WorldWideScience

Sample records for heavy-metal tungsten alloy

  1. Pulmonary toxicity after exposure to military-relevant heavy metal tungsten alloy particles

    International Nuclear Information System (INIS)

    Roedel, Erik Q.; Cafasso, Danielle E.; Lee, Karen W.M.; Pierce, Lisa M.

    2012-01-01

    Significant controversy over the environmental and public health impact of depleted uranium use in the Gulf War and the war in the Balkans has prompted the investigation and use of other materials including heavy metal tungsten alloys (HMTAs) as nontoxic alternatives. Interest in the health effects of HMTAs has peaked since the recent discovery that rats intramuscularly implanted with pellets containing 91.1% tungsten/6% nickel/2.9% cobalt rapidly developed aggressive metastatic tumors at the implantation site. Very little is known, however, regarding the cellular and molecular mechanisms associated with the effects of inhalation exposure to HMTAs despite the recognized risk of this route of exposure to military personnel. In the current study military-relevant metal powder mixtures consisting of 92% tungsten/5% nickel/3% cobalt (WNiCo) and 92% tungsten/5% nickel/3% iron (WNiFe), pure metals, or vehicle (saline) were instilled intratracheally in rats. Pulmonary toxicity was assessed by cytologic analysis, lactate dehydrogenase activity, albumin content, and inflammatory cytokine levels in bronchoalveolar lavage fluid 24 h after instillation. The expression of 84 stress and toxicity-related genes was profiled in lung tissue and bronchoalveolar lavage cells using real-time quantitative PCR arrays, and in vitro assays were performed to measure the oxidative burst response and phagocytosis by lung macrophages. Results from this study determined that exposure to WNiCo and WNiFe induces pulmonary inflammation and altered expression of genes associated with oxidative and metabolic stress and toxicity. Inhalation exposure to both HMTAs likely causes lung injury by inducing macrophage activation, neutrophilia, and the generation of toxic oxygen radicals. -- Highlights: ► Intratracheal instillation of W–Ni–Co and W–Ni–Fe induces lung inflammation in rats. ► W–Ni–Co and W–Ni–Fe alter expression of oxidative stress and toxicity genes. ► W

  2. In vitro profiling of epigenetic modifications underlying heavy metal toxicity of tungsten-alloy and its components

    International Nuclear Information System (INIS)

    Verma, Ranjana; Xu, Xiufen; Jaiswal, Manoj K.; Olsen, Cara; Mears, David; Caretti, Giuseppina; Galdzicki, Zygmunt

    2011-01-01

    Tungsten-alloy has carcinogenic potential as demonstrated by cancer development in rats with intramuscular implanted tungsten-alloy pellets. This suggests a potential involvement of epigenetic events previously implicated as environmental triggers of cancer. Here, we tested metal induced cytotoxicity and epigenetic modifications including H3 acetylation, H3-Ser10 phosphorylation and H3-K4 trimethylation. We exposed human embryonic kidney (HEK293), human neuroepithelioma (SKNMC), and mouse myoblast (C2C12) cultures for 1-day and hippocampal primary neuronal cultures for 1-week to 50-200 μg/ml of tungsten-alloy (91% tungsten/6% nickel/3% cobalt), tungsten, nickel, and cobalt. We also examined the potential role of intracellular calcium in metal mediated histone modifications by addition of calcium channel blockers/chelators to the metal solutions. Tungsten and its alloy showed cytotoxicity at concentrations > 50 μg/ml, while we found significant toxicity with cobalt and nickel for most tested concentrations. Diverse cell-specific toxic effects were observed, with C2C12 being relatively resistant to tungsten-alloy mediated toxic impact. Tungsten-alloy, but not tungsten, caused almost complete dephosphorylation of H3-Ser10 in C2C12 and hippocampal primary neuronal cultures with H3-hypoacetylation in C2C12. Dramatic H3-Ser10 dephosphorylation was found in all cobalt treated cultures with a decrease in H3 pan-acetylation in C2C12, SKNMC and HEK293. Trimethylation of H3-K4 was not affected. Both tungsten-alloy and cobalt mediated H3-Ser10 dephosphorylation were reversed with BAPTA-AM, highlighting the role of intracellular calcium, confirmed with 2-photon calcium imaging. In summary, our results for the first time reveal epigenetic modifications triggered by tungsten-alloy exposure in C2C12 and hippocampal primary neuronal cultures suggesting the underlying synergistic effects of tungsten, nickel and cobalt mediated by changes in intracellular calcium homeostasis and

  3. Tungsten heavy metal alloys relations between the crystallographic texture and the internal stress distribution

    International Nuclear Information System (INIS)

    Nicolas, G.; Voltz, M.

    2001-01-01

    Quite often the W-Ni-Fe-Co heavy alloys are subjected to a thermomechanical processing of swaging and aging in order to obtain the highest possible level of resistance. Within the framework of this plastic deformation on cylindrical parts, the swaging leads to the distribution of morphological and crystallographic texture as well as specific internal stresses. The resulting mechanical characteristics are correlated to structural and sub-structural variations. (author)

  4. In-situ field-ion microscope study of the recovery behavior of heavy metal ion-irradiated tungsten, tungsten (rhenium) alloys and molybdenum

    International Nuclear Information System (INIS)

    Nielsen, C.H.

    1977-06-01

    Three field ion microscope (FIM) experiments were carried out to study the annealing behavior of heavy ion irradiated tungsten, tungsten (rhenium) alloys and molybdenum. The first experiment dealt with the stage I long-range migration of tungsten self interstitial atoms (SIAs) in high purity tungsten of resistivity ratio, R = 24,000 (R = rho 300 /rho 4 . 2 , where rho 300 and rho 4 . 2 are the room temperature and 0 0 C resistivities). The FIM specimens were irradiated in situ at 18 K with 30 keV W + ions to an average dose of 5 x 10 12 ions cm -2 and subsequently examined by the pulsed-field evaporation technique. The second experiment dealt with the phenomenon of impurity atom trapping of SIAs during long-range migration. It was shown that rhenium atoms in a tungsten matrix tend to capture tungsten SIAs and remain bound up to temperatures as high as 390 K. The final experiment was concerned with the low temperature annealing kinetics of irradiated molybdenum. High purity molybdenum of resistivity ratio R = 5700 was irradiated at 10 K with 30 keV Mo + ions to a dose of approximately 5 x 10 12 ions cm -2 . The results indicated that the electric field has only a minimal effect on the SIA annealing kinetics. This tends to strengthen the contention that the molybdenum SIA becomes mobile at 32 K

  5. Tungsten Alloy Outgassing Measurements

    CERN Document Server

    Rutherfoord, John P; Shaver, L

    1999-01-01

    Tungsten alloys have not seen extensive use in liquid argon calorimeters so far. Because the manufacturing process for tungsten is different from the more common metals used in liquid argon there is concern that tungsten could poison the argon thereby creating difficulties for precision calorimetry. In this paper we report measurements of outgassing from the tungsten alloy slugs proposed for use in the ATLAS FCal module and estimate limits on potential poisoning with reasonable assumptions. This estimate gives an upper limit poisoning rate of tungsten slugs.

  6. Tungsten and other heavy metal contamination in aquatic environments receiving wastewater from semiconductor manufacturing

    International Nuclear Information System (INIS)

    Hsu, Shih-Chieh; Hsieh, Hwey-Lian; Chen, Chang-Po; Tseng, Chun-Mao; Huang, Shou-Chung; Huang, Chou-Hao; Huang, Yi-Tang; Radashevsky, Vasily; Lin, Shuen-Hsin

    2011-01-01

    Through analyses of water and sediments, we investigate tungsten and 14 other heavy metals in a stream receiving treated effluents from a semiconductor manufacturer-clustered science park in Taiwan. Treated effluents account for ∼50% of total annual river discharge and <1% of total sediment discharge. Dissolved tungsten concentrations in the effluents abnormally reach 400 μg/L, as compared to the world river average concentration of <0.1 μg/L. Particulate tungsten concentrations are up to 300 μg/g in suspended and deposited sediments, and the corresponding enrichment factors are three orders of magnitude higher than average crust composition. Surprisingly, the estimated amount of tungsten exported to the adjacent ocean is 23.5 t/yr, which can approximate the amount from the Yangtze River should it be unpolluted. This study highlights the urgency of investigating the biological effect of such contamination.

  7. Tungsten and tungsten alloys by powder metallurgy

    International Nuclear Information System (INIS)

    Belhadjhamida, A.; German, R.M.

    1991-01-01

    Tungsten has a historical link with powder metallurgy and there is continued progress in expanding the available compositions and processing options. This paper starts with an introduction to the history of tungsten powder metallurgy and use this as a basis for analyzing some of the current trends. The literature base in tungsten processing is expanding and includes new alloys, microstructures, and processing routes. A few examples will be emphasize here to produce a frame work for this program, including description of sintering mechanisms for tungsten, liquid phase sintering advances, hot consolidation fundamentals, and options for complex shaping using powder injection modeling. For this base, subsequent presentations will expand on these fundamental advances

  8. SINTERED REFRACTORY TUNGSTEN ALLOYS. Gesinterte hochschmelzende wolframlegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, R.; Sedlatschek, K.; Braun, H.

    1971-12-15

    Dependence of the melting point of the refractory metals on their positions in the periodic system - alloys of tungsten with other refractory metals - sintering of the alloys - processing of the alloys - technological properties.

  9. Strain aging in tungsten heavy alloys

    International Nuclear Information System (INIS)

    Dowding, R.J.; Tauer, K.J.

    1991-01-01

    This paper reports on tungsten heavy alloys which are two-phase mixtures of body center cubic (BCC) tungsten surrounded by a face center cubic (FCC) matrix. The matrix is most often composed of nickel and iron in a ratio of 70:30 but, occasionally, the matrix may also contain cobalt or copper. Nickel, however, is always the primary matrix component. The tungsten heavy alloy is fabricated through powder metallurgy techniques. Elemental powders are blended, pressed to shape, and sintered. Depending upon the tungsten content, the sintering temperatures are usually in the range of 1450 degrees C to 1525 degrees C. These temperatures are high enough that, as a result, the matrix is at the liquid phase and the process is known as liquid phase sintering. At the liquid phase temperature, the matrix becomes saturated with tungsten, but this does not change the FCC character of the matrix. The sintering is usually done in a hydrogen atmosphere furnace in order to reduce the oxides on the tungsten powder surfaces and create clean, active surfaces which will enhance the adherence between the tungsten and the matrix. The hydrogen atmosphere also creates the presence of excess dissolved hydrogen in the alloy. It has been shown that the hydrogen degrades the toughness and ductility of the heavy alloy. A post-sintering vacuum heat treatment is generally required to insure that there is no residual hydrogen present. The as-sintered tensile strength of a 90% tungsten, 7% nickel, 3% iron alloy (90W) is in the range of 800 to 940 MPa and can be increased significantly by cold working, usually rolling or swaging. Swaging to reductions in area of 20% can result in tensile strengths of 1250 MPa or more. As the strength increases, the elongation, which may have been 30% or more, decreases to less than 5%

  10. Characterization of plasma coated tungsten heavy alloy

    International Nuclear Information System (INIS)

    Bose, A.; Kapoor, D.; Lankford, J. Jr.; Nicholls, A.E.

    1996-01-01

    The detrimental environmental impact of Depleted Uranium-based penetrators have led to tremendous development efforts in the area of tungsten heavy alloy based penetrators. One line of investigation involves the coating of tungsten heavy alloys with materials that are prone to shear localization. Plasma spraying of Inconel 718 and 4340 steel have been used to deposit dense coatings on tungsten heavy alloy substrates. The aim of the investigation was to characterize the coating primarily in terms of its microstructure and a special push-out test. The paper describes the results of the push-out tests and analyzes some of the possible failure mechanisms by carrying out microstructural characterization of the failed rings obtained from the push out tests

  11. Potentiometric determination of the tungsten content of tantalum-tungsten alloys with chromium II

    International Nuclear Information System (INIS)

    Gavra, Z.; Ronen, S.; Levin, R.

    1977-05-01

    A method was developed for the potentiometric determination of the tungsten content of tantalum-tungsten alloys of different compositions. These were dissolved under conditions that enabled the tungsten content to be determined with chromium (II). Phosphoric acid was selected as a suitable complexing agent for the prevention of the precipitation of tungsten and tantalum compounds. The use of chromium (II) required an oxygen-tight system and therefore the work was carried out in suitable vessels for storage and tritation

  12. Serrated flow behavior in tungsten heavy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Das, Jiten, E-mail: das.jiten@gmail.com; Sankaranarayana, M.; Nandy, T.K.

    2015-10-14

    Flow behavior of a tungsten heavy alloy of composition, 90.5 wt% W–7.1 wt% Ni–1.65 wt% Fe–0.5 wt% Co–0.25 wt% Mo was investigated in a temperature range of 223–973 K and strain rate range of 10{sup −5}–10{sup −2} s{sup −1}. In the temperature range of 773–873 K, the stress strain curves were characterized by jerky flow pointing towards Dynamic Strain Ageing (DSA)/Portevin Le-Chatelier's (PLC) effect. Characteristics of DSA were analyzed in detail. Based on the value of activation energy determined from the critical strain method, diffusion of interstitials (carbon, oxygen, nitrogen and hydrogen) were thought to be responsible for the DSA effect. The results were discussed in relation to information existing in this area in tungsten heavy alloys. The study of fracture surface of tensile tested samples (in the range of 823–973 K) showed that the fractographic features, mostly intergranular, predominantly govern the overall ductility of the alloy and do not change except for surface oxidation at relatively higher temperatures.

  13. Corrosion of high-density sintered tungsten alloys

    International Nuclear Information System (INIS)

    Batten, J.J.; Moore, B.T.

    1989-01-01

    In comparative corrosion tests, the corrosion resistance of an Australian tungsten alloy (95% W, 3.5% Ni, 1.5% Fe) was found to be superior to three other tungsten alloys and, under certain conditions, even more corrosion-resistant than pure tungsten. Corrosion resistance was evaluated after immersion in both distilled water and 5% sodium chloride solutions, and in cyclic humidity and salt mist environments. For all but the Australian alloy, the rate of corrosion in sodium chloride solution was markedly less than that in distilated water. In all cases, alloys containing copper had the greatest corrosion rates. Corrosion mechanisms were investigated using a scanning electron microscope, analysis of corrosion products and galvanic corrosion studies. For the alloys, corrosion was attributed primarily to a galvanic reaction. Whether the tungsten or binder phase of the alloy became anodic, and thus was attacked preferentially, depended upon alloy composition and corrosion environment. 16 refs., 4 tabs., 4 figs

  14. Advanced smart tungsten alloys for a future fusion power plant

    Science.gov (United States)

    Litnovsky, A.; Wegener, T.; Klein, F.; Linsmeier, Ch; Rasinski, M.; Kreter, A.; Tan, X.; Schmitz, J.; Mao, Y.; Coenen, J. W.; Bram, M.; Gonzalez-Julian, J.

    2017-06-01

    The severe particle, radiation and neutron environment in a future fusion power plant requires the development of advanced plasma-facing materials. At the same time, the highest level of safety needs to be ensured. The so-called loss-of-coolant accident combined with air ingress in the vacuum vessel represents a severe safety challenge. In the absence of a coolant the temperature of the tungsten first wall may reach 1200 °C. At such a temperature, the neutron-activated radioactive tungsten forms volatile oxide which can be mobilized into atmosphere. Smart tungsten alloys are being developed to address this safety issue. Smart alloys should combine an acceptable plasma performance with the suppressed oxidation during an accident. New thin film tungsten-chromium-yttrium smart alloys feature an impressive 105 fold suppression of oxidation compared to that of pure tungsten at temperatures of up to 1000 °C. Oxidation behavior at temperatures up to 1200 °C, and reactivity of alloys in humid atmosphere along with a manufacturing of reactor-relevant bulk samples, impose an additional challenge in smart alloy development. First exposures of smart alloys in steady-state deuterium plasma were made. Smart tungsten-chroimium-titanium alloys demonstrated a sputtering resistance which is similar to that of pure tungsten. Expected preferential sputtering of alloying elements by plasma ions was confirmed experimentally. The subsequent isothermal oxidation of exposed samples did not reveal any influence of plasma exposure on the passivation of alloys.

  15. Heavy metal jako subkultura

    OpenAIRE

    KOUTNÁ, Daniela

    2016-01-01

    This bachelor thesis deals with heavy metal subculture. Its aim is to introduce the most important branches and to show broadness of heavy metal. This bachelor thesis describes development and history, briefly shows Czech heavy metal history alongside with the biggest and most popular Czech heavy metal festivals. It shows the most dressing concerns of society against this style.

  16. Corrosion of high-density sintered tungsten alloys. Part 2

    International Nuclear Information System (INIS)

    Batten, J.J.; Moore, B.T.

    1988-12-01

    The behaviour of four high-density sintered tungsten alloys has been evluated and compared with that of pure tungsten. Rates of corrosion during the cyclic humidity and the salt mist tests were ascertained from weight loss measurements. Insight into the corrosion mechanism was gained from the nature of the corrosion products and an examination of the corroded surfaces. In the tests, the alloy 95% W, 2.5% Ni, 1.5% Fe was the most corrosion resistant. The data showed that copper as an alloying element accelerates corrosion of tungsten alloys. Both attack on the tungsten particles and the binder phase were observed together with tungsten grain loss. 6 refs., 3 tabs.,

  17. Carcinogenicity and Immnotoxicity of Embedded Depleted Uranium and Heavy-Metal Tungsten Alloy in Rodents

    National Research Council Canada - National Science Library

    Miller, Alexandra

    2002-01-01

    .... We hypothesize that long-term chronic exposure to embedded DU and HMTA initiates changes in normal immune function that will eventually result in a carcinogenic response characterized by both tumor...

  18. Carcinogenicity and Immunotoxicity of Embedded Depleted Uranium and Heavy-Metal Tungsten Alloy in Rodents

    Science.gov (United States)

    2006-10-01

    collected and passed through a column packed with Amberlite XAD-8 resin. Resins were purified by Soxhlet -extraction before use. Use of these columns...complete culture medium. To assay for NK function, serial dilutions of the splenocyte suspension were done to yield splenocyte/target cell ratios of 200:1...and Maenza 1976; Sunderman et al. 1977). Tumors (rhabdomyosarcoma and fibrosar- coma) were found in many cases at the injec- tion site, with tumor yield

  19. Microstructural study of tungsten influence on Co-Cr alloys

    International Nuclear Information System (INIS)

    Karaali, A.; Mirouh, K.; Hamamda, S.; Guiraldenq, P.

    2005-01-01

    Alloying elements, such as W, Mo, Mn,..., are of a great importance in the preoxidation of dental alloys and, consequently, on the ceramic/metal bond quality. This study deals with the effect of tungsten addition on the microstructural state of Co-Cr dental alloys, before the ceramisation process. These materials were prepared by unidirectional solidification. Their characterization has been carried out, using transmission electron microscopy (TEM) and X-ray diffraction. It shows that the addition of tungsten up to 8 wt.% induces structural transformations, which are believed to be linked to the added amount of tungsten

  20. High temperature diffusion of hafnium in tungsten and a tungsten-hafnium carbide alloy

    International Nuclear Information System (INIS)

    Ozaki, Y.; Zee, R.H.

    1994-01-01

    Refractory metals and ceramics are used extensively in energy systems due to their high temperature properties. This is particularly important in direct conversion systems where thermal to electric conversion efficiency is a direct function of temperature. Tungsten, which has the highest melting temperature among elemental metals, does not possess sufficient creep resistance at temperature above 1,600 K. Different dispersion strengthened tungsten alloys have been developed to extend the usefulness of tungsten to higher temperatures. One of these alloys, tungsten with 0.4 mole percent of finely dispersed HfC particles (W-HfC), has the optimum properties for high temperature applications. Hafnium carbide is used as the strengthening agent due to its high chemical stability and its compatibility with tungsten. The presence of HfC particles retards the rate of grain growth as well as restricting dislocation motion. Both of which are beneficial for creep resistance. The long term behavior of this alloy depends largely on the evolution of its microstructure which is governed by the diffusion of its constituents. Data on the diffusion of carbon in tungsten and tungsten self-diffusion are available, but no direct measurements have been made on the diffusion of hafnium in tungsten. The only diffusion data available are estimated from a coarsening study and these data are highly unreliable. In this study, the diffusion behavior of hafnium in pure tungsten and in a W-HfC alloy was directly measured by means of Secondary Ion Mass Spectroscopy (SIMS). The selection of the W-HfC alloy is due to its importance in high temperature engineering applications, and its higher recrystallization temperature. The presence of HfC particles in tungsten restricts grain growth resulting in better high temperature creep resistance. The higher recrystallization temperature allows measurements to be made over a wider range of temperatures at a relatively constant grain size

  1. Corrosion of high-density sintered tungsten alloys. Part 1

    International Nuclear Information System (INIS)

    Batten, J.J.; McDonald, I.G.; Moore, B.T.; Silva, V.M.

    1988-10-01

    The corrosion behaviour of four tungsten alloys has been evaluated through weight loss measurements after total immersion in both distilled water insight into the mechanism of corrosion was afforded by an examination of the and 5% sodium chloride solutions. Some insight the mechanism of corrosion was afforded by using the Scanning Electron Microscopy and through an analysis of the corrosion products. Pure tungsten and all the alloys studied underwent corrosion during the tests, and in each case the rare of corrosion in sodium chloride solution was markedly less than that in distilled water. A 95% W, 3.5% Ni, 1.5% Fe alloy was found to be the most corrosion resistant of the alloys under the experimental conditions. Examination of the data shows that for each of the tests, copper as an alloying element accelerates corrosion of tungsten alloys. 9 refs., 7 tabs., 12 figs

  2. Tungsten alloy research at the US Army Materials Technology Laboratory

    International Nuclear Information System (INIS)

    Dowding, R.J.

    1991-01-01

    This paper reports that recent research into tungsten heavy alloys at the U. S. Army Materials Technology Laboratory (MTL) has explored many areas of processing and process development. The recrystallization and respheroidization of tungsten grains in a heavily cold worked heavy alloy has been examined and resulted in the identification of a method of grain refinement. Another area of investigation has been lightly cold worked. It was determined that it was possible to increase the strength and hardness of the tungsten grains by proper hat treatment. MTL has been involved in the Army's small business innovative research (SBIR) program and several programs have been funded. Included among these are a method of coating the tungsten powders with the alloying elements and the development of techniques of powder injection molding of heavy alloys

  3. Discontinuous precipitation in cobalt-tungsten alloys

    International Nuclear Information System (INIS)

    Zieba, P.; Cliff, G.; Lorimer, G.W.

    1997-01-01

    Discontinuous precipitation in a Co32 wt% W alloy aged in the temperature range from 875 K to 1025 K has been investigated. Philips EM 430 STEM has been used to characterize the microstructure and to measure the composition profiles across individual lamellae of ε Co and Co 3 W phases in partially transformed specimens. Two kinds of cellular precipitates have been found in the alloy. The initial transformation product, identified as primary lamellae with spacing of a few nanometers is replaced during prolonged ageing by secondary lamellae with a much larger interlamellar spacing, typically a few tens of nm. Line scans across cell boundaries of the primary lamellae revealed that, just behind the advancing cell boundary, the solute content is far from the equilibrium state. This solute excess within the cells is quickly removed at the ageing temperature. Calculations show that the diffusion process was too rapid to be identified as ordinary volume diffusion. Investigation of the kinetics showed that discontinuous precipitation is controlled by diffusion processes at the advancing cell boundary. This proposal has been confirmed by STEM analysis of tungsten profiles in the depleted ε Co lamellae

  4. Volatility from copper and tungsten alloys for fusion reactor applications

    International Nuclear Information System (INIS)

    Smolik, G.R.; Neilson, R.M. Jr.; Piet, S.J.

    1989-01-01

    Accident scenarios for fusion power plants present the potential for release and transport of activated constituents volatilized from first wall and structural materials. The extent of possible mobilization and transport of these activated species, many of which are ''oxidation driven'', is being addressed by the Fusion Safety Program at the Idaho National Engineering Laboratory (INEL). This report presents experimental measurements of volatilization from a copper alloy in air and steam and from a tungsten alloy in air. The major elements released included zinc from the copper alloy and rhenium and tungsten from the tungsten alloy. Volatilization rates of several constituents of these alloys over temperatures ranging from 400 to 1200 degree C are presented. These values represent release rates recommended for use in accident assessment calculations. 8 refs., 3 figs., 5 tabs

  5. High strength tungsten heavy alloys with molybdenum additions

    International Nuclear Information System (INIS)

    Bose, A.; Sims, D.M.; German, R.M.

    1987-01-01

    Tungsten heavy alloys are candidates for numerous applications based on the unique combination of high density, high strength, and high ductility coupled with excellent machinability. Though there has been considerable research on heavy alloys, the primary focus has been on the ductility. These alloys are well suited for ballistic uses due to their high densities and it is expected that for superior ballistic performance, a high hardness, high strength and moderate ductility alloy would be ideal. The major goal of this investigation was to obtain heavy alloys with hardness greater than HRA 72. It is evident from the phase diagrams that molybdenum, which goes into solution in tungsten, nickel and iron, could act as a potential strengthening addition. With this in view, tungsten heavy alloys with molybdenum additions were fabricated from mixed elemental powders. A baseline composition of 90W-7Ni-3Fe was chosen to its good elongation and moderate strength. The molybdenum additions were made by replacing the tungsten. Compared to the baseline properties with no molybdenum addition, the strength and hardness showed a continuous increase with molybdenum addition. The ductility of the alloy continued to decrease with increasing molybdenum content, but even with 16% wt. % molybdenum of the elongation was still around 6%. An interesting facet of these alloying additions is the grain refinement that is brought about by adding to molybdenum to the system. The grain refinement is related to the lower solubility of tunbsten in the matrix due to partial displacement by molybdenum

  6. A review of chromium, molybdenum, and tungsten alloys

    International Nuclear Information System (INIS)

    Klopp, W.D.

    1975-01-01

    The mechanical properties of chromium, molybdenum, and tungsten alloys are reviewed, with particular emphasis on high-temperature strength and low-temperature ductility. Precipitate strengthening is highly effective at 0.4-0.8 Tsub(m) in these metals, with HfC being most effective in tungsten and molybdenum, and Ta(B,C) most effective in chromium. Low-temperature ductility can be improved by alloying to promote rhenium ductilizing or solution softening. The low-temperature mechanical properties of these alloys appear related to electronic interactions rather than to the usual metallurgical considerations. (Auth.)

  7. Ductile tungsten-nickel alloy and method for making same

    Science.gov (United States)

    Snyder, Jr., William B.

    1976-01-01

    The present invention is directed to a ductile, high-density tungsten-nickel alloy which possesses a tensile strength in the range of 100,000 to 140,000 psi and a tensile elongation of 3.1 to 16.5 percent in 1 inch at 25.degree.C. This alloy is prepared by the steps of liquid phase sintering a mixture of tungsten-0.5 to 10.0 weight percent nickel, heat treating the alloy at a temperature above the ordering temperature of approximately 970.degree.C. to stabilize the matrix phase, and thereafter rapidly quenching the alloy in a suitable liquid to maintain the matrix phase in a metastable, face-centered cubic, solid- solution of tungsten in nickel.

  8. Soil heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Sherameti, Irena [Jena Univ. (Germany). Inst. fuer Allgemeine Botanik und Pflanzenphysiologie; Varma, Ajit (eds.) [Amity Univ., Uttar Pradesh (India). Amity Inst. of Microbial Technology; Amity Science, Technology and Innovation Foundation, Noida, UP (India)

    2010-07-01

    Human activities have dramatically changed the composition and organisation of soils. Industrial and urban wastes, agricultural application and also mining activities resulted in an increased concentration of heavy metals in soils. How plants and soil microorganisms cope with this situation and the sophisticated techniques developed for survival in contaminated soils is discussed in this volume. The topics presented include: the general role of heavy metals in biological soil systems; the relation of inorganic and organic pollutions; heavy metal, salt tolerance and combined effects with salinity; effects on abuscular mycorrhizal and on saprophytic soil fungi; heavy metal resistance by streptomycetes; trace element determination of environmental samples; the use of microbiological communities as indicators; phytostabilization of lead polluted sites by native plants; effects of soil earthworms on removal of heavy metals and the remediation of heavy metal contaminated tropical land. (orig.)

  9. Ductile tungsten-nickel-alloy and method for manufacturing same

    Science.gov (United States)

    Ludwig, Robert L.

    1978-01-01

    The tensile elongation of a tungsten-nickel-iron alloy containing essentially 95 weight percent reprocessed tungsten, 3.5 weight percent nickel, and 1.5 weight percent iron is increased from a value of less than about 1 percent up to about 23 percent by the addition of less than 0.5 weight percent of a reactive metal consisting of niobium and zirconium.

  10. The influence of Fe content on spreading ability of tungsten heavy alloys matrix on tungsten surface

    Directory of Open Access Journals (Sweden)

    A. Krzyńska

    2011-07-01

    Full Text Available The results of experimental study of tungsten spreading ability with W-Ni-Co-Fe matrix are presented. The aim of these investigations was to see how Fe concentration in W – Ni – Co matrix influences the wettability of tungsten grains during liquid phase sintering. Four green compact specimens containing 50%W, 10%Co and Ni + Fe = 40% but with different Ni to Fe ratio were prepared. The cylindrical specimen 5mm diameter and 5mm height were put on clean pure tungsten substrate and then 20 minutes heated at 1520oC in hydrogen atmosphere. After heating the specimens were carefully measured and then the specimens for structure observations were prepared. It was concluded, that increase of Fe content decrease the melting temperature of W – Ni – Co alloy. The melting point decrease caused by Fe content increase substantially the spreading ability of tungsten substrate with W – Ni – Co alloy. Metallography investigations showed some microstructure changes in “reaction zone” identified in tungsten substrate – (WNi40-xCo10Fex interface. The results of the study confirmed our earlier observations that even relative small Fe addition promotes Weight Heavy Alloys (WHA liquid phase sintering.

  11. Fabrication of tungsten wire reinforced nickel-base alloy composites

    Science.gov (United States)

    Brentnall, W. D.; Toth, I. J.

    1974-01-01

    Fabrication methods for tungsten fiber reinforced nickel-base superalloy composites were investigated. Three matrix alloys in pre-alloyed powder or rolled sheet form were evaluated in terms of fabricability into composite monotape and multi-ply forms. The utility of monotapes for fabricating more complex shapes was demonstrated. Preliminary 1093C (2000F) stress rupture tests indicated that efficient utilization of fiber strength was achieved in composites fabricated by diffusion bonding processes. The fabrication of thermal fatigue specimens is also described.

  12. Titrimetric determination of tungsten in its alloys with tantalum

    International Nuclear Information System (INIS)

    Elinson, S.V.; Nezhnova, T.I.

    1982-01-01

    Titrimetric method of tungsten determination in tantalum base alloys has been developed. The method permits to determine 5-10% tungsten in the alloys with relative standard deviation of 0.013. The conditions are created by application of precipitation from homogeieous solutions or by the method of appearing reagents at pH values, which condition gradual hydrolytic precipitation of tantalum, and sodium tungstate remains in the solution and is not sorbed on tantalum hydroxide. After separation of tantalum oxide tungsten is precipitated in the form of lead tungstate by the excess of ti trated solution of lead salt during boiling and then at the background of lead tungstate precipitate without its separation lead excess is titrated by EDTA in the presence of mixed indicator-4-(2-pyridylazo)resocinol and xylenole orange in acetate buffer solution

  13. Molecular basis of carcinogenicity of tungsten alloy particles

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Robert M.; Williams, Tim D.; Waring, Rosemary H.; Hodges, Nikolas J., E-mail: n.hodges@bham.ac.uk

    2015-03-15

    The tungsten alloy of 91% tungsten, 6% nickel and 3% cobalt (WNC 91–6–3) induces rhabdomyosarcoma when implanted into a rat thigh muscle. To investigate whether this effect is species-specific human HSkMc primary muscle cells were exposed to WNC 91–6–3 particles and responses were compared with those from a rat skeletal muscle cell line (L6-C11). Toxicity was assessed by the adenylate kinase assay and microscopy, DNA damage by the Comet assay. Caspase 3 enzyme activity was measured and oligonucleotide microarrays were used for transcriptional profiling. WNC 91–6–3 particles caused toxicity in cells adjacent to the particles and also increased DNA strand breaks. Inhibition of caspase 3 by WNC 91–6–3 occurred in rat but not in human cells. In both rat and human cells, the transcriptional response to WNC 91–6–3 showed repression of transcripts encoding muscle-specific proteins with induction of glycolysis, hypoxia, stress responses and transcripts associated with DNA damage and cell death. In human cells, genes encoding metallothioneins were also induced, together with genes related to angiogenesis, dysregulation of apoptosis and proliferation consistent with pre-neoplastic changes. An alloy containing iron, WNF 97–2–1, which is non-carcinogenic in vivo in rats, did not show these transcriptional changes in vitro in either species while the corresponding cobalt-containing alloy, WNC 97–2–1 elicited similar responses to WNC 91–6–3. Tungsten alloys containing both nickel and cobalt therefore have the potential to be carcinogenic in man and in vitro assays coupled with transcriptomics can be used to identify alloys, which may lead to tumour formation, by dysregulation of biochemical processes. - Highlights: • Use of transcriptomics to identify likely carcinogenic tungsten alloys in vitro • Cobalt containing alloys cause oxidative stress, DNA-damage and perturb apoptosis. • Presence of cobalt causes changes in gene expression

  14. Simulating evaporation of surface atoms of thorium-alloyed tungsten in strong electronic fields

    International Nuclear Information System (INIS)

    Bochkanov, P.V.; Mordyuk, V.S.; Ivanov, Yu.I.

    1984-01-01

    By the Monte Carlo method simulating evaporation of surface atoms of thorium - alloyed tungsten in strong electric fields is realized. The strongest evaporation of surface atoms of pure tungsten as compared with thorium-alloyed tungsten in the contentration range of thorium atoms in tungsten matrix (1.5-15%) is shown. The evaporation rate increases with thorium atoms concentration. Determined is in relative units the surface atoms evaporation rate depending on surface temperature and electric field stront

  15. Gas-driven permeation of deuterium through tungsten and tungsten alloys

    Energy Technology Data Exchange (ETDEWEB)

    Buchenauer, Dean A., E-mail: dabuche@sandia.gov [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States); Karnesky, Richard A. [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States); Fang, Zhigang Zak; Ren, Chai [University of Utah, Department of Metallurgical Engineering, Salt Lake City, UT 84112 (United States); Oya, Yasuhisa [Shizuoka University, Graduate School of Science, Shizuoka (Japan); Otsuka, Teppei [Kyushu University, Department of Advanced Energy Engineering Science, Fukuoka (Japan); Yamauchi, Yuji [Hokkaido University, Third Division of Quantum Science and Engineering, Faculty of Engineering, Sapporo (Japan); Whaley, Josh A. [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States)

    2016-11-01

    Highlights: • We have designed and performed initial studies on a high temperature gas-driven permeation cell capable of operating at temperatures up to 1150 °C and at pressures between 0.1–1 atm. • Permeation measurements on ITER grade tungsten compare well with past studies by Frauenfelder and Zahkarov in the temperature range from 500 to 1000 °C. • First permeation measurements on Ti dispersoid-strengthened ultra-fine grained tungsten show higher permeation at 500 °C, but very similar permeation with ITER tungsten at 1000 °C. Diffusion along grain boundaries may be playing a role for this type of material. - Abstract: To address the transport and trapping of hydrogen isotopes, several permeation experiments are being pursued at both Sandia National Laboratories (deuterium gas-driven permeation) and Idaho National Laboratories (tritium gas- and plasma-driven tritium permeation). These experiments are in part a collaboration between the US and Japan to study the performance of tungsten at divertor relevant temperatures (PHENIX). Here we report on the development of a high temperature (≤1150 °C) gas-driven permeation cell and initial measurements of deuterium permeation in several types of tungsten: high purity tungsten foil, ITER-grade tungsten (grains oriented through the membrane), and dispersoid-strengthened ultra-fine grain (UFG) tungsten being developed in the US. Experiments were performed at 500–1000 °C and 0.1–1.0 atm D{sub 2} pressure. Permeation through ITER-grade tungsten was similar to earlier W experiments by Frauenfelder (1968–69) and Zaharakov (1973). Data from the UFG alloy indicates marginally higher permeability (< 10×) at lower temperatures, but the permeability converges to that of the ITER tungsten at 1000 °C. The permeation cell uses only ceramic and graphite materials in the hot zone to reduce the possibility for oxidation of the sample membrane. Sealing pressure is applied externally, thereby allowing for elevation

  16. Efficacy of Tantalum Tungsten Alloys for Diffusion Barrier Applications

    Science.gov (United States)

    Smathers, D. B.; Aimone, P. R.

    2017-12-01

    Traditionally either Niobium, Tantalum or a combination of both have been used as diffusion barriers in Nb3Sn Multi-filament wire. Vanadium has also been used successfully but the ultimate RRR of the copper is limited unless an external shell of Niobium is included. Niobium is preferred over Tantalum when alternating current losses are not an issue as the Niobium will react to form Nb3Sn. Pure Tantalum tends to deform irregularly requiring extra starting thickness to ensure good barrier qualities. Our evaluations showed Tantalum lightly alloyed with 3 wt% Tungsten is compatible with the wire drawing process while deforming as well as or better than pure Niobium. Ta3wt%W has been processed as a single barrier and as a distributed barrier to fine dimensions. In addition, the higher modulus and strength of the Tantalum Tungsten alloy improves the overall tensile properties of the wire.

  17. Flow behaviour of a heat treated tungsten heavy alloy

    International Nuclear Information System (INIS)

    Das, Jiten; Sarkar, R.; Rao, G. Appa; Sankaranarayana, M.; Nandy, T.K.; Pabi, S.K.

    2012-01-01

    Highlights: ► An Arrhenius type of constitutive equation is proposed for the investigated alloy. ► Peierl's controlled dislocation motion is observed at low temperature. ► Transition from Peierl's to forest controlled mechanism is observed at 673 K. ► At room temperature predominantly tungsten grain, cleavage fracture is observed. ► At elevated temperature predominantly intergranular fracture is observed. - Abstract: Flow behaviour of a tungsten heavy alloy was studied in the strain rate-temperature range of 10 −5 –1/s and 298–973 K, respectively. It was observed in this study that the dislocation motion in tungsten heavy alloy was controlled by a Peierl's mechanism at low temperatures (up to 573 K). This was confirmed by the magnitude of apparent activation volume and apparent activation enthalpy as well as TEM observations. Apparent activation enthalpy in the Peierls regime, determined by several methods, was found to vary in between 22 and 37 kJ/mol. An Arrhenius type of constitutive equation was also proposed in the Peierls controlled regime for predicting flow stress as a function of temperature and strain rate. Transition temperature of rate controlling mechanism—from Peierl's mechanism to forest mechanism—was determined from the strain rate sensitivity and apparent activation volume estimation at several temperatures. The transition temperature was found to be about 673 K.

  18. Dendrite tungsten liquation in molybdenum alloys

    International Nuclear Information System (INIS)

    Kantor, M.M.; Ageeva, E.N.; Kolotinskij, V.N.

    1992-01-01

    A study was made on primary crystallization structure of ingots of Mo-W-B system alloys with electron microscopy were used to establish, that cells and cellular dendrites were the main elements of primary crystallization structure. Method of local X-ray spectral analysis enabled to establish, that intracrystallite liquation at cellular growth developed more intensively, as compared to the case of cellular dendrite formation. Change of boron content in alloys didn't practically affect the degree of development of intracrystallite W liquation in Mo

  19. Electrokinetic treatment of firing ranges containing tungsten-contaminated soils

    International Nuclear Information System (INIS)

    Braida, Washington; Christodoulatos, Christos; Ogundipe, Adebayo; Dermatas, Dimitris; O'Connor, Gregory

    2007-01-01

    Tungsten-based alloys and composites are being used and new formulations are being considered for use in the manufacturing of different types of ammunition. The use of tungsten heavy alloys (WHA) in new munitions systems and tungsten composites in small caliber ammunition could potentially release substantial amounts of this element into the environment. Although tungsten is widely used in industrial and military applications, tungsten's potential environmental and health impacts have not been thoroughly addressed. This necessitates the research and development of remedial technologies to contain and/or remove tungsten from soils that may serve as a source for water contamination. The current work investigates the feasibility of using electrokinetics for the remediation of tungsten-contaminated soils in the presence of other heavy metals of concern such as Cu and Pb with aim to removing W from the soil while stabilizing in situ, Pb and Cu

  20. Heavy Metals and Radioactive Characterization of the Main Materials Involved in the HC-FeMn Alloy Production Process

    Energy Technology Data Exchange (ETDEWEB)

    Badran, H. [Taif University (Saudi Arabia); Bakr, H.; Elnimr, T. [Tanta University (Egypt); Sharshar, T. [Kafrelsheikh University (Egypt)

    2014-07-01

    Natural occurring radioactive materials (NORM) are always present in association with a variety of elements in the geological formations. The extraction of non-radioactive minerals from the mineral matrices may lead to the buildup of NORM in wastes and/or end product with different concentrations of uranium and thorium daughters, depending on extraction procedures, initial concentrations and chemical forms of the NORM in the mineral matrices. Gamma-ray spectrometry was used for the quantitative assessment of radionuclides and the associated radiation hazards at the high carbon Ferromanganese alloy (HC-FeMn) production plant in Abu Zenima (West Sinai, Egypt). The low grad Mn from Um Bogma is mixed with Norwegian Mn to improve its quality. While the Egyptian raw Mn is richer in {sup 238}U, Cu and Zn, the Norwegian raw Mn is richer in {sup 40}K and Mn. The mixing process leads to increasing concentrations of {sup 226}Ra and Zn. Enhanced concentrations of Mn, Cu and Zn were also found in the waste. The radioactivity concentrations of {sup 226}Ra, {sup 232}Th and {sup 40}K in different raw materials used in the alloy formation process, HC-FeMn alloy, waste and other mining products produced by the same company are also determined. The estimated range of the total activities of wastes produced annually by the extraction process are 8.7-17.3, 0.7-1.3 and 6.7-13.4 GBq for {sup 226}Ra, {sup 232}Th and {sup 40}K, respectively. The calculated absorbed dose rate and the annual effective dose equivalent in waste dumps with these increased fractions of NORM are 225 nGy/h and 276 mSv, respectively. This investigation does not recommend the use of the waste in housing construction or as filling materials in the area where houses may be built on or near the tailing piles. Document available in abstract form only. (authors)

  1. Bioaccumulation of Heavy Metals

    African Journals Online (AJOL)

    komla

    acute toxicity and sublethal chronic action the devastating effects that the accumulation - including ... the laboratory and kept in holding glass (a) Copper as CuSO,.5H,0 ... from 2 psu to 21 psu) depending on time of The choice of heavy metals for this s year. ... serving as substrate and food source for Salinity of test media.

  2. Evaluation of the feasibility of joining titanium alloy to heavymet tungsten alloy

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-07

    Information is presented on a program to select and evaluate methods of brazing and/or explosively welding Ti-6Al-4V titanium alloy to Heavymet, a tungsten-base metal containing up to about 20% alloying elements (nickel, copper, etc.) to improve its ductility and other mechanical properties. Designs permitting the reliable production of joints between these base metals were of interest too. While this investigation was primarily concerned with an engineering study of the problems associated with joining these base metals in the required configuration, limited experimental studies were conducted also. The joining methods are reviewed individually. Recommendations for developing a viable titanium-tungsten joining procedure are discussed.

  3. Evaluation of the feasibility of joining titanium alloy to heavymet tungsten alloy

    International Nuclear Information System (INIS)

    1978-01-01

    Information is presented on a program to select and evaluate methods of brazing and/or explosively welding Ti-6Al-4V titanium alloy to Heavymet, a tungsten-base metal containing up to about 20% alloying elements (nickel, copper, etc.) to improve its ductility and other mechanical properties. Designs permitting the reliable production of joints between these base metals were of interest too. While this investigation was primarily concerned with an engineering study of the problems associated with joining these base metals in the required configuration, limited experimental studies were conducted also. The joining methods are reviewed individually. Recommendations for developing a viable titanium-tungsten joining procedure are discussed

  4. (17) ACCUMULATION OF HEAVY METAL

    African Journals Online (AJOL)

    Adeyinka Odunsi

    Spectrophotometer (AAS) 2ID using their respective lamp and wavelengths. Calculation ... (Table 2). Concentration of heavy metals in the cassava. Lead and chromium were not significantly ..... Market basket survey for some heavy metals in ...

  5. Solid-state sintering of tungsten heavy alloys

    International Nuclear Information System (INIS)

    Gurwell, W.E.

    1994-10-01

    Solid-state sintering is a technologically important step in the fabrication of tungsten heavy alloys. This work addresses practical variables affecting the sinterability: powder particle size, powder mixing, and sintering temperature and time. Compositions containing 1 to 10 micrometer (μM) tungsten (W) powders can be fully densified at temperatures near the matrix solidus. Blending with an intensifier bar provided good dispersion of elemental powders and good as-sintered mechanical properties under adequate sintering conditions. Additional ball milling increases powder bulk density which primarily benefits mold and die filling. Although fine, 1 μm W powder blends have high sinterability, higher as-sintered ductilities are reached in shorter sintering times with coarser, 5 μm W powder blends; 10μm W powder blends promise the highest as-sintered ductilities due to their coarse microstructural W

  6. Property change of advanced tungsten alloys due to neutron irradiation

    International Nuclear Information System (INIS)

    Fukuda, Makoto; Hasegawa, Akira; Tanno, Takashi; Nogami, Shuhei; Kurishita, Hiroaki

    2013-01-01

    This study investigates the effect of neutron irradiation on the functional properties of pure tungsten (W) and advanced tungsten alloys (e.g., lanthanum (La)-doped W, potassium (K)-doped W, and ultra-fine-grained (UFG) W–TiC alloys) tested in the Japan Materials Testing Reactor (JMTR) or experimental fast reactor Joyo. The irradiation temperature and damage were in the range 804–1073 K and 0.15–0.47 dpa, respectively. TEM images of all samples after 0.42 dpa irradiation at 1023 K showed voids, black dots, and dislocation loops, indicating that similar damage structures were formed in pure W, La-doped W, K-doped W, and UFG W–0.5 wt% TiC. The electrical resistivity of all specimens increased following neutron irradiation. Nearly identical electrical resistivity and irradiation hardening were observed in pure W, La-doped W, and K-doped W. The electrical resistivity of UFG W–TiC was higher than that of other specimens before and after irradiation, which may be attributed to its ultra-fine-grain structure, as well as the presence of impurities introduced during the alloying process. Compared to the other specimens, the UFG W–TiC was more resistant to irradiation hardening

  7. Freeze-dried processing of tungsten heavy alloys

    International Nuclear Information System (INIS)

    White, G.D.; Gurwell, W.E.

    1989-06-01

    Tungsten heavy alloy powders were produced from freeze-dried aqueous solutions of ammonium metatungstate and, principally, sulfates of Ni and Fe. The freeze-dried salts were calcined and hydrogen reduced to form very fine, homogeneous, low-density, W heavy alloy powders having a coral-like structure with elements of approximately 0.1 μm in diameter. The powders yield high green strength and sinterability. Tungsten heavy alloy powders of 70%, 90%, and 96% W were prepared by freeze drying, compacted, and solid-state (SS) sintered to fully density at temperatures as low as 1200 degree C and also at conventional liquid-phase (LP) sintering temperatures. Solid-state sintered microstructures contained polygonal W grains with high contiguity; the matrix did not coat and separate the W grains to form low-contiguity, high-ductility structures. Liquid-phase sintered microstructures were very conventional in appearance, having W spheroids of low contiguity. All these materials were found to be brittle. High levels of residual S accompanied by segregation of the S to all the microstructural interfaces are principally responsible for the brittleness; problems with S could be eliminated by using Fe and Ni nitrates rather than the sulfates. 9 refs., 22 figs., 3 tabs

  8. Durability of adhesive bonds to uranium alloys, tungsten, tantalum, and thorium

    International Nuclear Information System (INIS)

    Childress, F.G.

    1975-01-01

    Long-term durability of epoxy bonds to alloys of uranium (U-Nb and Mulberry), nickel-plated uranium, thorium, tungsten, tantalum, tantalum--10 percent tungsten, and aluminum was evaluated. Significant strengths remain after ten years of aging; however, there is some evidence of bond deterioration with uranium alloys and thorium stored in ambient laboratory air

  9. Heavy metals in our foodstuffs

    Energy Technology Data Exchange (ETDEWEB)

    1983-11-01

    The special group ''chemistry of food and forensic chemistry'' of the Association of German Analytical Chemists in Munich in 1983 issued a statement on that subject. The publication points out how heavy metals (examples: lead, cadmium and mercury) make their way into the foodstuffs, how many heavy metals are contained in our foodstuffs, which heavy metals are indispensable minerals and which aren't, and which heavy metals are ingested with food. It concludes by discussing how heavy metal contamination of our food can be prevented.

  10. The effect of tungsten on mechanical properties of the Ti-9% Al-3% Zr alloy

    International Nuclear Information System (INIS)

    Nartova, T.T.; Grigor'ev, I.P.; Stepanov, Yu.N.; Tarasova, O.B.

    1979-01-01

    The effect of tungsten (from 0 to 10 %) on mechanical properties of the ternary Ti-9 %, Al-3 % Zr alloy, has been studied. The microstructure, tensile properties at 20 and 600 deg C and Vickers hardness in as-forged and as-annealed states have been studied. The experiments have shown that the ultimate strength increases with tungsten content. Titanium alloys with 9 % Al and 3 % Zr in the case of varying tungsten content at 20 deg C fracture by brittle mechanism. The dUctility of the annealed alloy does not rise at 20 deg C, but at the test temperature of 600 deg C the alloy becomes ductile

  11. Effect of two-stage sintering process on microstructure and mechanical properties of ODS tungsten heavy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyong H. [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701 (Korea, Republic of); Cha, Seung I. [International Center for Young Scientists, National Institute for Materials Science 1-1, Namiki, Tsukuba 305-0044 (Japan); Ryu, Ho J. [DUPIC, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yusong-gu, Taejon 305-353 (Korea, Republic of); Hong, Soon H. [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701 (Korea, Republic of)], E-mail: shhong@kaist.ac.kr

    2007-06-15

    Oxide dispersion strengthened (ODS) tungsten heavy alloys have been considered as promising candidates for advanced kinetic energy penetrator due to their characteristic fracture mode compared to conventional tungsten heavy alloy. In order to obtain high relative density, the ODS tungsten heavy alloy needs to be sintered at higher temperature for longer time, however, induces growth of tungsten grains. Therefore, it is very difficult to obtain controlled microstructure of ODS tungsten heavy alloy having fine tungsten grains with full densification. In this study, two-stage sintering process, consisted of primary solid-state sintering and followed by secondary liquid phase sintering, was introduced for ODS tungsten heavy alloys. The mechanically alloyed 94W-4.56Ni-1.14Fe-0.3Y{sub 2}O{sub 3} powders are solid-state sintered at 1300-1450 deg. C for 1 h in hydrogen atmosphere, and followed by liquid phase sintering temperature at 1465-1485 deg. C for 0-60 min. The microstructure of ODS tungsten heavy alloys showed high relative density above 97%, with contiguous tungsten grains after primary solid-state sintering. The microstructure of solid-state sintered ODS tungsten heavy alloy was changed into spherical tungsten grains embedded in W-Ni-Fe matrix during secondary liquid phase sintering. The two-stage sintered ODS tungsten heavy alloy from mechanically alloyed powders showed finer microstructure and higher mechanical properties than conventional liquid phase sintered alloy. The mechanical properties of ODS tungsten heavy alloys are dependent on the microstructural parameters such as tungsten grain size, matrix volume fraction and tungsten/tungsten contiguity, which can be controlled through the two-stage sintering process.

  12. Comparison of four tungsten alloys for use as ultrasonic thermometer sensors

    International Nuclear Information System (INIS)

    Arave, A.E.

    1975-06-01

    Four tungsten alloy materials were evaluated for use as ultrasonic sensors: (a) tungsten, (b) tungsten-1 percent thoria, (c) tungsten-2 percent thoria, and (d) tungsten-26 percent rhenium. Four parameters were checked: (1) temperature sensitivity, (2) signal attenuation as a function of temperature, (3) temperature sensitivity as a function of frequency, and (4) relative signal attenuation as a function of frequency. The temperature sensors were designed for the Loss-of-Fluid Test (LOFT) and Power Burst Facility (PBF) reactors. (U.S.)

  13. Pulse current electrodeposition of tungsten coatings on V–4Cr–4Ti alloy

    International Nuclear Information System (INIS)

    Jiang, Fan; Zhang, Yingchun; Li, Xuliang

    2015-01-01

    Highlights: • Tungsten coatings were successfully electroplated on vanadium alloy substrate. • Tungsten coatings consisted of two sub-layers. • Tungsten coatings plated at lower duty cycle has a better surface quality. • High heat flux property of tungsten coatings was investigated. • Helium ion irradiation property of tungsten coatings was investigated. - Abstract: Tungsten coatings with high (2 2 0)-orientation were formed on V alloy substrate by pulse current electrodeposition in air atmosphere. The coatings’ microstructure, crystal structure and adhesive strength between coatings and substrates were investigated. It could be observed the tungsten coatings consisted of two sub-layers with the inner tooth-like layer, and the outer columnar layer. The tungsten coatings deposited at lower duty cycle have a better surface quality with a little change in the adhesive strength. The tungsten coating was exposed to electron beam with power density of 200 MW/m 2 in the thermal shock test, the tungsten crystal grain surface melt, the microcracks are found among the crystal grains. Exfoliation, flaking and dense needle-like holes were observed on the tungsten coating after irradiation with helium ions at an energy of 65 keV and an implanted dose of 22.67 × 10 18 cm −2

  14. Morphological characterisation and spectroscopic studies of the corrosion behaviour of tungsten heavy alloys

    International Nuclear Information System (INIS)

    Ogundipe, A.; Greenberg, B.; Braida, W.; Christodoulatos, C.; Dermatas, D.

    2006-01-01

    Tungsten-based alloys have been used in a wide variety of industrial and military applications. These alloys are composed mainly of tungsten (88-95%) with various combinations of nickel, cobalt, iron and copper usually making up the remaining fraction. The corrosion behaviours of five munitions grade tungsten alloys of interest have been examined using immersion tests and wet-dry cycle tests to determine the mechanisms involved in the release of the metallic components. Analyses carried out using SEM, EDS and grazing incidence XRD techniques, show the release of tungsten as well as alloying elements due to galvanic corrosion resulting from the difference in electrode potential between the tungsten phase and the binder phase in all cases studied. The extent of corrosion was directly related with the dissolution of tungsten in the binder phase during the sintering stage of manufacture. In W-Ni-Co-Fe alloys binder phase corrosion was observed while the relatively noble tungsten phase was less affected. The reverse was observed for a W-Cu alloy

  15. Smart tungsten alloys as a material for the first wall of a future fusion power plant

    Science.gov (United States)

    Litnovsky, A.; Wegener, T.; Klein, F.; Linsmeier, Ch.; Rasinski, M.; Kreter, A.; Unterberg, B.; Coenen, J. W.; Du, H.; Mayer, J.; Garcia-Rosales, C.; Calvo, A.; Ordas, N.

    2017-06-01

    Tungsten is currently deemed as a promising plasma-facing material (PFM) for the future power plant DEMO. In the case of an accident, air can get into contact with PFMs during the air ingress. The temperature of PFMs can rise up to 1200 °C due to nuclear decay heat in the case of damaged coolant supply. Heated neutron-activated tungsten forms a volatile radioactive oxide which can be mobilized into the atmosphere. New self-passivating ‘smart’ alloys can adjust their properties to the environment. During plasma operation the preferential sputtering of lighter alloying elements will leave an almost pure tungsten surface facing the plasma. During an accident the alloying elements in the bulk are forming oxides thus protecting tungsten from mobilization. Good plasma performance and the suppression of oxidation are required for smart alloys. Bulk tungsten (W)-chroimum (Cr)-titanium (Ti) alloys were exposed together with pure tungsten (W) samples to the steady-state deuterium plasma under identical conditions in the linear plasma device PSI 2. The temperature of the samples was ~576 °C-715 °C, the energy of impinging ions was 210 eV matching well the conditions expected at the first wall of DEMO. Weight loss measurements demonstrated similar mass decrease of smart alloys and pure tungsten samples. The oxidation of exposed samples has proven no effect of plasma exposure on the oxidation resistance. The W-Cr-Ti alloy demonstrated advantageous 3-fold lower mass gain due to oxidation than that of pure tungsten. New yttrium (Y)-containing thin film systems are demonstrating superior performance in comparison to that of W-Cr-Ti systems and of pure W. The oxidation rate constant of W-Cr-Y thin film is 105 times less than that of pure tungsten. However, the detected reactivity of the bulk smart alloy in humid atmosphere is calling for a further improvement.

  16. Tungsten determination in heat resistant nickel-base-alloys by the method of atomic absorption

    International Nuclear Information System (INIS)

    Gregorczyk, S.; Wycislik, A.

    1980-01-01

    A method of atomic absorption was developed. It allows for the tungsten to be determined in heatresistant nickel-base-alloys within the range 0.01 to 7%. It consists in precipitating tungsten acid in the presence of alkaloids with its following decomposition by hydrofluoric acid in the teflon bomb. (author)

  17. Heavy metals and soil microbes

    NARCIS (Netherlands)

    Giller, K.E.; Witter, E.; McGrath, S.

