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Sample records for inorganic mercury determination

  1. Inorganic: the other mercury.

    PubMed

    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.

  2. Simultaneous determination of inorganic mercury and methylmercury compounds in natural waters.

    PubMed

    Logar, Martina; Horvat, Milena; Akagi, Hirokatsu; Pihlar, Boris

    2002-11-01

    The purpose of the present work was to develop a simple, rapid, sensitive and accurate method for the simultaneous determination of inorganic mercury (Hg(2+)) and monomethylmercury compounds (MeHg) in natural water samples at the pg L(-1) level. The method is based on the simultaneous extraction of MeHg and Hg(2+)dithizonates into an organic solvent (toluene) after acidification of about 300 mL of a water sample, followed by back extraction into an aqueous solution of Na(2)S, removal of H(2)S by purging with N(2), subsequent ethylation with sodium tetraethylborate, room temperature precollection on Tenax, isothermal gas chromatographic separation (GC), pyrolysis and cold vapour atomic fluorescence spectrometric detection (CV AFS) of mercury. The limit of detection calculated on the basis of three times the standard deviation of the blank was about 0.006 ng L(-1) for MeHg and 0.06 ng L(-1) for Hg(2+)when 300 mL of water was analysed. The repeatability of the results was about 5% for MeHg and 10% for Hg(2+). Recoveries were 90-110% for both species.

  3. Determination of inorganic and total mercury by vapor generation atomic absorption spectrometry using different temperatures of the measurement cell

    NASA Astrophysics Data System (ADS)

    Kaercher, Luiz Eduardo; Goldschmidt, Fabiane; Paniz, José Neri Gottfried; de Moraes Flores, Érico Marlon; Dressler, Valderi Luiz

    2005-06-01

    A simple and inexpensive laboratory-built flow injection vapor generation system coupled to atomic absorption spectrometry (FI-VG AAS) for inorganic and total mercury determination has been developed. It is based on the vapor generation of total mercury and a selective detection of Hg 2 + or total mercury by varying the temperature of the measurement cell. Only the inorganic mercury is measured when the quartz cell is at room temperature, and when the cell is heated to 650 °C or higher the total Hg concentration is measured. The organic Hg concentration in the sample is calculated from the difference between the total Hg and Hg 2 + concentrations. Parameters such as the type of acid (HCl or HNO 3) and its concentration, reductant (NaBH 4) concentration, carrier solution (HCl) flow rate, carrier gas flow rate, sample volume and quartz cell temperature, which influence FI-VG AAS system performance, were systematically investigated. The optimized conditions for Hg 2 + and total Hg determinations were: 1.0 mol l - 1 HCl as carrier solution, carrier flow rate of 3.5 ml min - 1 , 0.1% (m/v) NaBH 4, reductant flow rate of 1.0 ml min - 1 and carrier gas flow rate of 200 ml min - 1 . The relative standard deviation (RSD) is lower than 5.0% for a 1.0 μg l - 1 Hg solution and the limit of quantification (LOQ, 10 s) is 55 ng g - 1 . Certified samples of dogfish muscle (DORM-1 and DORM-2) and non-certified fish samples were analyzed, using a 6.0 mol l - 1 HCl solution for analyte extraction. The Hg 2 + and CH 3Hg + concentrations found were in agreement with certified ones.

  4. Simultaneous determination of inorganic mercury, methylmercury, and total mercury concentrations in cryogenic fresh-frozen and freeze-dried biological reference materials.

    PubMed

    Point, David; Davis, W Clay; Garcia Alonso, J Ignacio; Monperrus, Mathilde; Christopher, Steven J; Donard, Olivier F X; Becker, Paul R; Wise, Stephen A

    2007-10-01

    Two speciated isotope dilution (SID) approaches consisting of a single-spike (SS) method and a double-spike (DS) method including a reaction/transformation model for the correction of inadvertent transformations affecting mercury species were compared in terms of accuracy, method performance, and robustness for the simultaneous determination of methylmercury (MeHg), inorganic mercury (iHg), and total mercury (HgT) concentrations in five biological Standard Reference Materials (SRMs). The SRMs consisted of oyster and mussel tissue materials displaying different mercury species concentration levels and different textural/matrix properties including freeze-dried (FD) materials (SRMs 1566b, 2976, and 2977) and cryogenically prepared and stored fresh-frozen (FF) materials (SRMs 1974a, 1974b). Each sample was spiked with (201)iHg (Oak Ridge National Laboratory, ORNL) and Me(202)Hg (Institute for Reference Materials and Measurements. IRMM-670) solutions and analyzed using alkaline microwave digestion, ethylation, and gas chromatography inductively coupled plasma mass spectrometry (GC/ICP-MS). The results obtained by the SS-SID method suggested that FF and FD materials are not always commutable for the simultaneous determination of iHg, MeHg, and HgT, due to potential transformation reactions resulting probably from the methodology and/or from the textural/matrix properties of the materials. These transformations can occasionally significantly affect mercury species concentration results obtained by SS-SID, depending on the species investigated and the materials considered. The results obtained by the DS-SID method indicated that the two classes of materials were commutable. The simultaneous and corrected concentrations of iHg, MeHg, and HgT obtained by this technique were not found to be statistically different form the certified and reference concentration together with their expanded uncertainty budgets for the five SRMs investigated, exemplifying the robustness, the

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

    PubMed

    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.

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

    SciTech Connect

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

    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.

  7. Methylation of inorganic mercury in polar marine waters

    NASA Astrophysics Data System (ADS)

    Lehnherr, Igor; St. Louis, Vincent L.; Hintelmann, Holger; Kirk, Jane L.

    2011-05-01

    Monomethylmercury is a neurotoxin that accumulates in marine organisms, with serious implications for human health. The toxin is of particular concern to northern Inuit peoples, for example, whose traditional diets are composed primarily of marine mammals and fish. The ultimate source of monomethylmercury to marine organisms has remained uncertain, although various potential sources have been proposed, including export from coastal and deep-sea sediments and major river systems, atmospheric deposition and water-column production. Here, we report results from incubation experiments in which we added isotopically labelled inorganic mercury and monomethylmercury to seawater samples collected from a range of sites in the Canadian Arctic Archipelago. Monomethylmercury formed from the methylation of inorganic mercury in all samples. Demethylation of monomethylmercury was also observed in water from all sites. We determined steady-state concentrations of monomethylmercury in marine waters by incorporating the rate constants for monomethylmercury formation and degradation derived from these experiments into a numerical model. We estimate that the conversion of inorganic mercury to monomethylmercury in the water column accounts for around 47% (+/-62%, standard deviation) of the monomethylmercury present in polar marine waters, with site-to-site differences in inorganic mercury and monomethylmercury levels accounting for most of the variability. We suggest that water-column methylation of inorganic mercury is a significant source of monomethylmercury in pelagic marine food webs in the Arctic, and possibly in the world's oceans in general.

  8. Direct determination of methylmercury and inorganic mercury in biological materials by solid sampling-electrothermal vaporization-inductively coupled plasma-isotope dilution-mass spectrometry.

    PubMed

    Gelaude, I; Dams, R; Resano, M; Vanhaecke, F; Moens, L

    2002-08-01

    This paper reports on the use of solid sampling-electrothermal vaporization-inductively coupled plasma mass spectrometry (SS-EIV-ICPMS) for the direct and simultaneous determination of methylmercury and inorganic mercury in biological materials. The main advantage of this fast and sensitive method is that no sample preparation is required. In this way, the sample throughput can be considerably increased, problems of contamination and analyte losses are kept to a minimum and, even more important, the original chemical form of the different analyte species in the solid samples is preserved. To achieve this goal, a solid sample is inserted into a graphite furnace of the boat-in-tube type and is subsequently submitted to an appropriate temperature program, leading to the separate vaporization of methylmercury and inorganic mercury, which are transported into the ICP by means of an argon carrier gas. The separation was accomplished within 75 s. For the quantification of the two peaks, species-unspecific isotope dilution was used. For this purpose, a stable flow of argon loaded with gaseous Hg isotopically enriched in 200Hg was generated using a permeation tube that was constructed in-house. Its emission rate was determined by collecting the mercury released during a given time interval on a gold-coated silica absorber, after which the amount collected was released by heating of the absorber and determined by cold vapor atomic absorption spectrometry (CVAAS) and cold vapor atomic fluorescence spectrometry (CVAFS). A reference material from the Canadian National Research Council (NRC) (TORT-2) was used to assess the accuracy of the method. For the application of the method to samples with diverse mercury contents, the spike/sample ratio can be optimized by varying the emission rate of the permeation tube simply by adapting its temperature. To prove the feasibility of this approach, two reference materials (BCR 463 and DORM-2) with a methylmercury content more than 10

  9. Human exposure and health effects of inorganic and elemental mercury.

    PubMed

    Park, Jung-Duck; Zheng, Wei

    2012-11-01

    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.

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

    PubMed Central

    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

  11. The use of emulsions for the determination of methylmercury and inorganic mercury in fish-eggs oil by cold vapor generation in a flow injection system with atomic absorption spectrometric detection.

    PubMed

    Burguera, J L; Quintana, I A; Salager, J L; Burguera, M; Rondón, C; Carrero, P; Anton de Salager, R; Petit de Peña, Y

    1999-04-01

    An on-line time based injection system used in conjunction with cold vapor generation atomic absorption spectrometry and microwave-aided oxidation with potassium persulfate has been developed for the determination of the different mercury species in fish-eggs oil samples. A three-phase surfactant-oil-water emulsion produced an advantageous flow when a peristaltic pump was used to introduce the highly viscous sample into the system. The optimum proportion of the oil-water mixture ratio was 2:3 v/v with a Tween 20 surfactant concentration in the emulsion of 0.008% v/v. Inorganic mercury was determined after reduction with sodium borohydride while total mercury was determined after an oxidation step with persulfate prior to the reduction step to elemental mercury with the same reducing agent. The difference between total and inorganic mercury determined the organomercury content in samples. A linear calibration graph was obtained in the range 0.1-20 micrograms l-1 of Hg2+ by injecting 0.7 ml of samples. The detection limits based on 3 sigma of the blank signals were 0.11 and 0.12 microgram l-1 for total and inorganic mercury, respectively. The relative standard deviation of ten independent measurements were 2.8 and 2.2% for 10 micrograms l-1 and 8.8 and 9.0% for 0.1 microgram l-1 amounts of total and inorganic mercury, respectively. The recoveries of 0.3, 0.6 and 8 micrograms l-1 of inorganic and organic mercury added to fish-eggs oil samples ranged from 93.0 to 94.8% and from 100 to 106%, respectively. Good agreement with those values obtained for total mercury content in real samples by electrothermal atomic absorption spectrometry was also obtained, differences between mean values were < 7%. With the proposed procedure, 22 proteropterous catfish-eggs oil samples from the northwestern coast of Venezuela were measured; while the organic mercury lay in the range 2.0 and 3.3 micrograms l-1, inorganic mercury was not detected.

  12. Mercury

    MedlinePlus

    ... the lungs Medicine to remove mercury and heavy metals from the body INORGANIC MERCURY For inorganic mercury ... Baum CR. Mercury: Heavy metals and inorganic agents. In: Shannon MW, ... and Winchester's Clinical Management of Poisoning and Drug ...

  13. Intrarenal distribution of inorganic mercury and albumin after coadministration

    SciTech Connect

    Zalups, R.K. ); Barfuss, D.W. )

    1993-01-01

    The renal disposition and the intrarenal distribution of albumin and mercury were studied simultaneously in rats co-injected with a 0.5-[mu]mol/kg dose of albumin and a 0.25-[mu]mol/kg dose of inorganic mercury at 2, 5, 30, and 180 min after injection. These studies were carried out to test the hypothesis that one of the mechanisms involved in the renal tubular uptake of inorganic mercury is cotransport with albumin. By the end of the first 2 min after injection, the ratio of inorganic mercury to albumin in the renal cortex and outer strip of the outer medulla was approximately 2.6 and 1.6, respectively. Both the cortex and outer stripe contain segments of the proximal tubule, and it is these segments that have been shown to be principally involved in the renal tubular uptake of both albumin and inorganic mercury. The ration increased slightly in these two zones after 5 and 20 min after injection. These data demonstrate that there is a relatively close relationship in the renal content of inorganic mercury and albumin. However, the ratios are significantly greater than the ratio of inorganic mercury of albumin in the injection solution, which was 0.5. After 180 min following co-injection, the ratio increased to about 38 in the cortex and 15 in the outer stripe. This increase in the ratio is probably related to the metabolism of albumin. Based on the ratios of inorganic mercury to albumin in the renal cortex and outer stripe of the outer medulla, it appears that some proximal tubular uptake of inorganic mercury occurs by mechanisms other than endocytotic cotransport of inorganic mercury with albumin. However, since the ratios were small during the early times after injection, cotransport of inorganic mercury with albumin cannot be excluded as one of the mechanisms involved in the proximal tubular uptake of inorganic mercury. 32 refs., 12 figs., 4 tabs.

  14. Determination of total cadmium, lead, arsenic, mercury and inorganic arsenic in mushrooms: outcome of IMEP-116 and IMEP-39

    PubMed Central

    Cordeiro, F.; Llorente-Mirandes, T.; López-Sánchez, J.F.; Rubio, R.; Sánchez Agullo, A.; Raber, G.; Scharf, H.; Vélez, D.; Devesa, V.; Fiamegos, Y.; Emteborg, H.; Seghers, J.; Robouch, P.; de la Calle, M.B.

    2015-01-01

    The Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC), a Directorate General of the European Commission, operates the International Measurement Evaluation Program (IMEP). IMEP organises inter-laboratory comparisons in support of European Union policies. This paper presents the results of two proficiency tests (PTs): IMEP-116 and IMEP-39, organised for the determination of total Cd, Pb, As, Hg and inorganic As (iAs) in mushrooms. Participation in IMEP-116 was restricted to National Reference Laboratories (NRLs) officially appointed by national authorities in European Union member states. IMEP-39 was open to all other laboratories wishing to participate. Thirty-seven participants from 25 countries reported results in IMEP-116, and 62 laboratories from 36 countries reported for the IMEP-39 study. Both PTs were organised in support to Regulation (EC) No. 1881/2006, which sets the maximum levels for certain contaminants in food. The test item used in both PTs was a blend of mushrooms of the variety shiitake (Lentinula edodes). Five laboratories, with demonstrated measurement capability in the field, provided results to establish the assigned values (X ref). The standard uncertainties associated to the assigned values (u ref) were calculated by combining the uncertainty of the characterisation (u char) with a contribution for homogeneity (u bb) and for stability (u st), whilst u char was calculated following ISO 13528. Laboratory results were rated with z- and zeta (ζ)-scores in accordance with ISO 13528. The standard deviation for proficiency assessment, σ p, ranged from 10% to 20% depending on the analyte. The percentage of satisfactory z-scores ranged from 81% (iAs) to 97% (total Cd) in IMEP-116 and from 64% (iAs) to 84% (total Hg) in IMEP-39. PMID:25365736

  15. Cystine alters the renal and hepatic disposition of inorganic mercury and plasma thiol status

    SciTech Connect

    Zalups, Rudolfs K. . E-mail: zalups_rk@mercer.edu; Lash, Lawrence H.

    2006-07-01

    In the present study, we determined whether cystine can inhibit, under certain conditions, the renal tubular uptake of inorganic mercury in vivo. We co-injected (i.v.) cystine with a non-toxic dose of mercuric chloride to rats and then studied the disposition of inorganic mercury during the next 24 h. We also determined if pretreatment with cystine influences the disposition of administered inorganic mercury. Moreover, plasma thiol status was examined after the intravenous administration of cystine with or without mercuric chloride. During the initial hour after co-injection, the renal tubular uptake of mercuric ions was diminished significantly relative to that in control rats. The inhibitory effects of cystine were evident in both the renal cortex and outer stripe of the outer medulla. In contrast, the renal accumulation of mercury increased significantly between the 1st and 12th hour after co-treatment. Urinary excretion and fecal excretion of mercury were greatly elevated in the rats co-treated with cystine and mercuric chloride. Thus, when cystine and mercury are administered simultaneously, cystine can serve as an inhibitor of the renal tubular uptake of mercury during the initial hour after co-treatment. In rats pretreated with cystine, the renal uptake of inorganic mercury was enhanced significantly relative to that in rats not pretreated with cystine. This enhanced accumulation of inorganic mercury correlated with the increased circulating concentrations of the reduced cysteine and glutathione. Additionally, the present findings indicate that thiol status is an important determinant of renal and hepatic disposition, and urinary and fecal excretion, of inorganic mercury.

  16. Determination of trace inorganic mercury species in water samples by cloud point extraction and UV-vis spectrophotometry.

    PubMed

    Ulusoy, Halil Ibrahim

    2014-01-01

    A new micelle-mediated extraction method was developed for preconcentration of ultratrace Hg(II) ions prior to spectrophotometric determination. 2-(2'-Thiazolylazo)-p-cresol (TAC) and Ponpe 7.5 were used as the chelating agent and nonionic surfactant, respectively. Hg(II) ions form a hydrophobic complex with TAC in a micelle medium. The main factors affecting cloud point extraction efficiency, such as pH of the medium, concentrations of TAC and Ponpe 7.5, and equilibration temperature and time, were investigated in detail. An overall preconcentration factor of 33.3 was obtained upon preconcentration of a 50 mL sample. The LOD obtained under the optimal conditions was 0.86 microg/L, and the RSD for five replicate measurements of 100 microg/L Hg(II) was 3.12%. The method was successfully applied to the determination of Hg in environmental water samples.

  17. Methyl mercury, but not inorganic mercury, associated with higher blood pressure during pregnancy.

    PubMed

    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.

  18. Historical and other patterns of monomethyl and inorganic mercury in the Florida panther (Puma concolor coryi).

    PubMed

    Newman, J; Zillioux, E; Rich, E; Liang, L; Newman, C

    2005-01-01

    Since the late 1980s, elevated levels of mercury have been reported in the tissues of the Florida panther (Puma concolor coryi) from the Florida Everglades. The extent, degree, and length of time of mercury contamination in the Florida panther are unknown. The objective of this study was to determine the historical and other patterns of monomethyl and inorganic mercury in the Florida panther by analysis of mercury in panther hair from museum collections. In addition, this study evaluated the effects of preservation of skins on mercury concentrations in hair and the representativeness of museum collections for evaluating historical trends of contamination in the Florida panther. Hair from 42 Florida panther specimens collected from 1896 to 1995 was analyzed for both monomethyl and inorganic mercury. Monomethyl mercury (MMHg) and inorganic mercury (IHg) were found in all specimens. Monomethyl mercury in hair from untanned skins was significantly higher than MMHg in hair from tanned skins. For untanned specimens, the mean MMHg concentration in hair was 1.62 +/- 1.87 mug/g (range 0.11 to 6.68 mug/g, n = 16). Monomethyl mercury accounted for 88% of the total mercury in untanned Florida panther hair. No sexual or geographical differences were found. Although MMHg is generally stable in hair, the tanning process appears to reduce the amount of MMHg in hair. In addition, exogenous IHg contamination of the panther hair was found in museum specimens, especially in older specimens. The implication of these and other factors in interpreting results of museum studies is discussed. The presence of MMHg in panther hair since the 1890s indicates long-term and widespread exposure of the Florida panther to mercury. Levels of MMHg are significantly greater in the 1990s than the 1890s. When combined with field studies of mercury in the Florida panther, considerable individual variability is observed, reflecting short-term changes in exposure of individual panthers to mercury. Although

  19. Determination of mercurous chloride and total mercury in mercury ores

    USGS Publications Warehouse

    Fahey, J.J.

    1937-01-01

    A method for the determination of mercurous chloride and total mercury on the same sample is described. The mercury minerals are volatilized in a glass tube and brought into intimate contact with granulated sodium carbonate. The chlorine is fixed as sodium chloride, determined with silver nitrate, and computed to mercurous chloride. The mercury is collected on a previously weighed gold coil and weighed.

  20. Thorough removal of inorganic and organic mercury from aqueous solutions by adsorption on Lemna minor powder.

    PubMed

    Li, Shun-Xing; Zheng, Feng-Ying; Yang, Huang; Ni, Jian-Cong

    2011-02-15

    The adsorption ability of duckweed (Lemna minor) powders for removing inorganic and organic mercury (methyl and ethyl mercury) has been studied using cold vapour atomic absorption spectrometry. The optimal adsorption conditions were: (a) the pH value of the solution 7.0 for inorganic and ethyl mercury, 9.0 for methyl mercury, and (b) equilibrium adsorption time 10, 20, and 40 min for inorganic mercury, methyl mercury, and ethyl mercury, respectively. After adsorption by L. minor powder for 40 min, when the initial concentrations of inorganic and organic mercury were under 12.0 μg L(-1) and 50.0 μg L(-1), respectively, the residual concentrations of mercury could meet the criterion of drinking water (1.0 μg L(-1)) and the permitted discharge limit of wastewater (10.0 μg L(-1)) set by China and USEPA, respectively. Thorough removal of both inorganic and organic mercury from aqueous solutions was reported for the first time. The significant adsorption sites were C-O-P and phosphate groups by the surface electrostatic interactions with aqueous inorganic and organic mercury cations, and then the selective adsorption was resulted from the strong chelating interaction between amine groups and mercury on the surface of L. minor cells.

  1. Accumulation properties of inorganic mercury and organic mercury in the red-crowned crane Grus japonensis in east Hokkaido, Japan.

    PubMed

    Teraoka, Hiroki; Okamoto, Erika; Kudo, Moe; Nakayama, Shouta M M; Ikenaka, Yoshinori; Ishizuka, Mayumi; Endo, Tetsuya; Kitazawa, Takio; Hiraga, Takeo

    2015-12-01

    The red-crowned (Japanese) crane Grus japonensis is native to east Hokkaido, Japan, in contrast to the East Asia mainland. Previously, we reported that red-crowned cranes in Hokkaido were highly contaminated with mercury in the 1990s and that the contamination rapidly decreased to a moderate level in the 2000s. In the present study, we determined levels of organic mercury (O-Hg) in the liver and kidney of cranes in east Hokkaido in comparison with levels of total mercury (T-Hg). T-Hg levels in the kidneys were higher than those in the livers in adults but not in subadults and juveniles; however, the reverse was the case for O-Hg even for adults. The ratio of O-Hg to T-Hg in both the liver and kidney decreased as T-Hg increased in the three developmental stages. While the ratios of O-Hg to T-Hg in the liver and kidney of adults were significantly lower than those of juveniles, the ratios were similar for adults and juveniles in a lower range of T-Hg. The ratio of selenium (Se) to T-Hg decreased as T-Hg increased in both the liver and kidney, irrespective of stages. Mercury burdens in feathers were about 59% and 67% of the total body burdens for juveniles and adults, respectively. Furthermore, ratios of carbon and nitrogen stable isotopes to T-Hg varied greatly, with no relation to mercury level in the liver. The results suggest slow accumulation of inorganic mercury in the kidney of red-crowned cranes in east Hokkaido, Japan.

  2. Prenatal and early postnatal intoxication by inorganic mercury resulting from the maternal use of mercury containing soap.

    PubMed

    Lauwerys, R; Bonnier, C; Evrard, P; Gennart, J P; Bernard, A

    1987-05-01

    A case of slight renal tubular dysfunction associated with cataract and anaemia was diagnosed in a 3-month-old black boy in whom high levels of mercury were found in blood and urine. Several arguments suggest that the renal, ocular and haematological defects may have resulted from exposure to mercury during foetal life and the 1-month lactation period due to the extensive use of inorganic mercury containing cosmetics by the mother.

  3. Solid Phase Extraction of Inorganic Mercury Using 5-Phenylazo-8-hydroxyquinoline and Determination by Cold Vapor Atomic Fluorescence Spectroscopy in Natural Water Samples

    PubMed Central

    Daye, Mirna; Halwani, Jalal; Hamzeh, Mariam

    2013-01-01

    8-Hydroxyquinoline (8-HQ) was chosen as a powerful ligand for Hg solid phase extraction. Among several chelating resins based on 8-HQ, 5-phenylazo-8-hydroxyquinoline (5Ph8HQ) is used for mercury extraction in which the adsorption dynamics were fully studied. It has been shown that Hg(II) is totally absorbed by 5Ph8HQ within the first 30 minutes of contact time with t1/2 5 minutes, following Langmuir adsorption model. At pH 4, the affinity of mercury is unchallenged by other metals except, for Cu(II), which have shown higher Kd value. With these latter characteristics, 5Ph8HQ was examined for the preconcentration of trace levels of Hg(II). The developed method showed quantitative recoveries of Hg(II) with LOD = 0.21 pg mL−1 and RSD = 3–6% using cold vapor atomic fluorescence spectroscopy (CV-AFS) with a preconcentration factor greater than 250. PMID:24459417

  4. Determination of mercury in soil samples

    SciTech Connect

    Ayala, N.L.; Barber, T.E.; Turner, R.R.; Foust, D.F.

    1997-12-31

    A field screening method for the determination of mercury in soil samples using an iodine-based extractant was developed. The mercury compounds present in the soil samples were converted to tetraiodo mercurate (HgI{sub 4}{sup -2}), and then reduce to elemental mercury using reducing sugars. The mercury vapor present in the headspace of the sample was determined using a field portable mercury analyzer (Arizona Instruments Inc., Phoenix, Arizona). The soil samples were also analyzed using EPA method 7471, and a field method developed at Oak Ridge National Laboratory (ORNL). The results obtained using the iodine based extractant and sugar reduction compared very favorably with the other two methods employed.

  5. Multidrug efflux transporters limit accumulation of inorganic, but not organic, mercury in sea urchin embryos.

    PubMed

    Bosnjak, Ivana; Uhlinger, Kevin R; Heim, Wesley; Smital, Tvrtko; Franekić-Colić, Jasna; Coale, Kenneth; Epel, David; Hamdoun, Amro

    2009-11-01

    Mercuric compounds are persistent global pollutants that accumulate in marine organisms and in humans who consume them. While the chemical cycles and speciation of mercury in the oceans are relatively well described, the cellular mechanisms that govern which forms of mercury accumulate in cells and why they persist are less understood. In this study we examined the role of multidrug efflux transport in the differential accumulation of inorganic (HgCl(2)) and organic (CH(3)HgCl) mercury in sea urchin (Strongylocentrotus purpuratus) embryos. We found that inhibition of MRP/ABCC-type transporters increases intracellular accumulation of inorganic mercury but had no effect on accumulation of organic mercury. Similarly, pharmacological inhibition of metal conjugating enzymes by ligands GST/GSH significantly increases this antimitotic potency of inorganic mercury, but had no effect on the potency of organic mercury. Our results point to MRP-mediated elimination of inorganic mercury conjugates as a cellular basis for differences in the accumulation and potency of the two major forms of mercury found in marine environments.

  6. The retention time of inorganic mercury in the brain — A systematic review of the evidence

    SciTech Connect

    Rooney, James P.K.

    2014-02-01

    Reports from human case studies indicate a half-life for inorganic mercury in the brain in the order of years—contradicting older radioisotope studies that estimated half-lives in the order of weeks to months in duration. This study systematically reviews available evidence on the retention time of inorganic mercury in humans and primates to better understand this conflicting evidence. A broad search strategy was used to capture 16,539 abstracts on the Pubmed database. Abstracts were screened to include only study types containing relevant information. 131 studies of interest were identified. Only 1 primate study made a numeric estimate for the half-life of inorganic mercury (227–540 days). Eighteen human mercury poisoning cases were followed up long term including autopsy. Brain inorganic mercury concentrations at death were consistent with a half-life of several years or longer. 5 radionucleotide studies were found, one of which estimated head half-life (21 days). This estimate has sometimes been misinterpreted to be equivalent to brain half-life—which ignores several confounding factors including limited radioactive half-life and radioactive decay from surrounding tissues including circulating blood. No autopsy cohort study estimated a half-life for inorganic mercury, although some noted bioaccumulation of brain mercury with age. Modelling studies provided some extreme estimates (69 days vs 22 years). Estimates from modelling studies appear sensitive to model assumptions, however predications based on a long half-life (27.4 years) are consistent with autopsy findings. In summary, shorter estimates of half-life are not supported by evidence from animal studies, human case studies, or modelling studies based on appropriate assumptions. Evidence from such studies point to a half-life of inorganic mercury in human brains of several years to several decades. This finding carries important implications for pharmcokinetic modelling of mercury and potentially for

  7. Essential Indicators Identifying Chronic Inorganic Mercury Intoxication: Pooled Analysis across Multiple Cross-Sectional Studies

    PubMed Central

    Doering, Stefan

    2016-01-01

    Background The continuous exposure to inorganic mercury vapour in artisanal small-scale gold mining (ASGM) areas leads to chronic health problems. It is therefore essential to have a quick, but reliable risk assessing tool to diagnose chronic inorganic mercury intoxication. This study re-evaluates the state-of-the-art toolkit to diagnose chronic inorganic mercury intoxication by analysing data from multiple pooled cross-sectional studies. The primary research question aims to reduce the currently used set of indicators without affecting essentially the capability to diagnose chronic inorganic mercury intoxication. In addition, a sensitivity analysis is performed on established biomonitoring exposure limits for mercury in blood, hair, urine and urine adjusted by creatinine, where the biomonitoring exposure limits are compared to thresholds most associated with chronic inorganic mercury intoxication in artisanal small-scale gold mining. Methods Health data from miners and community members in Indonesia, Tanzania and Zimbabwe were obtained as part of the Global Mercury Project and pooled into one dataset together with their biomarkers mercury in urine, blood and hair. The individual prognostic impact of the indicators on the diagnosis of mercury intoxication is quantified using logistic regression models. The selection is performed by a stepwise forward/backward selection. Different models are compared based on the Bayesian information criterion (BIC) and Cohen`s kappa is used to evaluate the level of agreement between the diagnosis of mercury intoxication based on the currently used set of indicators and the result based on our reduced set of indicators. The sensitivity analysis of biomarker exposure limits of mercury is based on a sequence of chi square tests. Results The variable selection in logistic regression reduced the number of medical indicators from thirteen to ten in addition to the biomarkers. The estimated level of agreement using ten of thirteen medical

  8. Induction by mercury compounds of metallothioneins in mouse tissues: inorganic mercury accumulation is not a dominant factor for metallothionein induction in the liver.

    PubMed

    Yasutake, Akira; Nakamura, Masaaki

    2011-06-01

    Among the naturally occurring three mercury species, metallic mercury (Hg(0)), inorganic mercury (Hg(II)) and methylmercury (MeHg), Hg(II) is well documented to induce metallothionein (MT) in tissues of injected animals. Although Hg(0) and MeHg are considered to be inert in terms of directly inducing MT, MT can be induced by them after in vivo conversion to Hg(II) in an animal body. In the present study we examined accumulations of inorganic mercury and MT inductions in mouse tissues (brain, liver and kidney) up to 72 hr after treatment by one of three mercury compounds of sub-lethal doses. Exposure to mercury compounds caused significant mercury accumulations in mouse tissues examined, except for the Hg(II)-treated mouse brain. Although MeHg caused the highest total mercury accumulation in all tissues among mercury compounds, the rates of inorganic mercury were less than 10% through the experimental period. MT inductions that depended on the inorganic mercury accumulation were observed in kidney and brain. However, MT induction in the liver could not be accounted for by the inorganic mercury accumulation, but by plasma IL6 levels, marked elevation of which was observed in Hg(II) or MeHg-treated mouse. The present study demonstrated that MT was induced in mouse tissues after each of three mercury compounds, Hg(0), Hg(II) and MeHg, but the induction processes were different among tissues. The induction would occur directly through accumulation of inorganic mercury in brain and kidney, whereas the hepatic MT might be induced secondarily through mercury-induced elevation in the plasma cytokines, rather than through mercury accumulation in the tissue.

  9. Comparative effects of chelating agents on distribution, excretion, and renal toxicity of inorganic mercury in rats

    SciTech Connect

    Kojima, S.; Shimada, H.; Kiyozumi, M. )

    1989-06-01

    The effects of three chelating agents, sodium N-benzyl-D-glucamine dithiocarbamate(NBG-DTC), 2,3-dimercaptopropanol(BAL), and D-penicillamine(D-PEN), on the distribution, excretion, and renal toxicity of inorganic mercury were compared in rats exposed to HgCl2. Rats were injected i.p. with 203HgCl2 (300 micrograms of Hg and 2 microCi of 203Hg/kg) and 30 min or 24 h later they were injected with a chelating agent (a quarter of an LD50). The injection of the chelating agents significantly enhanced the biliary and urinary excretions of mercury. BAL was the most effective for removal of mercury from the body at 30 min after mercury treatment. The extent of enhancing effect of the chelating agents for removal of mercury at 24 h after mercury was in the order NBG-DTC = BAL greater than D-PEN. The injection of BAL at 24 h after mercury treatment caused the redistribution of mercury to the heart and lung. NBG-DTC did not result in the redistribution of mercury to the heart, lung, and brain. Urinary excretion of protein and AST significantly increased 24-48 h after mercury treatment and decreased to the control values 72 h after mercury. The injection of the chelating agents at 30 min after mercury treatment significantly decreased the urinary excretion of protein and AST. In rats pretreated with mercury 24 h earlier, the chelating agents significantly decreased the urinary protein at 48 h after mercury treatment, but did not decrease the urinary AST. The results of this study indicate that the chelating agents are effective in removing mercury from the body, resulting in the protective effect against the mercury-induced renal damage.

  10. Luminal and basolateral mechanisms involved in the renal tubular uptake of inorganic mercury

    SciTech Connect

    Zalups, R.K.; Minor, K.H.

    1995-09-01

    The present study provides evidence for the existence of both a luminal and a basolateral mechanism involved in the renal tubular uptake of inorganic mercury. The researchers compared the disposition of inorganic mercury in groups of surgical control rats, rats that underwent a unilateral ureteral ligation, and rats that underwent a bilateral ureteral ligation that were pretreated with either normal saline or a 7.5 mmol/kg intravenous dose of PAH 5 min prior to receiving a nontoxic 0.5-{mu}mol/kg intravenous dose of mercuric chloride. The {open_quotes}stop-flow{close_quotes} conditions induced by either unilateral or bilateral ureteral ligation caused a significant reduction in the uptake and content of mercury in the kidneys (whose ureter was ligated) both at 1 h and 24 h after the intravenous injection of the nontoxic dose of mercuric chloride. This decreased renal uptake of mercury was due specifically to decreased uptake of mercury in the renal cortex and outer stripe of the outer medulla. The amount of mercury has not taken up during ureteral ligation represents the portion of mercury that is presumably taken up by a luminal mechanism. Pretreatment with PAH also caused a significant reduction in the renal uptake of mercury in the cortex and outer stripe of the outer medulla. When either unilateral or bilateral ureteral ligation was combined with PAH pretreatment, an additive inhibitory effect occurred with respect to the renal uptake of mercury. In fact, the renal uptake of mercury was reduced by approximately 85% at 1 h after the injection of mercuric chloride. Since the luminal uptake of mercury was blocked by ureteral ligation, the effect of PAH on the renal uptake of mercury must have occurred at the basolateral membrane. Two distinct mechanisms are involved in mercury uptake, with one mechanism located on the luminal membrane and another located on the basolateral membrane. 22 refs., 11 figs., 2 tabs.

