Taiwan University Hospital, College of Medicine National Taiwan University, Taipei, Taiwan (China); Su, Chien-Tien [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Chung, Chi-Jung [Department of Health Risk Management, College of Public Health, China Medical University, Taichung, Taiwan (China); Department of Medical Research, China Medical University Hospital, Taichung, Taiwan (China); Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, College of Medicine National Taiwan University, Taipei, Taiwan (China); Chu, Jan-Show [Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Department of Pathology, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Yang, Hsiu-Yuan [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Wu, Chia-Chang [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Urology, Taipei Medical Universtiy-Shuang Ho Hospital, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China)

    2012-08-01

    8-Hydroxydeoxyguanosine (8-OHdG) is one of the most reliable and abundant markers of DNA damage. The study was designed to explore the relationship between urinary 8-OHdG and renal cell carcinoma (RCC) and to investigate whether individuals with a high level of 8-OHdG would have a modified odds ratio (OR) of arsenic-related RCC. This case–control study was conducted with 132 RCC patients and 245 age- and sex-matched controls from a hospital-based pool between November 2006 and May 2009. Pathological verification of RCC was completed by image-guided biopsy or surgical resection of renal tumors. Urinary 8-OHdG levels were determined using liquid chromatography with tandem mass spectrometry (LC–MS/MS). Concentrations of urinary arsenic species, including inorganic arsenic, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), were determined by a high performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Level of urinary 8-OHdG was significantly associated with the OR of RCC in a dose–response relationship after multivariate adjustment. Urinary 8-OHdG was significantly related to urinary total arsenic. The greatest OR (3.50) was seen in the individuals with high urinary 8-OHdG and high urinary total arsenic. A trend test indicated that the OR of RCC was increased with one of these factors and was further increased with both (p = 0.002). In conclusion, higher urinary 8-OHdG was a strong predictor of the RCC. High levels of 8-OHdG combined with urinary total arsenic might be indicative of arsenic-induced RCC. -- Highlights: ► Urinary 8-OHdG was significantly related to urinary total arsenic. ► Higher urinary 8-OHdG was a strong predictor of RCC risk. ► Urinary 8-OHdG may modify arsenic related RCC risk.

  19. Urinary total arsenic and 8-hydroxydeoxyguanosine are associated with renal cell carcinoma in an area without obvious arsenic exposure

    International Nuclear Information System (INIS)

    8-Hydroxydeoxyguanosine (8-OHdG) is one of the most reliable and abundant markers of DNA damage. The study was designed to explore the relationship between urinary 8-OHdG and renal cell carcinoma (RCC) and to investigate whether individuals with a high level of 8-OHdG would have a modified odds ratio (OR) of arsenic-related RCC. This case–control study was conducted with 132 RCC patients and 245 age- and sex-matched controls from a hospital-based pool between November 2006 and May 2009. Pathological verification of RCC was completed by image-guided biopsy or surgical resection of renal tumors. Urinary 8-OHdG levels were determined using liquid chromatography with tandem mass spectrometry (LC–MS/MS). Concentrations of urinary arsenic species, including inorganic arsenic, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), were determined by a high performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Level of urinary 8-OHdG was significantly associated with the OR of RCC in a dose–response relationship after multivariate adjustment. Urinary 8-OHdG was significantly related to urinary total arsenic. The greatest OR (3.50) was seen in the individuals with high urinary 8-OHdG and high urinary total arsenic. A trend test indicated that the OR of RCC was increased with one of these factors and was further increased with both (p = 0.002). In conclusion, higher urinary 8-OHdG was a strong predictor of the RCC. High levels of 8-OHdG combined with urinary total arsenic might be indicative of arsenic-induced RCC. -- Highlights: ► Urinary 8-OHdG was significantly related to urinary total arsenic. ► Higher urinary 8-OHdG was a strong predictor of RCC risk. ► Urinary 8-OHdG may modify arsenic related RCC risk.

  20. Geoneutrino and Hydridic Earth model. Version 2

    OpenAIRE

    Bezrukov, Leonid

    2013-01-01

    Uranium, Thorium and Potassium-40 abundances in the Earth were calculated in the frame of Hydridic Earth model. Terrestrial heat producton from U, Th and K40 decays was calculated also. We must admit the existance of Earth expansion process to understand the obtained large value of terrestrial heat producton. The geoneutrino detector with volume more than 5 kT (LENA type) must be constructed to definitely separate between Bulk Silicat Earth model and Hydridic Earth model. In second version of...

  1. Atomistic Potentials for Palladium-Silver Hydrides

    OpenAIRE

    Hale, L. M.; Wong, B. M.; Zimmerman, J. A.; Zhou, X.

    2013-01-01

    New EAM potentials for the ternary palladium-silver-hydrogen system are developed by extending a previously developed palladium-hydrogen potential. The ternary potentials accurately capture the heat of mixing and structural properties associated with solid solution alloys of palladium-silver. Stable hydrides are produced with properties that smoothly transition across the compositions. Additions of silver to palladium are predicted to alter the properties of the hydrides by decreasing the mis...

  2. Earth Abides Arsenic Biotransformations

    Science.gov (United States)

    Zhu, Yong-Guan; Yoshinaga, Masafumi; Zhao, Fang-Jie; Rosen, Barry P.

    2014-05-01

    Arsenic is the most prevalent environmental toxic element and causes health problems throughout the world. The toxicity, mobility, and fate of arsenic in the environment are largely determined by its speciation, and arsenic speciation changes are driven, at least to some extent, by biological processes. In this article, biotransformation of arsenic is reviewed from the perspective of the formation of Earth and the evolution of life, and the connection between arsenic geochemistry and biology is described. The article provides a comprehensive overview of molecular mechanisms of arsenic redox and methylation cycles as well as other arsenic biotransformations. It also discusses the implications of arsenic biotransformation in environmental remediation and food safety, with particular emphasis on groundwater arsenic contamination and arsenic accumulation in rice.

  3. Inorganic arsenic in starchy roots, tubers, and plantain and assessment of cancer risk of sub-Saharan African populations

    Science.gov (United States)

    Starchy roots, tubers, and plantain (RTP) are the staple food in sub-Saharan Africa, and also important energy sources in Asia, Europe, and America. In this work, inorganic arsenic (iAs) in these crops was quantified by hydride generation-atomic fluorescence spectrometry (HG-AFS) after solid phase e...

  4. Total arsenic in selected food samples from Argentina: Estimation of their contribution to inorganic arsenic dietary intake.

    Science.gov (United States)

    Sigrist, Mirna; Hilbe, Nandi; Brusa, Lucila; Campagnoli, Darío; Beldoménico, Horacio

    2016-11-01

    An optimized flow injection hydride generation atomic absorption spectroscopy (FI-HGAAS) method was used to determine total arsenic in selected food samples (beef, chicken, fish, milk, cheese, egg, rice, rice-based products, wheat flour, corn flour, oats, breakfast cereals, legumes and potatoes) and to estimate their contributions to inorganic arsenic dietary intake. The limit of detection (LOD) and limit of quantification (LOQ) values obtained were 6μgkg(-)(1) and 18μgkg(-)(1), respectively. The mean recovery range obtained for all food at a fortification level of 200μgkg(-)(1) was 85-110%. Accuracy was evaluated using dogfish liver certified reference material (DOLT-3 NRC) for trace metals. The highest total arsenic concentrations (in μgkg(-)(1)) were found in fish (152-439), rice (87-316) and rice-based products (52-201). The contribution to inorganic arsenic (i-As) intake was calculated from the mean i-As content of each food (calculated by applying conversion factors to total arsenic data) and the mean consumption per day. The primary contributors to inorganic arsenic intake were wheat flour, including its proportion in wheat flour-based products (breads, pasta and cookies), followed by rice; both foods account for close to 53% and 17% of the intake, respectively. The i-As dietary intake, estimated as 10.7μgday(-)(1), was significantly lower than that from drinking water in vast regions of Argentina. PMID:27211625

  5. Probing the cerium/cerium hydride interface using nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Brierley, Martin, E-mail: martin.brierley@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom); University of Manchester, Manchester M13 9PL (United Kingdom); Knowles, John, E-mail: john.knowles@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom)

    2015-10-05

    Highlights: • A disparity exists between the minimum energy and actual shape of a cerium hydride. • Cerium hydride is found to be harder than cerium metal by a ratio of 1.7:1. • A zone of material under compressive stress was identified surrounding the hydride. • No distribution of hardness was apparent within the hydride. - Abstract: A cerium hydride site was sectioned and the mechanical properties of the exposed phases (cerium metal, cerium hydride, oxidised cerium hydride) were measured using nanoindentation. An interfacial region under compressive stress was observed in the cerium metal surrounding a surface hydride that formed as a consequence of strain energy generated by the volume expansion associated with precipitation of the hydride phase.

  6. Probing the cerium/cerium hydride interface using nanoindentation

    International Nuclear Information System (INIS)

    Highlights: • A disparity exists between the minimum energy and actual shape of a cerium hydride. • Cerium hydride is found to be harder than cerium metal by a ratio of 1.7:1. • A zone of material under compressive stress was identified surrounding the hydride. • No distribution of hardness was apparent within the hydride. - Abstract: A cerium hydride site was sectioned and the mechanical properties of the exposed phases (cerium metal, cerium hydride, oxidised cerium hydride) were measured using nanoindentation. An interfacial region under compressive stress was observed in the cerium metal surrounding a surface hydride that formed as a consequence of strain energy generated by the volume expansion associated with precipitation of the hydride phase

  7. The relationship between obesity, insulin and arsenic methylation capability in Taiwan adolescents

    International Nuclear Information System (INIS)

    Purpose: This study evaluated the arsenic methylation profile of adolescents and explored the influence of body mass index (BMI) on the arsenic methylation profile of adolescents in an area of Taiwan with no-obvious arsenic exposure. Methods: This study evaluated 202 normal weight students and 101 obese students from eight elementary schools, recruited from September 2009 to December 2009. Concentrations of urinary arsenic species, including inorganic arsenic, monomethylarsonic acid (MMA5+) and dimethylarsinic acid (DMA5+) were determined by a high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Results: Urinary total arsenic was significantly decreased with increasing BMI, indicating that obese children may retain higher levels of arsenic in the body, as compared to normal weight children. Participants with obesity accompanied by high insulin levels had higher inorganic arsenic, significantly higher MMA percentage and significantly lower DMA percentage than those with obesity and low insulin levels. It seems children with obesity and high insulin levels had lower arsenic methylation capacity than those with obesity and low insulin. Conclusions: This is the first study to demonstrate that total urinary arsenic is negatively associated with the BMI in adolescents in Taiwan, adjusted for age and sex. Obese adolescents with high insulin levels had significantly higher MMA% and significantly lower DMA% than obese adolescents with low insulin. - Highlights: ► This is the first to find that urinary total arsenic is related inversely to the BMI. ► Arsenic methylation capability may be associated with obesity and insulin. ► Obese adolescents with high insulin had low arsenic methylation capacity.

  8. The relationship between obesity, insulin and arsenic methylation capability in Taiwan adolescents

    Energy Technology Data Exchange (ETDEWEB)

    Su, Chien-Tien [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Lin, Hsiu-Chen [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Choy, Cheuk-Sing [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Emergency Department, Taipei Hospital, Department of Health, Taiwan (China); Huang, Yung-Kai [School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan (China); Huang, Shiau-Rung [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2012-01-01

    Purpose: This study evaluated the arsenic methylation profile of adolescents and explored the influence of body mass index (BMI) on the arsenic methylation profile of adolescents in an area of Taiwan with no-obvious arsenic exposure. Methods: This study evaluated 202 normal weight students and 101 obese students from eight elementary schools, recruited from September 2009 to December 2009. Concentrations of urinary arsenic species, including inorganic arsenic, monomethylarsonic acid (MMA{sup 5+}) and dimethylarsinic acid (DMA{sup 5+}) were determined by a high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Results: Urinary total arsenic was significantly decreased with increasing BMI, indicating that obese children may retain higher levels of arsenic in the body, as compared to normal weight children. Participants with obesity accompanied by high insulin levels had higher inorganic arsenic, significantly higher MMA percentage and significantly lower DMA percentage than those with obesity and low insulin levels. It seems children with obesity and high insulin levels had lower arsenic methylation capacity than those with obesity and low insulin. Conclusions: This is the first study to demonstrate that total urinary arsenic is negatively associated with the BMI in adolescents in Taiwan, adjusted for age and sex. Obese adolescents with high insulin levels had significantly higher MMA% and significantly lower DMA% than obese adolescents with low insulin. - Highlights: Black-Right-Pointing-Pointer This is the first to find that urinary total arsenic is related inversely to the BMI. Black-Right-Pointing-Pointer Arsenic methylation capability may be associated with obesity and insulin. Black-Right-Pointing-Pointer Obese adolescents with high insulin had low arsenic methylation capacity.

  9. Atomic absorption determination, in metal sulphide concentrates, of the elements that form gaseous hydrides

    International Nuclear Information System (INIS)

    An account is given of the investigational work on the determination of trace amounts of arsenic, antimony, bismuth, germanium, selenium, and tellurium by the technique using hydride generation and atomic-absorption spectrophotometry. The gaseous hydride is generated by reduction with sodium borohydride, and is subsequently swept by a flow of nitrogen into an air-entrained hydrogen-nitrogen flame. The generation equipment used is simple and inexpensive, and can be readily assembled in most laboratories. The optimum parameters were determined for each element. The effects of 31 probable interfering elements were investigated, and it was found that, although the majority did not interfere, severe interference was encountered when copper, nickel, and the noble metals were present. Methods for the elimination of copper and nickel were developed to allow the determination of arsenic, antimony, bismuth, selenium, and tellurium at the lower parts-per-million level in metal sulphide concentrates with an acceptable accuracy and precision. The determination of microgram amounts of germanium was found to be unsatisfactory

  10. Flame-in-gas-shield and miniature diffusion flame hydride atomizers for atomic fluorescence spectrometry: optimization and comparison

    International Nuclear Information System (INIS)

    A detailed optimization of relevant experimental parameters of two hydride atomizers for atomic fluorescence spectrometry: flame-in-gas-shield atomizer with a two-channel shielding unit and a standard atomizer for atomic fluorescence spectrometry, miniature diffusion flame, was performed. Arsine, generated by the reaction with NaBH4 in a flow injection arrangement, was chosen as the model hydride. Analytical characteristics of both the atomizers (sensitivity, noise, limits of detection) were compared. Under optimum conditions sensitivity obtained with flame-in-gas-shield atomizer was approximately twice higher than with miniature diffusion flame. The additional advantage of flame-in-gas-shield atomizer is significantly lower flame emission resulting in a better signal to noise ratio. The resulting arsenic limits of detection for miniature diffusion flame and flame-in-gas-shield atomizer were 3.8 ng l−1 and 1.0 ng l−1, respectively. - Highlights: • We optimized and compared two hydride atomizers for atomic fluorescence spectrometry. • Miniature diffusion flame and flame-in-gas-shield atomizer were optimized. • The limit of detection for arsenic was 1.0 ng l−1

  11. Flame-in-gas-shield and miniature diffusion flame hydride atomizers for atomic fluorescence spectrometry: optimization and comparison

    Energy Technology Data Exchange (ETDEWEB)

    Marschner, Karel, E-mail: karel.marschner@biomed.cas.cz [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Charles University in Prague, Faculty of Science, Department of Analytical Chemistry, Albertov 8, 128 43 Prague (Czech Republic); Musil, Stanislav; Dědina, Jiří [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic)

    2015-07-01

    A detailed optimization of relevant experimental parameters of two hydride atomizers for atomic fluorescence spectrometry: flame-in-gas-shield atomizer with a two-channel shielding unit and a standard atomizer for atomic fluorescence spectrometry, miniature diffusion flame, was performed. Arsine, generated by the reaction with NaBH{sub 4} in a flow injection arrangement, was chosen as the model hydride. Analytical characteristics of both the atomizers (sensitivity, noise, limits of detection) were compared. Under optimum conditions sensitivity obtained with flame-in-gas-shield atomizer was approximately twice higher than with miniature diffusion flame. The additional advantage of flame-in-gas-shield atomizer is significantly lower flame emission resulting in a better signal to noise ratio. The resulting arsenic limits of detection for miniature diffusion flame and flame-in-gas-shield atomizer were 3.8 ng l{sup −1} and 1.0 ng l{sup −1}, respectively. - Highlights: • We optimized and compared two hydride atomizers for atomic fluorescence spectrometry. • Miniature diffusion flame and flame-in-gas-shield atomizer were optimized. • The limit of detection for arsenic was 1.0 ng l{sup −1}.

  12. gamma-Zr-Hydride Precipitate in Irradiated Massive delta- Zr-Hydride

    DEFF Research Database (Denmark)

    Warren, M. R.; Bhattacharya, D. K.

    1975-01-01

    During examination of A Zircaloy-2-clad fuel pin, which had been part of a test fuel assembly in a boiling water reactor, several regions of severe internal hydriding were noticed in the upper-plenum end of the pin. Examination of similar fuel pins has shown that hydride of this type is caused...

  13. Elevated lactate dehydrogenase activity and increased cardiovascular mortality in the arsenic-endemic areas of southwestern Taiwan

    International Nuclear Information System (INIS)

    Arsenic ingestion has been linked to increasing global prevalence of and mortality from cardiovascular disease (CVD); arsenic can be removed from drinking water to reduce related health effects. Lactate dehydrogenase (LDH) is used for the evaluation of acute arsenic toxicity in vivo and in vitro, but it is not validated for the evaluation of long-term, chronic arsenic exposure. The present study examined the long-term effect of chronic arsenic exposure on CVD and serum LDH levels, after consideration of arsenic metabolism capacity. A total of 380 subjects from an arseniasis-endemic area and 303 from a non-endemic area of southwestern Taiwan were recruited in 2002. Various urinary arsenic species were analyzed using high-performance liquid chromatography (HPLC) and hydride generation systems. Fasting serum was used for quantitative determination of the total LDH activity. A significant dose–response relationship was observed between arsenic exposure and LDH elevation, independent of urinary arsenic profiles (P < 0.001). Furthermore, abnormal LDH elevation was associated with CVD mortality after adjustment for Framingham risk scores for 10-year CVD and arsenic exposure (hazard ratio, 3.98; 95% confidence interval, 1.07–14.81). LDH was elevated in subjects with arsenic exposure in a dose-dependent manner. LDH is a marker of arsenic toxicity associated with CVD mortality. Results of this study have important implications for use in ascertaining long-term arsenic exposure risk of CVD. -- Highlights: ► We showed that arsenic exposure was correlated with LDH elevation. ► LDH elevation was related to arsenic methylation capacity. ► Abnormal LDH elevation can be a marker of susceptibility to CVD mortality.

  14. Elevated lactate dehydrogenase activity and increased cardiovascular mortality in the arsenic-endemic areas of southwestern Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Ya-Tang [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Taiwan (China); Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taiwan (China); Genomics Research Center, Academia Sinica, Taiwan (China); Chen, Chien-Jen [Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taiwan (China); Genomics Research Center, Academia Sinica, Taiwan (China); Li, Wan-Fen [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Taiwan (China); Hsu, Ling-I [Genomics Research Center, Academia Sinica, Taiwan (China); Tsai, Li-Yu; Huang, Yeou-Lih [Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Taiwan (China); Sun, Chien-Wen [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Taiwan (China); Chen, Wei J., E-mail: wjchen@ntu.edu.tw [Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taiwan (China); Genetic Epidemiology Core Laboratory, National Taiwan University Center for Genomic Medicine, Taiwan (China); Wang, Shu-Li, E-mail: slwang@nhri.org.tw [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Taiwan (China); Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan (China)

    2012-08-01

    Arsenic ingestion has been linked to increasing global prevalence of and mortality from cardiovascular disease (CVD); arsenic can be removed from drinking water to reduce related health effects. Lactate dehydrogenase (LDH) is used for the evaluation of acute arsenic toxicity in vivo and in vitro, but it is not validated for the evaluation of long-term, chronic arsenic exposure. The present study examined the long-term effect of chronic arsenic exposure on CVD and serum LDH levels, after consideration of arsenic metabolism capacity. A total of 380 subjects from an arseniasis-endemic area and 303 from a non-endemic area of southwestern Taiwan were recruited in 2002. Various urinary arsenic species were analyzed using high-performance liquid chromatography (HPLC) and hydride generation systems. Fasting serum was used for quantitative determination of the total LDH activity. A significant dose–response relationship was observed between arsenic exposure and LDH elevation, independent of urinary arsenic profiles (P < 0.001). Furthermore, abnormal LDH elevation was associated with CVD mortality after adjustment for Framingham risk scores for 10-year CVD and arsenic exposure (hazard ratio, 3.98; 95% confidence interval, 1.07–14.81). LDH was elevated in subjects with arsenic exposure in a dose-dependent manner. LDH is a marker of arsenic toxicity associated with CVD mortality. Results of this study have important implications for use in ascertaining long-term arsenic exposure risk of CVD. -- Highlights: ► We showed that arsenic exposure was correlated with LDH elevation. ► LDH elevation was related to arsenic methylation capacity. ► Abnormal LDH elevation can be a marker of susceptibility to CVD mortality.

  15. The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components Delayed Hydride Cracking

    CERN Document Server

    Puls, Manfred P

    2012-01-01

    By drawing together the current theoretical and experimental understanding of the phenomena of delayed hydride cracking (DHC) in zirconium alloys, The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components: Delayed Hydride Cracking provides a detailed explanation focusing on the properties of hydrogen and hydrides in these alloys. Whilst the focus lies on zirconium alloys, the combination of both the empirical and mechanistic approaches creates a solid understanding that can also be applied to other hydride forming metals.   This up-to-date reference focuses on documented research surrounding DHC, including current methodologies for design and assessment of the results of periodic in-service inspections of pressure tubes in nuclear reactors. Emphasis is placed on showing that our understanding of DHC is supported by progress across a broad range of fields. These include hysteresis associated with first-order phase transformations; phase relationships in coherent crystalline metallic...

  16. Massive acute arsenic poisonings.

    Science.gov (United States)

    Lech, Teresa; Trela, Franciszek

    2005-07-16

    Arsenic poisonings are still important in the field of toxicology, though they are not as frequent as about 20-30 years ago. In this paper, the arsenic concentrations in ante- and post-mortem materials, and also forensic and anatomo-pathological aspects in three cases of massive acute poisoning with arsenic(III) oxide (two of them with unexplained criminalistic background, in which arsenic was taken for amphetamine and one suicide), are presented. Ante-mortem blood and urine arsenic concentrations ranged from 2.3 to 6.7 microg/ml, respectively. Post-mortem tissue total arsenic concentrations were also detected in large concentrations. In case 3, the contents of the duodenum contained as much as 30.1% arsenic(III) oxide. The high concentrations of arsenic detected in blood and tissues in all presented cases are particularly noteworthy in that they are very rarely detected at these concentrations in fatal arsenic poisonings. PMID:15939162

  17. Cuantificación de arsénico por inyeccion en flujo-generación de hidruros-espectrometría de abosorcion atómica (IF-GH-EAA previa derivatzación con l-cisteína: Validación y comparación intermetodológica utilizando dos técnicas de referencia Arsenic quantitation by flow injection-hydride generation-atomicabsorption spectrometry (FI-HG-AAS after l-cysteine derivatization: Validation and inter-methodological comparison using two reference techniques

    Directory of Open Access Journals (Sweden)

    Julio A Navoni

    2010-12-01

    utilizando IF-GH-EAA, resultaron comparables al nivel basal previo al consumo. Los resultados obtenidos indican que la metodología propuesta es una alternativa válida para evaluar la exposición a As inorgánico sin necesidad de utilizar prolongados pre-tratamientos, resultando más económica y rápida y evitando la sobreestimación por medición de otras especies del arsénico de bajo impacto toxicológico.The presence of arsenic (As in drinking water is a public health concern in many regions of the world, including Argentina. Quantification of arsenic in drinking water and urine are used to assess exposure to this pollutant. This study aimed to validate a methodology for the quantification of As species [AsV + AsIII + acid monometilarsónico (MMA + dimetilarsínico acid (DMA] by flow injection-hydride generation-atomic absorption spectrometry (FI-HG-AAS, after derivatization with L-cysteine. The results were compared with those obtained using two methods of reference, hydride generation-atomic absorption spectrometry (HG-AAS for water and urine samples, and high performance liquid chromatography-hydride generation-atomic absorption spectrometry (HPLC-HG-AAS for urine samples. In addition, the selectivity of quantification by FI-HG-AAS in the presence of other chemical species of As, from fishery products intake, was evaluated through a biological assay. The As level found in water and urine samples, using the techniques of reference, showed a range from 6 to 176 μg/L and from 143 to 3312 μg/g creatinine, respectively. Pearson coefficients resulting from the comparison of data obtained by FI-HG-AAS with those achieved by the reference methods were r = 0.9976 and r = 0.9422 for water and urine, respectively. The results of the biological test showed a higher level of As, due to consumption of food fishery product, when urine samples were previously mineralized (HG-AAS, with consequent overestimation of the inorganic arsenic consumption. When these samples were analyzed

  18. Arsenic Metabolites and Methylation Capacity Among Individuals Living in a Rural Area with Endemic Arseniasis in Inner Mongolia, China.

    Science.gov (United States)

    Wei, Binggan; Yu, Jiangping; Li, Hairong; Yang, Linsheng; Xia, Yajuan; Wu, Kegong; Gao, Jianwei; Guo, Zhiwei; Cui, Na

    2016-04-01

    More than 0.3 million individuals are subject to chronic exposure to arsenic via their drinking water in Inner Mongolia, China. To determine arsenic methylation capacity profiles for such individuals, concentrations of urinary arsenic metabolites were measured for 548 subjects using high-performance liquid chromatography and a hydride generator combined with inductively coupled plasma-mass spectrometry. Mean urinary concentrations of dimethylarsonic acid (DMA), monomethylarsonic acid (MMA), inorganic arsenic (iAs), and total arsenic (TAs) were 200.50, 46.71, 52.96, and 300.17 μg/L, respectively. The %iAs, %DMA, and %MMA were 15.98, 69.72, and 14.29%. Mean urinary %iAs and %MMA were higher in males, while urinary %DMA was higher in females. There was a strong positive correlation between %iAs and %MMA, with negative correlations between %iAs and %DMA, and %iAs and %MMA. In addition, %iAs and %MMA were positively associated with total arsenic in drinking water (WAs), while %DMA was negatively related with WAs. Regression analysis indicated that the primary methylation index (PMI) and secondary methylation index (SMI) generally decreased with increasing WAs. Females had a higher arsenic methylation capacity compared to males. Younger subjects had lower primary arsenic methylation capacity. However, the secondary arsenic methylation capacity was hardly affected by age. Moreover, both primary and secondary arsenic methylation capacities were negatively related to WAs. PMID:26335574

  19. Changes in serum thioredoxin among individuals chronically exposed to arsenic in drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuanyuan; Gao, Yanhui; Zhao, Lijun [Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province and Ministry of Health (23618104), Harbin 150081 (China); Wei, Yudan [Department of Community Medicine, Mercer University School of Medicine, Macon 31207, GA (United States); Feng, Hongqi; Wang, Cheng; Wei, Wei; Ding, Yunpeng [Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province and Ministry of Health (23618104), Harbin 150081 (China); Sun, Dianjun, E-mail: hrbmusdj@163.com [Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Key Lab of Etiology and Epidemiology, Education Bureau of Hei Long Jiang Province and Ministry of Health (23618104), Harbin 150081 (China)

    2012-02-15

    It is well known that oxidative damage plays a key role in the development of chronic arsenicosis. There is a complex set of mechanisms of redox cycling in vivo to protect cells from the damage. In this study, we examined the differences in the levels of serum thioredoxin1 (TRX1) among individuals exposed to different levels of arsenic in drinking water and detected early biomarkers of arsenic poisoning before the appearance of skin lesions. A total of 157 subjects from endemic regions of China were selected and divided into arsenicosis group with skin lesions (total intake of arsenic: 8.68–45.71 mg-year) and non-arsenicosis group without skin lesions, which further divided into low (0.00–1.06 mg-year), medium (1.37–3.55 mg-year), and high (4.26–48.13 mg-year) arsenic exposure groups. Concentrations of serum TRX1 were analyzed by an ELISA method. Levels of water arsenic and urinary speciated arsenics, including inorganic arsenic (iAs), monomethylated arsenic (MMA), and dimethylated arsenic (DMA), were determined by hydride generation atomic absorption spectrometry. Our results showed that the levels of serum TRX1 in arsenicosis patients were significantly higher than that of the subjects who were chronically exposed to arsenic, but without skin lesions. A positive correlation was seen between the levels of serum TRX1 and the total water arsenic intake or the levels of urinary arsenic species. The results of this study indicate that arsenic exposure could significantly change the levels of human serum TRX1, which can be detected before arsenic-specific dermatological symptoms occur. This study provides further evidence on revealing the mechanism of arsenic toxicity. -- Highlights: ► Three regions are selected as the areas affected by endemic arsenicosis of China. ► We first examine changes in serum TRX1 among individuals exposed to arsenic. ► A positive correlation was seen between serum TRX1 and total water arsenic intake. ► The same relationship

  20. Automated determinations of selenium in thermal power plant wastewater by sequential hydride generation and chemiluminescence detection.

    Science.gov (United States)

    Ezoe, Kentaro; Ohyama, Seiichi; Hashem, Md Abul; Ohira, Shin-Ichi; Toda, Kei

    2016-02-01

    After the Fukushima disaster, power generation from nuclear power plants in Japan was completely stopped and old coal-based power plants were re-commissioned to compensate for the decrease in power generation capacity. Although coal is a relatively inexpensive fuel for power generation, it contains high levels (mgkg(-1)) of selenium, which could contaminate the wastewater from thermal power plants. In this work, an automated selenium monitoring system was developed based on sequential hydride generation and chemiluminescence detection. This method could be applied to control of wastewater contamination. In this method, selenium is vaporized as H2Se, which reacts with ozone to produce chemiluminescence. However, interference from arsenic is of concern because the ozone-induced chemiluminescence intensity of H2Se is much lower than that of AsH3. This problem was successfully addressed by vaporizing arsenic and selenium individually in a sequential procedure using a syringe pump equipped with an eight-port selection valve and hot and cold reactors. Oxidative decomposition of organoselenium compounds and pre-reduction of the selenium were performed in the hot reactor, and vapor generation of arsenic and selenium were performed separately in the cold reactor. Sample transfers between the reactors were carried out by a pneumatic air operation by switching with three-way solenoid valves. The detection limit for selenium was 0.008 mg L(-1) and calibration curve was linear up to 1.0 mg L(-1), which provided suitable performance for controlling selenium in wastewater to around the allowable limit (0.1 mg L(-1)). This system consumes few chemicals and is stable for more than a month without any maintenance. Wastewater samples from thermal power plants were collected, and data obtained by the proposed method were compared with those from batchwise water treatment followed by hydride generation-atomic fluorescence spectrometry. PMID:26653491

  1. Determination of arsenic metabolic complex excreted in human urine after administration of sodium 2,3-dimercapto-1-propane sulfonate.

    Science.gov (United States)

    Gong, Zhilong; Jiang, Guifeng; Cullen, William R; Aposhian, H Vasken; Le, X Chris

    2002-10-01

    Sodium 2,3-dimercapto-1-propane sulfonate (DMPS) has been used to treat acute arsenic poisoning. Presumably DMPS functions by chelating some arsenic species to increase the excretion of arsenic from the body. However, the excreted complex of DMPS with arsenic has not been detected. Here we describe a DMPS complex with monomethylarsonous acid (MMA(III)), a key trivalent arsenic in the arsenic methylation process, and show the presence of the DMPS-MMA(III) complex in human urine after the administration of DMPS. The DMPS-MMA(III) complex was characterized using electrospray tandem mass spectrometry and determined by using HPLC separation with hydride generation atomic fluorescence detection (HGAFD). The DMPS-MMA(III) complex did not form a volatile hydride with borohydride treatment. On-line digestion with 0.1 M sodium hydroxide following HPLC separation decomposed the DMPS-MMA(III) complex and allowed for the subsequent quantification by hydride generation atomic fluorescence. Arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA(V)), dimethylarsinic acid (DMA(V)), MMA(III), and DMPS-MMA(III) complex were analyzed in urine samples from human subjects collected after the ingestion of 300 mg of DMPS. The administration of DMPS resulted in a decrease of the DMA(V) concentration and an increase of the MMA(V) concentration excreted in the urine, confirming the previous results. The finding of the DMPS-MMA(III) complex in human urine after DMPS treatment provides an explanation for the inhibition of arsenic methylation by DMPS. Because MMA(III) is the substrate for the biomethylation of arsenic from MMA(V) to DMA(V), the formation of DMPS-MMA(III) complex would reduce the availability of MMA(III) for the subsequent biomethylation. PMID:12387631

  2. Determination of arsenic leaching from glazed and non-glazed Turkish traditional earthenware

    Energy Technology Data Exchange (ETDEWEB)

    Henden, Emur, E-mail: emur.henden@ege.edu.tr; Cataloglu, Rengin; Aksuner, Nur

    2011-07-01

    Glazed and non-glazed earthenware is traditionally and widely used in Turkey and most of the Mediterranean and the Middle East countries for cooking and conservation of foodstuff. Acid-leaching tests have been carried out to determine whether the use of glazed and non-glazed earthenware may constitute a human health hazard risk to the consumers. Earthenware was leached with 4% acetic acid and 1% citric acid solutions, and arsenic in the leachates was measured using hydride generation atomic absorption spectrometry. Arsenic concentrations in the leach solution of non-glazed potteries varied from 30.9 to 800 {mu}g L{sup -1}, while the glazed potteries varied generally from below the limit of detection (0.5 {mu}g L{sup -1}) to 30.6 {mu}g L{sup -1}, but in one poorly glazed series it reached to 110 {mu}g L{sup -1}. Therefore, the risk of arsenic poisoning by poorly glazed and non-glazed potteries is high enough to be of concern. It appears that this is the first study reporting arsenic release from earthenware into food. - Research highlights: {yields} Non-glazed and poorly glazed earthenware may cause a serious arsenic release into food, and drinking water. {yields} Good glazing can avoid or greatly reduce arsenic leaching into food. {yields} Leaching of arsenic from earthenware may cause serious health risk. {yields} This is a pioneering work showing arsenic risk due to earthenware.

  3. Arsenic Trioxide Injection

    Science.gov (United States)

    Arsenic trioxide is used to treat acute promyelocytic leukemia (APL; a type of cancer in which there ... worsened following treatment with other types of chemotherapy. Arsenic trioxide is in a class of medications called ...

  4. Cryptic exposure to arsenic.

    Science.gov (United States)

    Rossy, Kathleen M; Janusz, Christopher A; Schwartz, Robert A

    2005-01-01

    Arsenic is an odorless, colorless and tasteless element long linked with effects on the skin and viscera. Exposure to it may be cryptic. Although human intake can occur from four forms, elemental, inorganic (trivalent and pentavalent arsenic) and organic arsenic, the trivalent inorganic arsenicals constitute the major human hazard. Arsenic usually reaches the skin from occupational, therapeutic, or environmental exposure, although it still may be employed as a poison. Occupations involving new technologies are not exempt from arsenic exposure. Its acute and chronic effects are noteworthy. Treatment options exist for arsenic-induced pathology, but prevention of toxicity remains the main focus. Vitamin and mineral supplementation may play a role in the treatment of arsenic toxicity.

  5. Cryptic exposure to arsenic

    Directory of Open Access Journals (Sweden)

    Rossy Kathleen

    2005-01-01

    Full Text Available Arsenic is an odorless, colorless and tasteless element long linked with effects on the skin and viscera. Exposure to it may be cryptic. Although human intake can occur from four forms, elemental, inorganic (trivalent and pentavalent arsenic and organic arsenic, the trivalent inorganic arsenicals constitute the major human hazard. Arsenic usually reaches the skin from occupational, therapeutic, or environmental exposure, although it still may be employed as a poison. Occupations involving new technologies are not exempt from arsenic exposure. Its acute and chronic effects are noteworthy. Treatment options exist for arsenic-induced pathology, but prevention of toxicity remains the main focus. Vitamin and mineral supplementation may play a role in the treatment of arsenic toxicity.

  6. Arsenic: the forgotten poison?

    Science.gov (United States)

    Barton, E N; Gilbert, D T; Raju, K; Morgan, O S

    1992-03-01

    Chronic arsenic poisoning is an uncommon cause of peripheral neuropathy in Jamaica. A patient with this disorder is described. The insidious nature of chronic arsenic poisoning, with its disabling complications, is emphasised.

  7. Arsenic pollution sources.

    Science.gov (United States)

    Garelick, Hemda; Jones, Huw; Dybowska, Agnieszka; Valsami-Jones, Eugenia

    2008-01-01

    Arsenic is a widely dispersed element in the Earth's crust and exists at an average concentration of approximately 5 mg/kg. There are many possible routes of human exposure to arsenic from both natural and anthropogenic sources. Arsenic occurs as a constituent in more than 200 minerals, although it primarily exists as arsenopyrite and as a constituent in several other sulfide minerals. The introduction of arsenic into drinking water can occur as a result of its natural geological presence in local bedrock. Arsenic-containing bedrock formations of this sort are known in Bangladesh, West Bengal (India), and regions of China, and many cases of endemic contamination by arsenic with serious consequences to human health are known from these areas. Significant natural contamination of surface waters and soil can arise when arsenic-rich geothermal fluids come into contact with surface waters. When humans are implicated in causing or exacerbating arsenic pollution, the cause can almost always be traced to mining or mining-related activities. Arsenic exists in many oxidation states, with arsenic (III) and (V) being the most common forms. Similar to many metalloids, the prevalence of particular species of arsenic depends greatly on the pH and redox conditions of the matrix in which it exists. Speciation is also important in determining the toxicity of arsenic. Arsenic minerals exist in the environment principally as sulfides, oxides, and phosphates. In igneous rocks, only those of volcanic origin are implicated in high aqueous arsenic concentrations. Sedimentary rocks tend not to bear high arsenic loads, and common matrices such as sands and sandstones contain lower concentrations owing to the dominance of quartz and feldspars. Groundwater contamination by arsenic arises from sources of arsenopyrite, base metal sulfides, realgar and orpiment, arsenic-rich pyrite, and iron oxyhydroxide. Mechanisms by which arsenic is released from minerals are varied and are accounted for by

  8. 植物源食品中总砷和无机砷的分布浅析%Analysis of Distribution of Total Arsenic and Inorganic Arsenic in Plant Derived Foods

    Institute of Scientific and Technical Information of China (English)

    梁润; 潘红红; 陈代伟

    2012-01-01

    砷化合物在人体内有蓄积作用,能引起急性或慢性中毒。生物体内的砷主要是有机砷,而砷的致毒性和致癌作用主要取决于无机砷的含量。在食品污染物限量标准中,将砷作为非有意添加的污染物,并规定了不同食品的总砷或无机砷限量标准。本文采用氢化物原子荧光光谱法测定植物源食品中的总砷和无机砷含量,讨论了总砷和无机砷在不同植物源食品中的分布。这有助于我们了解不同种类植物对砷的富集能力。%Accumulation of arsenic compounds can cause acute or chronic poisoning.Arsenic in organism was mainly organic arsenic.The arsenic toxicity and Carcinogenicity mainly depend on the content of inorganic arsenic.Arsenic as a non-intentionally addition of pollutants,the maximum levels of total arsenic or inorganic arsenic were defined in various foods.Hydride Generation-Atomic Fluorescence Spectrometry(HG-AFS) was adopted to determine the total arsenic and inorganic arsenic in plant derived foods.The distribution character of total arsenic and inorganic arsenic in different plant derived foods were discussed,which would help to understand the arsenic accumulation ability of different plants.

  9. SPE HG-AAS method for the determination of inorganic arsenic in rice—results from method validation studies and a survey on rice products

    DEFF Research Database (Denmark)

    Rasmussen, Rie Romme; Qian, Yiting; Sloth, Jens Jørgen

    2013-01-01

    The present paper describes the development, validation and application of a method for inorganic arsenic (iAs) determination in rice samples. The separation of iAs from organoarsenic compounds was done by off-line solid-phase extraction (SPE) followed by hydride generation atomic absorption spec...

  10. Arsenic methylation capability and hypertension risk in subjects living in arseniasis-hyperendemic areas in southwestern Taiwan

    International Nuclear Information System (INIS)

    Background: Cumulative arsenic exposure (CAE) from drinking water has been shown to be associated with hypertension in a dose-response pattern. This study further explored the association between arsenic methylation capability and hypertension risk among residents of arseniasis-hyperendemic areas in Taiwan considering the effect of CAE and other potential confounders. Method: There were 871 subjects (488 women and 383 men) and among them 372 were diagnosed as having hypertension based on a positive history or measured systolic blood pressure ≥ 140 mm Hg and/or diastolic blood pressure ≥ 90 mm Hg. Urinary arsenic species were determined by high-performance liquid chromatography-hydride generator and atomic absorption spectrometry. Primary arsenic methylation index [PMI, defined as monomethylarsonic acid (MMAV) divided by (AsIII + AsV)] and secondary arsenic methylation index (SMI, defined as dimethylarsinic acid divided by MMAV) were used as indicators for arsenic methylation capability. Results: The level of urinary arsenic was still significantly correlated with cumulative arsenic exposure (CAE) calculated from a questionnaire interview (p = 0.02) even after the residents stopped drinking the artesian well water for 2-3 decades. Hypertensive subjects had higher percentages of MMAV and lower SMI than subjects without hypertension. However, subjects having CAE > 0 mg/L-year had higher hypertension risk than those who had CAE = 0 mg/L-year disregard a high or low methylation index. Conclusion: Inefficient arsenic methylation ability may be related with hypertension risk

  11. A Study on the Radial Hydride Assisted Delayed Hydride Cracking of Zircaloy

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jin-Ho; Lee, Ji-Min; Kim, Yong-Soo [Hanyang University, Seoul (Korea, Republic of)

    2015-05-15

    Extensive studies have been done on understanding of DHC(Delayed hydride cracking) phenomenon since several zirconium alloy pressure tubes failed in nuclear reactor in the 1970s. Recently, long-term dry storage strategy has been considered seriously in order to manage spent nuclear fuel in Korea and other countries around the world. Consequentially, many researches have been investigated the degradation mechanisms which will threaten the spent fuel integrity during dry storage and showed that hydrogen related phenomenon such as hydride reorientation and DHC are the critical factors. Especially, DHC is the direct cracking mechanism which can cause not only a through-wall defect but also a radiation leak to the environment. In addition, DHC can be enhanced by radial hydride as reported by Kim who demonstrate that radial hydrides clearly act as crack linkage path. This phenomenon is known as the radial hydride assisted DHC (RHA-DHC). Therefore, study on DHC is essential to ensure the safety of spent fuel. Finite element analysis will be carried out for the stress gradient evaluation around notch tip. A variation in thermal cycle which leads to change in hydrogen solid solution trajectory may be required. If the radial hydride precipitates at notch tip, we will investigate what conditions should be met. Ultimately, we will suggest the regulation criteria for long-term dry storage of spent nuclear fuel.

  12. Computational study of metal hydride cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Satheesh, A.; Muthukumar, P.; Dewan, Anupam [Department of Mechanical Engineering, Indian Institute of Technology, Guwahati, Guwahati 781039 (India)

    2009-04-15

    A computational study of a metal hydride cooling system working with MmNi{sub 4.6}Al{sub 0.4}/MmNi{sub 4.6}Fe{sub 0.4} hydride pair is presented. The unsteady, two-dimensional mathematical model in an annular cylindrical configuration is solved numerically for predicting the time dependent conjugate heat and mass transfer characteristics between coupled reactors. The system of equations is solved by the fully implicit finite volume method (FVM). The effects of constant and variable wall temperature boundary conditions on the reaction bed temperature distribution, hydrogen concentration, and equilibrium pressures of the reactors are investigated. A dynamic correlation of the pressure-concentration-temperature plot is presented. At the given operating temperatures of 363/298/278 K (T{sub H}/T{sub M}/T{sub C}), the cycle time for the constant and variable wall temperature boundary conditions of a single-stage and single-effect metal hydride system are found to be 1470.0 s and 1765.6 s, respectively. The computational results are compared with the experimental data reported in the literature for LaNi{sub 4.61}Mn{sub 0.26}Al{sub 0.13}/La{sub 0.6}Y{sub 0.4}Ni{sub 4.8}Mn{sub 0.2} hydride pair and a good agreement between the two was observed. (author)

  13. The electrochemical impedance of metal hydride electrodes

    DEFF Research Database (Denmark)

    Valøen, Lars Ole; Lasia, Andrzej; Jensen, Jens Oluf;

    2002-01-01

    The electrochemical impedance responses for different laboratory type metal hydride electrodes were successfully modeled and fitted to experimental data for AB5 type hydrogen storage alloys as well as one MgNi type electrode. The models fitted the experimental data remarkably well. Several AC equ...

  14. Arsenic compounds toxic to rice

    Energy Technology Data Exchange (ETDEWEB)

    Epps, E.A.; Sturgis, M.B.

    1939-01-01

    A study has been made of the kinds of arsenic compounds that may be toxic to rice and of means for correcting the toxicity. Some of the arsenic compounds in flooded soils are reduced, with consequent increase in soluble arsenic content of the soil and decrease in total arsenic content due to liberation of gaseous compounds of arsenic. It was demonstrated that some of the arsenic was lost as arsine. Many of the naturally-occurring compounds of arsenic are not attacked by the micro-organisms and do not become more soluble. Additions of sulfur to soils containing toxic amounts of arsenic decreased the amount of soluble arsenic in the soil.

  15. Arsenic cardiotoxicity: An overview.

    Science.gov (United States)

    Alamolhodaei, Nafiseh Sadat; Shirani, Kobra; Karimi, Gholamreza

    2015-11-01

    Arsenic, a naturally ubiquitous element, is found in foods and environment. Cardiac dysfunction is one of the major causes of morbidity and mortality in the world. Arsenic exposure is associated with various cardiopathologic effects including ischemia, arrhythmia and heart failure. Possible mechanisms of arsenic cardiotoxicity include oxidative stress, DNA fragmentation, apoptosis and functional changes of ion channels. Several evidences have shown that mitochondrial disruption, caspase activation, MAPK signaling and p53 are the pathways for arsenic induced apoptosis. Arsenic trioxide is an effective and potent antitumor agent used in patients with acute promyelocytic leukemia and produces dramatic remissions. As2O3 administration has major limitations such as T wave changes, QT prolongation and sudden death in humans. In this review, we discuss the underlying pathobiology of arsenic cardiotoxicity and provide information about cardiac health effects associated with some medicinal plants in arsenic toxicity.

  16. Arsenic removal from water

    Science.gov (United States)

    Moore, Robert C.; Anderson, D. Richard

    2007-07-24

    Methods for removing arsenic from water by addition of inexpensive and commonly available magnesium oxide, magnesium hydroxide, calcium oxide, or calcium hydroxide to the water. The hydroxide has a strong chemical affinity for arsenic and rapidly adsorbs arsenic, even in the presence of carbonate in the water. Simple and commercially available mechanical methods for removal of magnesium hydroxide particles with adsorbed arsenic from drinking water can be used, including filtration, dissolved air flotation, vortex separation, or centrifugal separation. A method for continuous removal of arsenic from water is provided. Also provided is a method for concentrating arsenic in a water sample to facilitate quantification of arsenic, by means of magnesium or calcium hydroxide adsorption.

  17. Environmental Source of Arsenic Exposure

    OpenAIRE

    Chung, Jin-Yong; Yu, Seung-Do; Hong, Young-Seoub

    2014-01-01

    Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a ...

  18. Hydrogen storage in metallic hydrides: the hydrides of magnesium-nickel alloys

    International Nuclear Information System (INIS)

    The massive and common use of hydrogen as an energy carrier requires an adequate solution to the problem of storing it. High pressure or low temperatures are not entirely satisfactory, having each a limited range of applications. Reversible metal hydrides cover a range of applications intermediate to high pressure gas and low temperature liquid hydrogen, retaining very favorable safety and energy density characteristics, both for mobile and stationary applications. This work demonstrates the technical viability of storing hydrogen in metal hydrides of magnesium-nickel alloys. Also, it shows that technology, a product of science, can be generated within an academic environment, of the goal is clear, the demand outstanding and the means available. We review briefly theoretical models relating to metal hydride properties, specially the thermodynamics properties relevant to this work. We report our experimental results on hydrides of magnesium-nickel alloys of various compositions including data on structure, hydrogen storage capacities, reaction kinetics, pressure-composition isotherms. We selected a promising alloy for mass production, built and tested a modular storage tank based on the hydrides of the alloy, with a capacity for storing 10 Nm sup(3) of hydrogen of 1 atm and 20 sup(0)C. The tank weighs 46,3 Kg and has a volume of 21 l. (author)

  19. SANS Measurement of Hydrides in Uranium

    International Nuclear Information System (INIS)

    SANS scattering is shown to be an effective method for detecting the presence of hydrogen precipitates in uranium. High purity polycrystalline samples of depleted uranium were given several hydriding treatments which included extended exposures to hydrogen gas at two different pressures at 630 C as well as a furnace anneal at 850 C followed by slow cooling in the near absence hydrogen gas. All samples exhibited neutron scattering that was in proportion to the expected levels of hydrogen content. While the scattering signal was strong, the shape of the scattering curve indicated that the scattering objects were large sized objects. Only by use of a very high angular resolution SANS technique was it possible to make estimates of the major diameter of the scattering objects. This analysis permits an estimate of the volume fraction and means size of the hydride precipitates in uranium

  20. Field cryofocussing hydride generation applied to the simultaneous multi-elemental determination of alkyl-metal(loid) species in natural waters using ICP-MS detection.

    Science.gov (United States)

    Tseng, C M; Amouroux, D; Brindle, I D; Donard, O F

    2000-12-01

    Two hydride generation manifold systems, utilizing flow injection and cryotrapping techniques for alkyl-metal(loid) speciation analysis in natural waters, are described in this paper. They provide shipboard capacity for simultaneous derivatization of analytes with NaBH4 and cryotrapping of the generated products in a field packed column at -196 degrees C. The first system is a large-volume hydride generator, using a reagent-injection flow technique as a flow batch type, that has been fully optimized and applied to the simultaneous detection of alkylated species in estuarine waters. The technique permits the analysis of a large volume sample (0.5-11) at a sampling rate of 3 h-1. The second is an online continuous flow hydride generator. A sampling rate of 3-12 h-1 can be achieved with samples of 0.1-0.51. In addition, shipboard operation eliminates major problems related to sample pretreatment, transport and storage. Ultra-trace multi-element determination is finally performed in the laboratory by cryogenic GC hyphenated with ICP-MS. Routine detection limits of 0.5-10 pg (as metal) for 0.51 water samples were achieved for the selected alkyl-metal(loid) species of arsenic, germanium, mercury and tin. Concentrations of various species, obtained from water samples taken from the Rhine estuary, are also presented. These species include alkylated arsenic compounds, other than methyl derivatives, that have been tentatively identified and are reported here for the first time.

  1. Metal hydrides based high energy density thermal battery

    International Nuclear Information System (INIS)

    Highlights: • The principle of the thermal battery using advanced metal hydrides was demonstrated. • The thermal battery used MgH2 and TiMnV as a working pair. • High energy density can be achieved by the use of MgH2 to store thermal energy. - Abstract: A concept of thermal battery based on advanced metal hydrides was studied for heating and cooling of cabins in electric vehicles. The system utilized a pair of thermodynamically matched metal hydrides as energy storage media. The pair of hydrides that was identified and developed was: (1) catalyzed MgH2 as the high temperature hydride material, due to its high energy density and enhanced kinetics; and (2) TiV0.62Mn1.5 alloy as the matching low temperature hydride. Further, a proof-of-concept prototype was built and tested, demonstrating the potential of the system as HVAC for transportation vehicles

  2. Arsenic compounds and cancer.

    Science.gov (United States)

    Axelson, O

    1980-01-01

    Exposure to arsenic compounds has been epidemiologically associated with various types of cancers, particularly cancer of the lung among copper smelters and pesticide workers, whereas skin cancers and liver angiosarcomas have been associated with ingestion of arsenic for treatment of skin disorders, especially psoriasis. Attempts to reproduce cancer in animals have been mainly unsuccessful, however. Experimental evidence suggests that arsenic inhibits DNA repair; this might help to explain the somewhat conflicting observations from epidemiologic studies and animal experiments with regard to carcinogenicity, and perhaps also cardiovascular morbidity related to arsenic exposure. PMID:7463514

  3. Levels of total arsenic in edible fish and shellfish obtained from two coastal sectors of the Atacama Desert in the north of Chile: use of non-migratory marine species as bioindicators of sea environmental pollution.

    Science.gov (United States)

    Cornejo-Ponce, Lorena; Lienqueo, Hugo H; Arriaza, Bernardo T

    2011-01-01

    The Camarones (CB) and Vitor (VB) Bays are situated in the middle of Atacama Desert, and their economies are based on activities entirely associated with the extraction of marine produce. The aim of this study was to determine the total arsenic content in three species of fish and seven species of shellfish from these two bays. The quantification of the total arsenic content in these products was performed by Hydride-Generation Atomic Absorption Spectrometry, HG-AAS. The results showed that marine species associated with the CB sector had higher total arsenic levels than the same species in the area of VB, a finding attributed to much higher total arsenic concentrations in the water and soils of CB than VB. The species with the highest total arsenic concentration was the Venus antique (7.50 mg kg (-1)) from the CB, and the lowest total arsenic content was found in Cheilodactylidae variegatus (0.34 mg kg(-1)) from VB. PMID:21879860

  4. METHOD AND APPARATUS FOR MAKING URANIUM-HYDRIDE COMPACTS

    Science.gov (United States)

    Wellborn, W.; Armstrong, J.R.

    1959-03-10

    A method and apparatus are presented for making compacts of pyrophoric hydrides in a continuous operation out of contact with air. It is particularly useful for the preparation of a canned compact of uranium hydride possessing high density and purity. The metallic uranium is enclosed in a container, positioned in a die body evacuated and nvert the uranium to the hydride is admitted and the container sealed. Heat is applied to bring about the formation of the hydride, following which compression is used to form the compact sealed in a container ready for use.