    2009-01-01

    The discovery in the early 1980s that soil microorganisms, and in particular the symbiotic bacteria Rhizobium, were highly sensitive to heavy metals initiated a new line of research. This has given us important insights into a range of topics: ecotoxicology, bioavailability of heavy metals, the role

  18. Determination of tungsten in high-alloy steels and heat resisting alloys by isotope dilution-spark source mass spectrometry

    International Nuclear Information System (INIS)

    Saito, Morimasa; Yamada, Kei; Okochi, Haruno; Hirose, Fumio

    1983-01-01

    Tungsten in high-alloy steels and heat-resisting alloys was determined by isotope dilution method combined with spark source mass spectrometry by using 183 W enriched tungsten. The spike solution was prepared by fusing tungsten trioxide in sodium carbonate. A high-alloy steel sample was dissolved in the mixture of sulfuric acid and phosphoric acid together with the spike solution; a sample of heat resisting alloy was similarly dissolved in the mixture of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid. The solution was evaporated to give dense white fumes. Tungsten was separated from the residue by a conventional cinchonine salt-precipitation method. The salt was ignited, and the residue was mixed with graphite powder and pressed into electrodes. The isotope 183 W and 184 W were measured. The method was applied to the determination of tungsten in JSS and NBS standard high-alloy steels and JAERI standard nickel- and NBS standard cobalt-base heat resisting alloys containing more than 0.05% tungsten. The results were obtained with satisfactory precision and accuracy. However, the results obtained for JSS standard high- speed steels containing molybdenum tended to be significantly lower than the certified values. (author)

  19. Heavy metal sorption by microalgae

    International Nuclear Information System (INIS)

    Sandau, E.; Sandau, P.; Pulz, O.

    1996-01-01

    Viable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small-scale cultivation tests (50 l) with Cd-resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died. Non-viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by-products changes only insignificantly. Their low price makes them economical. (orig.)

  20. Irradiation induced precipitation in tungsten based, W-Re alloys

    Science.gov (United States)

    Williams, R. K.; Wiffen, F. W.; Bentley, J.; Stiegler, J. O.

    1983-03-01

    Tungsten-base alloys containing 5, 11, and 25 pct Re were irradiated in the EBR-II reactor. Irradiation temperatures ranged from 600 to 1500 °C. All compositions were irradiated to fluences in the range 4.3 to 6.1 X 1025 n/m2 (E > 0.1 MeV), and three 25 pct Re samples were also irradiated to 3.7 X 1026 n/m2 at temperatures 700 to 900 °C. Postirradiation examination included measurement of electrical resistivity at room temperature and lower temperatures, X-ray diffraction, optical metallography, microprobe analysis, and transmission electron microscopy. Irradiation induced resistivity decreases observed in most of the samples suggested second-phase precipitation. Complete results confirmed the precipitate formation in all samples, in disagreement with existing phase diagrams for the W-Re system. Electron diffraction showed the precipitates to be consistent with the cubic, Re-rich X-phase and inconsistent with the σ-phase. Large variations in precipitate morphology and distribution were observed between the different compositions and irradiation conditions. For the 5 and 11 pct Re-alloys, spherically symmetric strain fields surrounded the equiaxed precipitate particles, and were observed even where no particles were visible. These strain fields are believed to arise from local Re enrichment. Thermoelectric data show that the precipitation can lead to decalibration of W/Re thermocouples.

  1. Matrix composition effects on the tensile properties of tungsten-molybdenum heavy alloys

    International Nuclear Information System (INIS)

    Bose, A.; German, R.N.

    1990-01-01

    Tungsten-base heavy alloys are liquid-phase sintered from mixed tungsten, nickel, and iron powders. The sintered product is a composite consisting of interlaced tungsten and solidified matrix (W-Ni-Fe) phases. These alloys are most useful in applications requiring high density, strength, and toughness. The design of improved tungsten heavy alloys has been the subject of several research investigations. Much success has taken place through improved processing, but parallel compositional studies have resulted in new microstructure-property combinations. As part of these investigations, the Ni/Fe ratio has been varied, with the general conclusion that optimal strength and ductility occur with a ratio between 2 and 4. Brittle intermetallic phases can form outside of this composition range. Historically, a 7/3 Ni/Fe ratio has been selected for processing studies. Recently, others reported higher ductilities and impact energies for 90 and 93 pct W heavy alloys with the 8/2 Ni/Fe ratio. Alternatively, these alloys can be strengthened by both solid solution and grain size refinement through incorporation of molybdenum, tantalum, or rhenium. These additions are soluble in both the tungsten and matrix phases and retard solution-reprecipitation during liquid phase sintering. In this study, the alloy composition was varied in the nickel/iron ratio and molybdenum was partially substituted for tungsten. The sintered tensile properties are assessed vs these compositional variations

  2. Toxicity of heavy metals in the environment

    National Research Council Canada - National Science Library

    Oehme, F.W

    1978-01-01

    ... as the fundamental mechanisms of toxicity resulting from heavy metal chemicals. The more common toxic heavy metals, along with their biochemistry and associated clinical syndromes, are then described...

  3. Effect of composition on the high rate dynamic behaviour of tungsten heavy alloys

    Directory of Open Access Journals (Sweden)

    Latif Kesemen

    2015-01-01

    Full Text Available Tungsten heavy alloys are currently used as kinetic energy penetrators in military applications due to their high density and superior mechanical properties. In the literature, quasi-static properties of different tungsten heavy alloys based on W-Ni-Cu and W-Ni-Fe ternary systems are well documented and presented. However, comparison of the dynamic behaviour of these alloys in terms of the correlation between quasi-static mechanical characterization and dynamical properties is lacking. In the present study, dynamic properties of tungsten heavy alloys having different binder phase compositions (90W-7Ni-3Cu and 90W-8Ni-2Fe at different projectile velocities were investigated. The examined and tested alloys were produced through the conventional powder metallurgy route of mixing, cold compaction and sintering. Mechanical characterization of these alloys was performed. In the ballistic tests, cylindrical tungsten heavy alloys with L/D ratio of 3 were impacted to hardened steel target at different projectile velocities. After the ballistic tests, deformation characteristics of test specimens during dynamic loading were evaluated by comparing the change of length and diameter of the specimens versus kinetic energy densities. The study concluded that 90W-8Ni-2Fe alloy has better perforation characteristics than 90W-7Ni-3Cu alloy.

  4. Bonding tungsten, W–Cu-alloy and copper with amorphous Fe–W alloy transition

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song, E-mail: wangsongrain@163.com [Laboratory of Special Ceramics and Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Ling, Yunhan, E-mail: yhling@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Zhao, Pei [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Zang, Nanzhi [Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Wang, Jianjun [Laboratory of Special Ceramics and Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Guo, Shibin [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Jun [Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Xu, Guiying [Laboratory of Special Ceramics and Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China)

    2013-05-15

    W/Cu graded materials are the leading candidate materials used as the plasma facing components in a fusion reactor. However, tungsten and copper can hardly be jointed together due to their great differences in physical properties such as coefficient of thermal expansion and melting point, and the lack of solid solubility between them. To overcome those difficulties, a new amorphous Fe–W alloy transitional coating and vacuum hot pressing (VHP) method were proposed and introduced in this paper. The morphology, composition and structure of the amorphous Fe–W alloy coating and the sintering interface of the specimens were analyzed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The thermal shock resistance of the bonded composite was also tested. The results demonstrated that amorphous structure underwent change from amorphous to nano grains during joining process, and the joined W/Cu composite can endued plasma thermal shock resistance with energy density more than 5.33 MW/m{sup 2}. It provides a new feasible technical to join refractory tungsten to immiscible copper with amorphous Fe–W alloy coating.

  5. Synthesis of high purity tungsten nanoparticles from tungsten heavy alloy scrap by selective precipitation and reduction route

    International Nuclear Information System (INIS)

    Kamal, S.S. Kalyan; Sahoo, P.K.; Vimala, J.; Shanker, B.; Ghosal, P.; Durai, L.

    2016-01-01

    In this paper we report synthesis of tungsten nanoparticles of high purity >99.7 wt% from heavy alloy scrap using a novel chemical route of selective precipitation and reduction. The effect of Poly(vinylpyrrolidone) polymer on controlling the particle size is established through FTIR spectra and corroborated with TEM images, wherein the average size decreased form 210 to 45 nm with increasing PVP content from zero to 2 g under different experimental conditions. This process is economical as raw material is a scrap and the efficiency of the reaction is >95%. - Highlights: • Tungsten nanoparticles were synthesized from tungsten heavy alloy scrap. • A novel chemical route of precipitation and reduction with Poly(vinylpyrrolidone) polymer as stabilizer is reported. • The average size decreased form 210 to 45 nm with increasing PVP content from zero to 2 g. • High pure tungsten nanoparticles of >99.7% purity could be synthesized using this route. • Efficiency of the reaction is >95%.

  6. Magnetization curves of sintered heavy tungsten alloys for applications in MRI-guided radiotherapy

    International Nuclear Information System (INIS)

    Kolling, Stefan; Oborn, Bradley M.; Keall, Paul J.; Horvat, Joseph

    2014-01-01

    Purpose: Due to the current interest in MRI-guided radiotherapy, the magnetic properties of the materials commonly used in radiotherapy are becoming increasingly important. In this paper, measurement results for the magnetization (BH) curves of a range of sintered heavy tungsten alloys used in radiation shielding and collimation are presented. Methods: Sintered heavy tungsten alloys typically contain >90 % tungsten and 0 and the BH curve derived. Results: The iron content of the alloys was found to play a dominant role, directly influencing the magnetizationM and thus the nonlinearity of the BH curve. Generally, the saturation magnetization increased with increasing iron content of the alloy. Furthermore, no measurable magnetization was found for all alloys without iron content, despite containing up to 6% of nickel. For two samples from different manufacturers but with identical quoted nominal elemental composition (95% W, 3.5% Ni, 1.5% Fe), a relative difference in the magnetization of 11%–16% was measured. Conclusions: The measured curves show that the magnetic properties of sintered heavy tungsten alloys strongly depend on the iron content, whereas the addition of nickel in the absence of iron led to no measurable effect. Since a difference in the BH curves for two samples with identical quoted nominal composition from different manufacturers was observed, measuring of the BH curve for each individual batch of heavy tungsten alloys is advisable whenever accurate knowledge of the magnetic properties is crucial. The obtained BH curves can be used in FEM simulations to predict the magnetic impact of sintered heavy tungsten alloys

  7. Tungsten

    International Nuclear Information System (INIS)

    Eschnauer, H.

    1978-01-01

    There is no substitute for tungsten in its main field of application so that the demand will not decrease, but there is a need for further important applications. If small variations are left out of account, a small but steady increase in the annual tungsten consumption can be expected. The amount of tungsten available will increase due to the exploritation of new deposits and the extension of existing mines. This tendency will probably be increased by the world-wide prospection. It is hard to make an assessment of the amount of tungsten are obtained in the People's Republic of china, the purchases of Eastern countries in the West, and the sales policy of the USA; pice forecasts are therefore hard to make. A rather interesting subject with regard to the tungsten cycle as a whole is the reprocessing of tungsten-containing wastes. (orig.) [de

  8. Oxidation behaviour of silicon-free tungsten alloys for use as the first wall material

    Science.gov (United States)

    Koch, F.; Brinkmann, J.; Lindig, S.; Mishra, T. P.; Linsmeier, Ch

    2011-12-01

    The use of self-passivating tungsten alloys as armour material of the first wall of a fusion power reactor may be advantageous concerning safety issues. In earlier studies good performance of the system W-Cr-Si was demonstrated. Thin films of such alloys showed a strongly reduced oxidation rate compared to pure tungsten. However, the formation of brittle tungsten silicides may be disadvantageous for the powder metallurgical production of bulk W-Cr-Si alloys if a good workability is needed. This paper shows the results of screening tests to identify suitable silicon-free alloys with distinguished self-passivation and a potentially good workability. Of all the tested systems W-Cr-Ti alloys showed the most promising results. The oxidation rate was even lower than the one of W-Cr-Si alloys, the reduction factor was about four orders of magnitude compared to pure tungsten. This performance could be conserved even if the content of alloying elements was reduced.

  9. Oxidation behaviour of silicon-free tungsten alloys for use as the first wall material

    International Nuclear Information System (INIS)

    Koch, F; Brinkmann, J; Lindig, S; Mishra, T P; Linsmeier, Ch

    2011-01-01

    The use of self-passivating tungsten alloys as armour material of the first wall of a fusion power reactor may be advantageous concerning safety issues. In earlier studies good performance of the system W-Cr-Si was demonstrated. Thin films of such alloys showed a strongly reduced oxidation rate compared to pure tungsten. However, the formation of brittle tungsten silicides may be disadvantageous for the powder metallurgical production of bulk W-Cr-Si alloys if a good workability is needed. This paper shows the results of screening tests to identify suitable silicon-free alloys with distinguished self-passivation and a potentially good workability. Of all the tested systems W-Cr-Ti alloys showed the most promising results. The oxidation rate was even lower than the one of W-Cr-Si alloys, the reduction factor was about four orders of magnitude compared to pure tungsten. This performance could be conserved even if the content of alloying elements was reduced.

  10. Tissue distribution patterns of solubilized metals from internalized tungsten alloy in the F344 rat

    Directory of Open Access Journals (Sweden)

    Vernieda B. Vergara

    2016-06-01

    Full Text Available Because of its unique physical and chemical properties, tungsten has been increasingly utilized in a variety of civilian and military applications. This expanded use also raises the risk of human exposure through internalization by various routes. In most cases the toxicological and carcinogenic properties of these tungsten-based compounds are not known nor are the dissolution biokinetics and ultimate fate of the associated metals. Using a laboratory rodent model system designed to assess the health effects of embedded metals, and a tungsten alloy comprised of tungsten (91.1%, nickel (6.0%, and cobalt (2.9%, we investigated the tissue distribution patterns of the metals over a six month period. Despite its perceived insolubility, tungsten rapidly solubilized from the implanted metal fragments, as did nickel and cobalt. All three metals distributed systemically over time with extremely elevated levels of all three metals found in kidney, liver, and spleen. Unexpectedly, tungsten was found to cross the blood-brain and blood-testis barriers and localize in those tissues. These results, along with recent reports suggesting that tungsten is a tumor promoter, raises serious concerns as to the long-term health effects of exposure to tungsten and tungsten-based compounds.

  11. Recent progress in R and D on tungsten alloys for divertor structural and plasma facing materials

    Energy Technology Data Exchange (ETDEWEB)

    Wurster, S., E-mail: stefan.wurster@oeaw.ac.at [Erich Schmid Institute of Materials Science, Austria and Association EURATOM-ÖAW, Jahnstrasse 12, A-8700 Leoben (Austria); Baluc, N.; Battabyal, M. [Ecole Polytechnique Fédérale de Lausanne (EPFL), Villigen PSI (Switzerland); Crosby, T. [University of California, Mechanical and Aerospace Engineering Department, Los Angeles, CA (United States); Du, J. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); García-Rosales, C. [Centro de Estudios e Investigaciones Técnicas de Gipuzkoa (CEIT), San Sebastián (Spain); Hasegawa, A. [Department of Quantum Science and Energy Engineering, Faculty of Engineering, Tohoku University (Japan); Hoffmann, A. [Plansee Metall GmbH, Reutte (Austria); Kimura, A. [Institute of Advanced Energy, Kyoto University (Japan); Kurishita, H. [International Research Center for Nuclear Material Science, Institute for Materials Research, Tohoku University (Japan); Kurtz, R.J. [Pacific Northwest National Laboratory, Richland, WA (United States); Li, H. [Erich Schmid Institute of Materials Science, Austria and Association EURATOM-ÖAW, Jahnstrasse 12, A-8700 Leoben (Austria); Chair of Atomistic Modelling and Design of Materials, University of Leoben, Leoben (Austria); Noh, S.; Reiser, J. [Karlsruhe Institute of Technology, Karlsruhe (Germany); Riesch, J. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Rieth, M. [Karlsruhe Institute of Technology, Karlsruhe (Germany); Setyawan, W. [Pacific Northwest National Laboratory, Richland, WA (United States); Walter, M. [Karlsruhe Institute of Technology, Karlsruhe (Germany); You, J.-H. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); and others

    2013-11-15

    Tungsten materials are candidates for plasma-facing components for the International Thermonuclear Experimental Reactor and the DEMOnstration power plant because of their superior thermophysical properties. Because these materials are not common structural materials like steels, knowledge and strategies to improve the properties are still under development. These strategies discussed here, include new alloying approaches and microstructural stabilization by oxide dispersion strengthened as well as TiC stabilized tungsten based materials. The fracture behavior is improved by using tungsten laminated and tungsten wire reinforced materials. Material development is accompanied by neutron irradiation campaigns. Self-passivation, which is essential in case of loss-of-coolant accidents for plasma facing materials, can be achieved by certain amounts of chromium and titanium. Furthermore, modeling and computer simulation on the influence of alloying elements and heat loading and helium bombardment will be presented.

  12. Development of a tungsten heavy alloy, W-Ni-Mn, used as kinetic energy penetrator

    International Nuclear Information System (INIS)

    Zahraee, S. M.; Salehi, M. T.; Arabi, H.; Tamizifar, M.

    2007-01-01

    The objective of this research was to develop a tungsten heavy alloy having a microstructure and properties good enough to penetrate hard rolled steels as deep as possible. In addition this alloy should not have environmental problems as depleted uranium materials, For this purpose a wide spread literature survey was performed and on the base of information obtained in this survey, three compositions of tungsten heavy alloy were chosen for investigation in this research. The alloys namely 90 W-7 Ni-3 Fe, 90 W-9 Ni-Mn and 90 W-8 Ni-2 Mn were selected and after producing these alloys through powder metallurgy technique, their thermal conductivity, compression flow properties and microstructure, were studied. The results of these investigations indicated that W-Ni-Mn alloys had better flow properties and lower thermal conductivities relative to W-Ni-Fe alloy. In addition Mn helped to obtain a finer microstructure in tungsten heavy alloy. Worth mentioning that a finer microstructure as well as lower thermal conductivity in this type of alloys increased the penetration depth due to formation of adiabatic shear bands during impact

  13. Study of neutron induced outgassing from tungsten alloy for ATLAS FCAL

    CERN Document Server

    Leroy, C; Cheplakov, A P; Golikov, V; Golubyh, S M; Kulagin, E; Kukhtin, V; Luschikov, V

    1999-01-01

    The use of sintered tungsten alloy slugs as absorber in the ATLAS Forward Calorimeter (FCAL) raised concern that it could possibly poison the liquid argon during the detector operation in the hard radiation environment expected at LHC. A vacuum container filled with tungsten slugs was exposed to the fast neutron fluence of 1.5$\\cdot$10$^{16}$~n~cm$^{-2}$ at the IBR-30 reactor of JINR, Dubna. The residual gas pressure was analysed. The study was completed by mass spectrometer measurements. An upper limit value of 0.1~ppm was determined for the pollution of liquid argon in FCAL due to outgassing from tungsten slugs under irradiation.

  14. Present status and future perspective of R and D on lead heavy metal-cooled fast reactors

    International Nuclear Information System (INIS)

    Takahashi, Minoru

    2007-01-01

    Since a lead heavy metal (lead-bismuth eutectic) is chemically inert and has higher boiling point compared to a sodium, a lead heavy metal-cooled fast reactor can be inherently safe and has good nuclear characteristics and is so suitable to a medium-small size of the reactor. R and D on corrosion of a lead heavy metal has been carried out in the world and this issue might be solved to choose specific corrosion resistant alloys for structural materials and fuel cans of a lead heavy metal-cooled reactor. This article reviews present status and future perspective on lead heavy metal-cooled fast reactors. (T. Tanaka)

  15. Effect of temperature on the crack resistance of a molybdenum alloy with 30% tungsten

    International Nuclear Information System (INIS)

    Uskov, E.I.; Babak, A.V.; D'yachkov, A.P.; Platonov, V.A.

    1986-01-01

    Results are presented for a study of the effect of temperature on the crack resistance of molybdenum alloy with 30% tungsten (Mo - 30% W), and data are presented for the crack resistance of commercial-purity molybdenum and tungsten obtained by power metallurgy in the temperature range 20-1800 C. It was found that the nature of failure for Mo-30% W alloy depends on test temperature; in the temperature range 20 C-T /SUP d/ /SUB br/ (upper boundary for the temperature range of the ductile to brittle transition), failure is unstable in nature, and at temperatures exceeding this transition, it occurs by steady main crack development

  16. Mechanical properties of molybdenum alloyed liquid phase-sintered tungsten-based composites

    International Nuclear Information System (INIS)

    Kemp, P.B.; German, R.M.

    1995-01-01

    Tungsten-based composites are fabricated from mixed elemental powders using liquid phase sintering, usually with a nickel-iron matrix. During sintering, the tungsten undergoes grain growth, leading to microstructure coarsening that lowers strength but increases ductility. Often the desire is to increase strength at the sacrifice of ductility, and historically, this has been performed by postsintering deformation. There has been considerable research on alloying to adjust the as-sintered mechanical properties to match those of swaged alloys. Prior reports cover many additions, seemingly including much of the periodic table. Unfortunately, many of the modified alloys proved disappointing, largely due to degraded strength at the tungsten-matrix interface. Of these modified alloys, the molybdenum-containing systems exhibit a promising combination of properties, cost, and processing ease. For example, the 82W-8Mo-7Ni-3Fe alloy gives a yield strength that is 34% higher than the equivalent 90W-7Ni-3Fe alloy (from 535 to 715 MPa) but with a 33% decrease in fracture elongation (from 30 to 20% elongation). This article reports on experiments geared to promoting improved properties in the W-Mo-Ni-Fe alloys. However, unlike the prior research which maintained a constant Ni + Fe content and varied the W:Mo ratio, this study considers the Mo:(Ni + Fe) ratio effect for 82, 90, and 93 wt pct W

  17. Method for determining the hardness of strain hardening articles of tungsten-nickel-iron alloy

    International Nuclear Information System (INIS)

    Wallace, S.A.

    1984-01-01

    The present invention is directed to a rapid nondestructive method for determining the extent of strain hardening in an article of tungsten-nickel-iron alloy. The method comprises saturating the article with a magnetic field from a permanent magnet, measuring the magnetic flux emanating from the article, comparing the measurements of the magnetic flux emanating from the article with measured magnetic fluxes from similarly shaped standards of the alloy with known amounts of strain hardening to determine the hardness

  18. Heavy metals in Mindhola river estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Rokade, M.A; Mandalia, A

    The heavy metal concentrations are studied along the Mindhola river estuary. Surface and bottom water samples were collected using Niskin Sampler. The sediment samples were collected using a Van Veen grab. The heavy metal concentration is estimated...

  19. The effects of alloying elements on microstructures and mechanical properties of tungsten inert gas welded AZ80 magnesium alloys joint

    Science.gov (United States)

    Li, Hui; Zhang, Jiansheng; Ding, Rongrong

    2017-11-01

    The effects of alloying elements on the macrostructures, microstructures and tensile strength of AZ80 Mg alloy weldments were studied in the present study. The results indicate that with the decrease of Al element content of filler wire, the welding defects of seam are gradually eliminated and the β-Mg17Al12 phases at α-Mg boundaries are refined and become discontinuous, which are beneficial to the improvement of tensile strength. With AZ31 Mg alloy filler wire, the maximum tensile strength of AZ80 weldment is 220 MPa and fracture occurs at the welding seam of joint. It is experimentally proved that robust AZ80 Mg alloy joints can be obtained by tungsten inert gas (TIG) welding process with AZ31 Mg alloy filler wire. However, further study is required to improve the microstructures and reduce welding defects of joint in order to further improve the joining strength of AZ80 Mg alloy joint.

  20. Recent progress on gas tungsten arc welding of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    King, J.F.; Grossbeck, M.L.; Goodwin, G.M.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    This is a progress report on a continuing research project to acquire a fundamental understanding of the metallurgical processes in the welding of vanadium alloys. It also has the goal of developing techniques for welding structural vanadium alloys. The alloy V-4Cr-4Ti is used as a representative alloy of the group; it is also the prime candidate vanadium alloy for the U.S. Fusion Program at the present time. However, other alloys of this class were used in the research as necessary. The present work focuses on recent findings of hydrogen embrittlement found in vanadium alloy welds. It was concluded that the atmosphere in the inert gas glove box was insufficient for welding 6mm thick vanadium alloy plates.

  1. Experimental and numerical simulations of ELM-like transient damage behaviors to different grade tungsten and tungsten alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiang, E-mail: xliu@swip.ac.cn [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Lian, Youyun; Chen, Lei; Chen, Zhenkui; Chen, Jiming; Duan, Xuru [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Fan, Jinlian [Central South University, Changsha 410083 (China); Song, Jiupeng [Xiamen Honglu Tungsten & Molybdenum Industry Co., Ltd, Xiamen (China)

    2015-08-15

    Transient heat loads, such as plasma disruptions and ELMs, could induce plastic deformations, cracking, melting, even fatigue cracks and creep of tungsten (W) surface. A high purity W, CVD-W coating, TiC dispersion strengthened and K doped tungsten alloys were tested in a 60 kW electron-beam facility by simulating the transient load events under different base temperatures. It was found that CVD-W, W-TiC and W-K alloys have higher crack thresholds than high purity W, meanwhile CVD-W is more sensitive to the crack disappearing at elevated base temperatures. On the other hand, repetitive pulse loading like ELMs can induce serious network cracks even the power density was quite lower than the crack threshold determined by a single shot. The ABAQUS code was used to simulate the crack behaviors of ITER grade pure W by a single shot and a FE-SAFE code was adopted to estimate the fatigue life under ELMs-like loads. A good agreement with experiment results was found.

  2. Heavy Metal Stars

    Science.gov (United States)

    2001-08-01

    atomic mass and hence, increasing positive charge of the nuclei, the electric repulsion between the nuclei becomes stronger and stronger. In fact, the fusion process only works up to a certain mass limit, corresponding to the element Iron [2]. All elements that are heavier than Iron cannot be produced via this path. But then, how were those heavy elements we now find on the Earth produced in the first place? From where comes the Zirconium in artificial diamonds, the Barium that colours fireworks, the Tungsten in the filaments in electric bulbs? Which process made the Lead in your car battery? Beyond iron The production of elements heavier than Iron takes place by adding neutrons to the atomic nuclei . These neutral particles do not feel any electrical repulsion from the charged nuclei. They can therefore easily approach them and thereby create heavier nuclei. This is indeed the way the heaviest chemical elements are built up. There are actually two different stellar environments where this process of "neutron capture" can happen. One place where this process occurs is inside very massive stars when they explode as supernovae . In such a dramatic event, the build-up proceeds very rapidly, via the so-called "r-process" ( "r" for rapid ). The AGB stars But not all heavy elements are created in such an explosive way. A second possibility follows a more "peaceful" road. It takes place in rather normal stars, when they burn their Helium towards the end of their lives. In the so-called "s-process" ( "s" for slow ), heavier elements are then produced by a rather gentle addition of neutral neutrons to atomic nuclei. In fact, roughly half of all the elements heavier than Iron are believed to be synthesized by this process during the late evolutionary phases of stars. This process takes place during a specific stage of stellar evolution, known as the "AGB" phase [3]. It occurs just before an old star expels its gaseous envelope into the surrounding interstellar space and sometime

  3. Micromycetes sensitiveness to heavy metals

    Directory of Open Access Journals (Sweden)

    O. N. Korinovskaya

    2011-07-01

    Full Text Available The sensitivity of 33 micromycete species to nitric compounds of copper, lead, zinc, nickel and cadmium has been determined. Absidia butleri Lendn, Mortierella vanesae Dixon-Stewart, Cunninghamella echinulata Thaxte, Curvularia tuberculata Jain, Cladosporium cladosporiodes (Fresen G. A. de Vries and Fusarium solani (C. Mart. Appel et Wollenw are sensitive to minimal content of the heavy metals (0.75 of maximum permissible concentration (MPC in the growth medium. At the same time Trixoderma longibrachiatiim Rifai, Alternaria alternatа (Fr. Keissl and Penicillium sp. 4 demonstrated moderate growth under maximal concentration (50 MPC. It is determined that minimal content of the heavy metals in the initial stage of influence (up to 48 h promotes growth of only Fusarium oxysporum E. F. Sm. et Swingle, while retards growth of the other species.

  4. The role of tungsten in the change of interatomic bond in Nb-W alloy

    International Nuclear Information System (INIS)

    Arkharov, V.I.; Samojlenko, Z.A.; Darovskikh, E.G.

    1982-01-01

    To study the chemical inhomogeneity and the peculiarities in electronic structure of solid solutions in fracture region, the X-ray spectral studies of niobium-tungsten alloys with 0.5; 1.0; 12.0; 13.6; 23.g mass % W have been carried out. The W concentration changes on the fracture and the difference in the electron energy distribution in the 4d-band in comparison between the fracture and mocrosection are determined. The niobium doping with tungsten is shown to be accompanied by the increase in the fraction of locally bound electrons as compared to the collectivized one. Alloys with 12-13% W are the most homogeneous in composition and electrons energy state. This state is characterized by features the increased number of electrons with noncompensated spins in intercrystalline boundaries as compared to a crystallite thickness. These alloys have homogeneous properties in sample microvolumes and large interatomic binding force

  5. Heavy metals in sea turtles

    Energy Technology Data Exchange (ETDEWEB)

    Witkowski, S.A. (Millersville State College, PA); Frazier, J.G.

    1982-07-01

    Bone and barnacle samples from sea turtles (Hepidochelys olivacea) in Ecuador were analyzed for manganese, iron, copper, zinc and lead. Analysis was performed by flame atomic absorption spectroscopy. Results show that zinc and iron levels in bone and barnacles were greater than copper, manganese and lead levels. The significance of the findings is difficult to interpret because so little is known about baseline levels and physiological effects of heavy metals in the animals. (JMT)

  6. Micromycetes sensitiveness to heavy metals

    OpenAIRE

    O. N. Korinovskaya; V. N. Gryshko

    2011-01-01

    The sensitivity of 33 micromycete species to nitric compounds of copper, lead, zinc, nickel and cadmium has been determined. Absidia butleri Lendn, Mortierella vanesae Dixon-Stewart, Cunninghamella echinulata Thaxte, Curvularia tuberculata Jain, Cladosporium cladosporiodes (Fresen) G. A. de Vries and Fusarium solani (C. Mart.) Appel et Wollenw are sensitive to minimal content of the heavy metals (0.75 of maximum permissible concentration (MPC)) in the growth medium. At the same time Trixoderm...

  7. Powder metallurgical processing of self-passivating tungsten alloys for fusion first wall application

    International Nuclear Information System (INIS)

    López-Ruiz, P.; Ordás, N.; Iturriza, I.; Walter, M.; Gaganidze, E.; Lindig, S.; Koch, F.; García-Rosales, C.

    2013-01-01

    Self-passivating tungsten based alloys are expected to provide a major safety advantage compared to pure tungsten, presently the main candidate material for first wall armour of future fusion reactors. In case of a loss of coolant accident with simultaneous air ingress, a protective oxide scale will be formed on the surface of W avoiding the formation of volatile and radioactive WO 3 . Bulk WCr12Ti2.5 alloys were manufactured by mechanical alloying (MA) and hot isostatic pressing (HIP), and their properties compared to bulk WCr10Si10 alloys from previous work. The MA parameters were adjusted to obtain the best balance between lowest possible amount of contaminants and effective alloying of the elemental powders. After HIP, a density >99% is achieved for the WCr12Ti2.5 alloy and a very fine and homogeneous microstructure with grains in the submicron range is obtained. Unlike the WCr10Si10 material, no intergranular ODS phase inhibiting grain growth was detected. The thermal and mechanical properties of the WCr10Si10 material are dominated by the silicide (W,Cr) 5 Si 3 ; it shows a sharp ductile-to brittle transition in the range 1273–1323 K. The thermal conductivity of the WCr12Ti2.5 alloy is close to 50 W/mK in the temperature range of operation; it exhibits significantly higher strength and lower DBTT – around 1170 K – than the WCr10Si10 material

  8. Processing and production of molybdenum and tungsten alloys

    International Nuclear Information System (INIS)

    Hagel, W.C.; Shields, J.A. Jr.; Tuominen, S.M.

    1984-01-01

    The technological means to produce and process Mo and W alloys are summarized because for many Mo and W alloy systems the mechanical properties can be optimized only by thermomechanical processing requiring production and processing capabilities that are not widely available. First, the producers of commercial Mo and W alloys are presented along with currently available product forms. Second, currently disclosed standard capabilities of producers and processors in the United States are presented. 56 references, 13 figures, 9 tables

  9. Tungsten - rhenium alloys wire: overview of thermomechanical processing and properties data

    International Nuclear Information System (INIS)

    Bryskin, B.

    2001-01-01

    The scope of this study encompasses the compositional modifications of the tungsten-rhenium dual system (W-3/5 Re up to W-27 Re) as well as some of the tungsten-molybdenum-rhenium ternary system. The alloys of interest are considered with a specific representation of powder metallurgy route based on doped or undoped tungsten vs. vacuum melted materials. This paper constitutes an in-depth review of structural and mechanical properties and systematic compilation of challenges necessary to provide the quality consistency of severely drawn filaments. The issue of thermomechanical processing trends is addressed as an important part of W-Re fabrication technology to achieve further improvement in design properties of rod and wire. (author)

  10. Biosolids and heavy metals in soils

    Directory of Open Access Journals (Sweden)

    Silveira Maria Lucia Azevedo

    2003-01-01

    Full Text Available The application of sewage sludge or biosolids on soils has been widespread in agricultural areas. However, depending on their characteristics, they may cause increase in heavy metal concentration of treated soils. In general, domestic biosolids have lower heavy metal contents than industrial ones. Origin and treatment method of biosolids may markedly influence their characteristics. The legislation that controls the levels of heavy metal contents in biosolids and the maximum concentrations in soils is still controversial. In the long-term, heavy metal behavior after the and of biosolid application is still unknown. In soils, heavy metals may be adsorbed via specific or non-specific adsorption reactions. Iron oxides and organic matter are the most important soil constituents retaining heavy metals. The pH, CEC and the presence of competing ions also affect heavy metal adsorption and speciation in soils. In solution, heavy metals can be present either as free-ions or complexed with organic and inorganic ligands. Generally, free-ions are more relevant in environmental pollution studies since they are readily bioavailable. Some computer models can estimate heavy metal activity in solution and their ionic speciation. Thermodynamic data (thermodynamic stability constant, total metal and ligand concentrations are used by the GEOCHEM-PC program. This program allows studying heavy metal behavior in solution and the effect of changes in the conditions, such as pH and ionic strength and the application of organic and inorganic ligands caused by soil fertilization.

  11. Correlation of microstructure with dynamic deformation behavior and penetration performance of tungsten heavy alloys fabricated by mechanical alloying

    Science.gov (United States)

    Kim, Dong-Kuk; Lee, Sunghak; Ryu, Ho Jin; Hyunghong, Soon; Noh, Joon-Woong

    2000-10-01

    In this study, tungsten heavy alloy specimens were fabricated by mechanical alloying (MA), and their dynamic torsional properties and penetration performance were investigated. Dynamic torsional tests were conducted on the specimens fabricated with different sintering temperatures after MA, and then the test data were compared with those of a conventionally processed specimen. Refinement of tungsten particles was obtained after MA, but contiguity was seriously increased, thereby leading to low ductility and impact energy. Specimens in which both particle size and contiguity were simultaneously reduced by MA and two-step sintering and those having higher matrix fraction by partial MA were successfully fabricated. The dynamic test results indicated that the formation of adiabatic shear bands was expected because of the plastic localization at the central area of the gage section. Upon highspeed impact testing of these specimens, self-sharpening was promoted by the adiabatic shear band formation, but their penetration performance did not improve since much of kinetic energy of the penetrators was consumed for the microcrack formation due to interfacial debonding and cleavage fracture of tungsten particles. In order to improve penetration performance as well as to achieve selfsharpening by applying MA, conditions of MA and sintering process should be established so that alloy densification, particle refinement, and contiguity reduction can be simultaneously achieved.

  12. High density tungsten-nickel-iron-cobalt alloys having improved hardness and method for making same

    International Nuclear Information System (INIS)

    Penrice, T.W.; Bost, J.

    1988-01-01

    This patent describes the process of making high density alloy containing about 85 to 98 weight percent tungsten and the balance of the alloy being essentially a binder of nickel, iron and cobalt, and wherein the cobalt is present in an amount within the range of about 5 to 47.5 weight percent of the binder, comprising: blending powders of the tungsten, nickel, iron and cobalt into a homogeneous composition, compacting the homogeneous composition into a shaped article, heating the shaped article to a temperature and for a time sufficient to sinter the article, subjecting the sintered article to a temperature sufficient to enable the intermetallic phase formed at the matrix to tungsten interface to diffuse into the gamma austenitic phase whereby the alpha tungsten/gamma austenite boundaries are essentially free of such intermetallic phase, quenching the article, and swaging the article to a reduction in area of about 5 to 40 percent, the article having improved mechanical properties, including improved tensile strength and hardness while maintaining suitable ductility for subsequent working thereof

  13. Surface studies of Os Re W alloy-coated impregnated tungsten cathodes

    International Nuclear Information System (INIS)

    Ares Fang, C.S.; Maloney, C.E.

    1990-01-01

    Impregnated tungsten cathodes half-coated with Re/W (or Os/W) alloy and Os Re W alloy at right angles were studied to compare the effects of Os Re W alloy coatings on the electron emission and emission mechanisms. Constant surface metal compositions of 32% Os--29% Re--39% W and 35% Os--26% Re--39% W were obtained from the activated surfaces initially coated with 40% Os--40% Re--20% W and 35% Os--45% Re--20% W alloys, respectively. Thermionic emission microscopy measurements showed that the Os Re W alloy-coated surface gives an average effective work function of 0.29, 0.08, and 0.03 eV lower than the uncoated, Re/W and Os/W alloy-coated surfaces. An effective work function of 1.73 eV was obtained from an activated Os Re W alloy surface. Auger studies exhibited a smaller BaO coverage and a higher barium coverage in excess of BaO stoichiometry on the Os Re W alloy-coated surface compared to the uncoated, Re/W and Os/W alloy-coated surfaces

  14. Tensile Flow Behavior of Tungsten Heavy Alloys Produced by CIPing and Gelcasting Routes

    Science.gov (United States)

    Panchal, Ashutosh; Ravi Kiran, U.; Nandy, T. K.; Singh, A. K.

    2018-06-01

    Present work describes the flow behavior of tungsten heavy alloys with nominal compositions 90W-7Ni-3Fe, 93W-4.9Ni-2.1Fe, and 95W-3.5Ni-1.5Fe (wt pct) produced by CIPing and gelcasting routes. The overall microstructural features of gelcasting are finer than those of CIPing alloys. Both the grain size of W and corresponding contiguity values increase with increase in W content in the present alloys. The volume fraction of matrix phase decreases with increase in W content in both the alloys. The lattice parameter values of the matrix phase also increase with increase in W content. The yield strength ( σ YS) continuously increases with increase in W content in both the alloys. The σ YS values of CIPing alloys are marginally higher than those of gelcasting at constant W. The ultimate tensile strength ( σ UTS) and elongation values are maximum at intermediate W content. Present alloys exhibit two slopes in true stress-true plastic strain curves in low and high strain regimes and follow a characteristic Ludwigson relation. The two slopes are associated with two deformation mechanisms that are occurring during tensile deformation. The overall nature of differential curves of all the alloys is different and these curves contain three distinctive stages of work hardening (I, II, and III). This suggests varying deformation mechanisms during tensile testing due to different volume fractions of constituent phases. The slip is the predominant deformation mechanism of the present alloys during tensile testing.

  15. Oil Spill Related Heavy Metal: A Review

    International Nuclear Information System (INIS)

    Ahmad Dasuki Mustafa; Hafizan Juahir; Kamaruzzaman Yunus; Mohammad Azizi Amran; Che Noraini Che Hasnam; Fazureen Azaman; Ismail Zainal Abidin; Syahril Hirman Azmee; Nur Hishaam Sulaiman

    2015-01-01

    Oil spill occurs every day worldwide and oil contamination is a significant contributor for the higher levels of heavy metals in the environment. This study is purposely to summarize the heavy metals which significant to major oil spill incidents around the world and effects of toxic metals to human health. The study performed a comprehensive review of relevant scientific journal articles and government documents concerning heavy metals contamination and oil spills. Overall, the heavy metals most frequently been detected in oil spill related study where Pb>Ni>V>Zn>Cd and caused many effects to human health especially cancer. In conclusion, the comparison of heavy metal level between the post - spill and baseline levels must be done, and implementation of continuous monitoring of heavy metal. In addition, the result based on the strategies must be transparent to public in order to maintaining human health. (author)

  16. Study of structure and residual stresses in cold rotary swaged tungsten heavy alloy

    Czech Academy of Sciences Publication Activity Database

    Kunčická, L.; Kocich, R.; Hervoches, Charles; Macháčková, A.

    2017-01-01

    Roč. 705, č. 9 (2017), s. 25-31 ISSN 0921-5093 R&D Projects: GA MŠk LM2015056 Institutional support: RVO:61389005 Keywords : Tungsten heavy alloy * residual stresses * neutron scattering * electron microscopy * work hardening Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.094, year: 2016

  17. Divergent biology of facultative heavy metal plants.

    Science.gov (United States)

    Bothe, Hermann; Słomka, Aneta

    2017-12-01

    Among heavy metal plants (the metallophytes), facultative species can live both in soils contaminated by an excess of heavy metals and in non-affected sites. In contrast, obligate metallophytes are restricted to polluted areas. Metallophytes offer a fascinating biology, due to the fact that species have developed different strategies to cope with the adverse conditions of heavy metal soils. The literature distinguishes between hyperaccumulating, accumulating, tolerant and excluding metallophytes, but the borderline between these categories is blurred. Due to the fact that heavy metal soils are dry, nutrient limited and are not uniform but have a patchy distribution in many instances, drought-tolerant or low nutrient demanding species are often regarded as metallophytes in the literature. In only a few cases, the concentrations of heavy metals in soils are so toxic that only a few specifically adapted plants, the genuine metallophytes, can cope with these adverse soil conditions. Current molecular biological studies focus on the genetically amenable and hyperaccumulating Arabidopsis halleri and Noccaea (Thlaspi) caerulescens of the Brassicaceae. Armeria maritima ssp. halleri utilizes glands for the excretion of heavy metals and is, therefore, a heavy metal excluder. The two endemic zinc violets of Western Europe, Viola lutea ssp. calaminaria of the Aachen-Liège area and Viola lutea ssp. westfalica of the Pb-Cu-ditch of Blankenrode, Eastern Westphalia, as well as Viola tricolor ecotypes of Eastern Europe, keep their cells free of excess heavy metals by arbuscular mycorrhizal fungi which bind heavy metals. The Caryophyllaceae, Silene vulgaris f. humilis and Minuartia verna, apparently discard leaves when overloaded with heavy metals. All Central European metallophytes have close relatives that grow in areas outside of heavy metal soils, mainly in the Alps, and have, therefore, been considered as relicts of the glacial epoch in the past. However, the current

  18. Poisoning of domestic animals with heavy metals

    Directory of Open Access Journals (Sweden)

    Velev Romel

    2009-01-01

    Full Text Available The term heavy metal refers to a metal that has a relatively high density and is toxic for animal and human organism at low concentrations. Heavy metals are natural components of the Earth's crust. They cannot be degraded or destroyed. To a small extent they enter animal organism via food, drinking water and air. Some heavy metals (e.g cooper, iron, chromium, zinc are essential in very low concentrations for the survival of all forms of life. These are described as essential trace elements. However, when they are present in greater quantities, like the heavy metals lead, cadmium and mercury which are already toxic in very low concentrations, they can cause metabolic anomalies or poisoning. Heavy metal poisoning of domestic animals could result, for instance, from drinking-water contamination, high ambient air concentrations near emission sources, or intake via the food chain. Heavy metals are dangerous because they tend to bioaccumulate in a biological organism over time. Manifestation of toxicity of individual heavy metals varies considerably, depending on dose and time of exposure, species, gender and environmental and nutritional factors. Large differences exist between the effects of a single exposure to a high concentration, and chronic exposures to lower doses. The aim of this work is to present the source of poisoning and toxicity of some heavy metals (lead, mercury, cadmium, thallium, arsenic, as well as new data about effects of those heavy metals on the health of domestic animals. .

  19. Recent progress on gas tungsten arc welding of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Grossbeck, M.L.; King, J.F.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)] [and others

    1997-08-01

    Emphasis has been placed on welding 6.4 mm plate, primarily by gas tungsten arc (GTA) welding. The weld properties were tested using blunt notch Charpy testing to determine the ductile to brittle transition temperature (DBTT). Erratic results were attributed to hydrogen and oxygen contamination of the welds. An improved gas clean-up system was installed on the welding glove box and the resulting high purity welds had Charpy impact properties similar to those of electron beam welds with similar grain size. A post-weld heat treatment (PWHT) of 950{degrees}C for two hours did not improve the properties of the weld in cases where low concentrations of impurities were attained. Further improvements in the gas clean-up system are needed to control hydrogen contamination.

  20. Influence of grain boundaries on the fracture toughness of tungsten alloys

    International Nuclear Information System (INIS)

    Gludovatz, B.; Faleschini, M.; Pippan, R.; Hoffmann, A.

    2007-01-01

    Full text of publication follows: Tungsten and tungsten alloys are possible candidates for future fusion reactors because of their high melting points, high thermal conductivity and their high erosion resistance. Since these materials have a body-centered cubic (bcc) structure, they show a typical change in fracture behaviour from brittle at low temperatures to ductile at high temperatures. For that reason the fracture behaviour of pure tungsten (W), potassium doped tungsten (AKS) and tungsten with 1 wt% La 2 O 3 (WL10) was studied, taking into account the influence of temperature and fabrication condition. Especially AKS has been studied to investigate the longitudinal splitting of the AKS-wires, the crack propagation direction with the lowest fracture toughness. This alloy subjected to intense deformation leads to a material with an elongated grain structure after recrystallization because of the potassium bubbles. Fracture toughness has been investigated by means of 3-point bending (3PB) specimens, double cantilever beam (DCB) specimens and compact tension (CT) specimens. Tests were performed in the range -196 deg. C to more than 1000 deg. C. Though all these materials show an expected increase in fracture toughness with increasing temperature, influences like texture, chemical composition, grain boundary segregation and dislocation density seem to have an extreme influence on the obtained results. These influences can especially be seen in the fracture behaviour and morphology, where two kinds of fracture can occur: on one hand the trans-crystalline and on the other hand the intercrystalline fracture. Therefore techniques like electron backscatter diffraction, auger electron spectroscopy and X-ray line profile analysis were used to determine the parameter influencing fracture toughness. Also new testing techniques have been devised and successfully applied. Additional tests like an 'in-situ EBSD' technique for investigating the formation of dislocations during

  1. Tungsten wire-nickel base alloy composite development

    Science.gov (United States)

    Brentnall, W. D.; Moracz, D. J.

    1976-01-01

    Further development and evaluation of refractory wire reinforced nickel-base alloy composites is described. Emphasis was placed on evaluating thermal fatigue resistance as a function of matrix alloy composition, fabrication variables and reinforcement level and distribution. Tests for up to 1,000 cycles were performed and the best system identified in this current work was 50v/o W/NiCrAlY. Improved resistance to thermal fatigue damage would be anticipated for specimens fabricated via optimized processing schedules. Other properties investigated included 1,093 C (2,000 F) stress rupture strength, impact resistance and static air oxidation. A composite consisting of 30v/o W-Hf-C alloy fibers in a NiCrAlY alloy matrix was shown to have a 100-hour stress rupture strength at 1,093 C (2,000 F) of 365 MN/square meters (53 ksi) or a specific strength advantage of about 3:1 over typical D.S. eutectics.

  2. Powder metallurgical processing of self-passivating tungsten alloys for fusion first wall application

    Energy Technology Data Exchange (ETDEWEB)

    López-Ruiz, P.; Ordás, N.; Iturriza, I. [CEIT and Tecnun (University of Navarra), E-20018 San Sebastian (Spain); Walter, M.; Gaganidze, E. [Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen (Germany); Lindig, S.; Koch, F. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); García-Rosales, C., E-mail: cgrosales@ceit.es [CEIT and Tecnun (University of Navarra), E-20018 San Sebastian (Spain)

    2013-11-15

    Self-passivating tungsten based alloys are expected to provide a major safety advantage compared to pure tungsten, presently the main candidate material for first wall armour of future fusion reactors. In case of a loss of coolant accident with simultaneous air ingress, a protective oxide scale will be formed on the surface of W avoiding the formation of volatile and radioactive WO{sub 3}. Bulk WCr12Ti2.5 alloys were manufactured by mechanical alloying (MA) and hot isostatic pressing (HIP), and their properties compared to bulk WCr10Si10 alloys from previous work. The MA parameters were adjusted to obtain the best balance between lowest possible amount of contaminants and effective alloying of the elemental powders. After HIP, a density >99% is achieved for the WCr12Ti2.5 alloy and a very fine and homogeneous microstructure with grains in the submicron range is obtained. Unlike the WCr10Si10 material, no intergranular ODS phase inhibiting grain growth was detected. The thermal and mechanical properties of the WCr10Si10 material are dominated by the silicide (W,Cr){sub 5}Si{sub 3}; it shows a sharp ductile-to brittle transition in the range 1273–1323 K. The thermal conductivity of the WCr12Ti2.5 alloy is close to 50 W/mK in the temperature range of operation; it exhibits significantly higher strength and lower DBTT – around 1170 K – than the WCr10Si10 material.

  3. In vivo corrosion, tumor outcome, and microarray gene expression for two types of muscle-implanted tungsten alloys

    International Nuclear Information System (INIS)

    Schuster, B.E.; Roszell, L.E.; Murr, L.E.; Ramirez, D.A.; Demaree, J.D.; Klotz, B.R.; Rosencrance, A.B.; Dennis, W.E.; Bao, W.; Perkins, E.J.; Dillman, J.F.; Bannon, D.I.

    2012-01-01

    Tungsten alloys are composed of tungsten microparticles embedded in a solid matrix of transition metals such as nickel, cobalt, or iron. To understand the toxicology of these alloys, male F344 rats were intramuscularly implanted with pellets of tungsten/nickel/cobalt, tungsten/nickel/iron, or pure tungsten, with tantalum pellets as a negative control. Between 6 and 12 months, aggressive rhabdomyosarcomas formed around tungsten/nickel/cobalt pellets, while those of tungsten/nickel/iron or pure tungsten did not cause cancers. Electron microscopy showed a progressive corrosion of the matrix phase of tungsten/nickel/cobalt pellets over 6 months, accompanied by high urinary concentrations of nickel and cobalt. In contrast, non-carcinogenic tungsten/nickel/iron pellets were minimally corroded and urinary metals were low; these pellets having developed a surface oxide layer in vivo that may have restricted the mobilization of carcinogenic nickel. Microarray analysis of tumors revealed large changes in gene expression compared with normal muscle, with biological processes involving the cell cycle significantly up‐regulated and those involved with muscle development and differentiation significantly down‐regulated. Top KEGG pathways disrupted were adherens junction, p53 signaling, and the cell cycle. Chromosomal enrichment analysis of genes showed a highly significant impact at cytoband 7q22 (chromosome 7) which included mouse double minute (MDM2) and cyclin‐dependant kinase (CDK4) as well as other genes associated with human sarcomas. In conclusion, the tumorigenic potential of implanted tungsten alloys is related to mobilization of carcinogenic metals nickel and cobalt from corroding pellets, while gene expression changes in the consequent tumors are similar to radiation induced animal sarcomas as well as sporadic human sarcomas. -- Highlights: ► Tungsten/nickel/cobalt, tungsten/nickel/iron, and pure tungsten were studied. ► Male Fischer rats implanted with

  4. In vivo corrosion, tumor outcome, and microarray gene expression for two types of muscle-implanted tungsten alloys

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, B.E. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, B434 Mulberry Road, Aberdeen Proving Ground, MD 21005-5609 (United States); Roszell, L.E. [U.S. Army Institute of Public Health, 5158 Blackhawk Road, Aberdeen Proving Ground, MD 21010‐5403 (United States); Murr, L.E.; Ramirez, D.A. [Department of Metallurgical and Materials Engineering, University of Texas, El Paso, TX 79968 (United States); Demaree, J.D. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, B434 Mulberry Road, Aberdeen Proving Ground, MD 21005-5609 (United States); Klotz, B.R. [Dynamic Science Inc., Aberdeen Proving Ground, MD 21005‐5609 (United States); Rosencrance, A.B.; Dennis, W.E. [U.S. Army Center for Environmental Health Research, Department of Chemistry, Ft. Detrick, MD 21702‐5010 (United States); Bao, W. [SAS Institute, Inc. SAS Campus Drive, Cary, NC 27513 (United States); Perkins, E.J. [U.S. Army Engineer Research and Development Center, 3909 Hall Ferry Road, Vicksburg MS 39180 (United States); Dillman, J.F. [U.S. Army Medical Research Institute of Chemical Defense, 3100 Ricketts Point Road, Aberdeen Proving Ground, MD 21010‐5400 (United States); Bannon, D.I., E-mail: desmond.bannon@us.army.mil [U.S. Army Institute of Public Health, 5158 Blackhawk Road, Aberdeen Proving Ground, MD 21010‐5403 (United States)

    2012-11-15

    Tungsten alloys are composed of tungsten microparticles embedded in a solid matrix of transition metals such as nickel, cobalt, or iron. To understand the toxicology of these alloys, male F344 rats were intramuscularly implanted with pellets of tungsten/nickel/cobalt, tungsten/nickel/iron, or pure tungsten, with tantalum pellets as a negative control. Between 6 and 12 months, aggressive rhabdomyosarcomas formed around tungsten/nickel/cobalt pellets, while those of tungsten/nickel/iron or pure tungsten did not cause cancers. Electron microscopy showed a progressive corrosion of the matrix phase of tungsten/nickel/cobalt pellets over 6 months, accompanied by high urinary concentrations of nickel and cobalt. In contrast, non-carcinogenic tungsten/nickel/iron pellets were minimally corroded and urinary metals were low; these pellets having developed a surface oxide layer in vivo that may have restricted the mobilization of carcinogenic nickel. Microarray analysis of tumors revealed large changes in gene expression compared with normal muscle, with biological processes involving the cell cycle significantly up‐regulated and those involved with muscle development and differentiation significantly down‐regulated. Top KEGG pathways disrupted were adherens junction, p53 signaling, and the cell cycle. Chromosomal enrichment analysis of genes showed a highly significant impact at cytoband 7q22 (chromosome 7) which included mouse double minute (MDM2) and cyclin‐dependant kinase (CDK4) as well as other genes associated with human sarcomas. In conclusion, the tumorigenic potential of implanted tungsten alloys is related to mobilization of carcinogenic metals nickel and cobalt from corroding pellets, while gene expression changes in the consequent tumors are similar to radiation induced animal sarcomas as well as sporadic human sarcomas. -- Highlights: ► Tungsten/nickel/cobalt, tungsten/nickel/iron, and pure tungsten were studied. ► Male Fischer rats implanted with

  5. Self-passivating bulk tungsten-based alloys manufactured by powder metallurgy

    Science.gov (United States)

    López-Ruiz, P.; Ordás, N.; Lindig, S.; Koch, F.; Iturriza, I.; García-Rosales, C.

    2011-12-01

    Self-passivating tungsten-based alloys are expected to provide a major safety advantage compared to pure tungsten, which is at present the main candidate material for the first wall armour of future fusion reactors. WC10Si10 alloys were manufactured by mechanical alloying (MA) in a Planetary mill and subsequent hot isostatic pressing (HIP), achieving densities above 95%. Different MA conditions were studied. After MA under optimized conditions, a core with heterogeneous microstructure was found in larger powder particles, resulting in the presence of some large W grains after HIP. Nevertheless, the obtained microstructure is significantly refined compared to previous work. First MA trials were also performed on the Si-free system WCr12Ti2.5. In this case a very homogeneous structure inside the powder particles was obtained, and a majority ternary metastable bcc phase was found, indicating that almost complete alloying occurred. Therefore, a very fine and homogeneous microstructure can be expected after HIP in future work.

  6. Self-passivating bulk tungsten-based alloys manufactured by powder metallurgy

    International Nuclear Information System (INIS)

    López-Ruiz, P; Ordás, N; Iturriza, I; García-Rosales, C; Lindig, S; Koch, F

    2011-01-01

    Self-passivating tungsten-based alloys are expected to provide a major safety advantage compared to pure tungsten, which is at present the main candidate material for the first wall armour of future fusion reactors. WC10Si10 alloys were manufactured by mechanical alloying (MA) in a Planetary mill and subsequent hot isostatic pressing (HIP), achieving densities above 95%. Different MA conditions were studied. After MA under optimized conditions, a core with heterogeneous microstructure was found in larger powder particles, resulting in the presence of some large W grains after HIP. Nevertheless, the obtained microstructure is significantly refined compared to previous work. First MA trials were also performed on the Si-free system WCr12Ti2.5. In this case a very homogeneous structure inside the powder particles was obtained, and a majority ternary metastable bcc phase was found, indicating that almost complete alloying occurred. Therefore, a very fine and homogeneous microstructure can be expected after HIP in future work.

  7. Process for fabricating articles of tungsten-nickel-iron alloy

    Science.gov (United States)

    Northcutt, Jr., Walter G.; Snyder, Jr., William B.

    1976-01-01

    A high density W--Ni--Fe alloy of composition 85-96% by weight W and the remainder Ni and Fe in a wt. ratio of 5:5-8:2 having enhanced mechanical properties is prepared by compacting the mixed powders, sintering the compact in reducing atmosphere to near theoretical density followed by further sintering at a temperature where a liquid phase is present, vacuum annealing, and cold working to achieve high uniform hardness.

  8. Process for fabricating articles of tungsten--nickel--iron alloy

    International Nuclear Information System (INIS)

    Northcutt, W.G. Jr.; Snyder, W.B. Jr.