  11. Catalysis-reduction strategy for sensing inorganic and organic mercury based on gold nanoparticles.

    PubMed

    Li, Xiaokun; Zhang, Youlin; Chang, Yulei; Xue, Bin; Kong, Xianggui; Chen, Wei

    2017-06-15

    In view of the high biotoxicity and trace concentration of mercury (Hg) in environmental water, developing simple, ultra-sensitive and highly selective method capable of simultaneous determination of various Hg species has attracted wide attention. Here, we present a novel catalysis-reduction strategy for sensing inorganic and organic mercury in aqueous solution through the cooperative effect of AuNP-catalyzed properties and the formation of gold amalgam. For the first time, a new AuNP-catalyzed-organic reaction has been discovered and directly used for sensing Hg(2+), Hg2(2+) and CH3Hg(+) according to the change of the amount of the catalytic product induced by the deposition of Hg atoms on the surface of AuNPs. The detection limit of Hg species is 5.0pM (1 ppt), which is 3 orders of magnitude lower than the U.S. Environmental Protection Agency (EPA) limit value of Hg for drinking water (2 ppb). The high selectivity can be exceptionally achieved by the specific formation of gold amalgam. Moreover, the application for detecting tap water samples further demonstrates that this AuNP-based assay can be an excellent method used for sensing mercury at very low content in the environment.

  12. Transformations of inorganic mercury by Candida albicans and Saccharomyces cerevisiae

    SciTech Connect

    Yannai, S.; Berdicevsky, I.; Duek, L. )

    1991-01-01

    Saccharomyces cerevisiae and Candida albicans were incubated with 0.25, 0.5, or 0.75 {mu}g of Hg (as HgCl{sub 2}) per ml of Nelson's medium in the presence of trace amounts of oxygen at 28{degree}C for 12 days. Two control media were used, one without added Hg and one without yeast inoculum. Yeast cell growth was estimated after 1, 2, 3, and 8 days of incubation. The contents of organomercury in the system and of elemental mercury released from the media and collected in traps were determined at the end of the experiments. The results were as follows: (1) C. albicans was the more mercury-resistant species, but both yeast species failed to grown in the media containing 0.75 {mu}g of Hg per ml.; (2) The amounts of organomercury produced by the two species were proportional to the amount of HgCl{sub 2} added to the medium. In all cases C. albicans produced considerably larger amounts of methylmercury than S. cerevisiae; (3) The amounts of elemental Hg produced were inversely proportional to the HgCl{sub 2} level added in the case of S. cerevisiae but were all similar in the case of C. albicans;and (4) Neither organomercury nor elemental Hg was produced in any of the control media.

  13. Docosahexaenoic acid counteracts attenuation of CD95-induced cell death by inorganic mercury

    SciTech Connect

    Gill, Randall; Lanni, Lydia; Jen, K.-L. Catherine; McCabe, Michael J.; Rosenspire, Allen

    2015-01-01

    In the United States the principal environmental exposure to mercury is through dietary consumption of sea food. Although the mechanism by which low levels of mercury affect the nervous system is not well established, epidemiological studies suggest that low level exposure of pregnant women to dietary mercury can adversely impact cognitive development in their children, but that Docosahexaenoic acid (DHA), the most prominent n-polyunsaturated fatty acid (n-PUFA) present in fish may counteract negative effects of mercury on the nervous system. Aside from effects on the nervous system, epidemiological and animal studies have also suggested that low level mercury exposure may be a risk factor for autoimmune disease. However unlike the nervous system where a mechanism linking mercury to impaired cognitive development remains elusive, we have previously suggested a potential mechanism linking low level mercury exposures to immune system dysfunction and autoimmunity. In the immune system it is well established that disruption of CD95 mediated apoptosis leads to autoimmune disease. We have previously shown in vitro as well as in vivo that in lymphocytes burdened with low levels of mercury, CD95 mediated cell death is impaired. In this report we now show that DHA counteracts the negative effect of mercury on CD95 signaling in T lymphocytes. T cells which have been pre-exposed to DHA are able to cleave pro-caspase 3 and efficiently signal programmed cell death through the CD95 signaling pathway, whether or not they are burdened with low levels of mercury. Thus DHA may lower the risk of autoimmune disease after low level mercury exposures. - Highlights: • Inorganic mercury (Hg{sup 2+}) interferes with CD95 mediated cell death in Jurkat T cells • DHA restores the ability of CD95 to signal cell death in Hg{sup 2+} intoxicated T cells • The restoration of CD95 mediated cell death by DHA is correlated with increased activation of Caspase 3.

  14. Trophic transfer efficiency of methylmercury and inorganic mercury to lake trout Salvelinus namaycush from its prey

    USGS Publications Warehouse

    Madenijian, C.P.; David, S.R.; Krabbenhoft, D.P.

    2012-01-01

    Based on a laboratory experiment, we estimated the net trophic transfer efficiency of methylmercury to lake trout Salvelinus namaycush from its prey to be equal to 76.6 %. Under the assumption that gross trophic transfer efficiency of methylmercury to lake trout from its prey was equal to 80 %, we estimated that the rate at which lake trout eliminated methylmercury was 0.000244 day−1. Our laboratory estimate of methylmercury elimination rate was 5.5 times lower than the value predicted by a published regression equation developed from estimates of methylmercury elimination rates for fish available from the literature. Thus, our results, in conjunction with other recent findings, suggested that methylmercury elimination rates for fish have been overestimated in previous studies. In addition, based on our laboratory experiment, we estimated that the net trophic transfer efficiency of inorganic mercury to lake trout from its prey was 63.5 %. The lower net trophic transfer efficiency for inorganic mercury compared with that for methylmercury was partly attributable to the greater elimination rate for inorganic mercury. We also found that the efficiency with which lake trout retained either methylmercury or inorganic mercury from their food did not appear to be significantly affected by the degree of their swimming activity.

  15. Isotopic fractionation during the uptake and elimination of inorganic mercury by a marine fish.

    PubMed

    Xu, Xiaoyu; Wang, Wen-Xiong

    2015-11-01

    This study investigated the mass dependent (MDF) and independent fractionation (MIF) of stable mercury isotopes in fish during the uptake and elimination of inorganic species. Mercury accumulation during the exposure led to re-equilibration of organ isotopic compositions with the external sources, and elimination terminated the equilibrating with isotope ratios moving back to the original values. Generally, the isotopic behaviors corresponded to the changes of Hg accumulation in the muscle and liver, causing by the internal transportation, organ redistribution, and mixing of different sources. A small degree of MDF caused by biotransformation of Hg in the liver was documented during the elimination, whereas MIF was not observed. The absence of MIF during geochemical and metabolic processes suggested that mercury isotopes can be used as source tracers. Additionally, fish liver is a more responsive organ than muscle to track Hg source when it is mainly composed of inorganic species.

  16. Maternal transfer of inorganic mercury and methylmercury in aquatic and terrestrial arthropods.

    PubMed

    Saxton, Heidi J; Goodman, James R; Collins, Jeffrey N; Black, Frank J

    2013-11-01

    The transfer of mercury from females to their offspring plays an important role in mercury accumulation and toxicity during early development. To quantify the transfer of inorganic mercury and methylmercury from female arthropods to their eggs, the authors collected and analyzed brine shrimp (Artemia franciscana), wolf spiders (Alopecosa spp.), and their attached eggs from aquatic and terrestrial ecosystems at the Great Salt Lake, Utah, USA. Essentially all of the mercury in both the female brine shrimp and their eggs was methylmercury (94 ± 17% and 90 ± 21%, respectively). The brine shrimp eggs had methylmercury concentrations that were 84 ± 2% lower than in the females, reflecting the fact that females transferred 45 ± 4% of their total body mass but only 11 ± 3% of their methylmercury burden to their eggs. As a result of this sequestration, the concentration of methylmercury in the female brine shrimp increased by 62 ± 8% during egg formation. The percentage of the total mercury that was methylmercury in female wolf spiders (77 ± 21%) was similar to that in their egg masses (81 ± 19%), indicating similar maternal transfer efficiencies for inorganic mercury and methylmercury in these invertebrates. The concentration of inorganic mercury and methylmercury in the female spiders was the same as in their eggs. These arachnids transferred 48 ± 9% of their total body mass, 55 ± 13% of their inorganic mercury, and 50 ± 9% of their methylmercury to their egg masses. Thus, female wolf spiders do not have the ability to reduce the transfer of methylmercury to their eggs, nor does this process represent an important pathway for the depuration of mercury. The present study demonstrates that although some arthropods have mechanisms to minimize the transfer of methylmercury to their eggs and reduce the potential for mercury toxicity during early development, other arthropods do not.

  17. Uptake dynamics of inorganic mercury and methylmercury by the earthworm Pheretima guillemi.

    PubMed

    Dang, Fei; Zhao, Jie; Zhou, Dongmei

    2016-02-01

    Mercury uptake dynamics in the earthworm Pheretima guillemi, including the dissolved uptake rate constant (ku) from pore-water and assimilation efficiencies (AEs) from mercury-contaminated soil, was quantified in this study. Dissolved uptake rate constants were 0.087 and 0.553 L g(-1) d(-1) for inorganic mercury (IHg) and methylmercury (MeHg), respectively. Assimilation efficiency of IHg in field-contaminated soil was 7.2%, lower than 15.4% of spiked soil. In contrast, MeHg exhibited comparable AEs for both field-contaminated and spiked soil (82.4-87.2%). Within the framework of biodynamic model, we further modelled the exposure pathways (dissolved exposure vs soil ingestion) to source the accumulated mercury in Pheretima guillemi. The model showed that the relative importance of soil ingestion to mercury bioaccumulation depended largely on mercury partitioning coefficients (K(d)), and was also influenced by soil ingestion rate of earthworms. In the examined field-contaminated soil, almost (>99%) accumulated IHg and MeHg was predicted to derive from soil ingestion. Therefore, soil ingestion should be carefully considered when assessing mercury exposure risk to earthworms.

  18. DIVALENT INORGANIC REACTIVE GASEOUS MERCURY EMISSIONS FROM A MERCURY CELL CHLOR-ALKALI PLANT AND ITS IMPACT ON NEAR FIELD ATMOSPHERIC DRY DEPOSITION

    EPA Science Inventory

    The emission of inorganic divalent reactive gaseous mercury (RGM) from a mercury cell chlor-alkali plant (MCCAP) cell building and the impact on near field (100 km) dry deposition was investigated as part of a larger collaborative study between EPA, University of Michigan, Oak ...

  19. Mercury in the dorsal root ganglia of rats treated with inorganic or organic mercury

    SciTech Connect

    Schioenning, J.D.; Moeller-Madsen, B.; Danscher, G. )

    1991-10-01

    Autometallographic silver amplification has been used to demonstrate the localization of mercury deposits in rat dorsal root ganglia after repeated intraperitoneal injections of mercuric chloride or methylmercuric chloride. The silver-enhanced mercury deposits were demonstrated with the light and electron microscope. The degree of intracellular staining of the individual cells depended on the mercury compound and total dosage. Ganglion cells (types A and B) and macrophages were found to accumulate mercury after a total dosage of 400 {mu}g HgCl{sub 2}. After 600 {mu}g HgCl{sub 2}, satellite cells, endothelial cells and fibroblasts were additionally found to contain mercury deposits. Treatment with 6,000 {mu}g CH{sub 3}HgCl caused faint staining of type A and B ganglion cells and fibroblasts. Macrophages, however, were the most heavily stained cells after treatment with CH{sub 3}HgCl. Ultrastructurally, mercury was exclusively located in lysosomes. This was irrespective of the cell type and mercury compound used for treatment.

  20. Phase transfer membrane supported liquid-liquid-liquid microextraction combined with large volume sample injection capillary electrophoresis-ultraviolet detection for the speciation of inorganic and organic mercury.

    PubMed

    Li, Pingjing; Zhang, Xing; Hu, Bin

    2011-12-30

    In this paper, a novel sample pretreatment technique termed phase transfer based liquid-liquid-liquid microextraction (PT-LLLME) was proposed for the simultaneous extraction of inorganic and organic mercury species. In PT-LLLME, an intermediate solvent (acetonitrile) was added into the donor phase to improve the contacting between target mercury species and complexing reagent. Meanwhile, a membrane supported (MS)-LLLME unit was designed to realize the PT-LLLME procedure. By using nylon membrane as supporting carrier, larger than 50 μL of acceptor solution could be hung up. Following PT/MS-LLLME, the acceptor solutions were directly analyzed by large volume sample stacking capillary electrophoresis/ultraviolet detection (LVSS-CE/UV). Accordingly, a new method of PT/MS-LLLME combined with LVSS-CE/UV was developed for the simultaneous speciation of inorganic and organic mercury species. Parameters affecting the extraction efficiency of PT/MS-LLLME were investigated in details. Under the optimized conditions, enrichment factors (EFs) ranging from 160- to 478-fold were obtained for the extraction of target mercury species by PT/MS-LLLME. By combining PT/MS-LLLME with LVSS-CE/UV, EFs were magnified up to 12,138-fold and the limits of detection (at a signal-to-noise ratio of 3) were at sub ppb level. The established approach of PT/MS-LLLME-LVSS-CE/UV was successfully applied to simultaneous determination of inorganic and organic mercury species in biological samples and environmental water samples.

  1. Long-Term Stability of Inorganic, Methyl and Ethyl Mercury in Whole Blood: Effects of Storage Temperature and Time

    PubMed Central

    Sommer, Yuliya L.; Ward, Cynthia D.; Pan, Yi; Caldwell, Kathleen L.; Jones, Robert L.

    2016-01-01

    In this study, we evaluated the effect of temperature on the long-term stability of three mercury species in bovine blood. We used inductively coupled plasma mass spectrometry (ICP-MS) analysis to determine the concentrations of inorganic (iHg), methyl (MeHg) and ethyl (EtHg) mercury species in two blood pools stored at temperatures of −70, −20, 4, 23°C (room temperature) and 37°C. Over the course of a year, we analyzed aliquots of pooled specimens at time intervals of 1, 2, 4 and 6 weeks and 2, 4, 6, 8, 10 and 12 months. We applied a fixed-effects linear model, step-down pairwise comparison and coefficient of variation statistical analysis to examine the temperature and time effects on changes in mercury species concentrations. We observed several instances of statistically significant differences in mercury species concentrations between different temperatures and time points; however, with considerations of experimental factors (such as instrumental drift and sample preparation procedures), not all differences were scientifically important. We concluded that iHg, MeHg and EtHg species in bovine whole blood were stable at −70, −20, 4 and 23°C for 1 year, but blood samples stored at 37°C were stable for no more than 2 weeks. PMID:26912563

  2. Sequential extraction of inorganic mercury in dumped blast furnace sludge.

    PubMed

    Földi, Corinna; Andrée, Corlin-Anna; Mansfeldt, Tim

    2015-10-01

    Blast furnace sludge (BFS) is an industrial waste with elevated mercury (Hg) contents due to the enrichment during the production process of pig iron. To investigate the potential pollution status of dumped BFS, 14 samples with total Hg contents ranging from 3.91 to 20.8 mg kg(-1) from five different locations in Europe were sequentially extracted. Extracts used included demineralized water (fraction 1, F1), 0.1 mol L(-1) CH3COOH + 0.01 mol L(-1) HCl (F2), 1 mol L(-1) KOH (F3), 7.9 mol L(-1) HNO3 (F4), and aqua regia (F5). The total recovery ranged from 72.3 to 114 %, indicating that the procedure was reliable when adapted to this industrial waste. Mercury mainly resided in the fraction of "elemental" Hg (48.5-98.8 %) rather being present as slightly soluble Hg species associated with sludge particles. Minor amounts were found as mercuric sulfide (F5; 0.725-37.3 %) and Hg in crystalline metal ores and silicates (F6; 2.21-15.1 %). The ecotoxically relevant fractions (F1 and F2) were not of significance (F1,

  3. Toxicity of organic and inorganic mercury species in differentiated human neurons and human astrocytes.

    PubMed

    Lohren, Hanna; Blagojevic, Lara; Fitkau, Romy; Ebert, Franziska; Schildknecht, Stefan; Leist, Marcel; Schwerdtle, Tanja

    2015-10-01

    Organic mercury (Hg) species exert their toxicity primarily in the central nervous system. The food relevant Hg species methylmercury (MeHg) has been frequently studied regarding its neurotoxic effects in vitro and in vivo. Neurotoxicity of thiomersal, which is used as a preservative in medical preparations, is to date less characterised. Due to dealkylation of organic Hg or oxidation of elemental Hg, inorganic Hg is present in the brain albeit these species are not able to readily cross the blood brain barrier. This study compared for the first time toxic effects of organic MeHg chloride (MeHgCl) and thiomersal as well as inorganic mercury chloride (HgCl2) in differentiated human neurons (LUHMES) and human astrocytes (CCF-STTG1). The three Hg species differ in their degree and mechanism of toxicity in those two types of brain cells. Generally, neurons are more susceptible to Hg species induced cytotoxicity as compared to astrocytes. This might be due to the massive cellular mercury uptake in the differentiated neurons. The organic compounds exerted stronger cytotoxic effects as compared to inorganic HgCl2. In contrast to HgCl2 exposure, organic Hg compounds seem to induce the apoptotic cascade in neurons following low-level exposure. No indicators for apoptosis were identified for both inorganic and organic mercury species in astrocytes. Our studies clearly demonstrate species-specific toxic mechanisms. A mixed exposure towards all Hg species in the brain can be assumed. Thus, prospectively coexposure studies as well as cocultures of neurons and astrocytes could provide additional information in the investigation of Hg induced neurotoxicity.

  4. Estimation of Nuclear Volume Dependent Fractionation of Mercury Isotopes Using Octanol- Water Partitioning of Inorganic Mercury

    NASA Astrophysics Data System (ADS)

    Ghosh, S.; Bergquist, B. A.; Schauble, E. A.; Blum, J. D.

    2009-05-01

    Mercury is a globally distributed pollutant; the toxicity and biomagnifications in aquatic food chains, even in remote areas, makes it a serious worldwide problem. Similar to other stable isotope systems, the isotopic composition of environmental Hg is potentially a new tool to better understand the biogeochemical cycling, fluxes and anthropogenic impacts of Hg. The promise of Hg isotopes is even more exciting with the recent discovery of large mass independent fractionation (MIF) displayed by the odd Hg isotopes (199Hg and 201Hg). Based on current theory MIF of Hg isotopes can arise either from the non-linear scaling of nuclear volume with mass for heavy isotopes (Nuclear Volume Effect, NVE) or from the magnetic isotope effect (MIE), which is due to the non-zero nuclear spin and nuclear magnetic moments of odd-mass isotopes. In order to interpret and use Hg MIF signatures in nature, both experimental and theoretical work is needed to better understand the controls and expression of MIF along with the underlying mechanisms of MIF. The goal of the current study was to design an experiment that would express the NVE in order to confirm theoretical predictions of the isotopic signature of the NVE for Hg. Unfortunately, both NVE and MIE predict MIF for only the odd isotopes. However since MIE is a kinetic phenomenon only, MIF observed in equilibrium reactions should be attributable to the NVE only. Thus it should be possible to isolate NVE driven MIF from MIE driven MIF. A laboratory experiment was designed on equilibrium octanol-water partitioning of different Hg chloride species. Octanol-water partitioning of Hg depends on the hydrophobicity of the Hg species, so non polar lipophilic species partition into the octanol phase while polar species remain in water phase. At 25 degree Celsius, a Cl- concentration of 1 molar and pH <2, the dominant aqueous phase is HgCl42- while non polar HgCl2 will partition into the octanol phase. Since HgCl42- has a stronger ionic

  5. Renal accumulation and intrarenal distribution of inorganic mercury in the rabbit: Effect of unilateral nephrectomy and dose of mercuric chloride

    SciTech Connect

    Zalups, R.K. )

    1991-06-01

    The effects of unilateral nephrectomy and dose of mercuric chloride on the short-term renal accumulation and intrarenal distribution of inorganic mercury were studied in the rabbit. The renal accumulation of inorganic mercury, on a per gram basis, was increased in uninephrectomized (NPX) rabbits compared with that in sham-operated (SO) rabbits 24 h after the animals received either a nontoxic 2.0 mumol/kg or nephrotoxic 4.0 mumol/kg dose of mercuric chloride. In the NPX rabbits given the 2.0 mumol/kg dose of mercuric chloride, the increased accumulation of inorganic mercury was due to increased accumulation of mercury in the outer stripe of the outer medulla. In the NPX rabbits given the 4.0 mumol/kg dose of mercuric chloride, the increased renal accumulation of mercury appeared to be due to increased accumulation of mercury in both the renal cortex and outer stripe of the outer medulla. Interestingly, no differences in the renal accumulation of inorganic mercury were found between NPX and SO rabbits given a low nontoxic 0.5 mumol/kg dose of mercuric chloride. As the dose of mercuric chloride was increased from 0.5 to 4.0 mumol/kg, the percent of the administered dose of mercury that accumulated in each gram of renal tissue decreased substantially. The findings in the present study indicate that the renal accumulation of inorganic mercury increases after unilateral nephrectomy when certain nontoxic and nephrotoxic doses of mercuric chloride are administered. In addition, they indicate that the percent of the administered dose of mercury that accumulates in the renal tissue of both NPX and SO rabbits decreases as the dose of mercuric chloride is increased.

  6. Submicron silica spheres decorated with silver nanoparticles as a new effective sorbent for inorganic mercury in surface waters.

    PubMed

    Yordanova, Tanya; Vasileva, Penka; Karadjova, Irina; Nihtianova, Diana

    2014-03-21

    An analytical method using silica supported silver nanoparticles as a novel sorbent for the enrichment and determination of inorganic mercury (iHg) in surface water samples has been developed. Silver nanoparticles (AgNPs) were synthesized by a completely green procedure and were deposited onto the amine functionalized surface of silica submicrospheres (SiO2-NH2). The prepared nanocomposite material (SiO2/AgNPs) was characterized by transmission electron microscopy, UV-vis spectroscopy, X-ray diffraction and atomic force microscopy. The sorption and desorption characteristics of the nanosorbent SiO2/AgNPs toward Hg species were investigated by a batch method. An excellent separation of iHg and methylHg was achieved in 20 minutes at pH 2. The high selectivity of the SiO2/AgNPs toward iHg was explained by Hg(ii) reduction and subsequent silver-mercury amalgam formation. The analytical procedure for the enrichment and determination of inorganic mercury in surface waters was developed based on solid phase extraction and ICP-MS measurements. The total Hg content was determined after water sample mineralization. The recoveries reached for iHg in different surface waters e.g. river and Black sea water samples varied from 96-101%. The limits of quantification are 0.002 μg L(-1) and 0.004 μg L(-1) for iHg and total Hg, respectively; the relative standard deviations varied in the ranges of 5-9% and 6-11% for iHg and total Hg, respectively, for Hg content from 0.005 to 0.2 μg L(-1). The accuracy of the procedure developed for total Hg determination was confirmed by a comparative analysis of surface river (ICP-MS) and sea (CV AFS) waters.

  7. Effects of methyl and inorganic mercury exposure on genome homeostasis and mitochondrial function in Caenorhabditis elegans.

    PubMed

    Wyatt, Lauren H; Luz, Anthony L; Cao, Xiou; Maurer, Laura L; Blawas, Ashley M; Aballay, Alejandro; Pan, William K Y; Meyer, Joel N

    2017-04-01

    Mercury toxicity mechanisms have the potential to induce DNA damage and disrupt cellular processes, like mitochondrial function. Proper mitochondrial function is important for cellular bioenergetics and immune signaling and function. Reported impacts of mercury on the nuclear genome (nDNA) are conflicting and inconclusive, and mitochondrial DNA (mtDNA) impacts are relatively unknown. In this study, we assessed genotoxic (mtDNA and nDNA), metabolic, and innate immune impacts of inorganic and organic mercury exposure in Caenorhabditis elegans. Genotoxic outcomes measured included DNA damage, DNA damage repair (nucleotide excision repair, NER; base excision repair, BER), and genomic copy number following MeHg and HgCl2 exposure alone and in combination with known DNA damage-inducing agents ultraviolet C radiation (UVC) and hydrogen peroxide (H2O2), which cause bulky DNA lesions and oxidative DNA damage, respectively. Following exposure to both MeHg and HgCl2, low-level DNA damage (∼0.25 lesions/10kb mtDNA and nDNA) was observed. Unexpectedly, a higher MeHg concentration reduced damage in both genomes compared to controls. However, this observation was likely the result of developmental delay. In co-exposure treatments, both mercury compounds increased initial DNA damage (mtDNA and nDNA) in combination with H2O2 exposure, but had no impact in combination with UVC exposure. Mercury exposure both increased and decreased DNA damage removal via BER. DNA repair after H2O2 exposure in mercury-exposed nematodes resulted in damage levels lower than measured in controls. Impacts to NER were not detected. mtDNA copy number was significantly decreased in the MeHg-UVC and MeHg-H2O2 co-exposure treatments. Mercury exposure had metabolic impacts (steady-state ATP levels) that differed between the compounds; HgCl2 exposure decreased these levels, while MeHg slightly increased levels or had no impact. Both mercury species reduced mRNA levels for immune signaling-related genes, but

  8. MRP2 and the handling of mercuric ions in rats exposed acutely to inorganic and organic species of mercury

    SciTech Connect

    Bridges, Christy C. Joshee, Lucy; Zalups, Rudolfs K.

    2011-02-15

    Mercuric ions accumulate preferentially in renal tubular epithelial cells and bond with intracellular thiols. Certain metal-complexing agents have been shown to promote extraction of mercuric ions via the multidrug resistance-associated protein 2 (MRP2). Following exposure to a non-toxic dose of inorganic mercury (Hg{sup 2+}), in the absence of complexing agents, tubular cells are capable of exporting a small fraction of intracellular Hg{sup 2+} through one or more undetermined mechanisms. We hypothesize that MRP2 plays a role in this export. To test this hypothesis, Wistar (control) and TR{sup -} rats were injected intravenously with a non-nephrotoxic dose of HgCl{sub 2} (0.5 {mu}mol/kg) or CH{sub 3}HgCl (5 mg/kg), containing [{sup 203}Hg], in the presence or absence of cysteine (Cys; 1.25 {mu}mol/kg or 12.5 mg/kg, respectively). Animals were sacrificed 24 h after exposure to mercury and the content of [{sup 203}Hg] in blood, kidneys, liver, urine and feces was determined. In addition, uptake of Cys-S-conjugates of Hg{sup 2+} and methylmercury (CH{sub 3}Hg{sup +}) was measured in inside-out membrane vesicles prepared from either control Sf9 cells or Sf9 cells transfected with human MRP2. The amount of mercury in the total renal mass and liver was significantly greater in TR{sup -} rats than in controls. In contrast, the amount of mercury in urine and feces was significantly lower in TR{sup -} rats than in controls. Data from membrane vesicles indicate that Cys-S-conjugates of Hg{sup 2+} and CH{sub 3}Hg{sup +} are transportable substrates of MRP2. Collectively, these data indicate that MRP2 plays a role in the physiological handling and elimination of mercuric ions from the kidney.

  9. Diversity of mercury resistance determinants among Bacillus strains isolated from sediment of Minamata Bay.

    PubMed

    Narita, Masaru; Chiba, Kazuyuki; Nishizawa, Hiroshi; Ishii, Hidenori; Huang, Chieh-Chen; Kawabata, Zen'ichiro; Silver, Simon; Endo, Ginro

    2003-06-06

    Thirty mercury-resistant (Hg R) Bacillus strains were isolated from mercury-polluted sediment of Minamata Bay, Japan. Mercury resistance phenotypes were classified into broad-spectrum (resistant to inorganic Hg(2+) and organomercurials) and narrow-spectrum (resistant to inorganic Hg(2+) and sensitive to organomercurials) groups. Polymerase chain reaction (PCR) product sizes and the restriction nuclease site maps of mer operon regions from all broad-spectrum Hg R Bacillus were identical to that of Bacillus megaterium MB1. On the other hand, the PCR products of the targeted merP (extracellular mercury-binding protein gene) and merA (intracellular mercury reductase protein gene) regions from the narrow-spectrum Hg R Bacillus were generally smaller than those of the B. megaterium MB1 mer determinant. Diversity of gene structure configurations was also observed by restriction fragment length polymorphism (RFLP) profiles of the merA PCR products from the narrow-spectrum Hg R Bacillus. The genetic diversity of narrow-spectrum mer operons was greater than that of broad-spectrum ones.

  10. Oral and intramuscular toxicity of inorganic and organic mercury chloride to growing quail

    USGS Publications Warehouse

    Hill, E.F.; Soares, J.H.

    1987-01-01

    The lethal toxicity of inorganic (HgCl2) and organic (CH3HgCl) mercury chloride was compared for Coturnix (Japanese quail, Coturnix japonica) of different ages from hatch through adulthood by single-dose acute oral and intramuscular injections and by a 5-d dietary trial. Sublethal mercury toxicity was studied by evaluation of plasma and brain cholinesterase activity. CH3HgCl was more toxic than HgCl2 in all tests at each age tested. LD50s consistently increased over the first 4 wk for both acute methods and both mercurials and then stabilized. The striking difference between single-dose acute and 5-d dietary tests was that CH3HgCl averaged about twice as toxic as HgCl2 by both acute methods, compared to 100 times as toxic by the dietary method. For example, at 2 wk of age, the oral LD50s for CH3HgCl and HgCl2 were 18 and 42 mg/kg and the dietary LC50s were 47 and 5086 ppm. When birds were fed HgCl2 and developed clinical signs of intoxication, they could recover once treatment was withdrawn; however, on CH3HgCl, clinical signs often commenced after treatment was withdrawn, and then actually intensified for several days and culminated in death.

  11. Organic and inorganic amendment application on mercury-polluted soils: effects on soil chemical and biochemical properties.

    PubMed

    García-Sánchez, Mercedes; Klouza, Martin; Holečková, Zlata; Tlustoš, Pavel; Száková, Jiřina

    2016-07-01

    On the basis of a previous study performed in our laboratory, the use of organic and inorganic amendments can significantly modify the Hg mobility in soil. We have compared the effectiveness of organic and inorganic amendments such as digestate and fly ash, respectively, reducing the Hg mobility in Chernozem and Luvisol soils differing in their physicochemical properties. Hence, the aim of this work was to compare the impact of digestate and fly ash application on the chemical and biochemical parameters in these two mercury-contaminated soils in a model batch experiment. Chernozem and Luvisol soils were artificially contaminated with Hg and then incubated under controlled conditions for 21 days. Digestate and fly ash were applied to both soils in a dose of 10 and 1.5 %, respectively, and soil samples were collected after 1, 7, 14, and 21 days of incubation. The presence of Hg in both soils negatively affected to processes such as nitrification, provoked a decline in the soil microbial biomass C (soil microbial biomass C (MBC)), and the microbial activities (arylsulfatase, and β-glucosaminidase) in both soils. Meanwhile, the digestate addition to Chernozem and Luvisol soils contaminated with Hg improved the soil chemical properties (pH, dissolved organic carbon (DOC), N (Ntot), inorganic-N forms (N-NH4 (+) and N-NO3 (-))), as consequence of high content in C and N contained in digestate. Likewise, the soil MBC and soil microbial activities (dehydrogenase, arylsulfatase, and β-glucosaminidase) were greatly enhanced by the digestate application in both soils. In contrast, fly ash application did not have a remarkable positive effect when compared to digestate in Chernozem and Luvisol soil contaminated with mercury. These results may indicate that the use of organic amendments such as digestate considerably improved the soil health in Chernozem and Luvisol compared with fly ash, alleviating the detrimental impact of Hg. Probably, the chemical properties present in

  12. A comprehensive study of Mercury and MESSENGER orbit determination

    NASA Astrophysics Data System (ADS)

    Genova, Antonio; Mazarico, Erwan; Goossens, Sander; Lemoine, Frank G.; Neumann, Gregory A.; Nicholas, Joseph B.; Rowlands, David D.; Smith, David E.; Zuber, Maria; Solomon, Sean C.

    2016-10-01

    The MErcury, Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft orbited the planet Mercury for more than 4 years. The probe started its science mission in orbit around Mercury on 18 March 2011. The Mercury Laser Altimeter (MLA) and radio science system were the instruments dedicated to geodetic observations of the topography, gravity field, orientation, and tides of Mercury. X-band radio-tracking range-rate data collected by the NASA Deep Space Network (DSN) allowed the determination of Mercury's gravity field to spherical harmonic degree and order 100, the planet's obliquity, and the Love number k2.The extensive range data acquired in orbit around Mercury during the science mission (from April 2011 to April 2015), and during the three flybys of the planet in 2008 and 2009, provide a powerful dataset for the investigation of Mercury's ephemeris. The proximity of Mercury's orbit to the Sun leads to a significant perihelion precession attributable to the gravitational flattening of the Sun (J2) and the Parameterized Post-Newtonian (PPN) coefficients γ and β, which describe the space curvature produced by a unit rest mass and the nonlinearity in superposition of gravity, respectively. Therefore, the estimation of Mercury's ephemeris can provide crucial information on the interior structure of the Sun and Einstein's general theory of relativity. However, the high correlation among J2, γ, and β complicates the combined recovery of these parameters, so additional assumptions are required, such as the Nordtvedt relationship η = 4β - γ - 3.We have modified our orbit determination software, GEODYN II, to enable the simultaneous integration of the spacecraft and central body trajectories. The combined estimation of the MESSENGER and Mercury orbits allowed us to determine a more accurate gravity field, orientation, and tides of Mercury, and the values of GM and J2 for the Sun, where G is the gravitational constant and M is the solar mass

  13. Chronic insomnia in workers poisoned by inorganic mercury: psychological and adaptive aspects.

    PubMed

    Rossini, S R; Reimão, R; Lefèvre, B H; Medrado-Faria, M A

    2000-03-01

    Insomnia is one of the symptoms of inorganic mercury poisoning (IMP). The objective of this study is to analyze the chief psychological aspects in the adjustment of workers with chronic insomnia associated with IMP. For this purpose the Preventive Clinical Interview and the Ryad Simon Operational Adaptive Diagnostic Scale (Escala Diagnóstica Adaptativa Operacionalizada-EDAO) were utilized. Fifteen subjects with mean age of 40 years (10 males and 5 females) were studied. Nine were diagnosed with High Adaptive Inefficacy, five with Moderate Inefficient Adaptation and only one with Mild Inefficient Adaptation. Impairment occurred in four adaptive sectors: affective relationship, social-cultural, productivity and organic. Adaptive efficiency indicated that in all the 15 subjects studied the adaptive solutions were frustrating and led to psychic suffering and/or environmental conflict confirming the severity of the involvement in chronic IMP.

