WorldWideScience

Sample records for mercury sulfides

  1. Bioavailability and stability of mercury sulfide in Armuchee (USA) soil

    International Nuclear Information System (INIS)

    Han, Fengxiang; Shiyab, Safwan; Su, Yi; Monts, David L.; Waggoner, Charles A.; Matta, Frank B.

    2007-01-01

    Because of the adverse effects of elemental mercury and mercury compounds upon human health, the U.S. Department of Energy (DOE) is engaged in an on-going effort to monitor and remediate mercury-contaminated DOE sites. In order to more cost effectively implement those extensive remediation efforts, it is necessary to obtain an improved understanding of the role that mercury and mercury compounds play in the ecosystem. We have conducted pilot scale experiments to study the bioavailability of mercury sulfide in an Armuchee (eastern US ) soil. The effects of plants and incubation time on chemical stability and bioavailability of HgS under simulated conditions of the ecosystem have been examined, as has the dynamics of the dissolution of mercury sulfide by various extractants. The results show that mercury sulfide in contaminated Armuchee soil was still to some extent bioavailable to plants. After planting, soil mercury sulfide is more easily dissolved by both 4 M and 12 M nitric acid than pure mercury sulfide reagent. Dissolution kinetics of soil mercury sulfide and pure chemical reagent by nitric acid are different. Mercury release by EDTA from HgS-contaminated soil increased with time of reaction and soil mercury level. Chelating chemicals increase the solubility and bioavailability of mercury in HgS-contaminated soil. (authors)

  2. Bioavailability and Methylation Potential of Mercury Sulfides in Sediments

    Science.gov (United States)

    2014-08-01

    cells by X-ray microbeam analysis. Science 2004, 306, (5696), 686-687. 172. Suzuki, Y.; Kelly, S. D.; Kemner, K. M.; Banfield, J. F., Radionuclide...submitted to Environmental Modeling. Conference presentations Hsu-Kim H., Zhang T., Kucharzyk K., Ticknor J., Pham A., Deshusses M.A. Nanoscale...mercury-sulfide-organic matter interactions: Implications for mercury bioavailability and methylation potential. International Conference on Mercury and

  3. Formation of mercury sulfide from Hg(II)−thiolate complexes in natural organic matter

    Science.gov (United States)

    Alain Manceau,; Cyprien Lemouchi,; Mironel Enescu,; Anne-Claire Gaillot,; Martine Lanson,; Valerie Magnin,; Pieter Glatzel,; Poulin, Brett; Ryan, Joseph N.; Aiken, George R.; Isabelle Gautier-Lunea,; Kathryn L. Nagy,

    2015-01-01

    Methylmercury is the environmental form of neurotoxic mercury that is biomagnified in the food chain. Methylation rates are reduced when the metal is sequestered in crystalline mercury sulfides or bound to thiol groups in macromolecular natural organic matter. Mercury sulfide minerals are known to nucleate in anoxic zones, by reaction of the thiol-bound mercury with biogenic sulfide, but not in oxic environments. We present experimental evidence that mercury sulfide forms from thiol-bound mercury alone in aqueous dark systems in contact with air. The maximum amount of nanoparticulate mercury sulfide relative to thiol-bound mercury obtained by reacting dissolved mercury and soil organic matter matches that detected in the organic horizon of a contaminated soil situated downstream from Oak Ridge, TN, in the United States. The nearly identical ratios of the two forms of mercury in field and experimental systems suggest a common reaction mechanism for nucleating the mineral. We identified a chemical reaction mechanism that is thermodynamically favorable in which thiol-bound mercury polymerizes to mercury–sulfur clusters. The clusters form by elimination of sulfur from the thiol complexes via breaking of mercury–sulfur bonds as in an alkylation reaction. Addition of sulfide is not required. This nucleation mechanism provides one explanation for how mercury may be immobilized, and eventually sequestered, in oxygenated surface environments.

  4. Use of sulfide-containing liquors for removing mercury from flue gases

    Science.gov (United States)

    Nolan, Paul S.; Downs, William; Bailey, Ralph T.; Vecci, Stanley J.

    2006-05-02

    A method and apparatus for reducing and removing mercury in industrial gases, such as a flue gas, produced by the combustion of fossil fuels, such as coal, adds sulfide ions to the flue gas as it passes through a scrubber. Ideally, the source of these sulfide ions may include at least one of: sulfidic waste water, kraft caustic liquor, kraft carbonate liquor, potassium sulfide, sodium sulfide, and thioacetamide. The sulfide ion source is introduced into the scrubbing liquor as an aqueous sulfide species. The scrubber may be either a wet or dry scrubber for flue gas desulfurization systems.

  5. Red coloration by heat treatment of the coprecipitate of cadmium sulfide and mercury(II) sulfide prepared from the nitrates

    International Nuclear Information System (INIS)

    Nakahara, Fujiya

    1979-01-01

    The effects of starting salts on the color, particle size and crystal structure of mercury-cadmium-sulfide pigments were investigated. The coprecipitate (N-S) of cadmium sulfide and mercury (II) sulfide was prepared by adding sodium sulfide solution to a mixed cadmium-mercury (II) nitrate solution. The coprecipitate (C-S) of cadmium sulfide and mercury (II) sulfide was also prepared from the mixed solution of their chlorides by the same method as described above. The coprecipitated products were heat-treated (calcination or hydrothermal treatment) at 350 0 C for 2 hours and subsequent changes in powder properties of both products were compared from each other. The powder properties of N-S, C-S and their heat-treated products were investigated by spectral reflectance, electron microscopy, X-ray diffraction and specific surface area measurements. Sample (N-C) obtained by the calcination of N-S was brown, indicating no red coloration, but the calcined product (C-C) of C-S developed a red color. Cl - and hot water were found to be effective for the red color development of the pigment. The effectiveness was confirmed by calcining N-S in the presence of NaCl or by treating it hydrothermally. It was found that halides other than NaCl, (e.g., NH 4 Cl, KCl, KBr and KI), were also effective for the color development of the pigment. The red samples are solid solutions with a basically hexagonal CdS structure, and it appears that CdS takes up HgS without any apparent structural changes. The particle size of the red samples are larger than those of the non red samples. (author)

  6. Sulfide treatment to inhibit mercury adsorption onto activated carbon in carbon-in-pulp gold recovery circuits

    Energy Technology Data Exchange (ETDEWEB)

    Touro, F.J.; Lipps, D.A.

    1988-03-29

    A process for treating a mercury-contaminated, precious metal-containing ore slurry is described comprising: (a) reacting sulfide anions in an aqueous ore slurry of a mercury and precious metal-containing carbonaceous ore, and (b) conducting a simultaneous cyanide leach and carbon-in-pulp adsorption of the precious metal from the carbonaceous ore in the sulfide-containing ore slurry.

  7. Dissolved organic matter enhances microbial mercury methylation under sulfidic conditions

    Science.gov (United States)

    Graham, Andrew M.; Aiken, George R.; Gilmour, Cynthia

    2012-01-01

    Dissolved organic matter (DOM) is generally thought to lower metal bioavailability in aquatic systems due to the formation of metal–DOM complexes that reduce free metal ion concentrations. However, this model may not be pertinent for metal nanoparticles, which are now understood to be ubiquitous, sometimes dominant, metal species in the environment. The influence of DOM on Hg bioavailability to microorganisms was examined under conditions (0.5–5.0 nM Hg and 2–10 μM sulfide) that favor the formation of β-HgS(s) (metacinnabar) nanoparticles. We used the methylation of stable-isotope enriched 201HgCl2 by Desulfovibrio desulfuricans ND132 in short-term washed cell assays as a sensitive, environmentally significant proxy for Hg uptake. Suwannee River humic acid (SRHA) and Williams Lake hydrophobic acid (WLHPoA) substantially enhanced (2- to 38-fold) the bioavailability of Hg to ND132 over a wide range of Hg/DOM ratios (9.4 pmol/mg DOM to 9.4 nmol/mg DOM), including environmentally relevant ratios. Methylmercury (MeHg) production by ND132 increased linearly with either SRHA or WLHPoA concentration, but SRHA, a terrestrially derived DOM, was far more effective at enhancing Hg-methylation than WLHPoA, an aquatic DOM dominated by autochthonous sources. No DOM-dependent enhancement in Hg methylation was observed in Hg–DOM–sulfide solutions amended with sufficient l-cysteine to prevent β-HgS(s) formation. We hypothesize that small HgS particles, stabilized against aggregation by DOM, are bioavailable to Hg-methylating bacteria. Our laboratory experiments provide a mechanism for the positive correlations between DOC and MeHg production observed in many aquatic sediments and wetland soils.

  8. Evidence for the Presence of Colloidal Metacinnabar in Mercury-DOM-Sulfide Systems as Determined by a Chromatographic-EXAFS Method

    Science.gov (United States)

    Gerbig, C. A.; Kim, C. S.; Moreau, J. W.; Aiken, G. R.; Krabbenhoft, D. P.; Nagy, K. L.; Ryan, J. N.

    2008-12-01

    Mercury speciation and bioavailability is frequently thought to be controlled by the presence of dissolved organic matter (DOM) and sulfide. However, the speciation of mercury in these systems is poorly understood due to the complex interactions of mercury, DOM, and sulfide. We have developed a combined chromatographic-extended x-ray absorption fine structure (EXAFS) spectroscopy approach to determine the speciation of the hydrophobic fraction of mercury species in both sulfide-free and sulfide-rich (100 μM) experimental systems that also contain dissolved organic matter isolated from several locations, including the Florida Everglades. Chromatographic experiments were carried out with and without sulfide at varied mercury concentrations ranging from 0.1 nM to 1 μM in the presence of 10 mg L-1 DOM. The method consists of equilibrating the mercury-DOM with or without sulfide for 20 h (pH 6.5, I 0.1M) followed by chromatographic fractionation and concentration on a small column of C18 resin. Greater than 80% of the mercury in all solutions was found to be hydrophobic with respect to the resin when the mercury was interacting with the strong-binding DOM sites. The chromatographic behavior of solutions with and without sulfide was distinctly different. Sulfide-free mercury-DOM systems exhibited typical chromatographic behavior exemplified by resin saturation and subsequent breakthrough of mercury species. The sulfide-rich system exhibited very high resin affinity for almost all mercury species in solution and no apparent breakthrough, regardless of the ratio of mercury to DOM. Similar chromatographic experiments were carried out with and without sulfide at mercury concentrations as low as 250 nM and a DOM concentration of 50 mg L-1. EXAFS spectroscopy at the mercury LIII edge clearly showed spectra consistent with metacinnabar (HgS) as the dominant form of mercury adsorbed to the resin under sulfidic conditions despite the fact that no bulk precipitation was observed

  9. Effect of Nitrogen Oxides on Elemental Mercury Removal by Nanosized Mineral Sulfide.

    Science.gov (United States)

    Li, Hailong; Zhu, Lei; Wang, Jun; Li, Liqing; Lee, Po-Heng; Feng, Yong; Shih, Kaimin

    2017-08-01

    Because of its large surface area, nanosized zinc sulfide (Nano-ZnS) has been demonstrated in a previous study to be efficient for removal of elemental mercury (Hg 0 ) from coal combustion flue gas. The excellent mercury adsorption performance of Nano-ZnS was found to be insusceptible to water vapor, sulfur dioxide, and hydrogen chloride. However, nitrogen oxides (NO X ) apparently inhibited mercury removal by Nano-ZnS; this finding was unlike those of many studies on the promotional effect of NO X on Hg 0 removal by other sorbents. The negative effect of NO X on Hg 0 adsorption over Nano-ZnS was systematically investigated in this study. Two mechanisms were identified as primarily responsible for the inhibitive effect of NO X on Hg 0 adsorption over Nano-ZnS: (1) active sulfur sites on Nano-ZnS were oxidized to inactive sulfate by NO X ; and (2) the chemisorbed mercury, i.e., HgS, was reduced to Hg 0 by NO X . This new insight into the role of NO X in Hg 0 adsorption over Nano-ZnS can help to optimize operating conditions, maximize Hg 0 adsorption, and facilitate the application of Nano-ZnS as a superior alternative to activated carbon for Hg 0 removal using existing particulate matter control devices in power plants.

  10. Synthesis of Black and Red Mercury Sulfide Nano-Powder by Traditional Indian Method for Biomedical Application

    International Nuclear Information System (INIS)

    Padhi, Payodhar; Sahoo, G.; Das, K.; Ghosh, Sudipto; Panigrahi, S. C.

    2008-01-01

    The use of metals and minerals in the traditional Indian system of medicine known as aired is very common and is practiced since seventh century B.C. Metals were reduced to calcined powder form for medicinal purpose. For detoxification, a further step of purification of the metals and minerals with different vegetable extracts was practiced. The people of East India were using mercury and its sulfide as medicine. Gradually this secret was leaked to Arabic physicians who used mercury in skin ointment. Subsequently Italian Physicians adopted Arabic prescriptions of mercurial ointments for skin diseases. In the olden days, metals and minerals were impregnated with decoction and juice of vegetables and animal products like milk and fat for purification. These were then reduced to fine particles by milling with a pestle and mortar. It was known by then that the fineness of the powder had a significant influence on the color, texture, and medicinal properties as is cited by Charak. Nagarjun studied in detail the processing of metals and minerals, particularly mercury and the influence of the processing parameters on the medicinal values. Mercury is unique in many aspects. Indian alchemy developed a wide variety a chemical processes for the ostensible transmutation of metals and preparation of elixir of life, in which mercury occupied a prime position .The present investigation attempts to use the traditional methods as prescribed in the ancient texts to prepare mercury sulfide in both red and black form for medicinal use. XRD, SEM and HRTEM investigations of the sulfides obtained shows that the ancient Indians were able to produce nano-sized powders. Possibly this may be taken as the earliest application of the production and use of nano powder. The study proves that even in ancient time the knowledge of nano particle synthesis was prevalent and used to enhance effectiveness of medicines. Further mercury in the free form is not acceptable in medicines. The ancient

  11. Rate of formation and dissolution of mercury sulfide nanoparticles: The dual role of natural organic matter

    Science.gov (United States)

    Slowey, Aaron J.

    2010-01-01

    Mercury is a global contaminant of concern due to its transformation by microorganisms to form methylmercury, a toxic species that accumulates in biological tissues. The effect of dissolved organic matter (DOM) isolated from natural waters on reactions between mercury(II) (Hg) and sulfide (S(-II)) to form HgS(s) nanoparticles across a range of Hg and S(-II) concentrations was investigated. Hg was equilibrated with DOM, after which S(-II) was added. Dissolved Hg (Hgaq) was periodically quantified using ultracentrifugation and chemical analysis following the addition of S(-II). Particle size and identity were determined using dynamic light scattering and X-ray absorption spectroscopy. S(-II) reacts with Hg to form 20 to 200nm aggregates consisting of 1-2 nm HgS(s) subunits that are more structurally disordered than metacinnabar in the presence of 2 x 10-9 to 8 x 10-6M Hg and 10 (mg C)L-1 DOM. Some of the HgS(s) nanoparticle aggregates are subsequently dissolved by DOM and (re)precipitated by S(-II) over periods of hours to days. At least three fractions of Hg-DOM species were observed with respect to reactivity toward S(-II): 0.3 μmol reactive Hg per mmol C (60 percent), 0.1 μmol per mmol C (20 percent) that are kinetically hindered, and another 0.1 μmol Hg per mmol C (20 percent) that are inert to reaction with S(-II). Following an initial S(-II)-driven precipitation of HgS(s), HgS(s) was dissolved by DOM or organic sulfur compounds. HgS(s) formation during this second phase was counterintuitively favored by lower S(-II) concentrations, suggesting surface association of DOM moieties that are less capable of dissolving HgS(s). DOM partially inhibits HgS(s) formation and mediates reactions between Hg and S(-II) such that HgS(s) is susceptible to dissolution. These findings indicate that Hg accessibility to microorganisms could be controlled by kinetic (intermediate) species in the presence of S(-II) and DOM, undermining the premise that equilibrium Hg species

  12. Partitioning of U, Th and K Between Metal, Sulfide and Silicate, Insights into the Volatile-Content of Mercury

    Science.gov (United States)

    Habermann, M.; Boujibar, A.; Righter, K.; Danielson, L.; Rapp, J.; Righter, M.; Pando, K.; Ross, D. K.; Andreasen, R.; Chidester, B.

    2016-01-01

    During the early stages of the Solar System formation, especially during the T-Tauri phase, the Sun emitted strong solar winds, which are thought to have expelled a portion of the volatile elements from the inner solar system. It is therefore usually believed that the volatile depletion of a planet is correlated with its proximity to the Sun. This trend was supported by the K/Th and K/U ratios of Venus, the Earth, and Mars. Prior to the MESSENGER mission, it was expected that Mercury is the most volatile-depleted planet. However, the Gamma Ray Spectrometer of MESSENGER spacecraft revealed elevated K/U and K/Th ratios for the surface of Mercury, much higher than previous expectations. It is possible that the K/Th and K/U ratios on the surface are not a reliable gauge of the bulk volatile content of Mercury. Mercury is enriched in sulfur and is the most reduced of the terrestrial planets, with oxygen fugacity (fO2) between IW-6.3 and IW-2.6 log units. At these particular compositions, U, Th and K behave differently and can become more siderophile or chalcophile. If significant amounts of U and Th are sequestered in the core, the apparent K/U and K/Th ratios measured on the surface may not represent the volatile budget of the whole planet. An accurate determination of the partitioning of these elements between silicate, metal, and sulfide phases under Mercurian conditions is therefore essential to better constrain Mercury's volatile content and assess planetary formation models.

  13. Mercury

    International Nuclear Information System (INIS)

    Vilas, F.; Chapman, C.R.; Matthews, M.S.

    1988-01-01

    Papers are presented on future observations of and missions to Mercury, the photometry and polarimetry of Mercury, the surface composition of Mercury from reflectance spectrophotometry, the Goldstone radar observations of Mercury, the radar observations of Mercury, the stratigraphy and geologic history of Mercury, the geomorphology of impact craters on Mercury, and the cratering record on Mercury and the origin of impacting objects. Consideration is also given to the tectonics of Mercury, the tectonic history of Mercury, Mercury's thermal history and the generation of its magnetic field, the rotational dynamics of Mercury and the state of its core, Mercury's magnetic field and interior, the magnetosphere of Mercury, and the Mercury atmosphere. Other papers are on the present bounds on the bulk composition of Mercury and the implications for planetary formation processes, the building stones of the planets, the origin and composition of Mercury, the formation of Mercury from planetesimals, and theoretical considerations on the strange density of Mercury

  14. Development of Nano-Sulfide Sorbent for Efficient Removal of Elemental Mercury from Coal Combustion Fuel Gas.

    Science.gov (United States)

    Li, Hailong; Zhu, Lei; Wang, Jun; Li, Liqing; Shih, Kaimin

    2016-09-06

    The surface area of zinc sulfide (ZnS) was successfully enlarged using nanostructure particles synthesized by a liquid-phase precipitation method. The ZnS with the highest surface area (named Nano-ZnS) of 196.1 m(2)·g(-1) was then used to remove gas-phase elemental mercury (Hg(0)) from simulated coal combustion fuel gas at relatively high temperatures (140 to 260 °C). The Nano-ZnS exhibited far greater Hg(0) adsorption capacity than the conventional bulk ZnS sorbent due to the abundance of surface sulfur sites, which have a high binding affinity for Hg(0). Hg(0) was first physically adsorbed on the sorbent surface and then reacted with the adjacent surface sulfur to form the most stable mercury compound, HgS, which was confirmed by X-ray photoelectron spectroscopy analysis and a temperature-programmed desorption test. At the optimal temperature of 180 °C, the equilibrium Hg(0) adsorption capacity of the Nano-ZnS (inlet Hg(0) concentration of 65.0 μg·m(-3)) was greater than 497.84 μg·g(-1). Compared with several commercial activated carbons used exclusively for gas-phase mercury removal, the Nano-ZnS was superior in both Hg(0) adsorption capacity and adsorption rate. With this excellent Hg(0) removal performance, noncarbon Nano-ZnS may prove to be an advantageous alternative to activated carbon for Hg(0) removal in power plants equipped with particulate matter control devices, while also offering a means of reusing fly ash as a valuable resource, for example as a concrete additive.

  15. Experimental Behavior of Sulfur Under Primitive Planetary Differentiation Processes, the Sulfide Formations in Enstatite Meteorites and Implications for Mercury.

    Science.gov (United States)

    Malavergne, V.; Brunet, F.; Righter, K.; Zanda, B.; Avril, C.; Borensztajn, S.; Berthet, S.

    2012-01-01

    Enstatite meteorites are the most reduced naturally-occuring materials of the solar system. The cubic monosulfide series with the general formula (Mg,Mn,Ca,Fe)S are common phases in these meteorite groups. The importance of such minerals, their formation, composition and textural relationships for understanding the genesis of enstatite chondrites (EC) and aubrites, has long been recognized (e.g. [1]). However, the mechanisms of formation of these sulfides is still not well constrained certainly because of possible multiple ways to produce them. We propose to simulate different models of formation in order to check their mineralogical, chemical and textural relevancies. The solubility of sulfur in silicate melts is of primary interest for planetary mantles, particularly for the Earth and Mercury. Indeed, these two planets could have formed, at least partly, from EC materials (e.g. [2, 3, 4]). The sulfur content in silicate melts depends on the melt composition but also on pressure (P), temperature (T) and oxygen fugacity fO2. Unfortunately, there is no model of general validity in a wide range of P-T-fO2-composition which describes precisely the evolution of sulfur content in silicate melts, even if the main trends are now known. The second goal of this study is to constrain the sulfur content in silicate melts under reducing conditions and different temperatures.

  16. Mercury

    NARCIS (Netherlands)

    de Vries, Irma

    2017-01-01

    Mercury is a naturally occurring metal that exists in several physical and chemical forms. Inorganic mercury refers to compounds formed after the combining of mercury with elements such as chlorine, sulfur, or oxygen. After combining with carbon by covalent linkage, the compounds formed are called

  17. Mackinawite (FeS) reduces mercury(II) under sulfidic conditions.

    Science.gov (United States)

    Bone, Sharon E; Bargar, John R; Sposito, Garrison

    2014-09-16

    Mercury (Hg) is a toxicant of global concern that accumulates in organisms as methyl Hg. The production of methyl Hg by anaerobic bacteria may be limited in anoxic sediments by the sequestration of divalent Hg [Hg(II)] into a solid phase or by the formation of elemental Hg [Hg(0)]. We tested the hypothesis that nanocrystalline mackinawite (tetragonal FeS), which is abundant in sediments where Hg is methylated, both sorbs and reduces Hg(II). Mackinawite suspensions were equilibrated with dissolved Hg(II) in batch reactors. Examination of the solid phase using Hg LIII-edge extended X-ray absorption fine structure (EXAFS) spectroscopy showed that Hg(II) was indeed reduced in FeS suspensions. Measurement of purgeable Hg using cold vapor atomic fluorescence spectrometry (CVAFS) from FeS suspensions and control solutions corroborated the production of Hg(0) that was observed spectroscopically. However, a fraction of the Hg(II) initially added to the suspensions remained in the divalent state, likely in the form of β-HgS-like clusters associated with the FeS surface or as a mixture of β-HgS and surface-associated species. Complexation by dissolved S(-II) in anoxic sediments hinders Hg(0) formation, but, by contrast, Hg(II)-S(-II) species are reduced in the presence of mackinawite, producing Hg(0) after only 1 h of reaction time. The results of our work support the idea that Hg(0) accounts for a significant fraction of the total Hg in wetland and estuarine sediments.

  18. Mercury

    Science.gov (United States)

    ... build up in fish, shellfish, and animals that eat fish. The nervous system is sensitive to all forms of mercury. Exposure to high levels can damage the brain and kidneys. Pregnant women can pass the mercury in their bodies to their babies. It is important to protect your family from ...

  19. Mercury

    Science.gov (United States)

    ... has set a limit of 2 parts of mercury per billion parts of drinking water (2 ppb). The Food and Drug Administration (FDA) has set a maximum permissible level of 1 part of methylmercury in a million ... of 0.1 milligram of organic mercury per cubic meter of workplace air (0.1 ...

  20. Mercury contamination extraction

    Science.gov (United States)

    Fuhrmann, Mark [Silver Spring, MD; Heiser, John [Bayport, NY; Kalb, Paul [Wading River, NY

    2009-09-15

    Mercury is removed from contaminated waste by firstly applying a sulfur reagent to the waste. Mercury in the waste is then permitted to migrate to the reagent and is stabilized in a mercury sulfide compound. The stable compound may then be removed from the waste which itself remains in situ following mercury removal therefrom.

  1. Mercury

    CERN Document Server

    Balogh, André; Steiger, Rudolf

    2008-01-01

    Mercury, the planet closest to the Sun, is different in several respects from the other three terrestrial planets. In appearance, it resembles the heavily cratered surface of the Moon, but its density is high, it has a magnetic field and magnetosphere, but no atmosphere or ionosphere. This book reviews the progress made in Mercury studies since the flybys by Mariner 10 in 1974-75, based on the continued research using the Mariner 10 archive, on observations from Earth, and on increasingly realistic models of its interior evolution.

  2. Metal-Silicate-Sulfide Partitioning of U, Th, and K: Implications for the Budget of Volatile Elements in Mercury

    Science.gov (United States)

    Habermann, M.; Boujibar, A.; Righter, K.; Danielson, L.; Rapp, J.; Righter, M.; Pando, K.; Ross, D. K.; Andreasen, R.

    2016-01-01

    During formation of the solar system, the Sun produced strong solar winds, which stripped away a portion of the volatile elements from the forming planets. Hence, it was expected that planets closest to the sun, such as Mercury, are more depleted in volatile elements in comparison to other terrestrial planets. However, the MESSENGER mission detected higher than expected K/U and K/Th ratios on Mercury's surface, indicating a volatile content between that of Mars and Earth. Our experiments aim to resolve this discrepancy by experimentally determining the partition coefficients (D(sup met/sil)) of K, U, and Th between metal and silicate at varying pressure (1 to 5 GPa), temperature (1500 to 1900 C), oxygen fugacity (IW-2.5 to IW-6.5) and sulfur-content in the metal (0 to 33 wt%). Our data show that U, Th, and K become more siderophile with decreasing fO2 and increasing sulfur-content, with a stronger effect for U and Th in comparison to K. Using these results, the concentrations of U, Th, and K in the bulk planet were calculated for different scenarios, where the planet equilibrated at a fO2 between IW-4 and IW-7, assuming the existence of a FeS layer, between the core and mantle, with variable thickness. These models show that significant amounts of U and Th are partitioned into Mercury's core. The elevated superficial K/U and K/Th values are therefore only a consequence of the sequestration of U and Th into the core, not evidence of the overall volatile content of Mercury.

  3. Apparatus for control of mercury

    Science.gov (United States)

    Downs, William; Bailey, Ralph T.

    2001-01-01

    A method and apparatus for reducing mercury in industrial gases such as the flue gas produced by the combustion of fossil fuels such as coal adds hydrogen sulfide to the flue gas in or just before a scrubber of the industrial process which contains the wet scrubber. The method and apparatus of the present invention is applicable to installations employing either wet or dry scrubber flue gas desulfurization systems. The present invention uses kraft green liquor as a source for hydrogen sulfide and/or the injection of mineral acids into the green liquor to release vaporous hydrogen sulfide in order to form mercury sulfide solids.

  4. Process for removing mercury from aqueous solutions

    Science.gov (United States)

    Googin, John M.; Napier, John M.; Makarewicz, Mark A.; Meredith, Paul F.

    1986-01-01

    A process for removing mercury from water to a level not greater than two parts per billion wherein an anion exchange material that is insoluble in water is contacted first with a sulfide containing compound and second with a compound containing a bivalent metal ion forming an insoluble metal sulfide. To this treated exchange material is contacted water containing mercury. The water containing not more than two parts per billion of mercury is separated from the exchange material.

  5. Attenuation by methyl mercury and mercuric sulfide of pentobarbital induced hypnotic tolerance in mice through inhibition of ATPase activities and nitric oxide production in cerebral cortex

    Energy Technology Data Exchange (ETDEWEB)

    Chuu, Jiunn-Jye; Huang, Zih-Ning; Yu, Hsun-Hsin; Chang, Liang-Hao [College of Engineering, Southern Taiwan University, Institute of Biotechnology, Tainan (China); Lin-Shiau, Shoei-Yn [College of Medicine, National Taiwan University, Institute of Pharmacology, Taipei (China)

    2008-06-15

    This study is aimed at exploring the possible mechanism of hypnosis-enhancing effect of HgS or cinnabar (a traditional Chinese medicine containing more than 95% HgS) in mice treated with pentobarbital. We also examined whether the effect of HgS is different from that of the well-known methyl mercury (MeHg). After a short period (7 days) of oral administration to mice, a nontoxic dose (0.1 g/kg) of HgS not only significantly enhanced pentobarbital-induced hypnosis but also attenuated tolerance induction; while a higher dose (1 g/kg) of HgS or cinnabar exerted an almost irreversible enhancing effect on pentobarbital-hypnosis similar to that of MeHg (2 mg/kg) tested, which was still effective even after 10 or 35 days cessation of administration. To study comparatively the effects of different mercury forms from oral administration of MeHg and HgS on membrane ATPase activities of experimental mice, analysis of the Hg content in the cerebral cortex revealed that correlated with the decrease of Na{sup +}/K{sup +}-ATPase and Ca{sup 2+}-ATPase activities. Furthermore, NO levels of blood but not that of cerebral cortex were also decreased by mercuric compounds. Although pentobarbital alone enhanced cytochrome p450-2C9 in time dependent manner, all of mercurial compounds tested had no such effect. All of these findings indicated that the mercurial compounds including cinnabar, HgS and MeHg exert a long-lasting enhancing hypnotic activity without affecting pentobarbital metabolism, which provides evidence-based sedative effect of cinnabar used in Chinese traditional medicine for more than 2,000 years. The nontoxic HgS dosing (0.1 g/kg/day) for consecutive 7 days is perhaps useful for delaying or preventing pentobarbital-tolerance. (orig.)

  6. Determination of hydrogen sulfide and volatile thiols in air samples by mercury probe derivatization coupled with liquid chromatography-atomic fluorescence spectrometry.

    Science.gov (United States)

    Bramanti, Emilia; D'Ulivo, Lucia; Lomonte, Cristina; Onor, Massimo; Zamboni, Roberto; Raspi, Giorgio; D'Ulivo, Alessandro

    2006-10-02

    A new procedure is proposed for the sampling and storage of hydrogen sulphide (H2S) and volatile thiols (methanethiol or methyl mercaptan, ethanethiol and propanethiol) for their determination by liquid chromatography. The sampling procedure is based on the trapping/pre-concentration of the analytes in alkaline aqueous solution containing an organic mercurial probe p-hydroxymercurybenzoate, HO-Hg-C6H4-COO- (PHMB), where they are derivatized to stable PHMB complexes based on mercury-sulfur covalent bonds. PHMB complexes are separated on a C18 reverse phase column, allowing their determination by liquid chromatography coupled with sequential non-selective UV-vis (DAD) and mercury specific (chemical vapor generation atomic fluorescence spectrometry, CVGAFS) on-line detectors. PHMB complexes, S(PHMB)2CH3S-PHMB, C2H5S-PHMB and C3H7S-PHMB, are stable alt least for 12 h at room temperature and for 3 months if stored frozen (-20 degrees C). The best analytical figures of merits in the optimized conditions were obtained by CVGAFS detection, with detection limits (LODc) of 9.7 microg L(-1) for H2S, 13.7 microg L(-1) for CH(3)SH, 17.7 microg L(-1) for C2H5SH and 21.7 microg L(-1) for C3H7SH in the trapping solution in form of RS-PHMB complexes, the relative standard deviation (R.S.D.) ranging between 1.0 and 1.5%, and a linear dynamic range (LDR) between 10 and 9700 microg L(-1). Conventional UV absorbance detectors tuned at 254 nm can be employed as well with comparable R.S.D. and LDR, but with LODc one order of magnitude higher than AFS detector and lower specificity. The sampling procedure followed by LC-DAD-CVGAFS analysis has been validated, as example, for H2S determination by a certified gas permeation tube as a source of 3.071+/-0.154 microg min(-1) of H2S, giving a recovery of 99.8+/-7% and it has been applied to the determination of sulfur compounds in real gas samples (biogas and the air of a plant for fractional distillation of crude oil).

  7. Stabilization of Mercury in High pH Tank Sludges

    Energy Technology Data Exchange (ETDEWEB)

    Spence, R.; Barton, J.

    2003-02-24

    DOE complex contains many tank sludges contaminated with mercury. The high pH of these tank sludges typically fails to stabilize the mercury, resulting in these radioactive wastes also being characteristically hazardous or mixed waste. The traditional treatment for soluble inorganic mercury species is precipitation as insoluble mercuric sulfide. Sulfide treatment and a commercial mercury-stabilizing product were tested on surrogate sludges at various alkaline pH values. Neither the sulfide nor the commercial product stabilized the mercury sufficiently at the high pH of the tank sludges to pass the Toxicity Characteristic Leach Procedure (TCLP) treatment standards of the Resource Conservation and Recovery Act (RCRA). The commercial product also failed to stabilize the mercury in samples of the actual tank sludges.

  8. Mercury Methylation and Detoxification by Novel Microorganisms in Mercury Enriched Mesothermal Springs

    Science.gov (United States)

    Gionfriddo, C. M.; Krabbenhoft, D. P.; Stott, M.; Wick, R. R.; Schultz, M. B.; Holt, K. E.; Moreau, J. W.

    2015-12-01

    Hot springs and fumaroles release significant quantities of aqueous and gaseous mercury into the environment. Yet few studies have looked at the microbial underpinnings of mercury transformations in geothermal settings. Recent advancements in culture-independent molecular techniques, such as ultra-high-throughput sequencing, allow us to delve deeply into the functional and phylogenetic make-up of these extreme environments. Here we present results from deep metagenomic sequencing of geothermal microbial communities cycling mercury, focussing on the connections between putative metabolisms and mercury methylation, and the evolution of the mer-operon. Presented are data from two adjacent, acidic (pHNew Zealand), extremely enriched in total mercury (>1000 ng L-1), and varying methylmercury concentrations (1-10 ng L-1). Microbial communities of both springs are dominated by mercury resistant acidophilic, sulfur- and iron-cycling microbes: Acidithiobacillus, Thiomonas, and Thermoplasma. Mercury methylation genes (hgcAB) were only detected in the cooler spring (ΔT~10 °C), with an order of magnitude greater methylmercury (10 ng L-1). The hgcAB genes have no known closest relatives (40°C), and methylmercury concentration. We conclude that the relative amount of mercury methylation in each hot spring is controlled by the presence of methylating bacteria and archaea, the release of bioavailable mercury species from sulfide minerals, counterbalanced by microbial mercury demethylation and reduction and mercury sulfide mineralization.

  9. STABILIZATION AND TESTING OF MERCURY CONTAINING WASTES: BORDEN SLUDGE

    Science.gov (United States)

    This report details the stability assessment of a mercury containing sulfide treatment sludge. Information contained in this report will consist of background data submitted by the geneerator, landfill data supplied by EPA and characterization and leaching studies conducted by UC...

  10. Sulfide chemiluminescence detection

    Science.gov (United States)

    Spurlin, S.R.; Yeung, E.S.

    1985-11-26

    A method is described for chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction. 4 figs.

  11. Complex sulfides and thiosalts

    International Nuclear Information System (INIS)

    Uehlls, A.

    1987-01-01

    Different types of the structures of complex sulfides, thiosalts of alkali, alkaline earth, rare earth, transition and actinide metals are considered in the review of the papers published before 1980 and devoted to the crystal structure of complex sulfides

  12. Mercury and Your Health

    Science.gov (United States)

    ... the Risk of Exposure to Mercury Learn About Mercury What is Mercury What is Metallic mercury? Toxicological Profile ToxFAQs Mercury Resources CDC’s National Biomonitoring Program Factsheet on Mercury ...

  13. Got Mercury?

    Science.gov (United States)

    Meyers, Valerie E.; McCoy, J. Torin; Garcia, Hector D.; James, John T.

    2009-01-01

    Many of the operational and payload lighting units used in various spacecraft contain elemental mercury. If these devices were damaged on-orbit, elemental mercury could be released into the cabin. Although there are plans to replace operational units with alternate light sources, such as LEDs, that do not contain mercury, mercury-containing lamps efficiently produce high quality illumination and may never be completely replaced on orbit. Therefore, exposure to elemental mercury during spaceflight will remain possible and represents a toxicological hazard. Elemental mercury is a liquid metal that vaporizes slowly at room temperature. However, it may be completely vaporized at the elevated operating temperatures of lamps. Although liquid mercury is not readily absorbed through the skin or digestive tract, mercury vapors are efficiently absorbed through the respiratory tract. Therefore, the amount of mercury in the vapor form must be estimated. For mercury releases from lamps that are not being operated, we utilized a study conducted by the New Jersey Department of Environmental Quality to calculate the amount of mercury vapor expected to form over a 2-week period. For longer missions and for mercury releases occurring when lamps are operating, we conservatively assumed complete volatilization of the available mercury. Because current spacecraft environmental control systems are unable to remove mercury vapors, both short-term and long-term exposures to mercury vapors are possible. Acute exposure to high concentrations of mercury vapors can cause irritation of the respiratory tract and behavioral symptoms, such as irritability and hyperactivity. Chronic exposure can result in damage to the nervous system (tremors, memory loss, insomnia, etc.) and kidneys (proteinurea). Therefore, the JSC Toxicology Group recommends that stringent safety controls and verifications (vibrational testing, etc.) be applied to any hardware that contains elemental mercury that could yield

  14. Mobilization of mercury from sediments into guppies (Poecilia reticulata)

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, D.C.

    1972-01-01

    Guppies (P. reticulata) were exposed in aquaria to aerobic and anaerobic sediments to which various forms of mercury were added and to sediments from two sites of industrial pollution. Whole body levels of total mercury (atomic absorption analysis) in these fish were used as a measure of mobilization of mercury from these sediments. Spot checks for methylmercury were carried out at intervals during the tests. Under aerobic conditions there was little mobilization of mercury from sediments to which mercuric chloride or sulfide had been added but total mercury concentrations rose rapidly in fish exposed to sediments containing metallic mercury. The proportion of methylmercury in fish reached maxima of 30% for metallic mercury, 40% for mercuric chloride, and 45% for mercuric sulfide. In anaerobic sediments, total mobilization was low and only mercuric chloride was significantly methylated (40% of the total in the fish). Both mobilization and methylation were proportionately greater in industrial sediments with a low mercury content than in sediments with a higher mercury content. Enrichment of sediments with lignosulfonate showed no real effects aerobically, possibly because of the chelation properties of the preparation used. Anaerobically, lignosulfonate stimulated methylation of mercury. 14 references, 3 figures, 3 tables.

  15. Accumulation of mercury in selected plant species grown in soils contaminated with different mercury compounds

    International Nuclear Information System (INIS)

    Su, Yi; Han, Fengxiang; Shiyab, Safwan; Chen, Jian; Monts, David L.

    2007-01-01

    of ppm mercury can be accumulated in the roots of Indian mustard plants grown with soil contaminated by mercury sulfide; HgS is assumed to be the most stable and also the predominant mercury form in flood plain soils. We have also started to investigate different mercury uptake mechanisms, such as root uptake of soil contaminant and foliar mercury accumulation from ambient air. We have observed mercury translocation from roots to shoot for Chinese fern and two Indian mustard varieties. (authors)

  16. Basic Information about Mercury

    Science.gov (United States)

    ... Your Environment Contact Us Share Basic Information about Mercury On this page: What is mercury? Emissions of ... Consumer products that traditionally contain mercury What is Mercury? Mercury is a naturally-occurring chemical element found ...

  17. Mercury toxicity and neurodegenerative effects.

    Science.gov (United States)

    Carocci, Alessia; Rovito, Nicola; Sinicropi, Maria Stefania; Genchi, Giuseppe

    2014-01-01

    Mercury is among the most toxic heavy metals and has no known physiological role in humans. Three forms of mercury exist: elemental, inorganic and organic. Mercury has been used by man since ancient times. Among the earliest were the Chinese and Romans, who employed cinnabar (mercury sulfide) as a red dye in ink (Clarkson et al. 2007). Mercury has also been used to purify gold and silver minerals by forming amalgams. This is a hazardous practice, but is still widespread in Brazil's Amazon basin, in Laos and in Venezuela, where tens of thousands of miners are engaged in local mining activities to find and purify gold or silver. Mercury compounds were long used to treat syphilis and the element is still used as an antiseptic,as a medicinal preservative and as a fungicide. Dental amalgams, which contain about 50% mercury, have been used to repair dental caries in the U.S. since 1856.Mercury still exists in many common household products around the world.Examples are: thermometers, barometers, batteries, and light bulbs (Swain et al.2007). In small amounts, some organo mercury-compounds (e.g., ethylmercury tiosalicylate(thimerosal) and phenylmercury nitrate) are used as preservatives in some medicines and vaccines (Ballet al. 2001).Each mercury form has its own toxicity profile. Exposure to Hg0 vapor and MeHg produce symptoms in CNS, whereas, the kidney is the target organ when exposures to the mono- and di-valent salts of mercury (Hg+ and Hg++, respectively)occur. Chronic exposure to inorganic mercury produces stomatitis, erethism and tremors. Chronic MeHg exposure induced symptoms similar to those observed in ALS, such as the early onset of hind limb weakness (Johnson and Atchison 2009).Among the organic mercury compounds, MeHg is the most biologically available and toxic (Scheuhammer et a!. 2007). MeHg is neurotoxic, reaching high levels of accumulation in the CNS; it can impair physiological function by disrupting endocrine glands (Tan et a!. 2009).The most

  18. Cytochemical demonstration of mercury deposits in trout liver and kidney following methyl mercury intoxication: differentiation of two mercury pools by selenium

    DEFF Research Database (Denmark)

    Baatrup, E; Danscher, G

    1988-01-01

    The amount and the ultrastructural distribution of mercury was studied in seven different organs of rainbow trout (Salmo gairdneri) fingerlings following exposure to methyl mercury (MeHg)-contaminated fodder for periods of 2 and 7 weeks. The amounts of mercury retained by the whole fish...... and the selected organs were determined by measuring the uptake of 203Hg-labeled MeHg. Spleen, liver, and kidney had the highest concentrations after both experimental periods, while the largest relative increases were found in brain, muscle, and kidney. The subcellular distribution of mercury accumulations...... was demonstrated cytochemically in liver and kidney using the silver enhancement method by which accumulations of mercury-sulfides and/or mercury-selenides are made visible for light and electron microscopy. When sections prepared from the liver and kidney from fish, injected with selenium 2 hr prior to being...

  19. The influence of floodplains on mercury availability

    Energy Technology Data Exchange (ETDEWEB)

    Wallschlaeger, D.; Wilken, R.D. [GKSS Research Center, Geesthacht (Germany). Inst. of Physical and Chemical Analytics

    1997-09-01

    The floodplains of the German river Elbe affect the mercury distribution in the river system in two different ways: they act both as a medium-term sink and as a long-term source. The large amounts of mercury deposited onto the floodplains during annual floodings are first effectively fixed in the soils, rendering them basically unavailable. Sequential extraction experiments reveal that only a small fraction of the mercury (< 3%) is present in available forms, whereas the vast majority is associated with humic substances or present in sulfidic binding forms. After deposition, a small fraction of the total mercury is gradually remobilized into the aqueous phase bound passively to water-soluble humic acids. The availability of mercury in these complexes is still low, since environmental influences such as changes in pH or redox potential and competition with other cations do not cause any mercury liberation. In the next step, reactions in the aqueous phase lead to the formation of the highly available volatile species Hg{sup 0} and dimethylmercury (DMM). Their evaporation gives rise to a strong mercury flux from the floodplains into the atmosphere. Preliminary mass balances indicate that the majority of the deposited mercury stays bound in the floodplain soils, while small amounts are emitted back into the river`s ecosystem. Atmospheric emission is more important as a remobilization pathway than aquatic export.

  20. Antitumor Allium Sulfides.

    Science.gov (United States)

    Nohara, Toshihiro; Fujiwara, Yukio; El-Aasr, Mona; Ikeda, Tsuyoshi; Ono, Masateru; Nakano, Daisuke; Kinjo, Junei

    2017-01-01

    We examined the sulfides in onion (Allium cepa L.), Welsh onion (A. fistulosum L.), and garlic (A. sativum L.), and obtained three new thiolane-type sulfides (onionins A 1 -A 3 ) from onion; two new thiabicyclic-type sulfides (welsonins A 1 , A 2 ), together with onionins A 1 -A 3 , from Welsh onion; and six new acyclic-type sulfides (garlicnins L-1-L-4, E, and F), ten new thiolane-type sulfides (garlicnins A, B 1 -B 4 , C 1 -C 3 , K 1 , and K 2 ), and three new atypical cyclic-type sulfides (garlicnins G, I, and J) from garlic. Acetone extracts showed the potential of these sulfides in inhibiting the polarization of M2 activated macrophages that are capable of suppressing tumor-cell proliferation. The effect of the thiolane-type sulfide of a major component, onionin A 1 , on tumor progression and metastasis in both osteosarcoma and ovarian cancer-bearing mouse models was then examined. Tumor proliferation was depressed, and tumor metastasis was controlled by regulating macrophage activation. These results showed that onionin A 1 is an effective agent for controlling tumors in both in vitro and in vivo models, and that the antitumor effects observed in vivo are likely caused by reversing the antitumor immune system. Activation of the antitumor immune system by onionin A 1 might be an effective adjuvant therapy for patients with osteosarcoma, ovarian cancer and other malignant tumors. Based on these findings, pharmacological investigations will be conducted in the future to develop natural and healthy foods and anti-cancer agents that can prevent or combat disease.

  1. Mercury removal from natural gas and associated condensates

    Energy Technology Data Exchange (ETDEWEB)

    Hennico, A.; Barthel, Y.; Courty, P. (Institut Francais du Petrole, 31 - Rueil-Malmaison (France). Direction Industrielle)

    1990-01-01

    IFP mercury trapping systems are based on CMG 273, the recently developed Procatalyse product which is the heart of IFP's gas phase and liquid phase mercury removal technology. This material, made of highly macroporous alumina supporting a metal sulfide, presents a very high reactivity towards mecury within a broad range of operating conditions, including those operating in the liquid phase. Characteristics of CMG 273 are presented. (orig.).

  2. Mercury and Pregnancy

    Science.gov (United States)

    ... Home > Pregnancy > Is it safe? > Mercury and pregnancy Mercury and pregnancy E-mail to a friend Please ... vision problems. How can you be exposed to mercury? Mercury has several forms: It can be a ...

  3. Final disposal options for mercury/uranium mixed wastes from the Oak Ridge Reservation

    International Nuclear Information System (INIS)

    Gorin, A.H.; Leckey, J.H.; Nulf, L.E.

    1994-01-01

    Laboratory testing was completed on chemical stabilization and physical encapsulation methods that are applicable (to comply with federal and state regulations) to the final disposal of both hazardous and mixed hazardous elemental mercury waste that is in either of the following categories: (1) waste generated during decontamination and decommissioning (D and D) activities on mercury-contaminated buildings, such as Building 9201-4 at the Oak Ridge Y-12 Plant, or (2) waste stored and regulated under either the Federal Facilities Compliance Agreement or the Federal Facilities Compliance Act. Methods were used that produced copper-mercury, zinc-mercury, and sulfur-mercury materials at room temperature by dry mixing techniques. Toxicity Characteristic Leaching Procedure (TCLP) results for mercury on batches of both the copper-mercury and the sulfur-mercury amalgams consistently produced leachates with less than the 0.2-mg/L Resource Conservation and Recovery Act (RCRA) regulatory limit for mercury. The results clearly showed that the reaction of mercury with sulfur at room temperature produces black mercuric sulfide, a material that is well suited for land disposal. The results also showed that the copper-mercury and zinc-mercury amalgams had major adverse properties that make them undesirable for land disposal. In particular, they reacted readily in air to form oxides and liberate elemental mercury. Another major finding of this study is that sulfur polymer cement is potentially useful as a physical encapsulating agent for mercuric sulfide. This material provides a barrier in addition to the chemical stabilization that further prevents mercury, in the form of mercuric sulfide, from migrating into the environment

  4. How Mercury can be the most reduced terrestrial planet and still store iron in its mantle

    Science.gov (United States)

    Malavergne, Valérie; Cordier, Patrick; Righter, Kevin; Brunet, Fabrice; Zanda, Brigitte; Addad, Ahmed; Smith, Thomas; Bureau, Hélène; Surblé, Suzy; Raepsaet, Caroline; Charon, Emeline; Hewins, Roger H.

    2014-05-01

    Mercury is notorious as the most reduced planet with the highest metal/silicate ratio, yet paradoxically data from the MESSENGER spacecraft show that its iron-poor crust is high in sulfur (up to ˜6 wt%, ˜80× Earth crust abundance) present mainly as Ca-rich sulfides on its surface. These particularities are simply impossible on the other terrestrial planets. In order to understand the role played by sulfur during the formation of Mercury, we investigated the phase relationships in Mercurian analogs of enstatite chondrite-like composition experimentally under conditions relevant to differentiation of Mercury (˜1 GPa and 1300-2000 °C). Our results show that Mg-rich and Ca-rich sulfides, which both contain Fe, crystallize successively from reduced silicate melts upon cooling below 1550 °C. As the iron concentration in the reduced silicates stays very low (≪1 wt%), these sulfides represent new host phases for both iron and sulfur in the run products. Extrapolated to Mercury, these results show that Mg-rich sulfide crystallization provides the first viable and fundamental means for retaining iron as well as sulfur in the mantle during differentiation, while sulfides richer in Ca would crystallize at shallower levels. The distribution of iron in the differentiating mantle of Mercury was mainly determined by its partitioning between metal (or troilite) and Mg-Fe-Ca-rich sulfides rather than by its partitioning between metal (or troilite) and silicates. Moreover, the primitive mantle might also be boosted in Fe by a reaction at the core mantle boundary (CMB) between Mg-rich sulfides of the mantle and FeS-rich outer core materials to produce (Fe, Mg)S. The stability of Mg-Fe-Ca-rich sulfides over a large range of depths up to the surface of Mercury would be consistent with sulfur, calcium and iron abundances measured by MESSENGER.

  5. Titanocene sulfide chemistry

    Czech Academy of Sciences Publication Activity Database

    Horáček, Michal

    2016-01-01

    Roč. 314, MAY 2016 (2016), s. 83-102 ISSN 0010-8545 R&D Projects: GA ČR(CZ) GAP207/12/2368 Institutional support: RVO:61388955 Keywords : titanocene sulfide chemistry * photolysis * titanocene hydrosulfides Ti-(SH)n Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 13.324, year: 2016

  6. Sulfidation kinetics of silver nanoparticles reacted with metal sulfides.

    Science.gov (United States)

    Thalmann, Basilius; Voegelin, Andreas; Sinnet, Brian; Morgenroth, Eberhard; Kaegi, Ralf

    2014-05-06

    Recent studies have documented that the sulfidation of silver nanoparticles (Ag-NP), possibly released to the environment from consumer products, occurs in anoxic zones of urban wastewater systems and that sulfidized Ag-NP exhibit dramatically reduced toxic effects. However, whether Ag-NP sulfidation also occurs under oxic conditions in the absence of bisulfide has not been addressed, yet. In this study we, therefore, investigated whether metal sulfides that are more resistant toward oxidation than free sulfide, could enable the sulfidation of Ag-NP under oxic conditions. We reacted citrate-stabilized Ag-NP of different sizes (10-100 nm) with freshly precipitated and crystalline CuS and ZnS in oxygenated aqueous suspensions at pH 7.5. The extent of Ag-NP sulfidation was derived from the increase in dissolved Cu(2+) or Zn(2+) over time and linked with results from X-ray absorption spectroscopy (XAS) analysis of selected samples. The sulfidation of Ag-NP followed pseudo first-order kinetics, with rate coefficients increasing with decreasing Ag-NP diameter and increasing metal sulfide concentration and depending on the type (CuS and ZnS) and crystallinity of the reacting metal sulfide. Results from analytical electron microscopy revealed the formation of complex sulfidation patterns that seemed to follow preexisting subgrain boundaries in the pristine Ag-NP. The kinetics of Ag-NP sulfidation observed in this study in combination with reported ZnS and CuS concentrations and predicted Ag-NP concentrations in wastewater and urban surface waters indicate that even under oxic conditions and in the absence of free sulfide, Ag-NP can be transformed into Ag2S within a few hours to days by reaction with metal sulfides.

  7. Gravity field and internal structure of Mercury from MESSENGER.

    Science.gov (United States)

    Smith, David E; Zuber, Maria T; Phillips, Roger J; Solomon, Sean C; Hauck, Steven A; Lemoine, Frank G; Mazarico, Erwan; Neumann, Gregory A; Peale, Stanton J; Margot, Jean-Luc; Johnson, Catherine L; Torrence, Mark H; Perry, Mark E; Rowlands, David D; Goossens, Sander; Head, James W; Taylor, Anthony H

    2012-04-13

    Radio tracking of the MESSENGER spacecraft has provided a model of Mercury's gravity field. In the northern hemisphere, several large gravity anomalies, including candidate mass concentrations (mascons), exceed 100 milli-Galileos (mgal). Mercury's northern hemisphere crust is thicker at low latitudes and thinner in the polar region and shows evidence for thinning beneath some impact basins. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/MR(2) = 0.353 ± 0.017, where M and R are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of C(m)/C = 0.452 ± 0.035. A model for Mercury's radial density distribution consistent with these results includes a solid silicate crust and mantle overlying a solid iron-sulfide layer and an iron-rich liquid outer core and perhaps a solid inner core.

  8. Biogeochemical controls on mercury methylation in the Allequash Creek wetland.

    Science.gov (United States)

    Creswell, Joel E; Shafer, Martin M; Babiarz, Christopher L; Tan, Sue-Zanne; Musinsky, Abbey L; Schott, Trevor H; Roden, Eric E; Armstrong, David E

    2017-06-01

    We measured mercury methylation potentials and a suite of related biogeochemical parameters in sediment cores and porewater from two geochemically distinct sites in the Allequash Creek wetland, northern Wisconsin, USA. We found a high degree of spatial variability in the methylation rate potentials but no significant differences between the two sites. We identified the primary geochemical factors controlling net methylmercury production at this site to be acid-volatile sulfide, dissolved organic carbon, total dissolved iron, and porewater iron(II). Season and demethylation rates also appear to regulate net methylmercury production. Our equilibrium speciation modeling demonstrated that sulfide likely regulated methylation rates by controlling the speciation of inorganic mercury and therefore its bioavailability to methylating bacteria. We found that no individual geochemical parameter could explain a significant amount of the observed variability in mercury methylation rates, but we found significant multivariate relationships, supporting the widely held understanding that net methylmercury production is balance of several simultaneously occurring processes.

  9. Mercury speciation during in situ thermal desorption in soil

    International Nuclear Information System (INIS)

    Park, Chang Min; Katz, Lynn E.; Liljestrand, Howard M.

    2015-01-01

    Highlights: • Impact of soil conditions on distribution and phase transitions of Hg was identified. • Metallic Hg was slowly transformed to Hg 0 gas until the temperature reached 358.15 K. • Phase change of HgCl 2(s) completely occurred without decomposition at 335.15 K. • HgS remained solid in dry soil sharply decreased in the narrow temperature range. • Hg gas can be easily captured with higher vapor pressures of soil compositions. - Abstract: Metallic mercury (Hg 0 ) and its compounds are highly mobile and toxic environmental pollutants at trace level. In situ thermal desorption (ISTD) is one of the soil remediation processes applying heat and vacuum simultaneously. Knowledge of thermodynamic mercury speciation is imperative to understand the fate and transport of mercury during thermal remediation and operate the treatment processes in a cost-effective manner. Hence, speciation model for inorganic mercury was developed over a range of environmental conditions to identify distribution of dissolved mercury species and potential transformations of mercury at near source environment. Simulation of phase transitions for metallic mercury, mercury(II) chloride and mercury sulfide with temperature increase showed that complete vaporization of metallic mercury and mercury(II) chloride were achieved below the boiling point of water. The effect of soil compositions on mercury removal was also evaluated to better understand thermal remediation process. Higher vapor pressures expected both from soil pore water and inorganic carbonate minerals in soil as well as creation of permeability were significant for complete vaporization and removal of mercury.

  10. Mercury's Messenger

    Science.gov (United States)

    Chapman, Clark R.

    2004-01-01

    Forty years after Mariner 2, planetary exploration has still only just begun, and many more missions are on drawing boards, nearing the launch pad, or even en route across interplanetary space to their targets. One of the most challenging missions that will be conducted this decade is sending the MESSENGER spacecraft to orbit the planet Mercury.…

  11. Mercury Report-Children's exposure to elemental mercury

    Science.gov (United States)

    ... gov . Mercury Background Mercury Report Additional Resources Mercury Report - Children's Exposure to Elemental Mercury Recommend on Facebook ... I limit exposure to mercury? Why was the report written? Children attending a daycare in New Jersey ...

  12. Suicide with hydrogen sulfide.

    Science.gov (United States)

    Sams, Ralph Newton; Carver, H Wayne; Catanese, Charles; Gilson, Thomas

    2013-06-01

    This presentation will address the recent rise of suicide deaths resulting from the asphyxiation by hydrogen sulfide (H2S) gas.Hydrogen sulfide poisoning has been an infrequently encountered cause of death in medical examiner practice. Most H2S deaths that have been reported occurred in association with industrial exposure.More recently, H2S has been seen in the commission of suicide, particularly in Japan. Scattered reports of this phenomenon have also appeared in the United States.We have recently observed 2 intentional asphyxial deaths in association with H2S. In both cases, the decedents committed suicide in their automobiles. They generated H2S by combining a sulfide-containing tree spray with toilet bowl cleaner (with an active ingredient of hydrogen chloride acid). Both death scenes prompted hazardous materials team responses because of notes attached to the victims' car windows indicating the presence of toxic gas. Autopsy findings included discoloration of lividity and an accentuation of the gray matter of the brain. Toxicology testing confirmed H2S exposure with the demonstration of high levels of thiosulfate in blood.In summary, suicide with H2S appears to be increasing in the United States.

  13. The chemical forms of mercury in aged and fresh dental amalgam surfaces.

    Science.gov (United States)

    George, Graham N; Singh, Satya P; Hoover, Jay; Pickering, Ingrid J

    2009-11-01

    Mercury-containing dental amalgam is known to be a source of human exposure to mercury. We have explored the use of electron yield Hg L(III) X-ray absorption spectroscopy to characterize the chemical nature of dental amalgam surfaces. We find that the method is practical and that it shows extensive mercury depletion in the surface of the aged amalgam with significant differences between old and fresh amalgam surfaces. Whereas the fresh amalgam gives spectra that are typical of metallic mercury, the aged amalgam is predominantly beta-mercuric sulfide. The toxicological implications of these results are discussed.

  14. Regenerative process for removal of mercury and other heavy metals from gases containing H.sub.2 and/or CO

    Science.gov (United States)

    Jadhav, Raja A [Naperville, IL

    2009-07-07

    A method for removal of mercury from a gaseous stream containing the mercury, hydrogen and/or CO, and hydrogen sulfide and/or carbonyl sulfide in which a dispersed Cu-containing sorbent is contacted with the gaseous stream at a temperature in the range of about 25.degree. C. to about 300.degree. C. until the sorbent is spent. The spent sorbent is contacted with a desorbing gaseous stream at a temperature equal to or higher than the temperature at which the mercury adsorption is carried out, producing a regenerated sorbent and an exhaust gas comprising released mercury. The released mercury in the exhaust gas is captured using a high-capacity sorbent, such as sulfur-impregnated activated carbon, at a temperature less than about 100.degree. C. The regenerated sorbent may then be used to capture additional mercury from the mercury-containing gaseous stream.

  15. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Dezhao, Liu; Hansen, Michael Jørgen

    oxidizing bacteria but several fungal families including Trichocomaceae. A positive correlation was found between the presence of mold and sulfide uptake. However there have been no reports on fungi metabolizing hydrogen sulfide. We hypothesize that the mold increases the air exposed surface, enabling...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  16. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Liu, Dezhao; Hansen, Michael Jørgen

    2012-01-01

    oxidizing bacteria but several fungal families including Trichocomaceae. A positive correlation was found between the presence of mold and sulfide uptake. However there have been no reports on fungi metabolizing hydrogen sulfide. We hypothesize that the mold increases the air exposed surface, enabling...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  17. STABILIZATION OF A MIXED WASTE SLUDGE SURROGATE CONTAINING MORE THAN 260 PPM MERCURY

    International Nuclear Information System (INIS)

    Smith, W. J.; Feizollahi, F.; Brimley, R.

    2002-01-01

    In an earlier demonstration of an innovative mercury stabilization technology for the Department of Energy, ATG's full-scale process stabilized mercury in soils that initially contained more than 260 ppm of mercury of unknown speciation. The treated waste satisfied the leaching standards for mercury that qualify wastes containing less than 260 ppm for land disposal. This paper describes the extension of that work to demonstrate a full-scale process for the stabilization of a representative sludge that contained more than 260 ppm of Hg of several mercury species. RCRA (Resource Conservation and Recovery Act) regulations now require the recovery of mercury from any waste containing more than 260 ppm of mercury, usually with thermal retorts. The results of this work with a surrogate sludge, and of the previous work with an actual soil, support a proposal now before the U.S. EPA (Environmental Protection Agency) to allow such wastes to be stabilized without retorting. The full-scale demonstration with a sulfide reagent reduced the mercury concentrations in extracts of treated sludge below the relevant leaching standard, a Universal Treatment Standard (UTS) limit of 0.025 mg mercury per liter of leachate generated by the Toxicity Characteristic Leaching Procedure (TCLP). The sulfide formulation reduced the concentration to about onehalf the UTS limit

  18. The Role of Dissolved Organic Matter in Environmental Mercury Methylation by Sulfate- Reducing Bacteria

    Science.gov (United States)

    Moreau, J. W.; Roden, E. E.; Gerbig, C.; Kim, C. S.; Aiken, G. R.; Dewild, J. F.; Krabbenhoft, D. P.