    1976-01-01

    A high density W--Ni--Fe alloy of composition 85 to 96 percent by weight W and the remainder Ni and Fe in a wt. ratio of 5:5 to 8:2 having enhanced mechanical properties is prepared by compacting the mixed powders, sintering the compact in reducing atmosphere to near theoretical density followed by further sintering at a temperature where a liquid phase is present, vacuum annealing, and cold working to achieve high uniform hardness. 7 claims

  9. Vacuum hot-pressed beryllium and TiC dispersion strengthened tungsten alloy developments for ITER and future fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiang, E-mail: xliu@swip.ac.cn [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Chen, Jiming; Lian, Youyun; Wu, Jihong; Xu, Zengyu; Zhang, Nianman; Wang, Quanming; Duan, Xuro [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Wang, Zhanhong; Zhong, Jinming [Northwest Rare Metal Material Research Institute, CNMC, Ningxia Orient Group Co. Ltd.,No.119 Yejin Road, Shizuishan City, Ningxia,753000 (China)

    2013-11-15

    Beryllium and tungsten have been selected as the plasma facing materials of the ITER first wall (FW) and divertor chamber, respectively. China, as a participant in ITER, will share the manufacturing tasks of ITER first-wall mockups with the European Union and Russia. Therefore ITER-grade beryllium has been developed in China and a kind of vacuum hot-pressed (VHP) beryllium, CN-G01, was characterized for both physical, and thermo-mechanical properties and high heat flux performance, which indicated an equivalent performance to U.S. grade S-65C beryllium, a reference grade beryllium of ITER. Consequently CN-G01 beryllium has been accepted as the armor material of ITER-FW blankets. In addition, a modification of tungsten by TiC dispersion strengthening was investigated and a W–TiC alloy with TiC content of 0.1 wt.% has been developed. Both surface hardness and recrystallization measurements indicate its re-crystallization temperature approximately at 1773 K. Deuterium retention and thermal desorption behaviors of pure tungsten and the TiC alloy were also measured by deuterium ion irradiation of 1.7 keV energy to the fluence of 0.5–5 × 10{sup 18} D/cm{sup 2}; a main desorption peak at around 573 K was found and no significant difference was observed between pure tungsten and the tungsten alloy. Further characterization of the tungsten alloy is in progress.

  10. Heavy metals in packaging : a literature survey

    NARCIS (Netherlands)

    van Putten EM; IMG

    2011-01-01

    The use of the heavy metals cadmium, mercury, chromium and lead in packaging is forbidden internationally for some years because these substances are harmful to the environment. In 2002 the Dutch national Inspectorate for the Environment determined the presence of heavy metals in packaging for

  11. ASSESSMENT OF HEAVY METALS AND CRUDE PROTEIN ...

    African Journals Online (AJOL)

    UNICORN

    to quantify heavy metals (Cu, Zn, Pb and Cd) and crude protein content of these species that are sold in ... in protein, omega 3 and low fat content. Furthermore ... high levels of cadmium can cause kidney and liver damage in man [6]. Motivation .... analysis. Determination of heavy metals in the edible tissues of the organisms.

  12. Microbial treatment of heavy metal leachates

    International Nuclear Information System (INIS)

    Alvarez Aliaga, M. T.

    2009-01-01

    Ore-mining metallurgy and other industrial activities represent the source of heavy metal and radionuclide contamination in terrestrial and aquatic environments. Physico-chemical processes are employed for heavy metal removal from industrial wastewaters. However, limitations due to the cost-effectiveness and use of contaminating reagents make these processes not environmentally friendly. (Author)

  13. Behaviour of heavy metals in soils

    NARCIS (Netherlands)

    Harmsen, K.

    1977-01-01

    Fractions of Zn, Cd, Cu, Pb, Fe and Mn extractable with water, a salt solution and dilute acid, and residual fractions were determined in soils with raised contents of heavy metals, near zinc smelters, along a river formerly discharging heavy metals, and in a sewage farm. Special attention

  14. Heavy metals precipitation in sewage sludge

    NARCIS (Netherlands)

    Marchioretto, M.M.; Rulkens, W.H.; Bruning, H.

    2005-01-01

    There is a great need for heavy metal removal from strongly metal-polluted sewage sludges. One of the advantages of heavy metal removal from this type of sludge is the possibility of the sludge disposal to landfill with reduced risk of metals being leached to the surface and groundwater. Another

  15. A review of soil heavy metal pollution from mines in China: pollution and health risk assessment.

    Science.gov (United States)

    Li, Zhiyuan; Ma, Zongwei; van der Kuijp, Tsering Jan; Yuan, Zengwei; Huang, Lei

    2014-01-15

    Heavy metal pollution has pervaded many parts of the world, especially developing countries such as China. This review summarizes available data in the literature (2005-2012) on heavy metal polluted soils originating from mining areas in China. Based on these obtained data, this paper then evaluates the soil pollution levels of these collected mines and quantifies the risks these pollutants pose to human health. To assess these potential threat levels, the geoaccumulation index was applied, along with the US Environmental Protection Agency (USEPA) recommended method for health risk assessment. The results demonstrate not only the severity of heavy metal pollution from the examined mines, but also the high carcinogenic and non-carcinogenic risks that soil heavy metal pollution poses to the public, especially to children and those living in the vicinity of heavily polluted mining areas. In order to provide key management targets for relevant government agencies, based on the results of the pollution and health risk assessments, Cd, Pb, Cu, Zn, Hg, As, and Ni are selected as the priority control heavy metals; tungsten, manganese, lead-zinc, and antimony mines are selected as the priority control mine categories; and southern provinces and Liaoning province are selected as the priority control provinces. This review, therefore, provides a comprehensive assessment of soil heavy metal pollution derived from mines in China, while identifying policy recommendations for pollution mitigation and environmental management of these mines. © 2013.

  16. Interfaces between Model Co-W-C Alloys with Various Carbon Contents and Tungsten Carbide

    Directory of Open Access Journals (Sweden)

    Igor Konyashin

    2018-03-01

    Full Text Available Interfaces between alloys simulating binders in WC-Co cemented carbides and tungsten carbide were examined on the micro-, nano-, and atomic-scale. The precipitation of fine WC grains and η-phase occurs at the interface of the alloy with the low carbon content. The precipitation of such grains almost does not occur in the alloy with the medium-low carbon content and does not take place in the alloy with the high carbon content. The formation of Co nanoparticles in the binder alloy with the medium-low carbon content was established. Interfaces in the alloy with the medium-low carbon content characterized by complete wetting with respect to WC and with the high carbon content characterized by incomplete wetting were examined at an atomic scale. The absence of any additional phases or carbon segregations at both of the interfaces was established. Thus, the phenomenon of incomplete wetting of WC by liquid binders with high carbon contents is presumably related to special features of the Co-based binder alloys oversaturated with carbon at sintering temperatures.

  17. Bioremoval of heavy metals by bacterial biomass.

    Science.gov (United States)

    Aryal, Mahendra; Liakopoulou-Kyriakides, Maria

    2015-01-01

    Heavy metals are among the most common pollutants found in the environment. Health problems due to the heavy metal pollution become a major concern throughout the world, and therefore, various treatment technologies such as reverse osmosis, ion exchange, solvent extraction, chemical precipitation, and adsorption are adopted to reduce or eliminate their concentration in the environment. Biosorption is a cost-effective and environmental friendly technique, and it can be used for detoxification of heavy metals in industrial effluents as an alternative treatment technology. Biosorption characteristics of various bacterial species are reviewed here with respect to the results reported so far. The role of physical, chemical, and biological modification of bacterial cells for heavy metal removal is presented. The paper evaluates the different kinetic, equilibrium, and thermodynamic models used in bacterial sorption of heavy metals. Biomass characterization and sorption mechanisms as well as elution of metal ions and regeneration of biomass are also discussed.

  18. Heavy metal uptake of Geosiphon pyriforme

    Energy Technology Data Exchange (ETDEWEB)

    Scheloske, Stefan E-mail: stefan.scheloske@mpi-hd.mpg.de; Maetz, Mischa; Schuessler, Arthur

    2001-07-01

    Geosiphon pyriforme represents the only known endosymbiosis between a fungus, belonging to the arbuscular mycorrhizal (AM) fungi, and cyanobacteria (blue-green algae). Therefore we use Geosiphon as a model system for the widespread AM symbiosis and try to answer some basic questions regarding heavy metal uptake or resistance of AM fungi. We present quantitative micro-PIXE measurements of a set of heavy metals (Cu, Cd, Tl, Pb) taken up by Geosiphon-cells. The uptake is studied as a function of the metal concentration in the nutrient solution and of the time Geosiphon spent in the heavy metal enriched medium. The measured heavy metal concentrations range from several ppm to some hundred ppm. Also the influence of the heavy metal uptake on the nutrition transfer of other elements will be discussed.

  19. Heavy Metal Blood Test: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/heavymetalbloodtest.html Heavy Metal Blood Test To use the sharing features ... this page, please enable JavaScript. What is a Heavy Metal Blood Test? A heavy metal blood test ...

  20. Toughness behaviour of tungsten-carbide-cobalt alloys

    International Nuclear Information System (INIS)

    Sigl, L.S.

    1985-05-01

    In the present work the mechanisms of crack propagation in technically important WC-Co alloys are investigated and a model describing the influence of microstructural parameters and of the mechanical properties of the constituents is developed. An energy concept is used for modelling fracture toughness. The energies dissipated in the four crack-paths (trans- and intergranular carbide fracture, fracture across the binder-ligaments, fracture in the binder close to the carbide/binder interface) are summed up using the experimentally determined area-fractions of the crack-paths, the specific energy of brittle fracture in the carbide and of ductile fracture is calculated by integrating the energy to deform a volume element over the plastically deformed region. In contrast to all earlier models, this concept describes fracture toughness of WC-Co alloys only with physically meaningful parameters. The excellent agreement with experimental toughness values and with qualitative observations of crack propagation show that the new model includes all effects which influence toughness. As demonstrated with WC-based hardmetals with a cobalt-nickel binder, the results open new possibilities for optimizing the toughness of composites in which a small amount of a tough phase is embedded in a brittle matrix. (Author, shortened by G.Q.)

  1. Shape distortion and dimensional precision in tungsten heavy alloy liquid phase sintering

    International Nuclear Information System (INIS)

    Wuwen Yi; German, R.M.; Lu, P.K.

    2001-01-01

    Microstructure effects on densification and shape distortion in liquid phase sintering of tungsten heavy alloy were investigated. Microstructure parameters such as the solid volume fraction, dihedral angle, initial porosity, and pore size were varied to measure densification and distortion behavior during LPS using W-Ni-Cu alloys. Green compacts were formed using ethylene-bis-stearamide as a pore-forming agent with the amount of polymer controlling the initial porosity. Different initial pore sizes were generated by varying the polymer particle size. Dihedral angle was varied by changing the Ni:Cu ratio in the alloys. Finally, the solid volume fraction was adjusted via the tungsten content. Distortion was quantified using profiles determined with a coordinate measuring machine to calculate a distortion parameter. Sintering results showed that solid volume fraction and dihedral angle are the dominant factors on densification and distortion during liquid phase sintering. Distortion decreases with increasing solid volume fraction and dihedral angle, while initial porosity and pore size have no observable effect on distortion at nearly full densification. Various strategies emerge to improve distortion control in liquid phase sintering. (author)

  2. Prevalence of exposure of heavy metals and their impact on health consequences.

    Science.gov (United States)

    Rehman, Kanwal; Fatima, Fiza; Waheed, Iqra; Akash, Muhammad Sajid Hamid

    2018-01-01

    Even in the current era of growing technology, the concentration of heavy metals present in drinking water is still not within the recommended limits as set by the regulatory authorities in different countries of the world. Drinking water contaminated with heavy metals namely; arsenic, cadmium, nickel, mercury, chromium, zinc, and lead is becoming a major health concern for public and health care professionals. Occupational exposure to heavy metals is known to occur by the utilization of these metals in various industrial processes and/or contents including color pigments and alloys. However, the predominant source resulting in measurable human exposure to heavy metals is the consumption of contaminated drinking water and the resulting health issues may include cardiovascular disorders, neuronal damage, renal injuries, and risk of cancer and diabetes. The general mechanism involved in heavy metal-induced toxicity is recognized to be the production of reactive oxygen species resulting oxidative damage and health related adverse effects. Thus utilization of heavy metal-contaminated water is resulting in high morbidity and mortality rates all over the world. Thereby, feeling the need to raise the concerns about contribution of different heavy metals in various health related issues, this article has discussed the global contamination of drinking water with heavy metals to assess the health hazards associated with consumption of heavy metal-contaminated water. A relationship between exposure limits and ultimate responses produced as well as the major organs affected have been reviewed. Acute and chronic poisoning symptoms and mechanisms responsible for such toxicities have also been discussed. © 2017 Wiley Periodicals, Inc.

  3. Biomolecules for Removal of Heavy Metal.

    Science.gov (United States)

    Singh, Namita Ashish

    2017-01-01

    Patents reveal that heavy metals are natural constituents of the earth's crust, but some heavy metals like cadmium, lead, mercury, arsenic etc. are injurious to living organisms at higher concentration. Nowadays, anthropogenic activities have altered geochemical cycles and biochemical balance of heavy metals. Biomolecules are used nowadays for removal of heavy metals compared to other synthetic biosorbents due to their environmental friendly nature and cost effectiveness. The goal of this work is to identify the role of biomolecules like polysaccharides, polypeptides, natural compounds containing aromatic acid etc. for heavy metal removal by bio sorption. It has been observed that efficiency of biomolecules can be increased by functionalization e.g. cellulose functionalization with EDTA, chitosan with sulphur groups, alginate with carboxyl/ hydroxyl group etc. It was found that the porous structure of aerogel beads improves both sorption and kinetic properties of the material. Out of polypeptides metallothionein has been widely used for removal of heavy metal up to 88% from seawater after a single centrifugation. These cost effective functionalized biomolecules are significantly used for remediation of heavy metals by immobilizing these biomolecules onto materials. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  4. Heavy metals in municipal solid waste deposits

    Energy Technology Data Exchange (ETDEWEB)

    Flyhammar, P.

    1997-12-01

    Extensive use of heavy metals in modern society influences routes followed by fluxes on the surface of the Earth. The changed flow paths may be harmful for the balance of biological systems at different levels, micro-organisms, human beings and whole ecosystems, since the toxicity of heavy metals is determined by their concentrations and chemical forms. Despite the low mobility of heavy metals (Zn, Cu, Pb, Cr, Ni and Cd) in municipal landfills, it was found that extensive transformations of the binding forms of heavy metal take place within the waste mass during the degradation of the waste. These changes appear to be closely related to the development of early diagenetic solid phases, i.e. new secondary solid phases formed in the waste. The heavy metals often constitute a minor part of these phases and the bindings include several forms such as adsorption, complexation, coprecipitation, precipitation, etc. It was also found that the associations between heavy metals and solid phases are dominated by several binding forms to one specific substrate rather than bindings to various solid phases. The mobility of iron and manganese seems to increase during the processes involved in waste degradation due to the solution of oxide/hydroxide phases, while the heavy metals appear to become less mobile due to their binding to organic compounds and sulphides. However, one exception in this case may be nickel. Another aspect of the transformation of heavy metals is the accumulation of pools of heavy metals which can become susceptible to environmental changes, such as oxidation or acidification. However, the risk of increased mobilization caused by lower pH values seem to be limited since municipal solid waste has a large buffer capacity. 66 refs, 9 figs, 3 tabs 66 refs, 9 figs, 3 tabs

  5. MICROBIAL REMOVAL OF HEAVY METALS FROM WASTEWATER

    Directory of Open Access Journals (Sweden)

    Justyna Koc-Jurczyk

    2014-10-01

    Full Text Available Industrialization and urbanization result in increase of heavy metals released into the environment (soil, lakes, rivers, seas, oceans, groundwater. Studies on biosorption of heavy metals are aimed to specify types of microorganisms which could efficiently bind metals. This approach has a very important significance for both slowing down metals exploitation by recovery, and also reduction of environmental pollution by decrease of their excessive concentration. Recent studies have reported about the capabilities of fungi, algae, yeasts, bacteria, waste and agricultural residues or materials containing chitosan derived from crustacean shells as a biosorbents. Biohydrometallurgy could be considered as a new “green” technology of heavy metals removal from wastewater.

  6. Possibility of clinical usefulness of heavy metal filter combinations in digital chest radiography

    International Nuclear Information System (INIS)

    Kawaji, Yasuyuki; Ideguchi, Tadamitsu; Ikeda, Hirotaka; Sakamoto, Hiromi; Higashida, Yoshiharu; Toyofuku, Fukai

    2003-01-01

    We have investigated the potential usefulness of the heavy metal filters with higher atomic numbers by comparing their patient exposures, tube loadings, radiographic contrasts, and the visual detection of simulated nodules in computed radiography (CR) with those of a combination of copper and aluminum. Seven heavy metal filters were used for this study. As for a tungsten filter, two filters different in thickness were used. One is 0.05 mm thick, and the other 0.10 mm. The other metal filters were respectively combined with a tungsten filter with a thickness of 0.05 mm. Among the all filters, tungsten with 0.1 mm thick and tungsten with 0.05 mm+barium which showed larger advantages in patient exposure and tube loading than those of the other filters were used for detection task of simulated nodules in chest radiography. The results indicated that the use of heavy metal filters can improve detectability of simulated nodules over that obtainable with conventional copper and aluminum filter. (author)

  7. Phytoremediation of heavy metals: Recent techniques | Jadia ...

    African Journals Online (AJOL)

    microorganisms/biomass or live plants to clean polluted areas. Phytoremediation is an emerging technology for cleaning up contaminated sites, which is ... A brief review on phytoremediation of heavy metals and its effect on plants have been ...

  8. Atmospheric Heavy Metal Pollution - Development of Chronological ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 4. Atmospheric Heavy Metal Pollution - Development of Chronological Records and Geochemical Monitoring. Rohit Shrivastav. General Article Volume 6 Issue 4 April 2001 pp 62-68 ...

  9. Spectrophotometric Determination Of Heavy Metals In Cosmetics

    African Journals Online (AJOL)

    ISSN 1597-6343. Spectrophotometric Determination Of Heavy Metals In Cosmetics ... analysed using atomic absorption spectrophotometer – coupled with a hydride ... presence of arsenic (As), mercury (Hg), cadmium (Cd) and lead. (Pb) in ...

  10. HEAVY METALS IN VINEYARDS AND ORCHARD SOILS

    Directory of Open Access Journals (Sweden)

    GUSTAVO BRUNETTO

    Full Text Available ABSTRACT The application of foliar fungicides in vineyards and orchards can increase soil concentration of heavy metals such as copper (Cu and zinc (Zn, up to the toxicity threshold for fruit trees and cover crops. However, some agronomic practices, such as liming, addition of organic fertilizers, cultivation of soil cover crops and inoculation of young plants with arbuscular mycorrhizal fungi can decrease the availability and the potential of heavy metal toxicity to fruit trees. This review aims to compile and present information about the effects of increasing concentrations of heavy metals, especially Cu and Zn, on soils cultivated with fruit trees and provides some agronomic practices of remediation. Information about the sources of heavy metals found in soils cultivated with fruit trees are presented; mechanisms of absorption, transport, accumulation and potential toxicity to plants are described.

  11. Heavy metals anthropogenic pollutants in Austria

    International Nuclear Information System (INIS)

    Anderl, M.; Gager, M.; Gugele, B.; Huttunen, K.; Kurzweil, A.; Poupa, S.; Ritter, M.; Wappel, D.; Wieser, M.

    2004-01-01

    Several heavy metals from anthropogenic sources are emitted in the atmosphere damaging the air quality and the human health, besides they accumulate on the soil and lately are transmitted into the human food chain. Therefore at international level there is a concern to reduce them. Austrian heavy metals emissions (cadmium, mercury and lead) during 1990-2002 are given including an analysis of causes and sources. Lead is the main pollutant and the main sector responsible is the industry. 5 figs. (nevyjel)

  12. Mobile heavy metal fractions in soils

    International Nuclear Information System (INIS)

    Horak, O.; Kamel, A.A.; Ecker, S.; Benetka, E.; Rebler, R.; Lummerstorfer, E.; Kandeler, E.

    1994-01-01

    A long term outdoor experiment was conducted in plastic containers (50 litres) with three soils, contaminated by increasing concentrations of zinc, copper, nickel, cadmium and vanadium. The aim of the study was to investigate the influence of heavy metal contamination on soil microbial processes as well as the accumulation of heavy metals in plants. Spring barley, followed by winter endive were grown as experimental crops in a first vegetation period, while spring wheat was grown during the second year. The soil microbial activities, indicated by arylsulfatase, dehydrogenase, and substrate-induced respiration, decreased with increasing heavy metal contamination. Significant correlations were observed between the inhibition of soil microorganisms and the easily mobilizable heavy metal fractions of soils, extracted by a solution of 1 M ammoniumacetate at pH = 7. The heavy metal accumulation in vegetative and generative parts of the crop plants also showed a good agreement with mobilizable soil fractions. The results of the experiment indicate, that the extraction with ammoniumacetate can be used as a reference method for determination of tolerable heavy metal concentrations in soils. (authors)

  13. Development and Testing of Dispersion-Strengthened Tungsten Alloys via Spark Plasma Sinterin

    Science.gov (United States)

    Lang, Eric; Madden, Nathan; Smith, Charles; Krogstad, Jessica; Allain, Jean Paul

    2017-10-01

    Tungsten (W) is a common plasma-facing component (PFC) material in the divertor region of tokamak fusion devices due to its high melting point and high sputter threshold. However, W is intrinsically brittle and is further embrittled under neutron irradiation, and the low recrystallization temperature pose complications in fusion environments. More ductile W alloys, such as dispersion-strengthened tungsten are being developed. In this work, W samples are processed via spark plasma sintering (SPS) with TiC, ZrC, and TaC dispersoids alloyed from 0.5 to 10 weight %. SPS is a powder compaction technique that provides high pressure and heating rates via electrical current, allowing for a lower final temperature and hold time for compaction. Initial testing of material properties, smicrostructure, and composition of specimens will be presented. Deuterium and helium irradiations have been performed in IGNIS, a multi-functional, in-situ irradiation and characterization facility at the University of Illinois. High-flux, low-energy exposures at the Magnum-PSI facility at DIFFER exposed samples to a D fluence of 1×1026 cm-2 and He fluence of 1x1025-1x1026 cm-2 at temperatures of 300-1000 C. In-situ chemistry changes via XPS and ex-situ morphology changes via SEM will be studied. Work supported by US DOE Contract DE-SC0014267.

  14. Mechanical properties of tungsten alloys with Y2O3 and titanium additions

    International Nuclear Information System (INIS)

    Aguirre, M.V.; Martin, A.; Pastor, J.Y.; LLorca, J.; Monge, M.A.; Pareja, R.

    2011-01-01

    In this research the mechanical behaviour of pure tungsten (W) and its alloys (2 wt.% Ti-0.47 wt.% Y 2 O 3 and 4 wt.% Ti-0.5 wt.% Y 2 O 3 ) is compared. These tungsten alloys, have been obtained by powder metallurgy. The yield strength, fracture toughness and elastic modulus have been studied in the temperature interval of 25 deg. C to 1000 deg. C. The results have shown that the addition of Ti substantially improves the bending strength and toughness of W, but it also dramatically increases the DBTT. On the other hand, the addition of 0.5% Y 2 O 3 , is enough to improve noticeably the oxidation behaviour at the higher temperatures. The grain size, fractography and microstructure are studied in these materials. Titanium is a good grain growth inhibitor and effective precursor of liquid phase in HIP. The simultaneous presence of Y 2 O 3 and Ti permits to obtain materials with low pores presence.

  15. Stabilizing the strengthening precipitates in aluminum-manganese alloys by the addition of tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yangyang; Makhlouf, Makhlouf M., E-mail: mmm@wpi.edu

    2017-04-13

    The Al-Mn-W system has considerable potential as a basis for lightweight aluminum alloys that are intended for use at temperatures approaching 350 °C (623 K). In this ternary system, aluminum, manganese, and tungsten co-precipitate to form the meta-stable Al{sub 12}(Mn{sub (1-x)}W{sub x}) phase, which is thermally stable and will not coarsen when held at elevated temperatures for extended periods of time. This enhanced thermal stability of the Al{sub 12}(Mn{sub (1-x)}W{sub x}) phase in comparison to the Al{sub 12}Mn phase which forms in binary Al-Mn alloys is explained in terms of the Gibbs free energy of the two phases. It is shown that co-precipitating tungsten with aluminum and manganese lowers the Gibbs free energy of the precipitated phase and by so doing, it slows down its coarsening rate and enhances its thermal stability.

  16. Gender identity and the electric guitar in heavy metal music

    OpenAIRE

    Kelly, Philip

    2009-01-01

    In this chapter I will attempt to outline the gendered characteristics of heavy metal and the electric guitar and address the question: has society’s impression of heavy metal as a primarily masculine pursuit been so imbedded in Western culture that we will never see a female heavy metal band achieve the same level of success as a male heavy metal band?

  17. Morphological Transition in the Cellular Structure of Single Crystals of Nickel-Tungsten Alloys near the Congruent Melting Point

    International Nuclear Information System (INIS)

    Azhazha, V.M.; Ladygin, A.N.; Sverdlov, V.Ja.; Zhemanyuk, P.D.; Klochikhin, V.V.

    2005-01-01

    The structure and microhardness of single crystals of nickel-tungsten alloys containing 25-36 wt % W are investigated. The temperature gradient at the crystallization front and the velocity of the crystallization front are the variable parameters of directional crystallization. It is found that, when the velocity of the crystallization front is 4 mm/min, the morphology of the cellular structure of the single crystals grown from nickel-tungsten alloys changes from square cells to hexagonal cells at a tungsten content of greater than or equal to 31 wt %. As the velocity of the crystallization front increases to 10 mm/min, no morphological transition occurs. It is shown that impurities play an important role in the formation of a cellular structure with cells of different types

  18. Heavy Metal Poisoning and Cardiovascular Disease

    Directory of Open Access Journals (Sweden)

    Eman M. Alissa

    2011-01-01

    Full Text Available Cardiovascular disease (CVD is an increasing world health problem. Traditional risk factors fail to account for all deaths from CVD. It is mainly the environmental, dietary and lifestyle behavioral factors that are the control keys in the progress of this disease. The potential association between chronic heavy metal exposure, like arsenic, lead, cadmium, mercury, and CVD has been less well defined. The mechanism through which heavy metals act to increase cardiovascular risk factors may act still remains unknown, although impaired antioxidants metabolism and oxidative stress may play a role. However, the exact mechanism of CVD induced by heavy metals deserves further investigation either through animal experiments or through molecular and cellular studies. Furthermore, large-scale prospective studies with follow up on general populations using appropriate biomarkers and cardiovascular endpoints might be recommended to identify the factors that predispose to heavy metals toxicity in CVD. In this review, we will give a brief summary of heavy metals homeostasis, followed by a description of the available evidence for their link with CVD and the proposed mechanisms of action by which their toxic effects might be explained. Finally, suspected interactions between genetic, nutritional and environmental factors are discussed.

  19. [Resistance to heavy metals in ruminal staphylococci].

    Science.gov (United States)

    Lauková, A

    1994-01-01

    Ruminal, coagulase-negative, urease and bacteriocin-like substances producing staphylococci were screened for their heavy metal ions and antibiotics resistance. All strains tested were resistant to disodium arsenate at a minimal inhibition concentration (MIC > 5 g/l) and cadmium sulphate (MIC > 4 g/l). MIC = 50-60 mg/l was determined in eight staphylococci screened in mercury chloride resistance test (Tab. I). Silver nitrate resistance was detected in seven of the bacteria used (MIC = 40-50 mg/l). All strains were novobiocin resistant. Staphylococcus cohnii subsp. urealyticum SCU 40 was found as a strain with resistance to all heavy metal ions and 5 antibiotics (Tab. II). In addition, this strain produced bacteriocin-like substance which inhibited growth of six indicators of different origin (Tab. II). The most of staphylococci were detected as heavy metal ion polyresistant strains and antibiotic polyresistant strains producing antimicrobial substances with inhibition effects against at least one indicator of different origin. These results represent the first information on heavy metal ion resistance in ruminal bacteria. They also show relation or coresistance between heavy metal ions and antibiotics. Resulting from this study, staphylococci can be used as a bioindicator model for animal environmental studies. In addition, it can be used for specific interactions studies within the framework of ruminal bacterial ecosystem and also mainly with regard to molecular genetic studies.

  20. Synthesis of electric discharge alloyed nickel–tungsten coating on tool steel and its tribological studies

    International Nuclear Information System (INIS)

    Arun, Ilangovan; Duraiselvam, Muthukannan; Senthilkumar, V.; Narayanasamy, R.; Anandakrishnan, V.

    2014-01-01

    Highlights: • Electrical discharge alloying/coating made on AISI D2 tool steel. • The hardness of EDA layer is three to four time higher than the base material. • The dry sliding wear tests performed on EDA layer at different temperatures. • The alloyed layer acts as a self-lubricant at higher temperature. - Abstract: The present study examines the method of depositing nickel and tungsten on die steel surface by means of dispersing these elements in dielectric fluid in an electrical discharge alloying (EDA) process. The modified surface was mechanically and metallurgically characterized using Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), microhardness tester and Pin-on-disc tribometer. The phase transformations that occurred during EDA process were evaluated by XRD. The deposition of Ni and W on die steel surfaces yielded minimal cracks with excellent metallurgical bonding. Higher hardness (∼1059 HV 0.3 ) with little brittleness resulted in superior wear resistance properties, a property which was retained even at elevated temperature

  1. Advantages of heavy metal collars in directional drilling and deviation control

    International Nuclear Information System (INIS)

    Bradley, W.B.; Murphey, C.E.; McLamore, R.T.; Dickson, L.L.

    1976-01-01

    A heavy, stiff-bottom drill collar can substantially improve deviation performance, theoretically increasing penetration rates by 50 to 100 percent in deviation-prone areas. This paper presents the underlying theory, practical charts on performance characteristics, and Shell Development Co.'s experience in fabricating and field testing two depleted-uranium alloy, heavy metal collars

  2. Room and ultrahigh temperature structure-mechanical property relationships of tungsten alloys formed by field assisted sintering technique (FAST)

    Energy Technology Data Exchange (ETDEWEB)

    Browning, Paul N.; Alagic, Sven [Pennsylvania State University, Department of Materials Science and Engineering, State College, PA-16801 (United States); Pennsylvania State University, Applied Research Laboratory, State College, PA-16801 (United States); Kulkarni, Anil [Pennsylvania State University, Department of Nuclear and Mechanical Engineering, State College, PA-16801 (United States); Matson, Lawrence [Materials and Manufacturing Directorate, Wright Patterson Air Force Base, Dayton, OH (United States); Singh, Jogender, E-mail: jxs46@arl.psu.edu [Pennsylvania State University, Department of Materials Science and Engineering, State College, PA-16801 (United States); Pennsylvania State University, Applied Research Laboratory, State College, PA-16801 (United States)

    2016-09-30

    Tungsten based alloys have become of critical importance in a number of applications including plasma-facing materials in nuclear fusion reactors, rocket nozzles for aerospace applications, and in kinetic energy penetrators in the defense industry. Formation of components for these uses by powder metallurgical techniques has proven challenging, due to tungsten's relatively poor sinterability. Here we report the use of field assisted sintering technique (FAST) to produce high density, fine grain alloys with mechanical properties comparable or superior to that of components produced by conventional techniques. Alloys of pure tungsten, W-3 vol%TiC, W-5 vol%TiC, and W-10 vol%Ta were synthesized at 2100 °C, 35 MPa for 25 min using FAST. Microstructural characterization revealed effective reduction of grain size with TiC addition and preferential diffusion of oxygen into the center of tantalum particles in tantalum containing alloys. Tensile testing of alloys revealed TiC addition to W resulted in substantially improved ultimate tensile strength at the cost of ductility in comparison at temperatures up to 1926 °C (3500 °F) however this strengthening effect was lost at 2204 °C (4000 °F). Addition of 10 vol%Ta to W resulted in reduced hardness at room temperature, but substantially increased yield strength at the cost of slightly reduced ductility at 1926 °C and 2204 °C.

  3. Heavy metal hazards of Nigerian herbal remedies

    Energy Technology Data Exchange (ETDEWEB)

    Obi, E. [Toxicology Unit, Department of Pharmacology, College of Health Sciences, Nnamdi Azikiwe University, Nnewi (Nigeria); Akunyili, Dora N. [National Agency of Food and Drug Administration and Control (NAFDAC), Lagos (Nigeria); Ekpo, B. [Department of Biochemistry, College of Medical Sciences, Abia State University, Uturu (Nigeria); Orisakwe, Orish E. [Toxicology Unit, Department of Pharmacology, College of Health Sciences, Nnamdi Azikiwe University, Nnewi (Nigeria)]. E-mail: eorish@yahoo.com

    2006-10-01

    The uses of herbal products are not regulated in Nigeria and in many low-income countries and are freely available to everyone. The safety of these herbal medicines is poorly understood. This study characterizes the content of cadmium, copper, iron, nickel, selenium, zinc, lead and mercury in a random sample of Nigerian traditional products. Ready-to-use herbal products were purchased from the open market and digested using HNO{sub 3}.The heavy metal content of the digested filtrate was determined by atomic absorption spectrometry Uni-cam Model 929. The result showed that 100% of the samples contained elevated amounts of heavy metals. These data alert us to the possibility of heavy metal toxicity from herbal products in Nigeria. The public health hazards from ingestion of herbal medicines should be identified and disclosed by in-depth risk assessment studies.

  4. Remediating sites contaminated with heavy metals

    International Nuclear Information System (INIS)

    Swartzbaugh, J.; Sturgill, J.; Cormier, B.; Williams, H.D.

    1992-01-01

    This article is intended to serve as a reference for decision makers who must choose an approach to remediate sites contaminated with heavy metals. Its purpose is to explain pertinent chemical and physical characteristics of heavy metals, how to use these characteristics to select remedial technologies, and how to interpret and use data from field investigations. Different metal species are typically associated with different industrial processes. The contaminant species behave differently in various media (i.e., groundwater, soils, air), and require different technologies for containment and treatment. We focus on the metals that are used in industries that generate regulated waste. These include steelmaking, paint and pigment manufacturing, metal finishing, leather tanning, papermaking, aluminum anodizing, and battery manufacturing. Heavy metals are also present in refinery wastes as well as in smelting wastes and drilling muds

  5. Heavy metal hazards of Nigerian herbal remedies

    International Nuclear Information System (INIS)

    Obi, E.; Akunyili, Dora N.; Ekpo, B.; Orisakwe, Orish E.

    2006-01-01

    The uses of herbal products are not regulated in Nigeria and in many low-income countries and are freely available to everyone. The safety of these herbal medicines is poorly understood. This study characterizes the content of cadmium, copper, iron, nickel, selenium, zinc, lead and mercury in a random sample of Nigerian traditional products. Ready-to-use herbal products were purchased from the open market and digested using HNO 3 .The heavy metal content of the digested filtrate was determined by atomic absorption spectrometry Uni-cam Model 929. The result showed that 100% of the samples contained elevated amounts of heavy metals. These data alert us to the possibility of heavy metal toxicity from herbal products in Nigeria. The public health hazards from ingestion of herbal medicines should be identified and disclosed by in-depth risk assessment studies

  6. Heavy metal pollution of agricultural soils

    Energy Technology Data Exchange (ETDEWEB)

    Jarvis, S.C.

    1975-01-01

    Inputs of heavy metals to soils have increased recently and there is much concern that they may be toxic at various stages along the food chain and ultimately to man. Cobalt, copper, iron, manganese, molybdenum, zinc, chromium, nickel, cadmium and lead move from geochemical sources to plants and then to animals and man; they then are returned in various forms to soil to complete the cycle. The ways in which heavy metals may be added to soils are reviewed. They include: aerial inputs by air pollution, fertilizers, pesticides, farm slurries and sewage sludge. Possibly the source of contamination which is to have the most impact on soils used for the production of crops is sewage sludge. The fate of heavy metal added to soils is discussed in relation to form, mobility, uptake by plants, effect of soil conditions on availability to plants, and toxicity to animals. 56 references.

  7. Structural, magnetic, and mechanical properties of electrodeposited cobalt–tungsten alloys: Intrinsic and extrinsic interdependencies

    International Nuclear Information System (INIS)

    Tsyntsaru, N.; Cesiulis, H.; Pellicer, E.; Celis, J.-P.; Sort, J.

    2013-01-01

    The mapping of structural, magnetic, and mechanical properties of Co–W coatings galvanostatically electrodeposited from a citrate–borate bath is investigated. The intrinsic characteristics of the coatings, such as crystallite size or tungsten content are correlated with the extrinsic growth parameters, such as pH, complexes distribution, and current density. The increase in pH from 5 to 8 results in an increase of the W content in the deposits from 2 at.% up to 36 at.% in a controlled way, and it correlates with an increase in concentration of W(VI) complexes in the bath. The crystallite size estimated from XRD patterns, decreases from 39 to 5 nm with increasing W content from 3 to 25 at.% respectively. The obtained coatings show highly tunable mechanical and magnetic properties. The hardness increases with W content from ∼3 GPa up to ∼13 GPa. A semi-hard ferromagnetic behavior with a coercivity of ∼470 Oe along the perpendicular-to-plane direction is observed for Co–W alloys containing small amounts of W in the range of ∼2–3 at.%. At higher tungsten contents the coatings are magnetically softer, and the electrodeposits become non-ferromagnetic beyond ∼30 at.% W. Because of this combination of physical properties, electrodeposited Co–W coatings may become suitable materials for multi-scale technologies

  8. Mechanical alloying and sintering of nanostructured tungsten carbide-reinforced copper composite and its characterization

    International Nuclear Information System (INIS)

    Yusoff, Mahani; Othman, Radzali; Hussain, Zuhailawati

    2011-01-01

    Research highlights: → W 2 C phase was formed at short milling time while WC only appears after longer milling time. → Cu crystallite size decreased but internal strain increased with increasing milling time. → Increasing milling time induced more WC formation, thus improving the hardness of the composite. → Electrical conductivity is reduced due to powder refinement and the presence of carbide phases. -- Abstract: Elemental powders of copper (Cu), tungsten (W) and graphite (C) were mechanically alloyed in a planetary ball mill with different milling durations (0-60 h), compacted and sintered in order to precipitate hard tungsten carbide particles into a copper matrix. Both powder and sintered composite were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and assessed for hardness and electrical conductivity to investigate the effects of milling time on formation of nanostructured Cu-WC composite and its properties. No carbide peak was detected in the powder mixtures after milling. Carbide WC and W 2 C phases were precipitated only in the sintered composite. The formation of WC began with longer milling times, after W 2 C formation. Prolonged milling time decreased the crystallite size as well as the internal strain of Cu. Hardness of the composite was enhanced but electrical conductivity reduced with increasing milling time.

  9. Heavy Metal Pollution Around International Hatay Airport

    Directory of Open Access Journals (Sweden)

    Abdullah Özkan

    2017-02-01

    Full Text Available In this study, it was aimed to determine the heavy metal pollution in the agricultural lands around Hatay airport and travel possible alteration in the amount of heavy metal on the land in accordance with the distance to the airport. For this purpose, the airport was chosen as the center and 27 soil samples were obtained around the airport at 2 km intervals in depth ranging from 0 to 30 cm. Lead (Pb, cadmium (Cd, nickel (Ni, chrome (Cr, cobalt (Co, aluminium (Al, iron (Fe, copper (Cu, manganese (Mn and zinc (Zn elements in soil samples were analysed using MP-AES instrument by DTPA method. (3 repetition for each sample. As a result of the analysis, heavy metal concentrations were found as Pb 0-1.45 mg/kg, Cd 0-0.220 mg/kg, Ni 0-3.95 mg/kg, Cr 0-0.780 mg/kg, Co 0-0.270 mg/kg, Al 0-0.700 mg/kg, Fe 1.47- 16.2 mg/kg, Cu 0.400-5.35 mg/kg, Mn 0-19 mg/kg and Zn 0.050-3.14 mg/kg. When comparing the obtained data through this study with allowable concentrations of heavy metals in soil of Environment and Forest Directorates Guidance, it was determined that the heavy metal concentration of the soil does not pose any problems in terms of heavy metal pollution. Besides, iron concentration was decreased when the distance to the airport is increased.

  10. A process for electrodeposition of layers of niobium, vanadium, molybdenum or tungsten, or of their alloys

    International Nuclear Information System (INIS)

    Diepers, H.; Schmidt, O.

    1977-01-01

    An improvement is proposed for the process for electrodeposition of layers of niobium, vanadium, molybdenum or tungsten or of their alloys from molten-salt electrolytes (fluorid melts) which is to increase the quality of layers in order to obtain regular thickness and smooth surfaces. According to the invention, a pre-separation is executed on an auxiliary cathode before the (preheated) cathode is immersed. The cathode is only charged for separation after the adjustment of a constant anode potential. It is an advantage that the auxiliary cathode is mechanically and electrically connected with the cathode. As an electrolyte, a mixture of niobium fluorides and a eustetic mixture of potassium fluorides, sodium fluorides and lithium fluorides are particularly suitable for the electrodeposition of miobium. (UWI) [de

  11. Optimisation and characterisation of tungsten thick coatings on copper based alloy substrates

    Science.gov (United States)

    Riccardi, B.; Montanari, R.; Casadei, M.; Costanza, G.; Filacchioni, G.; Moriani, A.

    2006-06-01

    Tungsten is a promising armour material for plasma facing components of nuclear fusion reactors because of its low sputter rate and favourable thermo-mechanical properties. Among all the techniques able to realise W armours, plasma spray looks particularly attractive owing to its simplicity and low cost. The present work concerns the optimisation of spraying parameters aimed at 4-5 mm thick W coating on copper-chromium-zirconium (Cu,Cr,Zr) alloy substrates. Characterisation of coatings was performed in order to assess microstructure, impurity content, density, tensile strength, adhesion strength, thermal conductivity and thermal expansion coefficient. The work performed has demonstrated the feasibility of thick W coatings on flat and curved geometries. These coatings appear as a reliable armour for medium heat flux plasma facing component.

  12. Optimisation and characterisation of tungsten thick coatings on copper based alloy substrates

    International Nuclear Information System (INIS)

    Riccardi, B.; Montanari, R.; Casadei, M.; Costanza, G.; Filacchioni, G.; Moriani, A.

    2006-01-01

    Tungsten is a promising armour material for plasma facing components of nuclear fusion reactors because of its low sputter rate and favourable thermo-mechanical properties. Among all the techniques able to realise W armours, plasma spray looks particularly attractive owing to its simplicity and low cost. The present work concerns the optimisation of spraying parameters aimed at 4-5 mm thick W coating on copper-chromium-zirconium (Cu,Cr,Zr) alloy substrates. Characterisation of coatings was performed in order to assess microstructure, impurity content, density, tensile strength, adhesion strength, thermal conductivity and thermal expansion coefficient. The work performed has demonstrated the feasibility of thick W coatings on flat and curved geometries. These coatings appear as a reliable armour for medium heat flux plasma facing component

  13. Optimisation and characterisation of tungsten thick coatings on copper based alloy substrates

    Energy Technology Data Exchange (ETDEWEB)

    Riccardi, B. [Associazione Euratom-ENEA sulla Fusione, CR Frascati, P.B. 65 00044 Frascati, Roma (Italy)]. E-mail: riccardi@frascati.enea.it; Montanari, R. [Dipartimento di Ingegneria Meccanica, Universita di Roma, Tor Vergata, 00133 Roma (Italy); Casadei, M. [Centro Sviluppo Materiali, 00100 Roma (Italy); Costanza, G. [Dipartimento di Ingegneria Meccanica, Universita di Roma, Tor Vergata, 00133 Roma (Italy); Filacchioni, G. [ENEA CR Casaccia, I-00060 S. M. di Galeria, Roma (Italy); Moriani, A. [Associazione Euratom-ENEA sulla Fusione, CR Frascati, P.B. 65 00044 Frascati, Roma (Italy)

    2006-06-30

    Tungsten is a promising armour material for plasma facing components of nuclear fusion reactors because of its low sputter rate and favourable thermo-mechanical properties. Among all the techniques able to realise W armours, plasma spray looks particularly attractive owing to its simplicity and low cost. The present work concerns the optimisation of spraying parameters aimed at 4-5 mm thick W coating on copper-chromium-zirconium (Cu,Cr,Zr) alloy substrates. Characterisation of coatings was performed in order to assess microstructure, impurity content, density, tensile strength, adhesion strength, thermal conductivity and thermal expansion coefficient. The work performed has demonstrated the feasibility of thick W coatings on flat and curved geometries. These coatings appear as a reliable armour for medium heat flux plasma facing component.

  14. Ricochet of a tungsten heavy alloy long-rod projectile from deformable steel plates

    International Nuclear Information System (INIS)

    Lee, Woong; Lee, Heon-Joo; Shin, Hyunho

    2002-01-01

    Ricochet of a tungsten heavy alloy long-rod projectile from oblique steel plates with a finite thickness was investigated numerically using a full three-dimensional explicit finite element method. Three distinctive regimes resulting from oblique impact depending on the obliquity, namely simple ricochet, critical ricochet and target perforation, were investigated in detail. Critical ricochet angles were calculated for various impact velocities and strengths of the target plates. It was predicted that critical ricochet angle increases with decreasing impact velocities and that higher ricochet angles were expected if higher strength target materials are employed. Numerical predictions were compared with existing two-dimensional analytical models. Experiments were also carried out and the results supported the predictions of the numerical analysis

  15. Mushrooms pollution by radioactivity and heavy metals

    International Nuclear Information System (INIS)

    Delatouche, L.

    2001-01-01

    Some basic notions of radioactivity are recalled first (definition, origin, measurement units, long- and short-term effects..). Then, the pedology of soils and the properties and toxicity of 3 heavy metals (lead, cadmium, mercury) are presented to better understand the influence of some factors (genre, age, ecological type, pollution, conservation..) on the contamination of macro-mycetes by radioactivity and heavy metals. The role of chemists is to inform the consumers about these chemical and radioactive pollutions and to give some advices about the picking up (quantities, species and places to avoid) and the cooking of mushrooms. (J.S.)

  16. Heavy metals in MSW incineration fly ashes

    DEFF Research Database (Denmark)

    Ferreira, Celia; Ribeiro, Alexandra B.; Ottosen, Lisbeth M.

    2003-01-01

    Incineration is a common solution for dealing with the increasing amount of municipal solid waste (MSW). During the process, the heavy metals initially present in the waste go through several transformations, ending up in combustion products, such as fly ash. This article deals with some issues...... related to the combustion of MSW and the formation of fly ash, especially in what concerns heavy metals. Treatment of the flue gas in air pollution control equipment plays an important role and the basic processes to accomplish this are explained. Fly ash from a semi-dry flue gas treatment system...

  17. Mechanism and Microstructure of Oxide Fluxes for Gas Tungsten Arc Welding of Magnesium Alloy

    Science.gov (United States)

    Liu, L. M.; Zhang, Z. D.; Song, G.; Wang, L.

    2007-03-01

    Five single oxide fluxes—MgO, CaO, TiO2, MnO2, and Cr2O3—were used to investigate the effect of active flux on the depth/width ratio in AZ31B magnesium alloy. The microstructure and mechanical property of the tungsten inert gas (TIG) welding seam were studied. The oxygen content in the weld seam and the arc images during the TIG welding process were analyzed. A series of emission spectroscopy of weld arc for TIG welding for magnesium with and without flux were developed. The results showed that for the five single oxide fluxes, all can increase the weld penetration effectively and grain size in the weld seam of alternating current tungsten inert gas (ACTIG) welding of the Mg alloy. The oxygen content of the welds made without flux is not very different from those produced with oxide fluxes not considering trapped oxide. However, welds that have the best penetration have a relatively higher oxygen content among those produced with flux. It was found that the arc images with the oxide fluxes were only the enlarged form of the arc images without flux; the arc constriction was not observed. The detection of arc spectroscopy showed that the metal elements in the oxides exist as the neutral atom or the first cation in the weld arc. This finding would influence the arc properties. When TIG simulation was carried out on a plate with flux applied only on one side, the arc image video showed an asymmetric arc, which deviated toward the flux free side. The thermal stability, the dissociation energy, and the electrical conductivity of oxide should be considered when studying the mechanism for increased TIG flux weld penetration.

  18. Multiscale Modeling of Grain Boundary Segregation and Embrittlement in Tungsten for Mechanistic Design of Alloys for Coal Fired Plants

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Jian; Tomar, Vikas; Zhou, Naixie; Lee, Hongsuk

    2013-06-30

    Based on a recent discovery of premelting-like grain boundary segregation in refractory metals occurring at high temperatures and/or high alloying levels, this project investigated grain boundary segregation and embrittlement in tungsten (W) based alloys. Specifically, new interfacial thermodynamic models have been developed and quantified to predict high-temperature grain boundary segregation in the W-Ni binary alloy and W-Ni-Fe, W-Ni-Ti, W-Ni-Co, W-Ni-Cr, W-Ni-Zr and W-Ni-Nb ternary alloys. The thermodynamic modeling results have been experimentally validated for selected systems. Furthermore, multiscale modeling has been conducted at continuum, atomistic and quantum-mechanical levels to link grain boundary segregation with embrittlement. In summary, this 3-year project has successfully developed a theoretical framework in combination with a multiscale modeling strategy for predicting grain boundary segregation and embrittlement in W based alloys.

  19. Hydroponics reducing effluent's heavy metals discharge.

    Science.gov (United States)

    Rababah, Abdellah; Al-Shuha, Ahmad

    2009-01-01

    This paper investigates the capacity of Nutrient Film Technique (NFT) to control effluent's heavy metals discharge. A commercial hydroponic system was adapted to irrigate lettuces with primary treated wastewater for studying the potential heavy metals removal. A second commercial hydroponic system was used to irrigate the same type of lettuces with nutrient solution and this system was used as a control. Results showed that lettuces grew well when irrigated with primary treated effluent in the commercial hydroponic system. The NFT-plant system heavy metals removal efficiency varied amongst the different elements, The system's removal efficiency for Cr was more than 92%, Ni more than 85%, in addition to more than 60% reduction of B, Pb, and Zn. Nonetheless, the NFT-plants system removal efficiencies for As, Cd and Cu were lower than 30%. Results show that lettuces accumulated heavy metals in leaves at concentrations higher than the maximum acceptable European and Australian levels. Therefore, non-edible plants such as flowers or pyrethrum are recommended as value added crops for the proposed NFT.

  20. Heavy metal removal and recovery using microorganisms

    International Nuclear Information System (INIS)

    Wilde, E.W.; Benemann, J.R.

    1991-02-01

    Microorganisms -- bacteria, fungi, and microalgae -- can accumulate relatively large amounts of toxic heavy metals and radionuclides from the environment. These organisms often exhibit specificity for particular metals. The metal content of microbial biomass can be a substantial fraction of total dry weight with concentration factors (metal in dry biomass to metal in solution) exceeding one million in some cases. Both living and inert (dead) microbial biomass can be used to reduce heavy metal concentrations in contaminated waters to very low levels -- parts per billion and even lower. In many respects (e.g. specificity, residual metal concentrations, accumulation factors, and economics) microbial bioremoval processes can be superior to conventional processes, such as ion exchange and caustic (lime or hydroxide) precipitation for heavy metals removal from waste and contaminated waters. Thus, bioremoval could be developed to contribute to the clean-up of wastes at the Savannah River Site (SRS) and other DOE facilities. However, the potential advantages of bioremoval processes must still be developed into practical operating systems. A detailed review of the literature suggests that appropriate bioremoval processes could be developed for the SRS. There is great variability from one biomass source to another in bioremoval capabilities. Bioremoval is affected by pH, other ions, temperature, and many other factors. The biological (living vs. dead) and physical (immobilized vs. dispersed) characteristics of the biomass also greatly affect metal binding. Even subtle differences in the microbial biomass, such as the conditions under which it was cultivated, can have major effects on heavy metal binding

  1. Evaluation of Physicochemical Properties and Heavy Metals ...

    African Journals Online (AJOL)

    Physicochemical properties of municipal dumpsite compost in Kano metropolis and concentration of heavy metals were investigated. Analysis was carried out by atomic absorption spectrometry (Buck Scientific VPG 210). The results shows that the compost pH (6.63-8.19), electric conductivity of compost (638-933μs/cm), ...

  2. Heavy metal contamination in TIMS Branch sediments

    International Nuclear Information System (INIS)

    Pickett, J.B.

    1990-01-01

    The objective of this memorandum is to summarize results of previous sediment studies on Tims Branch and Steed's Pond conducted by Health Protection (HP) and by the Savannah River Laboratory (SRL) in conjunction with Reactor Materials Engineering ampersand Technology (RMET). The results for other heavy metals, such as lead, nickel, copper, mercury, chromium, cadmium, zinc, and thorium are also summarized

  3. Heavy metal removal and recovery using microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, E.W. (Westinghouse Savannah River Co., Aiken, SC (United States)); Benemann, J.R. (Benemann (J.R.), Pinole, CA (United States))

    1991-02-01

    Microorganisms -- bacteria, fungi, and microalgae -- can accumulate relatively large amounts of toxic heavy metals and radionuclides from the environment. These organisms often exhibit specificity for particular metals. The metal content of microbial biomass can be a substantial fraction of total dry weight with concentration factors (metal in dry biomass to metal in solution) exceeding one million in some cases. Both living and inert (dead) microbial biomass can be used to reduce heavy metal concentrations in contaminated waters to very low levels -- parts per billion and even lower. In many respects (e.g. specificity, residual metal concentrations, accumulation factors, and economics) microbial bioremoval processes can be superior to conventional processes, such as ion exchange and caustic (lime or hydroxide) precipitation for heavy metals removal from waste and contaminated waters. Thus, bioremoval could be developed to contribute to the clean-up of wastes at the Savannah River Site (SRS) and other DOE facilities. However, the potential advantages of bioremoval processes must still be developed into practical operating systems. A detailed review of the literature suggests that appropriate bioremoval processes could be developed for the SRS. There is great variability from one biomass source to another in bioremoval capabilities. Bioremoval is affected by pH, other ions, temperature, and many other factors. The biological (living vs. dead) and physical (immobilized vs. dispersed) characteristics of the biomass also greatly affect metal binding. Even subtle differences in the microbial biomass, such as the conditions under which it was cultivated, can have major effects on heavy metal binding.

  4. Heavy metal bioaccumulation in Callinectes amnicola and ...

    African Journals Online (AJOL)

    The bioaccumulation of heavy metals in organisms is as a result of pollutants discharge generated by anthropogenic and natural activities which has become a tremendous concern in developing nations. The levels of cadmium, copper, chromium, lead, zinc and nickel in the tissue of Callinectes amnicola and ...

  5. Heavy metals: teeth as environmental biomarkers

    OpenAIRE

    Lumbau, Aurea Maria Immacolata; Lugliè, Pietrina Francesca; Carboni, Donatella; Ginesu, Sergio; Falchi, Simonetta; Schinocca, Laura

    2012-01-01

    Aim of this study was to measure the concentration of heavy metals in tooth matrix and to determine the factors that affect their presence. During tooth development and mineralization several metals can be absorbed in the tooth matrix, thus allowing us to use them as biological markers.

  6. Heavy metals contamination of Chrysichthys nigrodigitatus and ...

    African Journals Online (AJOL)

    This study investigates the presence of heavy metal contamination of Chrysichthys nigrodigitatus and Lates niloticus. Adult C. nigrodigitatus and L. niloticus were obtained from fishermen in Ikere Gorge, Oyo state, Nigeria. Water samples were also collected during the wet and dry seasons of the year in the same locality.

  7. Heavy metal levels, physicochemical properties and microbial ...

    African Journals Online (AJOL)

    Journal of Applied Sciences and Environmental Management ... out to assess the microbial, physicochemical and heavy metal characteristics of soil samples from five different waste collection sites within the University of Benin, Benin City and evaluated using standard analytical and classical microbiological methods.

  8. Photoelectrochemical detection of toxic heavy metals

    CSIR Research Space (South Africa)

    Chamier, J

    2010-09-01

    Full Text Available on various substrates introduced the possibility for portable and on-site instant verification of heavy metal pollutants. In this work, the favorable properties of the mercury-sensitive fluorescent molecule, Rhodamine 6G hydrozone derivative (RS), were...

  9. Electrodialytic decontamination of heavy metal polluted soil

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Hansen, Henrik K.; Karlsmose, Bodil

    1996-01-01

    Electrodialytic remediation of heavy metal polluted soil is a newly developed method, which combines the electrokinetic mevement of ions in soil with the principle of electrodialytis. The method has been proven to work in laboratory scale and at present two types of pilot plant tests are made....

  10. Esterase resistant to inactivation by heavy metals

    KAUST Repository

    El, Dorry Hamza; Siam, Rania; Mohamed, Yasmine M.

    2014-01-01

    EstATII is an esterase that a halotolerant, thermophilic and resistant to a spectrum of heavy metals including toxic concentration of metals. It was isolated from the lowest convective layer of the Atlantis II Red Sea brine pool. The Atlantis II

  11. HEAVY METALS CONTAMINATION OF TOPSOIL AND ...

    African Journals Online (AJOL)

    a

    emissions from automobile exhaust, waste incineration, land disposal of wastes, use of .... of total organic carbon increased from 2.0 ± 1.5 % in the top soil to 3.42 ± 0.83 ..... Thus, accumulation of heavy metals in the soil has potential to restrict.

  12. Laser cladding of tungsten carbides (Spherotene) hardfacing alloys for the mining and mineral industry

    International Nuclear Information System (INIS)

    Amado, J.M.; Tobar, M.J.; Alvarez, J.C.; Lamas, J.; Yanez, A.

    2009-01-01

    The abrasive nature of the mechanical processes involved in mining and mineral industry often causes significant wear to the associated equipment and derives non-negligible economic costs. One of the possible strategies to improve the wear resistance of the various components is the deposition of hardfacing layers on the bulk parts. The use of high power lasers for hardfacing (laser cladding) has attracted a great attention in the last decade as an alternative to other more standard methods (arc welding, oxy-fuel gas welding, thermal spraying). In laser cladding the hardfacing material is used in powder form. For high hardness applications Ni-, Co- or Fe-based alloys containing hard phase carbides at different ratios are commonly used. Tungsten carbides (WC) can provide coating hardness well above 1000 HV (Vickers). In this respect, commercially available WC powders normally contain spherical micro-particles consisting of crushed WC agglomerates. Some years ago, Spherotene powders consisting of spherical-fused monocrystaline WC particles, being extremely hard, between 1800 and 3000 HV, were patented. Very recently, mixtures of Ni-based alloy with Spherotene powders optimized for laser processing were presented (Technolase). These mixtures have been used in our study. Laser cladding tests with these powders were performed on low carbon steel (C25) substrates, and results in terms of microstructure and hardness will be discussed

  13. Creep laws for refractory tungsten alloys between 900 and 1100 oC under low stress

    International Nuclear Information System (INIS)

    Gallet, D.; Dhers, J.; Levoy, R.; Polcik, P.