  14. Mercury exposure in French Guiana: Levels and determinants

    SciTech Connect

    Cordier, S.; Mandereau, L.; Grasmick, C.; Paquier-Passelaigue, M.; Weber, J.P.; Jouan, M.

    1998-07-01

    Mercury is used widely for gold extraction in French Guiana and throughout the entire Amazon basin. To evaluate contamination among the general population, the authors chose individuals who attended 13 health centers and maternity hospitals dispersed geographically across the territory and served Guiana`s different populations. Five hundred individuals (109 pregnant women, 255 other adults, and 136 children) who received care at one of the centers were selected randomly for this study. Each individual answered a questionnaire and provided a hair sample. The authors determined mercury in hair with atomic absorption spectrometry. The following mean levels of mercury were observed: 1.6 {micro}g/g among pregnant women; 3.4 {micro}g/g among other adults; and 2.5 {micro}g/g among children. Diet factors contributed the most to mercury levels, especially consumption of freshwater fish and livers from game. Other factors, including age, dental amalgams, use of skin-lightening cosmetics, and residence near a gold-mining community, did not contribute significantly to mercury levels. Overall, 12% of the samples contained mercury levels in excess of 10 {micro}g/g, but in some Amerindian communities up to 79% of the children had hair mercury levels that exceeded 10 {micro}g/g. The results of this study indicated that (a) diet played a predominant role in total mercury burden, and (b) in some communities, mercury contamination exceeded safe levels.

  15. 'Reactive' Inorganic Mercury: A critical examination of preservation and storage techniques

    NASA Astrophysics Data System (ADS)

    Beaulieu, E.; Marvin-DiPasquale, M. C.; Alpers, C. N.; Fleck, J.

    2012-12-01

    Mercury (Hg) studies in the Sacramento-San Joaquin Delta and San Francisco Bay and elsewhere suggest that 'reactive' (stannous chloride reducible) inorganic mercury (Hg(II)R) in sediment is a reasonable proxy measurement for the in situ pool of inorganic Hg(II) that is truly available to bacteria that produce toxic methylmercury (MeHg) from Hg(II). This study rigorously tested the effects of sample handling, holding time, and storage temperature (prior to Hg(II)R analysis), with the goal of identifying an optimal sample treatment and preservation protocol for Hg(II)R analysis. Because specific sediment properties such as organic content, grain size, redox conditions, water content, and total reduced sulfur concentration can affect Hg(II)R concentration, sediment with a range of these parameters was collected from four distinct Hg-contaminated regions surrounding the Sacramento-San Joaquin Delta and San Francisco Bay. For most sites, there was a statistically significant difference in Hg(II)R concentration related to sample holding time (0 to 180 days), but no significant difference related to sample storage temperature (-80 to 5 °C). Samples exposed to oxic conditions did not differ significantly in Hg(II)R from those subsampled in a glove bag under anoxic conditions. The results from this study will be used to develop a standard set of practices with respect to sediment sub-sampling and preservation when Hg(II)R is a targeted analyte. Hg(II)R was identified in the Delta Regional Ecosystem Restoration Implementation Plan (DRERIP) Hg Conceptual Model as an important driver affecting the fate and transport of Hg in the Sacramento-San Joaquin Delta ecosystem.

  16. Isotopic Composition of Inorganic Mercury and Methylmercury Downstream of a Historical Gold Mining Region.

    PubMed

    Donovan, Patrick M; Blum, Joel D; Singer, Michael Bliss; Marvin-DiPasquale, Mark; Tsui, Martin T K

    2016-02-16

    We measured total mercury (THg) and monomethyl mercury (MMHg) concentrations and mercury (Hg) isotopic compositions in sediment and aquatic organisms from the Yuba River (California, USA) to identify Hg sources and biogeochemical transformations downstream of a historical gold mining region. Sediment THg concentrations and δ(202)Hg decreased from the upper Yuba Fan to the lower Yuba Fan and the Feather River. These results are consistent with the release of Hg during gold mining followed by downstream mixing and dilution. The Hg isotopic composition of Yuba Fan sediment (δ(202)Hg = -0.38 ± 0.17‰ and Δ(199)Hg = 0.04 ± 0.03‰; mean ± 1 SD, n = 7) provides a fingerprint of inorganic Hg (IHg) that could be methylated locally or after transport downstream. The isotopic composition of MMHg in the Yuba River food web was estimated using biota with a range of %MMHg (the percent of THg present as MMHg) and compared to IHg in sediment, algae, and the food web. The estimated δ(202)Hg of MMHg prior to photodegradation (-1.29 to -1.07‰) was lower than that of IHg and we suggest this is due to mass-dependent fractionation (MDF) of up to -0.9‰ between IHg and MMHg. This result is in contrast to net positive MDF (+0.4 to +0.8‰) previously observed in lakes, estuaries, coastal oceans, and forests. We hypothesize that this unique relationship could be due to differences in the extent or pathway of biotic MMHg degradation in stream environments.

  17. Isotopic composition of inorganic mercury and methylmercury downstream of a historical gold mining region

    USGS Publications Warehouse

    Donovan, Patrick M.; Blum, Joel D.; Singer, Michael B.; Marvin-DiPasquale, Mark C.; Tsui, Martin T.K.

    2016-01-01

    We measured total mercury (THg) and monomethyl mercury (MMHg) concentrations and mercury (Hg) isotopic compositions in sediment and aquatic organisms from the Yuba River (California, USA) to identify Hg sources and biogeochemical transformations downstream of a historical gold mining region. Sediment THg concentrations and δ202Hg decreased from the upper Yuba Fan to the lower Yuba Fan and the Feather River. These results are consistent with the release of Hg during gold mining followed by downstream mixing and dilution. The Hg isotopic composition of Yuba Fan sediment (δ202Hg = −0.38 ± 0.17‰ and Δ199Hg = 0.04 ± 0.03‰; mean ± 1 SD, n = 7) provides a fingerprint of inorganic Hg (IHg) that could be methylated locally or after transport downstream. The isotopic composition of MMHg in the Yuba River food web was estimated using biota with a range of %MMHg (the percent of THg present as MMHg) and compared to IHg in sediment, algae, and the food web. The estimated δ202Hg of MMHg prior to photodegradation (−1.29 to −1.07‰) was lower than that of IHg and we suggest this is due to mass-dependent fractionation (MDF) of up to −0.9‰ between IHg and MMHg. This result is in contrast to net positive MDF (+0.4 to +0.8‰) previously observed in lakes, estuaries, coastal oceans, and forests. We hypothesize that this unique relationship could be due to differences in the extent or pathway of biotic MMHg degradation in stream environments.

  18. Differential acclimation of a marine diatom to inorganic mercury and methylmercury exposure.

    PubMed

    Wu, Yun; Wang, Wen-Xiong

    2013-08-15

    Aquatic organisms originating from metal polluted water may exhibit differences in their sensitivity to metals, but the underlying physiological mechanisms resulting in such responses have not been well reported. In the present study, a marine diatom Thalassiosira weissflogii was chronically exposed to different inorganic mercury (Hg(II), 0.5 and 5 μg Hg/L) or methylmercury (MeHg, 0.02 and 0.4 μg Hg/L) concentrations for over 18 generations. We then quantified the changes in the Hg(II) or MeHg sensitivity, Hg accumulation, subcellular distribution, as well as thiol compound induction in the diatoms. We found an unchanged tolerance to Hg(II) but an enhanced tolerance to MeHg in the preconditioned T. weissflogii. The underlying mechanisms may be related to the changes in cellular mercury accumulation and the detoxification ability of the cells. Specifically, exposure to high-Hg(II) led to increased metal distribution in cellular debris fraction, as well as the induction of a variety of non-protein thiol compounds, but the uptake kinetics was not significantly modified by Hg(II) exposure. Instead, exposure to high-MeHg decreased the mercury uptake rate along with the synthesis of glutathione (GSH) and (γ-EC)₂-Gly (PC₂). All these responses contributed to the different tolerance developments between Hg(II) and MeHg. This study suggests that moderation of Hg bioavailability was probably more important than internal detoxification in the development of Hg acclimation in marine diatoms.

  19. Bioaccumulation and metallothionein response in the Asiatic clam (Corbicula fluminea) after experimental exposure to cadmium and inorganic mercury

    SciTech Connect

    Baudrimont, M.; Metivaud, J.; Maury-Brachet, R.; Ribeyre, F.; Boudou, A.

    1997-10-01

    The involvement of metallothioneins (MTs) in cadmium (Cd) and inorganic mercury (Hg[II]) bioaccumulation by the freshwater bivalve Corbicula fluminea was experimentally investigated after 0, 15, 30 and 45 d of exposure from the water column source. Three levels of contamination were studied for each metal: 0, 5, and 35 {micro}g Cd/L and 0, 1.45, and 5 {micro}g Hg/L, with two replicates per condition. Forty eight experimental units (EUs) were conducted simultaneously. The mollusks were fed twice a week by additions of phytoplanktonic algae. Quantification of MTs was done by Hg-saturation assay, using cold Hg(II). A partial purification of these proteins was conducted by gel-filtration chromatography, followed by Cd determinations in the different eluted fractions. Results at the whole organism (soft tissues) and organ or tissue group (gills, mantle, foot, visceral mass) levels show high metal concentrations, with a fourfold greater accumulation of inorganic Hg than Cd after 30 d exposure at the same concentration of 5 {micro}g/L. Gills and visceral mass were the principal storage compartments. A significant increase in MT concentrations was revealed in these two organs after exposure to Cd: ratios between the MT concentrations in contaminated and control mollusks were 2.4 and 2.8, respectively, for 5 and 35 {micro}g Cd/L. Cd burdens in the cytosol and in {le}18-kDa protein fractions, similar to purified mammal MTs, correspond to 30 and 14% of the total Cd accumulated in the whole organisms. No significant increase in MT biosynthesis was observed after exposure to inorganic Hg, despite the high metal concentrations in the organs.

  20. Determination of mercury species in fish reference materials by gas chromatography-atomic fluorescence detection after closed-vessel microwave-assisted extraction.

    PubMed

    Nevado, Juan José Berzas; Martín-Doimeadios, Rosa Carmen Rodríguez; Bernardo, Francisco Javier Guzmán; Moreno, María Jiménez

    2005-11-04

    A simple and rapid method has been developed for speciation analysis of inorganic mercury and monomethylmercury (MMHg) in biological tissues. The procedure is based on the quantitative closed-vessel microwave-assisted leaching of mercury from biological samples with an alkaline extractant. The extracted mercury species are ethylated and analysed by capillary gas chromatography coupled to an atomic fluorescence detector via pyrolysis (CGC-pyro-AFS). The coupling between capillary gas chromatography and atomic fluorescence detector was optimized with the aim of minimizing the detection limits and time necessary for the species-selective determination of mercury compounds. The use of closed-vessel microwave-assisted extraction along with no clean-up steps before the ethylation leads to a significant total analysis time decrease with respect to similar procedures. The detection limit was 2 pg for MMHg (as Hg) and 1 pg for inorganic mercury. The method was validated by the analysis of DORM-2 (dogfish muscle) and DOLT-3 (dogfish liver) certified reference materials. The inorganic mercury and methylmercury concentrations found were in good agreement with the certified values. Recovery studies of fish muscle tissue spiked with inorganic mercury and MMHg were done to check the reliability of the method. In all cases satisfactory recoveries (92-105%) were obtained.

  1. Divalent inorganic reactive gaseous mercury emissions from a mercury cell chlor-alkali plant and its impact on near-field atmospheric dry deposition

    NASA Astrophysics Data System (ADS)

    Landis, Matthew S.; Keeler, Gerald J.; Al-Wali, Khalid I.; Stevens, Robert K.

    The emission of inorganic divalent reactive gaseous mercury (RGM) from a mercury cell chlor-alkali plant (MCCAP) cell building and the impact on near field (100 km) dry deposition was investigated as part of a larger collaborative study between EPA, University of Michigan, Oak Ridge National Laboratory, Chlorine Institute, and Olin Corporation in February 2000. Measurements in the cell building roof vent showed that RGM constituted 2.1±0.7% (median±variance) of the concurrently measured elemental gaseous mercury (Hg 0). This relationship was used to calculate an estimated RGM emission rate from the cell building roof vent of 10.4 g day -1. The percentage of RGM/Hg 0 at ambient monitoring sites 350 m (1.5%) and 800 m (1.3%) away while being impacted by cell building emissions suggests the rapid deposition of RGM species. The observed 2% relative emission of RGM/Hg 0 was substantially lower than the 30% estimate utilized by EPA to model the impact of MCCAPs for the 1997 Mercury Report to Congress. However, the MCCAP was still found to present a significant impact on near field mercury atmospheric dry deposition. A Lagrangian transport and deposition modeling framework using only emissions from the MCCAP found the mean annualized dry deposition of mercury within a 10 km radius of the facility contributed the annual equivalent of 4.6 μg m -2. For comparison, the total annual wet mercury deposition measured at the Savannah River National Mercury Deposition Network sampling site ˜30 km away was 9.8 μg m -2.

  2. Flow injection-chemical vapor generation atomic fluorescence spectrometry hyphenated system for organic mercury determination: A step forward

    NASA Astrophysics Data System (ADS)

    Angeli, Valeria; Biagi, Simona; Ghimenti, Silvia; Onor, Massimo; D'Ulivo, Alessandro; Bramanti, Emilia

    2011-11-01

    Monomethylmercury and ethylmercury were determined on line using flow injection-chemical vapor generation atomic fluorescence spectrometry without neither requiring a pre-treatment with chemical oxidants, nor UV/MW additional post column interface, nor organic solvents, nor complexing agents, such as cysteine. Inorganic mercury, monomethylmercury and ethylmercury were detected by atomic fluorescence spectrometry in an Ar/H 2 miniaturized flame after sodium borohydride reduction to Hg 0, monomethylmercury hydride and ethylmercury hydride, respectively. The effect of mercury complexing agent such as cysteine, ethylendiaminotetracetic acid and HCl with respect to water and Ar/H 2 microflame was investigated. The behavior of inorganic mercury, monomethylmercury and ethylmercury and their cysteine-complexes was also studied by continuous flow-chemical vapor generation atomic fluorescence spectrometry in order to characterize the reduction reaction with tetrahydroborate. When complexed with cysteine, inorganic mercury, monomethylmercury and ethylmercury cannot be separately quantified varying tetrahydroborate concentration due to a lack of selectivity, and their speciation requires a pre-separation stage (e.g. a chromatographic separation). If not complexed with cysteine, monomethylmercury and ethylmercury cannot be separated, as well, but their sum can be quantified separately with respect to inorganic mercury choosing a suitable concentration of tetrahydroborate (e.g. 10 - 5 mol L - 1 ), thus allowing the organic/inorganic mercury speciation. The detection limits of the flow injection-chemical vapor generation atomic fluorescence spectrometry method were about 45 nmol L - 1 (as mercury) for all the species considered, a relative standard deviation ranging between 1.8 and 2.9% and a linear dynamic range between 0.1 and 5 μmol L - 1 were obtained. Recoveries of monomethylmercury and ethylmercury with respect to inorganic mercury were never less than 91%. Flow injection

  3. Automated continuous monitoring of inorganic and total mercury in wastewater and other waters by flow-injection analysis and cold-vapour atomic absorption spectrometry

    PubMed Central

    Birnie, S. E.

    1988-01-01

    An automated continuous monitoring system for the determination of inorganic and total mercury by flow-injection analysis followed by cold-vapour atomic absorption spectrometry is described. The method uses a typical flow-injection manifold where digestion and reduction of the injected sample takes place. Mercury is removed by aeration from the flowing stream in a specially designed air-liquid separator and swept into a silica cell for absorption measurement at a wavelength of 253.7 nm. A calibration curve up to 10 μg Hg ml-1 using three different path length cells is obtained with a detection limit of 0.02 μg Hg ml-1. The sampling rate of an injection every 3 min produces 20 results per hour from a flowing stream. PMID:18925201

  4. Transport of thiol-conjugates of inorganic mercury in human retinal pigment epithelial cells

    SciTech Connect

    Bridges, Christy C. . E-mail: bridges_cc@mercer.edu; Battle, Jamie R.; Zalups, Rudolfs K.

    2007-06-01

    Inorganic mercury (Hg{sup 2+}) is a prevalent environmental contaminant to which exposure to can damage rod photoreceptor cells and compromise scotopic vision. The retinal pigment epithelium (RPE) likely plays a role in the ocular toxicity associated with Hg{sup 2+} exposure in that it mediates transport of substances to the photoreceptor cells. In order for Hg{sup 2+} to access photoreceptor cells, it must first be taken up by the RPE, possibly by mechanisms involving transporters of essential nutrients. In other epithelia, Hg{sup 2+}, when conjugated to cysteine (Cys) or homocysteine (Hcy), gains access to the intracellular compartment of the target cells via amino acid and organic anion transporters. Accordingly, the purpose of the current study was to test the hypothesis that Cys and Hcy S-conjugates of Hg{sup 2+} utilize amino acid transporters to gain access into RPE cells. Time- and temperature-dependence, saturation kinetics, and substrate-specificity of the transport of Hg{sup 2+}, was assessed in ARPE-19 cells exposed to the following S-conjugates of Hg{sup 2+}: Cys (Cys-S-Hg-S-Cys), Hcy (Hcy-S-Hg-S-Hcy), N-acetylcysteine (NAC-S-Hg-S-NAC) or glutathione (GSH-S-Hg-S-GSH). We discovered that only Cys-S-Hg-S-Cys and Hcy-S-Hg-S-Hcy were taken up by these cells. This transport was Na{sup +}-dependent and was inhibited by neutral and cationic amino acids. RT-PCR analyses identified systems B{sup 0,+} and ASC in ARPE-19 cells. Overall, our data suggest that Cys-S-Hg-S-Cys and Hcy-S-Hg-S-Hcy are taken up into ARPE-19 cells by Na-dependent amino acid transporters, possibly systems B{sup 0,+} and ASC. These amino acid transporters may play a role in the retinal toxicity observed following exposure to mercury.

  5. Organic and inorganic mercurials have distinct effects on cellular thiols, metal homeostasis, and Fe-binding proteins in Escherichia coli

    PubMed Central

    LaVoie, Stephen P.; Mapolelo, Daphne T.; Cowart, Darin M.; Polacco, Benjamin J.; Johnson, Michael K.; Scott, Robert A.; Miller, Susan M.; Summers, Anne O.

    2015-01-01

    The protean chemical properties of the toxic metal mercury (Hg) have made it attractive in diverse applications since antiquity. However, growing public concern has led to an international agreement to decrease its impact on health and the environment. During a recent proteomics study of acute Hg exposure in E. coli, we also examined the effects of inorganic and organic Hg compounds on thiol- and metal- homeostases. On brief exposure, lower concentrations of divalent inorganic mercury Hg(II) blocked bulk cellular thiols and protein-associated thiols more completely than higher concentrations of monovalent organomercurials, phenylmercuric acetate (PMA) and merthiolate (MT). Cells bound Hg(II) and PMA in excess of their available thiol ligands; X-ray absorption spectroscopy indicated nitrogens as likely additional ligands. The mercurials released protein bound iron (Fe) more effectively than common organic oxidants and all disturbed the Na+/K+ electrolyte balance, but none provoked efflux of six essential transition metals including Fe. PMA and MT made stable cysteine monothiol adducts in many Fe-binding proteins, but stable Hg(II) adducts were only seen in CysXxx(n)Cys peptides. We conclude that on acute exposure: (a) the distinct effects of mercurials on thiol- and Fe-homeostases reflected their different uptake and valences; (b) their similar effects on essential metal- and electrolyte-homeostases reflected the energy-dependence of these processes; and (c) peptide phenylmercury-adducts were more stable or detectable in mass spectrometry than Hg(II)-adducts. These first in vivo observations in a well-defined model organism reveal differences upon acute exposure to inorganic and organic mercurials that may underlie their distinct toxicology. PMID:26498643

  6. [A case of chronic inorganic mercury poisoning with progressive intentional tremor and remarkably prolonged latency of P300].

    PubMed

    Shikata, E; Mochizuki, Y; Oishi, M; Takasu, T

    1998-12-01

    A 59-year-old man showed slowly progressive intentional tremor for 40 years prior to first visit to us in 1996. He was exposed to mercury vapor for about 3 years (1956-1959) and the diagnosis of chronic inorganic mercury poisoning was made. Hasegawa dementia scale-revised (HDS-R), mini-mental state (MMS) examination and P300 examination were performed. HDS-R and MMS were within normal range but the latency of P300 was remarkably prolonged. His tremor was considered to be due to chronic inorganic poisoning because there were no other causes and the frequency of his tremor was 3-4 Hz. which was lower than that in essential tremor. The prolonged P300 latency was also considered to be due to the same cause because there were no other causes and the head MRI were normal. Chronic inorganic mercury poisoning has been reported to produce organic changes in the brain and P300 is considered to be useful to detect these changes.

  7. Inorganic mercury dissociates preassembled Fas/CD95 receptor oligomers in T lymphocytes

    SciTech Connect

    Ziemba, Stamatina E.; McCabe, Michael J.; Rosenspire, Allen J. . E-mail: arosensp@sun.science.wayne.edu

    2005-08-15

    Genetically susceptible rodents exposed to low burdens of inorganic mercury (Hg{sup 2+}) develop autoimmune disease. Previous studies have shown that low, noncytotoxic levels of Hg{sup 2+} inhibit Fas-mediated apoptosis in T cells. These results suggest that inhibition of the Fas death receptor pathway potentially contributes to autoimmune disease after Hg{sup 2+} exposure, as a consequence of disruption of peripheral tolerance. The formation of active death inducing signaling complexes (DISC) following CD95/Fas receptor oligomerization is a primary step in the Fas-mediated apoptotic pathway. Other recent studies have shown that Hg{sup 2+} at concentrations that inhibit apoptosis also inhibit formation of active DISC, suggesting that inhibition of DISC is the mechanism responsible for Hg{sup 2+}-mediated inhibition of apotosis. Preassociated Fas receptors have been implicated as key elements necessary for the production of functional DISC. We present evidence in this study showing that low and nontoxic concentrations of Hg{sup 2+} induce the dissociation of preassembled Fas receptor complexes in Jurkat T cells. Thus, this Hg{sup 2+}-induced event should subsequently decrease the amount of preassembled Fas available for DISC formation, potentially resulting in the attenuation of Fas-mediated apoptosis in T lymphocytes.

  8. Understanding reduced inorganic mercury accumulation in rice following selenium application: Selenium application routes, speciation and doses.

    PubMed

    Tang, Wenli; Dang, Fei; Evans, Douglas; Zhong, Huan; Xiao, Lin

    2017-02-01

    Selenium (Se) has recently been demonstrated to reduce inorganic mercury (IHg) accumulation in rice plants, while its mechanism is far from clear. Here, we aimed at exploring the potential effects of Se application routes (soil or foliar application with Se), speciation (selenite and selenate), and doses on IHg-Se antagonistic interactions in soil-rice systems. Results of our pot experiments indicated that soil application but not foliar application could evidently reduce tissue IHg concentrations (root: 0-48%, straw: 15-58%, and brown rice: 26-74%), although both application routes resulted in comparable Se accumulation in aboveground tissues. Meanwhile, IHg distribution in root generally increased with amended Se doses in soil, suggesting antagonistic interactions between IHg and Se in root. These results provided initial evidence that IHg-Se interactions in the rhizosphere (i.e., soil or rice root), instead of those in the aboveground tissues, could probably be more responsible for the reduced IHg bioaccumulation following Se application. Furthermore, Se dose rather than Se speciation was found to be more important in controlling IHg accumulation in rice. Our findings regarding the importance of IHg-Se interactions in the rhizosphere, together with the systematic investigation of key factors affecting IHg-Se antagonism and IHg bioaccumulation, advance our understanding of Hg dynamics in soil-rice systems.

  9. Intestinal solubilization of particle-associated organic and inorganic mercury as a measure of bioavailability to benthic invertebrates

    SciTech Connect

    Lawrence, A.L.; McAloon, K.M.; Mason, R.P.; Mayer, L.M.

    1999-06-01

    The bioavailability of particle-associated inorganic mercury (Hg{sub I}) and monomethylmercury (MMHg) was evaluated in vitro using digestive fluid of the deposit feeding lugworm, Arenicola marina. Digestive fluid, removed from the midgut of the polychaete, was incubated with contaminated sediment, and the proportion of Hg{sub I} or MMHg solubilized by the digestive fluid was determined. Digestive fluid was found to be a more effective solvent than seawater in solubilizing particle-associated Hg{sub I} or MMHg. A greater percentage of MMHg than Hg{sub I} was solubilized from most sediments, suggesting that sediment-associated MMHg is generally more readily available from sediment for biological uptake. The proportion of MMHg released from the sediment was inversely correlated with sediment organic matter content, decreasing exponentially with increasing organic matter content of the sediment. The results for Hg{sub I} were equivocal. MMHg bioaccumulation factors (BAFs) from previous studies showed a similar trend with organic content of sediment, suggesting that solubilization may be the process limiting the bioaccumulation of particle-bound MMHg. It is concluded that in vitro extraction with a deposit feeder`s digestive fluid provides a potential tool to study the process of Hg bioaccumulation via ingestion routes, although its application to various sediments and organisms needs further investigation.

  10. Selective determination of elemental mercury in blood and urine exposed to mercury vapor in vitro.

    PubMed

    Satoh, H; Hursh, J B; Clarkson, T W; Suzuki, T

    1981-06-01

    A method is described to ensure quantitative measurement of dissolved mercury vapor (Hg0) in blood and urine. Room air passed through samples of blood and urine carries with it all the dissolved Hg0 but leaves behind all the ionic mercury (Hg++). Oxidation of Hg0 to Hg++ in blood samples is completely inhibited by addition of ethanol (0.5% v/v). To minimize error due to evaporation of Hg0, it is suggested that samples should be stored at 0 degree C and Hg0 should be determined within 60 min of collection of blood samples and within 10 min of urine samples.

  11. In vitro evaluation of inorganic and methyl mercury mediated cytotoxic effect on neural cells derived from different animal species.

    PubMed

    Tong, Jing; Wang, Youwei; Lu, Yuanan

    2016-03-01

    To extend the current understanding of the mercury-mediated cytotoxic effect, five neural cell lines established from different animal species were comparatively analyzed using three different endpoint bioassays: thiazolyl blue tetrazolium bromide, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay (MTT), neutral red uptake assay (NRU), and Coomassie blue assay (CB). Following a 24-hr exposure to selected concentrations of mercury chloride (HgCl2) and methylmercury (II) chloride (MeHgCl), the cytotoxic effect on test cells was characterized by comparing their 50% inhibition concentration (IC50) values. Experimental results indicated that both these forms of mercury were toxic to all the neural cells, but at very different degrees. The IC50 values of MeHgCl among these cell lines ranged from 1.15±0.22 to 10.31±0.70μmol/L while the IC50 values for HgCl2 were much higher, ranging from 6.44±0.36 to 160.97±19.63μmol/L, indicating the more toxic nature of MeHgCl. The IC50 ratio between HgCl2 and MeHgCl ranged from 1.75 to 96.0, which confirms that organic mercury is much more toxic to these neural cells than inorganic mercury. Among these cell lines, HGST-BR and TriG44 derived from marine sea turtles showed a significantly high tolerance to HgCl2 as compared to the three mammalian neural cells. Among these neural cells, SK-N-SH represented the most sensitive cells to both chemical forms of mercury.

  12. The local impact of a coal-fired power plant on inorganic mercury and methyl-mercury distribution in rice (Oryza sativa L.).

    PubMed

    Xu, Xiaohang; Meng, Bo; Zhang, Chao; Feng, Xinbin; Gu, Chunhao; Guo, Jianyang; Bishop, Kevin; Xu, Zhidong; Zhang, Sensen; Qiu, Guangle

    2017-04-01

    Emission from coal-fired power plants is one of the major anthropogenic sources of mercury (Hg) in the environment, because emitted Hg can be quickly deposited nearby the source, attention is paid to the effects of coal-burning facilities on levels of toxic methyl-mercury (MeHg) in biota near such sources. Since rice is an agricultural crop that can bio-accumulate MeHg, the potential effects of a large Hg-emitting coal-fired power plant in Hunan Province, China on both inorganic Hg (Hg(II)) and MeHg distributions in rice was investigated. Relatively high MeHg (up to 3.8 μg kg(-1)) and Hg(II) (up to 22 μg kg(-1)) concentrations were observed in rice samples collected adjacent to the plant, suggesting a potential impact of Hg emission from the coal fired power plant on the accumulation of Hg in rice in the area. Concentrations of MeHg in rice were positively correlated with soil MeHg, soil S, and gaseous elemental Hg (GEM) in ambient air. Soil MeHg was the most important factor controlling MeHg concentrations in rice. The methylation of Hg in soils may be controlled by factors such as the chemical speciation of inorganic Hg, soil S, and ambient GEM.

  13. Spectrophotometric determination of mercury in soils with triphenyltetrazolium chloride.

    PubMed

    Kamburova, M

    1993-05-01

    The formation of the acidocomplex of mercury(II) with triphenyl-tetrazolium chloride is studied spectrophotometrically in water-organic media. The composition of the complex is established as TTC:Hg:I = 1:1:1. The molar absorptivity (255) = (6.45 +/- 0.12) x 10(4) 1 mole(-1). cm(-1) is determined. The selectivity of the reaction is studied and the method for determination of mercury(II) 0.1-0.8 mug/ml is shown. Extraction investigations of the system discussed were carried out. The characteristic values for the extraction equilibrium and the equilibrium in the aqueous phase was determined: extraction constant K(ex) = 3.16 x 10(4), distribution constant K(D) = 20.67, and association constant = 1.53 x 10(3). 5 A rapid and sensitive extractive-photometric method for determination of mercury(II) in soil was developed. The determination was carried out without preliminary elimination of mercury.

  14. Mercury

    MedlinePlus

    Mercury is an element that is found in air, water and soil. It has several forms. Metallic mercury is a shiny, silver-white, odorless liquid. If ... with other elements to form powders or crystals. Mercury is in many products. Metallic mercury is used ...

  15. Determination of total mercury in biological and geological samples

    USGS Publications Warehouse

    Crock, James G.

    2005-01-01

    The analytical chemist is faced with several challenges when determining mercury in biological and geological materials. These challenges include widespread mercury contamination, both in the laboratory and the environment, possible losses of mercury during sample preparation and digestion, the wide range of mercury values commonly observed, ranging from the low nanogram per gram or per liter for background areas to hundreds of milligrams per kilogram in contaminated or ore-bearing areas, great matrix diversity, and sample heterogeneity1. These factors can be naturally occurring or anthropogenic, but must be addressed to provide a precise and accurate analysis. Although there are many instrumental methods available for the successful determination of mercury, no one technique will address all problems or all samples all of the time. The approach for the determination of mercury used at the U.S. Geological Survey, Crustal Imaging and Characterization Team, Denver Laboratories, utilizes a suite of complementary instrumental methods when approaching a study requiring mercury analyses. Typically, a study could require the analysis of waters, leachates or selective digestions of solids, vegetation, and biological materials such as tissue, bone, or shell, soils, rocks, sediments, coals, sludges, and(or) ashes. No one digestion or sample preparation method will be suitable for all of these matrices. The digestions typically employed at our laboratories include: (i) a closed-vessel microwave method using nitric acid and hydrogen peroxide, followed by digestion/dilution with a nitric acid/sodium dichromate solution, (ii) a robotic open test-tube digestion with nitric acid and sodium dichromate, (iii) a sealed Teflon? vessel with nitric acid and sodium dichromate, (iv) a sealed glass bottle with nitric acid and sodium dichromate, or (v) open test tube digestion with nitric and sulfuric acids and vanadium pentoxide. The common factor in all these digestions is that they are

  16. Experimental determination of cavitation thresholds in liquid water and mercury

    SciTech Connect

    Taleyarkhan, R.P.; West, C.D.; Moraga, F.

    1998-11-01

    An overview is provided on cavitation threshold measurement experiments for water and mercury. Various aspects to be considered that affect onset determination are discussed along with design specifications developed for construction of appropriate apparatus types. Both static and transient-cavitation effects were studied using radically different apparatus designs. Preliminary data are presented for cavitation thresholds for water and mercury over a range of temperatures in static and high-frequency environments. Implications and issues related to spallation neutron source target designs and operation are discussed.

  17. Docosahexaenoic acid counteracts attenuation of CD95-induced cell death by inorganic mercury.

    PubMed

    Gill, Randall; Lanni, Lydia; Jen, K-L Catherine; McCabe, Michael J; Rosenspire, Allen

    2015-01-01

    In the United States the principal environmental exposure to mercury is through dietary consumption of sea food. Although the mechanism by which low levels of mercury affect the nervous system is not well established, epidemiological studies suggest that low level exposure of pregnant women to dietary mercury can adversely impact cognitive development in their children, but that Docosahexaenoic acid (DHA), the most prominent n-polyunsaturated fatty acid (n-PUFA) present in fish may counteract negative effects of mercury on the nervous system. Aside from effects on the nervous system, epidemiological and animal studies have also suggested that low level mercury exposure may be a risk factor for autoimmune disease. However unlike the nervous system where a mechanism linking mercury to impaired cognitive development remains elusive, we have previously suggested a potential mechanism linking low level mercury exposures to immune system dysfunction and autoimmunity. In the immune system it is well established that disruption of CD95 mediated apoptosis leads to autoimmune disease. We have previously shown in vitro as well as in vivo that in lymphocytes burdened with low levels of mercury, CD95 mediated cell death is impaired. In this report we now show that DHA counteracts the negative effect of mercury on CD95 signaling in T lymphocytes. T cells which have been pre-exposed to DHA are able to cleave pro-caspase 3 and efficiently signal programmed cell death through the CD95 signaling pathway, whether or not they are burdened with low levels of mercury. Thus DHA may lower the risk of autoimmune disease after low level mercury exposures.

  18. Removal of inorganic mercury and methylmercury from surface waters following coagulation of dissolved organic matter with metal-based salts

    USGS Publications Warehouse

    Henneberry, Y.K.; Kraus, T.E.C.; Fleck, J.A.; Krabbenhoft, D.P.; Bachand, P.M.; Horwath, W.R.

    2011-01-01

    The presence of inorganic mercury (IHg) and methylmercury (MeHg) in surface waters is a health concern worldwide. This study assessed the removal potential use of metal-based coagulants as a means to remove both dissolved IHg and MeHg from natural waters and provides information regarding the importance of Hg associations with the dissolved organic matter (DOM) fraction and metal hydroxides. Previous research indicated coagulants were not effective at removing Hg from solution; however these studies used high concentrations of Hg and did not reflect naturally occurring concentrations of Hg. In this study, water collected from an agricultural drain in the Sacramento-San Joaquin Delta was filtered to isolate the dissolved organic matter (DOM) fraction. The DOM was then treated with a range of coagulant doses to determine the efficacy of removing all forms of Hg from solution. Three industrial-grade coagulants were tested: ferric chloride, ferric sulfate, and polyaluminum chloride. Coagulation removed up to 85% of DOM from solution. In the absence of DOM, all three coagulants released IHg into solution, however in the presence of DOM the coagulants removed up to 97% of IHg and 80% of MeHg. Results suggest that the removal of Hg is mediated by DOM-coagulant interactions. There was a preferential association of IHg with the more aromatic, higher molecular weight fraction of DOM but no such relationship was found for MeHg. This study offers new fundamental insights regarding large-scale removal of Hg at environmentally relevant regarding large-scale removal of Hg at environmentally relevant concentrations.