    2007-12-01

    Methylmercury (MeHg) production in the environment is controlled by many factors, including biogeochemical controls on mercury bioavailability. Strong focus has been placed on the role of sulfide concentration in determining mercury speciation and cellular uptake. However, in natural waters, dissolved organic matter (DOM) is both ubiquitous and important in influencing mercury speciation and bioavailability. We revisit this issue with experimental results from methylation assays of sulfate-reducing bacteria with a pure culture, and through synchrotron-based characterization of mercury in simulated natural waters. Pure cultures of Desulfobulbus propionicus, a sulfate-reducing bacterium (SRB) capable of fermentative growth, were allowed to methylate a mercury isotopic tracer present at growth conditions allowed control over ambient sulfide concentrations to favor the predicted dominance of dissolved HgS0. The DOM used was a hydrophobic fraction isolated from Florida Everglades surface water. Results showed that 5-10% of the mercury isotopic tracer was methylated in both DOM-amended and DOM-free cultures. In DOM-amended cultures, 10-20% greater cell growth was observed, suggesting an apparent slower rate of methylation in DOM-free cultures and a beneficial contribution of DOM to cell growth. We note that as much as ~10% of ambient mercury associated with DOM was also methylated, possibly explaining the observed difference in methylation rates in terms of dilution of the total bioavailable mercury pool for DOM-amended cultures. Our observations suggest that, in some cases, DOM- partitioned mercury is subject to microbial methylation at environmentally significant rates. The nature of mercury- sulfide-DOM interaction was investigated in separate experiments. No precipitation was observed in solutions containing DOM and equimolar Hg2+ and aqueous sulfide at concentrations supersaturated with respect to metacinnabar. The equilibrated Hg-S-DOM solution was loaded on

  19. Mercury removal in utility wet scrubber using a chelating agent

    Science.gov (United States)

    Amrhein, Gerald T.

    2001-01-01

    A method for capturing and reducing the mercury content of an industrial flue gas such as that produced in the combustion of a fossil fuel or solid waste adds a chelating agent, such as ethylenediaminetetraacetic acid (EDTA) or other similar compounds like HEDTA, DTPA and/or NTA, to the flue gas being scrubbed in a wet scrubber used in the industrial process. The chelating agent prevents the reduction of oxidized mercury to elemental mercury, thereby increasing the mercury removal efficiency of the wet scrubber. Exemplary tests on inlet and outlet mercury concentration in an industrial flue gas were performed without and with EDTA addition. Without EDTA, mercury removal totaled 42%. With EDTA, mercury removal increased to 71%. The invention may be readily adapted to known wet scrubber systems and it specifically provides for the removal of unwanted mercury both by supplying S.sup.2- ions to convert Hg.sup.2+ ions into mercuric sulfide (HgS) and by supplying a chelating agent to sequester other ions, including but not limited to Fe.sup.2+ ions, which could otherwise induce the unwanted reduction of Hg.sup.2+ to the form, Hg.sup.0.

  20. Environmental mercury problem

    Energy Technology Data Exchange (ETDEWEB)

    D' Itri, F.M.

    1972-01-01

    The urgent need to eliminate or greatly reduce the discharge of mercury into the environment is paramount to the health and well being of man. That all forms of mercury are hazardous is widely recognized, but what is more devastating to our society is that all forms of mercury appear to have the potential to be converted in to highly toxic monomethylmercury, or dimethylmercury. This paper examined the historical uses of mercury, the background concentrations of mercury, the analytical methods for the determination of mercury, the contamination of the food chain by mercury, the biological methylation of mercury, the decontamination and restoration of mercury polluted areas, the epidemiology and toxicology of mercury, and the chronology of the world's mercury poisoning problem.

  1. Decommissioning and safety issues of liquid-mercury waste generated from high power spallation sources with particle accelerators

    CERN Document Server

    Chiriki, S; Odoj, R; Moormann, R; Hinssen, H. K; Bukaemskiy, A

    2009-01-01

    Large spallation sources are intended to be constructed in Europe (EURISOL nuclear physics facility and ESS-European Spallation Source). These facilities accumulate more than 20 metric tons of irradiated mercury in the target, which has to be treated as highly radioactive and chemo-toxic waste. Because solids are the only appropriate (immobile) form for this radiotoxic and toxic type of waste solidification is required for irradiated mercury. Our irradiation experimental studies on mercury waste revealed that mercury sulfide is a reasonable solid for disposal and shows larger stability in assumed accidents with water ingress in a repository compared to amalgams. For preparation of mercury sulfide a wet process is more suitable than a dry one. It is easier to perform under hot cell conditions and allows complete Hg-conversion. Embedding HgS in a cementitious matrix increases its stability.

  2. Mining, metallurgy and the historical origin of mercury pollution in lakes and watercourses in Central Sweden.

    Science.gov (United States)

    Bindler, Richard; Yu, Ruilian; Hansson, Sophia; Classen, Neele; Karlsson, Jon

    2012-08-07

    In Central Sweden an estimated 80% of the lakes contain fish exceeding health guidelines for mercury. This area overlaps extensively with the Bergslagen ore region, where intensive mining of iron ores and massive sulfide ores occurred over the past millennium. Although only a few mines still operate today, thousands of mineral occurrences and mining sites are documented in the region. Here, we present data on long-term mercury pollution in 16 sediment records from 15 lakes, which indicate that direct release of mercury to lakes and watercourses was already significant prior to industrialization (mines. Although the timing and magnitude of the historical increases in mercury are heterogeneous among lakes, the data provide unambiguous evidence for an incidental release of mercury along with other mining metals to lakes and watercourses, which suggests that the present-day problem of elevated mercury concentrations in the Bergslagen region can trace its roots back to historical mining.

  3. Measurements of Mercury Released From Solidified/Stabilized Waste Forms-FY2002

    International Nuclear Information System (INIS)

    Mattus, C.H.

    2003-01-01

    This report covers work performed during FY 2002 in support of treatment demonstrations conducted for the U.S. Department of Energy (DOE) Mixed Waste Focus Area (MWFA) Mercury Working Group. To comply with the requirements of the Resource Conservation and Recovery Act, as implemented by the U.S. Environmental Protection Agency (EPA), DOE must use one of the following procedures for mixed low-level radioactive wastes containing mercury at levels above 260 ppm: a retorting/roasting treatment or (if the wastes also contain organics) an incineration treatment. The recovered radioactively contaminated mercury must then be treated by an amalgamation process prior to disposal. The DOE MWFA Mercury Working Group is working with EPA to determine whether some alternative processes could be used to treat these types of waste directly, thereby avoiding a costly recovery step for DOE. In previous years, demonstrations were performed in which commercial vendors applied their technologies for the treatment of radiologically contaminated elemental mercury as well as radiologically contaminated and mercury-contaminated waste soils from Brookhaven National Laboratory. The test results for mercury release in the headspace were reported in two reports, ''Measurements of Mercury Released from Amalgams and Sulfide Compounds'' (ORNL/TM-13728) and ''Measurements of Mercury Released from Solidified/Stabilized Waste Forms'' (ORNL/TM-2001/17). The current work did not use a real waste; a surrogate sludge had been prepared and used in the testing in an effort to understand the consequences of mercury speciation on mercury release

  4. Mercury Quick Facts: Health Effects of Mercury Exposure

    Science.gov (United States)

    Mercury Quick Facts Health Effects of Mercury Exposure What is Elemental Mercury? Elemental (metallic) mercury is the shiny, silver-gray metal found in thermometers, barometers, and thermostats and other ...

  5. Sulfur polymer cement stabilization of elemental mercury mixed waste

    International Nuclear Information System (INIS)

    Melamed, D.; Fuhrmann, M.; Kalb, P.; Patel, B.

    1998-04-01

    Elemental mercury, contaminated with radionuclides, is a problem throughout the Department of Energy (DOE) complex. This report describes the development and testing of a process to immobilize elemental mercury, contaminated with radionuclides, in a form that is non-dispersible, will meet EPA leaching criteria, and has low mercury vapor pressure. In this stabilization and solidification process (patent pending) elemental mercury is mixed with an excess of powdered sulfur polymer cement (SPC) and additives in a vessel and heated to ∼35 C, for several hours, until all of the mercury is converted into mercuric sulfide (HgS). Additional SPC is then added and the mixture raised to 135 C, resulting in a homogeneous molten liquid which is poured into a suitable mold where is cools and solidifies. The final stabilized and solidified waste forms were characterized by powder X-ray diffraction, as well as tested for leaching behavior and mercury vapor pressure. During this study the authors have processed the entire inventory of mixed mercury waste stored at Brookhaven National Laboratory (BNL)

  6. Sulfide intrusion and detoxification in Zostera marina

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    2014-01-01

    Sulfide intrusion in seagrasses represents a global threat to seagrasses. In contrast seegrasses grow in hostile sediments, where they are constantly exposed to sulfide intrusion. Little is known about the strategies to survive sulfide intrusion, if there are detoxification mechanisms and sulfur...... indicating a possible role of sulfide in the sulfur nutrition beside the detoxification function. Our results suggest different adaptations of Z. marina to reduced sediments and sulfide intrusion ranging from bacterial and chemical reoxidation of sulfide to sulfate to incorporation of sulfide into organic...

  7. Prevention of sulfide oxidation in sulfide-rich waste rock

    Science.gov (United States)

    Nyström, Elsa; Alakangas, Lena

    2015-04-01

    The ability to reduce sulfide oxidation in waste rock after mine closure is a widely researched area, but to reduce and/or inhibit the oxidation during operation is less common. Sulfide-rich (ca 30 % sulfur) waste rock, partially oxidized, was leached during unsaturated laboratory condition. Trace elements such as As and Sb were relatively high in the waste rock while other sulfide-associated elements such as Cu, Pb and Zn were low compared to common sulfide-rich waste rock. Leaching of unsaturated waste rock lowered the pH, from around six down to two, resulting in continuously increasing element concentrations during the leaching period of 272 days. The concentrations of As (65 mg/L), Cu (6.9 mg/L), Sb (1.2 mg/L), Zn (149 mg/L) and S (43 g/L) were strongly elevated at the end of the leaching period. Different alkaline industrial residues such as slag, lime kiln dust and cement kiln dust were added as solid or as liquid to the waste rock in an attempt to inhibit sulfide oxidation through neo-formed phases on sulfide surfaces in order to decrease the mobility of metals and metalloids over longer time scale. This will result in a lower cost and efforts of measures after mine closure. Results from the experiments will be presented.

  8. Apparatus for use in sulfide chemiluminescence detection

    Science.gov (United States)

    Spurlin, S.R.; Yeung, E.S.

    1987-01-06

    A method is described for chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction. 4 figs.

  9. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong

    2002-01-01

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min...... of milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  10. Mercury Methylation, Demethylation, and Bioavailability in the Hyporheic Sediments of a Northern Wisconsin Wetland

    Science.gov (United States)

    Creswell, J. E.; Babiarz, C. L.; Shafer, M. M.; Roden, E. E.; Armstrong, D. E.

    2007-12-01

    It is generally accepted that wetland sediments have a high potential to produce methylmercury, yet the factors controlling the relevant chemical transformations are poorly understood. Previous studies suggest that sulfate- reducing bacteria play an important role in methylation, but iron-reducing bacteria may also participate in this process. Methylation rates are influenced by both the concentration of Hg(II) and its speciation, which affects its bioavailability. Net accumulation depends also on demethylation rates, rates which may be significant in these systems. The objective of this study is to gain a better understanding of the main factors controlling the bioavailability of inorganic mercury for the production of methylmercury in wetland hyporheic zones. Stable isotopes of mercury are being used to investigate potential methylation and demethylation rates in the hyporheic sediments of Allequash Creek, near Boulder Junction, WI. Other techniques that are being applied to examine the chemical and biological drivers of mercury methylation and bioavailability include tin-reducible mercury "titrations" to measure the concentration of strong mercury-binding ligands in porewater, 14C-acetate uptake assays to determine the activity of the native microbial consortia , ion exchange resin experiments to explore the role of dissolved organic carbon in mercury binding, and inhibition studies (e.g. molybdenum amendments) of sulfate-reducing bacteria to assess their role in producing methylmercury. Manipulations of environmental conditions in laboratory microcosms are used to determine the relative importance of physical factors, such as temperature, and biogeochemical factors, such as sulfate, sulfide, dissolved organic carbon (DOC), and iron levels, on the fate of mercury in hyporheic systems. Preliminary results show that while significant levels of inorganic mercury are present in the hyporheic groundwater, strong mercury-binding ligands in the wetland porewaters at a

  11. Mercury speciation in environmental solid samples using thermal release technique with atomic absorption detection

    Energy Technology Data Exchange (ETDEWEB)

    Shuvaeva, Olga V. [Institute of Inorganic Chemistry, Academician Lavrent' ev Prospect 3, 630090 Novosbirsk (Russian Federation)], E-mail: olga@che.nsk.su; Gustaytis, Maria A.; Anoshin, Gennadii N. [Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Koptyug Prospect 3, 630090 Novosibirsk (Russian Federation)

    2008-07-28

    A sensitive and very simple method for determination of mercury species in solid samples has been developed involving thermal release analysis in combination with atomic absorption (AAS) detection. The method allows determination of mercury(II) chloride, methylmercury and mercury sulfide at the level of 0.70, 0.35 and 0.20 ng with a reproducibility of the results of 14, 25 and 18%, respectively. The accuracy of the developed assay has been estimated using certified reference materials and by comparison of the results with those of an independent method. The method has been applied for Hg species determination in original samples of lake sediments and plankton.

  12. Minamata Convention on Mercury

    Science.gov (United States)

    On November 6, 2013 the United States signed the Minamata Convention on Mercury, a new multilateral environmental agreement that addresses specific human activities which are contributing to widespread mercury pollution

  13. Mercury in Your Environment

    Science.gov (United States)

    Basic information about mercury, how it gets in the air, how people are exposed to it and health effects associated with exposure; what EPA and other organizations are doing to limit exposures; what citizens should know to minimize exposures and to reduce mercury in the environment; and information about products that contain mercury.

  14. Intentional intravenous mercury injection

    African Journals Online (AJOL)

    Three forms of mercury exist: elemental, inorganic and organic, all of which may be toxic with clinical consequences, depending on the type of exposure. Elemental mercury poisoning usually occurs via vapour inhalation, as mercury is well absorbed through the lungs. The central nervous system is then the major site of ...

  15. Infrared spectroscopy of solid hydrogen sulfide and deuterium sulfide.

    Science.gov (United States)

    Fathe, Kristin; Holt, Jennifer S; Oxley, Susan P; Pursell, Christopher J

    2006-09-21

    The infrared spectra of solid hydrogen sulfide (H2S) and deuterium sulfide (D2S) were collected at very low temperatures. Vapor deposition of thin films at the lowest temperature of 10 K produced amorphous solids while deposition at 70 K yielded the crystalline phase III. Infrared interference fringe patterns produced by the films during deposition were used to determine the film thickness. Careful measurement of the integrated absorbance peaks, along with the film thickness, allowed determination of the integrated band intensities. This report represents the first complete presentation of the infrared spectra of the amorphous solids. Observations of peaks near 3.915 and 1.982 microm (ca. 2554 and 5045 cm(-1), respectively) may be helpful in the conclusive identification of solid hydrogen sulfide on the surface of Io, a moon of Jupiter.

  16. Mercury inclusion a waste processing; Suigin ganyu haikibutsu no shori

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-06-05

    BNL (Brookhaven National Laboratory) developed process (SPSS) which granularly stabilized the mercury contamination material including the radioactive material. In the SPSS Inc. method, the sulfur similarly is made to react on the mercury with the amalgamation, and mercury sulfide of low vapor pressure is formed at the low solubility. In the new process, in this amalgamation, the dispersion of the fine powder becomes a problem, and the pollutant mixes with 'the sulfur (95%)-dicyclopentadiene (5%) mixture', and it pours in melting post-container heated to 120 degrees C. The possible uniform composition lump fixes mercury and radioisotope as the result. 200 of the EPA standard in the product by the pilot study the 0.5-3ppb mercury which drastically fell below ppb was contained. In addition, BNL has planned the test operation in the commercial. In the future, the processing of a mercury inclusion waste in the radioactive waste disposal authorization facilities will become possible, if the actual/real process is established. (translated by NEDO)

  17. Oxidation process of cadmium sulfide

    International Nuclear Information System (INIS)

    Hashimoto, Koshiro; Toda, Yoshitomo; Sato, Takayori

    1977-01-01

    Complicated thermogravimetric curve was observed on oxidation process of cadmium sulfide precipitate in air. Phases of various oxidation stage were identified by X-ray diffraction method. Cadmium sulfide was first oxidized to cadmium oxide at 400 0 C, while the successive reaction with sulfur dioxide and oxygen gases gave rise to cadmium sulfate. The phases such as 2 CdS. CdSO 4 , Cd 3 SO 6 and β-CdSO 4 appeared during the oxidation process up to 1100 0 C, at which all the particles were converted into cadmium oxide at 1100 0 C. Cadmium sulfide kept in nitrogen gas above 700 0 C was directly converted into cadmium oxide when oxygen gas was introduced into the furnace. (auth.)

  18. Mercury from combustion sources: a review of the chemical species emitted and their transport in the atmosphere

    International Nuclear Information System (INIS)

    Carpi, A.

    1997-01-01

    Different species of mercury have different physical/chemical properties and thus behave quite differentially in air pollution control equipment and in the atmosphere. In general, emission of mercury from coal combustion sources are approximately 20-50% elemental mercury (Hg 0 ) and 50-80% divalent mercury (Hg(II)), which may be predominantly HgCl 2 . Emissions of mercury from waste incinerators are approximately 10-20% Hg 0 and 75-85% Hg(II). The partitioning of mercury in flue gas between the elemental and divalent forms may be dependent on the concentration of particulate carbon, HCl and other pollutants in the stack emissions. The emission of mercury from combustion facilities depends on the species in the exhaust stream and the type of air pollution control equipment used at the source. Air pollution control equipment for mercury removal at combustion facilities includes activated carbon injection, sodium sulfide injection and wet lime/limestone flue gas desulfurization. White Hg(II) is water-soluble and may be removed form the atmosphere by wet and dry deposition close to the combustion sources, the combination of a high vapor pressure and low water-solubility facilitate the long-range transport of Hg 0 in the atmosphere. Background mercury in the atmosphere is predominantly Hg 0 . Elemental mercury is eventually removed from the atmosphere by dry deposition onto surfaces and by wet deposition after oxidation to water-soluble, divalent mercury. 62 refs., 2 figs., 1 tab

  19. Nanostructured metal sulfides for energy storage.

    Science.gov (United States)

    Rui, Xianhong; Tan, Huiteng; Yan, Qingyu

    2014-09-07

    Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

  20. 30 CFR 250.604 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.604 Section 250.604... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or in...

  1. 30 CFR 250.808 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.808 Section 250.808... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S...

  2. 30 CFR 250.504 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or in...

  3. Mercury evaporation from amalgams with varied mercury contents.

    Science.gov (United States)

    Ohmoto, K; Nakajima, H; Ferracane, J L; Shintani, H; Okabe, T

    2000-09-01

    This study examined the relationship between mercury content and mercury evaporation from amalgams during setting. Two different types of commercial high-copper amalgams (single composition and admixed types) were used. Cylindrical specimens of each amalgam were prepared with five different mercury contents according to ADA Specification No.1. Specimens were also prepared by hand condensation. Mercury evaporation from amalgam specimens maintained at 37 degrees C was measured using a gold film mercury analyzer from 10 min after the end of trituration until the mercury concentration in air reached an undetectable level. The mercury content more clearly influenced the mercury evaporation from the admixed type amalgam specimens when the mercury content decreased below the manufacturers' recommended trituration conditions. Triturating with less mercury than the manufacturers' recommended amount cannot lower the evaporation of mercury from freshly made amalgam. Proper condensing procedures can minimize the mercury evaporation from the amalgam surface.

  4. Mercury balance analysis

    International Nuclear Information System (INIS)

    Maag, J.; Lassen, C.; Hansen, E.

    1996-01-01

    A detailed assessment of the consumption of mercury, divided into use areas, was carried out. Disposal and emissions to the environment were also qualified. The assessment is mainly based on data from 1992 - 1993. The most important source of emission of mercury to air is solid waste incineration which is assessed in particular to be due to the supply of mercury in batteries (most likely mercury oxide batteries from photo equipment) and to dental fillings. The second most important source of mercury emission to air is coal-fired power plants which are estimated to account for 200-500 kg of mercury emission p.a. Other mercury emissions are mainly related to waste treatment and disposal. The consumption of mercury is generally decreasing. During the period from 1982/83 - 1992-93, the total consumption of mercury in Denmark was about halved. This development is related to the fact that consumption with regard to several important use areas (batteries, dental fillings, thermometers etc.) has been significantly reduced, while for other purposes the use of mercury has completely, or almost disappeared, i.e. (fungicides for seed, tubes etc.). (EG)

  5. Sulfide intrusion and detoxification in seagrasses ecosystems

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    is known about the strategies of seagrasses to survive sulfide intrusion, their potential detoxification mechanisms and sulfur nutrition in general. By a global review of sulfide intrusion, coupled with a series of field studies and in situ experiments we elucidate sulfide intrusion and different...... not present in terrestrial plants at that level. Sulfide is not necessarily toxic but used as sulfur nutrition, presupposing healthy seagrass ecosystems that can support detoxification mechanisms. Presence or absence of those mechanisms determines susceptibility of seagrass ecosystems to sediment sulfide...

  6. Process for low mercury coal

    Science.gov (United States)

    Merriam, Norman W.; Grimes, R. William; Tweed, Robert E.

    1995-01-01

    A process for producing low mercury coal during precombustion procedures by releasing mercury through discriminating mild heating that minimizes other burdensome constituents. Said mercury is recovered from the overhead gases by selective removal.

  7. Sulfide Melts and Chalcophile Element Behavior in High Temperature Systems

    Science.gov (United States)

    Wood, B. J.; Kiseeva, K.

    2016-12-01

    We recently found that partition coefficients (Di) of many weakly and moderately chalcophile elements (e.g., Cd, Zn, Co, Cr, Pb, Sb, In) between sulfide and silicate melts are simple functions of the FeO content of the silicate liquid: logDi A-Blog[FeO] where [FeO] is the FeO concentration in the silicate, A and B are constants and the latter is related to the valency of the element of interest. In contrast, some strongly chalcophile (e.g Cu, Ni, Ag) and lithophile elements (e.g Mn) show marked deviations from linearity on a plot of logDi vs log[FeO]. More recent experiments show that linear behavior is confined to elements whose affinities for S and O are similar to those of Fe. In the case of elements more strongly lithophile than Fe (Ti, U, REE, Zr, Nb, Ta, Mn) a plot of logDi versus log[FeO] describes a U-shape with the element partitioning strongly into the sulfide at very low FeO and again at very high FeO content of the silicate melt. In contrast, strongly chalcophile elements (Cu, Ni, Ag) describe an n-shape on the plot of logD vs log[FeO]. The result is that lithophile elements such as Nb become more "chalcophile" than Cu at very low and very high FeO contents of the silicate melt. The reasons for this surprising behavior are firstly that, at very low FeO contents the silicate melt dissolves substantial amounts of sulfur, which drives down the activity of FeO and, from mass-action "pulls" the lihophile element into the sulfide. At high FeO contents of the silicate the sulfide itself starts to dissolve substantial amounts of oxygen and lithophile elements follow the oxygen into the sulfide. Given the principles which we have established, we are able to describe the patterns of chalcophile element behavior during partial melting and fractional crystallisation on Earth and also on bodies such as Mercury and Mars which are, respectively, strongly reduced relative to Earth and more oxidised than Earth.

  8. Inhibition of Sulfide Mineral Oxidation by Surface Coating Agents: Batch

    Science.gov (United States)

    Choi, J.; Ji, M. K.; Yun, H. S.; Park, Y. T.; Gee, E. D.; Lee, W. R.; Jeon, B.-H.

    2012-04-01

    Mining activities and mineral industries have impacted on rapid oxidation of sulfide minerals such as pyrite (FeS2) which leads to Acid Mine Drainage (AMD) formation. Some of the abandoned mines discharge polluted water without proper environmental remediation treatments, largely because of financial constraints in treating AMD. Magnitude of the problem is considerable, especially in countries with a long history of mining. As metal sulfides become oxidized during mining activities, the aqueous environment becomes acid and rich in many metals, including iron, lead, mercury, arsenic and many others. The toxic heavy metals are responsible for the environmental deterioration of stream, groundwater and soils. Several strategies to remediate AMD contaminated sites have been proposed. Among the source inhibition and prevention technologies, microencapsulation (coating) has been considered as a promising technology. The encapsulation is based on inhibition of O2 diffusion by surface coating agent and is expected to control the oxidation of pyrite for a long time. Potential of several surface coating agents for preventing oxidation of metal sulfide minerals from both Young-Dong coal mine and Il-Gwang gold mine were examined by conducting batch experiments and field tests. Powdered pyrite as a standard sulfide mineral and rock samples from two mine outcrops were mixed with six coating agents (KH2PO4, MgO and KMnO4 as chemical agents, and apatite, cement and manganite as mineral agents) and incubated with oxidizing agents (H2O2 or NaClO). Batch experiments with Young-Dong coal mine samples showed least SO42- production in presence of KMnO4 (16% sulfate production compared to no surface coating agents) or cement (4%) within 8 days. In the case of Il-Gwang mine samples, least SO42- production was observed in presence of KH2PO4 (8%) or cement (2%) within 8 days. Field-scale pilot tests at Il-Gwang site also showed that addition of KH2PO4 decreased sulfate production from 200 to

  9. Speciation of mercury in soil and sediment by selective solvent and acid extraction

    Energy Technology Data Exchange (ETDEWEB)

    Han, Y. [Metara Inc., 1225 East Arques Ave, Sunnyvale, CA (United States); Kingston, H.M.; Boylan, H.M.; Rahman, G.M.M.; Shah, S.; Richter, R.C.; Link, D.D.; Bhandari, S. [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA (United States)

    2003-02-01

    In order to characterize the mercury hazard in soil, a sequential extraction scheme has been developed to classify mercury species based on their environmental mobility and/or toxicity for either routine lab analysis or on-site screening purposes. The alkyl mercury species and soluble inorganic species that contribute to the major portion of potential mercury toxicity in the soil are extracted by an acidic ethanol solution (2% HCl+10% ethanol solution) from soil matrices as ''mobile and toxic'' species. A High-Performance Liquid Chromatography (HPLC) system coupled with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) detection has been developed to further resolve the species information into soluble inorganic species (Hg{sup 2+}), methylmercury(II) (MeHg{sup +}) and ethylmercury(II) (EtHg{sup +}) species. Alternatively, these species can be separated into ''soluble inorganic mercury'' and ''alkyl mercury'' sub-categories by Solid-Phase Extraction (SPE). A custom Sulfydryl Cotton Fiber (SCF) material is used as the solid phase medium. Optimization of the SCF SPE technique is discussed. Combined with a direct mercury analyzer (DMA-80), the SCF SPE technique is a promising candidate for on-site screening purposes. Following the ethanol extraction, the inorganic mercury species remaining in soil are further divided into ''semi-mobile'' and ''non-mobile'' sub-categories by sequential acid extractions. The ''semi-mobile'' mercury species include mainly elemental mercury (Hg) and mercury-metal amalgams. The non-mobile mercury species mainly include mercuric sulfide (HgS) and mercurous chloride (Hg{sub 2}Cl{sub 2}). (orig.)

  10. Mercury is Moon's brother

    International Nuclear Information System (INIS)

    Ksanfomalifi, L.V.

    1976-01-01

    The latest information on Mercury planet is presented obtained by studying the planet with the aid of radar and space vehicles. Rotation of Mercury about its axis has been discovered; within 2/3 of its year it executes a complete revolution about its axis. In images obtained by the ''Mariner-10'' Mercurys surface differs little from that of the Moon. The ''Mariner-10'' has also discovered the Mercurys atmosphere, which consists of extremely rarefied helium. The helium is continuously supplied to the planet by the solar wind. The Mercury's magnetic field has been discovered, whose strength is 35 x 10 -4 at the Equator and 70 x 10 -4 E at the poles. The inclination of the dipole axis to the Mercury's rotation axis is 7 deg

  11. Peru Mercury Inventory 2006

    Science.gov (United States)

    Brooks, William E.; Sandoval, Esteban; Yepez, Miguel A.; Howard, Howell

    2007-01-01

    In 2004, a specific need for data on mercury use in South America was indicated by the United Nations Environmental Programme-Chemicals (UNEP-Chemicals) at a workshop on regional mercury pollution that took place in Buenos Aires, Argentina. Mercury has long been mined and used in South America for artisanal gold mining and imported for chlor-alkali production, dental amalgam, and other uses. The U.S. Geological Survey (USGS) provides information on domestic and international mercury production, trade, prices, sources, and recycling in its annual Minerals Yearbook mercury chapter. Therefore, in response to UNEP-Chemicals, the USGS, in collaboration with the Economic Section of the U.S. Embassy, Lima, has herein compiled data on Peru's exports, imports, and byproduct production of mercury. Peru was selected for this inventory because it has a 2000-year history of mercury production and use, and continues today as an important source of mercury for the global market, as a byproduct from its gold mines. Peru is a regional distributor of imported mercury and user of mercury for artisanal gold mining and chlor-alkali production. Peruvian customs data showed that 22 metric tons (t) of byproduct mercury was exported to the United States in 2006. Transshipped mercury was exported to Brazil (1 t), Colombia (1 t), and Guyana (1 t). Mercury was imported from the United States (54 t), Spain (19 t), and Kyrgyzstan (8 t) in 2006 and was used for artisanal gold mining, chlor-alkali production, dental amalgam, or transshipment to other countries in the region. Site visits and interviews provided information on the use and disposition of mercury for artisanal gold mining and other uses. Peru also imports mercury-containing batteries, electronics and computers, fluorescent lamps, and thermometers. In 2006, Peru imported approximately 1,900 t of a wide variety of fluorescent lamps; however, the mercury contained in these lamps, a minimum of approximately 76 kilograms (kg), and in

  12. Enhanced dissolution of cinnabar (mercuric sulfide) by dissolved organic matter isolated from the Florida Everglades

    Energy Technology Data Exchange (ETDEWEB)

    Ravichandran, M.; Ryan, J.N. [Univ. of Colorado, Boulder, CO (United States). Dept. of Civil, Environmental, and Architectural Engineering; Aiken, G.R.; Reddy, M.M. [Geological Survey, Boulder, CO (United States)

    1998-11-01

    Organic matter isolated from the Florida Everglades caused a dramatic increase in mercury release from cinnabar (HgS), a solid with limited solubility. Hydrophobic (a mixture of both humic and fulvic) acids dissolved more mercury than hydrophilic acids and other nonacid fractions of dissolved organic matter (DOM). Cinnabar dissolution by isolated organic matter and natural water samples was inhibited by cations such as Ca{sup 2+}. Dissolution was independent of oxygen content in experimental solutions. Dissolution experiments conducted in Dl water had no detectable dissolved mercury. The presence of various inorganic (chloride, sulfate, or sulfide) and organic ligands (salicylic acid, acetic acid, EDTA, or cysteine) did not enhance the dissolution of mercury from the mineral. Aromatic carbon content in the isolates correlated positively with enhanced cinnabar dissolution. {zeta}-potential measurements indicated sorption of negatively charged organic matter to the negatively charged cinnabar at pH 6.0. Possible mechanisms of dissolution include surface complexation of mercury and oxidation of surface sulfur species by the organic matter.

  13. Gravity Field and Internal Structure of Mercury from MESSENGER

    Science.gov (United States)

    Smith, David E.; Zuber, Maria T.; Phillips, Roger J.; Solomon, Sean C.; Hauck, Steven A., II; Lemoine, Frank G.; Mazarico, Erwan; Neumann, Gregory A.; Peale, Stanton J.; Margot, Jean-Luc; hide

    2012-01-01

    Radio tracking of the MESSENGER spacecraft has provided a model of Mercury's gravity field. In the northern hemisphere, several large gravity anomalies, including candidate mass concentrations (mascons), exceed 100 milli-Galileos (mgal). Mercury's northern hemisphere crust is thicker at low latitudes and thinner in the polar region and shows evidence for thinning beneath some impact basins. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/M(R(exp 2) = 0.353 +/- 0.017, where M and R are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of C(sub m)/C = 0.452 +/- 0.035. A model for Mercury s radial density distribution consistent with these results includes a solid silicate crust and mantle overlying a solid iron-sulfide layer and an iron-rich liquid outer core and perhaps a solid inner core.

  14. Modeling Mercury in Proteins

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jeremy C [ORNL; Parks, Jerry M [ORNL

    2016-01-01

    Mercury (Hg) is a naturally occurring element that is released into the biosphere both by natural processes and anthropogenic activities. Although its reduced, elemental form Hg(0) is relatively non-toxic, other forms such as Hg2+ and, in particular, its methylated form, methylmercury, are toxic, with deleterious effects on both ecosystems and humans. Microorganisms play important roles in the transformation of mercury in the environment. Inorganic Hg2+ can be methylated by certain bacteria and archaea to form methylmercury. Conversely, bacteria also demethylate methylmercury and reduce Hg2+ to relatively inert Hg(0). Transformations and toxicity occur as a result of mercury interacting with various proteins. Clearly, then, understanding the toxic effects of mercury and its cycling in the environment requires characterization of these interactions. Computational approaches are ideally suited to studies of mercury in proteins because they can provide a detailed picture and circumvent issues associated with toxicity. Here we describe computational methods for investigating and characterizing how mercury binds to proteins, how inter- and intra-protein transfer of mercury is orchestrated in biological systems, and how chemical reactions in proteins transform the metal. We describe quantum chemical analyses of aqueous Hg(II), which reveal critical factors that determine ligand binding propensities. We then provide a perspective on how we used chemical reasoning to discover how microorganisms methylate mercury. We also highlight our combined computational and experimental studies of the proteins and enzymes of the mer operon, a suite of genes that confers mercury resistance in many bacteria. Lastly, we place work on mercury in proteins in the context of what is needed for a comprehensive multi-scale model of environmental mercury cycling.

  15. Intentional intravenous mercury injection

    African Journals Online (AJOL)

    In this case report, intravenous complications, treatment strategies and possible ... Mercury toxicity is commonly associated with vapour inhalation or oral ingestion, for which there exist definite treatment options. Intravenous mercury ... personality, anxiousness, irritability, insomnia, depression and drowsi- ness.[1] However ...

  16. International mercury conference

    CSIR Research Space (South Africa)

    Leaner, J

    2006-10-01

    Full Text Available Mercury (Hg) affects human health and the environment, it calls for immediate action. Action is needed at local, regional and international level to reduce the risk associated with mercury, which is a global international problem, as it is a...

  17. Mercury's shifting, rolling past

    OpenAIRE

    Trulove, Susan

    2008-01-01

    Patterns of scalloped-edged cliffs or lobate scarps on Mercury's surface are thrust faults that are consistent with the planet shrinking and cooling with time. However, compression occurred in the planet's early history and Mariner 10 images revealed decades ago that lobate scarps are among the youngest features on Mercury. Why don't we find more evidence of older compressive features?

  18. MESSENGER: Exploring Mercury's Magnetosphere

    Science.gov (United States)

    Slavin, James A.

    2008-01-01

    The MESSENGER mission to Mercury offers our first opportunity to explore this planet's miniature magnetosphere since Mariner 10's brief fly-bys in 1974-5. Mercury's magnetosphere is unique in many respects. The magnetosphere of Mercury is the smallest in the solar system with its magnetic field typically standing off the solar wind only - 1000 to 2000 km above the surface. For this reason there are no closed dri-fi paths for energetic particles and, hence, no radiation belts; the characteristic time scales for wave propagation and convective transport are short possibly coupling kinetic and fluid modes; magnetic reconnection at the dayside magnetopause may erode the subsolar magnetosphere allowing solar wind ions to directly impact the dayside regolith; inductive currents in Mercury's interior should act to modify the solar In addition, Mercury's magnetosphere is the only one with its defining magnetic flux tubes rooted in a planetary regolith as opposed to an atmosphere with a conductive ionosphere. This lack of an ionosphere is thought to be the underlying reason for the brevity of the very intense, but short lived, approx. 1-2 min, substorm-like energetic particle events observed by Mariner 10 in Mercury's magnetic tail. In this seminar, we review what we think we know about Mercury's magnetosphere and describe the MESSENGER science team's strategy for obtaining answers to the outstanding science questions surrounding the interaction of the solar wind with Mercury and its small, but dynamic magnetosphere.

  19. Global Mercury Assessment 2013

    International Development Research Centre (IDRC) Digital Library (Canada)

    mercury pollution. This summary report and the accompanying. Technical Background Report for the Global. Mercury Assessment 2013 are developed in response to Decision 25/5, paragraph ... The use of different pollution control technologies in different ...... vegetation, snow, freshwater, and seawater. One of the largest ...

  20. Measurements of Mercury Released From Solidified/Stabilized Waste Forms-FY2002

    Energy Technology Data Exchange (ETDEWEB)

    Mattus, C.H.

    2003-02-17

    This report covers work performed during FY 2002 in support of treatment demonstrations conducted for the U.S. Department of Energy (DOE) Mixed Waste Focus Area (MWFA) Mercury Working Group. To comply with the requirements of the Resource Conservation and Recovery Act, as implemented by the U.S. Environmental Protection Agency (EPA), DOE must use one of the following procedures for mixed low-level radioactive wastes containing mercury at levels above 260 ppm: a retorting/roasting treatment or (if the wastes also contain organics) an incineration treatment. The recovered radioactively contaminated mercury must then be treated by an amalgamation process prior to disposal. The DOE MWFA Mercury Working Group is working with EPA to determine whether some alternative processes could be used to treat these types of waste directly, thereby avoiding a costly recovery step for DOE. In previous years, demonstrations were performed in which commercial vendors applied their technologies for the treatment of radiologically contaminated elemental mercury as well as radiologically contaminated and mercury-contaminated waste soils from Brookhaven National Laboratory. The test results for mercury release in the headspace were reported in two reports, ''Measurements of Mercury Released from Amalgams and Sulfide Compounds'' (ORNL/TM-13728) and ''Measurements of Mercury Released from Solidified/Stabilized Waste Forms'' (ORNL/TM-2001/17). The current work did not use a real waste; a surrogate sludge had been prepared and used in the testing in an effort to understand the consequences of mercury speciation on mercury release.

  1. Municipal actions to reduce mercury

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-03-15

    This paper presented proper management practices for products containing mercury. The measures can help reduce mercury releases, occupational exposure and mercury spills, thereby preventing impacts on human health and the environment. Despite mercury's toxic nature, many common products that contain mercury are commercially available. These include thermostats, thermometers, fluorescent lamps, pressure measuring devices, electrical switches and relays, and dental amalgam. Mercury emissions are also associated with base metal smelting, waste incineration and coal-fired power generation. Mercury in the environment is a global issue, because it can travel in the atmosphere on wind currents. The actions taken by municipalities to address the issue include reducing or eliminating mercury releases from internal municipal operations and sources within the community. This document provided guidance on how to develop a Municipal Mercury Elimination Policy and Plan that will help reduce mercury releases. It presented information and case studies that will help municipalities manage mercury-containing products found in municipal buildings and street lighting. Information on sources of mercury from within the community was presented along with case studies that can help municipalities determine where community action is needed to reduce mercury releases. The 5 modules of this document were intended to help municipalities identify priorities, timelines and budget requirements for mercury initiatives. It was emphasized that municipalities that adopt a Municipal Mercury Elimination Policy and Plan formally commit to reducing and eliminating mercury from the environment. tabs., figs.

  2. Getting Mercury out of Schools.

    Science.gov (United States)

    1999

    This guide was prepared while working with many Massachusetts schools to remove items that contain mercury and to find suitable alternatives. It contains fact sheets on: mercury in science laboratories and classrooms, mercury in school buildings and maintenance areas, mercury in the medical office and in medical technology classrooms in vocational…

  3. Sulfidation behavior of Fe20Cr alloys

    International Nuclear Information System (INIS)

    Pillis, Marina Fuser

    2001-01-01

    Alloys for use in high temperature environments rely on the formation of an oxide layer for their protection. Normally, these protective oxides are Cr 2 O 3 , Al 2 O 3 and, some times, SiO 2 . Many industrial gaseous environments contain sulfur. Sulfides, formed in the presence of sulfur are thermodynamically less stable, have lower melting points and deviate much more stoichiometrically, compared to the corresponding oxides. The mechanism of sulfidation of various metals is as yet not clear, in spite of the concerted efforts during the last decade. To help address this situation, the sulfidation behavior of Fe20Cr has been studied as a function of compositional modifications and surface state of the alloy. The alloys Fe20Cr, Fe20Cr0.7Y, Fe20Cr5Al and Fe20Cr5Al0.6Y were prepared and three sets of sulfidation tests were carried out. In the first set, the alloys were sulfidized at 700 deg C and 800 deg C for 10h. In the second set, the alloys were pre-oxidized at 1000 deg C and then sulfidized at 800 deg C for up to 45h. In the third set of tests, the initial stages of sulfidation of the alloys was studied. All the tests were carried out in a thermobalance, in flowing H 2 /2%H 2 S, and the sulfidation behavior determined as mass change per unit area. Scanning electron microscopy coupled to energy dispersive spectroscopy and X-ray diffraction analysis were used to characterize the reaction products. The addition of Y and Al increased sulfidation resistance of Fe20Cr. The addition of Y altered the species that diffused predominantly during sulfide growth. It changed from predominant cationic diffusion to predominant anionic diffusion. The addition of Al caused an even greater increase in sulfidation resistance of Fe20Cr, with the parabolic rate constant decreasing by three orders of magnitude. Y addition to the FeCrAl alloy did not cause any appreciable alteration in sulfidation resistance. Pre-oxidation of the FeCrAl and FeCrAlY alloys resulted in an extended

  4. Mercury: Informing Remote Sensing through Petrology in the Absence of Samples from the Innermost Planet

    Science.gov (United States)

    McCoy, T. J.; Nittler, L. R.; Stockstill-Cahill, K.; Blewett, D. T.

    2012-12-01

    Remote sensing missions and petrologic studies are complementary methods of understanding airless planetary bodies. For bodies with both orbital missions and samples available for laboratory study, missions provide global chemical, mineralogical, and geologic data sets and context for samples, whereas samples often provide complementary petrogenetic histories in a chronological framework. In contrast, although the wealth of orbital data from MESSENGER is not complemented by samples from Mercury, petrologic and experimental studies remain essential to understanding the innermost planet. Prior to MESSENGER, most models centered on high-temperature events and formation under highly reducing conditions to explain Mercury's high metal to silicate ratio. These models predicted enrichment in refractory elements and depletion in volatile elements. The inference of formation at highly reducing conditions is supported by MESSENGER results. The low FeO concentration in the crust, implied low FeO contents of the mantle, apparent efficient partitioning of iron into the core, and evidence for Ca- and/or Mg-sulfides from X-Ray Spectrometer data are all consistent with reducing conditions. In contrast, the suggestion that Mercury is highly volatile-depleted has been refuted. Direct evidence for a relatively volatile-rich planet come from Na, K, and S abundances measured on the surface with MESSENGER's XRS and Gamma-Ray Spectrometer and the presence of neutral and ionized Na, K, and S species in the exosphere. Indirect evidence for volatile-rich compositions include the suggestion of volcanic vents with associated mantling pyroclastic deposits, hollows inferred to form by geologically recent volatile loss, and an inferred interior structure that includes a solid iron sulfide layer at the top of Mercury's fluid core. Petrologic and experimental studies of meteorites have played a key role in deciphering orbital data from MESSENGER. Partial melts from an enstatite chondrite

  5. Mercury and trace element contents of Donbas coals and associated mine water in the vicinity of Donetsk, Ukraine

    Science.gov (United States)

    Kolker, A.; Panov, B.S.; Panov, Y.B.; Landa, E.R.; Conko, K.M.; Korchemagin, V.A.; Shendrik, T.; McCord, J.D.

    2009-01-01

    Mercury-rich coals in the Donets Basin (Donbas region) of Ukraine were sampled in active underground mines to assess the levels of potentially harmful elements and the potential for dispersion of metals through use of this coal. For 29 samples representing c11 to m3 Carboniferous coals, mercury contents range from 0.02 to 3.5 ppm (whole-coal dry basis). Mercury is well correlated with pyritic sulfur (0.01 to 3.2 wt.%), with an r2 of 0.614 (one outlier excluded). Sulfides in these samples show enrichment of minor constituents in late-stage pyrite formed as a result of interaction of coal with hydrothermal fluids. Mine water sampled at depth and at surface collection points does not show enrichment of trace metals at harmful levels, indicating pyrite stability at subsurface conditions. Four samples of coal exposed in the defunct open-cast Nikitovka mercury mines in Gorlovka have extreme mercury contents of 12.8 to 25.5 ppm. This coal was formerly produced as a byproduct of extracting sandstone-hosted cinnabar ore. Access to these workings is unrestricted and small amounts of extreme mercury-rich coal are collected for domestic use, posing a limited human health hazard. More widespread hazards are posed by the abandoned Nikitovka mercury processing plant, the extensive mercury mine tailings, and mercury enrichment of soils extending into residential areas of Gorlovka.

  6. Mercury's Dynamic Magnetic Tail

    Science.gov (United States)

    Slavin, James A.

    2010-01-01

    The Mariner 10 and MESSENGER flybys of Mercury have revealed a magnetosphere that is likely the most responsive to upstream interplanetary conditions of any in the solar system. The source of the great dynamic variability observed during these brief passages is due to Mercury's proximity to the Sun and the inverse proportionality between reconnection rate and solar wind Alfven Mach number. However, this planet's lack of an ionosphere and its small physical dimensions also contribute to Mercury's very brief Dungey cycle, approx. 2 min, which governs the time scale for internal plasma circulation. Current observations and understanding of the structure and dynamics of Mercury's magnetotail are summarized and discussed. Special emphasis will be placed upon such questions as: 1) How much access does the solar wind have to this small magnetosphere as a function of upstream conditions? 2) What roles do heavy planetary ions play? 3) Do Earth-like substorms take place at Mercury? 4) How does Mercury's tail respond to extreme solar wind events such coronal mass ejections? Prospects for progress due to advances in the global magnetohydrodynamic and hybrid simulation modeling and the measurements to be taken by MESSENGER after it enters Mercury orbit on March 18, 2011 will be discussed.

  7. How mercury can be themostreduced terrestrial planet and still store iron in its mantle

    OpenAIRE

    MALAVERGNE, Valérie; CORDIER, Patrick; RIGHTER, Kevin; BRUNETE, Fabrice; ZANDA, Brigitte; ADDAD, Ahmed; SMITH, Thomas; BUREAU, Hélène; SURBLE, Suzy; RAEPSAET, Caroline; CHARON, Emeline; H.HEWINS, Roger

    2014-01-01

    Mercury is notorious as the most reduced planet with the highest metal/silicate ratio, yet paradoxically data from the MESSENGER spacecraft show that its iron-poor crust is high in sulfur (up to ∼6 wt%, ∼80× Earth crust abundance) present mainly as Ca-rich sulfides on its surface. These particularities are simply impossible on the other terrestrial planets. In order to understand the role played by sulfur during the formation of Mercury, we investigated the phase relationships in ...

  8. Comparing and assessing different measurement techniques for mercury in coal systhesis gas

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, D.P.; Richardson, C.F. [Radian Corporation, Austin, TX (United States)

    1995-11-01

    Three mercury measurement techniques were performed on synthesis gas streams before and after an amine-based sulfur removal system. The syngas was sampled using (1) gas impingers containing a nitric acid-hydrogen peroxide solution, (2) coconut-based charcoal sorbent, and (3) an on-line atomic absorption spectrophotometer equipped with a gold amalgamation trap and cold vapor cell. Various impinger solutions were applied upstream of the gold amalgamation trap to remove hydrogen sulfide and isolate oxidized and elemental species of mercury. The results from these three techniques are compared to provide an assessment of these measurement techniques in reducing gas atmospheres.

  9. Inorganic: the other mercury.

    Science.gov (United States)

    Risher, John F; De Rosa, Christopher T

    2007-11-01

    There is a broad array of mercury species to which humans may be exposed. While exposure to methylmercury through fish consumption is widely recognized, the public is less aware of the sources and potential toxicity of inorganic forms of mercury. Some oral and laboratory thermometers, barometers, small batteries, thermostats, gas pressure regulators, light switches, dental amalgam fillings, cosmetic products, medications, cultural/religious practices, and gold mining all represent potential sources of exposure to inorganic forms of mercury. The route of exposure, the extent of absorption, the pharmacokinetics, and the effects all vary with the specific form of mercury and the magnitude and duration of exposure. If exposure is suspected, a number of tissue analyses can be conducted to confirm exposure or to determine whether an exposure might reasonably be expected to be biologically significant. By contrast with determination of exposure to methylmercury, for which hair and blood are credible indicators, urine is the preferred biological medium for the determination of exposure to inorganic mercury, including elemental mercury, with blood normally being of value only if exposure is ongoing. Although treatments are available to help rid the body of mercury in cases of extreme exposure, prevention of exposure will make such treatments unnecessary. Knowing the sources of mercury and avoiding unnecessary exposure are the prudent ways of preventing mercury intoxication. When exposure occurs, it should be kept in mind that not all unwanted exposures will result in adverse health consequences. In all cases, elimination of the source of exposure should be the first priority of public health officials.

  10. Using Sulfate-Amended Sediment Slurry Batch Reactors to Evaluate Mercury Methylation

    International Nuclear Information System (INIS)

    Harmon, S.M.

    2003-01-01

    In the methylated form, mercury represents a concern to public health primarily through the consumption of contaminated fish tissue. Research conducted on the methylation of mercury strongly suggests the process is microbial in nature and facilitated principally by sulfate-reducing bacteria. This study addressed the potential for mercury methylation by varying sulfate treatments and wetland-based soil in microbial slurry reactors with available inorganic mercury. Under anoxic laboratory conditions conducive to growth of naturally occurring sulfate-reducing bacteria in the soil, it was possible to evaluate how various sulfate additions influenced the methylation of inorganic mercury added to overlying water. Treatments included sulfate amendments ranging FR-om 25 to 500 mg/L (0.26 to 5.2 mM) above the soil's natural sulfate level. This study also provided an assessment of mercury methylation relative to sulfate-reducing bacterial population growth and subsequent sulfide production. Mercury methylation in sulfate treatments did not exceed that of the non-amended control during a 35-day incubation. However, increases in methylmercury concentration were linked to bacterial growth and sulfate reduction. A time lag in methylation in the highest treatment correlated with an equivalent lag in bacterial growth

  11. Disposal strategy of proton irradiated mercury from high power spallation sources

    International Nuclear Information System (INIS)

    Chiriki, Suresh

    2010-01-01

    Large spallation sources are intended to be constructed in Europe (EURISOL: nuclear physics research facility and ESS: European Spallation Source). These facilities would accumulate more than 20 metric tons of irradiated mercury in the target, which has to be treated as highly radioactive and chemo-toxic waste. Liquid waste cannot be tolerated in European repositories. As part of this work on safety/decommissioning of high-power spallation sources, our investigations were focused mainly to study experimentally and theoretically the solidification of liquid mercury waste (selection of an adequate solid mercury form and of an immobilization matrix, chemical engineering process studies on solidification/stabilization and on encapsulating in a matrix). Based on experimental results and supported by literature Hg-chalcogens (HgS, HgSe) will be more stable in repositories than amalgams. Our irradiation experimental studies on mercury waste revealed that mercury sulfide is a reasonable solid for disposal and shows larger stability in possible accidents with water ingress in a repository. Additionally immobilization of mercury in a cement matrix and polysiloxane matrix were tested. HgS formation from liquid target mercury by a wet process is identified as a suitable formation procedure. These investigations reveal that an almost 99.9% elementary Hg conversion can be achieved and that wet process can be reasonably handled under hot cell conditions. (orig.)

  12. Disposal strategy of proton irradiated mercury from high power spallation sources

    Energy Technology Data Exchange (ETDEWEB)

    Chiriki, Suresh

    2010-07-01

    Large spallation sources are intended to be constructed in Europe (EURISOL: nuclear physics research facility and ESS: European Spallation Source). These facilities would accumulate more than 20 metric tons of irradiated mercury in the target, which has to be treated as highly radioactive and chemo-toxic waste. Liquid waste cannot be tolerated in European repositories. As part of this work on safety/decommissioning of high-power spallation sources, our investigations were focused mainly to study experimentally and theoretically the solidification of liquid mercury waste (selection of an adequate solid mercury form and of an immobilization matrix, chemical engineering process studies on solidification/stabilization and on encapsulating in a matrix). Based on experimental results and supported by literature Hg-chalcogens (HgS, HgSe) will be more stable in repositories than amalgams. Our irradiation experimental studies on mercury waste revealed that mercury sulfide is a reasonable solid for disposal and shows larger stability in possible accidents with water ingress in a repository. Additionally immobilization of mercury in a cement matrix and polysiloxane matrix were tested. HgS formation from liquid target mercury by a wet process is identified as a suitable formation procedure. These investigations reveal that an almost 99.9% elementary Hg conversion can be achieved and that wet process can be reasonably handled under hot cell conditions. (orig.)

  13. Methyl mercury production and loss in Arctic soil.

    Science.gov (United States)

    Oiffer, Lindsay; Siciliano, Steven D

    2009-02-15

    Mercury has been found in polar bears and other top predators in the Arctic at concentrations that pose a risk to the indigenous population, however, the means by which this occurs is uncertain. There has been extensive research on the atmospheric cycling of mercury but little is known about mercury cycling in Arctic terrestrial ecosystems. The objective of this study was to determine whether wet sedge meadow soils within the Truelove Lowlands, Devon Island, NT, Canada (75 degrees 33'N, 84 degrees 40'N) were acting as sources or sinks for methylmercury (MeHg). Over the course of an Arctic summer, MeHg concentrations and other biophysical characteristics were measured at four wet sedge meadows over a 19 day study period that commenced approximately 1 month after snowmelt. Soil MeHg concentrations declined during the study period, indicating a net loss of MeHg over the summer. The dominant ligand in solution appeared to be dissolved organic matter, little sulfide was detected, and it would seem that most of the mercury was unavailable for methylation during the summer sampling period. In soil microcosms, spiked with 5.0 nmol g(-1) (1 microg g(-1)) HgCl2, the soil did methylate mercury suggesting that there is the potential for mercury methylation. We also noted significant spatial variability in MeHg concentrations between catenas that could not be explained by other biophysical parameters, which are known to affect methylation. Given our data and previous geochemical data collected from suprapermafrost groundwater during snowmelt, it seems likely that methylation may occur during the spring melt period in the arctic. Furthermore the geochemical variability of the melt water may lead to the spatial variability observed in MeHg concentrations in this study.

  14. Recovery of mercury from mercury compounds via electrolytic methods

    Science.gov (United States)

    Grossman, Mark W.; George, William A.

    1988-01-01

    A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

  15. Sulfide toxicity kinetics of a uasb reactor

    Directory of Open Access Journals (Sweden)

    D. R. Paula Jr.

    2009-12-01

    Full Text Available The effect of sulfide toxicity on kinetic parameters of anaerobic organic matter removal in a UASB (up-flow anaerobic sludge blanket reactor is presented. Two lab-scale UASB reactors (10.5 L were operated continuously during 12 months. The reactors were fed with synthetic wastes prepared daily using glucose, ammonium acetate, methanol and nutrient solution. One of the reactors also received increasing concentrations of sodium sulfide. For both reactors, the flow rate of 16 L.d-1 was held constant throughout the experiment, corresponding to a hydraulic retention time of 15.6 hours. The classic model for non-competitive sulfide inhibition was applied to the experimental data for determining the overall kinetic parameter of specific substrate utilization (q and the sulfide inhibition coefficient (Ki. The application of the kinetic parameters determined allows prediction of methanogenesis inhibition and thus the adoption of operating parameters to minimize sulfide toxicity in UASB reactors.

  16. The tectonics of Mercury

    International Nuclear Information System (INIS)

    Melosh, H.J.; Mckinnon, W.B.

    1988-01-01

    The probable tectonic history of Mercury and the relative sequence of events are discussed on the basis of data collected by the Mariner-10 spacecraft. Results indicate that Mercury's tectonic activity was confined to its early history; its endogenic activity was principally due to a small change in the shape of its lithosphere, caused by tidal despinning, and a small change in area caused by shrinkage due to cooling. Exogenic processes, in particular the impact activity, have produced more abundant tectonic features. Many features associated with the Caloris basin are due to loading of Mercury's thick lithosphere by extrusive lavas or subsidence due to magma withdrawal. It is emphasized that tectonic features observed on Mercury yield insight into the earliest tectonic events on planets like Mars and, perhaps, the earth, where subsequent events obscured or erased the most ancient tectonic records

  17. Mercury CEM Calibration

    Energy Technology Data Exchange (ETDEWEB)

    John F. Schabron; Joseph F. Rovani; Susan S. Sorini

    2007-03-31

    The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005, requires that calibration of mercury continuous emissions monitors (CEMs) be performed with NIST-traceable standards. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor generators. The traceability protocol will be written by EPA. Traceability will be based on the actual analysis of the output of each calibration unit at several concentration levels ranging from about 2-40 ug/m{sup 3}, and this analysis will be directly traceable to analyses by NIST using isotope dilution inductively coupled plasma/mass spectrometry (ID ICP/MS) through a chain of analyses linking the calibration unit in the power plant to the NIST ID ICP/MS. Prior to this project, NIST did not provide a recommended mercury vapor pressure equation or list mercury vapor pressure in its vapor pressure database. The NIST Physical and Chemical Properties Division in Boulder, Colorado was subcontracted under this project to study the issue in detail and to recommend a mercury vapor pressure equation that the vendors of mercury vapor pressure calibration units can use to calculate the elemental mercury vapor concentration in an equilibrium chamber at a particular temperature. As part of this study, a preliminary evaluation of calibration units from five vendors was made. The work was performed by NIST in Gaithersburg, MD and Joe Rovani from WRI who traveled to NIST as a Visiting Scientist.

  18. Mercury in human hair

    International Nuclear Information System (INIS)

    Kapauan, P.A.; Cruz, C.C.; Verceluz, F.P.

    1980-10-01

    The analysis of mercury (Hg) in scalp hair obtained from individuals residing in five different localities in the Philippines - Metro Manila, Naga City in Bicol, Bataan, Oriental Mindoro, and Palawan is presented. An overall mean of 1.46 ug/g of hair was obtained for all samples excluding those from Palawan and represents a baseline value.'' In terms of the mercury levels found in hair, the Honda Bay area in Palawan is, relatively, a ''contaminated area.'' (author)

  19. In Vitro Studies Evaluating Leaching of Mercury from Mine Waste Calcine Using Simulated Human Body Fluids

    OpenAIRE

    Gray, John E.; Plumlee, Geoffrey S.; Morman, Suzette A.; Higueras, Pablo L.; Crock, James G.; Lowers, Heather A.; Witten, Mark L.

    2010-01-01

    In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almad?n, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute prim...

  20. Method and apparatus for monitoring mercury emissions

    Science.gov (United States)

    Durham, Michael D.; Schlager, Richard J.; Sappey, Andrew D.; Sagan, Francis J.; Marmaro, Roger W.; Wilson, Kevin G.

    1997-01-01

    A mercury monitoring device that continuously monitors the total mercury concentration in a gas. The device uses the same chamber for converting speciated mercury into elemental mercury and for measurement of the mercury in the chamber by radiation absorption techniques. The interior of the chamber is resistant to the absorption of speciated and elemental mercury at the operating temperature of the chamber.

  1. Mercury pollution in Malaysia.

    Science.gov (United States)

    Hajeb, Parvaneh; Jinap, S; Ismail, Ahmad; Mahyudin, Nor Ainy

    2012-01-01

    Although several studies have been published on levels of mercury contamination of the environment, and of food and human tissues in Peninsular Malaysia, there is a serious dearth of research that has been performed in East Malaysia (Sabah and Sarawak). Industry is rapidly developing in East Malaysia, and, hence, there is a need for establishing baseline levels of mercury contamination in environmental media in that part of the country by performing monitoring studies. Residues of total mercury and inorganic in food samples have been determined in nearly all previous studies that have been conducted; however, few researchers have analyzed samples for the presence of methlymercury residues. Because methylmercury is the most toxic form of mercury, and because there is a growing public awareness of the risk posed by methylmercury exposure that is associated with fish and seafood consumption, further monitoring studies on methylmercury in food are also essential. From the results of previous studies, it is obvious that the economic development in Malaysia, in recent years, has affected the aquatic environment of the country. Primary areas of environmental concern are centered on the rivers of the west Peninsular Malaysian coast, and the coastal waters of the Straits of Malacca, wherein industrial activities are rapidly expanding. The sources of existing mercury input to both of these areas of Malaysia should be studied and identified. Considering the high levels of mercury that now exists in human tissues, efforts should be continued, and accelerated in the future, if possible, to monitor mercury contamination levels in the coastal states, and particularly along the west Peninsular Malaysian coast. Most studies that have been carried out on mercury residues in environmental samples are dated, having been conducted 20-30 years ago; therefore, the need to collect much more and more current data is urgent. Furthermore, establishing baseline levels of mercury exposure to

  2. Fabrication of mercury target vessel

    International Nuclear Information System (INIS)

    Wakui, Takashi; Kogawa, Hiroyuki; Haga, Katsuhiro; Futakawa, Masatoshi; Hayashi, Ryoichi; Uchiyama, Naoyoshi; Okamoto, Yoshinao; Nakamura, Koji

    2010-03-01

    The construction of materials and life science experimental facility in J-PARC (Japan Proton Accelerator Complex) project had been completed and accepted pulsed proton beams with low power. Since 2003, the detailed design, fabrication and examination for the mercury target vessel as a pulsed neutron source were carried out by the vender. The mercury target vessel consists of triple-walled structure in order to prevent the leak of mercury to outside at the failure of the mercury vessel and to remove the heat of the safety hull, which covers the mercury vessel, due to the injection of the pulsed proton beams. The high fabrication accuracy is required for the mercury target vessel assembled by the welding, because there are the relationships between the mercury target vessel and other components (target trolley, target storage container, flange of helium vessel, reflector and water-cooled shield). At each fabrication step, the examinations for the mercury target vessel with multi-walled structure were required. In this report, the required specification and basic structure of parts in the mercury target vessel are described and the fabrication procedure of the mercury target vessel by the vender is reported. In the fabrication of the mercury target vessel, there were many troubles such as large deformation due to the welding and then the vender repaired and brought the mercury target vessel to completion. Furthermore, improvements for the design and fabrication of the mercury target are reported. (author)

  3. Mercury isotope constraints on the source for sediment-hosted lead-zinc deposits in the Changdu area, southwestern China

    Science.gov (United States)

    Xu, Chunxia; Yin, Runsheng; Peng, Jiantang; Hurley, James P.; Lepak, Ryan F.; Gao, Jianfeng; Feng, Xinbin; Hu, Ruizhong; Bi, Xianwu

    2018-03-01

    The Lanuoma and Cuona sediment-hosted Pb-Zn deposits hosted by Upper Triassic limestone and sandstone, respectively, are located in the Changdu area, SW China. Mercury concentrations and Hg isotopic compositions from sulfide minerals and potential source rocks (e.g., the host sedimentary rocks and the metamorphic basement) were investigated to constrain metal sources and mineralization processes. In both deposits, sulfide minerals have higher mercury (Hg) concentrations (0.35 to 1185 ppm) than the metamorphic basement rocks (0.05 to 0.15 ppm) and sedimentary rocks (0.02 to 0.08 ppm). Large variations of mass-dependent fractionation (3.3‰ in δ202Hg) and mass-independent fractionation (0.3‰ in Δ199Hg) of Hg isotopes were observed. Sulfide minerals have Hg isotope signatures that are similar to the hydrothermal altered rocks around the deposit, and similar to the metamorphic basement, but different from barren sedimentary rocks. The variation of Δ199Hg suggests that Hg in sulfides was mainly derived from the underlying metamorphic basement. Mercury isotopes could be a geochemical tracer in understanding metal sources in hydrothermal ore deposits.