    2001-01-01

    Refractory metals and alloys with melting point above 2500 o C, are commonly used at temperature well above 1000 o C. Very few creep data exist at low temperature and low stress. In the present work, we studied the micro-creep deformation and the structure stability of different W and W alloys, W-B, W-La 2 O 3 , W-K, W-Re, in the temperature range 900-1100 o C and stress range 10-50 MPa, up to 500 hours. A Norton type law has been established for those materials. Stress exponents around 1.0 have been obtained. Activation energies have been determined, and are much lower than self diffusion energies for all materials tested. The main mechanism involved has been identified as Harper-Dorn creep, implying some dislocation rearrangement. The dopants are classified according to their efficiency in creep reduction and boron at 100 ppm has been found to be the most efficient, whereas at 10 ppm, it degrades the behavior of stress relieved tungsten. Furthermore, we have found that the addition of some elements may have an efficient effect as recrystallization inhibitor. (author)

  14. Laser cladding of tungsten carbides (Spherotene) hardfacing alloys for the mining and mineral industry

    Energy Technology Data Exchange (ETDEWEB)

    Amado, J.M. [Departamento de Ingenieria Industrial II, Universidade da Coruna, Mendizabal s/n, Ferrol E-15403 (Spain); Tobar, M.J. [Departamento de Ingenieria Industrial II, Universidade da Coruna, Mendizabal s/n, Ferrol E-15403 (Spain)], E-mail: cote@udc.es; Alvarez, J.C.; Lamas, J.; Yanez, A. [Departamento de Ingenieria Industrial II, Universidade da Coruna, Mendizabal s/n, Ferrol E-15403 (Spain)

    2009-03-01

    The abrasive nature of the mechanical processes involved in mining and mineral industry often causes significant wear to the associated equipment and derives non-negligible economic costs. One of the possible strategies to improve the wear resistance of the various components is the deposition of hardfacing layers on the bulk parts. The use of high power lasers for hardfacing (laser cladding) has attracted a great attention in the last decade as an alternative to other more standard methods (arc welding, oxy-fuel gas welding, thermal spraying). In laser cladding the hardfacing material is used in powder form. For high hardness applications Ni-, Co- or Fe-based alloys containing hard phase carbides at different ratios are commonly used. Tungsten carbides (WC) can provide coating hardness well above 1000 HV (Vickers). In this respect, commercially available WC powders normally contain spherical micro-particles consisting of crushed WC agglomerates. Some years ago, Spherotene powders consisting of spherical-fused monocrystaline WC particles, being extremely hard, between 1800 and 3000 HV, were patented. Very recently, mixtures of Ni-based alloy with Spherotene powders optimized for laser processing were presented (Technolase). These mixtures have been used in our study. Laser cladding tests with these powders were performed on low carbon steel (C25) substrates, and results in terms of microstructure and hardness will be discussed.

  15. Dynamic material properties of refractory metals: tantalum and tantalum/tungsten alloys

    International Nuclear Information System (INIS)

    Furnish, M.D.; Lassila, D.H.; Chhabildas, L.C.; Steinberg, D.J.

    1996-01-01

    We have made a careful set of impact wave-profile measurements (16 profiles) on tantalum and tantalum-tungsten alloys at relatively low stresses (to 15 GPa). Alloys used were Ta 96.5 W 3.5 and Ta 86.5 W 13.5 (wt%) with oxygen contents of 30 endash 70 ppm. Information available from these experiments includes Hugoniot, elastic limits, loading rates, spall strength, unloading paths, reshock structure and specimen thickness effects. Hugoniot and spall properties are illustrated, and are consistent with expectations from earlier work. Modeling the tests with the Steinberg-Guinan-Lund rate-dependent material model provides for an excellent match of the shape of the plastic loading wave. The release wave is not well modeled due to the absence of the dynamic Bauschinger effect. There is also a discrepancy between experiments and calculations regarding the relative timing of the elastic and plastic waves that may be due to texture effects. copyright 1996 American Institute of Physics

  16. Heavy metals in the surface sediments of lakes on the Tibetan Plateau, China.

    Science.gov (United States)

    Guo, Bixi; Liu, Yongqin; Zhang, Fan; Hou, Juzhi; Zhang, Hongbo; Li, Chaoliu

    2018-02-01

    Heavy metal contamination has affected many regions in the world, particularly the developing countries of Asia. We investigated 8 heavy metals (Cu, Zn, Cd, Pb, Cr, Co, Ni, and As) in the surface sediments of 18 lakes on the Tibetan Plateau. It was found that the distributions of the heavy metals showed no clear spatial pattern on the plateau. The results indicated that the mean concentrations of these metals in the sediment samples diminished as follows: Cr > As > Zn > Ni > Pb > Cu > Co > Cd. The results of geoaccumulation index (I geo ) and potential ecological risk factor (E i r ) assessments showed that the sediments were moderately polluted by Cd and As, which posed much higher risks than the other metals. The values of the potential ecological risk index (RI) showed that lake Bieruoze Co has been severely polluted by heavy metals. Principal component analysis, hierarchical cluster analysis, and Pearson correlation analysis results indicated that the 8 heavy metals in the lake surface sediments of the Tibetan Plateau could be classified into four groups. Group 1 included Cu, Zn, Pb, Co, and Ni which were mainly derived from both natural and traffic sources. Group 2 included Cd which mainly originated from anthropogenic sources like alloying, electroplating, and dyeing industries and was transported to the Tibetan Plateau by atmospheric circulation. Group 3 included Cr and it might mainly generate from parent rocks of watersheds. The last Group (As) was mainly from manufacturing, living, and the striking deterioration of atmospheric environment of the West, Central Asia, and South Asia.

  17. Metabolic Demands of Heavy Metal Drumming

    Directory of Open Access Journals (Sweden)

    Bryan Romero

    2016-07-01

    Full Text Available Background: The drum set involves dynamic movement of all four limbs. Motor control studies have been done on drum set playing, yet not much is known about the physiological responses to this activity. Even less is known about heavy metal drumming. Aims: The purpose of this study was to determine metabolic responses and demands of heavy metal drumming. Methods: Five semi-professional male drummers (mean ± SD age = 27.4 ± 2.6 y, height = 177.2 ± 3.8 cm, body mass = 85.1 ± 17.8 kg performed four prescribed and four self-selected heavy metal songs. Oxygen consumption (VO2, minute ventilation (VE and respiratory exchange ratio (RER were measured using a metabolic cart.  Heart rate (HR was measured using a heart rate monitor. VO2max was determined using a graded cycle ergometer test. Results: The results indicated a metabolic cost of 6.3 ± 1.4 METs and heart rate of 145.1 ± 15.7 beats·min-1 (75.4 ± 8.3% of age-predicted HRmax. VO2 peak values reached approximately 90% of the drummer’s VO2max when performing at the fastest speeds. According to these results, heavy metal drumming may be considered vigorous intensity activity (≥ 6.0 METs. The relative VO2max of 40.2 ± 9.5 mL·kg·min-1 leads to an aerobic fitness classification of “average” for adult males. Conclusions: The metabolic demands required during heavy metal drumming meet the American College of Sports Medicine guidelines for the development of health related fitness.  Keywords: Drum set, Exercise physiology, VO2, Music

  18. classification of plants according to their heavy metal content around

    African Journals Online (AJOL)

    Mgina

    accumulated heavy metals around North Mara Gold Mine were not known. To study such ... heavy metal hyperaccumulator plants for possible future remediation of the study area. ... mine is about 100 kilometers east of Lake. Victoria and 20 ...

  19. Evaluation of some heavy metal contaminants in biscuits, fruit drinks ...

    African Journals Online (AJOL)

    Evaluation of some heavy metal contaminants in biscuits, fruit drinks, concentrates, ... effect in human due to continual consumption of food contaminated with heavy metals gotten from raw materials, manufacturing and packaging processes.

  20. Determination of selected heavy metals in inland fresh water of ...

    African Journals Online (AJOL)

    Agadaga

    Key words: Heavy metals, freshwater, concentrations, quality, variation, distribution. ... prevalence of heavy metals in inland water of lower River. Niger drain are scarce ..... Niger waters at Ajaokuta were found to be low and within guideline.

  1. Concentration and Health Implication of Heavy Metals in Drinking ...

    African Journals Online (AJOL)

    Concentration and Health Implication of Heavy Metals in Drinking Water from Urban ... water is not mentioned by WHO, but all the samples analyzed were found to ... Key words: Drinking water quality, Heavy metals, Maximum admissible limit, ...

  2. Phytoremediation of heavy metals with several efficiency enhancer ...

    African Journals Online (AJOL)

    USER

    2010-06-21

    Jun 21, 2010 ... Key words: phytoremediation, heavy metal, plant growth promoting rhizobacteria, multi-functional method. ... population in the twentieth century, heavy metal ... This natural and environmental friendly technology is.

  3. heavy metals and cyanide distribution in the villages surrounding ...

    African Journals Online (AJOL)

    detection limit) were higher in the wells closest to the Tailing Storage Facility ... Key Words: Heavy metals pollution, Total cyanide, ground water pollution and ..... cyanide, heavy metals and probably other hazardous substances, leakage of.

  4. Studies of heavy metal contents and microbial composition of ...

    African Journals Online (AJOL)

    FLEXI-DONEST

    the use of private electricity generating sets, in recent times, have ... soil and evaluate the impact of heavy metal on soil degradable ..... a reasonable length of time by herbivores may .... Heavy Metals in Root, Stem and Leaves of Acalypha.

  5. Effect of solution treatment temperature and cooling rate on the mechanical properties of tungsten heavy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Anjali, E-mail: anjalikumari1261@gmail.com; Prabhu, G.; Sankaranarayana, M.; Nandy, T.K.

    2017-03-14

    The present study investigates the effect of solution treatment temperature and cooling rate on mechanical properties of a tungsten heavy alloy (89.6W-6.2Ni-1.8Fe-2.4Co). In addition to water quenching, rapid argon quenching has been attempted in this study since it is a relatively cleaner process and it can be used in conjunction with vacuum treatment. Since in these alloys, there is a possibility of incomplete dissolution of intermetallics or segregation of impurities during heat treatment, which results in scatter in the mechanical properties, it was decided that the solution treatment temperature for both water and argon quenching would be varied from 1100 to 1250 °C in order to see its effect on the microstructure and mechanical properties. Solution treatment at varying temperatures followed by water quenching resulted in tensile strength ranging from 908 to 921 MPa and % elongation varied from 19% to 26%. On the other hand, the argon quenching heat treatment resulted in tensile strength in the range of 871–955 MPa and % elongation from 9% to 25%. No significant trend with respect to solution treatment temperature on tensile properties was seen in both argon and water quenched samples. % elongation to failure and impact values of water quenched specimens were better than those of argon quenched specimens for a given solution treatment temperature. The impact values appeared to improve with increasing solution treatment temperature in water quenched condition. The properties were correlated with underlying microstructure and fractographs of the failed specimens. The study showed the argon quenching may not be appropriate for the heat treatment of heavy alloys since it results in inferior mechanical properties as compared to water quenching.

  6. Effect of pulsed gas tungsten arc welding on corrosion behavior of Ti-6Al-4V titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanian, M. [Department of Mechanical Engineering, Maamallan Institute of Technology, Anna University, Sriperumpudur 602 105 (India)], E-mail: manianmb@rediffmail.com; Jayabalan, V. [Department of Manufacturing Engineering, Anna University, Guindy, Chennai 600 025 (India)], E-mail: jbalan@annauniv.edu; Balasubramanian, V. [Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002 (India)], E-mail: visvabalu@yahoo.com

    2008-07-01

    Due to the excellent combination of properties such as elevated strength-to-weight ratio, high toughness and excellent resistance to corrosion, make titanium alloys attractive for many industrial applications. Advantages of pulsed current welding frequently reported in literature include refinement of fusion zone grain size, etc. Hence, in this investigation an attempt has been made to study the effect of pulsed current Gas Tungsten Arc (GTA) welding parameters on corrosion behavior of Ti-6Al-4V titanium alloy. Pulsed current gas tungsten arc welding was used to fabricate the joints. To optimize the number of experiments to be performed, central composite design was used. The investigation revealed increase in corrosion resistance with increase in peak current and pulse frequency up to an optimum value of the same and decrease in corrosion resistance beyond that optimum point. An increase in corrosion resistance with grain refinement was also detected.

  7. Effect of pulsed gas tungsten arc welding on corrosion behavior of Ti-6Al-4V titanium alloy

    International Nuclear Information System (INIS)

    Balasubramanian, M.; Jayabalan, V.; Balasubramanian, V.

    2008-01-01

    Due to the excellent combination of properties such as elevated strength-to-weight ratio, high toughness and excellent resistance to corrosion, make titanium alloys attractive for many industrial applications. Advantages of pulsed current welding frequently reported in literature include refinement of fusion zone grain size, etc. Hence, in this investigation an attempt has been made to study the effect of pulsed current Gas Tungsten Arc (GTA) welding parameters on corrosion behavior of Ti-6Al-4V titanium alloy. Pulsed current gas tungsten arc welding was used to fabricate the joints. To optimize the number of experiments to be performed, central composite design was used. The investigation revealed increase in corrosion resistance with increase in peak current and pulse frequency up to an optimum value of the same and decrease in corrosion resistance beyond that optimum point. An increase in corrosion resistance with grain refinement was also detected

  8. Evaluation of mechanically alloyed Cu-based powders as filler alloy for brazing tungsten to a reduced activation ferritic-martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Prado, J. de, E-mail: javier.deprado@urjc.es; Sánchez, M.; Ureña, A.

    2017-07-15

    80Cu-20Ti powders were evaluated for their use as filler alloy for high temperature brazing of tungsten to a reduced activation ferritic/martensitic steel (Eurofer), and its application for the first wall of the DEMO fusion reactor. The use of alloyed powders has not been widely considered for brazing purposes and could improve the operational brazeability of the studied system due to its narrower melting range, determined by DTA analysis, which enhances the spreading capabilities of the filler. Ti contained in the filler composition acts as an activator element, reacting and forming several interfacial layers at the Eurofer-braze, which enhances the wettability properties and chemical interaction at the brazing interface. Brazing thermal cycle also activated the diffusion phenomena, which mainly affected to the Eurofer alloying elements causing in it a softening band of approximately 400 μm of thickness. However, this softening effect did not degrade the shear strength of the brazed joints (94 ± 23 MPa), because failure during testing was always located at the tungsten-braze interface. - Highlights: •W-Eurofer brazed joints, manufactured using Cu-based mechanically alloyed powders as filler is proposed. •The benefits derivate from the alloyed composition could improve the operational brazeability of the studied system. •Tested pre-alloyed fillers have a more homogeneous melting stage which enhances its spreading and flowing capabilities. •This behaviour could lead to work with higher heating rates and lower brazing temperatures.

  9. Structure and phase transformation behavior of electroless Ni-P alloys containing tin and tungsten

    International Nuclear Information System (INIS)

    Balaraju, J.N.; Jahan, S. Millath; Jain, Anjana; Rajam, K.S.

    2007-01-01

    Autocatalytic ternary Ni-Sn-P, Ni-W-P and quaternary Ni-W-Sn-P films were prepared using alkaline citrate-based baths and compared with binary Ni-P coatings. Energy dispersive analysis of X-ray (EDAX) showed that binary Ni-P deposit contained 11.3 wt.% of phosphorus. Codeposition of tungsten in Ni-P matrix resulted in ternary Ni-W-P with 5 wt.% P and 7.8 wt.% of tungsten. Incorporation of tin led to ternary Ni-Sn-P deposit containing 0.4 wt.% Sn and 10.3 wt.% P. Presence of both sodium tungstate and sodium stannate in the basic bath had resulted in quaternary coating with 6.9 wt.% W, traces of Sn and 6.4 wt.% P. X-ray diffraction patterns of all the deposits revealed a single, broad peak which showed the nanocrystalline nature of the deposits. For the first time in related literature, the presence of a metastable phase Ni 12 P 5 in ternary deposits is reported in the present study. Metallographic cross-sections of all the deposits revealed the banded/lamellar structure. Scanning electron microscopy (SEM) studies of the deposits showed smooth nodules for ternary deposits, but coarse and well-defined nodules for quaternary deposits. DSC studies of phase transformation behavior of the ternary Ni-Sn-P deposit revealed a single sharp exothermic peak at 365 o C. However, ternary Ni-W-P and quaternary Ni-W-Sn-P deposits exhibited a low temperature peak at 300 o C, a split type high temperature peak at 405 and 440 o C and a very high temperature peak at 550 o C. Higher activation energy values were obtained for W-based alloy deposits. Presence of W and Sn has helped to retain high microhardness values even at higher temperatures indicating an improved thermal stability

  10. Transfer of heavy metals through terrestrial food webs: a review.

    Science.gov (United States)

    Gall, Jillian E; Boyd, Robert S; Rajakaruna, Nishanta

    2015-04-01

    Heavy metals are released into the environment by both anthropogenic and natural sources. Highly reactive and often toxic at low concentrations, they may enter soils and groundwater, bioaccumulate in food webs, and adversely affect biota. Heavy metals also may remain in the environment for years, posing long-term risks to life well after point sources of heavy metal pollution have been removed. In this review, we compile studies of the community-level effects of heavy metal pollution, including heavy metal transfer from soils to plants, microbes, invertebrates, and to both small and large mammals (including humans). Many factors contribute to heavy metal accumulation in animals including behavior, physiology, and diet. Biotic effects of heavy metals are often quite different for essential and non-essential heavy metals, and vary depending on the specific metal involved. They also differ for adapted organisms, including metallophyte plants and heavy metal-tolerant insects, which occur in naturally high-metal habitats (such as serpentine soils) and have adaptations that allow them to tolerate exposure to relatively high concentrations of some heavy metals. Some metallophyte plants are hyperaccumulators of certain heavy metals and new technologies using them to clean metal-contaminated soil (phytoextraction) may offer economically attractive solutions to some metal pollution challenges. These new technologies provide incentive to catalog and protect the unique biodiversity of habitats that have naturally high levels of heavy metals.

  11. Phytoremediation of water bodies contaminated with radioactive heavy metal

    International Nuclear Information System (INIS)

    Yan Zhen; Yuan Shichao; Ling Hui; Xie Shuibo

    2012-01-01

    The sources of the radioactive heavy metal in the water bodies were analyzed. The factors that affect phyto remediation of water contaminated with radioactive heavy metal were discussed. The plant species, mechanism and major technology of phyto remediation of water contaminated with radioactive heavy metal were particularly introduced. The prospective study was remarked. (authors)

  12. Heavy metals content in the stem bark of Detarium microcarpum ...

    African Journals Online (AJOL)

    The heavy metal analysis was carried out on the stem bark of D. microcarpum using an atomic absorption spectrophotometer (AAS). The heavy metals screened for include: lead, chromium, manganese, zinc and iron. The levels of manganese, zinc and iron were 13.91, 4.89 and 21.89 mg/L respectively. These heavy metals ...

  13. Arbuscular Mycorrhizal Fungi Can Benefit Heavy Metal Tolerance and Phytoremediation

    Science.gov (United States)

    Forgy, David

    2012-01-01

    Sites contaminated by heavy metals, such as industrial waste sites, create unwelcoming environments for plant growth. Heavy metals can have a wide range of toxic effects such as replacing essential elements or disrupting enzyme function. While some heavy metals are essential to plant nutrition at low concentrations, high concentrations of any…

  14. Classification of Plants According to Their Heavy Metal Content ...

    African Journals Online (AJOL)

    Plants like other living organisms respond differently under different environmental conditions. An elevated level of heavy metals is one of the stresses which results into three classes of plants depending on their heavy metal content. The classes of plant species according to their accumulated heavy metals around North ...

  15. Bioaccumulation and toxic effects of some heavy metals in ...

    African Journals Online (AJOL)

    The contamination of the aquatic systems with heavy metals from natural anthropogenic sources has become a global problem which poses threats to ecosystems and natural communities. Hence this study reviews the effects of heavy metals in freshwater fishes. Fishes bioaccumulate heavy metals (including cadmium, zinc ...

  16. Tungsten silicide contacts to polycrystalline silicon and silicon-germanium alloys

    International Nuclear Information System (INIS)

    Srinivasan, G.; Bain, M.F.; Bhattacharyya, S.; Baine, P.; Armstrong, B.M.; Gamble, H.S.; McNeill, D.W.

    2004-01-01

    Silicon-germanium alloy layers will be employed in the source-drain engineering of future MOS transistors. The use of this technology offers advantages in reducing series resistance and decreasing junction depth resulting in reduction in punch-through and SCE problems. The contact resistance of metal or metal silicides to the raised source-drain material is a serious issue at sub-micron dimensions and must be minimised. In this work, tungsten silicide produced by chemical vapour deposition has been investigated as a contact metallization scheme to both boron and phosphorus doped polycrystalline Si 1- x Ge x , with 0 ≤x ≤ 0.3. Cross bridge Kelvin resistor (CKBR) structures were fabricated incorporating CVD WSi 2 and polycrystalline SiGe. Tungsten silicide contacts to control polysilicon CKBR structures have been shown to be of high quality with specific contact resistance ρ c values 3 x 10 -7 ohm cm 2 and 6 x 10 -7 ohm cm 2 obtained to boron and phosphorus implanted samples respectively. The SiGe CKBR structures show that the inclusion of Ge yields a reduction in ρ c for both dopant types. The boron doped SiGe exhibits a reduction in ρ c from 3 x 10 -7 to 5 x 10 -8 ohm cm 2 as Ge fraction is increased from 0 to 0.3. The reduction in ρ c has been shown to be due to (i) the lowering of the tungsten silicide Schottky barrier height to p-type SiGe resulting from the energy band gap reduction, and (ii) increased activation of the implanted boron with increased Ge fraction. The phosphorus implanted samples show less sensitivity of ρ c to Ge fraction with a lowest value in this work of 3 x 10 -7 ohm cm 2 for a Ge fraction of 0.3. The reduction in specific contact resistance to the phosphorus implanted samples has been shown to be due to increased dopant activation alone

  17. Thermal conduction and linear expansion of sintered rhenium and tungsten-rhenium alloys at a temperature up to 1000 K

    International Nuclear Information System (INIS)

    Pozdnyak, N.Z.; Belyaev, R.A.; Vavilov, Yu.V.; Vinogradov, Yu.G.; Serykh, G.M.

    1978-01-01

    Preparation technology (by powder metallurgy methods) of sintered rhenium and tungsten-rhenium VR-5, VR-10, and VR-20 alloys is described. Thermal conduction of rhenium and VR-20 alloy has been measured in the temperature range from 300 to 1000 K. The value obtained turned out to be considerably less than those published elsewhere, this testifies to the great thermal contact resistance between the material grains. Also measured is the mean linear expansion coefficient for the mentioned above materials in the same temperature range. Linear expansion increases with rhenium content increase

  18. Effects of Tungsten Addition on the Microstructure and Corrosion Resistance of Fe-3.5B Alloy in Liquid Zinc

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2017-04-01

    Full Text Available The effects of tungsten addition on the microstructure and corrosion resistance of Fe-3.5B alloys in a liquid zinc bath at 520 °C were investigated by means of scanning electron microscopy, X-ray diffraction and electron probe micro-analysis. The microstructure evolution in different alloys is analyzed and discussed using an extrapolated Fe-B-W ternary phase diagram. Experimental results show that there are three kinds of borides, the reticular (Fe, W2B, the rod-like (Fe, W3B and flower-like FeWB. The addition of tungsten can refine the microstructure and improve the stability of the reticular borides. Besides, it is beneficial to the formation of the metastable (Fe, W3B phase. The resultant Fe-3.5B-11W (wt % alloy possesses excellent corrosion resistance to liquid zinc. When tungsten content exceeds 11 wt %, the formed flower-like FeWB phase destroys the integrity of the reticular borides and results in the deterioration of the corrosion resistance. Also, the corrosion failure resulting from the spalling of borides due to the initiation of micro-cracks in the grain boundary of borides is discussed in this paper.

  19. Investigation of LMFBR prototype 7A heaters and the metallurgy of the platinum-8 weight percent tungsten alloy

    International Nuclear Information System (INIS)

    Ludwig, R.L.

    1976-09-01

    A Liquid Metal Fast Breeder Reactor 7A prototype heater failure was analyzed. The failure was due to melting of the platinum-8 weight percent tungsten alloy (Pt-8 W) alloy winding caused by a loss of contact with the inside boron nitride insulation. An attempt to simulate a failure revealed that elemental boron forms a low-melting mixture with Pt-8 W, but a means by which boron might be present in an actual heater was not determined. A time/temperature/grain size study of various Pt-8 W alloy samples resulted in behavior which would be expected from a single-phase, solid-solution alloy. The results of the study were useful in estimating the temperatures reached at various locations along the length of two failed 7A prototype heaters

  20. The role of iridium in the work-function behavior of dilute-solution tungsten, iridium alloys

    International Nuclear Information System (INIS)

    D'Cruz, L.A.

    1991-01-01

    Requirements of thermionic electrode materials have emphasized the need for substantial improvements in microstructural stability, strength and creep resistance at service temperatures in excess of 2,500K. This study utilized both chemical alloying and mechanical alloying procedures for the addition of iridium to submicron W powder followed by cold compaction and sintering. The shrinkage characteristics and microstructural development were studied in iridium-added tungsten compacts with a range of additive levels. An electron-emission study was subsequently carried out in order to evaluate the work-function behavior of the consolidated alloys. The work function was obtained from current-emission measurements from the electrode surface under UHV conditions in the temperature range of 1,800 to 2,500K using a Vacuum Emission Vehicle (VEV). The data show that the magnitude of the work function in these alloys varied with temperature and was sensitive to sub-surface iridium content

  1. Joint properties of dissimilar Al6061-T6 aluminum alloy/Ti–6%Al–4%V titanium alloy by gas tungsten arc welding assisted hybrid friction stir welding

    International Nuclear Information System (INIS)

    Bang, HanSur; Bang, HeeSeon; Song, HyunJong; Joo, SungMin

    2013-01-01

    Highlights: • Hybrid friction stir welding for Al alloy and Ti alloy joint has been carried out. • Mechanical strength of dissimilar joint by HFSW and FSW has been compared. • Microstructure of dissimilar joint by HFSW and FSW has been compared. - Abstract: Hybrid friction stir butt welding of Al6061-T6 aluminum alloy plate to Ti–6%Al–4%V titanium alloy plate with satisfactory acceptable joint strength was successfully achieved using preceding gas tungsten arc welding (GTAW) preheating heat source of the Ti alloy plate surface. Hybrid friction stir welding (HFSW) joints were welded completely without any unwelded zone resulting from smooth material flow by equally distributed temperature both in Al alloy side and Ti alloy side using GTAW assistance for preheating the Ti alloy plate unlike friction stir welding (FSW) joints. The ultimate tensile strength was approximately 91% in HFSW welds by that of the Al alloy base metal, which was 24% higher than that of FSW welds without GTAW under same welding condition. Notably, it was found that elongation in HFSW welds increased significantly compared with that of FSW welds, which resulted in improved joint strength. The ductile fracture was the main fracture mode in tensile test of HFSW welds

  2. Heavy metal pollutant tolerance of Azolla pinnata

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, A.; Jana, S.

    1986-01-01

    The effects of Hg, As, Pb, Cu, Cd, and Cr (1,2 and 5 mg L/sup -1/ each) on Azolla pinnata R. Br. were analyzed. The treatments (2 and 5 mg L/sup -1/) of the heavy metal pollutants decreased Hill activity, chlorophyll, protein and dry wt, and increased tissue permeability over control values. The effects were most pronounced with the treatment of 5 mg L/sup -1/. The harmful effects of the metals were, in general, found by the treatments in the order: Cd > Hg > Cu > As > Pb > Cr. There was no significant change in these parameters at 1 mg L/sup -1/ of the metals over control. Thus Azolla pinnata shows tolerance to the heavy metals tested up to 1 mg L/sup -1/ each.

  3. Leaching of heavy metals from steelmaking slags

    International Nuclear Information System (INIS)

    Gomez, J. F. P.; Pino, C. G.

    2006-01-01

    Leaching tests with EAF and Ladle slags were performed, using a flow through tests and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. the chemical analysis of the leachates during this period shows, in general, for both types of slag, and increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slang samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-though test, calcium and magnesium leached from solid slags are below 0.5% and all other metals below 0.1%. Leachates obtained with DIN 38414-S4 present, as expected, higher leaching values; however, these are inferior to 5% (Ca) and 1% (other elements). (Author) 12 refs

  4. Esterase resistant to inactivation by heavy metals

    KAUST Repository

    El, Dorry Hamza

    2014-09-25

    EstATII is an esterase that a halotolerant, thermophilic and resistant to a spectrum of heavy metals including toxic concentration of metals. It was isolated from the lowest convective layer of the Atlantis II Red Sea brine pool. The Atlantis II brine pool is an extreme environment that possesses multiple harsh conditions such as; high temperature, salinity, pH and high concentration of metals, including toxic heavy metals. A fosmid metagenomic library using DNA isolated from the lowest convective layer this pool was used to identify EstATII. Polynucleotides encoding EstATII and similar esterases are disclosed and can be used to make EstATII. EstATII or compositions or apparatuses that contain it may be used in various processes employing lipases/esterases especially when these processes are performed under harsh conditions that inactivate other kinds of lipases or esterases.

  5. Electrodialytic remediation of heavy metal polluted soil

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Jensen, Pernille Erland; Kirkelund, Gunvor Marie

    2012-01-01

    Electrodialytic soil remediation is a method for removal of heavy metals. Good results have previously been obtained with both treatment of a stationary, water saturated soil matrix and with remediation of a stirred suspension of soil in water. The two different setups have different uses....... The first as in-situ or on-site treatment when there is no requirement for fast remediation, as the removal rate of the heavy metals are dependent on the distance between the electrodes (everything else equal) and in such application the electrode spacing must have a certain distance (often meters......). In the stirred setup it is possible to shorten the transport route to few mm and to have a faster and continuous process. The present paper for the first time reports a direct comparison of the two options. The remediation of the stirred suspension showed faster than remediation of the water saturated soil even...

  6. Heavy metals in the hydrological cycle

    International Nuclear Information System (INIS)

    Astruc, M.; Lester, J.N.

    1988-01-01

    An integrated approach to the problems associated with heavy metals in the hydrological cycle is presented. Research and practical experience from a broad spectrum of disciplines are drawn together concentrating on the following themes: water quality, domestic and industrial wastes, sludge and dredge materials, soil interactions, effects on aquatic ecosystems, organometallics (with particular reference to tin compounds), speciation, the marine environment and health effects. One paper is within INIS scope and is processed separately. (U.K.)

  7. Heavy metals in carabids (Coleoptera, Carabidae

    Directory of Open Access Journals (Sweden)

    Ruslan Butovsky

    2011-05-01

    Full Text Available Carabid beetles (Coleoptera, Carabidae are one of the most studied soil groups in relation to heavy metal (HM accumulation and use for bioindication of environmental pollution. Accumulation of Zn and Cu in carabid beetles was species-, sex- and trophic group-specific. No differences were found in HM contents between omnivorous and carnivorous species. The use of carabid beetles as indicators of HM accumulation appears to be rather limited.

  8. Uranium and heavy metals in phosphate fertilizers

    International Nuclear Information System (INIS)

    Khater, Ashraf E.M.; King Saud University, Riyadh

    2008-01-01

    Full text: Agricultural applications of chemical fertilizers are a worldwide practice. The specific activity of uranium-238 and heavy metals in phosphate fertilizers depends on the phosphate ore from which the fertilizer produced and on the chemical processing of the ore. Composite phosphate fertilizers samples were collected and the uranium-238 specific activity, in Bq/kg, and As, Cd, Cu, Pb, Se concentration were measured. The annual addition of these elements in soil due to soil fertilization were calculated and discussed. (author)

  9. Polution of the environment by heavy metals

    International Nuclear Information System (INIS)

    Houtman, J.P.W.

    1980-01-01

    An overview is given of the problems caused by pollution of the environment by heavy metals and the important role played by nuclear examination methods such as activation analysis and particle induced X-ray emission. A number of examples taken from work initiated by the interuniversitair Reactor Instituut, demonstrate that this research should be continued and extended, particularly in relation to the expected increase in the use of coal for energy generation in electricity centres. (C.F.)

  10. Pyrolized biochar for heavy metal adsorption

    Science.gov (United States)

    Removal of copper and lead metal ions from water using pyrolized plant materials. Method can be used to develop a low cost point-of-use device for cleaning contaminated water. This dataset is associated with the following publication:DeMessie, B., E. Sahle-Demessie , and G. Sorial. Cleaning Water Contaminated With Heavy Metal Ions Using Pyrolyzed Banana Peel Adsorbents. Separation Science and Technology. Marcel Dekker Incorporated, New York, NY, USA, 50(16): 2448-2457, (2015).

  11. The remediation of heavy metals contaminated sediment.

    Science.gov (United States)

    Peng, Jian-Feng; Song, Yong-Hui; Yuan, Peng; Cui, Xiao-Yu; Qiu, Guang-Lei

    2009-01-30

    Heavy metal contamination has become a worldwide problem through disturbing the normal functions of rivers and lakes. Sediment, as the largest storage and resources of heavy metal, plays a rather important role in metal transformations. This paper provides a review on the geochemical forms, affecting factors and remediation technologies of heavy metal in sediment. The in situ remediation of sediment aims at increasing the stabilization of some metals such as the mobile and the exchangeable fractions; whereas, the ex situ remediation mainly aims at removing those potentially mobile metals, such as the Mn-oxides and the organic matter (OM) fraction. The pH and OM can directly change metals distribution in sediment; however oxidation-reduction potential (ORP), mainly through changing the pH values, indirectly alters metals distribution. Mainly ascribed to their simple operation mode, low costs and fast remediation effects, in situ remediation technologies, especially being fit for slight pollution sediment, are applied widely. However, for avoiding metal secondary pollution from sediment release, ex situ remediation should be the hot point in future research.

  12. Customizable Biopolymers for Heavy Metal Remediation

    International Nuclear Information System (INIS)

    Kostal, Jan; Prabhukumar, Giridhar; Lao, U. Loi; Chen Alin; Matsumoto, Mark; Mulchandani, Ashok; Chen, Wilfred

    2005-01-01

    Nanoscale materials have been gaining increasing interest in the area of environmental remediation because of their unique physical, chemical and biological properties. One emerging area of research has been the development of novel materials with increased affinity, capacity, and selectivity for heavy metals because conventional technologies are often inadequate to reduce concentrations in wastewater to acceptable regulatory standards. Genetic and protein engineering have emerged as the latest tools for the construction of nanoscale materials that can be controlled precisely at the molecular level. With the advent of recombinant DNA techniques, it is now possible to create 'artificial' protein polymers with fundamentally new molecular organization. The most significant feature of these nanoscale biopolymers is that they are specifically pre-programmed within a synthetic gene template and can be controlled precisely in terms of sizes, compositions and functions at the molecular level. In this review, the use of specifically designed protein-based nano-biomaterials with both metal-binding and tunable properties for heavy metal removal is summarized. Several different strategies for the selective removal of heavy metals such as cadmium and mercury are highlighted

  13. Heavy metals and related trace elements

    International Nuclear Information System (INIS)

    Leland, H.V.; Luoma, S.N.; Wilkes, D.J.

    1977-01-01

    A review is given of heavy metals and related trace elements in the aquatic environment. Other reviews and bibliographies are cited, dealing with the metabolism and transport of metal ions and with the toxic effects of stable and radioactive trace metals on aquatic organisms. The sources of trace elements in natural waters are discussed. It is suggested that atmospheric inputs of several trace metals comprise sizable fractions of total inputs to the Great Lakes and continental shelf waters. Information on stack emissions of trace elements from a coal-fired steam plant was used to estimate the likely range of air concentrations and inputs to a forested watershed in Tennessee. Some basic concepts of cycling of elements through aquatic communities were examined, such as the Pb, Mn and Zn concentrations in sediment and estuarine plants and animals colonizing dredge-spoil disposal areas. The use of plants as biological indicators of trace element contamination was outlined, as well as bioaccumulation in aquatic fauna. The effects of environmental factors on the kinetics of element exchange were noted, for example the influx rates of Cs 137 in tubificid worms, and Co 60 and Zn 65 in shrimp were shown to be temperature dependent. The toxicity of heavy metals on aquatic fauna was discussed, such as the histopathological lesions in the kidney and liver of fishes caused by heavy metals, and the effects of Hg and Cu on the olfactory response of rainbow trout

  14. Heavy metals hazards from Nigerian spices.

    Science.gov (United States)

    Asomugha, Rose Ngozi; Udowelle, Nnaemeka Arinze; Offor, Samuel James; Njoku, Chinonso Judith; Ofoma, Ifeoma Victoria; Chukwuogor, Chiaku Chinwe; Orisakwe, Orish Ebere

    Natural spices are commonly used by the people in Nigeria. They may be easily contaminated with heavy metals when they are dried and then pose a health risk for the consumers. The aim of this study was to determine the levels of heavy metals in some commonly consumed natural spices namely Prosopis Africana, Xylopia aethiopica, Piper gineense, Monodora myristica, Monodora tenuifolia and Capsicum frutescens sold in the local markets of Awka, Anambra state, South East Nigeria to estimate the potential health risk. The range of heavy metal concentration was in the order: Zn (14.09 - 161.04) > Fe (28.15 - 134.59) > Pb (2.61 - 8.97) > Cr (0.001 - 3.81) > Co (0.28 - 3.07) > Ni (0.34 - 2.89). Pb, Fe and Zn exceeded the maximum allowable concentrations for spices. The Target Hazard Quotient (THQ) of the spices varied from 0.06-0.5. Estimated daily intakes (EDI) were all below the tolerable daily intake (TDI). The lead levels in Prosopis africana, Xylopia aethiopica, Piper gineense, Monodora myristica and Capsicum frutescens which are 8-30 times higher than the WHO/FAO permissible limit of 0.3 mg/kg. Lead contamination of spices sold in Awka (south east Nigeria) may add to the body burden of lead. A good quality control for herbal food is important in order to protect consumers from contamination. food products, spices, potential toxic metals, risk assessment, public health.

  15. Heavy metal emissions for Danish road transport

    Energy Technology Data Exchange (ETDEWEB)

    Winther, M.; Slentoe, E.

    2010-04-15

    This report presents new heavy metal emission factors for cars, vans, trucks, buses, mopeds and motorcycles for each of the emission sources fuel consumption, engine oil, tyre wear, brake wear and road abrasion. The emission components covered are Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Mercury (Hg), Nickel (Ni), Lead (Pb), Selenium (Se) and Zinc (Zn), all of them relevant for emission reporting to the UNECE CLRTAP (United Nations Economic Commission for Europe Convention on Long Range Transboundary Pollutants) convention. The report also presents a new Danish inventory for the year 2007. The following emissions in total TSP (in brackets) are calculated for the year 2007: As (8 kg), Cd (48 kg), Cr (197 kg), Cu (51 779 kg), Hg (28 kg), Ni (158 kg), Pb (6 989 kg), Se (33 kg) and Zn (28 556 kg). Per vehicle type cars are the most important source of emission for all heavy metal species, followed by vans, trucks, buses and 2-wheelers. By using the detailed emission factors and inventory calculation methods established in the present project, estimates of heavy metal emissions can be made for other years than 2007. (author)

  16. [Research advances in heavy metals pollution ecology of diatom].

    Science.gov (United States)

    Ding, Teng-Da; Ni, Wan-Min; Zhang, Jian-Ying

    2012-03-01

    Diatom, due to its high sensitivity to environmental change, is one of the bio-indicators of aquatic ecosystem health, and some typical diatom species have been applied to indicate the heavy metals pollution of water body. With the focus on the surface water heavy metals pollution, this paper reviewed the research advances in the toxic effect of heavy metals pollution on diatom, biosorption and bioaccumulation of heavy metals by diatom, ecological adaptation mechanisms of diatom to heavy metals pollution, and roles of diatom as bio-indicator and in ecological restoration of heavy metals pollution. The growth tendency of diatom and the morphological change of frustule under heavy metals pollution as well as the differences in heavy metals biosorption and bioaccumulation by diatom, the ecological adaptation mechanisms of diatom on heavy metals surface complexation and ion exchange, and the roles of diatom as bio-indicator and in ecological restoration of heavy metals polluted water body were also discussed. This review could provide scientific evidences for the prevention of aquatic ecosystems heavy metals pollution and related early warning techniques.

  17. Processing and structure of in situ Fe-Al alloys produced by gas tungsten arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center

    1997-02-14

    Iron aluminide weld overlays are being investigated for corrosion and erosion protection of boiler tubes in low NOx burners. The primary objective of the research is to identify overlay compositions which can be deposited in a crack-free condition and provide corrosion protection in moderately reducing environments. In the current phase of work, Fe-Al alloy weld overlays were produced by depositing commercially pure aluminum wire on to low carbon steel substrates using Gas Tungsten Arc Welding. A systematic variation of the wire feed speed and current, two major factors affecting dilution, resulted in a variation in aluminum contents of the welds ranging from 3--42 wt% aluminum. The aluminum content was observed to increase with wire feed speed and a decrease in the current. The aluminum content was also found to affect the cracking susceptibility of the overlays. At 10wt% aluminum, few to no cracks were observed in the deposits. Above this value, cracking was prevalent throughout the weld. In addition, two types of microstructures were found correlating to different concentrations of aluminum. A homogeneous matrix with second phase particles consisting of coarse columnar grains was found for low aluminum concentrations. With higher aluminum contents, a two-phase constituent was observed to surround primary dendrites growing from the substrate. The transition of the microstructures occurred between 24 and 32 wt% Al.

  18. Electrochemical Testing of Gas Tungsten Arc Welded and Reduced Pressure Electron Beam Welded Alloy 22

    International Nuclear Information System (INIS)

    Day, S D; Wong, F G; Gordon, S R; Wong, L L; Rebak, R B

    2006-01-01

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIG method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. It was of interest to compare the corrosion properties of specimens prepared using both types of welding techniques. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal (non-welded) to determine their relative corrosion behavior in simulated concentrated water (SCW) at 90 C (alkaline), 1 M HCl at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the same electrochemical behavior in the three tested electrolytes

  19. Electrochemical Testing of Gas Tungsten ARC Welded and Reduced Pressure Electron Beam Welded Alloy 22

    International Nuclear Information System (INIS)

    S. Daniel Day; Frank M.G. Wong; Steven R. Gordon; Lana L. Wong; Raul B. Rebak

    2006-01-01

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIC method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. It was of interest to compare the corrosion properties of specimens prepared using both types of welding techniques. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal (non-welded) to determine their relative corrosion behavior in simulated concentrated water (SCW) at 90 C (alkaline), 1 M HCI at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the same electrochemical behavior in the three tested electrolytes

  20. Characterization and cytotoxic assessment of ballistic aerosol particulates for tungsten alloy penetrators into steel target plates.

    Science.gov (United States)

    Machado, Brenda I; Murr, Lawrence E; Suro, Raquel M; Gaytan, Sara M; Ramirez, Diana A; Garza, Kristine M; Schuster, Brian E

    2010-09-01

    The nature and constituents of ballistic aerosol created by kinetic energy penetrator rods of tungsten heavy alloys (W-Fe-Ni and W-Fe-Co) perforating steel target plates was characterized by scanning and transmission electron microscopy. These aerosol regimes, which can occur in closed, armored military vehicle penetration, are of concern for potential health effects, especially as a consequence of being inhaled. In a controlled volume containing 10 equispaced steel target plates, particulates were systematically collected onto special filters. Filter collections were examined by scanning and transmission electron microscopy (SEM and TEM) which included energy-dispersive (X-ray) spectrometry (EDS). Dark-field TEM identified a significant nanoparticle concentration while EDS in the SEM identified the propensity of mass fraction particulates to consist of Fe and FeO, representing target erosion and formation of an accumulating debris field. Direct exposure of human epithelial cells (A549), a model for lung tissue, to particulates (especially nanoparticulates) collected on individual filters demonstrated induction of rapid and global cell death to the extent that production of inflammatory cytokines was entirely inhibited. These observations along with comparisons of a wide range of other nanoparticulate species exhibiting cell death in A549 culture may suggest severe human toxicity potential for inhaled ballistic aerosol, but the complexity of the aerosol (particulate) mix has not yet allowed any particular chemical composition to be identified.

  1. Characterization and Cytotoxic Assessment of Ballistic Aerosol Particulates for Tungsten Alloy Penetrators into Steel Target Plates

    Directory of Open Access Journals (Sweden)

    Brian E. Schuster

    2010-08-01

    Full Text Available The nature and constituents of ballistic aerosol created by kinetic energy penetrator rods of tungsten heavy alloys (W-Fe-Ni and W-Fe-Co perforating steel target plates was characterized by scanning and transmission electron microscopy. These aerosol regimes, which can occur in closed, armored military vehicle penetration, are of concern for potential health effects, especially as a consequence of being inhaled. In a controlled volume containing 10 equispaced steel target plates, particulates were systematically collected onto special filters. Filter collections were examined by scanning and transmission electron microscopy (SEM and TEM which included energy-dispersive (X-ray spectrometry (EDS. Dark-field TEM identified a significant nanoparticle concentration while EDS in the SEM identified the propensity of mass fraction particulates to consist of Fe and FeO, representing target erosion and formation of an accumulating debris field. Direct exposure of human epithelial cells (A549, a model for lung tissue, to particulates (especially nanoparticulates collected on individual filters demonstrated induction of rapid and global cell death to the extent that production of inflammatory cytokines was entirely inhibited. These observations along with comparisons of a wide range of other nanoparticulate species exhibiting cell death in A549 culture may suggest severe human toxicity potential for inhaled ballistic aerosol, but the complexity of the aerosol (particulate mix has not yet allowed any particular chemical composition to be identified.

  2. Bioremediation of Heavy Metal by Algae

    Directory of Open Access Journals (Sweden)

    Seema Dwivedi

    2012-07-01

    Full Text Available Instead of using mainly bacteria, it is also possible to use mainly algae to clean wastewater because many of the pollutant sources in wastewater are also food sources for algae. Nitrates and phosphates are common components of plant fertilizers for plants. Like plants, algae need large quantities of nitrates and phosphates to support their fast cell cycles. Certain heavy metals are also important for the normal functioning of algae. These include iron (for photosynthesis, and chromium (for metabolism. Because marine environments are normally scarce in these metals, some marine algae especially have developed efficient mechanisms to gather these heavy metals from the environment and take them up. These natural processes can also be used to remove certain heavy metals from the environment. The use of algae has several advantages over normal bacteria-based bioremediation processes. One major advantage in the removal of pollutants is that this is a process that under light conditions does not need oxygen. Instead, as pollutants are taken up and digested, oxygen is added while carbon dioxide is removed. Hence, phytoremediation could potentially be coupled with carbon sequestration. Additionally, because phytoremediation does not rely on fouling processes, odors are much less a problem. Microalgae, in particular, have been recognized as suitable vectors for detoxification and have emerged as a potential low-cost alternative to physicochemical treatments. Uptake of metals by living microalgae occurs in two steps: one takes place rapidly and is essentially independent of cell metabolism – “adsorption” onto the cell surface. The other one is lengthy and relies on cell metabolism – “absorption” or “intracellular uptake.” Nonviable cells have also been successfully used in metal removal from contaminated sites. Some of the technologies in heavy metal removals, such as High Rate Algal Ponds and Algal Turf Scrubber, have been justified for

  3. Experimental investigations of visco-plastic properties of the aluminium and tungsten alloys used in KE projectiles

    Science.gov (United States)

    Kruszka, L.; Magier, M.

    2012-08-01

    The main aim of studies on dynamic behaviour of construction materials at high strain rates is to determine the variation of mechanical properties (strength, plasticity) in function of the strain rate and temperature. On the basis of results of dynamic tests on the properties of constructional materials the constitutive models are formulated to create numerical codes applied to solve constructional problems with computer simulation methods. In the case of military applications connected with the phenomena of gunshot and terminal ballistics it's particularly important to develop a model of strength and armour penetration with KE projectile founded on reliable results of dynamic experiments and constituting the base for further analyses and optimization of projectile designs in order to achieve required penetration depth. Static and dynamic results of strength investigations of the EN AW-7012 aluminium alloy (sabot) and tungsten alloy (penetrator) are discussed in this paper. Static testing was carried out with the INSTRON testing machine. Dynamic tests have been conducted using the split Hopkinson pressure bars technique at strain rates up to 1,2 ṡ 104s-1 (for aluminium alloy) and 6 ṡ 103s-1 (for tungsten alloy).

  4. Experimental investigations of visco-plastic properties of the aluminium and tungsten alloys used in KE projectiles

    Directory of Open Access Journals (Sweden)

    Magier M.

    2012-08-01

    Full Text Available The main aim of studies on dynamic behaviour of construction materials at high strain rates is to determine the variation of mechanical properties (strength, plasticity in function of the strain rate and temperature. On the basis of results of dynamic tests on the properties of constructional materials the constitutive models are formulated to create numerical codes applied to solve constructional problems with computer simulation methods. In the case of military applications connected with the phenomena of gunshot and terminal ballistics it’s particularly important to develop a model of strength and armour penetration with KE projectile founded on reliable results of dynamic experiments and constituting the base for further analyses and optimization of projectile designs in order to achieve required penetration depth. Static and dynamic results of strength investigations of the EN AW-7012 aluminium alloy (sabot and tungsten alloy (penetrator are discussed in this paper. Static testing was carried out with the INSTRON testing machine. Dynamic tests have been conducted using the split Hopkinson pressure bars technique at strain rates up to 1,2 ⋅ 104s−1 (for aluminium alloy and 6 ⋅ 103s−1 (for tungsten alloy.

  5. Influences of pulsed current tungsten inert gas welding parameters on the tensile properties of AA 6061 aluminium alloy

    International Nuclear Information System (INIS)

    Senthil Kumar, T.; Balasubramanian, V.; Sanavullah, M.Y.

    2007-01-01

    Medium strength aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. In any structural application of this alloy consideration its weldability is of utmost importance as welding is largely used for joining of structural components. The preferred welding process of aluminium alloy is frequently tungsten inert gas (TIG) welding due to its comparatively easier applicability and better economy. In the case of single pass TIG welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. The use of pulsed current parameters has been found to improve the mechanical properties of the welds compared to those of continuous current welds of this alloy due to grain refinement occurring in the fusion zone. Many considerations come into the picture and one need to carefully balance various pulse current parameters to arrive at an optimum combination. Hence, in this investigation an attempt has been made to study the influence of pulsed current TIG welding parameters on tensile properties of AA 6061 aluminium alloy weldments

  6. Mechanical characterization and modeling of brazed tungsten and Cu-Cr-Zr alloy using stress relief interlayers

    Science.gov (United States)

    Qu, Dandan; Zhou, Zhangjian; Yum, Youngjin; Aktaa, Jarir

    2014-12-01

    A rapidly solidified foil-type Ti-Zr based amorphous filler with a melting temperature of 850 °C was used to braze tungsten to Cu-Cr-Zr alloy for water cooled divertors and plasma facing components application. Brazed joints of dissimilar materials suffer from a mismatch in coefficients of thermal expansion. In order to release the residual stress caused by the mismatch, brazed joints of tungsten and Cu-Cr-Zr alloy using different interlayers were studied. The shear strength tests of brazed W/Cu joints show that the average strength of the joint with a W70Cu30 composite plate interlayer reached 119.8 MPa, and the average strength of the joint with oxygen free high conductivity copper (OFHC Cu)/Mo multi-interlayers reached 140.8 MPa, while the joint without interlayer was only 16.6 MPa. Finite element method (FEM) has been performed to investigate the stress distribution and effect of stress relief interlayers. FEM results show that the maximum von Mises stress occurs in the tungsten/filler interface and that the filler suffers the peak residual stresses and becomes the weakest zone. And the use of OFHC Cu/Mo multi-interlayers can reduce the residual stress significantly, which agrees with the mechanical experiment data.

  7. Mechanical characterization and modeling of brazed tungsten and Cu–Cr–Zr alloy using stress relief interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Dandan, E-mail: dandan.qu@partner.kit.edu [School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Zhou, Zhangjian, E-mail: zhouzhangjianustb@163.com [School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Yum, Youngjin [School of Mechanical Engineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Aktaa, Jarir [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2014-12-15

    A rapidly solidified foil-type Ti–Zr based amorphous filler with a melting temperature of 850 °C was used to braze tungsten to Cu–Cr–Zr alloy for water cooled divertors and plasma facing components application. Brazed joints of dissimilar materials suffer from a mismatch in coefficients of thermal expansion. In order to release the residual stress caused by the mismatch, brazed joints of tungsten and Cu–Cr–Zr alloy using different interlayers were studied. The shear strength tests of brazed W/Cu joints show that the average strength of the joint with a W70Cu30 composite plate interlayer reached 119.8 MPa, and the average strength of the joint with oxygen free high conductivity copper (OFHC Cu)/Mo multi-interlayers reached 140.8 MPa, while the joint without interlayer was only 16.6 MPa. Finite element method (FEM) has been performed to investigate the stress distribution and effect of stress relief interlayers. FEM results show that the maximum von Mises stress occurs in the tungsten/filler interface and that the filler suffers the peak residual stresses and becomes the weakest zone. And the use of OFHC Cu/Mo multi-interlayers can reduce the residual stress significantly, which agrees with the mechanical experiment data.

  8. The effect of low energy helium ion irradiation on tungsten-tantalum (W-Ta) alloys under fusion relevant conditions

    Science.gov (United States)

    Gonderman, S.; Tripathi, J. K.; Novakowski, T. J.; Sizyuk, T.; Hassanein, A.

    2017-08-01

    Currently, tungsten remains the best candidate for plasma-facing components (PFCs) for future fusion devices because of its high melting point, low erosion, and strong mechanical properties. However, continued investigation has shown tungsten to undergo severe morphology changes under fusion-like conditions. These results motivate the study of innovative PFC materials which are resistant to surface morphology evolution. The goal of this work is to examine tungsten-tantalum (W-Ta) alloys, a potential PFC material, and their response to low energy helium ion irradiation. Specifically, W-Ta samples are exposed to 100 eV helium irradiations with a flux of 1.15 × 1021 ions m-2 s-1, at 873 K, 1023 K, and 1173 K for 1 h duration. Scanning electron microscopy (SEM) reveals significant changes in surface deterioration due to helium ion irradiation as a function of both temperature and tantalum concentration in W-Ta samples. X-Ray Diffraction (XRD) studies show a slight lattice parameter expansion in W-Ta alloy samples compared to pure W samples. The observed lattice parameter expansion in W-Ta alloy samples (proportional to increasing Ta wt.% concentrations) reflect significant differences observed in the evolution of surface morphology, i.e., fuzz development processes for both increasing Ta wt.% concentration and target temperature. These results suggest a correlation between the observed morphology differences and the induced crystal structure change caused by the presence of tantalum. Shifts in the XRD peaks before and after 100 eV helium irradiation with a flux of 1.15 × 1021 ions m-2 s-1, 1023 K, for 1 h showed a significant difference in the magnitude of the shift. This has suggested a possible link between the atomic spacing of the material and the accumulated damage. Ongoing research is needed on W-Ta alloys and other innovative materials for their application as irradiation resistant materials in future fusion or irradiation environments.

  9. Tracing Sources and Contamination Assessments of Heavy Metals in Road and Foliar Dusts in a Typical Mining City, China.

    Science.gov (United States)

    Yang, Jie; Teng, Yanguo; Song, Liuting; Zuo, Rui

    2016-01-01

    Road and foliar dust samples from four land-use districts of Panzhihua City, a famous V-Ti magnetite production area of China, were collected to investigate the sources and distribution characteristics of 9 heavy metals (V, Pb, Cd, Cu, Zn, Ni, Cr, Fe, and Mn). The results suggest that foliar samples had smaller particle size and higher heavy metal contents than road dusts. The contamination assessments of heavy metals were as follows: Pb and V (significant enrichment) > Zn, Ni, Cr, Fe, and Mn (moderate enrichment) > Cd and Ni (minimal enrichment). Statistical analyses showed Pb, as the primary pollution element, originated from waste incineration and lead-fuel combustion. The sources of Zn, Ni, Cr, Fe, V, and Mn were fugitive dust and traffic activities. Potential origins of Cu were corrosion of alloys used in vehicle components, vehicle covers, or other metallic surfaces and materials. The sources of Cd were different from any other heavy metals. Traffic and industrial activities were the main anthropogenic origins of heavy metals in dusts of Panzhihua, and more attention should be paid to heavy metal pollution in agricultural area.

  10. Tracing Sources and Contamination Assessments of Heavy Metals in Road and Foliar Dusts in a Typical Mining City, China.

    Directory of Open Access Journals (Sweden)

    Jie Yang

    Full Text Available Road and foliar dust samples from four land-use districts of Panzhihua City, a famous V-Ti magnetite production area of China, were collected to investigate the sources and distribution characteristics of 9 heavy metals (V, Pb, Cd, Cu, Zn, Ni, Cr, Fe, and Mn. The results suggest that foliar samples had smaller particle size and higher heavy metal contents than road dusts. The contamination assessments of heavy metals were as follows: Pb and V (significant enrichment > Zn, Ni, Cr, Fe, and Mn (moderate enrichment > Cd and Ni (minimal enrichment. Statistical analyses showed Pb, as the primary pollution element, originated from waste incineration and lead-fuel combustion. The sources of Zn, Ni, Cr, Fe, V, and Mn were fugitive dust and traffic activities. Potential origins of Cu were corrosion of alloys used in vehicle components, vehicle covers, or other metallic surfaces and materials. The sources of Cd were different from any other heavy metals. Traffic and industrial activities were the main anthropogenic origins of heavy metals in dusts of Panzhihua, and more attention should be paid to heavy metal pollution in agricultural area.