  19. Molecular mechanisms of plasmid-determined mercury and cadmium resistances in bacteria

    SciTech Connect

    Nucifora, G.

    1989-01-01

    The structural basis for induction of the broad spectrum mercurial resistance operon of pDU1358 with inorganic mercury and with phenylmercury acetate was addressed by DNA sequencing analysis (that showed that a major difference occurred in the 3{prime} 29 base pairs of the ital merR gene compared to the merR genes of Tn501 and R100) and by lac-fusion transcription experiments regulated by merR in trans. The lac-fusion results were compared with those from a narrow spectrum operon, and the pDU1358 merR deleted at the 3{prime} end. A hybrid mer operon containing the merR gene from pDU1358 and lacking the merB gene was inducible by both phenylmercury and inorganic Hg{sup 2+}, showing that organomercurial lyase is not needed for induction by organomercurials. A mutant form of pDU1358 merR missing the C-terminal 17 amino acids responded to inorganic Hg{sup 2+} but not to phenylmercury, indicating that the C-terminal region of the MerR protein of the pDU1358 mer operon is required for the recognition of phenylmercury acetate. The down regulation of the mer operon by the merD gene was also measured in trans with complementing mer operons of pDU1358 or R100 or merD{sup {minus}} mutants. In the presence of the merD gene, beta-galactosidase activity was lowered by 2 to 4 fold. The merD gene gene product was visualized by autoradiography. The Cd{sup 2+} resistance determinant cadA of S. aureus was investigated. The nucleotide sequence of the DNA fragment containing the cadA determinant revealed two open reading frames the larger one of which is essential for expression of cadmium resistance.

  20. Determination of total mercury in nuts at ultratrace level.

    PubMed

    da Silva, Maria José; Paim, Ana Paula S; Pimentel, Maria Fernanda; Cervera, M Luisa; de la Guardia, Miguel

    2014-08-01

    Total mercury, at μg kg(-1) level, was determined in different types of nuts (cashew nut, Brazil nuts, almond, pistachio, peanut, walnut) using a direct mercury analyser after previous sample defatting and by cold vapour atomic fluorescence spectrometry. There is not enough sensitivity in the second approach to determine Hg in previously digested samples due to the strong matrix effect. Mercury levels in 25 edible nut samples from Brazil and Spain were found in the range from 0.6 to 2.7μg kg(-1) by using the pyrolysis of sample after the extraction of the nut fat. The accuracy of the proposed method was confirmed by analysing certified reference materials of Coal Fly Ash-NIST SRM 1633b, Fucus-IAEA 140 and three unpolished Rice Flour NIES-10. The observed results were in good agreement with the certified values. The recoveries of different amounts of mercury added to nut samples ranged from 94 to 101%. RSD values corresponding to three measurements varied between 2.0 and 14% and the limit of detection and quantification of the method were 0.08 and 0.3μg kg(-1), respectively.

  1. Determination of mercurial species in fish by inductively coupled plasma mass spectrometry with anion exchange chromatographic separation.

    PubMed

    Chen, Xiaopan; Han, Chao; Cheng, Heyong; Liu, Jinhua; Xu, Zigang; Yin, Xuefeng

    2013-09-24

    This work demonstrated the feasibility of mercury speciation analysis by anion exchange chromatographic separation with inductively coupled plasma mass spectrometry detection. For the first time, by complexing with the mobile phase containing 3-mercapto-1-propanesulfonate into negatively charged complexes, fast separation of inorganic mercury (Hg(2+)), monomethylmercury (MeHg), ethylmercury (EtHg) and phenylmercury (PhHg) was achieved within 5 min on a 12.5-mm strong anion exchange column. The detection limits for Hg(2+), MeHg, EtHg and PhHg were 0.008, 0.024, 0.029 and 0.034 μg L(-1), respectively. The relative standard deviations of peak height and peak area (5.0 μg L(-1) for each Hg species) were all below 3%. The determined contents of Hg(2+), MeHg and total Hg in a certified reference material of fish tissue by the proposed method were in good accordance with the certified values with satisfactory recoveries. The relative errors for determining MeHg and total mercury were -2.4% and -1.2%, respectively, with an acceptable range for spike recoveries of 94-101%. Mercury speciation in 11 fish samples were then analyzed after the pretreated procedure. The mercury contents in all fish samples analyzed were found compliant with the criteria of the National Standards of China.

  2. Stress proteins and oxidative damage in a renal derived cell line exposed to inorganic mercury and lead.

    PubMed

    Stacchiotti, Alessandra; Morandini, Fausta; Bettoni, Francesca; Schena, Ilaria; Lavazza, Antonio; Grigolato, Pier Giovanni; Apostoli, Pietro; Rezzani, Rita; Aleo, Maria Francesca

    2009-10-29

    A close link between stress protein up-regulation and oxidative damage may provide a novel therapeutic tool to counteract nephrotoxicity induced by toxic metals in the human population, mainly in children, of industrialized countries. Here we analysed the time course of the expression of several heat shock proteins, glucose-regulated proteins and metallothioneins in a rat proximal tubular cell line (NRK-52E) exposed to subcytotoxic doses of inorganic mercury and lead. Concomitantly, we used morphological and biochemical methods to evaluate metal-induced cytotoxicity and oxidative damage. In particular, as biochemical indicators of oxidative stress we detected reactive oxygen species (ROS) and nitrogen species (RNS), total glutathione (GSH) and glutathione-S-transferase (GST) activity. Our results clearly demonstrated that mercury increases ROS and RNS levels and the expressions of Hsp25 and inducible Hsp72. These findings are corroborated by evident mitochondrial damage, apoptosis or necrosis. By contrast, lead is unable to up-regulate Hsp72 but enhances Grp78 and activates nuclear Hsp25 translocation. Furthermore, lead causes endoplasmic reticulum (ER) stress, vacuolation and nucleolar segregation. Lastly, both metals stimulate the over-expression of MTs, but with a different time course. In conclusion, in NRK-52E cell line the stress response is an early and metal-induced event that correlates well with the direct oxidative damage induced by mercury. Indeed, different chaperones are involved in the specific nephrotoxic mechanism of these environmental pollutants and work together for cell survival.

  3. Simultaneous determination of mercury and organic carbon using a direct mercury analyzer: Mercury profiles in sediment cores from oxbow lakes in the Mississippi Delta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sediment cores from seasonal wetland and open water areas from six oxbow lakes in the Mississippi River alluvial flood plain were analyzed for total-mercury (Hg) using a direct mercury analyzer (DMA). In the process we evaluated the feasibility of simultaneously determining organic matter content by...

  4. Determination of the rotation of Mercury from satellite gravimetry

    NASA Astrophysics Data System (ADS)

    Cicalò, S.; Milani, A.

    2012-11-01

    Space missions can have as a goal the determination of the interior structure of a planet: this is the case for the ESA BepiColombo mission to Mercury. Very precise range and range-rate tracking from the Earth and onboard accelerometry will provide a huge amount of data, from which it will be possible to study the gravity field of Mercury and other parameters of interest. Gravity can be used to constrain the interior structure, but cannot uniquely determine the interior mass distribution. A much stronger constraint on the interior can be given by also determining the rotation state of the planet. If the planet is asymmetric enough, the gravity field as measured by an orbiting probe tracked from the Earth contains signatures from the rotation. Are these enough to solve for the rotation state, to the required accuracy, from tracking data alone, without measurements of the surface? In order to reach some result analytically, a simplified analytical model is developed, and the symmetry breaking, occurring when the shape of the planet deviates from spherical symmetry, is characterized by explicit formulae. Moreover, a full cycle numerical simulation of the Radio Science Experiment is performed, including the generation of simulated tracking and accelerometer data and the determination, by least-squares fit, of the Mercury-centric initial conditions of the probe, of Mercury's gravity field and its rotation state, together with other parameters affecting the dynamics. The conclusion is that there is no reason of principle prohibiting the determination of the rotation from gravimetry, and the sensitivity of the measurements and the coverage are good enough to perform the experiment at the required level of accuracy. This will be important also in ensuring independent terms of comparison for the rotation experiment performed with a high-resolution camera. The mission is currently under development and much care has to be taken in guaranteeing the scientific goals even if

  5. Low-Dose Inorganic Mercury Increases Severity and Frequency of Chronic Coxsackievirus-Induced Autoimmune Myocarditis in Mice

    PubMed Central

    Nyland, Jennifer F.; Fairweather, DeLisa; Shirley, Devon L.; Davis, Sarah E.; Rose, Noel R.; Silbergeld, Ellen K.

    2012-01-01

    Mercury is a widespread environmental contaminant with neurotoxic impacts that have been observed over a range of exposures. In addition, there is increasing evidence that inorganic mercury (iHg) and organic mercury (including methyl mercury) have a range of immunotoxic effects, including immune suppression and induction of autoimmunity. In this study, we investigated the effect of iHg on a model of autoimmune heart disease in mice induced by infection with coxsackievirus B3 (CVB3). We examined the role of timing of iHg exposure on disease; in some experiments, mice were pretreated with iHg (200 μg/kg, every other day for 15 days) before disease induction with virus inoculation, and in others, they were treated with iHg after the acute (viral) phase of disease but before the development of dilated cardiomyopathy (DCM). iHg alone had no effect on heart pathology. Pretreatment with iHg before CVB3 infection significantly increased the severity of chronic myocarditis and DCM compared with control animals receiving vehicle alone. In contrast, treatment with iHg after acute myocarditis did not affect the severity of chronic disease. The increased chronic myocarditis, fibrosis, and DCM induced by iHg pretreatment were not due to increased viral replication in the heart, which was unaltered by iHg treatment. iHg pretreatment induced a macrophage infiltrate and mixed cytokine response in the heart during acute myocarditis, including significantly increased interleukin (IL)-12, IL-17, interferon-γ, and tumor necrosis factor-α levels. IL-17 levels were also significantly increased in the spleen during chronic disease. Thus, we show for the first time that low-dose Hg exposure increases chronic myocarditis and DCM in a murine model. PMID:21984480

  6. Inorganic mercury causes pancreatic beta-cell death via the oxidative stress-induced apoptotic and necrotic pathways

    SciTech Connect

    Chen Yawen; Huang Chunfa; Yang Chingyao; Yen Chengchieh; Tsai Kehsung; Liu Shinghwa

    2010-03-15

    Mercury is a well-known highly toxic metal. In this study, we characterize and investigate the cytotoxicity and its possible mechanisms of inorganic mercury in pancreatic beta-cells. Mercury chloride (HgCl{sub 2}) dose-dependently decreased the function of insulin secretion and cell viability in pancreatic beta-cell-derived HIT-T15 cells and isolated mouse pancreatic islets. HgCl{sub 2} significantly increased ROS formation in HIT-T15 cells. Antioxidant N-acetylcysteine effectively reversed HgCl{sub 2}-induced insulin secretion dysfunction in HIT-T15 cells and isolated mouse pancreatic islets. Moreover, HgCl{sub 2} increased sub-G1 hypodiploids and annexin-V binding in HIT-T15 cells, indicating that HgCl{sub 2} possessed ability in apoptosis induction. HgCl{sub 2} also displayed several features of mitochondria-dependent apoptotic signals including disruption of the mitochondrial membrane potential, increase of mitochondrial cytochrome c release and activations of poly (ADP-ribose) polymerase (PARP) and caspase 3. Exposure of HIT-T15 cells to HgCl{sub 2} could significantly increase both apoptotic and necrotic cell populations by acridine orange/ethidium bromide dual staining. Meanwhile, HgCl{sub 2} could also trigger the depletion of intracellular ATP levels and increase the LDH release from HIT-T15 cells. These HgCl{sub 2}-induced cell death-related signals could be significantly reversed by N-acetylcysteine. The intracellular mercury levels were markedly elevated in HgCl{sub 2}-treated HIT-T15 cells. Taken together, these results suggest that HgCl{sub 2}-induced oxidative stress causes pancreatic beta-cell dysfunction and cytotoxicity involved the co-existence of apoptotic and necrotic cell death.

  7. Behavioural and biochemical alterations in Penaeus monodon post-larvae diet-exposed to inorganic mercury.

    PubMed

    Harayashiki, Cyntia Ayumi Yokota; Reichelt-Brushett, Amanda J; Liu, Lei; Butcher, Paul

    2016-12-01

    Mercury is a metal naturally present in the environment with concentrations in aquatic systems increasing annually due to human activities. This represents a great concern mainly due to its high toxicity to organisms and consequences for human health. Most studies regarding the toxic effect of mercury have focussed on freshwater species using water as the exposure and uptake pathway. In contrast, the present study investigated the effects of dietary exposure of mercury to the marine crustacean Penaeus monodon post-larvae during 96 h to evaluate changes in behaviour (swimming activity and risk taken) and in biochemical biomarkers [acetylcholinesterase (AChE) and glutathione S-transferase (GST)]. Results showed a decrease in swimming activity with an increase in mercury exposure, but no changes were observed regarding the behavioural response 'risk taken'. Prawns from medium (0.56 μg g(-1)) and high (1.18 μg g(-1)) treatments had their GST activity reduced in relation to the beginning of experiment (time 0), while AChE activity was increased in the low (0.15 μg g(-1)) treatment in relation to time 0. In the present study, behaviour analysis were clearer than biochemical biomarkers and results might indicate P. monodon populations from a mercury contaminated environment might be at risk, since the behavioural alterations observed increases the risk of predation.

  8. Comparison of Adsorbed Mercury Screening Method With Cold-Vapor Atomic Absorption Spectrophotometry for Determination of Mercury in Soil

    NASA Technical Reports Server (NTRS)

    Easterling, Donald F.; Hovanitz, Edward S.; Street, Kenneth W.

    2000-01-01

    A field screening method for the determination of elemental mercury in environmental soil samples involves the thermal desorption of the mercury from the sample onto gold and then the thermal desorption from the gold to a gold-film mercury vapor analyzer. This field screening method contains a large number of conditions that could be optimized for the various types of soils encountered. In this study, the conditions were optimized for the determination of mercury in silty clay materials, and the results were comparable to the cold-vapor atomic absorption spectrophotometric method of determination. This paper discusses the benefits and disadvantages of employing the field screening method and provides the sequence of conditions that must be optimized to employ this method of determination on other soil types.

  9. Mercury in terrestrial biomass and soils and factors determining atmospheric mercury sequestration

    NASA Astrophysics Data System (ADS)

    Obrist, D.; Johnson, D. W.; Lindberg, S.; Luo, Y.

    2008-12-01

    Terrestrial carbon (C) pools play an important role in uptake, deposition, sequestration, and emission of atmospheric mercury (Hg). The objective of this study is to assess atmospheric Hg sequestration associated with vegetation and soil C pools in forest ecosystems. As part of an ongoing EPA STAR project, we are systematically evaluating Hg pools and fluxes associated with terrestrial C pools in all major ecosystem compartments (i.e., leaves, branches, bole, litter, soils) across selected US forest ecosystems. Results from the first five sites located in the remote western United States show that the dominant above-ground pool of mercury is associated with surface litter with smaller pools associated with leaves and branches. Mass concentrations greatly increase in the following order: green leaves, dry leaves, initial litter, partially decomposed litter, humus. Based on detailed comparison of stochiometric relationships (e.g., Hg/C and Hg/N ratios) we conclude that these concentration increases are dominated by additional atmospheric deposition retained in the decomposing plant material while exposed to the environment rather than by organic C losses during decomposition. The large majority of total ecosystem mercury, up to 98 percent, however, is sequestered belowground in the soils. Soil Hg accumulation across all sites is greatly determined by the availability of organic matter in these systems, with soil C and soil N explaining more than 90 percent of the variability in observed soil Hg stocks. Our results suggest that the availability of soil organic matter is the main determinant for retention of atmospheric inputs in soils and hence in terrestrial ecosystems. Ecosystem structure and soil organic accumulation hence determine the resilience of Hg in terrestrial ecosystems with important implication for the stability and runoff of atmospheric Hg deposition to surrounding waterbodies.

  10. Isotopic Methods for Determining the Relative Importance of Bioavailability Versus Trophic Position in Controlling Mercury Concentrations in Everglades Mosquitofish

    NASA Astrophysics Data System (ADS)

    Bemis, B. E.; Kendall, C.

    2007-12-01

    The concentration of mercury in fish tissues is widely used as an indicator of the magnitude of mercury contamination in aquatic ecosystems. Eastern mosquitofish (Gambusia holbrookii) is an important sentinel species used for this purpose in the varied environments of the Florida Everglades, because mosquitofish are abundant, have a short lifespan, and migrate little. Like other freshwater fish, the primary route of mercury uptake into mosquitofish tissues is through diet as bioavailable methylmercury. Yet, it is unclear whether variations in mosquitofish mercury observed across the Everglades are due primarily to differences in bioaccumulation (i.e., trophic position) or abundance of methylmercury available to the food web base. We use isotopic methods to investigate the importance of these two controls on mosquitofish mercury at the landscape scale. As part of the USEPA REMAP project, mosquitofish and periphyton were collected during September 1996 from over one hundred sites throughout the Everglades and analyzed for mercury concentration. The USGS analyzed splits of the samples for nitrogen (d15N), carbon (d13C), and sulfur (d34S) isotopic composition, to investigate the causes of mercury variations. The d15N value of tissues is often used to estimate the relative trophic positions of organisms in a food web, and should correlate positively with tissue mercury if bioaccumulation is an important control on mosquitofish mercury concentration. The d13C value can be useful for detecting differences in food web base (e.g., algal versus detrital), and thus the entry point of contaminants. Tissue d34S potentially indicates the extent of dissimilatory sulfate reduction in sediments, a process used by sulfate-reducing bacteria (SRB) during conversion of inorganic Hg(II) to bioavailable methylmercury. Because this process increases the d34S value of remaining sulfate, which enters the food web base, mosquitofish sulfur isotopes should show positive correlations with SRB

  11. Naked-eye sensor for rapid determination of mercury ion.

    PubMed

    Liu, Jing; Wu, Dapeng; Yan, Xiaohui; Guan, Yafeng

    2013-11-15

    A naked-eye paper sensor for rapid determination of trace mercury ion in water samples was designed and demonstrated. The mercury-sensing rhodamine B thiolactone was immobilized in silica matrices and the silica matrices were impregnated firmly and uniformly in the filter paper. As water samples flow through the filter paper, the membrane color will change from white to purple red, which could be observed obviously with naked eye, when concentration of mercury ions equals to or exceeds 10nM, the maximum residue level in drinking water recommended by U.S. EPA. The color change can also be recorded by a flatbed scanner and then digitized, reducing the detection limit of Hg(2+) down to 1.2 nM. Moreover, this method is extremely specific for Hg(2+) and shows a high tolerance ratio of interferent coexisting ions. The presence of Na(+) (2 mM), K(+) (2 mM), Fe(3+) (0.1 mM), Zn(2+) (0.1 mM), Mg(2+) (0.1 mM), Ni(2+) (50 μM), Co(2+) (50 μM), Cd(2+) (50 μM), Pb(2+) (50 μM), Cu(2+) (50 μM) and Ag(+) (3.5 μM) did not interfere with the detection of Hg(2+) (25 nM). Finally, the present method was applied in the detection of Hg(2+) in mineral water, tap water and pond water.

  12. Population-Based Inorganic Mercury Biomonitoring and the Identification of Skin Care Products as a Source of Exposure in New York City

    PubMed Central

    McKelvey, Wendy; Jeffery, Nancy; Clark, Nancy; Kass, Daniel; Parsons, Patrick J.

    2011-01-01

    Background Mercury is a toxic metal that has been used for centuries as a constituent of medicines and other items. Objective We assessed exposure to inorganic mercury in the adult population of New York City (NYC). Methods We measured mercury concentrations in spot urine specimens from a representative sample of 1,840 adult New Yorkers in the 2004 NYC Health and Nutrition Examination Survey. Cases with urine concentrations ≥ 20 μg/L were followed up with a telephone or in-person interview that asked about potential sources of exposure, including ritualistic/cultural practices, skin care products, mercury spills, herbal medicine products, and fish. Results Geometric mean urine mercury concentration in NYC was higher for Caribbean-born blacks [1.39 μg/L; 95% confidence interval (CI), 1.14–1.70] and Dominicans (1.04 μg/L; 95% CI, 0.82–1.33) than for non-Hispanic whites (0.67 μg/L; 95% CI, 0.60–0.75) or other racial/ethnic groups. It was also higher among those who reported at least 20 fish meals in the past 30 days (1.02 μg/L; 95% CI, 0.83–1.25) than among those who reported no fish meals (0.50 μg/L; 95% CI, 0.41–0.61). We observed the highest 95th percentile of exposure (21.18 μg/L; 95% CI, 7.25–51.29) among Dominican women. Mercury-containing skin-lightening creams were a source of exposure among those most highly exposed, and we subsequently identified 12 imported products containing illegal levels of mercury in NYC stores. Conclusion Population-based biomonitoring identified a previously unrecognized source of exposure to inorganic mercury among NYC residents. In response, the NYC Health Department embargoed products and notified store owners and the public that skin-lightening creams and other skin care products that contain mercury are dangerous and illegal. Although exposure to inorganic mercury is not a widespread problem in NYC, users of these products may be at risk of health effects from exposure. PMID:20923743

  13. Determination of Mercury Exposure among Dental Health Workers in Nakhon Si Thammarat Province, Thailand

    PubMed Central

    Decharat, Somsiri; Phethuayluk, Piriyaluk; Maneelok, Supandee; Thepaksorn, Phayong

    2014-01-01

    Objectives. The main objective of this study was to assess the mercury exposure levels in dental health workers that work in dental clinics. The study evaluated the airborne and urinary mercury levels, the type of work done in the clinic, and the effect of mercury exposure on health of dental health workers. Material and Methods. A case-control study was conducted with 124 exposed and 124 matched nonexposed subjects. Personal and area samplings were conducted to quantify mercury concentrations by solid sorbent tube. Urine samples were collected to determine mercury levels by cold-vapor atomic absorption spectrometer mercury analyzer. Results and Discussion. 17.6% (n = 32/182) of the air samples were higher than the occupational exposure limit (OEL). A multiple regression model was constructed. Significant predictors of urinary mercury levels included dietary consumption (fish or seafood), duration of work (yrs), work position, personal protection equipment used (PPE), and personal hygiene behaviors. Significant correlations were observed between mercury levels in urine and mercury in storage areas (r = 0.499, P < 0.05) and between mercury levels in urine and airborne mercury in personal samplings (r = 0.878, P < 0.001). Conclusion. Improvements in working conditions, occupational health training, and PPE use are recommended to reduce mercury exposure. PMID:25349606

  14. Embryotoxic response produced by inorganic mercury in different strains of hamsters

    SciTech Connect

    Gale, T.F.

    1981-02-01

    This report compares the mercury-induced embryotoxicity among one noninbred and five inbred strains of hamsters. A single dose of mercuric acetate was injected into pregnant hamsters on the morning of the 8th gestation day. Treated and control animals were killed on either the 12th or 15th gestation day and studied for the types and frequency of external and internal abnormalities as well as the incidence of resorption sites. The hamster strains exhibited significant resorption rates as well as a variety of abnormalities including edema, retardation, ventral wall defects, pericardial cavity distention, cleft palate, hydrocephalus, and heart defects. Significant but varied interstrain differences were observed for most of these indicators of mercury-induced embryotoxicity. The results of this study were compared with prior work in which the same hamster strains were exposed to cadmium or lead.

  15. Evaluation of a sequential extraction process used for determining mercury binding mechanisms to coal combustion byproducts.

    PubMed

    Noel, James D; Biswas, Pratim; Giammar, Daniel E

    2007-07-01

    Leaching of mercury from coal combustion byproducts is a concern because of the toxicity of mercury. Leachability of mercury can be assessed by using sequential extraction procedures. Sequential extraction procedures are commonly used to determine the speciation and mobility of trace metals in solid samples and are designed to differentiate among metals bound by different mechanisms and to different solid phases. This study evaluated the selectivity and effectiveness of a sequential extraction process used to determine mercury binding mechanisms to various materials. A six-step sequential extraction process was applied to laboratory-synthesized materials with known mercury concentrations and binding mechanisms. These materials were calcite, hematite, goethite, and titanium dioxide. Fly ash from a full-scale power plant was also investigated. The concentrations of mercury were measured using inductively coupled plasma (ICP) mass spectrometry, whereas the major elements were measured by ICP atomic emission spectrometry. The materials were characterized by X-ray powder diffraction and scanning electron microscopy with energy dispersive spectroscopy. The sequential extraction procedure provided information about the solid phases with which mercury was associated in the solid sample. The procedure effectively extracted mercury from the target phases. The procedure was generally selective in extracting mercury. However, some steps in the procedure extracted mercury from nontarget phases, and others resulted in mercury redistribution. Iron from hematite and goethite was only leached in the reducible and residual extraction steps. Some mercury associated with goethite was extracted in the ion exchangeable step, whereas mercury associated with hematite was extracted almost entirely in the residual step. Calcium in calcite and mercury associated with calcite were primarily removed in the acid-soluble extraction step. Titanium in titanium dioxide and mercury adsorbed onto

  16. Non-chromatographic mercury speciation and determination in wine by new core-shell ion-imprinted sorbents.

    PubMed

    Dakova, Ivanka; Yordanova, Tanya; Karadjova, Irina

    2012-09-15

    In this study new Hg(II) core-shell imprinted sorbents (Hg(II)-IIPs) were prepared and tested for speciation and determination of Hg in wine. The silica gel, chemically modified with 3-(trimethoxysilyl)propyl methacrylate (TSPM) was used as supporting material. The Hg(II)-imprinted polymer layer was grafted by copolymerization of methacrylic acid and trimethylolpropane trimethacrylate in the presence of Hg(II) complexes with two different chelating agents: 1-pyrrolidinedithiocarboxylic acid (P(PDC-Hg)/SiG) and 1-(2-thiazolylazo)-2-naphthol (P(TAN-Hg)/SiG). High selectivity and fast kinetics of processes of sorption and desorption for Hg(II) were found by using P(PDC-Hg)/SiG. Recovery experiments performed for selective determination of inorganic mercury in wines showed that the interfering organic matrix did not influence the extraction efficiency. Column solid phase extraction scheme was developed for the determination and speciation of Hg in wines. The limit of detection (LOD) achieved for inorganic mercury determination in wine samples is 0.02 μg L(-1) (3σ), measured by CV AAS. The relative standard deviation varied in the range 6-11% at 0.05-2 μg L(-1) Hg levels. The sorbents showed high mechanical and chemical stability and extraction efficiency has not changed after more than 50 sorption/desorption cycles.

  17. Fabrication of a selective mercury sensor based on the adsorption of cold vapor of mercury on carbon nanotubes: determination of mercury in industrial wastewater.

    PubMed

    Safavi, Afsaneh; Maleki, Norouz; Doroodmand, Mohammad Mahdi

    2010-01-15

    A new sensor for the determination of mercury at microg ml(-1) levels is proposed based on the adsorption of mercury vapor on single-walled carbon nanotubes (SWCNTs). The changes in the impedance of SWCNTs were monitored upon adsorption of mercury vapor. The adsorption behaviour of mercury on SWCNTs was compared with that on multi-walled carbon nanotubes (MWCNTs) and carbon nanofibers (CNFs). Cold vapor of mercury was generated at 65 degrees C using Sn(II) solution as a reducing agent. The limit of detection was 0.64 microg ml(-1) for Hg(II) species. The calibration curve for Hg(II) was linear from 1.0 to 30.0 microg ml(-1). The relative standard deviation (RSD) of eight replicate analyses of 15 microg ml(-1) of Hg(II) was 2.7%. The results showed no interfering effects from many foreign species and hydride forming elements. The system was successfully applied to the determination of the mercury content of different types of wastewater samples.

  18. Effects of substituted dithiocarbamates on distribution and excretion of inorganic mercury in mice

    SciTech Connect

    Gale, G.R.; Atkins, L.M.; Smith, A.B.; Jones, M.M.

    1985-02-01

    Diethyldithiocarbamate (DDTC) and six of its N,N-disubstituted congeners were evaluated for their relative efficacies in mobilizing and promoting excretion of mercury (Hg/sup + +/) using mice which had been given /sup 203/Hg/sup + +/; D-penicillamine (PEN) was used as a positive control compound. While none was as effective as PEN when compared on a molar dose basis, significant activity as assessed by reduction of whole body /sup 203/Hg burden, was observed following treatment with three of the analogs. The order of effectiveness was PEN greater than N-methyl-N-dithiocarboxyglucamine (MDCG) greater than di(carboxymethyl)dithiocarbamate (DCDC) greater than di(hydroxyethyl)dithiocarbamate (DHDC).

  19. High-Throughput Determination of Mercury in Tobacco and Mainstream Smoke from Little Cigars.

    PubMed

    Fresquez, Mark R; Gonzalez-Jimenez, Nathalie; Gray, Naudia; Watson, Clifford H; Pappas, R Steven

    2015-09-01

    A method was developed that utilizes a platinum trap for mercury from mainstream tobacco smoke, which represents an improvement over traditional approaches that require impingers and long sample preparation procedures. In this approach, the trapped mercury is directly released for analysis by heating the trap in a direct mercury analyzer. The method was applied to the analysis of mercury in the mainstream smoke of little cigars. The mercury levels in little cigar smoke obtained under Health Canada Intense smoking machine conditions ranged from 7.1 × 10(-3) to 1.2 × 10(-2) mg/m(3). These air mercury levels exceed the chronic inhalation minimal risk level corrected for intermittent exposure to metallic mercury (e.g., 1 or 2 h per day, 5 days per week) determined by the Agency for Toxic Substances and Disease Registry. Multivariate statistical analysis was used to assess associations between mercury levels and little cigar physical design properties. Filter ventilation was identified as the principal physical parameter influencing mercury concentrations in mainstream little cigar smoke generated under ISO machine smoking conditions. With filter ventilation blocked under Health Canada Intense smoking conditions, mercury concentrations in tobacco and puff number (smoke volume) were the primary physical parameters that influenced mainstream smoke mercury concentrations.

  20. High Throughput Determination of Mercury in Tobacco and Mainstream Smoke from Little Cigars

    PubMed Central

    Fresquez, Mark R.; Gonzalez-Jimenez, Nathalie; Gray, Naudia; Watson, Clifford H.; Pappas, R. Steven

    2015-01-01

    A method was developed that utilizes a platinum trap for mercury from mainstream tobacco smoke which represents an improvement over traditional approaches that require impingers and long sample preparation procedures. In this approach, the trapped mercury is directly released for analysis by heating the trap in a direct mercury analyzer. The method was applied to the analysis of mercury in the mainstream smoke of little cigars. The mercury levels in little cigar smoke obtained under Health Canada Intense smoking machine conditions ranged from 7.1 × 10−3 mg/m3 to 1.2 × 10−2 mg/m3. These air mercury levels exceed the chronic inhalation Minimal Risk Level corrected for intermittent exposure to metallic mercury (e.g., 1 or 2 hours per day, 5 days per week) determined by the Agency for Toxic Substances and Disease Registry. Multivariate statistical analysis was used to assess associations between mercury levels and little cigar physical design properties. Filter ventilation was identified as the principal physical parameter influencing mercury concentrations in mainstream little cigar smoke generated under ISO machine smoking conditions. With filter ventilation blocked under Health Canada Intense smoking conditions, mercury concentrations in tobacco and puff number (smoke volume) were the primary physical parameters that influenced mainstream smoke mercury concentrations. PMID:26051388

  1. Determination of mercury in fish samples by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Liaw, Ming-Jyh; Jiang, Shiuh-Jen; Li, Yi-Ching

    1997-06-01

    Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to the determination of mercury in several fish samples. The effects of instrument operating conditions and slurry preparation on the ion signals are reported. Palladium was used as modifier to delay the vaporization of mercury in this study. As the vaporization behavior of mercury in fish slurry and aqueous solution is quite different, the standard addition method was used for the determination of mercury in reference materials. The detection limit of mercury estimated from the standard addition curve was in the range 0.002-0.004 μg g -1 for different samples. This method has been applied to the determination of mercury in dogfish muscle reference material (DORM-1 and DORM-2) and dogfish liver reference material (DOLT-1). Accuracy was better than 4% and precision was better than 7% with the USS-ETV-ICP-MS method.

  2. Renal mechanisms in the cardiovascular effects of chronic exposure to inorganic mercury in rats.

    PubMed Central

    Carmignani, M; Boscolo, P; Artese, L; Del Rosso, G; Porcelli, G; Felaco, M; Volpe, A R; Giuliano, G

    1992-01-01

    Male weanling Wistar rats received 200 micrograms/ml of mercury (Hg), as HgCl2, in drinking water for 180 days. At the end of the treatment, systemic arterial blood pressure was augmented, cardiac inotropism was reduced, and heart rate was unchanged. Light and electron microscopical studies of the kidney showed a mesangial proliferative glomerulonephritis in about 80% of the glomeruli. Tubular cells showed reduction of the acid phosphatase activity, which was related to functional abnormalities of the lysosomes. In the 24 hour urine samples of the Hg exposed rats, there was slight reduction of kallikrein activity, but evident proteinuria was not present in all samples. Plasma renin activity was reduced, that of angiotensin I-converting enzyme was augmented, and plasma aldosterone concentrations were unchanged. Mercury was accumulated mostly in the kidney of the Hg treated animals; and the content of Hg in the heart was higher than in the brain. These data show that chronic exposure to Hg acts on the kidney with complex mechanisms of toxicity; these contribute to modify systemic haemodynamics. Images PMID:1571292

  3. Mercury and halogens in coal--Their role in determining mercury emissions from coal combustion

    USGS Publications Warehouse

    Kolker, Allan; Quick, Jeffrey C.; Senior, Connie L.; Belkin, Harvey E.