  5. INORGANIC ARSENIC SPECIATION IN THE ATMOSPHERE: STUDY IN ISFAHAN

    Directory of Open Access Journals (Sweden)

    A KALANTARI

    2000-06-01

    Full Text Available Introduction. Arsenic is one of the most hazardous elements that associate with airborne particulate matter in the atmosphere. Among the different species of arsenic, ASIII has the most toxic and carcinogenic property between any other kind of this element. Arsenic speciation is important in environmental studies. Methods. We collected 59 samples of airborne particulate matter from the atmosphere in Isfahan in a three months period by a high volume air sampler with a flow rate of 1 m3 min-1. Air particulates were collected on the paper filter (Whatman No.41. Four different digestive procedures were examined in order to find the best method. At last we chose digestion of filter with HCI (10-4N due to its feasibility, cost benefit and efficacy. Other methods that examined were digestion of filter with a mixture of HN03 and H2O2, with a mixture of HNO3 and H2O2 and with HCI (1 N. The determination of As3+ and As5+ concentrations were performed by hydrIde generation atomic absorption spectrometry. The effect of Ph on the absorption signal was also investigated in arsenic speciation. Results. Average of total saspended particles (TSP in July, August, and September 1998 were 223, 172, and 247 mg.m3 respectively. The recovery of arsenic from airborne particulate matter was almost the same for the different digestion methods. The concentration and volume of NaBH4 was optimized for determining of different species of arsenic. At pH=5, Asv didn't produce any absorption signal. So, the determination of ASm was carried out easilyat the above mentioned pH. The concentrations of total arsenic were determined in 47 samples. The mean concentrations of total arsenic in July, August and September were 3.31, 2.01 and 2.6, respectively. Discussion. More than 50 percent of total atmospheric arsenic exists as ASIII which is the most toxic and carcinogenic forms of this element. So, it is recommended to make a suitable policy for decreasing of this hazardous

  6. Arsenic Speciation and Seasonal Changes in Nutrient Availability and Micro-plankton Abundance in Southampton Water, U.K.

    Science.gov (United States)

    Howard, A. G.; Comber, S. D. W.; Kifle, D.; Antai, E. E.; Purdie, D. A.

    1995-04-01

    . Phosphate depletion did not appear to be a prerequisite for arsenate assimilation. From the summer peak methylated arsenic levels then gradually diminished to undetectable levels in the winter months. Monomethylarsenic, present at concentrations approximately 50% those of dimethylarsenic, persisted longer through the summer. The arsenic species which can be measured using the hydride procedure may therefore represent intermediates in the decomposition of the bioarsenicals, such as arsenosugars, which are released, either actively as excretion/secretion products or passively as part of the decay process. Currently unidentified precursors of hydride-reducible arsenic species (' hidden ' arsenic) may explain the poor link between planktonic activity and the levels of measurable arsenic species in the water column.

  7. IMEP-32: Determination of inorganic arsenic in animal feed of marine origin

    DEFF Research Database (Denmark)

    Sloth, Jens Jørgen; Cordeiro, Fernando; Rasmussen, Rie Romme;

    Parliament and the Council on undesirable substances in animal feed [1] where it is indicated that "Upon request of the competent authorities, the responsible operator must perform an analysis to demonstrate that the content of inorganic arsenic is lower than 2 ppm". The method is based on solid phase......A collaborative study, IMEP-32, was conducted in accordance with international protocols to determine the performance characteristics of an analytical method for the determination of inorganic arsenic in animal feed of marine origin. The method would support Directive No 2002/32/EC of the European...... extraction (SPE) separation of inorganic arsenic from organoarsenic compounds followed by detection with hydride generation atomic absorption spectrometry (HG-AAS). The collaborative study investigated different types of samples of marine origin, including complete feed (unspiked and spiked), fish meal...

  8. Seasonal Variation of Arsenic Concentration in Ground Water of Nawalparasi District of Nepal

    Directory of Open Access Journals (Sweden)

    Rajib Kumar Shrestha

    2014-03-01

    Full Text Available Ground water of southern part of Nepal, also known as Terai region where population density is relatively very high, has been contaminated with poisonous element Arsenic. This study has been carried out to determine variability of the level of arsenic contamination in groundwater with seasons of Pathkhauli village of Devgaun VDC and Mahuwa village of Manari VDC in Nawalparasi district, the western Terai district. Hydride Generation Atomic Absorption Spectrophotometer (HG-AAS and UV-visible Spectrophotometry was used for analysis. Total 55 groundwater samples in post-monsoon season and 45 groundwater samples in pre-monsoon season were collected. The level of arsenic contamination in groundwater was found above the Nepal interim standard of 50 ppb. Of the total 42 water samples from each pre- and post- monsoon seasons analyzed, 28 water samples (67.67% showed higher As-concentration in pre-monsoon season.

  9. Ambient-Temperature Trap/Release of Arsenic by Dielectric Barrier Discharge and Its Application to Ultratrace Arsenic Determination in Surface Water Followed by Atomic Fluorescence Spectrometry.

    Science.gov (United States)

    Mao, Xuefei; Qi, Yuehan; Huang, Junwei; Liu, Jixin; Chen, Guoying; Na, Xing; Wang, Min; Qian, Yongzhong

    2016-04-01

    A novel dielectric barrier discharge reactor (DBDR) was utilized to trap/release arsenic coupled to hydride generation atomic fluorescence spectrometry (HG-AFS). On the DBD principle, the precise and accurate control of trap/release procedures was fulfilled at ambient temperature, and an analytical method was established for ultratrace arsenic in real samples. Moreover, the effects of voltage, oxygen, hydrogen, and water vapor on trapping and releasing arsenic by DBDR were investigated. For trapping, arsenic could be completely trapped in DBDR at 40 mL/min of O2 input mixed with 600 mL/min Ar carrier gas and 9.2 kV discharge potential; prior to release, the Ar carrier gas input should be changed from the upstream gas liquid separator (GLS) to the downstream GLS and kept for 180 s to eliminate possible water vapor interference; for arsenic release, O2 was replaced by 200 mL/min H2 and discharge potential was adjusted to 9.5 kV. Under optimized conditions, arsenic could be detected as low as 1.0 ng/L with an 8-fold enrichment factor; the linearity of calibration reached R(2) > 0.995 in the 0.05 μg/L-5 μg/L range. The mean spiked recoveries for tap, river, lake, and seawater samples were 98% to 103%; and the measured values of the CRMs including GSB-Z50004-200431, GBW08605, and GBW(E)080390 were in good agreement with the certified values. These findings proved the feasibility of DBDR as an arsenic preconcentration tool for atomic spectrometric instrumentation and arsenic recycling in industrial waste gas discharge. PMID:26976077

  10. Protective effects of plasma alpha-tocopherols on the risk of inorganic arsenic-related urothelial carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chi-Jung [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, Taipei, Taiwan (China); Chen, Ying-Ting [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Su, Chien-Tien [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Wu, Chia-Chang [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Urology, Taipei Medical Universtiy-Shuang Ho Hospital, Taipei, Taiwan (China); Shiue, Horng-Sheng [Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (China); Huang, Chao-Yuan [Department of Urology, National Taiwan University Hospital, Taipei, Taiwan (China); Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2011-02-15

    Arsenic plays an important role in producing oxidative stress in cultured cells. To investigate the interaction between high oxidative stress and low arsenic methylation capacity on arsenic carcinogenesis, a case-control study was conducted to evaluate the relationship among the indices of oxidative stress, such as urinary 8-hydroxydeoxyquanine (8-OHdG), as well as plasma micronutrients and urinary arsenic profiles on urothelial carcinoma (UC) risk. Urinary 8-OHdG was measured using high-sensitivity enzyme-linked immunosorbent assay kits. The urinary arsenic species were analyzed using high-performance liquid chromatography and hydride generator-atomic absorption spectrometry. Plasma micronutrient levels were analyzed using reversed-phase high-performance liquid chromatography. The present study showed a significant protective effect of plasma alpha-tocopherol on UC risk. Plasma alpha-tocopherol levels were significantly inversely related to urinary total arsenic concentrations and inorganic arsenic percentage (InAs%), and significantly positively related to dimethylarsinic acid percentage (DMA%). There were no correlations between plasma micronutrients and urinary 8-OHdG. Study participants with lower alpha-tocopherol and higher urinary total arsenic, higher InAs%, higher MMA%, and lower DMA% had a higher UC risk than those with higher alpha-tocopherol and lower urinary total arsenic, lower InAs%, lower MMA%, and higher DMA%. These results suggest that plasma alpha-tocopherol might modify the risk of inorganic arsenic-related UC. - Research Highlights: {yields} Plasma alpha-tocopherol levels were significantly inversely related to UC risk. {yields} There were no correlations between plasma micronutrients and urinary 8-OHdG. {yields} People with lower alpha-tocopherol and higher total arsenic had increased UC risk.

  11. Protective effects of plasma alpha-tocopherols on the risk of inorganic arsenic-related urothelial carcinoma

    International Nuclear Information System (INIS)

    Arsenic plays an important role in producing oxidative stress in cultured cells. To investigate the interaction between high oxidative stress and low arsenic methylation capacity on arsenic carcinogenesis, a case-control study was conducted to evaluate the relationship among the indices of oxidative stress, such as urinary 8-hydroxydeoxyquanine (8-OHdG), as well as plasma micronutrients and urinary arsenic profiles on urothelial carcinoma (UC) risk. Urinary 8-OHdG was measured using high-sensitivity enzyme-linked immunosorbent assay kits. The urinary arsenic species were analyzed using high-performance liquid chromatography and hydride generator-atomic absorption spectrometry. Plasma micronutrient levels were analyzed using reversed-phase high-performance liquid chromatography. The present study showed a significant protective effect of plasma alpha-tocopherol on UC risk. Plasma alpha-tocopherol levels were significantly inversely related to urinary total arsenic concentrations and inorganic arsenic percentage (InAs%), and significantly positively related to dimethylarsinic acid percentage (DMA%). There were no correlations between plasma micronutrients and urinary 8-OHdG. Study participants with lower alpha-tocopherol and higher urinary total arsenic, higher InAs%, higher MMA%, and lower DMA% had a higher UC risk than those with higher alpha-tocopherol and lower urinary total arsenic, lower InAs%, lower MMA%, and higher DMA%. These results suggest that plasma alpha-tocopherol might modify the risk of inorganic arsenic-related UC. - Research Highlights: → Plasma alpha-tocopherol levels were significantly inversely related to UC risk. → There were no correlations between plasma micronutrients and urinary 8-OHdG. → People with lower alpha-tocopherol and higher total arsenic had increased UC risk.

  12. Preservation procedures for arsenic speciation in a stream affected by acid mine drainage in southwestern Spain.

    Science.gov (United States)

    Sánchez-Rodas, Daniel; Oliveira, Vanesa; Sarmiento, Aguasanta M; Gómez-Ariza, José Luis; Nieto, José Miguel

    2006-04-01

    A preservation study has been performed for arsenic speciation in surface freshwaters affected by acid mine drainage (AMD), a pollution source characterized by low pH and high metallic content. Two sample preservation procedures described in the literature were attempted using opaque glass containers and refrigeration: i) addition of 0.25 mol L(-1) EDTA to the samples, which maintained the stability of the arsenic species for 3 h; and ii) in situ sample clean-up with a cationic exchange resin, in order to reduce the metallic load, which resulted in a partial co-adsorption of arsenic onto Fe precipitates. A new proposed method was also tried: sample acidification with 6 mol L(-1) HCl followed by in situ clean-up with a cationic exchange resin, which allowed a longer preservation time of at least 48 h. The proposed method was successfully applied to water samples with high arsenic content, taken from the Aguas Agrias Stream (Odiel River Basin, SW Spain), which is severely affected by AMD that originates at the nearby polymetallic sulfide mine of Tharsis. The speciation results obtained by liquid chromatography-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS) indicated that during the summer the main arsenic species was As(V) at the hundred microg L(-1) level, followed by DMA (dimethyl arsenic) and As(III) below the ten microg L(-1) level. In winter, As(V) and As(III) increased at least fivefold, whereas the DMA was not detected.

  13. Arsenic poisoning in cattle

    Energy Technology Data Exchange (ETDEWEB)

    Reagor, J.C.

    Reports of heavy metal intoxication submitted to the Texas Veterinary Medical Diagnostic Laboratory indicate that arsenic is the most common heavy metal intoxicant in Texas. The most frequent sources of arsenic are compounds used as herbicides and cotton defoliants. The misuse of these compounds and subsequent intoxication of cattle is discussed in this paper. 8 references, 1 table.

  14. Arsenic in Food

    Science.gov (United States)

    ... Biologics Animal & Veterinary Cosmetics Tobacco Products Food Home Food Foodborne Illness & Contaminants Metals Arsenic Share Tweet Linkedin Pin it More ... and previous or current use of arsenic-containing pesticides. Are there ... compounds in water, food, air, and soil: organic and inorganic (these together ...

  15. [Acute arsenic poisoning].

    Science.gov (United States)

    Montelescaut, Etienne; Vermeersch, Véronique; Commandeur, Diane; Huynh, Sophie; Danguy des Deserts, Marc; Sapin, Jeanne; Ould-Ahmed, Mehdi; Drouillard, Isabelle

    2014-01-01

    Acute arsenic poisoning is a rare cause of suicide attempt. It causes a multiple organs failure caused by cardiogenic shock. We report the case of a patient admitted twelve hours after an ingestion of trioxide arsenic having survived thanks to a premature treatment.

  16. [Acute arsenic poisoning].

    Science.gov (United States)

    Montelescaut, Etienne; Vermeersch, Véronique; Commandeur, Diane; Huynh, Sophie; Danguy des Deserts, Marc; Sapin, Jeanne; Ould-Ahmed, Mehdi; Drouillard, Isabelle

    2014-01-01

    Acute arsenic poisoning is a rare cause of suicide attempt. It causes a multiple organs failure caused by cardiogenic shock. We report the case of a patient admitted twelve hours after an ingestion of trioxide arsenic having survived thanks to a premature treatment. PMID:25486670

  17. High energy density battery based on complex hydrides

    Science.gov (United States)

    Zidan, Ragaiy

    2016-04-26

    A battery and process of operating a battery system is provided using high hydrogen capacity complex hydrides in an organic non-aqueous solvent that allows the transport of hydride ions such as AlH.sub.4.sup.- and metal ions during respective discharging and charging steps.

  18. Ultra-sonic observation in niobium hydride precipitation

    International Nuclear Information System (INIS)

    The hidrogen embrittlement of exothermic ocluders, had been considered as due to applied stress induced hydride precipitates leading to brittle fracture. The results of simultaneous measurements of macroscopic deformation and elastic change due to hydride precipitation, using the ultrasonic pulse-echo technique are showed. THen it was tested the possibility of kinectis precipitation parameters evoluation. (Author)

  19. Electrochemical and Optical Properties of Magnesium-Alloy Hydrides Reviewed

    Directory of Open Access Journals (Sweden)

    Thirugnasambandam G. Manivasagam

    2012-10-01

    Full Text Available As potential hydrogen storage media, magnesium based hydrides have been systematically studied in order to improve reversibility, storage capacity, kinetics and thermodynamics. The present article deals with the electrochemical and optical properties of Mg alloy hydrides. Electrochemical hydrogenation, compared to conventional gas phase hydrogen loading, provides precise control with only moderate reaction conditions. Interestingly, the alloy composition determines the crystallographic nature of the metal-hydride: a structural change is induced from rutile to fluorite at 80 at.% of Mg in Mg-TM alloy, with ensuing improved hydrogen mobility and storage capacity. So far, 6 wt.% (equivalent to 1600 mAh/g of reversibly stored hydrogen in MgyTM(1-yHx (TM: Sc, Ti has been reported. Thin film forms of these metal-hydrides reveal interesting electrochromic properties as a function of hydrogen content. Optical switching occurs during (dehydrogenation between the reflective metal and the transparent metal hydride states. The chronological sequence of the optical improvements in optically active metal hydrides starts with the rare earth systems (YHx, followed by Mg rare earth alloy hydrides (MgyGd(1-yHx and concludes with Mg transition metal hydrides (MgyTM(1-yHx. In-situ optical characterization of gradient thin films during (dehydrogenation, denoted as hydrogenography, enables the monitoring of alloy composition gradients simultaneously.

  20. Modular hydride beds for mobile applications

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, M.E.; Stewart, K.D.

    1997-08-01

    Design, construction, initial testing and simple thermal modeling of modular, metal hydride beds have been completed. Originally designed for supplying hydrogen to a fuel cell on a mobile vehicle, the complete bed design consists of 8 modules and is intended for use on the Palm Desert Vehicle (PDV) under development at the Schatz Energy Center, Humbolt State University. Each module contains approximately 2 kg of a commercially available, low temperature, hydride-forming metal alloy. Waste heat from the fuel cell in the form of heated water is used to desorb hydrogen from the alloy for supplying feed hydrogen to the fuel cell. In order to help determine the performance of such a modular bed system, six modules were constructed and tested. The design and construction of the modules is described in detail. Initial testing of the modules both individually and as a group showed that each module can store {approximately} 30 g of hydrogen (at 165 PSIA fill pressure, 17 C), could be filled with hydrogen in 6 minutes at a nominal, 75 standard liters/min (slm) fueling rate, and could supply hydrogen during desorption at rates of 25 slm, the maximum anticipated hydrogen fuel cell input requirement. Tests made of 5 modules as a group indicated that the behavior of the group run in parallel both in fueling and gas delivery could be directly predicted from the corresponding, single module characteristics by using an appropriate scaling factor. Simple thermal modeling of a module as an array of cylindrical, hydride-filled tubes was performed. The predictions of the model are in good agreement with experimental data.

  1. Preferred hydride growth orientations on oxide-coated gadolinium surfaces

    International Nuclear Information System (INIS)

    Highlights: ► The preferred hydride growth orientations on gadolinium metal coated by a thin oxide layer are presented. ► A preferred growth of the (1 0 0)h plane of the face centered cubic (FCC) GdH2 is observed for the hydride spots forming below the oxidation layer. ► A change to the (1 1 1)h plane of the cubic hydride dominates for the hydride's Growth Centers. ► The texture change is attributed to the surface normal compressive stress component exerted by the oxidation layer on the developing hydride. - Abstract: The initial development of hydrides on polycrystalline gadolinium (Gd), as on some other hydride forming metals, is characterized by two sequential steps. The first step involves the rapid formation of a dense pattern of small hydride spots (referred to as the “small family” of hydrides) below the native oxidation layer. The second stage takes place when some of the “small family” nucleants (referred to as “growth centers”, GCs) break the oxide layer, leading to their rapid growth and finally to the massive hydriding of the sample. In the present study, the texture of the two hydride families was studied, by combining X-ray diffraction (XRD) analysis with a microscopic analysis of the hydride, using scanning electron microscopy (SEM) and atomic force microscopy (AFM). It has been observed that for the “small family”, a preferred growth of the (1 0 0)h plane of the cubic GdH2 takes place, whereas for the GCs, a change to the (1 1 1)h plane of the cubic hydride dominates. These preferred growth orientations were analyzed by their structure relation with the (0 0 .1)m basal plane of the Gd metal. It has been concluded that the above texture change is due to the surface normal compressive stress component exerted by the oxidation overlayer on the developing hydride, preventing the (0 0 .1)m||(1 1 1)h growth orientation. This stress is relieved upon the rupture of that overlayer and the development of the GCs, leading to the

  2. Low-frequency excitations in zirconium hydrides

    International Nuclear Information System (INIS)

    The slow inelastic neutron scattering (INS) on ZrHx systems (x = 0.38, 0.52) revealed new excitations located within the energy range 2-10 MeV. Besides the acoustic vibrations specific to α-HCP Zr and γ-FCO Zr hydride the fine structure of these excitations is clearly observed. The origin of the new observed peaks is not very clear but a proton tunneling or a resonance effect in α-Zr lattice could be taken into account

  3. Tritium immobilization and packaging using metal hydrides

    International Nuclear Information System (INIS)

    Tritium recovered from CANDU heavy water reactors will have to be packaged and stored in a safe manner. Tritium will be recovered in the elemental form, T2. Metal tritides are effective compounds in which to immobilize the tritium as a stable non-reactive solid with a high tritium capacity. The technology necessary to prepare hydrides of suitable metals, such as titanium and zirconium, have been developed and the properties of the prepared materials evaluated. Conceptual designs of packages for containing metal tritides suitable for transportation and long-term storage have been made and initial testing started. (author)

  4. Metal hydrides for concentrating solar thermal power energy storage

    Science.gov (United States)

    Sheppard, D. A.; Paskevicius, M.; Humphries, T. D.; Felderhoff, M.; Capurso, G.; Bellosta von Colbe, J.; Dornheim, M.; Klassen, T.; Ward, P. A.; Teprovich, J. A.; Corgnale, C.; Zidan, R.; Grant, D. M.; Buckley, C. E.

    2016-04-01

    The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost of concentrating solar thermal power. We focus on the underlying technology that allows metal hydrides to function as thermal energy storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room temperature and as high as 1100 °C. The potential of metal hydrides for thermal storage is explored, while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. The engineering challenges associated with utilising metal hydrides for high-temperature TES are also addressed.

  5. Recent advances in metal hydrides for clean energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Ronnebro, Ewa; Majzoub, Eric H.

    2013-06-01

    Metal hydrides are a fascinating class of materials that can be utilized for a surprising variety of clean energy applications, including smart solar collectors, smart windows, sensors, thermal energy storage, and batteries, in addition to their traditional application for hydrogen storage. Over the past decade, research on metal hydrides for hydrogen storage increased due to global governmental incentives and an increased focus on hydrogen storage research for polymer electrolyte membrane fuel cell operation. Tremendous progress has been made in so-called complex metal hydrides for hydrogen storage applications with the discovery of many new hydrides containing covalently bound complex anions. Many of these materials have applications beyond hydrogen storage and are being investigated for lithium-ion battery separator and anode materials. In this issue of MRS Bulletin , we present the state of the art of key evolving metal-hydride-based clean energy technologies with an outlook toward future needs.

  6. Helium trapping at erbium oxide precipitates in erbium hydride

    Energy Technology Data Exchange (ETDEWEB)

    Foiles, Stephen M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Battaile, Corbett Chandler [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-02-01

    The formation of He bubbles in erbium tritides is a significant process in the aging of these materials. Due to the long-standing uncertainty about the initial nucleation process of these bubbles, there is interest in mechanisms that can lead to the localization of He in erbium hydrides. Previous work has been unable to identify nucleation sites in homogeneous erbium hydride. This work builds on the experimental observation that erbium hydrides have nano- scale erbium oxide precipitates due to the high thermodynamic stability of erbium oxide and the ubiquitous presence of oxygen during materials processing. Fundamental DFT calculations indicate that the He is energetically favored in the oxide relative to the bulk hydride. Activation energies for the motion of He in the oxide and at the oxide-hydride interface indicate that trapping is kinetically feasible. A simple kinetic Monte Carlo model is developed that demonstrates the degree of trapping of He as a function of temperature and oxide fraction.

  7. Results of NDE Technique Evaluation of Clad Hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Dennis C. Kunerth

    2014-09-01

    This report fulfills the M4 milestone, M4FT-14IN0805023, Results of NDE Technique Evaluation of Clad Hydrides, under Work Package Number FT-14IN080502. During service, zirconium alloy fuel cladding will degrade via corrosion/oxidation. Hydrogen, a byproduct of the oxidation process, will be absorbed into the cladding and eventually form hydrides due to low hydrogen solubility limits. The hydride phase is detrimental to the mechanical properties of the cladding and therefore it is important to be able to detect and characterize the presence of this constituent within the cladding. Presently, hydrides are evaluated using destructive examination. If nondestructive evaluation techniques can be used to detect and characterize the hydrides, the potential exists to significantly increase test sample coverage while reducing evaluation time and cost. To demonstrate the viability this approach, an initial evaluation of eddy current and ultrasonic techniques were performed to demonstrate the basic ability to these techniques to detect hydrides or their effects on the microstructure. Conventional continuous wave eddy current techniques were applied to zirconium based cladding test samples thermally processed with hydrogen gas to promote the absorption of hydrogen and subsequent formation of hydrides. The results of the evaluation demonstrate that eddy current inspection approaches have the potential to detect both the physical damage induced by hydrides, e.g. blisters and cracking, as well as the combined effects of absorbed hydrogen and hydride precipitates on the electrical properties of the zirconium alloy. Similarly, measurements of ultrasonic wave velocities indicate changes in the elastic properties resulting from the combined effects of absorbed hydrogen and hydride precipitates as well as changes in geometry in regions of severe degradation. However, for both approaches, the signal responses intended to make the desired measurement incorporate a number of contributing

  8. Binational Arsenic Exposure Survey: Methodology and Estimated Arsenic Intake from Drinking Water and Urinary Arsenic Concentrations

    Science.gov (United States)

    Roberge, Jason; O’Rourke, Mary Kay; Meza-Montenegro, Maria Mercedes; Gutiérrez-Millán, Luis Enrique; Burgess, Jefferey L.; Harris, Robin B.

    2012-01-01

    The Binational Arsenic Exposure Survey (BAsES) was designed to evaluate probable arsenic exposures in selected areas of southern Arizona and northern Mexico, two regions with known elevated levels of arsenic in groundwater reserves. This paper describes the methodology of BAsES and the relationship between estimated arsenic intake from beverages and arsenic output in urine. Households from eight communities were selected for their varying groundwater arsenic concentrations in Arizona, USA and Sonora, Mexico. Adults responded to questionnaires and provided dietary information. A first morning urine void and water from all household drinking sources were collected. Associations between urinary arsenic concentration (total, organic, inorganic) and estimated level of arsenic consumed from water and other beverages were evaluated through crude associations and by random effects models. Median estimated total arsenic intake from beverages among participants from Arizona communities ranged from 1.7 to 14.1 µg/day compared to 0.6 to 3.4 µg/day among those from Mexico communities. In contrast, median urinary inorganic arsenic concentrations were greatest among participants from Hermosillo, Mexico (6.2 µg/L) whereas a high of 2.0 µg/L was found among participants from Ajo, Arizona. Estimated arsenic intake from drinking water was associated with urinary total arsenic concentration (p < 0.001), urinary inorganic arsenic concentration (p < 0.001), and urinary sum of species (p < 0.001). Urinary arsenic concentrations increased between 7% and 12% for each one percent increase in arsenic consumed from drinking water. Variability in arsenic intake from beverages and urinary arsenic output yielded counter intuitive results. Estimated intake of arsenic from all beverages was greatest among Arizonans yet participants in Mexico had higher urinary total and inorganic arsenic concentrations. Other contributors to urinary arsenic concentrations should be evaluated. PMID:22690182

  9. Binational Arsenic Exposure Survey: Methodology and Estimated Arsenic Intake from Drinking Water and Urinary Arsenic Concentrations

    Directory of Open Access Journals (Sweden)

    Robin B. Harris

    2012-03-01

    Full Text Available The Binational Arsenic Exposure Survey (BAsES was designed to evaluate probable arsenic exposures in selected areas of southern Arizona and northern Mexico, two regions with known elevated levels of arsenic in groundwater reserves. This paper describes the methodology of BAsES and the relationship between estimated arsenic intake from beverages and arsenic output in urine. Households from eight communities were selected for their varying groundwater arsenic concentrations in Arizona, USA and Sonora, Mexico. Adults responded to questionnaires and provided dietary information. A first morning urine void and water from all household drinking sources were collected. Associations between urinary arsenic concentration (total, organic, inorganic and estimated level of arsenic consumed from water and other beverages were evaluated through crude associations and by random effects models. Median estimated total arsenic intake from beverages among participants from Arizona communities ranged from 1.7 to 14.1 µg/day compared to 0.6 to 3.4 µg/day among those from Mexico communities. In contrast, median urinary inorganic arsenic concentrations were greatest among participants from Hermosillo, Mexico (6.2 µg/L whereas a high of 2.0 µg/L was found among participants from Ajo, Arizona. Estimated arsenic intake from drinking water was associated with urinary total arsenic concentration (p < 0.001, urinary inorganic arsenic concentration (p < 0.001, and urinary sum of species (p < 0.001. Urinary arsenic concentrations increased between 7% and 12% for each one percent increase in arsenic consumed from drinking water. Variability in arsenic intake from beverages and urinary arsenic output yielded counter intuitive results. Estimated intake of arsenic from all beverages was greatest among Arizonans yet participants in Mexico had higher urinary total and inorganic arsenic concentrations. Other contributors to urinary arsenic concentrations should be evaluated.

  10. Nanoindentation measurements of the mechanical properties of zirconium matrix and hydrides in unirradiated pre-hydrided nuclear fuel cladding

    Science.gov (United States)

    Rico, A.; Martin-Rengel, M. A.; Ruiz-Hervias, J.; Rodriguez, J.; Gomez-Sanchez, F. J.

    2014-09-01

    It is well known that the mechanical properties of the nuclear fuel cladding may be affected by the presence of hydrides. The average mechanical properties of hydrided cladding have been extensively investigated from a macroscopic point of view. In addition, the mechanical and fracture properties of bulk hydride samples fabricated from zirconium plates have also been reported. In this paper, Young's modulus, hardness and yield stress are measured for each phase, namely zirconium hydrides and matrix, of pre-hydrided nuclear fuel cladding. To this end, nanoindentation tests were performed on ZIRLO samples in as-received state, on a hydride blister and in samples with 150 and 1200 ppm of hydrogen homogeneously distributed along the hoop direction of the cladding. The results show that the measured mechanical properties of the zirconium hydrides and ZIRLO matrix (Young's modulus, hardness and yield stress) are rather similar. From the experimental data, the hydride volume fraction in the cladding samples with 150 and 1200 ppm was estimated and the average mechanical properties were calculated by means of the rule of mixtures. These values were compared with those obtained from ring compression tests. Good agreement between the results obtained by both methods was found.

  11. Development of hydride absorber for fast reactor. Application of hafnium hydride to control rod of large fast reactor

    International Nuclear Information System (INIS)

    The application of hafnium hydride (Hf-hydride) to a control rod for a large fast reactor where the B4C control rod is originally employed is studied. Three types of Hf-hydride control rods are designed. The control rod worth and its change during the burnup are evaluated for different hydrogen-to-hafnium ratios and are compared with those of the original B4C control rod. The result indicates that the worths of the Hf-hydride and the 10B-enriched B4C control rods are approximately the same, and the lifetime of the Hf-hydride control rod is almost four times longer than that of the 10B-enriched B4C control rod. The core performances of the shutdown margin, sodium void reactivity, Doppler reactivity coefficient, and breeding ratio are analyzed. It is indicated that those for the Hf-hydride control rod are almost the same as those for the original B4C control rod. The behavior of neutrons moderated by the Hf-hydride control rod is analyzed. It is confirmed that the Hf-hydride control rod does not cause any thermal spike problems in the fast reactor core. (author)

  12. Arsenic (As Contamination in Different Food and Dietary Samples from Several Districts of Bangladesh and Arsenic (As Detection, Mitigation and Toxicity Measurement and impact of Dietary Arsenic Exposure on Human Health

    Directory of Open Access Journals (Sweden)

    M A Awal

    2010-10-01

    Full Text Available Objective: To determine the level of arsenic concentration in vegetables and other food categories in three selected areas of Pabna district and to estimate quantitatively the dietary arsenic exposure in one of the arsenic contaminated areas of Bangladesh.Materials and Methods: The study was conducted in CharRuppur, Char mirkamari and Lakshmikunda village of IshwardiUpzila in Pabna district. Ishwardi (Town consists of 12 wardsand 37 mahallas. Arsenic was detected in the ADM Lab,Department of Pharmacology, Bangladesh Agricultural University, Mymensingh with Hydride Generation Atomic Absorption Spectrophotometer (HG-AAS; PG-990, PG Instruments Ltd. UK. Arsenic was detected by forming AsH3 at below pH 1.0 after the reaction of As with a solution of sodiumborohydride (NaBH4, sodium hydroxide (NaOH, M=40,000g/mol, and 10% HCl. In this test, standard was maintained asAsV ranging from 0 to 12.5 μg/L.Results: A total of 120 vegetable samples, 15 rice samples and15 fish samples were collected from five different markets ofthree different villages of Pabna district and were tested forarsenic concentration. Findings demonstrated that the mean concentration of As in leafy vegetables (0.52 μg g-1 was significantly higher compared to those found in fruity (0.422μg g-1 and root & tuber vegetables (0.486 μg g-1.Conclusion: Underground Contaminated water was the major source for the As contamination of various products in Pabna.The arsenic levels were found higher among the leafy vegetables samples in comparison to fruit and root & tuber vegetables. Further studies will be conducted to search the genetic risk factors of arsenic toxicity in the population of the mostly affected people.

  13. NATO Advanced Study Institute on Metal Hydrides

    CERN Document Server

    1981-01-01

    In the last five years, the study of metal hydrides has ex­ panded enormously due to the potential technological importance of this class of materials in hydrogen based energy conversion schemes. The scope of this activity has been worldwide among the industrially advanced nations. There has been a consensus among researchers in both fundamental and applied areas that a more basic understanding of the properties of metal/hydrogen syster;,s is required in order to provide a rational basis for the selection of materials for specific applications. The current worldwide need for and interest in research in metal hydrides indicated the timeliness of an Advanced Study Insti­ tute to provide an in-depth view of the field for those active in its various aspects. The inclusion of speakers from non-NATO coun­ tries provided the opportunity for cross-fertilization of ideas for future research. While the emphasis of the Institute was on basic properties, there was a conscious effort to stimulate interest in the applic...

  14. Urinary 8-hydroxydeoxyguanosine and urothelial carcinoma risk in low arsenic exposure area

    International Nuclear Information System (INIS)

    Arsenic is a well-documented human carcinogen and is known to cause oxidative stress in cultured cells and animals. A hospital-based case-control study was conducted to evaluate the relationship among the levels of urinary 8-hydroxydeoxyguanosine (8-OHdG), the arsenic profile, and urothelial carcinoma (UC). Urinary 8-OHdG was measured by using high-sensitivity enzyme-linked immunosorbent assay (ELISA) kits. The urinary species of inorganic arsenic and their metabolites were analyzed by high-performance liquid chromatography (HPLC) and hydride generator-atomic absorption spectrometry (HG-AAS). This study showed that the mean urinary concentration of total arsenics was significantly higher, at 37.67 ± 2.98 μg/g creatinine, for UC patients than for healthy controls of 21.10 ± 0.79 μg/g creatinine (p < 0.01). Urinary 8-OHdG levels correlated with urinary total arsenic concentrations (r = 0.19, p < 0.01). There were significantly higher 8-OHdG levels, of 7.48 ± 0.97 ng/mg creatinine in UC patients, compared to healthy controls of 5.95 ± 0.21 ng/mg creatinine. Furthermore, female UC patients had higher 8-OHdG levels of 9.22 ± 0.75 than those of males at 5.76 ± 0.25 ng/mg creatinine (p < 0.01). Multiple linear regression analyses revealed that high urinary 8-OHdG levels were associated with increased total arsenic concentrations, inorganic arsenite, monomethylarsonic acid (MMA), and dimethylarsenate (DMA) as well as the primary methylation index (PMI) even after adjusting for age, gender, and UC status. The results suggest that oxidative DNA damage was associated with arsenic exposure, even at low urinary level of arsenic

  15. Arsenic methylation capacity and developmental delay in preschool children in Taiwan.

    Science.gov (United States)

    Hsieh, Ru-Lan; Huang, Ya-Li; Shiue, Horng-Sheng; Huang, Shiau-Rung; Lin, Ming-I; Mu, Shu-Chi; Chung, Chi-Jung; Hsueh, Yu-Mei

    2014-07-01

    Environmental exposure to lead or mercury can cause neurodevelopmental damage. Arsenic is another neurotoxicant that can affect intellectual function in children. This study was designed to explore the difference of arsenic methylation capacity indices between with and without developmental delay in preschool children. We also aimed to identify whether blood levels of lead or mercury modify the effect of arsenic methylation capacity indices. A cross sectional study was conducted from August 2010 to March 2012. All participants recruited from the Shin Kong Wu Ho-Su Memorial Teaching Hospital. In all, 63 children with developmental delay and 35 children without developmental delay were recruited. Urinary arsenic species, including arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)) were measured with a high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Lead and mercury levels of red blood cells were measured by inductively coupled mass spectrometry. All participants underwent developmental assessments to confirm developmental delays, including evaluations of gross motor, fine motor, speech-language, cognition, social, and emotional domains. Urinary total arsenic and MMA(V) percentage were significantly positively associated and DMA(V) percentage was negatively associated with the risk of developmental delay in a dose-dependent manner after adjustment for blood lead or mercury levels and other risk factors. A multivariate regression analysis indicated that blood lead level and arsenic methylation capacity each independently contributed to the risk of developmental delay. This is the first study to show that arsenic methylation capacity is associated with developmental delay, even without obvious environmental arsenic exposure.

  16. Low-level arsenic exposure: Nutritional and dietary predictors in first-grade Uruguayan children.

    Science.gov (United States)

    Kordas, Katarzyna; Queirolo, Elena I; Mañay, Nelly; Peregalli, Fabiana; Hsiao, Pao Ying; Lu, Ying; Vahter, Marie

    2016-05-01

    Arsenic exposure in children is a public health concern but is understudied in relation to the predictors, and effects of low-level exposure. We examined the extent and dietary predictors of exposure to inorganic arsenic in 5-8 year old children from Montevideo, Uruguay. Children were recruited at school; 357 were enrolled, 328 collected morning urine samples, and 317 had two 24-h dietary recalls. Urinary arsenic metabolites, i.e. inorganic arsenic (iAs), methylarsonic acid (MMA), and dimethylarsinic acid (DMA), were measured using high-performance liquid chromatography with hydride generation and inductively coupled plasma mass spectrometry (HPLC-HG-ICP-MS), and the sum concentration (U-As) used for exposure assessment. Proportions of arsenic metabolites (%iAs, %MMA and %DMA) in urine were modelled in OLS regressions as functions of food groups, dietary patterns, nutrient intake, and nutritional status. Exposure to arsenic was low (median U-As: 9.9µg/L) and household water (water As: median 0.45µg/L) was not a major contributor to exposure. Children with higher consumption of rice had higher U-As but lower %iAs, %MMA, and higher %DMA. Children with higher meat consumption had lower %iAs and higher %DMA. Higher scores on "nutrient dense" dietary pattern were related to lower %iAs and %MMA, and higher %DMA. Higher intake of dietary folate was associated with lower %MMA and higher %DMA. Overweight children had lower %MMA and higher %DMA than normal-weight children. In summary, rice was an important predictor of exposure to inorganic arsenic and DMA. Higher meat and folate consumption, diet rich in green leafy and red-orange vegetables and eggs, and higher BMI contributed to higher arsenic methylation capacity. PMID:26828624

  17. Isotope exchange between gaseous hydrogen and uranium hydride powder

    International Nuclear Information System (INIS)

    Highlights: • Isotope exchange between hydrogen gas and uranium hydride powder can be rapid and reversible. • Gas–solid exchange rate is controlled by transport within ∼0.7 μm hydride particles. • Gas chromatographic separation of hydrogen isotopes using uranium hydride is feasible. - Abstract: Isotope exchange between gaseous hydrogen and solid uranium hydride has been studied by flowing hydrogen (deuterium) gas through packed powder beds of uranium deuteride (hydride). We used a residual gas analyzer system to perform real-time analysis of the effluent gas composition. We also developed an exchange and transport model and, by fitting it to the experimental data, extracted kinetic parameters for the isotope exchange reaction. Our results suggest that, from approximately 70 to 700 kPa and 25 to 400 °C, the gas-to-solid exchange rate is controlled by hydrogen and deuterium transport within the ∼0.7 μm diameter uranium hydride particles. We use our kinetic parameters to show that gas chromatographic separation of hydrogen and deuterium using uranium hydride could be feasible

  18. USEPA Arsenic Demonstration Program

    Science.gov (United States)

    The presentation provides background information on the USEPA arsenic removal program. The summary includes information on the history of the program, sites and technology selected, and a summary of the data collected from two completed projects.

  19. Hydrogen storage in metal hydrides and complex hydrides; Wasserstoffspeicherung in Metall- und komplexen Hydriden - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bielmann, M.; Zuettel, A.

    2007-07-01

    This final report for the Swiss Federal Office of Energy (SFOE), reports on work done in 2007 at the Swiss Federal Laboratories for Materials Science and Technology EMPA on the storage of hydrogen in metal hydrides and complex hydrides. In particular, the use of tetrahydroborates is noted. The potential of this class of materials is stressed. The structures at room-temperature were examined using neutron and X-ray diffraction methods. Thermodynamic methods helped determine the thermodynamic stability of the materials. Also, a complete energy diagram for the materials was developed. The use of silicon oxide to reduce activation energy and its catalytic effects are discussed. The challenges placed by desorption mechanisms are noted. The authors note that reversibility is basically proven.

  20. EXAFS study on arsenic species and transformation in arsenic hyperaccumulator

    Institute of Scientific and Technical Information of China (English)

    HUANG; Zechun; CHEN; Tongbin; LEI; Mei; HU; Tiandou; HUANG

    2004-01-01

    Synchrotron radiation extended X-ray absorption fine structure (SR EXAFS) was employed to study the transformation of coordination environment and the redox speciation of arsenic in a newly discovered arsenic hyperaccumulator, Cretan brake (Pteris cretica L. var nervosa Thunb). It showed that the arsenic in the plant mainly coordinated with oxygen, except that some arsenic coordinated with S as As-GSH in root. The complexation of arsenic with GSH might not be the predominant detoxification mechanism in Cretan brake. Although some arsenic in root presented as As(V) in Na2HAsO4 treatments, most of arsenic in plant presented as As(III)-O in both treatments, indicating that As(V) tended to be reduced to As(III) after it was taken up into the root, and arsenic was kept as As(III) when it was transported to the above-ground tissues. The reduction of As(V) primarily proceeded in the root.

  1. PIE techniques for hydride reorientation test at NDC

    International Nuclear Information System (INIS)

    Dry storage of spent fuels in the interim storage facility is being planned in Japan. However, the gradual deterioration of the mechanical property of fuel cladding due to internal pressure and temperature during the storage term is known. Therefore, the integrity of stored fuel rods should be confirmed before the start of dry storage. For the last several years, NDC had a lot of experiences on the hydride reorientation test. The specimen preparation techniques on the hydride reorientation test and the mechanical testing techniques after the hydride reorientation are shown in this paper. (author)

  2. Lead, cadmium, arsenic and mercury in canned tuna fish marketed in Tehran, Iran.

    Science.gov (United States)

    Andayesh, Shirin; Hadiani, Mohammad Rasoul; Mousavi, Zahra; Shoeibi, Shahram

    2015-01-01

    Fifty-four canned tuna fish samples corresponding to 10 widely used different brands were purchased from local markets in Tehran, Iran during 2012-2013 and analysed on heavy metals. Mercury was determined by a direct mercury analyser without any sample preparation. For analysis of other elements samples were digested using a microwave apparatus. Lead and cadmium were determined by graphite furnace atomic absorption spectrometry and arsenic via hydride vapour generation. All samples had arsenic and mercury contamination. Arsenic levels showed a range of 0.25-1.42 mg kg(-1), which might be due to lack of national and international limits for arsenic in canned tuna fish. Lead and cadmium were measured in a small number of samples with a mean of 0.053 ± 0.058 mg kg(-1) and 0.013 ± 0.015 mg kg(-1), respectively. Results obtained for these heavy metals in all samples were lower than the corresponding limits, whereas arsenic and mercury contents might raise some attention.

  3. Analytical speciation as a tool to assess arsenic behaviour in soils polluted by mining.

    Science.gov (United States)

    Ruiz-Chancho, M J; López-Sánchez, J F; Rubio, R

    2007-01-01

    A study is performed to evaluate the occurrence of arsenic in polluted soils using acidic extractions and liquid chromatography-hydride generation-atomic fluorescence spectrometry (LC-HG-AFS) for speciation analysis. Seven soil samples were collected in an abandoned area polluted by mining in the Eastern Pyrenees (Spain), and two uncontaminated soils were taken for reference purposes. Moreover, the total arsenic content is evaluated in two different sieved fractions in order to obtain information on the possible particle-size-dependent association of arsenic with soil components. Soil samples were extracted with both phosphoric and ascorbic acids and the stabilities of the extracted species were studied. The arsenic species were determined by LC-HG-AFS. In addition, the ability of soil grinding to effect species change is also assessed. Arsenite and arsenate were found in the polluted soils, but only arsenate was found in the unpolluted soils. The quality of the results was assessed through a mass balance calculation and by analysing two soil Certified Reference Materials. Valuable information regarding arsenic occurrence in the studied soils is obtained from the speciation results. The presence of arsenite in the extracts can be attributed to arsenopyrite residues, whereas the presence of arsenate indicates release from weathered material. PMID:17171341

  4. Determination of As(III) and As(V) species in some natural water and food samples by solid-phase extraction on Streptococcus pyogenes immobilized on Sepabeads SP 70 and hydride generation atomic absorption spectrometry.

    Science.gov (United States)

    Uluozlu, Ozgur Dogan; Tuzen, Mustafa; Mendil, Durali; Soylak, Mustafa

    2010-05-01

    The speciation of arsenic(III) and arsenic(V) by using Streptococcus pyogenes immobilized on Sepabeads SP 70 resin has been investigated with solid-phase extraction method. The arsenic levels were determined hydride generation atomic absorption spectrometry (HGAAS) in sample solutions. The procedure presented based on quantitative recoveries of As(III) as >95%. Also the As(V) recoveries were obtained as method. After reduction of As(V) by using KI and ascorbic acid and waiting 1h later, the system was applied to determination of total arsenic. As(V) was found as the difference between the total As and As(III) content. Various experimental parameters such as pH, amount of microorganism, sample volume, etc. were investigated. The capacity of biosorbent for arsenic(III) was calculated as 7.3 mg/g. The preconcentration factor was found as 36. The relative standard deviation was calculated below 8%. Limit of detection was calculated as 13 ng/L. The validation of the presented procedure was tested by analysis of standard reference materials (NIST SRM 1568a Rice floor and GBW 07605 Tea) and obtained fairly compatible results. The procedure was also successfully applied to arsenic speciation and determination of some natural water and food samples.

  5. Hydrogen storage in sodium aluminum hydride.

    Energy Technology Data Exchange (ETDEWEB)

    Ozolins, Vidvuds; Herberg, J.L. (Lawrence Livermore National Laboratories, Livermore, CA); McCarty, Kevin F.; Maxwell, Robert S. (Lawrence Livermore National Laboratories, Livermore, CA); Stumpf, Roland Rudolph; Majzoub, Eric H.

    2005-11-01

    Sodium aluminum hydride, NaAlH{sub 4}, has been studied for use as a hydrogen storage material. The effect of Ti, as a few mol. % dopant in the system to increase kinetics of hydrogen sorption, is studied with respect to changes in lattice structure of the crystal. No Ti substitution is found in the crystal lattice. Electronic structure calculations indicate that the NaAlH{sub 4} and Na{sub 3}AlH{sub 6} structures are complex-ionic hydrides with Na{sup +} cations and AlH{sub 4}{sup -} and AlH{sub 6}{sup 3-} anions, respectively. Compound formation studies indicate the primary Ti-compound formed when doping the material at 33 at. % is TiAl{sub 3} , and likely Ti-Al compounds at lower doping rates. A general study of sorption kinetics of NaAlH{sub 4}, when doped with a variety of Ti-halide compounds, indicates a uniform response with the kinetics similar for all dopants. NMR multiple quantum studies of solution-doped samples indicate solvent interaction with the doped alanate. Raman spectroscopy was used to study the lattice dynamics of NaAlH{sub 4}, and illustrated the molecular ionic nature of the lattice as a separation of vibrational modes between the AlH{sub 4}{sup -} anion-modes and lattice-modes. In-situ Raman measurements indicate a stable AlH{sub 4}{sup -} anion that is stable at the melting temperature of NaAlH{sub 4}, indicating that Ti-dopants must affect the Al-H bond strength.

  6. The progress of nanocrystalline hydride electrode materials

    International Nuclear Information System (INIS)

    This paper reviews research at the Institute of Materials Science and Engineering, Poznan University of Technology, on the synthesis of nanocrystalline hydride electrode materials. Nanocrystalline materials have been synthesized by mechanical alloying (MA) followed by annealing. Examples of the materials include TiFe-, ZrV2-, LaNi5 and Mg2Ni-type phases. Details on the process used and the enhancement of properties due to the nanoscale structures are presented. The synthesized alloys were used as negative electrode materials for Ni-MH battery. The properties of hydrogen host materials can be modified substantially by alloying to obtain the desired storage characteristics. For example, it was found that the respective replacement of Fe in TiFe by Ni and/or by Cr, Co, Mo improved not only the discharge capacity but also the cycle life of these electrodes. The hydrogen storage properties of nanocrystalline ZrV2- and LaNi5-type powders prepared by mechanical alloying and annealing show no big difference with those of melt casting (polycrystalline) alloys. On the other hand, a partial substitution of Mg by Mn or Al in Mg2Ni alloy leads to an increase in discharge capacity, at room temperature. Furthermore, the effect of the nickel and graphite coating on the structure of some nanocrystalline alloys and the electrodes characteristics were investigated. In the case of Mg2Ni-type alloy mechanical coating with graphite effectively reduced the degradation rate of the studied electrode materials. The combination of a nanocrystalline TiFe-, ZrV2- and LaNi5-type hydride electrodes and a nickel positive electrode to form a Ni-MH battery, has been successful. (authors)

  7. Acute and chronic arsenic toxicity

    OpenAIRE

    Ratnaike, R.

    2003-01-01

    Arsenic toxicity is a global health problem affecting many millions of people. Contamination is caused by arsenic from natural geological sources leaching into aquifers, contaminating drinking water and may also occur from mining and other industrial processes. Arsenic is present as a contaminant in many traditional remedies. Arsenic trioxide is now used to treat acute promyelocytic leukaemia. Absorption occurs predominantly from ingestion from the small intestine, though minimal absorption o...

  8. Artificial exomuscle investigations for applications-metal hydride

    International Nuclear Information System (INIS)

    In pursuing the development of bionic devices, Victhom identified a need for technologies that could replace current motorized systems and be better integrated into the human body motion. The actuators used to obtain large displacements are noisy, heavy, and do not adequately reproduce human muscle behavior. Subsequently, a project at Victhom was devoted to the development of active materials to obtain an artificial exomuscle actuator. An exhaustive literature review was done at Victhom to identify promising active materials for the development of artificial muscles. According to this review, metal hydrides were identified as a promising technology for artificial muscle development. Victhom's investigations focused on determining metal hydride actuator potential in the context of bionics technology. Based on metal hydride properties and artificial muscle requirements such as force, displacement and rise time, an exomuscle was built. In addition, a finite element model, including heat and mass transfer in the metal hydride, was developed and implemented in FEMLAB software. (review article)

  9. Out-of-pile accelerated hydriding of Zircaloy fasteners

    International Nuclear Information System (INIS)

    Mechanical joints between Zircaloy and nickel-bearing alloys, mainly the Zircaloy-4/Inconel-600 combination, were exposed to water at 4500F and 5200F to study hydriding of Zircaloy in contact with a dissimilar metal. Accelerated hydriding of the Zircaloy occurred at both temperatures. At 4500F the dissolved hydrogen level of the water was over ten times that at 5200F. At 5200F the initially high hydrogen ingress rate decreased rapidly as exposure time increased and was effectively shut off in about 25 days. Severely hydrided Zircaloy components successfully withstood thermal cycling and mechanical testing. Chromium plating of the nickel-bearing parts was found to be an effective and practical barrier in preventing nickel-alloy smearing and accelerated hydriding of Zircaloy

  10. Artificial exomuscle investigations for applications-metal hydride

    Energy Technology Data Exchange (ETDEWEB)

    Crevier, Marie-Charlotte; Richard, Martin; Rittenhouse, D Matheson; Roy, Pierre-Olivier; Bedard, Stephane [Victhom Human Bionics Inc., Saint-Augustin-de-Desmaures, QC (Canada)

    2007-03-01

    In pursuing the development of bionic devices, Victhom identified a need for technologies that could replace current motorized systems and be better integrated into the human body motion. The actuators used to obtain large displacements are noisy, heavy, and do not adequately reproduce human muscle behavior. Subsequently, a project at Victhom was devoted to the development of active materials to obtain an artificial exomuscle actuator. An exhaustive literature review was done at Victhom to identify promising active materials for the development of artificial muscles. According to this review, metal hydrides were identified as a promising technology for artificial muscle development. Victhom's investigations focused on determining metal hydride actuator potential in the context of bionics technology. Based on metal hydride properties and artificial muscle requirements such as force, displacement and rise time, an exomuscle was built. In addition, a finite element model, including heat and mass transfer in the metal hydride, was developed and implemented in FEMLAB software. (review article)

  11. Urinary arsenic methylation capability and carotid atherosclerosis risk in subjects living in arsenicosis-hyperendemic areas in southwestern Taiwan

    International Nuclear Information System (INIS)

    Long-term exposure to inorganic arsenic from artesian drinking well water is associated with carotid atherosclerosis in the Blackfoot Disease (BFD)-hyperendemic area in Taiwan. The current study examined the arsenic methylation capacity and its risk on carotid atherosclerosis. A total of 304 adults (158 men and 146 women) residing in the BFD-hyperendemic area were included. The extent of carotid atherosclerosis was assessed by duplex ultrasonography. Chronic arsenic exposure was estimated by an index of cumulative arsenic exposure (CAE) and the duration of artesian well water consumption. Urinary levels of inorganic arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid [MMA(V)] and dimethylarsinic acid [DMA(V)] were determined by high performance liquid chromatography linked on-line to a hydride generator and atomic absorption spectrometry (HPLC-HG-AAS). The percentage of arsenic species, primary methylation index [PMI = MMA(V) / (As(III) + As(V)] and secondary methylation index [SMI = DMA(V) / MMA(V)] were calculated and employed as indicators of arsenic methylation capacity. Results showed that women and younger subjects had a more efficient arsenic methylation capacity than did men and the elderly. Carotid atherosclerosis cases had a significantly greater percentage of MMA(V) [%MMA(V)] and a lower percentage of DMA [%DMA (V)] compared to controls. Subjects in the highest two tertiles of PMI with a median of CAE > 0 mg/L-year had an odds ratio (OR) and a 95% confidence interval (CI) of carotid atherosclerosis of 2.61 and 0.98-6.90 compared to those in the highest two tertiles of PMI with a CAE = 0 mg/L-year. We conclude that individuals with greater exposure to arsenic and lower capacity to methylate inorganic arsenic may be at a higher risk to carotid atherosclerosis

  12. Electronic structure and optical properties of lightweight metal hydrides

    NARCIS (Netherlands)

    Setten, van M.J.; Popa, V.A.; Wijs, de G.A.; Brocks, G.

    2007-01-01

    We study the dielectric functions of the series of simple hydrides LiH, NaH, MgH2, and AlH3, and of the complex hydrides Li3AlH6, Na3AlH6, LiAlH4, NaAlH4, and Mg(AlH4)2, using first-principles density-functional theory and GW calculations. All compounds are large gap insulators with GW single-partic

  13. Electronic structure of ternary hydrides based on light elements

    Energy Technology Data Exchange (ETDEWEB)

    Orgaz, E. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico)]. E-mail: orgaz@eros.pquim.unam.mx; Membrillo, A. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico); Castaneda, R. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico); Aburto, A. [Departamento de Fisica, Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico)

    2005-12-08

    Ternary hydrides based on light elements are interesting owing to the high available energy density. In this work we focused into the electronic structure of a series of known systems having the general formula AMH{sub 4}(A=Li,Na,M=B,Al). We computed the energy bands and the total and partial density of states using the linear-augmented plane waves method. In this report, we discuss the chemical bonding in this series of complex hydrides.