  4. Mercury Emissions: The Global Context

    Science.gov (United States)

    Mercury emissions are a global problem that knows no national or continental boundaries. Mercury that is emitted to the air can travel thousands of miles in the atmosphere before it is eventually deposited back to the earth.

  5. Mercury's magnetic field and interior

    International Nuclear Information System (INIS)

    Connerney, J.E.P.; Ness, N.F.

    1988-01-01

    The magnetic-field data collected on Mercury by the Mariner-10 spacecraft present substantial evidence for an intrinsic global magnetic field. However, studies of Mercury's thermal evolution show that it is most likely that the inner core region of Mercury solidified or froze early in the planet's history. Thus, the explanation of Mercury's magnetic field in the framework of the traditional planetary dynamo is less than certain

  6. Sulfide Intrusion and Detoxification in the Seagrass Zostera marina

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    2015-01-01

    Gaseous sulfide intrusion into seagrasses growing in sulfidic sediments causes little or no harm to the plant, indicating the presence of an unknown sulfide tolerance or detoxification mechanism. We assessed such mechanism in the seagrass Zostera marina in the laboratory and in the field...... as sulfate throughout the plant. We conclude that avoidance of sulfide exposure by reoxidation of sulfide in the rhizosphere or aerenchyma and tolerance of sulfide intrusion by incorporation of sulfur in the plant are likely major survival strategies of seagrasses in sulfidic sediments....

  7. Human and ecological remediation goals for soil mercury at East Fork Poplar Creek, Oak Ridge, TN

    International Nuclear Information System (INIS)

    Zafran, F.A.; Cornaby, B.W.; Hadden, C.T.

    1995-01-01

    Mercury, used in the past production of enriched lithium by the Department of Energy, is the principal chemical of concern in the 14-mile floodplain of East Fork Poplar Creek (EFPC). SAIC has developed risk-based remediation goal options (RGOS) for mercury in EFPC soils to protect the most sensitive human receptors. The existing chronic oral RfD for mercury is based on exposure of laboratory species to mercuric chloride. However, speciation and leaching/availability studies (conducted by EPA EMSL and Oak Ridge National Laboratory) indicated less soluble and less toxic mercury species, principally mercuric sulfide, with measurable quantities of metallic mercury also present, predominate in EFPC floodplain soils. SAIC derived human health RGOs using deterministic and probabilistic methods and incorporated the probability density function for bioavailability of mercury species from leaching/availability data generated by ORNL. Monte Carlo simulation was used in uncertainty analysis and supported the derivation of a protective, but realistic risk-based remediation goal of 400 mg mercury/kg soil. For ecological risk assessment, RGOs were based on risks through food chains from contaminants in soil. The authors describe a terrestrial food-chain model of contaminant transfer to primary producers, first-order consumers, mid-level predators, and top-level predators. The model uses published toxicity data, site-specific contaminant concentrations, and bioaccumulation factors calculated from measured body burdens of floodplain organisms to compute RGOs for various combinations of exposure parameters. Model calculations show that under reasonably conservative conditions, mid-level predators have the highest exposures relative to dietary limits and, therefore, require the lowest soil-mercury RGOs. Mercury concentrations of ∼500 mg/kg are protective of the receptor populations exposed through food chains at this site

  8. Reference Atmosphere for Mercury

    Science.gov (United States)

    Killen, Rosemary M.

    2002-01-01

    We propose that Ar-40 measured in the lunar atmosphere and that in Mercury's atmosphere is due to current diffusion into connected pore space within the crust. Higher temperatures at Mercury, along with more rapid loss from the atmosphere will lead to a smaller column abundance of argon at Mercury than at the Moon, given the same crustal abundance of potassium. Because the noble gas abundance in the Hermean atmosphere represents current effusion, it is a direct measure of the crustal potassium abundance. Ar-40 in the atmospheres of the planets is a measure of potassium abundance in the interiors, since Ar-40 is a product of radiogenic decay of K-40 by electron capture with the subsequent emission of a 1.46 eV gamma-ray. Although the Ar-40 in the Earth's atmosphere is expected to have accumulated since the late bombardment, Ar-40 in the atmospheres of Mercury and the Moon is eroded quickly by photoionization and electron impact ionization. Thus, the argon content in the exospheres of the Moon and Mercury is representative of current effusion rather than accumulation over the lifetime of the planet.

  9. Mercury in coal and the impact of coal quality on mercury emissions from combustion systems

    International Nuclear Information System (INIS)

    Kolker, Allan; Senior, Constance L.; Quick, Jeffrey C.

    2006-01-01

    The proportion of Hg in coal feedstock that is emitted by stack gases of utility power stations is a complex function of coal chemistry and properties, combustion conditions, and the positioning and type of air pollution control devices employed. Mercury in bituminous coal is found primarily within Fe-sulfides, whereas lower rank coal tends to have a greater proportion of organic-bound Hg. Preparation of bituminous coal to reduce S generally reduces input Hg relative to in-ground concentrations, but the amount of this reduction varies according to the fraction of Hg in sulfides and the efficiency of sulfide removal. The mode of occurrence of Hg in coal does not directly affect the speciation of Hg in the combustion flue gas. However, other constituents in the coal, notably Cl and S, and the combustion characteristics of the coal, influence the species of Hg that are formed in the flue gas and enter air pollution control devices. The formation of gaseous oxidized Hg or particulate-bound Hg occurs post-combustion; these forms of Hg can be in part captured in the air pollution control devices that exist on coal-fired boilers, without modification. For a given coal type, the capture efficiency of Hg by pollution control systems varies according to type of device and the conditions of its deployment. For bituminous coal, on average, more than 60% of Hg in flue gas is captured by fabric filter (FF) and flue-gas desulfurization (FGD) systems. Key variables affecting performance for Hg control include Cl and S content of the coal, the positioning (hot side vs. cold side) of the system, and the amount of unburned C in coal ash. Knowledge of coal quality parameters and their effect on the performance of air pollution control devices allows optimization of Hg capture co-benefit

  10. Mercury content of edible mushrooms

    Energy Technology Data Exchange (ETDEWEB)

    Woidich, H.; Pfannhauser, W.

    1975-05-01

    The mercury content of edible fungi is different. Relatively high burdened are Boletus and Agaricus campestris. A minimum of mercury is found in Russula, Agaricus bisporus and Cantharellus cibarius. The possibilities of mercury uptake and the potential cumulation mechanism is discussed. 8 references, 3 tables.

  11. Mercury (Environmental Health Student Portal)

    Science.gov (United States)

    ... Water Waterborne Diseases & Illnesses Water Cycle Water Treatment Mercury The Basics Mercury — sometimes called quicksilver — is a natural metal. It’s ... to breathe it in without knowing it. When mercury combines with other chemical elements, it creates compounds, ...

  12. Sensing Mercury for Biomedical and Environmental Monitoring

    Directory of Open Access Journals (Sweden)

    Julia Xiaojun Zhao

    2009-07-01

    Full Text Available Mercury is a very toxic element that is widely spread in the atmosphere, lithosphere, and surface water. Concentrated mercury poses serious problems to human health, as bioaccumulation of mercury within the brain and kidneys ultimately leads to neurological diseases. To control mercury pollution and reduce mercury damage to human health, sensitive determination of mercury is important. This article summarizes some current sensors for the determination of both abiotic and biotic mercury. A wide array of sensors for monitoring mercury is described, including biosensors and chemical sensors, while piezoelectric and microcantilever sensors are also described. Additionally, newly developed nanomaterials offer great potential for fabricating novel mercury sensors. Some of the functional fluorescent nanosensors for the determination of mercury are covered. Afterwards, the in vivo determination of mercury and the characterization of different forms of mercury are discussed. Finally, the future direction for mercury detection is outlined, suggesting that nanomaterials may provide revolutionary tools in biomedical and environmental monitoring of mercury.

  13. Electrochemical Synthesis and Characterization of Zinc Sulfide Nanoparticles

    OpenAIRE

    M. Rahimi-Nasarabadi

    2014-01-01

    Electrosynthesis process has been used for preparation of zinc sulfide nanoparticles. Zinc sulfide nanoparticles in different size and shapes were electrodeposited by electrolysis of zinc plate as anode in sodium sulfide solution. Effects of several reaction variables, such as electrolysis voltage, sulfide ion concentration as reactant, stirring rate of electrolyte solution and temperature on particle size of prepared zinc sulfide were investigated. The significance of these parameters in tun...

  14. Platinum Metals in Magmatic Sulfide Ores

    Science.gov (United States)

    Naldrett, A. J.; Duke, J. M.

    1980-06-01

    Platinum-group elements (PGE) are mined predominantly from deposits that have formed by the segregation of molten iron-nickel-copper sulfides from silicate magmas. The absolute concentrations of PGE in sulfides from different deposits vary over a range of five orders of magnitude, whereas those of other chalcophile elements vary by factors of only 2 to 100. However, the relative proportions of the different PGE in a given deposit are systematically related to the nature of the parent magma. The absolute and relative concentrations of PGE in magmatic sulfides are explained in terms of the degree of partial melting of mantle peridotite required to produce the parent magma and the processes of batch equilibration and fractional segregation of sulfides. The Republic of South Africa and the U.S.S.R. together possess more than 97 percent of the world PGE reserves, but significant undeveloped resources occur in North America. The Stillwater complex in Montana is perhaps the most important example.

  15. Crossett Hydrogen Sulfide Air Sampling Report

    Science.gov (United States)

    This report summarizes the results of the EPA’s hydrogen sulfide air monitoring conducted along Georgia Pacific’s wastewater treatment system and in surrounding Crossett, AR, neighborhoods in 2017.

  16. Chemical Forms of Mercury And Selenium in Fish Following Digestion With Simulated Gastric Fluid

    Energy Technology Data Exchange (ETDEWEB)

    George, G.N.; Singh, S.P.; Prince, R.C.; Pickering, I.J.

    2009-05-18

    Fish is a major dietary source of potentially neurotoxic methylmercury compounds for humans. It is also a rich source of essential selenium. We have used in situ mercury L{sub III}-edge and selenium K-edge X-ray absorption spectroscopy to chemically characterize the methylmercury and selenium in both fresh fish and fish digested with simulated gastric fluid. For the mercury, we confirm our earlier finding [Harris et al. (2003) Science301, 1203] that the methylmercury is coordinated by a single thiolate donor, which resembles cysteine, and for the selenium, we find a mixture of organic forms that resemble selenomethionine and an aliphatic selenenyl sulfide such as Cys-S-Se-Cys. We find that local chemical environments of mercury and selenium do not change upon digestion of the fish with simulated gastric fluid. We discuss the toxicological implications for humans consuming fish.

  17. Water displacement mercury pump

    Science.gov (United States)

    Nielsen, M.G.

    1984-04-20

    A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

  18. Mercury CEM Calibration

    Energy Technology Data Exchange (ETDEWEB)

    John Schabron; Joseph Rovani; Mark Sanderson

    2008-02-29

    Mercury continuous emissions monitoring systems (CEMS) are being implemented in over 800 coal-fired power plant stacks. The power industry desires to conduct at least a full year of monitoring before the formal monitoring and reporting requirement begins on January 1, 2009. It is important for the industry to have available reliable, turnkey equipment from CEM vendors. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor generators. The generators are used to calibrate mercury CEMs at power plant sites. The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005 requires that calibration be performed with NIST-traceable standards (Federal Register 2007). Traceability procedures will be defined by EPA. An initial draft traceability protocol was issued by EPA in May 2007 for comment. In August 2007, EPA issued an interim traceability protocol for elemental mercury generators (EPA 2007). The protocol is based on the actual analysis of the output of each calibration unit at several concentration levels ranging initially from about 2-40 {micro}g/m{sup 3} elemental mercury, and in the future down to 0.2 {micro}g/m{sup 3}, and this analysis will be directly traceable to analyses by NIST. The document is divided into two separate sections. The first deals with the qualification of generators by the vendors for use in mercury CEM calibration. The second describes the procedure that the vendors must use to certify the generator models that meet the qualification specifications. The NIST traceable certification is performance based, traceable to analysis using isotope dilution inductively coupled plasma/mass spectrometry performed by NIST in Gaithersburg, MD. The

  19. Sulfide as a soil phytotoxin - A review

    Directory of Open Access Journals (Sweden)

    Leon P M Lamers

    2013-07-01

    Full Text Available In wetland soils and underwater sediments of marine, brackish and freshwater systems, the strong phytotoxin sulfide may accumulate as a result of microbial reduction of sulfate during anaerobiosis, its level depending on prevailing edaphic conditions. In this review, we compare an extensive body of literature on phytotoxic effects of this reduced sulfur compound in different ecosystem types, and review the effects of sulfide at multiple ecosystem levels: the ecophysiological functioning of individual plants, plant-microbe associations, and community effects including competition and facilitation interactions. Recent publications on multi-species interactions in the rhizosphere show even more complex mechanisms explaining sulfide resistance. It is concluded that sulfide is a potent phytotoxin, profoundly affecting plant fitness and ecosystem functioning in the full range of wetland types including coastal systems, and at several levels. Traditional toxicity testing including hydroponic approaches generally neglect rhizospheric effects, which makes it difficult to extrapolate results to real ecosystem processes. To explain the differential effects of sulfide at the different organizational levels, profound knowledge about the biogeochemical, plant physiological and ecological rhizosphere processes is vital. This information is even more important, as anthropogenic inputs of sulfur into freshwater ecosystems and organic loads into freshwater and marine systems are still much higher than natural levels, and are steeply increasing in Asia. In addition, higher temperatures as a result of global climate change may lead to higher sulfide production rates in shallow waters.

  20. Air-water transfer of hydrogen sulfide

    DEFF Research Database (Denmark)

    Yongsiri, C.; Vollertsen, J.; Rasmussen, M. R.

    2004-01-01

    The emissions process of hydrogen sulfide was studied to quantify air–water transfer of hydrogen sulfide in sewer networks. Hydrogen sulfide transfer across the air–water interface was investigated at different turbulence levels (expressed in terms of the Froude number) and pH using batch...... experiments. By means of the overall mass–transfer coefficient (KLa), the transfer coefficient of hydrogen sulfide (KLaH2S), referring to total sulfide, was correlated to that of oxygen (KLaO2) (i.e., the reaeration coefficient). Results demonstrate that both turbulence and pH in the water phase play...... a significant role for KLaH2S. An exponential expression is a suitable representation for the relationship between KLaH2S and the Froude number at all pH values studied (4.5 to 8.0). Because of the dissociation of hydrogen sulfide, KLaH2S increased with decreasing pH at a constant turbulence level. Relative...

  1. Na, Rb and Cs partitioning between metal, silicate and sulfide: Implications for volatile depletion in terrestrial planets

    Science.gov (United States)

    Boujibar, A.; Fei, Y.; Du, Z.; Righter, K.; Bullock, E. S.

    2017-12-01

    Inner Solar System materials are known for their depletion in volatile elements, including the moderately volatile alkalis: Na, K, Rb, and Cs. The origin of this depletion is still uncertain, as several processes could have been involved, during the nebular condensation or planetary accretion. Volatile depletion is commonly estimated through comparison of alkali concentrations relatively to those of chondrites, assuming they remain in planetary mantles during core segregation. However, experimental studies show that substantial K can partition into metals that are enriched in sulfur and oxygen. Several models have also suggested that sulfides may have played an important role during episodes of sulfide segregation from a crystallizing magma ocean (sulfide matte) or accretion of S-rich planetary embryos. For Mercury, a sulfide layer could be present between core and mantle, due to immiscibility between Si-rich and S-rich metals. Therefore, here we investigate whether alkali elements (Na, Cs and Rb) could be partly sequestered in planetary cores during their differentiation. We conducted experiments at high pressure and temperature (1 to 5 GPa and up to 1900 °C) to determine partition coefficients of Na, Rb and Cs between metal and silicate. Our results show that pressure, temperature, sulfur and oxygen in metals enhance the partitioning of Na, Rb and Cs into metals, as previously found for K. For all three investigated alkalis (Na, Rb and Cs), we found a maximum partition coefficient of 1 between sulfides containing 13 wt% O and silicate melt. Therefore, S-rich cores or sulfide layers formed due to immiscibility in Fe-S-O systems could have acted as important geochemical reservoirs for alkali elements. Using our experimental data and different assumptions on initial bulk abundances, we evaluate volatile depletion in terrestrial planets, by comparing resulting mantle alkali concentrations after core segregation, with actual concentrations in the Earth's mantle.

  2. Recent mercury contamination from artisanal gold mining on Buru Island, Indonesia – Potential future risks to environmental health and food safety

    International Nuclear Information System (INIS)

    Male, Yusthinus Thobias; Reichelt-Brushett, Amanda Jean; Pocock, Matt; Nanlohy, Albert

    2013-01-01

    Highlights: • Recent mercury contamination from artisanal gold mining, Buru Island, Indonesia. • Measured dispersal into the marine environment. • Implications for food safety. • Challenges for introducing mercury reduction strategies. -- Abstract: In November 2011 gold was found at Mount Botak, Buru Island, Mollucas Province, Indonesia. Since 2012 mercury has been used to extract the gold requiring large volumes of water and resulting in deposition of mercury into Wamsait River and Kayeli Bay. Total mercury in waste ponds was over 680 mg/kg. In sediments at the mouth of the local river and a small feeder creek >3.00 mg/kg and >7.66 mg/kg respectively. River and bay sediments were proportionately higher in available mercury than elemental mercury and more strongly bound mercuric sulfide compared to that in trommel waste. This preliminary investigation raises concerns about the long term distribution and speciation of mercury. The floodplain is an important agricultural resource, and Mollucas Province is recognised nationally as the centre for Indonesian fish stocks. Challenges for management include communicating the potential future risks to the community and leaders and identifying mechanisms to reduce mercury waste

  3. Method and apparatus for sampling atmospheric mercury

    Science.gov (United States)

    Trujillo, Patricio E.; Campbell, Evan E.; Eutsler, Bernard C.

    1976-01-20

    A method of simultaneously sampling particulate mercury, organic mercurial vapors, and metallic mercury vapor in the working and occupational environment and determining the amount of mercury derived from each such source in the sampled air. A known volume of air is passed through a sampling tube containing a filter for particulate mercury collection, a first adsorber for the selective adsorption of organic mercurial vapors, and a second adsorber for the adsorption of metallic mercury vapor. Carbon black molecular sieves are particularly useful as the selective adsorber for organic mercurial vapors. The amount of mercury adsorbed or collected in each section of the sampling tube is readily quantitatively determined by flameless atomic absorption spectrophotometry.

  4. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors

    NARCIS (Netherlands)

    Villa Gomez, D.K.; Cassidy, J.; Keesman, K.J.; Sampaio, R.M.; Lens, P.N.L.

    2014-01-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4 2- ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing

  5. Highly Reducing Partitioning Experiments Relevant to the Planet Mercury

    Science.gov (United States)

    Rowland, Rick, II; Vander Kaaden, Kathleen E.; McCubbin, Francis M.; Danielson, Lisa R.

    2017-01-01

    With the data returned from the MErcury Surface Space ENvironment GEochemistry and Ranging (MESSENGER) mission, there are now numerous constraints on the physical and chemical properties of Mercury, including its surface composition. The high S and low FeO contents observed from MESSENGER on the planet's surface suggests a low oxygen fugacity of the present planetary materials. Estimates of the oxygen fugacity for Mercurian magmas are approximately 3-7 log units below the Iron-Wüstite (Fe-FeO) oxygen buffer, several orders of magnitude more reducing than other terrestrial bodies we have data from such as the Earth, Moon, or Mars. Most of our understanding of elemental partitioning behavior comes from observations made on terrestrial rocks, but Mercury's oxygen fugacity is far outside the conditions of those samples. With limited oxygen available, lithophile elements may instead exhibit chalcophile, halophile, or siderophile behaviors. Furthermore, very few natural samples of rocks that formed under reducing conditions are available in our collections (e.g., enstatite chondrites, achondrites, aubrites). With this limited amount of material, we must perform experiments to determine the elemental partitioning behavior of typically lithophile elements as a function of decreasing oxygen fugacity. Experiments are being conducted at 4 GPa in an 880-ton multi-anvil press, at temperatures up to 1850degC. The composition of starting materials for the experiments were selected for the final run products to contain metal, silicate melt, and sulfide melt phases. Oxygen fugacity is controlled in the experiments by adding silicon metal to the samples, using the Si-SiO2 oxygen buffer, which is approximately 5 log units more reducing than the Fe-FeO oxygen buffer at our temperatures of interest. The target silicate melt compositional is diopside (CaMgSi2O6) because measured surface compositions indicate partial melting of a pyroxene-rich mantle. Elements detected on Mercury

  6. Mercury analysis in hair

    DEFF Research Database (Denmark)

    Esteban, Marta; Schindler, Birgit Karin; Jiménez, José Antonio

    2015-01-01

    laboratories. Training sessions were organized for field workers and four external quality-assessment exercises (ICI/EQUAS), followed by the corresponding web conferences, were organized between March 2011 and February 2012. ICI/EQUAS used native hair samples at two mercury concentration ranges (0...

  7. Mercury exposure in Ireland

    DEFF Research Database (Denmark)

    Cullen, Elizabeth; Evans, David S; Davidson, Fred

    2014-01-01

    of a study to Coordinate and Perform Human Biomonitoring on a European Scale (DEMOCOPHES) pilot biomonitoring study. METHODS: Hair mercury concentrations were determined from a convenience sample of 120 mother/child pairs. Mothers also completed a questionnaire. Rigorous quality assurance within DEMOCOPHES...

  8. Metabolic models for methyl and inorganic mercury

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, S.R.; Purdue, P.

    1984-03-01

    Following the outbreak of mercury poisoning in Minimata, Japan (1953-60), much work has been done on the toxicology of mercury - in particular methyl mercury. In this paper, the authors derive two compartmental models for the metabolism of methyl mercury and inorganic mercury based upon the data which have been collected since 1960.

  9. [Mercury in vaccines].

    Science.gov (United States)

    Hessel, Luc

    2003-01-01

    Thiomersal, also called thimerosal, is an ethyl mercury derivative used as a preservative to prevent bacterial contamination of multidose vaccine vials after they have been opened. Exposure to low doses of thiomersal has essentially been associated with hypersensitivity reactions. Nevertheless there is no evidence that allergy to thiomersal could be induced by thiomersal-containing vaccines. Allergy to thiomersal is usually of delayed-hypersensitivity type, but its detection through cutaneous tests is not very reliable. Hypersensitivity to thiomersal is not considered as a contraindication to the use of thiomersal-containing vaccines. In 1999 in the USA, thiomersal was present in approximately 30 different childhood vaccines, whereas there were only 2 in France. Although there were no evidence of neurological toxicity in infants related to the use of thiomersal-containing vaccines, the FDA considered that the cumulative dose of mercury received by young infants following vaccination was high enough (although lower than the FDA threshold for methyl mercury) to request vaccine manufacturers to remove thiomersal from vaccine formulations. Since 2002, all childhood vaccines used in Europe and the USA are thiomersal-free or contain only minute amounts of thiomersal. Recently published studies have shown that the mercury levels in the blood, faeces and urine of children who had received thiomersal-containing vaccines were much lower than those accepted by the American Environmental Protection Agency. It has also been demonstrated that the elimination of mercury in children was much faster than what was expected on the basis of studies conducted with methyl mercury originating from food. Recently, the hypothesis that mercury contained in vaccines could be the cause of autism and other neurological developmental disorders created a new debate in the medical community and the general public. To date, none of the epidemiological studies conducted in Europe and elsewhere

  10. Mercury Information Clearinghouse

    Energy Technology Data Exchange (ETDEWEB)

    Chad A. Wocken; Michael J. Holmes; Dennis L. Laudal; Debra F. Pflughoeft-Hassett; Greg F. Weber; Nicholas V. C. Ralston; Stanley J. Miller; Grant E. Dunham; Edwin S. Olson; Laura J. Raymond; John H. Pavlish; Everett A. Sondreal; Steven A. Benson

    2006-03-31

    The Canadian Electricity Association (CEA) identified a need and contracted the Energy & Environmental Research Center (EERC) to create and maintain an information clearinghouse on global research and development activities related to mercury emissions from coal-fired electric utilities. With the support of CEA, the Center for Air Toxic Metals{reg_sign} (CATM{reg_sign}) Affiliates, and the U.S. Department of Energy (DOE), the EERC developed comprehensive quarterly information updates that provide a detailed assessment of developments in the various areas of mercury monitoring, control, policy, and research. A total of eight topical reports were completed and are summarized and updated in this final CEA quarterly report. The original quarterly reports can be viewed at the CEA Web site (www.ceamercuryprogram.ca). In addition to a comprehensive update of previous mercury-related topics, a review of results from the CEA Mercury Program is provided. Members of Canada's coal-fired electricity generation sector (ATCO Power, EPCOR, Manitoba Hydro, New Brunswick Power, Nova Scotia Power Inc., Ontario Power Generation, SaskPower, and TransAlta) and CEA, have compiled an extensive database of information from stack-, coal-, and ash-sampling activities. Data from this effort are also available at the CEA Web site and have provided critical information for establishing and reviewing a mercury standard for Canada that is protective of environment and public health and is cost-effective. Specific goals outlined for the CEA mercury program included the following: (1) Improve emission inventories and develop management options through an intensive 2-year coal-, ash-, and stack-sampling program; (2) Promote effective stack testing through the development of guidance material and the support of on-site training on the Ontario Hydro method for employees, government representatives, and contractors on an as-needed basis; (3) Strengthen laboratory analytical capabilities through

  11. Pathways for Energization of Ca in Mercury's Exosphere

    Science.gov (United States)

    Killen, Rosemary M.

    2015-01-01

    We investigate the possible pathways to produce the extreme energy observed in the calcium exosphere of Mercury. Any mechanism must explain the facts that Ca in Mercury's exosphere is extremely hot, that it is seen almost exclusively on the dawnside of the planet, and that its content varies seasonally, not sporadically. Simple diatomic molecules or their clusters are considered, focusing on calcium oxides while acknowledging that Ca sulfides may also be the precursor molecules. We first discuss impact vaporization to justify the assumption that CaO and Ca-oxide clusters are expected from impacts on Mercury. Then we discuss processes by which the atomic Ca is energized to a 70,000 K gas. The processes considered are (1) electron-impact dissociation of CaO molecules, (2) spontaneous dissociation of Ca-bearing molecules following impact vaporization, (3) shock-induced dissociative ionization, (4) photodissociation and (5) sputtering. We conclude that electron-impact dissociation cannot produce the required abundance of Ca, and sputtering cannot reproduce the observed spatial and temporal variation that is measured. Spontaneous dissociation is unlikely to result in the high energy that is seen. Of the two remaining processes, shock induced dissociative ionization produces the required energy and comes close to producing the required abundance, but rates are highly dependent on the incoming velocity distribution of the impactors. Photodissociation probably can produce the required abundance of Ca, but simulations show that photodissociation cannot reproduce the observed spatial distribution.

  12. Small Mercury Relativity Orbiter

    Science.gov (United States)

    Bender, Peter L.; Vincent, Mark A.

    1989-01-01

    The accuracy of solar system tests of gravitational theory could be very much improved by range and Doppler measurements to a Small Mercury Relativity Orbiter. A nearly circular orbit at roughly 2400 km altitude is assumed in order to minimize problems with orbit determination and thermal radiation from the surface. The spacecraft is spin-stabilized and has a 30 cm diameter de-spun antenna. With K-band and X-band ranging systems using a 50 MHz offset sidetone at K-band, a range accuracy of 3 cm appears to be realistically achievable. The estimated spacecraft mass is 50 kg. A consider-covariance analysis was performed to determine how well the Earth-Mercury distance as a function of time could be determined with such a Relativity Orbiter. The minimum data set is assumed to be 40 independent 8-hour arcs of tracking data at selected times during a two year period. The gravity field of Mercury up through degree and order 10 is solved for, along with the initial conditions for each arc and the Earth-Mercury distance at the center of each arc. The considered parameters include the gravity field parameters of degree 11 and 12 plus the tracking station coordinates, the tropospheric delay, and two parameters in a crude radiation pressure model. The conclusion is that the Earth-Mercury distance can be determined to 6 cm accuracy or better. From a modified worst-case analysis, this would lead to roughly 2 orders of magnitude improvement in the knowledge of the precession of perihelion, the relativistic time delay, and the possible change in the gravitational constant with time.

  13. Mining legacy across a wetland landscape: high mercury in Upper Peninsula (Michigan) rivers, lakes, and fish.

    Science.gov (United States)

    Kerfoot, W Charles; Urban, Noel R; McDonald, Cory P; Zhang, Huanxin; Rossmann, Ronald; Perlinger, Judith A; Khan, Tanvir; Hendricks, Ashley; Priyadarshini, Mugdha; Bolstad, Morgan

    2018-03-29

    A geographic enigma is that present-day atmospheric deposition of mercury in the Upper Peninsula of Michigan is low (48%) and that regional industrial emissions have declined substantially (ca. 81% reduction) relative to downstate. Mercury levels should be declining. However, state (MDEQ) surveys of rivers and lakes revealed elevated total mercury (THg) in Upper Peninsula waters and sediment relative to downstate. Moreover, Western Upper Peninsula (WUP) fish possess higher methyl mercury (MeHg) levels than Northern Lower Peninsula (NLP) fish. A contributing explanation for elevated THg loading is that a century ago the Upper Peninsula was a major industrial region, centered on mining. Many regional ores (silver, copper, zinc, massive sulfides) contain mercury in part per million concentrations. Copper smelters and iron furnace-taconite operations broadcast mercury almost continuously for 140 years, whereas mills discharged tailings and old mine shafts leaked contaminated water. We show that mercury emissions from copper and iron operations were substantial (60-650 kg per year) and dispersed over relatively large areas. Moreover, lake sediments in the vicinity of mining operations have higher THg concentrations. Sediment profiles from the Keweenaw Waterway show that THg accumulation increased 50- to 400-fold above modern-day atmospheric deposition levels during active mining and smelting operations, with lingering MeHg effects. High MeHg concentrations are geographically correlated with low pH and dissolved organic carbon (DOC), a consequence of biogeochemical cycling in wetlands, characteristic of the Upper Peninsula. DOC can mobilize metals and elevate MeHg concentrations. We argue that mercury loading from mining is historically superimposed upon strong regional wetland effects, producing a combined elevation of both THg and MeHg in the Western Upper Peninsula.

  14. Mercury Phase II Study - Mercury Behavior in Salt Processing Flowsheet

    Energy Technology Data Exchange (ETDEWEB)

    Jain, V. [Savannah River Remediation, LLC., Aiken, SC (United States); Shah, H. [Savannah River Remediation, LLC., Aiken, SC (United States). Sludge and Salt Planning; Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wilmarth, W. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-25

    Mercury (Hg) in the Savannah River Site Liquid Waste System (LWS) originated from decades of canyon processing where it was used as a catalyst for dissolving the aluminum cladding of reactor fuel. Approximately 60 metric tons of mercury is currently present throughout the LWS. Mercury has long been a consideration in the LWS, from both hazard and processing perspectives. In February 2015, a Mercury Program Team was established at the request of the Department of Energy to develop a comprehensive action plan for long-term management and removal of mercury. Evaluation was focused in two Phases. Phase I activities assessed the Liquid Waste inventory and chemical processing behavior using a system-by-system review methodology, and determined the speciation of the different mercury forms (Hg+, Hg++, elemental Hg, organomercury, and soluble versus insoluble mercury) within the LWS. Phase II activities are building on the Phase I activities, and results of the LWS flowsheet evaluations will be summarized in three reports: Mercury Behavior in the Salt Processing Flowsheet (i.e. this report); Mercury Behavior in the Defense Waste Processing Facility (DWPF) Flowsheet; and Mercury behavior in the Tank Farm Flowsheet (Evaporator Operations). The evaluation of the mercury behavior in the salt processing flowsheet indicates, inter alia, the following: (1) In the assembled Salt Batches 7, 8 and 9 in Tank 21, the total mercury is mostly soluble with methylmercury (MHg) contributing over 50% of the total mercury. Based on the analyses of samples from 2H Evaporator feed and drop tanks (Tanks 38/43), the source of MHg in Salt Batches 7, 8 and 9 can be attributed to the 2H evaporator concentrate used in assembling the salt batches. The 2H Evaporator is used to evaporate DWPF recycle water. (2) Comparison of data between Tank 21/49, Salt Solution Feed Tank (SSFT), Decontaminated Salt Solution Hold Tank (DSSHT), and Tank 50 samples suggests that the total mercury as well as speciated

  15. Mercury Phase II Study - Mercury Behavior in Salt Processing Flowsheet

    International Nuclear Information System (INIS)

    Jain, V.; Shah, H.; Wilmarth, W. R.

    2016-01-01

    Mercury (Hg) in the Savannah River Site Liquid Waste System (LWS) originated from decades of canyon processing where it was used as a catalyst for dissolving the aluminum cladding of reactor fuel. Approximately 60 metric tons of mercury is currently present throughout the LWS. Mercury has long been a consideration in the LWS, from both hazard and processing perspectives. In February 2015, a Mercury Program Team was established at the request of the Department of Energy to develop a comprehensive action plan for long-term management and removal of mercury. Evaluation was focused in two Phases. Phase I activities assessed the Liquid Waste inventory and chemical processing behavior using a system-by-system review methodology, and determined the speciation of the different mercury forms (Hg+, Hg++, elemental Hg, organomercury, and soluble versus insoluble mercury) within the LWS. Phase II activities are building on the Phase I activities, and results of the LWS flowsheet evaluations will be summarized in three reports: Mercury Behavior in the Salt Processing Flowsheet (i.e. this report); Mercury Behavior in the Defense Waste Processing Facility (DWPF) Flowsheet; and Mercury behavior in the Tank Farm Flowsheet (Evaporator Operations). The evaluation of the mercury behavior in the salt processing flowsheet indicates, inter alia, the following: (1) In the assembled Salt Batches 7, 8 and 9 in Tank 21, the total mercury is mostly soluble with methylmercury (MHg) contributing over 50% of the total mercury. Based on the analyses of samples from 2H Evaporator feed and drop tanks (Tanks 38/43), the source of MHg in Salt Batches 7, 8 and 9 can be attributed to the 2H evaporator concentrate used in assembling the salt batches. The 2H Evaporator is used to evaporate DWPF recycle water. (2) Comparison of data between Tank 21/49, Salt Solution Feed Tank (SSFT), Decontaminated Salt Solution Hold Tank (DSSHT), and Tank 50 samples suggests that the total mercury as well as speciated

  16. A mercury transport and fate model (LM2-mercury) for mass budget assessment of mercury cycling in Lake Michigan

    Science.gov (United States)

    LM2-Mercury, a mercury mass balance model, was developed to simulate and evaluate the transport, fate, and biogeochemical transformations of mercury in Lake Michigan. The model simulates total suspended solids (TSS), disolved organic carbon (DOC), and total, elemental, divalent, ...

  17. Mercury stabilization in chemically bonded phosphate ceramics

    International Nuclear Information System (INIS)

    Wagh, A. S.; Singh, D.; Jeong, S. Y.

    2000-01-01

    Mercury stabilization and solidification is a significant challenge for conventional stabilization technologies. This is because of the stringent regulatory limits on leaching of its stabilized products. In a conventional cement stabilization process, Hg is converted at high pH to its hydroxide, which is not a very insoluble compound; hence the preferred route for Hg sulfidation to convert it into insoluble cinnabar (HgS). Unfortunately, efficient formation of this compound is pH-dependent. At a high pH, one obtains a more soluble Hg sulfate, in a very low pH range, insufficient immobilization occurs because of the escape of hydrogen sulfide, while efficient formation of HgS occurs only in a moderately acidic region. Thus, the pH range of 4 to 8 is where stabilization with Chemically Bonded Phosphate Ceramics (CBPC) is carried out. This paper discusses the authors experience on bench-scale stabilization of various US Department of Energy (DOE) waste streams containing Hg in the CBPC process. This process was developed to treat DOE's mixed waste streams. It is a room-temperature-setting process based on an acid-base reaction between magnesium oxide and monopotassium phosphate solution that forms a dense ceramic within hours. For Hg stabilization, addition of a small amount ( 2 S or K 2 S is sufficient in the binder composition. Here the Toxicity Characteristic Leaching Procedure (TCLP) results on CBPC waste forms of surrogate waste streams representing secondary Hg containing wastes such as combustion residues and Delphi DETOXtrademark residues are presented. The results show that although the current limit on leaching of Hg is 0.2 mg/L, the results from the CBPC waste forms are at least one order lower than this stringent limit. Encouraged by these results on surrogate wastes, they treated actual low-level Hg-containing mixed waste from their facility at Idaho. TCLP results on this waste are presented here. The efficient stabilization in all these cases is

  18. Mercury Exposure and Heart Diseases.

    Science.gov (United States)

    Genchi, Giuseppe; Sinicropi, Maria Stefania; Carocci, Alessia; Lauria, Graziantonio; Catalano, Alessia

    2017-01-12

    Environmental contamination has exposed humans to various metal agents, including mercury. It has been determined that mercury is not only harmful to the health of vulnerable populations such as pregnant women and children, but is also toxic to ordinary adults in various ways. For many years, mercury was used in a wide variety of human activities. Nowadays, the exposure to this metal from both natural and artificial sources is significantly increasing. Recent studies suggest that chronic exposure, even to low concentration levels of mercury, can cause cardiovascular, reproductive, and developmental toxicity, neurotoxicity, nephrotoxicity, immunotoxicity, and carcinogenicity. Possible biological effects of mercury, including the relationship between mercury toxicity and diseases of the cardiovascular system, such as hypertension, coronary heart disease, and myocardial infarction, are being studied. As heart rhythm and function are under autonomic nervous system control, it has been hypothesized that the neurotoxic effects of mercury might also impact cardiac autonomic function. Mercury exposure could have a long-lasting effect on cardiac parasympathetic activity and some evidence has shown that mercury exposure might affect heart rate variability, particularly early exposures in children. The mechanism by which mercury produces toxic effects on the cardiovascular system is not fully elucidated, but this mechanism is believed to involve an increase in oxidative stress. The exposure to mercury increases the production of free radicals, potentially because of the role of mercury in the Fenton reaction and a reduction in the activity of antioxidant enzymes, such as glutathione peroxidase. In this review we report an overview on the toxicity of mercury and focus our attention on the toxic effects on the cardiovascular system.

  19. Mercury Exposure and Heart Diseases

    Directory of Open Access Journals (Sweden)

    Giuseppe Genchi

    2017-01-01

    Full Text Available Environmental contamination has exposed humans to various metal agents, including mercury. It has been determined that mercury is not only harmful to the health of vulnerable populations such as pregnant women and children, but is also toxic to ordinary adults in various ways. For many years, mercury was used in a wide variety of human activities. Nowadays, the exposure to this metal from both natural and artificial sources is significantly increasing. Recent studies suggest that chronic exposure, even to low concentration levels of mercury, can cause cardiovascular, reproductive, and developmental toxicity, neurotoxicity, nephrotoxicity, immunotoxicity, and carcinogenicity. Possible biological effects of mercury, including the relationship between mercury toxicity and diseases of the cardiovascular system, such as hypertension, coronary heart disease, and myocardial infarction, are being studied. As heart rhythm and function are under autonomic nervous system control, it has been hypothesized that the neurotoxic effects of mercury might also impact cardiac autonomic function. Mercury exposure could have a long-lasting effect on cardiac parasympathetic activity and some evidence has shown that mercury exposure might affect heart rate variability, particularly early exposures in children. The mechanism by which mercury produces toxic effects on the cardiovascular system is not fully elucidated, but this mechanism is believed to involve an increase in oxidative stress. The exposure to mercury increases the production of free radicals, potentially because of the role of mercury in the Fenton reaction and a reduction in the activity of antioxidant enzymes, such as glutathione peroxidase. In this review we report an overview on the toxicity of mercury and focus our attention on the toxic effects on the cardiovascular system.

  20. Mercury's exosphere: observations during MESSENGER's First Mercury flyby.

    Science.gov (United States)

    McClintock, William E; Bradley, E Todd; Vervack, Ronald J; Killen, Rosemary M; Sprague, Ann L; Izenberg, Noam R; Solomon, Sean C

    2008-07-04

    During MESSENGER's first Mercury flyby, the Mercury Atmospheric and Surface Composition Spectrometer measured Mercury's exospheric emissions, including those from the antisunward sodium tail, calcium and sodium close to the planet, and hydrogen at high altitudes on the dayside. Spatial variations indicate that multiple source and loss processes generate and maintain the exosphere. Energetic processes connected to the solar wind and magnetospheric interaction with the planet likely played an important role in determining the distributions of exospheric species during the flyby.

  1. Recovery of mercury from acid waste residues

    Science.gov (United States)

    Greenhalgh, Wilbur O.

    1989-12-05

    Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and then quenching the reactivity of the nitric acid prior to nitration of the mercury metal.

  2. Mercury Poisoning Linked to Skin Products

    Science.gov (United States)

    ... Products For Consumers Home For Consumers Consumer Updates Mercury Poisoning Linked to Skin Products Share Tweet Linkedin ... and, in some situations, criminal prosecution. Dangers of Mercury Exposure to mercury can have serious health consequences. ...

  3. Mercury in the Carson and Truckee River basins of Nevada

    Science.gov (United States)

    Van Denburgh, A.S.

    1973-01-01

    Upstream from major pre-1900 ore milling in the Carson and Truckee River basins, "background" concentrations of total mercury in the upper 1 to 3 inches of sand- to clay-sized stream-bottom sediment are less than 0.1 ug/g (microgram per gram). Downstream, measured concentrations were as much as 200 times the background level. Greatest concentrations were encountered in the Carson River basin within and immediately upstream from Lahontan Reservoir. Data from for the Carson River near Fort Churchill suggest that most of the mercury in the sampled bottom sediment may be present as mercuric sulfide or as a component of one of more non-methyl organic compounds or complexes, rather than existing in the metallic state. Regardless of state, this reservoir of mercury is of concern because of its possible availability to the aquatic food chain and, ultimately, to man. Among 48 samples of surface water from 29 sites in the two basins, the maximum measured total-mercury concentration was 6.3 ug/1 (micrograms per liter), for a sample from the Carson River near Fort Churchill. Except downstream from Lahontan Reservoir, most other measured values were less than 1 ug/1. (The U.S> Environmental Protection Agency interim limit for drinking water is 5 ug/1.) The total-mercury content of stream water is related to the mercury content of bottom sediments and the rate of streamflow, because the latter affects the suspended-sediment transporting capability of the stream,. Near Fort Churchill, total-mercury concentrations that might be expected at streamflows greater than those of 1971-72 are: as much as 10-15 ug/1 or more at 2,000 cfs (cubic feet per second), and as much as 10-20 ug/1 or more at 3,000 cfs. Elsewhere, expectable concentrations are much less because the bottom sediment contains much less mercury. The mercury contents of water samples from 36 wells in the Carson and Truckee basins were all less than 1 ug/1, indicating that mercury is not a problem in ground water, even

  4. The new ret process for hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, S.; Onishi, H.

    1977-11-01

    It was developed for gas streams from rayon production containing either 4500 ppM hydrogen sulfide and 5 ppM carbon disulfide or 900 ppM hydrogen sulfide and 16 ppM carbon disulfide (average values). The process consists of absorption towers, alkali scrubbers for the recovery of carbon disulfide, and an oxidation reactor. The process is catalyzed by an organic iron complex catalyst. For the removal of 1 kg hydrogen sulfide, the process uses 130 g sodium hydroxide, catalyst (20 yen), 2.5 kw-hr electricity, 15 kg steam (3 kg in winter), 2 cu m cooling water (1 cu m in winter), and 8 l. fresh water. The recovered sulfur (99%) is 99.9% pure. Eight litres of 0.03 kg COD wastewater are also produced. The process equipment is described. Flow diagrams, graph, and tables.

  5. Mercury, Vaccines, and Autism

    Science.gov (United States)

    Baker, Jeffrey P.

    2008-01-01

    The controversy regarding the once widely used mercury-containing preservative thimerosal in childhood vaccines has raised many historical questions that have not been adequately explored. Why was this preservative incorporated in the first place? Was there any real evidence that it caused harm? And how did thimerosal become linked in the public mind to the “autism epidemic”? I examine the origins of the thimerosal controversy and their legacy for the debate that has followed. More specifically, I explore the parallel histories of three factors that converged to create the crisis: vaccine preservatives, mercury poisoning, and autism. An understanding of this history provides important lessons for physicians and policymakers seeking to preserve the public’s trust in the nation’s vaccine system. PMID:18172138

  6. Mercury in Canadian crude oil

    International Nuclear Information System (INIS)

    Hollebone, B.P.

    2005-01-01

    Estimates for average mercury concentrations in crude oil range widely from 10 ng/g of oil to 3,500 ng/g of oil. With such a broad range of estimates, it is difficult to determine the contributions of the petroleum sector to the total budget of mercury emissions. In response to concerns that the combustion of petroleum products may be a major source of air-borne mercury pollution, Environment Canada and the Canadian Petroleum Products Institute has undertaken a survey of the average total mercury concentration in crude oil processed in Canadian refineries. In order to calculate the potential upper limit of total mercury in all refined products, samples of more than 30 different types of crude oil collected from refineries were measured for their concentration of mercury as it enters into a refinery before processing. High temperature combustion, cold vapour atomic absorption and cold vapour atomic fluorescence were the techniques used to quantify mercury in the samples. The results of the study provide information on the total mass of mercury present in crude oil processed in Canada each year. Results can be used to determine the impact of vehicle exhaust emissions to the overall Canadian mercury emission budget. 17 refs., 2 tabs., 2 figs

  7. Kinetics of microbially mediated methylation of mercury in aerobic and anaerobic aquatic environments

    Energy Technology Data Exchange (ETDEWEB)

    Bisogni, J.J. Jr.

    1973-01-01

    In this research the microbial transformation of inorganic mercury to organic mercury (monomethyl- and dimethylmercury) was studied. This transformation was studied with regard to the effects of the following: (1) redox potential, (2) inorganic mercury concentration, (3) temperature, (4) microbial activity, and (5) sulfide concentration. A kinetic model was proposed to describe the rate of methylation. The model included the following parameters: (1) a coefficient which indicated relative microbial activity, (2) a coefficient which indicated biochemical availability of the inorganic mercury, (3) a parameter whose value was determined by the system redox potential, and (4) inorganic mercury concentration. Experimental verification of the model and evaluation of system specific model coefficients were accomplished with laboratory scale microbial reactors. Reactors were operated under both anaerobic and aerobic conditions at microbial specific growth rates of 1/6, 1/12, and 1/24 per day. Methylation rates were determined at 10/sup 0/C, 20/sup 0/C, and 30/sup 0/C in these reactors. An analytical procedure was developed to determine monomethyl- and dimethylmercury. The accuracy and precision of this procedure was experimentally verified.

  8. Refractory sulfides as IR window materials

    Science.gov (United States)

    White, William B.

    1990-10-01

    The development of sulfide materials as infrared-transmitting optical ceramics is limited by intrinsic optical properties, thermomechanical properties, and considerations of chemical stability. Screening procedures with respect to band gap, electronic absorption, chemical stability, and refractory character reduced the set of all sulfides to about a dozen structural families. Systematic relationships were developed between crystal chemistry and phonon absorption edge, vibrational modes frequencies, and coefficient of thermal expansion which allow possible ranges of properties to be estimated. It is concluded that improved materials are possible but that radically improved new materials are unlikely.

  9. Iron-sulfide crystals in probe deposits

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming

    1998-01-01

    Iron-sulfides were observed in deposits collected on a probe inserted at the top of the furnace of a coal-fired power station in Denmark. The chemical composition of the iron-sulfides is equivalent to pyrrhotite (FeS). The pyrrhotites are present as crystals and, based on the shape of the crystals......, it was deduced that they were not deposited but instead grew within the deposit. The presence of unburned char particles within the deposits supports the concept that a reducing environment existed in the deposits. Two processes are proposed for explaining the existence of pyrrhotite crystals within a deposit...

  10. Acute inhalation toxicity of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.M.; Hahn, F.F.; Barr, E.B. [and others

    1995-12-01

    Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

  11. Method for mercury refinement

    Science.gov (United States)

    Grossman, M.W.; Speer, R.; George, W.A.

    1991-04-09

    The effluent from mercury collected during the photochemical separation of the [sup 196]Hg isotope is often contaminated with particulate mercurous chloride, Hg[sub 2]Cl[sub 2]. The use of mechanical filtering via thin glass tubes, ultrasonic rinsing with acetone (dimethyl ketone) and a specially designed cold trap have been found effective in removing the particulate (i.e., solid) Hg[sub 2]Cl[sub 2] contaminant. The present invention is particularly directed to such filtering. 5 figures.

  12. Apparatus for mercury refinement

    Science.gov (United States)

    Grossman, M.W.; Speer, R.; George, W.A.

    1991-07-16

    The effluent from mercury collected during the photochemical separation of the [sup 196]Hg isotope is often contaminated with particulate mercurous chloride, Hg[sub 2]Cl[sub 2]. The use of mechanical filtering via thin glass tubes, ultrasonic rinsing with acetone (dimethyl ketone) and a specially designed cold trap have been found effective in removing the particulate (i.e., solid) Hg[sub 2]Cl[sub 2] contaminant. The present invention is particularly directed to such filtering. 5 figures.

  13. Apparatus for mercury refinement

    International Nuclear Information System (INIS)

    Grossman, M.W.; Speer, R.; George, W.A.

    1991-01-01

    The effluent from mercury collected during the photochemical separation of the 196 Hg isotope is often contaminated with particulate mercurous chloride, Hg 2 Cl 2 . The use of mechanical filtering via thin glass tubes, ultrasonic rinsing with acetone (dimethyl ketone) and a specially designed cold trap have been found effective in removing the particulate (i.e., solid) Hg 2 Cl 2 contaminant. The present invention is particularly directed to such filtering. 5 figures

  14. Method for scavenging mercury

    Science.gov (United States)

    Chang, Shih-ger [El Cerrito, CA; Liu, Shou-heng [Kaohsiung, TW; Liu, Zhao-rong [Beijing, CN; Yan, Naiqiang [Berkeley, CA

    2009-01-20

    Disclosed herein is a method for removing mercury from a gas stream comprising contacting the gas stream with a getter composition comprising bromine, bromochloride, sulphur bromide, sulphur dichloride or sulphur monochloride and mixtures thereof. In one preferred embodiment the getter composition is adsorbed onto a sorbent. The sorbent may be selected from the group consisting of flyash, limestone, lime, calcium sulphate, calcium sulfite, activated carbon, charcoal, silicate, alumina and mixtures thereof. Preferred is flyash, activated carbon and silica.

  15. Magnetic field of Mercury

    International Nuclear Information System (INIS)

    Jackson, D.J.; Beard, D.B.

    1977-01-01

    The geomagnetic field, suitably scaled down and parameterized, is shown to give a very good fit to the magnetic field measurements taken on the first and third passes of the Mariner 10 space probe past Mercury. The excellence of the fit to a reliable planetary magnetospheric model is good evidence that the Mercury magnetosphere is formed by a simple, permanent, intrinsic planetary magnetic field distorted by the effects of the solar wind. The parameters used for a best fit to all the data are (depending slightly on the choice of data) 2.44--2.55 for the ratio of Mercury's magnetic field strength at the subsolar point to that of the earth's subsolar point field (this results in a dipole moment of 170 γR/sub M/ 3 (R/sub M/ is Mercury Radius), i.e., 2.41 x 10 22 G cm 3 in the same direction as the earth's dipole), approx.-113 γR/sub M/ 4 for the planetary quadrupole moment parallel to the dipole moment, 10degree--17degree for the tilt of the planet dipole toward the sun, 4.5degree for the tilt of the dipole toward dawn, and 2.5degree--7.6degree aberration angle for the shift in the tail axis from the planet-sun direction because of the planet's orbital velocity. The rms deviation overall for the entire data set compared with the theoretical fitted model for the magnetic field strength was 17 γ (approx.4% of the maximum field measured). If the data from the first pass that show presumed strong time variations are excluded, the overall rms deviation for the field magnitude is only 10 γ

  16. The planet Mercury (1971)

    Science.gov (United States)

    1972-01-01

    The physical properties of the planet Mercury, its surface, and atmosphere are presented for space vehicle design criteria. The mass, dimensions, mean density, and orbital and rotational motions are described. The gravity field, magnetic field, electromagnetic radiation, and charged particles in the planet's orbit are discussed. Atmospheric pressure, temperature, and composition data are given along with the surface composition, soil mechanical properties, and topography, and the surface electromagnetic and temperature properties.

  17. Membrane for hydrogen recovery from streams containing hydrogen sulfide

    Science.gov (United States)

    Agarwal, Pradeep K.

    2007-01-16

    A membrane for hydrogen recovery from streams containing hydrogen sulfide is provided. The membrane comprises a substrate, a hydrogen permeable first membrane layer deposited on the substrate, and a second membrane layer deposited on the first layer. The second layer contains sulfides of transition metals and positioned on the on a feed side of the hydrogen sulfide stream. The present invention also includes a method for the direct decomposition of hydrogen sulfide to hydrogen and sulfur.

  18. Mercury removal sorbents

    Science.gov (United States)

    Alptekin, Gokhan

    2016-03-29

    Sorbents and methods of using them for removing mercury from flue gases over a wide range of temperatures are disclosed. Sorbent materials of this invention comprise oxy- or hydroxyl-halogen (chlorides and bromides) of manganese, copper and calcium as the active phase for Hg.sup.0 oxidation, and are dispersed on a high surface porous supports. In addition to the powder activated carbons (PACs), this support material can be comprised of commercial ceramic supports such as silica (SiO.sub.2), alumina (Al.sub.2O.sub.3), zeolites and clays. The support material may also comprise of oxides of various metals such as iron, manganese, and calcium. The non-carbon sorbents of the invention can be easily injected into the flue gas and recovered in the Particulate Control Device (PCD) along with the fly ash without altering the properties of the by-product fly ash enabling its use as a cement additive. Sorbent materials of this invention effectively remove both elemental and oxidized forms of mercury from flue gases and can be used at elevated temperatures. The sorbent combines an oxidation catalyst and a sorbent in the same particle to both oxidize the mercury and then immobilize it.

  19. Use of biogenic sulfide for ZnS precipitation

    NARCIS (Netherlands)

    Esposito, G.; Veeken, A.; Weijma, J.; Lens, P.N.L.

    2006-01-01

    A 600 ml continuously stirred tank reactor was used to assess the performance of a zinc sulfide precipitation process using a biogenic sulfide solution (the effluent of a sulfate-reducing bioreactor) as sulfide source. In all experiments, a proportional-integral (PI) control algorithm was used to

  20. A physiologically based kinetic model for bacterial sulfide oxidation

    NARCIS (Netherlands)

    Klok, J.B.M.; Graaff, de C.M.; Bosch, van den P.L.F.; Boelee, N.C.; Keesman, K.J.; Janssen, A.J.H.

    2013-01-01

    In the biotechnological process for hydrogen sulfide removal from gas streams, a variety of oxidation products can be formed. Under natron-alkaline conditions, sulfide is oxidized by haloalkaliphilic sulfide oxidizing bacteria via flavocytochrome c oxidoreductase. From previous studies, it was

  1. 40 CFR 425.03 - Sulfide analytical methods and applicability.

    Science.gov (United States)

    2010-07-01

    ... § 425.03 Sulfide analytical methods and applicability. (a) The potassium ferricyanide titration method... ferricyanide titration method for the determination of sulfide in wastewaters discharged by plants operating in... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Sulfide analytical methods and...

  2. Mercury's Magnetic Field

    Science.gov (United States)

    Johnson, C. L.

    2014-12-01

    Mercury is the only inner solar system body other than Earth to possess an active core dynamo-driven magnetic field and the only planet with a small, highly dynamic magnetosphere. Measurements made by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft have provided a wealth of data on Mercury's magnetic field environment. Mercury's weak magnetic field was discovered 40 years ago by the Mariner 10 spacecraft, but its large-scale geometry, strength and origin could not be definitively established. MESSENGER data have shown that the field is dynamo-generated and can be described as an offset axisymmetric dipole field (hereafter OAD): the magnetic equator lies ~0.2 RM (RM = 2440 km) north of the geographic equator and the dipole moment is 2.8 x1019 Am2 (~0.03% that of Earth's). The weak internal field and the high, but variable, solar wind ram pressure drive vigorous magnetospheric dynamics and result in an average distance from the planet center to the sub-solar magnetopause of only 1.42 RM. Magnetospheric models developed with MESSENGER data have allowed re-analysis of the Mariner 10 observations, establishing that there has been no measureable secular variation in the internal field over 40 years. Together with spatial power spectra for the OAD, this provides critical constraints for viable dynamo models. Time-varying magnetopause fields induce secondary core fields, the magnitudes of which confirm the core radius estimated from MESSENGER gravity and Earth-based radar data. After accounting for large-scale magnetospheric fields, residual signatures are dominated by additional external fields that are organized in the local time frame and that vary with magnetospheric activity. Birkeland currents have been identified, which likely close in the planetary interior at depths below the base of the crust. Near-periapsis magnetic field measurements at altitudes greater than 200 km have tantalizing hints of crustal fields, but crustal

  3. Sediment-water interactions affecting dissolved-mercury distributions in Camp Far West Reservoir, California

    Science.gov (United States)

    Kuwabara, James S.; Alpers, Charles N.; Marvin-DiPasquale, Mark; Topping, Brent R.; Carter, James L.; Stewart, A. Robin; Fend, Steven V.; Parcheso, Francis; Moon, Gerald E.; Krabbenhoft, David P.

    2003-01-01

    Field and laboratory studies were conducted in April and November 2002 to provide the first direct measurements of the benthic flux of dissolved (0.2-micrometer filtered) mercury species (total and methylated forms) between the bottom sediment and water column at three sampling locations within Camp Far West Reservoir, California: one near the Bear River inlet to the reservoir, a second at a mid-reservoir site of comparable depth to the inlet site, and the third at the deepest position in the reservoir near the dam (herein referred to as the inlet, midreservoir and near-dam sites, respectively; Background, Fig. 1). Because of interest in the effects of historic hydraulic mining and ore processing in the Sierra Nevada foothills just upstream of the reservoir, dissolved-mercury species and predominant ligands that often control the mercury speciation (represented by dissolved organic carbon, and sulfides) were the solutes of primary interest. Benthic flux, sometimes referred to as internal recycling, represents the transport of dissolved chemical species between the water column and the underlying sediment. Because of the affinity of mercury to adsorb onto particle surfaces and to form insoluble precipitates (particularly with sulfides), the mass transport of mercury in mining-affected watersheds is typically particle dominated. As these enriched particles accumulate at depositional sites such as reservoirs, benthic processes facilitate the repartitioning, transformation, and transport of mercury in dissolved, biologically reactive forms (dissolved methylmercury being the most bioavailable for trophic transfer). These are the forms of mercury examined in this study. In contrast to typical scientific manuscripts, this report is formatted in a pyramid-like structure to serve the needs of diverse groups who may be interested in reviewing or acquiring information at various levels of technical detail (Appendix 1). The report enables quick transitions between the initial

  4. Possibilities of mercury removal in the dry flue gas cleaning lines of solid waste incineration units.

    Science.gov (United States)

    Svoboda, Karel; Hartman, Miloslav; Šyc, Michal; Pohořelý, Michael; Kameníková, Petra; Jeremiáš, Michal; Durda, Tomáš

    2016-01-15

    Dry methods of the flue gas cleaning (for HCl and SO2 removal) are useful particularly in smaller solid waste incineration units. The amount and forms of mercury emissions depend on waste (fuel) composition, content of mercury and chlorine and on the entire process of the flue gas cleaning. In the case of high HCl/total Hg molar ratio in the flue gas, the majority (usually 70-90%) of mercury is present in the form of HgCl2 and a smaller amount in the form of mercury vapors at higher temperatures. Removal of both main forms of mercury from the flue gas is dependent on chemical reactions and sorption processes at the temperatures below approx. 340 °C. Significant part of HgCl2 and a small part of elemental Hg vapors can be adsorbed on fly ash and solid particle in the air pollution control (APC) processes, which are removed in dust filters. Injection of non-impregnated active carbon (AC) or activated lignite coke particles is able to remove mainly the oxidized Hg(2+) compounds. Vapors of metallic Hg(o) are adsorbed relatively weakly. Much better chemisorption of Hg(o) together with higher sorbent capacity is achieved by AC-based sorbents impregnated with sulfur, alkali poly-sulfides, ferric chloride, etc. Inorganic sorbents with the same or similar chemical impregnation are also applicable for deeper Hg(o) removal (over 85%). SCR catalysts convert part of Hg(o) into oxidized compounds (HgO, HgCl2, etc.) contributing to more efficient Hg removal, but excess of NH3 has a negative effect. Both forms, elemental Hg(o) and HgCl2, can be converted into HgS particles by reacting with droplets/aerosol of poly-sulfides solutions/solids in flue gas. Mercury captured in the form of water insoluble HgS is more advantageous in the disposal of solid waste from APC processes. Four selected options of the dry flue gas cleaning with mercury removal are analyzed, assessed and compared (in terms of efficiency of Hg-emission reduction and costs) with wet methods and retrofits for more

  5. Oxygen Depletion on the Surface of Mercury: Evidence of Silicon Smelting?

    Science.gov (United States)

    McCubbin, F. M.; Vander Kaaden, K. E.; Peplowski, P. N.; Bell, A. S.; Evans, L. G.; Nittler, L. R.; Boyce, J. W.; Keller, L. P.; McCoy, T. J.