  11. Heavy Metal Contaminated Soil Imitation Biological Treatment Overview

    Science.gov (United States)

    Pan, Chang; Chen, Jun; Wu, Ke; Zhou, Zhongkai; Cheng, Tingting

    2018-01-01

    In this paper, the treatment methods of heavy metal pollution in soils were analyzed, the existence and transformation of heavy metals in soil were explored, and the mechanism of heavy metal absorption by plants was studied. It was concluded that the main form of plants absorb heavy metals in the soil is exchangeable. The main mechanism was that the plant cell wall can form complex with heavy metals, so that heavy metals fixed on the cell wall, and through the selective absorption of plasma membrane into the plant body. In addition, the adsorption mechanism of the adsorbed material was analyzed. According to the results of some researchers, it was found that the mechanism of adsorption of heavy metals was similar to that of plants. According to this, using adsorbent material as the main material, Imitate the principle of plant absorption of heavy metals in the soil to removing heavy metals in the soil at one-time and can be separated from the soil after adsorption to achieve permanent removal of heavy metals in the soil was feasibility.

  12. Advances in Understanding How Heavy Metal Pollution Triggers Gastric Cancer

    Directory of Open Access Journals (Sweden)

    Wenzhen Yuan

    2016-01-01

    Full Text Available With the development of industrialization and urbanization, heavy metals contamination has become a major environmental problem. Numerous investigations have revealed an association between heavy metal exposure and the incidence and mortality of gastric cancer. The mechanisms of heavy metals (lead, cadmium, mercury, chromium, and arsenic contamination leading to gastric cancer are concluded in this review. There are four main potential mechanisms: (1 Heavy metals disrupt the gastric mucosal barrier by decreasing mucosal thickness, mucus content, and basal acid output, thereby affecting the function of E-cadherin and inducing reactive oxygen species (ROS damage. (2 Heavy metals directly or indirectly induce ROS generation and cause gastric mucosal and DNA lesions, which subsequently alter gene regulation, signal transduction, and cell growth, ultimately leading to carcinogenesis. Exposure to heavy metals also enhances gastric cancer cell invasion and metastasis. (3 Heavy metals inhibit DNA damage repair or cause inefficient lesion repair. (4 Heavy metals may induce other gene abnormalities. In addition, heavy metals can induce the expression of proinflammatory chemokine interleukin-8 (IL-8 and microRNAs, which promotes tumorigenesis. The present review is an effort to underline the human health problem caused by heavy metal with recent development in order to garner a broader perspective.

  13. Development of bonding techniques between tungsten and copper alloy for plasma facing components by HIP method (2). Bonding between tungsten and DS-copper

    International Nuclear Information System (INIS)

    Saito, Shigeru; Fukaya, Kiyoshi; Eto, Motokuni; Ishiyama, Shintaro; Akiba, Masato

    2000-02-01

    Recently, W (tungsten)-alloys are considered as plasma facing material (PFM) for ITER because of these many favorable properties such as high melting point (3655 K), relatively high thermal conductivity and higher resistivity for plasma sputtering. On the other hand, Cu-alloys, especially DS (dispersion strengthened)-Cu, are proposed as heat sink materials because of its high thermal conductivity and good mechanical properties at high temperature. Plasma facing components (PFC) are designed as the duplex structure where W armor tiles are bonded with Cu-alloy heat sink. Then, we started the bonding technology development by hot isostatic press (HIP) method to bond W with Cu-alloys because of its many advantages. Until now, it was reported that we could get the best HIP bonding conditions for W and OFHC-Cu and the tensile strength was similar with HIP treated OFHC-Cu. In this experiments, bonding tests of W and DS-Cu with insert material were performed. As insert material, OFHC-Cu was used with different thickness. Bonding conditions were selected as 1273 K x 2 hours x 147 MPa. Bonding tests with 0.3 to 1.8 mm thickness OFHC-Cu were successfully bonded but with 0.1 mm thickness was not bonded. From the results of tensile tests, the tensile strength of the specimens with 0.3 and 0.5 mm thickness were decreased at elevated temperature. It was shown that over 1.0 mm thickness OFHC-Cu insert may be needed and the tensile strength were a little higher than that of HIP treated OFHC-Cu. (author)

  14. Heavy metal burden of the Pinnau river

    International Nuclear Information System (INIS)

    1993-01-01

    The water phase and sediment of the Pinnau river were investigated for their heavy-metal pollution. Tests for the elements chromium, mercury, nickel, arsenic, lead, copper, cadmium, zinc and iron were carried through with sediment samples in 1984 and 1989 and with water samples in 1987 and 1989. Whereas no significant changes in the levels of these metals were found in the water phase during the two-year period of invetigation, slightly reduced levels of zinc, cadmium and mercury were established in the sediment in 1989 as compared to 1984. (orig.) [de

  15. Uranium and heavy metals in phosphate fertilizers

    International Nuclear Information System (INIS)

    Khater, A.E.M.

    2008-01-01

    Agricultural applications of chemical fertilizers are a worldwide practice. The specific activity of uranium-238 and heavy metals in phosphate fertilizers depends on the phosphate ore from which the fertilizer produced and on the chemical processing of the ore. Composite phosphate fertilizers samples where collected and the uranium-238 specific activity, in Bq/kg, and As, Cd, Cu, Pb, Se concentration, in ppm, were measured. The annual addition of these elements in soil due to fertilization were calculated and discussed. (author)(tk)

  16. Evaluation of heavy metal complex phytotoxicity

    Directory of Open Access Journals (Sweden)

    Vita Vasilyevna Datsenko

    2016-07-01

    Full Text Available The experimental data dealing with the effect of heavy metals contained in the technogenic contaminated soils on plant objects under controlled conditions was discussed. The aim of this work is to define the quantitative indicators of copper and zinc potential phytotoxicity, namely germination energy, simultaneous germination and duration of the test plants. It was found that the activity of the test plant growth is linked with copper and zinc complex action. Joint effect of copper and zinc is manifested both in inhibition of lettuce growth and determined, above all, by the nature contamination, soil properties and biological specificity of the test plants.

  17. Heavy Metals Pollution in Lake Mariut

    International Nuclear Information System (INIS)

    Saad, M.A.H.; Ezzat, A.A.E.; El-Rayis, O.A.; Hafez, H.

    1981-01-01

    The occurrence and distribution of heavy metals in the water of the heavily polluted Lake Mariut (Egypt) during August 1978 to September 1979 as well as the accumulation of these metals in the different parts of the common fish, Tilapia species, were studied. The study represents a second part of a pilot project on pollution of Lake Mariut supported by IAEA. The mean concentrations of the measured Zn, Gu, Fe, Mn and Cd in the lake water were 10.9, 4.2, 19.1, 26.2 and 0.62 μg/l, respectively

  18. Health concerns of heavy metals and metalloids.

    Science.gov (United States)

    Cooksey, Chris

    2012-01-01

    There is a long history and an overwhelming amount of data on the toxicity of heavy metal compounds. Here a brief look is taken of some aspects of the toxicity of lead, cadmium, mercury and arsenic, chosen for their historical importance and environmental significance, highlighting especially the contrast between the acute and chronic toxicity of purely inorganic species and their organic derivatives. For further details of other toxic metal compounds, the reader might like to consult "Elements of murder: a history of poison" by John Emsley (2005, Oxford University Press).

  19. Characterization study of heavy metal-bearing phases in MSW slag

    International Nuclear Information System (INIS)

    Saffarzadeh, Amirhomayoun; Shimaoka, Takayuki; Motomura, Yoshinobu; Watanabe, Koichiro

    2009-01-01

    Slag products derived from the pyrolysis/melting and plasma/melting treatment of municipal solid waste (MSW) in Japan were examined for the characterization study of heavy metal-bearing phases using petrographic techniques. Detailed microscopic observations revealed that the shapes of heavy metal-rich inclusions are generally spherical to semi-spherical and their sizes range from submicron to scarcely large size spheres (over 100 μm). The experiments (both optical microscopy and electron probe microanalysis) indicated that Fe and Cu participate in mutual substitution and different proportions, and form mainly two-phase Fe-Cu alloys that bound in the silicate glass. This alloy characterizes the composition of more than 80% of the metal-rich inclusions. Other metals and non-metals (such as Pb, Ni, Sb, Sn, P, Si, Al and S) with variable amounts and uneven distributions are also incorporated in the Fe-Cu alloy. In average, the bulk concentration of heavy metals in samples from pyrolysis/melting type is almost six times greater than samples treated under plasma/arc processing. The observations also confirmed that slag from pyrolysis origin contains remarkably higher concentration of metallic inclusions than slag from plasma treatment. In the latter, the metallic compounds are separately tapped from molten slag during the melting treatment that might lead to the generation of safer slag product for end users from environmental viewpoint.

  20. Electro-deposition metallic tungsten coatings in a Na{sub 2}WO{sub 4}-WO{sub 3} melt on copper based alloy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.H., E-mail: dreamerhong77@126.com [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Zhang, Y.C.; Liu, Q.Z.; Li, X.L.; Jiang, F. [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The tungsten coating (>1 mm) was obtained by electro-deposition method in molten salt. Black-Right-Pointing-Pointer Different thickness tungsten coatings were obtained by using different durations. Black-Right-Pointing-Pointer Good performance of coating was obtained when pulse parameters were modulated. - Abstract: The tungsten coating was prepared by electro-deposition technique on copper alloy substrate in a Na{sub 2}WO{sub 4}-WO{sub 3} melt. The coating's surface and cross-section morphologies as well as its impurities were investigated by XPS, SEM and line analysis. Various plating durations were investigated in order to obtain an optimal coating's thickness. The results demonstrated that the electro-deposited coating was compact, voidless, crackless and free from impurities. The tungsten coating's maximum Vickers hardness was measured to be 520 HV. The tungsten coating's minimum oxygen content was determined to be 0.018 wt%. Its maximum thickness was measured to be 1043.67 {mu}m when the duration of electrolysis was set to 100 h. The result of this study has demonstrated the feasibility of having thicker tungsten coatings on copper alloy substrates. These electrodeposited tungsten coatings can be potentially implemented as reliable armour for the medium heat flux plasma facing component (PFC).

  1. Perilous Effects of Heavy Metals Contamination on Human Health

    Directory of Open Access Journals (Sweden)

    Naseem Zahra

    2017-06-01

    Full Text Available Heavy metals form a versatile group of high density elements that vary considerably in their biological roles and chemical properties. Although many heavy metals are essential trace elements yet they have long been recognized as environmental pollutants due their toxic effects. Increased industrialization, urbanization anthropogenic activities like mining, smelting and other agricultural activities have resulted in accumulation of heavy metals in the environment. Heavy metals such as nickel, cadmium, zinc, copper, mercury, arsenic and chromium are not easily degradable and tend to build up in soil. These heavy metals through various routes such as fish and plants make their way into the human body and are known to have serious detrimental effects on human health at elevated levels. The harmful effects of some important heavy metals on human health have been discussed.

  2. Heavy metal decontamination of sludges and soils. Pt. 2

    International Nuclear Information System (INIS)

    Niemann, J.

    1993-06-01

    This research project deals with decontamination technology for contaminated soil and sediments. A pilot plant for the decontamination of soil contaminated with heavy metals has been erected and is operated. The process is arranged in two steps: - heavy metal contaminated solid is decontaminted with acidic extraction. - the heavy metals are separated in a recyclable formation from the process solution you gain in the first process step. Heavy metal contaminated soil, heavy metal contaminated sediments (habour sediments) as well as residue from a soil regeneration plant have been successfully decontaminated in the pilot plan. An adaption of the process is necessary for various materials. High rates of mobilisation of heavy metals (e.g. lead, cadmium, chromium, copper, nickel, zinc) were obtained, especially with soil which contains less organic matter. (orig.). 54 figs., 30 tabs., 45 refs [de

  3. Heavy metal ions are potent inhibitors of protein folding

    International Nuclear Information System (INIS)

    Sharma, Sandeep K.; Goloubinoff, Pierre; Christen, Philipp

    2008-01-01

    Environmental and occupational exposure to heavy metals such as cadmium, mercury and lead results in severe health hazards including prenatal and developmental defects. The deleterious effects of heavy metal ions have hitherto been attributed to their interactions with specific, particularly susceptible native proteins. Here, we report an as yet undescribed mode of heavy metal toxicity. Cd 2+ , Hg 2+ and Pb 2+ proved to inhibit very efficiently the spontaneous refolding of chemically denatured proteins by forming high-affinity multidentate complexes with thiol and other functional groups (IC 50 in the nanomolar range). With similar efficacy, the heavy metal ions inhibited the chaperone-assisted refolding of chemically denatured and heat-denatured proteins. Thus, the toxic effects of heavy metal ions may result as well from their interaction with the more readily accessible functional groups of proteins in nascent and other non-native form. The toxic scope of heavy metals seems to be substantially larger than assumed so far

  4. A review of phytoremediation technology: heavy metals uptake by plants

    Science.gov (United States)

    Sumiahadi, A.; Acar, R.

    2018-03-01

    Heavy metal is one of the serious environmental pollutions for now days as impact of industrial development in several countries. Heavy metals give toxic effects on human health and cause several serious diseases. Several techniques have been using for removing heavy metal contaminants from the environmental but these techniques have limitations such as high cost, long time, logistical problems and mechanical complexity. Phytoremediation can be used as an alternative solution for heavy metal remediation process because of its advantages as a cost-effective, efficient, environment- and eco-friendly technology based on the use of metal-accumulating plants. According to previous studies, several plants have a high potential as heavy metals bioaccumulator and can be used for phytoremediation process of heavy metals.

  5. Atmospheric heavy metal deposition in Europe estimated by moss analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruehling, Aa. [Swedish Environmental Research Inst., Lund (Sweden). Dept. of Ecology

    1995-12-31

    Atmospheric heavy metal deposition in Europe including 21 countries was monitored in 1990-1992 by the moss technique. This technique is based on the fact that the concentrations of heavy metals in moss are closely correlated to atmospheric deposition. This was the first attempt to map heavy metal deposition in this large area. The objectives of the project were to characterise qualitatively and quantitatively the regional atmospheric deposition pattern of heavy metals in background areas in Europe, to indicate the location of important heavy metal pollution sources and to allow retrospective comparisons with similar studies. The present survey is a follow-up of a joint Danish and Swedish project in 1980 and an extended survey in 1985 within the framework of the Nordic Council of Ministers. In Sweden, heavy-metal deposition was first mapped on a nation-wide scale in 1968-1971 and 1975. (author)

  6. Atmospheric heavy metal deposition in Europe estimated by moss analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruehling, Aa [Swedish Environmental Research Inst., Lund (Sweden). Dept. of Ecology

    1996-12-31

    Atmospheric heavy metal deposition in Europe including 21 countries was monitored in 1990-1992 by the moss technique. This technique is based on the fact that the concentrations of heavy metals in moss are closely correlated to atmospheric deposition. This was the first attempt to map heavy metal deposition in this large area. The objectives of the project were to characterise qualitatively and quantitatively the regional atmospheric deposition pattern of heavy metals in background areas in Europe, to indicate the location of important heavy metal pollution sources and to allow retrospective comparisons with similar studies. The present survey is a follow-up of a joint Danish and Swedish project in 1980 and an extended survey in 1985 within the framework of the Nordic Council of Ministers. In Sweden, heavy-metal deposition was first mapped on a nation-wide scale in 1968-1971 and 1975. (author)

  7. Distribution of heavy metals in Tamshui mangrove forest ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, C Y; Chou, C H

    1990-06-01

    Tamsui estuary area is one of the few places in Taiwan where mangrove is still growing. Heavy metals, carried by the water of the Tamsui river, are accumulated in the estuary soil. Most heavy metals in soil, however, are immobile under reducing conditions and are fixed in the large amount of organic matter present. Heavy metals are distributed at different concentrations in various tissues of Kandelia candel as well as grasses of Phragmites communis, Imperata cylindrica, and Cyperus malaccensis growing in the swamp area. The concentration of heavy metals was significantly higher root than in stems and leaves. The absorption of heavy metals by the plants was less in soil that was frequently submerged. Kandelia candel seems to have no special tolerance to copper and zinc. The soil environment which favors reduced availability of heavy metals may help Kandelia candel adapt to growth in the polluted estuary.

  8. Effect of heavy metal and EDTA application on heavy metal uptake ...

    African Journals Online (AJOL)

    Yomi

    2012-04-12

    Apr 12, 2012 ... Cadmium, lead and ... removal of Cd, Cr, Cu, Ni, Pb, and Zn (Prasad and ... collected for the analysis of heavy metal concentrations of Cd, Cr ... One hundred millgram (100 mg) of leaf tissues ..... Variability for the fatty acid.

  9. Development of bonding techniques between tungsten and copper alloy for plasma facing components by HIP method. 1. Bonding between tungsten and oxygen free copper

    International Nuclear Information System (INIS)

    Saito, Shigeru; Fukaya, Kiyoshi; Ishiyama, Shintaro; Eto, Motokuni; Akiba, Masato

    1999-08-01

    In recent years, it has been considered that W (tungsten) is one of candidate materials for armor tiles of plasma facing components, like first wall or divertor, of fusion reactor. On the other hand, oxygen free high thermal conductivity (OFHC)-copper is proposed as heat sink materials behind the plasma facing materials because of its high thermal conductivity. However, plasma facing components are exposed to cyclic high heat load and heavily irradiated by 14 MeV neutron. Under these conditions, many unfavorable effects, for instance, thermal stresses of bonding interface, irradiation damage and He atom production by nuclear transmutation, will be decreased bonding strength between W and Cu alloys. Therefore, it is necessary to develop a reliable bonding techniques in order to make plasma facing components which can resist them. Then, we started the bonding technology development by hot isostatic press (HIP) method to bond W with Cu alloys. In this experiments, to optimize HIP bonding conditions, four point bending were performed for each bonded conditions at temperature from R.T. to 873 K and we could get the best HIP bonding conditions for W and OFHC-Cu as 1273 K x 2 hours x 147 MPa. To evaluate bonding strength of the specimen bonded at these conditions, tensile tests were also performed at same temperature range. The tensile strength was similar with OFHC-Cu which were treated at same conditions. (author)

  10. Characteristics of heavy metal pollution on roadside soil along highway

    Science.gov (United States)

    Zheng, Chaocheng

    2017-10-01

    Highway traffic is the main source of heavy metal pollution. Due to limited cropland, it is very common to plant crops along the highways. So, in view of agricultural products safety, heavy metal pollution by highway traffic to soils along highway is widely concerned. Therefore, to study distribution traits, accumulative laws and influence factors of heavy metals in agricultural soils could provide scientific evidence and theoretical basis for environmental protection along express way.

  11. Performance of Raphidocelis subcapitata exposed to heavy metal mixtures.

    Science.gov (United States)

    Expósito, Nora; Kumar, Vikas; Sierra, Jordi; Schuhmacher, Marta; Giménez Papiol, Gemma

    2017-12-01

    Microalgae growth inhibition assays are candidates for referent ecotoxicological assays, and are a fundamental part in the strategy to reduce the use of fish and other animal models in aquatic toxicology. In the present work, the performance of Raphidocelis subcapitata exposed to heavy metals following standardized growth inhibition assays has been assessed in three different scenarios: 1) dilutions of single heavy metals, 2) artificial mixture of heavy metals at similar levels than those found in natural rivers and, 3) natural samples containing known mixtures of contaminants (heavy metals). Chemical speciation of heavy metals has been estimated with Eh-pH diagram and Visual MINTEQ software; heavy metal and free heavy metal ion concentrations were used as input data, together with microalgae growth inhibition, for Dr. Fit software. The final goal was to assess the suitability of the ecotoxicological test based on the growth inhibition of microalgae cultures, and the mathematic models based on these results, for regulatory and decision-making purposes. The toxicity of a given heavy metal is not only determined by its chemical speciation; other chemical and biological interaction play an important role in the final toxicity. Raphidocelis subcapitata 48h-h-EC50 for tested heavy metals (especially Cu and Zn) were in agreement with previous studies, when ion metal bioavailability was assumed to be 100%. Nevertheless, the calculated growth inhibition was not in agreement with the obtained inhibition when exposed to the artificial mixture of heavy metals or the natural sample. Interactions between heavy metal ions and the compounds of the culture media and/or the natural sample determine heavy metal bioavailability, and eventually their toxicity. More research is needed for facing the challenge posed by pollutant mixtures as they are present in natural environments, and make microalgae-based assays suitable for pollution management and regulatory purposes. Copyright

  12. Effects of heavy metal adsorption on silicene

    KAUST Repository

    Kaloni, Thaneshwor P.

    2014-06-02

    Based on first-principles calculations, we study the effects of heavy metal atoms (Au, Hg, Tl, and Pb) adsorbed on silicene. We find that the hollow site is energetically favorable in each case. We particulary address the question how the adsorption modifies the band structure in the vicinity of the Fermi energy. Our results demonstrate that the heavy metal adatoms result in substantial energy gaps and band splittings in the silicene sheet as long as the binding is strong, which, however, is not always the case. (© 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim) Carbon nanotube flexible sponge was manufactured as high performance electromagnetic shielding material. Chemical vapour deposition (CVD) synthesized sponges with extreme light weight show an electromagnetic shielding above 20 dB and a specific electromagnetic shielding as high as 1100 dB cm3g-1 in the whole 1-18 GHz range. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Sediment, water pollution indicators for heavy metals

    International Nuclear Information System (INIS)

    Cabaleiro, S.; Horn, A.

    2010-01-01

    The complexity of an aquatic system requires consideration of its dynamics: spatial and temporal variations of physical, chemical and biological. Heavy metals have peculiar behavior in the aquatic system and may not be available in the waters, but on sediments.The sub-basin of the Sarandi stream is responsible for the contamination of Pampulha Lake. The Instituto Mineiro das Águas – IGAM - uses tool for monitoring the quality of surface water for developing strategies for conservation, restoration and rational use of water resources. So through the indices: IQA ( Indice de qualidade de águas) Index of water quality, and TC- toxic contamination, reduces conflicts, implements the disciplining of the environmental economy.This study determined the monitoring of sediment and water of Sarandi Stream, so in the samples collected during dry and rainy seasons (2007- 2008) were analyzed heavy metals (Cu, Cd, Cr, Co, Ni, Zn, Pb) and physical-chemical factors (conductivity, solids dissolved, temperature, turbidity). This allowed the determination of Hackanson factors of contamination and Muller Index geoaccumulation, indicating very high contamination in sediments regarding the elements Cr, Cu, and Cd, and high contamination for Pb, Zn, and Mn. The comparison with the indices of water quality- IQA (IGAM - 2006, 2007 and 2008), combined with exploratory data analysis and graphs of correlation between the variables indicated favorable conditions for metals contamination on water and sediment for these metals, besides allowing the identification of its source

  14. Solubility of heavy metals added to MSW

    International Nuclear Information System (INIS)

    Lo, H.M.; Lin, K.C.; Liu, M.H.; Pai, T.Z.; Lin, C.Y.; Liu, W.F.; Fang, G.C.; Lu, C.; Chiang, C.F.; Wang, S.C.; Chen, P.H.; Chen, J.K.; Chiu, H.Y.; Wu, K.C.

    2009-01-01

    This paper aims to investigate the six heavy metal levels (Cd, Cr, Cu, Pb, Ni and Zn) in municipal solid waste (MSW) at different pHs. It intends to provide the baseline information of metals solubility in MSW co-disposed or co-digested with MSW incinerator ashes in landfill or anaerobic bioreactors or heavy metals contaminated in anaerobic digesters. One milliliter (equal to 1 mg) of each metal was added to the 100 ml MSW and the batch reactor test was carried out. The results showed that higher HNO 3 and NaOH were consumed at extreme pH of 1 and 13 compared to those from pH 2 to 11 due to the comparably higher buffer capacity. Pb was found to have the least soluble level, highest metal adsorption (%) and highest partitioning K d (l g -1 ) between pH 3 and 12. In contrast, Ni showed the highest soluble level, lowest metal adsorption (%) and lowest K d (l g -1 ) between pH 4 and 12. Except Ni and Cr, other four metals seemed to show the amphibious properties as comparative higher solubility was found in the acidic and basic conditions

  15. Solubility of heavy metals added to MSW

    Energy Technology Data Exchange (ETDEWEB)

    Lo, H.M. [Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Gifong E. Road, Wufong, Taichung County 41349, Taiwan (China)], E-mail: hmlo@cyut.edu.tw; Lin, K.C. [Department of Occupational Safety and Health, Chung Shan Medical University, 110, Sec. 1, Jiangguo N. Rd., Taichung 402, Taiwan (China); Liu, M.H.; Pai, T.Z. [Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Gifong E. Road, Wufong, Taichung County 41349, Taiwan (China); Lin, C.Y. [Department of Soil and Water Conservation, Chung Hsing University, 250 Kuokuang Road, Taichung 402, Taiwan (China); Liu, W.F. [Department of Electronical Engineering, Feng Chia University, 100 Wenhwa Road, Taichung 407, Taiwan (China); Fang, G.C. [Department of Environmental Engineering, Hungkuang University, 34 Chung-Chie Road, Sha Lu, Taichung 433, Taiwan (China); Lu, C. [Department of Environmental Engineering, Chung Hsing University, 250 Kuokuang Road, Taichung 402, Taiwan (China); Chiang, C.F. [Department of Health Risk Management, China Medical University, No. 91 Hsueh-Shih Road, Taichung 40402, Taiwan (China); Wang, S.C.; Chen, P.H.; Chen, J.K.; Chiu, H.Y.; Wu, K.C. [Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Gifong E. Road, Wufong, Taichung County 41349, Taiwan (China)

    2009-01-15

    This paper aims to investigate the six heavy metal levels (Cd, Cr, Cu, Pb, Ni and Zn) in municipal solid waste (MSW) at different pHs. It intends to provide the baseline information of metals solubility in MSW co-disposed or co-digested with MSW incinerator ashes in landfill or anaerobic bioreactors or heavy metals contaminated in anaerobic digesters. One milliliter (equal to 1 mg) of each metal was added to the 100 ml MSW and the batch reactor test was carried out. The results showed that higher HNO{sub 3} and NaOH were consumed at extreme pH of 1 and 13 compared to those from pH 2 to 11 due to the comparably higher buffer capacity. Pb was found to have the least soluble level, highest metal adsorption (%) and highest partitioning K{sub d} (l g{sup -1}) between pH 3 and 12. In contrast, Ni showed the highest soluble level, lowest metal adsorption (%) and lowest K{sub d} (l g{sup -1}) between pH 4 and 12. Except Ni and Cr, other four metals seemed to show the amphibious properties as comparative higher solubility was found in the acidic and basic conditions.

  16. Synthetic biology for microbial heavy metal biosensors.

    Science.gov (United States)

    Kim, Hyun Ju; Jeong, Haeyoung; Lee, Sang Jun

    2018-02-01

    Using recombinant DNA technology, various whole-cell biosensors have been developed for detection of environmental pollutants, including heavy metal ions. Whole-cell biosensors have several advantages: easy and inexpensive cultivation, multiple assays, and no requirement of any special techniques for analysis. In the era of synthetic biology, cutting-edge DNA sequencing and gene synthesis technologies have accelerated the development of cell-based biosensors. Here, we summarize current technological advances in whole-cell heavy metal biosensors, including the synthetic biological components (bioparts), sensing and reporter modules, genetic circuits, and chassis cells. We discuss several opportunities for improvement of synthetic cell-based biosensors. First, new functional modules must be discovered in genome databases, and this knowledge must be used to upgrade specific bioparts through molecular engineering. Second, modules must be assembled into functional biosystems in chassis cells. Third, heterogeneity of individual cells in the microbial population must be eliminated. In the perspectives, the development of whole-cell biosensors is also discussed in the aspects of cultivation methods and synthetic cells.

  17. Phytoremediation of Heavy Metals in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Felix Aibuedefe AISIEN

    2010-12-01

    Full Text Available One of the major environmental problems is the pollution of water and soil by toxic heavy metals. This study investigated the phytoremediation potential of water hyacinth, for the removal of cadmium (Cd, lead (Pb and zinc (Zn. Water hyacinths were cultured in bore-hole water, supplemented with 5mg/l of Zn and Pb and 1mg/l of Cd at pH 4.5, 6.8 and 8.5. The plants were separately harvested each week for six weeks. The results showed that removal of these metals from solution was fast especially in the first two weeks, after which it became gradual till saturation point was reached. The accumulation of Cd and Zn in leaves and roots increased with increase in pH. The highest accumulation was in the roots with metal concentration of 4870mg/kg, 4150mg/kg and 710mg/kg for Zn, Pb and Cd respectively at pH 8.5. The maximum values of bioconcentration factor (BCF for Zn, Pb and Cd were 1674, 1531 and 1479 respectively, suggesting that water hyacinth was good accumulator of Zn, Pb and Cd, and could be used to treat industrial wastewater contaminated with heavy metals such as Zn, Pb and Cd.

  18. Approaches for enhanced phytoextraction of heavy metals.

    Science.gov (United States)

    Bhargava, Atul; Carmona, Francisco F; Bhargava, Meenakshi; Srivastava, Shilpi

    2012-08-30

    The contamination of the environment with toxic metals has become a worldwide problem. Metal toxicity affects crop yields, soil biomass and fertility. Soils polluted with heavy metals pose a serious health hazard to humans as well as plants and animals, and often requires soil remediation practices. Phytoextraction refers to the uptake of contaminants from soil or water by plant roots and their translocation to any harvestable plant part. Phytoextraction has the potential to remove contaminants and promote long-term cleanup of soil or wastewater. The success of phytoextraction as a potential environmental cleanup technology depends on factors like metal availability for uptake, as well as plants ability to absorb and accumulate metals in aerial parts. Efforts are ongoing to understand the genetics and biochemistry of metal uptake, transport and storage in hyperaccumulator plants so as to be able to develop transgenic plants with improved phytoremediation capability. Many plant species are being investigated to determine their usefulness for phytoextraction, especially high biomass crops. The present review aims to give an updated version of information available with respect to metal tolerance and accumulation mechanisms in plants, as well as on the environmental and genetic factors affecting heavy metal uptake. The genetic tools of classical breeding and genetic engineering have opened the door to creation of 'remediation' cultivars. An overview is presented on the possible strategies for developing novel genotypes with increased metal accumulation and tolerance to toxicity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Heavy metals in atmospheric surrogate dry deposition

    Science.gov (United States)

    Morselli; Cecchini; Grandi; Iannuccilli; Barilli; Olivieri

    1999-02-01

    This paper describes a methodological approach for the assessment of the amount of surrogate dry deposition of several toxic heavy metals (Cd, Cr, Cu, Ni, Pb, V, Zn) associated with atmospheric particulate matter at ground level. The objectives of the study were twofold: i) the evaluation of several techniques for the digestion of dry deposition samples for trace metal analysis; ii) the comparison of the results from two samplers with different collecting surfaces. A dry solid surface sampler (DRY sampler, Andersen--USA) and a water layer surface sampler (DAS sampler--MTX Italy) were employed. The samples were collected over a one-year period in an urban site of Bologna (northern Italy). A description is given of the complete procedure, from sampling to data elaboration, including sample storage, digestion and analytical methods. According to the results obtained with three different digestion techniques (Teflon bomb, microwave digester and Teflon flask with vapour cooling system), the highest recovery rate was achieved by the Teflon bomb procedure employing an NBS 1648 Standard Reference Material; 90-95% of the elements considered were recovered by dissolution in a pressurized Teflon bomb with an HNO3-HF mixture. Given these results, the technique was adopted for dry deposition sample digestion. On the basis of the amount of heavy metals measured as monthly deposition fluxes (microg/m2), the collecting efficiency of the DAS sampler for a number of elements was found to be as much as two to three times greater than that of the DRY sampler.

  20. Facultative hyperaccumulation of heavy metals and metalloids.

    Science.gov (United States)

    Pollard, A Joseph; Reeves, Roger D; Baker, Alan J M

    2014-03-01

    Approximately 500 species of plants are known to hyperaccumulate heavy metals and metalloids. The majority are obligate metallophytes, species that are restricted to metalliferous soils. However, a smaller but increasing list of plants are "facultative hyperaccumulators" that hyperaccumulate heavy metals when occurring on metalliferous soils, yet also occur commonly on normal, non-metalliferous soils. This paper reviews the biology of facultative hyperaccumulators and the opportunities they provide for ecological and evolutionary research. The existence of facultative hyperaccumulator populations across a wide edaphic range allows intraspecific comparisons of tolerance and uptake physiology. This approach has been used to study zinc and cadmium hyperaccumulation by Noccaea (Thlaspi) caerulescens and Arabidopsis halleri, and it will be instructive to make similar comparisons on species that are distributed even more abundantly on normal soil. Over 90% of known hyperaccumulators occur on serpentine (ultramafic) soil and accumulate nickel, yet there have paradoxically been few experimental studies of facultative nickel hyperaccumulation. Several hypotheses suggested to explain the evolution of hyperaccumulation seem unlikely when most populations of a species occur on normal soil, where plants cannot hyperaccumulate due to low metal availability. In such species, it may be that hyperaccumulation is an ancestral phylogenetic trait or an anomalous manifestation of physiological mechanisms evolved on normal soils, and may or may not have direct adaptive benefits. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  1. Metallurgical characterization of pulsed current gas tungsten arc, friction stir and laser beam welded AZ31B magnesium alloy joints

    International Nuclear Information System (INIS)

    Padmanaban, G.; Balasubramanian, V.

    2011-01-01

    This paper reports the influences of welding processes such as friction stir welding (FSW), laser beam welding (LBW) and pulsed current gas tungsten arc welding (PCGTAW) on mechanical and metallurgical properties of AZ31B magnesium alloy. Optical microscopy, scanning electron microscopy, transmission electron microscopy and X-Ray diffraction technique were used to evaluate the metallurgical characteristics of welded joints. LBW joints exhibited superior tensile properties compared to FSW and PCGTAW joints due to the formation of finer grains in weld region, higher fusion zone hardness, the absence of heat affected zone, presence of uniformly distributed finer precipitates in weld region.

  2. Adsorption of heavy metal in freeway by asphalt block

    Science.gov (United States)

    Zheng, Chaocheng

    2017-08-01

    Heavy metals are toxic, persistent, and carcinogenic in freeway. Various techniques are available for the removal of heavy metals from waste water among soils during freeway including ion-exchange, membrane filtration, electrolysis, coagulation, flotation, and adsorption. Among them, bio-sorption processes are widely used for heavy metal and other pollutant removal due to its sustainable, rapid and economic. In this paper, heavy metal removal facilitated by adsorption in plants during freeway was illustrated to provide concise information on exploring the adsorption efficiency.

  3. Heavy metals in the cell nucleus - role in pathogenesis.

    Science.gov (United States)

    Sas-Nowosielska, Hanna; Pawlas, Natalia

    2015-01-01

    People are exposed to heavy metals both in an occupational and natural environment. The most pronounced effects of heavy metals result from their interaction with cellular genetic material packed in form of chromatin. Heavy metals influence chromatin, mimicking and substituting natural microelements in various processes taking place in the cell, or interacting chemically with nuclear components: nucleic acids, proteins and lipids. This paper is a review of current knowledge on the effects of heavy metals on chromatin, exerted at the level of various nuclear components.

  4. Remediation of biochar on heavy metal polluted soils

    Science.gov (United States)

    Wang, Shuguang; Xu, Yan; Norbu, Namkha; Wang, Zhan

    2018-01-01

    Unreasonable mining and smelting of mineral resources, solid waste disposal, sewage irrigation, utilization of pesticides and fertilizers would result in a large number of heavy metal pollutants into the water and soil environment, causing serious damage to public health and ecological safety. In recent years, a majority of scholars tried to use biochar to absorb heavy metal pollutants, which has some advantages of extensive raw material sources, low-cost and high environmental stability. This paper reviewed the definition, properties of biochar, the mechanism of heavy metal sorption by biochar and some related problems and prospects, to provide some technical support for the application of biochar into heavy metal polluted soils.

  5. THE HEAVY METALS CONNTENT IN VEGETABLES FROM MIDDLE SPIŠ AREA

    OpenAIRE

    Marek Slávik,Tomáš Tóth; Július Árvay; Miriama Kopernická; Luboš Harangozo; Radovan Stanovič; Pavol Trebichalský; Petra Kavalcová

    2014-01-01

    In the middle area of Spiš, it is significantly burden by heavy metals what is documented by radical content of Hg in soil from Rudňany 58.583645 mg.kg -1. On the content of heavy metals in vegetables grown in this soil it has the same effect. 61.5% samples exceeded the limit value of heavy metals. The most dangerous vegetables were Lactuca sativa L. The limit value was exceed in all determine heavy metals - Hg, Cd, Pb and Cu in this vegetables. In the case of Hg, the limit value exceed 93.86...

  6. Improved inventory for heavy metal emissions from stationary combustion plants

    DEFF Research Database (Denmark)

    Nielsen, Malene; Nielsen, Ole-Kenneth; Hoffmann, Leif

    On behalf of the Ministry of the Environment DCE at Aarhus University annually reports heavy metals (HM) emissions to the UNECE CLRTAP (United Nations Economic Commission for Europe Convention on Long-Range Transboundary Air Pollution). This report presents updated heavy metal emission factors......-2009. The report also include methodology, references and an uncertainty estimate. In Denmark, stationary combustion plants are among the most important emission sources for heavy metals. Emissions of all heavy metals have decreased considerably (73 % - 92 %) since 1990. The main HM emission sources are coal...

  7. Bioremediation of Toxic Heavy Metals: A Patent Review.

    Science.gov (United States)

    Verma, Neelam; Sharma, Rajni

    2017-01-01

    The global industrialization is fulfilling the demands of modern population at the cost of environmental exposure to various contaminants including heavy metals. These heavy metals affect water and soil quality. Moreover, these enter into the food chain and exhibit their lethal effects on the human health even when present at slightly higher concentration than required for normal metabolism. To the worst of their part, the heavy metals may become carcinogenic. Henceforth, the efficient removal of heavy metals is the demand of sustainable development. Remedy: Bioremediation is the 'green' imperative technique for the heavy metal removal without creating secondary metabolites in the ecosystem. The metabolic potential of several bacterial, algal, fungal as well as plant species has the efficiency to exterminate the heavy metals from the contaminated sites. Different strategies like bioaccumulation, biosorption, biotransformation, rhizofilteration, bioextraction and volatilization are employed for removal of heavy metals by the biological species. Bioremediation approach is presenting a splendid alternate for conventional expensive and inefficient methods for the heavy metal removal. The patents granted on the bioremediation of toxic heavy metals are summarized in the present manuscript which supported the applicability of bioremediation technique at commercial scale. However, the implementation of the present information and advanced research are mandatory to further explore the concealed potential of biological species to resume the originality of the environment. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. Evaluation of mechanically alloyed Cu-based powders as filler alloy for brazing tungsten to a reduced activation ferritic-martensitic steel

    Science.gov (United States)

    de Prado, J.; Sánchez, M.; Ureña, A.

    2017-07-01

    80Cu-20Ti powders were evaluated for their use as filler alloy for high temperature brazing of tungsten to a reduced activation ferritic/martensitic steel (Eurofer), and its application for the first wall of the DEMO fusion reactor. The use of alloyed powders has not been widely considered for brazing purposes and could improve the operational brazeability of the studied system due to its narrower melting range, determined by DTA analysis, which enhances the spreading capabilities of the filler. Ti contained in the filler composition acts as an activator element, reacting and forming several interfacial layers at the Eurofer-braze, which enhances the wettability properties and chemical interaction at the brazing interface. Brazing thermal cycle also activated the diffusion phenomena, which mainly affected to the Eurofer alloying elements causing in it a softening band of approximately 400 μm of thickness. However, this softening effect did not degrade the shear strength of the brazed joints (94 ± 23 MPa), because failure during testing was always located at the tungsten-braze interface.

  9. Heavy metal contamination in the vicinity of an industrial area near Bucharest.

    Science.gov (United States)

    Velea, Teodor; Gherghe, Liliana; Predica, Vasile; Krebs, Rolf

    2009-08-01

    Heavy metals such as lead are well known to cause harmful health effects. Especially children are particularly susceptible to increased levels of lead in their blood. It is also a fact that lead concentration is increasing in the environment due to increased anthropogenic activity. The risk of heavy metal contamination is pronounced in the environment adjacent to large industrial complexes. In a combined case study, the environmental pollution by heavy metals was related to children's health in the vicinity of an industrial area located 4 km south-east from Bucharest about 2 km east from the nearest town-Pantelimon. This site includes companies processing different, nonferrous solid wastes for recovery of heavy metals and producing different nonferrous alloys and lead batteries. In this paper, mainly the results of environmental sampling and analyses are summarized. Water, soil, and atmospheric deposition samples were collected from different locations within 3 km from the industrial area. For comparison, samples were also taken from Bucharest. Water samples were filtered (open collecting pots were used on nine different sites between August and November 2006. At most sampling locations, the heavy metal concentrations in soil decrease with increasing distance to the presumably major source of pollution. Highest heavy metal concentrations were found in 10-20 cm soil depths. There were also decreasing heavy metal concentrations for atmospheric deposition with increasing distance to the industrial site. In surface and groundwater samples, traces of zinc, copper and lead were detected. The heavy metal concentrations in soil were increased in the study area, mostly under legal action limits in low-concern areas (e.g., 1,000 mg Pb/kg dry soil), but often above action limits for high-concern areas (100 mg Pb/kg dry soil) such as populated areas. The soluble lead concentrations in water samples indicate a need for monitoring and assessing water quality in more detail. The

  10. An in-situ field ion microscope study of irradiated tungsten and tungsten alloys. II. The recovery behavior in Stages I and II: experimental results. Report No. 2347

    International Nuclear Information System (INIS)

    Wilson, K.L.; Seidman, D.N.

    1974-12-01

    The low temperature FIM isochronal annealing spectrum of four different purity levels of tungsten (resistivity ratios R of 5 . 10 4 , 1.5 . 10 4 , 50 and 15), irradiated in-situ with 30 keV W + ions to a dose of 5 . 10 12 ion cm -2 at 18 K, consisted of distinct recovery peaks at approximately 38, 50, 65 and 80 K with a small amount of recovery observed up to 120 K. The spectra were essentially identical between 18 and 120 K, but a fifth group of W specimens with approximately equal to 5 began to exhibit some deviations from the standard spectrum. This result indicates that the distribution of self-interstitial atoms (SIAs) produced by the ion irradiations in the W FIM tips was such that the SIA-SIA reaction dominated the recovery behavior. The isochronal peak width at half-maximum for the 38 K long-range SIA migration peak and the Stage II peaks in pure W were shown to be approximately equal to the value predicted by a diffusion model. The isochronal recovery spectra for W--0.5 at. per cent and 3 at. per cent Re alloys were radically different from the isochronal recovery spectra of pure W. For both W--Re alloys, the amount of recovery for the long-range migration peak was suppressed, and, for the 3 at. per cent Re alloy, it was almost eliminated. High-purity W (R = 5 . 10 4 ), doped with 50-100 appm carbon, showed a 20 per cent reduction in the amount of recovery observed for the long-range migration peak at 38 K. (U.S.)

  11. The effects of ion irradiation on the micromechanical fracture strength and hardness of a self-passivating tungsten alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lessmann, Moritz T., E-mail: mor.lessmann@gmail.com [School of Mechanical Aerospace and Civil Engineering, The University of Manchester, Manchester (United Kingdom); CCFE, Culham Science Centre, Abingdon (United Kingdom); Sudić, Ivan; Fazinić, Stjepko; Tadić, Tonči [Rudjer Bošković Institute, Bijenička cesta 54, 10000 Zagreb (Croatia); Calvo, Aida [Ceit-IK4 and Tecnun (University of Navarra), San Sebastian (Spain); Hardie, Christopher D.; Porton, Michael [CCFE, Culham Science Centre, Abingdon (United Kingdom); García-Rosales, Carmen [Ceit-IK4 and Tecnun (University of Navarra), San Sebastian (Spain); Mummery, Paul M. [School of Mechanical Aerospace and Civil Engineering, The University of Manchester, Manchester (United Kingdom)

    2017-04-01

    An ultra-fine grained self-passivating tungsten alloy (W88-Cr10-Ti2 in wt.%) has been implanted with iodine ions to average doses of 0.7 and 7 dpa, as well as with helium ions to an average concentration of 650 appm. Pile-up corrected Berkovich nanoindentation reveals significant irradiation hardening, with a maximum hardening of 1.9 GPa (17.5%) observed. The brittle fracture strength of the material in all implantation conditions was measured through un-notched cantilever bending at the microscopic scale. All cantilever beams failed catastrophically in an intergranular fashion. A statistically confirmed small decrease in strength is observed after low dose implantation (−6%), whilst the high dose implantation results in a significant increase in fracture strength (+9%), further increased by additional helium implantation (+16%). The use of iodine ions as the implantation ion type is justified through a comparison of the hardening behaviour of pure tungsten under tungsten and iodine implantation.

  12. Heavy Metals Phytoextraction from the Polluted Soils of Zakamensk (Russia)

    Science.gov (United States)

    Ubugunov, V.; Dorzhonova, V.; Ubugunov, L.

    2012-04-01

    Mining and ore-dressing are one of the most serious causes of environment pollution. Last century in days of active industrialization in Russia a considerable quantity of mineral deposits has been developed. It was not given sufficient attention for ecological safety at that time. After an economic crisis connected with disorder of the USSR and a planned economy, a number of the enterprises became bankrupts and have stopped the activity. As a result the broken landscapes have not been recultivated everywhere, there were numerous wastes. The negative consequences were especially strongly manifested in areas with severe climatic conditions where environmental self-renewal occurred is slowed rather down. The degree of a waste toxicity also acted as the important factor. One of such situations has arisen in Zakamensk - an administrative center of Zakamensky area of Buryat Republic (Russia). Environmental problems of the town have arisen in connection with activity of town-forming enterprise - Dzhidinsky tungsten-molybdenum industrial complex. The enterprise has been organized in 1934 and functioned within 63 years till 1997. During enterprise operating time 3 deposits have been exploited and is created 2 large (more than 40 million tons) tails depository of technogenic sands (TS), located in immediate proximity (less than 1-2 km) from a town residential zone.Sand of tails are rather toxic, the average maintenance of heavy metals in them is (mg/kg): Cd - 42, Pb - 7500, Zn - 3160, Cu - 620, Ni - 34, Co - 44, Mn - 121, Cr - 70, Hg - 0,01, As - 13, Mo - 90. Due to the lack of knowledges on the toxicity of TS in the past century, they were actively used in the road and house construction, during the erection of dams. After scientific studies they were recommended for using as fertilizers. Besides anthropogenic sands movement, there was intensive dispersion of sand by means of water and wind erosion. As a result of natural migration sands got to the subordinated elements of

  13. Penetrating performance and “self-sharpening” behavior of fine-grained tungsten heavy alloy rod penetrators

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Rongmei, E-mail: luorm_1999@126.com [School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu (China); College of Equipment Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning (China); Huang, Dewu; Yang, Mingchuan; Tang, Enling; Wang, Meng; He, Liping [College of Equipment Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning (China)

    2016-10-15

    Rod penetrators with 95W–3.75Ni–1.25Fe fine-grained tungsten heavy alloy (fine-grained 95W) and conventional tungsten heavy alloy rod penetrators with the same chemical composition (conventional 95W) were subjected to ballistic impact to compare their penetration performance. “Self-sharpening” behavior and an average 10.5% increase in penetration depth compared to conventional 95W penetrators. An acute head remained on the fine-grained 95W rod with SEM results revealing many micro-cracks and small debris on surface layer of the rod head. The stress-strain curves collected in the Split Hopkinson Pressure Bar (SHPB) experiment showed that critical failure strain values of the fine-grained 95W were 0.12 and 0.39 at strain rate of 2×10{sup 3} s{sup −1} and 3.9×10{sup 3} s{sup −1}, respectively, approximately 40% and 10% lower than those of the conventional 95W. The dynamic strength values of fine-grained 95W were 2100 MPa and 2520 MPa, respectively, which were 500 MPa and 520 MPa higher than those of the conventional 95W. The relationship among microstructure, mechanical property and “self-sharpening” behavior of fine-grained 95W is discussed in this work.

  14. Mechanical properties of tungsten alloys with Y{sub 2}O{sub 3} and titanium additions

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, M.V., E-mail: mariavega.aguirre@upm.es [Departamento de Tecnologias Especiales Aplicadas a la Aeronautica, Universidad Politecnica de Madrid, E.U.I.T. Aeronautica, 28040 Madrid (Spain); Martin, A.; Pastor, J.Y. [Departamento de Ciencia de Materiales-CISDEM, Universidad Politecnica de Madrid.E.T.S. Ingenieros de Caminos, 28040 Madrid (Spain); LLorca, J. [Departamento de Ciencia de Materiales-CISDEM, Universidad Politecnica de Madrid.E.T.S. Ingenieros de Caminos, 28040 Madrid (Spain); Instituto Madrileno de Estudios Avanzados en Materiales (Instituto IMDEA-Materiales), Ingenieros de Caminos, 28040 Madrid (Spain); Monge, M.A.; Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2011-10-01

    In this research the mechanical behaviour of pure tungsten (W) and its alloys (2 wt.% Ti-0.47 wt.% Y{sub 2}O{sub 3} and 4 wt.% Ti-0.5 wt.% Y{sub 2}O{sub 3}) is compared. These tungsten alloys, have been obtained by powder metallurgy. The yield strength, fracture toughness and elastic modulus have been studied in the temperature interval of 25 deg. C to 1000 deg. C. The results have shown that the addition of Ti substantially improves the bending strength and toughness of W, but it also dramatically increases the DBTT. On the other hand, the addition of 0.5% Y{sub 2}O{sub 3}, is enough to improve noticeably the oxidation behaviour at the higher temperatures. The grain size, fractography and microstructure are studied in these materials. Titanium is a good grain growth inhibitor and effective precursor of liquid phase in HIP. The simultaneous presence of Y{sub 2}O{sub 3} and Ti permits to obtain materials with low pores presence.

  15. Dissimilar Joining of Stainless Steel and 5083 Aluminum Alloy Sheets by Gas Tungsten Arc Welding-Brazing Process

    Science.gov (United States)

    Cheepu, Muralimohan; Srinivas, B.; Abhishek, Nalluri; Ramachandraiah, T.; Karna, Sivaji; Venkateswarlu, D.; Alapati, Suresh; Che, Woo Seong

    2018-03-01

    The dissimilar joining using gas tungsten arc welding - brazing of 304 stainless steel to 5083 Al alloy had been conducted with the addition of Al-Cu eutectic filler metal. The interface microstructure formation between filler metal and substrates, and spreading of the filler metal were studied. The interface microstructure between filler metal and aluminum alloy characterized that the formation of pores and elongated grains with the initiation of micro cracks. The spreading of the liquid braze filler on stainless steel side packed the edges and appeared as convex shape, whereas a concave shape has been formed on aluminum side. The major compounds formed at the fusion zone interface were determined by using X-ray diffraction techniques and energy-dispersive X-ray spectroscopy analysis. The micro hardness at the weld interfaces found to be higher than the substrates owing to the presence of Fe2Al5 and CuAl2 intermetallic compounds. The maximum tensile strength of the weld joints was about 95 MPa, and the tensile fracture occurred at heat affected zone on weak material of the aluminum side and/or at stainless steel/weld seam interface along intermetallic layer. The interface formation and its effect on mechanical properties of the welds during gas tungsten arc welding-brazing has been discussed.

  16. Heavy metal contamination in canned foods

    International Nuclear Information System (INIS)

    Sand, W.A.; Flex, H.; Allan, K.F.; Mahmoud, R.M.; Abdel-Haleem, A.E.

    2001-01-01

    The work carried out in this paper aims to the study of contamination of different foodstuffs, that are consumed frequently in our daily life, such as tomatoes concentrate, jam, tuna, and bean, as a result of canning in glass or tin cans. The effect of the storage time on the contamination of the aforementioned foods with heavy metals was also investigated. The technique used for the simultaneous determination of these elements was the instrumental neutron activation analysis (INAA). This technique was selected due to its high accuracy, sensitivity and selectivity. In the light of the obtained results it was suggested that tin cans is the best choice for canning jam and it is suitable also for preserving tuna. On the other hand, glass utensils were found to be the most suitable for preserving tomatoes concentrate. detailed studies are needed to throw more light on the effect of canning material on the concentration level of both essential and toxic trace elements in bean

  17. Heavy metal removal using reverse osmosis

    Directory of Open Access Journals (Sweden)

    Lucia Gajdošová

    2009-12-01

    Full Text Available The aim of this work was to study reverse osmosis characteristics for copper, nickel and zinc removal from technological aqueoussolutions. Reverse osmosis (RO is a separation process that uses pressure to force a solution through a membrane that retainsthe solute on one side and allows the pure solvent to pass to the other side. A polyamide thin-film composite membrane TW30-1812-50was used. The difference in flux decline is significant. There is a significant difference in flux decline depending on the anions of usedheavy metal salts. The heavy metal concentration also has a significant influence on the membrane separation. There is alsoa significant difference in flux decline depending on the transmembrane pressure.

  18. Hydroponic phytoremediation of heavy metals and radionuclides

    International Nuclear Information System (INIS)

    Hartong, J.; Szpak, J.; Hamric, T.; Cutright, T.

    1998-01-01

    It is estimated that the Departments of Defense, Energy, and Agriculture will spend up to 300 billion federal dollars on environmental remediation during the next century. Current remediation processes can be expensive, non-aesthetic, and non-versatile. Therefore, the need exists for more innovative and cost effective solutions. Phytoremediation, the use of vegetation for the remediation of contaminated sediments, soils, and ground water, is an emerging technology for treating several categories of persistent, toxic contaminants. Although effective, phytoremediation is still in a developmental stage, and therefore is not a widely accepted technology by regulatory agencies and public groups. Research is currently being conducted to validate the processes effectiveness as well as increase regulatory and community acceptance. This research will focus on the ability of plants to treat an aquifer contaminated with heavy metals and radionuclides. Specifically, the effectiveness of hydroponically grown dwarf sunflowers and mustard seed will be investigated

  19. Hydroponic phytoremediation of heavy metals and radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Hartong, J; Szpak, J; Hamric, T; Cutright, T

    1998-07-01

    It is estimated that the Departments of Defense, Energy, and Agriculture will spend up to 300 billion federal dollars on environmental remediation during the next century. Current remediation processes can be expensive, non-aesthetic, and non-versatile. Therefore, the need exists for more innovative and cost effective solutions. Phytoremediation, the use of vegetation for the remediation of contaminated sediments, soils, and ground water, is an emerging technology for treating several categories of persistent, toxic contaminants. Although effective, phytoremediation is still in a developmental stage, and therefore is not a widely accepted technology by regulatory agencies and public groups. Research is currently being conducted to validate the processes effectiveness as well as increase regulatory and community acceptance. This research will focus on the ability of plants to treat an aquifer contaminated with heavy metals and radionuclides. Specifically, the effectiveness of hydroponically grown dwarf sunflowers and mustard seed will be investigated.

  20. Heavy metals biogeochemistry in abandoned mining areas

    Directory of Open Access Journals (Sweden)

    Favas P. J. C.

    2013-04-01

    Full Text Available Plants growing on the abandoned Portuguese mines, highly contaminated with W, Sn, As, Cd, Cu, Zn and Pb, have been studied for their biogeochemical indication/prospecting and mine restoration potential. The results of analysis show that the species best suited for biogeochemical indicating are: aerial tissues of Halimium umbellatum (L. Spach, for As and W; leaves of Erica arborea L. for Bi, Sn, W and mostly Pb; stems of Erica arborea L. for Pb; needles of Pinus pinaster Aiton and aerial tissues of Pteridium aquilinum (L. Kuhn for W; and leaves of Quercus faginea Lam. for Sn. The aquatic plant studied (Ranunculus peltatus Schrank can be used to decrease the heavy metals, and arsenic amounts into the aquatic environment affected by acid mine drainages.

  1. Remediation of soils contaminated with heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Boni, M.R.; D' Aprile, L. [Univ. of Rome ' ' La Sapienza' ' , Dept. of Hydraulic Transportation and Roads (Italy)

    2001-07-01

    In December 1999 Italy issued the national regulation (DM 471/99) for the clean-up of contaminated sites. This regulation applies both to derelict and to still operating industrial plants and waste management facilities. Target concentration values for clean-up interventions are issued and the requirements for design and planning of technical operation are defined. The selection of the appropriate clean-up technology are based on the following main criteria: - reduce the concentration in environmental media and the migration of pollutants without removing soil off-site; - in order to reduce contaminated material removal and transportation, remedial actions of soil, subsoil and groundwater should preferably be based on in-situ treatments. In-situ technologies commonly applied in Italy to the remediation of soils contaminated by heavy metals (As, Cd, Cr, Hg, Pb) are: - containment (caps, vertical barriers); - soil flushing; - cement based solidification/stabilization. (orig.)

  2. Heavy metal levels in soil samples from highly industrialized Lagos ...

    African Journals Online (AJOL)

    Anyakora

    2013-09-05

    Sep 5, 2013 ... The effect of heavy metals on the environment is of serious concern and threatens life in all forms. Environmental ... have affected the quality of soil due to contamination of soil with heavy metals and the consequent effects on the ..... tested for remediation of chromium-contaminated soils. (Collen, 2003).

  3. Physico-chemical characteristics and Heavy metal levels in Drinking ...

    African Journals Online (AJOL)

    Physico-chemical characteristics and Heavy metal levels in Drinking Water ... composition was analysed using X-ray Fluorescence spectroscopy. Majority of the water samples had neutral pH (6.80 – 7.20) few were slightly alkaline and one was acidic. ... Heavy metals (copper and lead), rare earth metals (gallium, rubidium, ...

  4. Heavy metals in soils of cocoa plantation (Theobroma cacao L.)

    Science.gov (United States)

    Cocoa has experienced significant growth in recent years in Peru and the presence of heavy metals in the soils of these plantations is a potential problem for the export of this product. Contents of heavy metals (Cd, Ni, Pb, Fe, Cu, Zn, Mn) in soils from 19 plantations that have been in production f...