  14. Thin-film metal hydrides for solar energy applications

    OpenAIRE

    2012-01-01

    Thin-film metal hydrides may become important solar energy materials in the future. This thesis demonstrates interesting material properties of metal hydride films, relevant for applications as semiconducting materials for photovoltaic (PV) solar cells and for regulation of light using smart window technology. List of papers. Papers II-VI are removed from the thesis due to copyright restrictions. Paper I C. Platzer-Björkman, T. Mongstad, S. Zh. Karazhanov, J. P. Mæhlen, E. S. Marst...

  15. Method of selective reduction of polyhalosilanes with alkyltin hydrides

    Science.gov (United States)

    Sharp, Kenneth G.; D'Errico, John J.

    1989-01-01

    The invention relates to the selective and stepwise reduction of polyhalosilanes by reacting at room temperature or below with alkyltin hydrides without the use of free radical intermediates. Alkyltin hydrides selectively and stepwise reduce the Si--Br, Si--Cl, or Si--I bonds while leaving intact any Si--F bonds. When two or more different halogens are present on the polyhalosilane, the halogen with the highest atomic weight is preferentially reduced.

  16. Method of selective reduction of halodisilanes with alkyltin hydrides

    Science.gov (United States)

    D'Errico, John J.; Sharp, Kenneth G.

    1989-01-01

    The invention relates to the selective and sequential reduction of halodisilanes by reacting these compounds at room temperature or below with trialkyltin hydrides or dialkyltin dihydrides without the use of free radical intermediates. The alkyltin hydrides selectively and sequentially reduce the Si-Cl, Si-Br or Si-I bonds while leaving intact the Si-Si and Si-F bonds present.

  17. Arsenic (+3 oxidation state) methyltransferase and the methylation of arsenicals in the invertebrate chordate Ciona intestinalis

    Science.gov (United States)

    Biotransformation of inorganic arsenic (iAs) involves methylation catalyzed by arsenic (+3 oxidation state) methyltransferase (As3mt), yielding mono- , di- , and trimethylated arsenicals. To investigate the evolution of molecular mechanisms that mediate arsenic biotransformation,...

  18. Probabilistic Risk Assessment of Cancer from Exposure Inorganic Arsenic in Duplicate Food by Villagers in Ronphibun, Thailand

    Directory of Open Access Journals (Sweden)

    Piyawat Saipan

    2010-07-01

    Full Text Available Ronphibun district is a district in Nakorn Si Thammarat province, within southern Thailand. This district is the site of several former tin mines that were in operation 100 years ago. Arsenic contamination caused by past mining activities remains in the area. The specific purpose of this study was conducted to assess cancer risk in people living within Ronphibun district from exposure to inorganic arsenic via duplicate food using probabilistic risk assessment. A hundred and fifty duplicate food samples were collected from participants. Inorganic arsenic concentrations are determined by hydride generation atomic absorption spectrometry. Inorganic arsenic concentrations in duplicate food ranged from 0.16 to 0.42 μg/g dry weight. The probabilistic carcinogenic risk levels were 6.76 x 10-4 and 1.74 x 10-3 based on the 50th and 95th percentile, respectively. Risk values for people in Ronphibun from exposure to inorganic arsenic remained higher than the acceptable target risk. Sensitivity analysis indicted that exposure duration and concentrations of arsenic in food were the two most influential of cancer risk estimates.

  19. Novel fuel cell stack with coupled metal hydride containers

    Science.gov (United States)

    Liu, Zhixiang; Li, Yan; Bu, Qingyuan; Guzy, Christopher J.; Li, Qi; Chen, Weirong; Wang, Cheng

    2016-10-01

    Air-cooled, self-humidifying hydrogen fuel cells are often used for backup and portable power sources, with a metal hydride used as the hydrogen storage material. To provide a stable hydrogen flow to the fuel cell stack, heat must be provided to the metal hydride. Conventionally, the heat released from the exothermic reaction of hydrogen and oxygen in the fuel cell stack to the exhaust air is used to heat a separate metal hydride container. In this case, the heat is only partially used instead of being more closely coupled because of the heat transfer resistances in the system. To achieve better heat integration, a novel scheme is proposed whereby hydrogen storage and single fuel cells are more closely coupled. Based on this idea, metal hydride containers in the form of cooling plates were assembled between each pair of cells in the stack so that the heat could be directly transferred to a metal hydride container of much larger surface-to-volume ratio than conventional separate containers. A heat coupled fuel cell portable power source with 10 cells and 11 metal hydride containers was constructed and the experimental results show that this scheme is beneficial for the heat management of fuel cell stack.

  20. Optimization of Hydride Rim Formation in Unirradiated Zr 4 Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Shimskey, Rick W.; Hanson, Brady D.; MacFarlan, Paul J.

    2013-09-30

    The purpose of this work is to build on the results reported in the M2 milestone M2FT 13PN0805051, document number FCRD-USED-2013-000151 (Hanson, 2013). In that work, it was demonstrated that unirradiated samples of zircaloy-4 cladding could be pre-hydrided at temperatures below 400°C in pure hydrogen gas and that the growth of hydrides on the surface could be controlled by changing the surface condition of the samples and form a desired hydride rim on the outside diameter of the cladding. The work performed at Pacific Northwest National Laboratory since the issuing of the M2 milestone has focused its efforts to optimize the formation of a hydride rim on available zircaloy-4 cladding samples by controlling temperature variation and gas flow control during pre-hydriding treatments. Surface conditioning of the outside surface was also examined as a variable. The results of test indicate that much of the variability in the hydride thickness is due to temperature variation occurring in the furnaces as well as how hydrogen gas flows across the sample surface. Efforts to examine other alloys, gas concentrations, and different surface conditioning plan to be pursed in the next FY as more cladding samples become available

  1. Effect of niobium additions on initial hydriding kinetics of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ruiwen, E-mail: ruiwenli@163.com; Wang, Xiaolin

    2014-06-01

    To study the behavior of hydrogen corrosion at the surface of U, U–2.5 wt%Nb alloy and U–5.7 wt%Nb, a gas–solid reaction system with an in situ microscope was designed. The nucleation and growth of the hydride of the alloy were continuously observed and recorded by a computer. The different characteristics of the hydrides on U metal and U–2.5 wt%Nb showed that the later alloy is more susceptible to hydrogen corrosion than the former. The growth rate of hydride of U–2.5 wt%Nb, calculated by measuring the perimeter of the hydride spots recorded by the in situ microscope, exhibited a reaction temperature dependency in the range of 40–160 °C, for pressure of 0.8 × 10{sup 5} Pa. An Arrhenius plot for growth rate versus temperature yielded activation energy of 24.34 kJ/mol for the hydriding of U–2.5 wt%Nb alloy. The maximum hydriding rate was obtained at 125 °C, whose thermodynamics reason was discussed.

  2. Polymorphisms in cell cycle regulatory genes, urinary arsenic profile and urothelial carcinoma

    International Nuclear Information System (INIS)

    Introduction: Polymorphisms in p53, p21 and CCND1 could regulate the progression of the cell cycle and might increase the susceptibility to inorganic arsenic-related cancer risk. The goal of our study was to evaluate the roles of cell cycle regulatory gene polymorphisms in the carcinogenesis of arsenic-related urothelial carcinoma (UC). Methods: A hospital-based case-controlled study was conducted to explore the relationships among the urinary arsenic profile, 8-hydroxydeoxyguanosine (8-OHdG) levels, p53 codon 72, p21 codon 31 and CCND1 G870A polymorphisms and UC risk. The urinary arsenic profile was determined using high-performance liquid chromatography (HPLC) and hydride generator-atomic absorption spectrometry (HG-AAS). 8-OHdG levels were measured by high-sensitivity enzyme-linked immunosorbent assay (ELISA) kits. Genotyping was conducted using polymerase chain reaction-restriction fragment length polymerase (PCR-RFLP). Results: Subjects carrying the p21 Arg/Arg genotype had an increased UC risk (age and gender adjusted OR = 1.53; 95% CI, 1.02-2.29). However, there was no association of p53 or CCND1 polymorphisms with UC risk. Significant effects were observed in terms of a combination of the three gene polymorphisms and a cumulative exposure of cigarette smoking, along with the urinary arsenic profile on the UC risk. The higher total arsenic concentration, monomethylarsonic acid percentage (MMA%) and lower dimethylarsinic acid percentage (DMA%), possessed greater gene variant numbers, had a higher UC risk and revealed significant dose-response relationships. However, effects of urinary 8-OHdG levels combined with three gene polymorphisms did not seem to be important for UC risk. Conclusions: The results showed that the variant genotype of p21 might be a predictor of inorganic arsenic-related UC risk

  3. Total and Inorganic Arsenic Contents in Some Edible Zingiberaceous Rhizomes in Thailand

    Directory of Open Access Journals (Sweden)

    Chomkamon Ubonnuch

    2013-01-01

    Full Text Available The arsenic accumulation in rhizomes of Zingiberaceous plants was determined by atomic absorption spectrometry interfaced with hydride generation system (HG-AAS. The raw herbal materials, rhizomes, were collected from different regions of Thailand between December 2011 and January 2012. Six well-known Zingiberaceous plants, 16 samples from each and a total of 96 samples, were analyzed Alpinia galanga (Khaa, Boesenbergia rotunda (Kra-chaai, Curcuma longa (Khamin-chan, Curcuma zedoaria (Khamin-oi, Zingiber cassumunar (Plai and Zingiber officinale (Ginger. Concentrations of total arsenic based on dry weight were 92.4±9.2, 103.5±20.8, 61.7±12.5, 89.8±17.5, 106.7±19.5 and 69.3±11.8 ng/g, respectively and inorganic arsenic were 48.8±7.0, 66.3±12.7, 25.5±5.0, 38.7±4.7, 71.2±11.6, and 38.5±5.5 ng/g, respectively. Among these, Plai and Kra-chaai exhibited the highest levels of total arsenic and inorganic arsenic accumulation that remind consumers to be aware of excess consuming of these rhizomes. On the contrary, the lowest value found in Khamin-chan indicating natural dietary supplements and herbal medicines comprising Kamin-chan are safe from arsenic poison. All investigated amounts of total and inorganic arsenic were much lower than limits recommended by Thai Food and Drug Administration.

  4. Levels of toxic arsenic species in native terrestrial plants from soils polluted by former mining activities.

    Science.gov (United States)

    García-Salgado, Sara; Quijano, M Ángeles

    2014-03-01

    Ten native terrestrial plants from soils polluted by former mining activities (Mónica mine, NW Madrid, Spain), with high total arsenic concentration levels (up to 3500 μg g(-1)), have been studied to determine the fraction of arsenic present as toxic forms (inorganic and methylated species), which present a higher mobility and therefore the potential risk associated with their reintegration into the environment is high. Roots and aboveground parts were analyzed separately to assess possible transformations from translocation processes. Extractions were carried out with deionized water by microwave-assisted extraction at a temperature of 90 °C and three extraction steps of 7.5 min each. Total extracted arsenic concentrations were determined by inductively coupled plasma atomic emission spectrometry, showing extraction percentages from 9 to 39% (calculated as the ratio between total extracted arsenic (Asext) and total arsenic (AsT) concentrations in plants). Speciation studies, performed by high performance liquid chromatography-photo-oxidation-hydride generation-atomic fluorescence spectrometry, showed the main presence of arsenate (As(v)) (up to 350 μg g(-1)), followed by arsenite (As(iii)), in both plant parts. Monomethylarsonic acid (MMA) and trimethylarsine oxide (TMAO) were also found only in some plants. On the other hand, the use of 0.5 mol L(-1) acetic acid as an extractant led to higher extraction percentages (33-87%), but lower column recoveries, probably due to the extraction of arsenic compounds different to the toxic free ions studied, which may come from biotransformation mechanisms carried out by plants to reduce arsenic toxicity. However, As(v) concentrations increased up to 800 μg g(-1) in acid medium, indicating the probable release of As(v) from organoarsenic compounds and therefore a higher potential risk for the environment.

  5. Arsenic, Anaerobes, and Astrobiology

    Science.gov (United States)

    Stolz, J. F.; Oremland, R. S.; Switzer Blum, J.; Hoeft, S. E.; Baesman, S. M.; Bennett, S.; Miller, L. G.; Kulp, T. R.; Saltikov, C.

    2013-12-01

    Arsenic is an element best known for its highly poisonous nature, so it is not something one would associate with being a well-spring for life. Yet discoveries made over the past two decades have delineated that not only are some microbes resistant to arsenic, but that this element's primary redox states can be exploited to conserve energy and support prokaryotic growth ('arsenotrophy') in the absence of oxygen. Hence, arsenite [As(III)] can serve as an electron donor for chemo- or photo-autotrophy while arsenate [As(V)] will serve as an electron acceptor for chemo-heterotrophs and chemo-autotrophs. The phylogenetic diversity of these microbes is broad, encompassing many individual species from diverse taxonomic groups in the Domain Bacteria, with fewer representatives in the Domain Archaea. Speculation with regard to the evolutionary origins of the key functional genes in anaerobic arsenic transformations (arrA and arxA) and aerobic oxidation (aioB) has led to a disputation as to which gene and function is the most ancient and whether arsenic metabolism extended back into the Archaean. Regardless of its origin, robust arsenic metabolism has been documented in extreme environments that are rich in their arsenic content, such as hot springs and especially hypersaline soda lakes associated with volcanic regions. Searles Lake, CA is an extreme, salt-saturated end member where vigorous arsenic metabolism occurs, but there is no detectable sulfate-reduction or methanogenesis. The latter processes are too weak bio-energetically to survive as compared with arsenotrophy, and are also highly sensitive to the abundance of borate ions present in these locales. These observations have implications with respect to the search for microbial life elsewhere in the Solar System where volcanic-like processes have been operative. Hence, because of the likelihood of encountering dense brines in the regolith of Mars (formed by evapo-concentration) or beneath the ice layers of Europa

  6. Arsenic hyperaccumulator Pteris Vittata L. and its arsenic accumulation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An arsenic hyperaccumulator Pteris vittata L. (Chinese brake) was first discovered in China by means of field survey and greenhouse cultivation. Field survey showed that Chinese brake had large accumulating capacity to arsenic; the orders of arsenic content in different parts of the fern were as follows: leaves>leafstalks>roots, which is totally different from that of ordinary plants; bioaccumulation coefficients of the above ground parts of the fern decreased as a power function of soil arsenic contents. In the control of pot trials with normal unpolluted soil containing 9 mg/kg of arsenic, the bioaccumulation coefficients of the above ground parts and rhizoids of Chinese brake were as high as 71 and 80 respectively. Greenhouse cultivation in the contaminated soil from mining areas has shown that more than 1 times greater arsenic can be accumulated in the leaves of the fern than that of field samples with the largest content of 5070 mg/kg As on a dry matter basis. During greenhouse cultivation, arsenic content in the leaves of the fern increased linearly with time prolonging. Not only has Chinese brake extraordinary tolerance and accumulation to arsenic, but it grew rapidly with great biomass, wide distribution and easy adaptation to different environmental conditions as well. Therefore, it has great potential in future remediation of arsenic contamination. It also demonstrates important value for studies of arsenic physiology and biochemistry such as arsenic absorption, translocation and detoxification mechanisms in plants.

  7. Determination of arsenic, selenium and antimony by neutron activation analysis. Application to hair samples

    International Nuclear Information System (INIS)

    A fast rabbit system for instrumental activation analysis with reactor neutrons is described. Its use in the determination of selenium in hair is discussed. A survey is given of the correction factors which are inherent to the use of short-lived radionuclides. An alternative to INAA is NAA based on the separation of arsenic, selenium and antimony by hydride evaporation and adsorption to active carbon. Data for some Standard Reference Materials are given. This work was done under research contract 2440/RI/RB with the IAEA

  8. [Arsenic - Poison or medicine?].

    Science.gov (United States)

    Kulik-Kupka, Karolina; Koszowska, Aneta; Brończyk-Puzoń, Anna; Nowak, Justyna; Gwizdek, Katarzyna; Zubelewicz-Szkodzińska, Barbara

    2016-01-01

    Arsenic (As) is commonly known as a poison. Only a few people know that As has also been widely used in medicine. In the past years As and its compounds were used as a medicine for the treatment of such diseases as diabetes, psoriasis, syphilis, skin ulcers and joint diseases. Nowadays As is also used especially in the treatment of patients with acute promyelocytic leukemia. The International Agency for Research on Cancer (IARC) has recognized arsenic as an element with carcinogenic effect evidenced by epidemiological studies, but as previously mentioned it is also used in the treatment of neoplastic diseases. This underlines the specificity of the arsenic effects. Arsenic occurs widely in the natural environment, for example, it is present in soil and water, which contributes to its migration to food products. Long exposure to this element may lead to liver damages and also to changes in myocardium. Bearing in mind that such serious health problems can occur, monitoring of the As presence in the environmental media plays a very important role. In addition, the occupational risk of As exposure in the workplace should be identified and checked. Also the standards for As presence in food should be established. This paper presents a review of the 2015 publications based on the Medical database like PubMed and Polish Medical Bibliography. It includes the most important information about arsenic in both forms, poison and medicine.

  9. Chronic arsenic poisoning.

    Science.gov (United States)

    Hall, Alan H

    2002-03-10

    Symptomatic arsenic poisoning is not often seen in occupational exposure settings. Attempted homicide and deliberate long-term poisoning have resulted in chronic toxicity. Skin pigmentation changes, palmar and plantar hyperkeratoses, gastrointestinal symptoms, anemia, and liver disease are common. Noncirrhotic portal hypertension with bleeding esophageal varices, splenomegaly, and hypersplenism may occur. A metallic taste, gastrointestinal disturbances, and Mee's lines may be seen. Bone marrow depression is common. 'Blackfoot disease' has been associated with arsenic-contaminated drinking water in Taiwan; Raynaud's phenomenon and acrocyanosis also may occur. Large numbers of persons in areas of India, Pakistan, and several other countries have been chronically poisoned from naturally occurring arsenic in ground water. Toxic delirium and encephalopathy can be present. CCA-treated wood (chromated copper arsenate) is not a health risk unless burned in fireplaces or woodstoves. Peripheral neuropathy may also occur. Workplace exposure or chronic ingestion of arsenic-contaminated water or arsenical medications is associated with development of skin, lung, and other cancers. Treatment may incklude the use of chelating agents such as dimercaprol (BAL), dimercaptosuccinic acid (DMSA), and dimercaptopanesulfonic acid (DMPS).

  10. Study on the application of cold vapor atomic absorption spectrometry and hydride generation atomic absorption spectrometry for the determination of Hg and As traces in sea water samples

    International Nuclear Information System (INIS)

    The trace amount of total mercury (Hg) and arsenic (As) in sea water samples were quantitatively determined by using the Atomic Absorption Spectrometry connected with the hydride generation technique (HG-AAS) for As, and with the cold vapour technique (CV-AAS) for Hg. The experiments were carried out at room temperature on a Hydride System Module (HS55) combined with an Atomic Absorption Spectrometer (VARIO 6, Analytik Jena AG). The effect of reductants concentration, and that of matrix on the absorption intensity of each analyzed element was studied in details. The sea water sample after fitrating through a membrane with 0.45(μm-hole size was pre-treated with an oxidant or an reductant to obtain the identical medium. The absorption intensity of each element was then measured on the VARIO-6 under the optimum parameters for spectrometer such as: maximum wavelength, current of hollow cathode lamp, and that for hydride system such as cell temperature, speed of peristaltic pump, pump time, reaction time and rewash time, ect. The analytical procedures were set-up and applied for the determination of these above mentioned elements in the synthesized sea water sample and in the real sea water samples with high precision and accuracy. (author)

  11. Inorganic arsenic toxicosis in cattle.

    Science.gov (United States)

    Riviere, J E; Boosinger, T R; Everson, R J

    1981-03-01

    In 4 occurrences of arsenic poisoning in cattle, the principal clinical sign was acute hemorrhagic diarrhea attributable to hemorrhagic gastroenteritis. Arsenic concentrations in the liver, kidney and rumen contents varied. In one occurrence, arsenic in the hair of affected survivors was assayed at 0.8-3.40 ppm, vs 0.09-0.10 ppm in randomly selected control samples of hair. Sudden death was the only clinical sign in another occurrence in which gastric contents contained arsenic at 671 ppm. In another occurrence, arsenic poisoning caused lesions similar to those of salmonellosis.

  12. Effects of soil arsenic pollution on arsenic content and distribution in soybean%土壤砷污染对大豆砷含量与分布的影响

    Institute of Scientific and Technical Information of China (English)

    杨兰芳; 何婷; 赵莉

    2011-01-01

    通过土壤加砷盆栽大豆实验,利用氢化物发生-分光光度法测定大豆和土壤的砷含量,以研究土壤砷污染对大豆砷含量及其分布的影响.结果表明,大豆根、茎和籽粒砷含量均与土壤加砷水平呈极显著的线性相关,并呈根>茎>籽粒的规律.大豆收获后,土壤砷含量与土壤加砷水平呈极显著的线性相关,土壤砷的残留率在82%以上,与土壤加砷水平呈极显著的对数相关.大豆根、茎和籽粒的富砷量均与土壤加砷呈极显著的二次函数相关关系,大豆茎的富砷量是根富砷量的3.4~8.1倍,是籽粒富砷量的2.8~4.6倍.大豆吸收的砷有82%以上存在于地上部分,但大豆对土壤加砷的利用率只在万分之几.大豆富砷量和大豆对土壤砷的利用率均以茎最高,而富集系数则为根>茎>籽粒.总之,大豆砷含量受土壤砷水平决定,籽粒含砷量最低有利于砷污染土壤的利用,土壤砷污染具有长效性.%A soil pot experiment was conducted to investigate the effects of soil arsenic pollution on arsenic content and distribution in soybean and arsenic contents in soybean and soil were determined by the method of hydride generation spectrophotometry. The results showed that arsenic content in soybean roots, stalks and grains were significant linearly correlative to soil arsenic additions and took on an order of roots> stalks> grains. The arsenic contents in soybean-harvested soils were significant linearly correlative to soil arsenic additions,but the residual rates of arsenic in soil were more than 82% and significant exponentially correlative to soil arsenic additions. There was a significant quadratic function relationship between the arsenic accumulations in soybean roots, stalks and grains and soil arsenic additions, but the soybean arsenic accumulations in stalks were 3. 4-8.1 times as high as those in roots and 2. 8-4. 6 times as high as those in grains. Arsenic accumulations in

  13. Arsenic poisoning in cattle

    Energy Technology Data Exchange (ETDEWEB)

    McLennan, M.W.; Dodson, M.E.

    1972-06-01

    A case of acute arsenic poisoning in cattle was reported. The losses occurred on a property in the south east of South Australia. The weather had been hot for two or three days before the death occurred. The tank supplying the water trough had almost run dry. The cattle then attempted to meet their water requirements by drinking from the sheep dipping vat. A sample of rumen contents and a sample of water from the dipping vat were checked for arsenic. The rumen sample contained 45 ppM As/sub 2/O/sub 3/ and the sample of dipping fluid contained 200 ppM As. The lesions observed were similar to earlier reported arsenic poisoning. 5 references.

  14. Environmental Source of Arsenic Exposure

    Science.gov (United States)

    Chung, Jin-Yong; Yu, Seung-Do; Hong, Young-Seoub

    2014-01-01

    Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a recent World Health Organization report, arsenic from contaminated water can be quickly and easily absorbed and depending on its metabolic form, may adversely affect human health. Recently, the US Food and Drug Administration regulations for metals found in cosmetics to protect consumers against contaminations deemed deleterious to health; some cosmetics were found to contain a variety of chemicals including heavy metals, which are sometimes used as preservatives. Moreover, developing countries tend to have a growing number of industrial factories that unfortunately, harm the environment, especially in cities where industrial and vehicle emissions, as well as household activities, cause serious air pollution. Air is also an important source of arsenic exposure in areas with industrial activity. The presence of arsenic in airborne particulate matter is considered a risk for certain diseases. Taken together, various potential pathways of arsenic exposure seem to affect humans adversely, and future efforts to reduce arsenic exposure caused by environmental factors should be made. PMID:25284196

  15. Environmental source of arsenic exposure.

    Science.gov (United States)

    Chung, Jin-Yong; Yu, Seung-Do; Hong, Young-Seoub

    2014-09-01

    Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a recent World Health Organization report, arsenic from contaminated water can be quickly and easily absorbed and depending on its metabolic form, may adversely affect human health. Recently, the US Food and Drug Administration regulations for metals found in cosmetics to protect consumers against contaminations deemed deleterious to health; some cosmetics were found to contain a variety of chemicals including heavy metals, which are sometimes used as preservatives. Moreover, developing countries tend to have a growing number of industrial factories that unfortunately, harm the environment, especially in cities where industrial and vehicle emissions, as well as household activities, cause serious air pollution. Air is also an important source of arsenic exposure in areas with industrial activity. The presence of arsenic in airborne particulate matter is considered a risk for certain diseases. Taken together, various potential pathways of arsenic exposure seem to affect humans adversely, and future efforts to reduce arsenic exposure caused by environmental factors should be made.

  16. ARSENIC SPECIATION ANALYSIS IN HUMAN SALIVA

    Science.gov (United States)

    Background: Determination of arsenic species in human saliva is potentially useful for biomonitoring of human exposure to arsenic and for studying arsenic metabolism. However, there is no report on the speciation analysis of arsenic in saliva. Methods: Arsenic species in saliva ...

  17. Arsenic determination in water supplies for human consumption of the province of Cartago, Costa Rica

    International Nuclear Information System (INIS)

    Scientific knowledge about hydroarsenicism must be disclosed in Latin America. The presence of arsenic has been detected in waters of Costa Rica that have been used for human consumption, in areas of risk; specifically in the province of Cartago, in the cantons of Oreamuno, Central, Paraiso and Alvarado. A quantification of reduced form trivalent arsenic was performed with the methodology of the 7062 Environmental Protection Agency of the United States, through volatile metal hydride generation by flame atomic absorption. The analyzed samples have determined that maintaining the maximum extent permitted by current legislation Costa Rican, 10μg/L. Research areas have corresponded to areas of high risk for its volcanic nature. The vast water supply of the cantons under study, with areas of relative protection circling recharge areas of springs, has caused the population to consume water source underground, but surface direct influence, less influence of volcanic rocks that are found at greater depths. (author)

  18. Chemical Hydride Slurry for Hydrogen Production and Storage

    Energy Technology Data Exchange (ETDEWEB)

    McClaine, Andrew W

    2008-09-30

    The purpose of this project was to investigate and evaluate the attractiveness of using a magnesium chemical hydride slurry as a hydrogen storage, delivery, and production medium for automobiles. To fully evaluate the potential for magnesium hydride slurry to act as a carrier of hydrogen, potential slurry compositions, potential hydrogen release techniques, and the processes (and their costs) that will be used to recycle the byproducts back to a high hydrogen content slurry were evaluated. A 75% MgH2 slurry was demonstrated, which was just short of the 76% goal. This slurry is pumpable and storable for months at a time at room temperature and pressure conditions and it has the consistency of paint. Two techniques were demonstrated for reacting the slurry with water to release hydrogen. The first technique was a continuous mixing process that was tested for several hours at a time and demonstrated operation without external heat addition. Further work will be required to reduce this design to a reliable, robust system. The second technique was a semi-continuous process. It was demonstrated on a 2 kWh scale. This system operated continuously and reliably for hours at a time, including starts and stops. This process could be readily reduced to practice for commercial applications. The processes and costs associated with recycling the byproducts of the water/slurry reaction were also evaluated. This included recovering and recycling the oils of the slurry, reforming the magnesium hydroxide and magnesium oxide byproduct to magnesium metal, hydriding the magnesium metal with hydrogen to form magnesium hydride, and preparing the slurry. We found that the SOM process, under development by Boston University, offers the lowest cost alternative for producing and recycling the slurry. Using the H2A framework, a total cost of production, delivery, and distribution of $4.50/kg of hydrogen delivered or $4.50/gge was determined. Experiments performed at Boston

  19. Simultaneous Heat and Mass Transfer in DU Hydriding

    International Nuclear Information System (INIS)

    The sources of nuclear fusion reaction are deuterium (D) and tritium (T). Generally, D is fused into T, which generates helium atoms and neutrons. At this time, a tremendous amount of energy is generated. D + T → 4He + n (E = 17.6 MeV) Hydrogen is a gas, and cannot be stored in large amounts. In addition, it can be explosive. Therefore, one of the storing methods for hydrogen is metal hydride. In this research, several kinds of metal hydrides including U, Zr, ZrCo, ZrNi, and LaNi5 have been simulated through modeling work of hydrogen absorption, desorption, and pressure effect in a bed using DU. For the exact modeling of the hydriding process, it is necessary to calculate simultaneous heat and mass transfer because, in the hydriding process, not only is hydrogen gas transported by mass transport and chemisorption but heat transfer also occurs through absorption. Therefore, in this paper, we tried to calculate the simultaneous heat and mass transfer using numerical analysis methods. Simultaneous heat and mass transfer in DU hydriding is well fitted compared to the experimental data, and is more reasonable considering only one variable. The hydriding process changes the temperature and atomic ratio simultaneously, and thus it is necessary to consider in company with two transport phenomena. The numerical analysis method applied Euler's method; however, the Runge-Kutta method is a more widely used numerical solution of a differential equation. Therefore, when analyzing the hydriding process, Runge-Kutta or another method will henceforth be applied

  20. Reactions of NO with nitrogen hydrides x

    Science.gov (United States)

    Mebel, A. M.; Lin, M. C.

    In this review, we consider the reactions of NO ( x 1,2) with the nitrogen x hydrides NH, NH and NH . The reactions are relevant to the post-combustion, non-catalytic reduction of NO with NH in the thermal de-NO process and with x x HNCO in the rapid reduction of NO as well as to the thermal decomposition of x some high-energy materials, including ammonium dinitramide. The practical importance has motivated considerable theoretical interest in these reactions. We review numerous ab - initio molecular orbital studies of potential energy surfaces for NO NH and theoretical calculations of their kinetic parameters, such as x y thermal rate constants and branching ratios of various products. The most advanced theoretical calculations are carried out using the Gaussian-2 family of methods which provides the chemical accuracy (within 2 kcal mol ) for the energetics and molecular parameters of the reactants, products, intermediates and transition states. We present a detailed comparison of the theoretical results with available experimental data. We show that the reactions of NO with NH and NH x are very fast because they occur without a barrier and lead to the formation of multiple products which include radicals and stable molecules. The reactions of NO with NH , taking place by the H abstraction to form NH and HNO , are slow x x but still relevant to the NH de-NO system, because of their fast reverse processes x which have not yet been measured experimentally.

  1. Acute and chronic arsenic toxicity.

    Science.gov (United States)

    Ratnaike, R N

    2003-07-01

    Arsenic toxicity is a global health problem affecting many millions of people. Contamination is caused by arsenic from natural geological sources leaching into aquifers, contaminating drinking water and may also occur from mining and other industrial processes. Arsenic is present as a contaminant in many traditional remedies. Arsenic trioxide is now used to treat acute promyelocytic leukaemia. Absorption occurs predominantly from ingestion from the small intestine, though minimal absorption occurs from skin contact and inhalation. Arsenic exerts its toxicity by inactivating up to 200 enzymes, especially those involved in cellular energy pathways and DNA synthesis and repair. Acute arsenic poisoning is associated initially with nausea, vomiting, abdominal pain, and severe diarrhoea. Encephalopathy and peripheral neuropathy are reported. Chronic arsenic toxicity results in multisystem disease. Arsenic is a well documented human carcinogen affecting numerous organs. There are no evidence based treatment regimens to treat chronic arsenic poisoning but antioxidants have been advocated, though benefit is not proven. The focus of management is to reduce arsenic ingestion from drinking water and there is increasing emphasis on using alternative supplies of water.

  2. Arsenic and cardiovascular diseases

    Directory of Open Access Journals (Sweden)

    Bianchi F.

    2013-04-01

    Full Text Available A growing body of epidemiologic, experimental and clinical evidence shows that arsenic may exert relevant cardiovascular effects with early damage such as endothelial dysfunction. Early biomarkers of cardiovascular damage together with markers of exposure, genetic and epigenetic effects, DNA damage, apoptosis, oxidative stress remain unexplored and a study is ongoing in Italy.

  3. Effects of exogenous glutathione on arsenic burden and NO metabolism in brain of mice exposed to arsenite through drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan [China Medical University, Department of Environmental and Occupational Health, School of Public Health, Heping District, Shenyang, Liaoning (China); Liaoning University of Traditional Chinese Medicine, Department of Public Health Management, School of Professional Technology, Shenyang, Liaoning (China); Zhao, Fenghong; Jin, Yaping; Zhong, Yuan; Yu, Xiaoyun; Li, Gexin; Lv, Xiuqiang; Sun, Guifan [China Medical University, Department of Environmental and Occupational Health, School of Public Health, Heping District, Shenyang, Liaoning (China)

    2011-03-15

    Chronic exposure to inorganic arsenic (iAs) is associated with neurotoxicity. Studies to date have disclosed that methylation of ingested iAs is the main metabolic pathway, and it is a process relying on reduced glutathione (GSH). The aim of this study was to explore the effects of exogenous GSH on arsenic burden and metabolism of nitric oxide (NO) in the brain of mice exposed to arsenite via drinking water. Mice were exposed to sodium arsenite through drinking water contaminated with 50 mg/L arsenic for 4 weeks and treated intraperitoneally with saline solution, 200 mg/kg body weight (b.w), 400 mg/kg b.w, or 800 mg/kg b.w GSH, respectively, at the 4th week. Levels of iAs, monomethylarsenic acid, and dimethylarsenic acid (DMAs) in the liver, blood, and brain were determined by method of hydride generation coupled with atomic absorption spectrophotometry. Activities of nitric oxide synthase (NOS) and contents of NO in the brain were determined by colorimetric method. Compared with mice exposed to arsenite alone, administration of GSH increased dose-dependently the primary and secondary methylation ratio in the liver, which caused the decrease in percent iAs and increase in percent DMAs in the liver, as a consequence, resulted in significant decrease in iAs levels in the blood and total arsenic levels in both blood and brain. NOS activities and NO levels in the brain of mice in iAs group were significantly lower than those in control; however, administration of GSH could increase significantly activities of NOS and contents of NO. Findings from this study suggested that exogenous GSH could promote both primary and secondary arsenic methylation capacity in the liver, which might facilitate excretion of arsenicals, and consequently reduce arsenic burden in both blood and brain and furthermore ameliorate the effects of arsenicals on NO metabolism in the brain. (orig.)

  4. Micro-scale fracture experiments on zirconium hydrides and phase boundaries

    Science.gov (United States)

    Chan, H.; Roberts, S. G.; Gong, J.

    2016-07-01

    Fracture properties of micro-scale zirconium hydrides and phase boundaries were studied using microcantilever testing methods. FIB-machined microcantilevers were milled on cross-sectional surfaces of hydrided samples, with the most highly-stressed regions within the δ-hydride film, within the α-Zr or along the Zr-hydride interface. Cantilevers were notched using the FIB and then tested in bending using a nanoindenter. Load-displacement results show that three types of cantilevers have distinct deformation properties. Zr cantilevers deformed plastically. Hydride cantilevers fractured after a small amount of plastic flow; the fracture toughness of the δ-hydride was found to be 3.3 ± 0.4 MPam1/2 and SEM examination showed transgranular cleavage on the fracture surfaces. Cantilevers notched at the Zr-hydride interface developed interfacial voids during loading, at loads considerably lower than that which initiate brittle fracture of hydrides.

  5. Numerical simulation and performance test of metal hydride hydrogen storage system

    Directory of Open Access Journals (Sweden)

    Tzu-Hsiang Yen, Bin-Hao Chen, Bao-Dong Chen

    2011-05-01

    Full Text Available Metal hydride reactors are widely used in many industrial applications, such as hydrogen storage, thermal compression, heat pump, etc. According to the research requirement of metal hydride hydrogen storage, the thermal analyses have been implemented in the paper. The metal hydride reaction beds are considered as coupled cylindrical tube modules which combine the chemical absorption and desorption in metal hydride. The model is then used metal hydride LaNi5 as an example to predict the performance of metal hydride hydrogen storage devices, such as the position of hydration front and the thermal flux. Under the different boundary condition the characteristics of heat transfer and mass transfer in metal hydride have influence on the hydrogen absorption and desorption. The researches revealed that the scroll design can improve the temperature distribution in the reactor and the porous tube for directing hydrogen can increase the penetration depth of hydride reaction to decrease the hydrogen absorption time.

  6. Multidimensional simulations of hydrides during fuel rod lifecycle

    Science.gov (United States)

    Stafford, D. S.

    2015-11-01

    In light water reactor fuel rods, waterside corrosion of zirconium-alloy cladding introduces hydrogen into the cladding, where it is slightly soluble. When the solubility limit is reached, the hydrogen precipitates into crystals of zirconium hydride which decrease the ductility of the cladding and may lead to cladding failure during dry storage or transportation events. The distribution of the hydride phase and the orientation of the crystals depend on the history of the spatial temperature and stress profiles in the cladding. In this work, we have expanded the existing hydride modeling capability in the BISON fuel performance code with the goal of predicting both global and local effects on the radial, azimuthal and axial distribution of the hydride phase. We compare results from 1D simulations to published experimental data. We demonstrate the new capability by simulating in 2D a fuel rod throughout a lifecycle that includes irradiation, short-term storage in the spent fuel pool, drying, and interim storage in a dry cask. Using the 2D simulations, we present qualitative predictions of the effects of the inter-pellet gap and the drying conditions on the growth of a hydride rim.

  7. Sodium-based hydrides for thermal energy applications

    Science.gov (United States)

    Sheppard, D. A.; Humphries, T. D.; Buckley, C. E.

    2016-04-01

    Concentrating solar-thermal power (CSP) with thermal energy storage (TES) represents an attractive alternative to conventional fossil fuels for base-load power generation. Sodium alanate (NaAlH4) is a well-known sodium-based complex metal hydride but, more recently, high-temperature sodium-based complex metal hydrides have been considered for TES. This review considers the current state of the art for NaH, NaMgH3- x F x , Na-based transition metal hydrides, NaBH4 and Na3AlH6 for TES and heat pumping applications. These metal hydrides have a number of advantages over other classes of heat storage materials such as high thermal energy storage capacity, low volume, relatively low cost and a wide range of operating temperatures (100 °C to more than 650 °C). Potential safety issues associated with the use of high-temperature sodium-based hydrides are also addressed.

  8. The effect of stress state on zirconium hydride reorientation

    Science.gov (United States)

    Cinbiz, Mahmut Nedim

    Prior to storage in a dry-cask facility, spent nuclear fuel must undergo a vacuum drying cycle during which the spent fuel rods are heated up to elevated temperatures of ≤ 400°C to remove moisture the canisters within the cask. As temperature increases during heating, some of the hydride particles within the cladding dissolve while the internal gas pressure in fuel rods increases generating multi-axial hoop and axial stresses in the closed-end thin-walled cladding tubes. As cool-down starts, the hydrogen in solid solution precipitates as hydride platelets, and if the multiaxial stresses are sufficiently large, the precipitating hydrides reorient from their initial circumferential orientation to radial orientation. Radial hydrides can severely embrittle the spent nuclear fuel cladding at low temperature in response to hoop stress loading. Because the cladding can experience a range of stress states during the thermo-mechanical treatment induced during vacuum drying, this study has investigated the effect of stress state on the process of hydride reorientation during controlled thermo-mechanical treatments utilizing the combination of in situ X-ray diffraction and novel mechanical testing analyzed by the combination of metallography and finite element analysis. The study used cold worked and stress relieved Zircaloy-4 sheet containing approx. 180 wt. ppm hydrogen as its material basis. The failure behavior of this material containing radial hydrides was also studied over a range of temperatures. Finally, samples from reactor-irradiated cladding tubes were examined by X-ray diffraction using synchrotron radiation. To reveal the stress state effect on hydride reorientation, the critical threshold stress to reorient hydrides was determined by designing novel mechanical test samples which produce a range of stress states from uniaxial to "near-equibiaxial" tension when a load is applied. The threshold stress was determined after thermo-mechanical treatments by

  9. Rural methods to mitigate arsenic contaminated water

    OpenAIRE

    Parajuli, Krishna

    2013-01-01

    Consumption of arsenic contaminated water is one of the burning issues in the rural world. Poor public awareness program about health effects of drinking arsenic contaminated water and the rural methods to mitigate this problem poses a great threat of arsenic poisoning many people of the rural world. In this thesis, arsenic removal efficiency and the working mechanism of four rural and economical arsenic mitigation technologies i.e. solar oxidation and reduction of arsenic (SORAS), Bucket tr...

  10. Persistent Exposure to Arsenic via Drinking Water in Rural Bangladesh Despite Major Mitigation Efforts

    Science.gov (United States)

    Gardner, Renee; Hamadani, Jena; Grandér, Margaretha; Tofail, Fahmida; Nermell, Barbro; Palm, Brita; Kippler, Maria

    2011-01-01

    Objectives. Elevated arsenic levels in tube-well water in Bangladesh have prompted extensive mitigation projects. We evaluated the effectiveness of long-term mitigation efforts by longitudinally measuring arsenic exposure in pregnant women and their children, the most susceptible population groups. Methods. The study was nested in a population-based nutrition intervention in Matlab, Bangladesh. Mother–child pairs (n = 1951) were followed from 2001 to 2003, beginning in early gestation and continuing to 5 years postpartum. We measured arsenic concentrations in urine (U-As) of the 5-year-old children by using high-performance liquid chromatography online with hydride generation and inductively coupled plasma mass spectrometry and compared them with earlier childhood U-As and maternal U-As during pregnancy. Results. Children had elevated U-As at 5 years old (median = 51 μg/L, 5th–95th percentiles = 16–355 μg/L), and U-As distribution was similar to that observed in the mothers during gestation. Children's U-As at 5 years old significantly correlated with their U-As at 1.5 years old and to maternal U-As during early and late gestation. Conclusions. Despite major mitigation efforts, arsenic exposure remains highly elevated in rural Bangladesh. Further mitigation strategies are required and must be rigorously evaluated for long-term efficacy. PMID:21778503

  11. Arsenic enrichment in mangroves, and sediments along Karachi coast, Pakistan

    Institute of Scientific and Technical Information of China (English)

    Rashida Parveen; Erum Zahir; Arshad Fazal Siddiqui

    2013-01-01

    Objective: To assess the arsenic (As) concentration in different parts of mangroves Avicenniamarina and sediments in Karachi coastal area i.e. Korangi Creek , Manora, Kakapir and Sandspit. Methods: Sites are identified for sampling owing to their vicinity to industrial activities. Sandspit is targeted for its being devoid of industries. The hydride generation atomic absorption spectrometry (HG-AAS) were used to analyse the concentration of arsenic in mangrove and sediment.Results:The high concentration of As was found in roots and middle aerial part as compared to the upper part of mangroves. The concentrations of As was found higher in sediments as compared to the mangroves. There is a seasonal variation of As enrichment in mangrove and sediments as dry seasons showed higher concentration while in rainy season dilution factors may be attributed to the low level of As. The concentration variation of As in sampling sites of mangroves and sediments following the trend i.e. Korangi Creek >Manora>Kakapir>Sandspit. The statistical analysis (Two way ANOVA) of data exhibited no significant difference (P>0.05) for trace metals concentrations in mangrove as well as in sediments.Conclusions:It is obvious to conclude that As should be continuously monitored in different environmental segments. The data must correlate with geographical distribution of As, quantification in different species, their solubility and bioavailability to understand the possible factors responsible for environmental pollution. The present study will be helpful to improve water management resources.

  12. Arsenic enrichment in mangroves, and sediments along Karachi coast, Pakistan

    Directory of Open Access Journals (Sweden)

    Rashida Parveen

    2013-08-01

    Full Text Available Objective: To assess the arsenic (As concentration in different parts of mangroves Avicennia marina and sediments in Karachi coastal area i.e. Korangi Creek , Manora, Kakapir and Sandspit. Methods: Sites are identified for sampling owing to their vicinity to industrial activities. Sandspit is targeted for its being devoid of industries. The hydride generation atomic absorption spectrometry (HG-AAS were used to analyse the concentration of arsenic in mangrove and sediment. Results: The high concentration of As was found in roots and middle aerial part as compared to the upper part of mangroves. The concentrations of As was found higher in sediments as compared to the mangroves. There is a seasonal variation of As enrichment in mangrove and sediments as dry seasons showed higher concentration while in rainy season dilution factors may be attributed to the low level of As. The concentration variation of As in sampling sites of mangroves and sediments following the trend i.e. Korangi Creek >Manora>Kakapir>Sandspit. The statistical analysis (Two way ANOVA of data exhibited no significant difference (P>0.05 for trace metals concentrations in mangrove as well as in sediments. Conclusions: It is obvious to conclude that As should be continuously monitored in different environmental segments. The data must correlate with geographical distribution of As, quantification in different species, their solubility and bioavailability to understand the possible factors responsible for environmental pollution. The present study will be helpful to improve water management resources.

  13. Chronic arsenic poisoning from burning high-arsenic-containing coal in Guizhou, China.

    OpenAIRE

    Liu, Jie; Zheng, Baoshan; Aposhian, H. Vasken; Zhou, Yunshu; Chen, Ming-liang; Zhang, Aihua; Waalkes, Michael P.

    2002-01-01

    Arsenic is an environmental hazard and the reduction of drinking water arsenic levels is under consideration. People are exposed to arsenic not only through drinking water but also through arsenic-contaminated air and food. Here we report the health effects of arsenic exposure from burning high arsenic-containing coal in Guizhou, China. Coal in this region has undergone mineralization and thus produces high concentrations of arsenic. Coal is burned inside the home in open pits for daily cooki...

  14. High-Spin Cobalt Hydrides for Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Holland, Patrick L. [Yale University

    2013-08-29

    Organometallic chemists have traditionally used catalysts with strong-field ligands that give low-spin complexes. However, complexes with a weak ligand field have weaker bonds and lower barriers to geometric changes, suggesting that they may lead to more rapid catalytic reactions. Developing our understanding of high-spin complexes requires the use of a broader range of spectroscopic techniques, but has the promise of changing the mechanism and/or selectivity of known catalytic reactions. These changes may enable the more efficient utilization of chemical resources. A special advantage of cobalt and iron catalysts is that the metals are more abundant and cheaper than those currently used for major industrial processes that convert unsaturated organic molecules and biofeedstocks into useful chemicals. This project specifically evaluated the potential of high-spin cobalt complexes for small-molecule reactions for bond rearrangement and cleavage reactions relevant to hydrocarbon transformations. We have learned that many of these reactions proceed through crossing to different spin states: for example, high-spin complexes can flip one electron spin to access a lower-energy reaction pathway for beta-hydride elimination. This reaction enables new, selective olefin isomerization catalysis. The high-spin cobalt complexes also cleave the C-O bond of CO2 and the C-F bonds of fluoroarenes. In each case, the detailed mechanism of the reaction has been determined. Importantly, we have discovered that the cobalt catalysts described here give distinctive selectivities that are better than known catalysts. These selectivities come from a synergy between supporting ligand design and electronic control of the spin-state crossing in the reactions.

  15. Iron Hydride Detection and Intramolecular Hydride Transfer in a Synthetic Model of Mono-Iron Hydrogenase with a CNS Chelate.

    Science.gov (United States)

    Durgaprasad, Gummadi; Xie, Zhu-Lin; Rose, Michael J

    2016-01-19

    We report the identification and reactivity of an iron hydride species in a synthetic model complex of monoiron hydrogenase. The hydride complex is derived from a phosphine-free CNS chelate that includes a Fe-C(NH)(═O) bond (carbamoyl) as a mimic of the active site iron acyl. The reaction of [((O═)C(HN)N(py)S(Me))Fe(CO)2(Br)] (1) with NaHBEt3 generates the iron hydride intermediate [((O═)C(HN)N(py)S(Me))Fe(H)(CO)2] (2; δFe-H = -5.08 ppm). Above -40 °C, the hydride species extrudes CH3S(-) via intramolecular hydride transfer, which is stoichiometrically trapped in the structurally characterized dimer μ2-(CH3S)2-[((O═)C(HN)N(Ph))Fe(CO)2]2 (3). Alternately, when activated by base ((t)BuOK), 1 undergoes desulfurization to form a cyclometalated species, [((O═)C(NH)NC(Ph))Fe(CO)2] (5); derivatization of 5 with PPh3 affords the structurally characterized species [((O═)C(NH)NC)Fe(CO)(PPh3)2] (6), indicating complex 6 as the common intermediate along each pathway of desulfurization.

  16. A new heat storage system using metal hydrides

    Science.gov (United States)

    Ono, S.; Kawamura, M.; Ishido, Y.; Akiba, E.; Higano, S.

    The development of a prototype chemical heat storage system, designed for the accumulation of fairly high temperature (300 - 400 C) waste heat, and called the Hydriding Heat Storage system is presented. Mg2Ni hydride is used as the high temperature heat storing medium, and LaNi5H6 is used as a reservoir for the hydrogen released from the heat storing medium. The system has been in development since 1976, and a 2000 kcal heat capacity prototype system is to be completed by 1982. Basic investigations, i.e., reaction kinetics of absorption and desorption, and heat transfer characteristics of the hydride and/or the metal powder packed bed, are described.

  17. Kinetic and structural aspects of tantalum hydride formation

    Directory of Open Access Journals (Sweden)

    R. DIMITRIJEVIC

    2003-09-01

    Full Text Available Tantalum hydrides of various composition were synthesized by equilibrating tantalum with hydrogen at six different temperatures from 573 to 823 K, under a constant hydrogen pressure of 1 bar. Both the exact Ta/H mole ratios and the kinetic parameters of hydriding were determined on the basis of the dependence of the H/Ta mole ratio on time. The influence of stoichiometry on the appearance of X-ray powder diffractograms at room temperature was studied. As a consequence of hydriding, for ratios H/Ta > 0.2, the original bcc Ta-lattice undergoes distortion, manifesting itself as both a shift and a splitting of the X-ray patterns in the X-ray diffractograms. For samples with H/Ta < 0.2, the appearance of some superstructure reflections at low Bragg angles was noted, which suggests a long range ordering of hydrogen with orthorhombic symmetry.

  18. Theoretical Estimate of Hydride Affinities of Aromatic Carbonyl Compounds

    Institute of Scientific and Technical Information of China (English)

    AI Teng; ZHU Xiao-Qing; CHENG Jin-Pei

    2003-01-01

    @@ Aromatic carbonyl compounds are one type of the most important organic compounds, and the reductions ofthem by hydride agents such as LiAlH4 or NaBH4 are widely used in organic synthesis. The reactivity of carbonyl compounds generally increases in the following order: ketone < aldehyde, and amide < acid < ester < acid halide, which could be related to their hydride affinities (HA). In the previous paper, Robert[1] calculated the absolute HAof a series of small non-aromatic carbonyl compounds. In this paper, we use DFT method at B3LYP/6-311 + + G (2d, 2p)∥B3LYP/6-31 + G* level to estimate hydride affinities of five groups of aromatic carbonyl compounds. The detailed results are listed in Table 1.

  19. Moonshine-related arsenic poisoning.

    Science.gov (United States)

    Gerhardt, R E; Crecelius, E A; Hudson, J B

    1980-02-01

    Twelve sequential cases of arsenic poisoning were reviewed for possible sources of ingestion. Contaminated illicit whiskey (moonshine) appeared to be the source in approximately 50% of the patients. An analysis of.confiscated moonshine revealed that occasional specimens contained high levels of arsenic as a contaminant. Although arsenic poisoning occurs relatively infrequently, contaminated moonshine may be an important cause of the poisoning in some areas of the country.

  20. Arsenic poisoning of Bangladesh groundwater

    Science.gov (United States)

    Nickson, Ross; McArthur, John; Burgess, William; Ahmed, Kazi Matin; Ravenscroft, Peter; Rahmanñ, Mizanur

    1998-09-01

    In Bangladesh and West Bengal, alluvial Ganges aquifers used for public water supply are polluted with naturally occurring arsenic, which adversely affects the health of millions of people. Here we show that the arsenic derives from the reductive dissolution of arsenic-rich iron oxyhydroxides, which in turn are derived from weathering of base-metal sulphides. This finding means it should now be possible, by sedimentological study of the Ganges alluvial sediments, to guide the placement of new water wells so they will be free of arsenic.

  1. Arsenic content of homeopathic medicines

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, H.D.; Saryan, L.A.

    1986-01-01

    In order to test the widely held assumption that homeopathic medicines contain negligible quantities of their major ingredients, six such medicines labeled in Latin as containing arsenic were purchased over the counter and by mail order and their arsenic contents measured. Values determined were similar to those expected from label information in only two of six and were markedly at variance in the remaining four. Arsenic was present in notable quantities in two preparations. Most sales personnel interviewed could not identify arsenic as being an ingredient in these preparations and were therefore incapable of warning the general public of possible dangers from ingestion. No such warnings appeared on the labels.

  2. Photoelectron spectroscopy of boron aluminum hydride cluster anions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Gantefoer, Gerd; Bowen, Kit H., E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Li, Xiang [Center for Space Science and Technology, University of Maryland–Baltimore County, Baltimore, Maryland 21250 (United States); Kiran, Boggavarapu, E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry and Physics, McNeese State University, Lake Charles, Louisiana 70609 (United States); Kandalam, Anil K. [Department of Physics, West Chester University, West Chester, Pennsylvania 19383 (United States)

    2014-04-28

    Boron aluminum hydride clusters are studied through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations. Boron aluminum hydride cluster anions, B{sub x}Al{sub y}H{sub z}{sup −}, were generated in a pulsed arc cluster ionization source and identified by time-of-flight mass spectrometry. After mass selection, their photoelectron spectra were measured by a magnetic bottle-type electron energy analyzer. The resultant photoelectron spectra as well as calculations on a selected series of stoichiometries reveal significant geometrical changes upon substitution of aluminum atoms by boron atoms.

  3. Ab-initio study of transition metal hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Ramesh [Dept. of Physics, Feroze Gandhi Insititute of Engineering and Technology, Raebareli-229001 (India); Shukla, Seema, E-mail: sharma.yamini62@gmail.com; Dwivedi, Shalini, E-mail: sharma.yamini62@gmail.com; Sharma, Yamini, E-mail: sharma.yamini62@gmail.com [Theoretical Condensed Matter Physics Laboratory, Dept. of Physics Feroze Gandhi College, Raebareli-229001 (India)

    2014-04-24

    We have performed ab initio self consistent calculations based on Full potential linearized augmented plane wave (FP-LAPW) method to investigate the optical and thermal properties of yttrium hydrides. From the band structure and density of states, the optical absorption spectra and specific heats have been calculated. The band structure of Yttrium metal changes dramatically due to hybridization of Y sp orbitals with H s orbitals and there is a net charge transfer from metal to hydrogen site. The electrical resistivity and specific heats of yttrium hydrides are lowered but the thermal conductivity is slightly enhanced due to increase in scattering from hydrogen sites.