    2017-01-01

    The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft collected data that provided important insights into the structure, chemical makeup, and compositional diversity of Mercury. The X-Ray Spectrometer (XRS) and Gamma-Ray Spectrometer (GRS) onboard MESSENGER provided the first detailed chemical analyses of Mercury's surface. Among the many discoveries included several surprising characteristics about the surface of Mercury, including elevated S abundances (up to 4 percent by weight), low Fe abundances (less than 4 percent by weight), and relatively low O abundances (O/Si ratio of 1.40 plus or minus 0.03). The surface chemistry as determined by MESSENGER has been used to identify up to nine distinct geochemical terranes on Mercury. Numerous modeling and experimental efforts have been undertaken to infer the mineralogy and petrology of mercurian lavas and surface materials. However, all of these efforts have presumed valence states for each of the elements according to the following: Si4+, Ti4+, Al3+, Cr2+, Fe2+, Mn2+, Mg2+, Ca2+, Na+, K+, S2-, Cl-. Based on these valence assignments, cations are charged balanced with the anions O2-, S2-, and Cl- and the compositions are recast in terms of oxides, sulfides, and chlorides. Based on these assumptions, the geochemical terranes that have been identified on Mercury yield O/Si wt. ratios ranging from 1.61 to 1.84, which is substantially higher than the preliminary O/Si ratio of 1.40 plus or minus 0.03 determined by the MESSENGER GRS]. We have re-evaluated the O/Si ratio using the entire MESSENGER dataset to reassess its implications for the geochemistry of Mercury.

  6. Microaeration reduces hydrogen sulfide in biogas

    Science.gov (United States)

    Although there are a variety of biological and chemical treatments for removal of hydrogen sulfide (H2S) from biogas, all require some level of chemical or water inputs and maintenance. In practice, managing biogas H2S remains a significant challenge for agricultural digesters where labor and opera...

  7. REACTION PROCESSES OF ARSENIC IN SULFIDIC SOLUTIONS

    Science.gov (United States)

    The fate of arsenic in the environment is fundamentally linked to its speciation. Arsenic in aerobic environments is predominantly arsenate, however under reducing conditions arsenite species dominate. In anoxic or sulfidic environments thioarsenite ((As(OH)x(SH)yz-) species alon...

  8. Microbial Fuel Cells for Sulfide Removal

    NARCIS (Netherlands)

    Rabaey, K.; Sompel, van de S.; Maignien, L.; Boon, N.; Aelterman, P.; Clauwaert, P.; Schamphelaire, de L.; The Pham, H.; Vermeulen, J.; Verhaege, M.; Lens, P.N.L.; Verstraete, W.

    2006-01-01

    Thus far, microbial fuel cells (MFCs) have been used to convert carbon-based substrates to electricity. However, sulfur compounds are ubiquitously present in organic waste and wastewater. In this study, a MFC with a hexacyanoferrate cathodic electrolyte was used to convert dissolved sulfide to

  9. Support Effect in Hydrodesulfurization over Ruthenium Sulfide

    Czech Academy of Sciences Publication Activity Database

    Gulková, Daniela; Kaluža, Luděk; Vít, Zdeněk; Zdražil, Miroslav

    2009-01-01

    Roč. 51, č. 2 (2009), s. 146-149 ISSN 1337-7027 R&D Projects: GA ČR GA104/06/0705 Institutional research plan: CEZ:AV0Z40720504 Keywords : ruthenium sulfide * hydrodesulfurization * support effect Subject RIV: CC - Organic Chemistry

  10. Mitochondrial Sulfide Quinone Oxidoreductase Prevents Activation of the Unfolded Protein Response in Hydrogen Sulfide*

    OpenAIRE

    Horsman, Joseph W.; Miller, Dana L.

    2015-01-01

    Hydrogen sulfide (H2S) is an endogenously produced gaseous molecule with important roles in cellular signaling. In mammals, exogenous H2S improves survival of ischemia/reperfusion. We have previously shown that exposure to H2S increases the lifespan and thermotolerance in Caenorhabditis elegans, and improves protein homeostasis in low oxygen. The mitochondrial SQRD-1 (sulfide quinone oxidoreductase) protein is a highly conserved enzyme involved in H2S metabolism. SQRD-1 is generally considere...

  11. Mercury: Exploration of a Planet

    Science.gov (United States)

    1976-01-01

    The flight of the Mariner 10 spacecraft to Venus and Mercury is detailed in animation and photography. Views of Mercury are featured. Also included is animation on the origin of the solar system. Dr. Bruce C. Murray, director of the Jet Propulsion Laboratory, comments on the mission.

  12. Rotation of the planet mercury.

    Science.gov (United States)

    Jefferys, W H

    1966-04-08

    The equations of motion for the rotation of Mercury are solved for the general case by an asymptotic expansion. The findings of Liu and O'Keefe, obtained by numerical integration of a special case, that it is possible for Mercury's rotation to be locked into a 2:3 resonance with its revolution, are confirmed in detail. The general solution has further applications.

  13. Bioavailability of mercury in contaminated Oak Ridge watershed and potential remediation of river/runoff/storm water by an aquatic plant - 16319

    International Nuclear Information System (INIS)

    Su, Yi; Han, Fengxiang X.; Chen, Jian; Xia, Yunju; Monts, David L.

    2009-01-01

    Historically as part of its national security mission, the U.S. Department of Energy's Y-12 National Security Facility in Oak Ridge, TN, USA acquired a significant fraction of the world's supply of elemental mercury. During the 1950's and 1960's, a large amount of elemental mercury escaped confinement and is still present in the buildings and grounds of the Y-12 Facility and in the Y-12 Watershed. Because of the adverse effects of elemental mercury and mercury compounds upon human health, the Oak Ridge Site is engaged in an on-going effort to monitor and remediate the area. The main thrust of the Oak Ridge mercury remediation effort is currently scheduled for implementation in FY09. In order to more cost effectively implement those extensive remediation efforts, it is necessary now to obtain an improved understanding of the role that mercury and mercury compounds play in the Oak Ridge ecosystem. Most recently, concentrations of both total mercury and methylmercury in fish and water of lower East Fork Poplar Creek (LEFPC) of Oak Ridge increased although the majority of mercury in the site is mercury sulfide. This drives the US DOE and the Oak Ridge Site to study the long-term bioavailability of mercury and speciation at the site. The stability and bioavailability of mercury sulfide as affected by various biogeochemical conditions -presence of iron oxides have been studied. We examined the kinetic rate of dissolution of cinnabar from Oak Ridge soils and possible mechanisms and pathways in triggering the most recent increase of mercury solubility, bioavailability and mobility in Oak Ridge site. The effects of pH and chlorine on oxidative dissolution of cinnabar from cinnabar-contaminated Oak Ridge soils is discussed. On the other hand, aquatic plants might be good candidate for phyto-remediate contaminated waste water and phyto-filtration of collective storm water and surface runoff and river. Our greenhouse studies on uptake of Hg by water lettuce (Pistia stratiotes

  14. Platinum and Palladium Exsolution Textures in Quenched Sulfide Melts

    Science.gov (United States)

    Reo, G.; Frank, M. R.; Loocke, M. P.; Macey, C. J.

    2017-12-01

    Magmatic sulfide ore deposits account for over 80% of the world's platinum group element (PGE) reserves. Layered mafic intrusions (LMIs), a type of magmatic sulfide ore deposit, contain alternating layers of silicate and sulfide mineralization that are thought to have coexisted as an immiscible silicate + sulfide melt pair. Platinum and palladium, the most common PGEs found in LMIs, heavily favor the sulfide melt. Nernst partition coefficients for Pt (D = wt% of Pt in sulfide/wt% of Pt in silicate) range from 102 to 109. This study examined the Pt- and Pd-bearing phases that formed from the quenched sulfide melts to better constrain the PGE-rich sulfide layers of LMIs system. Experiments were conducted with a basalt melt, sulfide melt, and Pt-Pd metal in a vertical tube furnace at 1100°C and 1 atm and with oxygen fugacity buffered to QFM (quartz-fayalite-magnetite). Following the experiments, run products containing both sulfide and silicate glasses (quenched melts) were analyzed by a Shimadzu EPMA-1720HT Electron Probe Microanalyzer. The focus here is on the quenched Fe-rich sulfides whereas data on the partitioning of Pt and Pd between the coexisting silicate and sulfide melts will be presented in the future. The sulfide samples were imaged in back-scattering mode and major and trace element concentrations of separate metal-rich phases in the sulfide matrix were ascertained through wavelength-dispersive x-ray spectroscopy. Three discernable PGE-rich phases were found to have exsolved from the sulfide matrix upon quenching of the sulfide melt. All of these phases had Fe and S of 21-24 and 16-22 wt.%, respectively. An irregularly shaped Pd- and Cu-rich sulfide phase ( 36 and 14 wt.%, respectively) makes up the majority of the exsolution product. A separate Pd- and Ni-rich phase ( 22 and 14 wt%, respectively) can be found as grains or rims adjacent to the exsolved Pd- and Cu-rich phase. A third Pd- and Pt-rich phase ( 26 and 18 wt.%, respectively) exhibits a

  15. 49 CFR 173.164 - Mercury (metallic and articles containing mercury).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Mercury (metallic and articles containing mercury... Than Class 1 and Class 7 § 173.164 Mercury (metallic and articles containing mercury). (a) For transportation by aircraft, mercury must be packaged in packagings which meet the requirements of part 178 of...

  16. Chronic mercury exposure in Late Neolithic/Chalcolithic populations in Portugal from the cultural use of cinnabar

    Science.gov (United States)

    Emslie, Steven D.; Brasso, Rebecka; Patterson, William P.; Carlos Valera, António; McKenzie, Ashley; Maria Silva, Ana; Gleason, James D.; Blum, Joel D.

    2015-10-01

    Cinnabar is a natural mercury sulfide (HgS) mineral of volcanic or hydrothermal origin that is found worldwide. It has been mined prehistorically and historically in China, Japan, Europe, and the Americas to extract metallic mercury (Hg0) for use in metallurgy, as a medicinal, a preservative, and as a red pigment for body paint and ceramics. Processing cinnabar via combustion releases Hg0 vapor that can be toxic if inhaled. Mercury from cinnabar can also be absorbed through the gut and skin, where it can accumulate in organs and bone. Here, we report moderate to high levels of total mercury (THg) in human bone from three Late Neolithic/Chalcolithic (5400-4100 B.P.) sites in southern Portugal that were likely caused by cultural use of cinnabar. We use light stable isotope and Hg stable isotope tracking to test three hypotheses on the origin of mercury in this prehistoric human bone. We traced Hg in two individuals to cinnabar deposits near Almadén, Spain, and conclude that use of this mineral likely caused mild to severe mercury poisoning in the prehistoric population. Our methods have applications to bioarchaeological investigations worldwide, and for tracking trade routes and mobility of prehistoric populations where cinnabar use is documented.

  17. Mercury concentration in bivalve molluscs

    Directory of Open Access Journals (Sweden)

    Szkoda Józef

    2015-09-01

    Full Text Available A total of 85 mussel samples of eight species were examined. Analysis of mercury in the freeze-dried samples was carried out by atomic absorption spectrometry method using direct mercury analyser AMA 254. The analytical procedure for determination of mercury was covered by the quality assurance programme of research and participation in national and international proficiency tests. Concentrations of total mercury in all investigated samples were found to be generally low, in the range of 0.033-0.577 mg/kg of dry weight and of 0.003-0.045 mg/kg of wet weight. The results indicate that obtained levels of mercury in bivalve molluscs are not likely to pose a risk to the health of consumers.

  18. Mercury: Beethoven Quadrangle, H-7

    Science.gov (United States)

    2000-01-01

    Mercury: Computer Photomosaic of the Beethoven Quadrangle, H-7 The Beethoven Quadrangle, named for the 19th century classical German composer, lies in Mercury's Equatorial Mercator located between longitude 740 to 1440. The Mariner 10 spacecraft imaged the region during its initial flyby of the planet. The Image Processing Lab at NASA's Jet Propulsion Laboratory produced this photomosaic using computer software and techniques developed for use in processing planetary data. The images used to construct the Beethoven Quadrangle were taken as Mariner 10 flew passed Mercury. The Mariner 10 spacecraft was launched in 1974. The spacecraft took images of Venus in February 1974 on the way to three encounters with Mercury in March and September 1974 and March 1975. The spacecraft took more than 7,000 images of Mercury, Venus, the Earth and the Moon during its mission. The Mariner 10 Mission was managed by the Jet Propulsion Laboratory for NASA's Office of Space Science in Washington, D.C.

  19. Human Exposure and Health Effects of Inorganic and Elemental Mercury

    OpenAIRE

    Park, Jung-Duck; Zheng, Wei

    2012-01-01

    Mercury is a toxic and non-essential metal in the human body. Mercury is ubiquitously distributed in the environment, present in natural products, and exists extensively in items encountered in daily life. There are three forms of mercury, i.e., elemental (or metallic) mercury, inorganic mercury compounds, and organic mercury compounds. This review examines the toxicity of elemental mercury and inorganic mercury compounds. Inorganic mercury compounds are water soluble with a bioavailability o...

  20. Methods for dispensing mercury into devices

    Science.gov (United States)

    Grossman, Mark W.; George, William A.

    1987-04-28

    A process for dispensing mercury into devices which requires mercury. Mercury is first electrolytically separated from either HgO or Hg.sub.2 Cl.sub.2 and plated onto a cathode wire. The cathode wire is then placed into a device requiring mercury.

  1. 21 CFR 872.3700 - Dental mercury.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental mercury. 872.3700 Section 872.3700 Food and... DENTAL DEVICES Prosthetic Devices § 872.3700 Dental mercury. (a) Identification. Dental mercury is a device composed of mercury intended for use as a component of amalgam alloy in the restoration of a...

  2. Oxidation and Precipitation of Sulfide in Sewer Networks

    DEFF Research Database (Denmark)

    Nielsen, A. H.

    (Fe(II)) and precipitated subsequently with dissolved sulfide as ferrous sulfide (FeS). The ferrous sulfide precipitation was relatively fast, but not immediate. Despite the very low solubility of ferrous sulfide, initially present iron did not react completely with sulfide. This observation...... were studied in both wastewater and biofilms. Particular emphasis was on the importance of iron in the sulfur cycle. Iron is typically among the dominant metals in wastewater. The experiments showed that, ferric iron (Fe(III)) that was added to anaerobic wastewater was rapidly reduced to ferrous iron...... was probably explained by the presence of ligands in the wastewater, which reacted with the iron. The biofilm experiments showed that sulfide accumulated along with several metals in anaerobic biofilms as the result of metal sulfide precipitation. Particularly, zinc and cupper were important...

  3. Electrochemical Synthesis and Characterization of Zinc Sulfide Nanoparticles

    Directory of Open Access Journals (Sweden)

    M. Rahimi-Nasarabadi

    2014-04-01

    Full Text Available Electrosynthesis process has been used for preparation of zinc sulfide nanoparticles. Zinc sulfide nanoparticles in different size and shapes were electrodeposited by electrolysis of zinc plate as anode in sodium sulfide solution. Effects of several reaction variables, such as electrolysis voltage, sulfide ion concentration as reactant, stirring rate of electrolyte solution and temperature on particle size of prepared zinc sulfide were investigated. The significance of these parameters in tuning the size of zinc sulfide particles was quantitatively evaluated by analysis of variance (ANOVA. Also, optimum conditions for synthesis of zinc sulfide nanoparticles via electrosynthesis reaction were proposed. The structure and composition of prepared nanoparticles under optimum condition was characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and UV-Vis spectrophotometry techniques.

  4. Fluorescent sensor for mercury

    Science.gov (United States)

    Wang, Zidong [Urbana, IL; Lee, Jung Heon [Evanston, IL; Lu, Yi [Champaign, IL

    2011-11-22

    The present invention provides a sensor for detecting mercury, comprising: a first polynucleotide, comprising a first region, and a second region, a second polynucleotide, a third polynucleotide, a fluorophore, and a quencher, wherein the third polynucleotide is optionally linked to the second region; the fluorophore is linked to the first polynucleotide and the quencher is linked to the second polynucleotide, or the fluorophore is linked to the second polynucleotide and the quencher is linked to the first polynucleotide; the first region and the second region hybridize to the second polynucleotide; and the second region binds to the third polynucleotide in the presence of Hg.sup.2+ ions.

  5. Increased mercury emissions from modern dental amalgams

    OpenAIRE

    Bengtsson, Ulf G.; Hylander, Lars D.

    2017-01-01

    All types of dental amalgams contain mercury, which partly is emitted as mercury vapor. All types of dental amalgams corrode after being placed in the oral cavity. Modern high copper amalgams exhibit two new traits of increased instability. Firstly, when subjected to wear/polishing, droplets rich in mercury are formed on the surface, showing that mercury is not being strongly bonded to the base or alloy metals. Secondly, high copper amalgams emit substantially larger amounts of mercury vapor ...

  6. The Hydrothermal Chemistry of Gold, Arsenic, Antimony, Mercury and Silver

    Energy Technology Data Exchange (ETDEWEB)

    Bessinger, Brad; Apps, John A.

    2003-03-23

    A comprehensive thermodynamic database based on the Helgeson-Kirkham-Flowers (HKF) equation of state was developed for metal complexes in hydrothermal systems. Because this equation of state has been shown to accurately predict standard partial molal thermodynamic properties of aqueous species at elevated temperatures and pressures, this study provides the necessary foundation for future exploration into transport and depositional processes in polymetallic ore deposits. The HKF equation of state parameters for gold, arsenic, antimony, mercury, and silver sulfide and hydroxide complexes were derived from experimental equilibrium constants using nonlinear regression calculations. In order to ensure that the resulting parameters were internally consistent, those experiments utilizing incompatible thermodynamic data were re-speciated prior to regression. Because new experimental studies were used to revise the HKF parameters for H2S0 and HS-1, those metal complexes for which HKF parameters had been previously derived were also updated. It was found that predicted thermodynamic properties of metal complexes are consistent with linear correlations between standard partial molal thermodynamic properties. This result allowed assessment of several complexes for which experimental data necessary to perform regression calculations was limited. Oxygen fugacity-temperature diagrams were calculated to illustrate how thermodynamic data improves our understanding of depositional processes. Predicted thermodynamic properties were used to investigate metal transport in Carlin-type gold deposits. Assuming a linear relationship between temperature and pressure, metals are predicted to predominantly be transported as sulfide complexes at a total aqueous sulfur concentration of 0.05 m. Also, the presence of arsenic and antimony mineral phases in the deposits are shown to restrict mineralization within a limited range of chemical conditions. Finally, at a lesser aqueous sulfur

  7. Mercury kinetics in marine zooplankton

    International Nuclear Information System (INIS)

    Fowler, S.W.; Heyraud, M.; LaRosa, J.

    1976-01-01

    Mercury, like many other heavy metals, is potentially available to marine animals by uptake directly from water and/or through the organisms food. Furthermore, bioavailability, assimilation and subsequent retention in biota may be affected by the chemical species of the element in sea water. While mercury is known to exist in the inorganic form in sea water, recent work has indicated that, in certain coastal areas, a good portion of the total mercury appears to be organically bound; however, the exact chemical nature of the organic fraction has yet to be determined. Methyl mercury may be one constituent of the natural organically bound fraction since microbial mechanisms for in situ methylation of mercury have been demonstrated in the aquatic environment. Despite the fact that naturally produced methyl mercury probably comprises only a small fraction of an aquatic ecosystem, the well-documented toxic effects of this organo-mercurial, caused by man-made introductions into marine food chains, make it an important compound to study

  8. Atmospheric mercury footprints of nations.

    Science.gov (United States)

    Liang, Sai; Wang, Yafei; Cinnirella, Sergio; Pirrone, Nicola

    2015-03-17

    The Minamata Convention was established to protect humans and the natural environment from the adverse effects of mercury emissions. A cogent assessment of mercury emissions is required to help implement the Minamata Convention. Here, we use an environmentally extended multi-regional input-output model to calculate atmospheric mercury footprints of nations based on upstream production (meaning direct emissions from the production activities of a nation), downstream production (meaning both direct and indirect emissions caused by the production activities of a nation), and consumption (meaning both direct and indirect emissions caused by final consumption of goods and services in a nation). Results show that nations function differently within global supply chains. Developed nations usually have larger consumption-based emissions than up- and downstream production-based emissions. India, South Korea, and Taiwan have larger downstream production-based emissions than their upstream production- and consumption-based emissions. Developed nations (e.g., United States, Japan, and Germany) are in part responsible for mercury emissions of developing nations (e.g., China, India, and Indonesia). Our findings indicate that global mercury abatement should focus on multiple stages of global supply chains. We propose three initiatives for global mercury abatement, comprising the establishment of mercury control technologies of upstream producers, productivity improvement of downstream producers, and behavior optimization of final consumers.

  9. Method for removal and stabilization of mercury in mercury-containing gas streams

    Science.gov (United States)

    Broderick, Thomas E.

    2005-09-13

    The present invention is directed to a process and apparatus for removing and stabilizing mercury from mercury-containing gas streams. A gas stream containing vapor phase elemental and/or speciated mercury is contacted with reagent, such as an oxygen-containing oxidant, in a liquid environment to form a mercury-containing precipitate. The mercury-containing precipitate is kept or placed in solution and reacts with one or more additional reagents to form a solid, stable mercury-containing compound.

  10. Cysteine Addition Promotes Sulfide Production and 4-Fold Hg(II)-S Coordination in Actively Metabolizing Escherichia coli.

    Science.gov (United States)

    Thomas, Sara A; Gaillard, Jean-François

    2017-04-18

    The bacterial uptake of mercury(II), Hg(II), is believed to be energy-dependent and is enhanced by cysteine in diverse species of bacteria under aerobic and anaerobic conditions. To gain insight into this Hg(II) biouptake pathway, we have employed X-ray absorption spectroscopy (XAS) to investigate the relationship between exogenous cysteine, cellular metabolism, cellular localization, and Hg(II) coordination in aerobically respiring Escherichia coli (E. coli). We show that cells harvested in exponential growth phase consistently display mixtures of 2-fold and 4-fold Hg(II) coordination to sulfur (Hg-S 2 and Hg-S 4 ), with added cysteine enhancing Hg-S 4 formation. In contrast, cells in stationary growth phase or cells treated with a protonophore causing a decrease in cellular ATP predominantly contain Hg-S 2 , regardless of cysteine addition. Our XAS results favor metacinnabar (β-HgS) as the Hg-S 4 species, which we show is associated with both the cell envelope and cytoplasm. Additionally, we observe that added cysteine abiotically oxidizes to cystine and exponentially growing E. coli degrade high cysteine concentrations (100-1000 μM) into sulfide. Thermodynamic calculations confirm that cysteine-induced sulfide biosynthesis can promote the formation of dissolved and particulate Hg(II)-sulfide species. This report reveals new complexities arising in Hg(II) bioassays with cysteine and emphasizes the need for considering changes in chemical speciation as well as growth stage.

  11. Sulfurization of Dissolved Organic Matter Increases Hg-Sulfide-Dissolved Organic Matter Bioavailability to a Hg-Methylating Bacterium.

    Science.gov (United States)

    Graham, Andrew M; Cameron-Burr, Keaton T; Hajic, Hayley A; Lee, Connie; Msekela, Deborah; Gilmour, Cynthia C

    2017-08-15

    Reactions of dissolved organic matter (DOM) with aqueous sulfide (termed sulfurization) in anoxic environments can substantially increase DOM's reduced sulfur functional group content. Sulfurization may affect DOM-trace metal interactions, including complexation and metal-containing particle precipitation, aggregation, and dissolution. Using a diverse suite of DOM samples, we found that susceptibility to additional sulfur incorporation via reaction with aqueous sulfide increased with increasing DOM aromatic-, carbonyl-, and carboxyl-C content. The role of DOM sulfurization in enhancing Hg bioavailability for microbial methylation was evaluated under conditions typical of Hg methylation environments (μM sulfide concentrations and low Hg-to-DOM molar ratios). Under the conditions of predicted metacinnabar supersaturation, microbial Hg methylation increased with increasing DOM sulfurization, likely reflecting either effective inhibition of metacinnabar growth and aggregation or the formation of Hg(II)-DOM thiol complexes with high bioavailability. Remarkably, Hg methylation efficiencies with the most sulfurized DOM samples were similar (>85% of total Hg methylated) to that observed in the presence of l-cysteine, a ligand facilitating rapid Hg(II) biouptake and methylation. This suggests that complexes of Hg(II) with DOM thiols have similar bioavailability to Hg(II) complexes with low-molecular-weight thiols. Overall, our results are a demonstration of the importance of DOM sulfurization to trace metal and metalloid (especially mercury) fate in the environment. DOM sulfurization likely represents another link between anthropogenic sulfate enrichment and MeHg production in the environment.

  12. Exploring Mercury: The Iron Planet

    OpenAIRE

    Stevenson, David J.

    2004-01-01

    Planet Mercury is both difficult to observe and difficult to reach by spacecraft. Just one spacecraft, Mariner 10, flew by the planet 30 years ago. An upcoming NASA mission, MESSENGER, will be launched this year and will go into orbit around Mercury at the end of this decade. A European mission is planned for the following decade. It's worth going there because Mercury is a strange body and the history of planetary exploration has taught us that strangeness gives us insight into planetary ori...

  13. MESSENGER'S First Flyby of Mercury

    Science.gov (United States)

    Slavin, James A.

    2008-01-01

    The MESSENGER mission to Mercury offers our first opportunity to explore this planet's miniature magnetosphere since Mariner 10's brief fly-bys in 1974-5. The magnetosphere of Mercury is the smallest in the solar system with its magnetic field typically standing off the solar wind only - 1000 to 2000 km above the surface. An overview of the MESSENGER mission and its January 14th close flyby of Mercury will be provided. Primary science objectives and the science instrumentation will be described. Initial results from MESSENGER'S first flyby on January 14th, 2008 will be discussed with an emphasis on the magnetic field and charged particle measurements.

  14. Cadmium zinc sulfide by solution growth

    Science.gov (United States)

    Chen, Wen S.

    1992-05-12

    A process for depositing thin layers of a II-VI compound cadmium zinc sulfide (CdZnS) by an aqueous solution growth technique with quality suitable for high efficiency photovoltaic or other devices which can benefit from the band edge shift resulting from the inclusion of Zn in the sulfide. A first solution comprising CdCl.sub.2 2.5H.sub.2 O, NH.sub.4 Cl, NH.sub.4 OH and ZnCl.sub.2, and a second solution comprising thiourea ((NH.sub.2).sub.2 CS) are combined and placed in a deposition cell, along with a substrate to form a thin i.e. 10 nm film of CdZnS on the substrate. This process can be sequentially repeated with to achieve deposition of independent multiple layers having different Zn concentrations.

  15. Iron-sulfide redox flow batteries

    Science.gov (United States)

    Xia, Guan-Guang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2013-12-17

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  16. Oxidation of Reduced Sulfur Species: Carbonyl Sulfide

    DEFF Research Database (Denmark)

    Glarborg, Peter; Marshall, Paul

    2013-01-01

    A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts satisfact......A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts...... satisfactorily oxidation of OCS over a wide range of stoichiometric air–fuel ratios (0.5 ≤λ≤7.3), temperatures (450–1700 K), and pressures (0.02–3.0 atm) under dry conditions. The governing reaction mechanisms are outlined based on calculations with the kinetic model. The oxidation rate of OCS is controlled...

  17. Layered metal sulfides capture uranium from seawater.

    Science.gov (United States)

    Manos, Manolis J; Kanatzidis, Mercouri G

    2012-10-03

    Uranium is the main source for nuclear energy but also one of the most toxic heavy metals. The current methods for uranium removal from water present limitations, such as narrow pH operating range, limited tolerance to high salt concentrations, or/and high cost. We show here that a layered sulfide ion exchanger K(2)MnSn(2)S(6) (KMS-1) overcomes these limitations and is exceptionally capable in selectively and rapidly sequestering high (ppm) as well as trace (ppb) quantities of UO(2)(2+) under a variety of conditions, including seawater. KMS-1 can efficiently absorb the naturally occurring U traces in seawater samples. The results presented here reveal the exceptional potential of sulfide-based ion-exchangers for remediating of uranium-containing wastes and groundwater and for extracting uranium from the sea.

  18. Ferrocene sulfonates as electrocatalysts for sulfide detection

    International Nuclear Information System (INIS)

    Lawrence, Nathan S.; Tustin, Gary J.; Faulkner, Michael; Jones, Timothy G.J.

    2006-01-01

    The electrochemical characterization of both the mono- and di-substituted forms of ferrocene sulfonate are given. The results show both species produce voltammograms consistent with quasi-irreversible diffusion controlled redox reactions. The FcSO 3 - species was found to be easier to oxidize than its Fc(SO 3 ) 2 2- counterpart, due to the electron withdrawing affect of the sulfonate group on the Fe centre. In the presence of sulfide, the voltammetric response of FcSO 3 - is shown to be consistent with the occurrence of an electrocatalytic EC' reaction. This analytical response was utilized as a means of determining sulfide and was found to be linear over the concentration 0.02-1 mM with a limit of detection of 14 μM

  19. Distribution and retention of organic and inorganic mercury in methyl mercury-treated neonatal rats

    International Nuclear Information System (INIS)

    Thomas, D.J.; Fisher, H.L.; Sumler, M.R.; Hall, L.L.; Mushak, P.

    1988-01-01

    Seven-day-old Long Evans rats received one mumol of 203 Hg-labeled methyl mercury/kg sc and whole body retention and tissue distribution of organic and inorganic mercury were examined for 32 days postdosing. Neonates cleared mercury slowly until 10 days postdosing when the clearance rate abruptly increased. During the interval when whole body clearance of mercury was extremely slow, methyl mercury was metabolized to inorganic mercury. Peak concentration of mercury in kidney occurred at 2 days postdosing. At 32 days postdosing, 8% of mercury in kidney was in an organic from. Liver mercury concentration peaked at 2 days postdosing and organic mercury accounted for 38% at 32 days postdosing. Brain concentrations of mercury peaked at 2 days postdosing. At 10 days postdosing, organic mercury accounted for 86% of the brain mercury burden, and, at 32 days postdosing, for 60%. The percentage of mercury body burden in pelt rose from 30 to 70% between 1 and 10 days postdosing. At 32 days postdosing pelt contained 85% of the body burden of mercury. At all time points, about 95% of mercury in pelt was in an organic form. Compartmental analysis of these data permitted development of a model to describe the distribution and excretion of organic and inorganic mercury in methyl mercury-treated neonatal rats

  20. Various communications concerning sulfigran (sodium sulfide)

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, H.; Montfort, F.; Wickert; Horn; Junkermann; Wissel, K.; Pier, M.

    1943-01-01

    Most of these communications concerned the problems experienced by Poelitz when its regular supplier of Sulfigran (sodium sulfide), the I.G. Farbenindustrie plant at Luverkusen, had to shut down for repairs and Poelitz had to get an impure form of Sulfigran mixture (a crude melt of ore) from other suppliers, including the I.G. Farbenindustrie plant at Wolfen (Bitterfeld). Various problems arose in the transition, including the fact that the mixture supplied was not ground finely enough for the coal-paste-preparing machinery at Poelitz to handle without damage. An analysis of one sample of the raw melt mixture gave 68.8% sodium sulfide, 12.0% carbon, 1.5% hydrogen, 1.6% silicon dioxide, 1.8% iron, 1.0% aluminum, 0.6% calcium, traces of magnesium and sulfate, and 15.4% water-insoluble. An analysis for another sample showed about 1.8% less sodium sulfide, 1.5% more silicon dioxide, 0.7% less iron, 0.5% less aluminum, 0.6% more calcium, etc., than the previous analysis. Finally one of the communications was a letter in which Ludwigshafen responded favorably to Poelitz's question about whether it would be advantageous to add Sulfigran directly to the first oven of a hydrogenation chamber instead of grinding it with the coal paste. Ludwigshafen said that in some experiments it had observed deposits at places where Sulfigran and coal paste encountered each other in preheater tubes. The deposits consisted of sodium sulfide and iron compounds. 3 tables.

  1. Hydrogen sulfide prodrugs—a review

    Directory of Open Access Journals (Sweden)

    Yueqin Zheng

    2015-09-01

    Full Text Available Hydrogen sulfide (H2S is recognized as one of three gasotransmitters together with nitric oxide (NO and carbon monoxide (CO. As a signaling molecule, H2S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H2S prodrugs for various reasons. In this review, we summarize different H2S prodrugs, their chemical properties, and some of their potential therapeutic applications.

  2. Single-layer transition metal sulfide catalysts

    Science.gov (United States)

    Thoma, Steven G [Albuquerque, NM

    2011-05-31

    Transition Metal Sulfides (TMS), such as molybdenum disulfide (MoS.sub.2), are the petroleum industry's "workhorse" catalysts for upgrading heavy petroleum feedstocks and removing sulfur, nitrogen and other pollutants from fuels. We have developed an improved synthesis technique to produce SLTMS catalysts, such as molybdenum disulfide, with potentially greater activity and specificity than those currently available. Applications for this technology include heavy feed upgrading, in-situ catalysis, bio-fuel conversion and coal liquefaction.

  3. Sulfide Precipitation in Wastewater at Short Timescales

    DEFF Research Database (Denmark)

    Kiilerich, Bruno; van de Ven, Wilbert; Nielsen, Asbjørn Haaning

    2017-01-01

    that this is not the case for sulfide precipitation by ferric iron. Instead, the reaction time was found to be on a timescale where it must be considered when performing end-of-pipe treatment. For real wastewaters at pH 7, a stoichiometric ratio around 14 mol Fe(II) (mol S(−II))−1 was obtained after 1.5 s, while the ratio...

  4. Recent mercury contamination from artisanal gold mining on Buru Island, Indonesia--potential future risks to environmental health and food safety.

    Science.gov (United States)

    Male, Yusthinus Thobias; Reichelt-Brushett, Amanda Jean; Pocock, Matt; Nanlohy, Albert

    2013-12-15

    In November 2011 gold was found at Mount Botak, Buru Island, Mollucas Province, Indonesia. Since 2012 mercury has been used to extract the gold requiring large volumes of water and resulting in deposition of mercury into Wamsait River and Kayeli Bay. Total mercury in waste ponds was over 680 mg/kg. In sediments at the mouth of the local river and a small feeder creek >3.00 mg/kg and >7.66 mg/kg respectively. River and bay sediments were proportionately higher in available mercury than elemental mercury and more strongly bound mercuric sulfide compared to that in trommel waste. This preliminary investigation raises concerns about the long term distribution and speciation of mercury. The floodplain is an important agricultural resource, and Mollucas Province is recognised nationally as the centre for Indonesian fish stocks. Challenges for management include communicating the potential future risks to the community and leaders and identifying mechanisms to reduce mercury waste. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  5. The effect of mercury deposition to ecosystem around coal-power plants in Tan-An peninsular, S. Korea

    Science.gov (United States)

    Kim, Y.; Lee, J.; Song, K.; Shin, S.; Han, J.; Hong, E.; Jung, G.

    2009-12-01

    According to UNEP’s Report in 2008, Korea is one of the largest mercury emitting country with emission amount of 32 tones and the contribution of stationary coal combustion is estimated around 59%, as one of major mercury emission sources. There are growing needs of ecosystem mercury monitoring to evaluate the effectiveness on mercury emission controls by regulations. Thus, the aim of this study was to identify the useful monitoring indicators by comparing mercury levels of various environmental matrices in different ecosystems. Tae-an coal power plant, located on the west coastal of Korea is selected for study sites since it is one of the largest coal power plant in Korea with 4000 MW capacities. We chose 2 reservoirs near to Tae-an coal power plant and 2 others in An-myeon and Baeg-ryeong island for control study. Total gaseous mercury of ambient air was 3.6, 4.5 and 1.2 ng/m3 for Tae-an, An-myeon and Baeg-ryeong sites, respectively. From these results, we investigated and compared total mercury and methylmercury concentrations in surface water, soil, sediment, leaves and freshwater fish between reservoirs, which were known for the indicators of mercury atmospheric deposition. Estimates for the potential rates of methylation and activities of sulfur reducing bacteria were also made by injection radioactive isotopes of 203Hg and 35S. Potential methylation rate and acid volatile sulfide formation potential were dramatically changed by depth and maximum values were found in the top sediment section.

  6. Elimination of mercury in health care facilities.

    Science.gov (United States)

    2000-03-01

    Mercury is a persistent, bioaccumulative toxin that has been linked to numerous health effects in humans and wildlife. It is a potent neurotoxin that may also harm the brain, kidneys, and lungs. Unborn children and young infants are at particular risk for brain damage from mercury exposure. Hospitals' use of mercury in chemical solutions, thermometers, blood pressure gauges, batteries, and fluorescent lamps makes these facilities large contributors to the overall emission of mercury into the environment. Most hospitals recognize the dangers of mercury. In a recent survey, four out of five hospitals stated that they have policies in place to eliminate the use of mercury-containing products. Sixty-two percent of them require vendors to disclose the presence of mercury in chemicals that the hospitals purchase. Only 12 percent distribute mercury-containing thermometers to new parents. Ninety-two percent teach their employees about the health and environmental effects of mercury, and 46 percent teach all employees how to clean up mercury spills. However, the same study showed that many hospitals have not implemented their policies. Forty-two percent were not aware whether they still purchased items containing mercury. In addition, 49 percent still purchase mercury thermometers, 44 percent purchase mercury gastrointestinal diagnostic equipment, and 64 percent still purchase mercury lab thermometers.

  7. Mercury pollution: a transdisciplinary treatment

    National Research Council Canada - National Science Library

    Zuber, Sharon L; Newman, Michael C

    2012-01-01

    .... Also included are smaller case studies, such as the Minamata tragedy, fish consumption, and international treaties"-- "Mercury is the gravest chemical pollutant problem of our time, and this is...

  8. Origin and composition of Mercury

    International Nuclear Information System (INIS)

    Lewis, J.S.

    1988-01-01

    The predictions of the expected range of composition of Mercury at the time of its formation made on the basis of a suite of condensation-accretion models of Mercury spanning a range of condensation temperature and accretion sampling functions appropriate to Mercury are examined. It is concluded that these compositonal models can, if modified to take into account the nonselective loss of most of the silicate component of the planet during accretion, provide compositional predictions for the Weidenschilling (1978, 1980) mechanism for the accretion of a metal-rich Mercury. The silicate portion would, in this case, contain 3.6 to 4.5 percent alumina, roughly 1 percent of alkali oxides, and between 0.5 and 6 percent FeO

  9. Microaeration for hydrogen sulfide removal in UASB reactor.

    Science.gov (United States)

    Krayzelova, Lucie; Bartacek, Jan; Kolesarova, Nina; Jenicek, Pavel

    2014-11-01

    The removal of hydrogen sulfide from biogas by microaeration was studied in Up-flow Anaerobic Sludge Blanket (UASB) reactors treating synthetic brewery wastewater. A fully anaerobic UASB reactor served as a control while air was dosed into a microaerobic UASB reactor (UMSB). After a year of operation, sulfur balance was described in both reactors. In UASB, sulfur was mainly presented in the effluent as sulfide (49%) and in biogas as hydrogen sulfide (34%). In UMSB, 74% of sulfur was detected in the effluent (41% being sulfide and 33% being elemental sulfur), 10% accumulated in headspace as elemental sulfur and 9% escaped in biogas as hydrogen sulfide. The efficiency of hydrogen sulfide removal in UMSB was on average 73%. Microaeration did not cause any decrease in COD removal or methanogenic activity in UMSB and the elemental sulfur produced by microaeration did not accumulate in granular sludge. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Localized surface plasmon resonance mercury detection system and methods

    Science.gov (United States)

    James, Jay; Lucas, Donald; Crosby, Jeffrey Scott; Koshland, Catherine P.

    2016-03-22

    A mercury detection system that includes a flow cell having a mercury sensor, a light source and a light detector is provided. The mercury sensor includes a transparent substrate and a submonolayer of mercury absorbing nanoparticles, e.g., gold nanoparticles, on a surface of the substrate. Methods of determining whether mercury is present in a sample using the mercury sensors are also provided. The subject mercury detection systems and methods find use in a variety of different applications, including mercury detecting applications.

  11. Mercury Toolset for Spatiotemporal Metadata

    Science.gov (United States)

    Devarakonda, Ranjeet; Palanisamy, Giri; Green, James; Wilson, Bruce; Rhyne, B. Timothy; Lindsley, Chris

    2010-06-01

    Mercury (http://mercury.ornl.gov) is a set of tools for federated harvesting, searching, and retrieving metadata, particularly spatiotemporal metadata. Version 3.0 of the Mercury toolset provides orders of magnitude improvements in search speed, support for additional metadata formats, integration with Google Maps for spatial queries, facetted type search, support for RSS (Really Simple Syndication) delivery of search results, and enhanced customization to meet the needs of the multiple projects that use Mercury. It provides a single portal to very quickly search for data and information contained in disparate data management systems, each of which may use different metadata formats. Mercury harvests metadata and key data from contributing project servers distributed around the world and builds a centralized index. The search interfaces then allow the users to perform a variety of fielded, spatial, and temporal searches across these metadata sources. This centralized repository of metadata with distributed data sources provides extremely fast search results to the user, while allowing data providers to advertise the availability of their data and maintain complete control and ownership of that data. Mercury periodically (typically daily)harvests metadata sources through a collection of interfaces and re-indexes these metadata to provide extremely rapid search capabilities, even over collections with tens of millions of metadata records. A number of both graphical and application interfaces have been constructed within Mercury, to enable both human users and other computer programs to perform queries. Mercury was also designed to support multiple different projects, so that the particular fields that can be queried and used with search filters are easy to configure for each different project.

  12. Mercury Toolset for Spatiotemporal Metadata

    Science.gov (United States)

    Wilson, Bruce E.; Palanisamy, Giri; Devarakonda, Ranjeet; Rhyne, B. Timothy; Lindsley, Chris; Green, James

    2010-01-01

    Mercury (http://mercury.ornl.gov) is a set of tools for federated harvesting, searching, and retrieving metadata, particularly spatiotemporal metadata. Version 3.0 of the Mercury toolset provides orders of magnitude improvements in search speed, support for additional metadata formats, integration with Google Maps for spatial queries, facetted type search, support for RSS (Really Simple Syndication) delivery of search results, and enhanced customization to meet the needs of the multiple projects that use Mercury. It provides a single portal to very quickly search for data and information contained in disparate data management systems, each of which may use different metadata formats. Mercury harvests metadata and key data from contributing project servers distributed around the world and builds a centralized index. The search interfaces then allow the users to perform a variety of fielded, spatial, and temporal searches across these metadata sources. This centralized repository of metadata with distributed data sources provides extremely fast search results to the user, while allowing data providers to advertise the availability of their data and maintain complete control and ownership of that data. Mercury periodically (typically daily) harvests metadata sources through a collection of interfaces and re-indexes these metadata to provide extremely rapid search capabilities, even over collections with tens of millions of metadata records. A number of both graphical and application interfaces have been constructed within Mercury, to enable both human users and other computer programs to perform queries. Mercury was also designed to support multiple different projects, so that the particular fields that can be queried and used with search filters are easy to configure for each different project.

  13. Adding to the Mercury Speciation Toolbox

    Science.gov (United States)

    Fitts, J. P.; Northrup, P. A.; Chidambaram, D.; Kalb, P. D.

    2007-12-01

    Mercury was used to separate lithium-6 isotope for weapons production at the Y-12 Plant in Oak Ridge, TN in the 1950s and 1960s. A large portion of the waste Hg entered the environment and continues to move throughout the sub-surface and surface waters in the area. Environmental management of Hg contamination within this complex hydrologic system, where Hg speciation and the mobile fraction have been found to vary widely, will require ongoing characterization and predictive modeling of Hg speciation. State-of-the-art spectroscopic tools that can directly probe Hg speciation in preserved aqueous and sediment samples with greater sensitivity, however, are required to determine rates and mechanisms of biogeochemical reactions. We will present the first results demonstrating the use of x-ray absorption spectroscopy (XAS) at the Hg M5 edge (2295 eV) to fingerprint Hg species. Heavy-metal M5 absorption edges can have very sharp features due to local electron transitions, and therefore, we are developing this edge as a tool for quantitative measurement of Hg species. In addition, sulfur speciation using the sulfur K absorption edge, which is at a similar energy (2472 eV), can be measured in the same scan as the Hg M5 edge. Potentially important organic and inorganic sulfur species (sulfide, disulfide, elemental sulfur, sulfite and sulfate) are readily differentiated, and thereby, provides an independent method for monitoring the redox state of the system along with changes in S-Hg bonding. We will also present x-ray microprobe 2-D concentration maps of Hg and other elements at the grain and pore scales to identify its microscopic distribution and chemical associations. When used in combination with established sequential extraction and direct spectroscopic methods, the addition of XAS at the Hg M5 edge should provide a significant advancement in the determination of Hg speciation in complex biogeochemical environments.

  14. Carbon Solubility in Silicon-Iron-Bearing Metals during Core Formation on Mercury

    Science.gov (United States)

    Vander Kaaden, Kathleen E.; McCubbin, Francis M.; Ross, D. Kent; Rapp, Jennifer F.; Danielson, Lisa R.; Keller, Lindsay P.; Righter, Kevin

    2016-01-01

    Recent results obtained from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft showed the surface of Mercury has high S abundances (approximately 4 wt%) and low Iron(II) Oxide abundances (less than 2 wt%). Based on these extreme values, the oxygen fugacity of Mercury's surface materials was estimated to be approximately 3 to 7 log(sub 10) units below the IW buffer (Delta IW-3 to Delta IW-7). This highly reducing nature of the planet has resulted in a large core and relatively thin mantle, extending to only approximately 420 km depth (corresponding to a core-mantle boundary pressure of approximately 4-7 GPa) within the planet. Furthermore, MESSENGER results have suggested the presence of carbon on the surface of the planet. Previous experimental results from have also suggested the possibility of a primary floatation crust on Mercury composed of graphite, produced after a global magma ocean event. With these exotic conditions of this compositional end-member planet, it begs the question, what is the core composition of Mercury? Although no definitive conclusion has been reached, previous studies have made advances towards answering this question. Riner et al. and Chen et al. looked at iron sulfide systems and implemented various crystallization and layered core scenarios to try and determine the composition and structure of Mercury's core. Malavergne et al. examined core crystallization scenarios in the presence of sulfur and silicon. Hauck et al. used the most recent geophysical constraints from the MESSENGER spacecraft to model the internal structure of Mercury, including the core, in a iron-sulfur-silicon system. More recently, Chabot et al. conducted a series of metal-silicate partitioning experiments in a iron-sulfur-silicon system. These results showed the core of Mercury has the potential to contain more than 15 wt% silicon. However, with the newest results from MESSENGER's low altitude campaign, carbon is another

  15. Modeling Sulfides, pH and Hydrogen Sulfide Gas in the Sewers of San Francisco

    DEFF Research Database (Denmark)

    Vollertsen, Jes; Revilla, Nohemy; Hvitved-Jacobsen, Thorkild

    2015-01-01

    An extensive measuring campaign targeted on sewer odor problems was undertaken in San Francisco. It was assessed whether a conceptual sewer process model could reproduce the measured concentrations of total sulfide in the wastewater and H2S gas in the sewer atmosphere, and to which degree...... (WATS) sewer process concept, which never had been calibrated to such an extensive dataset. The study showed that the model was capable of reproducing the general levels of wastewater sulfide, wastewater pH, and sewer H2S gas. It could also reproduce the general variability of these parameters, albeit...

  16. Hassle free synthesis of nanodimensional Ni, Cu and Zn sulfides for spectral sensing of Hg, Cd and Pb: A comparative study.

    Science.gov (United States)

    Ansari, Zarina; Singha, Shib Shankar; Saha, Abhijit; Sen, Kamalika

    2017-04-05

    A simple room temperature synthesis method of Ni, Cu and Zn sulfide nanoparticles (NPs) in aqueous medium is reported here. The NPs stabilized in aqueous medium by the citrate ions were characterized by UV-vis, ζ potentials, TEM and Raman spectroscopic techniques. The solid NPs could be isolated from the aqueous medium when allowed to stand for a prolonged time (~20h). The solids were also characterized by IR and powder X-ray analysis. The nanoparticles were further used for the development of facile optical sensing and detection of heavy metal ions at trace scale. Alterations in the absorption spectra of the generated NPs were indicative of their interactions with heavy metal ions. Raman spectral measurements further validate the detection technique. It is found that out of the three synthesized nanoparticles, nickel sulfide NP is a specific sensor for mercury ions whereas zinc sulfide and copper sulfide NPs act as sensors for Hg 2+ , Cd 2+ and Pb 2+ . Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Recent findings on sinks for sulfide in gravity sewer networks

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2006-01-01

    Sulfide buildup in sewer networks is associated with several problems, including health impacts, corrosion of sewer structures and odor nuisance. In recent years, significant advances in the knowledge of the major processes governing sulfide buildup in sewer networks have been made. This paper...... summarizes this newly obtained knowledge and emphasizes important implications of the findings. Model simulations of the in-sewer processes important for the sulfur cycle showed that sulfide oxidation in the wetted biofilm is typically the most important sink for dissolved sulfide in gravity sewers. However...

  18. Carbon steel protection in G.S. (Girlder sulfide) plants. Iron sulfide scales formation conditions. Pt. 1

    International Nuclear Information System (INIS)

    Bruzzoni, P.; Burkart, A.L.; Garavaglia, R.N.

    1981-11-01

    An ASTM A 516 degree 60 carbon steel superficial protection technique submitted to a hydrogen-water sulfide corrosive medium at 2 MPa of pressure and 40-125 deg C forming on itself an iron sulfide layer was tested. Studies on pH influence, temperature, passivating mean characteristics and exposure time as well as the mechanical resistance of sulfide layers to erosion are included. (Author) [es

  19. Phytoremediation of Ionic and Methyl Mercury Pollution

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, Richard B.

    2005-06-01

    Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems. Our current strategy is to engineer plants to

  20. Autometallographic tracing of mercury in frog liver

    International Nuclear Information System (INIS)

    Loumbourdis, N.S.; Danscher, G.

    2004-01-01

    The distribution of mercury in the liver of the frog Rana ridibunda with the autometallographic method was investigated. The mercury specific autometallographic (HgS/Se AMG ) technique is a sensitive histochemical approach for tracing mercury in tissues from mercury-exposed organisms. Mercury accumulates in vivo as mercury sulphur/mercury selenium nanocrystals that can be silver-enhanced. Thus, only a fraction of the Hg can be visualized. Six animals were exposed for one day and another group of six animals for 6 days in 1 ppm mercury (as HgCI 2 ) dissolved in fresh water. A third group of six animals, served as controls, were sacrificed the day of arrival at the laboratory. First, mercury appears in the blood plasma and erythrocytes. Next, mercury moves to hepatocytes and in the apical part of the cells, that facing bile canaliculi. In a next step, mercury appears in the endothelial and Kupffer cells. It seems likely that, the mercury of hepatocytes moves through bile canaliculi to the gut, most probably bound to glutathione and/or other similar ligands. Most probably, the endothelial and Kupffer cells comprise the first line of defense against metal toxicity. - Frogs can be good bioindicators of mercury

  1. 76 FR 64022 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

    Science.gov (United States)

    2011-10-17

    ... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for Hydrogen Sulfide. SUMMARY: EPA is announcing... (EPCRA) section 313 toxic chemical release reporting requirements for hydrogen sulfide (Chemical...

  2. Assessment of the use of sorbent amendments for reduction of mercury methylation in wetland sediments at Acadia National Park, Maine

    Science.gov (United States)

    Huntington, Thomas G.; Lewis, Ariel; Amirbahman, Aria; Marvin-DiPasquale, Mark C.; Culbertson, Charles W.

    2015-01-01

    Mercury is a contaminant of ecological concern because of its ubiquity and toxicity to fish and wildlife, and is considered a severe and ongoing threat to biota at Acadia National Park in Maine. The formation and biomagnification of methylmercury is the primary concern of resource managers at Acadia, and information is needed to develop strategies for remediation or mitigation of this contaminant. The U.S. Geological Survey in cooperation with Acadia National Park, National Park Service carried out a series of laboratory and field experiments to evaluate the potential of zero-valent iron and granular activated carbon to reduce the rate of the bacterially mediated process of mercury methylation and subsequent biological uptake by the great pond snail Lymnaea stagnalis. The addition of zero-valent iron resulted in an increase in ferrous iron that was then further oxidized to poorly crystalline amorphous ferric iron, as was anticipated. Our original hypothesis was that these reactions would reduce methylation by decreasing the concentrations of substrates for bacterial methylation (sulfide and divalent mercury) through sorption to ferric iron surfaces, formation of iron sulfide compounds, or conversion of mercury to gaseous forms and subsequent evasion. The results of our experiments did not consistently support this hypothesis. In one experiment the application of zero-valent iron increased the amount of methylmercury associated with surficial sediment. In another experiment zero-valent iron decreased the amount of methylmercury associated with surficial sediment. The addition of zero-valent iron may have stimulated mercury methylation by iron reducing bacteria and if that effect outweighed the processes that could have decreased methylation then methylation would not be decreased.

  3. Mercury: Aspects of its ecology and environmental toxicity. [physiological effects of mercury compound contamination of environment

    Science.gov (United States)

    Siegel, S. M.

    1973-01-01

    A study was conducted to determine the effects of mercury pollution on the environment. The possible sources of mercury contamination in sea water are identified. The effects of mercury on food sources, as represented by swordfish, are analyzed. The physiological effects of varying concentrations of mercury are reported. Emphasis is placed on the situation existing in the Hawaiian Islands.

  4. Groundwater Modeling Of Mercury Pollution At A Former Mercury Cell Chlor Alkali Facility In Pavoldar, Kazakhstan

    Science.gov (United States)

    In Kazakhstan, there is a serious case of mercury pollution near the city of Pavlodar from an old mercury cell chlor-alkali plant. The soil, sediment, and water is severly contaminated with mercury and mercury compounds as a result of the industrial activity of this chemical pla...

  5. Sulfidation behavior of rhenium and cobalt-rhenium alloys

    International Nuclear Information System (INIS)

    Shiring, R.; Douglass, D.L.

    1999-01-01

    The sulfidation behavior of Re and three Co-Re alloys, 15, 30, and 45 w/o, was studied over the temperature range 700--800 C at sulfur pressures of 10 -4 and 10 -2 atm. The kinetics of sulfidation followed the parabolic rate law and the activation energies for all alloys were similar to that of pure cobalt. A positive rate dependency on sulfur pressure was observed and Pt markers were located at the metal-scale interface, both observations clearly suggesting that outward cation diffusion through a P-type sulfide scale occurred. Two dominant sulfides, Co 9 S 8 and ReS 2 , formed. Weight gains decreased for a given set of conditions with increasing rhenium content. An order of magnitude decrease in the sulfidation rate occurred as the rhenium content increased from 15 to 45 w/o. Preferential sulfidation of cobalt initially occurred, causing a rhenium-enriched zone to form in the substrate beneath the cobalt-sulfide scale. The initial sulfide to form was Co 3 S 4 , but, subsequently, Co 9 S 8 became the dominant sulfide, forming beneath the outer Co 3 S 4 layer. ReS 2 formed at lower cobalt levels. Pure Re was also studied, the sulfidation rate being about 10 4 times slower than that of cobalt. The decreasing rate of sulfidation with increasing Re content is attributed primarily to slower cobalt diffusion outward through the Re-enriched substrate, a phenomenon similar to that observed by C. Wagner for the oxidation of Ni-Pt alloys

  6. Sorption of mercury on chemically synthesized polyaniline

    International Nuclear Information System (INIS)

    Remya Devi, P.S.; Verma, R.; Sudersanan, M.

    2006-01-01

    Sorption of inorganic mercury (Hg 2+ ) and methyl mercury, on chemically synthesized polyaniline, in 0.1-10N HCl solutions has been studied. Hg 2+ is strongly sorbed at low acidities and the extent of sorption decreases with increase in acidity. The sorption of methyl mercury is very low in the HCl concentration range studied. Sorption of Hg 2+ on polyaniline in 0.1-10N LiCl and H 2 SO 4 solutions has also been studied. The analysis of the data indicates that the sorption of Hg 2+ depends on the degree of protonation of polyaniline and the nature of mercury(II) chloride complexes in solution. X-ray photoelectron spectroscopy analysis (XPS) of polyaniline sorbed with mercury show that mercury is bound as Hg 2+ . Sorbed mercury is quantitatively eluted from polyaniline with 0.5N HNO 3 . Polyaniline can be used for separation and pre-concentration of inorganic mercury from aqueous samples. (author)

  7. EPA Leadership in the Global Mercury Partnership

    Science.gov (United States)

    The Global Mercury Partnership is a voluntary multi-stakeholder partnership initiated in 2005 to take immediate actions to protect human health and the environment from the releases of mercury and its compounds to the environment.

  8. Mercury-Containing Devices and Demolition

    Science.gov (United States)

    Some items inside residential buildings contain mercury, which poses a persistent and toxic human health and environmental threat. These materials should be carefully salvaged for proper recycling to prevent mercury contamination prior to demolition.

  9. Health Effects of Exposures to Mercury

    Science.gov (United States)

    ... Mercury in Your Environment Contact Us Share Health Effects of Exposures to Mercury Related Health Information for ... About PDF ; discussion starts on page 20) Methylmercury Effects Effects on People of All Ages Exposure to ...

  10. The effect of longterm exposure to mercury on the bacterial community in marine sediment

    DEFF Research Database (Denmark)

    Rasmussen, Lasse Dam; Sørensen, Søren Johannes

    1998-01-01

    Mercury pollution, bacteria, diversity, mercury resistance, antibiotic resistance, plasmid abundance......Mercury pollution, bacteria, diversity, mercury resistance, antibiotic resistance, plasmid abundance...

  11. Method for the removal and recovery of mercury

    Science.gov (United States)

    Easterly, Clay E.; Vass, Arpad A.; Tyndall, Richard L.

    1997-01-01

    The present invention is an enhanced method for the removal and recovery of mercury from mercury-contaminated matrices. The method involves contacting a mercury-contaminated matrix with an aqueous dispersant solution derived from specific intra-amoebic isolates to release the mercury from the mercury-contaminated matrix and emulsify the mercury; then, contacting the matrix with an amalgamating metal from a metal source to amalgamate the mercury to the amalgamating metal; removing the metallic source from the mercury-contaminated matrix; and heating the metallic source to vaporize the mercury in a closed system to capture the mercury vapors.

  12. Phytoremediation of Ionic and Methyl Mercury Pollution

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, Richard B.

    2004-12-01

    Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems.

  13. Mercury Continuous Emmission Monitor Calibration

    Energy Technology Data Exchange (ETDEWEB)

    John Schabron; Eric Kalberer; Ryan Boysen; William Schuster; Joseph Rovani

    2009-03-12

    Mercury continuous emissions monitoring systems (CEMs) are being implemented in over 800 coal-fired power plant stacks throughput the U.S. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor calibrators/generators. These devices are used to calibrate mercury CEMs at power plant sites. The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005 and vacated by a Federal appeals court in early 2008 required that calibration be performed with NIST-traceable standards. Despite the vacature, mercury emissions regulations in the future will require NIST traceable calibration standards, and EPA does not want to interrupt the effort towards developing NIST traceability protocols. The traceability procedures will be defined by EPA. An initial draft traceability protocol was issued by EPA in May 2007 for comment. In August 2007, EPA issued a conceptual interim traceability protocol for elemental mercury calibrators. The protocol is based on the actual analysis of the output of each calibration unit at several concentration levels ranging initially from about 2-40 {micro}g/m{sup 3} elemental mercury, and in the future down to 0.2 {micro}g/m{sup 3}, and this analysis will be directly traceable to analyses by NIST. The EPA traceability protocol document is divided into two separate sections. The first deals with the qualification of calibrator models by the vendors for use in mercury CEM calibration. The second describes the procedure that the vendors must use to certify the calibrators that meet the qualification specifications. The NIST traceable certification is performance based, traceable to analysis using isotope dilution inductively coupled plasma

  14. Mercury detection with thermal neutrons

    International Nuclear Information System (INIS)

    Bell, Z.W.

    1994-01-01

    This report describes the work performed to design a gauge to detect mercury concealed within walls, floors, pipes, and equipment inside a building. The project arose out of a desire to decontaminate and decommission (D ampersand D) a building in which mercury had been used as part of a chemical process. The building contains plumbing and equipment, some with residual mercury even after draining, sumps, and hollow walls. So that releases of mercury to the environment might be minimized during D ampersand D activities, it was considered advisable to locate pockets of mercury that may have collected in concealed spaces so that they might be drained in a controlled fashion prior to the application of the wrecking ball or sledge hammer. The detection of such pockets within a building presents some problems not ordinarily encountered in a laboratory environment. Often, only a single side of a wall or pipe is accessible. This condition disqualifies transmission gauges (such as conventional x radiography) in which a probe is sent through the volume under test (VUT) from one side and its passage or attenuation is detected on the opposite side. A robust, one-sided system was needed

  15. Mercury bioaccumulation in the Mediterranean

    Directory of Open Access Journals (Sweden)

    Cinnirella S.