  5. Selected mineral and heavy metal concentrations in blood and ...

    African Journals Online (AJOL)

    Unknown

    Pb in the dead vultures were generally above values characteristic of heavy metal poisoning. ... of the food chain), may accumulate and concentrate heavy metals in their ..... µg/g wet weight) (Honda et al., 1990), which validates the order of ...

  6. Heavy metals concentration in various tissues of two freshwater ...

    African Journals Online (AJOL)

    Heavy metals like cadmium, zinc, copper, chromium, lead and mercury were measured in the various tissues of Labeo rohita and Channa striatus and in the water samples collected from ... The values of heavy metals concentration in the present study are within the maximum permissible levels for drinking water and fish.

  7. A Review of Polycyclic Aromatic Hydrocarbons and Heavy Metal ...

    African Journals Online (AJOL)

    A Review of Polycyclic Aromatic Hydrocarbons and Heavy Metal Contamination of Fish from Fish Farms. ... Journal of Applied Sciences and Environmental Management ... Polycyclic aromatic hydrocarbons (PAHs) and heavy metals contribute to pollutants in aquaculture facilities and thus need to be further investigated.

  8. Fractionation, characterization and speciation of heavy metals in ...

    African Journals Online (AJOL)

    Speciation of heavy metals in soils determines the availability for metals for plant uptake and potential for contamination of groundwater following application of composts to agricultural lands. Methods used to characterize heavy metals in solid phase of composts and compost amended soils include physical fractionation ...

  9. Urban water pollution by heavy metals and health implication in ...

    African Journals Online (AJOL)

    Studies of common heavy metals were conducted at Onitsha, Anambra State, the most urbanized city in Southeastern Nigeria. It was discovered that both surface and subsurface water were heavily polluted. Seven (7) heavy metals namely: arsenic (As+2), cadmium (Cd+2), lead (Pb+2), mercury (Hg+2), zinc (Zn+2), copper ...

  10. Heavy Metals Pollution on Surface Water Sources in Kaduna ...

    African Journals Online (AJOL)

    This study examine the effects of heavy metal pollutants to aquatic ecosystems and the environment by considering the role of urban, municipal, agricultural, industrial and other anthropogenic processes as sources of heavy metal pollution in surface water sources of Kaduna metropolis. Samples of the polluted water were ...

  11. Bioaccumulation of Heavy Metals by Moringa Oleifera in Automobile ...

    African Journals Online (AJOL)

    Plants accumulate minerals essential for their growth from the environment alongside with heavy metals from contaminated areas.This study investigated bioaccumulation of heavy metals by Moringa oleifera in automobile workshops in three selected local government areas in Ibadan. This was done with a view to ...

  12. Occurrence and distribution of heavy metals in indoor settled ...

    African Journals Online (AJOL)

    The results showed widespread heavy metals contamination especially Fe and Zn, which were present as the highest concentration while Cd was the lowest in the settled particles (dust). The order of occurrence of heavy metals in settled particles (dust) collected indoor in 2007 and 2008 respectively were as follows, ...

  13. Determination of Some Heavy Metals in Selected Beauty and ...

    African Journals Online (AJOL)

    Several epidemiologic studies have investigated the potential carcinogenicity of human exposure to heavy metals from diverse sources but few or none was on African black and beauty soaps. Hence, this study examines the presence of some heavy metals in selected African black and beauty soaps commonly used in ...

  14. Assessment and bioremediation of heavy metals from crude oil ...

    African Journals Online (AJOL)

    The assessment of the levels of heavy metals present in crude oil contaminated soil and the application of the earthworm - Hyperiodrilus africanus with interest on the bioremediation of metals from the contaminated soil was investigated within a 90-days period under laboratory conditions. Selected heavy metals such as ...

  15. Heavy metal biosorption sites in Penicillium cyclopium | Tsekova ...

    African Journals Online (AJOL)

    The biomass of Penicillium cyclopium was subjected to chemical treatment to study the role of the functional groups in the biosorption of heavy metal ions. The modifications of the functional groups were examined with infrared spectroscopy. Hydroxyl groups were identified as providing the major sites of heavy metal ...

  16. Removal of heavy metals from waste water of tanning leather ...

    African Journals Online (AJOL)

    The most dominant A. candidus on the isolation plates exhibited the highest activity for biosorption of heavy metals. The results indicate that fungi of contaminated soils have high level of metal biosorption capacities. Keywords: Fungi, industrial wastewater, biosorption, heavy metals. African Journal of Biotechnology Vol.

  17. Applicability of concentration factors for the heavy metals hazard identification

    International Nuclear Information System (INIS)

    Guzzi, Luigi

    2006-01-01

    The bioconcentration factor (BCF) and bioaccumulation factor (BAF) used as criteria for heavy metals hazards identification are inadequate. These considerations is based on the argument that the BCF-BAF model was developed and validated for xenobiotic synthetic organic substances and that does not recognize the complex internal metal dynamic of uptake, the internal sequestration, and the essentially of some heavy metals [it

  18. Safety Evaluation of Osun River Water Containing Heavy Metals and ...

    African Journals Online (AJOL)

    Summary: This study evaluated the pH, heavy metals and volatile organic compounds (VOCs) in Osun river water. It also evaluated its safety in rats. Heavy metals were determined by atomic absorption spectrophotometry (AAS) while VOCs were determined by gas chromatography coupled with flame ionization detector ...

  19. Evaluation of heavy metal uptake and translocation by Acacia ...

    African Journals Online (AJOL)

    Many organic and inorganic pollutants, including heavy metals are being transported and mixed with the cultivated soils and water. Heavy metals are the most dangerous pollutants as they are nondegradable and accumulate and become toxic to plants and animals. An experiment was conducted in the glasshouse to ...

  20. Comparative assessment of heavy metal removal by immobilized ...

    African Journals Online (AJOL)

    Microorganisms play a vital role in heavy metal contaminated soil and wastewater by the mechanisms of biosorption. In this study, heavy metal resistant bacteria were isolated from an electroplating industrial effluent samples that uses copper, cadmium and lead for plating. These isolates were characterized to evaluate their ...

  1. assessment of heavy metals concentration in drinking water ...

    African Journals Online (AJOL)

    userpc

    guidelines (WHO 2005). Findings suggest that continues water quality monitoring should be carried out to check the concentration levels of heavy metals in that area, to prevent them from been above the limit of WHO. Keywords: Atomic Absorption Spectrophotometers, Heavy Metals, Water, Kauru Local. Government Area.

  2. Uptake and elimination kinetics of heavy metals by earthworm ...

    African Journals Online (AJOL)

    Earthworm inoculation of petroleum hydrocarbon contaminated soil is thought to catalyze the bioremediation. Most bioremediation studies focus on the petroleum hydrocarbon content and not on the heavy metals. Here, the uptake kinetics of heavy metals by earthworm in used engine oil contaminated soil was investigated.

  3. Bioaccumulation of eight heavy metals in cave animals from Dashui ...

    African Journals Online (AJOL)

    ajl2

    karst caves and water systems in the caves are well developed. So, heavy metals can contaminate cave envi- ronment and affect cave animals. Karst topography is widely distributed in Guizhou province, China, accounting for 73.8% of the total land area. So, the examination of heavy metal pollution in cave soil and water ...

  4. Heavy metal accumulation in under crown Olea europaea L forest ...

    African Journals Online (AJOL)

    Heavy metal concentration in plants increased in site irrigation with wastewater. Zn, Pb and Ni exceeded their permitted limits in soils and Pb, Cr and Ni exceeded their permitted limits in roots of plants irrigated with wastewater. It was concluded that the use of wastewater in urban forest enriched the soils with heavy metals ...

  5. Tracing heavy metals in 'swine manure - maggot - chicken' production chain.

    Science.gov (United States)

    Wang, Wanqiang; Zhang, Wenjuan; Wang, Xiaoping; Lei, Chaoliang; Tang, Rui; Zhang, Feng; Yang, Qizhi; Zhu, Fen

    2017-08-21

    With the development of large-scale livestock farming, manure pollution has drawn much attention. Conversion by insects is a rapid and cost-effective new method for manure management. Swine manure conversion with maggots (Musca domestica larvae) has developed, and the harvested maggots are often used as animal feed. However, the flow of heavy metals from manure to downstream processes cannot be ignored, and therefore, heavy metal content was measured in untreated raw manure, maggot-treated manure, harvested maggots and maggot-eating chickens (chest muscle and liver) to evaluate potential heavy metal risks. The levels of zinc, copper, chromium, selenium, cadmium and lead had significant differences between untreated raw manure and maggot-treated manure. The concentrations of all detected heavy metals, except for cadmium and selenium, in maggots met the limits established by the feed or feed additive standards of many countries. The bioaccumulation factor (BAF) of heavy metals decreased with the increase of the maggot instar, indicating that heavy metals were discharged from the bodies of maggots with the growth of maggots. Also, the contents of overall heavy metals in chickens fed harvested maggots met the standards for food. In conclusion, regarding heavy metals, it is eco-safe to use maggots in manure management.

  6. THE HEAVY METALS CONNTENT IN VEGETABLES FROM MIDDLE SPIŠ AREA

    Directory of Open Access Journals (Sweden)

    Marek Slávik,Tomáš Tóth

    2014-02-01

    Full Text Available In the middle area of Spiš, it is significantly burden by heavy metals what is documented by radical content of Hg in soil from Rudňany 58.583645 mg.kg -1. On the content of heavy metals in vegetables grown in this soil it has the same effect. 61.5% samples exceeded the limit value of heavy metals. The most dangerous vegetables were Lactuca sativa L. The limit value was exceed in all determine heavy metals - Hg, Cd, Pb and Cu in this vegetables. In the case of Hg, the limit value exceed 93.86 times. For relatively safety is growing of Pisum sativum L., where there was no exceed any limits values. The root vegetables are dangerous, where the sample of Raphanus sativus L. exceed 6.71978 times the limit values for Pb although the content of lead in the soil was under hygienic limits. Transfer of heavy metals into consume parts of vegetables was no limited by high content of humus into soil. Transfer of heavy metals into consume parts of vegetables was no limited by weakly alkaline soil reaction. These factors are considered for factors limited mobility and input heavy metals into plants. We determined heavy metals by AAS method on a Varian 240 FS and method AMA 254.

  7. Heavy metal contamination of some vegetables from pesticides and ...

    African Journals Online (AJOL)

    Vegetable farming in developing countries is characterized by the indiscriminate application of pesticides and the resultant pollution of agricultural soil with heavy metals that form constituents of these pesticides. These heavy metals have long term toxicity to human and other biota in the ecosystem. This problem is ...

  8. Comparative Studies on Mosses for Heavy Metals Pollution ...

    African Journals Online (AJOL)

    The sources of these heavy metals were discovered to include: vehicular emission and incineration of domestic wastes and the heavy metals from these sources were discovered to pose severe toxicological risks to the environment and human health. Samples of mosses were collected at eight different locations in each ...

  9. X-ray fluorescence spectroscopic determination of heavy metals and ...

    African Journals Online (AJOL)

    Purpose: To determine the heavy metal and trace element composition of the powdered aerial parts of Origanum sipyleum L. and its water extract. Methods: The heavy metal and trace elements content of the powdered plant material and 2 % aqueous extract were evaluated by x-ray fluorescence spectroscopy with silicon ...

  10. Heavy Metals Accumulation Characteristics of Vegetables in Hangzhou City, China

    Directory of Open Access Journals (Sweden)

    GU Yan-qing

    2015-08-01

    Full Text Available A field survey of heavy metal concentrations in soils and vegetables grown in 30 vegetable farmlands of Hangzhou City were carried out. Through calculating the bioconcentration factor(BCFand transfer factor(TFfor different heavy metals(Cu, Zn, Cd, Cr and Pbin 27 kinds of different vegetables which belong to leafy vegetables, root vegetables or eggplant fruit vegetables, assessing their accumulation characteristics of heavy metals according to the differences of the bio-concentration factor, the reasonable proposals were put forward to optimize the planting structure of vegetables in mild and middle-level heavy metal contamination soils. The experimental results were as follows: In soils with mild and middle-level heavy metal contamination, leafy vegetables, such as crown daisy, cabbage, celery and Chinese long cabbage, had relatively low enrichment ability of heavy metals, so as the root and fruit vegetables like white radish, carrot, tomatoes, hence these vegetables could be planted preferentially. In contrast, some kinds of vegetables, including white amaranth, red amaranth, tatsoi, broccoli, gynura, brassica juncea and lettuce of leafy vegetables, lactuca sativa, taro, red radish and cherry radish of rhizome vegetables and sweet pepper of fruit vegetables, had relatively high accumulation ability of heavy metal, which should be avoided to be planted in soils with mild and middle-level heavy metal contamination.

  11. Heavy metals – a silent threat to health

    Directory of Open Access Journals (Sweden)

    Karolina Kosek-Hoehne

    2017-01-01

    Environmental pollution makes it impossible to produce goods and food from products completely free from heavy metals contamination. That is why we should focus on reducing the amount of heavy metals to the minimum when it comes to the world around us.

  12. selected heavy metals in some vegetables produced through ...

    African Journals Online (AJOL)

    toshiib

    Haramaya University; P. O. Box 138, Dire Dawa, Ethiopia. 10013 ... and trace elements that have potential health benefits [1]. ... leads to a build-up of heavy metals in soils and foods [3]. Exposure of ... Based on the effect of heavy metals on ... (Buck Scientific Model 210VGP AAS, East Norwalk, USA) with air-acetylene flame.

  13. Heavy Metal Pollution of Vegetable Crops Irrigated with Wastewater ...

    African Journals Online (AJOL)

    User

    Cr (< 0.006), Cd (< 0.002) and Co (< 0.005), soil Fe (164.38; 162.92), Mn (39.39; 20.09), Cu (7.21; ... extent of heavy metal contamination, steps must be taken to reduce human activities at the sites. ...... The degree of toxicity of heavy metals to.

  14. Predicting toxic heavy metal movements in upper Sanyati catchment ...

    African Journals Online (AJOL)

    Water samples from boreholes located in areas where mining, mineral processing and agricultural activities were dominant, yielded the highest values of toxic heavy metals. Dilution Attenuation Factor (DAF) for each toxic heavy metal was calculated to observe metal behaviour along the contaminant path for each season.

  15. Physicochemical characteristics and heavy metal levels in soil ...

    African Journals Online (AJOL)

    Distribution pattern of heavy metals in petrol stations, abattoirs, mechanic workshops and hospital incinerator sites were Mn > Zn > Pb > Cd, while for dumpsites Zn > Mn > Pb > Cd. Pollution index indicated that soil qualities varied between slightly contaminated to severely polluted status. This showed that the heavy metal ...

  16. Atmospheric heavy metal deposition in the Copenhagen area

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, A; Hovmand, M F; Johnsen, I

    1978-10-01

    Transport of heavy metals from the atmosphere to the soil and vegetation takes place by dust fall, bulk precipitation, and gas/aerosol adsorption processes. Atmospheric dry and wet deposition of the heavy metals lead, zinc, nickel, vanadium, iron, and copper over the Copenhagen area was measured by sampling in plastic funnels from 17 stations throughout the area for 12 months. Epigeic bryophytes, epiphytic lichen, and topsoil samples were analyzed. A linear correlation between bulk precipitation and heavy metal concentration in lichens and bryophytes was found. An exponential correlation between bulk precipitation and heavy metal concentration in soil was noted. Regional variation of the heavy metal levels in the Copenhagen area was described, and three sub-areas with high metal burdens were distinguished. (10 diagrams, 8 graphs, 13 references, 2 tables)

  17. Sewage sludge pyrolysis - the distribution of heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Kistler, R.; Widmer, F.; Brunner, P.

    1986-01-01

    The paper informs about the heavy metal contents of sewage sludges and discusses the origin of household, industry and surface sewerage of the respective heavy metals. The study aimed at assessing whether and in how far heavy metal volatility may be checked by reducing the temperature during sewage sludge pyrolysis. The testing equipment used was made of glass/silica glass. Instead of in particles heavy metals were precipitated in the gaseous state. Except from mercury heavy metals are retained by the ashes up to temperatures from 450 to 555/sup 0/C. Due to the persistence of mercury care should be taken to keep the sewerage clear of it from the very beginning. Emissions caused by reactor materials can be avoided by choosing appropriate pyrolysis reactors.

  18. Removal of dissolved heavy metals and radionuclides by microbial spores

    International Nuclear Information System (INIS)

    Revis, N.W.; Hadden, C.T.; Edenborn, H.

    1997-01-01

    Microbial systems have been shown to remove specific heavy metals from contaminated aqueous waste to levels acceptable to EPA for environmental release. However, systems capable of removing a variety of heavy metals from aqueous waste to environmentally acceptable levels remain to be reported. The present studies were performed to determine the specificity of spores of the bacterium Bacillus megaterium for the adsorption of dissolved metals and radionuclides from aqueous waste. The spores effectively adsorbed eight heavy metals from a prepared metal mix and from a plating rinse waste to EPA acceptable levels for waste water. These results suggest that spores have multiple binding sites for the adsorption of heavy metals. Spores were also effective in adsorbing the radionuclides 85 strontium and 197 cesium. The presence of multiple sites in spores for the adsorption of heavy metals and radionuclides makes this biosorbent a good candidate for the treatment of aqueous wastes associated with the plating and nuclear industries. 17 refs., 4 tabs

  19. [Biosorption of heavy metals in fluoritum decoction by fungal mycelium].

    Science.gov (United States)

    Cui, Pei-wu; Hu, Wei; Hu, Ya-qiang; Tan, Zhao-yang

    2014-09-01

    To explore the biosorption technology of heavy metals in Fluoritum decoction by fungal mycelium. Four factors including fungal mycelium amount, adsorption time, pH value and temperature were employed to estimate the fungal biomass adsorption conditions for removing the heavy metals in Fluoritum decoction. Then an orthogonal experimental design was taken to optimize the biosorption process, and the removal efficiency was also evaluated. Under the optimized conditions of 1.0 g/50 mL Fluoritum decoction, 3 hours adsorption time, pH 5.0 and 40 degrees C, a result of 70.12% heavy metals removal rate was accomplished with 35.99% calcium ion loss. The study indicates that removing of heavy metals in Fluoritum decoction through fungal mycelium is feasible, and the experiment results can also provide a basis for further research on biosorption of heavy metals in traditional Chinese medicine

  20. Microstructure and Mechanical Properties of Nano-Size Zirconium Carbide Dispersion Strengthened Tungsten Alloys Fabricated by Spark Plasma Sintering Method

    International Nuclear Information System (INIS)

    Xie Zhuoming; Liu Rui; Fang Qianfeng; Zhang Tao; Jiang Yan; Wang Xianping; Liu Changsong

    2015-01-01

    W-(0.2, 0.5, 1.0)wt% ZrC alloys with a relative density above 97.5% were fabricated through the spark plasma sintering (SPS) method. The grain size of W-1.0wt% ZrC is about 2.7 μm, smaller than that of pure W and W-(0.2, 0.5)wt% ZrC. The results indicated that the W-ZrC alloys exhibit higher hardness at room temperature, higher tensile strength at high temperature, and a lower ductile to brittle transition temperature (DBTT) than pure W. The tensile strength and total elongation of W-0.5wt% ZrC alloy at 700 °C is 535 MPa and 24.8%, which are respectively 59% and 114% higher than those of pure W (337 MPa, 11.6%). The DBTT of W-(0.2, 0.5, 1.0)wt% ZrC materials is in the range of 500°C–600°C, which is about 100 °C lower than that of pure W. Based on microstructure analysis, the improved mechanical properties of the W-ZrC alloys were suggested to originate from the enhanced grain boundary cohesion by ZrC capturing the impurity oxygen in tungsten and nano-size ZrC dispersion strengthening. (paper)

  1. Developing mathematical models to predict tensile properties of pulsed current gas tungsten arc welded Ti-6Al-4V alloy

    International Nuclear Information System (INIS)

    Balasubramanian, M.; Jayabalan, V.; Balasubramanian, V.

    2008-01-01

    Titanium (Ti-6Al-4V) alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding process of titanium alloy is frequently gas tungsten arc (GTA) welding due to its comparatively easier applicability and better economy. In the case of single pass GTA welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. Many considerations come into the picture and one need to carefully balance various pulse current parameters to arrive at an optimum combination. Hence, in this investigation an attempt has been made to develop mathematical models to predict tensile properties of pulsed current GTA welded titanium alloy weldments. Four factors, five level, central composite, rotatable design matrix is used to optimise the required number of experiments. The mathematical models have been developed by response surface method (RSM). The adequacy of the models has been checked by ANOVA technique. By using the developed mathematical models, the tensile properties of the joints can be predicted with 99% confidence level

  2. Developing mathematical models to predict tensile properties of pulsed current gas tungsten arc welded Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanian, M. [Department of Production Engineering, Sathyabama University, Old Mamallapuram Road, Chennai 600 119 (India)], E-mail: manianmb@rediffmail.com; Jayabalan, V. [Department of Manufacturing Engineering, Anna University, Guindy, Chennai 600 025 (India)], E-mail: jbalan@annauniv.edu; Balasubramanian, V. [Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002 (India)], E-mail: visvabalu@yahoo.com

    2008-07-01

    Titanium (Ti-6Al-4V) alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding process of titanium alloy is frequently gas tungsten arc (GTA) welding due to its comparatively easier applicability and better economy. In the case of single pass GTA welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. Many considerations come into the picture and one need to carefully balance various pulse current parameters to arrive at an optimum combination. Hence, in this investigation an attempt has been made to develop mathematical models to predict tensile properties of pulsed current GTA welded titanium alloy weldments. Four factors, five level, central composite, rotatable design matrix is used to optimise the required number of experiments. The mathematical models have been developed by response surface method (RSM). The adequacy of the models has been checked by ANOVA technique. By using the developed mathematical models, the tensile properties of the joints can be predicted with 99% confidence level.

  3. Indicators of Lake Temsah Potential by some heavy metals Heavy Metals in Sediment

    International Nuclear Information System (INIS)

    Abdel Sabour, M.F.; Aly, R.O.; Khalil, M.T.; Attwa, A.H.A.

    1999-01-01

    The Environmental impact of industrial, agricultural and domestic waster on heavy metals sediment content in lake Temsah has been investigated. Seven sites were chosen, differ in nature of activity and quantity of wastes, namely from south to north-west; Arab contractors shipyard workshop(A), The junction between the western logon and the lake(B), El-Temsah workshop (C), El-Temsah shipyard (private workshop) (D), El-Karakat workshop for SCA (E), El-Forsan drain out fall to the lake (F) and SCA Press outlet (G). Eight of heavy metal concentrations of concern (Fe, Mn, Zn, Cu, Co, Ni, Cd and Pb) were estimated in sediment samples collected from different chosen sites during the seasons; summer , autumn 1995 and winter , spring 1996. Results of this study reveal that pollution is directly related to the type of the activity in each site. Sediment samples results showed that the most suffering sites were found to be in the order of B> D> C> G> F, and the least polluted ones were E> A. And the highest polluted season was summer, whereas the least one was winter. It is obvious that the general mean values of Cu, Ni and Cd are exceeding the allowed concentrations documented for diverse trace components in coastal sediments. Strict regulations that must be followed in order to minimize this pollution specially, by heavy metals from marine workshop

  4. Heavy metals in trees and energy crops - a literature review

    International Nuclear Information System (INIS)

    Johnsson, Lars

    1995-12-01

    This literature review deals with the use of energy crops for cleaning of soils from heavy metals. It also deals with the use of low accumulating energy crops to be used on strongly contaminated soils where a low uptake of heavy metals is preferred, for example on mining deposits. In addition to the efforts to reduce the sources for heavy metal contamination of soils (for example commercial fertilizers and atmospheric deposition) the uptake and removal of heavy metals from the soils by the use of energy crops have recently been discussed as a method for cleaning of soils. Species from the Salix family (willow) have a greater potential for accumulating heavy metals than cereals which makes them interesting for this purpose. The Salix family consists of species with a great genetic variation. This will probably make it possible to find or develop clones with different characteristics suitable for cleaning of contaminated soils as well as for plant covering of soils that are extremely contaminated by heavy metals. In the former case an accumulation of heavy metals in the harvested parts, the shoots, is preferred. In the later case clones that do not accumulate heavy metals and maybe also clones with only root accumulation are preferred. There are also Salix clones with a specific accumulation of heavy metals which makes it possible to clean soils from a toxic metal and at the same time avoid the risk for deficiency of essential metals, for example Zn. The greatest potential to clean soils by the use of energy crops, is when the contamination levels in the soils are low, the areas to clean are large and when the time needed for cleaning is of minor importance. The most suitable soils are those where the metal contamination is located in the top soil layer and where the heavy metal concentrations in the sub soil layer are still low. 58 refs, 8 tabs, 1 fig

  5. Modeling of Heavy Metal Transformation in Soil Ecosystem

    Science.gov (United States)

    Kalinichenko, Kira; Nikovskaya, Galina N.

    2017-04-01

    The intensification of industrial activity leads to an increase in heavy metals pollution of soils. In our opinion, sludge from biological treatment of municipal waste water, stabilized under aerobic-anaerobic conditions (commonly known as biosolid), may be considered as concentrate of natural soil. In their chemical, physical and chemical and biological properties these systems are similar gel-like nanocomposites. These contain microorganisms, humic substances, clay, clusters of nanoparticles of heavy metal compounds, and so on involved into heteropolysaccharides matrix. It is known that microorganisms play an important role in the transformation of different nature substances in soil and its health maintenance. The regularities of transformation of heavy metal compounds in soil ecosystem were studied at the model of biosolid. At biosolid swelling its structure changing (gel-sol transition, weakening of coagulation contacts between metal containing nanoparticles, microbial cells and metabolites, loosening and even destroying of the nanocomposite structure) can occur [1, 2]. The promotion of the sludge heterotrophic microbial activities leads to solubilization of heavy metal compounds in the system. The microbiological process can be realized in alcaligeneous or acidogeneous regimes in dependence on the type of carbon source and followed by the synthesis of metabolites with the properties of flocculants and heavy metals extragents [3]. In this case the heavy metals solubilization (bioleaching) in the form of nanoparticles of hydroxycarbonate complexes or water soluble complexes with oxycarbonic acids is observed. Under the action of biosolid microorganisms the heavy metals-oxycarbonic acids complexes can be transformed (catabolised) into nano-sizing heavy metals- hydroxycarbonates complexes. These ecologically friendly complexes and microbial heteropolysaccharides are able to interact with soil colloids, stay in the top soil profile, and improve soil structure due

  6. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nikel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) seamless pipe and tube

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nikel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) seamless pipe and tube

  7. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045 and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) plate, sheet and strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045 and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) plate, sheet and strip

  8. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) rod, bar, and wire

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) rod, bar, and wire

  9. Leaching of heavy metals from steelmaking slags

    Directory of Open Access Journals (Sweden)

    Gomes, J. F. P

    2006-12-01

    Full Text Available Leaching tests with EAF and Ladle slags were performed, using a flow through test and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. The chemical analysis of the leachates during this period shows, in general, for both types of slag, an increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slag samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-through test, calcium and magnesium leached from solid slags are below 0.5% and all other metals below 0.1%. Leachates obtained with DIN 38414-S4 present, as expected, higher leaching values; however, these are inferior to 5 % (Ca and 1% (other elements.

    Este articulo contiene los resultados obtenidos en ensayos de lixiviación de escorias de acero (horno electrico y cuchara ejecutados siguiendo la metodologia de flujo dinámico así como el ensayo normalizado DIN 38414-S4. El primer ensayo intenta simular el comportamiento de lixiviación de las escorias en vertedero. Para las escorias ensayadas se han complementado los ensayos con el análisis químico de los lixiviados y se ha verificado un aumento de la liberación de metales pesados. El ensayo DIN 38414-S4 se ha utilizado para evaluar la lixiviación por agua de metales pesados, en muestras de escorias originales. Despues de un año de ensayos, se han observado niveles muy bajos de lixiviación. Los elementos mas lixiviados han sido calcio y magnesio. No obstante, en los ensayos de flujo dinámico, el calcio y el magnesio lixiviados de las escorias sólidas era menor de 0,5% y el resto de los otros metales era inferior a 0,1%. Los lixiviados obtenidos con el ensayo DIN 38414-S4 presentan, como era de esperar, valores

  10. Microalgae - A promising tool for heavy metal remediation.

    Science.gov (United States)

    Suresh Kumar, K; Dahms, Hans-Uwe; Won, Eun-Ji; Lee, Jae-Seong; Shin, Kyung-Hoon

    2015-03-01

    Biotechnology of microalgae has gained popularity due to the growing need for novel environmental technologies and the development of innovative mass-production. Inexpensive growth requirements (solar light and CO2), and, the advantage of being utilized simultaneously for multiple technologies (e.g. carbon mitigation, biofuel production, and bioremediation) make microalgae suitable candidates for several ecofriendly technologies. Microalgae have developed an extensive spectrum of mechanisms (extracellular and intracellular) to cope with heavy metal toxicity. Their wide-spread occurrence along with their ability to grow and concentrate heavy metals, ascertains their suitability in practical applications of waste-water bioremediation. Heavy metal uptake by microalgae is affirmed to be superior to the prevalent physicochemical processes employed in the removal of toxic heavy metals. In order to evaluate their potential and to fill in the loopholes, it is essential to carry out a critical assessment of the existing microalgal technologies, and realize the need for development of commercially viable technologies involving strategic multidisciplinary approaches. This review summarizes several areas of heavy metal remediation from a microalgal perspective and provides an overview of various practical avenues of this technology. It particularly details heavy metals and microalgae which have been extensively studied, and provides a schematic representation of the mechanisms of heavy metal remediation in microalgae. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Heavy metals in vegetables and potential risk for human health

    Directory of Open Access Journals (Sweden)

    Fernando Guerra

    2012-02-01

    Full Text Available Ingestion of vegetables containing heavy metals is one of the main ways in which these elements enter the human body. Once entered, heavy metals are deposited in bone and fat tissues, overlapping noble minerals. Slowly released into the body, heavy metals can cause an array of diseases. This study aimed to investigate the concentrations of cadmium, nickel, lead, cobalt and chromium in the most frequently consumed foodstuff in the São Paulo State, Brazil and to compare the heavy metal contents with the permissible limits established by the Brazilian legislation. A value of intake of heavy metals in human diets was also calculated to estimate the risk to human health. Vegetable samples were collected at the São Paulo General Warehousing and Centers Company, and the heavy metal content was determined by atomic absorption spectrophotometry. All sampled vegetables presented average concentrations of Cd and Ni lower than the permissible limits established by the Brazilian legislation. Pb and Cr exceeded the limits in 44 % of the analyzed samples. The Brazilian legislation does not establish a permissible limit for Co contents. Regarding the consumption habit of the population in the São Paulo State, the daily ingestion of heavy metals was below the oral dose of reference, therefore, consumption of these vegetables can be considered safe and without risk to human health.

  12. Impact of heavy metals on the female reproductive system

    Directory of Open Access Journals (Sweden)

    Piotr Rzymski

    2015-05-01

    Full Text Available Introduction. It has been recognized that environmental pollution can affect the quality of health of the human population. Heavy metals are among the group of highly emitted contaminants and their adverse effect of living organisms has been widely studied in recent decades. Lifestyle and quality of the ambient environment are among these factors which can mainly contribute to the heavy metals exposure in humans. Objective. A review of literature linking heavy metals and the female reproductive system and description of the possible associations with emission and exposure of heavy metals and impairments of female reproductive system according to current knowledge. Results. The potential health disorders caused by chronic or acute heavy metals toxicity include immunodeficiency, osteoporosis, neurodegeneration and organ failures. Potential linkages of heavy metals concentration found in different human organs and blood with oestrogen-dependent diseases such as breast cancer, endometrial cancer, endometriosis and spontaneous abortions, as well as pre-term deliveries, stillbirths and hypotrophy, have also been reported. Conclusions. Environmental deterioration can lead to the elevated risk of human exposure to heavy metals, and consequently, health implications including disturbances in reproduction. It is therefore important to continue the investigations on metal-induced mechanisms of fertility impairment on the genetic, epigenetic and biochemical level.

  13. A Drinking Water Sensor for Lead and Other Heavy Metals.

    Science.gov (United States)

    Lin, Wen-Chi; Li, Zhongrui; Burns, Mark A

    2017-09-05

    Leakage of lead and other heavy metals into drinking water is a significant health risk and one that is not easily detected. We have developed simple sensors containing only platinum electrodes for the detection of heavy metal contamination in drinking water. The two-electrode sensor can identify the existence of a variety of heavy metals in drinking water, and the four-electrode sensor can distinguish lead from other heavy metals in solution. No false-positive response is generated when the sensors are placed in simulated and actual tap water contaminated by heavy metals. Lead detection on the four-electrode sensor is not affected by the presence of common ions in tap water. Experimental results suggest the sensors can be embedded in water service lines for long-time use until lead or other heavy metals are detected. With its low cost (∼$0.10/sensor) and the possibility of long-term operation, the sensors are ideal for heavy metal detection of drinking water.

  14. Heavy metal displacement in chelate-irrigated soil during phytoremediation

    Science.gov (United States)

    Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

    2003-03-01

    Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

  15. Adsorption of heavy metal ions on different clays

    International Nuclear Information System (INIS)

    Kruse, K.

    1992-01-01

    The aim of the present dissertation is to study the adsorption of heavy metal ions (Cd 2+ , Cu 2+ , Pb 2+ , Zn 2+ ) and their mixtures on clays. Different clays and bentonites (Ca 2+ -bentonite, activated Na + -bentonite, special heavy metal adsorber bentonite, two organophilic bentonites and a mixed layer clay) were used. The adsorbed metal ions were desorbed by appropriate solutions of HCl, EDTA and dioctadecyl dimethylammonium bromide. High concentrations of the heavy metal ions in the solutions can be reached. The desorption guarantees economical recycling. After desorption the clays were used (up to three times) for purification of contaminated water. The best experimental conditions, i.e. the highest adsorption of heavy metal ions from aqueous solutions was found for the greatest ratio of adsorbent/adsorbate. The adsorption was very fast. Calcium, sodium bentonites and the heavy metal adsorber bentonite attained the highest adsorption and desorption for Cu 2+, Zn 2+ and Pb 2+ ions. Cd 2+ ions were only absorbed by Silitonit, a special heavy metal absorber bentonite. The mixed layer clay (Opalit) ranges in adsorption and desorption properties below the unmodified Ca 2+ -bentonite (Montigel) or the activated Na + -bentonite. Only Tixosorb and Tixogel (organophilic bentonites) reach the lowest value of heavy metal adsorption. Only lead cations which are characterised by good polarizability were adsorbed at higher rates, therefore the organophilic bentonites are not appropriate for adsorption of heavy metal ions from aqueous solutions. Mixing of the metal ions generally decreases the adsorption of Pb 2+ and increases the adsorption of Cd 2+ . From mixtures if heavy metal ions adsorption and desorption of Cu 2+ ions reached a maximum for all clays. (author) figs., tabs., 56 refs

  16. The effect of surface depletion on the work function of arc-melted dilute solution tungsten-iridium alloys

    International Nuclear Information System (INIS)

    D'Cruz, L.A.; Bosch, D.R.; Jacobson, D.L.

    1991-01-01

    The requirements of thermionic electrode materials have emphasized the need for substantial improvements in microstructural stability, strength, and creep resistance at service temperature in excess of 2,500K. The present work extends an earlier study of the effective work function trends of a series of dilute solution tungsten, iridium alloys with iridium contents of 1, 3, and 5 wt%. Since the lifetime of candidate electrode materials is an important consideration, the present work attempts to evaluate the repeatability of the work function trends in these alloys. The effective work function was obtained from measurements of the current emitted from the electrode surface under UHV conditions in the temperature range of 1,800-2,500K using a Vacuum Emission Vehicle (VEV). The data generated in this work have been compared with data obtained in earlier studies performed on these alloys. It was found that the magnitude of the effective work function of these alloys was affected by changes in the subsurface iridium concentration. Furthermore, these alloys exhibited a dependence of the work function on temperature, after prolonged exposure to elevated temperatures. Such a temperature dependence can be explained by diffusion-controlled changes in the coverage of an iridium monolayer on the surface. It is proposed that the significant difference in effective work function trends obtained after prolonged exposure to elevated temperatures is a direct consequence of changes in the coverage of an iridium-rich monolayer on the electrode surface. The constitution of such a surface layer, however, would be governed by composition changes in the subsurface regions of the electrode caused thermally-activated transport processes

  17. Effects of alloying and transmutation impurities on stability and mobility of helium in tungsten under a fusion environment

    International Nuclear Information System (INIS)

    Wu Xuebang; Kong Xiangshan; You Yuwei; Liu, C.S.; Fang, Q.F.; Chen Junling; Luo, G.-N.; Wang Zhiguang

    2013-01-01

    The behaviour of helium in metals is particularly significant in fusion research due to the He-induced degradation of materials. A small amount of impurities introduced either by intentional alloying or by transmutation reactions, will interact with He and lead the microstructure and mechanical properties of materials to change. In this paper, we present the results of first-principles calculations on the interactions of He with impurities and He diffusion around them in tungsten (W), including the interstitials Be, C, N, O, and substitutional solutes Re, Ta, Tc, Nb, V, Os, Ti, Si, Zr, Y and Sc. We find that the trapping radii of interstitial atoms on He are much larger than those of substitutional solutes. The binding energies between the substitutional impurities and He increase linearly with the relative charge densities at the He occupation site, indicating that He atoms easily aggregate at the low charge density site. The sequence of diffusion energy barriers of He around the possible alloying elements is Ti > V > Os > Ta > Re. The present results suggest that Ta might be chosen as a relatively suitable alloying element compared with other possible ones. (paper)

  18. Heavy metal contamination in bats in Britain

    International Nuclear Information System (INIS)

    Walker, L.A.; Simpson, V.R.; Rockett, L.; Wienburg, C.L.; Shore, R.F.

    2007-01-01

    Toxic metals are bioaccumulated by insectivorous mammals but few studies (none from Britain) have quantified residues in bats. We measured renal mercury (Hg), lead (Pb) and cadmium (Cd) concentrations in bats from south-west England to determine how they varied with species, sex, age, and over time, and if they were likely to cause adverse effects. Residues were generally highest in whiskered bats (Myotis mystacinus). Compared with other species, pipistrelle (Pipistrellus spp) and Natterer's bats (Myotis nattereri) had significantly lower kidney Hg and Pb concentrations, respectively. Renal Hg increased over time in pipistrelles but the contributory sources are unknown. Kidney Pb did not decrease over time despite concurrent declines in atmospheric Pb. Overall, median renal metal concentrations were similar to those in bats from mainland Europe and 6- to 10-fold below those associated with clinical effect, although 5% of pipistrelles had kidney Pb residues diagnostic of acute lead poisoning. - Heavy metal contamination has been quantified in bats from Britain for the first time and indicates increased accumulation of Hg and no reduction in Pb

  19. Toxic Heavy Metals: Materials Cycle Optimization

    Science.gov (United States)

    Ayres, Robert U.

    1992-02-01

    Long-term ecological sustainability is incompatible with an open materials cycle. The toxic heavy metals (arsenic, cadmium, chromium, copper, lead, mercury, silver, uranium/plutonium, zinc) exemplify the problem. These metals are being mobilized and dispersed into the environment by industrial activity at a rate far higher than by natural processes. Apart from losses to the environment resulting from mine wastes and primary processing, many of these metals are utilized in products that are inherently dissipative. Examples of such uses include fuels, lubricants, solvents, fire retardants, stabilizers, flocculants, pigments, biocides, and preservatives. To close the materials cycle, it will be necessary to accomplish two things. The first is to ban or otherwise discourage (e.g., by means of high severance taxes on virgin materials) dissipative uses of the above type. The second is to increase the efficiency of recycling of those materials that are not replaceable in principle. Here, also, economic instruments (such as returnable deposits) can be effective in some cases. A systems view of the problem is essential to assess the cost and effectiveness of alternative strategies.

  20. Heavy metal contamination in bats in Britain

    Energy Technology Data Exchange (ETDEWEB)

    Walker, L.A. [NERC Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS (United Kingdom); Simpson, V.R. [Wildlife Veterinary Investigation Centre, Jollys Bottom Farm, Chacewater, Truro, Cornwall TR4 8PB (United Kingdom); Rockett, L. [NERC Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS (United Kingdom); Wienburg, C.L. [NERC Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS (United Kingdom); Shore, R.F. [NERC Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS (United Kingdom)]. E-mail: rfs@ceh.ac.uk

    2007-07-15

    Toxic metals are bioaccumulated by insectivorous mammals but few studies (none from Britain) have quantified residues in bats. We measured renal mercury (Hg), lead (Pb) and cadmium (Cd) concentrations in bats from south-west England to determine how they varied with species, sex, age, and over time, and if they were likely to cause adverse effects. Residues were generally highest in whiskered bats (Myotis mystacinus). Compared with other species, pipistrelle (Pipistrellus spp) and Natterer's bats (Myotis nattereri) had significantly lower kidney Hg and Pb concentrations, respectively. Renal Hg increased over time in pipistrelles but the contributory sources are unknown. Kidney Pb did not decrease over time despite concurrent declines in atmospheric Pb. Overall, median renal metal concentrations were similar to those in bats from mainland Europe and 6- to 10-fold below those associated with clinical effect, although 5% of pipistrelles had kidney Pb residues diagnostic of acute lead poisoning. - Heavy metal contamination has been quantified in bats from Britain for the first time and indicates increased accumulation of Hg and no reduction in Pb.

  1. Heavy metal toxicity and iron chlorosis

    Energy Technology Data Exchange (ETDEWEB)

    DeKock, P C

    1956-01-01

    The toxicity of copper, nickel, cobalt, zinc, chromium, and manganese to mustard was studied in water culture, utilizing either the ionic form or the EDTA chelate of the metal in the presence of either ferric chloride or ferric EDTA. In presence of ferric chloride the activity of the metals in producing chlorosis was as given above, i.e. in the order of stability of their chelates. In the presence of ferric versenate, toxicity of the ionic metal was much reduced. The metal chelates gave very little indication of toxicity with either form of iron. It was found that the ratio of total phosphorus to total iron was higher in chlorotic plants than in green plants, irrespective of which metal was causing the toxicity. Copper could be demonstrated in the phloem cells of the root using biscyclohexanone-oxalydihydrazone as histochemical reagent. It is postulated that transport of iron probably takes place in the phloem as an active process. It would appear that as a major part of the iron in plant cells is attached to nucleo- or phospho-proteins, the heavy metals must be similarly attached to phospho-proteins.

  2. Leaching of heavy metals from timah langat amang

    International Nuclear Information System (INIS)

    Shukri bin Othman

    1990-01-01

    Accelerated leaching studies of amang from Timah Langat for heavy metals showed that the material was rather stable. From almost 24 types of heavy metals contained in the material, the metal that leached out most was Al, followed by Pb, U, Cu, Mn, Fe, Mg, Y and La but at smaller quantities. The studies also showed that amang was very porous. The high seepage rate resulted in the solubilities of the metals not reaching equilibrium. In that situation, the leaching of heavy metals from amang was dependent on the seepage rate of water, the height of the material, the volume of water that seeped through and the solubility of the metals

  3. SPS Fabrication of Tungsten-Rhenium Alloys in Support of NTR Fuels Development

    International Nuclear Information System (INIS)

    Webb, Jonathan A.; Charit, Indrajit; Sparks, Cory; Butt, Darryl P.; Frary, Megan; Carroll, Mark

    2011-01-01

    Tungsten metal slugs were fabricated via Spark Plasma Sintering (SPS) of powdered metals at temperatures ranging from 1575 K to 1975 K and hold times of 5 minutes to 30 minutes, using powders with an average diameter of 7.8 ?m. Sintered tungsten specimens were found to have relative densities ranging from 83 % to 94 % of the theoretical density for tungsten. Consolidated specimens were also tested for their Vickers Hardness Number (VHN), which was fitted as a function of relative density; the fully consolidated VHN was extrapolated to be 381.45 kg/mm2. Concurrently, tungsten and rhenium powders with average respective diameters of 0.5 ?m and 13.3 ?m were pre-processed either by High-Energy-Ball-Milling (HEBM) or by homogeneous mixing to yield W-25at.%Re mixtures. The powder batches were sintered at temperatures of 1975 K and 2175 K for hold times ranging from 0 minutes to 60 minutes yielding relative densities ranging from 94% to 97%. The combination of HEBM and sintering showed a significant decrease in the inter-metallic phases compared to that of the homogenous mixing and sintering.

  4. Corrosion characterisation of laser beam and tungsten inert gas weldment of nickel base alloys: Micro-cell technique

    International Nuclear Information System (INIS)

    Abraham, Geogy J.; Kain, V.; Dey, G.K.; Raja, V.S.

    2015-01-01

    Highlights: • Grain matrix showed better corrosion resistance than grain boundary. • Microcell studies showed distinct corrosion behaviour of individual regions of weldment. • TIG welding resulted in increased stable anodic current density on weld fusion zone. • LB welding resulted in high stable anodic current density for heat affected zone. - Abstract: The electrochemical studies using micro-cell technique gave new understanding of electrochemical behaviour of nickel base alloys in solution annealed and welded conditions. The welding simulated regions depicted varied micro structural features. In case of tungsten inert gas (TIG) weldments, the weld fusion zone (WFZ) showed least corrosion resistance among all other regions. For laser beam (LB) weldments it was the heat-affected zone (HAZ) that showed comparatively high stable anodic current density. The high heat input of TIG welding resulted in slower heat dissipation hence increased carbide precipitation and segregation in WFZ resulting in high stable anodic current density

  5. Study and development of solid fluxes for gas tungsten arc welding applied to titanium and its alloys and stainless steels

    International Nuclear Information System (INIS)

    Perry, N.

    2000-06-01

    Gas Tungsten Arc Welding uses an electric arc between the refractory tungsten electrode and the plates to be welded under an argon shielding gas. As a result, the joint quality is excellent, no pollution nor defects are to be feared, consequently this process is used in nuclear, aeronautic, chemical and food industries. Despite of this good qualities, GTAW is limited because of, on the one side, a poor penetrating weld pool and, on the other side, a week productivity rate. Indeed, up to 3 mm thick plates, machining and filler metal is needed. Multiple runs increase the defect's risks, the manufactory time and increase the deformations and the heat affected zone. The goal of this study is to break through this limits without any device investment. Active GTA welding (or ATIG) is a new technique with GTA device and an activating flux to be spread on the upper plate before welding. The arc, by plasma electrochemical equilibrium modifications, and the pool with the inner connective flows inversion, allow 7 mm thick joints in one run without edges machining or filler metal for both stainless steel and titanium alloys. This manuscript describes the development of these fluxes, highlights the several phenomena and presents the possibilities of this new process. This work, in collaboration with B.S.L. industries, leads to two flux formulations (stainless steel and titanium alloys) now in a commercial phase with CASTOLIN S.A. Moreover, B.S.L.industries produces a pressure device (nitrate column) with the ATIG process using more than 2800 ATIG welds. (author)

  6. Manufacturing and testing of self-passivating tungsten alloys of different composition

    Directory of Open Access Journals (Sweden)

    A. Calvo

    2016-12-01

    Bulk W-15Cr, W-10Cr-2Ti and W-12Cr-0.5Y alloys were manufactured by mechanical alloying followed by can encapsulation and HIP. This route resulted in fully dense materials with nano-structured grains. The ability of Ti and especially of Y to inhibit grain growth was observed in the W-10Cr-2Ti and W-12Cr-0.5Y alloys. Besides, Y formed Y-rich oxide nano-precipitates at the grain boundaries, and is thus expected to improve the mechanical behaviour of the Y-containing alloy. Isothermal oxidation tests at 800 ºC (1073K and oxidation tests under accident-like conditions revealed that the W-12Cr-0.5Y alloy exhibits the best oxidation behaviour of all alloys, especially in the accident-like scenario. Preliminary HHF tests performed at GLADIS indicated that the W-10Cr-2Ti alloy is able to withstand power densities of 2 MW/m2 without significant damage of the bulk structure. Thermo-shock tests at JUDITH-1 to simulate mitigated disruptions resulted in chipping of part of the surface of the as-HIPed W-10Cr-2Ti alloy. An additional thermal treatment at 1600 °C (1873K improves the thermo-shock resistance of the W-10Cr-2Ti alloy since only crack formation is observed.

  7. Heavy metals in the snow pack of Semey town

    International Nuclear Information System (INIS)

    Panin, M.S.; Esenzholova, A.Zh.; Toropov, A.S.

    2008-01-01

    The data about the maintenance of heavy metals in the snow pack in various zones of Semey and biogeochemical operation factors of snow pack in Semey are presented in this work. Also the correlation connection between elements is calculated.

  8. Toxic effect of heavy metals on aquatic environment | Baby ...

    African Journals Online (AJOL)

    Toxic effect of heavy metals on aquatic environment. ... International Journal of Biological and Chemical Sciences ... The indiscriminate discharge of industrial effluents, raw sewage wastes and other waste pollute most of the environments and ...

  9. Heavy metal and proximate composition associated with the ...

    African Journals Online (AJOL)

    User

    2014-05-08

    May 8, 2014 ... Levels of Cu, Mn, Pd and Zn in mushroom samples analysed were ... metal concentration in soil and fungal factors such as species ..... Levels of trace elements in the fruiting bodies ... Toxicity of non-radioactive heavy metals.

  10. Assessment of Heavy Metals Level of River Kaduna at Kaduna ...

    African Journals Online (AJOL)

    Journal of Applied Sciences and Environmental Management ... status and the implications of the heavy metal pollution on human health and the environment. ... metals discharged into the river especially from the industries and municipal ...

  11. Comparative assessment of heavy metal removal by immobilized ...

    African Journals Online (AJOL)

    EJIRO

    Key words: Biosorption, bacteria, heavy metal, dead bacterial cells, immobilization. INTRODUCTION ... Moreover, the metals cannot be degraded to harmless products and ... a sterile plastic container and taken immediately to the laboratory.

  12. Assessment of heavy metals in chicken feeds available in Sokoto ...

    African Journals Online (AJOL)

    ADEYEYE

    2014-12-08

    Dec 8, 2014 ... through eggs and meats. Supplementation of some ... heavy metal contaminations of chicken meat, eggs and other products .... processing and mixing of ingredients to the feed. ... Additives and Contaminants, 22(2): 141-. 149.

  13. Heavy metal pollution of vegetable crops irrigated with wastewater ...

    African Journals Online (AJOL)

    144) and edible parts of both exotic and traditional vegetables (samples = 240) irrigated with wastewater from some parts of Accra were studied. The concentrations of heavy metals in mg/l were quantified in wastewater from Accra and ...

  14. Determination of heavy metals and genotoxicity of water from an ...

    African Journals Online (AJOL)

    Determination of heavy metals and genotoxicity of water from an artesian well ... do Amaral, Vanessa Marques de Oliveira Moraes, Luciana Pereira Silva ... environmental interest because it is the most important zinc producer district of Brazil.

  15. Heavy Metals Levels in Fish Samples from North Central Nigerian ...

    African Journals Online (AJOL)

    MBI

    2014-12-24

    Dec 24, 2014 ... Most aquatic organisms are capable of accumulating heavy metals to concentrations ... This indicates that the fish samples could be used to monitor Mn and Cr pollution levels .... was carried out to remove any organic plastic.

  16. Determination of some heavy metals concentration in the tissues of ...

    African Journals Online (AJOL)

    Jen

    Department of Pure and Industrial Chemistry, Bayero University, Kano, P.M.B. 3011, Kano, Nigeria ... contamination (e.g. lead pipes), high ambient air concentrations near emission ... Thus heavy metals acquired through the food chain as a.

  17. Sorption of Heavy Metal Ions from Mine Wastewater by Activated ...

    African Journals Online (AJOL)

    Michael

    2016-12-02

    Dec 2, 2016 ... assess their heavy metal ions adsorption potential. The results show that the .... De-ionised water obtained from the Mineral. Engineering Laboratory of ... Batch adsorption experiment for each of the derived activated carbons ...

  18. Assessment of Heavy Metal Content of Branded Pakistani Herbal ...

    African Journals Online (AJOL)

    Erah

    analyzed using a flame atomic absorption spectrometer. Results: Most of the products exceeded the permissible limits for lead (100 %), cadmium (68 %), .... absorption spectrometry. M e ta l n a m ..... Determination of Heavy Metals in Medicinal.

  19. 92 Assessment of Heavy Metals Pollution in Dumpsites in Ilorin ...

    African Journals Online (AJOL)

    Choice-Academy

    Speciation and distribution of heavy metals in soil controls the degree to which ... observed that the groundwater is vulnerable to contamination as no treated ... toxic materials such as lead, cadmium, .... designing remediation programme for.

  20. Effect of depuration on heavy metal concentrations in periwinkle ...

    African Journals Online (AJOL)

    Tympanatonus fuscastus) was evaluated in this study. Periwinkle in depuration tanks were taken at intervals of 24, 48, 72 and 96 hours of depuration and analyzed for these heavy metals: Lead (Pb), Zinc (Zn), Chromium (Cr) and Cadmium (Cd).

  1. The effects of heavy metals concentration on some commercial fish ...

    African Journals Online (AJOL)

    Badmus B S

    heavy metals (lead, cadmium, copper and zinc) were analyzed and only copper and zinc were found to be present in the ... contents of essential minerals, vitamins and unsaturated fatty acids .... that the interaction effect is significant. This effect ...

  2. Heavy Metal Contents in Some Commonly Consumed Vegetables

    African Journals Online (AJOL)

    dell

    This work reports on the levels of cadmium, lead, copper, manganese and ... source of both heavy metals and essential trace elements due to their ... content, clay mineral and other soil chemical ... addition, the interactions of soil-plant root-.

  3. Heavy metal exposure in patients suffering from electromagnetic hypersensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Ghezel-Ahmadi, David, E-mail: david.ahmadi@web.de [Department of Psychiatry, University of Mainz (Germany); Engel, Alice; Weidemann, Joerg [Department of Psychiatry, University of Mainz (Germany); Budnik, Lygia Therese; Baur, Xaver [Institute for Occupational Medicine and Maritime Medicine (ZfAM), University of Hamburg (Germany); Frick, Ulrich [Department of Psychiatry, University of Regensburg (Germany); Department of Healthcare Management, Carinthia University of Applied Sciences (Austria); Hauser, Simone [Department of Psychiatry, University of Regensburg (Germany); Dahmen, Norbert [Department of Psychiatry, University of Mainz (Germany)

    2010-01-15

    Background: Risks from electromagnetic devices are of considerable concern. Electrohypersensitive (EHS) persons attribute a variety of rather unspecific symptoms to the exposure to electromagnetic fields. The pathophysiology of EHS is unknown and therapy remains a challenge. Objectives: Heavy metal load has been discussed as a potential factor in the symptomatology of EHS patients. The main objective of the study was to test the hypothesis of a link between EHS and heavy metal exposure. Methods: We measured lead, mercury and cadmium concentrations in the blood of 132 patients (n = 42 males and n = 90 females) and 101 controls (n = 34 males and n = 67 females). Results: Our results show that heavy metal load is of no concern in most cases of EHS but might play a role in exceptional cases. Conclusions: The data do not support the general advice to heavy metal detoxification in EHS.

  4. Heavy Metal Polluted Soils: Effect on Plants and Bioremediation Methods

    Directory of Open Access Journals (Sweden)

    G. U. Chibuike

    2014-01-01

    Full Text Available Soils polluted with heavy metals have become common across the globe due to increase in geologic and anthropogenic activities. Plants growing on these soils show a reduction in growth, performance, and yield. Bioremediation is an effective method of treating heavy metal polluted soils. It is a widely accepted method that is mostly carried out in situ; hence it is suitable for the establishment/reestablishment of crops on treated soils. Microorganisms and plants employ different mechanisms for the bioremediation of polluted soils. Using plants for the treatment of polluted soils is a more common approach in the bioremediation of heavy metal polluted soils. Combining both microorganisms and plants is an approach to bioremediation that ensures a more efficient clean-up of heavy metal polluted soils. However, success of this approach largely depends on the species of organisms involved in the process.

  5. Electrochemical activity of heavy metal oxides in the process of ...

    Indian Academy of Sciences (India)

    Unknown

    2002-02-02

    Feb 2, 2002 ... Electrochemical activity of heavy metal oxides in the process of chloride induced .... represents the protective barrier moderating the chloride attack which ... inhibitors and their influence on the physical properties of. Portland ...

  6. Potential Human Health Risk Assessment of Heavy Metals Intake via ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Gyawali et al., 2011). The concentrations of natural and synthetic ... traditional nutrients, heavy metals, pesticides and various other ... fertilizers and pesticides to soils, with a number of ..... selected brands of canned fish in Nigeria: Estimation of ...

  7. Heavy metal content of selected African leafy vegetables planted in ...

    African Journals Online (AJOL)

    Heavy metal content of selected African leafy vegetables planted in urban and peri-urban Nairobi, Kenya. ... African Journal of Environmental Science and Technology ... Government clean-up activities and monitoring of waste disposal is ...

  8. Heavy metal accumulation in a flow restricted, tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Laluraj, C.M.; Nair, M.; Joseph, T.; Sheeba, P.; Venugopal, P.

    Levels of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn), organic carbon content and textural characteristics in the surficial sediments of Cochin estuary (SW coast of India) and adjacent coast are presented. Anthropogenic inputs from...

  9. Seasonal variation in heavy metal concentration in mangrove foliage

    Digital Repository Service at National Institute of Oceanography (India)

    Untawale, A.G.; Wafar, S.; Bhosle, N.B.

    Seasonal variation in the concentration of some heavy metals in the leaves of seven species of mangrove vegetation from Goa, revealed that maximum concentration of iron and manganese occurs during the monsoon season without any significant toxic...

  10. Waste printing paper as analogous adsorbents for heavy metals in ...

    African Journals Online (AJOL)

    user

    heavy metals uptake from aqueous solutions but the recovery efficacy as economic and environmental ... system. 1 . Wastes containing metals are directly or indirectly discharge into the environment ... According to World health Organization. 5.