  4. Chemical Hydride Slurry for Hydrogen Production and Storage

    Energy Technology Data Exchange (ETDEWEB)

    McClaine, Andrew W

    2008-09-30

    The purpose of this project was to investigate and evaluate the attractiveness of using a magnesium chemical hydride slurry as a hydrogen storage, delivery, and production medium for automobiles. To fully evaluate the potential for magnesium hydride slurry to act as a carrier of hydrogen, potential slurry compositions, potential hydrogen release techniques, and the processes (and their costs) that will be used to recycle the byproducts back to a high hydrogen content slurry were evaluated. A 75% MgH2 slurry was demonstrated, which was just short of the 76% goal. This slurry is pumpable and storable for months at a time at room temperature and pressure conditions and it has the consistency of paint. Two techniques were demonstrated for reacting the slurry with water to release hydrogen. The first technique was a continuous mixing process that was tested for several hours at a time and demonstrated operation without external heat addition. Further work will be required to reduce this design to a reliable, robust system. The second technique was a semi-continuous process. It was demonstrated on a 2 kWh scale. This system operated continuously and reliably for hours at a time, including starts and stops. This process could be readily reduced to practice for commercial applications. The processes and costs associated with recycling the byproducts of the water/slurry reaction were also evaluated. This included recovering and recycling the oils of the slurry, reforming the magnesium hydroxide and magnesium oxide byproduct to magnesium metal, hydriding the magnesium metal with hydrogen to form magnesium hydride, and preparing the slurry. We found that the SOM process, under development by Boston University, offers the lowest cost alternative for producing and recycling the slurry. Using the H2A framework, a total cost of production, delivery, and distribution of $4.50/kg of hydrogen delivered or $4.50/gge was determined. Experiments performed at Boston

  5. Homicidal arsenic poisoning.

    Science.gov (United States)

    Duncan, Andrew; Taylor, Andrew; Leese, Elizabeth; Allen, Sam; Morton, Jackie; McAdam, Julie

    2015-07-01

    The case of a 50-year-old man who died mysteriously after being admitted to hospital is reported. He had raised the possibility of being poisoned prior to his death. A Coroner's post-mortem did not reveal the cause of death but this was subsequently established by post-mortem trace element analysis of liver, urine, blood and hair all of which revealed very high arsenic concentrations.

  6. A Phytoremediation Strategy for Arsenic

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, Richard B.

    2005-06-01

    A Phytoremediation Strategy for Arsenic Progress Report May, 2005 Richard B. Meagher Principal Investigator Arsenic pollution affects the health of several hundred millions of people world wide, and an estimated 10 million Americans have unsafe levels of arsenic in their drinking water. However, few environmentally sound remedies for cleaning up arsenic contaminated soil and water have been proposed. Phytoremediation, the use of plants to extract and sequester environmental pollutants, is one new technology that offers an ecologically sound solution to a devastating problem. We propose that it is less disruptive to the environment to harvest and dispose of several thousand pounds per acre of contaminated aboveground plant material, than to excavate and dispose of 1 to 5 million pounds of contaminated soil per acre (assumes contamination runs 3 ft deep). Our objective is to develop a genetics-based phytoremediation strategy for arsenic removal that can be used in any plant species. This strategy requires the enhanced expression of several transgenes from diverse sources. Our working hypothesis is that organ-specific expression of several genes controlling the transport, electrochemical state, and binding of arsenic will result in the efficient extraction and hyperaccumulation of arsenic into aboveground plant tissues. This hypothesis is supported by theoretical arguments and strong preliminary data. We proposed six Specific Aims focused on testing and developing this arsenic phytoremediation strategy. During the first 18 months of the grant we made significant progress on five Specific Aims and began work on the sixth as summarized below. Specific Aim 1: Enhance plant arsenic resistance and greatly expand sinks for arsenite by expressing elevated levels of thiol-rich, arsenic-binding peptides. Hyperaccumulation of arsenic depends upon making plants that are both highly tolerant to arsenic and that have the capacity to store large amounts of arsenic aboveground

  7. Comparison of irradiation hardening and microstructure evolution in ion-irradiated delta and epsilon hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Oono, Naoko, E-mail: n-oono@eng.hokudai.ac.jp [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kasada, Ryuta [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Higuchi, Toru; Sakamoto, Kan; Nakatsuka, Masafumi [Nippon Nuclear Fuel Development Co., Ltd., 2163 Naritacho Oarai, Higashi-Ibaraki, Ibaraki 311-1313 (Japan); Hasegawa, Akiko; Kondo, Sosuke; Iwata, Noriyuki Y.; Matsui, Hideki; Kimura, Akihiko [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

    2013-11-15

    A δ-Zr-hydride was irradiated with 6.4 MeV Fe{sup 3+} ions to clarify the relationship between hardening and microstructural changes of bulk Zr-hydrides under neutron irradiation. Irradiation hardening was measured by nanoindentation tests. Transmission electron microscope cross-sectional observations showed that the deformation mechanism of the δ-Zr-hydride was both slip and twinning. Dislocation loops were observed in the irradiated hydride matrix. These irradiation-induced defects make slip deformation difficult and consequently promote the twin deformation of δ-Zr-hydride. This work is a continuation of the previous our work (J. Nucl. Mater. 419 (2011) 366–370) focused upon ε-Zr-hydride and we discuss a comparison between the two Zr-hydrides.

  8. Growth and decomposition of Lithium and Lithium hydride on Nickel

    DEFF Research Database (Denmark)

    Engbæk, Jakob; Nielsen, Gunver; Nielsen, Jane Hvolbæk;

    2006-01-01

    In this paper we have investigated the deposition, structure and decomposition of lithium and lithium-hydride films on a nickel substrate. Using surface sensitive techniques it was possible to quantify the deposited Li amount, and to optimize the deposition procedure for synthesizing lithium...

  9. Process of forming a sol-gel/metal hydride composite

    Science.gov (United States)

    Congdon, James W.

    2009-03-17

    An external gelation process is described which produces granules of metal hydride particles contained within a sol-gel matrix. The resulting granules are dimensionally stable and are useful for applications such as hydrogen separation and hydrogen purification. An additional coating technique for strengthening the granules is also provided.

  10. Structural deformation of metallic uranium surrounding hydride growth sites

    International Nuclear Information System (INIS)

    Highlights: • UH3 formation on uranium surfaces by a controlled uptake of hydrogen at 240 °C. • Large hydride growths (35–125 μm in diameter) form at the surface. • Confined hydride expansion during growth generates stress in the subsurface. • EBSD scans found micro-cracking and twins as forms of stress relief in the metal. - Abstract: Electron backscatter diffraction (EBSD) was utilised to probe the microstructure of uranium metal in the vicinity of surface corrosion pits, resulting from hydrogen exposure (5 × 104 Pa, at 240 °C). Microstructural analysis of the surface revealed a subtle increase of grain orientation variation for grains at the border of the hydride growths. Cross sectional analysis, at pit sites, revealed significant microstructure deformation in the form of crystal twinning and micro-cracking beneath the surface. These observations provide qualitative evidence that local stress intensities generated as a consequence of hydride growth and confinement, were sufficient to cause deformation within the parent metal

  11. Design and integration of a hydrogen storage on metallic hydrides

    International Nuclear Information System (INIS)

    This work presents a hydrogen storage system using metal hydrides for a Combined Heat and Power (CHP) system. Hydride storage technology has been chosen due to project specifications: high volumetric capacity, low pressures (≤ 3.5 bar) and low temperatures (≤ 75 C: fuel cell temperature). During absorption, heat from hydride generation is dissipated by fluid circulation. An integrated plate-fin type heat exchanger has been designed to obtain good compactness and to reach high absorption/desorption rates. At first, the storage system has been tested in accordance with project specifications (absorption 3.5 bar, desorption 1.5 bar). Then, the hydrogen charge/discharge times have been decreased to reach system limits. System design has been used to simulate thermal and mass comportment of the storage tank. The model is based on the software Fluent. We take in consideration heat and mass transfers in the porous media during absorption/desorption. The hydride thermal and mass behaviour has been integrated in the software. The heat and mass transfers experimentally obtained have been compared to results calculated by the model. The influence of experimental and numerical parameters on the model behaviour has also been explored. (author)

  12. Diffusion model of delayed hydride cracking in zirconium alloys

    NARCIS (Netherlands)

    Shmakov, AA; Kalin, BA; Matvienko, YG; Singh, RN; De, PK

    2004-01-01

    We develop a method for the evaluation of the rate of delayed hydride cracking in zirconium alloys. The model is based on the stationary solution of the phenomenological diffusion equation and the detailed analysis of the distribution of hydrostatic stresses in the plane of a sharp tensile crack. Th

  13. Electrochromism of Mg-Ni hydride switchable mirrors

    Science.gov (United States)

    Isidorsson, Jan; Giebels, I. A. M. E.; Di Vece, M.; Griessen, Ronald

    2001-11-01

    Switchable mirrors have so far been made of rare-earth and rare-earth-magnesium based metal-hydrides. In this investigation we study Mg-Ni-hydrides, which have been shown by Richardson et al. to exhibit switchable properties similar to those of the rare-earth hydrides. Cyclic voltammetry on MgzNiHx samples with 0.8 less than z less than 3.7 shows that addition of one Mg atom per Mg2Ni gives the best ab/desorption kinetics for hydrogen. X- ray diffraction reveals a structural change as hydrogen is absorbed. The metal-insulator transition is confirmed with simultaneous resistivity measurements. A pressure- composition isotherm of Mg2NiHx is also determined electrochemically. Optical spectrometry during gas loading gives an optical band gap of 1.6 eV for Mg2NiH4. This gap increases with increasing Mg content in a way similar to that of the Mg-doped rare-earth hydrides.

  14. Hydrogen Storage in Porous Materials and Magnesium Hydrides

    NARCIS (Netherlands)

    Grzech, A.

    2013-01-01

    In this thesis representatives of two different types of materials for potential hydrogen storage application are presented. Usage of either nanoporous materials or metal hydrides has both operational advantages and disadvantages. A main objective of this thesis is to characterize the hydrogen stora

  15. ARSENIC - SUSCEPTIBILITY & IN UTERO EFFECTS

    Science.gov (United States)

    Exposure to inorganic arsenic remains a serious public health problem at many locations worldwide. If has often been noted that prevalences of signs and symptoms of chronic arsenic poisoning differ among various populations. For example, skin lesions or peripheral vascular dis...

  16. Arsenic Mobility and Groundwater Extraction in Bangladesh

    Science.gov (United States)

    Harvey, Charles F.; Swartz, Christopher H.; Badruzzaman, A. B. M.; Keon-Blute, Nicole; Yu, Winston; Ali, M. Ashraf; Jay, Jenny; Beckie, Roger; Niedan, Volker; Brabander, Daniel; Oates, Peter M.; Ashfaque, Khandaker N.; Islam, Shafiqul; Hemond, Harold F.; Ahmed, M. Feroze

    2002-11-01

    High levels of arsenic in well water are causing widespread poisoning in Bangladesh. In a typical aquifer in southern Bangladesh, chemical data imply that arsenic mobilization is associated with recent inflow of carbon. High concentrations of radiocarbon-young methane indicate that young carbon has driven recent biogeochemical processes, and irrigation pumping is sufficient to have drawn water to the depth where dissolved arsenic is at a maximum. The results of field injection of molasses, nitrate, and low-arsenic water show that organic carbon or its degradation products may quickly mobilize arsenic, oxidants may lower arsenic concentrations, and sorption of arsenic is limited by saturation of aquifer materials.

  17. Synthesis of hydrides by interaction of intermetallic compounds with ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Tarasov, Boris P., E-mail: tarasov@icp.ac.ru [Institute of Problems of Chemical Physics of the Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Fokin, Valentin N.; Fokina, Evelina E. [Institute of Problems of Chemical Physics of the Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Yartys, Volodymyr A., E-mail: volodymyr.yartys@ife.no [Institute for Energy Technology, Kjeller NO 2027 (Norway); Department of Materials Science and Engineering, Norwegian University of Science and Technology, Trondheim NO 7491 (Norway)

    2015-10-05

    Highlights: • Interaction of the intermetallics A{sub 2}B, AB, AB{sub 2}, AB{sub 5} and A{sub 2}B{sub 17} with NH{sub 3} was studied. • The mechanism of interaction of the alloys with ammonia is temperature-dependent. • Hydrides, hydridonitrides, disproportionation products or metal–N–H compounds are formed. • NH{sub 4}Cl was used as an activator of the reaction between ammonia and intermetallics. • Interaction with ammonia results in the synthesis of the nanopowders. - Abstract: Interaction of intermetallic compounds with ammonia was studied as a processing route to synthesize hydrides and hydridonitrides of intermetallic compounds having various stoichiometries and types of crystal structures, including A{sub 2}B, AB, AB{sub 2}, AB{sub 5} and A{sub 2}B{sub 17} (A = Mg, Ti, Zr, Sc, Nd, Sm; B = transition metals, including Fe, Co, Ni, Ti and nontransition elements, Al and B). In presence of NH{sub 4}Cl used as an activator of the reaction between ammonia and intermetallic alloys, their interaction proceeds at rather mild P–T conditions, at temperatures 100–200 °C and at pressures of 0.6–0.8 MPa. The mechanism of interaction of the alloys with ammonia appears to be temperature-dependent and, following a rise of the interaction temperature, it leads to the formation of interstitial hydrides; interstitial hydridonitrides; disproportionation products (binary hydride; new intermetallic hydrides and binary nitrides) or new metal–nitrogen–hydrogen compounds like magnesium amide Mg(NH{sub 2}){sub 2}. The interaction results in the synthesis of the nanopowders where hydrogen and nitrogen atoms become incorporated into the crystal lattices of the intermetallic alloys. The nitrogenated materials have the smallest particle size, down to 40 nm, and a specific surface area close to 20 m{sup 2}/g.

  18. Arsenic concentrations in Chinese coals

    International Nuclear Information System (INIS)

    The arsenic concentrations in 297 coal samples were collected from the main coal-mines of 26 provinces in China were determined by molybdenum blue coloration method. These samples were collected from coals that vary widely in coal rank and coal-forming periods from the five main coal-bearing regions in China. Arsenic content in Chinese coals range between 0.24 to 71 mg/kg. The mean of the concentration of Arsenic is 6.4 ± 0.5 mg/kg and the geometric mean is 4.0 ± 8.5 mg/kg. The level of arsenic in China is higher in northeastern and southern provinces, but lower in northwestern provinces. The relationship between arsenic content and coal-forming period, coal rank is studied. It was observed that the arsenic contents decreases with coal rank in the order: Tertiary > Early Jurassic > Late Triassic > Late Jurassic > Middle Jurassic > Late Permian > Early Carboniferous > Middle Carboniferous > Late Carboniferous > Early Permian; It was also noted that the arsenic contents decrease in the order: Subbituminous > Anthracite > Bituminous. However, compared with the geological characteristics of coal forming region, coal rank and coal-forming period have little effect on the concentration of arsenic in Chinese coal. The average arsenic concentration of Chinese coal is lower than that of the whole world. The health problems in China derived from in coal (arsenism) are due largely to poor local life-style practices in cooking and home heating with coal rather than to high arsenic contents in the coal

  19. Synthesis and enhanced hydrogen desorption kinetics of magnesium hydride using hydriding chemical vapor synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin-Ho [Icheon Branch, Korea Institute of Ceramic Engineering and Technology (KICET), Icheon-si, Gyeonggi-do (Korea, Republic of); Kim, Byung-Goan [Korea Energy Materials Co.Ltd., 409, Daegu Technopark, 1-11, Hosan-Dong, Dalse-Gu 704-230 (Korea, Republic of); Kang, Yong-Mook, E-mail: dake@kaist.ac.kr [Department of Chemistry, Dongguk University-Seoul, 100715 Seoul (Korea, Republic of)

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer We synthesized pure MgH{sub 2} by a hydriding chemical vapor synthesis process in a hydrogen atmosphere. Black-Right-Pointing-Pointer The particle size HCVS-MgH{sub 2} was drastically reduced to the sub-micron or micrometer-scale. Black-Right-Pointing-Pointer HCVS-MgH{sub 2} showed different shapes (needle-like nanofibers and angulated plate) depending on the deposited position. Black-Right-Pointing-Pointer HCVS-MgH{sub 2} desorbed hydrogen up to about 7.2 wt% and 7.1 wt%. - Abstract: This paper describes the hydriding chemical vapor synthesis (HCVS) of the hydrogen storage alloy MgH{sub 2} in a hydrogen atmosphere and the product's hydrogenation properties. Mg powder was used as a starting material to produce submicron MgH{sub 2} and uniformly heated to a temperature of 600 Degree-Sign C for Mg vaporization. The effects of deposited positions in HCVS reactor on the morphology and the composition of the obtained products were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses. It is clearly seen that after the HCVS process, the particle size of synthesized MgH{sub 2} was drastically reduced to the sub-micron or micrometer-scale and these showed different shapes (needle-like nanofibers and angulated plate) depending on the deposited position. The hydrogen desorption temperatures of HCVS-MgH{sub 2} were measured using a differential scanning calorimeter (DSC). It was found that after the HCVS process, the desorption temperature of HCVS-MgH{sub 2} decreased from 430 to 385 Degree-Sign C and, simultaneously, the smallest particle size and the highest specific surface area were obtained. These observations indicate that the minimum hydrogen desorption temperature of HCVS-MgH{sub 2} powder with needle-like form can be obtained, and that this temperature is dependent on the particle size and the specific surface area of the products. The thermogravimetric

  20. Polymorphism of inflammatory genes and arsenic methylation capacity are associated with urothelial carcinoma

    International Nuclear Information System (INIS)

    Chronic exposure to arsenic can generate reactive oxidative species, which can induce certain proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8). TNF-α, IL-6 and IL-8 have been shown to be involved in the development and progression of various cancers, including bladder cancer. This study aimed to investigate the joint effect of the polymorphism of TNF-α − 308 G/A, IL-6 − 174 G/C, IL-8 − 251 T/A and urinary arsenic profiles on urothelial carcinoma (UC) risk. This study evaluated 300 pathologically-confirmed cases of UC and 594 cancer-free controls. Urinary arsenic species were detected using high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. The polymorphism of TNF-α − 308 G/A, IL-6 − 174 G/C and IL-8 − 251 T/A was determined using polymerase chain reaction-restriction fragment length polymorphism. The joint effects on UC risk were estimated by odds ratios and 95% confidence intervals using unconditional logistic regression. We found that the TNF-α − 308 A/A and IL-8 − 251 T/T polymorphisms were significantly associated with UC. Moreover, significant dose–response joint effect of TNF-α − 308 A/A or IL-8 − 251 T/T genotypes and arsenic methylation indices were seen to affect UC risk. The present results also showed a significant increase in UC risk in subjects with the IL-8 − 251 T/T genotype for each SD increase in urinary total arsenic and MMA%. In contrast, a significant decrease in UC risk was found in subjects who carried the IL-8 − 251 T/T genotype for each SD increase in DMA%. - Highlights: • Joint effect of the TNF-α -308 A/A genotype and urinary total arsenic affected UC. • Joint effect of the IL-8 -251 T/T genotype and urinary total arsenic affected UC. • Urinary total arsenic level, TNF-α -308 A/A and IL-8 -251 T/T genotype affected UC

  1. Polymorphism of inflammatory genes and arsenic methylation capacity are associated with urothelial carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chia-Chang [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Urology, Taipei Medical University—Shuang Ho Hospital, Taipei, Taiwan (China); Huang, Yung-Kai [School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan (China); Chung, Chi-Jung [Department of Health Risk Management, College of Public Health, China Medical University and Hospital, Taichung, Taiwan (China); Department of Medical Research, China Medical University Hospital, Taichung, Taiwan (China); Huang, Chao-Yuan; Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, College of Medicine National Taiwan University, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan (China); Lai, Li-An [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Lin, Ying-Chin [Department of Family Medicine, Shung Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Department of Health Examination, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan (China); Su, Chien-Tien [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2013-10-01

    Chronic exposure to arsenic can generate reactive oxidative species, which can induce certain proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8). TNF-α, IL-6 and IL-8 have been shown to be involved in the development and progression of various cancers, including bladder cancer. This study aimed to investigate the joint effect of the polymorphism of TNF-α − 308 G/A, IL-6 − 174 G/C, IL-8 − 251 T/A and urinary arsenic profiles on urothelial carcinoma (UC) risk. This study evaluated 300 pathologically-confirmed cases of UC and 594 cancer-free controls. Urinary arsenic species were detected using high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. The polymorphism of TNF-α − 308 G/A, IL-6 − 174 G/C and IL-8 − 251 T/A was determined using polymerase chain reaction-restriction fragment length polymorphism. The joint effects on UC risk were estimated by odds ratios and 95% confidence intervals using unconditional logistic regression. We found that the TNF-α − 308 A/A and IL-8 − 251 T/T polymorphisms were significantly associated with UC. Moreover, significant dose–response joint effect of TNF-α − 308 A/A or IL-8 − 251 T/T genotypes and arsenic methylation indices were seen to affect UC risk. The present results also showed a significant increase in UC risk in subjects with the IL-8 − 251 T/T genotype for each SD increase in urinary total arsenic and MMA%. In contrast, a significant decrease in UC risk was found in subjects who carried the IL-8 − 251 T/T genotype for each SD increase in DMA%. - Highlights: • Joint effect of the TNF-α -308 A/A genotype and urinary total arsenic affected UC. • Joint effect of the IL-8 -251 T/T genotype and urinary total arsenic affected UC. • Urinary total arsenic level, TNF-α -308 A/A and IL-8 -251 T/T genotype affected UC.

  2. Effect of organic matter amendment, arsenic amendment and water management regime on rice grain arsenic species

    International Nuclear Information System (INIS)

    Arsenic accumulation in rice grain has been identified as a major problem in some regions of Asia. A study was conducted to investigate the effect of increased organic matter in the soil on the release of arsenic into soil pore water and accumulation of arsenic species within rice grain. It was observed that high concentrations of soil arsenic and organic matter caused a reduction in plant growth and delayed flowering time. Total grain arsenic accumulation was higher in the plants grown in high soil arsenic in combination with high organic matter, with an increase in the percentage of organic arsenic species observed. The results indicate that the application of organic matter should be done with caution in paddy soils which have high soil arsenic, as this may lead to an increase in accumulation of arsenic within rice grains. Results also confirm that flooding conditions substantially increase grain arsenic. -- Highlights: ► High soil arsenic and organic matter caused a reduction in plant growth. ► A delayed flowering time was observed in high arsenic and organic matter soil. ► Total grain arsenic increased in high arsenic and organic matter soil. ► Percentage organic arsenic in the grain altered in arsenic and organic matter soil. -- The addition of high amounts of organic matter to soils led to an increase in total rice grain arsenic, as well as alteration in the percentage arsenic species in the rice grains

  3. Osteoresorptive arsenic intoxication.

    Science.gov (United States)

    Dani, Sergio Ulhoa

    2013-04-01

    A 47-year-old woman consulted her dermatologist complaining whole body dermatitis, urticaria and irritating bullous eruptions on the plantar and side surfaces of her feet. She had had multiple hypopigmented spots on her skin since her early adulthood. The patient was treated with topical medication without significant improvement of symptoms. One year later she suffered a myocardial infarction, accompanied by refractory anaemia. At the age of 49, a breast cancer was diagnosed and shortly thereafter her last menstruation occurred. At age 50years, upon complaint of weight loss despite normal food intake, Hashimoto thyroiditis with latent hyperthyroidism, vitamin D insufficiency with secondary hyperparathyroidism, and poikilocytic anaemia with anisochromia, hypochromia, anisocytosis, elliptocytes, drepanocytes, dacryocytes, acanthocytes, echinocytes, schizocytes, stomatocytes and target cells were diagnosed. The osteodensitometric and laboratory examinations revealed osteoporosis with sustained elevation of urinary Dipyridinolin-crosslinks (u-Dpd), and urinary arsenic (u-As) of 500μg/l (equivalent to 0.5 parts per million-ppm, 2.5μg/mg creatinine/dl, u-As: Phosphate of 26μg/mmol; the estimated bone As:P and As/kg body weight were 500μg/g and 11.3mg/kg, respectively). Thalassemia, immunoglobinopathy and iron deficiency were excluded. Supplementation with oral vitamin D and calcium, and antiresorptive therapy with intravenous zolendronate normalised the u-Dpd, significantly decreased the urinary arsenic concentration, and cured the anemia and the urticaria. A diagnosis of osteoresorptive arsenic intoxication (ORAI) was established. PMID:23337042

  4. Composite Materials for Hazard Mitigation of Reactive Metal Hydrides.

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, Joseph William; Cordaro, Joseph Gabriel; Sartor, George B.; Dedrick, Daniel E.; Reeder, Craig L.

    2012-02-01

    In an attempt to mitigate the hazards associated with storing large quantities of reactive metal hydrides, polymer composite materials were synthesized and tested under simulated usage and accident conditions. The composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride. Composites with vinyl-containing siloxane oligomers were also polymerized with and without added styrene and divinyl benzene. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride reduced the inherent hydrogen storage capacity of the material. The composites were found to be initially effective at reducing the amount of heat released during oxidation. However, upon cycling the composites, the mitigating behavior was lost. While the polymer composites we investigated have mitigating potential and are physically robust, they undergo a chemical change upon cycling that makes them subsequently ineffective at mitigating heat release upon oxidation of the metal hydride. Acknowledgements The authors would like to thank the following people who participated in this project: Ned Stetson (U.S. Department of Energy) for sponsorship and support of the project. Ken Stewart (Sandia) for building the flow-through calorimeter and cycling test stations. Isidro Ruvalcaba, Jr. (Sandia) for qualitative experiments on the interaction of sodium alanate with water. Terry Johnson (Sandia) for sharing his expertise and knowledge of metal hydrides, and sodium alanate in particular. Marcina Moreno (Sandia) for programmatic assistance. John Khalil (United Technologies Research Corp) for insight into the hazards of reactive metal hydrides and real-world accident scenario experiments. Summary In an attempt to mitigate and/or manage hazards associated with storing bulk quantities of reactive metal hydrides, polymer composite materials (a mixture of a mitigating polymer and a metal hydride) were synthesized and tested

  5. Microbial responses to environmental arsenic.

    Science.gov (United States)

    Páez-Espino, David; Tamames, Javier; de Lorenzo, Víctor; Cánovas, David

    2009-02-01

    Microorganisms have evolved dynamic mechanisms for facing the toxicity of arsenic in the environment. In this sense, arsenic speciation and mobility is also affected by the microbial metabolism that participates in the biogeochemical cycle of the element. The ars operon constitutes the most ubiquitous and important scheme of arsenic tolerance in bacteria. This system mediates the extrusion of arsenite out of the cells. There are also other microbial activities that alter the chemical characteristics of arsenic: some strains are able to oxidize arsenite or reduce arsenate as part of their respiratory processes. These type of microorganisms require membrane associated proteins that transfer electrons from or to arsenic (AoxAB and ArrAB, respectively). Other enzymatic transformations, such as methylation-demethylation reactions, exchange inorganic arsenic into organic forms contributing to its complex environmental turnover. This short review highlights recent studies in ecology, biochemistry and molecular biology of these processes in bacteria, and also provides some examples of genetic engineering for enhanced arsenic accumulation based on phytochelatins or metallothionein-like proteins.

  6. Removing arsenic from drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Hathaway, S.W.; Rubel, R. (Environmental Protection Agency, Cincinnati, OH (USA))

    1987-08-01

    Pilot-plant tests of two treatment methods, activated alumina and ion exchange, for removing arsenic from drinking water were evaluated at the Fallon, Nevada, Naval Air Station (NAS). The arsenic concentration was 0.080-0.116 mg/liter, exceeding the 0.05 mg/liter maximum contaminant level. Although the valence of arsenic was not determined, in prechlorination process and test results suggest it was probably arsenic V. Chlorinated drinking water from the NAS was used for evaluating the efficacy of treatment under several different conditions. The activated alumina and ion exchange systems were operated through three different loading and regeneration cycles each. The major water quality factors affecting the removal of arsenic by these methods were pH of feedwater, arsenic concentration, sulfate concentration, and alkalinity. The major operational factors affecting removal were flow rate, down time, and media clogging. Capital and operating costs for arsenic removal are estimated for the activated alumina method at optimum pH (5.5) for each of the three small community systems drawing water from the same aquifer. In addition, several containers of the regeneration waste were used for a special study to characterize, dewater, and render the waste non-toxic for disposal in a sanitary landfill.

  7. Factors Affecting Arsenic Methylation in Arsenic-Exposed Humans: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Shen, Hui; Niu, Qiang; Xu, Mengchuan; Rui, Dongsheng; Xu, Shangzhi; Feng, Gangling; Ding, Yusong; Li, Shugang; Jing, Mingxia

    2016-02-06

    Chronic arsenic exposure is a critical public health issue in many countries. The metabolism of arsenic in vivo is complicated because it can be influenced by many factors. In the present meta-analysis, two researchers independently searched electronic databases, including the Cochrane Library, PubMed, Springer, Embase, and China National Knowledge Infrastructure, to analyze factors influencing arsenic methylation. The concentrations of the following arsenic metabolites increase (parsenic exposure: inorganic arsenic (iAs), monomethyl arsenic (MMA), dimethyl arsenic (DMA), and total arsenic. Additionally, the percentages of iAs (standard mean difference (SMD): 1.00; 95% confidence interval (CI): 0.60-1.40; parsenic methylation, and arsenic methylation is more efficient in women than in men. The results of this analysis may provide information regarding the role of arsenic oxidative methylation in the arsenic poisoning process.

  8. Factors Affecting Arsenic Methylation in Arsenic-Exposed Humans: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Shen, Hui; Niu, Qiang; Xu, Mengchuan; Rui, Dongsheng; Xu, Shangzhi; Feng, Gangling; Ding, Yusong; Li, Shugang; Jing, Mingxia

    2016-02-01

    Chronic arsenic exposure is a critical public health issue in many countries. The metabolism of arsenic in vivo is complicated because it can be influenced by many factors. In the present meta-analysis, two researchers independently searched electronic databases, including the Cochrane Library, PubMed, Springer, Embase, and China National Knowledge Infrastructure, to analyze factors influencing arsenic methylation. The concentrations of the following arsenic metabolites increase (parsenic exposure: inorganic arsenic (iAs), monomethyl arsenic (MMA), dimethyl arsenic (DMA), and total arsenic. Additionally, the percentages of iAs (standard mean difference (SMD): 1.00; 95% confidence interval (CI): 0.60-1.40; parsenic methylation, and arsenic methylation is more efficient in women than in men. The results of this analysis may provide information regarding the role of arsenic oxidative methylation in the arsenic poisoning process.

  9. Arsenic speciation in edible alga samples by microwave-assisted extraction and high performance liquid chromatography coupled to atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Salgado, S. [Departamento de Ingenieria Civil: Tecnologia Hidraulica y Energetica, Escuela Universitaria de Ingenieria Tecnica de Obras Publicas, Universidad Politecnica de Madrid, Alfonso XII 3 y 5, 28014 Madrid (Spain); Quijano, M.A., E-mail: marian.quijano@upm.es [Departamento de Ingenieria Civil: Tecnologia Hidraulica y Energetica, Escuela Universitaria de Ingenieria Tecnica de Obras Publicas, Universidad Politecnica de Madrid, Alfonso XII 3 y 5, 28014 Madrid (Spain); Bonilla, M.M. [Departamento de Ingenieria Civil: Tecnologia Hidraulica y Energetica, Escuela Universitaria de Ingenieria Tecnica de Obras Publicas, Universidad Politecnica de Madrid, Alfonso XII 3 y 5, 28014 Madrid (Spain)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer Total As and As species were analyzed in edible marine algae. Black-Right-Pointing-Pointer A microwave-assisted extraction method with deionized water was applied. Black-Right-Pointing-Pointer As compounds identified comprised DMA, As(V) and four arsenosugars Black-Right-Pointing-Pointer Considerably high As(V) concentrations were found in the most of the algae studied. - Abstract: Twelve commercially available edible marine algae from France, Japan and Spain and the certified reference material (CRM) NIES No. 9 Sargassum fulvellum were analyzed for total arsenic and arsenic species. Total arsenic concentrations were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) after microwave digestion and ranged from 23 to 126 {mu}g g{sup -1}. Arsenic species in alga samples were extracted with deionized water by microwave-assisted extraction and showed extraction efficiencies from 49 to 98%, in terms of total arsenic. The presence of eleven arsenic species was studied by high performance liquid chromatography-ultraviolet photo-oxidation-hydride generation atomic-fluorescence spectrometry (HPLC-(UV)-HG-AFS) developed methods, using both anion and cation exchange chromatography. Glycerol and phosphate sugars were found in all alga samples analyzed, at concentrations between 0.11 and 22 {mu}g g{sup -1}, whereas sulfonate and sulfate sugars were only detected in three of them (0.6-7.2 {mu}g g{sup -1}). Regarding arsenic toxic species, low concentration levels of dimethylarsinic acid (DMA) (<0.9 {mu}g g{sup -1}) and generally high arsenate (As(V)) concentrations (up to 77 {mu}g g{sup -1}) were found in most of the algae studied. The results obtained are of interest to highlight the need to perform speciation analysis and to introduce appropriate legislation to limit toxic arsenic species content in these food products.

  10. Hazardous impact of arsenic on tissues of same fish species collected from two ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Abdul Qadir, E-mail: aqshah07@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Kazi, Tasneem Gul, E-mail: tgkazi@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Arain, Mohammad Balal, E-mail: bilal_KU2004@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Baig, Jameel Ahmed, E-mail: jab_mughal@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Afridi, Hassan Imran, E-mail: hassanimranafridi@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Kandhro, Ghulam Abbas, E-mail: gakandhro@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Khan, Sumaira, E-mail: skhanzai@gmail.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Jamali, Mohammad Khan, E-mail: mkhanjamali@yahoo.com [Government degree college Usta Mohammad Balochistan Pakistan (Pakistan)

    2009-08-15

    The purpose of this paper is to develop a database of fish tissues and to evaluate concentration of arsenic (As) in five tissues of fish species collected from Manchar Lake Pakistan and to compare concentration of As in fish tissues of same fish species collected from the Indus River, Pakistan. A sensitive and precise, hydride generation atomic absorption spectrometry (HG AAS) method is presented for the determination of total Arsenic (As). Microwave acid-assisted digestion (MAD) procedure based on the mixture HNO{sub 3}/H{sub 2}O{sub 2} was evaluated. The method was successfully validated against CRM DORM-2 (dogfish muscle). Quantitative As recovery in CRM (DORM-2) was obtained and no statistical differences were found at 95% level by applying the t-test. The limit of detection (LOD) and limit of quantitation (LOQ), for As were established as 0.022 and 0.063 {mu}g g{sup -1}, respectively. The results of this study indicated that As concentration in fish tissues from the Indus River are generally lower than in tissues of fishes from Manchar Lake. Arsenic concentrations in fish tissues of Indus River are although above the respective human health-based concentrations.

  11. Effects of metastability on hydrogen sorption in fluorine substituted hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Pinatel, E.R.; Corno, M.; Ugliengo, P.; Baricco, M., E-mail: marcello.baricco@unito.it

    2014-12-05

    Highlights: • Fluorine substitution in simple metal hydrides has been modelled. • The stability of the MH{sub (1−x)}F{sub x} solid solutions has been discussed. • Conditions for reversibility of sorption reactions have been suggested. - Abstract: In this work ab initio calculations and Calphad modelling have been coupled to describe the effect of fluorine substitution on the thermodynamics of hydrogenation–dehydrogenation in simple hydrides (NaH, AlH{sub 3} and CaH{sub 2}). These example systems have been used to discuss the conditions required for the formation of a stable hydride–fluoride solid solution necessary to obtain a reversible hydrogenation reaction.

  12. X-ray photoemission spectroscopy study of zirconium hydride

    International Nuclear Information System (INIS)

    X-ray photoemission spectroscopy (XPS) measurements are reported for ZrH/sub 1.65/ and Zr metal. The valence-band measurements are compared with available band-theory density-of-states calculations for the metal and hydride. The hydride spectrum differs significantly from the metal spectrum. Most important, a strong peak associated with hydrogen s electrons appears approximately 7 eV below the Fermi level. XPS measurements of Zr 4p core levels show a binding-energy shift of 1 eV between Zr metal and ZrH/sub 1.65/. It is argued that this shift results from charge readjustment in the vicinity of the Zr site. With the addition of hydrogen, net charge must be transferred from the Zr site to the hydrogen site. A charge-density analysis based on simplified cluster calculations is presented

  13. FEASIBILITY OF RECYCLING PLUTONIUM AND MINOR ACTINIDES IN LIGHT WATER REACTORS USING HYDRIDE FUEL

    International Nuclear Information System (INIS)

    The objective of this DOE NERI program sponsored project was to assess the feasibility of improving the plutonium (Pu) and minor actinide (MA) recycling capabilities of pressurized water reactors (PWRs) by using hydride instead of oxide fuels. There are four general parts to this assessment: (1) Identifying promising hydride fuel assembly designs for recycling Pu and MAs in PWRs; (2) Performing a comprehensive systems analysis that compares the fuel cycle characteristics of Pu and MA recycling in PWRs using the promising hydride fuel assembly designs identified in Part 1 versus using oxide fuel assembly designs; (3) Conducting a safety analysis to assess the likelihood of licensing hydride fuel assembly designs; and (4) Assessing the compatibility of hydride fuel with cladding materials and water under typical PWR operating conditions Hydride fuel was found to offer promising transmutation characteristics and is recommended for further examination as a possible preferred option for recycling plutonium in PWRs

  14. FEASIBILITY OF RECYCLING PLUTONIUM AND MINOR ACTINIDES IN LIGHT WATER REACTORS USING HYDRIDE FUEL

    Energy Technology Data Exchange (ETDEWEB)

    Greenspan, Ehud; Todreas, Neil; Taiwo, Temitope

    2009-03-10

    The objective of this DOE NERI program sponsored project was to assess the feasibility of improving the plutonium (Pu) and minor actinide (MA) recycling capabilities of pressurized water reactors (PWRs) by using hydride instead of oxide fuels. There are four general parts to this assessment: 1) Identifying promising hydride fuel assembly designs for recycling Pu and MAs in PWRs 2) Performing a comprehensive systems analysis that compares the fuel cycle characteristics of Pu and MA recycling in PWRs using the promising hydride fuel assembly designs identified in Part 1 versus using oxide fuel assembly designs 3) Conducting a safety analysis to assess the likelihood of licensing hydride fuel assembly designs 4) Assessing the compatibility of hydride fuel with cladding materials and water under typical PWR operating conditions Hydride fuel was found to offer promising transmutation characteristics and is recommended for further examination as a possible preferred option for recycling plutonium in PWRs.

  15. Arsenic groundwater contamination and its health effects in Patna district (capital of Bihar) in the middle Ganga plain, India.

    Science.gov (United States)

    Chakraborti, Dipankar; Rahman, Mohammad Mahmudur; Ahamed, Sad; Dutta, Rathindra Nath; Pati, Shyamapada; Mukherjee, Subhash Chandra

    2016-06-01

    We investigated the extent and severity of groundwater arsenic (As) contamination in five blocks in Patna district, Bihar, India along with As in biological samples and its health effects such as dermatological, neurological and obstetric outcome in some villages. We collected 1365 hand tube-well water samples and analyzed for As by the flow injection hydride generation atomic absorption spectrometer (FI-HG-AAS). We found 61% and 44% of the tube-wells had As above 10 and 50 μg/l, respectively, with maximum concentration of 1466 μg/l. Our medical team examined 712 villagers and registered 69 (9.7%) with arsenical skin lesions. Arsenical skin lesions were also observed in 9 children of 312 screened. We analyzed 176 biological samples (hair, nail and urine). Out of these, 69 people had arsenical skin lesions and rest without skin lesions. We found 100% of the biological samples had As above the normal levels (concentrations of As in hair, nail and urine of unexposed individuals usually ranges from 20 to 200 μg/kg, 20-500 μg/kg and situation in affected areas, villagers urgently need (a) provision of As-safe water for drinking and cooking, (b) awareness about the danger of As toxicity, and (c) nutritious food. PMID:27011321

  16. Effect of thermo-mechanical cycling on zirconium hydride reorientation studied in situ with synchrotron X-ray diffraction

    Science.gov (United States)

    Colas, Kimberly B.; Motta, Arthur T.; Daymond, Mark R.; Almer, Jonathan D.

    2013-09-01

    The circumferential hydrides normally present in nuclear reactor fuel cladding after reactor exposure may dissolve during drying for dry storage and re-precipitate when cooled under load into a more radial orientation, which could embrittle the fuel cladding. It is necessary to study the rates and conditions under which hydride reorientation may happen in order to assess fuel integrity in dry storage. The objective of this work is to study the effect of applied stress and thermal cycling on the hydride morphology in cold-worked stress-relieved Zircaloy-4 by combining conventional metallography and in situ X-ray diffraction techniques. Metallography is used to study the evolution of hydride morphology after several thermo-mechanical cycles. In situ X-ray diffraction performed at the Advanced Photon Source synchrotron provides real-time information on the process of hydride dissolution and precipitation under stress during several thermal cycles. The detailed study of diffracted intensity, peak position and full-width at half-maximum provides information on precipitation kinetics, elastic strains and other characteristics of the hydride precipitation process. The results show that thermo-mechanical cycling significantly increases the radial hydride fraction as well as the hydride length and connectivity. The radial hydrides are observed to precipitate at a lower temperature than circumferential hydrides. Variations in the magnitude and range of hydride strains due to reorientation and cycling have also been observed. These results are discussed in light of existing models and experiments on hydride reorientation. The study of hydride elastic strains during precipitation shows marked differences between circumferential and radial hydrides, which can be used to investigate the reorientation process. Cycling under stress above the threshold stress for reorientation drastically increases both the reoriented hydride fraction and the hydride size. The reoriented hydride

  17. Inelastic neutron scattering from amorphous hydride of Zr2Pd

    International Nuclear Information System (INIS)

    Time-of-flight inelastic neutron scattering data was obtained on hydrided Zr2Pd metallic glass using the Crystal Analyzer Spectrometer at the Los Alamos pulsed spallation neutron source. Energy transfers from about 40 MeV to several hundred MeV were obtained with sufficiently good statistics and signal to noise ratio to show the second harmonic as well as the fundamental hydrogen optic mode

  18. Proximity breakdown of hydrides in superconducting niobium cavities

    OpenAIRE

    Romanenko, A.; Barkov, F.; Cooley, L. D.; Grassellino, A.

    2012-01-01

    Many modern and proposed future particle accelerators rely on superconducting radio frequency cavities made of bulk niobium as primary particle accelerating structures. Such cavities suffer from the anomalous field dependence of their quality factors Q0. High field degradation - so-called high field Q-slope - is yet unexplained even though an empirical cure is known. Here we propose a mechanism based on the presence of proximity-coupled niobium hydrides, which can explain this effect. Further...

  19. METHOD OF MAKING DELTA ZIRCONIUM HYDRIDE MONOLITHIC MODERATOR PIECES

    Science.gov (United States)

    Vetrano, J.B.

    1962-01-23

    A method is given for preparing large, sound bodies of delta zirconium hydride. The method includes the steps of heating a zirconium body to a temperature of not less than l000 deg C, providing a hydrogen atmosphere for the zirconium body at a pressure not greater than one atmosphere, reducing the temperature slowly to 800 deg C at such a rate that cracks do not form while maintaining the hydrogen pressure substantially constant, and cooling in an atmosphere of hydrogen. (AEC)

  20. Hydrogen storage materials and metal hydride-Ni batteries

    International Nuclear Information System (INIS)

    The hydrogen storage alloy is the key active material in metal hydride-Ni (MH-Ni) batteries. A brief review of hydrogen storage negative electrode materials including misch-nickel-based alloys, Laves phase alloys, magnesium-based alloys, vanadium-based solid solutions and nanotubes is presented. Current problems that need to be solved are mentioned. In addition, recent developments of MH/Ni-batteries with high power and energy are introduced

  1. Discovery of the Arsenic Isotopes

    CERN Document Server

    Shore, A; Heim, M; Schuh, A; Thoennessen, M

    2009-01-01

    Twenty-nine arsenic isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  2. Oxidation of Group 8 transition-Metal Hydrides and Ionic Hydrogenation of Ketones and Aldehydes

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Kjell-Tore

    1996-08-01

    Transition-metal hydrides have received considerable attention during the last decades because of their unusual reactivity and their potential as homogeneous catalysts for hydrogenation and other reactions of organic substrates. An important class of catalytic processes where transition-metal hydrides are involved is the homogeneous hydrogenation of alkenes, alkynes, ketones, aldehydes, arenes and nitro compounds. This thesis studies the oxidation of Group 8 transition-metal hydrides and the ionic hydrogenation of ketones and aldehydes.

  3. Another Look at the Mechanisms of Hydride Transfer Enzymes with Quantum and Classical Transition Path Sampling

    OpenAIRE

    Dzierlenga, Michael W.; Antoniou, Dimitri; Schwartz, Steven D.

    2015-01-01

    The mechanisms involved in enzymatic hydride transfer have been studied for years, but questions remain due, in part, to the difficulty of probing the effects of protein motion and hydrogen tunneling. In this study, we use transition path sampling (TPS) with normal mode centroid molecular dynamics (CMD) to calculate the barrier to hydride transfer in yeast alcohol dehydrogenase (YADH) and human heart lactate dehydrogenase (LDH). Calculation of the work applied to the hydride allowed for obser...

  4. High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

    Directory of Open Access Journals (Sweden)

    Borislav Bogdanović

    2009-01-01

    Full Text Available For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

  5. High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

    OpenAIRE

    Borislav Bogdanović; Michael Felderhoff

    2009-01-01

    For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

  6. Synthesis of Renewable Energy Materials, Sodium Aluminum Hydride by Grignard Reagent of Al

    OpenAIRE

    Jun-qin Wang; Jian-feng Gao; Zhi-gang Wu; Guo-li Ou; Yu Wang

    2015-01-01

    The research on hydrogen generation and application has attracted widespread attention around the world. This paper is to demonstrate that sodium aluminum hydride can be synthesized under simple and mild reaction condition. Being activated through organics, aluminum powder reacts with hydrogen and sodium hydride to produce sodium aluminum hydride under atmospheric pressure. The properties and composition of the sample were characterized by FTIR, XRD, SEM, and so forth. The results showed that...

  7. Superconductivity of novel tin hydrides (SnnHm) under pressure

    Science.gov (United States)

    Mahdi Davari Esfahani, M.; Wang, Zhenhai; Oganov, Artem R.; Dong, Huafeng; Zhu, Qiang; Wang, Shengnan; Rakitin, Maksim S.; Zhou, Xiang-Feng

    2016-01-01

    With the motivation of discovering high-temperature superconductors, evolutionary algorithm USPEX is employed to search for all stable compounds in the Sn-H system. In addition to the traditional SnH4, new hydrides SnH8, SnH12 and SnH14 are found to be thermodynamically stable at high pressure. Dynamical stability and superconductivity of tin hydrides are systematically investigated. Im2-SnH8, C2/m-SnH12 and C2/m-SnH14 exhibit higher superconducting transition temperatures of 81, 93 and 97 K compared to the traditional compound SnH4 with Tc of 52 K at 200 GPa. An interesting bent H3–group in Im2-SnH8 and novel linear H in C2/m-SnH12 are observed. All the new tin hydrides remain metallic over their predicted range of stability. The intermediate-frequency wagging and bending vibrations have more contribution to electron-phonon coupling parameter than high-frequency stretching vibrations of H2 and H3. PMID:26964636

  8. Multidimensional Chemical Modeling. III. Abundance and excitation of diatomic hydrides

    CERN Document Server

    Bruderer, Simon; Stäuber, P; Doty, Steven D

    2010-01-01

    The Herschel Space Observatory opens the sky for observations in the far infrared at high spectral and spatial resolution. A particular class of molecules will be directly observable; light diatomic hydrides and their ions (CH, OH, SH, NH, CH+, OH+, SH+, NH+). These simple constituents are important both for the chemical evolution of the region and as tracers of high-energy radiation. If outflows of a forming star erode cavities in the envelope, protostellar far UV (FUV; 6 100 K) for water ice to evaporate. If the cavity shape allows FUV radiation to penetrate this hot-core region, the abundance of FUV destroyed species (e.g. water) is decreased. In particular, diatomic hydrides and their ions CH$+, OH+ and NH+ are enhanced by many orders of magnitude in the outflow walls due to the combination of high gas temperatures and rapid photodissociation of more saturated species. The enhancement of these diatomic hydrides is sufficient for a detection using the HIFI and PACS instruments onboard Herschel. The effect...

  9. Pressure-driven formation and stabilization of superconductive chromium hydrides

    Science.gov (United States)

    Yu, Shuyin; Jia, Xiaojing; Frapper, Gilles; Li, Duan; Oganov, Artem R.; Zeng, Qingfeng; Zhang, Litong

    2015-01-01

    Chromium hydride is a prototype stoichiometric transition metal hydride. The phase diagram of Cr-H system at high pressures remains largely unexplored due to the challenges in dealing with the high activation barriers and complications in handing hydrogen under pressure. We have performed an extensive structural study on Cr-H system at pressure range 0 ∼ 300 GPa using an unbiased structure prediction method based on evolutionary algorithm. Upon compression, a number of hydrides are predicted to become stable in the excess hydrogen environment and these have compositions of Cr2Hn (n = 2–4, 6, 8, 16). Cr2H3, CrH2 and Cr2H5 structures are versions of the perfect anti-NiAs-type CrH with ordered tetrahedral interstitial sites filled by H atoms. CrH3 and CrH4 exhibit host-guest structural characteristics. In CrH8, H2 units are also identified. Our study unravels that CrH is a superconductor at atmospheric pressure with an estimated transition temperature (T c) of 10.6 K, and superconductivity in CrH3 is enhanced by the metallic hydrogen sublattice with T c of 37.1 K at 81 GPa, very similar to the extensively studied MgB2. PMID:26626579

  10. Performance study of a hydrogen powered metal hydride actuator

    Science.gov (United States)

    Mainul Hossain Bhuiya, Md; Kim, Kwang J.

    2016-04-01

    A thermally driven hydrogen powered actuator integrating metal hydride hydrogen storage reactor, which is compact, noiseless, and able to generate smooth actuation, is presented in this article. To test the plausibility of a thermally driven actuator, a conventional piston type actuator was integrated with LaNi5 based hydrogen storage system. Copper encapsulation followed by compaction of particles into pellets, were adopted to improve overall thermal conductivity of the reactor. The operation of the actuator was thoroughly investigated for an array of operating temperature ranges. Temperature swing of the hydride reactor triggering smooth and noiseless actuation over several operating temperature ranges were monitored for quantification of actuator efficiency. Overall, the actuator generated smooth and consistent strokes during repeated cycles of operation. The efficiency of the actuator was found to be as high as 13.36% for operating a temperature range of 20 °C-50 °C. Stress-strain characteristics, actuation hysteresis etc were studied experimentally. Comparison of stress-strain characteristics of the proposed actuator with traditional actuators, artificial muscles and so on was made. The study suggests that design modification and use of high pressure hydride may enhance the performance and broaden the application horizon of the proposed actuator in future.

  11. Impact of exposure to tobacco smoke, arsenic, and phthalates on locally advanced cervical cancer treatment—preliminary results

    Science.gov (United States)

    Bloom, Michael S.; Dumitrascu, Irina; Roba, Carmen A.; Pop, Cristian; Ordeanu, Claudia; Balacescu, Ovidiu; Gurzau, Eugen S.

    2016-01-01

    Background Cancer research is a national and international priority, with the efficiency and effectiveness of current anti-tumor therapies being one of the major challenges with which physicians are faced. Objective To assess the impact of exposure to tobacco smoke, arsenic, and phthalates on cervical cancer treatment. Methods We investigated 37 patients with locally advanced cervical carcinoma who underwent chemotherapy and radiotherapy. We determined cotinine and five phthalate metabolites in urine samples collected prior to cancer treatment, by gas chromatography coupled to mass spectrometry, and urinary total arsenic by atomic absorption spectrometry with hydride generation. We used linear regression to evaluate the effects of cotinine, arsenic, and phthalates on the change in tumor size after treatment, adjusted for confounding variables. Results We detected no significant associations between urinary cotinine, arsenic, or phthalate monoesters on change in tumor size after treatment, adjusted for urine creatinine, age, baseline tumor size, and cotinine (for arsenic and phthalates). However, higher %mono-ethylhexyl phthalate (%MEHP), a putative indicator of phthalate diester metabolism, was associated with a larger change in tumor size (β = 0.015, 95% CI [0.003–0.03], P = 0.019). Conclusion We found no statistically significant association between the urinary levels of arsenic, cotinine, and phthalates metabolites and the response to cervical cancer treatment as measured by the change in tumor size. Still, our results suggested that phthalates metabolism may be associated with response to treatment for locally advanced cervical cancer. However, these observations are preliminary and will require confirmation in a larger, more definitive investigation. PMID:27652000

  12. Effect of the hydrogen content and cooling velocity in the hydrides precipitation in α-zirconium

    International Nuclear Information System (INIS)

    Zirconium specimens containing 50-300 ppm hydrogen have been cooled from the hydrogen solution treatment temperature at different rates by furnace cooling, air cooling and oil quenching. Optical and electron microscopical investigations have revealed grain boundary Δ - hydrides in slowly cooled specimens. At higher cooling rates γ and Δ hydrides have been found precipitated both intergranularly and intragranularly. Grain boundary Δ hydrides have been also observed in oil quenched specimens with 300 ppm hydrogen. Quenched specimens have revealed Widmanstatten and parallel plate type hydride morphologies. (Author)

  13. Synthesis of Renewable Energy Materials, Sodium Aluminum Hydride by Grignard Reagent of Al

    Directory of Open Access Journals (Sweden)

    Jun-qin Wang

    2015-01-01

    Full Text Available The research on hydrogen generation and application has attracted widespread attention around the world. This paper is to demonstrate that sodium aluminum hydride can be synthesized under simple and mild reaction condition. Being activated through organics, aluminum powder reacts with hydrogen and sodium hydride to produce sodium aluminum hydride under atmospheric pressure. The properties and composition of the sample were characterized by FTIR, XRD, SEM, and so forth. The results showed that the product through this synthesis method is sodium aluminum hydride, and it has higher purity, perfect crystal character, better stability, and good hydrogen storage property. The reaction mechanism is also discussed in detail.

  14. Arsenic removal by lime softening

    DEFF Research Database (Denmark)

    Kaosol, T.; Suksaroj, C.; Bregnhøj, Henrik

    2002-01-01

    This paper focuses on the study of arsenic removal for drinking water by lime softening. The initial arsenic (V) concentration was 500 and 1,000 ug/L in synthetic groundwater. The experiments were performed as batch tests with varying lime dosages and mixing time. For the synthetic groundwater......, arsenic (V) removal increased with increasing lime dosage and mixing time, as well as with the resulting pH. The residual arsenic (V) in all cases was lower than the WHO guideline of 10 ug/L at pH higher than 11.5. Kinetic of arsenic (V) removal can be described by a first-order equation as C1 = C0*e......^-k*t. The relation between the constant (k value) and increasing lime dosage was found to be linear, described by k = 0.0034 (Dlime). The results support a theory from the literature that the arsenic (V) was removed by precipitation af Ca3(AsO4)2. The results obtained in the present study suggest that lime...