    2012-01-01

    Mercury is a toxic pollutant. In its elemental form, gaseous mercury has a long residence time in the atmosphere, up to a year, allowing it to be transported long distances from emission sources. Mercury can be emitted from natural sources such as volcanoes, or from anthropogenic sources, such as coal-fired powerplants. In addition, all sources of mercury on the Earth's surface can re-emit it from land and sea back to the atmosphere, from which it is then redeposited. Mercury in the atmosphere is present in such low concentrations that it is not considered harmful. Once mercury enters the aquatic environment, however, it can undergo a series of biochemical transformations that convert a portion of the mercury originally present to methylmercury, a highly toxic organic form of mercury that accumulates in fish and birds. Many factors contribute to creation of methylmercury in aquatic ecosystems, including mercury availability, sediment and nutrient load, bacterial influence, and chemical conditions. In the United States, consumption of fish with high levels of methylmercury is the most common pathway for human exposure to mercury, leading the U.S. Environmental Protection Agency (EPA) to issue fish consumption advisories in every State. The EPA estimates that 50 percent of the mercury entering the atmosphere in the United States is emitted from coal-burning utility powerplants. An EPA rule, known as MATS (for Mercury and Air Toxics Standards), to reduce emissions of mercury and other toxic pollutants from powerplants, was signed in December 2011. The rule, which is currently under review, specifies limits for mercury and other toxic elements, such as arsenic, chromium, and nickel. MATS also places limits on emission of harmful acid gases, such as hydrochloric acid and hydrofluoric acid. These standards are the result of a 2010 detailed nationwide program by the EPA to sample stack emissions and thousands of shipments of coal to coal-burning powerplants. The United

  4. [Mercury poisoning].

    PubMed

    Bensefa-Colas, L; Andujar, P; Descatha, A

    2011-07-01

    Mercury is a widespread heavy metal with potential severe impacts on human health. Exposure conditions to mercury and profile of toxicity among humans depend on the chemical forms of the mercury: elemental or metallic mercury, inorganic or organic mercury compounds. This article aims to reviewing and synthesizing the main knowledge of the mercury toxicity and its organic compounds that clinicians should know. Acute inhalation of metallic or inorganic mercury vapours mainly induces pulmonary diseases, whereas chronic inhalation rather induces neurological or renal disorders (encephalopathy and interstitial or glomerular nephritis). Methylmercury poisonings from intoxicated food occurred among some populations resulting in neurological disorders and developmental troubles for children exposed in utero. Treatment using chelating agents is recommended in case of symptomatic acute mercury intoxication; sometimes it improves the clinical effects of chronic mercury poisoning. Although it is currently rare to encounter situations of severe intoxication, efforts remain necessary to decrease the mercury concentration in the environment and to reduce risk on human health due to low level exposure (dental amalgam, fish contamination by organic mercury compounds…). In case of occupational exposure to mercury and its compounds, some disorders could be compensated in France. Clinicians should work with toxicologists for the diagnosis and treatment of mercury intoxication.

  5. Recent Developments in the Speciation and Determination of Mercury Using Various Analytical Techniques

    PubMed Central

    Suvarapu, Lakshmi Narayana; Baek, Sung-Ok

    2015-01-01

    This paper reviews the speciation and determination of mercury by various analytical techniques such as atomic absorption spectrometry, voltammetry, inductively coupled plasma techniques, spectrophotometry, spectrofluorometry, high performance liquid chromatography, and gas chromatography. Approximately 126 research papers on the speciation and determination of mercury by various analytical techniques published in international journals since 2013 are reviewed. PMID:26236539

  6. Simultaneous determination of arsenic and mercury species in rice by ion-pairing reversed phase chromatography with inductively coupled plasma mass spectrometry.

    PubMed

    Fang, Yong; Pan, Yushi; Li, Peng; Xue, Mei; Pei, Fei; Yang, Wenjian; Ma, Ning; Hu, Qiuhui

    2016-12-15

    An analytical method using reversed phase chromatography-inductively coupled plasma mass spectrometry for arsenic and mercury speciation analysis was described. The effect of ion-pairing reagent on simultaneous separation of four arsenic (arsenite, arsenate, monomethlyarsonate and dimethylarsinate) and three mercury species (inorganic mercury (Hg(II)), methylmecury and ethylmercury) was investigated. Parameters including concentrations and pH of the mobile phase were optimized. The separation and re-equilibration time was attained within 20min. Meanwhile, a sequential extraction method for arsenic and mercury in rice was tested. Subsequently, 1% HNO3 microwave-assisted extraction was chosen. Calibration curves based on peak area measurements were linear with correlation coefficient greater than 0.9958 for each species in the range studied. The detection limits of the species were in the range of 0.84-2.41μg/L for arsenic and 0.01-0.04μg/L for mercury, respectively. The proposed method was then successfully applied for the simultaneous determination of arsenic and mercury species in rice flour standard material and two kinds of rice from local markets.

  7. A recommended protocol for the preservation and storage of ';reactive' inorganic mercury in sediment

    NASA Astrophysics Data System (ADS)

    Stumpner, E. B.; Marvin-DiPasquale, M. C.; Alpers, C. N.; Fleck, J.

    2013-12-01

    Stannous-chloride-reducible divalent mercury, or ';reactive' mercury (Hg(II)R), is a methodologically defined Hg fraction that is increasingly being used as a surrogate measure of the Hg pool available for microbial Hg(II)-methylation. A critical examination of Hg(II)R stability was conducted in a set of experiments that examined techniques of sediment preservation and storage over time (1, 7, 30, 90, and 180 days), temperature (-80°C, -20°C, and 5°C), and with/without a glove bag that excluded atmospheric oxygen. A second set of experiments examined effects of homogenization and thaw time. On the basis of experimental results, a recommended protocol is presented here for studies where Hg(II)R is a targeted analyte. Recommendations include: (1) thorough sediment homogenization and sub-sampling for analysis of Hg(II)R, iron species, and total reduced sulfur inside of an oxygen-free glove bag, (2) refrigeration (5°C) storage after homogenization, and (3) completion of the Hg(II)R assay within 2 to 7 days after homogenization. Sediment for the experiments was chosen from four distinct Hg-contaminated sites surrounding the Sacramento-San Joaquin Delta and San Francisco Bay. Sites were chosen based on legacy Hg contamination in the form of cinnabar (HgS) from past Hg mining (Alviso Slough and Cache Creek sites), and elemental Hg from past gold mining (Cosumnes River and Humbug Creek (South Yuba River watershed) sites). Samples were chosen with a wide range of organic content, redox conditions, and total reduced sulfur concentration because these properties are known to influence Hg(II)R concentration. Geochemical modeling conducted with PHREEQC indicated that the oxidation of aqueous sulfide plays an important role in controlling the saturation index of cinnabar, which has a direct effect on the solubility of Hg(II), and by extension an influence on the sediment Hg(II)R assay.

  8. Distribution of inorganic mercury in Sacramento River water and suspended colloidal sediment material

    USGS Publications Warehouse

    Roth, D.A.; Taylor, H.E.; Domagalski, J.; Dileanis, P.; Peart, D.B.; Antweiler, R.C.; Alpers, C.N.

    2001-01-01

    The concentration and distribution of inorganic Hg was measured using cold-vapor atomic fluorescence spectrometry in samples collected at selected sites on the Sacramento River from below Shasta Dam to Freeport, CA, at six separate times between 1996 and 1997. Dissolved (ultrafiltered, 0.005 ??m equivalent pore size) Hg concentrations remained relatively constant throughout the system, ranging from the detection limit (< 0.4 ng/L) to 2.4 ng/L. Total Hg (dissolved plus colloidal suspended sediment) concentrations ranged from the detection limit at the site below Shasta Dam in September 1996 to 81 ng/L at the Colusa site in January 1997, demonstrating that colloidal sediment plays an important role in the downriver Hg transport. Sequential extractions of colloid concentrates indicate that the greatest amount of Hg associated with sediment Was found in the "residual" (mineral) phase with a significant quantity also occurring in the "oxidizable" phase. Only a minor amount of Hg was observed in the "reducible" phase. Dissolved Hg loads remained constant or increased slightly in the downstream direction through the study area, whereas the total inorganic Hg load increased significantly downstream especially in the reach of the fiver between Bend Bridge and Colusa. Analysis of temporal variations showed that Hg loading was positively correlated to discharge.

  9. MRP2 and the DMPS- and DMSA-mediated elimination of mercury in TR(-) and control rats exposed to thiol S-conjugates of inorganic mercury.

    PubMed

    Bridges, Christy C; Joshee, Lucy; Zalups, Rudolfs K

    2008-09-01

    Cysteine (Cys) and homocysteine (Hcy)-S-conjugates of inorganic mercury (Hg2+) are transportable species of Hg2+ that are taken up readily by proximal tubular cells. The metal chelators, 2,3-dimercaptopropane-1-sulfonic acid (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA), have been used successfully to extract Hg2+ from these cells, presumably via the multidrug resistance protein (Mrp2). In the current study, we tested the hypothesis that Mrp2 is involved in the DMPS- and DMSA-mediated extraction of Hg2+ following administration of Hg2+ as an S-conjugate of Cys or Hcy. To test this hypothesis, control and TR(-) (Mrp2-deficient) rats were injected with 0.5 micromol/kg HgCl2 (containing 203Hg2+) conjugated to 1.25 micromol/kg Cys or Hcy. After 24 and 28 h, rats were treated with saline or 100 mg/kg DMPS or DMSA. Tissues were harvested 48 h after Hg2+ exposure. The renal and hepatic burden of Hg2+ was greater in saline-injected TR- rats than in corresponding controls. Accordingly, the content of Hg2+ in the urine and feces was less in TR- rats than in controls. Following treatment with DMPS or DMSA, the renal content of Hg2+ in both groups of rats was reduced significantly and the urinary excretion of Hg2+ was increased. In liver, the effect of each chelator appeared to be dependent upon the form in which Hg2+ was administered. In vitro experiments provide direct evidence indicating that DMPS and DMSA-S-conjugates of Hg2+ are substrates for Mrp2. Overall, these data support our hypothesis that Mrp2 is involved in the DMPS and DMSA-mediated extraction of the body burden of Hg2+.

  10. Effective mercury(II) bioremoval from aqueous solution, and its electrochemical determination.

    PubMed

    Balderas-Hernández, Patricia; Roa-Morales, Gabriela; Ramírez-Silva, María Teresa; Romero-Romo, Mario; Rodríguez-Sevilla, Erika; Esparza-Schulz, Juan Marcos; Juárez-Gómez, Jorge

    2017-01-01

    This work proposed mercury elimination using agricultural waste (Allium Cepa L.). The biomass removed 99.4% of mercury, following a pseudo-second order kinetics (r(2) = 0.9999). The Langmuir model was adequately fitted to the adsorption isotherm, thereby obtaining the maximum mercury adsorption capacity of 111.1 ± 0.3 mg g(-1). The biomass showed high density of strong mercury chelating groups, thus making it economically attractive. Also, the implementation of a mercury-selective electrode for continuous determination in real time is proposed; this electrode replaces techniques like atomic absorption spectroscopy, thus it can be applied to real time studies. This work therefore presents a new perspective for removing mercury(II) from contaminated water for environmental remediation.

  11. Determination of mercury in fish otoliths by cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS)†

    PubMed Central

    Kenduzler, Erdal; Ates, Mehmet; Arslan, Zikri; McHenry, Melanie; Tchounwou, Paul B.

    2012-01-01

    A method based on cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS) has been developed for determination of inorganic mercury, Hg(II), and total mercury in fish otoliths. Sodium borohydride (NaBH4) was used as the only reducing agent and its concentration was optimized across an acidity gradient to selectively reduce Hg(II) without affecting methylmercury, CH3Hg(I). Inorganic Hg was quantitatively reduced to elemental mercury (Hg0) with 1×10−4% (m/v) NaBH4. CH3Hg(I) required a minimum of 0.5% (m/v) NaBH4 for complete reduction. Increasing the HCl concentration of solution to 5% (v/v) improved the selectivity toward Hg(II) as it decreased the signals from CH3Hg(I) to baseline levels. Potassium ferricyanide solution was the most effective in eliminating the memory effects of Hg compared with a number of chelating and oxidizing agents, including EDTA, gold chloride, thiourea, cerium ammonium nitrate and 2-mercaptoethylamine chloride. The relative standard deviation (RSD) was less than 5% for 1.0 μg L−1 Hg(II) solution. The detection limits were 4.2 and 6.4 ng L−1 (ppt) for Hg(II) and total Hg, respectively. Sample dissolution conditions and recoveries were examined with ultra-pure CaCO3 (99.99%) spiked with Hg(II) and CH3HgCl. Methylmercury was stable when dissolution was performed with up to 20% (v/v) HCl at 100 oC. Recoveries from spiked solutions were higher than 95% for both Hg(II) and CH3Hg(I). The method was applied to the determination of Hg(II) and total Hg concentrations in the otoliths of red emperor (CRM 22) and Pacific halibut. Total Hg concentration in the otoliths was 0.038 ± 0.004 μg g−1 for the red emperor and 0.021 ± 0.003 μg g−1 for the Pacific halibut. Inorganic Hg accounted for about 25% of total Hg indicating that Hg in the otoliths was predominantly organic mercury (e.g., methylmercury). However, as opposed to the bioaccumulation in tissues, methylmercury levels in otoliths was very low suggesting a

  12. Determination of mercury distribution inside spent compact fluorescent lamps by atomic absorption spectrometry.

    PubMed

    Rey-Raap, Natalia; Gallardo, Antonio

    2012-05-01

    In this study, spent compact fluorescent lamps were characterized to determine the distribution of mercury. The procedure used in this research allowed mercury to be extracted in the vapor phase, from the phosphor powder, and the glass matrix. Mercury concentration in the three phases was determined by the method known as cold vapor atomic absorption spectrometry. Median values obtained in the study showed that a compact fluorescent lamp contained 24.52±0.4ppb of mercury in the vapor phase, 204.16±8.9ppb of mercury in the phosphor powder, and 18.74±0.5ppb of mercury in the glass matrix. There are differences in mercury concentration between the lamps since the year of manufacture or the hours of operation affect both mercury content and its distribution. The 85.76% of the mercury introduced into a compact fluorescent lamp becomes a component of the phosphor powder, while more than 13.66% is diffused through the glass matrix. By washing and eliminating all phosphor powder attached to the glass surface it is possible to classified the glass as a non-hazardous waste.

  13. DEVELOPMENT AND CHARACTERIZATION OF AN ANNULAR DENUDER METHODOLOGY FOR THE MEASUREMENT OF DIVALENT INORGANIC REACTIVE GASEOUS MERCURY IN AMBIENT AIR

    EPA Science Inventory

    Atmospheric mercury is predominantly present in the gaseous elemental form (Hg0). However, anthropogenic emissions (e.g. incineration, fossil fuel combustion) emit and natural processes create particulate-phase mercury (Hg(p)) and divalent reactive gas-phase mercury (RGM). RG...

  14. Determination of mercury compounds in fish by microwave-assisted extraction and liquid chromatography-vapor generation-inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Chiou, Chwei-Sheng; Jiang, Shiuh-Jen; Kumar Danadurai, K. Suresh

    2001-07-01

    A method employing a vapor generation system and LC combined with inductively coupled plasma mass spectrometry (LC-ICP-MS) is presented for the determination of mercury in biological tissues. An open vessel microwave digestion system was used to extract the mercury compounds from the sample matrix. The efficiency of the mobile phase, a mixture of L-cysteine and 2-mercaptoethanol, was evaluated for LC separation of inorganic mercury [Hg(II)], methylmercury (methyl-Hg) and ethylmercury (ethyl-Hg). The sensitivity, detection limits and repeatability of the liquid chromatography (LC) ICP-MS system with a vapor generator were comparable to, or better than, that of an LC-ICP-MS system with conventional pneumatic nebulization, or other sample introduction techniques. The experimental detection limits for various mercury species were in the range of 0.05-0.09 ng ml -1 Hg, based on peak height. The proposed method was successfully applied to the determination of mercury compounds in a swordfish sample purchased from the local market. The accuracy of the method was evaluated by analyzing a marine biological certified reference material (DORM-2, NRCC).

  15. Some sources and sinks of monomethyl and inorganic mercury on Ellesmere Island in the Canadian High Arctic.

    PubMed

    St Louis, Vincent L; Sharp, Martin J; Steffen, Alexandra; May, Al; Barker, Joel; Kirk, Jane L; Kelly, David J A; Arnott, Shelley E; Keatley, Bronwyn; Smol, John P

    2005-04-15

    We identified some of the sources and sinks of monomethyl mercury (MMHg) and inorganic mercury (HgII) on Ellesmere Island in the Canadian High Arctic. Atmospheric Hg depletion events resulted in the deposition of Hg(II) into the upper layers of snowpacks, where concentrations of total Hg (all forms of Hg) reached over 20 ng/L. However, our data suggest that much of this deposited Hg(II) was rapidly photoreduced to Hg(0) which then evaded back to the atmosphere. As a result, we estimate that net wet and dry deposition of Hg(II) during winter was lower at our sites (0.4-5.9 mg/ha) than wet deposition in more southerly locations in Canada and the United States. We also found quite high concentrations of monomethyl Hg (MMHg) in snowpacks (up to 0.28 ng/L), and at times, most of the Hg in snowpacks was present as MMHg. On the Prince of Wales Icefield nearthe North Water Polynya, we observed a significant correlation between concentrations of Cl and MMHg in snow deposited in the spring, suggesting a marine source of MMHg. We hypothesize that dimethyl Hg fluxes from the ocean to the atmosphere through polynyas and open leads in ice, and is rapidly photolyzed to MMHgCl. We also found that concentrations of MMHg in initial snowmelt on John Evans Glacier (up to 0.24 ng/L) were higher than concentrations of MMHg in the snowpack (up to 0.11 ng/L), likely due to either sublimation of snow or preferential leaching of MMHg from snow during the initial melt phase. This springtime pulse of MMHg to the High Arctic, in conjunction with climate warming and the thinning and melting of sea ice, may be partially responsible for the increase in concentrations of Hg observed in certain Arctic marine mammals in recent decades. Concentrations of MMHg in warm and shallow freshwater ponds on Ellesmere Island were also quite high (up to 3.0 ng/L), leading us to conclude that there are very active regions of microbial Hg(II) methylation in freshwater systems during the short summer season in the

  16. Mercury

    NASA Technical Reports Server (NTRS)

    Gault, D. E.; Burns, J. A.; Cassen, P.; Strom, R. G.

    1977-01-01

    Prior to the flight of the Mariner 10 spacecraft, Mercury was the least investigated and most poorly known terrestrial planet (Kuiper 1970, Devine 1972). Observational difficulties caused by its proximity to the Sun as viewed from Earth caused the planet to remain a small, vague disk exhibiting little surface contrast or details, an object for which only three major facts were known: 1. its bulk density is similar to that of Venus and Earth, much greater than that of Mars and the Moon; 2. its surface reflects electromagnetic radiation at all wavelengths in the same manner as the Moon (taking into account differences in their solar distances); and 3. its rotation period is in 2/3 resonance with its orbital period. Images obtained during the flyby by Mariner 10 on 29 March 1974 (and the two subsequent flybys on 21 September 1974 and 16 March 1975) revealed Mercury's surface in detail equivalent to that available for the Moon during the early 1960's from Earth-based telescopic views. Additionally, however, information was obtained on the planet's mass and size, atmospheric composition and density, charged-particle environment, and infrared thermal radiation from the surface, and most significantly of all, the existence of a planetary magnetic field that is probably intrinsic to Mercury was established. In the following, this new information is summarized together with results from theoretical studies and ground-based observations. In the quantum jumps of knowledge that have been characteristic of "space-age" exploration, the previously obscure body of Mercury has suddenly come into sharp focus. It is very likely a differentiated body, probably contains a large Earth-like iron-rich core, and displays a surface remarkably similar to that of the Moon, which suggests a similar evolutionary history.

  17. Modeling Mercury in Proteins

    SciTech Connect

    Smith, Jeremy C; Parks, Jerry M

    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.

  18. Toxicity of heavy metals: 1. Correlation of metal toxicity with in vitro calmodulin inhibition. 2. Interactions of inorganic mercury with red blood cells: Control vs. amyotrophic lateral sclerosis

    SciTech Connect

    Henson, J.L.C.

    1989-01-01

    The toxic effects of metals are examined in two separate in vitro systems. In the first system, the correlation between published mouse LD{sub 50} values and experimentally derived values for calmodulin inhibition was determined. Calmodulin activity was defined as stimulated phosphodiesterase (PDE) activity. The basal PDE activity was determined with each cation and was unaffected by any of the concentrations utilized. The IC{sub 50} was determined from a plot of the log of the cation concentration vs. stimulated PDE activity for each cation. A very strong correlation was obtained when the IC{sub 50} vs. mouse LD{sub 50} curve was examined (p < 0.001). Calmodulin regulates many enzyme systems and processes that affect or are affected by calcium. This study was examined in light of the possible role of calcium in cell damage and death. In the second study, the interactions of erythrocytes (RBCs) and inorganic mercury (Hg) were examined. A broad range of Hg concentrations were utilized to explore the nature of the interactions. Two different mechanisms of RBC Hg accumulation and retention were evident. At lower Hg concentrations (0.001-0.1 {mu}M), the RBC accumulation/retention of Hg was constant (52% of available Hg), reversible, and temperature sensitive. At higher concentrations (1-100 {mu}M), the accumulation increased with Hg concentration, was not reversible, and was not temperature sensitive. A relationship between Hg and amyotrophic lateral sclerosis (ALS) is suggested by several reports in the literature. The accumulation/ retention of Hg by RBCs from control and ALS patients were compared. The RBCs from ALS patients released far more Hg during a two hr incubation 37C at 10 and 100 {mu}M Hg compared to controls.

  19. Interactive toxicity of inorganic mercury and trichloroethylene in rat and human proximal tubules: Effects on apoptosis, necrosis, and glutathione status

    SciTech Connect

    Lash, Lawrence H. . E-mail: l.h.lash@wayne.edu; Putt, David A.; Hueni, Sarah E.; Payton, Scott G.; Zwickl, Joshua

    2007-06-15

    Simultaneous or prior exposure to one chemical may alter the concurrent or subsequent response to another chemical, often in unexpected ways. This is particularly true when the two chemicals share common mechanisms of action. The present study uses the paradigm of prior exposure to study the interactive toxicity between inorganic mercury (Hg{sup 2+}) and trichloroethylene (TRI) or its metabolite S-(1,2-dichlorovinyl)-L-cysteine (DCVC) in rat and human proximal tubule. Pretreatment of rats with a subtoxic dose of Hg{sup 2+} increased expression of glutathione S-transferase-{alpha}1 (GST{alpha}1) but decreased expression of GST{alpha}2, increased activities of several GSH-dependent enzymes, and increased GSH conjugation of TRI. Primary cultures of rat proximal tubular (rPT) cells exhibited both necrosis and apoptosis after incubation with Hg{sup 2+}. Pretreatment of human proximal tubular (hPT) cells with Hg{sup 2+} caused little or no changes in GST expression or activities of GSH-dependent enzymes, decreased apoptosis induced by TRI or DCVC, but increased necrosis induced by DCVC. In contrast, pretreatment of hPT cells with TRI or DCVC protected from Hg{sup 2+} by decreasing necrosis and increasing apoptosis. Thus, whereas pretreatment of hPT cells with Hg{sup 2+} exacerbated cellular injury due to TRI or DCVC by shifting the response from apoptosis to necrosis, pretreatment of hPT cells with either TRI or DCVC protected from Hg{sup 2+}-induced cytotoxicity by shifting the response from necrosis to apoptosis. These results demonstrate that by altering processes related to GSH status, susceptibilities of rPT and hPT cells to acute injury from Hg{sup 2+}, TRI, or DCVC are markedly altered by prior exposures.

  20. Mercury's Surface Magnetic Field Determined from Proton-Reflection Magnetometry

    NASA Technical Reports Server (NTRS)

    Winslow, Reka M.; Johnson, Catherine L.; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Lillis, Robert J.; Korth, Haje; Slavin, James A.; Solomon, Sean C.; Zurbuchen, Thomas H.; Zuber, Maria T.

    2014-01-01

    Solar wind protons observed by the MESSENGER spacecraft in orbit about Mercury exhibit signatures of precipitation loss to Mercury's surface. We apply proton-reflection magnetometry to sense Mercury's surface magnetic field intensity in the planet's northern and southern hemispheres. The results are consistent with a dipole field offset to the north and show that the technique may be used to resolve regional-scale fields at the surface. The proton loss cones indicate persistent ion precipitation to the surface in the northern magnetospheric cusp region and in the southern hemisphere at low nightside latitudes. The latter observation implies that most of the surface in Mercury's southern hemisphere is continuously bombarded by plasma, in contrast with the premise that the global magnetic field largely protects the planetary surface from the solar wind.

  1. Determination of total mercury in sorbent tubes using direct mercury analysis

    SciTech Connect

    Nortje, J.

    2008-08-15

    A U.S. EPA draft method, Method 30 B, has been approved as a reference method for relative accuracy testing audits of Continuous Emissions Monitoring Systems (CEMS) and sorbent trap monitoring systems installed at coal-fired utilities. It is also appropriate for mercury emissions testing at such facilities. This method is a procedure for measuring total vapor phase mercury emissions from coal-fired combustion sources using all extractive or thermal analytical technique and UV atomic absorption (AA) or UV atomic fluorescence (AF) cold vapor analyzers as the analytical system. The DMA-80 direct mercury analyzer uses thermal decomposition and ultimately AA spectrophotometry to analyze samples. The analyzer can be used for Method 30 B analysis.

  2. A simple extraction procedure for determination of total mercury in crude oil.

    PubMed

    Uddin, Razi; Al-Fahad, Mossaed A; Al-Rashwan, Ayman K; Al-Qarni, Mohammad A

    2013-05-01

    The determination of mercury in crude oil and petroleum products is particularly difficult due to the volatile nature of both mercury and the matrix, which may lead to significant loss of the analyte. A simple extraction method for total mercury has been developed to determine total mercury in crude oil using cold vapor atomic fluorescence spectrometry. The homogenized crude oil sample was diluted to 5, 10, and 20 % (w/w) in toluene. The diluted crude oil samples were spiked with 10 and 40 μg/kg (w/w). The samples were extracted using an oxidant/acid solution, BrCl/HCl. The mercury was extracted into the aqueous phase; the ionic mercury was then reduced to volatile elemental mercury (Hg(0)) by stannous chloride (SnCl2). The mercury vapor was detected by Merlin cold vapor atomic fluorescence spectrometry at a 253.7-nm wavelength. The average recoveries for mercury in spiked diluted crude oil (10 and 40 μg/kg, w/w) were between 96 and 103 %, respectively, in 5 and 10 % spiked diluted crude oil. Whereas, low recoveries (<50 %) were recorded in 20 % diluted spiked crude oil. The method detection limit was calculated as t (0.01)(n - 1) × SD where t is the student's value for 99 % confidence level and standard deviation estimate with n - 1 degrees of freedom. The method detection limit was found to be 0.38 μg/kg based on 5 g of diluted crude oil sample. The method is sensitive enough to determine low levels of mercury in crude oil.

  3. Species-specific isotope tracers to study the accumulation and biotransformation of mixtures of inorganic and methyl mercury by the microalga Chlamydomonas reinhardtii.

    PubMed

    Bravo, Andrea Garcia; Le Faucheur, Séverine; Monperrus, Mathilde; Amouroux, David; Slaveykova, Vera I

    2014-09-01

    The present study demonstrates that species-specific isotope tracing is an useful tool to precisely measure Hg accumulation and transformations capabilities of living organisms at concentrations naturally encountered in the environment. To that end, a phytoplanktonic green alga Chlamydomonas reinhardtii Dangeard (Chlamydomonadales, Chlorophyceae) was exposed to mixtures of (199)-isotopically enriched inorganic mercury ((199)IHg) and of (201)-isotopically enriched monomethylmercury ((201)CH3Hg) at a concentration range between less than 1 pM to 4 nM. Additionally, one exposure concentration of both mercury species was also studied separately to evaluate possible interactive effects. No difference in the intracellular contents was observed for algae exposed to (199)IHg and (201)CH3Hg alone or in their mixture, suggesting similar accumulation capacity for both species at the studied concentrations. Demethylation of (201)CH3Hg was observed at the highest exposure concentrations, whereas no methylation was detected.

  4. Longitudinal study of methylmercury and inorganic mercury in blood and urine of pregnant and lactating women, as well as in umbilical cord blood.

    PubMed

    Vahter, M; Akesson, A; Lind, B; Björs, U; Schütz, A; Berglund, M

    2000-10-01

    We have investigated exposure to methylmercury (MeHg) and mercury vapor (Hg0) in pregnant women and their newborns in Stockholm. The women were followed for 15 months post delivery. MeHg, inorganic Hg (I-Hg), and total Hg (T-Hg) in maternal and cord blood were determined by automated alkaline solubilization/reduction and cold vapor atomic fluorescence spectrometry. T-Hg in urine was determined by inductively coupled plasma mass spectrometry. About 72% of the Hg in blood (n = 148) in early pregnancy was MeHg (median 0.94 microg/L, maximum 6.8 microg/L). Blood MeHg decreased during pregnancy, partly due to decreased intake of fish in accordance with recommendations to not eat certain predatory fish during pregnancy. Cord blood MeHg (median 1.4 microg/L, maximum 4.8 microg/L) was almost twice that in maternal blood in late pregnancy and was probably influenced by maternal MeHg exposure earlier and before pregnancy. Blood I-Hg (median 0.37 microg/L, maximum 4.2 microg/L) and urine T-Hg (median 1.6 microg/L, maximum 12 microg/L) in early pregnancy were highly correlated, and both were associated with the number of amalgam fillings. The concentrations decreased during lactation, probably due to excretion in milk. Cord blood I-Hg was correlated with that in maternal blood. The results show the importance of speciation of Hg in blood for evaluation of exposure and health risks.

  5. EPA Method 245.1: Determination of Mercury in Water by Cold Vapor Atomic Absorption Spectrometry

    EPA Pesticide Factsheets

    SAM lists this method for preparation and analysis of aqueous liquid and drinking water samples. This method will determine mercuric chloride and methoxyethylmercuric acetate as total mercury using cold vapor atomic absorption spectrometry.

  6. Determination of mercury distribution inside spent compact fluorescent lamps by atomic absorption spectrometry

    SciTech Connect

    Rey-Raap, Natalia

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer New treatments for CFL are required considering the aim of Directive 202/96/CE. Black-Right-Pointing-Pointer It is shown that most of the mercury introduced into a CFL is in the phosphor powder. Black-Right-Pointing-Pointer Experimental conditions for microwave-assisted sample digestion followed by AAS measurements are described. Black-Right-Pointing-Pointer By washing the glass it is possible to reduce the concentration below legal limits. - Abstract: In this study, spent compact fluorescent lamps were characterized to determine the distribution of mercury. The procedure used in this research allowed mercury to be extracted in the vapor phase, from the phosphor powder, and the glass matrix. Mercury concentration in the three phases was determined by the method known as cold vapor atomic absorption spectrometry. Median values obtained in the study showed that a compact fluorescent lamp contained 24.52 {+-} 0.4 ppb of mercury in the vapor phase, 204.16 {+-} 8.9 ppb of mercury in the phosphor powder, and 18.74 {+-} 0.5 ppb of mercury in the glass matrix. There are differences in mercury concentration between the lamps since the year of manufacture or the hours of operation affect both mercury content and its distribution. The 85.76% of the mercury introduced into a compact fluorescent lamp becomes a component of the phosphor powder, while more than 13.66% is diffused through the glass matrix. By washing and eliminating all phosphor powder attached to the glass surface it is possible to classified the glass as a non-hazardous waste.

  7. The bioaccessibility of soil-based mercury as determined by physiological based extraction tests and human biomonitoring in children.

    PubMed

    Safruk, Adam M; Berger, Robert G; Jackson, Blair J; Pinsent, Celine; Hair, Alan T; Sigal, Elliot A

    2015-06-15

    Environmental contaminants associated with soil particles are generally less bioavailable than contaminants associated with other exposure media where chemicals are often found in more soluble forms. In vitro methods, such as Physiological Based Extraction Tests (PBET), can provide estimates of bioaccessibility for soil-based contaminants. The results of these tests can be used to predict exposure to contaminants from soil ingestion pathways within human health risk assessment (HHRA). In the current investigation, an HHRA was conducted to examine the risks associated with elevated concentrations of mercury in soils in the northern Canadian smelter community of Flin Flon, Manitoba. A PBET was completed for residential soils and indicated mean bioaccessibilities of 1.2% and 3.0% for total mercury using gastric phase and gastric+intestinal phase methodologies, respectively. However, as many regulators only allow for the consideration of in vitro results for lead and arsenic in the HHRA process, in vitro bioaccessibility results for mercury were not utilized in the current HHRA. Based on the need to assume 100% bioaccessibility for inorganic mercury in soil, results from the HHRA indicated the need for further assessment of exposure and risk. A biomonitoring study was undertaken for children between 2 and 15 years of age in the community to examine urinary inorganic mercury concentrations. Overall, 375 children provided valid urine samples for analysis. Approximately 50% of urine samples had concentrations of urinary inorganic mercury below the limit of detection (0.1 μg/L), with an average creatinine adjusted concentration of 0.11 μg/g. Despite high variability in mercury soil concentrations within sub-communities, soil concentrations did not appear to influence urinary mercury concentrations. The results of the current investigation indicate that mercury bioaccessibility in residential soils in the Flin Flon area was likely limited and that HHRA estimates would

  8. Comparative study of hotplate wet digestion methods for the determination of mercury in biosolids.

    PubMed

    Lomonte, Cristina; Gregory, David; Baker, Alan J M; Kolev, Spas D

    2008-08-01

    The re-use of biosolids is becoming increasingly popular for land applications. However, biosolids may contain elevated levels of metals and metalloids (including mercury) relative to background environmental concentrations. Consequently, reliable mercury analysis is important to allow classification of biosolids and to determine appropriate options for beneficial uses. This paper reports on a comparative study of 12 hotplate wet digestion methods for their suitability for the determination of mercury in biosolids. The methods were applied to mercury biosolids samples from four localities of two different sewage treatment plants in the State of Victoria, Australia. Samples were also spiked with methylmercury chloride and mercury sulphide to evaluate the Hg recovery in each hotplate digestion method. Aqua regia (HCl:HNO(3)=3:1), reverse aqua regia (HCl:HNO(3)=1:3), nitric, hydrochloric, sulphuric acid and their combinations with or without hydrogen peroxide were studied as wet digestion solutions. The method providing the best mercury recoveries was optimized. Under optimal conditions the corresponding analytical procedure consisted of 1h pre-digestion of 0.4 g biosolids sample with 10 ml reverse aqua regia with temperature increasing to 110 degrees C and 3h digestion at this temperature. In the last 10 min of the digestion step, 2 ml hydrogen peroxide were added to ensure complete decomposition of all mercury containing compounds. After filtering and dilution with deionised water (1:10), the concentration of mercury was determined by cold vapour atomic absorption spectrometry. It is expected, that the wet acid digestion method developed in this study will be also applicable to biosolids from other sewage treatment plants and to other types of solid mercury samples with elevated levels of organic matter.