  11. Analysis of Heavy Metals Concentration in Kano Herbal ...

    African Journals Online (AJOL)

    2017-09-23

    Sep 23, 2017 ... toxic metals in the body system of the consumers of these herbal preparations in order to attain to safe and effective ..... heavy metal availability and vegetation recovery at a grown ... World Health Organization (WHO,. 2007).

  12. incidence of heavy metals in kano metropolis drinking water sources

    African Journals Online (AJOL)

    userpc

    corrosion of brass fittings of certain submersible pumps and pipes used in borehole and taps specifically. The contamination of well with heavy metals might be due to seepage of sewage ... Chloride determination (Agumetric method):.

  13. Evaluation of pollution status of heavy metals in the groundwater ...

    African Journals Online (AJOL)

    Evaluation of pollution status of heavy metals in the groundwater system around ... cadmium (Cd), mercury (Hg), manganese (Mn), lead (pb) and arsenic (As) as ... Water samples (from bore holes, hand-dug wells, ponds and streams) were ...

  14. Biosorption of heavy metals and uranium from dilute solutions

    International Nuclear Information System (INIS)

    Schneider, I.A.H.; Misra, M.; Smith, R.W.

    1995-01-01

    Eichhornia crassipes approaches being a scourge in many parts of the world, choking waterways and hindering transport upon them. At the same time it is known to readily abstract heavy metal ions from water and, thus, aids in the removal of heavy metals found in such waters. This paper considers the possibility of using specific parts of the plant as an inexpensive adsorbent for the removal of heavy metals from contaminated chemical and mining industry waste waters. In particular the root of the plant was found to be an excellent accumulator of heavy metal ions including uranium from solution. It is also suggested that dried roots of the plant might be placed in simple bags and used in a very low cost metal ion removal system

  15. Assessment of Heavy Metals in Waterleaf from Various Sources in ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Standard method was followed for sample treatment, digestion, and analysis of selected heavy metals: lead .... research laboratory, University of Ibadan. Each ... Survey of consumption of waterleaf in Ota: Over 500 ..... In Encyclopedia of.

  16. urban dietary heavy metal intake from protein foods and vegetables

    African Journals Online (AJOL)

    Mgina

    Contamination of food and food products by heavy metals has made dietary intake as one of the ... metals cadmium, copper, lead and zinc from protein-foods (beans, meat, fish, milk) and green ..... on food additives Technical report series. No.

  17. Microbial and heavy metal contamination of pineapple products ...

    African Journals Online (AJOL)

    SAM

    Quantitative determination of heavy metals: zinc, iron, lead, copper, cadmium and aluminium ...... consumption of dairy products, fish/seafood and meat from Ismailia ... Contamination in Green Leafy Vegetables Grown in Bangalore Urban.

  18. Biomonitoring of heavy metals: Definitions, possibilities and limitations

    International Nuclear Information System (INIS)

    Markert, B.; Oehlmann, J.; Roth, M.

    2000-01-01

    Increasing attention given to heavy metals as components of the pollutant load in ecosystems makes it necessary to find reliable biological indicators. Fundamental investigations into the effect of heavy metals on organisms are therefore required. Different organisms (mosses, snails, etc.) were chosen as indicator organisms to optimize the indication of heavy metal loads at the physiological and biochemical level. All current programmes are designed to observe and measure pollutant inputs on a short or long-term basis. However, the changes in the environment of a phenological, physiological, sociological, genetic and physiological/biochemical nature have been investigated by biologists since the beginning of biological scientific research. So far excellent scientific results have been produced by qualification of the heavy metal status in ecosystems. Until now, the quantification of the results with regard to pollutant inputs in ecosystems (mass balances) and their action in these ecosystems have been investigated inadequately. (author)

  19. Estimation of Heavy Metals in Neem Tree Leaves along Katsina ...

    African Journals Online (AJOL)

    Michael Horsfall

    Key Words: Neem tree, Heavy metals, Pollution. Determination ... concentrations of pollutants in the tree bark correlate with those of ... hence are not readily detoxified and removed by .... levels can severely damage the brain and kidneys and.

  20. Distribution of Heavy Metals in Organs of Freshwater Fishes from ...

    African Journals Online (AJOL)

    MBI

    2015-12-24

    Dec 24, 2015 ... indicate that the concentrations of the heavy metals in the samples are generally well above the respective recommended ... weathering processes on rocks and soils (Babel and. Opiso ..... Source apportionment of suspended.

  1. Improving crop tolerance to heavy metal stress by polyamine application.

    Science.gov (United States)

    Soudek, Petr; Ursu, Marina; Petrová, Šárka; Vaněk, Tomáš

    2016-12-15

    Many areas have been heavily contaminated by heavy metals from industry and are not suitable for food production. The consumption of contaminated foods represents a health risk in humans, although some heavy metals are essential at low concentrations. Increasing the concentrations of essential elements in foods is one goal to improve nutrition. The aim of this study was to increase the accumulation of heavy metals in plant foods by the external application of putrescine. The levels of cadmium, zinc and iron were measured in different vegetables grown in hydroponic medium supplemented with heavy metals and compared with those grown in a reference medium. The estimated daily intake, based on the average daily consumption for various vegetable types, and the influence of polyamines on metal uptake were calculated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Heavy metals' data in soils for agricultural activities

    Directory of Open Access Journals (Sweden)

    T.A. Adagunodo

    2018-06-01

    Full Text Available In this article, the heavy metals in soils for agricultural activities were analyzed statistically. Ten (10 soil samples were randomly taken across the agricultural zones in Odo-Oba, southwestern Nigeria. Ten (10 metals; namely: copper (Cu, lead (Pb, chromium (Cr, arsenic (As, zinc (Zn, cadmium (Cd, nickel (Ni, antimony (Sb, cobalt (Co and vanadium (V were determined and compared with the guideline values. When the values were compared with the international standard, none of the heavy metals in the study area exceeded the threshold limit. However, the maximum range of the samples showed that Cr and V exceeded the permissible limit which could be associated with ecological risk. The data can reveal the distributions of heavy metals in the agricultural topsoil of Odo-Oba, and can be used to estimate the risks associated with the consumption of crops grown on such soils. Keywords: Agricultural soils, Heavy metals, Contamination, Environment, Soil screening, Geostatistics

  3. Rhizofiltration of heavy metals from the tannery sludge by the ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-10-20

    Oct 20, 2008 ... The accumulation of toxic metals in the plants was significantly increased, with increasing exposure time ..... in the conversion of organic carbon into carbon dioxide. It ... Once absorbed by the plants, toxic or heavy metals can.

  4. Natural occurrence of heavy metal, fungi and mycotoxins in soybean ...

    African Journals Online (AJOL)

    Yomi

    2011-12-16

    Dec 16, 2011 ... Heavy metals are a definite human health hazard be- cause of their .... The mean values of nutrient composition of the soybean meal samples ..... A food borne disease outbreak due to the consumption of moldy sorghum and.

  5. Heavy metal exposure in patients suffering from electromagnetic hypersensitivity

    International Nuclear Information System (INIS)

    Ghezel-Ahmadi, David; Engel, Alice; Weidemann, Joerg; Budnik, Lygia Therese; Baur, Xaver; Frick, Ulrich; Hauser, Simone; Dahmen, Norbert

    2010-01-01

    Background: Risks from electromagnetic devices are of considerable concern. Electrohypersensitive (EHS) persons attribute a variety of rather unspecific symptoms to the exposure to electromagnetic fields. The pathophysiology of EHS is unknown and therapy remains a challenge. Objectives: Heavy metal load has been discussed as a potential factor in the symptomatology of EHS patients. The main objective of the study was to test the hypothesis of a link between EHS and heavy metal exposure. Methods: We measured lead, mercury and cadmium concentrations in the blood of 132 patients (n = 42 males and n = 90 females) and 101 controls (n = 34 males and n = 67 females). Results: Our results show that heavy metal load is of no concern in most cases of EHS but might play a role in exceptional cases. Conclusions: The data do not support the general advice to heavy metal detoxification in EHS.

  6. Determination of heavy metals in chinese prickly ash from different ...

    African Journals Online (AJOL)

    digestion, and the contents of copper (Cu), nickel (Ni), chromium (Cr), lead (Pb), cadmium ... concentrations of heavy metals in these CPA samples mean they are safe for human consumption. ... poisoning, including Pb, Cd, As, Hg, Sn, and Sb.

  7. Preliminary Assessment of Heavy Metal Pollution of Opa Reservoir, Ile

    African Journals Online (AJOL)

    big timmy

    Awolowo University (OAU), Ile-Ife, Nigeria, with a view to assessing its pollution level. ... Heavy metals are not biodegradable, but are assimilated .... samples were filtered (with Whatman filter paper. No 42) and ..... acidity,Water, Air Soil Pollut.

  8. Accumulation of Proline under Salinity and Heavy metal stress in ...

    African Journals Online (AJOL)

    Michael Horsfall

    Seed germination and growth parameters of seedlings of cauliflower were observed after 5, 10 and 15 ... Keywords: Abiotic stress, salinity, proline and heavy metals. The responses of ..... induced accumulation of free proline in a metal-tolerant.

  9. Heavy metal pollution disturbs immune response in wild ant populations

    International Nuclear Information System (INIS)

    Sorvari, Jouni; Rantala, Liisa M.; Rantala, Markus J.; Hakkarainen, Harri; Eeva, Tapio

    2007-01-01

    Concern about the effects of environmental contaminants on immune function in both humans and wildlife is growing and practically nothing is known about this impact on terrestrial invertebrates, even though they are known to easily accumulate pollutants. We studied the effect of industrial heavy metal contamination on immune defense of a free-living wood ant (Formica aquilonia). To find out whether ants show an adapted immune function in a polluted environment, we compared encapsulation responses between local and translocated colonies. Local colonies showed higher heavy metal levels than the translocated ones but the encapsulation response was similar between the two groups, indicating that the immune system of local ants has not adapted to high contamination level. The encapsulation response was elevated in moderate whereas suppressed in high heavy metal levels suggesting higher risk for infections in heavily polluted areas. - Heavy metal pollution affects immune function in ants

  10. Cell surface engineering of microorganisms towards adsorption of heavy metals.

    Science.gov (United States)

    Li, Peng-Song; Tao, Hu-Chun

    2015-06-01

    Heavy metal contamination has become a worldwide environmental concern due to its toxicity, non-degradability and food-chain bioaccumulation. Conventional physical and chemical treatment methods for heavy metal removal have disadvantages such as cost-intensiveness, incomplete removal, secondary pollution and the lack of metal specificity. Microbial biomass-based biosorption is one of the approaches gaining increasing attention because it is effective, cheap, and environmental friendly and can work well at low concentrations. To enhance the adsorption properties of microbial cells to heavy metal ions, the cell surface display of various metal-binding proteins/peptides have been performed using a cell surface engineering approach. The surface engineering of Gram-negative bacteria, Gram-positive bacteria and yeast towards the adsorption of heavy metals are reviewed in this article. The problems and future perspectives of this technology are discussed.

  11. Heavy Metal Analyses and Nutritional Composition of Raw and ...

    African Journals Online (AJOL)

    PROF HORSFALL

    KEYWORDS: Nutritional composition, heavy metals, fresh water fishes, marine water fishes, lagoons. Introduction. Fish is an .... the flame and 90% passed out as waste. The flame ..... metals in surface water, sediments, fish and periwinkles of ...

  12. Trend of Heavy Metal Concentrations in Lagos Lagoon Ecosystem

    African Journals Online (AJOL)

    komla

    The distribution and occurrence of heavy metals in the sediment, water and benthic animals of the Lagos lagoon ... The concentrations of the metals detected in the lagoon sediment and water ..... waste products contaminating water sources.

  13. Heavy metal contamination of soil and sediment in Zambia

    African Journals Online (AJOL)

    USER

    Key words: Heavy metal, contamination, mining, soil, sediment. INTRODUCTION ... drinking water and inhaling air or soil contaminated by mining activities and the ..... indicates that copper waste discharged into the upper reaches of the Kafue ...

  14. Heavy metals, PAHs and toxicity in stormwater wet detention ponds

    DEFF Research Database (Denmark)

    Wium-Andersen, Tove; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild

    2011-01-01

    Concentrations of 6 different heavy metals and total Polycyclic Aromatic Hydrocarbons (PAH) were determined in stormwater runoff and in the pond water of two Danish wet detention ponds. The pond water samples were analyzed for toxic effects, using the algae Selenastrum capricornutum as a test...... organism. Stormwater and pond water from a catchment with light industry showed high levels of heavy metals, especially zinc and copper. The pond water showed high toxic effects and copper were found to be the main toxicant. Additionally, a large part of the copper was suspected to be complex bound......, reducing the potential toxicity of the metal. Another catchment (residential) produced stormwater and pond water with moderate concentration of heavy metals. The pond water occasionally showed toxic effects but no correlation between heavy metals and toxicity was identified. PAHs concentrations were...

  15. Baby Teeth Link Autism and Heavy Metals, NIH Study Suggests

    Science.gov (United States)

    ... Release Thursday, June 1, 2017 Baby teeth link autism and heavy metals, NIH study suggests Cross-section ... Sinai Health System Baby teeth from children with autism contain more toxic lead and less of the ...

  16. Heavy metal oxide glasses as gamma rays shielding material

    International Nuclear Information System (INIS)

    Kaur, Preet; Singh, Devinder; Singh, Tejbir

    2016-01-01

    The gamma rays shielding parameters for heavy metal oxide glasses and concrete samples are comparable. However, the transparent nature of glasses provides additional feature to visualize inside the shielding material. Hence, different researchers had contributed in computing/measuring different shielding parameters for different configurations of heavy metal oxide glass systems. In the present work, a detailed study on different heavy metal (_5_6Ba, _6_4Gd, _8_2Pb, _8_3Bi) oxide glasses has been presented on the basis of different gamma rays shielding parameters as reported by different researchers in the recent years. It has been observed that among the selected heavy metal oxide glass systems, Bismuth based glasses provide better gamma rays shielding. Hence, Bismuth based glasses can be better substitute to concrete walls at nuclear reactor sites and nuclear labs.

  17. Heavy metal oxide glasses as gamma rays shielding material

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Preet; Singh, Devinder; Singh, Tejbir, E-mail: dr.tejbir@gmail.com

    2016-10-15

    The gamma rays shielding parameters for heavy metal oxide glasses and concrete samples are comparable. However, the transparent nature of glasses provides additional feature to visualize inside the shielding material. Hence, different researchers had contributed in computing/measuring different shielding parameters for different configurations of heavy metal oxide glass systems. In the present work, a detailed study on different heavy metal ({sub 56}Ba, {sub 64}Gd, {sub 82}Pb, {sub 83}Bi) oxide glasses has been presented on the basis of different gamma rays shielding parameters as reported by different researchers in the recent years. It has been observed that among the selected heavy metal oxide glass systems, Bismuth based glasses provide better gamma rays shielding. Hence, Bismuth based glasses can be better substitute to concrete walls at nuclear reactor sites and nuclear labs.

  18. Heavy metal speciation and their accumulation in sediments of Lake ...

    African Journals Online (AJOL)

    UFUOMA

    African Journal of Environmental Science and Technology Vol. 5(4), pp. 280-298, April ..... present study gave higher values due to the effect of increasing ...... on The Heavy Metal. Pollution of Guanabara Bay Sediments and Evaluation of The.

  19. Biosorption of heavy metals by a marine bacterium

    International Nuclear Information System (INIS)

    Iyer, Anita; Mody, Kalpana; Jha, Bhavanath

    2005-01-01

    Heavy metal chelation property of exopolysaccharide produced by Enterobacter cloaceae, a marine bacterium, isolated from the West Coast of India, is reported in this paper. The exopolysaccharide demonstrated excellent chelating properties with respect to cadmium (65%) followed by copper (20%) and cobalt (8%) at 100 mg/l heavy metal concentration. However, it could not chelate mercury. A comparative study of the percentage biosorption of the above mentioned metals is presented here

  20. Biosorption of heavy metals by a marine bacterium

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Anita [Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, Gujarat (India); Mody, Kalpana [Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, Gujarat (India)]. E-mail: khmody@csmcri.org; Jha, Bhavanath [Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, Gujarat (India)

    2005-03-01

    Heavy metal chelation property of exopolysaccharide produced by Enterobacter cloaceae, a marine bacterium, isolated from the West Coast of India, is reported in this paper. The exopolysaccharide demonstrated excellent chelating properties with respect to cadmium (65%) followed by copper (20%) and cobalt (8%) at 100 mg/l heavy metal concentration. However, it could not chelate mercury. A comparative study of the percentage biosorption of the above mentioned metals is presented here.

  1. Leaching Properties of Naturally Occurring Heavy Metals from Soils

    Science.gov (United States)

    Zhang, M.; Hoshino, M.; Yoshikawa, M.; Hara, J.; Sugita, H.

    2014-12-01

    The major threats to human health from heavy metals are associated with exposure to arsenic, lead, cadmium, chromium, mercury, as well as some other elements. The effects of such heavy metals on human health have been extensively studied and reviewed by international organizations such as WHO. Due to their toxicity, heavy metal contaminations have been regulated by national environmental standards in many countries, and/or laws such as the Soil Contamination Countermeasures Act in Japan. Leaching of naturally occurring heavy metals from the soils, especially those around abandoned metal mines into surrounding water systems, either groundwater or surface water systems, is one of the major pathways of exposure. Therefore, understanding the leaching properties of toxic heavy metals from naturally polluted soils is of fundamentally importance for effectively managing abandoned metal mines, excavated rocks discharged from infrastructure constructions such as tunneling, and/or selecting a pertinent countermeasure against pollution when it is necessary. In this study, soil samples taken from the surroundings of abandoned metal mines in different regions in Japan were collected and analyzed. The samples contained multiple heavy metals such as lead, arsenic and chromium. Standard leaching test and sequential leaching test considering different forms of contaminants, such as trivalent and pentavalent arsenics, and trivalent and hexavalent chromiums, together with standard test for evaluating total concentration, X-ray Fluorescence Analysis (XRF), X-ray diffraction analysis (XRD) and Cation Exchange Capacity (CEC) tests were performed. In addition, sequential leaching tests were performed to evaluate long-term leaching properties of lead from representative samples. This presentation introduces the details of the above experimental study, discusses the relationships among leaching properties and chemical and mineral compositions, indicates the difficulties associated with

  2. Predictive Modelling of Heavy Metals in Urban Lakes

    OpenAIRE

    Lindström, Martin

    2000-01-01

    Heavy metals are well-known environmental pollutants. In this thesis predictive models for heavy metals in urban lakes are discussed and new models presented. The base of predictive modelling is empirical data from field investigations of many ecosystems covering a wide range of ecosystem characteristics. Predictive models focus on the variabilities among lakes and processes controlling the major metal fluxes. Sediment and water data for this study were collected from ten small lakes in the ...

  3. Heavy Metal Polluted Soils: Effect on Plants and Bioremediation Methods

    OpenAIRE

    Chibuike, G. U.; Obiora, S. C.

    2014-01-01

    Soils polluted with heavy metals have become common across the globe due to increase in geologic and anthropogenic activities. Plants growing on these soils show a reduction in growth, performance, and yield. Bioremediation is an effective method of treating heavy metal polluted soils. It is a widely accepted method that is mostly carried out in situ; hence it is suitable for the establishment/reestablishment of crops on treated soils. Microorganisms and plants employ different mechanisms for...

  4. Distribution of heavy metals from flue gas in algal bioreactor

    Science.gov (United States)

    Napan, Katerine

    Flue gas from coal-fired power plants is a major source of CO2 to the atmosphere. Microalgae can use this enriched form of CO2 as carbon source and in turn the biomass can be used to produce food, feed, fertilizer and biofuels. However, along with CO2, coal-based flue gas will inevitably introduce heavy metals, which have a high affinity to bind algal cells, could be toxic to the organisms and if transferred to the products could limit their uses. This study seeks to address the distribution and impact of heavy metals present in flue gas on microalgae production systems. To comprehend its effects, algae Scenedesmus obliquus was grown in batch reactors in a multimetal system. Ten heavy metals (Cu, Co, Zn, Pb, As, Se, Cr, Hg, Ni and Cd) were selected and were evaluated at four concentrations (1X, 2X, 5X and 10X). Results show that most heavy metals accumulated mainly in biomass and were found in very low concentrations in media. Hg was shown to be lost from the culture, with low amounts present in the biomass. An upper limit for As uptake was observed, suggesting its likelihood to build-up in the system during medium recycle. The As limited bioaccumulation was overcome by addition of sulfur to the algal medium. Heavy metal at 2X, 5X and 10X inhibited both growth and lipid production, while at the reference concentration both biomass and lipids yields were increased. Heavy metal concentrations in the medium and biomass were time dependent, and at the end of the cultivation most heavy metals in the supernatant solution complied with the recommendations for irrigation water, while biomass was below limits for cattle and poultry feed, fertilizer, plastic and paper. This research shows that bioremediation of CO2 and heavy metals in combination with energy production can be integrated, which is an environmentally friendly form of biotechnology.

  5. Process for removing heavy metal compounds from heavy crude oil

    Science.gov (United States)

    Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

    1991-01-01

    A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

  6. Antibiogram and heavy metal tolerance of bullfrog bacteria in Malaysia

    OpenAIRE

    Tee, L.W.; Najiah, M.

    2011-01-01

    Bacterial isolates from 30 farmed bullfrogs (Lithobates catesbeianus) weighing 500-600 g at Johore, Malaysia with external clinical signs of ulcer, red leg and torticollis were tested for their antibiograms and heavy metal tolerance patterns. A total of 17 bacterial species with 77 strains were successfully isolated and assigned to 21 antibiotics and 4 types of heavy metal (Hg2+, Cr6+, Cd2+, Cu2+). Results revealed that bacteria were resistant against lincomycin (92%), oleandomycin (72.7%) an...

  7. Heavy metals hazard in agriculture in NWFP

    International Nuclear Information System (INIS)

    Bhatti, A.; Perveen, S.

    2005-01-01

    Metals contamination is a persistent problem at many contaminated sites. In the U.S., the most commonly occurring metals at Superfund sites are lead, chromium, arsenic, zinc, cadmium, copper and mercury. The presence of metals in surface and ground waters, and soils can pose a significant threat to human health and ecological systems. Surface water and groundwater many be contaminated with metals from wastewater discharges or by direct contact with metals contaminated soils, sludges, mining wastes and debris. Due to use of sewage water and industrial effluents for agriculture in NWFP, there is a great threat to the human and animal health. In a survey of sewage water from three channels, it was found that 10 out of 18 samples ha lead content above the safe limits, while two in cadmium and 8 in chromium. While in soils irrigated with these channels, all the 18 samples were high in Cu and Pb, and 6 in Mn. As regards plants growing on these soils, samples of garlic, 4 of wheat and 3 of berseem were high in Pb. Cd content was high in 5 garlic samples, 5 wheat and 3 berseem. Effluents from two industries were high in Pb and four in Ni. In another study, all the nine water samples were high in Cu, 3 in Cd, and 6 in Pb. A survey of 20 Industries in Industrial Estate Hattar showed that all the effluent samples collected from these Industries were above the safe limits in Ni, Pb, Cd and Cr. From these studies, it seems that use of sewage water and industrial effluents for longer period can create heavy metals hazard in agriculture in NWFP. (author)

  8. Heavy metals binding properties of esterified lemon

    Energy Technology Data Exchange (ETDEWEB)

    Arslanoglu, Hasan; Altundogan, Hamdi Soner [Department of Chemical Engineering, Firat University, 23279 Elazig (Turkey); Tumen, Fikret, E-mail: ftumen@firat.edu.tr [Department of Chemical Engineering, Firat University, 23279 Elazig (Turkey)

    2009-05-30

    Sorption of Cd{sup 2+}, Cr{sup 3+}, Cu{sup 2+}, Ni{sup 2+}, Pb{sup 2+} and Zn{sup 2+} onto a carboxyl groups-rich material prepared from lemon was investigated in batch systems. The results revealed that the sorption is highly pH dependent. Sorption kinetic data indicated that the equilibrium was achieved in the range of 30-240 min for different metal ions and sorption kinetics followed the pseudo-second-order model for all metals studied. Relative sorption rate of various metal cations was found to be in the general order of Ni{sup 2+} > Cd{sup 2+} > Cu{sup 2+} > Pb{sup 2+} > Zn{sup 2+} > Cr{sup 3+}. The binding characteristics of the sorbent for heavy metal ions were analyzed under various conditions and isotherm data was accurately fitted to the Langmuir equation. The metal binding capacity order calculated from Langmuir isotherm was Pb{sup 2+} > Cu{sup 2+} > Ni{sup 2+} > Cd{sup 2+} > Zn{sup 2+} > Cr{sup 3+}. The mean free energy of metal sorption process calculated from Dubinin-Radushkevich parameter and the Polanyi potential was found to be in the range of 8-11 kJ mol{sup -1} for the metals studied showing that the main mechanism governing the sorption process seems to be ion exchange. The basic thermodynamic parameters of metals ion sorption process were calculated by using the Langmuir constants obtained from equilibration study. The {Delta}G{sup o} and {Delta}H{sup o} values for metals ion sorption on the lemon sorbent showed the process to be spontaneous and exothermic in nature. Relatively low {Delta}H{sup o} values revealed that physical adsorption significantly contributed to the mechanism.

  9. Study of heavy metals in urban runoff

    International Nuclear Information System (INIS)

    Nabizadeh, R.; Mahvi, A.; Mardani, G.; Yunesian, M.

    2005-01-01

    A cross-sectional survey was conducted through Tehran city and a field study was conducted to prepare main and accessory drainage channels map. Three main drainage channels were identified for this research and some sampling stations were chosen. Three stations selected in south of Tehran. The reason for selecting these stations is that all urban surface run off completely pass through these points and samples taken from these points are representative of all kinds of pollutants that transit from city surface. Another three stations were selected in center and further three stations were selected at north of Tehran. Surface runoff flow in three main channels, from north of south of Tehran, converge at south of Rey city and finally end up to Ghom Salt lake. The stations were chosen at three trajectories Sorkhe Hesar, Emad Avard, Kan. At each month two samples were from nine different stations. After collection of samples with respect to standard methods, they were dissolved in nitric acid and then analyzed by atomic absorption device. The results show that the concentrations of pollutants increased from north to south. For instance, Zinc had most concentration with monthly average of 0.98 mg/l and Nickel had the lowest amount with 0.02 mg/l in southern stations. Average concentration of Zn, Pb, Cd, Cu and Ni were: 0.638, 0.97, 0.04 and 0.035 mg/l respectively. Total average concentrations of heavy metals at three main channels were of 0.177, 0.176 and 0.145 mg/l. Emad Avard was the most polluted channel

  10. Effects of heavy metals on soil microbial community

    Science.gov (United States)

    Chu, Dian

    2018-02-01

    Soil is one of the most important environmental natural resources for human beings living, which is of great significance to the quality of ecological environment and human health. The study of the function of arable soil microbes exposed to heavy metal pollution for a long time has a very important significance for the usage of farmland soil. In this paper, the effects of heavy metals on soil microbial community were reviewed. The main contents were as follows: the effects of soil microbes on soil ecosystems; the effects of heavy metals on soil microbial activity, soil enzyme activities and the composition of soil microbial community. In addition, a brief description of main methods of heavy metal detection for soil pollution is given, and the means of researching soil microbial community composition are introduced as well. Finally, it is concluded that the study of soil microbial community can well reflect the degree of soil heavy metal pollution and the impact of heavy metal pollution on soil ecology.

  11. Heavy metal concentration of settled surface dust in residential building

    International Nuclear Information System (INIS)

    Nor Aimi abdul Wahab; Fairus Muhamad Darus; Norain Isa; Siti Mariam Sumari; Nur Fatihah Muhamad Hanafi

    2012-01-01

    The concentrations of heavy metals (Cu, Ni, Pb and Zn) in settled surface dust were collected from nine residential buildings in different areas in Seberang Prai Tengah District, Pulau Pinang. The samples of settled surface dust were collected in 1 m 2 area by using a polyethylene brush and placed in the dust pan by sweeping the living room floor most accessible to the occupants. Heavy metals concentrations were determined by using inductively coupled plasma optical emission spectrometer (ICP-OES) after digestion with nitric acid and sulphuric acid. The results show that the range of heavy metals observed in residential buildings at Seberang Prai Tengah were in the range of 2.20-14.00 mg/ kg, 1.50-32.70 mg/ kg, 1.50-76.80 mg/ kg and 14.60-54.40 mg/ kg for Cu, Ni, Pb and Zn respectively. The heavy metal concentration in the investigated areas followed the order: Pb > Zn > Ni > Cu. Statistical analysis indicates significant correlation between all the possible pairs of heavy metal. The results suggest a likely common source for the heavy metal contamination, which could be traced most probably to vehicular emissions, street dust and other related activities. (author)

  12. Multiple heavy metal removal using an entomopathogenic fungi Beauveria bassiana.

    Science.gov (United States)

    Gola, Deepak; Dey, Priyadarshini; Bhattacharya, Arghya; Mishra, Abhishek; Malik, Anushree; Namburath, Maneesh; Ahammad, Shaikh Ziauddin

    2016-10-01

    Towards the development of a potential remediation technology for multiple heavy metals [Zn(II), Cu(II), Cd(II), Cr(VI) and Ni(II)] from contaminated water, present study examined the growth kinetics and heavy metal removal ability of Beauveria bassiana in individual and multi metals. The specific growth rate of B. bassiana varied from 0.025h(-1) to 0.039h(-1) in presence of individual/multi heavy metals. FTIR analysis indicated the involvement of different surface functional groups in biosorption of different metals, while cellular changes in fungus was reflected by various microscopic (SEM, AFM and TEM) analysis. TEM studies proved removal of heavy metals via sorption and accumulation processes, whereas AFM studies revealed increase in cell surface roughness in fungal cells exposed to heavy metals. Present study delivers first report on the mechanism of bioremediation of heavy metals when present individually as well as multi metal mixture by entomopathogenic fungi. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Analysis and Pollution Assessment of Heavy Metal in Soil, Perlis

    International Nuclear Information System (INIS)

    Siti Norbaya Mat Ripin; Siti Norbaya Mat Ripin; Sharizal Hasan; Mohd Lias Kamal; NorShahrizan Mohd Hashim

    2014-01-01

    Concentration of 5 heavy metals (Cu, Cr, Ni, Cd, Pb) were studied in the soils around Perlis, to assess heavy metals contamination distribution due to industrialization, urbanization and agricultural activities. Soil samples were collected at depth of 0-15 cm in eighteen station around Perlis. The soil samples (2 mm) were obtained duplicates and subjected to hot block digestion and the concentration of total metal was determined via ICP-MS. Overall concentrations of Cu, Cr, Ni, Cd and Pb in the soil samples ranged from 0.38-240.59, 0.642-3.921, 0.689-2.398, 0-0.63 and 0.39-27.47 mg/ kg respectively. The concentration of heavy metals in the soil display the following decreasing trend: Cu> Pb> Cr> Ni> Cd. From this result, found that level of heavy metal in soil near centralized Chuping industrial areas give maximum value compared with other location in Perlis. The Pollution index revealed that only 11 % of Cu and 6 % of Cd were classes as heavily contaminated. Meanwhile, Cu and Pb showed 6 % from all samples result a moderately contaminated and the others element give low contamination. Results of combined heavy metal concentration and heavy metal assessment indicate that industrial activities and traffic emission represent most important sources for Cu, Cd and Pb whereas Cr, Ni mainly from natural sources. Increasing anthropogenic influences on the environment, especially pollution loadings, have caused negative changes in natural ecosystems and decreased biodiversity. (author)

  14. Selection of ectomycorrhizal willow genotype in phytoextraction of heavy metals.

    Science.gov (United States)

    Hrynkiewicz, Katarzyna; Baum, Christel

    2013-01-01

    Willow clones are used for the phytoextraction of heavy metals from contaminated soils and are usually mycorrhizal. The receptiveness of willow clones for mycorrhizal inoculum varies specific to genotype; however, it is unknown if this might have a significant impact on their efficiency in phytoextraction of heavy metals. Therefore, a model system with mycorrhizal and non-mycorrhizal willows of two different genotypes--one with usually stronger natural mycorrhizal colonization (Salix dasyclados), and one with lower natural mycorrhizal colonization (S. viminalis)--was investigated for its efficiency of phytoextraction of heavy metals (Cd, Pb, Cu, Zn) from contaminated soil. Inoculation with the ectomycorrhizal fungus Amanita muscaria significantly decreased the biomass of leaves of both inoculated willow clones, and increased or had no effect on the biomass of trunks and roots of S. dasyclados and S. viminalis, respectively. The concentrations of heavy metals in the biomass of S. dasyclados were in general higher than in S. viminalis irrespective of inoculation with the ectomycorrhizal fungus. Inoculation with A. muscaria significantly decreased the concentration of Cu in the trunks of both Salix taxa, but did not affected the concentrations of other heavy metals in the biomass. In conclusion, stronger receptiveness of willow clones for mycorrhizal inoculum was correlated with an increased total extraction of heavy metals from contaminated soils. Therefore, this seems to be a suitable criterion for effective willow clone selection for phytoremediation. Increased biomass production with relatively constant metal concentrations seems to be a major advantage of mycorrhizal formation of willows in phytoremediation of contaminated soils.

  15. Research on heavy metal pollution of river Ganga: A review

    Directory of Open Access Journals (Sweden)

    Dipak Paul

    2017-06-01

    Full Text Available River Ganga is considered sacred by people of India for providing life sustenance to environment and ecology. Anthropogenic activities have generated important transformations in aquatic environments during the last few decades. Advancement of human civilization has put serious questions to the safe use of river water for drinking and other purposes. The river water pollution due to heavy metals is one of the major concerns in most of the metropolitan cities of developing countries. These toxic heavy metals entering the environment may lead to bioaccumulation and biomagnifications. These heavy metals are not readily degradable in nature and accumulate in the animal as well as human bodies to a very high toxic amount leading to undesirable effects beyond a certain limit. Heavy metals in riverine environment represent an abiding threat to human health. Exposure to heavy metals has been linked to developmental retardation, kidney damage, various cancers, and even death in instances of very high exposure. The following review article presents the findings of the work carried out by the various researchers in the past on the heavy metal pollution of river Ganga.

  16. Assessment of Heavy Metal Pollution in Topsoil around Beijing Metropolis

    Science.gov (United States)

    Sun, Ranhao; Chen, Liding

    2016-01-01

    The topsoil around Beijing metropolis, China, is experiencing impacts of rapid urbanization, intensive farming, and extensive industrial emissions. We analyzed the concentrations of Cu, Ni, Pb, Zn, Cd, and Cr from 87 topsoil samples in the pre-rainy season and 115 samples in the post-rainy season. These samples were attributed to nine land use types: forest, grass, shrub, orchard, wheat, cotton, spring maize, summer maize, and mixed farmland. The pollution index (PI) of heavy metals was calculated from the measured and background concentrations. The ecological risk index (RI) was assessed based on the PI values and toxic-response parameters. The results showed that the mean PI values of Pb, Cr, and Cd were > 1 while those of Cu, Ni, and Zn were heavy metal concentrations and the impact of atmospheric transport on heavy metal concentrations varied according to the heavy metal types. The concentrations of Cu, Cd, and Cr decreased from the pre- to post-rainy season, while those of Ni, Pb, and Zn increased during this period. Future research should be focused on the underlying atmospheric processes that lead to these spatial and seasonal variations in heavy metals. The policymaking on environmental management should pay close attention to potential ecological risks of Cd as well as identifying the transport pathways of different heavy metals. PMID:27159454

  17. Electrodialytic removal of heavy metals from different fly ashes. Influence of heavy metal speciation in the ashes

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.; Villumsen, Arne

    2003-01-01

    Electrodialytic Remediation has recently been suggested as a potential method for removal of heavy metals from fly ashes. In this work electrodialytic remediation of three different fly ashes, i.e. two municipal solid waste incinerator (MSWI) fly ashes and one wood combustion fly ash was studied...... in lab scale, and the results were discussed in relation to the expected heavy metal speciation in the ashes. In initial leaching experiments the pH-dependent desorption characteristics of the heavy metals Cd, Pb, Zn and Cu were analogous in the two MSWI ashes, and thus it was expected......-moval efficiencies were observed, especially for Pb and Zn. Cd, the sole heavy metal of environmental concern in the wood ash, was found more tightly bonded in this ash than in the two MSWI ashes. It was suggested that complex Cd-silicates are likely phases in the wood ash whereas more soluble, condensed phases...

  18. Assessment of heavy metal removal technologies for biowaste by physico-chemical fractionation

    NARCIS (Netherlands)

    Veeken, A.H.M.; Hamelers, H.V.M.

    2003-01-01

    In the Netherlands, the heavy metal content of biowaste-compost frequently exceeds the legal standards for heavy metals. In order to assess heavy metal removal technologies, a physico-chemical fractionation scheme was developed to gain insight into the distribution of heavy metals (Cd, Cu, Pb and

  19. Fusion welding of Fe-added lap joints between AZ31B magnesium alloy and 6061 aluminum alloy by hybrid laser-tungsten inert gas welding technique

    International Nuclear Information System (INIS)

    Qi, Xiao-dong; Liu, Li-ming

    2012-01-01

    Highlights: → Hybrid Laser-TIG fusion welding technique was used for joining Mg to Al alloys. → Laser defocusing amount determined penetration depth inside Al alloy of joints. → The addition of Fe interlayer suppressed Mg-Al intermetallics greatly in joints. → A maximum joint strength with optimum thickness of Fe interlayer was obtained. → Excessive addition of Fe interlayer was adverse for the strength improvement. -- Abstract: AZ31B magnesium alloy and 6061-T6 aluminum alloy were lap joined together with the addition of Fe interlayer by fusion welding of hybrid laser-tungsten inert gas (TIG) technique. The influence of location of laser focal spot (LFS) on joint penetration depth and that of the depth on joint strength were investigated. The results showed that when the LFS was just on the surface of Al plate, the deepest penetration could be obtained, which contributed to the improvement of shear strength of Fe-added joints, but not to the elevation of the strength of Mg/Al direct joints. The addition of Fe interlayer suppressed massive production of Mg-Al intermetallics but produced Fe-Al intermetallics in the fusion zone of the joints, whose micro-hardness was extremely high and was also adverse for the enhancement of joint shear strength. The effect of Fe-interlayer thickness on the joint shear strength was also examined, and the maximum shear strength of Fe-added joint could achieve 100 MPa with 0.13 mm thick Fe interlayer. The fracture modes of 0.07 and 0.13 mm Fe-interlayer-added joints were both quasi-cleavage, while those of direct and 0.22 mm interlayer-added joints were completely cleavage. The theoretical shear strength of the Fe-added joints was also discussed.

  20. The influence of heavy metals on the production of extracellular polymer substances in the processes of heavy metal ions elimination.

    Science.gov (United States)

    Mikes, J; Siglova, M; Cejkova, A; Masak, J; Jirku, V

    2005-01-01

    Wastewaters from a chemical industry polluted by heavy metal ions represent a hazard for all living organisms. It can mean danger for ecosystems and human health. New methods are sought alternative to traditional chemical and physical processes. Active elimination process of heavy metals ions provided by living cells, their components and extracellular products represents a potential way of separating toxic heavy metals from industrial wastewaters. While the abilities of bacteria to remove metal ions in solution are extensively used, fungi have been recognized as a promising kind of low-cost adsorbents for removal of heavy-metal ions from aqueous waste sources. Yeasts and fungi differ from each other in their constitution and in their abilities to produce variety of extracellular polymeric substances (EPS) with different mechanisms of metal interactions. The accumulation of Cd(2+), Cr(6+), Pb(2+), Ni(2+) and Zn(2+) by yeasts and their EPS was screened at twelve different yeast species in microcultivation system Bioscreen C and in the shaking Erlenmayer's flasks. This results were compared with the production of yeast EPS and the composition of yeast cell walls. The EPS production was measured during the yeast growth and cell wall composition was studied during the cultivations in the shaking flasks. At the end of the process extracellular polymers and their chemical composition were isolated and amount of bound heavy metals was characterized. The variable composition and the amount of the EPS were found at various yeast strains. It was influenced by various compositions of growth medium and also by various concentrations of heavy metals. It is evident, that the amount of bound heavy metals was different. The work reviews the possibilities of usage of various yeast EPS and components of cell walls in the elimination processes of heavy metal ions. Further the structure and properties of yeasts cell wall and EPS were discussed. The finding of mechanisms mentioned

  1. Hybrid laser-TIG welding, laser beam welding and gas tungsten arc welding of AZ31B magnesium alloy

    International Nuclear Information System (INIS)

    Liu Liming; Wang Jifeng; Song Gang

    2004-01-01

    Welding of AZ31B magnesium alloy was carried out using hybrid laser-TIG (LATIG) welding, laser beam welding (LBW) and gas tungsten arc (TIG) welding. The weldability and microstructure of magnesium AZ31B alloy welded using LATIG, LBW and TIG were investigated by OM and EMPA. The experimental results showed that the welding speed of LATIG was higher than that of TIG, which was caught up with LBW. Besides, the penetration of LATIG doubles that of TIG, and was four times that of LBW. In addition, arc stability was improved in hybrid of laser-TIG welding compared with using the TIG welding alone, especially at high welding speed and under low TIG current. It was found that the heat affect zone of joint was only observed in TIG welding, and the size of grains in it was evidently coarse. In fusion zone, the equiaxed grains exist, whose size was the smallest welded by LBW, and was the largest by TIG welding. It was also found that Mg concentration of the fusion zone was lower than that of the base one by EPMA in three welding processes

  2. Method of fabricating thin-walled articles of tungsten-nickel-iron alloy

    Science.gov (United States)

    Hovis, Jr., Victor M.; Northcutt, Jr., Walter G.

    1982-01-01

    The present invention relates to a method for fabricating thin-walled high-density structures oftungsten-nickel-iron alloys. A powdered blend of the selected alloy constituents is plasma sprayed onto a mandrel having the desired article configuration. The sprayed deposit is removed from the mandrel and subjected to liquid phase sintering to provide the alloyed structure. The formation of the thin-walled structure by plasma spraying significantly reduces shrinkage, and cracking while increasing physical properties of the structure over that obtainable by employing previously known powder metallurgical procedures.

  3. Characterisation of heavy metal-bearing phases in stream sediments of the Meza River Valley, Slovenia, by means of SEM/EDS analysis

    International Nuclear Information System (INIS)

    Miler, M; Gosar, M

    2010-01-01

    Stream sediment reflects the rock structure of the catchment area, its geochemical characteristics and possible recent contamination upstream of the sampling point and thus, it is most frequently used in geochemical researches of heavy metal pollution. Stream sediment samples were collected along the Mez'a River and its tributaries and the Drava River, located in the NNE part of Slovenia. Previous geochemical studies have shown that these sediments are heavily polluted with heavy metals as a consequence of past mining of Pb-Zn ore and steelworks activities. Conventional geochemical analyses (ICP-MS, AAS, etc.) provided limited information on mineralogy, morphology and sources of heavy metal-bearing phases therefore SEM/EDS was utilized. Several problems were confronted with during EDS analysis, which are related to identification and quantification of light elements, identification of elements due to peak overlaps and quantification of spectra from unpolished samples. These problems were successfully dealt with. SEM/EDS enabled successful identification of heavy metal-bearing phases in stream sediments. Ore mineral phases, such as cerussite, sphalerite, smithsonite and galena, different heavy metal-bearing Fe-alloys, Fe-oxides and spherical particles and common rock-forming and accessory mineral phases, such as barite, rutile, ilmenite, zircon and monazite, were identified using solely SEM/EDS. These results were used for subsequent geochemical interpretation and source apportionment of heavy metals, according to associations of different heavy metal-bearing phases. Heavy metal-bearing phases were arranged by their source and genesis into three groups, denoted as geogenic/technogenic, technogenic and geogenic.

  4. Characterisation of heavy metal-bearing phases in stream sediments of the Meža River Valley, Slovenia, by means of SEM/EDS analysis

    Science.gov (United States)

    Miler, M.; Gosar, M.

    2010-02-01

    Stream sediment reflects the rock structure of the catchment area, its geochemical characteristics and possible recent contamination upstream of the sampling point and thus, it is most frequently used in geochemical researches of heavy metal pollution. Stream sediment samples were collected along the Meža River and its tributaries and the Drava River, located in the NNE part of Slovenia. Previous geochemical studies have shown that these sediments are heavily polluted with heavy metals as a consequence of past mining of Pb-Zn ore and steelworks activities. Conventional geochemical analyses (ICP-MS, AAS, etc.) provided limited information on mineralogy, morphology and sources of heavy metal-bearing phases therefore SEM/EDS was utilized. Several problems were confronted with during EDS analysis, which are related to identification and quantification of light elements, identification of elements due to peak overlaps and quantification of spectra from unpolished samples. These problems were successfully dealt with. SEM/EDS enabled successful identification of heavy metal-bearing phases in stream sediments. Ore mineral phases, such as cerussite, sphalerite, smithsonite and galena, different heavy metal-bearing Fe-alloys, Fe-oxides and spherical particles and common rock-forming and accessory mineral phases, such as barite, rutile, ilmenite, zircon and monazite, were identified using solely SEM/EDS. These results were used for subsequent geochemical interpretation and source apportionment of heavy metals, according to associations of different heavy metal-bearing phases. Heavy metal-bearing phases were arranged by their source and genesis into three groups, denoted as geogenic/technogenic, technogenic and geogenic.

  5. Effect of post-weld heat treatment and electrolytic plasma processing on tungsten inert gas welded AISI 4140 alloy steel

    International Nuclear Information System (INIS)

    Dewan, Mohammad W.; Liang, Jiandong; Wahab, M.A.; Okeil, Ayman M.

    2014-01-01

    Highlights: • The effects of PWHT and EPP were explored on TIG welded AISI4140 alloy steel. • All welded samples were checked with PAUT and ensured defect-free before testing. • Residual stresses, hardness, and tensile properties were measured experimentally. • PWHT resulted higher ductility but lower tensile strength for grain refinement. • EPP-treated samples showed higher tensile strength but lower ductility. - Abstract: Post-weld heat treatment (PWHT) is commonly adopted on welded joints and structures to relieve post-weld residual stresses; and restore the mechanical properties and structural integrity. An electrolytic plasma process (EPP) has been developed to improve corrosion behavior and wear resistance of structural materials; and can be employed in other applications and surface modifications aspects. In this study the effects of PWHT and EPP on the residual stresses, micro-hardness, microstructures, and uniaxial tensile properties are explored on tungsten inert gas (TIG) welded AISI-4140 alloys steel with SAE-4130 chromium–molybdenum alloy welding filler rod. For rational comparison all of the welded samples are checked with nondestructive Phased Array Ultrasonic Testing (PAUT) and to ensure defect-free samples before testing. Residual stresses are assessed with ultrasonic testing at different distances from weld center line. PWHT resulted in relief of tensile residual stress due to grain refinement. As a consequence higher ductility but lower strength existed in PWHT samples. In comparison, EPP-treated samples revealed lower residual stresses, but no significant variation on the grain refinement. Consequently, EPP-treated specimens exhibited higher tensile strength but lower ductility and toughness for the martensitic formation due to the rapid heating and quenching effects. EPP was also applied on PWHT samples, but which did not reveal any substantial effect on the tensile properties after PWHT at 650 °C. Finally the microstructures and

  6. Transformation of heavy metals in lignite during supercritical water gasification

    International Nuclear Information System (INIS)

    Chen, Guifang; Yang, Xinfei; Chen, Shouyan; Dong, Yong; Cui, Lin; Zhang, Yong; Wang, Peng; Zhao, Xiqiang; Ma, Chunyuan

    2017-01-01

    Highlights: • The transformations of heavy metals during lignite SCWG were investigated. • The risks of heavy metals in lignite and residues after SCWG were evaluated. • The effects of experimental conditions on corrosion during SCWG were studied. - Abstract: Transformation characteristics of heavy metals during lignite supercritical water gasification (SCWG) were studied. A sequential extraction procedure (modified Tessier method) was used to selectively extract different fractions of Pb, Cd, Cr, Mn, Cu, Ni, and Zn. Heavy metals transformed into more stable fractions after SCWG. For Pb, Cd, Mn, Cu, and Zn, SCWG reduced the bioavailability and the risks posed by heavy metals in lignite. Under the experimental conditions, the conversion rates for Pb and Cd were 16.0%–25.2% and 16.3%–23.4%, respectively, whereas those for Mn, Cu, and Zn were much lower. Solid products enriched with Pb, Cd, Mn, Cu, and Zn were obtained after SCWG; the contents of these metals varied slightly in the liquid products under different experimental conditions. Excess Cr and Ni that did not originate from lignite were found in the residues, owing to reactor corrosion during lignite SCWG. Higher temperatures alleviated corrosion, whereas higher pressures and equivalence ratios (ER) had the opposite effect. None of the heavy metals were detected in the gas phase under the experimental conditions used in the present study. The correlation between the distributions of heavy metals and the experimental conditions were also studied. The transformation pathways of Pb, Cd, Mn, Cu, and Zn during SCWG were deduced according to the experimental results.

  7. Heavy metal sensitivity and bioconcentration in oribatid mites (Acari, Oribatida)

    Energy Technology Data Exchange (ETDEWEB)

    Skubala, Piotr, E-mail: piotr.skubala@us.edu.pl [Department of Ecology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Zaleski, Tomasz [Department of Soil Science and Soil Protection, Agricultural University in Krakow, Mickiewicza 21, 31-120 Cracow (Poland)

    2012-01-01

    In this study we aimed to identify different reactions of oribatid species to heavy metal pollution and to measure concentrations of cadmium, zinc and copper in oribatid species sampled along a gradient. Oribatid mites were sampled seasonally during two years in five meadows located at different distances from the zinc smelter in the Olkusz District, southern Poland. Oribatids were shown to withstand critical metal concentration and established comparatively abundant and diverse communities. The highest abundance and species richness of oribatids were recorded in soils with moderate concentrations of heavy metals. Four different responses of oribatid species to heavy metal pollution were recognized. Heavy metals (Zn, Pb, Cd, Ni) and various physical (bulk density, field capacity, total porosity) and chemical (K{sub av}, P{sub av}, N, C, pH) factors were recognized as the structuring forces that influence the distribution of oribatid species. Analysis by atomic absorption spectrophotometry revealed large differences in metal body burdens among species. None of the species can be categorized as accumulators or non-accumulators of the heavy metals - the pattern depends on the metal. The process of bioconcentration of the toxic metal (regulated) and essential elements (accumulated) was generally different in the five oribatid species studied. - Highlights: Black-Right-Pointing-Pointer Responses of oribatid mites to metal contamination along a gradient in meadow soils were studied. Black-Right-Pointing-Pointer Small concentrations of heavy metals positively influenced the abundance of oribatid mites. Black-Right-Pointing-Pointer Four different responses of oribatid species to heavy metal pollution were recognised. Black-Right-Pointing-Pointer Bioaccumulation of the toxic metal and essential elements proceeded differently in oribatid species. Black-Right-Pointing-Pointer Five studied oribatid species were deconcentrators of cadmium.

  8. Novel polymer-based nanocomposites for application in heavy metal pollution remediation

    CSIR Research Space (South Africa)

    Kotzé-Jacobs, L

    2012-10-10

    Full Text Available and kidney damage and also cancer ? Heavy metals can accumulate in food sources through heavy metal contamination of soil and plants ? CSIR 2012 Slide 3 Removal of heavy metals ? Small volume applications: ion exchange ? Larger volumes eg. acid mine... pollution, treatment shortfalls at municipalities and contaminated surface water discharges ? Accumulation of heavy metals and endocrine disrupters ? CSIR 2012 Slide 2 Introduction: Heavy metals ? Cr, Ni, Cu, Pb, As etc. ? Exposure can cause liver...

  9. The Role of the Component Metals in the Toxicity of Military-Grade Tungsten Alloy

    Directory of Open Access Journals (Sweden)

    Christy A. Emond

    2015-12-01

    Full Text Available Tungsten-based composites have been recommended as a suitable replacement for depleted uranium. Unfortunately, one of these mixtures composed of tungsten (W, nickel (Ni and cobalt (Co induced rhabdomyosarcomas when implanted into the leg muscle of laboratory rats and mice to simulate a shrapnel wound. The question arose as to whether the neoplastic effect of the mixture could be solely attributed to one or more of the metal components. To investigate this possibility, pellets with one or two of the component metals replaced with an identical amount of the biologically-inert metal tantalum (Ta were manufactured and implanted into the quadriceps of B6C3F1 mice. The mice were followed for two years to assess potential adverse health effects. Implantation with WTa, CoTa or WNiTa resulted in decreased survival, but not to the level reported for WNiCo. Sarcomas in the implanted muscle were found in 20% of the CoTa-implanted mice and 5% of the WTa- and WCoTa-implanted rats and mice, far below the 80% reported for WNiCo-implanted mice. The data obtained from this study suggested that no single metal is solely responsible for the neoplastic effects of WNiCo and that a synergistic effect of the three metals in tumor development was likely.

  10. EDGA amendment of slightly heavy metal loaded soil affects heavy metal solubility, crop growth and microbivorous nematodes but not bacteria and herbivorous nematodes

    NARCIS (Netherlands)

    Bouwman, L.A.; Bloem, J.; Römkens, P.F.A.M.; Japenga, J.

    2005-01-01

    Phytoextraction of heavy metals is a promising technology to remediate slightly and moderately contaminated soils. To enhance crops' uptake of heavy metals, chelates such as EDGA are being tested as soil additives. Heavy metal loaded EDGA can affect soil organisms such as bacteria and nematodes in

  11. Source of atmospheric heavy metals in winter in Foshan, China.

    Science.gov (United States)

    Tan, Ji-Hua; Duan, Jing-Chun; Ma, Yong-Liang; Yang, Fu-Mo; Cheng, Yuan; He, Ke-Bin; Yu, Yong-Chang; Wang, Jie-Wen

    2014-09-15

    Foshan is a ceramics manufacturing center in the world and the most polluted city in the Pearl River Delta (PRD) in southern China measured by the levels of atmospheric heavy metals. PM2.5 samples were collected in Foshan in winter 2008. Among the 22 elements and ions analyzed, 7 heavy metals (Zn, V, Mn, Cu, As, Cd and Pb) were studied in depth for their levels, spatiotemporal variations and sources. The ambient concentrations of the heavy metals were much higher than the reported average concentrations in China. The levels of Pb (675.7 ± 378.5 ng/m(3)), As (76.6 ± 49.1 ng/m(3)) and Cd (42.6 ± 45.2 ng/m(3)) exceeded the reference values of NAAQS (GB3095-2012) and the health guidelines of the World Health Organization. Generally, the levels of atmospheric heavy metals showed spatial distribution as: downtown site (CC, Chancheng District)>urban sites (NH and SD, Nanhai and Shunde Districts)>rural site (SS, Shanshui District). Two sources of heavy metals, the ceramic and aluminum industries, were identified during the sampling period. The large number of ceramic manufactures was responsible for the high levels of atmospheric Zn, Pb and As in Chancheng District. Transport from an aluminum industry park under light north-west winds contributed high levels of Cd to the SS site (Shanshui District). The average concentration of Cd under north-west wind was 220 ng/m(3), 20.5 times higher than those under other wind directions. The high daily maximum enrichment factors (EFs) of Cd, Pb, Zn, As and Cu at all four sites indicated extremely high contamination by local emissions. Back trajectory analysis showed that the heavy metals were also closely associated with the pathway of air mass. A positive matrix factorization (PMF) method was applied to determine the source apportionment of these heavy metals. Five factors (industry including the ceramic industry and coal combustion, vehicle emissions, dust, transportation and sea salt) were identified and industry was the most

  12. Tungsten-zirconium carbide-rhenium alloys with extraordinary thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X.D. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Xie, Z.M.; Miao, S. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Liu, R.; Jiang, W.B. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhang, T., E-mail: zhangtao@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wang, X.P., E-mail: xpwang@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Fang, Q.F. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Liu, C.S., E-mail: csliu@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Luo, G.N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Liu, X. [Southwest Institute of Plasma Physics, Chengdu (China)

    2016-05-15

    The low recrystallization temperature (1200 °C) of pure W is a serious limitation for application as facing plasma materials in fusion reactor. In this paper, W-0.5wt.%ZrC-1wt.%Re (WZR) alloy with recrystallization temperature up to 1800 °C was prepared by mechanical milling and spark plasma sintering. The grain size of WZR alloy is about 2.6 μm, smaller than that of pure W (4.4 μm), which keeps unchanged until the annealing temperature increases to 1800 °C. Tensile tests indicate that the WZR alloys exhibit excellent comprehensive properties: the ductile to brittle transition temperature of WZR is in the range from 400 °C to 500 °C, about 200 °C lower than that of pure W prepared by the same process; the total elongation (TE) of WZR at 600 °C is above 30%, which is about 2 times that of pure W (at 700 °C). Meanwhile its tensile strength keeps ∼450 MPa before and after 1800 °C annealing as well as its TE increases after annealing. WZR alloy exhibits higher hardness (489HV) than that of pure W (453HV) at room temperature. Microstructure analysis indicates that the strengthening of nano-sized ZrC particles dispersion and Re solid solution improve tensile properties and thermal stability of WZR alloy.

  13. Electrokinetic treatment of an agricultural soil contaminated with heavy metals.

    Science.gov (United States)

    Figueroa, Arylein; Cameselle, Claudio; Gouveia, Susana; Hansen, Henrik K

    2016-07-28

    The high organic matter content in agricultural soils tends to complex and retain contaminants such as heavy metals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co(+2), Zn(+2), Cd(+2), Cu(+2), Cr(VI), Pb(+2) and Hg(+2). The unenhanced electrokinetic treatment was not able to remove heavy metals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavy metals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavy metals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavy metals in the center of the soil specimen.