  15. Arsenic-resistant bacteria solubilized arsenic in the growth media and increased growth of arsenic hyperaccumulator Pteris vittata L.

    Science.gov (United States)

    Ghosh, Piyasa; Rathinasabapathi, Bala; Ma, Lena Q

    2011-10-01

    The role of arsenic-resistant bacteria (ARB) in arsenic solubilization from growth media and growth enhancement of arsenic-hyperaccumulator Pteris vittata L. was examined. Seven ARB (tolerant to 10 mM arsenate) were isolated from the P. vittata rhizosphere and identified by 16S rRNA sequencing as Pseudomonas sp., Comamonas sp. and Stenotrophomonas sp. During 7-d hydroponic experiments, these bacteria effectively solubilized arsenic from the growth media spiked with insoluble FeAsO₄ and AlAsO₄ minerals (from organic C) by P. vittata may be responsible for As solubilization. Increase in P. vittata root biomass from 1.5-2.2 to 3.4-4.2 g/plant dw by ARB and by arsenic was associated with arsenic-induced plant P uptake. Arsenic resistant bacteria may have potential to enhance phytoremediation of arsenic-contaminated soils by P. vittata. PMID:21840210

  16. Approaches to Increase Arsenic Awareness in Bangladesh: An Evaluation of an Arsenic Education Program

    Science.gov (United States)

    George, Christine Marie; Factor-Litvak, Pam; Khan, Khalid; Islam, Tariqul; Singha, Ashit; Moon-Howard, Joyce; van Geen, Alexander; Graziano, Joseph H.

    2013-01-01

    The objective of this study was to design and evaluate a household-level arsenic education and well water arsenic testing intervention to increase arsenic awareness in Bangladesh. The authors randomly selected 1,000 study respondents located in 20 villages in Singair, Bangladesh. The main outcome was the change in knowledge of arsenic from…

  17. Reactivity patterns of transition metal hydrides and alkyls

    Energy Technology Data Exchange (ETDEWEB)

    Jones, W.D. II

    1979-05-01

    The complex PPN/sup +/ CpV(CO)/sub 3/H/sup -/ (Cp=eta/sup 5/-C/sub 5/H/sub 5/ and PPN = (Ph/sub 3/P)/sub 2/) was prepared in 70% yield and its physical properties and chemical reactions investigated. PPN/sup +/ CpV(CO)/sub 3/H/sup -/ reacts with a wide range of organic halides. The organometallic products of these reactions are the vanadium halides PPN/sup +/(CpV(C)/sub 3/X)/sup -/ and in some cases the binuclear bridging hydride PPN/sup +/ (CpV(CO)/sub 3/)/sub 2/H/sup -/. The borohydride salt PPN/sup +/(CpV(CO)/sub 3/BH/sub 4/)/sup -/ has also been prepared. The reaction between CpV(CO)/sub 3/H/sup -/ and organic halides was investigated and compared with halide reductions carried out using tri-n-butyltin hydride. Results demonstrate that in almost all cases, the reduction reaction proceeds via free radical intermediates which are generated in a chain process, and are trapped by hydrogen transfer from CpV(CO)/sub 3/H/sup -/. Sodium amalgam reduction of CpRh(CO)/sub 2/ or a mixture of CpRh(CO)/sub 2/ and CpCo(CO)/sub 2/ affords two new anions, PPN/sup +/ (Cp/sub 2/Rh/sub 3/(CO)/sub 4/)/sup -/ and PPN/sup +/(Cp/sub 2/RhCo(CO)/sub 2/)/sup -/. CpMo(CO)/sub 3/H reacts with CpMo(CO)/sub 3/R (R=CH/sub 3/,C/sub 2/H/sub 5/, CH/sub 2/C/sub 6/H/sub 5/) at 25 to 50/sup 0/C to produce aldehyde RCHO and the dimers (CpMo(CO)/sub 3/)/sub 2/ and (CpMo(CO)/sub 2/)/sub 2/. In general, CpV(CO)/sub 3/H/sup -/ appears to transfer a hydrogen atom to the metal radical anion formed in an electron transfer process, whereas CpMo(CO)/sub 3/H transfers hydride in a 2-electron process to a vacant coordination site. The chemical consequences are that CpV(CO)/sub 3/H/sup -/ generally reacts with metal alkyls to give alkanes via intermediate alkyl hydride species whereas CpMo(CO)/sub 3/H reacts with metal alkyls to produce aldehyde, via an intermediate acyl hydride species.

  18. Reactivity patterns of transition metal hydrides and alkyls

    International Nuclear Information System (INIS)

    The complex PPN+ CpV(CO)3H- (Cp=eta5-C5H5 and PPN = (Ph3P)2) was prepared in 70% yield and its physical properties and chemical reactions investigated. PPN+ CpV(CO)3H- reacts with a wide range of organic halides. The organometallic products of these reactions are the vanadium halides PPN+[CpV(C)3X]- and in some cases the binuclear bridging hydride PPN+ [CpV(CO)3]2H-. The borohydride salt PPN+[CpV(CO)3BH4]- has also been prepared. The reaction between CpV(CO)3H- and organic halides was investigated and compared with halide reductions carried out using tri-n-butyltin hydride. Results demonstrate that in almost all cases, the reduction reaction proceeds via free radical intermediates which are generated in a chain process, and are trapped by hydrogen transfer from CpV(CO)3H-. Sodium amalgam reduction of CpRh(CO)2 or a mixture of CpRh(CO)2 and CpCo(CO)2 affords two new anions, PPN+ [Cp2Rh3(CO)4]- and PPN+[Cp2RhCo(CO)2]-. CpMo(CO)3H reacts with CpMo(CO)3R (R=CH3,C2H5, CH2C6H5) at 25 to 500C to produce aldehyde RCHO and the dimers [CpMo(CO)3]2 and [CpMo(CO)2]2. In general, CpV(CO)3H- appears to transfer a hydrogen atom to the metal radical anion formed in an electron transfer process, whereas CpMo(CO)3H transfers hydride in a 2-electron process to a vacant coordination site. The chemical consequences are that CpV(CO)3H- generally reacts with metal alkyls to give alkanes via intermediate alkyl hydride species whereas CpMo(CO)3H reacts with metal alkyls to produce aldehyde, via an intermediate acyl hydride species

  19. Effect of organic matter amendment, arsenic amendment and water management regime on rice grain arsenic species.

    Science.gov (United States)

    Norton, Gareth J; Adomako, Eureka E; Deacon, Claire M; Carey, Anne-Marie; Price, Adam H; Meharg, Andrew A

    2013-06-01

    Arsenic accumulation in rice grain has been identified as a major problem in some regions of Asia. A study was conducted to investigate the effect of increased organic matter in the soil on the release of arsenic into soil pore water and accumulation of arsenic species within rice grain. It was observed that high concentrations of soil arsenic and organic matter caused a reduction in plant growth and delayed flowering time. Total grain arsenic accumulation was higher in the plants grown in high soil arsenic in combination with high organic matter, with an increase in the percentage of organic arsenic species observed. The results indicate that the application of organic matter should be done with caution in paddy soils which have high soil arsenic, as this may lead to an increase in accumulation of arsenic within rice grains. Results also confirm that flooding conditions substantially increase grain arsenic.

  20. XRCC1 Arg194Trp and Arg399Gln polymorphisms and arsenic methylation capacity are associated with urothelial carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Chien-I [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Huang, Ya-Li [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Chen, Wei-Jen [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (China); Huang, Chao-Yuan; Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, College of Medicine National Taiwan University, Taipei, Taiwan (China); Lin, Ying-Chin [Department of Family Medicine, Shung Ho Hospital, Taipei Medical University, New Taipei, Taiwan (China); Department of Health Examination, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan (China); Division of Family Medicine, School of Medicine, Taipei Medical University, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2014-09-15

    The association between DNA repair gene polymorphisms and bladder cancer has been widely studied. However, few studies have examined the correlation between urothelial carcinoma (UC) and arsenic or its metabolites. The aim of this study was to examine the association between polymorphisms of the DNA repair genes, XRCC1 Arg194Trp, XRCC1 Arg399Gln, XRCC3 Thr241Met, and XPD Lys751Gln, with urinary arsenic profiles and UC. To this end, we conducted a hospital-based case–control study with 324 UC patients and 647 age- and gender-matched non-cancer controls. Genomic DNA was used to examine the genotype of XRCC1 Arg194Trp, XRCC1 Arg399Gln, XRCC3 Thr241Met, and XPD Lys751Gln by PCR-restriction fragment length polymorphism analysis (PCR-RFLP). Urinary arsenic profiles were measured by high performance liquid chromatography (HPLC) linked with hydride generator and atomic absorption spectrometry. The XRCC1 399 Gln/Gln and 194 Arg/Trp and Trp/Trp genotypes were significantly related to UC, and the odds ratio (OR) and 95% confidence interval (95%CI) were 1.68 (1.03–2.75) and 0.66 (0.48–0.90), respectively. Participants with higher total urinary arsenic levels, a higher percentage of inorganic arsenic (InAs%) and a lower percentage of dimethylarsinic acid (DMA%) had a higher OR of UC. Participants carrying XRCC1 risk diplotypes G-C/G-C, A-C/A-C, and A-T/G-T, and who had higher total arsenic levels, higher InAs%, or lower DMA% compared to those with other XRCC1 diplotypes had a higher OR of UC. Our results suggest that the XRCC1 399 Gln/Gln and 194 Arg/Arg DNA repair genes play an important role in poor arsenic methylation capacity, thereby increasing the risk of UC in non-obvious arsenic exposure areas. - Highlights: • The XRCC1 399Gln/Gln genotype was significantly associated with increased OR of UC. • The XRCC1 194 Arg/Trp and Trp/Trp genotype had a significantly decreased OR of UC. • Combined effect of the XRCC1 genotypes and poor arsenic methylation capacity on

  1. Exposure to Inorganic Arsenic Is Associated with Increased Mitochondrial DNA Copy Number and Longer Telomere Length in Peripheral Blood

    Science.gov (United States)

    Ameer, Syeda S.; Xu, YiYi; Engström, Karin; Li, Huiqi; Tallving, Pia; Nermell, Barbro; Boemo, Analia; Parada, Luis A.; Peñaloza, Lidia G.; Concha, Gabriela; Harari, Florencia; Vahter, Marie; Broberg, Karin

    2016-01-01

    Background: Exposure to inorganic arsenic (iAs) through drinking water causes cancer. Alterations in mitochondrial DNA copy number (mtDNAcn) and telomere length in blood have been associated with cancer risk. We elucidated if arsenic exposure alters mtDNAcn and telomere length in individuals with different arsenic metabolizing capacity. Methods: We studied two groups in the Salta province, Argentina, one in the Puna area of the Andes (N = 264, 89% females) and one in Chaco (N = 169, 75% females). We assessed arsenic exposure as the sum of arsenic metabolites [iAs, methylarsonic acid (MMA), dimethylarsinic acid (DMA)] in urine (U-As) using high-performance liquid chromatography coupled with hydride generation and inductively coupled plasma mass spectrometry. Efficiency of arsenic metabolism was expressed as percentage of urinary metabolites. MtDNAcn and telomere length were determined in blood by real-time PCR. Results: Median U-As was 196 (5–95 percentile: 21–537) μg/L in Andes and 80 (5–95 percentile: 15–1637) μg/L in Chaco. The latter study group had less-efficient metabolism, with higher %iAs and %MMA in urine compared with the Andean group. U-As was significantly associated with increased mtDNAcn (log2 transformed to improve linearity) in Chaco (β = 0.027 per 100 μg/L, p = 0.0085; adjusted for age and sex), but not in Andes (β = 0.025, p = 0.24). U-As was also associated with longer telomere length in Chaco (β = 0.016, p = 0.0066) and Andes (β = 0.0075, p = 0.029). In both populations, individuals with above median %iAs showed significantly higher mtDNAcn and telomere length compared with individuals with below median %iAs. Conclusions: Arsenic was associated with increased mtDNAcn and telomere length, particularly in individuals with less-efficient arsenic metabolism, a group who may have increased risk for arsenic-related cancer. PMID:27597942

  2. XRCC1 Arg194Trp and Arg399Gln polymorphisms and arsenic methylation capacity are associated with urothelial carcinoma

    International Nuclear Information System (INIS)

    The association between DNA repair gene polymorphisms and bladder cancer has been widely studied. However, few studies have examined the correlation between urothelial carcinoma (UC) and arsenic or its metabolites. The aim of this study was to examine the association between polymorphisms of the DNA repair genes, XRCC1 Arg194Trp, XRCC1 Arg399Gln, XRCC3 Thr241Met, and XPD Lys751Gln, with urinary arsenic profiles and UC. To this end, we conducted a hospital-based case–control study with 324 UC patients and 647 age- and gender-matched non-cancer controls. Genomic DNA was used to examine the genotype of XRCC1 Arg194Trp, XRCC1 Arg399Gln, XRCC3 Thr241Met, and XPD Lys751Gln by PCR-restriction fragment length polymorphism analysis (PCR-RFLP). Urinary arsenic profiles were measured by high performance liquid chromatography (HPLC) linked with hydride generator and atomic absorption spectrometry. The XRCC1 399 Gln/Gln and 194 Arg/Trp and Trp/Trp genotypes were significantly related to UC, and the odds ratio (OR) and 95% confidence interval (95%CI) were 1.68 (1.03–2.75) and 0.66 (0.48–0.90), respectively. Participants with higher total urinary arsenic levels, a higher percentage of inorganic arsenic (InAs%) and a lower percentage of dimethylarsinic acid (DMA%) had a higher OR of UC. Participants carrying XRCC1 risk diplotypes G-C/G-C, A-C/A-C, and A-T/G-T, and who had higher total arsenic levels, higher InAs%, or lower DMA% compared to those with other XRCC1 diplotypes had a higher OR of UC. Our results suggest that the XRCC1 399 Gln/Gln and 194 Arg/Arg DNA repair genes play an important role in poor arsenic methylation capacity, thereby increasing the risk of UC in non-obvious arsenic exposure areas. - Highlights: • The XRCC1 399Gln/Gln genotype was significantly associated with increased OR of UC. • The XRCC1 194 Arg/Trp and Trp/Trp genotype had a significantly decreased OR of UC. • Combined effect of the XRCC1 genotypes and poor arsenic methylation capacity on

  3. Phytoextraction by arsenic hyperaccumulator Pteris vittata L. from six arsenic-contaminated soils: Repeated harvests and arsenic redistribution

    Energy Technology Data Exchange (ETDEWEB)

    Gonzaga, Maria I.S.; Santos, Jorge A.G. [Department of Soil Chemistry, Universidade Federal da Bahia, Cruz das Almas, 44380000 (Brazil); Ma, Lena Q. [Soil and Water Science Department, University of Florida, 2169 McCarty Hall, Gainesville, FL 32611-0290 (United States)], E-mail: lqma@ifas.ufl.edu

    2008-07-15

    This greenhouse experiment evaluated arsenic removal by Pteris vittata and its effects on arsenic redistribution in soils. P. vittata grew in six arsenic-contaminated soils and its fronds were harvested and analyzed for arsenic in October, 2003, April, 2004, and October, 2004. The soil arsenic was separated into five fractions via sequential extraction. The ferns grew well and took up arsenic from all soils. Fern biomass ranged from 24.8 to 33.5 g plant{sup -1} after 4 months of growth but was reduced in the subsequent harvests. The frond arsenic concentrations ranged from 66 to 6,151 mg kg{sup -1}, 110 to 3,056 mg kg{sup -1}, and 162 to 2,139 mg kg{sup -1} from the first, second and third harvest, respectively. P. vittata reduced soil arsenic by 6.4-13% after three harvests. Arsenic in the soils was primarily associated with amorphous hydrous oxides (40-59%), which contributed the most to arsenic taken up by P. vittata (45-72%). It is possible to use P. vittata to remediate arsenic-contaminated soils by repeatedly harvesting its fronds. - Pteris vittata was effective in continuously removing arsenic from contaminated soils after three repeated harvests.

  4. RARE CASE REPORT OF CHRONIC ARSENIC POISONING

    OpenAIRE

    Mundle; Neelima; Sushrut; Yogesh; Shukan; Shalik; Siddharth

    2014-01-01

    Today, arsenic is primarily used in the produc tion of glass and semiconductors., Arsenic may be found as a water or food contaminant, particularly in shellfish and other seafood, and often contaminates fruits and vegetables, particularly rice

  5. Inorganic arsenic poisoning in pastured feeder lambs

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, H.A.; Crane, M.R.; Tomson, K.

    1971-01-01

    Clinical signs and necropsy findings in a group of feeder lambs were suggestive of inorganic arsenic poisoning. Source of exposure was established and toxic concentrations of arsenic were detected in the tissues. 13 references, 1 table.

  6. Airborne exposure and estimated bioavailability of arsenic

    Energy Technology Data Exchange (ETDEWEB)

    Yager, J.W. [Electric Power Research Inst., Madison, WI (United States); Clewell, H.J. III [ICF Consulting, Fairfax, VA (United States); Hicks, J. [Geomatrix, (United States)

    2000-07-01

    A pilot group of workers were used in a study to determine the relationship between exposure to arsenic present in fly ash particles and urinary excretion of inorganic arsenic and its methylated metabolites. Arsenic was measured in the breathing zone of workers during full shift work schedules and daily urine samples were collected to determine the concentration of arsenic and its metabolites. Airborne particle size distribution samples were collected on six-stage personal cascade impactors. Previous studies of airborne exposure to arsenic in copper smelters predict urinary values nearly three times higher than those seen in exposure to arsenic in fly ash. The results suggest that differences in biological uptake of airborne arsenic probably depend on characteristics such as solubility, particle size and distribution and matrix composition of the arsenic compounds.

  7. Arsenic in the aetiology of cancer.

    Science.gov (United States)

    Tapio, Soile; Grosche, Bernd

    2006-06-01

    Arsenic, one of the most significant hazards in the environment affecting millions of people around the world, is associated with several diseases including cancers of skin, lung, urinary bladder, kidney and liver. Groundwater contamination by arsenic is the main route of exposure. Inhalation of airborne arsenic or arsenic-contaminated dust is a common health problem in many ore mines. This review deals with the questions raised in the epidemiological studies such as the dose-response relationship, putative confounders and synergistic effects, and methods evaluating arsenic exposure. Furthermore, it describes the metabolic pathways of arsenic, and its biological modes of action. The role of arsenic in the development of cancer is elucidated in the context of combined epidemiological and biological studies. However, further analyses by means of molecular epidemiology are needed to improve the understanding of cancer aetiology induced by arsenic.

  8. RARE CASE REPORT OF CHRONIC ARSENIC POISONING

    Directory of Open Access Journals (Sweden)

    Mundle

    2014-12-01

    Full Text Available Today, arsenic is primarily used in the produc tion of glass and semiconductors., Arsenic may be found as a water or food contaminant, particularly in shellfish and other seafood, and often contaminates fruits and vegetables, particularly rice

  9. Urinary Arsenic Metabolites in Children and Adults Exposed to Arsenic in Drinking Water in Inner Mongolia, China

    Science.gov (United States)

    Sun, Guifan; Xu, Yuanyuan; Li, Xin; Jin, Yaping; Li, Bing; Sun, Xiance

    2007-01-01

    Background We report the concentrations and distributions of urinary arsenic (As) metabolites in 233 residents exposed to 20, 90, or 160 μg/L inorganic arsenic (iAs) in drinking water from three villages in Hohhot, Inner Mongolia, China, that formed one control and two exposed groups. Methods We used hydride generation-atomic absorption spectrometry (HGAAS) to determine iAs, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA). Results The concentrations of each urinary As species in the two exposed groups were significantly higher than in the control group for both children and adults. Both children and adults in exposed groups had higher percent iAs and MMA and lower percent DMA, and low primary and secondary methylation indices (PMI and SMI, respectively) than those in the control group. However, children showed significant increases in percent DMA and the SMI as well as decreases in the percent MMA when the iAs exposure level increased from 90 to 160 μg/L. In addition, children in the two exposed groups showed lower percent MMA but higher percent DMA and higher SMI than adults in the same exposed group. No significant differences in As metabolite concentrations and distributions were found between males and females in each group. A significant correlation was also found in the SMI between 11 pairs of children and their mothers from the 160-μg/L–exposed group. Conclusions Children had higher a capacity for secondary methylation of As than adults when exposed to the same concentrations of iAs in drinking water. Exposure to As may increase the capacity for methylation in children to some extent. PMID:17450238

  10. Arsenic in contaminated soil and river sediment

    Energy Technology Data Exchange (ETDEWEB)

    Bombach, G. (Freiberg Univ. of Mining and Technology, Inst. of Mineralogy, Geochemistry and Ore Deposits, Freiberg (Germany)); Pierra, A. (Freiberg Univ. of Mining and Technology, Inst. of Mineralogy, Geochemistry and Ore Deposits, Freiberg (Germany)); Klemm, W. (Freiberg Univ. of Mining and Technology, Inst. of Mineralogy, Geochemistry and Ore Deposits, Freiberg (Germany))

    1994-09-01

    Different areas in the Erzgebirge mountains are contaminated by high arsenic concentration which is caused by the occurrence of ore and industrial sources. The study showed clearly a high concentration of arsenic in the surface and under soil (A and B horizons) in the Freiberg district. The distribution of the arsenic concentration in the area, the content of water soluble arsenic, the several oxidation states (As[sup 3+], As[sup 5+]) and the bonding types have been analyzed. (orig.)

  11. Urine arsenic methylated metabolism in mice exposed to acute arsenic%急性砷暴露小鼠尿砷甲基化代谢的研究

    Institute of Scientific and Technical Information of China (English)

    董丹丹; 王欣; 赵朔; 段晓旭; 李炜; 李冰

    2013-01-01

    Objective To investigate the level of urine arsenic excretion and methylated metabolism pattern in mice exposed to acute arsenic. Methods Healthy female Kunming mice were exposed to sodium arsenite ( NaAsO2) by intragastric infusion at doses of 2.5 mg/kg, 5.0 mg/kg, 10.0 mg/kg and 20.0 mg/kg, the exposure time for each group were 12 hours, 24 hours, 48 hours and 72 hours. The mice were placed in metabolic cages and urine samples of 24 - hour group were collected (urine samples of 12 hours were collect from 12 - hour group) before the end of exposure day. The level of inorganic arsenic (iAs) , monomethy-lated arsenic [ MMA) and dimethylated arsenic ( DMA) in urine were determined by cold trap hydride generation atomic absorption spectrophotometer respectively, the level of T-As, iAs% , MMA% , DMA% , primary methylation index (PMI) and secondary methylation index ( SMI) were calculated. Results Urine T - As level, iAs% and MMA in the mice exposed to acute arsenic increased significantly with the increase of arsenic concentration, but DMA% and SMI decreased with stable PMI. With the increase of time after exposure, urine T - As level, iAs% and MMA% gradually decreased, while DMA% , PMI and SMI increased significantly. The most urine arsenic were excreted within 24 hours, and its percentage content and methylation index were at same level, the level of urine arsenic excretion was very low in 48 - hour and 72 hour groups and their percentage content and methylation index were at same level. Conclusion Urine arsenic excretion in mice exposed to acute arsenic has obvious dose deffect relation and time - effect relation; High concentration of arsenic exposure may effectively inhibit methylated metabolism , and urine arsenic content within 24 hours could be used as an indicator to determine the arsenic burden of an acute arsenic poisoned body.%目的 探讨急性砷暴露小鼠尿砷排泄及其甲基化代谢模式.方法 健康雌性昆明种小鼠一次性灌

  12. Determination of fracture strength of δ-zirconium hydrides embedded in zirconium matrix at high temperatures

    Science.gov (United States)

    Kubo, T.; Kobayashi, Y.; Uchikoshi, H.

    2013-04-01

    The fracture strength of δ-zirconium hydrides embedded in a zirconium matrix was determined at temperatures between 25 °C and 250 °C by ring tensile tests using Zircaloy-2 tubes. Essentially all of the present hydrides in the tubes were re-oriented in the radial direction by a temperature cycling treatment and then tensile stress was applied perpendicular to the hydrides to ensure that brittle fracture would occur at the hydrides. The hydrides failed in a brittle manner below 100 °C where-as the zirconium matrix itself underwent ductile fracture without hydride cracking at temperatures above 200 °C under plane stress condition. Brittle fracture of the hydrides continued to occur at temperatures up to 250 °C under plane strain condition, suggesting that the upper limit temperature for hydride fracture, Tupper, was raised by the triaxial stress state under the plane strain condition. The apparent fracture strength of the hydrides, σhydridef, was determined at temperatures below Tupper from the measured fracture strength of the tubes, making a correction for the compressive transformation stress in the hydrides. σhydridef was about 710 MPa at temperatures between 25 °C and 250 °C at both plane stress and plane strain conditions. The temperature dependency was very small in this temperature range. Tupper was almost equivalent to the cross-over temperature between σhydridef and the ultimate tensile strength (UTS), which suggests that, at temperatures above Tupper, the zirconium matrix would undergo ductile fracture before the stress in the hydride is raised above σhydridef, since UTS is smaller than σhydridef.

  13. Arsenic - Multiple Languages: MedlinePlus

    Science.gov (United States)

    ... Are Here: Home → Multiple Languages → All Health Topics → Arsenic URL of this page: https://medlineplus.gov/languages/arsenic.html Other topics A-Z A B C ... V W XYZ List of All Topics All Arsenic - Multiple Languages To use the sharing features on ...

  14. 21 CFR 556.60 - Arsenic.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Arsenic. 556.60 Section 556.60 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND... New Animal Drugs § 556.60 Arsenic. Tolerances for total residues of combined arsenic (calculated as...

  15. 29 CFR 1910.1018 - Inorganic arsenic.

    Science.gov (United States)

    2010-07-01

    ... container in the change-room which prevents dispersion of inorganic arsenic outside the container. (vi) The... readily through the skin. Because inorganic arsenic is a poison, you should wash your hands thoroughly... 29 Labor 6 2010-07-01 2010-07-01 false Inorganic arsenic. 1910.1018 Section 1910.1018...

  16. Chloride sublimation of gold-arsenic concentrates

    International Nuclear Information System (INIS)

    Present article is devoted to chloride sublimation of gold-arsenic concentrates. The results of studies of chloride sublimation of gold-arsenic comprising concentrates of Chore deposit of Tajikistan are considered. It is found that by application sodium chloride for gold-arsenic comprising concentrates it is possible to extract gold and silver from flotation concentrates.

  17. Arsenic intoxication associated with tubulointerstitial nephritis.

    Science.gov (United States)

    Prasad, G V; Rossi, N F

    1995-08-01

    Arsenic poisoning is an often unrecognized cause of renal insufficiency. We report a case of tubulointerstitial nephritis associated with an elevated urinary arsenic concentration. Removal of the putative source of arsenic resulted in symptomatic improvement, resolution of abnormal abdominal radiographs, and stabilization of renal function. This case emphasizes the importance of heavy metal screening in patients with multisystem complaints and tubulointerstitial nephritis.

  18. The effect of cigarette smoke and arsenic exposure on urothelial carcinoma risk is modified by glutathione S-transferase M1 gene null genotype

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chi-Jung [Department of Health Risk Management, College of Public Health, China Medical University, Taichung, Taiwan (China); Department of Medical Research, China Medical University Hospital, Taichung, Taiwan (China); Huang, Chao-Yuan; Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan (China); Su, Chien-Tien [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China)

    2013-01-15

    Inter-individual variation in the metabolism of xenobiotics, caused by factors such as cigarette smoking or inorganic arsenic exposure, is hypothesized to be a susceptibility factor for urothelial carcinoma (UC). Therefore, our study aimed to evaluate the role of gene–environment interaction in the carcinogenesis of UC. A hospital-based case–control study was conducted. Urinary arsenic profiles were measured using high-performance liquid chromatography–hydride generator-atomic absorption spectrometry. Genotyping was performed using a polymerase chain reaction-restriction fragment length polymorphism technique. Information about cigarette smoking exposure was acquired from a lifestyle questionnaire. Multivariate logistic regression was applied to estimate the UC risk associated with certain risk factors. We found that UC patients had higher urinary levels of total arsenic, higher percentages of inorganic arsenic (InAs%) and monomethylarsonic acid (MMA%) and lower percentages of dimethylarsinic acid (DMA%) compared to controls. Subjects carrying the GSTM1 null genotype had significantly increased UC risk. However, no association was observed between gene polymorphisms of CYP1A1, EPHX1, SULT1A1 and GSTT1 and UC risk after adjustment for age and sex. Significant gene–environment interactions among urinary arsenic profile, cigarette smoking, and GSTM1 wild/null polymorphism and UC risk were observed after adjustment for potential risk factors. Overall, gene–environment interactions simultaneously played an important role in UC carcinogenesis. In the future, large-scale studies should be conducted using tag-SNPs of xenobiotic-metabolism-related enzymes for gene determination. -- Highlights: ► Subjects with GSTM1 null genotype had significantly increased UC risk. ► UC patients had poor arsenic metabolic ability compared to controls. ► GSTM1 null genotype may modify arsenic related UC risk.

  19. Urinary arsenic profiles and the risks of cancer mortality: A population-based 20-year follow-up study in arseniasis-endemic areas in Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chi-Jung [Department of Health Risk Management, College of Public Health, China Medical University, Taichung, Taiwan (China); Department of Medical Research, China Medical Hospital, Taichung, Taiwan (China); Huang, Ya-Li [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Huang, Yung-Kai [School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan (China); Wu, Meei-Maan [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Chen, Shu-Yuan [Department of Public Health, Tzu-Chi University, Hualien, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Chen, Chien-Jen [Genomics Research Center, Academia Sinica, Taipei, Taiwan (China)

    2013-04-15

    Few studies investigated the association between chronic arsenic exposure and the mortality of cancers by estimating individual urinary arsenic methylation profiles. Therefore, we compared with the general population in Taiwan to calculate the standardized mortality ratio (SMR) in arseniasis-endemic area of Taiwan from 1996 to 2010 and evaluated the dose-response relationships between environmental arsenic exposure indices or urinary arsenic profiles and the mortality of cause-specific cancer. A cohort of 1563 residents was conducted and collected their urine sample and information regarding arsenic exposure from a questionnaire. All-cause death was identified using the National Death Registry of Taiwan. Urinary arsenic profiles were measured using high performance liquid chromatography–hydride generator–atomic absorption spectrometry. We used Cox proportional hazard models to evaluate the mortality risks. In results, 193 all-site cancer deaths, and 29, 71, 43 deaths respectively for liver, lung and bladder cancers were ascertained. The SMRs were significantly high in arseniasis-endemic areas for liver, lung, and bladder cancers. People with high urinary InAs% or low DMA% or low secondary methylation index (SMI) were the most likely to suffer bladder cancer after adjusting other risk factors. Even stopping exposure to arsenic from the artesian well water, the mortality rates of the residents were higher than general population. Finally, urinary InAs%, DMA% and SMI could be the potential biomarkers to predict the mortality risk of bladder cancer. -- Highlights: ► The SMRs were significantly high in arseniasis-endemic areas for liver, lung, and bladder cancers. ► People with high urinary InAs% were the most likely to suffer bladder cancer. ► People with low DMA% or low SMI were the most likely to suffer bladder cancer.

  20. Urinary arsenic profiles and the risks of cancer mortality: A population-based 20-year follow-up study in arseniasis-endemic areas in Taiwan

    International Nuclear Information System (INIS)

    Few studies investigated the association between chronic arsenic exposure and the mortality of cancers by estimating individual urinary arsenic methylation profiles. Therefore, we compared with the general population in Taiwan to calculate the standardized mortality ratio (SMR) in arseniasis-endemic area of Taiwan from 1996 to 2010 and evaluated the dose-response relationships between environmental arsenic exposure indices or urinary arsenic profiles and the mortality of cause-specific cancer. A cohort of 1563 residents was conducted and collected their urine sample and information regarding arsenic exposure from a questionnaire. All-cause death was identified using the National Death Registry of Taiwan. Urinary arsenic profiles were measured using high performance liquid chromatography–hydride generator–atomic absorption spectrometry. We used Cox proportional hazard models to evaluate the mortality risks. In results, 193 all-site cancer deaths, and 29, 71, 43 deaths respectively for liver, lung and bladder cancers were ascertained. The SMRs were significantly high in arseniasis-endemic areas for liver, lung, and bladder cancers. People with high urinary InAs% or low DMA% or low secondary methylation index (SMI) were the most likely to suffer bladder cancer after adjusting other risk factors. Even stopping exposure to arsenic from the artesian well water, the mortality rates of the residents were higher than general population. Finally, urinary InAs%, DMA% and SMI could be the potential biomarkers to predict the mortality risk of bladder cancer. -- Highlights: ► The SMRs were significantly high in arseniasis-endemic areas for liver, lung, and bladder cancers. ► People with high urinary InAs% were the most likely to suffer bladder cancer. ► People with low DMA% or low SMI were the most likely to suffer bladder cancer

  1. The effect of cigarette smoke and arsenic exposure on urothelial carcinoma risk is modified by glutathione S-transferase M1 gene null genotype

    International Nuclear Information System (INIS)

    Inter-individual variation in the metabolism of xenobiotics, caused by factors such as cigarette smoking or inorganic arsenic exposure, is hypothesized to be a susceptibility factor for urothelial carcinoma (UC). Therefore, our study aimed to evaluate the role of gene–environment interaction in the carcinogenesis of UC. A hospital-based case–control study was conducted. Urinary arsenic profiles were measured using high-performance liquid chromatography–hydride generator-atomic absorption spectrometry. Genotyping was performed using a polymerase chain reaction-restriction fragment length polymorphism technique. Information about cigarette smoking exposure was acquired from a lifestyle questionnaire. Multivariate logistic regression was applied to estimate the UC risk associated with certain risk factors. We found that UC patients had higher urinary levels of total arsenic, higher percentages of inorganic arsenic (InAs%) and monomethylarsonic acid (MMA%) and lower percentages of dimethylarsinic acid (DMA%) compared to controls. Subjects carrying the GSTM1 null genotype had significantly increased UC risk. However, no association was observed between gene polymorphisms of CYP1A1, EPHX1, SULT1A1 and GSTT1 and UC risk after adjustment for age and sex. Significant gene–environment interactions among urinary arsenic profile, cigarette smoking, and GSTM1 wild/null polymorphism and UC risk were observed after adjustment for potential risk factors. Overall, gene–environment interactions simultaneously played an important role in UC carcinogenesis. In the future, large-scale studies should be conducted using tag-SNPs of xenobiotic-metabolism-related enzymes for gene determination. -- Highlights: ► Subjects with GSTM1 null genotype had significantly increased UC risk. ► UC patients had poor arsenic metabolic ability compared to controls. ► GSTM1 null genotype may modify arsenic related UC risk.

  2. Experiments on hadronic-atom x-ray intensities of hydrides and deuterides

    Energy Technology Data Exchange (ETDEWEB)

    Wiegand, C.E.; Lum, G.K.; Godfrey, G.L.

    1977-04-01

    Kaonic-atom x-ray intensities of elements Z = 3, 6, 8, 11, and 20 were significantly reduced when the elements were in hydride form. The ratios I (ZH/sub m/)/I (Z) have a noticeable Z dependence. Deuterides of C and O showed slightly less x-ray emission than their hydride counterparts.

  3. Study on the Use of Hydride Fuel in High-Performance Light Water Reactor Concept

    Directory of Open Access Journals (Sweden)

    Haileyesus Tsige-Tamirat

    2015-01-01

    Full Text Available Hydride fuels have features which could make their use attractive in future advanced power reactors. The potential benefit of use of hydride fuel in HPLWR without introducing significant modification in the current core design concept of the high-performance light water reactor (HPLWR has been evaluated. Neutronics and thermal hydraulic analyses were performed for a single assembly model of HPLWR with oxide and hydride fuels. The hydride assembly shows higher moderation with softer neutron spectrum and slightly more uniform axial power distribution. It achieves a cycle length of 18 months with sufficient excess reactivity. At Beginning of Cycle the fuel temperature coefficient of the hydride assembly is higher whereas the moderator and void coefficients are lower. The thermal hydraulic results show that the achievable fuel temperature in the hydride assembly is well below the design limits. The potential benefits of the use of hydride fuel in the current design of the HPLWR with the achieved improvements in the core neutronics characteristics are not sufficient to justify the replacement of the oxide fuel. Therefore for a final evaluation of the use of hydride fuels in HPLWR concepts additional studies which include modification of subassembly and core layout designs are required.

  4. Thermal and mechanical properties of zirconium hydrides with various hafnium contents

    International Nuclear Information System (INIS)

    Zirconium (Zr) hydride is currently expected as a neutron shield material for fast reactors. In order to evaluate safety and economic efficiency of the nuclear reactor, the thermal and mechanical properties of the hydride should be understood. In addition, since chemical properties of Zr and hafnium (Hf) are quite similar, Zr contains a few percent Hf generally. Therefore, it is very important to evaluate the effect of Hf content on the properties of Zr hydride. In the present study, fine bulk samples of δ-phase Zr hydrides with various Hf contents were prepared and their thermal and mechanical properties were investigated. We examined the phase states and the microstructure of the hydrides by means of X-ray diffraction and SEM/EDX analyses. In the temperature range from room temperature to 673 K, the heat capacity and the thermal diffusivity of the hydrides were measured and the thermal conductivity was evaluated. The Vickers hardness and the sound velocity of the hydrides were measured at room temperature, and the elastic modulus was calculated from the measured sound velocity. The effects of temperature and Hf content on the properties of Zr hydrides were studied. (author)

  5. Hydride precipitation and its influence on mechanical properties of notched and unnotched Zircaloy-4 plates

    International Nuclear Information System (INIS)

    The hydride formation and its influence on the mechanical performance of hydrided Zircaloy-4 plates containing different hydrogen contents were studied at room temperature. For the unnotched plate samples with the hydrogen contents ranging from 25 to 850 wt. ppm, the hydrides exerted an insignificant effect on the tensile strength, while the ductility was severely degraded with increasing hydrogen content. The fracture mode and degree of embrittlement were strongly related to the hydrogen content. When the hydrogen content reached a level of 850 wt. ppm, the plate exhibited negligible ductility, resulting in almost completely brittle behavior. For the hydrided notched plate, the tensile stress concentration associated with the notch tip facilitated the hydride accumulation at the region near the notch tip and the premature crack propagation through the hydride fracture during hydriding. The final brittle through-thickness failure for this notched sample was mainly attributed to the formation of a continuous hydride network on the thickness section and the obtained very high hydrogen concentration (estimated to be 1965 wt. ppm)

  6. Arsenic – Poison or medicine?

    Directory of Open Access Journals (Sweden)

    Karolina Kulik-Kupka

    2016-04-01

    Full Text Available Arsenic (As is commonly known as a poison. Only a few people know that As has also been widely used in medicine. In the past years As and its compounds were used as a medicine for the treatment of such diseases as diabetes, psoriasis, syphilis, skin ulcers and joint diseases. Nowadays As is also used especially in the treatment of patients with acute promyelocytic leukemia. The International Agency for Research on Cancer (IARC has recognized arsenic as an element with carcinogenic effect evidenced by epidemiological studies, but as previously mentioned it is also used in the treatment of neoplastic diseases. This underlines the specificity of the arsenic effects. Arsenic occurs widely in the natural environment, for example, it is present in soil and water, which contributes to its migration to food products. Long exposure to this element may lead to liver damages and also to changes in myocardium. Bearing in mind that such serious health problems can occur, monitoring of the As presence in the environmental media plays a very important role. In addition, the occupational risk of As exposure in the workplace should be identified and checked. Also the standards for As presence in food should be established. This paper presents a review of the 2015 publications based on the Medical database like PubMed and Polish Medical Bibliography. It includes the most important information about arsenic in both forms, poison and medicine. Med Pr 2016;67(1:89–96

  7. Mathematical modeling of the nickel/metal hydride battery system

    Energy Technology Data Exchange (ETDEWEB)

    Paxton, B K [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering

    1995-09-01

    A group of compounds referred to as metal hydrides, when used as electrode materials, is a less toxic alternative to the cadmium hydroxide electrode found in nickel/cadmium secondary battery systems. For this and other reasons, the nickel/metal hydride battery system is becoming a popular rechargeable battery for electric vehicle and consumer electronics applications. A model of this battery system is presented. Specifically the metal hydride material, LaNi{sub 5}H{sub 6}, is chosen for investigation due to the wealth of information available in the literature on this compound. The model results are compared to experiments found in the literature. Fundamental analyses as well as engineering optimizations are performed from the results of the battery model. In order to examine diffusion limitations in the nickel oxide electrode, a ``pseudo 2-D model`` is developed. This model allows for the theoretical examination of the effects of a diffusion coefficient that is a function of the state of charge of the active material. It is found using present data from the literature that diffusion in the solid phase is usually not an important limitation in the nickel oxide electrode. This finding is contrary to the conclusions reached by other authors. Although diffusion in the nickel oxide active material is treated rigorously with the pseudo 2-D model, a general methodology is presented for determining the best constant diffusion coefficient to use in a standard one-dimensional battery model. The diffusion coefficients determined by this method are shown to be able to partially capture the behavior that results from a diffusion coefficient that varies with the state of charge of the active material.

  8. Mineral resource of the month: arsenic

    Science.gov (United States)

    Brooks, William E.

    2008-01-01

    Arsenic has a long and varied history: Although it was not isolated as an element until the 13th century, it was known to the ancient Chinese, Egyptians and Greeks in compound form in the minerals arsenopyrite, realgar and orpiment. In the 1400s, “Scheele’s Green” was first used as an arsenic pigment in wallpaper, and leached arsenic from wallpaper may have contributed to Napoleon’s death in 1821. The 1940s play and later movie, Arsenic and Old Lace, dramatizes the metal’s more sinister role. Arsenic continues to be an important mineral commodity with many modern applications.

  9. Uranium-zirconium hydride TRIGA-LEU fuel

    International Nuclear Information System (INIS)

    The development and testing of TRIGA-LEU fuel with up to 45 wt-% U is described. Topics that are discussed include properties of hydride fuels, the prompt negative temperature coefficient, pulse heating tests, fission product retention, and the limiting design basis parameter and values. General specifications for Er-U-ZrH TRIGA-LEU fuel with 8.5 to 45 wt-% U and an outline of the inspections during manufacture of the fuel are also included. (author). 8 figs, 1 tab

  10. Hydride Ions, HCO+ and Ionizing Irradiation in Star Forming Region

    Science.gov (United States)

    Benz, Arnold O.; Bruderer, Simon; van Dishoeck, Ewine

    2016-06-01

    Hydrides are fundamental precursor molecules in cosmic chemistry and many hydride ions have become observable in high quality for the first time thanks to the Herschel Space Observatory. Ionized hydrides, such as CH+ and OH+ and also HCO+ affect the chemistry of molecules such as water. They also provide complementary information on irradiation by far UV (FUV) or X-rays and gas temperature.We explore hydrides of the most abundant heavier elements in an observational survey covering star forming regions with different mass and evolutionary state. Twelve YSOs were observed with HIFI on Herschel in 6 spectral settings providing fully velocity-resolved line profiles. The YSOs include objects of low (Class 0 and I), intermediate, and high mass, with luminosities ranging from 4 Ls to 2 105 Ls.The targeted lines of CH+, OH+, H2O+, and C+ are detected mostly in blue-shifted absorption. H3O+ and SH+ are detected in emission and only toward some high-mass objects. For the low-mass YSOs the column density ratios of CH+/OH+ can be reproduced by simple chemical models implying an FUV flux of 2 – 400 times the ISRF at the location of the molecules. In two high-mass objects, the UV flux is 20 – 200 times the ISRF derived from absorption lines, and 300 – 600 ISRF using emission lines. Upper limits for the X-ray luminosity can be derived from H3O+ observations for some low-mass objects.If the FUV flux required for low-mass objects originates at the central protostar, a substantial FUV luminosity, up to 1.5 Ls, is required. For high-mass regions, the FUV flux required to produce the observed molecular ratios is smaller than the unattenuated flux expected from the central object(s) at the Herschel beam radius. This is consistent with an FUV flux reduced by circumstellar extinction or by bloating of the protostar.The ion molecules are proposed to form in FUV irradiated cavity walls that are shocked by the disk wind. The shock region is turbulent, broadening the lines to some 1

  11. Research in Nickel/Metal Hydride Batteries 2016

    Directory of Open Access Journals (Sweden)

    Kwo-Hsiung Young

    2016-10-01

    Full Text Available Nineteen papers focusing on recent research investigations in the field of nickel/metal hydride (Ni/MH batteries have been selected for this Special Issue of Batteries. These papers summarize the joint efforts in Ni/MH battery research from BASF, Wayne State University, the National Institute of Standards and Technology, Michigan State University, and FDK during 2015–2016 through reviews of basic operational concepts, previous academic publications, issued US Patent and filed Japan Patent Applications, descriptions of current research results in advanced components and cell constructions, and projections of future works.

  12. The calculated rovibronic spectrum of scandium hydride, ScH

    CERN Document Server

    Lodi, Lorenzo; Tennyson\\, Jonathan

    2015-01-01

    The electronic structure of six low-lying electronic states of scandium hydride, $X\\,{}^{1}\\Sigma^+$, $a\\,{}^{3}\\Delta$, $b\\,{}^{3}\\Pi$, $A\\,{}^{1}\\Delta$ $c\\,{}^{3}\\Sigma^+$, and $B\\,{}^{1}\\Pi$, is studied using multi-reference configuration interaction as a function of bond length. Diagonal and off-diagonal dipole moment, spin-orbit coupling and electronic angular momentum curves are also computed. The results are benchmarked against experimental measurements and calculations on atomic scandium. The resulting curves are used to compute a line list of molecular ro-vibronic transitions for $^{45}$ScH.

  13. Alkyl and Hydride-Olefin Complexes of Niobocene

    NARCIS (Netherlands)

    Klazinga, A.H.; Teuben, J.H.

    1980-01-01

    Reactions of Cp2NbCl2 with RMgCl (R = n-C3H7, i-C3H7, n-C4H9, s-C4H9 and n-C5H11) give niobocene hydride olefin complexes Cp2Nb(H)L (L = C3H6, C4H8 and C5H10). The last step of the reaction probably proceeds via a stereospecific β-H elimination from the monoalkyl species Cp2NbR. Decomposition of n-a

  14. Electrochemical process and production of novel complex hydrides

    Science.gov (United States)

    Zidan, Ragaiy

    2013-06-25

    A process of using an electrochemical cell to generate aluminum hydride (AlH.sub.3) is provided. The electrolytic cell uses a polar solvent to solubilize NaAlH.sub.4. The resulting electrochemical process results in the formation of AlH.sub.3. The AlH.sub.3 can be recovered and used as a source of hydrogen for the automotive industry. The resulting spent aluminum can be regenerated into NaAlH.sub.4 as part of a closed loop process of AlH.sub.3 generation.

  15. Equilibrium composition for the reaction of plutonium hydride with air

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    There are six independent constituents with 4 chemical elements, i.e. PuH2.7(s), PuN(s), Pu2O3(s), N2, O2 and H2, therefore , the system described involves of 2 independent reactions ,both those of the experimental, which indicates that the chemical equilibrium is nearly completely approached. Therefore, it is believed that the reaction rate of plutonium hydride with air is extremely rapid. The present paper has briefly discussed the simultaneous reactions and its thermodynamic coupling effect.

  16. Comparison between different reactions of group IV hydride with H

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Shaolong; ZHANG; Xuqiang; ZHANG; Qinggang; ZHANG; Yici

    2006-01-01

    The four-dimensional time-dependent quantum dynamics calculations for reactions of group IV hydride with H are carried out by employing the semirigid vibrating rotor target model and the time-dependent wave packet method. The reaction possibility, cross section and rate constants for reactions (H+SiH4 and H+GeH4) in different initial vibrational and rotational states are obtained. The common feature for such kind of reaction process is summarized. The theoretical result is consistent with available measurement, which indicates the credibility of this theory and the potential energy surface.

  17. Another Look at the Mechanisms of Hydride Transfer Enzymes with Quantum and Classical Transition Path Sampling.

    Science.gov (United States)

    Dzierlenga, Michael W; Antoniou, Dimitri; Schwartz, Steven D

    2015-04-01

    The mechanisms involved in enzymatic hydride transfer have been studied for years, but questions remain due, in part, to the difficulty of probing the effects of protein motion and hydrogen tunneling. In this study, we use transition path sampling (TPS) with normal mode centroid molecular dynamics (CMD) to calculate the barrier to hydride transfer in yeast alcohol dehydrogenase (YADH) and human heart lactate dehydrogenase (LDH). Calculation of the work applied to the hydride allowed for observation of the change in barrier height upon inclusion of quantum dynamics. Similar calculations were performed using deuterium as the transferring particle in order to approximate kinetic isotope effects (KIEs). The change in barrier height in YADH is indicative of a zero-point energy (ZPE) contribution and is evidence that catalysis occurs via a protein compression that mediates a near-barrierless hydride transfer. Calculation of the KIE using the difference in barrier height between the hydride and deuteride agreed well with experimental results.

  18. Hydrogenation reaction characteristics and properties of its hydrides for magnetic regenerative material HoCu2

    Institute of Scientific and Technical Information of China (English)

    金滔; 吴梦茜; 黄迦乐; 汤珂; 陈立新

    2016-01-01

    The hydrogenation reaction characteristics and the properties of its hydrides for the magnetic regenerative material HoCu2 (CeCu2-type) of a cryocooler were investigated. The XRD testing reveals that the hydrides of HoCu2 were a mixture of Cu, unknown hydride I, and unknown hydride II. Based on the PCT (pressure−concentration−temperature) curves under different reaction temperatures, the relationships among reaction temperature, equilibrium pressure, and maximum hydrogen absorption capacity were analyzed and discussed. The enthalpy changeΔH and entropy changeΔS as a result of the whole hydrogenation process were also calculated from the PCT curves. The magnetization and volumetric specific heat capacity of the hydride were also measured by SQUID magnetometer and PPMS, respectively.

  19. Mobility and chemical bond of hydrogen in titanium and palladium hydrides

    International Nuclear Information System (INIS)

    The probabilities for π- meson capture by hydrogen are measured at 25, 155 and 200 deg C in TiHsub(1.65) hydride and at 25, -120 and -196 deg C in PdHsub(0.67) hydride. An analysis of the results obtained shows that within the accuracy of the measurements (approximately 10%) a sharp (up to 1012) change in the mobility of hydrogen in the hydrides induced by temperature changes within the ranges indicated does not noticeably affect the probabilities for π- meson capture by bound hydrogen, i.e. does not lead to appreciable changes in the Me-H bond. A comparison of the capture probabilities for palladium hydride and hydrides of neighboring transition metals shows that there are no pronounced anomalies in the Pd-H bond

  20. Arsenic contamination in food-chain: transfer of arsenic into food materials through groundwater irrigation.

    Science.gov (United States)

    Huq, S M Imamul; Joardar, J C; Parvin, S; Correll, Ray; Naidu, Ravi

    2006-09-01

    Arsenic contamination in groundwater in Bangladesh has become an additional concern vis-à-vis its use for irrigation purposes. Even if arsenic-safe drinking-water is assured, the question of irrigating soils with arsenic-laden groundwater will continue for years to come. Immediate attention should be given to assess the possibility of accumulating arsenic in soils through irrigation-water and its subsequent entry into the food-chain through various food crops and fodders. With this possibility in mind, arsenic content of 2,500 water, soil and vegetable samples from arsenic-affected and arsenic-unaffected areas were analyzed during 1999-2004. Other sources of foods and fodders were also analyzed. Irrigating a rice field with groundwater containing 0.55 mg/L of arsenic with a water requirement of 1,000 mm results in an estimated addition of 5.5 kg of arsenic per ha per annum. Concentration of arsenic as high as 80 mg per kg of soil was found in an area receiving arsenic-contaminated irrigation. A comparison of results from affected and unaffected areas revealed that some commonly-grown vegetables, which would usually be suitable as good sources of nourishment, accumulate substantially-elevated amounts of arsenic. For example, more than 150 mg/kg of arsenic has been found to be accumulated in arum (kochu) vegetable. Implications of arsenic ingested in vegetables and other food materials are discussed in the paper. PMID:17366772

  1. Arsenic-cadmium interaction in rats.

    Science.gov (United States)

    Díaz-Barriga, F; Llamas, E; Mejía, J J; Carrizales, L; Santoyo, M E; Vega-Vega, L; Yáñez, L

    1990-11-01

    Simultaneous exposure to cadmium and arsenic is highly probable in the urban area of San Luis Potosi, Mexico due to common localization of copper and zinc smelters. Therefore, in this work, rats were intraperitoneally exposed either to cadmium or arsenic alone, or simultaneously to both metals. The effects of these treatments on three different toxicological parameters were studied. Cadmium modified the LD50 of arsenic and conversely arsenic modified the LD50 for cadmium. At the histopathological level, arsenic appeared to protect against the cadmium effects, especially on testes. This protective effect seemed to be related to the glutathione levels found in this tissue: rats exposed to both arsenic and cadmium, presented glutathione values intermediate to those observed after exposure to either metal alone; arsenic had the highest value and cadmium the lowest. In liver, rats exposed to arsenic, cadmium or arsenic and cadmium, presented glutathione values below those in the saline group, with the lowest value corresponding to the arsenic and cadmium treatment. The results appear to support the proposed interaction between arsenic and cadmium and coexposure to both metals seems to alter certain effects produced by either metal alone. PMID:2219140

  2. Linking Microbial Activity with Arsenic Fate during Cow Dung Disposal of Arsenic-Bearing Wastes

    Science.gov (United States)

    Clancy, T. M.; Reddy, R.; Tan, J.; Hayes, K. F.; Raskin, L.