  9. Determination of mercury in phosphate fertilizers by cold vapor atomic absorption spectrometry.

    PubMed

    de Jesus, Robson M; Silva, Laiana O B; Castro, Jacira T; de Azevedo Neto, Andre D; de Jesus, Raildo M; Ferreira, Sergio L C

    2013-03-15

    In this paper, a method for the determination of mercury in phosphate fertilizers using slurry sampling and cold vapor atomic absorption spectrometry (CV QT AAS) is proposed. Because mercury (II) ions form strong complexes with phosphor compounds, the formation of metallic mercury vapor requires the presence of lanthanum chloride as a release agent. Thiourea increases the amount of mercury that is extracted from the solid sample to the liquid phase of the slurry. The method is established using two steps. First, the slurry is prepared using the sample, lanthanum chloride, hydrochloric acid solution and thiourea solution and is sonicated for 20 min. Afterward, mercury vapor is generated using an aliquot of the slurry in the presence of the hydrochloric acid solution and isoamylic alcohol with sodium tetrahydroborate solution as the reducing agent. The experimental conditions for slurry preparation were optimized using two-level full factorial design involving the factors: thiourea and lanthanum chloride concentrations and the duration of sonication. The method allows the determination of mercury by external calibration using aqueous standards with limits of detection and quantification of 2.4 and 8.2 μg kg(-1), respectively, and precision, expressed as relative standard deviation, of 6.36 and 5.81% for two phosphate fertilizer samples with mercury concentrations of 0.24 and 0.57 mg kg(-1), respectively. The accuracy was confirmed by the analysis of a certified reference material of phosphate fertilizer that was provided by the National Institute of Standards & Technology (NIST). The method was applied to determine mercury in six commercial samples of phosphate fertilizers. The mercury content varied from 33.97 to 209.28 μg kg(-1). These samples were also analyzed employing inductively coupled plasma mass spectrometry (ICP-MS). The ICP-MS results were consistent with the results from our proposed method.

  10. Superoxide anion radical (O2(-)) degrades methylmercury to inorganic mercury in human astrocytoma cell line (CCF-STTG1).

    PubMed

    Mailloux, Ryan J; Yumvihoze, Emmanuel; Chan, Hing Man

    2015-09-05

    Methylmercury (MeHg) is a global pollutant that is affecting the health of millions of people worldwide. However, the mechanism of MeHg toxicity still remains somewhat elusive and there is no treatment. It has been known for some time that MeHg can be progressively converted to inorganic mercury (iHg) in various tissues including the brain. Recent work has suggested that cleavage of the carbon-metal bond in MeHg in a biological environment is facilitated by reactive oxygen species (ROS). However, the oxyradical species that actually mediates this process has not been identified. Here, we provide evidence that superoxide anion radical (O2(-)) can convert MeHg to iHg. The calculated second-order rate constant for the degradation of 1μM MeHg by O2(-) generated by xanthine/xanthine oxidase was calculated to be 2×10(5)M(-1)s(-1). We were also able to show that this bioconversion can proceed in intact CCF-STTG1 human astrocytoma cells exposed to paraquat (PQ), a O2(-) generating viologen. Notably, exposure of cells to increasing amounts of PQ led to a dose dependent increase in both MeHg and iHg. Indeed, a 24h exposure to 500μM PQ induced a ∼13-fold and ∼18-fold increase in intracellular MeHg and iHg respectively. These effects were inhibited by superoxide dismutase mimetic MnTBAP. In addition, we also observed that a 24h exposure to a biologically relevant concentration of MeHg (1μM) did not induce cell death, oxidative stress, or even changes in cellular O2(-) and H2O2. However, co-exposure to PQ enhanced MeHg toxicity which was associated with a robust increase in cell death and oxidative stress. Collectively our results show that O2(-) can bioconvert MeHg to iHg in vitro and in intact cells exposed to conditions that simulate high intracellular O2(-) production. In addition, we show for the first time that O2(-) mediated degradation of MeHg to iHg enhances the toxicity of MeHg by facilitating an accumulation of both MeHg and iHg in the intracellular

  11. Versatile combustion-amalgamation technique for the photometric determination of mercury in fish and environmental samples

    USGS Publications Warehouse

    Willford, Wayne A.; Hesselberg, Robert J.; Bergman, Harold L.

    1973-01-01

    Total mercury in a variety of substances is determined rapidly and precisely by direct sample combustion, collection of released mercury by amalgamation, and photometric measurement of mercury volatilized from the heated amalgam. Up to 0.2 g fish tissue is heated in a stream of O2 (1.2 L/min) for 3.5 min in 1 tube of a 2-tube induction furnace. The released mercury vapor and combustion products are carried by the stream of O2 through a series of traps (6% NaOH scrubber, water condenser, and Mg(CIO4)2 drying tube) and the mercury is collected in a 10 mm diameter column of 24 gauge gold wire (8 g) cut into 3 mm lengths. The resulting amalgam is heated in the second tube of the induction furnace and the volatilized mercury is measured with a mercury vapor meter equipped with a recorder-integrator. Total analysis time is approximately 8 min/sample. The detection limit is less than 0.002 μg and the system is easily converted for use with other biological materials, water, and sediments.

  12. Study on the determination of trace methyl mercury in seawater by gas chromatography

    NASA Astrophysics Data System (ADS)

    Wang, Zhongzhu; Cui, Xianzhou

    1990-03-01

    Sample seawater containing trace methyl mercury was acidified and adsorbed on hydrosulfo-cotton, washed with hydrochloric acid, extracted by benzene and dried, and then determined by a gas chromatograph with electron capture detector. This method, which can detect a minimum concentration of 0.1×10-10%, can be used to monitor the 10-10% content of methyl mercury in seawater.

  13. A simulation study of inorganic sulfur cycling in the water level fluctuation zone of the Three Gorges Reservoir, China and the implications for mercury methylation.

    PubMed

    Liu, Jiang; Jiang, Tao; Huang, Rong; Wang, Dingyong; Zhang, Jinzhong; Qian, Sheng; Yin, Deliang; Chen, Hong

    2017-01-01

    The water level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) in China experiences a drying and wetting rotation every year, and the water level induced redox variation may influence inorganic sulfur speciation and mercury methylation. In this work, a simulative flooding and drying experiment and a sulfate added flooding experiment were conducted to study this topic. The results showed that sulfate was reduced from the 10th d during the flooding period based on the detected sulfide in water and the increased elemental sulfur (S(0)) in sediment. Sulfate reduction and sulfide re-oxidation led to the increase of S(0) contents with the maximal values of 1.86 and 0.46 mg kg(-1) during the flooding and drying period, respectively. Methylmercury (MeHg) content in sediment displayed a rising trend (0.16-0.28 μg kg(-1)) in the first 40 d during the flooding period, and then declined from 0.28 to 0.15 μg kg(-1). A positive correlation between MeHg content and S(0) content in soil (r = 0.53, p < 0.05) was found during the flooding period, and a positive but not significant correlation between the percent of MeHg in THg (%MeHg) and S(0) content (r = 0.85, p = 0.08). In sulfate added flooding simulation, MeHg content in sediment did not increase with the sulfate concentration increasing. The increased pyrite in high-sulfate treatment may fix mercury through adsorption process. This study demonstrated that inorganic sulfur species especially S(0) and chromium reducible sulfur (CRS) play an important role on mercury methylation in the WLFZ of the TGR.

  14. Ion time-of-flight determinations of doubly to singly ionized mercury ion ratios from a mercury electron bombardment discharge

    NASA Technical Reports Server (NTRS)

    Sellen, J. M., Jr.; Kemp, R. F.; Hall, D. F.

    1973-01-01

    Doubly to singly charged mercury ion ratios in electron bombardment ion thruster exhaust beams have been determined as functions of bombardment discharge potential, thrust beam current, thrust beam radial position, acceleration-deceleration voltage ratio, and propellant utilization fraction. A mathematical model for two-step ionization processes has been derived, and calculated ion ratios are compared to observed ratios. Production of Hg(++) appears to result primarily from sequential ionization of Hg(+) in the discharge. Experimental and analytical results are presented, and design, construction, and operation features of an electrostatic deflection ion time-of-flight analyzer for the determination of the above-mentioned ratios are reviewed.

  15. Mercury in the nation's streams - Levels, trends, and implications

    USGS Publications Warehouse

    Wentz, Dennis A.; Brigham, Mark E.; Chasar, Lia C.; Lutz, Michelle A.; Krabbenhoft, David P.

    2014-01-01

    Mercury is a potent neurotoxin that accumulates in fish to levels of concern for human health and the health of fish-eating wildlife. Mercury contamination of fish is the primary reason for issuing fish consumption advisories, which exist in every State in the Nation. Much of the mercury originates from combustion of coal and can travel long distances in the atmosphere before being deposited. This can result in mercury-contaminated fish in areas with no obvious source of mercury pollution.Three key factors determine the level of mercury contamination in fish - the amount of inorganic mercury available to an ecosystem, the conversion of inorganic mercury to methylmercury, and the bioaccumulation of methylmercury through the food web. Inorganic mercury originates from both natural sources (such as volcanoes, geologic deposits of mercury, geothermal springs, and volatilization from the ocean) and anthropogenic sources (such as coal combustion, mining, and use of mercury in products and industrial processes). Humans have doubled the amount of inorganic mercury in the global atmosphere since pre-industrial times, with substantially greater increases occurring at locations closer to major urban areas.In aquatic ecosystems, some inorganic mercury is converted to methylmercury, the form that ultimately accumulates in fish. The rate of mercury methylation, thus the amount of methylmercury produced, varies greatly in time and space, and depends on numerous environmental factors, including temperature and the amounts of oxygen, organic matter, and sulfate that are present.Methylmercury enters aquatic food webs when it is taken up from water by algae and other microorganisms. Methylmercury concentrations increase with successively higher trophic levels in the food web—a process known as bioaccumulation. In general, fish at the top of the food web consume other fish and tend to accumulate the highest methylmercury concentrations.This report summarizes selected stream studies

  16. Rapid Determination of Mercury in Seafood in an Introductory Environmental Science Class

    ERIC Educational Resources Information Center

    Rice, Jeanette K.; Jenkins, J. David; Manley, A. Citabria; Sorel, Eric; Smith, C. Jimmy

    2005-01-01

    An experiment is described which allows easy, rapid determination of mercury levels in commercially seafood samples from a contaminated area. Students gain experience in the preparation of a calibration curve, the determination of unknown concentrations, and risk assessment based on experimentally determined data.

  17. Inorganic mercury exposure: toxicological effects, oxidative stress biomarkers and bioaccumulation in the tropical freshwater fish matrinxã, Brycon amazonicus (Spix and Agassiz, 1829).

    PubMed

    Monteiro, Diana Amaral; Rantin, Francisco Tadeu; Kalinin, Ana Lúcia

    2010-01-01

    Alterations in the antioxidant cellular system have often been proposed as biomarkers of pollutant-mediated toxicity. This study evaluated the effects of mercury on oxidative stress biomarkers and bioaccumulation in the liver, gills, white muscle and heart of the freshwater fish matrinxã, Brycon amazonicus, exposed to a nominal and sub-lethal concentration (~20% of 96 h-LC(50)) of 0.15 mg L(-1) of mercury chloride (HgCl(2)) for 96 h in a static system. Increases in superoxide dismutase, catalase, glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR) were observed in all tissues after HgCl(2) exposure, except for white muscle GR activity and hepatic GPx. In the liver and gills, the exposure to HgCl(2) also induced significant increases in reduced glutathione (GSH). Conversely, exposure to HgCl(2) caused a significant decrease in the GSH levels and an increase in the oxidized glutathione (GSSG) content in the white muscle, while both GSH and GSSG levels increased significantly in the heart muscle. Metallothionein concentrations were significantly high after HgCl(2) exposure in the liver, gills and heart, but remained at control values in the white muscle. HgCl(2) exposure induced oxidative damage, increasing the lipid peroxidation and protein carbonyl content in all tissues. Mercury accumulated significantly in all the fish tissue. The pattern of accumulation follows the order gills > liver > heart > white muscle. In conclusion, these data suggest that oxidative stress in response to inorganic mercury exposure could be the main pathway of toxicity induced by this metal in fish.

  18. Methods for measuring specific rates of mercury methylation and degradation and their use in determining factors controlling net rates of mercury methylation

    SciTech Connect

    Ramlal, P.S.; Rudd, J.W.M.; Hecky, R.E.

    1986-01-01

    A method was developed to estimate specific rates of demethylation of methyl mercury in aquatic samples by measuring the volatile /sup 14/C end products of /sup 14/CH/sub 3/HgI demethylation. This method was used in conjuction with a /sup 203/Hg/sup 2 +/ radiochemical method which determines specific rates of mercury methylation. Together, these methods enabled us to examine some factors controlling the net rate of mercury methylation. The methodologies were field tested, using lake sediment samples from a recently flooded reservoir in the Southern Indian Lake system which had developed a mercury contamination problem in fish. Ratios of the specific rates of methylation/demethylation were calculated. The highest ratios of methylation/demethylation were calculated. The highest ratios of methylation/demethylation occurred in the flooded shorelines of Southern Indian Lake. These results provide an explanation for the observed increases in the methyl mercury concentrations in fish after flooding.

  19. Determination of mercury in carbon black by cold vapor atomic absorption spectrometry.

    PubMed

    Hepp, Nancy M

    2006-01-01

    Recently, a new color additive, D&C Black No. 2, a high-purity furnace black in the general category of carbon blacks, was listed as a color subject to batch certification by the U.S. Food and Drug Administration. A simple procedure was developed to determine mercury (Hg) in D&C Black No. 2, which is limited by specification to not more than 1 ppm Hg. The method uses partial acid digestion followed by cold vapor atomic absorption and was developed by modifying a method used for other color additives. The carbon black samples are treated with a mixture of nitric and hydrochloric acids and heated by microwave in sealed Teflon vessels. The resulting solutions, which are stable to Hg loss for at least 1 week, are diluted and analyzed for Hg using cold vapor atomic absorption spectrometry. Validation was performed by spiking carbon black samples with inorganic Hg (HgNO3) at levels from 0.1 to 1.5 microg/g, and by analyzing 2 standard reference materials. At the specification level of 1 ppm Hg (1 microg Hg/g), the 95% confidence interval was +/-0.01 ppm Hg (0.01 microg Hg/g). The method developed in this study gave good results for very difficult-to-analyze materials, such as coal standard reference materials and carbon black. By eliminating volatility and adsorption factors through the formation of HgCl4(-2) complexes, one can avoid using extremely hazardous acids such as HF and HClO4.

  20. Copper-mercury film electrode for cathodic stripping voltammetric determination of Se(IV).

    PubMed

    Sladkov, Vladimir; David, François; Fourest, Blandine

    2003-01-01

    The copper-mercury film electrode has been suggested for the determination of Se(IV) in a wide range of concentration from 1x10(-9) to 1x10(-6) mol L(-1)by square-wave cathodic stripping voltammetry. Insufficient reproducibility and sensitivity of the mercury film electrode have been overcome by using copper(II) ions during the plating procedure. Copper(II) has been found to be reduced and form a reproducible copper-mercury film on a glassy carbon electrode surface. The plating potential and time, the concentration of copper(II) and the concentration of the supporting electrolyte have been optimised. Microscopy has been used for a study of the morphology of the copper-mercury film. It has been found that it is the same as for the mercury one. The preconcentration step consists in electrodeposition of copper selenide on the copper-mercury film. The relative standard deviation is 4.3% for 1x10(-6) mol L(-1) of Se(IV). The limit of detection is 8x10(-10) mol L(-1) for 5 min of accumulation.

  1. Development and characterization of an annular denuder methodology for the measurement of divalent inorganic reactive gaseous mercury in ambient air.

    PubMed

    Landis, Matthew S; Stevens, Robert K; Schaedlich, Frank; Prestbo, Eric M

    2002-07-01

    Atmospheric mercury is predominantly present in the gaseous elemental form (Hg0). However, anthropogenic emissions (e.g., incineration, fossil fuel combustion) emit and natural processes create particulate-phase mercury(Hg(p)) and divalent reactive gas-phase mercury (RGM). RGM species (e.g., HgCl2, HgBr2) are water-soluble and have much shorter residence times in the atmosphere than Hg0 due to their higher removal rates through wet and dry deposition mechanisms. Manual and automated annular denuder methodologies, to provide high-resolution (1-2 h) ambient RGM measurements, were developed and evaluated. Following collection of RGM onto KCl-coated quartz annular denuders, RGM was thermally decomposed and quantified as Hg0. Laboratory and field evaluations of the denuders found the RGM collection efficiency to be >94% and mean collocated precision to be <15%. Method detection limits for sampling durations ranging from 1 to 12 h were 6.2-0.5 pg m(-3), respectively. As part of this research, the authors observed that methods to measure Hg(p) had a significant positive artifact when RGM coexists with Hg(p). This artifact was eliminated if a KCl-coated annular denuder preceded the filter. This new atmospheric mercury speciation methodology has dramatically enhanced our ability to investigate the mechanisms of transformation and deposition of mercury in the atmosphere.

  2. [Determination of mercury in shark liver by cold atom fluorescence spectrometry after microwave dissolution].

    PubMed

    Weng, Di

    2005-12-01

    The conditions for the determination of mercury in shark liver by cold atom fluorescence spectrometry (CAFS) with microwave dissolution were studied. After being dried completely, the method employed 2 mol x L(-1) HNO3-4 mol x L(-1) HCl as an oxidant, and with catalysis by V2O5, the samples were digested in a microwave oven. The mercury in absorption solution was reduced by SnCl2, and then was determined by CAFS at wavelength of 253.7 nm. 10% SnCl2 solution was used as a reductive agent for mercury. The linear range was 0-2.0 ng x mL(-1) mercury (r = 0.999 7). The detection limit was 0.05 ng x mL(-1), the relative standard deviation was 0.86%-2.22%, and the average recovery rate was 96.0%-108.5%. The method was suitable for the determination of mercury in shark liver.

  3. An Investigation of Organic and Inorganic Mercury Exposure and Blood Pressure in a Small-Scale Gold Mining Community in Ghana

    PubMed Central

    Rajaee, Mozhgon; Sánchez, Brisa N.; Renne, Elisha P.; Basu, Niladri

    2015-01-01

    There is increasing concern about the cardiovascular effects of mercury (Hg) exposure, and that organic methylmercury and inorganic Hg2+ may affect the cardiovascular system and blood pressure differentially. In small-scale gold mining communities where inorganic, elemental Hg exposures are high, little is known about the effects of Hg on blood pressure. In 2011, we assessed the relationship between Hg exposure and blood pressure (BP) in a cross-sectional study of adults from a small-scale gold mining community, Kejetia, and subsistence farming community, Gorogo, in Ghana’s Upper East Region. Participants’ resting heart rate and BP were measured, and hair and urine samples were provided to serve as biomarkers of organic and inorganic Hg exposure, respectively. Participants included 70 miners and 26 non-miners from Kejetia and 75 non-miners from Gorogo. Total specific gravity-adjusted urinary and hair Hg was higher among Kejetia miners than Kejetia non-miners and Gorogo participants (median urinary Hg: 5.17, 1.18, and 0.154 µg/L, respectively; hair Hg: 0.945, 0.419, and 0.181 µg/g, respectively). Hypertension was prevalent in 17.7% of Kejetia and 21.3% of Gorogo participants. Urinary and hair Hg were not significantly associated with systolic or diastolic BP for Kejetia or Gorogo participants while adjusting for sex, age, and smoking status. Although our results follow trends seen in other studies, the associations were not of statistical significance. Given the unique study population and high exposures to inorganic Hg, the work contained here will help increase our understanding of the cardiovascular effects of Hg. PMID:26308023

  4. An Investigation of Organic and Inorganic Mercury Exposure and Blood Pressure in a Small-Scale Gold Mining Community in Ghana.

    PubMed

    Rajaee, Mozhgon; Sánchez, Brisa N; Renne, Elisha P; Basu, Niladri

    2015-08-21

    There is increasing concern about the cardiovascular effects of mercury (Hg) exposure, and that organic methylmercury and inorganic Hg(2+) may affect the cardiovascular system and blood pressure differentially. In small-scale gold mining communities where inorganic, elemental Hg exposures are high, little is known about the effects of Hg on blood pressure. In 2011, we assessed the relationship between Hg exposure and blood pressure (BP) in a cross-sectional study of adults from a small-scale gold mining community, Kejetia, and subsistence farming community, Gorogo, in Ghana's Upper East Region. Participants' resting heart rate and BP were measured, and hair and urine samples were provided to serve as biomarkers of organic and inorganic Hg exposure, respectively. Participants included 70 miners and 26 non-miners from Kejetia and 75 non-miners from Gorogo. Total specific gravity-adjusted urinary and hair Hg was higher among Kejetia miners than Kejetia non-miners and Gorogo participants (median urinary Hg: 5.17, 1.18, and 0.154 µg/L, respectively; hair Hg: 0.945, 0.419, and 0.181 µg/g, respectively). Hypertension was prevalent in 17.7% of Kejetia and 21.3% of Gorogo participants. Urinary and hair Hg were not significantly associated with systolic or diastolic BP for Kejetia or Gorogo participants while adjusting for sex, age, and smoking status. Although our results follow trends seen in other studies, the associations were not of statistical significance. Given the unique study population and high exposures to inorganic Hg, the work contained here will help increase our understanding of the cardiovascular effects of Hg.

  5. Stripping voltammetric determination of mercury(II) at antimony-coated carbon paste electrode.

    PubMed

    Ashrafi, Amir M; Vytřas, Karel

    2011-10-15

    A new procedure was elaborated to determine mercury(II) using an anodic stripping square-wave voltammetry at the antimony film carbon paste electrode (SbF-CPE). In highly acidic medium of 1M hydrochloric acid, voltammetric measurements can be realized in a wide potential window. Presence of cadmium(II) allows to separate peaks of Hg(II) and Sb(III) and apparently catalyses reoxidation of electrolytically accumulated mercury, thus allowing its determination at ppb levels. Calibration dependence was linear up to 100 ppb Hg with a detection limit of 1.3 ppb. Applicability of the method was tested on the real river water sample.

  6. Ionic liquid-based zinc oxide nanofluid for vortex assisted liquid liquid microextraction of inorganic mercury in environmental waters prior to cold vapor atomic fluorescence spectroscopic detection.

    PubMed

    Amde, Meseret; Liu, Jing-Fu; Tan, Zhi-Qiang; Bekana, Deribachew

    2016-01-01

    Zinc oxide nanofluid (ZnO-NF) based vortex assisted liquid liquid microextraction (ZnO-NF VA-LLME) was developed and employed in extraction of inorganic mercury (Hg(2+)) in environmental water samples, followed by cold vapor atomic fluorescence spectrometry (CV-AFS). Unlike other dispersive liquid liquid microextraction techniques, ZnO-NF VA-LLME is free of volatile organic solvents and dispersive solvent consumption. Analytical signals were obtained without back-extraction from the ZnO-NF phase prior to CV-AFS determination. Some essential parameters of the ZnO-NF VA-LLME and cold vapor generation such as composition and volume of the nanofluid, vortexing time, pH of the sample solution, amount of the chelating agent, ionic strength and matrix interferences have been studied. Under optimal conditions, efficient extraction of 1ng/mL of Hg(2+) in 10mL of sample solution was achieved using 50μL of ZnO-NF. The enrichment factor before dilution, detection limits and limits of quantification of the method were about 190, 0.019 and 0.064ng/mL, respectively. The intra and inter days relative standard deviations (n=8) were found to be 4.6% and 7.8%, respectively, at 1ng/mL spiking level. The accuracy of the current method was also evaluated by the analysis of certified reference materials, and the measured Hg(2+) concentration of GBW08603 (9.6ng/mL) and GBW(E)080392 (8.9ng/mL) agreed well with their certified value (10ng/mL). The method was applied to the analysis of Hg(2+) in effluent, influent, lake and river water samples, with recoveries in the range of 79.8-92.8% and 83.6-106.1% at 1ng/mL and 5ng/mL spiking levels, respectively. Overall, ZnO-NF VA-LLME is fast, simple, cost-effective and environmentally friendly and it can be employed for efficient enrichment of the analyte from various water samples.

  7. Determination of total mercury in fillets of sport fishes collected from Folsom Reservoir, California, 2006

    USGS Publications Warehouse

    May, Thomas W.; Brumbaugh, William G.

    2007-01-01

    This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the U.S. Bureau of Reclamation, to determine mercury concentrations in selected sport fishes from Folsom Reservoir in California. Fillets were collected from each fish sample, and after homogenization and lyophilization of fish fillets, mercury concentrations were determined with a direct mercury analyzer utilizing the process of thermal combustion-gold amalgamation atomic absorption spectroscopy. Mercury concentrations in fillets ranged from 0.031 to 0.20 micrograms per gram wet weight in rainbow trout (Oncorhynchus mykiss) samples and 0.071 to 0.16 micrograms per gram wet weight in bluegill (Lepomis macrochirus) samples. Mercury concentration was 0.98 microgram per gram wet weight in a single spotted bass (Micropterus punctulatus) sample, which was the only one in the sample set which exceeded the U.S. Environmental Protection Agency's fish consumption advisory of 0.30 microgram per gram wet weight.

  8. AQUEOUS AND VAPOR PHASE MERCURY SORPTION BY INORGANIC OXIDE MATERIALS FUNCTIONALIZED WITH THIOLS AND POLY-THIOLS

    EPA Science Inventory

    The objective of the study is the development of sorbents where the sorption sites are highly accessible for the capture of mercury from aqueous and vapor streams. Only a small fraction of the equilibrium capacity is utilized for a sorbent in applications involving short residenc...

  9. Distribution of inorganic mercury in liver and kidney of beluga and bowhead whales through autometallographic development of light microscopic tissue sections.

    PubMed

    Woshner, Victoria M; Ohara, Todd M; Eurell, Jo Ann; Wallig, Matthew A; Bratton, Gerald R; Suydam, Robert S; Beasley, Val R

    2002-01-01

    Inorganic mercury was localized through autometallography (AMG) in kidney and liver of free-ranging, subsistence-harvested beluga (Delphinapterus leucus: n = 20) and bowhead (Balaena mysticetrus: n = 5) whales. AMG granules were not evident in bowhead tissues, confirming nominal mercury (Hg) concentrations (range = 0.011 to 0.038 microg/g ww for total Hg). In belugas, total Hg ranged from 0.30 to 17.11 and from 0.33 to 82.47 microg/g ww in liver and kidney, respectively. AMG granules were restricted to cortical tubular epithelial cytoplasm in belugas with lower tissue burdens; whales with higher tissue burdens had granules throughout the uriniferous tubular epithelium. In liver, AMG granular densities differed between lobular zones, concentrating in stellate macrophages and bile cannalicular domains of hepatocytes. AMG granules aggregated in periportal regions in belugas with lower hepatic Hg concentrations, yet among whales with higher Hg, AMG granule deposition extended to pericentral and midzonal regions of liver lobules. Mean areas occupied by AMG granules correlated well with hepatic Hg concentrations and age. In beluga livers, AMG staining density was not associated with lipofuscin quantity (an index of oxidative damage). Occasionally, AMG granules and lipofuscin were colocalized, but more often were not, implying that Hg was not a prominent factor in hepatic lipofuscin deposition in belugas.

  10. Waterscape determinants of net mercury methylation in a tropical wetland.

    PubMed

    Lázaro, Wilkinson L; Díez, Sergi; da Silva, Carolina J; Ignácio, Áurea R A; Guimarães, Jean R D

    2016-10-01

    The periphyton associated with freshwater macrophyte roots is the main site of Hg methylation in different wetland environments in the world. The aim of this study was to test the use of connectivity metrics of water bodies, in the context of patches, in a tropical waterscape wetland (Guapore River, Amazonia, Brazil) as a predictor of potential net methylmercury (MeHg) production by periphyton communities. We sampled 15 lakes with different patterns of lateral connectivity with the main river channel, performing net mercury methylation potential tests in incubations with local water and Eichhornia crassipes root-periphyton samples, using (203)HgCl2 as a tracer. Physico-chemical variables, landscape data (morphological characteristics, land use, and lateral connection type of water bodies) using GIS resources and field data were analyzed with Generalized Additive Models (GAM). The net Me(203)Hg production (as % of total added (203)Hg) was expressive (6.2-25.6%) showing that periphyton is an important matrix in MeHg production. The model that best explained the variation in the net Me(203)Hg production (76%) was built by the variables: connection type, total phosphorus and dissolved organic carbon (DOC) in water (AICc=48.324, p=0.001). Connection type factor was the best factor to model fit (r(2)=0.32; p=0.008) and temporarily connected lakes had higher rates of net mercury methylation. Both DOC and total phosphorus showed positive significant covariation with the net methylation rates (r(2)=0.26; p=0.008 and r(2)=0.21; p=0.012 respectively). Our study suggests a strong relationship between rates of net MeHg production in this tropical area and the type of water body and its hydrological connectivity within the waterscape.

  11. Ultraviolet vapor generation atomic fluorescence spectrometric determination of mercury in natural water with enrichment by on-line solid phase extraction

    NASA Astrophysics Data System (ADS)

    Qin, Deyuan; Gao, Feng; Zhang, Zhaohui; Zhao, Liqian; Liu, Jixin; Ye, Jianping; Li, Junwei; Zheng, Fengxi

    2013-10-01

    A novel method, which coupled an on-line solid phase extraction (SPE) enrichment with ultraviolet vapor generation (UVG) atomic fluorescence spectrometry (AFS), was developed to improve the sensitivity of mercury determination and to remove the interference of some anion and organics to UVG of mercury. A high mercury retention efficiency and maximum exclusion of inorganic and organic matrix in water samples were achieved by using C18 SPE mini cartridge modified with sodium diethyldithiocarbamate (DDTC). Fast and efficient elution from the cartridge was found by using L-cysteine mixing solution. Furthermore, through the investigation of different UV reactor designs, the most important factor was the structure of the reactor (which corresponded roughly to the photon flux) wherein the tubing was sintered into the UV lamp to give the highest UV generation efficiency. The second factor was the materials of the tubing (which roughly corresponded to the working wavelength). Synthetic quartz, characterized by the highest transparency at 185 nm, attained the highest UVG efficiency, suggesting that the most favorable wavelength for UVG was 185 nm. Under optimum conditions, the achievable detection limit (3σ) with sample loadings of 10.0 mL was 0.03 ng L- 1 and 0.08 ng L- 1 with different manifolds, respectively. The method was successfully applied to the determination of Hg in tap water, river water and lake water samples.

  12. Mercury and mercury compounds toxicology. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    Not Available

    1994-04-01

    The bibliography contains citations concerning the toxic effects of mercury and mercury compounds on biological systems. Mercury metal, mercury vapors, organic mercury compounds, mercury halides, and other inorganic mercury compounds are discussed. Citations include acute, chronic, environmental, metabolic, and pathological effects; and clinical biochemistry of mercury exposure. Heavy metal pollution and bioaccumulation are referenced in related bibliographies. (Contains 250 citations and includes a subject term index and title list.)

  13. A flow-through fluorescent sensor to determine Fe(III) and total inorganic iron.

    PubMed

    Pulido-Tofiño, P; Moreno, J M; Pérez-Conde, M C

    2000-03-06

    A flow-through fluorescent sensor for the consecutive determination of Fe(III) and total iron is described. The reactive phase of the proposed sensor, which has a high affinity for complexed Fe(III), consists of pyoverdin immobilized on controlled pore glass (CPG) by covalent bonding. This pigment selectively reacts with Fe(III) decreasing its fluorescence emission. Total inorganic iron is determined as Fe(III) after on-line oxidation in a mini-column containing persulphate immobilized on an ion exchange resin. The developed method allows the determination of Fe(III) in the 3-200 (g l(-1) range. The relative standard deviations of 10 determinations of 60 (g l(-1) of Fe(III) and 20 (g l(-1) of Fe(III)+Fe(II) are 3 and 5%, respectively. The sensor has been satisfactorily applied to speciate iron in synthetic, tap and well waters and wines. There were no significant differences for total inorganic iron determination between this new method and the atomic absorption spectroscopy reference method at the 95% confidence level. The sensor allows the concentration of Fe(II) to be calculated as the difference between total inorganic iron and Fe(III). The lifetime of the sensor is at least 3 months in continuous use or the equivalent of 1000 determinations.

  14. Determination of mercury(II) ion by electrochemical cold vapor generation atomic absorption spectrometry.

    PubMed

    Arbab-Zavar, M Hosein; Rounaghi, G Hosein; Chamsaz, Mahmoud; Masrournia, Mahboube

    2003-05-01

    A technique for determination of mercury is described; it is based on electrolytic reduction of Hg(II) ion on a graphite cathode, the trapping of mercury vapor and its volatilization into a quartz tube aligned in the optical path of an atomic absorption spectrometer. The electrochemical cell consisted of a graphite cathode and an anode operating with constant direct current for the production of mercury atoms. A pre-activated graphite rod was used as the cathode material. The optimum conditions for electrochemical generation of mercury cold vapor (the electrolysis time and current, the flow rate, the type of electrode and electrolyte) were investigated. The characteristic electrochemical data with chemical cold vapor using NaBH4-acid were compared. The presence of cadmium(II), arsenic(III), antimony(III), selenium(IV), bismuth(III), silver(I), lead(II), lithium(I), sodium(I) and potassium(I) showed interference effects which were eliminated by suitable separation techniques. The calibration curve is linear over the range of 5-90 ng ml(-1) mercury(II). The detection limit is 2 ng ml(-1) of Hg(II) and the RSD is 2.5% (n = 10) for 40 ng ml(-1). The accuracy and recovery of the method were investigated by analyzing spiked tap water and river water.

  15. Synthesis of hydrochloric acid solution for total mercury determination in natural waters.

    PubMed

    Patel-Sorrentino, Nathalie; Benaim, Jean-Yves; Cossa, Daniel; Lucas, Yves

    2011-01-01

    Total mercury (Hg(T)) determination requires the addition of concentrated hydrochloric acid solution (≥10 mol L(-1) HCl) in relatively high amounts to preserve the samples and to prepare reagent solutions. A method for the preparation of concentrated HCl with Hg(T) concentration of lower than 5 ng L(-1) is described in this article. It is based on the well-known chemical reaction: 2 NH(4)Cl + H(2)SO(4) → (NH(4))(2)SO(4) + 2 HCl. This method is validated thanks to the US Environmental Protection Agency method 1631 and standard reference materials BCR-579 (mercury in coastal seawater).

  16. Slurry sampling in serum blood for mercury determination by CV-AFS.

    PubMed

    Aranda, Pedro R; Gil, Raúl A; Moyano, Susana; De Vito, Irma; Martinez, Luis D

    2009-01-30

    The heavy metal mercury (Hg) is a neurotoxin known to have a serious health impact even at relatively low concentrations. A slurry method was developed for the sensitive and precise determination of mercury in human serum blood samples by cold vapor generation coupled to atomic fluorescence spectrometry (CV-AFS). All variables related to the slurry formation were studied. The optimal hydrochloric concentration and tin(II) chloride concentration for CV generation were evaluated. Calibration within the range 0.1-10 microg L(-1) Hg was performed with the standard addition method, and compared with an external calibration. Additionally, the reliability of the results obtained was evaluated by analyzing mercury in the same samples, but submitted to microwave-assisted digestion method. The limit of detection was calculated as 25 ng L(-1) and the relative standard deviation was 3.9% at levels around of 0.4 microg L(-1)Hg.