  14. Characterization of landfill leachates and studies on heavy metal removal.

    Science.gov (United States)

    Ceçen, F; Gürsoy, G

    2000-10-01

    This study covers a thorough characterisation of landfill leachates emerging from a sanitary landfill area. The landfill leachates were obtained in the acidic stage of landfill stabilisation. Their organic content was high as reflected by the high BOD5 (5 day biological oxygen demand) and COD (chemical oxygen demand) values. They were also highly polluted in terms of the parameters TKN (total Kjeldahl nitrogen), NH4-N, alkalinity, hardness and heavy metals. Nickel was present in these wastewaters at a significant concentration. With regard to the high heavy metal content of these wastewaters, several physicochemical removal alternatives for the heavy metals Cu, Pb, Zn, Ni, Cd, Cr, Mn and Fe were tested using coagulation, flocculation, precipitation, base addition and aeration. Additionally, COD removal and ammonia stripping were examined. Co-precipitation with either alum or iron salts did not usually lead to significantly higher heavy metal removal than lime alone. The major methods leading to an effective heavy metal removal were aeration and lime addition. Nickel and cadmium seemed to be strongly complexed and were not removed by any method. Also lead removal proved to be difficult. The results are also discussed in terms of compliance with standards.

  15. Assessment of heavy metal contents of green leafy vegetables

    Directory of Open Access Journals (Sweden)

    V. Jena

    2013-01-01

    Full Text Available Vegetables are rich sources of vitamins, minerals, and fibers, and have beneficial antioxidative effects. Ingestion of vegetables containing heavy metals is one of the main routes through which these elements enter the human body. Slowly released into the body, however, heavy metals can cause an array of diseases. In this study we investigated the concentrations of copper, chromium, zinc, and lead in the most frequently consumed vegetables including Pimpinella anisum, Spinacia oleracea, Amaranthus viridis, Coriandrum sativum, and Trigonella foenum graecum in various sites in Raipur city, India. Atomic absorption spectrophotometry was used to estimate the levels of these metals in vegetables. The mean concentration for each heavy metal in the samples was calculated and compared with the permissible levels set by the Food and Agriculture Organization and World Health Organization. The intake of heavy metals in the human diet was also calculated to estimate the risk to human health. Our findings indicated the presence of heavy metals in vegetables in the order of Cr > Zn > Cu > Pb. Based on these findings, we conclude that the vegetables grown in this region are a health hazard for human consumption.

  16. Elimination of radionuclides and heavy metals from soils

    International Nuclear Information System (INIS)

    Navarcik, I.; Cipakova, A.; Palagyl, S.

    1994-01-01

    Sorption and desorption of radionuclides and heavy metals, their vertical migration and gradual extraction from soils were studied. Tessier sequential extraction method was used for determination the physicochemical forms of radionuclides and heavy metals absorbed by root system of plants and leached into ground water. Fixed forms of heavy metals and radionuclides are prevailing in soils. As to artificial ( 90 Sr, 137 Cs) isotope ratio of fixed forms bound with soil components, it is higher for 137 Cs (black earth - 95%, sandy soil - 62%) as compared to 90 Sr. Mobilization procedures for elimination of unfavourable influence of these pollutants in soils were used. The bacteria Pseudomonas sp. and Micrococcus l. are applied for this purpose. At the same time the growing of technical plants (Linum usitatissimum L. and Brassica napus L. var.) was studied as a method for mobilizing the heavy metals and radionuclides from soils. Retardation influence of bacteria on 85 Sr was noticed after as much as 3 months. The sum of water-soluble and exchangeable fractions reached 60%. Values of Cs distribution proved that microorganisms or plants used had no appreciable influence on Cs-mobility. After 3 months the relative ratio of accessible fraction increased with about 5%. As to heavy metals, both bacteria and plant growing influenced their retardation. In the case of Cd, one month operation of microorganisms resulted in important increase of easily available Cd-ratio (about 25%) in soils. (author)

  17. Immunotoxicology in wood mice along a heavy metal pollution gradient

    International Nuclear Information System (INIS)

    Tersago, Katrien; De Coen, Wim; Scheirs, Jan; Vermeulen, Katrien; Blust, Ronny; Bockstaele, Dirk van; Verhagen, Ron

    2004-01-01

    We carried out an immunotoxicological field study of wood mice in three populations along a heavy metal pollution gradient. Heavy metal concentrations in liver tissue indicated that exposure to silver, arsenic, cadmium, cobalt and lead decreased with increasing distance from a non-ferrous smelter. Host resistance to the endoparasite Heligmosomoides polygyrus decreased with increasing exposure, while the abundance of tick larvae and the nematode Syphacia stroma was unrelated to heavy metal exposure. Spleen mass was increased at the intermediate and the most polluted sites and was positively correlated with the number of H. polygyrus and tick larvae. Proportion of early apoptotic leukocytes increased towards the smelter and was positively related to cadmium exposure. Red and white blood cell counts and lysozyme activity showed no relationship with metal exposure. All together, our observations suggest negative effects of heavy metal exposure on the immune function of wood mice under field conditions. - Capsule: Complex interactions among metal burden, immune response and parasite burden suggest negative effects of heavy metal exposure on the immune system of wood mice

  18. Heavy metal accumulation by carrageenan and agar producing algae

    Energy Technology Data Exchange (ETDEWEB)

    Burdin, K.S. [Moscow State Univ. (Russian Federation). Faculty of Biology; Bird, K.T. [North Carolina Univ., Wilmington, NC (United States). Center for Marine Science Research

    1994-09-01

    The accumulation of six heavy metals Cu, Cd, Ni, Zn, Mn and Pb was measured in living and lzophilized algal thalli. The agar producing algae were Gracilaria tikvahiae and Gelidium pusillum. The carrageenan producing macroalgae were Agardhiella subulata and the gametophyte and tetrasporophyte phases of Chondrus crispus. These produce primarily iota, kappa and lambda carrageenans, respectively. At heavy metal concentrations of 0.5 mg L{sup -1}, living thalli of Gracilaria tikvahiae generally showed the greatest amount of accumulation of the 6 heavy metals tested. The accumulation of Pb was greater in the living thalli of all four species than in the lyophilized thalli. Except for Agardhiella subulata, lyophilized thalli showed greater accumulation of Ni, Cu and Zn. There was no difference in heavy metal accumulation between living and lyophilized thalli in the accumulation of Cd. Manganese showed no accumulation at the tested concentration. There did not appear to be a relationship between algal hydrocolloid characteristics and the amounts of heavy metals accumulated. (orig.)

  19. Heavy metals effect in Drosophila melanogaster germinal cells

    International Nuclear Information System (INIS)

    Rosa Duque de la, M.E.

    1984-01-01

    Heavy metals occur naturally and some of them are very important in cellular metabolism. Industrial development has increased metal concentration in the environment and in the living organisms tissues. This increase promotes the human risk to suffer teratogenesis, carcinogenesis and mutagenesis. Different biological systems have been used to proof the genetic effect of heavy metals including Drosophila. In the present work chromium, cadmium, lead, zinc and arsenic salts were administered to Drosophila females and males adults in order to determine the genetic effect produced by these compounds, in both femenine and masculine germinal cells. The mating system used (''Oster males'' and y 2 wsup(a)/y 2 wsup(a); e/e females) permited to determine among two succesive generations, the mutagenic effects produced by heavy metals in Drosophila. The salts administration to adult flies was made by injection. Non-disjunction, X-chromosome loss, and sex linked recessive lethals frequency was increased by heavy metals. It was observed a fertility disminution between F 1 descendants from individuals treated with the metalic salts. It was demonstrated that heavy metals can interact with genetic material at different levels in the two types of gametic cells to produce genetic damage. (author)

  20. Heavy metal content of combustible municipal solid waste in Denmark.

    Science.gov (United States)

    Riber, Christian; Fredriksen, Gry S; Christensen, Thomas H

    2005-04-01

    Data on the heavy metal composition of outlets from Danish incinerators was used to estimate the concentration of Zn, Cu, Pb, Cr, Ni, Cd, As and Hg in combustible waste (wet as received) at 14 Danish incinerators, representing about 80% of the waste incinerated in Denmark. Zn (1020 mg kg(-1)), Cu (620 mg kg(-1)) and Pb (370 mg kg(-1)) showed the highest concentration, whereas Hg (0.6 mg kg(-1)) showed the lowest concentration. The variation among the incinerators was in most cases within a factor of two to three, except for Cr that in two cases showed unexplained high concentrations. The fact that the data represent many incinerators and, in several cases, observations from a period of 4 to 5 years provides a good statistical basis for evaluating the content of heavy metals in combustible Danish waste. Such data may be used for identifying incinerators receiving waste with high concentrations of heavy metals suggesting the introduction of source control, or, if repeated in time, the data must also be used for monitoring the impacts of national regulation controlling heavy metals. It is recommended that future investigations consider the use of sample digestion methods that ensure complete digestion in order to use the data for determining the total heavy metal content of waste.

  1. Biosorption of heavy metals from wastewater by biosolids

    Energy Technology Data Exchange (ETDEWEB)

    Orhan, Y.; Bueyuekguengoer, H. [Ondokuz Mayis University, Engineering Faculty, Environmental Engineering Department, 55139 Samsun (Turkey); Hrenovic, J. [University of Zagreb, Faculty of Science, Department of Biology, Rooseveltov trg 6, 10000 Zagreb (Croatia)

    2006-08-15

    In a study where the removal of heavy metals from wastewater is the primary aim, the biosorption of heavy metals onto biosolids prepared as Pseudomonas aeruginosa immobilized onto granular activated carbon was investigated in batch and column systems. In the batch system, adsorption equilibriums of heavy metals were reached between 20 and 50 min, and the optimal dosage of biosolids was 0.3 g/L. The biosorption efficiencies were 84, 80, 79, 59 and 42 % for Cr(VI), Ni(II), Cu(II), Zn(II) and Cd(II) ions, respectively. The rate constants of biosorption and pore diffusion of heavy metals were 0.013-0.089 min{sup -1} and 0.026-0.690 min{sup -0.5}. In the column systems, the biosorption efficiencies for all heavy metals increased up to 81-100 %. The affinity of biosorption for various metal ions towards biosolids was decreased in the order: Cr = Ni > Cu > Zn > Cd. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  2. Stabilization of heavy metals in Tehran agricultural land

    International Nuclear Information System (INIS)

    Torabian, A.; Sadeghi, Sh.

    2001-01-01

    In order to prevent contamination of heavy metals accumulation in soil, plant, and ground water, several methods of prevention are studied, and tested worldwide. One of the method which has not been studied and applied in Iran is stabilization of heavy metals in soil by using clay minerals. Clay minerals due to hydration properties can adsorb organic and inorganic substances. Two clay minerals were used in this research: Bentonite with chemical structure of 2 to 1 (Two layers of silica and one layer of Aluminium) with CEC equal to 85 m eq/100 grams and Kao line with chemical structure of one to one (one layer silica and one layer Aluminum) and CEC=3 m eq/100 grams of soil. The physical and chemical properties of these two kinds of clays were different. Stabilization of heavy metals with different percentages of these two clays (7%, 15%, 22%) with different p H (4,7,8,11.5) were studied. The results indicate that with increasing of stabilizing agent at p H=7.8 and greater, stabilization of heavy metals increased significantly. The results also indicate the stabilization of heavy metals decreased rapidly at p H 4 and lower. The results of this study agree with the work of pervious researchers

  3. Electronic structure of indium-tungsten-oxide alloys and their energy band alignment at the heterojunction to crystalline silicon

    Science.gov (United States)

    Menzel, Dorothee; Mews, Mathias; Rech, Bernd; Korte, Lars

    2018-01-01

    The electronic structure of thermally co-evaporated indium-tungsten-oxide films is investigated. The stoichiometry is varied from pure tungsten oxide to pure indium oxide, and the band alignment at the indium-tungsten-oxide/crystalline silicon heterointerface is monitored. Using in-system photoelectron spectroscopy, optical spectroscopy, and surface photovoltage measurements, we show that the work function of indium-tungsten-oxide continuously decreases from 6.3 eV for tungsten oxide to 4.3 eV for indium oxide, with a concomitant decrease in the band bending at the hetero interface to crystalline silicon than indium oxide.

  4. A first-principles investigation of interstitial defects in dilute tungsten alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gharaee, Leili; Erhart, Paul, E-mail: erhart@chalmers.se

    2015-12-15

    The thermodynamic properties of intrinsic and extrinsic (Ti, V, Zr, Nb, Hf, Ta, Re) defects in tungsten have been investigated using density functional theory calculations. The formation energies of substitutional defects are discussed with respect to their thermodynamic solubility limits. Several different interstitial configurations have been identified as local minima on the potential energy surface. In addition to dumbbell configurations with orientations along 〈111〉 and 〈110〉, a lower symmetry configuration is described, which is referred to as a bridge interstitial. This interstitial type is found to be the lowest energy configuration for mixed-interstitials containing Ti, V, and Re, and can be up to 0.2 eV lower in energy than the other configurations. According to the calculations Ti, V and Re also trap self-interstitial atoms, which can be produced in substantial numbers during ion irradiation, affecting the mobility of the latter.

  5. Heavy metal ion adsorption onto polypyrrole-impregnated porous carbon.

    Science.gov (United States)

    Choi, Moonjung; Jang, Jyongsik

    2008-09-01

    Polypyrrole-impregnated porous carbon was readily synthesized using vapor infiltration polymerization of pyrrole monomers. The results show that the functionalized polymer layer was successfully coated onto the pore surface of carbon without collapse of mesoporous structure. The modified porous carbon exhibited an improved complexation affinity for heavy metal ions such as mercury, lead, and silver ions due to the amine group of polypyrrole. The introduced polypyrrole layer could provide the surface modification to be applied for heavy metal ion adsorbents. Especially, polymer-impregnated porous carbon has an enhanced heavy metal ion uptake, which is 20 times higher than that of adsorbents with amine functional groups. Furthermore, the relationship between the coated polymer amount and surface area was also investigated in regard to adsorption capacity.

  6. Effect of Heavy Metals in Plants of the Genus Brassica

    Science.gov (United States)

    Mourato, Miguel P.; Moreira, Inês N.; Leitão, Inês; Pinto, Filipa R.; Sales, Joana R.; Louro Martins, Luisa

    2015-01-01

    Several species from the Brassica genus are very important agricultural crops in different parts of the world and are also known to be heavy metal accumulators. There have been a large number of studies regarding the tolerance, uptake and defense mechanism in several of these species, notably Brassica juncea and B. napus, against the stress induced by heavy metals. Numerous studies have also been published about the capacity of these species to be used for phytoremediation purposes but with mixed results. This review will focus on the latest developments in the study of the uptake capacity, oxidative damage and biochemical and physiological tolerance and defense mechanisms to heavy metal toxicity on six economically important species: B. juncea, B. napus, B. oleracea, B. carinata, B. rapa and B. nigra. PMID:26247945

  7. Treatment of heavy metal contaminated soils by in situ vitrification

    International Nuclear Information System (INIS)

    Hansen, J.E.

    1991-01-01

    Contaminated soil site remediation objectives call for the destruction, removal, and/or immobilization of contaminant species. Destruction is applicable to hazardous compounds (e.g., hazardous organics such as PCBs; hazardous inorganics such as cyanide); however, it is not applicable to hazardous elements such as the heavy metals. Removal and/or immobilization are typical objectives for heavy metal contaminants present in soil. Many technologies have been developed specifically to meet these needs. One such technology is In Situ Vitrification (ISV), an innovative mobile, onsite, in situ solids remediation technology that has been available on a commercial basis for about two years. ISV holds potential for the safe and permanent treatment/remediation of previously disposed or current process solids waste (e.g., soil, sludge, sediment, tailings) contaminated with hazardous chemical and/or radioactive materials. This paper focuses on the application of ISV to heavy metal-contaminated soils

  8. Preparation of Dithizone Functionalized Polystyrene for Detecting Heavy Metal Ion

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyeon Ho; Kim, Younghun [Kwangwoon University, Seoul (Korea, Republic of)

    2015-04-15

    Colorimetric sensors were usually used to detect specific metal ions using selective color change of solutions. While almost organic dye in colorimetric sensors detected single molecule, dithizone (DTZ) solution could be separately detected above 5 kinds of heavy metal ions by the change of clear color. Namely, DTZ could be used as multicolorimetric sensors. However, DTZ was generally used as aqueous type and paper/pellet-type DTZ was not reported yet. Therefore, in this work, polystyrene (PS) was prepared to composite with DTZ and then DTZ/PS pellet was obtained, which was used to selectively detect 10 kinds of heavy metal ions. When 10 ppm of Hg and Co ions was exposed in DTZ/PS pellets, clear color change was revealed. It is noted that DTZ/PS pellet could be used in detecting of heavy metal ion as dry type.

  9. Interactions between plant hormones and heavy metals responses.

    Science.gov (United States)

    Bücker-Neto, Lauro; Paiva, Ana Luiza Sobral; Machado, Ronei Dorneles; Arenhart, Rafael Augusto; Margis-Pinheiro, Marcia

    2017-01-01

    Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity.

  10. Interactions between plant hormones and heavy metals responses

    Directory of Open Access Journals (Sweden)

    Lauro Bücker-Neto

    2017-04-01

    Full Text Available Abstract Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity.

  11. Predatory insects as bioindicators of heavy metal pollution

    International Nuclear Information System (INIS)

    Nummelin, Matti; Lodenius, Martin; Tulisalo, Esa; Hirvonen, Heikki; Alanko, Timo

    2007-01-01

    Heavy metal concentrations of different predatory insects were studied near by a steel factory and from control sites. Waterstriders (Gerridae), dragon fly larvae (Odonata), antlion larvae (Myrmeleontidae) and ants (Formicidae) were analyzed by AAS. In most cases the metal concentrations were higher near the factory, but e.g. waterstriders had higher cadmium concentrations in control area. Discriminant analysis clearly reveals that all these insect groups can be used as heavy metal indicators. However, the commonly used ants were the least effective in indicating the differences between the factory and control sites. Waterstriders are good in detecting differences in iron and manganese, but seem to be poor in accumulating nickel and lead. Antlions are efficient in detecting differences in iron. Antlions and ants are effective in accumulating manganese; as well antlions are efficient in accumulating cadmium. Waterstriders are poor in accumulating lead, but antlions and ants are effective. - Waterstriders, dragon fly larvae, antlion larvae, and ants can be used as heavy metal indicators

  12. Fluorescent and Colorimetric Electrospun Nanofibers for Heavy-Metal Sensing

    Directory of Open Access Journals (Sweden)

    Idelma A. A. Terra

    2017-12-01

    Full Text Available The accumulation of heavy metals in the human body and/or in the environment can be highly deleterious for mankind, and currently, considerable efforts have been made to develop reliable and sensitive techniques for their detection. Among the detection methods, chemical sensors appear as a promising technology, with emphasis on systems employing optically active nanofibers. Such nanofibers can be obtained by the electrospinning technique, and further functionalized with optically active chromophores such as dyes, conjugated polymers, carbon-based nanomaterials and nanoparticles, in order to produce fluorescent and colorimetric nanofibers. In this review we survey recent investigations reporting the use of optically active electrospun nanofibers in sensors aiming at the specific detection of heavy metals using colorimetry and fluorescence methods. The examples given in this review article provide sufficient evidence of the potential of optically electrospun nanofibers as a valid approach to fabricate highly selective and sensitive optical sensors for fast and low-cost detection of heavy metals.

  13. Heavy metal absorption by vegetables grown in different soils

    International Nuclear Information System (INIS)

    Canova, F.; Riolfatti, M.; Ravazzolo, E.; Da Ros, D.; Brigato, L.

    1995-01-01

    The authors study the bibliographic and experimental data on absorption by vegetables of several heavy metals present in the soil or brought to it via fertilizations, especially with the use of compost coming from waste treatment plants. The presence of heavy metals in the soil causes increased levels of these toxic substances in the edible parts of the vegetables grown in that soil. Not to be neglected is also the absorption by the leaf apparatus of airborne particulate containing heavy metals which deposit on the parts of the vegetable exposed to the air. The available data lack homogeneity of investigation as they have been draw from studies which followed different methodologies. Therefore further studies are required in order to: eliminate some of the variables that might affect the absorption of metals from the soil and supply comparable data. Moreover, a greater number of vegetable species and their different edible parts will have to be taken into consideration

  14. Accumulation of heavy metals in a tropical soil type Oxisol

    International Nuclear Information System (INIS)

    Reynaldo, I.M.; Escudey, M.; Utria, E.; Garcia, D.; Cartaya, O.; Morua, A.

    2003-01-01

    In this investigation sewage sludges from Quibu plant, located in City of the Havana, with the objective of evaluating the capacity of accumulation of heavy metals in a tropical soil type Oxisol when in the wheat plants are cultivated (Triticum aestivum L.) , as well as the potential damages in this plants. Rates of 0, 60, 180 and 300 sludges tons/ soil hectare was applied and the plants were growth in recipient of 5 L of capacity. The levels of heavy metals were evaluated before the and after the crop. The extraction one carries out with the mixture HCl:HNO3 and they were determined by spectroscopy inductively coupled to plasma. Presence of Zn, Cu and Pb were detected in sludges and a tendency decrease is observed to heavy metals retention is observed in soil with the increase of the disposition rate together to a differential behavior of the different chemical species

  15. Heavy metal concentrations in forest litter - indicators of pollutant depositions

    International Nuclear Information System (INIS)

    Angehrn-Bettinazzi, C.; Hertz, J.

    1990-01-01

    By means of a comparison of the heavy metal concentrations in organic litter from different sites it was examined to what extent the heavy metal concentrations correlate with the atmospheric pollution situation. It follows from the variance analyses: The atmospheric pollution situation is the dominating factor for the heavy metal concentration in L litter. The elements Cd and Zn show a pH-sensitivity at the same time. The lead concentration in the L n and L v horizons reflects the atmospheric pollution situation of the corresponding site. Specific pollution patterns, e.g. in the case of hillside sites, are neither detected through the gravitational deposition (open land) nor through the airborne dust concentration; these can be recognized by the monitor 'litter'. Only horizons in the intercrown area with identical tree vegetation, which are characterized in detail, must be used for monitoring. (orig.) [de

  16. Pressure vessel code construction capabilities for a nickel-chromium-tungsten-molybdenum alloy

    International Nuclear Information System (INIS)

    Rothman, M.F.

    1990-01-01

    HAYNES alloy 230 (UNS NO6230) has achieved wide usage in a variety of high-temperature aerospace, chemical process industry and industrial heating applications since its introduction in 1981. Combining high elevated temperature strength with excellent metallurgical stability, environment-resistance and relatively straight forward fabrication characteristics, this Ni-Cr-W-Mo alloy was an excellent candidate for ASME Pressure vessel Code applications. Coverage under case No. 2063 was granted in July, 1989, for both Section I and Section VIII Division 1 construction. In this paper, the metallurgy of 230 alloy will be described, and its design strength capabilities contrasted with those for more established code materials. Other important performance capabilities, such as long-term thermal stability, oxidation-resistance, fatigue-resistance, and resistance to other forms of environmental degradation will be discussed. It will be shown that the combined properties of 230 alloy offer some significant advantages over other materials for applications such as expansion bellows, heat-exchangers, valves and other components in the fossil energy, nuclear energy and chemical process industries, among others

  17. Effect of heavy metals on growth and heavy metal content of Allium porrum L. and Pisum sativum L

    Energy Technology Data Exchange (ETDEWEB)

    Gruenhage, L.; Jaeger, H.J.

    1985-01-01

    The effects of cadmium, lead, zinc and copper, singly and in combination, on yield, heavy metal content and the mineral composition of Allium porrum L. and Pisum sativum L. have been investigated. The Cd, Pb, Zn and Cu concentrations of shoots and roots of Allium porrum increased with increasing heavy metal contamination of soil. However, no visible symptoms of heavy metal toxicity were recognized. The dry matter production was reduced as a function of heavy metal concentration and combination. The mechanisms of combinations were mostly synergistic. The correlation between pollutant contents (nmol/shoot) and yield was higher than the correlation between heavy metal concentrations of soil or shoots (ppm) and yield. Results of regression analyses showed that the inhibition of copper translocation caused by Cd, Pb and Zn was responsible for the yield depressions. The antagonism between Cd and N-deficiency showed that the level of N-supply was without negative effects on yield depressions of Pisum sativum caused by Cd. In contrast to this, the N-form played an important role in Cd-toxicity as the synergism between Cd and NH4 illustrated. K-deficiency as well as acidic nutrient solution (pH=4) diminished the root/shoot-barrier for Cd and therefore Cd-translocation from roots to shoots increased. Concerning calcium, magnesium and iron the decrease of ion uptake caused by Cd was statistically significant higher than yield depression.

  18. Characterization of a heavy metal translocating P-type ATPase gene from an environmental heavy metal resistance Enterobacter sp. isolate.

    Science.gov (United States)

    Chien, Chih-Ching; Huang, Chia-Hsuan; Lin, Yi-Wei

    2013-03-01

    Heavy metals are common contaminants found in polluted areas. We have identified a heavy metal translocating P-type ATPase gene (hmtp) via fosmid library and in vitro transposon mutagenesis from an Enterobacter sp. isolate. This gene is believed to participate in the bacterium's heavy metal resistance traits. The complete gene was identified, cloned, and expressed in a suitable Escherichia coli host cell. E. coli W3110, RW3110 (zntA::Km), GG48 (ΔzitB::Cm zntA::Km), and GG51 (ΔzitB::Cm) were used to study the possible effects of this gene for heavy metal (cadmium and zinc in particular) resistance. Among the E. coli strains tested, RW3110 and GG48 showed more sensitivity to cadmium and zinc compared to the wild-type E. coli W3110 and strain GG51. Therefore, strains RW3110 and GG48 were chosen for the reference hosts for further evaluation of the gene's effect. The results showed that expression of this heavy metal translocating P-type ATPase gene could increase the ability for zinc and cadmium resistance in the tested microorganisms.

  19. Heavy metal pollution in coastal areas of South China: a review.

    Science.gov (United States)

    Wang, Shuai-Long; Xu, Xiang-Rong; Sun, Yu-Xin; Liu, Jin-Ling; Li, Hua-Bin

    2013-11-15

    Coastal areas of South China face great challenges due to heavy metal contamination caused by rapid urbanization and industrialization. In this paper, more than 90 articles on levels, distributions, and sources of heavy metals in sediments and organisms were collected to review the status of heavy metal pollution along coastal regions of South China. The results show that heavy metal levels were closely associated with local economic development. Hong Kong and the Pearl River Estuary were severely contaminated by heavy metals. However, concentrations of heavy metals in sediments from Hong Kong have continually decreased since the early 1990 s. High levels of heavy metals were found in biota from Lingdingyang in Guangdong province. Mollusks had higher concentrations of heavy metals than other species. Human health risk assessments suggested that levels of heavy metals in some seafood from coastal areas of South China exceeded the safety limit. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Novel forward osmosis process to effectively remove heavy metal ions

    KAUST Repository

    Cui, Yue; Ge, Qingchun; Liu, Xiangyang; Chung, Neal Tai-Shung

    2014-01-01

    In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

  1. Novel forward osmosis process to effectively remove heavy metal ions

    KAUST Repository

    Cui, Yue

    2014-10-01

    In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

  2. Using microbiological leaching method to remove heavy metals from sludge

    Directory of Open Access Journals (Sweden)

    Zhuyu Gu

    2017-01-01

    Full Text Available Microbial leaching is one of the most effective methods to remove heavy metals from sludge. In the conducted researches, the sludge samples were processed with Thiobacillus ferrooxidans and Thiobacillus thiooxidans obtained via cultivation, extraction and purification processes. Heavy metals such as Pb, Cd, Cu and Ni were leached from sludge by Thiobacillus ferrooxidans and Thiobacillus thiooxidans within different substrate concentration and pH value conditions. It is defined that from the point of view of economy and efficiency the optimal concentration of FeSO4.7H2O and sulfur for bio-leaching process was 0.2 g. The leaching rates of heavy metals such as Pb, Cd, Cu and Ni of the same concentration were 74.72%, 81.54%, 70.46% and 77.35% respectively. However, no significant differences depending on the pH value among the leaching rates were defined, even for the pH value of 1.5. Along with the removal of heavy metals from sludge, the organic matter, N, P, K were also leached to some extent. The losing rate of phosphorus was the highest and reached 38.44%. However, the content of organic matter, N, P, K in the processed sludge were higher in comparison with level I of the National Soil Quality Standards of China. Ecological risk of heavy metals in sludge before and after leaching was assessed by Index of Geo-accumulation (Igeo and comprehensive potential risk (RI. The results of research defined that the content of heavy metals in sludge meets the level of low ecological risk after leaching and their contents is lower in comparison with the National Agricultural Sludge Standard of China. Sludge leached by biological methods is possible to use for treatment for increasing soil fertility.

  3. IMPACT OF BIOSLUDGE APPLICATION ON HEAVY METALS CONTENT IN SUNFLOWER

    Directory of Open Access Journals (Sweden)

    Marek Slávik

    2012-02-01

    Full Text Available The application of decomposed substrate after continual biogas production is one of the possible ways how to use alternative energy sources with following monitoring of its complex influence on the hygienic state of soil with the emphasis on heavy metal input. The substances from bilge and drain sediments from water panels, also biosludge gained by continual co-fermentation of animal excrements belong to these compounds. The biosludge application is connected with possible risk of cadmium and lead, also other risky elements input into the soil. The analyses of applicated sludge prove that the determined heavy metals contents are compared with limitary value. These facts - hygienic state of soil, pH influence this limitary value and biosludge is suitable for soil application. The total heavy metals content in soil is related to the increased cadmium, nickel, chromium and cobalt contents. The analyses of heavy metals contents in sunflower seeds show that the grown yield does not comply with the legislative norms from the stand point of heavy metals content due to high zinc and nickel contents. Copper, cadmium, lead, chromium contents fulfil limitary values, for cobalt content the value is not mentioned in Codex Alimentarius. The nickel value in the control variant seeds is 2.2 times higher than the highest acceptable amount, then in variant where the sludge was applicated the nickel content was increased by 1.6 times. In the case of zinc there was increasing content in individual variants 4.7, or 4.8 times. The direct connection with the higher accumulation of zinc and nickel in soil by the influence of biosludge application is not definitely surveyed, the increased heavy metals contents in sunflower were primarily caused by their increased contents in soils.

  4. Heavy metals accumulation affects bone microarchitecture in osteoporotic patients.

    Science.gov (United States)

    Scimeca, Manuel; Feola, Maurizio; Romano, Lorenzo; Rao, Cecilia; Gasbarra, Elena; Bonanno, Elena; Brandi, Maria Luisa; Tarantino, Umberto

    2017-04-01

    Bone metabolism is affected by mechanical, genetic, and environmental factors and plays a major role in osteoporosis. Nevertheless, the influence of environmental pollution on the occurrence of osteoporosis is still unclear and controversial. In this context, heavy metals are the most important pollutants capable to affect bone mass. The aim of this study was to investigate whether heavy metals accumulation in bone tissues could be related to the altered bone metabolism and architecture of osteoporotic patients. To this end, we analyzed 25 bone head biopsies osteoporotic patients and 25 bone head biopsies of osteoarthritic patients. Moreover we enrolled 15 patients underwent hip arthroplasty for high-energy hip fracture or osteonecrosis of the femoral head as a control group. Bone head biopsies were studied by BioQuant-osteo software, scanning electron microscopy and Energy Dispersive X-ray microanalysis. We found a prevalence of lead, cadmium and chromium accumulation in osteoporotic patients. Noteworthy, high levels of sclerostin, detected by immunohistochemistry, correlate with the accumulation of heavy metal found in the bone of osteoporotic patients, suggesting a molecular link between heavy metal accumulation and bone metabolism impairment. In conclusion, the presence of heavy metals into bone shed new light on the comprehension of the pathogenesis of osteoporosis since these elements could play a non redundant role in the development of osteoporosis at cellular/molecular and epigenetic level. Nevertheless, in vivo and in vitro studies need to better elucidate the molecular mechanism in which heavy metals can participate to osteoporosis. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1333-1342, 2017. © 2016 Wiley Periodicals, Inc.

  5. Analysis of heavy metals in road-deposited sediments.

    Science.gov (United States)

    Herngren, Lars; Goonetilleke, Ashantha; Ayoko, Godwin A

    2006-07-07

    Road-deposited sediments were analysed for heavy metal concentrations at three different landuses (residential, industrial, commercial) in Queensland State, Australia. The sediments were collected using a domestic vacuum cleaner which was proven to be highly efficient in collecting sub-micron particles. Five particle sizes were analysed separately for eight heavy metal elements (Zn, Fe, Pb, Cd, Cu, Cr, Al and Mn). At all sites, the maximum concentration of the heavy metals occurred in the 0.45-75 microm particle size range, which conventional street cleaning services do not remove efficiently. Multicriteria decision making methods (MCDM), PROMETHEE and GAIA, were employed in the data analysis. PROMETHEE, a non-parametric ranking analysis procedure, was used to rank the metal contents of the sediments sampled at each site. The most polluted site and particle size range were the industrial site and the 0.45-75 microm range, respectively. Although the industrial site displayed the highest metal concentrations, the highest heavy metal loading coincided with the highest sediment load, which occurred at the commercial site. GAIA, a special form of principal component analysis, was applied to determine correlations between the heavy metals and particle size ranges and also to assess possible correlation with total organic carbon (TOC). The GAIA-planes revealed that irrespective of the site, most of the heavy metals are adsorbed to sediments below 150 microm. A weak correlation was found between Zn, Mn and TOC at the commercial site. This could lead to higher bioavailability of these metals through complexation reactions with the organic species in the sediments.

  6. Heavy metal pollution in coastal areas of South China: A review

    International Nuclear Information System (INIS)

    Wang, Shuai-Long; Xu, Xiang-Rong; Sun, Yu-Xin; Liu, Jin-Ling; Li, Hua-Bin

    2013-01-01

    Highlights: • Heavy metal contamination in coastal areas of South China has been reviewed. • Heavy metal levels were closely related to economic development in past decades. • Heavy metal levels from Hong Kong continually decreased from the early 1990s. • Higher concentrations of heavy metals were found in mollusk. • Levels of heavy metals in part of seafood exceeded the safety limit. -- Abstract: Coastal areas of South China face great challenges due to heavy metal contamination caused by rapid urbanization and industrialization. In this paper, more than 90 articles on levels, distributions, and sources of heavy metals in sediments and organisms were collected to review the status of heavy metal pollution along coastal regions of South China. The results show that heavy metal levels were closely associated with local economic development. Hong Kong and the Pearl River Estuary were severely contaminated by heavy metals. However, concentrations of heavy metals in sediments from Hong Kong have continually decreased since the early 1990s. High levels of heavy metals were found in biota from Lingdingyang in Guangdong province. Mollusks had higher concentrations of heavy metals than other species. Human health risk assessments suggested that levels of heavy metals in some seafood from coastal areas of South China exceeded the safety limit

  7. Heavy metals and terrestrial cryptograms. A bibliographic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Margot, J.; Romain, M.T.

    1976-01-01

    Heavy metals pollution is a present-day problem as it concerns the entire continent. Terrestrial cryptograms are not of long-standing use as bioindicators in this respect and require a synthesis of the recent publications. Characteristics of heavy metals in the atmosphere, especially mosses and lichens, utilizable as bioindicators are briefly reported. They are followed by more accurate descriptions of phenomena on the level with the plant itself: absorption, accumulation, translocation, tolerance and other physico-chemical processes. The statement of deleterious effects on these organisms is then given: external symptoms, cytological localization, metabolic disturbances and ecological aspects. Further research propositions are presented. 128 references.

  8. [Hyperspectral remote sensing in monitoring the vegetation heavy metal pollution].

    Science.gov (United States)

    Li, Na; Lü, Jian-sheng; Altemann, W

    2010-09-01

    Mine exploitation aggravates the environment pollution. The large amount of heavy metal element in the drainage of slag from the mine pollutes the soil seriously, doing harm to the vegetation growing and human health. The investigation of mining environment pollution is urgent, in which remote sensing, as a new technique, helps a lot. In the present paper, copper mine in Dexing was selected as the study area and China sumac as the study plant. Samples and spectral data in field were gathered and analyzed in lab. The regression model from spectral characteristics for heavy metal content was built, and the feasibility of hyperspectral remote sensing in environment pollution monitoring was testified.

  9. Nutrients and heavy metal distribution in thermally treated pig manure

    DEFF Research Database (Denmark)

    Kuligowski, Ksawery; Poulsen, Tjalfe G.; Stoholm, Peder

    2008-01-01

    Ash from pig manure treated by combustion and thermal gasification was characterized and compared in terms of nutrient, i.e., potassium (K), phosphorus (P) and heavy metal, i.e., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) contents. Total nutrient and metal concentrations...... that ash from gasified manure contained more water-extractable K in comparison with combusted manure whereas the opposite was the case with respect to P. Heavy metals Ni, Cr and Cd were present in higher concentrations in the fine particle size fractions (

  10. Mosses accumulate heavy metals from the substrata of coal ash

    Directory of Open Access Journals (Sweden)

    Vukojević Vanja

    2005-01-01

    Full Text Available Plants that are able to accumulate and tolerate extraordinarily high concentrations of heavy metals (hyperaccumulators can be used for phytoremediation (removal of contaminants from soils or phytomining (growing a crop of plants to harvest the metals. Two moss species, Bryum capillare Hedw. and Ceratodon purpureus Hedw., were tested as potential phytoremedies under in vivo conditions on a coal ash disposal site in the surroundings of Obrenovac (NW Serbia. The content of various heavy metals (iron, manganese zinc, lead, nickel, cadmium, and copper in the mosses and substrata were investigated over a period of three years. Iron and zinc were found to have the highest concentration in the mosses.

  11. [Heavy metal poisoning and renal injury in children].

    Science.gov (United States)

    Rong, Li-Ping; Xu, Yuan-Yuan; Jiang, Xiao-Yun

    2014-04-01

    Along with global environmental pollution resulting from economic development, heavy metal poisoning in children has become an increasingly serious health problem in the world. It can lead to renal injury, which tends to be misdiagnosed due to the lack of obvious or specific early clinical manifestations in children. Early prevention, diagnosis and intervention are valuable for the recovery of renal function and children's good health and growth. This paper reviews the mechanism of renal injury caused by heavy metal poisoning in children, as well as the clinical manifestations, diagnosis, and prevention and treatment of renal injury caused by lead, mercury, cadmium, and chromium.

  12. Electrodialytic removal of heavy metals from fly ashes

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul

    2002-01-01

    The aim of the Ph.D. work was to develop the electrodialytic remediation method for removal of heavy metals from fly ashes. The work was focused on two types of fly ashes: fly ashes from wood combustion and fly ashes from municipal solid waste incineration.......The aim of the Ph.D. work was to develop the electrodialytic remediation method for removal of heavy metals from fly ashes. The work was focused on two types of fly ashes: fly ashes from wood combustion and fly ashes from municipal solid waste incineration....

  13. Assessing fly ash treatment: Remediation and stabilization of heavy metals

    DEFF Research Database (Denmark)

    Lima, A.T.; Ottosen, Lisbeth M.; Ribeiro, Alexandra B.

    2012-01-01

    Fly ashes from Municipal Solid Waste (MSW), straw (ST) and co-combustion of wood (CW) are here analyzed with the intent of reusing them. Two techniques are assessed, a remediation technique and a solidification/stabilization one. The removal of heavy metals from fly ashes through the electrodialy......Fly ashes from Municipal Solid Waste (MSW), straw (ST) and co-combustion of wood (CW) are here analyzed with the intent of reusing them. Two techniques are assessed, a remediation technique and a solidification/stabilization one. The removal of heavy metals from fly ashes through...

  14. Monte Carlo criticality analysis of simple geometries containing tungsten-rhenium alloys engrained with uranium dioxide and uranium mononitride

    International Nuclear Information System (INIS)

    Webb, Jonathan A.; Charit, Indrajit

    2011-01-01

    Highlights: → The addition of rhenium to the tungsten matrix within W-UO 2 and W-UN CERMET materials can help reduce the risk of submersion criticality accidents while increasing the strength and ductility of tungsten based nuclear fuel elements. → The addition of rhenium up to 30 at.% to simple geometries containing W-UO 2 mixtures can increase the critical mass by 65 kg. → The addition of rhenium up to 30 at.% to simple geometries containing W-UN mixtures can increase the critical mass by 22 kg. → The addition of rhenium by up to 30 at.% to simple geometries containing W-UO 2 mixtures can reduce the change in reactivity change due to water submersion by $5.07. → The addition of rhenium by up to 30 at.% to simple geometries containing W-UN mixtures can reduce the change in reactivity due to water submersion by $3.24. - Abstract: The critical mass and dimensions of simple geometries containing highly enriched uranium dioxide (UO 2 ) and uranium mononitride (UN) encapsulated in tungsten-rhenium alloys are determined using MCNP5 criticality calculations. Spheres as well as cylinders with length to radius ratios of 1.82 are computationally built to consist of 60 vol.% fuel and 40 vol.% metal matrix. Within the geometries, the uranium is enriched to 93 wt.% uranium-235 and the rhenium content within the metal alloy was modeled over the range of 0-30 at.%. The spheres containing UO 2 were determined to have a critical radius of 18.29-19.11 cm and a critical mass ranging from 366 kg to 424 kg. The cylinders containing UO 2 were found to have a critical radius ranging from 17.07 cm to 17.84 cm with a corresponding critical mass of 406-471 kg. Spheres engrained with UN were determined to have a critical radius ranging from 14.82 cm to 15.19 cm and a critical mass between 222 kg and 242 kg. Cylinders which were engrained with UN were determined to have a critical radius ranging from 13.81 cm to 14.15 cm and a corresponding critical mass of 245-267 kg. The critical

  15. Microstructure formation in partially melted zone during gas tungsten arc welding of AZ91 Mg cast alloy

    International Nuclear Information System (INIS)

    Zhu Tianping; Chen, Zhan W.; Gao Wei

    2008-01-01

    During gas tungsten arc (GTA) welding of AZ91 Mg cast alloy, constitutional liquid forms locally in the original interdendritic regions in the partially melted zone (PMZ). The PMZ re-solidification behaviour has not been well understood. In this study, the gradual change of the re-solidification microstructure within PMZ from base metal side to weld metal side was characterised. High cooling rate experiments using Gleeble thermal simulator were also conducted to understand the morphological change of the α-Mg/β-Mg 17 Al 12 phase interface formed during re-solidification after partial melting. It was found that the original partially divorced eutectic structure has become a more regular eutectic phase in most of the PMZ, although close to the fusion boundary the re-solidified eutectic is again a divorced one. Proceeding the eutectic re-solidification, if the degree of partial melting is sufficiently high, α-Mg re-solidified with a cellular growth, resulting in a serrated interface between α-Mg and α-Mg/β-Mg 17 Al 12 in the weld sample and between α-Mg and β-Mg 17 Al 12 (fully divorced eutectic) in Gleeble samples. The morphological changes affected by the peak temperature and cooling rate are also explained

  16. Experimental investigation of the behaviour of tungsten and molybdenum alloys at high strain-rate and temperature

    CERN Document Server

    Scapin, Martina; Carra, Federico; Peroni, Lorenzo

    2015-01-01

    The introduction in recent years of new, extremely energetic particle accelerators such as the Large Hadron Collider (LHC) gives impulse to the development and testing of refractory metals and alloys based on molybdenum and tungsten to be used as structural materials. In this perspective, in this work the experimental results of a tests campaign on Inermet® IT180 and pure Molybdenum (sintered by two different producers) are presented. The investigation of the mechanical behaviour was performed in tension varying the strain-rates, the temperatures and both of them. Overall six orders of magnitude in strain-rate (between 10−3 and 103 s−1) were covered, starting from quasi-static up to high dynamic loading conditions. The high strain-rate tests were performed using a direct Hopkinson Bar setup. Both in quasi-static and high strain-rate conditions, the heating of the specimens was obtained with an induction coil system, controlled in feedback loop, based on measurements from thermocouples directly welded on...

  17. Application of stress relaxation testing in evaluation of creep strength of a tungsten-alloyed 10% Cr cast steel

    International Nuclear Information System (INIS)

    Raghavender Rao, G.; Gupta, O.P.; Pradhan, B.

    2011-01-01

    Uniaxial isothermal stress relaxation tests (SRT) were performed on a tungsten-alloyed 10% Cr cast steel (G-X12Cr Mo W V Nb N 10 1 1) at temperatures of 580, 600 and 620 o C and initial strain levels of 0.2, 0.5 and 0.8%. Inelastic strain rates for different stresses were estimated from the stress versus time data generated from the tests. Conventional creep tests were also conducted on the same material at 580, 600 and 620 o C and at different stress levels. The strain rate data estimated from SRT were compared with minimum creep rates derived from the creep tests; the strain rates estimated from SRT with 0.8% initial strain level are in better agreement than those estimated from SRT with 0.2 and 0.5% initial strain levels. In order to ascertain the technique, stress relaxation behaviour was estimated from creep test data and compared with the stress relaxation curves obtained from SRT at corresponding temperatures. The stress relaxation curves obtained from SRT with 0.8% initial strain level are in good agreement with the stress relaxation curves estimated from the creep tests. It is concluded that the stress relaxation test with initial strain level of 0.8% could be considered as an appropriate short-term test technique for estimation of creep strength of newly developed materials.

  18. The effect of axial external magnetic field on tungsten inert gas welding of magnesium alloy

    Science.gov (United States)

    Li, Caixia; Zhang, Xiaofeng; Wang, Jing

    2018-04-01

    The influences of axial external magnetic field on the microstructure and mechanical property of the AZ31 magnesium (Mg) alloy joints were studied. The microstructure of Mg alloy joint consisted of the weld seam, heat affected zone and base metal zone. The average grain size of weld seam welded with magnetic field is 39 μm, which is 38% smaller than that of the joint welded with absence of magnetic field. And the microhardness of weld seam increases with the help of magnetic field treatment, owing to the coarse grain refinement. With coil current of 2.0A, the maximum mechanical property of joint increases 6.7% to 255 MPa over the specimen without magnetic field treatment. Furthermore, fracture location is near heat affected area and the fracture surface is characterized with ductile fracture.

  19. Migration of heavy metals in soils in a uranium mining area

    International Nuclear Information System (INIS)

    Hu Ruixia; Gao Bai; Hu Baoqun; Feng Jiguang

    2009-01-01

    Contents of several heavy metals (Zn,Ni,Cu,Cd,Pb) in soil samples collected from different depths of the soil sections in a uranium mining area were analyzed, and vertical migration dis-ciplines of heavy metals were obtained. The results show that the concents of heavy metals in vertical direction decrease as the soil increases in thickness and there is a trend of facies-cumulation for the heavy metals. The accumulation status of each heavy metal in soils differs, which is dependent on the content and migration velocity of the heavy metal itself, the local natural environment about the soil, etc. (authors)

  20. Controllable synthesis of molybdenum tungsten disulfide alloy for vertically composition-controlled multilayer

    Science.gov (United States)

    Song, Jeong-Gyu; Ryu, Gyeong Hee; Lee, Su Jeong; Sim, Sangwan; Lee, Chang Wan; Choi, Taejin; Jung, Hanearl; Kim, Youngjun; Lee, Zonghoon; Myoung, Jae-Min; Dussarrat, Christian; Lansalot-Matras, Clement; Park, Jusang; Choi, Hyunyong; Kim, Hyungjun

    2015-01-01

    The effective synthesis of two-dimensional transition metal dichalcogenides alloy is essential for successful application in electronic and optical devices based on a tunable band gap. Here we show a synthesis process for Mo1−xWxS2 alloy using sulfurization of super-cycle atomic layer deposition Mo1−xWxOy. Various spectroscopic and microscopic results indicate that the synthesized Mo1−xWxS2 alloys have complete mixing of Mo and W atoms and tunable band gap by systematically controlled composition and layer number. Based on this, we synthesize a vertically composition-controlled (VCC) Mo1−xWxS2 multilayer using five continuous super-cycles with different cycle ratios for each super-cycle. Angle-resolved X-ray photoemission spectroscopy, Raman and ultraviolet–visible spectrophotometer results reveal that a VCC Mo1−xWxS2 multilayer has different vertical composition and broadband light absorption with strong interlayer coupling within a VCC Mo1−xWxS2 multilayer. Further, we demonstrate that a VCC Mo1−xWxS2 multilayer photodetector generates three to four times greater photocurrent than MoS2- and WS2-based devices, owing to the broadband light absorption. PMID:26204328

  1. Factors Affecting the Binding of a Recombinant Heavy Metal-Binding Domain (CXXC motif Protein to Heavy Metals

    Directory of Open Access Journals (Sweden)

    Kamala Boonyodying

    2012-06-01

    Full Text Available A number of heavy metal-binding proteins have been used to study bioremediation. CXXC motif, a metal binding domain containing Cys-X-X-Cys motif, has been identified in various organisms. These proteins are capable of binding various types of heavy metals. In this study, heavy metal binding domain (CXXC motif recombinant protein encoded from mcsA gene of S. aureus were cloned and overexpressed in Escherichia coli. The factors involved in the metal-binding activity were determined in order to analyze the potential of recombinant protein for bioremediation. A recombinant protein can be bound to Cd2+, Co2+, Cu2+ and Zn2+. The thermal stability of a recombinant protein was tested, and the results showed that the metal binding activity to Cu2+ and Zn2+ still exist after treating the protein at 85ºC for 30 min. The temperature and pH that affected the metal binding activity was tested and the results showed that recombinant protein was still bound to Cu2+ at 65ºC, whereas a pH of 3-7 did not affect the metal binding E. coli harboring a pRset with a heavy metal-binding domain CXXC motif increased the resistance of heavy metals against CuCl2 and CdCl2. This study shows that metal binding domain (CXXC motif recombinant protein can be effectively bound to various types of heavy metals and may be used as a potential tool for studying bioremediation.

  2. On the structure of heavy metals

    International Nuclear Information System (INIS)

    Friedel, J.

    1958-01-01

    The properties of the last series of Mendeleef's table are compared with those of the elements of the preceding series. This comparison suggests an electronic structure of the 'transition metal' type, with narrow bands, at the beginning of this series (up to certain phases at least of plutonium); then of the rare earth metal type, with independent non-saturated internal layers, further on in the series. The 5 f orbits seem to play an important part in these two types of structure, from uranium on. A more detailed study of the very heavy elements (americium and beyond) and alloys would allow these conclusions to be confirmed. Certain general points, concerning the nature of homopolar connections and paramagnetism in the transition metals, are developed in an additional section. (author) [fr

  3. REMOVAL OF HEAVY-METALS FROM WASTEWATER USING A ...

    African Journals Online (AJOL)

    Enos W. Wambu1*, Stephen Attahiru2, Paul M. Shiundu3 and John Wabomba2. 1Department ..... Activated carbons from seed hull of palm tree. 4. 333 .... Akcay, H.; Oguz, A.; Karapire, C. Study of heavy metal pollution and speciation in Buyak.

  4. Chemical Speciation and Mobility of Some Heavy Metals in Soils ...

    African Journals Online (AJOL)

    The mobility of some heavy metals (Fe, Co, Ni and Mn) in soils around automobile waste dumpsites in Northern part of Niger Delta was assessed using Tessier et al. five syteps sequential chemical extraction procedure. The results showed that majority of iron and manganese were associated with the residual fraction with ...

  5. Heavy metal content in compost and earthworms from home composters

    Directory of Open Access Journals (Sweden)

    Bożym Marta

    2017-12-01

    Full Text Available The paper presents the results of compost tests from home composters and earthworms living there, that treating waste into compost. The samples were taken from home composters and allotment gardens from Opole Region. The composting material was green waste. The total content of heavy metals (Cd, Pb, Cu, Zn, Ni Cr in compost and compost earthworms’ samples were determined. It was found that the compost samples were not contaminated with heavy metals. According to the Polish classification of composts from municipal wastes, the composts met the requirements for first class of quality. The composts did not exceed the limits of heavy metals specified in the Polish law for solid organic fertilizers. The degree of metal accumulation by compost earthworms depended on the type of metal. The high value of the bioaccumulation factor (BAF was obtained for Cd, Pb and Zn. No accumulation of other metals (Ni, Cr, Cu in earthworm bodies was found. It has been found that earthworm species, naturally occurring in Poland, can also be used as potential bioindicators of metals in the environment, such as the species Eisenia fetida. The aim of the study was to evaluate the heavy metal content in composts from home composters and ability to accumulate metals by compost earthworms.

  6. Variation of heavy metal levels in the tissues of Periophthalmus ...

    African Journals Online (AJOL)

    Variation of heavy metal levels in the tissues of Periophthalmus papillio from the mangrove swamps of the Bukuma oilfield, Rivers State. ... Generally elevated metal levels in both tissues were recorded at the stations with wellheads, implicating oil-related activities as the main source of contamination. However, the levels in ...

  7. Growth response and heavy metals tolerance of Axonopus affinis ...

    African Journals Online (AJOL)

    Jane

    2010-12-20

    Dec 20, 2010 ... 1Laboratorio de Fisiología Vegetal, Escuela Nacional de Ciencias ... 3Dirección de Seguridad y Medio Ambiente, Instituto Mexicano del Petróleo, México City 07730, México. ... Generally, heavy metals are not degraded.

  8. Electrodialytic Remediation of Heavy Metal Polluted Soil. An Innovative Technique

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Hansen, Henrik; Karlsmose, Bodil

    1997-01-01

    Electrodialytic remediationof heavy metal polluted soil is a newly developed method which combines the electrokinetic movement of ions in soil with the principle of electrodialysis. The method has prowen to work in laboratorscale and at presnet two types of pilot plants are build....

  9. Levels of micronutrients and heavy metals in cord blood and ...

    African Journals Online (AJOL)

    The basis of the impact of HAP on maternal and fetal health was assessed by determining the levels of teratogenic heavy metals [Lead (Pb), Mercury (Hg)] and micronutrients associated with DNA methylation [Zinc (Zn), Iodine (I), vitamins B6 and B12, folic acid and homocysteine] in cord blood of babies and maternal blood ...

  10. Fate of heavy metals and agrochemicals in biochar amended soils

    Science.gov (United States)

    Heavy metals and agrochemicals are the key targets for biochar-induced mitigation of runoff/groundwater contamination. Inorganic and organic contaminants interact differently with biochars as well as soil components. Mechanistic understandings are needed on sorption, desorption, and competitive sor...

  11. Sorption of Heavy Metals from Mine Wastewater by Activated ...

    African Journals Online (AJOL)

    A study on sorption of heavy metal ions: Lead (Pb2+), Copper (Cu2+) and Cadmium (Cd2+) from mine wastewater by activated carbons prepared from coconut husk was conducted. The activated carbons were prepared by carbonisation of the husk at 900 ºC pyrolysis temperature, followed by steam activation of the ...

  12. Characterization of Heavy Metals in Vegetables Using Inductive ...

    African Journals Online (AJOL)

    Journal of Applied Sciences and Environmental Management ... Cauliflower and Onion showed high amount of Pb. On the other hand, Cucumber and Cauliflower registered maximum content of Zn. The heavy metal concentration in vegetables was within the prescribed safety limits except Fe owing to iron-rich soil of the ...

  13. Heavy metal speciation and their accumulation in sediments of Lake ...

    African Journals Online (AJOL)

    UFUOMA

    Key words: Heavy metals, chemical speciation, sediments, Burullus, Lake. INTRODUCTION ..... fuel for use in internal combustion engines and in making batteries. ..... (Tuner, 1989). According to this model, human risk assessment was .... 593 - 594. Hökanson L (1980). "Ecological Risk Index for Aquatic Pollution. Control.

  14. Biomonitoring of some heavy metal contaminations from a steel ...

    African Journals Online (AJOL)

    Soil and plants growing in the vicinity of industrial areas display increased concentrations of heavy metals and give an indication of the environmental quality. The contamination source for aluminum, iron, nickel and lead in the Botanical garden of Mobarakeh Steel Company was recognized by analyzing the leaves and ...

  15. Extraction of certain heavy metals from sewage sludge using ...

    African Journals Online (AJOL)

    The removal of heavy metal from sludge before disposal or application to farmland is a necessary step to achieve a more safe sludge usage or disposal. Chemical extraction using inorganic acids (nitric, hydrochloric) and organic acids (citric, oxalic) were tested for extraction of chromium, copper, nickel, lead and zinc from ...

  16. Heavy metals in green vegetables and soils from vegetable gardens ...

    African Journals Online (AJOL)

    Edible portions of five varieties of green vegetables, namely amaranth, chinese cabbage, cowpea leaves, leafy cabbage and pumpkin leaves, collected from several areas in Dar es Salaam, were analyzed for lead, cadmium, chromium, zinc, nickel and copper. Except for zinc, the levels of heavy metals in the vegetables ...

  17. Heavy metals and inorganic constituents in medicinal plants of ...

    African Journals Online (AJOL)

    Heavy metals such as Cr, Fe, Zn, Mn, Ni, Pb, Cu and Cd, and inorganic ions like HCO3-, CO32-, Ca2+, Mg2+, Cl-, Na+, SO42-, NO3-, Fe2+ and F- were investigated in medicinally important plants: Taraxacam officinale, Cichorium intybus and Figonia critica, applying atomic absorption spectrophotometer techniques. In the ...

  18. Heavy metal concentrations in, and human health risk assessment ...

    African Journals Online (AJOL)

    Water, sediment and fish samples were collected for six months and heavy metals were determined using an Atomic Absorption Spectrometer. Fe ranked highest in water and sediment, with concentrations of 2.74 mg l−1 and 61.60 mg kg−1, respectively. Metals followed the magnitude of Fe > Mn > Ni > V > Pb in the water ...

  19. Heavy metals pollution at municipal solid waste dumpsites in Kano ...

    African Journals Online (AJOL)

    Soil samples collected from two major dumpsites each in Kano and Kaduna states were investigated for heavy metals pollution. Each of the dumpsite was divided into north, south, east and west. Four soil samples were collected at a depth of 0-15 cm from each part and pooled to form a composite sample. Soil samples from ...

  20. Assessment of Heavy Metals Pollution in Dumpsites in Ilorin ...

    African Journals Online (AJOL)

    Speciation and distribution of heavy metals in soil controls the degree to which metals and their compounds are mobile, extractable, and plant available. Eight strategically located dumpsites in Ilorin metropolis (an averagely growing city and a state capital) were chosen for dumpsites-soil characteristics study. Both the ...