    2014-12-01

    To address widespread arsenic contamination of drinking water sources numerous technologies have been developed to remove arsenic. All technologies result in the production of an arsenic-bearing waste that must be evaluated and disposed in a manner to limit the potential for environmental release and human exposure. One disposal option that is commonly recommended for areas without access to landfills is the mixing of arsenic-bearing wastes with cow dung. These recommendations are made based on the ability of microorganisms to create volatile arsenic species (including mono-, di-, and tri-methylarsine gases) to be diluted in the atmosphere. However, most studies of environmental microbial communities have found only a small fraction (arsenic present in soils or rice paddies is released via volatilization. Additionally, past studies often have not monitored arsenic release in the aqueous phase. Two main pathways for microbial arsenic volatilization are known and include methylation of arsenic during methanogenesis and methylation by arsenite S-adenosylmethionine methyltransferase. In this study, we compare the roles of these two pathways in arsenic volatilization and aqueous mobilization through mesocosm experiments with cow dung and arsenic-bearing wastes produced during drinking water treatment in West Bengal, India. Arsenic in gaseous, aqueous, and solid phases was measured. Consistent with previous reports, less than 0.02% of the total arsenic present was volatilized. A much higher amount (~5%) of the total arsenic was mobilized into the liquid phase. Through the application of molecular tools, including 16S rRNA sequencing and quantification of gene transcripts involved in methanogenesis, this study links microbial community activity with arsenic fate in potential disposal environments. These results illustrate that disposal of arsenic-bearing wastes by mixing with cow dung does not achieve its end goal of promoting arsenic volatilization but rather appears to

  3. Formation of alloys in Ti-V system in hydride cycle and synthesis of their hydrides in self-propagating high-temperature synthesis regime

    Energy Technology Data Exchange (ETDEWEB)

    Aleksanyan, A.G., E-mail: a.g.aleks_yan@mail.ru [A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, 5/2 P.Sevak Str., Yerevan 0014 (Armenia); Dolukhanyan, S.K. [A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, 5/2 P.Sevak Str., Yerevan 0014 (Armenia); Shekhtman, V.Sh. [Institute of Solid State Physics, RAS, Chernogolovka, Moscow District 142432 (Russian Federation); Huot, J., E-mail: jacques_huot@uqtr.ca [Institut de recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres (Canada); Ter-Galstyan, O.P.; Mnatsakanyan, N.L. [A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, 5/2 P.Sevak Str., Yerevan 0014 (Armenia)

    2011-09-15

    Research highlights: > We synthesize Ti-V alloys by new 'hydride cycle' method. Structural characteristics of formed alloys we investigate by X-ray diffraction. > We show that the alloys contain mainly BCC crystal structure. > We investigate the interaction of the synthesized alloys with hydrogen in combustion regime. > We study the properties of hydrides by X-ray, DTA and DSC analyses. - Abstract: In the present work, the possibility of formation of titanium and vanadium based alloys of BCC structure using hydride cycle was investigated. The mechanism of formation of alloys in Ti-V system from the powders of hydrides TiH{sub 2} and VH{sub 0.9} (or of V) by compaction followed by dehydrogenation was studied. Then, the interaction of the synthesized alloys with hydrogen in combustion regime (self-propagating high-temperature synthesis, SHS) resulting in hydrides of these alloys was investigated. DTA and DSC analyses of some alloys and their hydrides were performed and their thermal characteristics were measured.

  4. Plant material as bioaccumulator of arsenic in soils affected by mining activities

    Science.gov (United States)

    Martínez-López, Salvadora; Martínez-Sánchez, Maria Jose; García-Lorenzo, Maria Luz; Pérez-Sirvent, Carmen

    2010-05-01

    Heavy metal contamination is an important environmental problem, since the metals are harmful to humans, animals and tend to bioaccumulate in the food chain. The aim of this study was to determine the total concentration of As, As (III) and As(V) in soil samples, leaves and roots of plant material, growing in a mining area in Spain (Murcia). Ditichia viscosa was used as the plant of reference. The concentrations of bioavailable As in plant samples were calculated by different soil chemical extraction methods; deionized water, 0.5N NaHCO3 (Olsen extraction), oxidizable medium, 0.5 HCl, 0.05M (NH4)2SO4, 0.005M DTPA and Mehra-Jackson extraction. For this study, fourteen samples were collected in the surrounding area of Sierra Minera and Portman Bay (Murcia, SE Spain). Samples were air dried and sieved to powder using an agate ball mill. Fresh vegetable samples were separated into root and aboveground biomass and then lyophilized. Arsenic levels were obtained by using atomic fluorescence spectrometry with an automated continuous flow hydride generation (HG-AFS) spectrometer. Samples showed pH average values close to neutrality. Most samples showed a very low organic matter percentage. Electrical conductivity and calcium carbonate content were considerably low in most samples. The mineralogical analysis showed that the main minerals were quartz, muscovite, kaolinite and illite, while the minority minerals were alteration products derived of mining activities (iron oxides and hydroxides, siderite, jarosite and gypsum), calcite and feldspars. Although the plants do not absorb arsenic in the same proportion, the results suggest that a good relationship exists between the total content of As in soil and the total content in plant. The results showed that the arsenic content in roots was positively correlated with the oxidizable-organic matter and sulfides fraction (oxidaizable medium extraction procedure). Arsenic concentration in leaves was positively correlated with the

  5. Groundwater arsenic contamination from parts of the Ghaghara Basin, India: influence of fluvial geomorphology and Quaternary morphostratigraphy

    Science.gov (United States)

    Shah, Babar Ali

    2016-09-01

    A groundwater arsenic (As) distribution in Faizabad, Gonda, and Basti districts of Uttar Pradesh is shown in the entrenched channels and floodplains of the Ghaghara River. Tubewell water samples were analysed for As through flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) system. About 38, 61, and 42 % of tubewells in Faizabad, Gonda, and Basti districts, respectively, have As >10 µg/l (WHO guideline). Moreover, 15, 45, and 26 % of tubewells in Faizabad, Gonda, and Basti districts, respectively, have As above 50 µg/l. About 86, 69, and 35 % of tubewells in Faizabad, Gonda, and Basti districts, respectively, are from shallow depth (21-45 m), and it is worth noticing that 47 % As-contaminated (As >10 µg/l) tubewells in these three districts are located within the depth of 10-35 m in Holocene Newer Alluvium aquifers. The high content of As (7.11 mg/kg) is measured in suspended river sediments of the Ghaghara River. Most of the As-contaminated villages in the Ghaghara Basin are located close to abandoned or present meander channels and floodplains of the Ghaghara River. In contrast, tubewells in Faizabad, Ayodhya, and Nawabganj towns are As-safe because of their positions on the Pleistocene Older Alluvium upland surfaces. Quaternary geomorphology plays an important role in groundwater arsenic contamination in the Ghaghara Basin. The sources of groundwater arsenic are geogenic and perennial mountainous rivers in the Ghaghara Basin supplied high sediment loads. The arsenic in groundwater of Ghaghara Basin is getting released from associated sediments which were likely deposited from the Himalayas. The process of release of groundwater arsenic is reductive dissolution of iron hydroxides.

  6. Managing hazardous pollutants in Chile: arsenic.

    Science.gov (United States)

    Sancha, Ana María; O'Ryan, Raul

    2008-01-01

    Chile is one of the few countries that faces the environmental challenge posed by extensive arsenic pollution, which exists in the northern part of the country. Chile has worked through various options to appropriately address the environmental challenge of arsenic pollution of water and air. Because of cost and other reasons, copying standards used elsewhere in the world was not an option for Chile. Approximately 1.8 million people, representing about 12% of the total population of the country, live in arsenic-contaminated areas. In these regions, air, water, and soil are contaminated with arsenic from both natural and anthropogenic sources. For long periods, water consumed by the population contained arsenic levels that exceeded values recommended by the World Health Organization. Exposure to airborne arsenic also occurred near several large cities, as a consequence of both natural contamination and the intensive mining activity carried out in those areas. In rural areas, indigenous populations, who lack access to treated water, were also exposed to arsenic by consuming foods grown locally in arsenic-contaminated soils. Health effects in children and adults from arsenic exposure first appeared in the 1950s. Such effects included vascular, respiratory, and skin lesions from intake of high arsenic levels in drinking water. Methods to remove arsenic from water were evaluated, developed, and implemented that allowed significant reductions in exposure at a relatively low cost. Construction and operation of treatment plants to remove arsenic from water first began in the 1970s. Beginning in the 1990s, epidemiological studies showed that the rate of lung and bladder cancer in the arsenic-polluted area was considerably higher than mean cancer rates for the country. Cancer incidence was directly related to arsenic exposure. During the 1990s, international pressure and concern by Chile's Health Ministry prompted action to regulate arsenic emissions from copper smelters. A

  7. Separation of covalent hydrides by gas-solid chromatography

    International Nuclear Information System (INIS)

    A fully automated method was developed for separating the hydrides of elements of the IVth to VIIIth main subgroup of the periodic system and of Kr and Xe on the basis of their volatility using gas chromatography. The automated instrument allowing to carry out reduction, separation of the gaseous phase, the loading of a PORAPAK-packed column, the chromatographic separation and sampling was controlled by a HP 2116B computer. The elution time, peak area and the number of theoretical column plates were computed from chromatograms. The capture probably proceeded by a type of nonpolar nonspecific sorption (ΔH/Tsub(b) = 19.2 cal/mol.deg). The height of the theoretical plate was 0.05 to 0.1 cm. The technique may be used as a routine radiochemical method for group separations and for the separation of radioactive hydrides contained in the solution of targets irradiated with neutrons or charged particles in the preparation of radioactive sources of short-lived radionuclides, or in destructive activation analysis. (M.K.)

  8. Reactions of ruthenium hydrides with ethyl-vinyl sulfide.

    Science.gov (United States)

    Dahcheh, Fatme; Stephan, Douglas W

    2014-03-01

    The Ru-hydride precursors (Im(OMe)2)(PPh3)2RuHCl () and (Me2Im(OMe)2)(PPh3)2RuHCl () reacted with ethyl-vinyl-sulfide to give ((MeOCH2CH2)C3H2N2(CH2CH(OMe))RuCl(PPh3)2 () and ((MeOCH2CH2)C3Me2N2(CH2CH(OMe))RuCl(PPh3)2 (), respectively. Dissolution of () in C6D6 prompts formation of ((MeOCH2CH2)C5H6N2(CHCH)RuCl(PPh3)2 (). The analogous reactions of the bis-carbene Ru-hydride precursors (Im(OMe)2)(IMes)(PPh3)RuHCl (), (Im(OMe)2)(SIMes)(PPh3)RuHCl () and (Im(OMe)2)(IMes-Cl2)(PPh3)RuHCl () gave ((MeOCH2CH2)C3H2N2(CHCH)RuCl(PPh3)(NHC) (NHC = IMes (), SIMes (), IMes-Cl2 (), respectively. The formation of compounds () and () is thought to go through an initial insertion of the vinyl-fragment into the Ru-H prompting subsequent C-H activation and loss of diethyl sulfide. This yields () and (), while subsequent loss of methanol yields () and (-). PMID:24441082

  9. Electronic structure of the palladium hydride studied by compton scattering

    CERN Document Server

    Mizusaki, S; Yamaguchi, M; Hiraoka, N; Itou, M; Sakurai, Y

    2003-01-01

    The hydrogen-induced changes in the electronic structure of Pd have been investigated by Compton scattering experiments associated with theoretical calculations. Compton profiles (CPs) of single crystal of Pd and beta phase hydride PdH sub x (x=0.62-0.74) have been measured along the [100], [110] and [111] directions with a momentum resolution of 0.14-0.17 atomic units using 115 keV x-rays. The theoretical Compton profiles have been calculated from the wavefunctions obtained utilizing the full potential linearized augmented plane wave method within the local density approximation for Pd and stoichiometric PdH. The experimental and the theoretical results agreed well with respect to the difference in the CPs between PdH sub x and Pd, and the anisotropy in the CPs of Pd or PdH sub x. This study provides lines of evidence that upon hydride formation the lowest valance band of Pd is largely modified due to hybridization with H 1s-orbitals and the Fermi energy is raised into the sp-band. (author)

  10. Gallium Nitride Nanowires Grown by Hydride Vapor Phase Epitaxy

    Institute of Scientific and Technical Information of China (English)

    LIU Zhan-Hui; XIU Xiang-Qan; YAN Huai-Yue; ZHANG Rong; XIE Zi-Li; HAN Ping; SHI Yi; ZHENG You-Dou

    2011-01-01

    @@ GaN nanowires are grown by hydride vapor phase epitaxy using nickel as a catalyst.The properties of the obtained GaN nanowires are characterized by scanning and transmission electron microscopy,electron diffraction,roomtemperature photoluminescence and energy dispersive spectroscopy.The results show that the nanowires are wurtzite single crystals growing along the[0001]direction and a redshift in the photoluminescence is observed due to a superposition of several effects.The Raman spectra are close to those of the bulk GaN and the significantly broadening of those modes indicates the phonon confinement effects associated with the nanoscale dimensions of the system.%GaN nanowires are grown by hydride vapor phase epitaxy using nickel as a catalyst. The properties of the obtained GaN nanowires are characterized by scanning and transmission electron microscopy, electron diffraction, room-temperature photoluminescence and energy dispersive spectroscopy. The results show that the nanowires are wurtzite single crystals growing along the [0001] direction and a redshift in the photoluminescence is observed due to a superposition of several effects. The Raman spectra are close to those of the bulk GaN and the significantly broadening of those modes indicates the phonon confinement effects associated with the nanoscale dimensions of the system.

  11. Thermodynamic Calculation on the Formation of Titanium Hydride

    Institute of Scientific and Technical Information of China (English)

    Jing-wei Zhao; Hua Ding; Xue-feng Tian; Wen-juan Zhao; Hong-liang Hou

    2008-01-01

    A modified Miedema model, using interrelationship among the basic properties of elements Ti and H, is employed to calculate the standard enthalpy of formation of titanium hydride TiHx (1≤x≤2). Based on Debye theories of solid thermal capacity, the vibrational entropy, as well as electronic entropy, is acquired by quantum mechanics and statistic thermodynamics methods, and a new approach is presented to calculate the standard entropy of formation of Till2. The values of standard enthalpy of formation of TiHx decrease linearly with increase of x. The calculated results of standard enthalpy, entropy, and free energy of forma- tion of Till2 at 298.16 K are -142.39 kJ/mol, -143.0 J/(mol-K) and -99.75 k J/tool, respectively, which is consistent with the previously-reported data obtained by either experimental or theoretical calculation methods. The results show that the thermodynamic model for titanium hydride is reasonable.

  12. Measurement of nuclear fuel pin hydriding utilizing epithermal neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Miller, W.H. [Univ. of Missouri, Columbia, MO (United States); Farkas, D.M.; Lutz, D.R. [General Electric Co., Pleasanton, CA (United States)

    1996-12-31

    The measurement of hydrogen or zirconium hydriding in fuel cladding has long been of interest to the nuclear power industry. The detection of this hydrogen currently requires either destructive analysis (with sensitivities down to 1 {mu}g/g) or nondestructive thermal neutron radiography (with sensitivities on the order of a few weight percent). The detection of hydrogen in metals can also be determined by measuring the slowing down of neutrons as they collide and rapidly lose energy via scattering with hydrogen. This phenomenon is the basis for the {open_quotes}notched neutron spectrum{close_quotes} technique, also referred to as the Hysen method. This technique has been improved with the {open_quotes}modified{close_quotes} notched neutron spectrum technique that has demonstrated detection of hydrogen below 1 {mu}g/g in steel. The technique is nondestructive and can be used on radioactive materials. It is proposed that this technique be applied to the measurement of hydriding in zirconium fuel pins. This paper summarizes a method for such measurements.

  13. Method of generating hydrogen-storing hydride complexes

    Science.gov (United States)

    Srinivasan, Sesha S; Niemann, Michael U; Goswami, D. Yogi; Stefanakos, Elias K

    2013-05-14

    A ternary hydrogen storage system having a constant stoichiometric molar ratio of LiNH.sub.2:MgH.sub.2:LiBH.sub.4 of 2:1:1. It was found that the incorporation of MgH.sub.2 particles of approximately 10 nm to 20 nm exhibit a lower initial hydrogen release temperature of 150.degree. C. Furthermore, it is observed that the particle size of LiBNH quaternary hydride has a significant effect on the hydrogen sorption concentration with an optimum size of 28 nm. The as-synthesized hydrides exhibit two main hydrogen release temperatures, one around 160.degree. C. and the other around 300.degree. C., with the main hydrogen release temperature reduced from 310.degree. C. to 270.degree. C., while hydrogen is first reversibly released at temperatures as low as 150.degree. C. with a total hydrogen capacity of 6 wt. % to 8 wt. %. Detailed thermal, capacity, structural and microstructural properties have been demonstrated and correlated with the activation energies of these materials.

  14. Superconductive "sodalite"-like clathrate calcium hydride at high pressures

    CERN Document Server

    Wang, Hui; Tanaka, Kaori; Iitaka, Toshiaki; Ma, Yanming

    2012-01-01

    Hydrogen-rich compounds hold promise as high-temperature superconductors under high pressures. Recent theoretical hydride structures on achieving high-pressure superconductivity are composed mainly of H2 fragments. Through a systematic investigation of Ca hydrides with different hydrogen contents using particle-swam optimization structural search, we show that in the stoichiometry CaH6 a body-centred cubic structure with hydrogen that forms unusual "sodalite" cages containing enclathrated Ca stabilizes above pressure 150 GPa. The stability of this structure is derived from the acceptance by two H2 of electrons donated by Ca forming a "H4" unit as the building block in the construction of the 3-dimensional sodalite cage. This unique structure has a partial occupation of the degenerated orbitals at the zone centre. The resultant dynamic Jahn-Teller effect helps to enhance electron-phonon coupling and leads to superconductivity of CaH6. A superconducting critical temperature (Tc) of 220-235 K at 150 GPa obtained...

  15. A quantitative phase field model for hydride precipitation in zirconium alloys: Part I. Development of quantitative free energy functional

    International Nuclear Information System (INIS)

    A temperature dependent, quantitative free energy functional was developed for the modeling of hydride precipitation in zirconium alloys within a phase field scheme. The model takes into account crystallographic variants of hydrides, interfacial energy between hydride and matrix, interfacial energy between hydrides, elastoplastic hydride precipitation and interaction with externally applied stress. The model is fully quantitative in real time and real length scale, and simulation results were compared with limited experimental data available in the literature with a reasonable agreement. The work calls for experimental and/or theoretical investigations of some of the key material properties that are not yet available in the literature

  16. Effects of plant arsenic uptake and heavy metals on arsenic distribution in an arsenic-contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Fayiga, Abioye O. [Soil and Water Science Department, University of Florida, Gainesville, FL 32611-0290 (United States); Ma, Lena Q. [Soil and Water Science Department, University of Florida, Gainesville, FL 32611-0290 (United States) and Key Laboratory of Terrestrial Ecological Process, Chinese Academy of Sciences, Shenyang 110016 (China)]. E-mail: lqma@ifas.ufl.edu; Zhou Qixing [Key Laboratory of Terrestrial Ecological Process, Chinese Academy of Sciences, Shenyang 110016 (China)

    2007-06-15

    This study examined the effects of heavy metals and plant arsenic uptake on soil arsenic distribution. Chemical fractionation of an arsenic-contaminated soil spiked with 50 or 200 mg kg{sup -1} Ni, Zn, Cd or Pb was performed before and after growing the arsenic hyperaccumulator Pteris vittata L for 8 weeks using NH{sub 4}Cl (water-soluble plus exchangeable, WE-As), NH{sub 4}F (Al-As), NaOH (Fe-As), and H{sub 2}SO{sub 4} (Ca-As). Arsenic in the soil was present primarily as the recalcitrant forms with Ca-As being the dominant fraction (45%). Arsenic taken up by P. vittata was from all fractions though Ca-As contributed the most (51-71% reduction). After 8 weeks of plant growth, the Al-As and Fe-As fractions were significantly (p < 0.01) greater in the metal-spiked soils than the control, with changes in the WE-As fraction being significantly (p = 0.007) correlated with plant arsenic removal. The plant's ability to solubilize soil arsenic from recalcitrant fractions may have enhanced its ability to hyperaccumulate arsenic. - Arsenic taken up by P. vittata was from all fractions with most from the Ca-fraction.

  17. Urinary Arsenic Metabolites of Subjects Exposed to Elevated Arsenic Present in Coal in Shaanxi Province, China

    Directory of Open Access Journals (Sweden)

    Linsheng Yang

    2011-06-01

    Full Text Available In contrast to arsenic (As poisoning caused by naturally occurring inorganic arsenic-contaminated water consumption, coal arsenic poisoning (CAP induced by elevated arsenic exposure from coal combustion has rarely been reported. In this study, the concentrations and distributions of urinary arsenic metabolites in 57 volunteers (36 subjects with skin lesions and 21 subjects without skin lesions, who had been exposed to elevated levels of arsenic present in coal in Changshapu village in the south of Shaanxi Province (China, were reported. The urinary arsenic species, including inorganic arsenic (iAs [arsenite (iAsIII and arsenate (iAsV], monomethylarsonic acid (MMAV and dimethylarsinic acid (DMAV, were determined by high-performance liquid chromatography (HPLC combined with inductively coupled plasma mass spectroscopy (ICP-MS. The relative distributions of arsenic species, the primary methylation index (PMI = MMAV/iAs and the secondary methylation index (SMI = DMAV/MMAV were calculated to assess the metabolism of arsenic. Subjects with skin lesions had a higher concentration of urinary arsenic and a lower arsenic methylation capability than subjects without skin lesions. Women had a significantly higher methylation capability of arsenic than men, as defined by a higher percent DMAV and SMI in urine among women, which was the one possible interpretation of women with a higher concentration of urinary arsenic but lower susceptibility to skin lesions. The findings suggested that not only the dose of arsenic exposure but also the arsenic methylation capability have an impact on the individual susceptibility to skin lesions induced by coal arsenic exposure.

  18. Chronic arsenic poisoning from burning high-arsenic-containing coal in Guizhou, China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J.; Zheng, B.S.; Aposhian, H.V.; Zhou, Y.S.; Chen, M.L.; Zhang, A.H.; Waalkes, M.P. [NIEHS, Research Triangle Park, NC (USA)

    2002-07-01

    Arsenic is an environmental hazard and the reduction of drinking water arsenic levels is under consideration. People are exposed to arsenic not only through drinking water but also through arsenic-contaminated air and food. Here the health effects of arsenic exposure from burning high arsenic-containing coal in Guizhou, China was investigated. Coal is burned inside the home in open pits for daily cooking and crop drying, producing a high concentration of arsenic in indoor air. Arsenic in the air coats and permeates food being dried producing high concentrations in food; however, arsenic concentrations in the drinking water are in the normal range. The estimated sources of total arsenic exposure in this area are from arsenic-contaminated food (50-80%), air (10-20%), water (1-5%), and direct contact in coal-mining workers (1%). At least 3,000 patients with arsenic poisoning were found in the Southwest Prefecture of Guizhou, and approximately 200,000 people are at risk for such over exposures. Skin lesions are common, including keratosis of the hands and feet, pigmentation on the trunk, skin ulceration, and skin cancers. Toxicities to internal organs, including lung dysfunction, neuropathy, and nephrotoxicity, are clinically evident. The prevalence of hepatomegaly was 20%, and cirrhosis, ascites, and liver cancer are the most serious outcomes of arsenic poisoning. The Chinese government and international organizations are attempting to improve the house conditions and the coal source, and thereby protect human health in this area.

  19. Linking Microbial Activity with Arsenic Fate during Cow Dung Disposal of Arsenic-Bearing Wastes

    Science.gov (United States)

    Clancy, T. M.; Reddy, R.; Tan, J.; Hayes, K. F.; Raskin, L.

    2014-12-01

    To address widespread arsenic contamination of drinking water sources numerous technologies have been developed to remove arsenic. All technologies result in the production of an arsenic-bearing waste that must be evaluated and disposed in a manner to limit the potential for environmental release and human exposure. One disposal option that is commonly recommended for areas without access to landfills is the mixing of arsenic-bearing wastes with cow dung. These recommendations are made based on the ability of microorganisms to create volatile arsenic species (including mono-, di-, and tri-methylarsine gases) to be diluted in the atmosphere. However, most studies of environmental microbial communities have found only a small fraction (cow dung and arsenic-bearing wastes produced during drinking water treatment in West Bengal, India. Arsenic in gaseous, aqueous, and solid phases was measured. Consistent with previous reports, less than 0.02% of the total arsenic present was volatilized. A much higher amount (~5%) of the total arsenic was mobilized into the liquid phase. Through the application of molecular tools, including 16S rRNA sequencing and quantification of gene transcripts involved in methanogenesis, this study links microbial community activity with arsenic fate in potential disposal environments. These results illustrate that disposal of arsenic-bearing wastes by mixing with cow dung does not achieve its end goal of promoting arsenic volatilization but rather appears to increase arsenic mobilization in the aqueous phase, raising concerns with this approach.

  20. Arsenic in Drinking Water-A Global Environmental Problem

    Science.gov (United States)

    Wang, Joanna Shaofen; Wai, Chien M.

    2004-01-01

    Information on the worldwide occurrence of groundwater pollution by arsenic, the ensuing health hazards, and the debatable government regulations of arsenic in drinking water, is presented. Diagnostic identification of arsenic, and methods to eliminate it from water are also discussed.

  1. Poisoning of bees by industrial arsenic emissions

    Energy Technology Data Exchange (ETDEWEB)

    Jaroslav, S.

    1962-01-01

    Massive poisoning of bees by industrial arsenic emissions in Czechoslovakia are reviewed. Arsenic emissions from an ore processing plant in Tesin were responsible for massive bee deaths after World War I. Massive death of bees was observed in 1938 in the Krompach region around a copper ore smelting plant which emitted arsenic. Other accidents were reported in 1954 and 1957 in areas around industrial plants and power plants using arsenopyrite-containing low-grade coal or lignite. Arsenic was emitted bound in fly-ash in the form of arsenic trioxide or, in the case of coals containing alkaline chlorides, in the form of arsenic trichloride. The arsenic contamination extended to areas within a radius of 3 to 7 km. Settled fly-ash contained 0.0004 to 0.75 percent arsenic, which was soluble in a citrate-hydrochloric acid solution of pH 3.9, which corresponds to the gastric acid of bees. The arsenic uptake by the bees from pollen was calculated to amount to 1 microgram daily, against a toxic dose of 0.37 microgram. The toxic effect of arsenic on bees can be abated by adding colloidal iron hydroxide to the sugar solution which they are fed.

  2. Poisoning of bees by industrial arsenic emissions

    Energy Technology Data Exchange (ETDEWEB)

    Svoboda, J.

    1962-01-01

    Massive poisoning of bees by industrial arsenic emissions in Czechoslovakia are reviewed. Arsenic emissions from an ore processing plant in Tesin were responsible for massive bee deaths after World War I. Massive death of bees was observed in 1938 in the Krompach region around a copper ore smelting plant which emitted arsenic. Other accidents were reported in 1954 and 1957 in areas around industrial plants and power plants using arsenopyrite-containing low-grade coal or lignite. Arsenic was emitted bound in fly-ash in the form of arsenic trioxide or, in the case of coals containing alkaline chlorides, in the form of arsenic trichloride. The arsenic contamination extended to areas within a radius of 3-7 km. Settled fly-ash contained 0.0004-0.75% arsenic, which was soluble in a citrate-hydrochloric acid solution of pH 3.9, which corresponds to the gastric acid of bees. The arsenic uptake by the bees from pollen was calculated to amount to 1 microgram daily, against a toxic dose of 0.37 microgram. The toxic effect of arsenic on bees can be abated by adding colloidal iron hydroxide to the sugar solution which they are fed. 5 references.

  3. Epidemiologic evidence of diabetogenic effect of arsenic.

    Science.gov (United States)

    Tseng, Chin-Hsiao; Tseng, Ching-Ping; Chiou, Hung-Yi; Hsueh, Yu-Mei; Chong, Choon-Khim; Chen, Chien-Jen

    2002-07-01

    It is well documented that arsenic can lead to skin lesions, atherosclerotic diseases and cancers. The association between arsenic exposure and diabetes mellitus is a relatively new finding. Up to now, there are six epidemiologic reports linking diabetes mellitus with arsenic exposure from environmental and occupational sources. Two reports in Taiwan carried out in the blackfoot disease-hyperendemic villages, one cross-sectional and one prospective follow-up of the same cohort, indicate that arsenic exposure from drinking artesian well water is associated with prevalence and incidence of diabetes mellitus in a dose-responsive pattern. The observation of the relation between arsenic exposure and diabetes mellitus is further supported by studies carried out in Sweden and Bangladesh. In Sweden, case-control analyses of death records of copper smelters and glass workers revealed a trend of increasing diabetes mellitus with increasing arsenic exposure from inhalation. In Bangladesh, prevalence of diabetes mellitus among arsenic-exposed subjects with keratosis was about five times higher than unexposed subjects. Increasing trends of diabetes mellitus with indices of arsenic exposure in drinking water seems to be independent of the presence of skin lesions associated with arsenic exposure. Although these studies consistently show an association between arsenic exposure and diabetes mellitus, the weak study designs of cross-sectional or case-control, the use of glucosuria or diabetes death as diagnostic criteria and the lack of adjustment for possible confounders in some studies, are major limitations that may reduce the strength of the evidence. PMID:12076511

  4. Sequestration of arsenic in ombrotrophic peatlands

    Science.gov (United States)

    Rothwell, James; Hudson-Edwards, Karen; Taylor, Kevin; Polya, David; Evans, Martin; Allott, Tim

    2014-05-01

    Peatlands can be important stores of arsenic but we are lacking spectroscopic evidence of the sequestration pathways of this toxic metalloid in peatland environments. This study reports on the solid-phase speciation of anthropogenically-derived arsenic in atmospherically contaminated peat from the Peak District National Park (UK). Surface and sub-surface peat samples were analysed by synchrotron X-ray absorption spectroscopy on B18 beamline at Diamond Light Source (UK). The results suggest that there are contrasting arsenic sequestration mechanisms in the peat. The bulk arsenic speciation results, in combination with strong arsenic-iron correlations at the surface, suggest that iron (hydr)oxides are key phases for the immobilisation of arsenic at the peat surface. In contrast, the deeper peat samples are dominated by arsenic sulphides (arsenopyrite, realgar and orpiment). Given that these peats receive inputs solely from the atmosphere, the presence of these sulphide phases suggests an in-situ authigenic formation. Redox oscillations in the peat due to a fluctuating water table and an abundant store of legacy sulphur from historic acid rain inputs may favour the precipitation of arsenic sequestering sulphides in sub-surface horizons. Oxidation-induced loss of these arsenic sequestering sulphur species by water table drawdown has important implications for the mobility of arsenic and the quality of waters draining peatlands.

  5. Arsenic removal from drinking water during coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Hering, J.G. [California Inst. of Tech., Pasadena, CA (United States); Chen, P.Y. [Industrial Technology Research Inst., Chutung Hsinchu (Taiwan, Province of China); Wilkie, J.A.; Elimelech, M. [Univ. of California, Los Angeles, CA (United States). Dept. of Civil and Environmental Engineering

    1997-08-01

    The efficiency of arsenic removal from source waters and artificial freshwaters during coagulation with ferric chloride and alum was examined in bench-scale studies. Arsenic(V) removal by either ferric chloride or alum was relatively insensitive to variations in source water composition below pH 8. At pH 8 and 9, the efficiency of arsenic(V) removal by ferric chloride was decreased in the presence of natural organic matter. The pH range for arsenic(V) removal with alum was more restricted than with ferric chloride. For source waters spiked with 20 {micro}g/L arsenic(V), final dissolved arsenic(V) concentrations in the product water of less than 2 {micro}g/L were achieved with both coagulants at neutral pH. Removal of arsenic(III) from source waters by ferric chloride was both less efficient and more strongly influenced by source water composition than removal of arsenic(V). The presence of sulfate (at pH 4 and 5) and natural organic matter (at pH 4 through 9) adversely affected the efficiency of arsenic(III) removal by ferric chloride. Arsenic(III) could not be removed from source waters by coagulation with alum.

  6. Main Group Lewis Acid-Mediated Transformations of Transition-Metal Hydride Complexes.

    Science.gov (United States)

    Maity, Ayan; Teets, Thomas S

    2016-08-10

    This Review highlights stoichiometric reactions and elementary steps of catalytic reactions involving cooperative participation of transition-metal hydrides and main group Lewis acids. Included are reactions where the transition-metal hydride acts as a reactant as well as transformations that form the metal hydride as a product. This Review is divided by reaction type, illustrating the diverse roles that Lewis acids can play in mediating transformations involving transition-metal hydrides as either reactants or products. We begin with a discussion of reactions where metal hydrides form direct adducts with Lewis acids, elaborating the structure and dynamics of the products of these reactions. The bulk of this Review focuses on reactions where the transition metal and Lewis acid act in cooperation, and includes sections on carbonyl reduction, H2 activation, and hydride elimination reactions, all of which can be promoted by Lewis acids. Also included is a section on Lewis acid-base secondary coordination sphere interactions, which can influence the reactivity of hydrides. Work from the past 50 years is included, but the majority of this Review focuses on research from the past decade, with the intent of showcasing the rapid emergence of this field and the potential for further development into the future. PMID:27164024

  7. Acute arsenic poisoning diagnosed late.

    Science.gov (United States)

    Shumy, Farzana; Anam, Ahmad Mursel; Kamruzzaman, A K M; Amin, Md Robed; Chowdhury, M A Jalil

    2016-04-01

    Acute arsenicosis, although having a 'historical' background, is not common in our times. This report describes a case of acute arsenic poisoning, missed initially due to its gastroenteritis-like presentation, but suspected and confirmed much later, when the patient sought medical help for delayed complications after about 2 months.

  8. The microbial genomics of arsenic.

    Science.gov (United States)

    Andres, Jérémy; Bertin, Philippe N

    2016-03-01

    Arsenic, which is a major contaminant of many aquatic ecosystems worldwide, is responsible for serious public health issues. However, life has evolved various strategies for coping with this toxic element. In particular, prokaryotic organisms have developed processes enabling them to resist and metabolize this chemical. Studies based on genome sequencing and transcriptome, proteome and metabolome profiling have greatly improved our knowledge of prokaryotes' metabolic potential and functioning in contaminated environments. The increasing number of genomes available and the development of descriptive and comparative approaches have made it possible not only to identify several genetic determinants of the arsenic metabolism, but also to elucidate their phylogenetic distribution and their modes of regulation. In addition, studies using functional genomic tools have established the pleiotropic character of prokaryotes' responses to arsenic, which can be either common to several species or species-specific. These approaches also provide promising means of deciphering the functioning of microbial communities including uncultured organisms, the genetic transfers involved and the possible occurrence of metabolic interactions as well as the evolution of arsenic resistance and metabolism.

  9. Acute arsenic poisoning diagnosed late.

    Science.gov (United States)

    Shumy, Farzana; Anam, Ahmad Mursel; Kamruzzaman, A K M; Amin, Md Robed; Chowdhury, M A Jalil

    2016-04-01

    Acute arsenicosis, although having a 'historical' background, is not common in our times. This report describes a case of acute arsenic poisoning, missed initially due to its gastroenteritis-like presentation, but suspected and confirmed much later, when the patient sought medical help for delayed complications after about 2 months. PMID:26508422

  10. Bimetallic nanoparticles for arsenic detection.

    Science.gov (United States)

    Moghimi, Nafiseh; Mohapatra, Mamata; Leung, Kam Tong

    2015-06-01

    Effective and sensitive monitoring of heavy metal ions, particularly arsenic, in drinking water is very important to risk management of public health. Arsenic is one of the most serious natural pollutants in soil and water in more than 70 countries in the world. The need for very sensitive sensors to detect ultralow amounts of arsenic has attracted great research interest. Here, bimetallic FePt, FeAu, FePd, and AuPt nanoparticles (NPs) are electrochemically deposited on the Si(100) substrate, and their electrochemical properties are studied for As(III) detection. We show that trace amounts of As(III) in neutral pH could be determined by using anodic stripping voltammetry. The synergistic effect of alloying with Fe leads to better performance for Fe-noble metal NPs (Au, Pt, and Pd) than pristine noble metal NPs (without Fe alloying). Limit of detection and linear range are obtained for FePt, FeAu, and FePd NPs. The best performance is found for FePt NPs with a limit of detection of 0.8 ppb and a sensitivity of 0.42 μA ppb(-1). The selectivity of the sensor has also been tested in the presence of a large amount of Cu(II), as the most detrimental interferer ion for As detection. The bimetallic NPs therefore promise to be an effective, high-performance electrochemical sensor for the detection of ultratrace quantities of arsenic. PMID:25938763

  11. Arsenic chemistry in soils and sediments

    Energy Technology Data Exchange (ETDEWEB)

    Fendorf, S.; Nico, P.; Kocar, B.D.; Masue, Y.; Tufano, K.J.

    2009-10-15

    Arsenic is a naturally occurring trace element that poses a threat to human and ecosystem health, particularly when incorporated into food or water supplies. The greatest risk imposed by arsenic to human health results from contamination of drinking water, for which the World Health Organization recommends a maximum limit of 10 {micro}g L{sup -1}. Continued ingestion of drinking water having hazardous levels of arsenic can lead to arsenicosis and cancers of the bladder, skin, lungs and kidneys. Unfortunately, arsenic tainted drinking waters are a global threat and presently having a devastating impact on human health within Asia. Nearly 100 million people, for example, are presently consuming drinking water having arsenic concentrations exceeding the World Health Organization's recommended limit (Ahmed et al., 2006). Arsenic contamination of the environment often results from human activities such as mining or pesticide application, but recently natural sources of arsenic have demonstrated a devastating impact on water quality. Arsenic becomes problematic from a health perspective principally when it partitions into the aqueous rather than the solid phase. Dissolved concentrations, and the resulting mobility, of arsenic within soils and sediments are the combined result of biogeochemical processes linked to hydrologic factors. Processes favoring the partitioning of As into the aqueous phase, potentially leading to hazardous concentrations, vary extensively but can broadly be grouped into four categories: (1) ion displacement, (2) desorption (or limited sorption) at pH values > 8.5, (3) reduction of arsenate to arsenite, and (4) mineral dissolution, particularly reductive dissolution of Fe and Mn (hydr)oxides. Although various processes may liberate arsenic from solids, a transition from aerobic to anaerobic conditions, and commensurate arsenic and iron/manganese reduction, appears to be a dominant, but not exclusive, means by which high concentrations of

  12. Characterization of Al{sub x}Ga{sub 1-x}As/GaAs heterostructures for single quantum wells grown by a solid arsenic MOCVD system

    Energy Technology Data Exchange (ETDEWEB)

    Castillo-Ojeda, R. [Universidad Politecnica de Pachuca, Km. 20, Rancho Luna, Ex-Hacienda de Santa Barbara, Municipio de Zempoala, Hidalgo 43830 (Mexico); Diaz-Reyes, J., E-mail: jdiazr2001@yahoo.co [Instituto Politecnico Nacional, Centro de Investigacion en Biotecnologia Aplicada, CIBA-IPN, Ex Hacienda de San Juan Molino, Km. 1.5. Tepetitla, Tlaxcala 90700 (Mexico); Galvan-Arellano, M.; Pena-Sierra, R. [CINVESTAV-IPN, Depto. de Ing. Electrica, SEES. Apdo. 14-740, Mexico, D.F. 07000 (Mexico)

    2011-06-15

    This work presents the results of the growth and characterization of Al{sub x}Ga{sub 1-x}As/GaAs multilayer structures obtained in a metallic-arsenic-based-MOCVD system. The main goal is to explore the ability of the growth system to grow high quality multilayer structures like quantum wells. The use of metallic arsenic could introduce important differences in the growth process due to the absence of the hydride group V precursor (AsH{sub 3}), which manifests in the electrical and optical characteristics of both GaAs and Al{sub x}Ga{sub 1-x}As layers. The characterization of these epilayers and structures was performed using low-temperature photoluminescence, Hall effect measurements, X-ray diffraction, Raman spectroscopy, secondary ion mass spectroscopy (SIMS) and Atomic Force Microscopy (AFM). - Research highlights: {yields} This work is reported the growth of AlxGa1-xAs/GaAs/AlxGa1-xAs heterostructures by a solid arsenic based MOCVD system. {yields} The results obtained with this system are comparable with those obtained with the traditional arsine based growth system. {yields} The main limitation of the alternative MOCVD system is related to the lack of monoatomic hydrogen on the growth surface that acts modifying the surface kinetics and enhancing the carbon incorporation. {yields} The experimental results indicate that it can be grown AlxGa1-xAs using elemental arsenic by MOCVD, which can be used to optoelectronic devices.

  13. Studies on exposure status of inhabitants to water-arsenic valence states in areas with endemic arsenism in the Datong basin in Shanxi

    Institute of Scientific and Technical Information of China (English)

    LI Jun; GAO Jianguo; CHENG Xiaotian; WANG Zhenghui; WEN Xinping; HAN Lingling; SANG Zhiping; ZHANG Jie; DUAN Hushun; LIANG Binfeng

    2007-01-01

    This study aimed to describe the distribution of water-arsenic(As)valence states and its relationship to areas with endemic arsenism in the Datong basin.Drinking water samples of patients with endemic arsenism and a control group were examined using hydride generation atomic fluorescence spectrometry(HG-AFS).We analyzed the data using SPSS10.0 for Windows.The As(Ⅲ)/As ratio was 52.1%in the water sample,exceeding the national standard of 0.05 mg/L.The As(Ⅲ)/As ratio significantly varied among the difierent stages in the disease-state groups,and with the control group(X2=22.4,P<0.01).The As(Ⅲ)/As(Ⅴ)ratio significantly varied in the four groups(X2=26.19,P<0.01),with a tendency to increase along with the seriousncss of the disease state.The most common type of drinking water arsenic valence state was As(Ⅲ)in the endemic diseaseareas.Endemic arsenism was positively correlated with As(Ⅲ).This led us to conclude that the fraction of each water-arsenic valence state should be studied when determining the arsenic content of drinking water.

  14. Arsenic Contamination in Food-chain: Transfer of Arsenic into Food Materials through Groundwater Irrigation

    OpenAIRE

    Huq, S.M. Imamul; Joardar, J.C.; Parvin, S.; Correll, Ray; Naidu, Ravi

    2006-01-01

    Arsenic contamination in groundwater in Bangladesh has become an additional concern vis-à-vis its use for irrigation purposes. Even if arsenic-safe drinking-water is assured, the question of irrigating soils with arsenic-laden groundwater will continue for years to come. Immediate attention should be given to assess the possibility of accumulating arsenic in soils through irrigation-water and its subsequent entry into the food-chain through various food crops and fodders. With this possibilit...

  15. Arsenic adsorption of lateritic soil, limestone powder, lime and fly ash on arsenic-contaminated soil

    OpenAIRE

    Wuthiphun, L.; Towatana, P.; Arrykul, S.; V. Chongsuvivatwong

    2007-01-01

    Arsenic adsorption efficiency of soil covering materials (lateritic soil, limestone powder, lime and fly ash) on arsenic-contaminated soil obtained from Ronpiboon District, Nakhon Sri Thammarat Province tosolve arsenic air pollution problem was investigated using batch experiments. The four types of the aforementioned soil covering materials were examined to determine their arsenic adsorption efficiency, equilibriumtime as well as adsorption isotherms.The results revealed that among soil cove...

  16. Generalized computational model for high-pressure metal hydrides with variable thermal properties

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Rokni, Masoud

    2015-01-01

    This study considers a detailed 1D fueling model applied to a metal hydride system, with Ti1.1CrMn as the absorbing alloy, to predict the weight fraction of the absorbed hydrogen and the solid bed temperature. Dependencies of thermal conductivity and specific heat capacity upon pressure...... and hydrogen content, respectively, are accounted for by interpolating experimental data. The effect of variable parameters on the critical metal hydride thickness is investigated and compared to results obtained from a constant-parameter analysis. Finally, the discrepancy in the metal hydride thickness value...

  17. Rapid Microwave Synthesis, Characterization and Reactivity of Lithium Nitride Hydride, Li4NH

    OpenAIRE

    Nuria Tapia-Ruiz; Natalie Sorbie; Nicolas Vaché; Hoang, Tuan K. A.; Gregory, Duncan H.

    2013-01-01

    Lithium nitride hydride, Li4NH, was synthesised from lithium nitride and lithium hydride over minute timescales, using microwave synthesis methods in the solid state for the first time. The structure of the microwave-synthesised powders was confirmed by powder X-ray diffraction [tetragonal space group I41/a; a = 4.8864(1) Å, c = 9.9183(2) Å] and the nitride hydride reacts with moist air under ambient conditions to produce lithium hydroxide and subsequently lithium carbonate. Li4NH undergoes n...

  18. Solid hydrides as hydrogen storage reservoirs; Hidruros solidos como acumuladores de hidrogeno

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.; Sanchez, C.; Friedrichs, O.; Ares, J. R.; Leardini, F.; Bodega, J.; Fernandez, J. F.

    2010-07-01

    Metal hydrides as hydrogen storage materials are briefly reviewed in this paper. Fundamental properties of metal-hydrogen (gas) system such as Pressure-Composition-Temperature (P-C-T) characteristics are discussed on the light of the metal-hydride thermodynamics. Attention is specially paid to light metal hydrides which might have application in the car and transport sector. The pros and cons of MgH{sub 2} as a light material are outlined. Researches in course oriented to improve the behaviour of MgH{sub 2} are presented. Finally, other very promising alternative materials such as Al compounds (alanates) or borohydrides as light hydrogen accumulators are also considered. (Author)

  19. Thermal decomposition kinetics of titanium hydride and Al alloy melt foaming process

    Institute of Scientific and Technical Information of China (English)

    YANG; Donghui; HE; Deping; YANG; Shangrun

    2004-01-01

    A temperature programmed decomposition (TPD) apparatus with metal tube structure, in which Ar is used as the carrier gas, is established and the TPD spectrum of titanium hydride is acquired. Using consulting table method (CTM), spectrum superposition method (SSM) and differential spectrum technique, TPD spectrum of titanium hydride is separated and a set of thermal decomposition kinetics equations are acquired. According to these equations, the relationship between decomposition quantity and time for titanium hydride at the temperature of 940 K is obtained and the result well coincides with the Al alloy melt foaming process.

  20. Proton beam production by a laser ion source with hydride target

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, M., E-mail: okamura@bnl.gov [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Stifler, C. [Engineering Physics Systems Department, Providence College, Providence, Rhode Island 02918 (United States); Palm, K. [Department of Physics, Cornell University, Ithaca, New York 14853 (United States); Steski, D.; Kanesue, T. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Ikeda, S. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa (Japan); Kumaki, M. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Research Institute for Science and Engineering, Waseda University, Tokyo (Japan)

    2016-02-15

    We studied proton beam production from a laser ion source using hydrogen rich target materials. In general, gas based species are not suitable for laser ion sources since formation of a dense laser target is difficult. In order to achieve reliable operation, we tested hydride targets using a sub nanosecond Q-switched Nd-YAG laser, which may help suppress target material consumption. We detected enough yields of protons from a titanium hydride target without degradation of beam current during the experiment. The combination of a sub nanosecond laser and compressed hydride target may provide stable proton beam.

  1. Analytical control of production of As, P, Si, B hydrides and the mixtures on their basis

    International Nuclear Information System (INIS)

    Highly sensitive and selective detectors which are in the basis of some analytical devices, such as chromatograph Tzvet 500G attachment POU-80, gigrometer Enisej gas analyzer Platon that permit to control the production of As, P, Si, B hydrides, are tested. The techniques of tetermination of constant gases, general carbon, moisture in the mixtures based on As, P, Si, B hydrides with diluting gases (H2, He, Ar) as well as hydrides in them and in the air of working premises, are suggested

  2. Studies on the differences of the arsenic's enrichment characteristics in kelps from different regions and varieties%不同区域与品种的海带中砷富集特征的差异

    Institute of Scientific and Technical Information of China (English)

    舒本胜; 王飞久; 尚德荣; 宁劲松; 孙修涛; 赵艳芳; 汪文俊; 李涛; 翟毓秀

    2011-01-01

    The experiments aim to study the enrichment regularity of inorganic arsenic and total arsenic in kelp by analyzing the variation of inorganic and total arsenic in kelps which are from different maritime regions and different species during their growth. The content of inorganic arsenic is detected by HPLC-AFS, while the content of the total arsenic is examined by hydride atomic fluorescence spectrophotometry in GB/T 5009.11 -2003. The results show that the enrichment in kelps of total arsenic displays an increase trend in growing season, whereas the content of inorganic arsenic is decreasing. The percentage of inorganic arsenic in total arsenic decreased from 1.36%-1.47% (March) to 0.41%-0.57% (July). The enrichment of inorganic and total arsenic varies from kelp to kelp even they are cultivated in the same maritime region, meanwhile, the same types of kelps have dramatically different contents of inorganic and total arsenic, which depends on the variety of maritime regions. Judging from the data, the contents of inorganic arsenic in all examined kelps are far below the MRL and will have no negative effects on food safety. The study provides relevant theory foundation for food safety and processing.%通过分析不同养殖海域、不同品种海带中无机砷和总砷含量在养殖期间的变化,研究海带中总砷及无机砷的富集规律.结果显示,在生长期内海带对总砷的富集呈增长趋势,而无机砷含量则逐渐降低,其占总砷的比例由3月份1.36%~1.47%下降到7月份的0.41% ~0.57%;同一海域、不同品种的海带对总砷和无机砷的富集具有差异性;同时期在不同养殖海域采收的同品种海带总砷和无机砷含量差异显著.基于监测数据对海带中的无机砷进行分析,所有海带样品中无机砷含量远低于现行食品卫生标准中的限量要求,不对食用安全性造成影响.

  3. Spectrophotometric determination of trace arsenic in water samples using a nanoparticle of ethyl violet with a molybdate-iodine tetrachloride complex as a probe for molybdoarsenate.

    Science.gov (United States)

    Morita, Keisuke; Kaneko, Emiko

    2006-11-15

    A new spectrophotometric method was developed for the determination of low ppb levels of arsenic in water. We found that Ethyl Violet with molybdate-iodine tetrachloride complex forms nanoparticles under acidic conditions, which provide a sensitive probe for molybdoarsenate. The nanoparticles form stable particles with a diameter micrometers in size in the presence of heteropolyacid, and the resulting particles give a purple color to the apparently homogeneous solution, the intensity of which depends on the arsenic concentration. The nanoparticle itself is unstable due to conversion of the dye to a colorless carbinol species under acidic conditions without heteropolyacid. Although triphenylmethane dyes have been the subject of a number of investigations, there do not appear to be any reports on the dye particles for trace determination. The calibration curve is linear up to 20 microg L-1 arsenic, and the detection limit is 0.5 microg L-1 (6.6 x 10(-9) mol L-1). The coefficient of variation for spectrophotometry at 10 microg L-1 is 5.8% (n = 8). Furthermore, it is possible to detect concentrations as low as 1 microg L-1 arsenic visually using this method. The interferences from phosphorus and silica were eliminated using an anion exchange column and sodium fluoride as a masking agent, respectively. The proposed method has been successfully applied to water samples in abandoned mine water, groundwater, and river water. There was good agreement between the results obtained by the proposed method and those by hydride generation atomic absorption spectrometry. Since this method is specific for As(V), it is applicable to the speciation of arsenic oxidation states. Our method has enormous practical potential for simple and field detection of arsenic, requiring no complex apparatus or skilled laboratory support. PMID:17105159

  4. Combined effects of DNA methyltransferase 1 and 3A polymorphisms and urinary total arsenic levels on the risk for clear cell renal cell carcinoma.

    Science.gov (United States)

    Yang, Shu-Mei; Huang, Chao-Yuan; Shiue, Horng-Sheng; Pu, Yeong-Shiau; Hsieh, Yi-Hsun; Chen, Wei-Jen; Lin, Ying-Chin; Hsueh, Yu-Mei

    2016-08-15

    Our previous study showed that high urinary total arsenic levels were associated with higher odds ratio (OR) for renal cell carcinoma (RCC). Single nucleotide polymorphisms (SNPs) of DNA methyltransferases (DNMTs) might influence DNMT enzyme activity associated with tumorigenesis. In this study, we investigated the association of five SNPs from DNMT1 (rs8101626 and rs2228611), DNMT3A (rs34048824 and rs1550117), and DNMT3B (rs1569686) with the risk of clear cell renal cell carcinoma (ccRCC). We also examined the combined effects of DNMT genotypes and urinary arsenic levels on ccRCC risk. We conducted a hospital-based case-control study, which included 293 subjects with ccRCC and 293 age- and gender-matched controls. The urinary arsenic species were determined by a high performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Genotypes were investigated using polymerase chain reaction and restriction fragment length polymorphism analyses. We observed that the DNMT1 rs8101626 G/G genotype was significantly associated with reduced odds ratio (OR) of ccRCC [OR=0.38, 95% confidence interval (CI) 0.14-0.99]. Subjects with concurrent DNMT1 rs8101626 A/A+A/G and DNMT3A rs34048824 T/T+T/C genotypes had significantly higher OR for ccRCC [OR=2.88, 95% CI 1.44-5.77]. Participants with the high-risk genotype of DNMT1 rs8101626 and DNMT3A rs34048824 with concurrently high urinary total arsenic levels had even higher OR of ccRCC in a dose-response manner. This is the first study to evaluate variant DNMT1 rs8101626 and DNMT3A rs34048824 genotypes that modify the arsenic-related ccRCC risk in a geographic area without significant arsenic exposure in Taiwan. PMID:27292127

  5. Outbreak of arsenic and toxaphene poisoning in Kenyan cattle. [Arsenic was detected in cattle dips

    Energy Technology Data Exchange (ETDEWEB)

    Maitai, C.K.; Kamau, J.A.; Gacuhi, D.M.; Njoroge, S.

    1975-02-15

    In a case of poisoning involving 70 cattle analysis of specimens obtained during post mortem examination showed that the toxic substances were arsenic and toxaphene. This was consistent with both the clinical and post mortem findings. Arsenic was detected in water from an abandoned cattle dip in the farm. Soil samples collected in the vicinity of the dip contained both arsenic and toxaphene.

  6. Method of arsenic removal from water

    Energy Technology Data Exchange (ETDEWEB)

    Gadgil, Ashok (El Cerrito, CA)

    2010-10-26

    A method for low-cost arsenic removal from drinking water using chemically prepared bottom ash pre-treated with ferrous sulfate and then sodium hydroxide. Deposits on the surface of particles of bottom ash form of activated iron adsorbent with a high affinity for arsenic. In laboratory tests, a miniscule 5 grams of pre-treated bottom ash was sufficient to remove the arsenic from 2 liters of 2400 ppb (parts per billion) arsenic-laden water to a level below 50 ppb (the present United States Environmental Protection Agency limit). By increasing the amount of pre-treated bottom ash, even lower levels of post-treatment arsenic are expected. It is further expected that this invention supplies a very low-cost solution to arsenic poisoning for large population segments.

  7. Arsenic--state of the art.

    Science.gov (United States)

    Landrigan, P J

    1981-01-01

    Approximately 1.5 million workers in the United States are exposed to arsenic. Occupational exposure is primarily by inhalation. NIOSH recommends that time-integrated exposure to arsenic in air not exceed 2 micrograms/m3. Recent exposure is accurately measured by urine assay; urine arsenic concentrations above 50 micrograms/liter indicate increased absorption. Hair assay is a semiquantitative index of past exposure. Toxicity is associated primarily with the trivalent (3+) form of arsenic. Acute poisoning is caused most commonly by contaminated food or drink; it is rarely occupational. Chronic intoxication is characterized by dermatitis, hyperpigmentation, keratoses, peripheral neuropathy (primarily sensory), irritation of the upper and lower respiratory tract, and occasionally by hepatic toxicity and peripheral vasculopathy (blackfoot disease). Arsenic is not carcinogenic in animal species, but is mutagenic in Syrian hamster cells. In man, arsenic is known definitely to cause cancer of skin, lung, and liver (angiosarcoma) and possibly to cause lymphoma.