    2013-04-01

    Full Text Available This study details mercury pollution within the food chain of the Mediterranean by analysing the most comprehensive mercury dataset available for biota and water measurements. In this study we computed a bioaccumulation factor (BAF for datasets in the existing mercury-related scientific literature, in on-going programs, and in past measurement campaigns. Preliminary results indicate a major lack of information, making the outcome of any assessment very uncertain. Importantly, not all marine eco-regions are (or have ever been covered by measurement campaigns. Most lacking is information associated with the South-Eastern part of the Mediterranean, and in several eco-regions it is still impossible to reconstruct a trophic net, as the required species were not accounted for when mercury measurements were taken. The datasets also have additional temporal sampling problems, as species were often not sampled systematically (but only sporadically during any given sampling period. Moreover, datasets composed of mercury concentrations in water also suffer from similar geographic limitations, as they are concentrated in the North-Western Mediterranean. Despite these concerns, we found a very clear bioaccumulation trend in 1999, the only year where comprehensive information on both methylmercury concentrations in water and biota was available.

  16. Technetium behavior in sulfide and ferrous iron solutions

    International Nuclear Information System (INIS)

    Lee, S.Y.; Bondietti, E.A.

    1982-01-01

    Pertechnetate oxyanion ( 99 TcO 4- ), a potentially mobile species in leachate from a breached radioactive waste repository, was removed from a brine solution by precipitation with sulfide, iron, and ferrous sulfide at environmental pH's. Maghemite (ν-Fe 2 O 3 ) and geothite (α-FeOOH) were the dominant minerals in the precipitate obtained from the TcO 4- -ferrous iron reaction. The observation of small particle size and poor crystallinity of the minerals formed in the presence of Tc suggested that the Tc was incorporated into the mineral structure after reduction to a lower valence state. Amorphous ferrous sulfide, an initial phase precipitating in the TcO 4- -ferrous iron-sulfide reaction, was transformed to goethite and hematite (α-Fe 2 O 3 ) on aging. The black precipitate obtained from the TcO 4- -sulfide reaction was poorly crystallized technetium sulfide (Tc 2 S 7 ) which was insoluble in both acid and alkaline solution in the absence of strong oxidents. The results suggested that ferrous- and/or sulfide-bearing groundwaters and minerals in host rocks or backfill barriers could reduce the mobility of Tc through the formation of less-soluble Tc-bearing iron and/or sulfide minerals

  17. Petroleum sulfides, sulfoxides, and sulfones used as extragents

    International Nuclear Information System (INIS)

    Nikitin, Yu.E.; Lyapina, N.K.; Murinov, Yu.I.

    1988-01-01

    Possibilities of using petroleum sulfides, sulfoxides and sulfones for extraction and separation of wide range of elements are considered. It is shown that petroleum sulfides appear to be effective and selective extractants in extraction and separation of noble metals (Ru, Au, Pt, etc.). Petroleum sulfoxides are promising for solvent extraction of transition metals, actinides, rare earths etc

  18. Effect of Soluble Sulfide on the Activity of Luminescent Bacteria

    Directory of Open Access Journals (Sweden)

    Feng Wang

    2012-05-01

    Full Text Available Sulfide is an important water pollutant widely found in industrial waste water that has attracted much attention. S2−, as a weak acidic anion, is easy hydrolyzed to HS and H2S in aqueous solution. In this study, biological tests were performed to establish the toxicity of sulfide solutions on luminescent bacteria. Considering the sulfide solution was contained three substances—S2−, HS and H2S—the toxicity test was performed at different pH values to investigate which form of sulfide increased light emission and which reduced light emission. It was shown that the EC50 values were close at pH 7.4, 8.0 and 9.0 which were higher than pH 5 and 10. The light emission and sulfide concentrations displayed an inverse exponential dose-response relationship within a certain concentration range at pH 5, 6.5 and 10. The same phenomenon occurred for the high concentration of sulfide at pH 7.4, 8 and 9, in which the concentration of sulfide was HS >> H2S > S2−. An opposite hormesis-effect appeared at the low concentrations of sulfide.

  19. Mineral resource of the month: mercury

    Science.gov (United States)

    ,

    2012-01-01

    The article offers information on mercury, a mineral commodity used in industrial and small-scale gold mining applications. Mercury has been reported to be used for amalgamation with gold since the Roman times. Mercury from cinnabar from Almadén, Spain has been used by Romans and has been continued to be used through the Middle Ages and the Colonial era.

  20. 40 CFR 721.10068 - Elemental mercury.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Elemental mercury. 721.10068 Section... Substances § 721.10068 Elemental mercury. (a) Definitions. The definitions in § 721.3 apply to this section... elemental mercury (CAS. No. 7439-97-6) is subject to reporting under this section for the significant new...

  1. Hydrogen sulfide: from brain to gut.

    Science.gov (United States)

    Kimura, Hideo

    2010-05-01

    Three hundred years have passed since the first description of the toxicity of hydrogen sulfide (H(2)S). Three papers in 1989 and 1990 described relatively high concentrations of sulfide in the brain. In 1996 we demonstrated that cystathionine beta-synthase (CBS) is a H(2)S producing enzyme in the brain and that H(2)S enhances the activity of NMDA receptors and facilitates the induction of hippocampal long-term potentiation (LTP), a synaptic model of memory. In the following year, we demonstrated that another H(2)S producing enzyme, cystathionine gamma-lyase is in the thoracic aorta, portal vein, and the ileum, and that H(2)S relaxes these tissues. Based on these observations we proposed H(2)S as a neuromodulator as well as a smooth muscle relaxant. We recently demonstrated that the third H(2)S-producing enzyme, 3-mercaptopyruvate sulfurtransferase (3MST) along with cysteine aminotransferase (CAT) produces H(2)S in the brain as well as in vascular endothelium. Various functions in many tissues have been proposed. H(2)S protects neurons and cardiac muscle from oxidative stress. H(2)S has pro- and anti-inflammatory effects, nociceptive effects, the regulatory function of insulin release, and is even involved in longevity. Recent progress in the studies of physiological functions of H(2)S in neurons and smooth muscle was described.

  2. Sulindac Sulfide, but Not Sulindac Sulfone, Inhibits Colorectal Cancer Growth

    Directory of Open Access Journals (Sweden)

    Christopher S. Williams

    1999-06-01

    Full Text Available Sulindac sulfide, a metabolite of the nonsteroidal antiinflammatory drug (NSAID sulindac sulfoxide, is effective at reducing tumor burden in both familial adenomatous polyposis patients and in animals with colorectal cancer. Another sulindac sulfoxide metabolite, sulindac sulfone, has been reported to have antitumor properties without inhibiting cyclooxygenase activity. Here we report the effect of sulindac sulfone treatment on the growth of colorectal carcinoma cells. We observed that sulindac sulfide or sulfone treatment of HCA-7 cells led to inhibition of prostaglandin E2 production. Both sulindac sulfide and sulfone inhibited HCA-7 and HCT-116 cell growth in vitro. Sulindac sulfone had no effect on the growth of either HCA-7 or HCT-116 xenografts, whereas the sulfide derivative inhibited HCA-7 growth in vivo. Both sulindac sulfide and sulfone inhibited colon carcinoma cell growth and prostaglandin production in vitro, but sulindac sulfone had no effect on the growth of colon cancer cell xenografts in nude mice.

  3. The Hydrolysis of Carbonyl Sulfide at Low Temperature: A Review

    Science.gov (United States)

    Zhao, Shunzheng; Yi, Honghong; Tang, Xiaolong; Jiang, Shanxue; Gao, Fengyu; Zhang, Bowen; Zuo, Yanran; Wang, Zhixiang

    2013-01-01

    Catalytic hydrolysis technology of carbonyl sulfide (COS) at low temperature was reviewed, including the development of catalysts, reaction kinetics, and reaction mechanism of COS hydrolysis. It was indicated that the catalysts are mainly involved metal oxide and activated carbon. The active ingredients which can load on COS hydrolysis catalyst include alkali metal, alkaline earth metal, transition metal oxides, rare earth metal oxides, mixed metal oxides, and nanometal oxides. The catalytic hydrolysis of COS is a first-order reaction with respect to carbonyl sulfide, while the reaction order of water changes as the reaction conditions change. The controlling steps are also different because the reaction conditions such as concentration of carbonyl sulfide, reaction temperature, water-air ratio, and reaction atmosphere are different. The hydrolysis of carbonyl sulfide is base-catalyzed reaction, and the force of the base site has an important effect on the hydrolysis of carbonyl sulfide. PMID:23956697

  4. Hierarchical Architecturing for Layered Thermoelectric Sulfides and Chalcogenides

    Science.gov (United States)

    Jood, Priyanka; Ohta, Michihiro

    2015-01-01

    Sulfides are promising candidates for environment-friendly and cost-effective thermoelectric materials. In this article, we review the recent progress in all-length-scale hierarchical architecturing for sulfides and chalcogenides, highlighting the key strategies used to enhance their thermoelectric performance. We primarily focus on TiS2-based layered sulfides, misfit layered sulfides, homologous chalcogenides, accordion-like layered Sn chalcogenides, and thermoelectric minerals. CS2 sulfurization is an appropriate method for preparing sulfide thermoelectric materials. At the atomic scale, the intercalation of guest atoms/layers into host crystal layers, crystal-structural evolution enabled by the homologous series, and low-energy atomic vibration effectively scatter phonons, resulting in a reduced lattice thermal conductivity. At the nanoscale, stacking faults further reduce the lattice thermal conductivity. At the microscale, the highly oriented microtexture allows high carrier mobility in the in-plane direction, leading to a high thermoelectric power factor. PMID:28787992

  5. Influence of Water Salinity on Air Purification from Hydrogen Sulfide

    Directory of Open Access Journals (Sweden)

    Leybovych L.I.

    2015-12-01

    Full Text Available Mathematical modeling of «sliding» water drop motion in the air flow was performed in software package FlowVision. The result of mathematical modeling of water motion in a droplet with diameter 100 microns at the «sliding» velocity of 15 m/s is shown. It is established that hydrogen sulfide oxidation occurs at the surface of phases contact. The schematic diagram of the experimental setup for studying air purification from hydrogen sulfide is shown. The results of the experimental research of hydrogen sulfide oxidation by tap and distilled water are presented. The dependence determining the share of hydrogen sulfide oxidized at the surface of phases contact from the dimensionless initial concentration of hydrogen sulfide in the air has been obtained.

  6. Technology Evaluations Related to Mercury, Technetium, and Chloride in Treatment of Wastes at the Idaho Nuclear Technology and Engineering Center of the Idaho National Engineering and Environmental Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    C. M. Barnes; D. D. Taylor; S. C. Ashworth; J. B. Bosley; D. R. Haefner

    1999-10-01

    The Idaho High-Level Waste and Facility Disposition Environmental Impact Statement defines alternative for treating and disposing of wastes stored at the Idaho Nuclear Technology and Engineering Center. Development is required for several technologies under consideration for treatment of these wastes. This report contains evaluations of whether specific treatment is needed and if so, by what methods, to remove mercury, technetium, and chlorides in proposed Environmental Impact Statement treatment processes. The evaluations of mercury include a review of regulatory requirements that would apply to mercury wastes in separations processes, an evaluation of the sensitivity of mercury flowrates and concentrations to changes in separations processing schemes and conditions, test results from laboratory-scale experiments of precipitation of mercury by sulfide precipitation agents from the TRUEX carbonate wash effluent, and evaluations of methods to remove mercury from New Waste Calcining Facility liquid and gaseous streams. The evaluation of technetium relates to the need for technetium removal and alternative methods to remove technetium from streams in separations processes. The need for removal of chlorides from New Waste Calcining Facility scrub solution is also evaluated.

  7. Technology Evaluations Related to Mercury, Technetium, and Chloride in Treatment of Wastes at the Idaho Nuclear Technology and Engineering Center of the Idaho National Engineering and Environmental Laboratory

    International Nuclear Information System (INIS)

    Barnes, C.M.; Taylor, D.D.; Ashworth, S.C.; Bosley, J.B.; Haefner, D.R.

    1999-01-01

    The Idaho High-Level Waste and Facility Disposition Environmental Impact Statement defines alternative for treating and disposing of wastes stored at the Idaho Nuclear Technology and Engineering Center. Development is required for several technologies under consideration for treatment of these wastes. This report contains evaluations of whether specific treatment is needed and if so, by what methods, to remove mercury, technetium, and chlorides in proposed Environmental Impact Statement treatment processes. The evaluations of mercury include a review of regulatory requirements that would apply to mercury wastes in separations processes, an evaluation of the sensitivity of mercury flowrates and concentrations to changes in separations processing schemes and conditions, test results from laboratory-scale experiments of precipitation of mercury by sulfide precipitation agents from the TRUEX carbonate wash effluent, and evaluations of methods to remove mercury from New Waste Calcining Facility liquid and gaseous streams. The evaluation of technetium relates to the need for technetium removal and alternative methods to remove technetium from streams in separations processes. The need for removal of chlorides from New Waste Calcining Facility scrub solution is also evaluated

  8. How Tiny Collisions Shape Mercury

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    If space rocks are unpleasant to encounter, space dust isnt much better. Mercurys cratered surface tells of billions of years of meteoroid impacts but its thin atmosphere is what reveals its collisional history with smaller impactors. Now new research is providing a better understanding of what were seeing.Micrometeoroids Ho!The inner solar system is bombarded by micrometeoroids, tiny particles of dust (on the scale of a tenth of a millimeter) emitted by asteroids and comets as they make their closest approach to the Sun. This dust doesnt penetrateEarths layers of atmosphere, but the innermost planet of our solar system, Mercury, doesnt have this convenient cushioning.Just as Mercury is affected by the impacts of large meteoroids, its also shaped by the many smaller-scale impacts it experiences. These tiny collisions are thought to vaporize atoms and molecules from the planets surface, which quickly dissociate. This process adds metals to Mercurys exosphere, the planets extremely tenuous atmosphere.Modeling PopulationsDistribution of the directions from which meteoroids originate before impacting Mercurys surface, as averaged over its entire orbit. Local time of 12 hr corresponds to the Sun-facing side. A significant asymmetry is seen between the dawn (6 hrs) and dusk (18 hrs) rates. [Pokorn et al. 2017]The metal distribution in the exosphere provides a way for us to measure the effect of micrometeoroid impacts on Mercury but this only works if we have accurate models of the process. A team of scientists led by Petr Pokorn (The Catholic University of America and NASA Goddard SFC) has now worked to improve our picture of micrometeoroid impact vaporization on Mercury.Pokorn and collaborators argue that two meteoroid populations Jupiter-family comets (short-period) and Halley-type comets (long-period) contribute the dust for the majority of micrometeoroid impacts on Mercury. The authors model the dynamics and evolution of these two populations, reproducing the

  9. Control of mercury emissions: policies, technologies, and future trends

    OpenAIRE

    Rhee, Seung-Whee

    2015-01-01

    Seung-Whee Rhee Department of Environmental Engineering, Kyonggi University, Suwon, Republic of Korea Abstract: Owing to the Minamata Convention on Mercury and the Global Mercury Partnership, policies and regulations on mercury management in advanced countries were intensified by a mercury phaseout program in the mercury control strategy. In developing countries, the legislative or regulatory frameworks on mercury emissions are not established specifically, but mercury management is designed...

  10. Biogeochemical transformations of mercury in solid waste landfills and pathways for release.

    Science.gov (United States)

    Lee, Sung-Woo; Lowry, Gregory V; Hsu-Kim, Heileen

    2016-02-01

    Mercury (Hg) is present in a variety of solid wastes including industrial wastes, household products, consumer electronics, and medical wastes, some of which can be disposed in conventional landfills. The presence of this neurotoxic metal in landfills is a concern due to the potential for it to leach or volatilize from the landfill and impact local ecosystems. The objective of this review is to describe general practices for the disposal of mercury-bearing solid wastes, summarize previous studies on the release of mercury from landfills, and delineate the expected transformations of Hg within landfill environments that would influence transport of Hg via landfill gas and leachate. A few studies have documented the emissions of Hg as landfill gas, primarily as gaseous elemental Hg(0) and smaller amounts as methylated Hg species. Much less is known regarding the release of Hg in leachate. Landfill conditions are unique from other subsurface environments in that they can contain water with very high conductivity and organic carbon concentration. Landfills also experience large changes in redox potential (and the associated microbial community) that greatly influence Hg speciation, transformations, and mobilization potential. Generally, Hg is not likely to persist in large quantities as dissolved species, since Hg(0) tends to evolve in the gas phase and divalent Hg(ii) sorbs strongly to particulate phases including organic carbon and sulfides. However, Hg(ii) has the potential to associate with or form colloidal particles that can be mobilized in porous media under high organic carbon conditions. Moreover, the anaerobic conditions within landfills can foster the growth of microorganisms that produced monomethyl- and dimethyl-Hg species, the forms of mercury with high potential for bioaccumulation. Much advancement has recently been made in the mercury biogeochemistry research field, and this study seeks to incorporate these findings for landfill settings.

  11. Canadian mercury inventories: the missing pieces

    Energy Technology Data Exchange (ETDEWEB)

    Hagreen, L.A.; Lourie, B.A. [Summerhill Group, Toronto, ON (Canada)

    2004-07-01

    Research was conducted to determine the significance of the deliberate use of mercury in products in Canada and the associated releases from these sources. Through a combination of literature review and new calculations, the reservoir, flux, and releases of mercury from eight product sources were calculated, and these results compared to historical Canadian inventories. Mercury contributions from the waste sector were also assessed and compared to total Canadian mercury releases and to mercury releases from coal-fired generating stations. Results suggest the use and release of mercury associated with its use in products is 4.5 times what previous inventories indicate. Including dental amalgam and sewage sludge, the total releases of mercury to all environmental compartments in Canada totals 20 tonnes per year. This accounts for less than one-half of the 44 tonnes per year of mercury released from mercury waste disposal each year in Canada. Waste mercury contributions from hazardous waste imports, unknown product sources, and incomplete information on the use of mercury in known products may account for this discrepancy. Waste-related mercury releases and transfers for disposal and recycling are 11 times greater than that of electricity generation in Canada. Results indicate that Canadian inventories have underestimated the significance of mercury use and release associated with products, calling into question the current priorities for mercury management. This paper was developed as part of a panel session at the International Joint Commission 'Mercury in the Ecosystem' workshop, February 26-27, 2003, Windsor, ON, Canada, as a complement to the information on Canadian Inventories presented by Luke Trip (Senes Consulting, Ottawa, ON, Canada).

  12. Sodium Velocity Maps on Mercury

    Science.gov (United States)

    Potter, A. E.; Killen, R. M.

    2011-01-01

    The objective of the current work was to measure two-dimensional maps of sodium velocities on the Mercury surface and examine the maps for evidence of sources or sinks of sodium on the surface. The McMath-Pierce Solar Telescope and the Stellar Spectrograph were used to measure Mercury spectra that were sampled at 7 milliAngstrom intervals. Observations were made each day during the period October 5-9, 2010. The dawn terminator was in view during that time. The velocity shift of the centroid of the Mercury emission line was measured relative to the solar sodium Fraunhofer line corrected for radial velocity of the Earth. The difference between the observed and calculated velocity shift was taken to be the velocity vector of the sodium relative to Earth. For each position of the spectrograph slit, a line of velocities across the planet was measured. Then, the spectrograph slit was stepped over the surface of Mercury at 1 arc second intervals. The position of Mercury was stabilized by an adaptive optics system. The collection of lines were assembled into an images of surface reflection, sodium emission intensities, and Earthward velocities over the surface of Mercury. The velocity map shows patches of higher velocity in the southern hemisphere, suggesting the existence of sodium sources there. The peak earthward velocity occurs in the equatorial region, and extends to the terminator. Since this was a dawn terminator, this might be an indication of dawn evaporation of sodium. Leblanc et al. (2008) have published a velocity map that is similar.

  13. Coal fired flue gas mercury emission controls

    CERN Document Server

    Wu, Jiang; Pan, Weiguo; Pan, Weiping

    2015-01-01

    Mercury (Hg) is one of the most toxic heavy metals, harmful to both the environment and human health. Hg is released into the atmosphere from natural and anthropogenic sources and its emission control has caused much concern. This book introduces readers to Hg pollution from natural and anthropogenic sources and systematically describes coal-fired flue gas mercury emission control in industry, especially from coal-fired power stations. Mercury emission control theory and experimental research are demonstrated, including how elemental mercury is oxidized into oxidized mercury and the effect of

  14. Carbon steel protection in G.S. (Girlder sulfide) plants. Pressure influence on iron sulfide scales formation. Pt. 5

    International Nuclear Information System (INIS)

    Delfino, C.A.; Lires, O.A.; Rojo, E.A.

    1987-01-01

    In order to protect carbon steel towers and piping of Girlder sulfide (G.S.) experimental heavy water plants against corrosion produced by the action of aqueous solutions of hydrogen sulfide, a method, previously published, was developed. Carbon steel, exposed to saturated aqueous solutions of hydrogen sulfide, forms iron sulfide scales. In oxygen free solutions evolution of corrosion follows the sequence: mackinawite → cubic ferrous sulfide → troilite → pyrrotite → pyrite. Scales formed by pyrrotite-pyrite or pyrite are the most protective layers (these are obtained at 130 deg C, 2MPa, for periods of 14 days). Experiments, at 125 deg C and periods of 10-25 days, were performed in two different ways: 1- constant pressure operations at 0.5 and 1.1 MPa. 2- variable pressure operation between 0.3-1 MPa. In all cases pyrrotite-pyrite scales were obtained. (Author) [es

  15. Marine biogeochemistry of mercury

    International Nuclear Information System (INIS)

    Gill, G.A.

    1986-01-01

    Noncontaminating sample collection and handling procedures and accurate and sensitive analysis methods were developed to measure sub-picomolar Hg concentrations in seawater. Reliable and diagnostic oceanographic Hg distributions were obtained, permitting major processes governing the marine biogeochemistry of Hg to be identified. Mercury concentrations in the northwest Atlantic, central Pacific, southeast Pacific, and Tasman Sea ranged from 0.5 to 12 pM. Vertical Hg distributions often exhibited a maximum within or near the main thermocline. At similar depths, Hg concentrations in the northwest Atlantic Ocean were elevated compared to the N. Pacific Ocean. This pattern appears to result from a combination of enhanced supply of Hg to the northwest Atlantic by rainfall and scavenging removal along deep water circulation pathways. These observations are supported by geochemical steady-state box modelling which predicts a relatively short mean residence time for Hg in the oceans; demonstrating the reactive nature of Hg in seawater and precluding significant involvement in nutrient-type recyclic. Evidence for the rapid removal of Hg from seawater was obtained at two locations. Surface seawater Hg measurements along 160 0 W (20 0 N to 20 0 S) showed a depression in the equatorial upwelling area which correlated well with the transect region exhibiting low 234 Th/ 238 U activity ratios. This relationship implies that Hg will be scavenged and removed from surface seawater in biologically productive oceanic zones. Further, a broad minimum in the vertical distribution of Hg was observed to coincide with the intense oxygen minimum zone in the water column in coastal waters off Peru

  16. Effect of Cys, GSH, and pH on Mercury Release from Tibetan Medicine Zuotai, β-HgS, and α-HgS in Artificial Gastrointestinal Juices.

    Science.gov (United States)

    Zheng, Zhiyuan; Zhang, Ming; Xiao, Yuancan; Wei, Lixin; Li, Cen

    2017-11-12

    Zuotai, also named as "gTso thal", a known Tibetan medicinal mixture containing insoluble cubic crystal mercuric sulfide (β-HgS), has been used to treat diseases with long history. The mercury release ratio from Zuotai in gastrointestinal environment is one determinant factor for its bioavailability and biological effect. However, the information is still scarce now. Therefore, the study was designed to investigate the effect of sulfhydryl biomolecules [L-cysteine (Cys) and glutathione (GSH)] and pH on mercury dissociation from Zuotai, β-HgS, and hexagonal crystal mercuric sulfide (α-HgS) in artificial gastrointestinal juices or pure water with a 1:100 solid-liquid ratio. And, the digestion and peristalsis of gastrointestinal tract were simulated in vitro. The results showed the following trend for the mercury release ratio of Zuotai, artificial gastric juice > artificial intestinal juice > pure water, whereas the trend for β-HgS and α-HgS was as follows, artificial intestinal fluid > artificial gastric fluid > pure water. The mercury release ratios of Zuotai, β-HgS, and α-HgS significantly increased in artificial intestinal juice containing L-Cys or GSH compared to those without sulfhydryl biomolecules in the juice. However, in contrast to the results observed for β-HgS and α-HgS, the mercury release ratio of Zuotai was reduced remarkably in pure water and artificial gastric juice with Cys or GSH. And, we found that strong acidic or strong alkaline environments promoted the dissociation of mercury from Zuotai, β-HgS, and α-HgS. Taken together, current findings may contribute to other studies regarding clinical safety and bioavailability of the traditional drug Zuotai containing β-HgS.

  17. Environmental contamination and risk assessment of mercury from a historic mercury mine located in southwestern China.

    Science.gov (United States)

    Li, Yonghua

    2013-02-01

    A field survey of mercury pollution in environmental media and human hair samples obtained from residents living in the area surrounding the Chatian mercury mine (CMM) of southwestern China was conducted to evaluate the health risks of mercury to local residents. The results showed that mine waste, and tailings in particular, contained high levels of mercury and that the maximum mercury concentration was 88.50 μg g(-1). Elevated mercury levels were also found in local surface water, paddy soil, and paddy grain, which may cause severe health problems. The mercury concentration of hair samples from the inhabitants of the CMM exceeded 1.0 μg g(-1), which is the limit recommended by the US EPA. Mercury concentrations in paddy soil were positively correlated with mercury concentrations in paddy roots, stalks, and paddy grains, which suggested that paddy soil was the major source of mercury in paddy plant tissue. The average daily dose (ADD) of mercury for local adults and preschool children via oral exposure reached 0.241 and 0.624 μg kg(-1) body weight per day, respectively, which is approaching or exceeds the provisional tolerable daily intake. Among the three oral exposure routes, the greatest contributor to the ADD of mercury was the ingestion of rice grain. Open-stacked mine tailings have resulted in heavy mercury contamination in the surrounding soil, and the depth of appreciable soil mercury concentrations exceeded 100 cm.

  18. Mercury accumulation plant Cyrtomium macrophyllum and its potential for phytoremediation of mercury polluted sites.

    Science.gov (United States)

    Xun, Yu; Feng, Liu; Li, Youdan; Dong, Haochen

    2017-12-01

    Cyrtomium macrophyllum naturally grown in 225.73 mg kg -1 of soil mercury in mining area was found to be a potential mercury accumulator plant with the translocation factor of 2.62 and the high mercury concentration of 36.44 mg kg -1 accumulated in its aerial parts. Pot experiments indicated that Cyrtomium macrophyllum could even grow in 500 mg kg -1 of soil mercury with observed inhibition on growth but no obvious toxic effects, and showed excellent mercury accumulation and translocation abilities with both translocation and bioconcentration factors greater than 1 when exposed to 200 mg kg -1 and lower soil mercury, indicating that it could be considered as a great mercury accumulating species. Furthermore, the leaf tissue of Cyrtomium macrophyllum showed high resistance to mercury stress because of both the increased superoxide dismutase activity and the accumulation of glutathione and proline induced by mercury stress, which favorited mercury translocation from the roots to the aerial parts, revealing the possible reason for Cyrtomium macrophyllum to tolerate high concentration of soil mercury. In sum, due to its excellent mercury accumulation and translocation abilities as well as its high resistance to mercury stress, the use of Cyrtomium macrophyllum should be a promising approach to remediating mercury polluted soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Inorganic mercury binding with different sulfur species in anoxic sediments and their gut juice extractions.

    Science.gov (United States)

    Zhong, Huan; Wang, Wen-Xiong

    2009-09-01

    To investigate the roles of different sulfur (S) species in controlling the partitioning and bioavailability of inorganic mercury (Hg) in anoxic sediments, we examined the differential binding of Hg with three key S species in anoxic sediment (mackinawite [FeS], pyrite [FeS2], and S(2-)) and then quantified their extraction by the gut juice of deposit-feeding sipunculans Sipunculus nudus. A sequential extraction method was simultaneously used to distinguish Hg sorption with different sediment components. All three S-containing sediment components could lead to a high binding of Hg in sediments, but most Hg was sorbed with FeS or FeS2 instead of formation of Hg sulfide despite the presence of S(2-) or humic acid. The gut juice extraction was relatively low and constant whenever FeS and FeS2 were in the sediment, indicating that both FeS and FeS2 controlled the Hg gut juice extraction and thus bioavailability. Mercury sorbed with FeS2 had higher gut juice extraction than that with FeS, while Hg sulfide was not extracted, strongly suggesting that Hg sorbed with FeS2 was more bioavailable than that with other S species. Mercury sorbed with FeS had very low bioavailability to sipunculans at a low Hg:S ratio in the sediment but was more bioavailable with increasing Hg:S ratio up to a maximum (approximately 1:10, mole based). The present study showed that different S species (FeS, FeS2) and Hg:S ratios significantly affected the binding and bioavailability of Hg in anoxic sediments.

  20. Amorphous molybdenum sulfides as hydrogen evolution catalysts.

    Science.gov (United States)

    Morales-Guio, Carlos G; Hu, Xile

    2014-08-19

    Providing energy for a population projected to reach 9 billion people within the middle of this century is one of the most pressing societal issues. Burning fossil fuels at a rate and scale that satisfy our near-term demand will irreversibly damage the living environment. Among the various sources of alternative and CO2-emission-free energies, the sun is the only source that is capable of providing enough energy for the whole world. Sunlight energy, however, is intermittent and requires an efficient storage mechanism. Sunlight-driven water splitting to make hydrogen is widely considered as one of the most attractive methods for solar energy storage. Water splitting needs a hydrogen evolution catalyst to accelerate the rate of hydrogen production and to lower the energy loss in this process. Precious metals such as Pt are superior catalysts, but they are too expensive and scarce for large-scale applications. In this Account, we summarize our recent research on the preparation, characterization, and application of amorphous molybdenum sulfide catalysts for the hydrogen evolution reaction. The catalysts can be synthesized by electrochemical deposition under ambient conditions from readily available and inexpensive precursors. The catalytic activity is among the highest for nonprecious catalysts. For example, at a loading of 0.2 mg/cm(2), the optimal catalyst delivers a current density of 10 mA/cm(2) at an overpotential of 160 mV. The growth mechanism of the electrochemically deposited film catalysts was revealed by an electrochemical quartz microcrystal balance study. While different electrochemical deposition methods produce films with different initial compositions, the active catalysts are the same and are identified as a "MoS(2+x)" species. The activity of the film catalysts can be further promoted by divalent Fe, Co, and Ni ions, and the origins of the promotional effects have been probed. Highly active amorphous molybdenum sulfide particles can also be prepared

  1. Mercury emission monitoring on municipal waste combustion

    International Nuclear Information System (INIS)

    Braun, H.; Gerig, A.

    1991-01-01

    In waste incineration, mercury is the only heavy metal to be released as a gas, mostly as mercury(II) chloride, because of its high volatility. Continuous emission monitoring is possible only when mercury occurs in its elemental form. This paper reports on various possibilities of converting Hg(II) into Hg(0) that has been studied and tested on a laboratory scale and in the TAMARA refuse incineration pilot facility. Continuous mercury emission measurement appears to be possible, provided mercury is converted in the flue gas condensate precipitated. The measuring results obtained on two municipal solid waste and on one sewage treatment sludge incineration plants show that the mercury monitor is a highly sensitive and selective continuously working instrument for mercury emission monitoring

  2. Fate of mercury in the Arctic (FOMA)

    DEFF Research Database (Denmark)

    Skov, H.; Christensen, J.; Asmund, G.

    This report is the final reporting of the project FONA, funded by the Danish Environmental Protection Agency with means from the MIKA/DANCEA funds for Environmental Support to the Arctic Region. The aim of the project is to study the intercompartment mercury transport chain in the arctic area. From...... atmospheric deposition of mercury on sea surfaces to uptake in marine organisms, bio-accumulation, and finally mercury levels in mammals. The studies in the project are focused on the behaviour of mercury during the spring period where special phenomena lead to an enhanced deposition of mercury in the Arctic...... environment, at a time where the marine ecosystem is particularly active. The studies also include a comprehensive time trend study of mercury in top carnivore species. Each of these studies contributes towards establishing the knowledge necessary to develop a general model for transport and uptake of mercury...

  3. Occupational exposure to hydrogen sulfide: management of hydrogen sulfide exposure victims (Preprint No. SA-5)

    International Nuclear Information System (INIS)

    Srivastava, P.P.

    1989-04-01

    National Institute of Occupational Safety and Health, U.S.A. has listed 73 industries with potential exposure to hydrogen sulphide. Though the toxicity of hydrogen sulfide is known to mankind since the beginning of seventeenth century the exact mode of its toxicity and effective therapeutic regimen remains unclear as yet. This paper presents current thoughts on the toxicity of this substance and a discussion on the role of various antidotes used in H 2 S poisoning. (autho r)

  4. Photocatalytic degradation of 2-phenethyl-2-chloroethyl sulfide in liquid and gas phases.

    Science.gov (United States)

    Vorontsov, Alexandre V; Panchenko, Alexander A; Savinov, Evgueni N; Lion, Claude; Smirniotis, Panagiotis G

    2002-12-01

    This work explores the ability of photocatalysis to decontaminate water and air from chemical warfare agent mustard using its simulant 2-phenethyl 2-chloroethyl sulfide (PECES). PECES like mustard slowly dissolves in water with hydrolysis, forming 2-phenethyl 2-hydroxyethyl sulfide (PEHES). Irradiation of TiO2 suspension containing PECES with the unfiltered light of a mercury lamp (lambda > or = 254 nm) decomposed all PECES mostly via photolysis. Reaction under filtered light (lambda > 300 nm) proceeds mainly photocatalytically and requires longer time. Sulfur from starting PECES is completely transformed into sulfuric acid at the end of the reaction. Detected volatile, nonvolatile, surface products, and the suggested scheme of degradation are reported. The main volatile products are styrene and benzaldehyde, nonvolatile--hydroxylated PEHES, surface--2-phenethyl disulfide. Photolysis of PECES produced the same set of volatile products as photocatalysis. Photocatalytic degradation of gaseous PECES in air results in its mineralization but is accompanied by TiO2 deactivation. The highest rate of mineralization with minimum deactivation was observed at about room temperature and a water concentration of 27,500 ppm. No gaseous products except CO2 were detected. The main extracted surface product was styrene. It was concluded that PECES photocatalytic degradation proceeds mainly via C-S bond cleavage and further oxidation of the products. Hydrolysis of the C-S bond was detected only in gas-phase photocatalytic degradation. The quantum efficiency of gas-phase degradation (0.28%) was much higher than that of liquid-phase degradation (0.008%). The results demonstrate the ability of photocatalysis to decontaminate an aqueous and especially an air environment

  5. Multiplexed electrochemical immunoassay of biomarkers using metal sulfide quantum dot nanolabels and trifunctionalized magnetic beads.

    Science.gov (United States)

    Tang, Dianping; Hou, Li; Niessner, Reinhard; Xu, Mingdi; Gao, Zhuangqiang; Knopp, Dietmar

    2013-08-15

    A novel multiplexed stripping voltammetric immunoassay protocol was designed for the simultaneous detection of multiple biomarkers (CA 125, CA 15-3, and CA 19-9 used as models) using PAMAM dendrimer-metal sulfide quantum dot (QD) nanolabels as distinguishable signal tags and trifunctionalized magnetic beads as an immunosensing probe. The probe was prepared by means of co-immobilization of primary monoclonal anti-CA 125, anti-CA 15-3 and anti-CA 19-9 antibodies on a single magnetic bead. The PAMAM dendrimer-metal sulfide QD nanolabels containing CdS, ZnS and PbS were synthesized by using in situ synthesis method, which were utilized for the labeling of polyclonal rabbit anti-CA 125, anti-CA 15-3 and anti-CA 19-9 detection antibodies, respectively. A sandwich-type immunoassay format was adopted for the simultaneous determination of target biomarkers in a low-binding microtiter plate. The subsequent anodic stripping voltammetric analysis of cadmium, zinc, and lead components released by acid from the corresponding QD nanolabels was conducted at an in situ prepared mercury film electrode based on the difference of peak potentials. Experimental results indicated that the multiplexed immunoassay enabled the simultaneous detection of three cancer biomarkers in a single run with wide dynamic ranges of 0.01-50 U mL(-1) and detection limits (LODs) of 0.005 U mL(-1). Intra-assay and inter-assay coefficients of variation (CVs) were less than 7.2% and 10.4%, respectively. No significant differences at the 0.05 significance level were encountered in the analysis of 10 clinical serum specimens between the multiplexed immunoassay and a commercially available enzyme-linked immunosorbent assay (ELISA). Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Mercury in the environment : a review

    International Nuclear Information System (INIS)

    Goodarzi, F.

    2000-01-01

    Both geogenic and anthropogenic sources are responsible for the input of mercury into the environment. However, mercury comes mostly from geogenic sources and is found naturally in air, water and soil. Crustal degassing results in emission of mercury into the atmosphere. Mercury in water and soil is due mostly to input from sedimentary rocks. Mercury in lake sediments is related mainly to input by country rock and anthropogenic activities such as agriculture. The mercury content of coal is similar to or less than the amount found in the earths crust. Natural charcoal is also able to capture mercury at low temperature combustion. The amount of mercury emitted from the stack of coal-fired power plants is related to the nature of the milled coal and its mineralogical and elemental content. Mercury emissions originating from the combustion of coal from electric utility power plants are considered to be among the greatest contributors to global mercury air emissions. In order to quantify the impact the electric power industry has on the environment, information regarding mercury concentrations in coal and their speciation is needed. For this reason the author examined the behaviour of mercury in three coal samples ashed at increasing temperatures. Mercury removal from coal-fired power plants ranges from 10 to 50 per cent by fabric filters and 20 to 95 per cent by FGD systems. This data will help in regulating emissions of hazardous air pollutants from electric utility steam generating units and will potentially provide insight into the industry's contribution to the global mercury burden. 50 refs

  7. Mercury biogeochemistry: Paradigm shifts, outstanding issues and research needs

    Science.gov (United States)

    Sonke, Jeroen E.; Heimbürger, Lars-Eric; Dommergue, Aurélien

    2013-05-01

    Half a century of mercury research has provided scientists and policy makers with a detailed understanding of mercury toxicology, biogeochemical cycling and past and future impacts on human exposure. The complexity of the global biogeochemical mercury cycle has led to repeated and ongoing paradigm shifts in numerous mercury-related disciplines and outstanding questions remain. In this review, we highlight some of the paradigm shifts and questions on mercury toxicity, the risks and benefits of seafood consumption, the source of mercury in seafood, and the Arctic mercury cycle. We see a continued need for research on mercury toxicology and epidemiology, for marine mercury dynamics and ecology, and for a closer collaboration between observational mercury science and mercury modeling in general. As anthropogenic mercury emissions are closely tied to the energy cycle (in particular coal combustion), mercury exposure to humans and wildlife are likely to persist unless drastic emission reductions are put in place.

  8. Mercury erosion experiments for spallation target system

    International Nuclear Information System (INIS)

    Kinoshita, Hidetaka; Kaminaga, Masanori; Haga, Katsuhiro; Hino, Ryutaro

    2003-01-01

    The Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting a plan to construct the spallation neutron source at the Tokai Research Establishment, JAERI, under the High-Intensity Proton Accelerator Project (J-PARC). A mercury circulation system has been designed so as to supply mercury to the target stably under the rated flow rate of 41 m 3 /hr. Then, it was necessary to confirm a mercury pump performance from the viewpoint of making the mercury circulation system feasible, and more, to investigate erosion rate under the mercury flow as well as an amount of mercury remained on the surface after drain from the viewpoints of mechanical strength relating to the lifetime and remote handling of mercury components. The mercury pump performance was tested under the mercury flow conditions by using an experimental gear pump, which had almost the same structure as a practical mercury pump to be expected in the mercury circulation system, and the erosion rates in a mercury pipeline as well as the amount of mercury remained on the surface were also investigated. The discharged flow rates of the experimental gear pump increased linearly with the rotation speed, so that the gear pump would work as the flow meter. Erosion rates obtained under the mercury velocity less than 1.6 m/s was found to be so small that decrease of pipeline wall thickness would be 390 μm after 30-year operation under the rated mercury velocity of 0.7 m/s. For the amount of remaining mercury on the pipeline, remaining rates of weight and volume were estimated at 50.7 g/m 2 and 3.74 Hg-cm 3 /m 2 , respectively. Applying these remaining rates of weight and volume to the mercury target, the remaining mercury was estimated at about 106.5 g and 7.9 cm 3 . Radioactivity of this remaining mercury volume was found to be three-order lower than that of the target casing. (author)

  9. Azo dye decolorization assisted by chemical and biogenic sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Prato-Garcia, Dorian [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico); Cervantes, Francisco J. [División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa de San José 2055, San Luis Potosí 78216 (Mexico); Buitrón, Germán, E-mail: gbuitronm@ii.unam.mx [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico)

    2013-04-15

    Highlights: ► Azo dyes were reduced efficiently by chemical and biogenic sulfide. ► Biogenic sulfide was more efficient than chemical sulfide. ► There was no competition between dyes and sulfate for reducing equivalents. ► Aromatic amines barely affected the sulfate-reducing process. -- Abstract: The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was more efficient than chemical sulfide for decolorizing the azo dyes. The performance of sulfate-reducing bacteria in attached-growth sequencing batch reactors suggested the absence of competition between the studied azo dyes and the sulfate-reducing process for the reducing equivalents. Additionally, the presence of chemical reduction by-products had an almost negligible effect on the sulfate removal rate, which was nearly constant (94%) after azo dye injection.

  10. Synthesis and characterization of metal sulfide clusters for toxicological studies.

    Science.gov (United States)

    Bowles, L C; Bell, Russell A; Ernste, Michael J; Kramer, James R; Manolopoulos, Helen; Ogden, Nancy

    2002-04-01

    Zinc sulfide clusters were synthesized and characterized at low micromolar concentrations to assess the effect of metal-sulfide ligands on metal toxicity to aquatic organisms in oxic environments. Recommended preparation times are greater than 2 h initial reaction of equimolar sodium sulfide and zinc nitrate, followed by oxic aeration for 3 d. Ionic strength, pH, and anoxic stabilization time were found to be relatively unimportant in controlling the final yield. Adsorptive losses of zinc sulfide (ZnS) clusters to surfaces, however, were significant for a variety of vessel materials and membrane filters. Ionic strength and pH were found to be important factors controlling the extent of adsorptive losses with minimal loss for pHs greater than 9 and for soft waters. The Ag(I), Cu(II), and Hg(II) as metal sulfides completely suppress the analysis of sulfide, whereas Pb(II), Mn(II), and Co(II) partially suppress the analysis of sulfide by the methylene blue technique. Ultraviolet and fluorescence spectra are shown for synthesized ZnS clusters.

  11. Sulfidation behavior and mechanism of zinc silicate roasted with pyrite

    Science.gov (United States)

    Ke, Yong; Peng, Ning; Xue, Ke; Min, Xiaobo; Chai, Liyuan; Pan, Qinglin; Liang, Yanjie; Xiao, Ruiyang; Wang, Yunyan; Tang, Chongjian; Liu, Hui

    2018-03-01

    Sulfidation roasting followed by flotation is widely known as a possible generic technology for enriching valuable metals in low-grade Zn-Pb oxide ores. Zn2SiO4 is the primary Zn phase in willemite. Zn4Si2O7(OH)2(H2O), the main Zn phase in hemimorphite, transforms into Zn2SiO4 at temperatures above 600 °C. To enrich the Zn in willemite and hemimorphite, the Zn species should first be converted to ZnS. Therefore, a thorough understanding of the sulfidation reaction of Zn2SiO4 during roasting with pyrite is of vital important. In this study, the sulfidation behavior and reaction mechanisms of a Zn2SiO4-pyrite roasting system were determined using HSC 5.0 software, TG-FTIR spectroscopy, XRD, XPS and SEM-EDS. The results indicate that the sulfidation process can be divided into three steps: the decomposition of pyrite and formation of a sulfur-rich environment, the sulfur-induced migration of O2- and transformation of sulfur vapor, and the sulfidation reaction via oxygen-sulfur exchange. During the sulfidation roasting process, pyrite was converted to loose and porous Fe3O4, whereas Zn2SiO4 was transformed into ZnS and SiO2 in situ. These findings provide theoretical support for controlling the sulfidation roasting process of willemite and hemimorphite.

  12. Sulfidic vapor phase catalysts, especially tungsten sulfide, in industrial coal hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Pier, M.

    1943-01-01

    The historical development of high-pressure processes of the I. G. Farbenindustrie, from ammonia through methanol and gasoline, and the special case of gasoline production with a fixed-bed catalyst (tungsten sulfide) were discussed. The preparation, properties, and uses of this versatile catalyst were discussed, but it was emphasized that with the sotrmy development of the process, a condition which still existed at the time of this report, and with a great number of practical problems to solve, no extensive study of basic facts had ben possible. This tungsten sulfide catalyst was an especially active vapor-phase catalyst which operated at lower temperatures than the molybdenum catalysts formerly used. It also permitted higher thruputs, even with the oils from bituminous coal that were difficult to split. For certain uses, such as the improvement of the antiknock properties or the saving in tungsten, it was strongly diluted. Studies on using up sulfur in the tungsten sulfide catalyst were in progress at this time and showed there was practically no reduction of it under the conditions of hydrogenation under pressure as long as the raw material contained sulfur.

  13. On the pelletizing of sulfide molybdenite concentrate

    International Nuclear Information System (INIS)

    Palant, A.A.

    2007-01-01

    Investigation results are discussed on the process of pelletizing with the use of various binders (water, syrup, sulfite-alcoholic residue and bentonite) for flotation sulfide molybdenite concentrate (∼84 % MoS 2 ) of the Mongolian deposit. It is established that with the use of syrup rather strong pellets (>300 g/p) of desired size (2-3 mm) can be obtained at a binder flowrate of 1 kg per 100 kg of concentrate. The main advantage of using syrup instead of bentonite lies in the fact that in this instance no depletion of a molybdenum calcine obtained by oxidizing roasting of raw ore takes place due to syrup complete burning out. This affects positively subsequent hydrometallurgical conversion because of decreasing molybdenum losses with waste cakes [ru

  14. Modulated structure calculated for superconducting hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, Arnab; Tse, John S.; Yao, Yansun [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, SK (Canada)

    2017-09-11

    Compression of hydrogen sulfide using first principles metadynamics and molecular dynamics calculations revealed a modulated structure with high proton mobility which exhibits a diffraction pattern matching well with experiment. The structure consists of a sublattice of rectangular meandering SH{sup -} chains and molecular-like H{sub 3}S{sup +} stacked alternately in tetragonal and cubic slabs forming a long-period modulation. The novel structure offers a new perspective on the possible origin of the superconductivity at very high temperatures in which the conducting electrons in the SH chains are perturbed by the fluxional motions of the H{sub 3}S resulting in strong electron-phonon coupling. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Touchstones and mercury at Hedeby

    Czech Academy of Sciences Publication Activity Database

    Ježek, Martin; Holub, M.

    2014-01-01

    Roč. 89, č. 1 (2014), s. 193-204 ISSN 0079-4848 Institutional support: RVO:67985912 Keywords : Hedeby * Viking Age * grave goods * touchstone * precious metal * mercury * chemical microanalysis * archaeometallurgy Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 0.278, year: 2014

  16. PERCEPTION OF MERCURY RISK INFORMATION

    Science.gov (United States)

    Approximately 8% of American women have blood Mercury levels exceeding the EPA reference dose (a dose below which symptoms would be unlikely). The children of these women are at risk of neurological deficits (lower IQ scores) primarily because of the mother's consumption of conta...

  17. A downstream voyage with mercury

    Science.gov (United States)

    Heinz, Gary

    2016-01-01

    Retrospective essay for the Bulletin of Environmental Contamination and Toxicology.As I look back on my paper, “Effects of Low Dietary Levels of Methyl Mercury on Mallard Reproduction,” published in 1974 in the Bulletin of Environmental Contamination and Toxicology, a thought sticks in my mind. I realize just how much my mercury research was not unlike a leaf in a stream, carried this way and that, sometimes stalled in an eddy, restarted, and carried downstream at a pace and path that was not completely under my control. I was hired in 1969 by the Patuxent Wildlife Research Center to study the effects of environmental pollutants on the behavior of wildlife. A colleague was conducting a study on the reproductive effects of methylmercury on mallards (Anas platyrhynchos), and he offered to give me some of the ducklings. I conducted a pilot study, testing how readily ducklings approached a tape-recorded maternal call. Sample sizes were small, but the results suggested that ducklings from mercury-treated parents behaved differently than controls. That’s how I got into mercury research—pretty much by chance.

  18. Venus and Mercury as Planets

    Science.gov (United States)

    1974-01-01

    A general evolutionary history of the solar planetary system is given. The previously observed characteristics of Venus and Mercury (i.e. length of day, solar orbit, temperature) are discussed. The role of the Mariner 10 space probe in gathering scientific information on the two planets is briefly described.

  19. Venus and Mercury as planets

    International Nuclear Information System (INIS)

    1974-01-01

    A general evolutionary history of the solar planetary system is given. The previously observed characteristics of Venus and Mercury (i.e. length of day, solar orbit, temperature) are discussed. The role of the Mariner 10 space probe in gathering scientific information on the two planets is briefly described

  20. 76 FR 75446 - Amendment of Class E Airspace; Mercury, NV

    Science.gov (United States)

    2011-12-02

    ...-0894; Airspace Docket No. 11-AWP-14] Amendment of Class E Airspace; Mercury, NV AGENCY: Federal... Mercury, Desert Rock Airport, Mercury, NV. Decommissioning of the Mercury Non-Directional Beacon (NDB) at Mercury, Desert Rock Airport has made this action necessary for the safety and management of Instrument...

  1. 75 FR 8889 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

    Science.gov (United States)

    2010-02-26

    ... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection... for hydrogen sulfide (Chemical Abstracts Service Number (CAS No.) 7783-06-4). Hydrogen sulfide was... requirements for hydrogen sulfide in order to evaluate issues brought to the Agency's attention after...

  2. Thermoelectric properties of non-stoichiometric lanthanum sulfides

    International Nuclear Information System (INIS)

    Shapiro, E.; Danielson, L.R.

    1983-01-01

    The lanthanum sulfides are promising candidate materials for high-efficiency thermoelectric applications at temperatures up to 1300 0 C. The nonstoichiometric lanthanum sulfides (LaS /SUB x/ , where 1.33 2 //rho/ can be chosen. The thermal conductivity remains approximately constant with stoichiometry, so a material with an optimum value of α 2 //rho/ should possess the optimum figure-of-merit. Data for the Seebeck coefficient and electrical resistivity of non-stoichiometric lanthanum sulfides is presented, together with structural properties of these materials

  3. Sulfide Oxidation in the Anoxic Black-Sea Chemocline

    DEFF Research Database (Denmark)

    JØRGENSEN, BB; FOSSING, H.; WIRSEN, CO

    1991-01-01

    per day, occurred in anoxic water at the top of the sulfide zone concurrent with the highest rates of dark CO2 assimilation. The main soluble oxidized products of sulfide were thiosulfate (68-82%) and sulfate. Indirect evidence was presented for the formation of elemental sulfur which accumulated...... that the measured H2S oxidation rates were 4-fold higher than could be explained by the downward flux of organic carbon and too high to balance the availability of electron acceptors such as oxidized iron or manganese. A nitrate maximum at the lower boundary of the O2 zone did not extend down to the sulfide zone....

  4. Iron sulfide corrosion in the 700 atm. liquid phase preheater

    Energy Technology Data Exchange (ETDEWEB)

    Donath, E.; Nonnenmacher, H.

    1943-07-28

    Equilibrium calculations gave lower bounds on partial pressure of hydrogen sulfide within a 500 atm. hydrogen gas stream, below which no corrosion of the steel tube walls would occur. AT 450/sup 0/C the lower bound was 0.5 atm., whereas at 500/sup 0/C the lower bound was 0.8 atm. However, in most plants, the hydrogen sulfide partial pressure exceeded values, so corrosion by formation of iron sulfide did usually occur. It was estimated that the corrosion reaction rate at 500/sup 0/C was about twice what it was at 450/sup 0/C.

  5. Conspicuous veils formed by vibrioid bacteria on sulfidic marine sediment

    DEFF Research Database (Denmark)

    Thar, Roland Matthias; Kühl, Michael

    2002-01-01

    We describe the morphology and behavior of a hitherto unknown bacterial species that forms conspicuous veils (typical dimensions, 30 by 30 mm) on sulfidic marine sediment. The new bacteria were enriched on complex sulfidic medium within a benthic gradient chamber in oxygen-sulfide countergradients......, but the bacteria have so far not been isolated in pure culture, and a detailed characterization of their metabolism is still lacking. The bacteria are colorless, gram-negative, and vibrioid-shaped (1.3- to 2.5- by 4- to 10-µm) cells that multiply by binary division and contain several spherical inclusions of poly...

  6. The Plasma Environment at Mercury

    Science.gov (United States)

    Raines, James M.; Gershman, Daniel J.; Zurbuchen, Thomas H.; Gloeckler, George; Slavin, James A.; Anderson, Brian J.; Korth, Haje; Krimigis, Stamatios M.; Killen, Rosemary M.; Sarantos, Menalos; hide

    2011-01-01

    Mercury is the least explored terrestrial planet, and the one subjected to the highest flux of solar radiation in the heliosphere. Its highly dynamic, miniature magnetosphere contains ions from the exosphere and solar wind, and at times may allow solar wind ions to directly impact the planet's surface. Together these features create a plasma environment that shares many features with, but is nonetheless very different from, that of Earth. The first in situ measurements of plasma ions in the Mercury space environment were made only recently, by the Fast Imaging Plasma Spectrometer (FIPS) during the MESSENGER spacecraft's three flybys of the planet in 2008-2009 as the probe was en route to insertion into orbit about Mercury earlier this year. Here. we present analysis of flyby and early orbital mission data with novel techniques that address the particular challenges inherent in these measurements. First. spacecraft structures and sensor orientation limit the FIPS field of view and allow only partial sampling of velocity distribution functions. We use a software model of FIPS sampling in velocity space to explore these effects and recover bulk parameters under certain assumptions. Second, the low densities found in the Mercury magnetosphere result in a relatively low signal-to-noise ratio for many ions. To address this issue, we apply a kernel density spread function to guide removal of background counts according to a background-signature probability map. We then assign individual counts to particular ion species with a time-of-flight forward model, taking into account energy losses in the carbon foil and other physical behavior of ions within the instrument. Using these methods, we have derived bulk plasma properties and heavy ion composition and evaluated them in the context of the Mercury magnetosphere.

  7. Micro-aeration for hydrogen sulfide removal from biogas

    Science.gov (United States)

    Duangmanee, Thanapong

    The presence of sulfur compounds (e.g. protein, sulfate, thiosulfate, sulfite, etc.) in the feed stream generates highly corrosive and odorous hydrogen sulfide during anaerobic digestion. The high sulfide level in the biogas stream is not only poisonous to many novel metal catalysts employed in thermo-catalytic processes but also reduces the quality of methane to produce renewable energy. This study used an innovative, low-maintenance, low-cost biological sulfide removal technology to remove sulfides simultaneously from both gas and liquid phase. ORP (Oxidation-Reduction-Potential) was used as the controlling parameter to precisely regulate air injection to the sulfide oxidizing unit (SOU). The microaeration technique provided just enough oxygen to partially oxidize sulfides to elemental sulfur without inhibiting methanogenesis. The SOU was equipped with a diffuser at the bottom for the dispersion of sulfide-laden biogas and injected air throughout the column. The SOU can be operated as a standalone unit or coupled with an anaerobic digester to simultaneously remove sulfide from the biogas and effluent. The integrated system was capable of reducing hydrogen sulfide in biogas from 2,450 to less than 2 ppmV with minimal sulfate production at the highest available sulfide loading rate of 0.24 kg/m3-day. More than 98% of sulfide removed was recovered as elemental sulfur. However, the standalone SOU was able to operate at high hydrogen sulfide loading of 1.46 kg/m 3-day at inlet sulfide concentration of 3000 ppmV and reduce the off-gas hydrogen sulfide concentrations to less than 10 ppmV. The experiment also revealed that the ORP controlled aeration was sensitive enough to prevent oxygen overdosing (dampening effect) during unexpected surges of aeration. Using generalized linear regression, a model predicting output H2S concentration based on input H2S concentrations, SOU medium heights, and biogas flow rates, was derived. With 95% confidence, output H2S concentration

  8. Chemical form matters: differential accumulation of mercury following inorganic and organic mercury exposures in zebrafish larvae.

    Science.gov (United States)

    Korbas, Malgorzata; Macdonald, Tracy C; Pickering, Ingrid J; George, Graham N; Krone, Patrick H

    2012-02-17

    Mercury, one of the most toxic elements, exists in various chemical forms each with different toxicities and health implications. Some methylated mercury forms, one of which exists in fish and other seafood products, pose a potential threat, especially during embryonic and early postnatal development. Despite global concerns, little is known about the mechanisms underlying transport and toxicity of different mercury species. To investigate the impact of different mercury chemical forms on vertebrate development, we have successfully combined the zebrafish, a well-established developmental biology model system, with synchrotron-based X-ray fluorescence imaging. Our work revealed substantial differences in tissue-specific accumulation patterns of mercury in zebrafish larvae exposed to four different mercury formulations in water. Methylmercury species not only resulted in overall higher mercury burdens but also targeted different cells and tissues than their inorganic counterparts, thus revealing a significant role of speciation in cellular and molecular targeting and mercury sequestration. For methylmercury species, the highest mercury concentrations were in the eye lens epithelial cells, independent of the formulation ligand (chloride versusl-cysteine). For inorganic mercury species, in absence of l-cysteine, the olfactory epithelium and kidney accumulated the greatest amounts of mercury. However, with l-cysteine present in the treatment solution, mercuric bis-l-cysteineate species dominated the treatment, significantly decreasing uptake. Our results clearly demonstrate that the common differentiation between organic and inorganic mercury is not sufficient to determine the toxicity of various mercury species.

  9. Chemical Form Matters: Differential Accumulation of Mercury Following Inorganic and Organic Mercury Exposures in Zebrafish Larvae

    Energy Technology Data Exchange (ETDEWEB)

    Korbas, Malgorzata; MacDonald, Tracy C.; Pickering, Ingrid J.; George, Graham N.; Krone, Patrick H. (Saskatchewan)

    2013-04-08

    Mercury, one of the most toxic elements, exists in various chemical forms each with different toxicities and health implications. Some methylated mercury forms, one of which exists in fish and other seafood products, pose a potential threat, especially during embryonic and early postnatal development. Despite global concerns, little is known about the mechanisms underlying transport and toxicity of different mercury species. To investigate the impact of different mercury chemical forms on vertebrate development, we have successfully combined the zebrafish, a well-established developmental biology model system, with synchrotron-based X-ray fluorescence imaging. Our work revealed substantial differences in tissue-specific accumulation patterns of mercury in zebrafish larvae exposed to four different mercury formulations in water. Methylmercury species not only resulted in overall higher mercury burdens but also targeted different cells and tissues than their inorganic counterparts, thus revealing a significant role of speciation in cellular and molecular targeting and mercury sequestration. For methylmercury species, the highest mercury concentrations were in the eye lens epithelial cells, independent of the formulation ligand (chloride versus L-cysteine). For inorganic mercury species, in absence of L-cysteine, the olfactory epithelium and kidney accumulated the greatest amounts of mercury. However, with L-cysteine present in the treatment solution, mercuric bis-L-cysteineate species dominated the treatment, significantly decreasing uptake. Our results clearly demonstrate that the common differentiation between organic and inorganic mercury is not sufficient to determine the toxicity of various mercury species.

  10. Molecular Scale Dissolved Organic Matter Interactions Impact Mercury Bioavailability for Uptake and Methylation by Sulfate-Reducing Bacteria

    Science.gov (United States)

    Moreau, J. W.; Krabbenhoft, D. P.

    2008-12-01

    Biogeochemical factors such as dissolved natural organic matter (DOM) type and abundance may play a major role in governing the bioavailability of aqueous Hg(II) for uptake and methylation by sulfate-reducing bacteria (SRB). MeHg production correlates in some cases with predicted dominance of hydrophobic, neutrally-charged, aqueous HgS. This species is thought to interact strongly with DOM via hydrophobic attractions. Field and laboratory observations suggest that DOM promotes methylation. We therefore hypothesized that DOM isolates of differing (well-characterized) functional compositions (e.g., hydrophobic versus hydrophilic) could variably enhance bacterial methylation. Methylation assays using Desulfobulbus propionicus 1pr3 in fermentative growth were performed using a mercury isotope tracer applied at concentrations of roughly 100 ng/L. The tracer was pre-equilibrated with 5-10 uM aqueous sulfide and approximately 40 mg/L of either hydrophobic or hydrophilic DOM prior to inoculation. Results showed roughly 1-3% tracer methylation in both hydrophobic DOM+ and DOM- cultures. However, a similar amount of non- tracer (background) mercury associated with the hydrophobic DOM fraction was also methylated. Preliminary results suggested that pre-equilibration of the isotope tracer for up to one month with hydrophobic-fraction humic acids resulted in a roughly 2-3X increase in the quantity and rate of methylation, indicating an important role for aging on DOM in Hg bioavailability. Mercury-sulfide-DOM equilibration products were investigated with synchrotron-based x-ray fluorescence spectroscopy (EXAFS) at liquid nitrogen temperatures. Hg L(III)-edge spectra from resin-concentrated Hg-S-DOM equilibration products exhibited high similarity to a metacinnabar-like conformation. Culturing and EXAFS results, taken together, suggest that nanophase metacinnabar, "packaged" in DOM, could have been the bioavailable form of Hg(II) in culturing experiments. Further experiments

  11. Mercury emission from crematories in Japan

    Directory of Open Access Journals (Sweden)

    M. Takaoka

    2010-04-01

    Full Text Available Anthropogenic sources of mercury emissions have a significant impact on global pollution. Therefore, finding uncharacterised sources and assessing the emissions from these sources are important. However, limited data are available worldwide on mercury emissions from crematories. In Japan, 99.9% of dead bodies are cremated, which is the highest percentage in the world, and more than 1600 crematories are in operation. We thus focused on emissions from crematories in Japan. The number of targeted facilities was seven, and we used continuous emission monitoring to measure the mercury concentrations and investigate mercury behaviour. The total mercury concentrations in stack gases were a few μg/Nm3 (normal cubic meters. Considering the time profile of mercury and its species in cremations, the findings confirmed that the mercury in stack gas originated from dental amalgam. The amount of mercury emissions was calculated using the total concentration and gas flow rate. Furthermore, the annual amount of mercury emission from crematories in Japan was estimated by using the total number of corpses. The emission amount was considerably lower than that estimated in the United Kingdom. From statistical analyses on population demographics and measurements, future total emissions from crematories were also predicted. As a result, the amount of mercury emitted by crematories will likely increase by 2.6-fold from 2007 to 2037.