  17. Determination of Mercury in Milk by Cold Vapor Atomic Fluorescence: A Green Analytical Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Armenta, Sergio; de la Guardia, Miguel

    2011-01-01

    Green analytical chemistry principles were introduced to undergraduate students in a laboratory experiment focused on determining the mercury concentration in cow and goat milk. In addition to traditional goals, such as accuracy, precision, sensitivity, and limits of detection in method selection and development, attention was paid to the…

  18. [Study on the determination of 14 inorganic elements in coffee by inductively coupled plasma mass spectrometry].

    PubMed

    Nie, Xi-Du; Fu, Liang

    2013-07-01

    Samples of coffee were digested by microwave digestion, and inorganic elements amounts of Na, Mg, P, Ca, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Mo and Pb in sample solutions were determined by inductively coupled plasma mass spectrometry (ICP-MS). HNO3 + H2O2 was used to achieve the complete decomposition of the organic matrix in a closed-vessel microwave oven. The working parameters of the instrument were optimized. The results showed that the relative standard deviation (RSD) was less than 3.84% for all the elements, and the recovery was found to be 92.00% -106.52% by adding standard recovery experiment. This method was simple, sensitive and precise and can perform simultaneous multi-elements determination of coffee, which could satisfy the sample examination request and provide scientific rationale for determining inorganic elements of coffee.

  19. Single-Walled Carbon Nanotubes (SWCNTs), as a Novel Sorbent for Determination of Mercury in Air

    PubMed Central

    Golbabaei, Farideh; Ebrahimi, Ali; Shirkhanloo, Hamid; Koohpaei, Alireza; Faghihi-Zarandi, Ali

    2016-01-01

    Background: Based on the noticeable toxicity and numerous application of mercury in industries, removal of mercury vapor through sorbent is an important environmental challenge. Purpose of the Study: Due to their highly porous and hollow structure, large specific surface area, light mass density and strong interaction, Single-Walled Carbon Nanotubes (SWCNTs) sorbent were selected for this investigation. Methods: In this study, instrumental conditions, method procedure and different effective parameters such as adsorption efficiency, desorption capacity, time, temperature and repeatability as well as retention time of adsorbed mercury were studied and optimized. Also, mercury vapor was determined by cold vapor atomic absorption spectrometry (CV-AAS). Obtained data were analyzed by Independent T- test, Multivariate linear regression and one way–ANOVA finally. Results: For 80 mg nanotubes, working range of SWCNT were achieved 0.02-0.7 μg with linear range (R2=0.994). Our data revealed that maximum absorption capacity was 0.5 μg g-1 as well as limit of detection (LOD) for studied sorbent was 0.006 μg. Also, optimum time and temperature were reported, 10 min and 250 °C respectively. Retention time of mercury on CNTs for three weeks was over 90%. Results of repeated trials indicated that the CNTs had long life, so that after 30 cycles of experiments, efficiency was determined without performance loss. Conclusion: Results showed that carbon nanotubes have high potential for efficient extraction of mercury from air and can be used for occupational and environmental purposes. The study of adsorption properties of CNTs is recommended. PMID:26925918

  20. Reproductive toxicity of inorganic mercury exposure in adult zebrafish: Histological damage, oxidative stress, and alterations of sex hormone and gene expression in the hypothalamic-pituitary-gonadal axis.

    PubMed

    Zhang, Qun-Fang; Li, Ying-Wen; Liu, Zhi-Hao; Chen, Qi-Liang

    2016-08-01

    Mercury (Hg) is a prominent environmental contaminant that causes a variety of adverse effects on aquatic organisms. However, the mechanisms underlying inorganic Hg-induced reproductive impairment in fish remains largely unknown. In this study, adult zebrafish were exposed to 0 (control), 15 and 30μg Hg/l (added as mercuric chloride, HgCl2) for 30days, and the effects on histological structure, antioxidant status and sex hormone levels in the ovary and testis, as well as the mRNA expression of genes involved in the hypothalamic-pituitary-gonadal (HPG) axis were analyzed. Exposure to Hg caused pathological lesions in zebrafish gonads, and changed the activities and mRNA levels of antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)) as well as the content of glutathione (GSH) and malondialdehyde (MDA). In females, although ovarian 17β-estradiol (E2) content remained relatively stable, significant down-regulation of lhβ, gnrh2, gnrh3, lhr and erα were observed. In males, testosterone (T) levels in the testis significantly decreased after Hg exposure, accompanied by down-regulated expression of gnrh2, gnrh3, fshβ and lhβ in the brain as well as fshr, lhr, ar, cyp17 and cyp11b in the testis. Thus, our study indicated that waterborne inorganic Hg exposure caused histological damage and oxidative stress in the gonads of zebrafish, and altered sex hormone levels by disrupting the transcription of related HPG-axis genes, which could subsequently impair the reproduction of fish. Different response of the antioxidant defense system, sex hormone and HPG-axis genes between females and males exposed to inorganic Hg indicated the gender-specific regulatory effect by Hg. To our knowledge, this is the first time to explore the effects and mechanisms of inorganic Hg exposure on reproduction at the histological, enzymatic and molecular levels, which will greatly extend our understanding on the mechanisms underlying of reproductive

  1. Determination of mercury by cold-vapor technique in several tissues of treated American red crayfish (Procambarus clarkii)

    SciTech Connect

    Del Ramo, J.; Pastor, A.; Diaz-Mayans, J.; Medina, J.; Torreblanca, A.

    1988-01-01

    Adult intermolt specimens of American red crayfish (Procambarus clarkii) collected from Lake Albufera (Valencia, Spain), were exposed to mercury during 96 h. The Hg-concentrations used were 50, 100, and 250 ..mu..g Hg/l as Cl/sub 2/Hg. The content of mercury in muscle, midgut gland, antennal glands and gills was investigated. Determinations of mercury were made by cold-vapor technique and AAS. The mercury levels in all examined tissues increased significantly with increasing Hg-concentration in the water.

  2. Mercury contamination in the Yatsushiro Sea, south-western Japan: spatial variations of mercury in sediment.

    PubMed

    Tomiyasu, T; Nagano, A; Yonehara, N; Sakamoto, H; Rifardi; Oki, K; Akagi, H

    2000-08-10

    Mercury-contaminated effluent was discharged into Minamata Bay from a chemical plant over a 20-year period until 1965 (from 1958 to 1959, effluent was discharged into Minamata River), causing Minamata disease. In an effort to characterize the extent of the contamination in the Yatsushiro Sea, the vertical and horizontal distributions of mercury in sediment were investigated. Sediment was sampled at 62 locations in the southern part of the sea from 4 to 6 March 1996. In the lower layers of the long cores of sediment, the total amount of mercury was at a relatively uniform low concentration. We interpret these low values to represent the background concentration absent of anthropogenic influence. The background value thus estimated for the Yatsushiro Sea was 0.059 +/- 0.013 mg kg(-1) (mean +/- S.D., n = 51). The highest concentration in each sample ranged from 0.086 to 3.46 mg kg(-1) (mean, 0.57 mg kg(-1)). The higher values were obtained at stations near Minamata Bay and the Minamata River (the sources of the pollution). Concentrations decreased with distance from the source. An inspection of the vertical profiles of mercury concentration in cores suggested that the deposited mercury had not been fixed in sediment but had been transported, despite 30 years having past since the last discharge of contaminated effluent. At nine stations, extractable inorganic and organic mercury concentrations were determined differentially. Inorganic mercury is the predominant species in sediment and organic mercury comprising approximately 1% of the total.

  3. Determination of total mercury in biological tissue by isotope dilution ICPMS after UV photochemical vapor generation.

    PubMed

    Liu, Rui; Xu, Mo; Shi, Zeming; Zhang, Jiayun; Gao, Ying; Yang, Lu

    2013-12-15

    A method is developed for the determination of trace mercury in biological samples using photo chemical vapor generation (PVG) and isotope dilution inductively coupled plasma mass spectrometry (ID ICPMS) detection. Biological tissues were solubilized in formic acid. Subsequently, the sample solutions were exposed to an ultraviolet (UV) source for the reduction of mercury into vapor species prior to ICPMS measurements. The formic acid served not only as a tissue solubilizer in the sample preparation procedure, but also as a photochemical reductant for mercury in the PVG process. The problem arising from the opaque formic acid digested solution was efficiently solved by using ID method. The optimum conditions for sample treatment and PVG were investigated. A limit of detection (LOD) of 0.5 pg g(-1), based on an external calibration, provided 350-fold improvement over that obtained by utilizing conventional pneumatic nebulization sample introduction. Method validation was demonstrated by the determination of total mercury in several biological tissue certified reference materials (CRMs). The results were in good agreement with the certified values.

  4. DoE optimization of a mercury isotope ratio determination method for environmental studies.

    PubMed

    Berni, Alex; Baschieri, Carlo; Covelli, Stefano; Emili, Andrea; Marchetti, Andrea; Manzini, Daniela; Berto, Daniela; Rampazzo, Federico

    2016-05-15

    By using the experimental design (DoE) technique, we optimized an analytical method for the determination of mercury isotope ratios by means of cold-vapor multicollector ICP-MS (CV-MC-ICP-MS) to provide absolute Hg isotopic ratio measurements with a suitable internal precision. By running 32 experiments, the influence of mercury and thallium internal standard concentrations, total measuring time and sample flow rate was evaluated. Method was optimized varying Hg concentration between 2 and 20 ng g(-1). The model finds out some correlations within the parameters affect the measurements precision and predicts suitable sample measurement precisions for Hg concentrations from 5 ng g(-1) Hg upwards. The method was successfully applied to samples of Manila clams (Ruditapes philippinarum) coming from the Marano and Grado lagoon (NE Italy), a coastal environment affected by long term mercury contamination mainly due to mining activity. Results show different extents of both mass dependent fractionation (MDF) and mass independent fractionation (MIF) phenomena in clams according to their size and sampling sites in the lagoon. The method is fit for determinations on real samples, allowing for the use of Hg isotopic ratios to study mercury biogeochemical cycles in complex ecosystems.

  5. Determination of trace amounts of mercury using hierarchically nanostructured europium oxide.

    PubMed

    Peng, Yanfen; Chen, Xiaojun; Gao, Zhiqiang

    2010-10-15

    This work reports a highly sensitive procedure for the determination of trace amounts of mercury, based on fluorescence quenching of thenoyltrifluoroacetone (TTA) capped hierarchically nanostructured europium oxide (cHN-Eu(2)O(3)). The HN-Eu(2)O(3) consisted of nanometer-thick Eu(2)O(3) sheets self-organized into nano- and micro-sized monoliths with a hierarchical architecture while retaining its desirable fluorescence properties. The fluorescence intensity of the cHN-Eu(2)O(3) was 1000 times higher than that of commercial Eu(2)O(3) nanoparticles (equivalent weight) when it was capped with TTA, suggesting that a synergetic effect, confining the longtime Eu(3+) excitation within the nanostructure and light-harvesting effect of the capping agent, is responsible for this fluorescence enhancement. Excellent interaction between the cHN-Eu(2)O(3) and solution species is expected owing to its large surface area, high surface-to-bulk ratio, and ultrahigh fluorescence intensity. As an example, aqueous suspensions of the cHN-Eu(2)O(3) were used as sensing agent for the determination of trace amounts of mercury. A linear relationship between the concentration of mercury and fluorescence quenching was observed from 10 ppb to 10 ppm with a correlation coefficient of 0.997 and a detection limit of 5.0 ppb. Mercury in various samples was analyzed using the cHN-Eu(2)O(3) suspension.

  6. Experimental determination of cavitation thresholds in liquid water and mercury

    SciTech Connect

    Taleyarkhan, R.P.; Gulec, K.; West, C.D.; Haines, J.

    1998-09-01

    It is well-known that fluids (like solids) will break apart or form voids when put under sufficient tension. The present study has been motivated by the need to evaluate the impact of fluid cavitation in spallation neutron source target systems, more specifically for the proposed 1-MW Spallation Neutron Source (SNS) project, which is being designed in collaboration between Oak Ridge National Laboratory (ORNL), Los Alamos National Laboratory, Lawrence Berkeley National Laboratory, Brookhaven National Laboratory, and Argonne National Laboratory. Indeed, results of SNS-specific simulations have indicated that the onset of cavitation could play a very significant role in reducing imposed stresses in structural components of the SNS. In general, the cavitation of fluids is target systems is important to consider for a variety of reasons. Its occurrence can have significant impact on heat transfer, pressure pulse generation, fluid jetting on to structures, surface erosion, stresses induced in enclosures, etc. Therefore, it is important to evaluate the threshold pressure under which the fluid in tension will undergo cavitation. Another major aspect concerns the possible onset of cavitation in an oscillating pressure field; i.e., one would need to know if fluids such as mercury and water will cavitate if the imposed tensile pressure in the fluid is of short duration. If indeed it takes sufficiently long for cavitation bubbles to nucleate, then it would be possible to disregard the complexities involved with addressing cavitation-related issues. This paper provides an overview of preliminary work done to date to derive information on cavitation onset in a relatively static and in a high-frequency environment.

  7. Measuring total mercury due to small-scale gold mining activities to determine community vulnerability in Cihonje, Central Java, Indonesia.

    PubMed

    Sari, Mega M; Inoue, Takanobu; Matsumoto, Yoshitaka; Yokota, Kuriko

    2016-01-01

    This research is comparative study of gold mining and non-gold mining areas, using four community vulnerability indicators. Vulnerability indicators are exposure degree, contamination rate, chronic, and acute toxicity. Each indicator used different samples, such as wastewater from gold mining process, river water from Tajum river, human hair samples, and health questionnaire. This research used cold vapor atomic absorption spectrometry to determine total mercury concentration. The result showed that concentration of total mercury was 2,420 times than the maximum content of mercury permitted in wastewater based on the Indonesian regulation. Moreover, the mercury concentration in river water reached 685 ng/l, exceeding the quality threshold standards of the World Health Organization (WHO). The mercury concentration in hair samples obtained from the people living in the research location was considered to identify the health quality level of the people or as a chronic toxicity indicator. The highest mercury concentration--i.e. 17 ng/mg, was found in the gold mining respondents. Therefore, based on the total mercury concentration in the four indicators, the community in the gold mining area were more vulnerable to mercury than communities in non-gold mining areas. It was concluded that the community in gold mining area was more vulnerable to mercury contamination than the community in non-gold mining area.

  8. Inorganic and organic mercury chloride toxicity to Coturnix: Sensitivity related to age and quantal assessment of physiologic responses

    USGS Publications Warehouse

    Hill, E.F.

    1982-01-01

    The toxicities of mercuric chloride (HgCl(,2)) and methylmercuric chloride (CH(,3)HgCl) were compared for coturnix (Coturnix coturnix japonica) from hatching to adulthood. Comparisons were based on: (1) Median lethal dosages (LD50) derived by administering single peroral and single intramuscular dosages of mercury, (2) median lethal concentrations (LC50) derived by feeding mercury for 5 days, (3) median toxic concentrations (TC50) derived by feeding mercury 9 weeks and measuring plasma enzyme activity, plasma electrolytes, and other blood constituents, and (4) transient changes of various blood chemistries following a single peroral dose of mercury. Acute peroral and intramuscular LD50s for HgCl(,2) and CH(,3)HgCl increased by two- to threefold for coturnix chicks from hatching to 4 weeks of age. Concomitantly, the LC50s also increased, but the important difference between test procedures was that with both single dose routes of exposure the toxicity ratios, i.e., HgCl(,2)/CH(,3)HgCl, at each age were about 2 to 2.5 compared to about 100 for the LC50s. For example, at 2 weeks of age the peroral LD50s for HgCl(,2) and CH(,3)HgCl were 42 and 18 mg/kg; the dietary LC50s were 5086 and 47 ppm for HgCl(,2) and CH(,3)HgCl. The 9 week feeding trial was not associated with gross effects from either HgCl(,2) at 0.5 to 32 ppm or CH(,3)HgCl at 0.125 to 8 ppm. However, subtle responses were detected for the plasma enzymes aspartate aminotransferase, lactate dehydrogenase, and ornithine carbamoyl transferase and could be quantified by probit analysis. This quantal procedure was based on establishment of a normal value for each enzyme and classing outliers as respondents. A 'hazard index' based on the TC50 for an enzyme divided by the LD50 or LC50 was introduced. The single oral dosages of HgCl(,2) and CH(,3)HgCl showed that ratios of alanine aminotransferase, lactate dehydrogenase, and orinthine carbamoyl transferase for the liver and kidneys of adult coturnix were opposite from

  9. Inorganic and organic mercury chloride toxicity to Coturnix: sensitivity related to age and quantal assessment of physiologic responses

    USGS Publications Warehouse

    Hill, E.F.

    1981-01-01

    The toxicities of mercuric chloride (HgCl(,2)) and methylmercuric chloride (CH(,3)HgCl) were compared for coturnix (Coturnix coturnix japonica) from hatching to adulthood. Comparisons were based on: (1) Median lethal dosages (LD50) derived by administering single peroral and single intramuscular dosages of mercury, (2) median lethal concentrations (LC50) derived by feeding mercury for 5 days, (3) median toxic concentrations (TC50) derived by feeding mercury 9 weeks and measuring plasma enzyme activity, plasma electrolytes, and other blood constituents, and (4) transient changes of various blood chemistries following a single peroral dose of mercury. Acute peroral and intramuscular LD50s for HgCl(,2) and CH(,3)HgCl increased by two- to threefold for coturnix chicks from hatching to 4 weeks of age. Concomitantly, the LC50s also increased, but the important difference between test procedures was that with both single dose routes of exposure the toxicity ratios, i.e., HgCl(,2)/CH(,3)HgCl, at each age were about 2 to 2.5 compared to about 100 for the LC50s. For example, at 2 weeks of age the peroral LD50s for HgCl(,2) and CH(,3)HgCl were 42 and 18 mg/kg; the dietary LC50s were 5086 and 47 ppm for HgCl(,2) and CH(,3)HgCl. The 9 week feeding trial was not associated with gross effects from either HgCl(,2) at 0.5 to 32 ppm or CH(,3)HgCl at 0.125 to 8 ppm. However, subtle responses were detected for the plasma enzymes aspartate aminotransferase, lactate dehydrogenase, and ornithine carbamoyl transferase and could be quantified by probit analysis. This quantal procedure was based on establishment of a normal value for each enzyme and classing outliers as respondents. A 'hazard index' based on the TC50 for an enzyme divided by the LD50 or LC50 was introduced. The single oral dosages of HgCl(,2) and CH(,3)HgCl showed that ratios of alanine aminotransferase, lactate dehydrogenase, and orinthine carbamoyl transferase for the liver and kidneys of adult coturnix were opposite from

  10. Determining mercury levels in anchovy and in individuals with different fish consumption habits, together with their neurological effects.

    PubMed

    Çamur, Derya; Güler, Çağatay; Vaizoğlu, Songül Acar; Özdilek, Betül

    2016-07-01

    An increase in enviromental pollution may lead to mercury toxicity of fish origin due to the accumulative nature of methylmercury in fish. The main sources of human exposure to organic mercury compounds are contaminated fish and other seafoods. This descriptive study was planned to determine mercury levels in anchovy and in hair samples from individuals with different fish consumption habits, and to evaluate those individuals in terms of toxic effects. For that purpose, we analyzed 100 anchovies from the Black Sea and 100 anchovies from the Sea of Marmara, and assessed 25 wholesale workers in fish markets and 25 cleaning firm employees from both Ankara and Istanbul. Mercury levels in samples were measured using a cold vapor atomic absorption spectrophotometer. Participants were examined neurologically and mini mental state examination was applied to evaluate their cognitive functions. Mercury levels in fish were found to be below the national and international permitted levels. There was no statistically significant relation between mercury levels and the sea from which fish were caught. Hair mercury levels for all participants were within permitted ranges. However, hair mercury levels in both cities increased significantly with amount and frequency of fish consumption. A significant correlation was determined at correlation analysis between levels of fish consumption and hair mercury levels in the fishmongers and in the entire group (r = 0.32, p = 0.025; r = 0.23, p = 0.023, respectively). Neurological examination results were normal, except for a decrease in deep tendon reflexes in some participants in both cities. There was no correlation between Standardized Mini Mental State Examination results and hair mercury levels. We conclude that establishing a monitoring system for mercury levels in fish and humans will be useful in terms of evaluating potential neurotoxic effects.

  11. Determination of mercury, cadmium and lead in human milk in Iran.

    PubMed

    Goudarzi, M A; Parsaei, P; Nayebpour, F; Rahimi, E

    2013-10-01

    Breast milk contains both essential and nonessential trace elements. Mercury, cadmium and lead are nonessential, potentially toxic heavy metals with hematotoxic, neurotoxic and nephrotoxic properties even at very low concentrations. The objectives of this study were to determine the concentrations of mercury, cadmium and lead in the breast milk of healthy lactating women who were living in Isfahan, Iran. Concentrations of mercury, cadmium and lead were determined by graphite furnace atomic absorption spectrometry in 37 milk samples from healthy lactating women collected on first to sixth postpartum week. Accuracy of the analysis was checked by various methods including the use of reference material. The mean ± SD of the concentrations of mercury, cadmium and lead in human milk were 0.92 ± 0.54 μg/L (range 0.0-2.07 μg/L), 1.92 ± 1.04 μg/L (range 0.45-5.87 μg/L) and 7.11 ± 3.96 μg/L (range 3.06-19.47 μg/L), respectively. The results of this study showed that the concentrations of mercury, lead and cadmium in the milk samples from lactating women in Isfahan were high, which makes a major public health hazard for the inhabitants, especially neonatal and children, of the industrial locations. The results of the present study indicate a need for establishing safe intake values of heavy metals in human milk.

  12. Applications of Organic and Inorganic Amendments Induce Changes in the Mobility of Mercury and Macro- and Micronutrients of Soils

    PubMed Central

    García-Sánchez, Mercedes; Šípková, Adéla; Száková, Jiřina; Kaplan, Lukáš; Ochecová, Pavla; Tlustoš, Pavel

    2014-01-01

    Both soil organic matter and sulfur (S) can reduce or even suppress mercury (Hg) mobility and bioavailability in soil. A batch incubation experiment was conducted with a Chernozem and a Luvisol artificially contaminated by 440 mg·kg−1 Hg showing wide differences in their physicochemical properties and available nutrients. The individual treatments were (i) digestate from the anaerobic fermentation of biowaste; (ii) fly ash from wood chip combustion; and (iii) ammonium sulfate, and every treatment was added with the same amount of S. The mobile Hg portion in Chernozem was highly reduced by adding digestate, even after 1 day of incubation, compared to control. Meanwhile, the outcome of these treatments was a decrease of mobile Hg forms as a function of incubation time whereas the contents of magnesium (Mg), potassium (K), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), and phosphorus (P) were stimulated by the addition of digestate in both soils. The available calcium (Ca) contents were not affected by the digestate addition. The experiment proved digestate application as the efficient measure for fast reduction of mobile Hg at extremely contaminated soils. Moreover, the decrease of the mobile mercury portion was followed by improvement of the nutrient status of the soils. PMID:25401138

  13. Applications of organic and inorganic amendments induce changes in the mobility of mercury and macro- and micronutrients of soils.

    PubMed

    García-Sánchez, Mercedes; Sípková, Adéla; Száková, Jiřina; Kaplan, Lukáš; Ochecová, Pavla; Tlustoš, Pavel

    2014-01-01

    Both soil organic matter and sulfur (S) can reduce or even suppress mercury (Hg) mobility and bioavailability in soil. A batch incubation experiment was conducted with a Chernozem and a Luvisol artificially contaminated by 440 mg · kg(-1) Hg showing wide differences in their physicochemical properties and available nutrients. The individual treatments were (i) digestate from the anaerobic fermentation of biowaste; (ii) fly ash from wood chip combustion; and (iii) ammonium sulfate, and every treatment was added with the same amount of S. The mobile Hg portion in Chernozem was highly reduced by adding digestate, even after 1 day of incubation, compared to control. Meanwhile, the outcome of these treatments was a decrease of mobile Hg forms as a function of incubation time whereas the contents of magnesium (Mg), potassium (K), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), and phosphorus (P) were stimulated by the addition of digestate in both soils. The available calcium (Ca) contents were not affected by the digestate addition. The experiment proved digestate application as the efficient measure for fast reduction of mobile Hg at extremely contaminated soils. Moreover, the decrease of the mobile mercury portion was followed by improvement of the nutrient status of the soils.

  14. Extraction spectrophotometric determination of mercury(II) using thiacrown ethers and Bromocresol Green.

    PubMed

    Saad, B; Sultan, S M

    1995-10-01

    A reasonably sensitive and highly selective spectrophotometric method for the determination of mercury(II) is proposed. The method is based on the extraction of the ion-associate formed by a mercury(II) thiacrown ether cationic complex with Bromocresol Green as the anionic counter-ion using chloroform as the extracting solvent. The effect of thiacrown ethers of different cavity sizes, namely 1,4,7,10,13-pentathiacyclopentadecane (PTP) and 1,4,7,10,13,16-hexathiacyclooctadecane (HTO), the thiacrown ether concentration, the extracting solvent, the bromocresol green concentration and the aqueous phase pH on the extraction were investigated. Measurement of the absorbance at the lambda(max) (420 nm) of the extracted ion-associate reveals that Beer's law is obeyed over 0.5-12.0 ppm mercury(II) for both ligands. Slight interference from copper(II) and cadmium(II) is exhibited by the PTP ligand, while HTO is negligibly affected by these metal ions. Strong interference from silver(I) is evident for both ligands while alkali, alkaline earth and other transition metals tested posed negligible interference. Analysis of mercury in synthetic complex mixtures was satisfactory.

  15. Determination of trace mercury in water based on N-octylpyridinium ionic liquids preconcentration and stripping voltammetry.

    PubMed

    Li, Zhenhan; Xia, Shanhong; Wang, Jinfen; Bian, Chao; Tong, Jianhua

    2016-01-15

    A novel method for determination of trace mercury in water is developed. The method is performed by extracting mercury firstly with ionic liquids (ILs) and then detecting the concentration of mercury in organic media with anodic stripping voltammetry. Liquid-liquid extraction of mercury(II) ions by four ionic liquids with N-octylpyridinium cations ([OPy](+)) was studied. N-octylpyridinium tetrafluoroborate and N-octylpyridinium trifluoromethylsulfonate were found to be efficient and selective extractant for mercury. Temperature controlled dispersive liquid phase microextraction (TC-DLPME) technique was utilized to improve the performance of preconcentration. After extraction, precipitated IL was diluted by acetonitrile buffer and mercury was detected by differential pulse stripping voltammetry (DPSV) with gold disc electrode. Mercury was enriched by 17 times while interfering ions were reduced by two orders of magnitude in the organic media under optimum condition. Sensitivity and selectivity for electrochemical determination of mercury were improved by using the proposed method. Tap, pond and waste water samples were analyzed with recoveries ranging from 81% to 107% and detection limit of 0.05 μg/L.

  16. Direct determination of mercury in white vinegar by matrix assisted photochemical vapor generation atomic fluorescence spectrometry detection

    NASA Astrophysics Data System (ADS)

    Liu, Qingyang

    2010-07-01

    This paper proposes the use of photochemical vapor generation with acetic acid as sample introduction for the direct determination of ultra-trace mercury in white vinegars by atomic fluorescence spectrometry. Under ultraviolet irradiation, the sample matrix (acetic acid) can reduce mercury ion to atomic mercury Hg 0, which is swept by argon gas into an atomic fluorescence spectrometer for subsequent analytical measurements. The effects of several factors such as the concentration of acetic acid, irradiation time, the flow rate of the carrier gas and matrix effects were discussed and optimized to give detection limits of 0.08 ng mL -1 for mercury. Using the experimental conditions established during the optimization (3% v/v acetic acid, 30 s irradiation time and 20 W mercury lamp), the precision levels, expressed as relative standard deviation, were 4.6% (one day) and 7.8% (inter-day) for mercury ( n = 9). Addition/recovery tests for evaluation of the accuracy were in the range of 92-98% for mercury. The method was also validated by analysis of vinegar samples without detectable amount of Hg spiked with aqueous standard reference materials (GBW(E) 080392 and GBW(E) 080393). The results were also compared with those obtained by acid digestion procedure and determination of mercury by ICP-MS. There was no significant difference between the results obtained by the two methods based on a t-test (at 95% confidence level).

  17. Mercury pollution in Malaysia.

    PubMed

    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

  18. Use of inorganic dryer-salts in the determination of organic contaminants in air

    SciTech Connect

    Simonov, V.A.

    1985-09-01

    This paper presents results of a study of the adsorptive activity of a number of inorganic salts relative to water vapor and to organic vapors in air under the dynamic conditions which are uses in the indicator tube method. Data are also given on the properties of dryer salts having a surface modified with glycerin. It is shown that lithium chloride on porcelain and potassium carbonate having a surface modified with glycerin can be used to dry air in determining contaminants of nonpolar and polar organic substances in it. Anhydrone on porcelain, calcium chloride, and potassium carbonate absorb some substances which are being determined and therefore are less suitable.

  19. Method validation for control determination of mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry.

    PubMed

    Torres, Daiane Placido; Martins-Teixeira, Maristela Braga; Cadore, Solange; Queiroz, Helena Müller

    2015-01-01

    A method for the determination of total mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry (TDA AAS) has been validated following international foodstuff protocols in order to fulfill the Brazilian National Residue Control Plan. The experimental parameters have been previously studied and optimized according to specific legislation on validation and inorganic contaminants in foodstuff. Linearity, sensitivity, specificity, detection and quantification limits, precision (repeatability and within-laboratory reproducibility), robustness as well as accuracy of the method have been evaluated. Linearity of response was satisfactory for the two range concentrations available on the TDA AAS equipment, between approximately 25.0 and 200.0 μg kg(-1) (square regression) and 250.0 and 2000.0 μg kg(-1) (linear regression) of mercury. The residues for both ranges were homoscedastic and independent, with normal distribution. Correlation coefficients obtained for these ranges were higher than 0.995. Limits of quantification (LOQ) and of detection of the method (LDM), based on signal standard deviation (SD) for a low-in-mercury sample, were 3.0 and 1.0 μg kg(-1), respectively. Repeatability of the method was better than 4%. Within-laboratory reproducibility achieved a relative SD better than 6%. Robustness of the current method was evaluated and pointed sample mass as a significant factor. Accuracy (assessed as the analyte recovery) was calculated on basis of the repeatability, and ranged from 89% to 99%. The obtained results showed the suitability of the present method for direct mercury measurement in fresh fish and shrimp samples and the importance of monitoring the analysis conditions for food control purposes. Additionally, the competence of this method was recognized by accreditation under the standard ISO/IEC 17025.

  20. Orbit determination and gravitational field accuracy for a Mercury transponder satellite

    NASA Technical Reports Server (NTRS)

    Vincent, Mark A.; Bender, Pater L.

    1990-01-01

    Covariance studies were performed to investigate the orbit determination problem for a small transponder satellite in a nearly circular polar orbit with 4-hour period around Mercury. With X band and Ka band Doppler and range measurements, the analysis indicates that the gravitational field through degree and order 10 can be solved for from as few as 40 separate 8-hour arcs of tracking data. In addition, the earth-Mercury distance can be determined during each ranging period with about 6-cm accuracy. The expected geoid accuracy is 10 cm up through degree 5, and 1 m through degree 8. The main error sources were the geocentric range measurement error, the uncertainties in higher degree gravity field terms, which were not solved for, and the solar radiation pressure uncertainty.

  1. High residue levels and the chemical form of mercury in tissues and organs of seabirds

    SciTech Connect

    Kim, E.Y.; Murakami, Toru; Saeki, Kazutoshi; Tatsukawa, Ryo

    1995-12-31

    Total and organic (methyl) mercury in liver, muscle, kidney and feather of 9 species of seabirds were analyzed to determine the levels and their distribution and to clarify the occurrences of high mercury levels and their detoxification process in seabirds. Total mercury levels in liver showed great variations in intra and interspecies, while organic mercury levels were less variable. As compared with species in relatively low mercury levels, the species which accumulated the high concentration of mercury like black-footed albatross exhibited the different distribution of mercury in the body: in total mercury burden, albatross species contained less than 10% in feather and over 50% in liver, while other species contained over 40% in feather and less than 20% in liver. The order of organic mercury concentrations in tissues were as follows: liver > kidney > muscle in seabirds examined, except oldsquaw. The mean percentage of organic mercury in total was 35%, 66%, and 36% in liver, muscle and kidney, respectively, for all the species. The significant negative correlations were found between organic mercury percentage to total mercury and total mercury concentrations in the liver and muscle of black-footed albatross and in the liver of laysan albatross. Furthermore, in liver, muscle, and kidney of all the species, the percentages of organic mercury had a negative trend with an increase of total mercury concentrations. The results suggest that albatross species may be capable for demethylating organic mercury in the tissues (mainly in liver), and for storing the mercury as immobilizable inorganic form in the liver as substitution for delivering organic mercury to other organs. It is noteworthy that the species with high degree of demethylation showed the lower mercury burdens in feather and slow moulting pattern.

  2. Direct determination and speciation of mercury compounds in environmental and biological samples by carbon bed atomic absorption spectroscopy

    SciTech Connect

    Skelly, E.M.

    1982-01-01

    A method was developed for the direct determination of mercury in water and biological samples using a unique carbon bed atomizer for atomic absorption spectroscopy. The method avoided sources of error such as loss of volatile mercury during sample digestion and contamination of samples through added reagents by eliminating sample pretreatment steps. The design of the atomizer allowed use of the 184.9 nm mercury resonance line in the vacuum ultraviolet region, which increased sensitivity over the commonly used spin-forbidden 253.7 nm line. The carbon bed atomizer method was applied to a study of mercury concentrations in water, hair, sweat, urine, blood, breath and saliva samples from a non-occupationally exposed population. Data were collected on the average concentration, the range and distribution of mercury in the samples. Data were also collected illustrating individual variations in mercury concentrations with time. Concentrations of mercury found were significantly higher than values reported in the literature for a ''normal'' population. This is attributed to the increased accuracy gained by eliminating pretreatment steps and increasing atomization efficiency. Absorption traces were obtained for various solutions of pure and complexed mercury compounds. Absorption traces of biological fluids were also obtained. Differences were observed in the absorption-temperatures traces of various compounds. The utility of this technique for studying complexation was demonstrated.

  3. Chemical speciation of heavy metals by surface-enhanced Raman scattering spectroscopy: identification and quantification of inorganic- and methyl-mercury in water.