  8. Arsenic stress after the Proterozoic glaciations

    OpenAIRE

    Ernest Chi Fru; Emma Arvestål; Nolwenn Callac; Abderrazak El Albani; Stephanos Kilias; Ariadne Argyraki; Martin Jakobsson

    2015-01-01

    Protection against arsenic damage in organisms positioned deep in the tree of life points to early evolutionary sensitization. Here, marine sedimentary records reveal a Proterozoic arsenic concentration patterned to glacial-interglacial ages. The low glacial and high interglacial sedimentary arsenic concentrations, suggest deteriorating habitable marine conditions may have coincided with atmospheric oxygen decline after ~2.1 billion years ago. A similar intensification of near continental mar...

  9. Presence of Arsenic in Commercial Beverages

    Directory of Open Access Journals (Sweden)

    Jason Roberge

    2009-01-01

    Full Text Available Problem statement: This study’s goal was to assess the arsenic concentration of various beverages and broths purchased from a local chain supermarket. A source of chronic arsenic exposure occurs via food and beverage consumption. Groundwater levels of total arsenic are regulated (-1 by the Environmental Protection Agency (EPA but few studies have examined arsenic concentrations in common beverages. Approach: In the initial analysis of 19 items, total arsenic concentration was assessed from a variety of fruit juices, sports drinks, sodas and broths. Items found to contain levels of total arsenic ≥5.0 µg L-1 were further evaluated. Additional analysis included purchasing multiple brands of items ≥5.0 µg L-1and analyzing them for total arsenic and chemical species of arsenic. Results: Among the beverages in the initial analysis, apple juice (10.79 µg L-1 and grape juice (49.87 µg L-1 contained the highest levels of total arsenic. Upon examination of items with As concentrations above 5.0 µg L-1, varying concentrations of total arsenic were found in apple cider (range: 5.41-15.27 µg L-1, apple juice (range: 10.67-22.35 µg L-1, baby fruit juice (range: 13.91-16.51 µg L-1 and grape juice (range: 17.69-47.59 µg L-1. Conclusion: Many commercially available juices contained concentrations of arsenic that were higher than the standard for total arsenic allowed in groundwater as set forth by the EPA. The concentration of As in these juices varied between and within brands. In general, those consuming apple and grape juices are the young and elderly and it is these populations that may be more vulnerable to over exposure of heavy metals.

  10. Arsenic Toxicity in Male Reproduction and Development

    OpenAIRE

    Kim, Yoon-Jae; Kim, Jong-Min

    2015-01-01

    Arsenic is a toxic metalloid that exists ubiquitously in the environment, and affects global health problems due to its carcinogenicity. In most populations, the main source of arsenic exposure is the drinking water. In drinking water, chronic exposure to arsenic is associated with increased risks of various cancers including those of skin, lung, bladder, and liver, as well as numerous other non-cancer diseases including gastrointestinal and cardiovascular diseases, diabetes, and neurologic a...

  11. Metal hydride hydrogen compression: recent advances and future prospects

    Science.gov (United States)

    Yartys, Volodymyr A.; Lototskyy, Mykhaylo; Linkov, Vladimir; Grant, David; Stuart, Alastair; Eriksen, Jon; Denys, Roman; Bowman, Robert C.

    2016-04-01

    Metal hydride (MH) thermal sorption compression is one of the more important applications of the MHs. The present paper reviews recent advances in the field based on the analysis of the fundamental principles of this technology. The performances when boosting hydrogen pressure, along with two- and three-step compression units, are analyzed. The paper includes also a theoretical modelling of a two-stage compressor aimed at describing the performance of the experimentally studied systems, their optimization and design of more advanced MH compressors. Business developments in the field are reviewed for the Norwegian company HYSTORSYS AS and the South African Institute for Advanced Materials Chemistry. Finally, future prospects are outlined presenting the role of the MH compression in the overall development of the hydrogen-driven energy systems. The work is based on the analysis of the development of the technology in Europe, USA and South Africa.

  12. Niche applications of metal hydrides and related thermal management issues

    Energy Technology Data Exchange (ETDEWEB)

    Lototskyy, M., E-mail: mlototskyy@uwc.ac.za [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Satya Sekhar, B. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Muthukumar, P. [Mechanical Department, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Linkov, V.; Pollet, B.G. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2015-10-05

    Highlights: • MH H{sub 2} storage, compression & heat management: developments/thermal management. • Thermodynamic criteria for proper selection of MH for different gas phase applications. • Factors influencing on H{sub 2} charge/discharge dynamic performance and energy efficiency. • The improvement of MH heat transfer characteristics is crucial. • Ways of improvement of heat transfer in the MH systems. - Abstract: This short review highlights and discusses the recent developments and thermal management issues related to metal hydride (MH) systems for hydrogen storage, hydrogen compression and heat management (refrigeration, pump and upgrade, etc.). Special attention is paid to aligning the system features with the requirements of the specific application. The considered system features include the MH material, the MH bed on the basis of its corresponding MH container, as well as the layout of the integrated system.

  13. Crystal structure of the superconducting phase of sulfur hydride

    Science.gov (United States)

    Einaga, Mari; Sakata, Masafumi; Ishikawa, Takahiro; Shimizu, Katsuya; Eremets, Mikhail I.; Drozdov, Alexander P.; Troyan, Ivan A.; Hirao, Naohisa; Ohishi, Yasuo

    2016-09-01

    A superconducting critical temperature above 200 K has recently been discovered in H2S (or D2S) under high hydrostatic pressure. These measurements were interpreted in terms of a decomposition of these materials into elemental sulfur and a hydrogen-rich hydride that is responsible for the superconductivity, although direct experimental evidence for this mechanism has so far been lacking. Here we report the crystal structure of the superconducting phase of hydrogen sulfide (and deuterium sulfide) in the normal and superconducting states obtained by means of synchrotron X-ray diffraction measurements, combined with electrical resistance measurements at both room and low temperatures. We find that the superconducting phase is mostly in good agreement with the theoretically predicted body-centred cubic (bcc) structure for H3S. The presence of elemental sulfur is also manifest in the X-ray diffraction patterns, thus proving the decomposition mechanism of H2S to H3S + S under pressure.

  14. Pressure-induced transformations of molecular boron hydride

    CERN Document Server

    Nakano, S; Gregoryanz, E A; Goncharov, A F; Mao Ho Kwang

    2002-01-01

    Decaborane, a molecular boron hydride, was compressed to 131 GPa at room temperature to explore possible non-molecular phases in this system and their physical properties. Decaborane changed its colour from transparent yellow to orange/red above 50 GPa and then to black above 100 GPa, suggesting some transformations. Raman scattering and infrared (IR) absorption spectroscopy reveal significant structural changes. Above 100 GPa, B-B skeletal, B-H and B-H-B Raman/IR peaks gradually disappeared, which implies a transformation into a non-molecular phase in which conventional borane-type bonding is lost. The optical band gap of the material at 100 GPa was estimated to be about 1.0 eV.

  15. Niche applications of metal hydrides and related thermal management issues

    International Nuclear Information System (INIS)

    Highlights: • MH H2 storage, compression & heat management: developments/thermal management. • Thermodynamic criteria for proper selection of MH for different gas phase applications. • Factors influencing on H2 charge/discharge dynamic performance and energy efficiency. • The improvement of MH heat transfer characteristics is crucial. • Ways of improvement of heat transfer in the MH systems. - Abstract: This short review highlights and discusses the recent developments and thermal management issues related to metal hydride (MH) systems for hydrogen storage, hydrogen compression and heat management (refrigeration, pump and upgrade, etc.). Special attention is paid to aligning the system features with the requirements of the specific application. The considered system features include the MH material, the MH bed on the basis of its corresponding MH container, as well as the layout of the integrated system

  16. Final report for the DOE Metal Hydride Center of Excellence.

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jay O.; Klebanoff, Leonard E.

    2012-01-01

    This report summarizes the R&D activities within the U.S. Department of Energy Metal Hydride Center of Excellence (MHCoE) from March 2005 to June 2010. The purpose of the MHCoE has been to conduct highly collaborative and multi-disciplinary applied R&D to develop new reversible hydrogen storage materials that meet or exceed DOE 2010 and 2015 system goals for hydrogen storage materials. The MHCoE combines three broad areas: mechanisms and modeling (which provide a theoretically driven basis for pursuing new materials), materials development (in which new materials are synthesized and characterized) and system design and engineering (which allow these new materials to be realized as practical automotive hydrogen storage systems). This Final Report summarizes the organization and execution of the 5-year research program to develop practical hydrogen storage materials for light duty vehicles. Major results from the MHCoE are summarized, along with suggestions for future research areas.

  17. Modelling zirconium hydrides using the special quasirandom structure approach

    KAUST Repository

    Wang, Hao

    2013-01-01

    The study of the structure and properties of zirconium hydrides is important for understanding the embrittlement of zirconium alloys used as cladding in light water nuclear reactors. Simulation of the defect processes is complicated due to the random distribution of the hydrogen atoms. We propose the use of the special quasirandom structure approach as a computationally efficient way to describe this random distribution. We have generated six special quasirandom structure cells based on face centered cubic and face centered tetragonal unit cells to describe ZrH2-x (x = 0.25-0.5). Using density functional theory calculations we investigate the mechanical properties, stability, and electronic structure of the alloys. © the Owner Societies 2013.

  18. Delayed hydride cracking: theoretical model testing to predict cracking velocity

    International Nuclear Information System (INIS)

    Pressure tubes from Candu nuclear reactors as any other component manufactured with Zr alloys are prone to delayed hydride cracking. That is why it is important to be able to predict the cracking velocity during the component lifetime from parameters easy to be measured, such as: hydrogen concentration, mechanical and microstructural properties. Two of the theoretical models reported in literature to calculate the DHC velocity were chosen and combined, and using the appropriate variables allowed a comparison with experimental results of samples from Zr-2.5 Nb tubes with different mechanical and structural properties. In addition, velocities measured by other authors in irradiated materials could be reproduced using the model described above. (author)

  19. Noble-gas hydrides: new chemistry at low temperatures.

    Science.gov (United States)

    Khriachtchev, Leonid; Räsänen, Markku; Gerber, R Benny

    2009-01-20

    Noble-gas chemistry has been undergoing a renaissance in recent years, due in large part to noble-gas hydrides, HNgY, where Ng = noble-gas atom and Y = electronegative fragment. These molecules are exceptional because of their relatively weak bonding and large dipole moments, which lead to strongly enhanced effects of the environment, complexation, and reactions. In this Account, we discuss the matrix-isolation synthesis of noble-gas hydrides, their spectroscopic and structural properties, and their stabilities.This family of species was discovered in 1995 and now has 23 members that are prepared in noble-gas matrices (HXeBr, HKrCl, HXeH, HXeOH, HXeO, etc.). The preparations of the first neutral argon molecule, HArF, and halogen-free organic noble-gas molecules (HXeCCH, HXeCC, HKrCCH, etc.) are important highlights of the field. These molecules are formed by the neutral H + Ng + Y channel. The first addition reaction involving HNgY molecules was HXeCC + Xe + H --> HXeCCXeH, and this led to the first hydride with two noble-gas atoms (recently extended by HXeOXeH). The experimental synthesis of HNgY molecules starts with production of H and Y fragments in solid noble gas via the UV photolysis of suitable precursors. The HNgY molecules mainly form upon thermal mobilization of the fragments.One of the unusual properties of these molecules is the hindered rotation of some HNgY molecules in solid matrices; this has been theoretically modeled. HNgY molecules also have unusual solvation effects, and the H-Xe stretching mode shifts to higher frequencies (up to about 150 cm-1) upon interaction with other species.The noble hydrides have a new bonding motif: HNgY molecules can be represented in the form (H-Ng)+Y-, where (H-Ng)+ is mainly covalent, whereas the interaction between (HNg)+ and Y- is predominantly ionic. The HNgY molecules are highly metastable species representing high-energy materials. The decomposition process HNgY --> Ng + HY is always strongly exoergic

  20. Hydride Formation in Neutron Irradiated Material Under In Reactor Conditions

    International Nuclear Information System (INIS)

    The present is a brief summary of the three reports completed within the framework of the SPAR III project. The following is a resume of our aims, techniques used to achieve the objectives and conclusions attained under the guiding thread of the hydride formation in neutron irradiated zirconium alloys and other reactor in operating conditions. As is it known, under reactor operating conditions zirconium components go through transformations which affect their original microstructural and thermodynamical properties. Both concerns are starting points of many research lines for the zirconium alloys used in the nuclear power reactors. Regarding microstructural transformations, one of the most important topics is the phase stability of these alloys. To cite a well-known case, second phase particles of zircaloy-4 shown to be unstable under neutron radiation. Since such phases play a role in the corrosion rate control, this instability became a problem for high burnup fuel claddings design. Similar observations can be made about the β−Zr phase in the Zr-2.5Nb CANDU pressure tubes alloy. On the other hand, there are issues directly involved with thermodynamics, e.g., hydrogen behaviour and its role in the degradation processes of fuel assemblies and other zirconium alloys components, which showed to be affected by neutron radiation. Finally, applied stresses and thermal cycling are part of these operating conditions, which can be simulated performing experiments in situ which allows testing hydrogen solubility behaviour and hydride reorientation. In the context described above, the research topics proposed to SPAR III were aimed to improve the knowledge of these degradation processes. In this scheme, zircaloy-4 which remained more than ten years at full power operation and virgin unirradiated zirconium alloys were suited by the more improved micro analytical techniques to characterize microstructural transformations cited above

  1. Speciation of arsenic of liquid and gaseous emissions from soil in a microcosmos experiment by liquid and gas chromatography with inductively coupled plasma mass spectrometer (ICP-MS) detection

    Energy Technology Data Exchange (ETDEWEB)

    Prohaska, T.; Stingeder, G. [University of Agricultural Sciences - BOKU Wien (Austria). Inst. of Chemistry; Pfeffer, M.; Tulipan, M.; Mentler, A.; Wenzel, W.W. [Vienna University of Agricultural Sciences - BOKU Wien (Austria). Inst. of Soil Science

    1999-07-01

    Gas chromatography and high-performance liquid chromatography coupled to a double focusing sectorfield ICP-MS as sensitive element specific detector are used for the speciation of arsenic of liquid and gaseous emissions from soil samples, which were equilibrated in a microcosmos experiment. Speciation of liquid samples was performed by HPLC and hydride generation was used as introduction system to ICP-MS. An online prereduction step was introduced to enhance the sensitivity for As(V). A home-built and laboratory-ready transfer line from GC to ICP-MS is presented and quantification of As in gaseous emissions was performed by external calibration via hydride generation. The microcosmos experiment revealed only low production rates of organoarsenic compounds and reflected a limited capability of the biovolatilization experiment for the simulation of natural systems. (orig.) With 5 figs., 5 tabs., 29 refs.

  2. Joint Effect of Urinary Total Arsenic Level and VEGF-A Genetic Polymorphisms on the Recurrence of Renal Cell Carcinoma.

    Directory of Open Access Journals (Sweden)

    Shu-Mei Yang

    Full Text Available The results of our previous study suggested that high urinary total arsenic levels were associated with an increased risk of renal cell carcinoma (RCC. Germline genetic polymorphisms might also affect cancer risk and clinical outcomes. Vascular endothelial growth factor (VEGF plays an important role in vasculogenesis and angiogenesis, but the combined effect of these factors on RCC remains unclear. In this study, we explored the association between the VEGF-A -2578C>A, -1498T>C, -1154G>A, -634G>C, and +936C>T gene polymorphisms and RCC. We also evaluated the combined effects of the VEGF-A haplotypes and urinary total arsenic levels on the prognosis of RCC. This case-control study was conducted with 191 RCC patients who were diagnosed with renal tumors on the basis of image-guided biopsy or surgical resections. An additional 376 age- and gender-matched controls were recruited. Concentrations of urinary arsenic species were determined by a high performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Genotyping was investigated using fluorescent-based TaqMan allelic discrimination. We observed no significant associations between VEGF-A haplotypes and RCC risk. However, the VEGF-A ACGG haplotype from VEGF-A -2578, -1498, -1154, and -634 was significantly associated with an increased recurrence of RCC (OR = 3.34, 95% CI = 1.03-10.91. Urinary total arsenic level was significantly associated with the risk of RCC in a dose-response manner, but it was not related to the recurrence of RCC. The combination of high urinary total arsenic level and VEGF-A risk haplotypes affected the OR of RCC recurrence in a dose-response manner. This is the first study to show that joint effect of high urinary total arsenic and VEGF-A risk haplotypes may influence the risk of RCC recurrence in humans who live in an area without obvious arsenic exposure.

  3. Stability of toxic arsenic species and arsenosugars found in the dry alga Hijiki and its water extracts.

    Science.gov (United States)

    García-Salgado, Sara; Quijano, M Ángeles

    2014-10-01

    The achievement of reliable results in speciation analysis requires not only sensitive techniques but also sureness of species stability. Therefore, it is necessary to carry out stability studies because it is important to know with absolute certainty that there is not any species transformation during sample treatment and/or storage. Although several procedures have been recommended for the preservation of species integrity, there is no general agreement, as arsenic species stability depends on the sample matrix, the concentration level and the sample treatment procedure, so it is necessary to assess the arsenic species stability for each case. Thus, the present paper reports the stability tests of arsenic species carried out on the commercially available edible alga Hijiki (Hizikia fusiformis), from Japan, in both the dry sample and its water extracts, which were stored in amber glass and polystyrene containers at -18 and +4°C in the dark. Extractions were carried out with deionized water by microwave-assisted extraction, at a temperature of 90°C and three extraction steps of 5 min each, whereas arsenic speciation analysis was performed by anion exchange high performance liquid chromatography-photo-oxidation-hydride generation-atomic fluorescence spectrometry. The results obtained for the dry alga showed that the arsenic species present in it (arsenate (As(V)), dimethylarsinic acid (DMA) and the arsenosugars glycerol (Gly-sug), phosphate (PO4-sug), sulfonate (SO3-sug) and sulfate (SO4-sug)) were stable for at least 12 months when the sample was stored in polystyrene containers at +20°C in the dark. Regarding water extracts, the best storage conditions consisted of the use of polystyrene containers and a temperature of +4°C, for a maximum storage time of seven days. Therefore, the immediate analysis of Hijiki water extracts would not be necessary, and they could be stored for one week before analysis, ensuring arsenic species stability. This information about

  4. Certain cases of poisoning by arsenic

    Energy Technology Data Exchange (ETDEWEB)

    Cristol, P.; Fourcade, J.; Ravoire, J.; Bezenech, C.

    1939-05-01

    Cases of acute and chronic poisoning by arsenic are reported. Diffuse pains, angor, edema of the limbs and genitals, complicated by heptic insufficiency and chronic bronchitis were determined in a subject having lived near an industrial plant processing arseniferous ores for several years. The plant emitted several hundred kg of finely dispersed arsenic oxide daily which settled on forage and vegetables. Symptoms of poisoning by arsenic were also detected in cattle in the same area. The installation of Cottrell type dust separators has helped to suppress the arsenic oxide emissions.

  5. Arsenic-bound excitons in diamond

    Science.gov (United States)

    Barjon, J.; Jomard, F.; Morata, S.

    2014-01-01

    A set of new excitonic recombinations is observed in arsenic-implanted diamond. It is composed of two groups of emissions at 5.355/5.361 eV and at 5.215/5.220/5.227 eV. They are respectively attributed to the no-phonon and transverse-optical phonon-assisted recombinations of excitons bound to neutral arsenic donors. From the Haynes rule, an ionization energy of 0.41 eV is deduced for arsenic in diamond, which shows that arsenic is a shallower donor than phosphorus (0.6 eV), in agreement with theory.

  6. Industrial contributions of arsenic to the environment.

    Science.gov (United States)

    Nelson, K W

    1977-08-01

    Arsenic is present in all copper, lead, and zinc sulfide ores and is carried along with those metals in the mining, milling and concentrating process. Separation, final concentration and refining of by-product arsenic as the trioxide is achieved at smelters. Arsenic is the essential consistent element of many compounds important and widely used in agriculture and wood preservation. Lesser amounts are used in metal alloys, glass-making, and feed additives. There is no significant recycling. Current levels of arsenic emissions to the atmosphere from smelters and power plants and ambient air concentrations are given as data of greatest environmental interest. PMID:908308

  7. Arsenic and antimony transporters in eukaryotes.

    Science.gov (United States)

    Maciaszczyk-Dziubinska, Ewa; Wawrzycka, Donata; Wysocki, Robert

    2012-01-01

    Arsenic and antimony are toxic metalloids, naturally present in the environment and all organisms have developed pathways for their detoxification. The most effective metalloid tolerance systems in eukaryotes include downregulation of metalloid uptake, efflux out of the cell, and complexation with phytochelatin or glutathione followed by sequestration into the vacuole. Understanding of arsenic and antimony transport system is of high importance due to the increasing usage of arsenic-based drugs in the treatment of certain types of cancer and diseases caused by protozoan parasites as well as for the development of bio- and phytoremediation strategies for metalloid polluted areas. However, in contrast to prokaryotes, the knowledge about specific transporters of arsenic and antimony and the mechanisms of metalloid transport in eukaryotes has been very limited for a long time. Here, we review the recent advances in understanding of arsenic and antimony transport pathways in eukaryotes, including a dual role of aquaglyceroporins in uptake and efflux of metalloids, elucidation of arsenic transport mechanism by the yeast Acr3 transporter and its role in arsenic hyperaccumulation in ferns, identification of vacuolar transporters of arsenic-phytochelatin complexes in plants and forms of arsenic substrates recognized by mammalian ABC transporters.

  8. Acute arsenic poisoning in two siblings.

    Science.gov (United States)

    Lai, Melisa W; Boyer, Edward W; Kleinman, Monica E; Rodig, Nancy M; Ewald, Michele Burns

    2005-07-01

    We report a case series of acute arsenic poisoning of 2 siblings, a 4-month-old male infant and his 2-year-old sister. Each child ingested solubilized inorganic arsenic from an outdated pesticide that was misidentified as spring water. The 4-month-old child ingested a dose of arsenic that was lethal despite extraordinary attempts at arsenic removal, including chelation therapy, extracorporeal membrane oxygenation, exchange transfusion, and hemodialysis. The 2-year-old fared well with conventional therapy. PMID:15995066

  9. XAS Studies of Arsenic in the Environment

    International Nuclear Information System (INIS)

    Arsenic is present in low concentrations in much of the Earth's crust and changes in its speciation are vital to understanding its transport and toxicity in the environment. We have used X-ray absorption spectroscopy to investigate the coordination sites of arsenic in a wide variety of samples, including soil and earthworm tissues from arsenic-contaminated land, and human hair and nail samples from people exposed to arsenic in Cambodia. Our results confirm the effectiveness of using X-ray absorption near edge structure (XANES) and X-ray absorption fine structure (EXAFS) spectroscopy to determine speciation changes in environmental samples

  10. Arsenic in the soils of Zimapan, Mexico

    International Nuclear Information System (INIS)

    Arsenic concentrations of 73 soil samples collected in the semi-arid Zimapan Valley range from 4 to 14 700 mg As kg-1. Soil arsenic concentrations decrease with distance from mines and tailings and slag heaps and exceed 400 mg kg-1 only within 500 m of these arsenic sources. Soil arsenic concentrations correlate positively with Cu, Pb, and Zn concentrations, suggesting a strong association with ore minerals known to exist in the region. Some As was associated with Fe and Mn oxyhydroxides, this association is less for contaminated than for uncontaminated samples. Very little As was found in the mobile water-soluble or exchangeable fractions. The soils are not arsenic contaminated at depths greater than 100 cm below the surface. Although much of the arsenic in the soils is associated with relatively immobile solid phases, this represents a long-term source of arsenic to the environment. -- Much of the arsenic is relatively immobile but presents long-term source of arsenic

  11. Heat transfer characteristics of the metal hydride vessel based on the plate-fin type heat exchanger

    Science.gov (United States)

    Oi, Tsutomu; Maki, Kohei; Sakaki, Yoshinori

    Heat transfer characteristics of the metal hydride vessel based on the plate-fin type heat exchanger were investigated. Metal hydride beds were filled with AB 2 type hydrogen-storage alloy's particles, Ti 0.42Zr 0.58Cr 0.78Fe 0.57Ni 0.2Mn 0.39Cu 0.03, with a storage capacity of 0.92 wt.%. Heat transfer model in the metal hydride bed based on the heat transfer mechanism for packed bed proposed by Kunii and co-workers is presented. The time-dependent hydrogen absorption/desorption rate and pressure in the metal hydride vessel calculated by the model were compared with the experimental results. During the hydriding, calculated hydrogen absorption rates agreed with measured ones. Calculated thermal equilibrium hydrogen pressures were slightly lower than the measured hydrogen pressures at the inlet of metal hydride vessel. Taking account of the pressure gradient between the inlet of metal hydride vessel and the metal hydride bed, it is considered that this discrepancy is reasonable. During the dehydriding, there were big differences between the calculated hydrogen desorption rates and measured ones. As calculated hydrogen desorption rates were lower than measured ones, there were big differences between the calculated thermal equilibrium hydrogen pressures and the measured hydrogen pressures at the inlet of metal hydride vessel. It is considered that those differences are due to the differences of the heat transfer characteristics such as thermal conductivity of metal hydride particles and porosity between the assumed and actual ones. It is important to obtain the heat transfer characteristics such as thermal conductivity of metal hydride particles and porosity both during the hydriding and dehydriding to design a metal hydride vessel.

  12. Wild plants as tools for the remediation of abandoned mining sites with a high arsenic content

    Science.gov (United States)

    Martínez-Lopez, Salvadora; Martínez-Sanchez, MJose; Perez-Sirvent, Carmen; Martínez, Lucia B.; Bech, Jaume

    2014-05-01

    The aim of this study was to assess the environmental risk posed by arsenic when new vegetation types are introduced, analyzing the transfer of arsenic in different plant species that grow spontaneously in mining areas of SE Spain (Sierra Minera of Cartagena), and the contribution of such plants to the environmental risk represented by their ingestion by animals living in the same ecosystems. When dealing with remediation projects in zones affected by mining activities, the risk posed by the ingestion of the plants by fauna is often forgotten. To study the transfer to the trophic chain, two mammals, sheep and vole, were selected. The risk analysis was centered in the contribution of these natural plants to the ingestion calculated. For this study, 21 vegetal species naturally growing in the soils were collected from the Sierra Minera. The vegetal material studied is clearly associated with the Mediterranean Region (S.E. of Spain) and the plant species collected are endemisms and plants characteristic of the zone. Physico-chemical properties were obtained by means of the usual procedures. To determine the arsenic content, the soil samples and plant materials were digested in a microwave system and the arsenic concentration was determined using atomic fluorescence spectrometry with an automated continuous flow hydride generation system. A semiquantitative estimation of the mineralogical composition of the samples was made by X Ray Diffraction analysis. The soils were classified into three groups: Low (group 1) (7-35 mg/kg) medium (group 2) (35-327 mg/kg) and high (group 3) (> 327 mg/kg), according to their As content. The mineralogy and As content of the soils studied depends on the materials related with mining activity. The descriptive statistical analysis of the population of plants studied showed the As range in roots to be 0.31-150 mg/kg while leaf concentrations were lower (0.21-83.4 mg/kg). The potential risk of As entering the food chain through of the plant

  13. Status of groundwater arsenic contamination in Bangladesh: a 14-year study report.

    Science.gov (United States)

    Chakraborti, Dipankar; Rahman, Mohammad Mahmudur; Das, Bhaskar; Murrill, Matthew; Dey, Sankar; Chandra Mukherjee, Subhas; Dhar, Ratan Kumar; Biswas, Bhajan Kumar; Chowdhury, Uttam Kumar; Roy, Shibtosh; Sorif, Shahariar; Selim, Mohammad; Rahman, Mahmuder; Quamruzzaman, Quazi

    2010-11-01

    Since 1996, 52,202 water samples from hand tubewells were analyzed for arsenic (As) by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) from all 64 districts of Bangladesh; 27.2% and 42.1% of the tubewells had As above 50 and 10 μg/l, respectively; 7.5% contained As above 300 μg/l, the concentration predicting overt arsenical skin lesions. The groundwater of 50 districts contained As above the Bangladesh standard for As in drinking water (50 μg/l), and 59 districts had As above the WHO guideline value (10 μg/l). Water analyses from the four principal geomorphological regions of Bangladesh showed that hand tubewells of the Tableland and Hill tract regions are primarily free from As contamination, while the Flood plain and Deltaic region, including the Coastal region, are highly As-contaminated. Arsenic concentration was usually observed to decrease with increasing tubewell depth; however, 16% of tubewells deeper than 100 m, which is often considered to be a safe depth, contained As above 50 μg/l. In tubewells deeper than 350 m, As >50 μg/l has not been found. The estimated number of tubewells in 50 As-affected districts was 4.3 million. Based on the analysis of 52,202 hand tubewell water samples during the last 14 years, we estimate that around 36 million and 22 million people could be drinking As-contaminated water above 10 and 50 μg/l, respectively. However for roughly the last 5 years due to mitigation efforts by the government, non-governmental organizations and international aid agencies, many individuals living in these contaminated areas have been drinking As-safe water. From 50 contaminated districts with tubewell As concentrations >50 μg/l, 52% of sampled hand tubewells contained As poisoning and to prevent this disaster from continuing to plague individuals in the future.

  14. Catalytic Radical Reduction in Aqueous Solution by a Ruthenium Hydride Intermediate.

    Science.gov (United States)

    Htet, Yamin; Tennyson, Andrew G

    2016-07-18

    Some manganese complexes can catalyze both antioxidant and pro-oxidant reactions, whereby the disparate reactivity modes are determined by the catalyst environment and afford distinct therapeutic effects. We recently reported the reduction of radicals in buffered aqueous solution catalyzed by a ruthenium complex with biologically relevant non-tertiary alcohols as terminal reductants. Mechanistic evidence is presented, indicating that this catalytic radical reduction is achieved by a Ru-hydride intermediate formed by β-hydride elimination from a Ru-alkoxide species. A similar mechanism and Ru-hydride intermediate was previously reported to kill cancer cells with catalytic pro-oxidant effects. Therefore, our demonstration of catalytic antioxidant effects by the same type of intermediate reveals new potential therapeutic strategies and applications for catalytic systems that form Ru-hydride intermediates. PMID:27254303

  15. In situ probing of surface hydrides on hydrogenated amorphous silicon using attenuated total reflection infrared spectroscopy

    CERN Document Server

    Kessels, W M M; Sanden, M C M; Aydil, E S

    2002-01-01

    An in situ method based on attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) is presented for detecting surface silicon hydrides on plasma deposited hydrogenated amorphous silicon (a-Si:H) films and for determining their surface concentrations. Surface silicon hydrides are desorbed by exposing the a-Si:H films to low energy ions from a low density Ar plasma and by comparing the infrared spectrum before and after this low energy ion bombardment, the absorptions by surface hydrides can sensitively be separated from absorptions by bulk hydrides incorporated into the film. An experimental comparison with other methods that utilize isotope exchange of the surface hydrogen with deuterium showed good agreement and the advantages and disadvantages of the different methods are discussed. Furthermore, the determination of the composition of the surface hydrogen bondings on the basis of the literature data on hydrogenated crystalline silicon surfaces is presented, and quantification of the h...

  16. Hydride precipitation kinetics in Zircaloy-4 studied using synchrotron X-ray diffraction

    Science.gov (United States)

    Courty, Olivier F.; Motta, Arthur T.; Piotrowski, Christopher J.; Almer, Jonathan D.

    2015-06-01

    As a result of in-reactor corrosion during operation in nuclear reactors, hydrogen can enter the zirconium fuel cladding and precipitate as brittle hydride particles, which may reduce cladding ductility. Dissolved hydrogen responds to temperature gradients, resulting in transport and precipitation into cold spots so that the distribution of hydrides in the cladding is inhomogeneous. The hydrogen precipitation kinetics plays a strong role in the spatial distribution of the hydrides in the cladding. The precipitation rate is normally described as proportional to the supersaturation of hydrogen in solid solution. The proportionality constant, α2, for hydride precipitation in Zircaloy-4 is measured directly using in situ synchrotron X-Ray diffraction, at different temperatures and with three different initial hydrogen concentrations. The results validate the linear approximation of the phenomenological model and a near constant value of α2 = 4.5 × 10-4 s-1 was determined for the temperature range studied.

  17. The microstructure and hydriding characteristics of high temperature aged U-13 at.%Nb alloy

    Science.gov (United States)

    Ji, Hefei; Shi, Peng; Li, Ruiwen; Jiang, Chunli; Yang, Jiangrong; Hu, Guichao

    2015-09-01

    Niobium as alloying element significantly improves physical and chemical properties of metallic uranium, exhibiting great application potential in uranium alloy materials. The corrosion resistance performance as well as the internal alloy phase structure of uranium-niobium alloy is closely related to aging processes. Microstructure and hydriding characteristics of the 400 °C/9 h + 500 °C/2 h aged uranium-13 at.% niobium alloys (U-13 at.%Nb) were investigated from the point of view of relationship between the microstructure and growth of the hydriding areas. The microstructure, morphology and composition of the alloy phases before and after the hydriding were well characterized by the laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Experimental results indicated that the hydrogen preferentially reacted with the Nb-depleted phase α-like-U to form monolithic β-UH3Nbx, and the alloy microstructure played an important role in hydride growth.

  18. The two steps thermal decomposition of titanium hydride and two steps foaming of Al alloy

    Institute of Scientific and Technical Information of China (English)

    SHANG Jintang; HE Deping

    2005-01-01

    Two steps foaming (TSF) technique was proposed to prepare shaped Al alloy foam. Based on the thermal decomposition kinetics equation of titanium hydride, the relationship between two steps thermal decomposition kinetics of titanium hydride and two steps foaming Al alloy melt was studied. Two steps thermal decomposition curve of titanium hydride under increasing and constant temperature was calculated respectively. The hydrogen mass needed in the second foaming step was also calculated. Results showed that the hydrogen mass of the second thermal decomposition of titanium hydride is enough for the second foaming step in the condition of as-received Al melt foaming. Experimental and theoretical results indicate that two steps foaming technique can be used to prepare Al alloy foam with high porosity, shaped components and sandwich with Al alloy foam core.

  19. Hyphenating multisyringe flow injection lab-on-valve analysis with atomic fluorescence spectrometry for on-line bead-injection preconcentration and determination of trace levels of hydride-forming elements in environmental samples

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald;

    2006-01-01

    In this work, the third generation of flow injection analysis, that is, the so-called micro-Lab-on-Valve (μLOV) approach, is proposed for the first time for the separation, preconcentration and monitoring of metalloids as hyphenated with atomic fluorescence spectrometry (AFS). This was made...... feasible by interfacing the micromachined LOV-module with AFS by a multisyringe flowing stream network for on-line post column derivatization of the eluate aimed at the generation of hydride species. The potential of this new hyphenated technique for environmental assays was ascertained via...... quantified by AFS. The flow system facilitates on-column reduction of the retained arsenic with no need for application of programmable stopped-flow. Yet, the high concentration of reductant and extreme pH conditions for elution hinder the sorbent to be re-used due to the gradual deactivation...

  20. The formation and characteristics of hydride blisters in c.w. Zircaloy-2 pressure tubes

    International Nuclear Information System (INIS)

    Under the auspices of the IAEA, a consultants' meeting was arranged in Vienna, 1994 July 25-29, at which a Canadian delegation, consisting of AECL and Ontario Hydro Technologies personnel, presented information on their knowledge of the behaviour of hydride blisters in Zircaloy-2 pressure tubes. This document contains the 10 papers presented by the Canadian delegation to the meeting. It is believed that they represent a good reference document on hydride blister phenomena

  1. Direct hydride derivatization of methyl- and ethylmercury chlorides in aqueous solution with KBH4

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A convenient hydride derivatization procedure of methyl-and ethylmercury chlorides to volatile hydrides was reported. In sealed vials methylmercury and ethylmercury compounds in acidic aqueous solutions were converted into their volatile forms by the reaction with potassium tetrahydroborate(KBH4) and elvolved to the headspace of the vials. The gaseous analytes in the headspace were extracted and concentrated by solid phase microextraction(SPME) and injected into gas chromatography (GC) for separation and identified by mass selective detector(MS).

  2. Dehydrogenation in lithium borohydride/conventional metal hydride composite based on a mutual catalysis

    DEFF Research Database (Denmark)

    Yu, X.B.; Shi, Qing; Vegge, Tejs;

    2009-01-01

    The dehydrogenation of LiBH4 ball-milled with hydrogenated 40Ti–15Mn–15Cr–30V alloy was investigated. It was found that there is a mutual catalysis between the two hydrides, lowering the temperature of hydrogen release from both hydrides. In the case of 1h milled LiBH4/40Ti–15Mn–15Cr–30V with a...

  3. The thermodynamics of hydride precipitation: the importance of entropy, enthalpy and disorder

    OpenAIRE

    Lumley, S. C.; Grimes, R. W.; Murphy, S. T.; Burr, P. A.; Chroneos, A.; Chard-Tucke, P. R.; Wenman, M. R.

    2014-01-01

    The thermodynamics of H/{\\alpha}-Zr solid solution and zirconium hydride phases were studied using density functional theory. Disorder in {\\zeta}, {\\gamma} and {\\delta} hydrides and solid solutions were modelled using a statistically significant number of randomly generated structures in combination with special quasi-random structures and solid solutions with a range of concentrations. This is used in conjunction with a calculation of thermodynamic parameters of the system, including the tem...

  4. [Tracing for arsenic exposure--a differentiation of arsenic compounds is essential for the health assessment].

    Science.gov (United States)

    Weistenhöfer, Wobbeke; Ochsmann, Elke; Drexler, Hans; Göen, Thomas; Klotz, Katrin

    2016-01-01

    Arsenic is ubiquitous and harmful to health in occupation and environment. Arsenic exposure is measured through analysis of arsenic compounds in urine. The identification of several arsenic species is necessary to understand the hazardous potential of the arsenic compounds which differ highly in their toxicity. To estimate the extent of an occupational exposure to arsenic, arsenic species were evaluated for the first time by the working group "Setting of Threshold Limit Values in Biological Material" of the DFG Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area and Biologische Arbeitsstoffreferenzwerte (BAR) of 0.5 μg / L urine for arsenic (III), 0.5 μg / L urine for arsenic (V), 2 μg / L urine for monomethylarsonic acid (MMA) and 10 μg / L urine for dimethylarsinic acid (DMA) were set. If the reference value for total arsenic is exceeded, a further differentiation of arsenic species now enables to estimate the individual health risks taking into account special influences such as seafood consumption.

  5. Arsenic (+3 oxidation state) methyltransferase and the inorganic arsenic methylation phenotype

    International Nuclear Information System (INIS)

    Inorganic arsenic is enzymatically methylated; hence, its ingestion results in exposure to the parent compound and various methylated arsenicals. Both experimental and epidemiological evidences suggest that some of the adverse health effects associated with chronic exposure to inorganic arsenic may be mediated by these methylated metabolites. If i As methylation is an activation process, then the phenotype for inorganic arsenic methylation may determine risk associated with exposure to this metalloid. We examined inorganic arsenic methylation phenotypes and arsenic (+3 oxidation state) methyltransferase genotypes in four species: three that methylate inorganic arsenic (human (Homo sapiens), rat (Rattus norwegicus), and mouse (Mus musculus)) and one that does not methylate inorganic arsenic (chimpanzee, Pan troglodytes). The predicted protein products from arsenic (+3 oxidation state) methyltransferase are similar in size for rat (369 amino acid residues), mouse (376 residues), and human (375 residues). By comparison, a 275-nucleotide deletion beginning at nucleotide 612 in the chimpanzee gene sequence causes a frameshift that leads to a nonsense mutation for a premature stop codon after amino acid 205. The null phenotype for inorganic arsenic methylation in the chimpanzee is likely due to the deletion in the gene for arsenic (+3 oxidation state) methyltransferase that yields an inactive truncated protein. This lineage-specific loss of function caused by the deletion event must have occurred in the Pan lineage after Homo-Pan divergence about 5 million years ago

  6. On the chemistry of hydrides of N atoms and O$^+$ ions

    CERN Document Server

    Awad, Zainab; Williams, David A

    2016-01-01

    Previous work by various authors has suggested that the detection by Herschel/HIFI of nitrogen hydrides along the low density lines of sight towards G10.6-0.4 (W31C) cannot be accounted for by gas-phase chemical models. In this paper we investigate the role of surface reactions on dust grains in diffuse regions, and we find that formation of the hydrides by surface reactions on dust grains with efficiency comparable to that for H$_2$ formation reconciles models with observations of nitrogen hydrides. However, similar surface reactions do not contribute significantly to the hydrides of O$^+$ ions detected by Herschel/HIFI present along many sight lines in the Galaxy. The O$^+$ hydrides can be accounted for by conventional gas-phase chemistry either in diffuse clouds of very low density with normal cosmic ray fluxes or in somewhat denser diffuse clouds with high cosmic ray fluxes. Hydride chemistry in dense dark clouds appears to be dominated by gas-phase ion-molecule reactions.

  7. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

    2013-09-01

    Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density-functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest-energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.

  8. Investigation of Lithium Metal Hydride Materials for Mitigation of Deep Space Radiation

    Science.gov (United States)

    Rojdev, Kristina; Atwell, William

    2016-01-01

    Radiation exposure to crew, electronics, and non-metallic materials is one of many concerns with long-term, deep space travel. Mitigating this exposure is approached via a multi-faceted methodology focusing on multi-functional materials, vehicle configuration, and operational or mission constraints. In this set of research, we are focusing on new multi-functional materials that may have advantages over traditional shielding materials, such as polyethylene. Metal hydride materials are of particular interest for deep space radiation shielding due to their ability to store hydrogen, a low-Z material known to be an excellent radiation mitigator and a potential fuel source. We have previously investigated 41 different metal hydrides for their radiation mitigation potential. Of these metal hydrides, we found a set of lithium hydrides to be of particular interest due to their excellent shielding of galactic cosmic radiation. Given these results, we will continue our investigation of lithium hydrides by expanding our data set to include dose equivalent and to further understand why these materials outperformed polyethylene in a heavy ion environment. For this study, we used HZETRN 2010, a one-dimensional transport code developed by NASA Langley Research Center, to simulate radiation transport through the lithium hydrides. We focused on the 1977 solar minimum Galactic Cosmic Radiation environment and thicknesses of 1, 5, 10, 20, 30, 50, and 100 g/cm2 to stay consistent with our previous studies. The details of this work and the subsequent results will be discussed in this paper.

  9. Influence of lanthanon hydride catalysts on hydrogen storage properties of sodium alanates

    Institute of Scientific and Technical Information of China (English)

    WU Zhe; CHEN Lixin; XIAO Xuezhang; FAN Xiulin; LI Shouquan; WANG Qidong

    2013-01-01

    NaAlH4 complex hydrides doped with lanthanon hydrides were prepared by hydrogenation of the ball-milled NaH/Al+xmol.% RE-H composites (RE=La,Ce; x=2,4,6) using NaHl and A1 powder as raw materials.The influence of lanthanon hydride catalysts on the hydriding and dehydriding behaviors of the as-synthesized composites were investigated.It was found that the composite doped with 2 mol.% La.H3.01 displayed the highest hydrogen absorption capacity of 4.78 wt.% and desorption capacity of 4.66wt.%,respectively.Moreover,the composite doped with 6 mol% CeH2.51 showed the best hydriding/dehydriding reaction kinetics.The proposed catalytic mechanism for reversible hydrogen storage properties of the composite was attributed to the presence of active LaH3.01 and CeH2.51 particles,which were scattering on the surface of NaH and A1 particles,acting as the catalytic active sites for hydrogen diffusion and playing an important catalytic role in the improved hydriding/dehydriding reaction.

  10. Fracture mechanism of TiAl intermetallics caused by hydride and atomic hydrogen

    Institute of Scientific and Technical Information of China (English)

    高克玮; 王燕斌; 林志; 乔利杰; 褚武扬

    1999-01-01

    Hydrogen embrittlement (HE) of TiAl intermetallics was studied at room temperature. The results showed that there were two forms of HE in TiAl intermetallics, i.e. hydride HE and atomic HE. Most of hydrogen in TiAl intermetallics was transformed into hydrides at room temperature. The hydride exists as (TiAl)Hx for a low hydrogen concentration while it exists in several forms for a higher hydrogen concentration. Stress intensity factor KIC decreased with increase in hydride concentration. KIC decreased further when TiAl intermetallics were charged cathodically with hydrogen in 1 mol/L H2SO4 solution. Stress intensity factor during hydrogen charging KIH was about 50% KIC. 20% of the decrease was caused by hydrides while 30% was caused by atomic hydrogen. Mechanism of HE caused hydrides was the same as any other second phase in nature. Delayed fracture caused by atomic hydrogen resulted from hydrogen induced local plastic deformation.

  11. Interactions between arsenic species and marine algae

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, J.G.

    1978-01-01

    The arsenic concentration and speciation of marine algae varies widely, from 0.4 to 23 ng.mg/sup -1/, with significant differences in both total arsenic content and arsenic speciation occurring between algal classes. The Phaeophyceae contain more arsenic than other algal classes, and a greater proportion of the arsenic is organic. The concentration of inorganic arsenic is fairly constant in macro-algae, and may indicate a maximum level, with the excess being reduced and methylated. Phytoplankton take up As(V) readily, and incorporate a small percentage of it into the cell. The majority of the As(V) is reduced, methylated, and released to the surrounding media. The arsenic speciation in phytoplankton and Valonia also changes when As(V) is added to cultures. Arsenate and phosphate compete for uptake by algal cells. Arsenate inhibits primary production at concentrations as low as 5 ..mu..g.1/sup -1/ when the phosphate concentration is low. The inhibition is competitive. A phosphate enrichment of > 0.3 ..mu..M alleviates this inhibition; however, the As(V) stress causes an increase in the cell's phosphorus requirement. Arsenite is also toxic to phytoplankton at similar concentrations. Methylated arsenic species did not affect cell productivity, even at concentrations of 25 ..mu..g.1/sup -1/. Thus, the methylation of As(V) by the cell produces a stable, non-reactive compound which is nontoxic. The uptake and subsequent reduction and methylation of As(V) is a significant factor in determining the arsenic biogeochemistry of productive systems, and also the effect that the arsenic may have on algal productivity. Therefore, the role of marine algae in determining the arsenic speciation of marine systems cannot be ignored. (ERB)

  12. Arsenic mobilization and immobilization in paddy soils

    Science.gov (United States)

    Kappler, A.; Hohmann, C.; Zhu, Y. G.; Morin, G.

    2010-05-01

    Arsenic is oftentimes of geogenic origin and in many cases bound to iron(III) minerals. Iron(III)-reducing bacteria can harvest energy by coupling the oxidation of organic or inorganic electron donors to the reduction of Fe(III). This process leads either to dissolution of Fe(III)-containing minerals and thus to a release of the arsenic into the environment or to secondary Fe-mineral formation and immobilisation of arsenic. Additionally, aerobic and anaerobic iron(II)-oxidizing bacteria have the potential to co-precipitate or sorb arsenic during iron(II) oxidation at neutral pH that is usually followed by iron(III) mineral precipitation. We are currently investigating arsenic immobilization by Fe(III)-reducing bacteria and arsenic co-precipitation and immobilization by anaerobic iron(II)-oxidizing bacteria in batch, microcosm and rice pot experiments. Co-precipitation batch experiments with pure cultures of nitrate-dependent Fe(II)-oxidizing bacteria are used to quantify the amount of arsenic that can be immobilized during microbial iron mineral precipitation, to identify the minerals formed and to analyze the arsenic binding environment in the precipitates. Microcosm and rice pot experiments are set-up with arsenic-contaminated rice paddy soil. The microorganisms (either the native microbial population or the soil amended with the nitrate-dependent iron(II)-oxidizing Acidovorax sp. strain BoFeN1) are stimulated either with iron(II), nitrate, or oxygen. Dissolved and solid-phase arsenic and iron are quantified. Iron and arsenic speciation and redox state in batch and microcosm experiments are determined by LC-ICP-MS and synchrotron-based methods (EXAFS, XANES).

  13. Arsenic Adsorption Onto Iron Oxides Minerals

    Science.gov (United States)

    Aredes, S.; Klein, B.; Pawlik, M.

    2004-12-01

    The predominant form of arsenic in water is as an inorganic ion. Under different redox conditions arsenic in water is stable in the +5 and +3 oxidation states. Arsenic oxidation state governs its toxicity, chemical form and solubility in natural and disturbed environments. As (III) is found in anoxic environments such as ground water , it is toxic and the common species is the neutral form, H3AsO3. As (V) is found in aerobic conditions such as surface water, it is less toxic and the common species in water are: H2AsO4 - and HAsO4 {- 2}. The water pH determines the predominant arsenate or arsenite species, however, both forms of arsenic can be detected in natural water systems. Iron oxides minerals often form in natural waters and sediments at oxic-anoxic boundaries. Over time they undergo transformation to crystalline forms, such as goethite or hematite. Both As(V) and As(III) sorbs strongly to iron oxides, however the sorption behavior of arsenic is dependent on its oxidation state and the mineralogy of the iron oxides. Competition between arsenic and others ions, such fluoride, sulphate and phosphate also play a role. On the other hand, calcium may increase arsenic adsorption onto iron oxides. Electrokinetic studies and adsorption experiments were carried out in order to determine which conditions favour arsenic adsorption. Hematite, goethite and magnetite as iron based sorbents were used. Test were also conducted with a laterite soil rich in iron minerals. The focus of this study is to evaluate physical and chemical conditions which favour arsenic adsorption onto iron oxides minerals, the results contribute to an understanding of arsenic behaviour in natural and disturbed environments. Furthermore, results could contribute in developing an appropriate remediation technology for arsenic removal in water using iron oxides minerals.

  14. Chromosome analysis of arsenic affected cattle

    Directory of Open Access Journals (Sweden)

    S. Shekhar

    2014-10-01

    Full Text Available Aim: The aim was to study the chromosome analysis of arsenic affected cattle. Materials and Methods: 27 female cattle (21 arsenic affected and 6 normal were selected for cytogenetical study. The blood samples were collected, incubated, and cultured using appropriate media and specific methods. The samples were analyzed for chromosome number and morphology, relative length of the chromosome, arm ratio, and centromere index of X chromosome and chromosomal abnormalities in arsenic affected cattle to that of normal ones. Results: The diploid number of metaphase chromosomes in arsenic affected cattle as well as in normal cattle were all 2n=60, 58 being autosomes and 2 being sex chromosomes. From the centromeric position, karyotyping studies revealed that all the 29 pair of autosomes was found to be acrocentric or telocentric, and the sex chromosomes (XX were submetacentric in both normal and arsenic affected cattle. The relative length of all the autosome pairs and sex chrosomosome pair was found to be higher in normal than that of arsenic affected cattle. The mean arm ratio of X-chromosome was higher in normal than that of arsenic affected cattle, but it is reverse in case of centromere index value of X-chromosome. There was no significant difference of arm ratio and centromere index of X-chromosomes between arsenic affected and normal cattle. No chromosomal abnormalities were found in arsenic affected cattle. Conclusion: The chromosome analysis of arsenic affected cattle in West Bengal reported for the first time in this present study which may serve as a guideline for future studies in other species. These reference values will also help in comparison of cytological studies of arsenic affected cattle to that of various toxicants.

  15. ARSENIC REMOVAL AND ECOLOGICALLY SAFE CONTAINMENT OF ARSENIC-WASTE: A SUSTAINABLE SOLUTION FOR ARSENIC CRISIS IN CAMBODIA

    Science.gov (United States)

    An appalling degree of arsenic contamination in groundwater has affected more than a million people in wide region of Mekong delta flood plain in Cambodia. Arsenic is by far the most toxic species of all naturally occurring groundwater contaminants and disposal of removed arse...

  16. Arsenic Removal by Liquid Membranes

    Directory of Open Access Journals (Sweden)

    Tiziana Marino

    2015-03-01

    Full Text Available Water contamination with harmful arsenic compounds represents one of the most serious calamities of the last two centuries. Natural occurrence of the toxic metal has been revealed recently for 21 countries worldwide; the risk of arsenic intoxication is particularly high in Bangladesh and India but recently also Europe is facing similar problem. Liquid membranes (LMs look like a promising alternative to the existing removal processes, showing numerous advantages in terms of energy consumption, efficiency, selectivity, and operational costs. The development of different LM configurations has been a matter of investigation by several researching groups, especially for the removal of As(III and As(V from aqueous solutions. Most of these LM systems are based on the use of phosphine oxides as carriers, when the metal removal is from sulfuric acid media. Particularly promising for water treatment is the hollow fiber supported liquid membrane (HFSLM configuration, which offers high selectivity, easy transport of the targeted metal ions, large surface area, and non-stop flow process. The choice of organic extractant(s plays an essential role in the efficiency of the arsenic removal. Emulsion liquid membrane (ELM systems have not been extensively investigated so far, although encouraging results have started to appear in the literature. For such LM configuration, the most relevant step toward efficiency is the choice of the surfactant type and its concentration.

  17. Chronic arsenic poisoning from burning high-arsenic-containing coal in Guizhou, China.

    Science.gov (United States)

    Liu, Jie; Zheng, Baoshan; Aposhian, H Vasken; Zhou, Yunshu; Chen, Ming-Liang; Zhang, Aihua; Waalkes, Michael P

    2002-02-01

    Arsenic is an environmental hazard and the reduction of drinking water arsenic levels is under consideration. People are exposed to arsenic not only through drinking water but also through arsenic-contaminated air and food. Here we report the health effects of arsenic exposure from burning high arsenic-containing coal in Guizhou, China. Coal in this region has undergone mineralization and thus produces high concentrations of arsenic. Coal is burned inside the home in open pits for daily cooking and crop drying, producing a high concentration of arsenic in indoor air. Arsenic in the air coats and permeates food being dried producing high concentrations in food; however, arsenic concentrations in the drinking water are in the normal range. The estimated sources of total arsenic exposure in this area are from arsenic-contaminated food (50-80%), air (10-20%), water (1-5%), and direct contact in coal-mining workers (1%). At least 3,000 patients with arsenic poisoning were found in the Southwest Prefecture of Guizhou, and approximately 200,000 people are at risk for such overexposures. Skin lesions are common, including keratosis of the hands and feet, pigmentation on the trunk, skin ulceration, and skin cancers. Toxicities to internal organs, including lung dysfunction, neuropathy, and nephrotoxicity, are clinically evident. The prevalence of hepatomegaly was 20%, and cirrhosis, ascites, and liver cancer are the most serious outcomes of arsenic poisoning. The Chinese government and international organizations are attempting to improve the house conditions and the coal source, and thereby protect human health in this area.