  12. Environmental Mercury and Its Toxic Effects

    Directory of Open Access Journals (Sweden)

    Kevin M. Rice

    2014-03-01

    Full Text Available Mercury exists naturally and as a man-made contaminant. The release of processed mercury can lead to a progressive increase in the amount of atmospheric mercury, which enters the atmospheric-soil-water distribution cycles where it can remain in circulation for years. Mercury poisoning is the result of exposure to mercury or mercury compounds resulting in various toxic effects depend on its chemical form and route of exposure. The major route of human exposure to methylmercury (MeHg is largely through eating contaminated fish, seafood, and wildlife which have been exposed to mercury through ingestion of contaminated lower organisms. MeHg toxicity is associated with nervous system damage in adults and impaired neurological development in infants and children. Ingested mercury may undergo bioaccumulation leading to progressive increases in body burdens. This review addresses the systemic pathophysiology of individual organ systems associated with mercury poisoning. Mercury has profound cellular, cardiovascular, hematological, pulmonary, renal, immunological, neurological, endocrine, reproductive, and embryonic toxicological effects.

  13. Mercury emissions from municipal solid waste combustors

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    This report examines emissions of mercury (Hg) from municipal solid waste (MSW) combustion in the United States (US). It is projected that total annual nationwide MSW combustor emissions of mercury could decrease from about 97 tonnes (1989 baseline uncontrolled emissions) to less than about 4 tonnes in the year 2000. This represents approximately a 95 percent reduction in the amount of mercury emitted from combusted MSW compared to the 1989 mercury emissions baseline. The likelihood that routinely achievable mercury emissions removal efficiencies of about 80 percent or more can be assured; it is estimated that MSW combustors in the US could prove to be a comparatively minor source of mercury emissions after about 1995. This forecast assumes that diligent measures to control mercury emissions, such as via use of supplemental control technologies (e.g., carbon adsorption), are generally employed at that time. However, no present consensus was found that such emissions control measures can be implemented industry-wide in the US within this time frame. Although the availability of technology is apparently not a limiting factor, practical implementation of necessary control technology may be limited by administrative constraints and other considerations (e.g., planning, budgeting, regulatory compliance requirements, etc.). These projections assume that: (a) about 80 percent mercury emissions reduction control efficiency is achieved with air pollution control equipment likely to be employed by that time; (b) most cylinder-shaped mercury-zinc (CSMZ) batteries used in hospital applications can be prevented from being disposed into the MSW stream or are replaced with alternative batteries that do not contain mercury; and (c) either the amount of mercury used in fluorescent lamps is decreased to an industry-wide average of about 27 milligrams of mercury per lamp or extensive diversion from the MSW stream of fluorescent lamps that contain mercury is accomplished.

  14. Mercury exposure from interior latex paint.

    Science.gov (United States)

    Agocs, M M; Etzel, R A; Parrish, R G; Paschal, D C; Campagna, P R; Cohen, D S; Kilbourne, E M; Hesse, J L

    1990-10-18

    Many paint companies have used phenylmercuric acetate as a preservative to prolong the shelf life of interior latex paint. In August 1989, acrodynia, a form of mercury poisoning, occurred in a child exposed to paint fumes in a home recently painted with a brand containing 4.7 mmol of mercury per liter (at that time the Environmental Protection Agency's recommended limit was 1.5 mmol or less per liter). To determine whether the recent use of that brand of paint containing phenylmercuric acetate was associated with elevated indoor-air and urinary mercury concentrations, we studied 74 "exposed" persons living in 19 homes recently painted with the brand and 28 "unexposed" persons living in 10 homes not recently painted with paint containing mercury. The paint samples from the homes of exposed persons contained a median of 3.8 mmol of mercury per liter, and air samples from the homes had a median mercury content of 10.0 nmol per cubic meter (range, less than 0.5 to 49.9). No mercury was detected in paint or air samples from the homes of unexposed persons. The median urinary mercury concentration was higher in the exposed persons (4.7 nmol of mercury per millimole of creatinine; range, 1.4 to 66.5) than in the unexposed persons (1.1 nmol per millimole; range, 0.02 to 3.9; P less than 0.001). Urinary mercury concentrations within the range that we found in exposed persons have been associated with symptomatic mercury poisoning. We found that potentially hazardous exposure to mercury had occurred among persons whose homes were painted with a brand of paint containing mercury at concentrations approximately 2 1/2 times the Environmental Protection Agency's recommended limit.

  15. Co-settling of Chromite and Sulfide Melt Droplets and Trace Element Partitioning between Sulfide and Silicate Melts

    Science.gov (United States)

    Manoochehri, S.; Schmidt, M. W.; Guenther, D.

    2013-12-01

    Gravitational settling of immiscible, dense sulfide melt droplets together with other cumulate phases such as chromite, combined with downward percolation of these droplets through a cumulate pile, is thought to be one of the possible processes leading to the formation of PGE rich sulfide deposits in layered mafic intrusions. Furthermore some chromitite seams in the Merensky Reef (Bushveld Complex) are considered to be acting as a filter or barrier for further downward percolation of sulfide melts into footwall layers. To investigate the feasibility of such mechanical processes and to study the partitioning behavior of 50 elements including transition metals and REEs (but not PGEs) between a silicate and a sulfide melt, two separate series of high temperature (1250-1380 °C) centrifuge-assisted experiments at 1000 g, 0.4-0.6 GPa were conducted. A synthetic silicate glass with a composition representative of the parental magma of the Bushveld Complex (~ 55 wt% SiO2) was mixed with pure FeS powder. For the first series of experiments, 15 or 25 wt% natural chromite with average grain sizes of ~ 5 or 31 μm were added to a mixture of silicate glass and FeS (10 wt%) adding 1 wt% water. For the second series, a mixture of the same glass and FeS was doped with 50 trace elements. These mixtures were first statically equilibrated and then centrifuged. In the first experimental series, sulfide melt droplets settled together with, but did not segregate from chromite grains even after centrifugation at 1000 g for 12 hours. A change in initial chromite grain size and proportions didn't have any effect on segregation. Without chromite, the starting mixture resulted in the formation of large sulfide melt pools together with finer droplets still disseminated through the silicate glass and both at the bottom of the capsule. The incomplete segregation of sulfide melt is interpreted as being due to high interfacial energies between sulfide and silicate melts/crystals which hinder

  16. Damage of Metal Structures Under the Action of Hydrogen Sulfide Containing Environments

    Science.gov (United States)

    Kushnarenko, V. M.; Uzyakov, R. N.; Repyakh, V. S.

    2018-01-01

    The effect of hydrogen sulfide containing environments, stress-strain states, stress concentration and external actions on the hydrogen sulfide cracking of steels is considered. Examples of typical and atypical action of hydrogen sulfide containing environments on carbon and stainless steels are presented. The factors responsible for hydrogen sulfide cracking are determined. Recommendations are given on design and production of equipment contacting hydrogen sulfide environments.

  17. RECOVERY OF MERCURY FROM CONTAMINATED LIQUID WASTES

    Energy Technology Data Exchange (ETDEWEB)

    Robin M. Stewart

    1999-09-29

    Mercury was widely used in U.S. Department of Energy (DOE) weapons facilities, resulting in a broad range of mercury-contaminated wastes and wastewaters. Some of the mercury contamination has escaped to the local environment, particularly at the Y-12 Plant in Oak Ridge, Tennessee, where approximately 330 metric tons of mercury were discharged to the environment between 1953 and 1963 (TN & Associates, 1998). Effective removal of mercury contamination from water is a complex and difficult problem. In particular, mercury treatment of natural waters is difficult because of the low regulatory standards. For example, the Environmental Protection Agency has established a national ambient water quality standard of 12 parts-per-trillion (ppt), whereas the standard is 1.8 ppt in the Great Lakes Region. In addition, mercury in the environment is typically present in several different forms, but sorption processes are rarely effective with more than one or two of these forms. To meet the low regulatory discharge limits, an effective sorption process must be able to address all forms of mercury present in the water. One approach is to apply different sorbents in series depending on the mercury speciation and the regulatory discharge limits. ADA Technologies, Inc. has developed four new sorbents to address the variety of mercury species present in industrial discharges and natural waters. Three of these sorbents have been field tested on contaminated creek water at the Y-12 Plant. Two of these sorbents have been successfully demonstrated very high removal efficiencies for soluble mercury species, reducing mercury concentrations at the outlet of a pilot-scale system to less than 12 ppt for as long as six months. The other sorbent tested at the Y-12 Plant targeted colloidal mercury not removed by standard sorption or filtration processes. At the Y-12 Plant, colloidal mercury appears to be associated with iron, so a sorbent that removes mercury-iron complexes in the presence of a

  18. Instrument for Airborne Measurement of Carbonyl Sulfide, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Southwest Sciences proposes to develop small, low power instrumentation for the real-time direct measurement of carbonyl sulfide (OCS) in the atmosphere, especially...

  19. Desulfurizing Difluorination Reaction of Benzyl Sulfides Using IF5

    OpenAIRE

    Fukuhara, Tadahito; Hara, Shoji

    2009-01-01

    A desulfurizing difluorination reaction of benzyl sulfides having a functional group such as an ester, a ketone, a nitrile, or an amide was performed by a reaction with IF5. Consequently, gem-difluoro compounds could be obtained selectively.

  20. An Epidemiological Study of Mercury Sensitization

    Directory of Open Access Journals (Sweden)

    Kazuhiro Sato

    1997-01-01

    Full Text Available Mercury sensitization has been historically in question and may be related to recent increases of type I allergic diseases. To clarify the epidemiological factors of mercury sensitization, we investigated factors relating to mercury sensitization in 215 medical students. Their allergic symptoms, family histories and lifestyles were studied by questionnaire. Patch tests were performed with HgCI2 (0.05% aq. and NiS04 (5% aq.. Anti- Dermatophagoides and anti-Crypfomeria pollen IgE antibodies in sera were also measured. Urinary mercury concentrations were measured in 25 mercury sensitized and 44 non-sensitized subjects (controls. Hair mercury concentrations were also measured in 19 sensitized and 22 non-sensitized subjects. While the positive rate of nickel was 6.0% (13/215, that of mercury was high (13.0%; 28/215. The subjects' individual histories of allergic rhinitis, eczema, urticaria and allergic conjunctivitis were significantly associated with family histories of these conditions (P<0.01, P<0.005 and P<0.005, respectively, as reported in the literature. However, no allergen- specific antibody positivity or past history of allergic disease was associated with mercury sensitization. Mercury sensitized subjects had experienced eczema caused by cosmetics, shampoos, soaps and haircreams significantly more frequently (P<0.05. The history of mercurochrome usage was not associated with mercury sensitization. The number of teeth treated with metals in mercury sensitized subjects was significantly higher than that in the control group (6.8±4.3 vs 4.8±1; P<0.05. There were significant differences in urinary mercury concentrations (specific gravity adjusted levels between mercury sensitized subjects and non-sensitized subjects (2.0±0.9 and 1.3±0.6 (xg/L, respectively; P<0.001. There were also significant differences in hair mercury concentrations between mercury sensitized and non-sensitized subjects (2.0±0.9 and 1.2±0.5 μg/g, respectively; P<0

  1. Mercury Phase II Study - Mercury Behavior across the High-Level Waste Evaporator System

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Crawford, C. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jackson, D. G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Shah, H. B. [Savannah River Remediation, LLC., Aiken, SC (United States); Jain, V. [Savannah River Remediation, LLC., Aiken, SC (United States); Occhipinti, J. E. [Savannah River Remediation, LLC., Aiken, SC (United States); Wilmarth, W. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-06-17

    The Mercury Program team’s effort continues to develop more fundamental information concerning mercury behavior across the liquid waste facilities and unit operations. Previously, the team examined the mercury chemistry across salt processing, including the Actinide Removal Process/Modular Caustic Side Solvent Extraction Unit (ARP/MCU), and the Defense Waste Processing Facility (DWPF) flowsheets. This report documents the data and understanding of mercury across the high level waste 2H and 3H evaporator systems.

  2. Assessing Mercury and Methylmercury Bioavailability in Sediment Pore Water Using Mercury-Specific Hydrogels

    Science.gov (United States)

    2015-06-01

    FINAL REPORT Assessing Mercury and Methylmercury Bioavailability in Sediment Pore Water Using Mercury -Specific Hydrogels SERDP Project ER-1771...From - To) 2010-2015 4. TITLE AND SUBTITLE Assessing Mercury and Methylmercury Bioavailability in 5a. CONTRACT NUMBER W912HQ-10-C-0069 Sediment...Using Mercury -Specific DGTs 5b. GRANT NUMBER ER-1771 5c. PROGRAM ELEMENT NUMBER NA 6. AUTHOR(S) Magar, Victor S.*, Steenhaut, Nicholas

  3. Mercury concentrations at a historically mercury-contaminated site in KwaZulu-Natal, South Africa

    CSIR Research Space (South Africa)

    Williams, CR

    2011-02-01

    Full Text Available . Biogeochem., 43:237?257 Barrat GJ, Combrink J (2002) An Assessment of the degree of mercury (Hg) bio-transformation in two river systems following discharges from a mercury recovery plant. Water SA Special Edition: WISA Proceedings 2002 Benoit JM... in mercury and methylmercury biogeochemical cycling and bioaccumulation within shallow estuaries. PhD thesis, University of Maryland, College Park Kim E-H, Mason RP, Porter ET, Soulen HL (2006) The impact of resuspension on sediment mercury dynamics...

  4. Amended Silicated for Mercury Control

    Energy Technology Data Exchange (ETDEWEB)

    James Butz; Thomas Broderick; Craig Turchi

    2006-12-31

    Amended Silicates{trademark}, a powdered, noncarbon mercury-control sorbent, was tested at Duke Energy's Miami Fort Station, Unit 6 during the first quarter of 2006. Unit 6 is a 175-MW boiler with a cold-side electrostatic precipitator (ESP). The plant burns run-of-the-river eastern bituminous coal with typical ash contents ranging from 8-15% and sulfur contents from 1.6-2.6% on an as-received basis. The performance of the Amended Silicates sorbent was compared with that for powdered activated carbon (PAC). The trial began with a period of baseline monitoring during which no sorbent was injected. Sampling during this and subsequent periods indicated mercury capture by the native fly ash was less than 10%. After the baseline period, Amended Silicates sorbent was injected at several different ratios, followed by a 30-day trial at a fixed injection ratio of 5-6 lb/MMACF. After this period, PAC was injected to provide a comparison. Approximately 40% mercury control was achieved for both the Amended Silicates sorbent and PAC at injection ratios of 5-6 lbs/MMACF. Higher injection ratios did not achieve significantly increased removal. Similar removal efficiencies have been reported for PAC injection trials at other plants with cold-side ESPs, most notably for plants using medium to high sulfur coal. Sorbent injection did not detrimentally impact plant operations and testing confirmed that the use of Amended Silicates sorbent does not degrade fly ash quality (unlike PAC). The cost for mercury control using either PAC or Amended Silicates sorbent was estimated to be equivalent if fly ash sales are not a consideration. However, if the plant did sell fly ash, the effective cost for mercury control could more than double if those sales were no longer possible, due to lost by-product sales and additional cost for waste disposal. Accordingly, the use of Amended Silicates sorbent could reduce the overall cost of mercury control by 50% or more versus PAC for locations where

  5. Determination of Hydrogen Sulfide in Fermentation Broths Containing SO21

    Science.gov (United States)

    Acree, T. E.; Sonoff, Elisabeth P.; Splittstoesser, D. F.

    1971-01-01

    A procedure for the determination of hydrogen sulfide in fermentation broths containing up to 100 μg of SO2 per ml is described. The method involves the sparging of H2S from the broth into a cadmium hydroxide absorption solution, the formation of methylene blue from the absorbed sulfide, and the measuring of this color spectrophotometrically. The use of cadmium hydroxide instead of zinc acetate, the common absorbent, substantially reduced the interference of SO2 with the analysis. PMID:5111300

  6. INVESTIGATIONS ON BIOCHEMICAL PURIFICATION OF GROUND WATER FROM HYDROGEN SULFIDE

    Directory of Open Access Journals (Sweden)

    Yu. P. Sedlukho

    2015-01-01

    Full Text Available The paper considers problems and features of biochemical removal of hydrogen sulfide from ground water. The analysis of existing methods for purification of ground water from hydrogen sulfide has been given in the paper. The paper has established shortcomings of physical and chemical purification of ground water. While using aeration methods for removal of hydrogen sulfide formation of colloidal sulfur that gives muddiness and opalescence to water occurs due to partial chemical air oxidation. In addition to this violation of sulfide-carbonate equilibrium taking place in the process of aeration due to desorption of H2S and CO2, often leads to clogging of degasifier nozzles with formed CaCO3 that causes serious operational problems. Chemical methods require relatively large flow of complex reagent facilities, storage facilities and transportation costs.In terms of hydrogen sulfide ground water purification the greatest interest is given to the biochemical method. Factors deterring widespread application of the biochemical method is its insufficient previous investigation and necessity to execute special research in order to determine optimal process parameters while purifying groundwater of a particular water supply source. Biochemical methods for oxidation of sulfur compounds are based on natural biological processes that ensure natural sulfur cycle. S. Vinogradsky has established a two-stage mechanism for oxidation of hydrogen sulfide with sulfur bacteria (Beggiatoa. The first stage presupposes oxidation of hydrogen sulphide to elemental sulfur which is accumulating in the cytoplasm in the form of globules. During the second stage sulfur bacteria begin to oxidize intracellular sulfur to sulfuric acid due to shortage of hydrogen sulfide.The paper provides the results of technological tests of large-scale pilot plants for biochemical purification of groundwater from hydrogen sulfide in semi-industrial conditions. Dependences of water quality

  7. Alternating current electroluminescent properties of zinc sulfide powders

    OpenAIRE

    Salimian, Alireza

    2012-01-01

    In order to investigate the alternating current electroluminescent properties of zinc sulfide powders the following experiments were conducted: synthesis of zinc sulfide phosphors (comprised of zinc, sulfur and copper dopant); thermal shocking of phosphor materials (sudden cooling, using liquid nitrogen, of phosphor particles heated up to 500oC) and analysis of their alternating current electroluminescent properties as well as studies of particle crystal structures by synchrotron and conventi...

  8. Structural Properties of Zinc Sulfide Polymer Nanocomposite with Alginate

    OpenAIRE

    A.M. Mieshkov; T.O. Berestok; L.F. Sukhodub; А.S. Оpanasyuk

    2015-01-01

    The comparison of structural and substructural characteristics of pure zinc sulfide and biopolymer based on ZnS composite with alginate was held by scanning electron microscopy, diffraction and X-ray fluorescence spectrometry. Films and nanostructures of zinc sulfide were obtained by chemical bath deposition from an aqueous solution of zinc nitrate, sodium alginate and tiaourea at 90 °C and synthesis time of 30-120 min. It is established that growth occurs through the formation of condensate ...

  9. Percolation of cadmium across a mercury film

    International Nuclear Information System (INIS)

    Malek, K.; Gobal, F.

    2003-01-01

    Electrodeposition/dissolution of cadmium onto a film of mercury shows some deviations from the natural liquidity of mercury caused by the reduction of Cd onto it. Percolation and fractal analyzes were done on the surface and the bulk of the mercury film during diffusion of Cd species (atoms). These show that the fractal dimensions of the Cd-inserted mercury film are about 2.11 and 2.54 near the surface of the mercury film and at deeper points inside the film, respectively. The insertion process has a negligible effect on the surface morphology of the mercury film and there is a phase transition in the bulk, as well as a geometrical transition during the Cd-insertion (de-insertion) process. This corresponds to a percolation threshold of about 0.2 mol l -1 Cd content

  10. Mercury in dated Greenland marine sediments

    DEFF Research Database (Denmark)

    Asmund, G.; Nielsen, S.P.

    2000-01-01

    Twenty marine sediment cores from Greenland were analysed for mercury, and dated by the lead-210 method. In general the cores exhibit a mercury profile with higher mercury concentrations in the upper centimetres of the core. The cores were studied by linear regression of In Hg vs, age...... of the sediment for the youngest 100 years. As a rule the mercury decreased with depth in the sediment with various degrees of significance. The increase of the mercury flux during the last 100 years is roughly a doubling. The increase may be of anthropogenic origin as it is restricted to the last 100 years....... In four cores the concentration of manganese was found also to increase in the top layers indicating diagenesis. In the other cases the higher concentrations were not accompanied by higher manganese concentrations. The mercury flux to the sediment surface was generally proportional to the Pb-210 flux...

  11. Human accumulation of mercury in Greenland

    DEFF Research Database (Denmark)

    Johansen, P.; Mulvad, G.; Pedersen, H. S.

    2007-01-01

    In the Arctic, the traditional diet exposes its people to a high intake of mercury especially from marine mammals. To determine whether the mercury is accumulated in humans, we analyzed autopsy samples of liver, kidney and spleen from adult ethnic Greenlanders who died between 1990 and 1994 from...... a wide range of causes, natural and violent. Liver, kidney and spleen samples from between 33 and 71 case subjects were analyzed for total mercury and methylmercury, and liver samples also for selenium. Metal levels in men and women did not differ and were not related to age except in one case, i.......e. for total mercury in liver, where a significant declining concentration with age was observed. The highest total mercury levels were found in kidney followed by liver and spleen. Methylmercury followed the same pattern, but levels were much lower, constituting only 19% of the total mercury concentration...

  12. Acclimation of subsurface microbial communities to mercury

    DEFF Research Database (Denmark)

    de Lipthay, Julia R; Rasmussen, Lasse D; Øregaard, Gunnar

    2008-01-01

    We studied the acclimation to mercury of bacterial communities of different depths from contaminated and noncontaminated floodplain soils. The level of mercury tolerance of the bacterial communities from the contaminated site was higher than those of the reference site. Furthermore, the level...... of mercury tolerance and functional versatility of bacterial communities in contaminated soils initially were higher for surface soil, compared with the deeper soils. However, following new mercury exposure, no differences between bacterial communities were observed, which indicates a high adaptive potential...... of the subsurface communities, possibly due to differences in the availability of mercury. IncP-1 trfA genes were detected in extracted community DNA from all soil depths of the contaminated site, and this finding was correlated to the isolation of four different mercury-resistance plasmids, all belonging...

  13. Sulfide oxidation in fluidized bed bioreactor using nylon support material.

    Science.gov (United States)

    Midha, Varsha; Jha, M K; Dey, Apurba

    2012-01-01

    A continuous fluidized bed bioreactor (FBBR) with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25, 50 and 75 min and upflow velocity of 14, 17 and 20 m/hr. The effects of upflow velocity, hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model. Mixed culture obtained from the activated sludge, taken from tannery effluent treatment plant, was used as a source for microorganisms. The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m3, respectively. Experiments were carried out in the reactor at a temperature of (30 +/- 2) degrees C, at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles. Biofilm thickness reached (42 +/- 3) microm after 15 days from reactor start-up. The sulfide oxidation, sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities. The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times. Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate. The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.

  14. Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling.

    Science.gov (United States)

    Wang, Aijie; Liu, Chunshuang; Ren, Nanqi; Han, Hongjun; Lee, Duujong

    2010-06-15

    Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S(0)), N(2), and CO(2), or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.51000 mg/L influent sulfide, however, the DSR system will break down. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Laser cleaning of sulfide scale on compressor impeller blade

    International Nuclear Information System (INIS)

    Tang, Q.H.; Zhou, D.; Wang, Y.L.; Liu, G.F.

    2015-01-01

    Highlights: • The effects of sulfide layers and fluence values on the mechanism of laser cleaning were experimentally established. • The specimen surface with sulfide scale becomes slightly smoother than that before laser cleaning. • The mechanism of laser cleaning the sulfide scale of stainless steel is spallation without oxidization. • It would avoid chemical waste and dust pollution using a fiber laser instead of using nitric acids or sandblasting. - Abstract: Sulfide scale on the surface of a compressor impeller blade can considerably reduce the impeller performance and its service life. To prepare for subsequent remanufacturing, such as plasma spraying, it needs to be removed completely. In the corrosion process on an FV(520)B stainless steel, sulfide scale is divided into two layers because of different outward diffusion rates of Cr, Ni and Fe. In this paper, the cleaning threshold values of the upper and inner layers and the damage threshold value of the substrate were investigated using a pulsed fiber laser. To obtain experimental evidence, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and 3D surface profilometry were employed to investigate the two kinds of sulfide layers on specimens before, during, and after laser cleaning.

  16. Thiosulphate assisted phytoextraction of mercury contaminated soils at the Wanshan Mercury Mining District, Southwest China

    Directory of Open Access Journals (Sweden)

    J. Wang

    2013-10-01

    Full Text Available Wanshan, known as the “Mercury Capital” of China, is located in the Southwest of China. Due to the extensive mining and smelting works in the Wanshan area, the local ecosystem has been serious contaminated with mercury. In the present study, a number of soil samples were taken from the Wanshan mercury mining area and the mercury fractionations in soils were analyzed using sequential extraction procedure technique. The obtained results showed that the dominate mercury fractions (represent 95% of total mercury were residual and organic bound mercury. A field trial was conducted in a mercury polluted farmland at the Wanshan mercury mine. Four plant species Brassica juncea Czern. et Coss.var. ASKYC (ASKYC, Brassica juncea Czern. et Coss.var.DPDH (DPDH, Brassica juncea Czern. et Coss.var.CHBD(CHBD, Brassica juncea Czern. et Coss.var.LDZY (LDZY were tested their ability to extract mercury from soil with thiosulphate amendment. The results indicated that the mercury concentration in the roots and shoots of the four plants were significantly increased with thiosulphate treatment. The mercury phytoextraction yield of ASKYC, DPDH, CHBD and LDZY were 92, 526, 294 and 129 g/ha, respectively

  17. Blood Mercury Levels of Zebra Finches Are Heritable: Implications for the Evolution of Mercury Resistance.

    Directory of Open Access Journals (Sweden)

    Kenton A Buck

    Full Text Available Mercury is a ubiquitous metal contaminant that negatively impacts reproduction of wildlife and has many other sub-lethal effects. Songbirds are sensitive bioindicators of mercury toxicity and may suffer population declines as a result of mercury pollution. Current predictions of mercury accumulation and biomagnification often overlook possible genetic variation in mercury uptake and elimination within species and the potential for evolution in affected populations. We conducted a study of dietary mercury exposure in a model songbird species, maintaining a breeding population of zebra finches (Taeniopygia guttata on standardized diets ranging from 0.0-2.4 μg/g methylmercury. We applied a quantitative genetics approach to examine patterns of variation and heritability of mercury accumulation within dietary treatments using a method of mixed effects modeling known as the 'animal model'. Significant variation in blood mercury accumulation existed within each treatment for birds exposed at the same dietary level; moreover, this variation was highly repeatable for individuals. We observed substantial genetic variation in blood mercury accumulation for birds exposed at intermediate dietary concentrations. Taken together, this is evidence that genetic variation for factors affecting blood mercury accumulation could be acted on by selection. If similar heritability for mercury accumulation exists in wild populations, selection could result in genetic differentiation for populations in contaminated locations, with possible consequences for mercury biomagnification in food webs.

  18. Radioactive mercury distribution in biological fluids and excretion in human subjects after inhalation of mercury vapor

    International Nuclear Information System (INIS)

    Cherian, M.G.; Hursh, J.B.; Clarkson, T.W.; Allen, J.

    1978-01-01

    The distribution of mercury in red blood cells (RBCs) and plasma, and its excretion in urine and feces are described in five human subjects during the first 7 days following inhalation of radioactive mercury vapor. A major portion (98%) of radioactive mercury in whole blood is initially accumulated in the RBCs and is transferred partly to the plasma compartment until the ratio of mercury in RBCs to plasma is about 2 within 20 h. The cumulative urinary and fecal excretion of mercury for 7 days is about 11.6% of the retained dose, and is closely related to the percent decline in body burden of mercury. There is little correlation between either the urinary excretion and plasma radioactivity of mercury, or the specific activities of urine and plasma mercury, suggesting a mechanism other than a direct glomerular filtration involved in the urinary excretion of recently exposed mercury. These studies suggest that blood mercury levels can be used as an index of recent exposure, while urinary levels may be an index of renal concentration of mercury. However, there is no reliable index for mercury concentration in the brain

  19. Thiosulphate assisted phytoextraction of mercury contaminated soils at the Wanshan Mercury Mining District, Southwest China

    Directory of Open Access Journals (Sweden)

    J Wang

    2013-10-01

    Full Text Available Wanshan, known as the “Mercury Capital” of China, is located in the Southwest of China. Due to the extensive mining and smelting works in the Wanshan area, the local ecosystem has been serious contaminated with mercury. In the present study, a number of soil samples were taken from the Wanshan mercury mining area and the mercury fractionations in soils were analyzed using sequential extraction procedure technique. The obtained results showed that the dominate mercury fractions (represent 95% of total mercury were residual and organic bound mercury. A field trial was conducted in a mercury polluted farmland at the Wanshan mercury mine. Four plant species Brassica juncea Czern. et Coss.var. ASKYC (ASKYC, Brassica juncea Czern. et Coss.var.DPDH (DPDH, Brassica juncea Czern. et Coss.var.CHBD(CHBD, Brassica juncea Czern. et Coss.var.LDZY (LDZY were tested their ability to extract mercury from soil with thiosulphate amendment. The results indicated that the mercury concentration in the roots and shoots of the four plants were significantly increased with thiosulphate treatment. The mercury phytoextraction yield of ASKYC, DPDH, CHBD and LDZY were 92, 526, 294 and 129 g/ha, respectively.

  20. Orbital multispectral mapping of Mercury with the MESSENGER Mercury Dual Imaging System: Evidence for the origins of plains units and low-reflectance material

    Science.gov (United States)

    Murchie, Scott L.; Klima, Rachel L.; Denevi, Brett W.; Ernst, Carolyn M.; Keller, Mary R.; Domingue, Deborah L.; Blewett, David T.; Chabot, Nancy L.; Hash, Christopher D.; Malaret, Erick; Izenberg, Noam R.; Vilas, Faith; Nittler, Larry R.; Gillis-Davis, Jeffrey J.; Head, James W.; Solomon, Sean C.

    2015-07-01

    A principal data product from MESSENGER's primary orbital mission at Mercury is a global multispectral map in eight visible to near-infrared colors, at an average pixel scale of 1 km, acquired by the Mercury Dual Imaging System. The constituent images have been calibrated, photometrically corrected to a standard geometry, and map projected. Global analysis reveals no spectral units not seen during MESSENGER's Mercury flybys and supports previous conclusions that most spectral variation is related to changes in spectral slope and reflectance between spectral end-member high-reflectance red plains (HRP) and low-reflectance material (LRM). Comparison of color properties of plains units mapped on the basis of morphology shows that the two largest unambiguously volcanic smooth plains deposits (the interior plains of Caloris and the northern plains) are close to HRP end members and have average color properties distinct from those of most other smooth plains and intercrater plains. In contrast, smaller deposits of smooth plains are nearly indistinguishable from intercrater plains on the basis of their range of color properties, consistent with the interpretation that intercrater plains are older equivalents of smooth plains. LRM having nearly the same reflectance is exposed in crater and basin ejecta of all ages, suggesting impact excavation from depth of material that is intrinsically dark or darkens very rapidly, rather than gradual darkening of exposed material purely by space weathering. A global search reveals no definitive absorptions attributable to Fe2+-containing silicates or to sulfides over regions 20 km or more in horizontal extent, consistent with results from MESSENGER's Mercury Atmospheric and Surface Composition Spectrometer. The only absorption-like feature identified is broad upward curvature of the spectrum centered near 600 nm wavelength. The feature is strongest in freshly exposed LRM and weak or absent in older exposures of LRM. We modeled spectra

  1. STRESS SENSITIVITY OF MERCURY INJECTION MEASUREMENTS

    OpenAIRE

    Guise, P; Grattoni, C; Allshorn, S; Fisher, QJ; Schiffer, A

    2017-01-01

    Many petrophysical properties (e.g. permeability, electrical resistivity etc.) of tight rocks are very stress sensitive. However, most mercury injection measurements are made using an instrument that does not apply a confining pressure to the samples. Here we further explore the implications of the use and analysis of data from mercury injection porosimetry or mercury capillary pressure measurements (MICP). Two particular aspects will be discussed. First, the effective stress acting on sample...

  2. Mercury in polar bears from Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Lentfer, J.W.; Galster, W.A.

    1987-04-01

    Alaskan polar bear (Ursus maritimus) muscle and liver samples collected in 1972 were analyzed for total mercury. Bears north of Alaska had more mercury than bears west of Alaska. The only difference between young and adult animals was in the northern area where adults had more mercury in liver tissue than young animals. Levels were probably not high enough to be a serious threat to bears.

  3. Surface composition of Mercury from reflectance spectrophotometry

    Science.gov (United States)

    Vilas, Faith

    1988-01-01

    The controversies surrounding the existing spectra of Mercury are discussed together with the various implications for interpretations of Mercury's surface composition. Special attention is given to the basic procedure used for reducing reflectance spectrophotometry data, the factors that must be accounted for in the reduction of these data, and the methodology for defining the portion of the surface contributing the greatest amount of light to an individual spectrum. The application of these methodologies to Mercury's spectra is presented.

  4. The Messenger Mission to Mercury

    CERN Document Server

    Domingue, D. L

    2007-01-01

    NASA’s MESSENGER mission, launched on 3 August, 2004 is the seventh mission in the Discovery series. MESSENGER encounters the planet Mercury four times, culminating with an insertion into orbit on 18 March 2011. It carries a comprehensive package of geophysical, geological, geochemical, and space environment experiments to complete the complex investigations of this solar-system end member, which begun with Mariner 10. The articles in this book, written by the experts in each area of the MESSENGER mission, describe the mission, spacecraft, scientific objectives, and payload. The book is of interest to all potential users of the data returned by the MESSENGER mission, to those studying the nature of the planet Mercury, and by all those interested in the design and implementation of planetary exploration missions.

  5. Augustus as Mercury at last

    Directory of Open Access Journals (Sweden)

    Paulo Martins

    2017-07-01

    Full Text Available My purpose in this paper is to investigate and to analyse the representation of Augustus as Mercury, and what this association may suggest and mean to the Romans from both the urbs and the prouinciae, focusing the epigraphy, the numismatic, and the literature. Furthermore, I review three researches that someway work this problem: Bandinelli, Zanker and Martins. Even though the associations between divinities and rulers were very common – Augustus represented as Apollo, Jupiter or Neptune; Tiberius as Apollo; Claudius as Jupiter; or Commodus as Hercules –, the discussion on the relationship between Augustus and Mercury is very rare in recent bibliography. The latest relevant research on this subject dates back to the first half of the twentieth century. Chittenden’s work on numismatic and Grether’s article on epigraphy are both very important. Thus, new evidences must be considered, so that we can further investigate these representations in the Roman world.

  6. Mercury dosing solutions for fluorescent lamps

    Energy Technology Data Exchange (ETDEWEB)

    Corazza, A; Boffito, C [SAES Getters S.p.A., Viale Italia 77, Lainate (MI) 20020 (Italy)], E-mail: alessio_corazza@saes-group.com

    2008-07-21

    A review of the different technologies used to dose mercury in fluorescent lamps is presented. Conventional liquid mercury dosing is gradually being replaced with more reliable and environmentally friendly solutions that enable a significant reduction of the amount of mercury introduced in the lamp, so as to cope with more stringent regulations issued to minimize the environmental impact of exhausted lamps. This paper will review the most advanced novel methods to assure an accurate and fine dosing of mercury in fluorescent lamps, especially focusing on solutions based on the use of solid alloys.

  7. Sorbents for mercury removal from flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Granite, Evan J.; Hargis, Richard A.; Pennline, Henry W.

    1998-01-01

    A review of the various promoters and sorbents examined for the removal of mercury from flue gas is presented. Commercial sorbent processes are described along with the chemistry of the various sorbent-mercury interactions. Novel sorbents for removing mercury from flue gas are suggested. Since activated carbons are expensive, alternate sorbents and/or improved activated carbons are needed. Because of their lower cost, sorbent development work can focus on base metal oxides and halides. Additionally, the long-term sequestration of the mercury on the sorbent needs to be addressed. Contacting methods between the flue gas and the sorbent also merit investigation.

  8. Risk assessment of mercury contaminated sites

    International Nuclear Information System (INIS)

    Hempel, M.

    1993-01-01

    At two sites, highly contaminated with mercury, risk assessment was executed. Methods were developed to determine organomercury compounds in water, air and soil. Toxicity tests demonstrated the high toxicity of organomercury compounds compared to inorganic mercury. Besides highly toxic methylmercury, ethylmercury was found in soils close to a chemical plant in Marktredwitz. In ultrafiltration-experiments mercury showed great affinity to high molecular substances in water. Lysimeter-experiments proved, that organomercury compounds are adsorbed and transformed to inorganic and elemental mercury. (orig.) [de

  9. Alkaline sorbent injection for mercury control

    Science.gov (United States)

    Madden, Deborah A.; Holmes, Michael J.

    2002-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  10. Apparatus for isotopic alteration of mercury vapor

    Science.gov (United States)

    Grossman, Mark W.; George, William A.; Marcucci, Rudolph V.

    1988-01-01

    An apparatus for enriching the isotopic Hg content of mercury is provided. The apparatus includes a reactor, a low pressure electric discharge lamp containing a fill including mercury and an inert gas. A filter is arranged concentrically around the lamp. In a preferred embodiment, constant mercury pressure is maintained in the filter by means of a water-cooled tube that depends from it, the tube having a drop of mercury disposed in it. The reactor is arranged around the filter, whereby radiation from said lamp passes through the filter and into said reactor. The lamp, the filter and the reactor are formed of a material which is transparent to ultraviolet light.

  11. Identification of elemental mercury in the subsurface

    Science.gov (United States)

    Jackson, Dennis G

    2015-01-06

    An apparatus and process is provided for detecting elemental mercury in soil. A sacrificial electrode of aluminum is inserted below ground to a desired location using direct-push/cone-penetrometer based equipment. The insertion process removes any oxides or previously found mercury from the electrode surface. Any mercury present adjacent the electrode can be detected using a voltmeter which indicates the presence or absence of mercury. Upon repositioning the electrode within the soil, a fresh surface of the aluminum electrode is created allowing additional new measurements.

  12. Coal fired flue gas mercury emission controls

    International Nuclear Information System (INIS)

    Wu, Jiang; Pan, Weiguo; Cao, Yan; Pan, Weiping

    2015-01-01

    Mercury (Hg) is one of the most toxic heavy metals, harmful to both the environment and human health. Hg is released into the atmosphere from natural and anthropogenic sources and its emission control has caused much concern. This book introduces readers to Hg pollution from natural and anthropogenic sources and systematically describes coal-fired flue gas mercury emission control in industry, especially from coal-fired power stations. Mercury emission control theory and experimental research are demonstrated, including how elemental mercury is oxidized into oxidized mercury and the effect of flue gas contents on the mercury speciation transformation process. Mercury emission control methods, such as existing APCDs (air pollution control devices) at power stations, sorbent injection, additives in coal combustion and photo-catalytic methods are introduced in detail. Lab-scale, pilot-scale and full-scale experimental studies of sorbent injection conducted by the authors are presented systematically, helping researchers and engineers to understand how this approach reduces the mercury emissions in flue gas and to apply the methods in mercury emission control at coal-fired power stations.

  13. Ocular disorders among workers exposed to mercury.

    Science.gov (United States)

    Gabal, M S; Raslan, O A

    1995-01-01

    Mercury vapor exposed workers may show ocular changes, as well as other systems affection. A sample of 84 workers in preparing mercury fulminate were examined for conjunctival corneal and lenticular manifestation of long duration exposure, together with mercury urinary output. Lens changes were found in 50% of the involved workers while keratopathy as recorded in 34.5% of them. No statistically significant association was found between the occurrence of eye lesions and levels of urinary elimination of mercury. These results suggest local absorption of this element is most probably the underlying cause of ocular affection.

  14. Increased mercury emissions from modern dental amalgams.

    Science.gov (United States)

    Bengtsson, Ulf G; Hylander, Lars D

    2017-04-01

    All types of dental amalgams contain mercury, which partly is emitted as mercury vapor. All types of dental amalgams corrode after being placed in the oral cavity. Modern high copper amalgams exhibit two new traits of increased instability. Firstly, when subjected to wear/polishing, droplets rich in mercury are formed on the surface, showing that mercury is not being strongly bonded to the base or alloy metals. Secondly, high copper amalgams emit substantially larger amounts of mercury vapor than the low copper amalgams used before the 1970s. High copper amalgams has been developed with focus on mechanical strength and corrosion resistance, but has been sub-optimized in other aspects, resulting in increased instability and higher emission of mercury vapor. This has not been presented to policy makers and scientists. Both low and high copper amalgams undergo a transformation process for several years after placement, resulting in a substantial reduction in mercury content, but there exist no limit for maximum allowed emission of mercury from dental amalgams. These modern high copper amalgams are nowadays totally dominating the European, US and other markets, resulting in significant emissions of mercury, not considered when judging their suitability for dental restoration.

  15. Side effects of mercury in dental amalgam

    Directory of Open Access Journals (Sweden)

    Titiek Berniyanti

    2008-03-01

    Full Text Available Dental amalgam is an alloy composed of mixture of approximately equal parts of elemental liquid mercury and an alloy powder. The popularity of amalgam arises from excellent long term performance, ease of use and low cost. Despite the popularity of dental amalgam as restorative material, there have been concerns regarding the potential adverse health and environmental effects arising from exposure to mercury in amalgam. They have long been believed to be of little significance as contributors to the overall body burden of mercury, because the elemental form of mercury is rapidly consumed in the setting reaction of the restoration. In 1997, 80% of dentist in Indonesia still using amalgam as an alternative material, and 60% of them treat the rest of unused amalgam carelessly. In recent years, the possible environmental and health impact caused by certain routines in dental practice has attracted attention among regulators. As part of point source reduction strategies, the discharge of mercury/amalgam-contaminated wastes has been regulated in a number of countries, even though it has been documented that by adopting appropriate mercury hygiene measures, the impact of amalgam use in dentistry is minimal. The purpose of this paper is to examine on studies that relate mercury levels in human to the presence of dental amalgams. It is concluded that even though mercury used in filling is hazardous, if normal occupational recommendations for proper mercury hygiene routines and source of reduction strategies are followed, no occupational health risk can be assumed.

  16. Observations of Mercury in 1988 and 1989

    International Nuclear Information System (INIS)

    Schmude, R.W. Jr.

    1990-01-01

    A visual study of the planet Mercury was carried out in May 1988 and in April and May 1989. Most of the observations were made with the 35.5-cm telescope at the Texas A ampersand M University Observatory. This report presents drawings and a map of Mercury that covers the longitude range of 195-285 deg. One important finding was that a polarizing filter combined with color filters gives a sharper view of the planet. It is also concluded that high-resolution images of Mercury's terminator, either as seen from the earth or with the Hubble Space Telescope, can provide information about Mercury's topography. 10 refs

  17. Phytoremediation of Ionic and Methyl Mercury Pollution

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, Richard B.

    2005-06-01

    Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems. Our current strategy is to engineer plants to

  18. EDITORIAL: Mercury-free discharges for lighting

    Science.gov (United States)

    Haverlag, M.

    2007-07-01

    This special Cluster of articles in Journal of Physics D: Applied Physics covers the subject of mercury-free discharges that are being investigated by different light source researchers, as an alternative to existing mercury-containing lamps. The main driving force to move away from mercury-containing discharge light sources is connected to the environmentally unfriendly nature of mercury. After inhalation or direct contact, severe mercury exposure can lead to damage to human brain cells, the kidneys, the liver and the nervous system. For this reason, the use of mercury in products is becoming more and more restricted by different governmental bodies. In the lighting industry, however, many products still make use of mercury, for different reasons. The main reason is that mercury-containing products are, in most cases, more efficient than mercury-free products. For a realistic comparison of the environmental impact, the mercury-contamination due to electricity production must be taken into account, which depends on the type of fuel being used. For an average European fuel-mix, the amount of mercury that is released into the environment is around 29 μg kWh-1. This means that a typical 30 W TL lamp during a lifetime of 20,000 hours will release a total of about 20 mg mercury due to electricity production, which exceeds the total mercury dose in the lamp (more and more of which is being recycled) by a factor of 5-10 for a modern TL lamp. This illustrates that, quite apart from other environmental arguments like increased CO2 production, mercury-free alternatives that use more energy can in fact be detrimental for the total mercury pollution over the lifetime of the lamp. For this reason, the lighting industry has concentrated on lowering the mercury content in lamps as long as no efficient alternatives exist. Nevertheless, new initiatives for HID lamps and fluorescent lamps with more or less equal efficiency are underway, and a number of them are described in this

  19. Bio-orthogonal "click-and-release" donation of caged carbonyl sulfide (COS) and hydrogen sulfide (H2S).

    Science.gov (United States)

    Steiger, Andrea K; Yang, Yang; Royzen, Maksim; Pluth, Michael D

    2017-01-24

    Hydrogen sulfide (H 2 S) is an important biomolecule with high therapeutic potential. Here we leverage the inverse-electron demand Diels-Alder (IEDDA) click reaction between a thiocarbamate-functionalized trans-cyclooctene and a tetrazine to deliver carbonyl sulfide (COS), which is quickly converted to H 2 S by the uniquitous enzyme carbonic anhydrase (CA), thus providing a new strategy for bio-orthogonal COS/H 2 S donation.

  20. Rapid Monitoring of Mercury in Air from an Organic Chemical Factory in China Using a Portable Mercury Analyzer

    OpenAIRE

    Yasutake, Akira; Cheng, Jin Ping; Kiyono, Masako; Uraguchi, Shimpei; Liu, Xiaojie; Miura, Kyoko; Yasuda, Yoshiaki; Mashyanov, Nikolay

    2011-01-01

    A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated mercury concentrations in ambient air and vegetation. Mercury concentrations of up to 600 ng/m3 in air o...

  1. Multiscale geomorphometric modeling of Mercury

    Science.gov (United States)

    Florinsky, I. V.

    2018-02-01

    Topography is one of the key characteristics of a planetary body. Geomorphometry deals with quantitative modeling and analysis of the topographic surface and relationships between topography and other natural components of landscapes. The surface of Mercury is systematically studied by interpretation of images acquired during the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. However, the Mercurian surface is still little explored by methods of geomorphometry. In this paper, we evaluate the Mercury MESSENGER Global DEM MSGR_DEM_USG_SC_I_V02 - a global digital elevation model (DEM) of Mercury with the resolution of 0.015625° - as a source for geomorphometric modeling of this planet. The study was performed at three spatial scales: the global, regional (the Caloris basin), and local (the Pantheon Fossae area) ones. As the initial data, we used three DEMs of these areas with resolutions of 0.25°, 0.0625°, and 0.015625°, correspondingly. The DEMs were extracted from the MESSENGER Global DEM. From the DEMs, we derived digital models of several fundamental morphometric variables, such as: slope gradient, horizontal curvature, vertical curvature, minimal curvature, maximal curvature, catchment area, and dispersive area. The morphometric maps obtained represent peculiarities of the Mercurian topography in different ways, according to the physical and mathematical sense of a particular variable. Geomorphometric models are a rich source of information on the Mercurian surface. These data can be utilized to study evolution and internal structure of the planet, for example, to visualize and quantify regional topographic differences as well as to refine geological boundaries.

  2. Assessing the Behavior of Typically Lithophile Elements Under Highly Reducing Conditions Relevant to the Planet Mercury

    Science.gov (United States)

    Rowland, Rick, II; Vander Kaaden, Kathleen E.; McCubbin, Francis M.; Danielson, Lisa R.

    2017-01-01

    With the data returned from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, there are now numerous constraints on the physical and chemical properties of Mercury, including its surface composition. The high Sand low FeO contents observed from MESSENGER suggest a low oxygen fugacity of the present materials on the planet's surface. Most of our understanding of elemental partitioning behavior comes from observations made on terrestrial rocks, but Mercury's oxygen fugacity is far outside the conditions of those samples, estimated at approximately 3-7 log units below the Iron-Wtistite (lW) oxygen buffer, several orders of magnitude more reducing than other terrestrial bodies we have data from. With limited oxygen available, lithophile elements may instead exhibit chalcophile, halophile, or siderophile behaviors. Furthermore, very few natural samples of rocks that formed under reducing conditions (e.g., enstatite chondrites, achondrites, aubrites) are available in our collections for examination of this change in geochemical affinity. Our goal is to determine the elemental partitioning behavior of typically lithophile elements at lower oxygen fugacity as a function of temperature and pressure. Experiments were conducted at I GPa in a 13 mm QUICKpress piston cylinder and at 4 GPa in an 880-ton multianvil press, at temperatures up to 1850degC. The composition of starting materials for the experiments were designed so the final run products contained metal, silicate melt, and sulfide melt phases. Oxygen fugacity was controlled in the experiments by adding silicon metal to the samples, in order to utilize the Si-Si02 buffer, which is approximately 5 log units more reducing than the IW buffer at our temperatures of interest. The target silicate melt composition was diopside (CaMgSi206) because measured surface compositions indicate partial melting of a pyroxene-rich mantle. The results of our experiments will aid in our understanding of

  3. Subnanometer Thin β-Indium Sulfide Nanosheets.

    Science.gov (United States)

    Acharya, Shinjita; Sarkar, Suresh; Pradhan, Narayan

    2012-12-20

    Nanosheets are a peculiar kind of nanomaterials that are grown two-dimensionally over a micrometer in length and a few nanometers in thickness. Wide varieties of inorganic semiconductor nanosheets are already reported, but controlling the crystal growth and tuning their thickness within few atomic layers have not been yet explored. We investigate here the parameters that determine the thickness and the formation mechanism of subnanometer thin (two atomic layers) cubic indium sulfide (In2S3) nanosheets. Using appropriate reaction condition, the growth kinetics is monitored by controlling the decomposition rate of the single source precursor of In2S3 as a function of nucleation temperature. The variation in the thickness of the nanosheets along the polar [111] direction has been correlated with the rate of evolved H2S gas, which in turn depends on the rate of the precursor decomposition. In addition, it has been observed that the thickness of the In2S3 nanosheets is related to the nucleation temperature.

  4. Positive trends in Southern Hemisphere carbonyl sulfide

    Science.gov (United States)

    Kremser, Stefanie; Jones, Nicholas B.; Palm, Mathias; Lejeune, Bernard; Wang, Yuting; Smale, Dan; Deutscher, Nicholas M.

    2015-11-01

    Transport of carbonyl sulfide (OCS) from the troposphere to the stratosphere contributes sulfur to the stratospheric aerosol layer, which reflects incoming short-wave solar radiation, cooling the climate system. Previous analyses of OCS observations have shown no significant trend, suggesting that OCS is unlikely to be a major contributor to the reported increases in stratospheric aerosol loading and indicating a balanced OCS budget. Here we present analyses of ground-based Fourier transform spectrometer measurements of OCS at three Southern Hemisphere sites spanning 34.45°S to 77.80°S. At all three sites statistically significant positive trends are seen from 2001 to 2014 with an observed overall trend in total column OCS at Wollongong of 0.73 ± 0.03%/yr, at Lauder of 0.43 ± 0.02%/yr, and at Arrival Heights of 0.45 ± 0.05%/yr. These observed trends in OCS imply that the OCS budget is not balanced and could contribute to constraints on current estimates of sources and sinks.

  5. Thiosulfate leaching of gold from sulfide wastes

    Energy Technology Data Exchange (ETDEWEB)

    Block-Bolten, A.; Torma, A.E.

    1986-07-01

    The kinetics of gold extraction from lead-zinc sulfide flotation tailings by thiosulfate leachants has been investigated. The order of reaction as well as the overall reaction rate constant were, with respect to thiosulfate concentration, calculated to be n=0.75 and k=1.05 x 10/sup -6/ mol/sup 1/4/ dm/sup 5/4/ min/sup -1/. The apparent activation energy was found to be ..delta..E/sub a/=48.53 kJ and the frequency factor A=7.5 x 10/sup 2/ mol dm/sup -3/ min/sup -1/. This activation energy value suggests chemical control of the reaction mechanism. Optimum leach temperature of 50/sup 0/C was established. Gold extractions as high as 99% have been realized in two step countercurrent leachings. Change in pH throughout the leaching process was found to be an excellent indicator for the progress of the extraction. A preliminary economic evaluation of the process is given.

  6. Fluorescence sensing system for seafloor massive sulfides

    Science.gov (United States)

    Yamazaki, T.; Okanishi, D.; Nagano, H.; Nakatani, N.; Arai, R.

    2010-12-01

    Seafloor Massive Sulfides (SMS) including Au, Ag, Cu, Zn, Pb and some rare earth elements exist in exclusive economic zones (EEZ) of Pacific island countries and the ones in Japan’s EEZ are the largest and very much attractive. However, there are many problems to be solved for the development. The most important point is the location of ore dressing. If SMS were dressed in the water, energy and cost of transport would drastically decrease. Therefore, fundamental ore dressing method which is an optical measurement, fluorescence sensing system in water is studied. It seems to be able to apply to exploration and mining. No sun light means that ideal optical measurements are possible under artificial one in deep water. However, quite less studies have been done for the optical measurements because general sensing methods at deep water are sound and supersonic waves. Using a light system, the light attenuation and fluorescence characteristics in water are studied. From this study, it is revealed that fluorescence sensing system is applicable and useful for the development of SMS.

  7. The role of hydrogen sulfide in stroke

    Directory of Open Access Journals (Sweden)

    Yang Dou

    2016-01-01

    Full Text Available Stroke is a kind of acute cerebrovascular disease characterized by the focal lack of neurological function, including ischemic stroke and hemorrhagic stroke. As society ages rapidly, stroke has become the second leading cause of disability and death, and also become the main threat to human health and life. In recent years, findings from increasing animal and clinical trials have supplied scientific evidences for the treatment of stroke. Hydrogen sulfide (H 2 S, which has always been seen as a toxic gas, now has been thought to be the third gaseous signaling molecule following nitric oxide and carbon monoxide. Accumulating evidences indicate that H 2 S plays an important role in stroke. Given that its neuroprotective effect is dose-dependent, only when its concentration is relatively low, H 2 S can yield the neuroprotection, while high dose may lead to neurotoxicity. All these study results suggest that H 2 S may offer a new promising application for the therapy of stroke. Here, our review will present the role of H 2 S in stroke from its mechanism to animal and clinical studies.

  8. Hydrogen Sulfide and Endothelium-Dependent Vasorelaxation

    Directory of Open Access Journals (Sweden)

    Jerzy Bełtowski

    2014-12-01

    Full Text Available In addition to nitric oxide and carbon monoxide, hydrogen sulfide (H2S, synthesized enzymatically from l-cysteine or l-homocysteine, is the third gasotransmitter in mammals. Endogenous H2S is involved in the regulation of many physiological processes, including vascular tone. Although initially it was suggested that in the vascular wall H2S is synthesized only by smooth muscle cells and relaxes them by activating ATP-sensitive potassium channels, more recent studies indicate that H2S is synthesized in endothelial cells as well. Endothelial H2S production is stimulated by many factors, including acetylcholine, shear stress, adipose tissue hormone leptin, estrogens and plant flavonoids. In some vascular preparations H2S plays a role of endothelium-derived hyperpolarizing factor by activating small and intermediate-conductance calcium-activated potassium channels. Endothelial H2S signaling is up-regulated in some pathologies, such as obesity and cerebral ischemia-reperfusion. In addition, H2S activates endothelial NO synthase and inhibits cGMP degradation by phosphodiesterase 5 thus potentiating the effect of NO-cGMP pathway. Moreover, H2S-derived polysulfides directly activate protein kinase G. Finally, H2S interacts with NO to form nitroxyl (HNO—a potent vasorelaxant. H2S appears to play an important and multidimensional role in endothelium-dependent vasorelaxation.

  9. Luminescent sulfides of monovalent and trivalent cations

    International Nuclear Information System (INIS)

    1975-01-01

    The invention discloses a family of luminescent materials or phosphors having a rhombohedral crystal structure and consisting essentially of a mixed host sulfide of at least one monovalent host cation and at least one trivalent host cation, and containing, for each mole of phosphor, 0.0005 to 0.05 mole of at least one activating cation. The monovalent host cations may be Na, K or Rb and Cs. The trivalent host cations may be Gd, La, Lu, Sc and Y. The activating cations may be one or more of trivalent As, Bi, Ce, Dy, Er, Pr, Sb, Sm, Tb and Tm; divalent Lu, Mn, Pb and Sn; and monovalent Ag, Cu and Tl. The novel phosphors may be used in devices to convert electron-beam, ultraviolet or x-ray energy to light in the visible spectrum. Such energy conversion can be employed for example in fluoroscopic screens, and in viewing screens of cathode-ray tubes and other electron tubes

  10. Comparison of Carbon XANES Spectra from an Iron Sulfide from Comet Wild 2 with an Iron Sulfide Interplanetary Dust Particle

    Science.gov (United States)

    Wirick, S.; Flynn, G. J.; Keller, L. P.; Sanford, S. A.; Zolensky, M. E.; Messenger, Nakamura K.; Jacobsen, C.

    2008-01-01

    Among one of the first particles removed from the aerogel collector from the Stardust sample return mission was an approx. 5 micron sized iron sulfide. The majority of the spectra from 5 different sections of this particle suggests the presence of aliphatic compounds. Due to the heat of capture in the aerogel we initially assumed these aliphatic compounds were not cometary but after comparing these results to a heated iron sulfide interplanetary dust particle (IDP) we believe our initial interpretation of these spectra was not correct. It has been suggested that ice coating on iron sulfides leads to aqueous alteration in IDP clusters which can then lead to the formation of complex organic compounds from unprocessed organics in the IDPs similar to unprocessed organics found in comets [1]. Iron sulfides have been demonstrated to not only transform halogenated aliphatic hydrocarbons but also enhance the bonding of rubber to steel [2,3]. Bromfield and Coville (1997) demonstrated using Xray photoelectron spectroscopy that "the surface enhancement of segregated sulfur to the surface of sulfided precipitated iron catalysts facilitates the formation of a low-dimensional structure of extraordinary properties" [4]. It may be that the iron sulfide acts in some way to protect aliphatic compounds from alteration due to heat.

  11. Atmospheric measurements of carbonyl sulfide, dimethyl sulfide, and carbon disulfide using the electron capture sulfur detector

    Science.gov (United States)

    Johnson, James E.; Bates, Timothy S.

    1993-01-01

    Measurements of atmospheric dimethyl sulfide (DMS), carbonyl sulfide (COS), and carbon disulfide (CS2) were conducted over the Atlantic Ocean on board the NASA Electra aircraft during the Chemical Instrumentation Test and Evaluation (CITE 3) project using the electron capture sulfur detector (ECD-S). The system employed cryogenic preconcentration of air samples, gas chromatographic separation, catalytic fluorination, and electron capture detection. Samples collected for DMS analysis were scrubbed of oxidants with NaOH impregnated glass fiber filters to preconcentration. The detection limits (DL) of the system for COS, DMS, and CS2 were 5, 5, and 2 ppt, respectively. COS concentrations ranged from 404 to 603 ppt with a mean of 489 ppt for measurements over the North Atlantic Ocean (31 deg N to 41 deg N), and from 395 to 437 ppt with a mean of 419 ppt for measurements over the Tropical Atlantic Ocean (11 deg S to 2 deg N). DMS concentrations in the lower marine boundary layer, below 600-m altitude, ranged from below DL to 150 ppt from flights over the North Atlantic, and from 9 to 104 ppt over the Tropical Atlantic. CS2 concentrations ranged from below DL to 29 ppt over the North Atlantic. Almost all CS2 measurements over the Tropical Atlantic were below DL.

  12. Silver sulfide nanoparticle assembly obtained by reacting an assembled silver nanoparticle template with hydrogen sulfide gas.

    Science.gov (United States)

    Chen, Rui; Nuhfer, Noel T; Moussa, Laura; Morris, Hannah R; Whitmore, Paul M

    2008-11-12

    A fast, simple procedure is described for obtaining an assembly of silver sulfide nanoparticles (Ag(2)S NPs) on a glass substrate through reaction of a template of an assembled layer of silver nanoparticles (Ag NPs) with hydrogen sulfide (H(2)S) gas. The Ag NP template was prepared by assembling a monolayer of spherical Ag NPs (mean diameter of 7.4 nm) on a polyethylenimine-treated glass substrate. Exposure to pure H(2)S for 10 min converted the Ag NPs of the template to Ag(2)S NPs. The resulting Ag(2)S NP assembly, which retains the template nanostructure and particle distribution, was characterized by optical absorption spectroscopy, atomic force microscopy, transmission electron microscopy (TEM), scanning high resolution TEM, energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The Ag(2)S NPs have a crystal structure of monoclinic acanthite, and while they retained the spherical shape of the original Ag NPs, their mean particle size increased to 8.4 nm due to changes to the crystal structure when the Ag NPs are converted into Ag(2)S NPs. The measured optical absorption edge of the Ag(2)S NP assembly indicated an indirect interband transition with a band gap energy of 1.71 eV. The Ag(2)S NP assembly absorbed light with wavelengths below 725 nm, and the absorbance increased monotonically toward the UV region.

  13. Hydrogen sulfide can inhibit and enhance oxygenic photosynthesis in a cyanobacterium from sulfidic springs.

    Science.gov (United States)

    Klatt, Judith M; Haas, Sebastian; Yilmaz, Pelin; de Beer, Dirk; Polerecky, Lubos

    2015-09-01

    We used microsensors to investigate the combinatory effect of hydrogen sulfide (H2 S) and light on oxygenic photosynthesis in biofilms formed by a cyanobacterium from sulfidic springs. We found that photosynthesis was both positively and negatively affected by H2 S: (i) H2 S accelerated the recovery of photosynthesis after prolonged exposure to darkness and anoxia. We suggest that this is possibly due to regulatory effects of H2 S on photosystem I components and/or on the Calvin cycle. (ii) H2 S concentrations of up to 210 μM temporarily enhanced the photosynthetic rates at low irradiance. Modelling showed that this enhancement is plausibly based on changes in the light-harvesting efficiency. (iii) Above a certain light-dependent concentration threshold H2 S also acted as an inhibitor. Intriguingly, this inhibition was not instant but occurred only after a specific time interval that decreased with increasing light intensity. That photosynthesis is most sensitive to inhibition at high light intensities suggests that H2 S inactivates an intermediate of the oxygen evolving complex that accumulates with increasing light intensity. We discuss the implications of these three effects of H2 S in the context of cyanobacterial photosynthesis under conditions with diurnally fluctuating light and H2 S concentrations, such as those occurring in microbial mats and biofilms. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  14. Chemical and colloidal aspects of collectorless flotation behavior of sulfide and non-sulfide minerals.

    Science.gov (United States)

    Aghazadeh, Sajjad; Mousavinezhad, Seyed Kamal; Gharabaghi, Mahdi

    2015-11-01

    Flotation has been widely used for separation of valuable minerals from gangues based on their surface characterizations and differences in hydrophobicity on mineral surfaces. As hydrophobicity of minerals widely differs from each other, their separation by flotation will become easier. Collectors are chemical materials which are supposed to make selectively valuable minerals hydrophobic. In addition, there are some minerals which based on their surface and structural features are intrinsically hydrophobic. However, their hydrophobicities are not strong enough to be floatable in the flotation cell without collectors such as sulfide minerals, coal, stibnite, and so forth. To float these minerals in a flotation cell, their hydrophobicity should be increased in specific conditions. Various parameters including pH, Eh, size distribution, mill types, mineral types, ore characterization, and type of reaction in flotation cells affect the hydrophobicity of minerals. Surface analysis results show that when sulfide minerals experience specific flotation conditions, the reactions on the surface of these minerals increase the amount of sulfur on the surface. These phenomenons improve the hydrophobicity of these minerals due to strong hydrophobic feature of sulfurs. Collectorless flotation reduces chemical material consumption amount, increases flotation selectivity (grade increases), and affects the equipment quantities; however, it can also have negative effects. Some minerals with poor surface floatability can be increased by adding some ions to the flotation system. Depressing undesirable minerals in flotation is another application of collectorless flotation.

  15. Maternal transfer of mercury to songbird eggs.

    Science.gov (United States)

    Ackerman, Joshua T; Hartman, C Alex; Herzog, Mark P

    2017-11-01

    We evaluated the maternal transfer of mercury to eggs in songbirds, determined whether this relationship differed between songbird species, and developed equations for predicting mercury concentrations in eggs from maternal blood. We sampled blood and feathers from 44 house wren (Troglodytes aedon) and 34 tree swallow (Tachycineta bicolor) mothers and collected their full clutches (n = 476 eggs) within 3 days of clutch completion. Additionally, we sampled blood and feathers from 53 tree swallow mothers and randomly collected one egg from their clutches (n = 53 eggs) during mid to late incubation (6-10 days incubated) to evaluate whether the relationship varied with the timing of sampling the mother's blood. Mercury concentrations in eggs were positively correlated with mercury concentrations in maternal blood sampled at (1) the time of clutch completion for both house wrens (R 2  = 0.97) and tree swallows (R 2  = 0.97) and (2) during mid to late incubation for tree swallows (R 2  = 0.71). The relationship between mercury concentrations in eggs and maternal blood did not differ with the stage of incubation when maternal blood was sampled. Importantly, the proportion of mercury transferred from mothers to their eggs decreased substantially with increasing blood mercury concentrations in tree swallows, but increased slightly with increasing blood mercury concentrations in house wrens. Additionally, the proportion of mercury transferred to eggs at the same maternal blood mercury concentration differed between species. Specifically, tree swallow mothers transferred 17%-107% more mercury to their eggs than house wren mothers over the observed mercury concentrations in maternal blood (0.15-1.92 μg/g ww). In contrast, mercury concentrations in eggs were not correlated with those in maternal feathers and, likewise, mercury concentrations in maternal blood were not correlated with those in feathers (all R 2  mercury concentrations from maternal blood to eggs

  16. Recovery of Mercury From Contaminated Liquid Wastes

    International Nuclear Information System (INIS)

    1998-01-01

    The Base Contract program emphasized the manufacture and testing of superior sorbents for mercury removal, testing of the sorption process at a DOE site, and determination of the regeneration conditions in the laboratory. During this project, ADA Technologies, Inc. demonstrated the following key elements of a successful regenerable mercury sorption process: (1) sorbents that have a high capacity for dissolved, ionic mercury; (2) removal of ionic mercury at greater than 99% efficiency; and (3) thermal regeneration of the spent sorbent. ADA's process is based on the highly efficient and selective sorption of mercury by noble metals. Contaminated liquid flows through two packed columns that contain microporous sorbent particles on which a noble metal has been finely dispersed. A third column is held in reserve. When the sorbent is loaded with mercury to the point of breakthrough at the outlet of the second column, the first column is taken off-line and the flow of contaminated liquid is switched to the second and third columns. The spent column is regenerated by heating. A small flow of purge gas carries the desorbed mercury to a capture unit where the liquid mercury is recovered. Laboratory-scale tests with mercuric chloride solutions demonstrated the sorbents' ability to remove mercury from contaminated wastewater. Isotherms on surrogate wastes from DOE's Y-12 Plant in Oak Ridge, Tennessee showed greater than 99.9% mercury removal. Laboratory- and pilot-scale tests on actual Y-12 Plant wastes were also successful. Mercury concentrations were reduced to less than 1 ppt from a starting concentration of 1,000 ppt. The treatment objective was 50 ppt. The sorption unit showed 10 ppt discharge after six months. Laboratory-scale tests demonstrated the feasibility of sorbent regeneration. Results show that sorption behavior is not affected after four cycles

  17. Worldwide trend of atmospheric mercury since 1995

    Directory of Open Access Journals (Sweden)

    F. Slemr

    2011-05-01

    Full Text Available Concern about the adverse effects of mercury on human health and ecosystems has led to tightening emission controls since the mid 1980s. But the resulting mercury emissions reductions in many parts of the world are believed to be offset or even surpassed by the increasing emissions in rapidly industrializing countries. Consequently, concentrations of atmospheric mercury are expected to remain roughly constant. Here we show that the worldwide atmospheric mercury concentrations have decreased by about 20 to 38 % since 1996 as indicated by long-term monitoring at stations in the Southern and Northern Hemispheres combined with intermittent measurements of latitudinal distribution over the Atlantic Ocean. The total reduction of the atmospheric mercury burden of this magnitude within 14 years is unusually large among most atmospheric trace gases and is at odds with the current mercury emission inventories with nearly constant anthropogenic emissions over this period. This suggests a major shift in the biogeochemical cycle of mercury including oceans and soil reservoirs. Decreasing reemissions from the legacy of historical mercury emissions are the most likely explanation for this decline since the hypothesis of an accelerated oxidation rate of elemental mercury in the atmosphere is not supported by the observed trends of other trace gases. Acidification of oceans, climate change, excess nutrient input and pollution may also contribute by their impact on the biogeochemistry of ocean and soils. Consequently, models of the atmospheric mercury cycle have to include soil and ocean mercury pools and their dynamics to be able to make projections of future trends.

  18. Mercury rising : mercury emissions from Ontario Power Generation's coal-fired plants

    International Nuclear Information System (INIS)

    Rang, S.

    2004-09-01

    Ontario Power Generation (OPG) operates 5 coal-fired power plants which are the largest single source of mercury emissions in Ontario. Mercury is a persistent, bioaccumulative neurotoxin which is considered toxic under the Canadian Environmental Protection Act. This report examines the health and environmental impacts of mercury, and the trends for mercury emission in Ontario. In 2002, the 5 coal-fired plants emitted 527 kg of mercury into the atmosphere and contributed 39 per cent of the total amount of mercury emitted into the air. While many other sectors have reduced their mercury emissions since 1988, Ontario's coal-fired plants have lagged behind and have actually increased mercury emissions by 16 per cent since 1988. This paper suggests that phasing out OPG coal-fired plants by 2007 could lead to a 39 per cent reduction in airborne mercury emissions. It would also allow Ontario to achieve the Canada Wide Standard for mercury emissions 3 years early, and would help both Ontario and Canada meet air pollution reduction commitments under international agreements. It was noted that phasing out coal-fired power plants by one-third will help Ontario achieve its goal of a 90 per cent reduction in mercury emissions by 2010. It was suggested that alternative power sources can offer a wide range of environmental advantages. 16 refs., 3 tabs., 2 figs

  19. Mercury(II) and methyl mercury speciation on Streptococcus pyogenes loaded Dowex Optipore SD-2

    Energy Technology Data Exchange (ETDEWEB)

    Tuzen, Mustafa, E-mail: m.tuzen@gmail.com [Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); Uluozlu, Ozgur Dogan [Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); Karaman, Isa [Gaziosmanpasa University, Faculty of Science and Arts, Biology Department, 60250 Tokat (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Science and Arts, Chemistry Department, 38039 Kayseri (Turkey)

    2009-09-30

    A solid phase extraction procedure based on speciation of mercury(II) and methyl mercury on Streptococcus pyogenes immobilized on Dowex Optipore SD-2 has been established. Selective and sequential elution with 0.1 mol L{sup -1} HCl for methyl mercury and 2 mol L{sup -1} HCl for mercury(II) were performed at pH 8. The determination of mercury levels was performed by cold vapour atomic absorption spectrometry (CVAAS). Optimal analytical conditions including pH, amounts of biosorbent, sample volumes, etc., were investigated. The influences of the some alkaline and earth alkaline ions and some transition metals on the recoveries were also investigated. The capacity of biosorbent for mercury(II) and methyl mercury was 4.8 and 3.4 mg g{sup -1}. The detection limit (3 sigma) of the reagent blank for mercury(II) and methyl mercury was 2.1 and 1.5 ng L{sup -1}. Preconcentration factor was calculated as 25. The relative standard deviations of the procedure were below 7%. The validation of the presented procedure is performed by the analysis of standard reference material (NRCC-DORM 2 Dogfish Muscle). The procedure was successfully applied to the speciation of mercury(II) and methyl mercury in natural water and environmental samples.

  20. Mercury(II) and methyl mercury speciation on Streptococcus pyogenes loaded Dowex Optipore SD-2

    International Nuclear Information System (INIS)

    Tuzen, Mustafa; Uluozlu, Ozgur Dogan; Karaman, Isa; Soylak, Mustafa

    2009-01-01

    A solid phase extraction procedure based on speciation of mercury(II) and methyl mercury on Streptococcus pyogenes immobilized on Dowex Optipore SD-2 has been established. Selective and sequential elution with 0.1 mol L -1 HCl for methyl mercury and 2 mol L -1 HCl for mercury(II) were performed at pH 8. The determination of mercury levels was performed by cold vapour atomic absorption spectrometry (CVAAS). Optimal analytical conditions including pH, amounts of biosorbent, sample volumes, etc., were investigated. The influences of the some alkaline and earth alkaline ions and some transition metals on the recoveries were also investigated. The capacity of biosorbent for mercury(II) and methyl mercury was 4.8 and 3.4 mg g -1 . The detection limit (3 sigma) of the reagent blank for mercury(II) and methyl mercury was 2.1 and 1.5 ng L -1 . Preconcentration factor was calculated as 25. The relative standard deviations of the procedure were below 7%. The validation of the presented procedure is performed by the analysis of standard reference material (NRCC-DORM 2 Dogfish Muscle). The procedure was successfully applied to the speciation of mercury(II) and methyl mercury in natural water and environmental samples.

  1. Human Exposure and Health Effects of Inorganic and Elemental Mercury

    Science.gov (United States)

    Zheng, Wei

    2012-01-01

    Mercury is a toxic and non-essential metal in the human body. Mercury is ubiquitously distributed in the environment, present in natural products, and exists extensively in items encountered in daily life. There are three forms of mercury, i.e., elemental (or metallic) mercury, inorganic mercury compounds, and organic mercury compounds. This review examines the toxicity of elemental mercury and inorganic mercury compounds. Inorganic mercury compounds are water soluble with a bioavailability of 7% to 15% after ingestion; they are also irritants and cause gastrointestinal symptoms. Upon entering the body, inorganic mercury compounds are accumulated mainly in the kidneys and produce kidney damage. In contrast, human exposure to elemental mercury is mainly by inhalation, followed by rapid absorption and distribution in all major organs. Elemental mercury from ingestion is poorly absorbed with a bioavailability of less than 0.01%. The primary target organs of elemental mercury are the brain and kidney. Elemental mercury is lipid soluble and can cross the blood-brain barrier, while inorganic mercury compounds are not lipid soluble, rendering them unable to cross the blood-brain barrier. Elemental mercury may also enter the brain from the nasal cavity through the olfactory pathway. The blood mercury is a useful biomarker after short-term and high-level exposure, whereas the urine mercury is the ideal biomarker for long-term exposure to both elemental and inorganic mercury, and also as a good indicator of body burden. This review discusses the common sources of mercury exposure, skin lightening products containing mercury and mercury release from dental amalgam filling, two issues that happen in daily life, bear significant public health importance, and yet undergo extensive debate on their safety. PMID:23230464

  2. Aerobic sulfide production and cadmium precipitation by Escherichia coli expressing the Treponema denticola cysteine desulfhydrase gene.

    Science.gov (United States)

    Wang, C L; Lum, A M; Ozuna, S C; Clark, D S; Keasling, J D

    2001-08-01

    The cysteine desulfhydrase gene of Treponema denticola was over-expressed in Escherichia coli to produce sulfide under aerobic conditions and to precipitate metal sulfide complexes on the cell wall. When grown in a defined salts medium supplemented with cadmium and cysteine, E. coli producing cysteine desulfhydrase secreted sulfide and removed nearly all of the cadmium from solution after 48 h. A control strain produced significantly less sulfide and removed significantly less cadmium. Measurement of acid-labile sulfide and energy dispersive X-ray spectroscopy indicated that cadmium was precipitated as cadmium sulfide. Without supplemental cysteine, both the E. coli producing cysteine desulfhydrase and the control E. coli demonstrated minimal cadmium removal.

  3. Sexual differences in the excretion of organic and inorganic mercury by methyl mercury-treated rats

    International Nuclear Information System (INIS)

    Thomas, D.J.; Fisher, H.L.; Sumler, M.R.; Mushak, P.; Hall, L.L.

    1987-01-01

    Adult male and female Long Evans rats received 1 mumole of methyl ( 203 Hg) mercuric chloride per kilogram sc. Whole-body retention of mercury and excretion of organic and inorganic mercury in urine and feces were monitored for 98 days after dosing. Females cleared mercury from the body more rapidly than did males. The major route of mercury excretion was feces. By 98 days after dosing, cumulative mercury excretion in feces accounted for about 51% of the dose in males and about 54% of the dose in females. For both sexes, about 33% of the dose was excreted in feces as inorganic mercury. Cumulative excretion of organic mercury in feces accounted for about 18 and 21% of the dose in males and females, respectively. Urinary excretion of mercury was quantitatively a smaller route for mercury clearance but important sexual differences in loss by this route were found. Over the 98-day experimental period, males excreted in urine about 3.2% of the dose and females excreted 7.5%. Cumulative organic Hg excretion in urine accounted for 1.8% of the dose in males and 5.3% of the dose in females. These sexual differences in urinary and fecal excretion of organic and inorganic mercury following methyl mercury treatment were consistent with previous reports of sexual differences in mercury distribution and retention in methyl mercury-treated rats, particularly sexual differences in organic mercury uptake and retention in the kidney. Relationships between body burdens of organic or inorganic Hg and output of these forms of Hg in urine and feces were also found to be influenced by the interval after MeHg treatment and by sex. Relationship between concentration of Hg in liver and feces and in kidney and urine differed for organic and inorganic Hg and depended upon sexual status and interval after MeHg treatment

  4. Electrical properties of seafloor massive sulfides

    Science.gov (United States)

    Spagnoli, Giovanni; Hannington, Mark; Bairlein, Katharina; Hördt, Andreas; Jegen, Marion; Petersen, Sven; Laurila, Tea

    2016-06-01

    Seafloor massive sulfide (SMS) deposits are increasingly seen as important marine metal resources for the future. A growing number of industrialized nations are involved in the surveying and sampling of such deposits by drilling. Drill ships are expensive and their availability can be limited; seabed drill rigs are a cost-effective alternative and more suitable for obtaining cores for resource evaluation. In order to achieve the objectives of resource evaluations, details are required of the geological, mineralogical, and physical properties of the polymetallic deposits and their host rocks. Electrical properties of the deposits and their ore minerals are distinct from their unmineralized host rocks. Therefore, the use of electrical methods to detect SMS while drilling and recovering drill cores could decrease the costs and accelerate offshore operations by limiting the amount of drilling in unmineralized material. This paper presents new data regarding the electrical properties of SMS cores that can be used in that assessment. Frequency-dependent complex electrical resistivity in the frequency range between 0.002 and 100 Hz was examined in order to potentially discriminate between different types of fresh rocks, alteration and mineralization. Forty mini-cores of SMS and unmineralized host rocks were tested in the laboratory, originating from different tectonic settings such as the intermediate-spreading ridges of the Galapagos and Axial Seamount, and the Pacmanus back-arc basin. The results indicate that there is a clear potential to distinguish between mineralized and non-mineralized samples, with some evidence that even different types of mineralization can be discriminated. This could be achieved using resistivity magnitude alone with appropriate rig-mounted electrical sensors. Exploiting the frequency-dependent behavior of resistivity might amplify the differences and further improve the rock characterization.

  5. Increased Mercury Bioaccumulation Follows Water Quality Improvement

    Energy Technology Data Exchange (ETDEWEB)

    Bogle, M.A.; Peterson, M.J.; Smith, J.G.; Southworth, G.R.

    1999-09-15

    Changes in physical and chemical characteristics of aquatic habitats made to reduce or eliminate ecological risks can sometimes have unforeseen consequences. Environmental management activities on the U.S. Dept. of Energy reservation in Oak Ridge, Tennessee,have succeeded in improving water quality in streams impacted by discharges fi-om industrial facilities and waste disposal sites. The diversity and abundance of pollution-sensitive components of the benthic macroinvertebrate communities of three streams improved after new waste treatment systems or remedial actions reduced inputs of various toxic chemicals. Two of the streams were known to be mercury-contaminated from historical spills and waste disposal practices. Waterborne mercury concentrations in the third were typical of uncontaminated systems. In each case, concentrations of mercury in fish, or the apparent biological availability of mercury increased over the period during which ecological metrics indicated improved water quality. In the system where waterborne mercury concentrations were at background levels, increased mercury bioaccumulation was probably a result of reduced aqueous selenium concentrations; however, the mechanisms for increased mercury accumulation in the other two streams remain under investigation. In each of the three systems, reduced inputs of metals and inorganic anions was followed by improvements in the health of aquatic invertebrate communities. However, this reduction in risk to aquatic invertebrates was accompanied by increased risk to humans and piscivorous wildlife related to increased mercury concentrations in fish.

  6. Increased Mercury Bioaccumulation Follows Water Quality Improvement

    International Nuclear Information System (INIS)

    Bogle, M.A.; Peterson, M.J.; Smith, J.G.; Southworth, G.R.

    1999-01-01

    Changes in physical and chemical characteristics of aquatic habitats made to reduce or eliminate ecological risks can sometimes have unforeseen consequences. Environmental management activities on the U.S. Dept. of Energy reservation in Oak Ridge, Tennessee,have succeeded in improving water quality in streams impacted by discharges fi-om industrial facilities and waste disposal sites. The diversity and abundance of pollution-sensitive components of the benthic macroinvertebrate communities of three streams improved after new waste treatment systems or remedial actions reduced inputs of various toxic chemicals. Two of the streams were known to be mercury-contaminated from historical spills and waste disposal practices. Waterborne mercury concentrations in the third were typical of uncontaminated systems. In each case, concentrations of mercury in fish, or the apparent biological availability of mercury increased over the period during which ecological metrics indicated improved water quality. In the system where waterborne mercury concentrations were at background levels, increased mercury bioaccumulation was probably a result of reduced aqueous selenium concentrations; however, the mechanisms for increased mercury accumulation in the other two streams remain under investigation. In each of the three systems, reduced inputs of metals and inorganic anions was followed by improvements in the health of aquatic invertebrate communities. However, this reduction in risk to aquatic invertebrates was accompanied by increased risk to humans and piscivorous wildlife related to increased mercury concentrations in fish

  7. A Challenging Case of Acute Mercury Toxicity

    Directory of Open Access Journals (Sweden)

    Ali Nayfeh

    2018-01-01

    Full Text Available Background. Mercury exists in multiple forms: elemental, organic, and inorganic. Its toxic manifestations depend on the type and magnitude of exposure. The role of colonoscopic decompression in acute mercury toxicity is still unclear. We present a case of acute elemental mercury toxicity secondary to mercury ingestion, which markedly improved with colonoscopic decompression. Clinical Case. A 54-year-old male presented to the ED five days after ingesting five ounces (148 cubic centimeters of elemental mercury. Examination was only significant for a distended abdomen. Labs showed elevated serum and urine mercury levels. An abdominal radiograph showed radiopaque material throughout the colon. Succimer and laxatives were initiated. The patient had recurrent bowel movements, and serial radiographs showed interval decrease of mercury in the descending colon with interval increase in the cecum and ascending colon. Colonoscopic decompression was done successfully. The colon was evacuated, and a repeat radiograph showed decreased hyperdense material in the colon. Three months later, a repeat radiograph showed no hyperdense material in the colon. Conclusion. Ingested elemental mercury can be retained in the colon. Although there are no established guidelines for colonoscopic decompression, our patient showed significant improvement. We believe further studies on this subject are needed to guide management practices.

  8. OCCURENCE OF MERCURY IN PET FOOD

    Directory of Open Access Journals (Sweden)

    M.C. Abete

    2013-02-01

    Full Text Available Mercury levels in 61 complete pet feed containing fish were evaluated. In five samples a mercury content exceeding the maximum residues level (0.4 mg/kg was detected. The statistical evaluation didn’t show a significant correlation between the percentage of fish in feedingstuffs and the contamination level.

  9. Hair mercury measurement in Egyptian autistic children

    African Journals Online (AJOL)

    Farida El-baz

    Abstract Background: A review of medical literature has shown that exposure to mercury, whether organic or inorganic, can give rise to the symptoms and traits defining or commonly found in autism spectrum disorders (ASD). Mercury can cause impairments in social interaction, commu- nication difficulties, and repetitive ...

  10. Terahertz oscillations in mercury cuprate superconductors

    Indian Academy of Sciences (India)

    Abstract. It has been recently reported that the three-dimensional Bose–Einstein con- densation of the quasi-particles is valid for the mercury cuprates at liquid helium tem- perature. In this study, the validity of the interlayer theory in three dimensions has been investigated for optimally oxygen-doped mercury cuprates at the ...

  11. Mercury poisoning | Shamley | South African Medical Journal

    African Journals Online (AJOL)

    The diagnosis of mercury poisoning requires a high index of suspicion. Mercury poisoning in a patient involved in illicit gold extraction is reported and 6 other cases considered. Some of the clinical features and treatment of this condition are discussed. S Afr Med J 1989; 76: 114-116 ...

  12. Mercury soil surveys: a good reconnaissance tool

    Energy Technology Data Exchange (ETDEWEB)

    Stone, C.; Ruscetta, C.A.; Foley, D. (eds.)

    1981-05-01

    Three examples of mercury soil surveys are discussed, along with the gravity data. An excellent correlation was found in southern Arizona between buried structures revealed by gravity and mercury soil surveys. The advantages of the latter over the former as a reconnaissance tool are listed. (MHR)

  13. Intentional intravenous mercury injection | Yudelowitz | South African ...

    African Journals Online (AJOL)

    Intravenous mercury injection is rarely seen, with few documented cases. Treatment strategies are not clearly defined for such cases, although a few options do show benefit. This case report describes a 29-year-old man suffering from bipolar disorder, who presented following self-inflicted intravenous injection of mercury.

  14. Pneumonitis after Inhalation of Mercury Vapours

    Directory of Open Access Journals (Sweden)

    JD Glezos

    2006-01-01

    Full Text Available A 43-year-old man presented to hospital with pneumonia but only after discharge from hospital did he admit to deliberate prior inhalation of mercury. His pulmonary involvement appeared to resolve almost completely with antibiotics and supportive care. Nevertheless, persisting elevated urinary excretion of mercury required two courses of chelation therapy. No serious systemic sequelae were observed.

  15. Recent Advances in Atmospheric Chemistry of Mercury

    Directory of Open Access Journals (Sweden)

    Lin Si

    2018-02-01

    Full Text Available Mercury is one of the most toxic metals and has global importance due to the biomagnification and bioaccumulation of organomercury via the aquatic food web. The physical and chemical transformations of various mercury species in the atmosphere strongly influence their composition, phase, transport characteristics and deposition rate back to the ground. Modeling efforts to assess global cycling of mercury require an accurate understanding of atmospheric mercury chemistry. Yet, there are several key uncertainties precluding accurate modeling of physical and chemical transformations. We focus this article on recent studies (since 2015 on improving our understanding of the atmospheric chemistry of mercury. We discuss recent advances in determining the dominant atmospheric oxidant of elemental mercury (Hg0 and understanding the oxidation reactions of Hg0 by halogen atoms and by nitrate radical (NO3—in the aqueous reduction of oxidized mercury compounds (HgII as well as in the heterogeneous reactions of Hg on atmospheric-relevant surfaces. The need for future research to improve understanding of the fate and transformation of mercury in the atmosphere is also discussed.

  16. Urban artisanal gold shops and mercury emissions

    International Nuclear Information System (INIS)

    Cordy, P.; Veiga, M.; Carrasco, V.H.G.

    2008-01-01

    Artisanal miners in developing countries use mercury amalgamation processes to extract gold. The amalgams are then refined before being sold on to urban gold shops. The amalgams can often contain between 2 to 40 per cent mercury. Unburned amalgams are also often sold directly to gold shops. There are serious health risks for shop employees and nearby populations when the gold is melted and further purified. Studies have shown that mercury concentrations in the ambient air of gold shops often exceeds World Health Organization (WHO) limits by an order of magnitude or more. This study examined the practices and technologies used to refine gold in Latin America and Indonesia. The study compared and contrasted various refining methods and their resulting mercury emissions. Methods of reducing mercury emissions were also investigated, including a filtration system designed to capture 80 per cent of mercury emissions. Barriers to implementing mercury emissions reduction plans were also investigated. It was concluded that the design of urban gold shops must include condensers, fume hoods, and efficient mercury capture systems. 15 refs

  17. Mercury cycling in peatland watersheds. Chapter 11.

    Science.gov (United States)

    Randall K. Kolka; Carl P.J. Mitchell; Jeffrey D. Jeremiason; Neal A. Hines; David F. Grigal; Daniel R. Engstrom; Jill K. Coleman-Wasik; Edward A. Nater; Edward B. Swain; Bruce A. Monson; Jacob A. Fleck; Brian Johnson; James E. Almendinger; Brian A. Branfireun; Patrick L. Brezonik; James B. Cotner

    2011-01-01

    Mercury (Hg) is of great environmental concern due to its transformation into the toxic methylmercury (MeHg) form that bioaccumulates within the food chain and causes health concerns for both humans and wildlife (U.S. Environmental Protection Agency 2002). Mercury can affect neurological development in fetuses and young children. In adults, exposure to Hg can lead to...

  18. Mercury in tropical and subtropical coastal environments

    Science.gov (United States)

    Costa, Monica F.; Landing, William M.; Kehrig, Helena A.; Barletta, Mário; Holmes, Christopher D.; Barrocas, Paulo R. G.; Evers, David C.; Buck, David G.; Vasconcellos, Ana Claudia; Hacon, Sandra S.; Moreira, Josino C.; Malm, Olaf

    2012-01-01

    Anthropogenic activities influence the biogeochemical cycles of mercury, both qualitatively and quantitatively, on a global scale from sources to sinks. Anthropogenic processes that alter the temporal and spatial patterns of sources and cycling processes are changing the impacts of mercury contamination on aquatic biota and humans. Human exposure to mercury is dominated by the consumption of fish and products from aquaculture operations. The risk to society and to ecosystems from mercury contamination is growing, and it is important to monitor these expanding risks. However, the extent and manner to which anthropogenic activities will alter mercury sources and biogeochemical cycling in tropical and sub-tropical coastal environments is poorly understood. Factors as (1) lack of reliable local/regional data; (2) rapidly changing environmental conditions; (3) governmental priorities and; (4) technical actions from supra-national institutions, are some of the obstacles to overcome in mercury cycling research and policy formulation. In the tropics and sub-tropics, research on mercury in the environment is moving from an exploratory “inventory” phase towards more process-oriented studies. Addressing biodiversity conservation and human health issues related to mercury contamination of river basins and tropical coastal environments are an integral part of paragraph 221 paragraph of the United Nations document “The Future We Want” issued in Rio de Janeiro in June 2012. PMID:22901765

  19. Episodic bioavailability of environmental mercury: implications for ...

    African Journals Online (AJOL)

    Perennial wildfires in Africa and other continents contribute an estimated 8 x 105 kg of mercury to the global atmosphere with a residence time of approximately one year. This phenomenon changes the flux of biologically available mercury in natural microbial communities where enzymatic actions, including mercuric ...

  20. Terahertz oscillations in mercury cuprate superconductors

    Indian Academy of Sciences (India)

    It has been recently reported that the three-dimensional Bose–Einstein condensation of the quasi-particles is valid for the mercury cuprates at liquid helium temperature. In this study, the validity of the interlayer theory in three dimensions has been investigated for optimally oxygen-doped mercury cuprates at the temperature ...

  1. Mercury in Thana creek, Bombay harbour

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Desai, B.N.

    Mercury content of the water column estimated along Thana Creek/Bombay Harbour gave a standing stock of about 77 kg in excess of the expected background. Mercury concentration in sediment from 23 locations which varied from 0.17 to 8.21 ppm (dry...

  2. Urban artisanal gold shops and mercury emissions

    Energy Technology Data Exchange (ETDEWEB)

    Cordy, P.; Veiga, M.; Carrasco, V.H.G. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Mining and Mineral Process Engineering

    2008-07-01

    Artisanal miners in developing countries use mercury amalgamation processes to extract gold. The amalgams are then refined before being sold on to urban gold shops. The amalgams can often contain between 2 to 40 per cent mercury. Unburned amalgams are also often sold directly to gold shops. There are serious health risks for shop employees and nearby populations when the gold is melted and further purified. Studies have shown that mercury concentrations in the ambient air of gold shops often exceeds World Health Organization (WHO) limits by an order of magnitude or more. This study examined the practices and technologies used to refine gold in Latin America and Indonesia. The study compared and contrasted various refining methods and their resulting mercury emissions. Methods of reducing mercury emissions were also investigated, including a filtration system designed to capture 80 per cent of mercury emissions. Barriers to implementing mercury emissions reduction plans were also investigated. It was concluded that the design of urban gold shops must include condensers, fume hoods, and efficient mercury capture systems. 15 refs.

  3. Mercury Sorption onto Malt Spent Rootlets

    Science.gov (United States)

    Manariotis, I. D.; Anagnostopoulos, V.; Karapanagioti, H. K.; Chrysikopoulos, C.

    2011-12-01

    Mercury is a metal of particular concern due to its toxicity even at relatively low concentrations. The maximum permissible level for mercury in drinking water set by the European Union is 0.001 mg/L. Mercury is released into the environment via four principal pathways: (1) natural processes; i.e. a volcanic eruption, (2) incidental to some other activity; i.e. coal burning power plants, (3) accidentally during the manufacture, breakage or disposal of products that have mercury put into them deliberately, and (4) direct use in industrial settings. The present study focuses on the removal of mercury (II) from aqueous solutions via sorption onto Malt Spent Rootlets (MSR). Batch experiments were conducted employing MSR with size ranging from 0.18 to 1 mm. The effects of pH, mercury concentration, contact time, and solid to liquid ratio on mercury sorption onto MSR were investigated. The highest mercury removal from the aqueous phase, of 41%, was observed at pH of 5.

  4. Low dose mercury toxicity and human health.

    Science.gov (United States)

    Zahir, Farhana; Rizwi, Shamim J; Haq, Soghra K; Khan, Rizwan H

    2005-09-01

    Post Minamata incident there has been awareness about mercury toxicity even among the general public. Previous researches contributed a vast amount of data regarding acute mercury exposure, but gradually information about the low dose [Ninomiya, T., Ohmori, H., Hashimoto, K., Tsuruta, K., Ekino, S., 1995. Expansion of methylmercury poisoning outside minamata: an epidemiological study on chronic methylmercury poisoninig outside of Minamata. Environ. Res. 70 (1) 47-50; Lebel, J., Mergler, D., Lucotte, M., Amorim, M., Dolbec, J., Miranda, D., Arantes, G., Rheault, I., Pichet, P., 1996. Evidence of early nervous system dysfunction in Amazonian populations exposed to low-levels of methylmercury. Neurotoxicology 17 (1) 157-167] of mercury toxicity has been trickling in. With mercury contaminating rain-, ground- and sea-water no one is safe. Polluted water leads to mercury laced fish, meat and vegetable. In aquatic environments, inorganic mercury is microbiologically transformed into lipophilic organic compound 'methylmercury'. This transformation makes mercury more prone to biomagnification in food chains. Consequently, populations with traditionally high dietary intake of food originating from fresh or marine environment have highest dietary exposure to mercury. Extensive research done on locals across the globe have already established this, persons who routinely consume fish or a particular species of fish are at an increased risk of methylmercury poisoning. The easy access of the toxicant to man through multiple pathways air, water, food, cosmetic products and even vaccines increase the exposure. Foetus and children are more susceptible towards mercury toxicity. Mothers consuming diet containing mercury pass the toxicant to foetus and to infants through breast milk. Decreased performance in areas of motor function and memory has been reported among children exposed to presumably safe mercury levels. Similarly, disruption of attention, fine motor function and verbal

  5. Synthesis of arsenic transition metal sulfides and metal arsenides

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, G.H.; Brown, L.D.; Ryan, D.F. [Exxon Research & Development Labs, Baton Rouge, LA (United States)

    1993-12-31

    One of the chief problems in upgrading shale oil is the presence of inherent arsenic which is known to poison downstream catalysts. Highly dispersed transition metal sulfides formed in situ from the decomposition of dithiocarbamate (DTC) complexes of transition metals show excellent potential as dearsenation agents. The authors have studied the reaction of these sulfides with various arsenic compositions and characterized the metal arsenides and arsenic metal sulfides formed as well as the ease of their formation. Thus, the reaction of bis(butyldithiocarbamato)Ni, (NiBuDTC) with model compounds was very facile and gave NiAs, NiAsS, and NiAs2=xSx. In general the effectiveness of the sulfides for dearsenation followed the sequence Ni>Mo{much_gt}Co, while iron sulfides were totally ineffective. Based upon these results, tests were run in autoclaves (as well as a fixed-bed flow-through unit) with NiBuDTC and shale oil having 73 ppm inherent As. Under optimum conditions, dearsenation down to les than 1 ppm was obtained.

  6. Solubility and permeation of hydrogen sulfide in lipid membranes.

    Directory of Open Access Journals (Sweden)

    Ernesto Cuevasanta

    Full Text Available Hydrogen sulfide (H(2S is mainly known for its toxicity but has recently been shown to be produced endogenously in mammalian tissues and to be associated with physiological regulatory functions. To better understand the role of biomembranes in modulating its biological distribution and effects; we measured the partition coefficient of H(2S in models of biological membranes. The partition coefficients were found to be 2.1±0.2, 1.9±0.5 and 2.0±0.6 in n-octanol, hexane and dilauroylphosphatidylcholine liposome membranes relative to water, respectively (25°C. This two-fold higher concentration of H(2S in the membrane translates into a rapid membrane permeability, P(m = 3 cm s(-1. We used a mathematical model in three dimensions to gain insight into the diffusion of total sulfide in tissues. This model shows that the sphere of action of sulfide produced by a single cell expands to involve more than 200 neighboring cells, and that the resistance imposed by lipid membranes has a significant effect on the diffusional spread of sulfide at pH 7.4, increasing local concentrations. These results support the role of hydrogen sulfide as a paracrine signaling molecule and reveal advantageous pharmacokinetic properties for its therapeutic applications.

  7. Effect of salinity on methylation of mercury

    Energy Technology Data Exchange (ETDEWEB)

    Blum, J.E.; Bartha, R.

    1980-09-01

    Monomethyl and dimethylmercury are potent neurotoxins subject to biomagnification in food webs. This fact was tragically demonstrated by the Minamata and Niigata poisoning incidents in Japan in which 168 persons who ate seafood from mercury polluted waters were poisoned, 52 fatally. Shortly after these two incidents, work conducted in freshwater environments demonstrated the microbial conversion of inorganic and phenylmercury compounds to mono- and di-methylmercury. Consideration of some fragmentary evidence from the literature, however, indicates that the rate and the significance of microbial methylation of mercury in freshwater and saltwater environments may not be the same. A demonstrated relationship between mercury methylation rates and water salinity would greatly influence our thinking about mercury pollution effects in marine versus freshwater environments. Since we were unable to locate published reports on this subject, we are investigating the influence of salinity on the rate of mercury methylation in an estuarine sediment.

  8. High activity carbon sorbents for mercury capture

    Directory of Open Access Journals (Sweden)

    Stavropoulos George G.

    2006-01-01

    Full Text Available High efficiency activated carbons have been prepared for removing mercury from gas streams. Starting materials used were petroleum coke, lignite, charcoal and olive seed waste, and were chemically activated with KOH. Produced adsorbents were primarily characterized for their porosity by N2 adsorption at 77 K. Their mercury retention capacity was characterized based on the breakthrough curves. Compared with typical commercial carbons, they have exhibited considerably enhanced mercury adsorption capacity. An attempt has been made to correlate mercury entrapment and pore structure. It has been shown that physical surface area is increased during activation in contrast to the mercury adsorption capacity that initially increases and tends to decrease at latter stages. Desorption of active sites may be responsible for this behavior.

  9. Human accumulation of mercury in Greenland

    DEFF Research Database (Denmark)

    Johansen, Poul; Mulvad, Gert; Pedersen, Henning Sloth

    2007-01-01

    In the Arctic, the traditional diet exposes its people to a high intake of mercury especially from marine mammals. To determine whether the mercury is accumulated in humans, we analyzed autopsy samples of liver, kidney and spleen from adult ethnic Greenlanders who died between 1990 and 1994 from...... a wide range of causes, natural and violent. Liver, kidney and spleen samples from between 33 and 71 case subjects were analyzed for total mercury and methylmercury, and liver samples also for selenium. Metal levels in men and women did not differ and were not related to age except in one case, i...... in liver and spleen and as little as 3% in kidney. In liver selenium was found in surplus to mercury on a molar basis. Mercury concentrations in the liver and kidneys of Greenlanders were elevated compared to levels in the general population in Japan, Korea and several European countries, except...

  10. Autism: a novel form of mercury poisoning.

    Science.gov (United States)

    Bernard, S; Enayati, A; Redwood, L; Roger, H; Binstock, T

    2001-04-01

    Autism is a syndrome characterized by impairments in social relatedness and communication, repetitive behaviors, abnormal movements, and sensory dysfunction. Recent epidemiological studies suggest that autism may affect 1 in 150 US children. Exposure to mercury can cause immune, sensory, neurological, motor, and behavioral dysfunctions similar to traits defining or associated with autism, and the similarities extend to neuroanatomy, neurotransmitters, and biochemistry. Thimerosal, a preservative added to many vaccines, has become a major source of mercury in children who, within their first two years, may have received a quantity of mercury that exceeds safety guidelines. A review of medical literature and US government data suggests that: (i) many cases of idiopathic autism are induced by early mercury exposure from thimerosal; (ii) this type of autism represents an unrecognized mercurial syndrome; and (iii) genetic and non-genetic factors establish a predisposition whereby thimerosal's adverse effects occur only in some children. Copyright 2001 Harcourt Publishers Ltd.

  11. Removal of mercury by adsorption: a review.

    Science.gov (United States)

    Yu, Jin-Gang; Yue, Bao-Yu; Wu, Xiong-Wei; Liu, Qi; Jiao, Fei-Peng; Jiang, Xin-Yu; Chen, Xiao-Qing

    2016-03-01

    Due to natural and production activities, mercury contamination has become one of the major environmental problems over the world. Mercury contamination is a serious threat to human health. Among the existing technologies available for mercury pollution control, the adsorption process can get excellent separation effects and has been further studied. This review is attempted to cover a wide range of adsorbents that were developed for the removal of mercury from the year 2011. Various adsorbents, including the latest adsorbents, are presented along with highlighting and discussing the key advancements on their preparation, modification technologies, and strategies. By comparing their adsorption capacities, it is evident from the literature survey that some adsorbents have shown excellent potential for the removal of mercury. However, there is still a need to develop novel, efficient adsorbents with low cost, high stability, and easy production and manufacture for practical utility.

  12. A large industrial pollution problem on the Kyrgyzstan - Uzbekistan border: Soviet production of mercury and stibium for the Soviet military

    International Nuclear Information System (INIS)

    Hadjamberdiev, I.; Tukhvatshin, R.

    2009-01-01

    Soviet industry of mercury and stibium was located in South-East Fergana in Kyrgyzstan and Uzbekistan boarder. Khaidarken combine produced high pure mercury (99.9997 percent) since 1940, it was the second source in the World (after Almadena, Spain). Maximal production was 790 t in 1990, after Transitional Shock about 300 tons a year. Tail was established in 1967. There is special tube 5500 m transporting pulp to tail. The pulp contains about 0,003 mg/liter mercury, 0,005 mg/liter arsenic, 21 mg/liter stibium, etc. Pulp is cleaned by aluminum sulfuric and mortar. After drying and compressing by itself the concentrations rises: mercury 90-250 mg/kg, arsenic 190-400, stibium 800-1700 mg/kg. Environment pollution problem contains three kinds: ground water infiltration; old tube corroding some places (leaking from chink of tube) - both mentioned lead to vegetables cumulating; combine work spreading mercury by air to settlement Khaidarken. Kadamjay enterprise for stibium (mines, combine, purify plant, tails) began work in 1936. Most part of production used in soviet military. Maximal production was 17.000 t clearing ore in 1990, after USSR collapse 1-6 t/year. Tremendous tails and dams (total 150 mln t) remains non re-cultivated until now. The tails contain electrolysis wastage: sodium-sulfides, sulfites, sulfates; stibium; arsenic; cadmium; stibium; etc. Seven deposits (tail-damp really) established 1976, total square 76.1 thousands sq m, total volume 250 thousand cub m. The deposits over-filled, contents filtrating - little saline or lakes generated (one situated 50m near Uzbekistan boarder). River Shakhimardan flow to Uzbekistan (settlement Vuadil, Ferghana town). There are health damage indices in the areas.(author)

  13. 21 CFR 862.3600 - Mercury test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mercury test system. 862.3600 Section 862.3600....3600 Mercury test system. (a) Identification. A mercury test system is a device intended to measure mercury, a heavy metal, in human specimens. Measurements obtained by this device are used in the diagnosis...

  14. 21 CFR 880.2920 - Clinical mercury thermometer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Clinical mercury thermometer. 880.2920 Section 880... Devices § 880.2920 Clinical mercury thermometer. (a) Identification. A clinical mercury thermometer is a... mercury. (b) Classification. Class II (special controls). The device is exempt from the premarket...

  15. Mercury flow experiments. 4th report: Measurements of erosion rate caused by mercury flow

    International Nuclear Information System (INIS)

    Kinoshita, Hidetaka; Kaminaga, Masanori; Haga, Katsuhiro; Hino, Ryutaro

    2002-06-01

    The Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting a construction plan of the Material-Life Science Facility, which is consisted of a Muon Science Facility and a Neutron Scattering Facility, in order to open up the new science fields. The Neutron Scattering Facility will be utilized for advanced fields of Material and Life science using high intensity neutron generated by the spallation reaction of a 1 MW pulsed proton beam and mercury target. Design of the spallation mercury target system aims to obtain high neutron performance with high reliability and safety. Since the target system is using mercury as the target material and contains large amount of radioactive spallation products, it is necessary to estimate reliability for strength of instruments in a mercury flow system during lifetime of the facility. Piping and components in the mercury flow system would be damaged by erosion with mercury flow, since these components will be weak by thickness decreasing. This report presents experimental results of wall thickness change by erosion using a mercury experimental loop. In the experiments, an erosion test section and coupons were installed in the mercury experimental loop, and their wall thickness was measured with an ultra sonic thickness gage after every 1000 hours. As a result, under 0.7 m/s of mercury velocity condition which is slightly higher than the practical velocity in mercury pipelines, the erosion is about 3 μm in 1000 hours. The wall thickness decrease during facility lifetime of 30 years is estimated to be less than 0.5 mm. According to the experimental result, it is confirmed that the effect of erosion on component strength is extremely small. Moreover, a measurement of residual mercury on the piping surface was carried out. As a result, 19 g/m 2 was obtained as the residual mercury for the piping surface. According to this result, estimated amount of residual mercury for

  16. Biomolecular Aspects of Mercury Transformations

    Science.gov (United States)

    Johs, A.; Shi, L.; Miller, S. M.; Summers, A. O.; Liang, L.

    2008-12-01

    Bacteria participate significantly in mercury transformation in natural and industrial environments. Previous studies have shown that bacterial mercury resistance is mediated by the mer operon, typically located on transposons or plasmids. It encodes specific genes that facilitate uptake of mercury species, cleavage of organomercurials, and reduction of Hg(II) to Hg(0). Expression of mer operon genes is regulated by MerR, a metal-responsive regulator protein on the level of transcription. In vitro studies have shown that MerR forms a non-transcribing pre-initiation complex with RNA polymerase and the promoter DNA. Binding of Hg(II) induces conformational changes in MerR and other components of the complex resulting in the transcription of mer operon genes. As part of ongoing investigations on allosteric conformational changes induced by Hg(II) in dimeric MerR, and the implications on the binding of RNA polymerase to the promoter of the mer operon, we applied small angle scattering to study the regulatory mechanism of MerR in the presence and absence of Hg(II). Our results show that in the presence of Hg(II) the MerR dimer undergoes a significant reorientation from a compact state to a conformation revealing two distinct domains. Bacterial reduction of Hg(II) can also occur at concentrations too low to induce mer operon functions. Dissimilatory metal reducing bacteria, such as Shewanella and Geobacter are able to reduce Hg(II) in the presence of mineral oxides. This process has been linked to the activity of outer membrane multiheme cytochromes. We isolated and purified a decaheme outer membrane cytochrome OmcA from Shewanella oneidensis MR-1 and characterized its envelope shape in solution by small angle x-ray scattering. Structural features were identified and compared to homology models. These results show that OmcA is an elongated macromolecule consisting of separate modules, which may be connected by flexible linkers.

  17. Mercury in food items from the Idrija Mercury Mine area.

    Science.gov (United States)

    Miklavčič, Ana; Mazej, Darja; Jaćimović, Radojko; Dizdarevi, Tatjana; Horvat, Milena

    2013-08-01

    As a consequence of over 500 years of mining and smelting activities (1490-1995), and of its natural geological occurrence, the soil in the Idrija region is highly contaminated with Hg. In order to assess the present situation regarding the Hg levels in local food samples, concentrations of total mercury (THg) and monomethyl mercury (MeHg) were determined in selected vegetables, mushrooms and fish from the Idrija Hg mine area. Hg levels in the foodstuffs analysed were not very high but were elevated compared to the levels in food from non-contaminated areas. The study showed that THg accumulates in mushrooms (X=5680ng/g dry weight, Min=346ng/g dry weight, Max=17,100 dry weight) and chicory (X=1950ng/g dry weight, Min=86ng/g dry weight, Max=17,100ng/g dry weight). In addition, Se and Cd concentrations were determined by ICP-MS in those vegetable and mushroom species in which the highest Hg levels were found. The levels of Cd and Se were below the threshold levels. Based on data from previous studies, we can conclude that the levels of Hg in food have not diminished significantly during the past 15 years after closure of the Hg mine. Special attention should be given to vegetables such as chicory, representing a local seasonal vegetable eaten frequently. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Estimating mercury emissions from a zinc smelter in relation to China's mercury control policies

    International Nuclear Information System (INIS)

    Wang, S.X.; Song, J.X.; Li, G.H.; Wu, Y.; Zhang, L.; Wan, Q.; Streets, D.G.; Chin, Conrad K.; Hao, J.M.

    2010-01-01

    Mercury concentrations of flue gas at inlet/outlet of the flue gas cleaning, electrostatic demister, reclaiming tower, acid plant, and mercury contents in zinc concentrate and by-products were measured in a hydrometallurgical zinc smelter. The removal efficiency of flue gas cleaning, electrostatic demister, mercury reclaiming and acid plant was about 17.4%, 30.3%, 87.9% and 97.4% respectively. Flue gas cleaning and electrostatic demister captured 11.7% and 25.3% of the mercury in the zinc concentrate, respectively. The mercury reclaiming tower captured 58.3% of the mercury in the zinc concentrate. About 4.2% of the mercury in the zinc concentrate was captured by the acid plant. Consequently, only 0.8% of the mercury in the zinc concentrate was emitted to the atmosphere. The atmospheric mercury emission factor was 0.5 g t -1 of zinc produced for the tested smelter, indicating that this process offers the potential to effectively reduce mercury emissions from zinc smelting. - Modern scale production equipped with acid plant and Hg reclaiming tower will significantly reduce Hg emissions from zinc smelters in China.

  19. Treatment of mercury containing waste

    Science.gov (United States)

    Kalb, Paul D.; Melamed, Dan; Patel, Bhavesh R; Fuhrmann, Mark

    2002-01-01

    A process is provided for the treatment of mercury containing waste in a single reaction vessel which includes a) stabilizing the waste with sulfur polymer cement under an inert atmosphere to form a resulting mixture and b) encapsulating the resulting mixture by heating the mixture to form a molten product and casting the molten product as a monolithic final waste form. Additional sulfur polymer cement can be added in the encapsulation step if needed, and a stabilizing additive can be added in the process to improve the leaching properties of the waste form.

  20. Geodesy at Mercury with MESSENGER

    Science.gov (United States)

    Smith, David E.; Zuber, Maria t.; Peale, Stanley J.; Phillips, Roger J.; Solomon, Sean C.

    2006-01-01

    In 2011 the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft will enter Mercury orbit and begin the mapping phase of the mission. As part of its science objectives the MESSENGER mission will determine the shape and gravity field of Mercury. These observations will enable the topography and the crustal thickness to be derived for the planet and will determine the small libration of the planet about its axis, the latter critical to constraining the state of the core. These measurements require very precise positioning of the MESSENGER spacecraft in its eccentric orbit, which has a periapsis altitude as low as 200 km, an apoapsis altitude near 15,000 km, and a closest approach to the surface varying from latitude 60 to about 70 N. The X-band tracking of MESSENGER and the laser altimetry are the primary data that will be used to measure the planetary shape and gravity field. The laser altimeter, which has an expected range of 1000 to 1200 km, is expected to provide significant data only over the northern hemisphere because of MESSENGER's eccentric orbit. For the southern hemisphere, radio occultation measurements obtained as the spacecraft passes behind the planet as seen from Earth and images obtained with the imaging system will be used to provide the long-wavelength shape of the planet. Gravity, derived from the tracking data, will also have greater resolution in the northern hemisphere, but full global models for both topography and gravity will be obtained at low harmonic order and degree. The limiting factor for both gravity and topography is expected to be knowledge of the spacecraft location. Present estimations are that in a combined tracking, altimetry, and occultation solution the spacecraft position uncertainty is likely to be of order 10 m. This accuracy should be adequate for establishing an initial geodetic coordinate system for Mercury that will enable positioning of imaged features on the surface, determination of

  1. Mercury migration into ground water, a literature study

    Energy Technology Data Exchange (ETDEWEB)

    Carlton, W.H.; Carden, J.L.; Kury, R.; Eichholz, G.G.

    1994-11-01

    This report presents a broad review of the technical literature dealing with mercury migration in the soil. The approach followed was to identify relevant articles by searching bibliographic data bases, obtaining the promising articles and searching these articles for any additional relevant citations. Eight catagories were used to organize the literature, with a review and summary of each paper. Catagories used were the following: chemical states of mercury under environmental conditions; diffusion of mercury vapor through soil; solubility and stability of mercury in environmental waters; transport of mercury on colloids; models for mercury migration through the environment; analytical techniques; retention of mercury by soil components; formation of organomecurials.

  2. Study of high levels indoor air mercury contamination from mercury amalgam use in dentistry

    International Nuclear Information System (INIS)

    Khwaja, M.A.; Abbasi, M.S.; Mehmood, F.; Jahangir, S.

    2014-01-01

    In 2005, United Nations Environment Programme (UNEP) estimated that 362 tonnes of dental mercury are consumed annually worldwide. Dental mercury amalgams also called silver fillings and amalgam fillings are widely done. These fillings gave off mercury vapours. Estimated average absorbed concentrations of mercury vapours from dental fillings vary from 3,000 to 17,000 ng Hg. Mercury (Hg) also known as quick silver is an essential constituent of dental amalgam. It is a toxic substance of global concern. A persistent pollutant, mercury is not limited to its source but it travels, on time thousands of kilometers away from the source. Scientific evidence, including, UNEP Global Mercury report, establishes mercury as an extremely toxic substance, which is a major threat to wildlife, ecosystem and human health, at a global scale. Children are more at risk from mercury poisoning which affects their neurological development and brain. Mercury poisoning diminishes memory, attention, thinking and sight. In the past, a number of studies at dental sites in many countries have been carried out and reported which have been reviewed and briefly described. This paper describes and discusses the recent investigations, regarding mercury vapours level in air, carried out at 18 dental sites in Pakistan and other countries. It is evident from the data of 42 dental sites in 17 countries, including, selected dental sites in five main cities of Pakistan, described and discussed in this paper that at most dental sites in many countries including Pakistan, the indoor mercury vapours levels exceed far above the permissible limit, recommended for safe physical and mental health. At these sites, public, in general, and the medical, paramedical staff and vulnerable population, in particular, are at most serious risk to health resulting from exposure to toxic and hazardous mercury. (author)

  3. Extraction of Nanosized Cobalt Sulfide from Spent Hydrocracking Catalyst

    Directory of Open Access Journals (Sweden)

    Samia A. Kosa

    2013-01-01

    Full Text Available The processes used for the extraction of metals (Co, Mo, and Al from spent hydrotreating catalysts were investigated in this study. A detailed mechanism of the metal extraction process is described. Additionally, a simulation study was performed to understand the sulfidizing mechanism. The suggested separation procedure was effective and achieved an extraction of approximately 80–90%. In addition, the sulfidization mechanism was identified. This sulfidizing process for Co was found to involve an intermediate, the structure of which was proposed. This proposed intermediate was confirmed through simulations. Moreover, the activities of the spent and the regenerated catalyst were examined in the cracking of toluene. The modification of the spent catalyst through the use of different iron oxide loadings improved the catalytic activity.

  4. Sulfide Catalysts Supported on Porous Aromatic Frameworks for Naphthalene Hydroprocessing

    Directory of Open Access Journals (Sweden)

    Eduard Karakhanov

    2016-08-01

    Full Text Available This paper describes the first example of using porous aromatic frameworks as supports for sulfide catalysts for the hydrogenation of aromatic hydrocarbons. The synthesis of bimetallic Ni-W and Ni-Mo sulfides was performed by in situ decomposition of [(n-Bu4N]2[Ni(MeS42] (Me = W, Mo complexes, supported on mesoporous aromatic framework with a diamond-like structure. It is shown that the highest naphthalene conversions were achieved in the case of additional sulfidation with sulfur. After the reaction, catalysts were characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. The activity of synthesized catalysts has been studied using naphthalene as a model substrate. The materials used in this study were substantially active in hydrogenation and slightly in hydrocracking of naphthalene.

  5. Preparation of transition metal sulfide nanoparticles via hydrothermal route

    International Nuclear Information System (INIS)

    Fei-Ling, P.; Chin-Hua, C.; Sarani Zakaria; Tze-Khong, L.; Mohd Ambar Yarmo; Nay-Ming, H.

    2010-01-01

    Nano sized copper sulfide, iron sulfide and molybdenum sulfide were successfully synthesised via a simple hydrothermal method. Sodium thiosulfate pentahydrate (Na 2 S 2 O 3 ·5H 2 O) and hydroxylamine sulfate ((H 3 NO) 2 ·H 2 SO 4 ) were used as the starting materials and reacted with the transition metal source at 200 degree Celsius for 90 min. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR). Spherical shape CuS and FeS 2 nanoparticles with high crystallinity were successfully produced. The transmission electron micrographs revealed the well-dispersibility of the produced nanoparticles. Scanning electron micrograph showed the MoS 2 nanoparticles possessed a spherical shape with sheet-like structure covering on the outer surface of the particles. (author)

  6. Metal sulfide electrodes and energy storage devices thereof

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Yet-Ming; Woodford, William Henry; Li, Zheng; Carter, W. Craig

    2017-02-28

    The present invention generally relates to energy storage devices, and to metal sulfide energy storage devices in particular. Some aspects of the invention relate to energy storage devices comprising at least one flowable electrode, wherein the flowable electrode comprises an electroactive metal sulfide material suspended and/or dissolved in a carrier fluid. In some embodiments, the flowable electrode further comprises a plurality of electronically conductive particles suspended and/or dissolved in the carrier fluid, wherein the electronically conductive particles form a percolating conductive network. An energy storage device comprising a flowable electrode comprising a metal sulfide electroactive material and a percolating conductive network may advantageously exhibit, upon reversible cycling, higher energy densities and specific capacities than conventional energy storage devices.

  7. Separation of platinum metals by theirs extraction as sulfides

    International Nuclear Information System (INIS)

    Pilipenko, A.T.; Ryabushko, O.P.; Ty Van Mak

    1978-01-01

    Separation of platinum metals by means of their sediment in the form of sulfides with subsequent extraction is studied. The optimum conditions of metal sulfide extraction are determined, the metal output dependence from acidness and aqueous phase composition and also the organic solvent nature are investigated. Ruthenium concentration was determined photometrically. Ruthenium sulfide is extracted by butyl spirit from 1-4 normal hydrochloric acid. The maximum extraction grade of 63% is reached in 3.2-normal acid. When the mixture of acetic and hydrochloric acids (2:1) is used for decomposition of ruthenium tiosalts, the grade of ruthenium extraction by amyl spirit or the mixture of anyl and butyl spirits (1:1) constitutes 100%

  8. Morphology and thermal studies of zinc sulfide and cadmium sulfide nanoparticles in polyvinyl alcohol matrix

    Science.gov (United States)

    Osuntokun, Jejenija; Ajibade, Peter A.

    2016-09-01

    Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato-κS,S'-bis(N,N-dimethylthiourea-κS) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33-7.21 nm for ZnS and 4.95-7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA.

  9. Morphology and thermal studies of zinc sulfide and cadmium sulfide nanoparticles in polyvinyl alcohol matrix

    Energy Technology Data Exchange (ETDEWEB)

    Osuntokun, Jejenija; Ajibade, Peter A., E-mail: pajibade@ufh.ac.za

    2016-09-01

    Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato–κS,S’–bis (N,N-dimethylthiourea–κS) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33–7.21 nm for ZnS and 4.95–7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA.

  10. ELECTROCHEMICAL DETERMINATION OF HYDROGEN SULFIDE AT CARBON NANOTUBE MODIFIED ELECTRODES. (R830900)

    Science.gov (United States)

    Carbon nanotube (CNT) modified glassy carbon electrodes exhibiting a strong and stable electrocatalytic response towards sulfide are described. A substantial (400 mV) decrease in the overvoltage of the sulfide oxidation reaction (compared to ordinary carbon electrodes) is...

  11. Substance Flow Analysis of Mercury in China

    Science.gov (United States)

    Hui, L. M.; Wang, S.; Zhang, L.; Wang, F. Y.; Wu, Q. R.

    2015-12-01

    In previous studies, the emission of anthropogenic atmospheric Hg in China as well as single sector have been examined a lot. However, there might have been more Hg released as solid wastes rather than air. Hg stored in solid wastes may be released to air again when the solid wastes experience high temperature process or cause local pollution if the solid wastes are stacked casually for a long time. To trace the fate of Hg in China, this study developed the substance flow of Hg in 2010 covering all the sectors summarized in table 1. Below showed in Figure 1, the total Hg input is 2825t. The unintentional input of Hg, mined Hg, and recycled Hg account for 57%, 32% and 11% respectively. Figure 2 provides the detail information of substance flow of Hg. Byproducts from one sector may be used as raw materials of another, causing cross Hg flow between sectors. The Hg input of cement production is 303 t, of which 34% comes from coal and limestone, 33% comes from non-ferrous smelting, 23% comes from coal combustion, 7% comes from iron and steel production and 3% comes from mercury mining. Hg flowing to recycledHg production is 639 t, mainly from Hg contained in waste active carbon and mercuric chloride catalyst from VCM production and acid sludge from non-ferrous smelting. There are 20 t mercury flowing from spent mercury adding products to incineration. Figure1 and Figure 2 also show that 46% of the output Hg belongs to "Lagged release", which means this part of mercury might be released later. The "Lagged release" Hg includes 809 t Hg contained in stacked byproducts form coal combustion, non-ferrous smelting, iron and steel production, Al production, cement production and mercury mining, 161t Hg stored in the pipeline of VCM producing, 10 t Hg in fluorescent lamps that are in use and 314 t mercury stored in materials waiting to be handled with in recycled mercury plants. There is 112 t Hg stored in landfill and 129 t Hg exported abroad with the export of mercury adding

  12. Mercury in the environment : a primer

    Energy Technology Data Exchange (ETDEWEB)

    Lourie, B.; Glenn, W. (ed.); Ogilvie, K.; Everhardus, E.; Friesen, K.; Rae, S.