  18. Uptake and Speciation of Inorganic Arsenic with Cellulose Fibre Coated with Yttrium Hydroxide Layer as a Novel Green Sorbent

    Institute of Scientific and Technical Information of China (English)

    安明日; 张晓星; 杨婷; 陈明丽; 王建华

    2012-01-01

    A novel adsorbent was developed by coating yttrium hydroxide precipitate layer on cellulose fibre. This material takes up ca. 98% of 5 μg·L 1 As(Ⅲ) and As(V) at low pH (pH〈7), while a favorable selectivity for As(V) was achieved within pH 11--12. In practice, a mini-column packed with Y(OH)3 precipitate layer coated cellulose fibre particles was incorporated into a sequential injection system for selective uptake of arsenate at pH 11.5. The retained arsenate was afterwards recovered with 50μL of 0.8 mol.L l NaOH solution as eluent, followed by hydride generation in a reaction medium of 2.0 mol·L-1 HCl and 1.0% NaBH4 solution (W/V, in 0.5% NaOH) after pre-reduction of arsenate to arsenite by KI-ascorbic acid (5%, W/V), with detection by atomic fluorescence spec- trometry. Total inorganic arsenic was quantitatively taken up at pH 6.0 by following the same procedure and arsenic speciation was performed by difference. With a sample volume of 1.0 mL, an enrichment factor of 16.4 was derived with a detection limit of 17 ng.L-1 within a linear range of 0.05--2.0μg.L ]. A relative standard deviation (RSD) of 2.6% (0.5 μg·L-1, n= 11) was achieved. The procedure was validated by analyzing arsenic in a certified refer- ence material GBW 09101 (human hair), and speciation process requires no organic solvents, thus Y(OH)3 coated of inorganic arsenic in natural water samples. The entire cellulose fibre provides a green adsorbent.

  19. Complex Hydride Compounds with Enhanced Hydrogen Storage Capacity

    Energy Technology Data Exchange (ETDEWEB)

    Mosher, Daniel A.; Opalka, Susanne M.; Tang, Xia; Laube, Bruce L.; Brown, Ronald J.; Vanderspurt, Thomas H.; Arsenault, Sarah; Wu, Robert; Strickler, Jamie; Anton, Donald L.; Zidan, Ragaiy; Berseth, Polly

    2008-02-18

    The United Technologies Research Center (UTRC), in collaboration with major partners Albemarle Corporation (Albemarle) and the Savannah River National Laboratory (SRNL), conducted research to discover new hydride materials for the storage of hydrogen having on-board reversibility and a target gravimetric capacity of ≥ 7.5 weight percent (wt %). When integrated into a system with a reasonable efficiency of 60% (mass of hydride / total mass), this target material would produce a system gravimetric capacity of ≥ 4.5 wt %, consistent with the DOE 2007 target. The approach established for the project combined first principles modeling (FPM - UTRC) with multiple synthesis methods: Solid State Processing (SSP - UTRC), Solution Based Processing (SBP - Albemarle) and Molten State Processing (MSP - SRNL). In the search for novel compounds, each of these methods has advantages and disadvantages; by combining them, the potential for success was increased. During the project, UTRC refined its FPM framework which includes ground state (0 Kelvin) structural determinations, elevated temperature thermodynamic predictions and thermodynamic / phase diagram calculations. This modeling was used both to precede synthesis in a virtual search for new compounds and after initial synthesis to examine reaction details and options for modifications including co-reactant additions. The SSP synthesis method involved high energy ball milling which was simple, efficient for small batches and has proven effective for other storage material compositions. The SBP method produced very homogeneous chemical reactions, some of which cannot be performed via solid state routes, and would be the preferred approach for large scale production. The MSP technique is similar to the SSP method, but involves higher temperature and hydrogen pressure conditions to achieve greater species mobility. During the initial phases of the project, the focus was on higher order alanate complexes in the phase space

  20. Bioaccumulation of Arsenic by Fungi

    Directory of Open Access Journals (Sweden)

    Ademola O. Adeyemi

    2009-01-01

    Full Text Available Problem statement: Arsenic is a known toxic element and its presence and toxicity in nature is a worldwide environmental problem. The use of microorganisms in bioremediation is a potential method to reduce as concentration in contaminated areas. Approach: In order to explore the possible bioremediation of this element, three filamentous fungi-Aspergillus niger, Serpula himantioides and Trametes versicolor were investigated for their potential abilities to accumulate (and possibly solubilize arsenic from an agar environment consisting of non buffered mineral salts media amended with 0.2, 0.4, 0.6 and 0.8% (w/v arsenopyrite (FeAsS. Growth rates, dry weights, arsenic accumulation and oxalate production by the fungi as well as the pH of the growth media were all assessed during this study. Results: There was no visible solubilization of FeAsS particles underneath any of the growing fungal colonies or elsewhere in the respective agar plates. No specific patterns of growth changes were observed from the growth ratios of the fungi on agar amended with different amounts of FeAsS although growth of all fungi was stimulated by the incorporation of varying amounts of FeAsS into the agar with the exception of A. niger on 0.4% (w/v amended agar and T. versicolor on 0.8% (w/v amended agar. The amounts of dry weights obtained for all three fungi also did not follow any specific patterns with different amounts of FeAsS and the quantities obtained were in the order A. niger > S. himantioides > T. versicolor. All fungi accumulated as in their biomasses with all amounts of FeAsS although to varying levels and T. versicolor was the most effective with all amounts of FeAsS while A. niger was the least effective. Conclusion: The accumulation of arsenic in the biomasses of the test fungi as shown in this study may suggested a role for fungi through their bioaccumulating capabilities as agents in the possible bioremediation of arsenic contaminated environments.

  1. Hijacking membrane transporters for arsenic phytoextraction.

    Science.gov (United States)

    LeBlanc, Melissa S; McKinney, Elizabeth C; Meagher, Richard B; Smith, Aaron P

    2013-01-10

    Arsenic is a toxic metalloid and recognized carcinogen. Arsenate and arsenite are the most common arsenic species available for uptake by plants. As an inorganic phosphate (Pi) analog, arsenate is acquired by plant roots through endogenous Pi transport systems. Inside the cell, arsenate is reduced to the thiol-reactive form arsenite. Glutathione (GSH)-conjugates of arsenite may be extruded from the cell or sequestered in vacuoles by members of the ATP-binding cassette (ABC) family of transporters. In the present study we sought to enhance both plant arsenic uptake through Pi transporter overexpression, and plant arsenic tolerance through ABC transporter overexpression. We demonstrate that Arabidopsis thaliana plants overexpressing the high-affinity Pi transporter family members, AtPht1;1 or AtPht1;7, are hypersensitive to arsenate due to increased arsenate uptake. These plants do not exhibit increased sensitivity to arsenite. Co-overexpression of the yeast ABC transporter YCF1 in combination with AtPht1;1 or AtPht1;7 suppresses the arsenate-sensitive phenotype while further enhancing arsenic uptake. Taken together, our results support an arsenic transport mechanism in which arsenate uptake is increased through Pi transporter overexpression, and arsenic tolerance is enhanced through YCF1-mediated vacuolar sequestration. This work substantiates the viability of coupling enhanced uptake and vacuolar sequestration as a means for developing a prototypical engineered arsenic hyperaccumulator.

  2. 29 CFR 1915.1018 - Inorganic arsenic.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Inorganic arsenic. 1915.1018 Section 1915.1018 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1018 Inorganic arsenic. Note: The requirements applicable to shipyard employment under...

  3. Biotechnology based processes for arsenic removal

    NARCIS (Netherlands)

    Huisman, J.; Olde Weghuis, M.; Gonzalez-Contreras, P.A.

    2011-01-01

    The regulations for arsenic control have become strict. Therefore, better technologies to remove arsenic from bleeds and effluents are desired. In addition, no single solution is suitable for all cases. The properties of the process streams and the storage facilities are major factors determining th

  4. Arsenic and human health effects: A review.

    Science.gov (United States)

    Abdul, Khaja Shameem Mohammed; Jayasinghe, Sudheera Sammanthi; Chandana, Ediriweera P S; Jayasumana, Channa; De Silva, P Mangala C S

    2015-11-01

    Arsenic (As) is ubiquitous in nature and humans being exposed to arsenic via atmospheric air, ground water and food sources are certain. Major sources of arsenic contamination could be either through geological or via anthropogenic activities. In physiological individuals, organ system is described as group of organs that transact collectively and associate with other systems for conventional body functions. Arsenic has been associated with persuading a variety of complications in body organ systems: integumentary, nervous, respiratory, cardiovascular, hematopoietic, immune, endocrine, hepatic, renal, reproductive system and development. In this review, we outline the effects of arsenic on the human body with a main focus on assorted organ systems with respective disease conditions. Additionally, underlying mechanisms of disease development in each organ system due to arsenic have also been explored. Strikingly, arsenic has been able to induce epigenetic changes (in utero) and genetic mutations (a leading cause of cancer) in the body. Occurrence of various arsenic induced health effects involving emerging areas such as epigenetics and cancer along with their respective mechanisms are also briefly discussed.

  5. 29 CFR 1926.1118 - Inorganic arsenic.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Inorganic arsenic. 1926.1118 Section 1926.1118 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Inorganic arsenic. Note: The requirements applicable to construction work under this section are...

  6. Arsenic Consumption in the United States.

    Science.gov (United States)

    Wilson, Denise

    2015-10-01

    Exposure limits for arsenic in drinking water and minimal risk levels (MRLs) for total dietary exposure to arsenic have long been established in the U.S. Multiple studies conducted over the last five years have detected arsenic in foods and beverages including juice, rice, milk, broth (beef and chicken), and others. Understanding whether or not each of these foods or drinks is a concern to certain groups of individuals requires examining which types of and how much arsenic is ingested. In this article, recent studies are reviewed and placed in the context of consumption patterns. When single sources of food or drink are considered in isolation, heavy rice eaters can be exposed to the most arsenic among adults while infants consuming formula containing contaminated organic brown rice syrup are the most exposed group among children. Most food and drink do not contain sufficient arsenic to exceed MRLs. For individuals consuming more than one source of contaminated water or food, however, adverse health effects are more likely. In total, recent studies on arsenic contamination in food and beverages emphasize the need for individual consumers to understand and manage their total dietary exposure to arsenic. PMID:26591332

  7. ARSENIC EFFECTS ON TELOMERE AND TELOMERASE ACTIVITY

    Science.gov (United States)

    Arsenic effects on telomere and telomerase activity. T-C. Zhang, M. T. Schmitt, J. Mo, J. L. Mumford, National Research Council and U.S Environmental Protection Agency, NHEERL, Research Triangle Park, NC 27711Arsenic is a known carcinogen and also an anticancer agent for acut...

  8. Development of delayed hydride cracking resistant-pressure tube

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Suk; Kwon, Sang Chul; Kim, S. S.; Yim, K. S

    2000-10-01

    For the first time, we demonstrate that the pattern of nucleation and growth of a DHC crack is governed by the precipitation of hydrides so that the DHC velocity and K{sub IH} are determined by an angle of the cracking plane and the hydride habit plane 10.7. Since texture controls the distribution of the 10.7 habit plane in Zr-2.5Nb pressure tube, we draw a conclusion that a textural change in Zr-2.5Nb tube from a strong tangential texture to the radial texture shall increase the threshold stress intensity factor, K{sub IH}, and decrease the delayed hydride cracking velocity. This conclusion is also verified by a complimentary experiment showing a linear dependence of DHCV and K{sub IH} with an increase in the basal component in the cracking plane. On the basis of the study on the DHC mechanism and the effect of manufacturing processes on the properties of Zr-2.5Nb tube, we have established a manufacturing procedure to make pressure tubes with improved DHC resistance. The main features of the established manufacturing process consist in the two step-cold pilgering process and the intermediate heat treatment in the {alpha} + {beta} phase for Zr-2.5Nb alloy and in the {alpha} phase for Zr-1Nb-1.2Sn-0.4Fe alloy. The manufacturing of DHC resistant-pressure tubes of Zr-2.5Nb and Zr-1N-1.2Sn-0.4Fe was made in the ChMP zirconium plant in Russia under a joint research with Drs. Nikulina and Markelov in VNIINM (Russia). Zr-2.5Nb pressure tube made with the established manufacturing process has met all the specification requirements put by KAERI. Chracterization tests have been jointly conducted by VNIINM and KAERI. As expected, the Zr-2.5Nb tube made with the established procedure has improved DHC resistance compared to that of CANDU Zr-2.5Nb pressure tube used currently. The measured DHC velocity of the Zr-2.5Nb tube meets the target value (DHCV <5x10{sup -8} m/s) and its other properties also were equivalent to those of the CANDU Zr-2.5Nb tube used currently. The Zr-1Nb-1

  9. Arsenic pesticides and environmental pollution: exposure, poisoning, hazards and recommendations.

    Science.gov (United States)

    El-Bahnasawy, Mamdouh M; Mohammad, Amina El-Hosini; Morsy, Tosson A

    2013-08-01

    Arsenic is a metalloid element. Acute high-dose exposure to arsenic can cause severe systemic toxicity and death. Lower dose chronic arsenic exposure can result in subacute toxicity that can include peripheral sensorimotor neuropathy, skin eruptions, and hepatotoxicity. Long-term effects of arsenic exposure include an in Due to the physiologic effects of the arsenic on all body systems, thus, chronic arsenic-poisoned patient is a major nursing challenge. The critical care nurse provides valuable assessment and interventions that prevent major multisystem complications from arsenic toxicity.

  10. Research plan for arsenic in drinking water

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    The document stresses the implications of recent research findings and emphasizes identification of key strengths and sources of uncertainty and variability in the arsenic risk assessment. This document also explains how information gained through research can: impact the method used in new investigations to assess the risks of arsenic, and support or suggest changes in the assumptiosn and methods used in arsenic risk assessments. This Arsenic Research Plan addresses the protection of human health, especially the research needed to implement the 1996 Safe Drinking Water Act Amendments (SDWAA). It is intended to serve as a blueprint that will be discussed with parties interested in addressing key strengths and uncertainties in the arsenic risk assessment.

  11. Arsenic in Drinking Water—A Global Environmental Problem

    Science.gov (United States)

    Shaofen Wang, Joanna; Wai, Chien M.

    2004-02-01

    Arsenic contamination of groundwater is a global environmental problem affecting a large number of populations, especially in developing countries. The "blackfoot disease"that occurred in Taiwan more than half of a century ago was attributed to drinking arsenic-contaminated water from deep wells containing high concentrations of the trivalent arsenite species. Similar arsenic poisoning cases were reported later in Chinese Inner Mongolia, Bangladesh, and India—all related to drinking groundwater contaminated with arsenic. The maximum contaminant level (MCL) of arsenic in drinking water has been changed recently by the U.S. EPA from 50 ppb to 10 ppb; the compliance date is January 2006. This article summarizes documented global arsenic contamination problems, the regulatory controversy regarding MCL of arsenic in drinking water, and available technologies for removing arsenic from contaminated waters. Methods for analyzing total arsenic and arsenic species in water are also described.

  12. Arsenic Uptake by Muskmelon (Cucumis melo) Plants from Contaminated Water.

    Science.gov (United States)

    Hettick, Bryan E; Cañas-Carrell, Jaclyn E; Martin, Kirt; French, Amanda D; Klein, David M

    2016-09-01

    Arsenic is a carcinogenic element that occurs naturally in the environment. High levels of arsenic are found in water in some parts of the world, including Texas. The aims of this study were to determine the distribution of arsenic in muskmelon (Cucumis melo) plants accumulated from arsenic spiked water and to observe effects on plant biomass. Plants were grown and irrigated using water spiked with variable concentrations of arsenic. Inductively coupled plasma mass spectrometry was used to quantify arsenic in different parts of the plant and fruit. Under all conditions tested in this study, the highest concentrations of arsenic were found in the leaves, soil, and roots. Arsenic in the water had no significant effect on plant biomass. Fruits analyzed in this study had arsenic concentrations of 101 μg/kg or less. Consuming these fruits would result in less arsenic exposure than drinking water at recommended levels. PMID:27460822

  13. Synthesis and properties of arsenic(III)-reactive coumarin-appended benzothiazolines: a new approach for inorganic arsenic detection.

    Science.gov (United States)

    Ezeh, Vivian C; Harrop, Todd C

    2013-03-01

    The EPA has established a maximum contaminant level (MCL) of 10 ppb for arsenic (As) in drinking water requiring sensitive and selective detection methodologies. To tackle this challenge, we have been active in constructing small molecules that react specifically with As(3+) to furnish a new fluorescent species (termed a chemodosimeter). We report in this contribution, the synthesis and spectroscopy of two small-molecule fluorescent probes that we term ArsenoFluors (or AFs) as As-specific chemodosimeters. The AFs (AF1 and AF2) incorporate a coumarin fluorescent reporter coupled with an As-reactive benzothiazoline functional group. AFs react with As(3+) to yield the highly fluorescent coumarin-6 dye (C6) resulting in a 20-25-fold fluorescence enhancement at λem ∼ 500 nm with detection limits of 0.14-0.23 ppb in tetrahydrofuran (THF) at 298 K. The AFs also react with common environmental As(3+) sources such as sodium arsenite in a THF/CHES (N-cyclohexyl-2-aminoethanesulfonic acid) (1:1, pH 9, 298 K) mixture resulting in a modest fluorescence turn-ON (1.5- to 3-fold) due to the quenched nature of coumarin-6 derivatives in high polarity solvents. Bulk analysis of the reaction of the AFs with As(3+) revealed that the C6 derivatives and the Schiff-base disulfide of the AFs (SB1 and SB2) are the ultimate end-products of this chemistry with the formation of C6 being the principle photoproduct responsible for the As(3+)-specific turn-ON. It appears that a likely species that is traversed in the reaction path is an As-hydride-ligand complex that is a putative intermediate in the proposed reaction path. PMID:23421428

  14. Speciation of Arsenic in Exfoliated Urinary Bladder Epithelial Cells from Individuals Exposed to Arsenic in Drinking Water

    Science.gov (United States)

    Hernández-Zavala, Araceli; Valenzuela, Olga L.; Matous̆ek, Tomás̆; Drobná, Zuzana; Dĕdina, Jir̆í; García-Vargas, Gonzalo G.; Thomas, David J.; Del Razo, Luz M.; Stýblo, Miroslav

    2008-01-01

    Background The concentration of arsenic in urine has been used as a marker of exposure to inorganic As (iAs). Relative proportions of urinary metabolites of iAs have been identified as potential biomarkers of susceptibility to iAs toxicity. However, the adverse effects of iAs exposure are ultimately determined by the concentrations of iAs metabolites in target tissues. Objective In this study we examined the feasibility of analyzing As species in cells that originate in the urinary bladder, a target organ for As-induced cancer in humans. Methods Exfoliated bladder epithelial cells (BECs) were collected from urine of 21 residents of Zimapan, Mexico, who were exposed to iAs in drinking water. We determined concentrations of iAs, methyl-As (MAs), and dimethyl-As (DMAs) in urine using conventional hydride generation-cryotrapping-atomic absorption spectrometry (HG-CT-AAS). We used an optimized HG-CT-AAS technique with detection limits of 12–17 pg As for analysis of As species in BECs. Results All urine samples and 20 of 21 BEC samples contained detectable concentrations of iAs, MAs, and DMAs. Sums of concentrations of these As species in BECs ranged from 0.18 to 11.4 ng As/mg protein and in urine from 4.8 to 1,947 ng As/mL. We found no correlations between the concentrations or ratios of As species in BECs and in urine. Conclusion These results suggest that urinary levels of iAs metabolites do not necessarily reflect levels of these metabolites in the bladder epithelium. Thus, analysis of As species in BECs may provide a more effective tool for risk assessment of bladder cancer and other urothelial diseases associated with exposures to iAs. PMID:19079716

  15. Arsenic burden survey among refuse incinerator workers

    Directory of Open Access Journals (Sweden)

    Chao Chung-Liang

    2005-01-01

    Full Text Available Background: Incinerator workers are not considered to have arsenic overexposure although they have the risk of overexposure to other heavy metals. Aim: To examine the relationship between arsenic burden and risk of occupational exposure in employees working at a municipal refuse incinerator by determining the concentrations of arsenic in the blood and urine. Settings and Design: The workers were divided into three groups based on their probability of contact with combustion-generated residues, namely Group 1: indirect contact, Group 2: direct contact and Group 3: no contact. Healthy age- and sex-matched residents living in the vicinity were enrolled as the control group. Materials and Methods: Heavy metal concentrations were measured by atomic absorption spectrophotometer. Downstream rivers and drinking water of the residents were examined for environmental arsenic pollution. A questionnaire survey concerning the contact history of arsenic was simultaneously conducted. Statistical analysis: Non-parametric tests, cross-tabulation and multinomial logistic regression. Results: This study recruited 122 incinerator workers. The urine and blood arsenic concentrations as well as incidences of overexposure were significantly higher in the workers than in control subjects. The workers who had indirect or no contact with combustion-generated residues had significantly higher blood arsenic level. Arsenic contact history could not explain the difference. Airborne and waterborne arsenic pollution were not detected. Conclusion: Incinerator workers run the risk of being exposed to arsenic pollution, especially those who have incomplete protection in the workplace even though they only have indirect or no contact with combustion-generated pollutants.

  16. Factors Affecting Arsenic Methylation in Arsenic-Exposed Humans: A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Hui Shen

    2016-02-01

    Full Text Available Chronic arsenic exposure is a critical public health issue in many countries. The metabolism of arsenic in vivo is complicated because it can be influenced by many factors. In the present meta-analysis, two researchers independently searched electronic databases, including the Cochrane Library, PubMed, Springer, Embase, and China National Knowledge Infrastructure, to analyze factors influencing arsenic methylation. The concentrations of the following arsenic metabolites increase (p< 0.000001 following arsenic exposure: inorganic arsenic (iAs, monomethyl arsenic (MMA, dimethyl arsenic (DMA, and total arsenic. Additionally, the percentages of iAs (standard mean difference (SMD: 1.00; 95% confidence interval (CI: 0.60–1.40; p< 0.00001 and MMA (SMD: 0.49; 95% CI: 0.21–0.77; p = 0.0006 also increase, while the percentage of DMA (SMD: −0.57; 95% CI: −0.80–−0.31; p< 0.0001, primary methylation index (SMD: −0.57; 95% CI: −0.94–−0.20; p = 0.002, and secondary methylation index (SMD: −0.27; 95% CI: −0.46–−0.90; p = 0.004 decrease. Smoking, drinking, and older age can reduce arsenic methylation, and arsenic methylation is more efficient in women than in men. The results of this analysis may provide information regarding the role of arsenic oxidative methylation in the arsenic poisoning process.

  17. Both Phosphorus Fertilizers and Indigenous Bacteria Enhance Arsenic Release into Groundwater in Arsenic-Contaminated Aquifers.

    Science.gov (United States)

    Lin, Tzu-Yu; Wei, Chia-Cheng; Huang, Chi-Wei; Chang, Chun-Han; Hsu, Fu-Lan; Liao, Vivian Hsiu-Chuan

    2016-03-23

    Arsenic (As) is a human carcinogen, and arsenic contamination in groundwater is a worldwide public health concern. Arsenic-affected areas are found in many places but are reported mostly in agricultural farmlands, yet the interaction of fertilizers, microorganisms, and arsenic mobilization in arsenic-contaminated aquifers remains uncharacterized. This study investigates the effects of fertilizers and bacteria on the mobilization of arsenic in two arsenic-contaminated aquifers. We performed microcosm experiments using arsenic-contaminated sediments and amended with inorganic nitrogenous or phosphorus fertilizers for 1 and 4 months under aerobic and anaerobic conditions. The results show that microcosms amended with 100 mg/L phosphorus fertilizers (dipotassium phosphate), but not nitrogenous fertilizers (ammonium sulfate), significantly increase aqueous As(III) release in arsenic-contaminated sediments under anaerobic condition. We also show that concentrations of iron, manganese, potassium, sodium, calcium, and magnesium are increased in the aqueous phase and that the addition of dipotassium phosphate causes a further increase in aqueous iron, potassium, and sodium, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicates that the dominant microbial phylum is shifted from α-proteobacteria to β- and γ-proteobacteria when the As(III) is increased and phosphate is added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of arsenic to groundwater in arsenic-contaminated sediments under anaerobic condition. Our study suggests that agricultural activity such as the use of fertilizers and monitoring phosphate concentration in groundwater should be taken into consideration for the management of arsenic in groundwater.

  18. Cellular distribution of arsenic and other elements in hyperaccumulator Pteris nervosa and their relations to arsenic accumulation

    Institute of Scientific and Technical Information of China (English)

    CHEN Tongbin; HUANG Zechun; HUANG Yuying; XIE Hua; LIAO Xiaoyong

    2003-01-01

    Synchrotron radiation X-ray fluorescencespectroscopy (SRXRF) was used to study the cellular distri-butions of arsenic and other elements in root, petiole, pinna of a newly discovered arsenic hyperaccumulator, Pteris nervosa. It was shown that there was a trend in P. nervosa totransport arsenic from cortex tissue to vascular tissue in root, and keep arsenic in vascular during transportation in petiole, and transport arsenic from vascular tissue to adaxial cortex tissues in midrib of pinnae. More arsenic was accumulated in mesophyll than in epidermis in pinnae. The distributions of some elements, such as K, Ca, Mn, Fe, Cu, Zn, in petiole, midrib and pinna were similar to that of arsenic, indicating that those cations might cooperate with arsenic in those transportation processes; whereas the distributions of Cl and Br in pinna were the reverse of that of arsenic, indicating that those anions might compete with arsenic in pinna of P. nervosa.

  19. Renin–angiotensin–aldosterone system related gene polymorphisms and urinary total arsenic is related to chronic kidney disease

    International Nuclear Information System (INIS)

    A recent study demonstrated that an increased risk of chronic kidney disease (CKD) was associated with high urinary total arsenic levels. However, whether genomic instability is related to CKD remains unclear. An association between CKD and genetic polymorphisms of regulation enzymes of the renin–angiotensin–aldosterone system (RAAS), such as angiotensin-converting enzyme (ACE), angiotensinogen (AGT), angiotensin II type I receptor (AT1R), and aldosterone synthase (CYP11B2) has not been shown. The aim of the present study was to investigate the relationship between arsenic, genetic polymorphisms of RAAS enzymes and CKD. A total of 233 patients and 449 age- and gender-matched controls were recruited from the Taipei Medical University Hospital, Taipei Municipal Wan Fang Hospital and the Shin Kong Wu Ho-Su Memorial Hospital. Concentrations of urinary arsenic were determined by a high-performance liquid chromatography-linked hydride generator, and atomic absorption spectrometry. Polymorphisms of ACE(I/D), AGT(A[− 20]C), (T174M), (M235T), AT1R(A1166C) and CYP11B2(C[− 344]T) were examined by polymerase chain reaction and restriction fragment length polymorphism. Subjects carrying the CYP11B2 TT genotype had a higher odds ratio (OR), 1.39 (0.96–2.01), of CKD; while those with the AGT(A[− 20]C) CC genotype had an inverse OR of CKD (0.20 (0.05–0.81)), and a high-risk genotype was defined as A/A + A/C for AGT(A[− 20C]) and T/T for CYP11B2(C[− 344]T). The trend test showed a higher OR for CKD in patients who had either high urinary total arsenic levels or carried the high-risk genotype, or both, compared to patients with low urinary total arsenic levels, who carried the low-risk genotype, and could also be affected by the hypertension or diabetes status. - Highlights: • AGT(− 20 C) and CYP11B2(− 344 T) genotypes were significantly associated with CKD. • Combined effect of high-risk genotypes and high urinary total arsenic on OR of CKD. • Combined

  20. Renin–angiotensin–aldosterone system related gene polymorphisms and urinary total arsenic is related to chronic kidney disease

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Jen [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Huang, Ya-Li [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan (China); Chen, Tzen-Wen [Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Lin, Yuh-Feng [Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, New Taipei, Taiwan (China); Huang, Chao-Yuan [Department of Urology, National Taiwan University Hospital, College of Medicine National Taiwan University, Taipei, Taiwan (China); Lin, Ying-Chin [Department of Family Medicine, Shung Ho Hospital, Taipei Medical University, New Taipei, Taiwan (China); Department of Health Examination, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan (China); Division of Family Medicine, School of Medicine, Taipei Medical University, Taipei, Taiwan (China); Han, Bor-Cheng [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2014-09-01

    A recent study demonstrated that an increased risk of chronic kidney disease (CKD) was associated with high urinary total arsenic levels. However, whether genomic instability is related to CKD remains unclear. An association between CKD and genetic polymorphisms of regulation enzymes of the renin–angiotensin–aldosterone system (RAAS), such as angiotensin-converting enzyme (ACE), angiotensinogen (AGT), angiotensin II type I receptor (AT1R), and aldosterone synthase (CYP11B2) has not been shown. The aim of the present study was to investigate the relationship between arsenic, genetic polymorphisms of RAAS enzymes and CKD. A total of 233 patients and 449 age- and gender-matched controls were recruited from the Taipei Medical University Hospital, Taipei Municipal Wan Fang Hospital and the Shin Kong Wu Ho-Su Memorial Hospital. Concentrations of urinary arsenic were determined by a high-performance liquid chromatography-linked hydride generator, and atomic absorption spectrometry. Polymorphisms of ACE(I/D), AGT(A[− 20]C), (T174M), (M235T), AT1R(A1166C) and CYP11B2(C[− 344]T) were examined by polymerase chain reaction and restriction fragment length polymorphism. Subjects carrying the CYP11B2 TT genotype had a higher odds ratio (OR), 1.39 (0.96–2.01), of CKD; while those with the AGT(A[− 20]C) CC genotype had an inverse OR of CKD (0.20 (0.05–0.81)), and a high-risk genotype was defined as A/A + A/C for AGT(A[− 20C]) and T/T for CYP11B2(C[− 344]T). The trend test showed a higher OR for CKD in patients who had either high urinary total arsenic levels or carried the high-risk genotype, or both, compared to patients with low urinary total arsenic levels, who carried the low-risk genotype, and could also be affected by the hypertension or diabetes status. - Highlights: • AGT(− 20 C) and CYP11B2(− 344 T) genotypes were significantly associated with CKD. • Combined effect of high-risk genotypes and high urinary total arsenic on OR of CKD. • Combined

  1. Influence of hydrides orientation on strain, damage and failure of hydrided zircaloy-4; Influence de l'orientation des hydrures sur les modes de deformation, d'endommagement et de rupture du zircaloy-4 hydrure

    Energy Technology Data Exchange (ETDEWEB)

    Racine, A

    2005-09-15

    In pressurized water reactors of nuclear power plants, fuel pellets are contained in cladding tubes, made of Zirconium alloy, for instance Zircaloy-4. During their life in the primary water of the reactor (155 bars, 300 C), cladding tubes are oxidized and consequently hydrided. A part of the hydrogen given off precipitates as Zirconium hydrides in the bulk material and embrittles the material. This embrittlement depends on many parameters, among which hydrogen content and orientation of hydrides with respect to the applied stress. This investigation is devoted to the influence of the orientation of hydrides with respect to the applied stress on strain, damage and failure mechanisms. Macroscopic and SEM in-situ ring tensile tests are performed on cladding tube material (unirradiated cold worked stress-relieved Zircaloy-4) hydrided with about 200 and 500 wppm hydrogen, and with different main hydrides orientation: either parallel or perpendicular to the circumferential tensile direction. We get the mechanical response of the material as a function of hydride orientation and hydrogen content and we investigate the deformation, damage and failure mechanisms. In both cases, digital image correlation techniques are used to estimate local and global strain distributions. Neither the tensile stress-strain response nor the global and local strain modes are significantly affected by hydrogen content or hydride orientation, but the failure modes are strongly modified. Indeed, only 200 wppm radial hydrides embrittle Zy-4: sample fail in the elastic domain at about 350 MPa before strain bands could develop; whereas in other cases sample reach at least 750 MPa before necking and final failure, in ductile or brittle mode. To model this particular heterogeneous material behavior, a non-coupled damage approach which takes into account the anisotropic distribution of the hydrides is proposed. Its parameters are identified from the macroscopic strain field measurements and a

  2. Improved Electrochemical Performance of Surface-Modified Metal Hydride Electrodes

    Institute of Scientific and Technical Information of China (English)

    YANG Kai; WU Feng; CHEN Shi; ZHANG Cun-zhong

    2005-01-01

    A novel plating process was applied to the surface modification of the metal hydride (MH) electrode of the MH/Ni batteries. The electrode was plated with a thin nickel film about 0.1 μm thick by using multi-arc ion plating technique. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to analyze the electrodes. Influence of the surface modification on the performance of the MH/Ni batteries was studied. It is shown that the surface modification could enhance the electrode conductivity and decrease the batteries ohimic resistance by 28.2 %. After surface modification, the discharge capacity of modification also improves the cyclic durability of the batteries. The inner pressure of the batteries with modified electrode during overcharging is much lower than that with unmodified electrode. The experimental results demonstrate that this process is an effective way for the surface modification of the electrode of MH/Ni batteries.

  3. Superhalogens as Building Blocks of Complex Hydrides for Hydrogen Storage

    CERN Document Server

    Srivastava, Ambrish Kumar

    2016-01-01

    Superhalogens are species whose electron affinity (EA) or vertical detachment energy (VDE) exceed to those of halogen. These species typically consist of a central electropositive atom with electronegative ligands. The EA or VDE of species can be further increased by using superhalogen as ligands, which are termed as hyperhalogen. Having established BH4- as a superhalogen, we have studied BH4-x(BH4)x- (x = 1 to 4) hyperhalogen anions and their Li-complexes, LiBH4-x(BH4)x using density functional theory. The VDE of these anions is larger than that of BH4-, which increases with the increase in the number of peripheral BH4 moieties (x). The hydrogen storage capacity of LiBH4-x(BH4)x complexes is higher but binding energy is smaller than that of LiBH4, a typical complex hydride. The linear correlation between dehydrogenation energy of LiBH4-x(BH4)x complexes and VDE of BH4-x(BH4)x- anions is established. These complexes are found to be thermodynamically stable against dissociation into LiBH4 and borane. This stud...

  4. Unloading Effect on Delayed Hydride Cracking in Zirconium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Suk; Kim, Sung Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-05-15

    It is well-known that a tensile overload retards not only the crack growth rate (CGR) in zirconium alloys during the delayed hydride cracking (DHC) tests but also the fatigue crack growth rate in metals, the cause of which is unclear to date. A considerable decrease in the fatigue crack growth rate due to overload is suggested to occur due either to the crack closure or to compressive stresses or strains arising from unloading of the overload. However, the role of the crack closure or the compressive stress in the crack growth rate remains yet to be understood because of incomplete understanding of crack growth kinetics. The aim of this study is to resolve the effect of unloading on the CGR of zirconium alloys, which comes in last among the unresolved issues as listed above. To this end, the CGRs of the Zr-2.5Nb tubes were determined at a constant temperature under the cyclic load with the load ratio, R changing from 0.13 to 0.66 where the extent of unloading became higher at the lower R. More direct evidence for the effect of unloading after an overload is provided using Simpson's experiment investigating the effect on the CGR of a Zr-2.5Nb tube of the stress states of the prefatigue crack tip by unloading or annealing after the formation of a pre-fatigue crack

  5. Synthesis and Hydrogen Desorption Properties of Aluminum Hydrides.

    Science.gov (United States)

    Jeong, Wanseop; Lee, Sang-Hwa; Kim, Jaeyong

    2016-03-01

    Aluminum hydride (AlH3 or alane) is known to store maximum 10.1 wt.% of hydrogen at relatively low temperature (hydrogen desorption are still not clear. To understand the desorption properties of hydrogen in alane, thermodynamically stable α-AlH3 was synthesized by employing an ethereal reaction method. The dependence of pathways on phase formation and the properties of hydrogen evolution were investigated, and the results were compared with the ones for γ-AlH3. It was found that γ-AlH3 requires 10 degrees C higher than that of γ-AlH3 to form, and its decomposition rate demonstrated enhanced endothermic stabilities. For desorption, all hydrogen atoms of alane evolved under an isothermal condition at 138 degrees C in less than 1 hour, and the sample completely transformed to pure aluminum. Our results show that the total amount of desorbed hydrogen from α-AlH3 exceeded 9.05 wt.%, with a possibility of further increase. Easy synthesis, thermal stability, and a large amount of hydrogen desorption of alane fulfill the requirements for light-weight hydrogen storage materials once the pathway of hydrogen cycling is provided.

  6. The joint effects of arsenic and risk diplotypes of insulin-like growth factor binding protein-3 in renal cell carcinoma.

    Science.gov (United States)

    Huang, Chao-Yuan; Huang, Ya-Li; Pu, Yeong-Shiau; Shiue, Horng-Sheng; Chen, Wei-Jen; Chen, Shih-Shan; Lin, Ying-Chin; Su, Chien-Tien; Hsueh, Yu-Mei

    2016-07-01

    The association between renal cell carcinoma (RCC) and diabetes mellitus (DM), alcohol consumption, insulin-like growth factor binding protein-3 (IGFBP-3) gene, and arsenic exposure, has been the subject of independent studies. However, few studies have examined the combined effect of these factors on RCC risk. The aim of this study was to examine the association between these risk factors and the odds ratio (OR) of RCC. A hospital-based case-control study was conducted in 398 RCC patients and 756 age- and gender-matched non-cancer controls. Genomic DNA was used to examine the genotype of IRS-1 (Gly972Arg), PI3-K (Met362Ile), IGFBP-3 (A[-202]C), and IGFBP-3 (C[-1590]A) by PCR-RFLP. Profiles of urinary arsenic were measured by high performance liquid chromatography linked with hydride generator and atomic absorption spectrometry. Participants who had never consumed alcohol and who had high total levels of urinary arsenic and DM had a high OR of RCC. IGFBP-3 (A[-202]C) and IGFBP-3 (C[-1590]A) were in linkage disequilibrium. Participants carrying high-risk IGFBP-3 diplotypes A-C/C-C, A-A/A-C, and C-A/C-A had a significantly higher odds ratio (OR) and 95% confidence interval (2.80, 1.91-4.12) of RCC compared to those carrying other IGFBP-3 diplotypes. This is the first study to show that borderline significant interaction of high total levels of urinary arsenic and IGFBP-3 high-risk diplotypes significantly enhanced the OR of RCC. Our data also provide evidence that subjects with more risk factors (e.g., high total levels of urinary arsenic, never consumed alcohol, IGFBP-3 high-risk diplotypes) may experience a higher OR of RCC. PMID:27038904

  7. Airborne arsenic and urinary excretion of arsenic metabolites during boiler cleaning operations in a Slovak coal-fired power plant.

    OpenAIRE

    Yager, J W; Hicks, J B; FABIANOVA, E

    1997-01-01

    Little information is available on the relationship between occupational exposure to inorganic arsenic in coal fly ash and urinary excretion of arsenic metabolites. This study ws undertaken in a coal-fired power plant in Slovakia during a routine maintenance outage. Arsenic was measured in the breathing zone of workers during 5 consecutive workdays, and urine samples were obtained for analysis of arsenic metabolites--inorganic arsenic (Asi), monomethylarsonic acid (MMA), and dimethylarsinic a...

  8. ARSENIC SPECIATION IN CARROT EXTRACTS WITH AN EMPHASIS ON THE DETECTION OF MMA(III) AND MMTA

    Science.gov (United States)

    The two predominant routes of arsenic exposure are dietary ingestion and drinking water consumption. Dietary arsenic, unlike drinking water arsenic, contains a variety of arsenicals with dramatically different toxicities. The list of arsenicals detected in dietary samples conti...

  9. Systematic identification of arsenic-binding proteins reveals that hexokinase-2 is inhibited by arsenic.

    Science.gov (United States)

    Zhang, Hai-Nan; Yang, Lina; Ling, Jian-Ya; Czajkowsky, Daniel M; Wang, Jing-Fang; Zhang, Xiao-Wei; Zhou, Yi-Ming; Ge, Feng; Yang, Ming-Kun; Xiong, Qian; Guo, Shu-Juan; Le, Huang-Ying; Wu, Song-Fang; Yan, Wei; Liu, Bingya; Zhu, Heng; Chen, Zhu; Tao, Sheng-Ce

    2015-12-01

    Arsenic is highly effective for treating acute promyelocytic leukemia (APL) and has shown significant promise against many other tumors. However, although its mechanistic effects in APL are established, its broader anticancer mode of action is not understood. In this study, using a human proteome microarray, we identified 360 proteins that specifically bind arsenic. Among the most highly enriched proteins in this set are those in the glycolysis pathway, including the rate-limiting enzyme in glycolysis, hexokinase-1. Detailed biochemical and metabolomics analyses of the highly homologous hexokinase-2 (HK2), which is overexpressed in many cancers, revealed significant inhibition by arsenic. Furthermore, overexpression of HK2 rescued cells from arsenic-induced apoptosis. Our results thus strongly implicate glycolysis, and HK2 in particular, as a key target of arsenic. Moreover, the arsenic-binding proteins identified in this work are expected to serve as a valuable resource for the development of synergistic antitumor therapeutic strategies.

  10. A broad view of arsenic.

    Science.gov (United States)

    Jones, F T

    2007-01-01

    In the mind of the general public, the words "arsenic" and "poison" have become almost synonymous. Yet, As is a natural metallic element found in low concentrations in virtually every part of the environment, including foods. Mining and smelting activities are closely associated with As, and the largest occurrence of As contamination in the United States is near the gold mines of northern Nevada. Inhabitants of Bangladesh and surrounding areas have been exposed to water that is naturally and heavily contaminated with As, causing what the World Health Organization has described as the worst mass poisoning in history. Although readily absorbed by humans, most inorganic As (>90%) is rapidly cleared from the blood with a half-life of 1 to 2 h, and 40 to 70% of the As intake is absorbed, metabolized, and excreted within 48 h. Arsenic does not appreciably bioaccumulate, nor does it biomagnify in the food chain. The United States has for some time purchased more As than any other country in the world, but As usage is waning, and further reductions appear likely. Arsenic is used in a wide variety of industrial applications, from computers to fireworks. All feed additives used in US poultry feeds must meet the strict requirements of the US Food and Drug Administration Center for Veterinary Medicine (Rockville, MD) before use. Although some public health investigators have identified poultry products as a potentially significant source of total As exposure for Americans, studies consistently demonstrate that <1% of samples tested are above the 0.5 ppm limit established by the US Food and Drug Administration Center for Veterinary Medicine. Although laboratory studies have demonstrated the possibility that As in poultry litter could pollute ground waters, million of tons of litter have been applied to the land, and no link has been established between litter application and As contamination of ground water. Yet, the fact that <2% of the United States population is involved in

  11. Determination of As(III) and As(V) in soils using sequential extraction combined with flow injection hydride generation atomic fluorescence detection

    International Nuclear Information System (INIS)

    An analytical procedure for determination of As(III) and As(V) in soils using sequential extraction combined with flow injection (FI) hydride generation atomic fluorescence spectrometry (HG-AFS) was presented. The soils were sequentially extracted by water, 0.6 mol l-1 KH2PO4 solution, 1% (v/v) HCl solution and 1% (w/v) NaOH solution. The arsenite (As(III)) in extract was analyzed by HG-AFS in the medium of 0.1 mol l-1 citric acid solution, then the total arsenic in extract was determined by HG-AFS using on-line reduction of arsenate with L-cysteine. The concentration of arsenate (As(V)) was calculated by the difference. The optimum conditions of extraction and determination were studied in detail. The detection limit (3σ) for As(III) and As(V) were 0.11 and 0.07 μg l-1, respectively. The relative standard deviation (R.S.D.) was 1.43% (n=11) at the 10 μg l-1 As level. The method was applied in the determination of As(III) and As(V) of real soils and the recoveries of As(III) and As(V) were in the range of 89.3-118 and 80.4-111%, respectively

  12. Social implications of arsenic poisoning in Bangladesh.

    Science.gov (United States)

    Hassan, M Manzurul; Atkins, Peter J; Dunn, Christine E

    2005-11-01

    Besides its toxicity, groundwater arsenic contamination creates widespread social problems for its victims and their families in Bangladesh. There is, for instance, a tendency to ostracise arsenic-affected people, arsenicosis being thought of as a contagious disease. Within the community, arsenic-affected people are barred from social activities and often face rejection, even by their immediate family members. Women with visible arsenicosis symptoms are unable to get married and some affected housewives are divorced by their husbands. Children with symptoms are not sent to school in an effort to hide the problem. This paper employs mainly qualitative methods to interpret people's understandings about the toxic impact of groundwater arsenic poisoning on their social lives. Arsenic-affected patients in southwest Bangladesh were asked to determine their 'own priorities' in measuring arsenic toxicity on their social activities and to explore their perceptions about their own survival strategies. We found that patients' experiences reveal severe negative social impacts, and a sharp difference of perceptions about arsenic and social issues between arsenicosis patients and unaffected people.

  13. Arsenic contamination and arsenicosis in China

    International Nuclear Information System (INIS)

    Arsenicosis is a serious environmental chemical disease in China mainly caused by drinking water from pump wells contaminated by high levels of arsenic. Chronic exposure of humans to high concentrations of arsenic in drinking water is associated with skin lesions, peripheral vascular disease, hypertension, blackfoot disease, and high risk of cancers. Lead by the Ministry of Health of China, we carried out a research about arsenicosis in China recently. Areas contaminated with arsenic from drinking water are determined by 10% pump well water sample method while areas from burning coal are determined by existing data. Two epidemic areas of Shanxi Province and Inner Mongolia are investigated for the distribution of pump wells containing high arsenic. Well water in all the investigated villages of Shanxi Province showed polluted by high arsenic, and the average rate of unsafe pump well water is 52%. In Inner Mongolia, the high percentage of pump wells containing elevated arsenic is found only in a few villages. The average rate of unsafe pump well water is 11%. From our research, we find that new endemic areas are continuously emerging in China. Up to now, epidemic areas of arsenicosis mainly involve eight provinces and 37 counties in China. In the affected areas, the discovery of wells and coal with high levels of arsenic is continuing sporadically, and a similar scattered distribution pattern of patients is also being observed

  14. [Competitive Microbial Oxidation and Reduction of Arsenic].

    Science.gov (United States)

    Yang, Ting-ting; Bai, Yao-hui; Liang, Jin-song; Huo, Yang; Wang, Ming-xing; Yuan, Lin-ijang

    2016-02-15

    Filters are widely applied in drinking water treatment plants. Our previous study, which explored the asenic redox in a filter of drinking water plant treating underground water, found that As3+ could be oxidized to As5+ by biogenic manganese oxides, while As5+ could be reduced to As3+ by some microbial arsenic reductases in the biofilter system. This microbial competition could influence the system stability and treatment efficiency. To explore its mechanism, this study selected a manganese-oxidizing bacterial strain (Pseudomonas sp. QJX-1) and a arsenic-reducing strain (Brevibacterium sp. LSJ-9) to investigate their competitive relationship in nutrient acquisition and arsenic redox in the presence of Mn2+, As3+ or As5+ The results revealed that the concentration and valence of Mn and As varied with different reaction time; biological manganese oxides dominated the arsenic redox by rapidly oxidizing the As3+ in the existing system and the As3+ generated by arsenic reductase into As. PCR and RT-PCR results indicated that the arsenic reductase (arsC) was inhibited by the manganese oxidase (cumA). The expression of 16S rRNA in QJX-1 was two orders of magnitude higher than that in LSJ-9, which implied QJX-1 was dominant in the bacterial growth. Our data revealed that hydraulic retention time was critical to the valence of arsenic in the effluent of filter in drinking water treatment plant.

  15. [Competitive Microbial Oxidation and Reduction of Arsenic].

    Science.gov (United States)

    Yang, Ting-ting; Bai, Yao-hui; Liang, Jin-song; Huo, Yang; Wang, Ming-xing; Yuan, Lin-ijang

    2016-02-15

    Filters are widely applied in drinking water treatment plants. Our previous study, which explored the asenic redox in a filter of drinking water plant treating underground water, found that As3+ could be oxidized to As5+ by biogenic manganese oxides, while As5+ could be reduced to As3+ by some microbial arsenic reductases in the biofilter system. This microbial competition could influence the system stability and treatment efficiency. To explore its mechanism, this study selected a manganese-oxidizing bacterial strain (Pseudomonas sp. QJX-1) and a arsenic-reducing strain (Brevibacterium sp. LSJ-9) to investigate their competitive relationship in nutrient acquisition and arsenic redox in the presence of Mn2+, As3+ or As5+ The results revealed that the concentration and valence of Mn and As varied with different reaction time; biological manganese oxides dominated the arsenic redox by rapidly oxidizing the As3+ in the existing system and the As3+ generated by arsenic reductase into As. PCR and RT-PCR results indicated that the arsenic reductase (arsC) was inhibited by the manganese oxidase (cumA). The expression of 16S rRNA in QJX-1 was two orders of magnitude higher than that in LSJ-9, which implied QJX-1 was dominant in the bacterial growth. Our data revealed that hydraulic retention time was critical to the valence of arsenic in the effluent of filter in drinking water treatment plant. PMID:27363151

  16. Determination of As(III) and As(V) by Flow Injection-Hydride Generation-Atomic Absorption Spectrometry via On-line Reduction of As(V) by KI

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Hansen, Elo Harald

    1997-01-01

    interferents. Thus, without impairing the assay, interferents such as Cu, Co, Ni and Se could, at a As(V) level of 5 mu g l(-1), be tolerated at a weight excess of 2000, 30000, 200 and 200 times, respectively. The assay of a certified drinking water sample by means of multiple standard addition (five levels......A volume-based flow injection (FI) procedure is described for the determination and speciation of trace inorganic arsenic, As(III) and As(V), via hydride generation-atomic absorption spectrometry (HG-AAS) of As(III). The determination of total arsenic is obtained by on-line reduction of As(V) to As...... reactor immersed in a water bath at 10 degrees C. By using the very same volume-based FI-HG-AAS system without the heating and cooling reactors, and employing mild hydrochloric acid conditions, As(V) is not converted to arsine, thereby allowing the selective determination of As(III). The injected sample...

  17. Arsenic adsorption of lateritic soil, limestone powder, lime and fly ash on arsenic-contaminated soil

    Directory of Open Access Journals (Sweden)

    Wuthiphun, L.

    2007-05-01

    Full Text Available Arsenic adsorption efficiency of soil covering materials (lateritic soil, limestone powder, lime and fly ash on arsenic-contaminated soil obtained from Ronpiboon District, Nakhon Sri Thammarat Province tosolve arsenic air pollution problem was investigated using batch experiments. The four types of the aforementioned soil covering materials were examined to determine their arsenic adsorption efficiency, equilibriumtime as well as adsorption isotherms.The results revealed that among soil covering materials mixed with arsenic-contaminated soil at 10% w/w, the efficiency of arsenic adsorption of fly ash, lateritic soil, lime and limestone powder were 84, 60,38 and 1% respectively. The equilibrium time for lateritic soil at pH 4 was achieved within 4 hrs, whereas pH 7 and 12, the equilibrium time was 6 hrs. For fly ash, 2 hrs were required to reach the equilibrium at pH 12, while the equilibrium time was attained within 6 hrs at pH 4 and 7. Furthermore, lateritic soil possessedhigh arsenic adsorption efficiency at pH 7 and 4 and best fit with the Langmuir isotherm. The fly ash showing high arsenic adsorption efficiency at pH 12 and 7 fit the Freundlich isotherm at pH 12 and Langmuirisotherm at pH 7.This indicated that lateritic soil was suitable for arsenic adsorption at low pH, whilst at high pH,arsenic was well adsorbed by fly ash. The Freundlich and Langmuir isotherm could be used to determine quantities of soil covering materials for arsenic adsorption to prevent arsenic air pollution from arseniccontaminated soils.

  18. Current Status and Prevention Strategy for Coal-arsenic Poisoning in Guizhou, China

    OpenAIRE

    Li, Dasheng; An, Dong; Zhou, Yunsu; Liu, Jie; Waalkes, Michael P.

    2006-01-01

    Arsenic exposure from burning coal with high arsenic contents occurs in southwest Guizhou, China. Coal in this region contains extremely high concentrations of inorganic arsenic. Arsenic exposure from coal-burning is much higher than exposure from arsenic-contaminated water in other areas of China. The current status and prevention strategies for arsenic poisoning from burning high-arsenic coal in southwest Guizhou, China, is reported here. Over 3,000 arsenic-intoxicated patients were diagnos...

  19. Another Look at the Mechanisms of Hydride Transfer Enzymes from Quantum and Classical Transition Path Sampling

    Science.gov (United States)

    Dzierlenga, Michael; Antoniou, Dimitri; Schwartz, Steven

    2015-03-01

    The mechanisms involved in enzymatic hydride transfer have been studies for years but questions remain, due to the difficulty in determining the participation of protein dynamics and quantum effects, especially hydrogen tunneling. In this study, we use transition path sampling (TPS) with normal mode centroid molecular dynamics (CMD) to calculate the barrier to hydride transfer in yeast alcohol dehydrogenase (YADH) and lactate dehydrogenase (LDH). Calculation of the work applied to the hydride during the reaction allows for observation of the change in barrier height due to inclusion of quantum effects. Additionally, the same calculations were performed using deuterium as the transferring particle to validate our methods with experimentally measured kinetic isotope effects. The change in barrier height in YADH upon inclusion of quantum effects is indicative of a zero-point energy contribution, and is evidence that the protein mediates a near-barrierless transfer of the rate-limiting hydride. Calculation of kinetic isotope effects using the average difference in barrier between hydride and deuteride agreed well with experimental results. The authors acknowledge the support of the National Institutes of Health Grants GM068036 and GM102226.

  20. Hydrogen transmission/storage with a metal hydride/organic slurry

    Energy Technology Data Exchange (ETDEWEB)

    Breault, R.W.; Rolfe, J.; McClaine, A. [Thermo Power Corp., Waltham, MA (United States)

    1998-08-01

    Thermo Power Corporation has developed a new approach for the production, transmission, and storage of hydrogen. In this approach, a chemical hydride slurry is used as the hydrogen carrier and storage media. The slurry protects the hydride from unanticipated contact with moisture in the air and makes the hydride pumpable. At the point of storage and use, a chemical hydride/water reaction is used to produce high-purity hydrogen. An essential feature of this approach is the recovery and recycle of the spent hydride at centralized processing plants, resulting in an overall low cost for hydrogen. This approach has two clear benefits: it greatly improves energy transmission and storage characteristics of hydrogen as a fuel, and it produces the hydrogen carrier efficiently and economically from a low cost carbon source. The preliminary economic analysis of the process indicates that hydrogen can be produced for $3.85 per million Btu based on a carbon cost of $1.42 per million Btu and a plant sized to serve a million cars per day. This compares to current costs of approximately $9.00 per million Btu to produce hydrogen from $3.00 per million Btu natural gas, and $25 per million Btu to produce hydrogen by electrolysis from $0.05 per Kwh electricity. The present standard for production of hydrogen from renewable energy is photovoltaic-electrolysis at $100 to $150 per million Btu.