    2003-06-01

    This report provides an overview of the occurrence and effects of mercury in the environment and its impacts on human health. Low levels of mercury occur naturally everywhere in the environment in plants, animals, rocks and air. Incidental emissions occur when natural mercury is released to the environment through human activity. In Canada, coal burning and metal processing are the two largest point sources of atmospheric mercury emissions. Energy facilities have the option to invest in expensive control technologies for coal plants, or they can generate electricity from alternative energy sources. Energy conservation, however, offers the greatest overall benefits for the environment and the public. Mercury can also be released when products containing mercury (such as electrical switches, thermostats, dental amalgam, and thermometers) are broken while in use, or when they are crushed in garbage trucks and dumped in landfills. Source separation is the best way to reduce waste-related emissions. Once mercury is released to the natural environment, it can be transported long distances through air or watercourses. It is volatile, therefore evaporates readily to the atmosphere where it may do one of three things: it may fall out near the point where it was emitted; it may be transported long distances to some point downwind; or, it may enter the global atmospheric mercury pool where it will circle the globe for a year or more within the Earth's major weather systems before being deposited. Data from Canada's National Pollutant Release Inventory indicates that mercury releases and transfers total 28,674 kg per year. The most critical component of the mercury cycle is the conversion of inorganic forms of mercury to the organic compound methylmercury which is more toxic to humans. Most concern about mercury focuses on lakes and other aquatic ecosystems. Fish in hydroelectric reservoirs have been found to contain elevated methylmercury levels because natural

  13. 40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units XIII Appendix XIII to Part 266 Protection of Environment... XIII to Part 266—Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units These...

  14. Groundwater Modeling of Mercury Pollution at a Former Mercury Cell Chlor Alkali Facility in Pavlodar City, Kazakhstan

    Science.gov (United States)

    In northern Kazakhstan, there is a serious case of mercury pollution near the city of Pavlodar from an old mercury cell chlor-alkali plant. The soil, sediment, and water is severely contaminated with mercury and mercury compounds as a result of the industrial activity of this ch...

  15. Biogeochemistry of mercury in contaminated environment in the wider Idrija region and the Gulf of Trieste. Highlights and achievements

    International Nuclear Information System (INIS)

    Horvat, Milena

    2002-01-01

    Activities at mercury (Hg) mines can lead to the mobilization of large quantities of Hg that enter the environment and are transported downstream. Although much of this Hg is deposited near the source, over time much of this Hg can be carried hundreds of kilometers where it can potentially enter and bioaccumulate in distant food webs. Mining activities in the ldrija, Slovenia mining district occurred for 500 years and the legacy of that mining can be seen in high concentrations of Hg throughout the watershed and into the Gulf of Trieste. Mercury concentrations are high in the sediments near the mouth of the Soca/Isonzo, River in the Gulf, and the Soca River continues to deliver ∼1.5 tons of Hg to the marine environment ∼100 km from the mine. Much of the Hg carried to the sea is probably as fine cinnabar particles, and the potential remobilization and further transformation of this Hg is of concern with regard to local environmental and the accumulation of methylmercury (MeHg in seafood. Mercury sulfide minerals are subject to dissolution and increased bioavailability when they contact sulfidic environments such as what occurs in coastal marine sediments. This 'newly' available Hg can potentially undergo methylation to supply the environment with newly formed MeHg. Indeed, Gulf sediments contain significant concentrations of MeHg and effluxes of MeHg from Gulf sediments have been observed in recent studies. However, sediments can also support active demethylation by aerobic and anaerobic bacteria. This demethylation can be due to either oxidative or reductive pathways. The present study was conducted to determine the potential of sediments from the Gulf of Trieste to methylate and demethylate Hg including an assessment of which demethylation pathway is most prevalent

  16. Handbook of Phase Transition Sulfides, Selenides and Tellurides,

    Science.gov (United States)

    1984-07-01

    Cinnabar) ........ A-108 In2S3 (Indium Sulfide or 01-Indium Trisulfide) ...... A-113 MnS (Manganese Monosulfide) ... .... .. .......... A-116 - MnS2...1n2S 3 Indium Sulfide or Di-Indium Trisulflde In2S3 exists as cubic a-In 2S3 and tetragonal 0-In 2S3. Until recently, no detailed studies on the...structure and the vibrational properties of In2S3 have been reported. 0-In 2S3 is the stable room temperature phase. At 420°C there is a transition to c

  17. High conducting oxide--sulfide composite lithium superionic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chengdu; Rangasamy, Ezhiylmurugan; Dudney, Nancy J.; Keum, Jong Kahk; Rondinone, Adam Justin

    2017-01-17

    A solid electrolyte for a lithium-sulfur battery includes particles of a lithium ion conducting oxide composition embedded within a lithium ion conducting sulfide composition. The lithium ion conducting oxide composition can be Li.sub.7La.sub.3Zr.sub.2O.sub.12 (LLZO). The lithium ion conducting sulfide composition can be .beta.-Li.sub.3PS.sub.4 (LPS). A lithium ion battery and a method of making a solid electrolyte for a lithium ion battery are also disclosed.

  18. Experimental constraints on gold and silver solubility in iron sulfides

    International Nuclear Information System (INIS)

    Pal'yanova, Galina; Mikhlin, Yuri; Kokh, Konstantin; Karmanov, Nick; Seryotkin, Yurii

    2015-01-01

    Experiments were performed to determine crystallization of Fe,S-melts (pyriti≿ and troilitic with molar ratio S/Fe ratios of 2 and 1, respectively) containing traces of gold and silver at (Ag/Au) wt ratios varying from 10 to 0.1. The solid products were studied by optical microscopy, scanning electron microscopy, X-ray powder diffraction (XRD), microprobe analysis, and X-ray photoelectron spectroscopy (XPS) in order to reveal the concentration limits of “invisible” gold and silver in magmatic iron sulfides, and to determine the influence of sulfur on forms of precious metals in the Fe–S system with different Ag/Au ratios. Au–Ag phases do not form inclusions but instead concentrate on the grain boundaries in the synthetic pyrrhotite and troilite, while pyrite comprises micro- (1–5 μm) and macroinclusions of Au–Ag alloys and Au–Ag sulfides. In “pyriti≿” systems, the fineness of alloys increases from 650 to 970‰ and the composition of sulfides changes from acanthite (Ag 2 S) to uytenbogaardtite (Ag 3 AuS 2 ) and petrovskaite (AgAuS) as the Ag/Au ratio decreases. The concentrations of “invisible” precious metals revealed in troilite were 0.040 ± 0.013 wt.% Au and 0.079 ± 0.016 wt.% Ag. Measured concentrations in pyrite and pyrrhotite were <0.024 wt.% Au and <0.030 wt.% Ag. The surface layers of iron sulfides probed with XPS were enriched in the precious metals, and in silver relative to gold, especially in the systems with Fe/S = 1, probably, due to depletion of the metallic alloy surfaces with gold. Au- and Ag-bearing iron sulfides crystallized primarily from melts may be the source of redeposited phases in hydrothermal and hypergene processes. - Highlights: • The samples of Fe–S–Au–Ag system were synthesized. • Coupled solubility of gold and silver in iron sulfides was specified. • Ag–Au inclusions on surfaces of iron sulfides are likely to be enriched in silver. • Au–Ag sulfides can exist along with native gold in

  19. Thermal stability of semiconductor sulfide phases in air

    International Nuclear Information System (INIS)

    Tsiulyanv, I.I.; Lyalikova, K.Y.; Zhitar, V.F.

    1986-01-01

    This paper investigates the semiconductor sulfide phases Zn 3 In 2 S 6 , Zn 3 Ga 2 S 6 , and Zn 3 GaInS 6 , produced by chemical transport reactions in a sealed space. A typical derivatogram is shown. Up to 873 K no weight changes appear in the TG curve. As indium atoms are replaced by gallium atoms the kinetic oxidation parameters of the sulfide phases change regularly, and they correlate with the calculated heat of atomization, which characterizes bond strength. The dependence of the temperature of the start of oxidation on composition shows that zinc thiogallate is the most stable when heated in air

  20. Dental amalgam and urinary mercury concentrations: a descriptive study

    OpenAIRE

    Nicolae, Alexandra; Ames, Harry; Qui?onez, Carlos

    2013-01-01

    Background Dental amalgam is a source of elemental and inorganic mercury. The safety of dental amalgam in individuals remains a controversial issue. Urinary mercury concentrations are used to assess chronic exposure to elemental mercury. At present, there are no indications of mercury-associated adverse effects at levels below 5??g Hg/g creatinine (Cr) or 7??g Hg/L (urine). The purpose of the present study is to determine the overall urinary mercury level in the Canadian general population in...

  1. Electrocatalysis of the hydrogen evolution reaction by thermally formed sulfides on steels

    OpenAIRE

    Kumar, Prem T; Sathyanarayana, S

    1990-01-01

    The electrocatalytic activity was studied of sulfides, formed by thermal sulfidization of various com. available steels, for the cathodic evolution of H from sodium chloride. The effects of certain surface active anions on the H evolution reaction on these sulfidized steels were also studied. Sulfidization of C steels and Si steels increases their electrocatalytic activity with respect to cathodic H evolution and thereby reduces the over potential in sodium chloride solns. (typically about ...

  2. Mercury's magnetosphere and magnetotial revisited

    International Nuclear Information System (INIS)

    Bergan, S.; Engle, I.M.

    1981-01-01

    Magnetic observations which are not complicated by currents of trapped plasma are a good test of geomagnetopause and geomagnetotail predictions. Recent attempts to model the Hermean magnetospheric field based on a planet-centered magnetic multipole field with a quadrupole moment in addition to the planetary dipole field or a dipole field linearly displaced from planet center and no quadrupole moment have produced reasonably good fits to the Mercury magnetic field measurements. In this work we find a better fit for a dipole displacement from the planet center by making use of an improved representation of the magnetic field in the magnetotail, where many of the Mercury measurements were made. The rms deviation of the data was reduced from 10. or 11. γ to 9.3 γ by employing this new tail field representation. Also, by making use of this new tail field representation, we find a best fit for a dipole displacement of -0.0285 R/sub M/ (earlier, 0.026 R/sub M/) toward the dawn in the magnetic equatorial plane and 0.17 R/sub M/ (earlier, 0.189 R/sub M/ (earlier 0.189 R/sub M/) northward along the magnetic dipole axis, where R/sub M/ is the planet radius. Thus with only minor adjustments in the displacement vector of the dipole from the planet center we achieve a measurable improvement in the fit of the data by using the improved magnetotail field representation

  3. The solubility of iron sulfides and their role in mass transport in Girdler-Sulfide heavy water plants

    International Nuclear Information System (INIS)

    Tewari, P.H.; Wallace, G.; Campbell, A.B.

    1978-04-01

    The solubilities of several iron sulfides, mackinawite FeSsub((1-x)), troilite FeS, pyrrhotite Fesub((1-x))S (monoclinic and hexagonal), and pyrite FeS 2 have been determined in aqueous H 2 S solution at 0.1 MPa and 1.8 MPa H 2 S pressures between 25 deg and 125 deg C. The dependence of solubility on the pH of the medium has also been studied. It is concluded that since mackinawite is the most soluble of the iron sulfides, and has the highest dissolution rate and the steepest decline in solubility with temperature, its prolonged formation during plant operation should be avoided to minimize iron transport from lower to higher temperature areas in Girdler-Sulfide (G.S.) heavy water plants. This can be achieved by a preconditioning of carbon steel surfaces to convert mackinawite to pyrrhotite and pyrite

  4. A thin, dense crust for Mercury

    Science.gov (United States)

    Sori, Michael M.

    2018-05-01

    Crustal thickness is a crucial geophysical parameter in understanding the geology and geochemistry of terrestrial planets. Recent development of mathematical techniques suggests that previous studies based on assumptions of isostasy overestimated crustal thickness on some of the solid bodies of the solar system, leading to a need to revisit those analyses. Here, I apply these techniques to Mercury. Using MESSENGER-derived elemental abundances, I calculate a map of grain density (average 2974 ± 89 kg/m3) which shows that Pratt isostasy is unlikely to be a major compensation mechanism of Mercury's topography. Assuming Airy isostasy, I find the best fit value for Mercury's mean crustal thickness is 26 ± 11 km, 25% lower than the most recently reported and previously thinnest number. Several geological implications follow from this relatively low value for crustal thickness, including showing that the largest impacts very likely excavated mantle material onto Mercury's surface. The new results also show that Mercury and the Moon have a similar proportion of their rocky silicates composing their crusts, and thus Mercury is not uniquely efficient at crustal production amongst terrestrial bodies. Higher resolution topography and gravity data, especially for the southern hemisphere, will be necessary to refine Mercury's crustal parameters further.

  5. Elimination of mercury from amalgam in rats

    Energy Technology Data Exchange (ETDEWEB)

    Galic, N. [Dept. of Dental Pathology, School of Dentistry, Zagreb (Croatia); Prpic-Mehicic, G.; Prester, Lj.; Blanusa, M. [Inst. for Medical Research and Occupational Health, Zagreb (Croatia); Krnic, Z.; Erceg, D. [Pliva Pharmaceutical Co., Biomedicine Research Inst. ' ' Pliva' ' , Zagreb (Croatia)

    2001-07-01

    The aim of this study was to measure the urinary mercury excretion in rats exposed to amalgam over a two months period. Animals were either exposed to mercury from 4 dental amalgams or fed the diet containing powdered amalgams. The results showed significantly higher mercury amount in urine of both exposed groups than in control. Even two months after the amalgam had been placed in rats teeth, the amount of mercury in the urine remained 4-5 times higher than in control, and 4 times higher than in rats exposed to diet containing powdered amalgam. The elevated urinary Hg amount was accompanied by an increased level of total protein in urine. In the same exposure period the excretion of total protein in urine of rats with amalgam fillings was 2 times higher than in control and 1.5 times higher than in rats exposed to amalgam through diet. Concentrations of mercury in the sera of all groups were below the detection limit of the method. The results show that amount of mercury and protein in the urine of rats were related to the mercury release from dental amalgam. (orig.)

  6. Mercury flow experiments. 4th report Measurements of erosion rate caused by mercury flow

    CERN Document Server

    Kinoshita, H; Hino, R; Kaminaga, M

    2002-01-01

    The Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting a construction plan of the Material-Life Science Facility, which is consisted of a Muon Science Facility and a Neutron Scattering Facility, in order to open up the new science fields. The Neutron Scattering Facility will be utilized for advanced fields of Material and Life science using high intensity neutron generated by the spallation reaction of a 1 MW pulsed proton beam and mercury target. Design of the spallation mercury target system aims to obtain high neutron performance with high reliability and safety. Since the target system is using mercury as the target material and contains large amount of radioactive spallation products, it is necessary to estimate reliability for strength of instruments in a mercury flow system during lifetime of the facility. Piping and components in the mercury flow system would be damaged by erosion with mercury flow, since these components will be we...

  7. Concentration of mercury in wheat samples stored with mercury tablets as preservative

    International Nuclear Information System (INIS)

    Lalit, B.Y.; Ramachandran, T.V.

    1977-01-01

    Tablets consisting of mercury in the form of a dull grey powder made by triturating mercury with chalk and sugar are used in Indian household for storing food-grains. The contamination of wheat samples by mercury, when stored with mercury tablets for period of upto four years has been assessed by using non-destructive neutron activation analysis. The details of the analytical procedure used have also been briefly described. The concentration of mercury in wheat increases with storage period. Loss of weight of mercury tablet is proportional to the storage period to a first approximation. In the present experiment, the average weight loss at the and end of first year was 0.009716 g corresponding to 6 ppm in wheat. (T.G.)

  8. SULFIDE OXIDATION UNDER OXYGEN LIMITATION BY A THIOBACILLUS-THIOPARUS ISOLATED FROM A MARINE MICROBIAL MAT

    NARCIS (Netherlands)

    VANDENENDE, FP; VANGEMERDEN, H

    1993-01-01

    The colorless sulfur bacterium Thiobacillus thioparus T5, isolated from a marine microbial mat, was grown in continuous culture under conditions ranging from sulfide limitation to oxygen limitation. Under sulfide-limiting conditions, sulfide was virtually completely oxidized to sulfate. Under

  9. Reliability of Electrochemical Techniques for Determining Corrosion Rates on Carbon Steel in Sulfide Media

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, T.; Nielsen, Lars Vendelbo

    2007-01-01

    Effects of film formation on carbon steel in hydrogen sulfide (H2S) media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from H2S solutions, biological sulfide media, and natural sulfide containing geothermal water have been collected, and the process of...

  10. Sulfide-iron interactions in domestic wastewater from a gravity sewer

    NARCIS (Netherlands)

    Nielsen, A.H.; Lens, P.N.L.; Vollertsen, J.; Hvitved-Jacobsen, Th.

    2005-01-01

    Interactions between iron and sulfide in domestic wastewater from a gravity sewer were investigated with particular emphasis on redox cycling of iron and iron sulfide formation. The concentration ranges of iron and total sulfide in the experiments were 0.4-5.4 mg Fe L-1 and 0-5.1 mg S L-1,

  11. Is succession in wet calcareous dune slacks affected by free sulfide?

    NARCIS (Netherlands)

    Adema, EB; van Gemerden, H; Grootjans, AP; Adema, Erwin B.; Grootjans, Ab P.; Rapson, G.

    Consequences of sulfide toxicity on succession in wet calcareous dune slacks were investigated. Sulfide may exert an inhibitory effect on dune slack plants, but several pioneer species exhibit ROL (Radial Oxygen Loss) and thereby protect themselves against free sulfide. Under oxic conditions free

  12. Identifying the Prospective Area of Sulfide Groundwater within the Area of Palvantash Oil and Gas Deposit

    Directory of Open Access Journals (Sweden)

    M. R. Zhurayev

    2014-03-01

    Full Text Available This paper describes the methodology of prospecting for sulfide groundwater in the area of Palvantash oil fields. In result of study allowed determining the favorable conditions for the sulfide waters formation, and mapping the areas of different sulfide water concentration. The relatively permeable areas were established and the water borehole positions were recommended.

  13. 76 FR 69136 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

    Science.gov (United States)

    2011-11-08

    ... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for Hydrogen Sulfide; Correction. SUMMARY: The... Administrative Stay of the reporting requirements for hydrogen sulfide. The Office of the Federal Register...

  14. Hidden sources of mercury in clinical laboratories.

    Science.gov (United States)

    Alvarez-Chavez, C R; Federico-Perez, R A; Gomez-Alvarez, A; Velazquez-Contreras, L E; Perez-Rios, R

    2014-09-01

    The healthcare sector is an important contributor to mercury (Hg) pollution because of the potential presence of mercury in thermometers, blood pressure cuffs, amalgams, etc. There are also other potential sources of mercury in this sector which are used frequently and in high volumes where the presence of the metal is not obvious and which might be collectively contributing to pollution. For instance, some chemicals used for the clinical diagnosis of illness may contain mercury. The goal of this study was to investigate potential sources of mercury pollution, which originate from clinical laboratory discharges, using an exploratory approach. The focus was on the residue generated during automatic analysis of patients' bodily fluids at a medical center in Hermosillo, Sonora, Mexico. This study shows an overview of what might be happening in the region or the country related to non-obvious sources of mercury in the healthcare sector. The results showed measurable levels of mercury in the residues coming from urine sediment analysis. These amounts do not exceed the maximum allowed by Mexican environmental regulations; nevertheless, the frequency and cumulative volume of residues generated, combined with the potential for persistence and the bioaccumulation of mercury in the environment, warrant attention. The work carried out in this study is being taken as a model for future studies for pollution prevention in the healthcare sector with the goal of measuring mercury emissions to the environment from clinical laboratory wastewater, including identifying sources which--while not obvious--could be important given the frequency and volume of their use in the clinical diagnosis.

  15. Trace hydrogen sulfide gas sensor based on tungsten sulfide membrane-coated thin-core fiber modal interferometer

    Science.gov (United States)

    Deng, Dashen; Feng, Wenlin; Wei, Jianwei; Qin, Xiang; Chen, Rong

    2017-11-01

    A novel fiber-optic hydrogen sulfide sensor based on a thin-core Mach-Zehnder fiber modal interferometer (TMZFI) is demonstrated and fabricated. This in-line interferometer is composed of a short section of thin-core fiber sandwiched between two standard single mode fibers, and the fast response to hydrogen sulfide is achieved via the construction of tungsten sulfide film on the outside surface of the TMZFI using the dip-coating and calcination technique. The fabricated sensing nanofilm is characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) spectrometer, Fourier transform infrared (FTIR) and spectroscopic analysis technology, etc. Experimental results showed that the WS2 sensing film has a hexagonal structure with a compact and porous morphology. The XPS and FTIR indicate that the existence of two elements (W and S) is demonstrated. With the increasing concentration of hydrogen sulfide, the interference spectra appear blue shift. In addition, a high sensitivity of 18.37 pm/ppm and a good linear relationship are obtained within a measurement range from 0 to 80 ppm. In addition, there is an excellent selectivity for H2S, which has also been proved by the surface adsorption energy results of tungsten sulfide with four gases (H2S, N2, O2 and CO2) by using the density functional theory calculations. This interferometer has the advantages of simple structure, high sensitivity and easy manufacture, and could be used in the safety monitoring field of hydrogen sulfide gas.

  16. The tropical African mercury anomaly: lower than expected mercury concentrations in fish and human hair.

    Science.gov (United States)

    Black, Frank J; Bokhutlo, Thethela; Somoxa, Aaron; Maethamako, Mothusi; Modisaemang, Ontlogetse; Kemosedile, Thebe; Cobb-Adams, Cristina; Mosepele, Ketlhatlogile; Chimbari, Moses

    2011-04-15

    Mercury is a neurotoxin and global pollutant, and wetlands and newly flooded areas are known to be sites of enhanced production of monomethylmercury, the form of mercury that is readily biomagnified in aquatic food chains to potentially toxic levels. The Okavango Delta in Botswana, Southern Africa, is the largest inland delta in the world and a wetland ecosystem that experiences dramatic annual flooding of large tracts of seasonal floodplains. The Delta was, therefore, expected to be home to high mercury levels in fish and to be an area where local subsistence fishing communities would be at substantial risk of mercury toxicity from fish consumption. Total mercury concentrations measured in 27 species of fish from the Okavango Delta averaged (mean±s.d., wet weight) 19±19ng g(-1) in non-piscivorous fish, and 59±53ng g(-1) in piscivorous fish. These mercury concentrations are similar to those reported for fish from lakes in other areas of tropical Africa, demonstrating that not all wetlands are sites of elevated mercury concentrations in biota. Even more intriguing is that concentrations of mercury in fish from across tropical Africa are systematically and substantially lower than those typically reported for fish from freshwater ecosystems elsewhere globally. The reasons for this apparent "African mercury anomaly" are unclear, but this finding poses a unique opportunity to improve our understanding of mercury's biogeochemical cycling in the environment. Mercury concentrations measured in human hair collected in subsistence fishing communities in the Okavango Delta were similarly low (0.21±0.22μg g(-1) dry weight) despite high levels of fish consumption, and reflect the low mercury concentrations in the fish here. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Methyl mercury, but not inorganic mercury, associated with higher blood pressure during pregnancy.

    Science.gov (United States)

    Wells, Ellen M; Herbstman, Julie B; Lin, Yu Hong; Hibbeln, Joseph R; Halden, Rolf U; Witter, Frank R; Goldman, Lynn R

    2017-04-01

    Prior studies addressing associations between mercury and blood pressure have produced inconsistent findings; some of this may result from measuring total instead of speciated mercury. This cross-sectional study of 263 pregnant women assessed total mercury, speciated mercury, selenium, and n-3 polyunsaturated fatty acids in umbilical cord blood and blood pressure during labor and delivery. Models with a) total mercury or b) methyl and inorganic mercury were evaluated. Regression models adjusted for maternal age, race/ethnicity, prepregnancy body mass index, neighborhood income, parity, smoking, n-3 fatty acids and selenium. Geometric mean total, methyl, and inorganic mercury concentrations were 1.40µg/L (95% confidence interval: 1.29, 1.52); 0.95µg/L (0.84, 1.07); and 0.13µg/L (0.10, 0.17), respectively. Elevated systolic BP, diastolic BP, and pulse pressure were found, respectively, in 11.4%, 6.8%, and 19.8% of mothers. In adjusted multivariable models, a one-tertile increase of methyl mercury was associated with 2.83mmHg (0.17, 5.50) higher systolic blood pressure and 2.99mmHg (0.91, 5.08) higher pulse pressure. In the same models, an increase of one tertile of inorganic mercury was associated with -1.18mmHg (-3.72, 1.35) lower systolic blood pressure and -2.51mmHg (-4.49, -0.53) lower pulse pressure. No associations were observed with diastolic pressure. There was a non-significant trend of higher total mercury with higher systolic blood pressure. We observed a significant association of higher methyl mercury with higher systolic and pulse pressure, yet higher inorganic mercury was significantly associated with lower pulse pressure. These results should be confirmed with larger, longitudinal studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Isolation, screening and identification of mercury resistant bacteria from mercury contaminated soil

    OpenAIRE

    Kowalczyk Anna; Wilińska Magdalena; Chyc Marek; Bojko Monika; Latowski Dariusz

    2016-01-01

    New bacterial strains resistant to high concentration of mercury were obtained and character iz ed focusing on their potential application in bioremediation. The biological material was isolated from soil contaminated with mercury. The ability to removal of Hg from the liquid medium and the effect of the various pH and mercury concentrations in the environment on bacterial strains growth kinetics were tested. The selected strains were identified by analysis of the 16S ribosome subunit coding ...

  19. Mercury fluxes through the sediment water interface and bioavailability of mercury in southern Baltic Sea sediments

    Directory of Open Access Journals (Sweden)

    Jacek Bełdowski

    2009-06-01

    Full Text Available Sediment cores collected in several areas of the southern Baltic were analysed for total mercury (HgTOT and five operationally defined mercury fractions: HgA - contained in pore waters, HgF - bound to fulvic acids, HgH - bound to humic acids, HgS - bound to sulphide, and HgR - residual. An effort was made to quantify mercury fluxes at the sediment/water interface in the study area. Net mercury input, calculated on the basis of sedimentation rate and concentration in the uppermost sediments, ranged from 1 to 5.5 ng cm-2 year-1. Mercury remobilisation from sediments due to diffusion and resuspension was calculated from the proportion of labile mercury and the velocity of near-bottom currents. The results showed that the return soluble and particulate fluxes of mercury from the sediments to the water column constitute a substantial proportion of the input (20-50%, and are slightly higher than those found in pristine areas, although they are less than the values recorded in areas with a history of mercury contamination. In addition, an index was developed to assess the methylation potential of mercury in sediments. Mercury contained in pore waters, and mercury bound to fulvic and humic acids together with Loss on Ignition were used to calculate the semi-quantitative methylation potential (Pm. Despite the simplicity of this approach, Pm correlates well with methyl mercury in fish from the study area.full, complete article (PDF - compatibile with Acrobat 4.0, 291.3 kB

  20. determination of mercury content in milk powder

    International Nuclear Information System (INIS)

    Jovchev, M.; Grigorov, T.; Apostolov, D.

    1985-01-01

    Four samples of humanized full cream cow milk powder of Bulgarian origin for new-born, sucklings, small children and soured milk powder were activated for 18-24 h in a neutron flux of 5.10 12 , resp. 2.10 13 n/cm 2 .sec in quartz ampules. The samples were activated without preliminary lyophilization, thus avoiding possible mistakes from mercury losses. Ag-110m, being eliminated in the amalgam, was not an obstacle to the mercury determination. The results obtained for the mercury content are in the same order as in other investigations and many times lower than the admissible norm for foodstuffs - 50 ppb

  1. Effect of mercury on algal growth rates

    Energy Technology Data Exchange (ETDEWEB)

    Hannan, P.J.; Patouillet, C.

    1972-01-01

    In experiments with one freshwater (Chlorella pyrenoidosa) and three marine organisms (Phaeodactylum tricornutum, Cyclotella nana, and Chaetoceras gavestonensis), mercury was more toxic than the other metals tested (silver, cadmium, lead, and copper); and its toxicity is comparatively irreversible. Growth was monitored by changes in fluorescence of the cultures over a 3-day test period. The toxicity of the mercury varied inversely with the concentrations of nutrients present. Preliminary experiments indicate that mercury in the form of mercuric chloride is more toxic than as dimethylmercury. 12 references, 3 figures, 1 table.

  2. Conditioning of spent mercury by amalgamation

    International Nuclear Information System (INIS)

    Yim, S. P.; Shon, J. S.; An, B. G.; Lee, H. J.; Lee, J. W.; Ji, C. G.; Kim, S. H.; Yoon, J. H.; Yang, M. S.

    2002-01-01

    Solidification by amalgamation was performed to immobilize and stabilize the liquid spent mercury. First, the appropriate metal and alloy which can convert liquid mercury into a solid form of amalgam were selected through initial tests. The amalgam form, formulated in optimum composition, was characterized and subjected to performance tests including compressive strength, water immersion, leachability and initial vaporization rate to evaluate mechanical integrity, durability and leaching properties. Finally, bench scale amalgamation trial was conducted with about 1 kg of spent mercury to verify the feasibility of amalgamation method

  3. A self-focusing mercury jet target

    CERN Document Server

    Johnson, C

    2002-01-01

    Mercury jet production targets have been studied in relation to antiproton production and, more recently, pion production for a neutrino factory. There has always been a temptation to include some self-focusing of the secondaries by passing a current through the mercury jet analogous to the already proven lithium lens. However, skin heating of the mercury causes fast vaporization leading to the development of a gliding discharge along the surface of the jet. This external discharge can, nevertheless, provide some useful focusing of the secondaries in the case of the neutrino factory. The technical complications must not be underestimated.

  4. Mercury Thermal Hydraulic Loop (MTHL) Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Felde, David K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Crye, Jason Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wendel, Mark W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yoder, Jr, Graydon L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Farquharson, George [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jallouk, Philip A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McFee, Marshall T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pointer, William David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ruggles, Art E. [Univ. of Tennessee, Knoxville, TN (United States); Carbajo, Juan J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-03-01

    The Spallation Neutron Source (SNS) is a high-power linear accelerator built at Oak Ridge National Laboratory (ORNL) which incorporates the use of a flowing liquid mercury target. The Mercury Thermal Hydraulic Loop (MTHL) was constructed to investigate and verify the heat transfer characteristics of liquid mercury in a rectangular channel. This report provides a compilation of previously reported results from the water-cooled and electrically heated straight and curved test sections that simulate the geometry of the window cooling channel in the target nose region.

  5. Physical properties of the planet Mercury

    Science.gov (United States)

    Clark, Pamela E.

    1988-01-01

    The global physical properties of Mercury are summarized with attention given to its figure and orbital parameters. The combination of properties suggests that Mercury has an extensive iron-rich core, possibly with a still-functioning dynamo, which is 42 percent of the interior by volume. Mercury's three major axes are comparable in size, indicating that the planet is a triaxial ellipsoid rather than an oblate spheroid. In terms of the domination of its surface by an intermediate plains terrane, it is more Venus- or Mars-like; however, due to the presence of a large metallic magnetic core, its interior may be more earth-like.

  6. MESSENGER'S First and Second Flybys of Mercury

    Science.gov (United States)

    Slavin, James A.

    2009-01-01

    The MESSENGER mission to Mercury offers our first opportunity to explore this planet's miniature magnetosphere since Mariner 10's brief fly-bys in 1974-5. The magnetosphere of Mercury is the smallest in the solar system with its magnetic field typically standing off the solar wind only approximately 1000 km above the surface. An overview of the MESSENGER mission and its January 14th and October 6th, 2008 close flybys of Mercury will be provided. Primary science objectives and the science instrumentation will be described. Initial results from MESSENGER will be discussed with an emphasis on the magnetic field and charged particle measurements.

  7. Photochemical reactions between mercury (Hg) and dissolved organic matter decrease Hg bioavailability and methylation.

    Science.gov (United States)

    Luo, Hong-Wei; Yin, Xiangping; Jubb, Aaron M; Chen, Hongmei; Lu, Xia; Zhang, Weihua; Lin, Hui; Yu, Han-Qing; Liang, Liyuan; Sheng, Guo-Ping; Gu, Baohua

    2017-01-01

    Atmospheric deposition of mercury (Hg) to surface water is one of the dominant sources of Hg in aquatic environments and ultimately drives methylmercury (MeHg) toxin accumulation in fish. It is known that freshly deposited Hg is more readily methylated by microorganisms than aged or preexisting Hg; however the underlying mechanism of this process is unclear. We report that Hg bioavailability is decreased by photochemical reactions between Hg and dissolved organic matter (DOM) in water. Photo-irradiation of Hg-DOM complexes results in loss of Sn(II)-reducible (i.e. reactive) Hg and up to an 80% decrease in MeHg production by the methylating bacterium Geobacter sulfurreducens PCA. Loss of reactive Hg proceeded at a faster rate with a decrease in the Hg to DOM ratio and is attributed to the possible formation of mercury sulfide (HgS). These results suggest a new pathway of abiotic photochemical formation of HgS in surface water and provide a mechanism whereby freshly deposited Hg is readily methylated but, over time, progressively becomes less available for microbial uptake and methylation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Injurious effect of mercury vapor from bichloride of mercury in soil of rose houses

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, P.W.; Crocker, W.

    1933-01-01

    Addition of mercuric chloride, or corrosive sublimate, to Rose soil for killing earthworms may injure the Roses. The organic matter of the soil reduces the bichloride to metallic mercury and the vapors of the mercury rise into the air and kill the buds and peduncles. When the soil is rich in tankage or other organic matter, the rate of reduction of the bichloride is increased and thereby the severity of the injury intensified. If a container of metallic mercury is set in an enclosed chamber with Rose plants, severe injuries of the type mentioned below soon appear. The Briarcliff Rose is especially susceptible to mercury injury. 1 figure.

  9. Mercury Information Clearinghouse. Quarterly 3: advanced and developmental mercury control technologies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    Advanced mercury control technologies for coal-fired electric utilities are reviewed. The technologies evaluated are at various stages of development and most have been tested under limited operational conditions. The following technologies are described: K-Fuel and K-Fuel Plus pre-combustion technology, combustion modification and in situ generation of sorbents, new sorbent developments, direct bromine injection, MerCAP{sup {trademark}} (Mercury Control via Adsorption Process, Gore felt filter bag inserts, EnviroScrub Pahlman{sup {trademark}} process, combined oxidation of NO{sub x} and mercury, and mercury control with the Advanced Hybrid{trademark} filter. 36 refs., 1 fig.

  10. Solubility of helium in mercury for bubbling technology of the spallation neutron mercury target

    International Nuclear Information System (INIS)

    Hasegawa, S.; Naoe, T.; Futakawa, M.

    2010-01-01

    The pitting damage of mercury target container that originates in the pressure wave excited by the proton beam incidence becomes a large problem to reach the high-power neutron source in JSNS and SNS. The lifetime of mercury container is decreased remarkably by the pitting damage. As one of solutions, the pressure wave is mitigated by injecting the helium micro bubbles in mercury. In order to inject the helium micro bubbles into mercury, it is important to understand the characteristic of micro bubbles in mercury. The solubility of mercury-helium system is a key factor to decide bubbling conditions, because the disappearance behavior, i.e. the lifetime of micro bubbles, depends on the solubility. In addition, the bubble generation method is affected by it. Moreover, the experimental data related to the solubility of helium in mercury hardly exist. In this work, the solubility was obtained experimentally by measuring precisely the pressure drop of the gas that is facing to mercury surface. The pressure drop was attributed to the helium dissolution into mercury. Based on the measured solubility, the lifetime of micro bubbles and the method of the bubble generation is estimated using the solubility data.

  11. Inorganic mercury exposure, mercury-copper interaction, and DMPS treatment in rats.

    OpenAIRE

    Blanusa, M; Prester, L; Radić, S; Kargacin, B

    1994-01-01

    The aim of this study was to evaluate the efficiency of oral treatment with sodium 2,3-dimercaptopropane-1-sulfonate (DMPS) on reducing mercury deposits in rat kidney after chronic exposure to inorganic mercury. The effect on kidney copper levels was also evaluated. The results showed that after two months of exposure to 50 ppm of mercury (as mercuric chloride) the concentration of mercury in the kidney was 124 micrograms/g wet tissue. At the same time copper concentration rose from 11 to 77 ...

  12. Mercury nano-trap for effective and efficient removal of mercury(II) from aqueous solution

    Science.gov (United States)

    Li, Baiyan; Zhang, Yiming; Ma, Dingxuan; Shi, Zhan; Ma, Shengqian

    2014-11-01

    Highly effective and highly efficient decontamination of mercury from aqueous media remains a serious task for public health and ecosystem protection. Here we report that this task can be addressed by creating a mercury ‘nano-trap’ as illustrated by functionalizing a high surface area and robust porous organic polymer with a high density of strong mercury chelating groups. The resultant porous organic polymer-based mercury ‘nano-trap’ exhibits a record-high saturation mercury uptake capacity of over 1,000 mg g-1, and can effectively reduce the mercury(II) concentration from 10 p.p.m. to the extremely low level of smaller than 0.4 p.p.b. well below the acceptable limits in drinking water standards (2 p.p.b.), and can also efficiently remove >99.9% mercury(II) within a few minutes. Our work therefore presents a new benchmark for mercury adsorbent materials and provides a new perspective for removing mercury(II) and also other heavy metal ions from contaminated water for environmental remediation.

  13. Tundra uptake of atmospheric elemental mercury drives Arctic mercury pollution

    Science.gov (United States)

    Obrist, Daniel; Agnan, Yannick; Jiskra, Martin; Olson, Christine L.; Colegrove, Dominique P.; Hueber, Jacques; Moore, Christopher W.; Sonke, Jeroen E.; Helmig, Detlev

    2017-07-01

    Anthropogenic activities have led to large-scale mercury (Hg) pollution in the Arctic. It has been suggested that sea-salt-induced chemical cycling of Hg (through ‘atmospheric mercury depletion events’, or AMDEs) and wet deposition via precipitation are sources of Hg to the Arctic in its oxidized form (Hg(II)). However, there is little evidence for the occurrence of AMDEs outside of coastal regions, and their importance to net Hg deposition has been questioned. Furthermore, wet-deposition measurements in the Arctic showed some of the lowest levels of Hg deposition via precipitation worldwide, raising questions as to the sources of high Arctic Hg loading. Here we present a comprehensive Hg-deposition mass-balance study, and show that most of the Hg (about 70%) in the interior Arctic tundra is derived from gaseous elemental Hg (Hg(0)) deposition, with only minor contributions from the deposition of Hg(II) via precipitation or AMDEs. We find that deposition of Hg(0)—the form ubiquitously present in the global atmosphere—occurs throughout the year, and that it is enhanced in summer through the uptake of Hg(0) by vegetation. Tundra uptake of gaseous Hg(0) leads to high soil Hg concentrations, with Hg masses greatly exceeding the levels found in temperate soils. Our concurrent Hg stable isotope measurements in the atmosphere, snowpack, vegetation and soils support our finding that Hg(0) dominates as a source to the tundra. Hg concentration and stable isotope data from an inland-to-coastal transect show high soil Hg concentrations consistently derived from Hg(0), suggesting that the Arctic tundra might be a globally important Hg sink. We suggest that the high tundra soil Hg concentrations might also explain why Arctic rivers annually transport large amounts of Hg to the Arctic Ocean.

  14. Tundra uptake of atmospheric elemental mercury drives Arctic mercury pollution.

    Science.gov (United States)

    Obrist, Daniel; Agnan, Yannick; Jiskra, Martin; Olson, Christine L; Colegrove, Dominique P; Hueber, Jacques; Moore, Christopher W; Sonke, Jeroen E; Helmig, Detlev

    2017-07-12

    Anthropogenic activities have led to large-scale mercury (Hg) pollution in the Arctic. It has been suggested that sea-salt-induced chemical cycling of Hg (through 'atmospheric mercury depletion events', or AMDEs) and wet deposition via precipitation are sources of Hg to the Arctic in its oxidized form (Hg(ii)). However, there is little evidence for the occurrence of AMDEs outside of coastal regions, and their importance to net Hg deposition has been questioned. Furthermore, wet-deposition measurements in the Arctic showed some of the lowest levels of Hg deposition via precipitation worldwide, raising questions as to the sources of high Arctic Hg loading. Here we present a comprehensive Hg-deposition mass-balance study, and show that most of the Hg (about 70%) in the interior Arctic tundra is derived from gaseous elemental Hg (Hg(0)) deposition, with only minor contributions from the deposition of Hg(ii) via precipitation or AMDEs. We find that deposition of Hg(0)-the form ubiquitously present in the global atmosphere-occurs throughout the year, and that it is enhanced in summer through the uptake of Hg(0) by vegetation. Tundra uptake of gaseous Hg(0) leads to high soil Hg concentrations, with Hg masses greatly exceeding the levels found in temperate soils. Our concurrent Hg stable isotope measurements in the atmosphere, snowpack, vegetation and soils support our finding that Hg(0) dominates as a source to the tundra. Hg concentration and stable isotope data from an inland-to-coastal transect show high soil Hg concentrations consistently derived from Hg(0), suggesting that the Arctic tundra might be a globally important Hg sink. We suggest that the high tundra soil Hg concentrations might also explain why Arctic rivers annually transport large amounts of Hg to the Arctic Ocean.

  15. 21 CFR 177.2490 - Polyphenylene sulfide resins.

    Science.gov (United States)

    2010-04-01

    ... contact with food at temperatures up to and including normal baking and frying temperatures; provided that... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyphenylene sulfide resins. 177.2490 Section 177.2490 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...

  16. An eco-friendly oxidation of sulfide compounds

    Indian Academy of Sciences (India)

    An improved green route has been developed for the oxidation of sulfide compounds. Albendazole is converted to ricobendazole or albendazole sulfone using H₂O₂ as an oxidant and H₂O as the solvent. High yields of the corresponding products were obtained by carrying out the reaction at room temperature.

  17. Micelle Mediated Trace Level Sulfide Quantification through Cloud Point Extraction

    Directory of Open Access Journals (Sweden)

    Samrat Devaramani

    2012-01-01

    Full Text Available A simple cloud point extraction protocol has been proposed for the quantification of sulfide at trace level. The method is based on the reduction of iron (III to iron (II by the sulfide and the subsequent complexation of metal ion with nitroso-R salt in alkaline medium. The resulting green-colored complex was extracted through cloud point formation using cationic surfactant, that is, cetylpyridinium chloride, and the obtained surfactant phase was homogenized by ethanol before its absorbance measurement at 710 nm. The reaction variables like metal ion, ligand, surfactant concentration, and medium pH on the cloud point extraction of the metal-ligand complex have been optimized. The interference effect of the common anions and cations was studied. The proposed method has been successfully applied to quantify the trace level sulfide in the leachate samples of the landfill and water samples from bore wells and ponds. The validity of the proposed method has been studied by spiking the samples with known quantities of sulfide as well as comparing with the results obtained by the standard method.

  18. Hydrogen sulfide : role in vascular physiology and pathology

    NARCIS (Netherlands)

    Holwerda, Kim M.; Karumanchi, S. Ananth; Lely, A. Titia

    Purpose of reviewHydrogen sulfide (H2S), a colorless gas that is endogenously generated in mammals from cysteine, has important biological functions. Within the vasculature it regulates vessel tone and outgrowth of new vessels. This review summarizes recent literature on H2S signaling in the

  19. Diuretic action of exogenous hydrogen sulfide in spontaneously ...

    African Journals Online (AJOL)

    Diuretic action of exogenous hydrogen sulfide in spontaneously hypertensive diabetic rats. F ud Din Ahmad, MA Sattar, HA Rathore, S Akhter, O Hui Jin, EJ Johns. Abstract. Purpose: To examine the hypothesis that in hypertensive diabetic rats hydrogen sulphide (H2S) reduces blood pressure through diuretic action in ...

  20. Luminescence in Sulfides: A Rich History and a Bright Future

    Directory of Open Access Journals (Sweden)

    Philippe F. Smet

    2010-04-01

    Full Text Available Sulfide-based luminescent materials have attracted a lot of attention for a wide range of photo-, cathodo- and electroluminescent applications. Upon doping with Ce3+ and Eu2+, the luminescence can be varied over the entire visible region by appropriately choosing the composition of the sulfide host. Main application areas are flat panel displays based on thin film electroluminescence, field emission displays and ZnS-based powder electroluminescence for backlights. For these applications, special attention is given to BaAl2S4:Eu, ZnS:Mn and ZnS:Cu. Recently, sulfide materials have regained interest due to their ability (in contrast to oxide materials to provide a broad band, Eu2+-based red emission for use as a color conversion material in white-light emitting diodes (LEDs. The potential application of rare-earth doped binary alkaline-earth sulfides, like CaS and SrS, thiogallates, thioaluminates and thiosilicates as conversion phosphors is discussed. Finally, this review concludes with the size-dependent luminescence in intrinsic colloidal quantum dots like PbS and CdS, and with the luminescence in doped nanoparticles.

  1. CARBONYL SULFIDE INHALATION PRODUCES BRAIN LESIONS IN F344 RATS.

    Science.gov (United States)

    Carbonyl sulfide (COS) is an intermediate in the production of pesticides and herbicides, and is a metabolite of the neurotoxicant carbon disulfide. The potential neurotoxicity of inhaled COS was investigated in F344 rats. Male rats were exposed to 0, 75, 150, 300, or 600 ppm COS...

  2. Geology of volcanogenic massive sulfide deposit near Meli ...

    African Journals Online (AJOL)

    Bheema

    Chloritization is the dominant alteration among others, and the ore body is associated with mafic to intermediate ... attracted both national and international mineral exploration companies to search for the metallic ... metal sulfides are attracting the attention of many exploration companies like, National Mining. Company ...

  3. Carbon-supported iron and iron-molybdenum sulfide catalysts

    International Nuclear Information System (INIS)

    Ramselaar, W.L.T.M.

    1988-01-01

    The main objective was to describe the relations between the characteristics (composition and dispersion) of the actual sulfide phase and the catalytic activity. Attention was also paid to the influence of preparational aspects on these characteristics. The catalysts were characterized using in-situ Moessbauer spectroscopy down to 2.0 K. 254 refs.; 47 figs.; 22 tabs

  4. Transition Metal Sulfide Hydrogen Evolution Catalysts for Hydrobromic Acid Electrolysis

    NARCIS (Netherlands)

    Ivanovskaya, Anna; Singh, Nirala; Liu, Ru-Fen; Kreutzer, Haley; Baltrusaitis, Jonas; Nguyen, Trung Van; Metiu, Horia; McFarland, Eric

    2013-01-01

    Mixed metal sulfides containing combinations of W, Fe, Mo, Ni, and Ru were synthesized and screened for activity and stability for the hydrogen evolution reaction (HER) in aqueous hydrobromic acid (HBr). Co- and Ni-substituted RuS2 were identified as potentially active HER electrocatalysts by

  5. The Complex Resistivity Spectrum Characteristics About Stratabound Sulfide Deposits

    Science.gov (United States)

    Dong, P.; Sun, B.; Wang, L.; Chen, Z.; Dong, Z.; Wu, Y.

    2010-12-01

    Complex resistivity method has become the key technique of deep prospecting, and widely applied in stratabound sulfide deposits which often form massive ores. However, the complex resistivity spectrum characteristics of stratabound sulfide deposits remains unknown. Through studying variation problem of two-dimensional polarization medium, deducing the differential equations and calculating formula,we applied Cole-Cole model to deduce the spectrum of complex resistivity based on the model of three-node and four-node finite element method, and programmed homologous procedure. We utilized the Earth Model of Geological Layers which has accurate analytical solution to test rationality and accuracy of our modeling. We applied the layer structure provided by drilling results in Chenmenshan copper mine,which is typical strata-bound sulfide deposits in Jiangxi province,China, and calculated the spectra of complex resistivity, then made comparison between modeled and measured values. We find good corellation between them. Our studies may have imporved the interpretation of complex resistivity data, which help apply complex resistivity methods of propecting on stratabound sulfide deposites.

  6. Support Effect in the Hydrodesulfurization of Thiophene over Rhodium Sulfide

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Vít, Zdeněk; Zdražil, Miroslav

    2010-01-01

    Roč. 101, č. 1 (2010), s. 63-72 ISSN 1878-5190 R&D Projects: GA ČR GA104/09/0751 Institutional research plan: CEZ:AV0Z40720504 Keywords : hydrodesulfurization * thiophene * rhodium sulfide Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  7. Bio-reduction of sulfide minerals to recover invisible gold

    NARCIS (Netherlands)

    Hol, A.

    2011-01-01

      Sulfide minerals, like pyrite and arsenopyrite, are of economical interest due to the presence of invisible gold locked inside these minerals. As fine grinding is often not sufficient to liberate the gold from these minerals, additional destruction techniques, based on chemical and

  8. New Findings in Hydrogen Sulfide Related Corrosion of Concrete Sewers

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Jensen, Henriette Stokbro; Hvitved-Jacobsen, Thorkild

    2009-01-01

    This paper summarizes major findings of a long-term study of hydrogen sulfide gas (H2S) adsorption and oxidation on concrete and plastic sewer pipe surfaces. The processes have been studied using a pilot-scale setup designed to replicate conditions in a gravity sewer located downstream of a force...

  9. Sulfide Concentration and Redox Potential Patterns in Mangrove ...

    African Journals Online (AJOL)

    The conclusion of these results is that spatial and temporal variation in the soil redox potential and sulfide concentrations, which are results of microbial activities in the sediment, influence mangrove seedling establishment. These soil factors are modified by the root systems, whereby sediments in areas with plenty of ...

  10. Luminescence in Sulfides: A Rich History and a Bright Future

    Science.gov (United States)

    Smet, Philippe F.; Moreels, Iwan; Hens, Zeger; Poelman, Dirk

    2010-01-01

    Sulfide-based luminescent materials have attracted a lot of attention for a wide range of photo-, cathodo- and electroluminescent applications. Upon doping with Ce3+ and Eu2+, the luminescence can be varied over the entire visible region by appropriately choosing the composition of the sulfide host. Main application areas are flat panel displays based on thin film electroluminescence, field emission displays and ZnS-based powder electroluminescence for backlights. For these applications, special attention is given to BaAl2S4:Eu, ZnS:Mn and ZnS:Cu. Recently, sulfide materials have regained interest due to their ability (in contrast to oxide materials) to provide a broad band, Eu2+-based red emission for use as a color conversion material in white-light emitting diodes (LEDs). The potential application of rare-earth doped binary alkaline-earth sulfides, like CaS and SrS, thiogallates, thioaluminates and thiosilicates as conversion phosphors is discussed. Finally, this review concludes with the size-dependent luminescence in intrinsic colloidal quantum dots like PbS and CdS, and with the luminescence in doped nanoparticles.

  11. Rapid biosynthesis of cadmium sulfide (CdS) nanoparticles using ...

    African Journals Online (AJOL)

    Rapid biosynthesis of cadmium sulfide (CdS) nanoparticles using culture supernatants of Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633 and Lactobacillus ... The process of extracellular and fast biosynthesis may help in the development of an easy and eco-friendly route for the synthesis of CdS nanoparticles.

  12. Iridium Sulfide and Ir Promoted Mo Based Catalysts.

    Czech Academy of Sciences Publication Activity Database

    Vít, Zdeněk

    2007-01-01

    Roč. 322, - (2007), s. 142-151 ISSN 0926-860X R&D Projects: GA ČR(CZ) GA104/06/0870 Institutional research plan: CEZ:AV0Z40720504 Keywords : iridium sulfide * IrMo catalyst * hydrodesulfurization Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.166, year: 2007

  13. Estimation of bacterial hydrogen sulfide production in vitro

    Directory of Open Access Journals (Sweden)

    Amina Basic

    2015-06-01

    Full Text Available Oral bacterial hydrogen sulfide (H2S production was estimated comparing two different colorimetric methods in microtiter plate format. High H2S production was seen for Fusobacterium spp., Treponema denticola, and Prevotella tannerae, associated with periodontal disease. The production differed between the methods indicating that H2S production may follow different pathways.

  14. Rethinking mercury: the role of selenium in the pathophysiology of mercury toxicity.

    Science.gov (United States)

    Spiller, Henry A

    2018-05-01

    There is increasing evidence that the pathophysiological target of mercury is in fact selenium, rather than the covalent binding of mercury to sulfur in the body's ubiquitous sulfhydryl groups. The role of selenium in mercury poisoning is multifaceted, bidirectional, and central to understanding the target organ toxicity of mercury. An initial search was performed using Medline/PubMed, Toxline, Google Scholar, and Google for published work on mercury and selenium. These searches yielded 2018 citations. Publications that did not evaluate selenium status or evaluated environmental status (e.g., lake or ocean sediment) were excluded, leaving approximately 500 citations. This initial selection was scrutinized carefully and 117 of the most relevant and representative references were selected for use in this review. Binding of mercury to thiol/sulfhydryl groups: Mercury has a lower affinity for thiol groups and higher affinity for selenium containing groups by several orders of magnitude, allowing for binding in a multifaceted way. The established binding of mercury to thiol moieties appears to primarily involve the transport across membranes, tissue distribution, and enhanced excretion, but does not explain the oxidative stress, calcium dyshomeostasis, or specific organ injury seen with mercury. Effects of mercury on selenium and the role this plays in the pathophysiology of mercury toxicity: Mercury impairs control of intracellular redox homeostasis with subsequent increased intracellular oxidative stress. Recent work has provided convincing evidence that the primary cellular targets are the selenoproteins of the thioredoxin system (thioredoxin reductase 1 and thioredoxin reductase 2) and the glutathione-glutaredoxin system (glutathione peroxidase). Mercury binds to the selenium site on these proteins and permanently inhibits their function, disrupting the intracellular redox environment. A number of other important possible target selenoproteins have been identified

  15. Mercury pollution in Wuchuan mercury mining area, Guizhou, Southwestern China: the impacts from large scale and artisanal mercury mining.

    Science.gov (United States)

    Li, Ping; Feng, Xinbin; Qiu, Guangle; Shang, Lihai; Wang, Shaofeng

    2012-07-01

    To evaluate the environmental impacts from large scale mercury mining (LSMM) and artisanal mercury mining (AMM), total mercury (THg) and methyl mercury (MeHg) were determined in mine waste, ambient air, stream water and soil samples collected from Wuchuan mercury (Hg) mining area, Guizhou, Southwestern China. Mine wastes from both LSMM and AMM contained high THg concentrations, which are important Hg contamination sources to the local environment. Total gaseous mercury (TGM) concentrations in the ambient air near AMM furnaces were highly elevated, which indicated that AMM retorting is a major source of Hg emission. THg concentrations in the stream water varied from 43 to 2100 ng/L, where the elevated values were mainly found in the vicinity of AMM and mine waste heaps of LSMM. Surface soils were seriously contaminated with Hg, and land using types and organic matter played an important role in accumulation and transportation of Hg in soil. The results indicated heavy Hg contaminations in the study area, which were resulted from both LSMM and AMM. The areas impacted by LSMM were concentrated in the historical mining and smelting facilities, while Hg pollution resulted from AMM can be distributed anywhere in the Hg mining area. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Mercury content in electrum from artisanal mining site of Mongolia

    Energy Technology Data Exchange (ETDEWEB)

    Murao, Satoshi [Geological Survey of Japan, AIST, Higashi 1-1-1, No. 7, Tsukuba 305-8567 (Japan)]. E-mail: s.murao@aist.go.jp; Naito, Kazuki [Geological Survey of Japan, AIST, Higashi 1-1-1, No. 7, Tsukuba 305-8567 (Japan); Dejidmaa, Gunchin [Geological Information Center, Mineral and Petroleum Resources Authority of Mongolia, State Building No. 5, Ulaanbaatar (Mongolia); Sie, Soey H. [CSIRO, P.O. Box 136, North Ryde, NSW 1670 (Australia)

    2006-08-15

    In Mongolia, artisanal gold mining, modern gold rush, in which people use mercury to extract gold, is being proliferated rapidly and the mercury contamination of mining site is becoming a serious social issue. For the risk assessment of mercury, it is necessary to understand how much mercury is introduced to the environment from what kind of materials during mining activity. It is already known that major contribution of the contamination comes from mercury that was bought at shops and brought to mining sites by miners. However, no information is available on how much mercury is removed from electrum (natural gold grain) to the environment. Since gold deposit is always accompanied by mercury anomaly, it is anticipated that electrum grains contain some amount of mercury of natural origin, and this mercury (primary mercury) contributes to some extent to the contamination. In order to clarify how much mercury is incorporated in electrum grains, micro-PIXE at CSIRO was used for grain-by-grain analysis. The result showed that electrum from study area contains mercury up to 8260 ppm. It is concluded that for the risk management of mercury contamination, release of natural mercury from electrum grains during smelting must not be ignored.

  17. Mercury content in electrum from artisanal mining site of Mongolia

    Science.gov (United States)

    Murao, Satoshi; Naito, Kazuki; Dejidmaa, Gunchin; Sie, Soey H.

    2006-08-01

    In Mongolia, artisanal gold mining, modern gold rush, in which people use mercury to extract gold, is being proliferated rapidly and the mercury contamination of mining site is becoming a serious social issue. For the risk assessment of mercury, it is necessary to understand how much mercury is introduced to the environment from what kind of materials during mining activity. It is already known that major contribution of the contamination comes from mercury that was bought at shops and brought to mining sites by miners. However, no information is available on how much mercury is removed from electrum (natural gold grain) to the environment. Since gold deposit is always accompanied by mercury anomaly, it is anticipated that electrum grains contain some amount of mercury of natural origin, and this mercury (primary mercury) contributes to some extent to the contamination. In order to clarify how much mercury is incorporated in electrum grains, micro-PIXE at CSIRO was used for grain-by-grain analysis. The result showed that electrum from study area contains mercury up to 8260 ppm. It is concluded that for the risk management of mercury contamination, release of natural mercury from electrum grains during smelting must not be ignored.

  18. Mercury content in electrum from artisanal mining site of Mongolia

    International Nuclear Information System (INIS)

    Murao, Satoshi; Naito, Kazuki; Dejidmaa, Gunchin; Sie, Soey H.

    2006-01-01

    In Mongolia, artisanal gold mining, modern gold rush, in which people use mercury to extract gold, is being proliferated rapidly and the mercury contamination of mining site is becoming a serious social issue. For the risk assessment of mercury, it is necessary to understand how much mercury is introduced to the environment from what kind of materials during mining activity. It is already known that major contribution of the contamination comes from mercury that was bought at shops and brought to mining sites by miners. However, no information is available on how much mercury is removed from electrum (natural gold grain) to the environment. Since gold deposit is always accompanied by mercury anomaly, it is anticipated that electrum grains contain some amount of mercury of natural origin, and this mercury (primary mercury) contributes to some extent to the contamination. In order to clarify how much mercury is incorporated in electrum grains, micro-PIXE at CSIRO was used for grain-by-grain analysis. The result showed that electrum from study area contains mercury up to 8260 ppm. It is concluded that for the risk management of mercury contamination, release of natural mercury from electrum grains during smelting must not be ignored

  19. Portable and Disposable Paper-Based Fluorescent Sensor for In Situ Gaseous Hydrogen Sulfide Determination in Near Real-Time.

    Science.gov (United States)

    Petruci, João Flávio da Silveira; Cardoso, Arnaldo Alves

    2016-12-06

    Hydrogen sulfide is found in many environments including sewage systems, petroleum extraction platforms, kraft paper mills, and exhaled breath, but its determination at ppb levels remains a challenge within the analytical chemistry field. Off-line methods for analysis of gaseous reduced sulfur compounds can suffer from a variety of biases associated with high reactivity, sorptive losses, and atmospheric oxidative reactions. Here, we present a portable, online, and disposable gas sensor platform for the in situ determination of gaseous hydrogen sulfide, employing a 470 nm light emitting diode (LED) and a microfiber optic USB spectrometer. A sensing layer was created by impregnating 2.5 μL (0.285 nmol) of fluorescein mercury acetate (FMA) onto the surface of a micropaper analytical device with dimensions of 5 × 5 mm, which was then positioned in the optical detection system. The quantitative determination of H 2 S was based on the quenching of fluorescence intensity after direct selective reaction between the gas and FMA. This approach enabled linear calibration within the range 17-67 ppb of H 2 S, with a limit of detection of 3 ppb. The response time of the sensor was within 60 s, and the repeatability was 6.5% (RSD). The sensor was employed to monitor H 2 S released from a mini-scale wastewater treatment tank in a research laboratory. The appropriate integration of optoelectronic and mechanical devices, including LED, photodiode, pumps, and electronic boards, can be used to produce simple, fully automated portable sensors for the in situ determination of H 2 S in a variety of environments.

  20. Uranium, thorium and REE partitioning into sulfide liquids at high pressure and high temperature: Implications for reduced, S-rich planetary bodies

    Science.gov (United States)

    Wohlers, A.; Wood, B. J.

    2017-12-01

    Based on models of the young solar nebula it is likely that the inner planets went through an early reduced phase of accretion with high metal/silicate ratio and low volatile element contents. Mercury is an existing example of a large planetary embryo with these characteristics but also with a very high S content. In order to investigate the geochemical evolution of Mercury-like bodies we experimentally determined the partitioning of lithophile elements (U, Th, Eu, Sm, Nd, Zr, La, Ce, Yb) between sulfide liquid, low-S metals and silicate melt at 1.5 GPa and 1400-2100˚C. Our results, when combined with those of Wohlers and Wood (2015) show that under highly reducing conditions (FeOsilicatemetal and FeO contents of the silicate may be understood in terms of exchange reactions: UO2 + 2FeS = 2FeO + US2silicate sulfide silicate sulfideHigh concentrations of FeSmetal and low FeO contents of the silicate melts drive the reaction to the right, yielding high US2 in the sulfide and high DU. A second effect which raises DU (and other lithophile D's) is the S content of the silicate melt. The latter increases rapidly at low FeO contents and reaches 11wt %. This greatly reduces the activity coefficient of FeO, displacing the reaction further to the right. At 1.5GPa and 1400˚C we obtain sulfide-silicate partitioning with DNd/DSm 1.4 and DTh 0.1DU. As temperature increases to 2100˚C, DNd/DSm declines to 1.0 and DTh/DU increases to 0.3. We estimated the effects of accreting a reduced sulfur-rich component (with FeS core) added to early Earth. The results at 1400˚C imply the possibility of a significant ( 11ppm) 142Nd anomaly in silicate Earth and the addition of >8 ppb U to the core, but require an unreasonably high Th/U of silicate Earth (4.54). Results at 2100˚C lead to a 142Nd anomaly of 0 but addition of such a reduced sulfur-rich body could add up to 10 ppb of U to the core, together with 21 ppb Th. This combination would generate 3 TW of the energy required for the