    PubMed

    Guerrini, Luca; Rodriguez-Loureiro, Ignacio; Correa-Duarte, Miguel A; Lee, Yih Hong; Ling, Xing Yi; García de Abajo, F Javier; Alvarez-Puebla, Ramon A

    2014-07-21

    Chemical speciation of heavy metals has become extremely important in environmental and analytical research because of the strong dependence that toxicity, environmental mobility, persistence and bioavailability of these pollutants have on their specific chemical forms. Novel nano-optical-based detection strategies, capable of overcoming the intrinsic limitations of well-established analytic methods for the quantification of total metal ion content, have been reported, but the speciation of different chemical forms has not yet been achieved. Here, we report the first example of a SERS-based sensor for chemical speciation of toxic metal ions in water at trace levels. Specifically, the inorganic Hg(2+) and the more toxicologically relevant methylmercury (CH₃Hg(+)) are selected as analytical targets. The sensing platform consists of a self-assembled monolayer of 4-mercaptopyridine (MPY) on highly SERS-active and robust hybrid plasmonic materials formed by a dense layer of interacting gold nanoparticles anchored onto polystyrene microbeads. The co-ordination of Hg(2+) and CH₃Hg(+) to the nitrogen atom of the MPY ring yields characteristic changes in the vibrational SERS spectra of the organic chemoreceptor that can be qualitatively and quantitatively correlated to the presence of the two different mercury forms.

  4. Preparation of hybrid organic-inorganic mesoporous silicas applied to mercury removal from aqueous media: Influence of the synthesis route on adsorption capacity and efficiency.

    PubMed

    Pérez-Quintanilla, Damián; Sánchez, Alfredo; Sierra, Isabel

    2016-06-15

    New hybrid organic-inorganic mesoporous silicas were prepared by employing three different synthesis routes and mercury adsorption studies were done in aqueous media using the batch technique. The organic ligands employed for the functionalization were derivatives of 2-mercaptopyrimidine or 2-mercaptothiazoline, and the synthesis pathways used were post-synthesis, post-synthesis with surface ion-imprinting and co-condensation with ion-imprinting. The incorporation of functional groups and the presence of ordered mesopores in the organosilicas was confirmed by XRD, TEM and SEM, nitrogen adsorption-desorption isotherms, (13)C MAS-NMR, (29)Si MAS-NMR, elemental and thermogravimetric analysis. The highest adsorption capacity and selectivity observed was for the material functionalized with 2-mercaptothiazoline ligand by means the co-condensation with ion-imprinting route (1.03 mmol g(-1) at pH 6). The prepared material could be potential sorbent for the extraction of this heavy metal from environmental and drinking waters.

  5. Inorganic elemental determinations of marine traditional Chinese Medicine Meretricis concha from Jiaozhou Bay: The construction of inorganic elemental fingerprint based on chemometric analysis

    NASA Astrophysics Data System (ADS)

    Shao, Mingying; Li, Xuejie; Zheng, Kang; Jiang, Man; Yan, Cuiwei; Li, Yantuan

    2016-04-01

    The goal of this paper is to explore the relationship between the inorganic elemental fingerprint and the geographical origin identification of Meretricis concha, which is a commonly used marine traditional Chinese medicine (TCM) for the treatment of asthma and scald burns. For that, the inorganic elemental contents of Meretricis concha from five sampling points in Jiaozhou Bay have been determined by means of inductively coupled plasma optical emission spectrometry, and the comparative investigations based on the contents of 14 inorganic elements (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se and Zn) of the samples from Jiaozhou Bay and the previous reported Rushan Bay were performed. It has been found that the samples from the two bays are approximately classified into two kinds using hierarchical cluster analysis, and a four-factor model based on principle component analysis could explain approximately 75% of the detection data, also linear discriminant analysis can be used to develop a prediction model to distinguish the samples from Jiaozhou Bay and Rushan Bay with accuracy of about 93%. The results of the present investigation suggested that the inorganic elemental fingerprint based on the combination of the measured elemental content and chemometric analysis is a promising approach for verifying the geographical origin of Meretricis concha, and this strategy should be valuable for the authenticity discrimination of some marine TCM.

  6. A device for sampling and determination of total particulate mercury in ambient air.

    PubMed

    Lu, J Y; Schroeder, W H; Berg, T; Munthe, J; Schneeberger, D; Schaedlich, F

    1998-06-01

    A miniaturized device, which serves as both particulate trap and pyrolyzer for airborne particulate mercury species, is described. It has been used in combination with amalgamation/thermal desorption/cold vapor atomic fluorescence spectrometry detection for the determination of total particulate mercury (TPM) associated with atmospheric aerosols. A standard reference material (SRM 1633b, NIST) has been used for validating of the pyrolysis technique, and a relative error smaller than 3% has been obtained. Contrary to most methods currently employed, this new technique does not require any sample preparation (e.g., extraction/digestion), no manual sample transfer or sample handling, and no addition of chemicals or reagents. Hence the risk of contamination is low. The time for complete analysis is less than 10 min per sample. The concentrations of TPM determined in metropolitan Toronto ranged from 3 to 91 pg m(-)(3) with standard deviations of <±2 pg m(-)(3) for simultaneous sets of four samples. These atmospheric TPM concentration values fall within the range reported in the literature. Good agreement was obtained by the three methods compared in a field study at Ny-Ålesund (78°54'N, 11°53'E), Svalbard. The elevated values of TPM concentrations obtained using the method developed in this work may arise from the Arctic springtime conversion of atmospheric mercury from gas-phase to particulate-phase Hg species.

  7. Stabilizing Agents for Calibration in the Determination of Mercury Using Solid Sampling Electrothermal Atomic Absorption Spectrometry

    PubMed Central

    Zelinková, Hana; Červenka, Rostislav; Komárek, Josef

    2012-01-01

    Tetramethylene dithiocarbamate (TMDTC), diethyldithiocarbamate (DEDTC), and thiourea were investigated as stabilizing agents for calibration purposes in the determination of mercury using solid sampling electrothermal atomic absorption spectrometry (SS-ETAAS). These agents were used for complexation of mercury in calibration solutions and its thermal stabilization in a solid sampling platform. The calibration solutions had the form of methyl isobutyl ketone (MIBK) extracts or MIBK-methanol solutions with the TMDTC and DEDTC chelates and aqueous solutions with thiourea complexes. The best results were obtained for MIBK-methanol solutions in the presence of 2.5 g L−1 TMDTC. The surface of graphite platforms for solid sampling was modified with palladium or rhenium by using electrodeposition from a drop of solutions. The Re modifier is preferable due to a higher lifetime of platform coating. A new SS-ETAAS procedure using the direct sampling of solid samples into a platform with an Re modified graphite surface and the calibration against MIBK-methanol solutions in the presence of TMDTC is proposed for the determination of mercury content in solid environmental samples, such as soil and plants. PMID:22654606

  8. Validation of methodology for determination of the mercury methylation potential in sediments using radiotracers.

    PubMed

    Zizek, Suzana; Ribeiro Guevara, Sergio; Horvat, Milena

    2008-04-01

    Experiments to determine the mercury methylation potential were performed on sediments from two locations on the river Idrijca (Slovenia), differing in ambient mercury concentrations. The tracer used was the radioactive isotope (197)Hg. The benefit of using this tracer is its high specific activity, which enables spikes as low as 0.02 ng Hg(2+) g(-1) of sample to be used. It was therefore possible to compare the efficiency of the methylation potential experiments over a range of spike concentrations from picogram to microgram levels. The first part of the work aimed to validate the experimental blanks and the second part consisted of several series of incubation experiments on two different river sediments using a range of tracer additions. The results showed high variability in the obtained methylation potentials. Increasing Hg(2+) additions gave a decrease in the percentage of the tracer methylated during incubation; in absolute terms, the spikes that spanned four orders of magnitude (0.019-190 pg g(-1) of sediment slurry) resulted in MeHg formation between 0.01 and 0.1 ng MeHg g(-1) in Podroteja and Kozarska Grapa. Higher spikes resulted in slightly elevated MeHg production (up to a maximum of 0.27 ng g(-1)). The values of methylation potential were similar in both sediments. The results imply that the experimental determination of mercury methylation potential strongly depends on the experimental setup itself and the amount of tracer added to the system under study. It is therefore recommended to use different concentrations of tracer and perform the experiments in several replicates. The amount of mercury available for methylation in nature is usually very small. Therefore, adding very low amounts of tracer in the methylation potential studies probably gives results that have a higher environmental relevance. It is also suggested to express the results obtained in absolute amounts of MeHg produced and not just as the percentage of the added tracer.

  9. Evaluation of electron capture gas chromatographic method for determination of methyl mercury in freezer-case seafoods.

    PubMed

    Alvarez, G H; Hight, S C; Capar, S G

    1984-01-01

    A method was recently adopted by AOAC for determination of methyl-bound mercury in canned and fresh-frozen seafood by electron capture gas chromatography. That method was applied to the analysis of commercially prepared freezer-case seafoods. None of the commercially added ingredients produced electron capture responses that interfered in the analysis for methyl mercury. Recoveries of 95.7-114% were obtained in fortification studies of methyl mercury at 0.2 and 1.0 ppm levels. The applicability of aqueous methyl mercuric chloride solution for fortification studies was demonstrated.

  10. The determination of Mercury's gravity field and rotational state with the mission BepiColombo

    NASA Astrophysics Data System (ADS)

    Iess, L.; Asmar, S. W.; Milani, A.; Tortora, P.; Iafolla, V.

    Gravity field and rotational state provide accurate constraints to geophysical models of planetary interiors and have been therefore a major source of information on the internal structure of solar system bodies. Their determination is particularly important for Mercury, whose interior is the least known among terrestrial planets. Today, planetary gravity fields are best investigated by means of microwave Doppler tracking of orbiting spacecraft. In order to attain precise measurements the radio link (involving a carrier transmitted from ground to the spacecraft and retransmitted back to ground) must preserve the highest phase stability and coherence at each intervening stage. Electronic noise from ground and onboard instrumentation must be minimized and propagation noise (due to plasma and troposphere) must be kept to a minimum. This is especially important for phase instabilities induced by interplanetary plasma and solar corona, which have been the main limitation in past gravity experiments with planetary probes. Both forthcoming space missions to Mercury (NASA's Messenger and ESA's Bepi- Colombo) host radio science investigations devoted to geodesy and geophysics. While Messenger's experiment exploits the onboard telecommunication system, based upon a X-band radio link (7.1-8.4 GHz), the experiment MORE (Mercury Orbiter Radioscience Experiment) of BepiColombo makes use of a Ka-band radio link (32-34 GHz) enabled by dedicated onboard and ground hardware. The use of a Ka-band link in combination with the standard telecommunication system allows a complete cancellation of the plasma noise and two-way range rate measurements as accurate as 3 micron/s over time scales of 1000 s, independently of the solar elongation angle. The radio instrumentation includes also a wide-band ranging system (WBRS, using a 20 MHz tone) with a target two-way accuracy of 20 cm. The ranging system will be used to determine Mercury's orbit in the solar system, carrying out accurate tests

  11. Optimization of a GFAAS method for determination of total inorganic arsenic in drinking water.

    PubMed

    Michon, Jérôme; Deluchat, Véronique; Al Shukry, Raad; Dagot, Christophe; Bollinger, Jean-Claude

    2007-01-15

    The new 10mugl(-1) arsenic standard in drinking water has been a spur to the search for reliable routine analytical methods with a limit of detection at the mugl(-1) level. These methods also need to be easy to handle due to the routine analyses that are required in drinking water monitoring. Graphite furnace atomic absorption spectrometry (GFAAS) meets these requirements, but the limit of detection is generally too high except for methods using a pre-concentration or separation step. The use of a high-intensity boosted discharge hollow-cathode lamp decreases the baseline noise level and therefore allows a lower limit of detection. The temperature program, chemical matrix modifier and thermal stabilizer additives were optimized for total inorganic arsenic determination with GFAAS, without preliminary treatment. The optimal furnace program was validated with a proprietary software. The limit of detection was 0.26mugAsl(-1) for a sample volume of 16mul corresponding to 4.2pgAs. This attractive technique is rapid as 20 samples can be analysed per hour. This method was validated with arsenic reference solutions. Its applicability was verified with artificial and natural groundwaters. Recoveries from 91 to 105% with relative standard deviation <5% can be easily achieved. The effect of interfering anions and cations commonly found in groundwater was studied. Only phosphates and silicates (respectively at 4 and 20mgl(-1)) lead to significant interferences in the determination of total inorganic arsenic at 4mugl(-1).

  12. Methods for determination of inorganic substances in water and fluvial sediments

    USGS Publications Warehouse

    Fishman, Marvin J.; Friedman, Linda C.

    1989-01-01

    Chapter Al of the laboratory manual contains methods used by the U.S. Geological Survey to analyze samples of water, suspended sediments, and bottom material for their content of inorganic constituents. Included are methods for determining the concentration of dissolved constituents in water, the total recoverable and total of constituents in water-suspended sediment samples, and the recoverable and total concentrations of constituents in samples of bottom material. The introduction to the manual includes essential definitions and a brief discussion of the use of significant figures in calculating and reporting analytical results. Quality control in the water-analysis laboratory is discussed, including the accuracy and precision of analyses, the use of standard-reference water samples, and the operation of an effective quality-assurance program. Methods for sample preparation and pretreatment are given also. A brief discussion of the principles of the analytical techniques involved and their particular application to water and sediment analysis is presented. The analytical methods of these techniques are arranged alphabetically by constituent. For each method, the general topics covered are the application, the principle of the method, the interferences, the apparatus and reagents required, a detailed description of the analytical procedure, reporting results, units and significant figures, and analytical precision data, when available. More than 126 methods are given for the determination of 70 inorganic constituents and physical properties of water, suspended sediment, and bottom material.

  13. On the use of certified reference materials for assuring the quality of results for the determination of mercury in environmental samples.

    PubMed

    Bulska, Ewa; Krata, Agnieszka; Kałabun, Mateusz; Wojciechowski, Marcin

    2016-08-15

    This work focused on the development and validation of methodologies for the accurate determination of mercury in environmental samples and its further application for the preparation and certification of new reference materials (RMs). Two certified RMs ERM-CC580 (inorganic matrix) and ERM-CE464 (organic matrix) were used for the evaluation of digestion conditions assuring the quantitative recovery of mercury. These conditions were then used for the digestion of new candidates for the environmental RMs: bottom sediment (M_2 BotSed), herring tissue (M_3 HerTis), cormorant tissue (M_4 CormTis), and codfish muscle (M_5 CodTis). Cold vapor atomic absorption spectrometry (CV AAS) and inductively coupled plasma mass spectrometry (ICP MS) were used for the measurement of mercury concentration in all RMs. In order to validate and assure the accuracy of results, isotope dilution mass spectrometry (IDMS) was applied as a primary method of measurement, assuring the traceability of obtained values to the SI units: the mole, the kilogram, and the second. Results obtained by IDMS using n((200)Hg)/n((202)Hg) ratio, with estimated combined uncertainty, were as follows: (916 ± 41)/[4.5 %] ng g(-1) (M_2 BotSed), (236 ± 14)/[5.9 %] ng g(-1) (M_3 HerTis), (2252 ± 54)/[2.4 %] ng g(-1) (M_4 CormTis), and (303 ± 15)/[4.9 %] ng g(-1) (M_CodTis), respectively. Different types of detection techniques and quantification (external calibration, standard addition, isotope dilution) were applied in order to improve the quality of the analytical results. The good agreement (within less than 2.5 %) between obtained results and those derived from the Inter-laboratory Comparison, executed by the Institute of Nuclear Chemistry and Technology (Warsaw, Poland) on the same sample matrices, further validated the analytical procedures developed in this study, as well as the concentration of mercury in all four new RMs. Although the developed protocol enabling the metrological

  14. Determination of total mercury in fillets of sport fishes collected from Folsom and New Melones Reservoirs, California, 2004

    USGS Publications Warehouse

    May, Thomas W.; Brumbaugh, William G.

    2007-01-01

    This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the U.S. Bureau of Reclamation, to determine mercury concentrations in selected sport fishes from Folsom and New Melones Reservoirs in California. Fillets were collected from each fish sample, and after homogenization and lyophilization of fish fillets, mercury concentrations were determined with a direct mercury analyzer utilizing the process of thermal combustion-gold amalgamation atomic absorption spectroscopy. Mercury concentrations in fish fillets from Folsom Reservoir ranged from 0.09 to 1.16 micrograms per gram wet weight, and from New Melones Reservoir ranged from 0.03 to 0.94 microgram per gram wet weight. Most of the fish fillets from Folsom Reservoir (87 percent) and 27 percent of the fillets from New Melones Reservoir exceeded the U.S. Environmental Protection Agency's fish consumption advisory of 0.30 microgram per gram wet weight.

  15. Solid phase extraction and spectrophotometric determination of mercury by adsorption of its diphenylthiocarbazone complex on an alumina column.

    PubMed

    Rajesh, N; Gurulakshmanan, G

    2008-02-01

    A simple method has been developed for the preconcentration of mercury based on the adsorption of its diphenylthiocarbazone complex on a neutral alumina column. The influence of acidity, eluting agents, stability of the column, sample volume and interfering ions has been investigated in detail. The adsorbed complex could be eluted using environmentally benign polyethylene glycol (PEG 400) and the concentration of mercury was determined by visible spectrophotometry at a wavelength maximum of 520nm. A detection limit of 4microgL(-1) could be achieved and the developed procedure was successfully applied for the determination of mercury in spiked water samples and city waste incineration ash (CRM176). The preconcentration factor attainable for quantitative recovery (>95%) of mercury(II) was 100 for a 1000mL sample volume.

  16. Sensitive determination of trace mercury by UV-visible diffuse reflectance spectroscopy after complexation and membrane filtration-enrichment.

    PubMed

    Yin, Changhai; Iqbal, Jibran; Hu, Huilian; Liu, Bingxiang; Zhang, Lei; Zhu, Bilin; Du, Yiping

    2012-09-30

    A simple, sensitive and selective solid phase reflectometry method is proposed for the determination of trace mercury in aqueous samples. The complexation reagent dithizone was firstly injected into the properly buffered solution with vigorous stirring, which started a simultaneous formation of nanoparticles suspension of dithizone and its complexation reaction with the mercury(II) ions to make Hg-dithizone nanoparticles. After a definite time, the mixture was filtered with membrane, and then quantified directly on the surface of the membrane by using integrating sphere accessory of the UV-visible spectrophotometer. The quantitative analysis was carried out at a wavelength of 485 nm since it yielded the largest difference in diffuse reflectance spectra before and after reaction with mercury(II).A good linear correlation in the range of 0.2-4.0 μg/L with a squared correlation coefficient (R(2)) of 0.9944 and a detection limit of 0.12 μg/L were obtained. The accuracy of the method was evaluated by the analysis of spiked mercury(II) concentrations determined using this method along with those determined by the atomic fluorescence mercury vapourmeter and the results obtained were in good agreement. The proposed method was applied to the determination of mercury in tap water and river water samples with the recovery in an acceptable range (95.7-105.3%).

  17. Estimation of uncertainty of a reference material for proficiency testing for the determination of total mercury in fish in nature

    NASA Astrophysics Data System (ADS)

    Santana, L. V.; Sarkis, J. E. S.; Ulrich, J. C.; Hortellani, M. A.

    2015-01-01

    We provide an uncertainty estimates for homogeneity and stability studies of reference material used in proficiency test for determination of total mercury in fish fresh muscle tissue. Stability was estimated by linear regression and homogeneity by ANOVA. The results indicate that the reference material is both homogeneous and chemically stable over the short term. Total mercury concentration of the muscle tissue, with expanded uncertainty, was 0.294 ± 0.089 μg g-1.

  18. Comparison of leaching tests to determine and quantify the release of inorganic contaminants in demolition waste

    SciTech Connect

    Delay, Markus; Lager, Tanja; Schulz, Horst D.; Frimmel, Fritz H. . E-mail: fritz.frimmel@ebi-wasser.uka.de

    2007-07-01

    The changes in waste management policy caused by the massive generation of waste materials (e.g. construction and demolition waste material, municipal waste incineration products) has led to an increase in the reuse and recycling of waste materials. For environmental risk assessment, test procedures are necessary to examine waste materials before they can be reused. In this article, results of column and lysimeter leaching tests having been applied to inorganic compounds in a reference demolition waste material are presented. The results show a good agreement between the leaching behaviour determined with the lysimeter unit and the column units used in the laboratory. In view of less time and system requirements compared to lysimeter systems, laboratory column units can be considered as a practicable instrument to assess the time-dependent release of inorganic compounds under conditions similar to those encountered in a natural environment. The high concentrations of elements in the seepage water at the initial stage of elution are reflected by the laboratory column leaching tests. In particular, authorities or laboratories might benefit and have an easy-to-use, but nevertheless reliable, method to serve as a basis for decision-making.

  19. Chemical speciation of heavy metals by surface-enhanced Raman scattering spectroscopy: identification and quantification of inorganic- and methyl-mercury in water

    NASA Astrophysics Data System (ADS)

    Guerrini, Luca; Rodriguez-Loureiro, Ignacio; Correa-Duarte, Miguel A.; Lee, Yih Hong; Ling, Xing Yi; García de Abajo, F. Javier; Alvarez-Puebla, Ramon A.

    2014-06-01

    Chemical speciation of heavy metals has become extremely important in environmental and analytical research because of the strong dependence that toxicity, environmental mobility, persistence and bioavailability of these pollutants have on their specific chemical forms. Novel nano-optical-based detection strategies, capable of overcoming the intrinsic limitations of well-established analytic methods for the quantification of total metal ion content, have been reported, but the speciation of different chemical forms has not yet been achieved. Here, we report the first example of a SERS-based sensor for chemical speciation of toxic metal ions in water at trace levels. Specifically, the inorganic Hg2+ and the more toxicologically relevant methylmercury (CH3Hg+) are selected as analytical targets. The sensing platform consists of a self-assembled monolayer of 4-mercaptopyridine (MPY) on highly SERS-active and robust hybrid plasmonic materials formed by a dense layer of interacting gold nanoparticles anchored onto polystyrene microbeads. The co-ordination of Hg2+ and CH3Hg+ to the nitrogen atom of the MPY ring yields characteristic changes in the vibrational SERS spectra of the organic chemoreceptor that can be qualitatively and quantitatively correlated to the presence of the two different mercury forms.Chemical speciation of heavy metals has become extremely important in environmental and analytical research because of the strong dependence that toxicity, environmental mobility, persistence and bioavailability of these pollutants have on their specific chemical forms. Novel nano-optical-based detection strategies, capable of overcoming the intrinsic limitations of well-established analytic methods for the quantification of total metal ion content, have been reported, but the speciation of different chemical forms has not yet been achieved. Here, we report the first example of a SERS-based sensor for chemical speciation of toxic metal ions in water at trace levels

  20. Automated dispersive liquid-liquid microextraction coupled to high performance liquid chromatography - cold vapour atomic fluorescence spectroscopy for the determination of mercury species in natural water samples.

    PubMed

    Liu, Yao-Min; Zhang, Feng-Ping; Jiao, Bao-Yu; Rao, Jin-Yu; Leng, Geng

    2017-04-14

    An automated, home-constructed, and low cost dispersive liquid-liquid microextraction (DLLME) device that directly coupled to a high performance liquid chromatography (HPLC) - cold vapour atomic fluorescence spectroscopy (CVAFS) system was designed and developed for the determination of trace concentrations of methylmercury (MeHg(+)), ethylmercury (EtHg(+)) and inorganic mercury (Hg(2+)) in natural waters. With a simple, miniaturized and efficient automated DLLME system, nanogram amounts of these mercury species were extracted from natural water samples and injected into a hyphenated HPLC-CVAFS for quantification. The complete analytical procedure, including chelation, extraction, phase separation, collection and injection of the extracts, as well as HPLC-CVAFS quantification, was automated. Key parameters, such as the type and volume of the chelation, extraction and dispersive solvent, aspiration speed, sample pH, salt effect and matrix effect, were thoroughly investigated. Under the optimum conditions, linear range was 10-1200ngL(-1) for EtHg(+) and 5-450ngL(-1) for MeHg(+) and Hg(2+). Limits of detection were 3.0ngL(-1) for EtHg(+) and 1.5ngL(-1) for MeHg(+) and Hg(2+). Reproducibility and recoveries were assessed by spiking three natural water samples with different Hg concentrations, giving recoveries from 88.4-96.1%, and relative standard deviations <5.1%.

  1. Inorganic mercury accumulation in brain following waterborne exposure elicits a deficit on the number of brain cells and impairs swimming behavior in fish (white seabream-Diplodus sargus).

    PubMed

    Pereira, Patrícia; Puga, Sónia; Cardoso, Vera; Pinto-Ribeiro, Filipa; Raimundo, Joana; Barata, Marisa; Pousão-Ferreira, Pedro; Pacheco, Mário; Almeida, Armando

    2016-01-01

    The current study contributes to fill the knowledge gap on the neurotoxicity of inorganic mercury (iHg) in fish through the implementation of a combined evaluation of brain morphometric alterations (volume and total number of neurons plus glial cells in specific regions of the brain) and swimming behavior (endpoints related with the motor activity and mood/anxiety-like status). White seabream (Diplodus sargus) was exposed to realistic levels of iHg in water (2μgL(-1)) during 7 (E7) and 14 days (E14). After that, fish were allowed to recover for 28 days (PE28) in order to evaluate brain regeneration and reversibility of behavioral syndromes. A significant reduction in the number of cells in hypothalamus, optic tectum and cerebellum was found at E7, accompanied by relevant changes on swimming behavior. Moreover, the decrease in the number of neurons and glia in the molecular layer of the cerebellum was followed by a contraction of its volume. This is the first time that a deficit on the number of cells is reported in fish brain after iHg exposure. Interestingly, a recovery of hypothalamus and cerebellum occurred at E14, as evidenced by the identical number of cells found in exposed and control fish, and volume of cerebellum, which might be associated with an adaptive phenomenon. After 28 days post-exposure, the optic tectum continued to show a decrease in the number of cells, pointing out a higher vulnerability of this region. These morphometric alterations coincided with numerous changes on swimming behavior, related both with fish motor function and mood/anxiety-like status. Overall, current data pointed out the iHg potential to induce brain morphometric alterations, emphasizing a long-lasting neurobehavioral hazard.

  2. Inorganic mercury prevents the differentiation of SH-SY5Y cells: Amyloid precursor protein, microtubule associated proteins and ROS as potential targets.

    PubMed

    Chan, Miguel Chin; Bautista, Elizabeth; Alvarado-Cruz, Isabel; Quintanilla-Vega, Betzabet; Segovia, José

    2017-02-06

    Exposure to mercury (Hg) occurs through different pathways and forms including methylmecury (MeHg) from seafood and rice, ethylmercury (EtHg), and elemental Hg (Hg(0)) from dental amalgams and artisanal gold mining. Once in the brain all these forms are transformed to inorganic Hg (I-Hg), where it bioaccumulates and remains for long periods. Hg is a well-known neurotoxicant, with its most damaging effects reported during brain development, when cellular key events, such as cell differentiation take place. A considerable number of studies report an impairment of neuronal differentiation due to MeHg exposure, however the effects of I-Hg, an important form of Hg found in brain, have received less attention. In this study, we decided to examine the effects of I-Hg exposure (5, 10 and 20μM) on the differentiation of SH-SY5Y cells induced by retinoic acid (RA, 10μM). We observed extension of neuritic processes and increased expression of neuronal markers (MAP2, tubulin-βIII, and Tau) after RA stimulation, all these effects were decreased by the co-exposure to I-Hg. Interestingly, I-Hg increased the levels of reactive oxygen species (ROS) and nitric oxide (NO) accompanied with increased levels of inducible nitric oxide synthase (iNOS) and, dimethylarginine dimethylaminohydrolase 1 (DDHA1). Remarkably I-Hg decreased levels of nitric oxide synthase neuronal (nNOS). Moreover I-Hg reduced the levels of tyrosine hydroxylase (TH) and amyloid precursor protein (APP) a protein recently involved in neuronal differentiation. These data suggest that the exposure to I-Hg impairs cell differentiation, and point to new potential targets of Hg toxicity such as APP and NO signaling.

  3. Determination of Inorganic Cations and Anions in Chitooligosaccharides by Ion Chromatography with Conductivity Detection.

    PubMed

    Cao, Lidong; Li, Xiuhuan; Fan, Li; Zheng, Li; Wu, Miaomiao; Zhang, Shanxue; Huang, Qiliang

    2017-02-22

    Chitooligosaccharides (COSs) are a promising drug candidate and food ingredient because they are innately biocompatible, non-toxic, and non-allergenic to living tissues. Therefore, the impurities in COSs must be clearly elucidated and precisely determined. As for COSs, most analytical methods focus on the determination of the average degrees of polymerization (DPs) and deacetylation (DD), as well as separation and analysis of the single COSs with different DPs. However, little is known about the concentrations of inorganic cations and anions in COSs. In the present study, an efficient and sensitive ion chromatography coupled with conductivity detection (IC-CD) for the determination of inorganic cations Na⁺, NH₄⁺, K⁺, Mg(2+), Ca(2+), and chloride, acetate and lactate anions was developed. Detection limits were 0.01-0.05 μM for cations and 0.5-0.6 μM for anions. The linear range was 0.001-0.8 mM. The optimized analysis was carried out on IonPac CS12A and IonPac AS12A analytical column for cations and anions, respectively, using isocratic elution with 20 mM methanesulfonic acid and 4 mM sodium hydroxide aqueous solution as the mobile phase at a 1.0 mL/min flow rate. Quality parameters, including precision and accuracy, were fully validated and found to be satisfactory. The fully validated IC-CD method was readily applied for the quantification of various cations and anions in commercial COS technical concentrate.

  4. Determination of Inorganic Cations and Anions in Chitooligosaccharides by Ion Chromatography with Conductivity Detection

    PubMed Central

    Cao, Lidong; Li, Xiuhuan; Fan, Li; Zheng, Li; Wu, Miaomiao; Zhang, Shanxue; Huang, Qiliang

    2017-01-01

    Chitooligosaccharides (COSs) are a promising drug candidate and food ingredient because they are innately biocompatible, non-toxic, and non-allergenic to living tissues. Therefore, the impurities in COSs must be clearly elucidated and precisely determined. As for COSs, most analytical methods focus on the determination of the average degrees of polymerization (DPs) and deacetylation (DD), as well as separation and analysis of the single COSs with different DPs. However, little is known about the concentrations of inorganic cations and anions in COSs. In the present study, an efficient and sensitive ion chromatography coupled with conductivity detection (IC-CD) for the determination of inorganic cations Na+, NH4+, K+, Mg2+, Ca2+, and chloride, acetate and lactate anions was developed. Detection limits were 0.01–0.05 μM for cations and 0.5–0.6 μM for anions. The linear range was 0.001–0.8 mM. The optimized analysis was carried out on IonPac CS12A and IonPac AS12A analytical column for cations and anions, respectively, using isocratic elution with 20 mM methanesulfonic acid and 4 mM sodium hydroxide aqueous solution as the mobile phase at a 1.0 mL/min flow rate. Quality parameters, including precision and accuracy, were fully validated and found to be satisfactory. The fully validated IC-CD method was readily applied for the quantification of various cations and anions in commercial COS technical concentrate. PMID:28241416

  5. Proficiency testing pilot for determination of total mercury in fresh fish

    NASA Astrophysics Data System (ADS)

    de Santana, L. V.; Sarkis, J. E. S.; Ulrich, J. C.; Hortellani, M. A.

    2016-07-01

    A proficiency-testing scheme concerning total mercury determination in fish tissue involved 10 laboratories as participants, who used their regular in-house analytical methods, and the assigned value and the standard deviation used in proficiency testing program was derived from calibration against the certified reference values of the CRMs. The majority of participants obtained satisfactory Z-scores, and laboratories that need to revise their procedures were singled out. The objective these exercises were makes a useful contribution towards the production of proficiency test in Brazil. The uncertainty expanded calculated for the reference material was 22%.

  6. Atlantic mercury emission determined from continuous analysis of the elemental mercury sea-air concentration difference within transects between 50°N and 50°S

    NASA Astrophysics Data System (ADS)

    Kuss, J.; Zülicke, C.; Pohl, C.; Schneider, B.

    2011-09-01

    Mercury in the environment deserves serious concern because of the mobility of volatile elemental mercury (Hg0) in the atmosphere, in combination with the harmful effect of Hg compounds on human health and the ecosystem. A major source of global atmospheric mercury is presumed to be oceanic Hg0 emission. However, available Hg0 surface water data to reliably estimate the ocean's mercury emissions are sparse. In this study, high-resolution surface water and air measurements of Hg0 were carried out between Europe and South Africa in November 2008 and between South America and Europe in April-May 2009. On each cruise a strong enrichment of Hg0 in tropical surface water was determined that apparently followed the seasonal shift of the Intertropical Convergence Zone (ITCZ). A combination of a high Hg0 production rate constant and the actual low wind speeds, which prevented emission, probably caused the accumulation of Hg0 in surface waters of the ITCZ. Hg0 emissions in the tropics were significant only if wind speed variability on a monthly scale was considered, in which case the observed significant decline of total Hg in tropical surface waters during the northern winter could be explained. In the midlatitudes, increased autumn Hg0 emissions were calculated for November in the Northern Hemisphere and for May in the Southern Hemisphere; conversely, emissions were low during both the northern and the southern spring. Mercury removal from surface waters by Hg0 emission and sinking particles was comparable to its supply through wet and dry deposition.

  7. Procedure 5 - Quality Assurance Requirements For Vapor Phase Mercury Continuous Emissions Monitoring Systems And Sorbent Trap Monitoring Systems Used For Compliance Determination At Stationary Sources

    EPA Pesticide Factsheets

    Promulgated quality assurance procedure 5 Quality Assurance Requirements For Vapor Phase Mercury Continuous Emissions Monitoring Systems And Sorbent Trap Monitoring Systems Used For Compliance Determination At Stationary Sources

  8. Procedure 5 Quality Assurance Requirements For Vapor Phase Mercury Continuous Emissions Monitoring Systems And Sorbent Trap Monitoring Systems Used For Compliance Determination At Stationary Sources

    EPA Pesticide Factsheets

    Promulgated quality assurance Procedure 5 Quality Assurance Requirements For Vapor Phase Mercury Continuous Emissions Monitoring Systems And Sorbent Trap Monitoring Systems Used For Compliance Determination At Stationary Sources

  9. Migration of components from cork stoppers to food: challenges in determining inorganic elements in food simulants.

    PubMed

    Corona, T; Iglesias, M; Anticó, E

    2014-06-18

    The inorganic elements potentially migrating from cork to a food simulant [a hydroalcoholic solution containing 12 and 20% (v/v) ethanol] have been determined by means of inductively coupled plasma (ICP) with atomic emission and mass spectrometric detection. The experimental instrumental conditions were evaluated in depth, taking into account spectroscopic and nonspectroscopic interference caused by the presence of ethanol and other components in the sample. We report concentrations ranging from 4 μg kg(-1) for Cd to 28000 μg kg(-1) for Al in the food simulant (concentrations given in kilograms of cork). The values found for Ba, Mn, Fe, Cu, and Zn have been compared with the guideline values stated in EU Regulation 10/2011. In all cases, cork met the general safety criteria applicable to food contact material. Finally, we have proposed water as an alternative to the hydroalcoholic solution to simplify quantification of the tested elements using ICP techniques.

  10. [Determination of inorganic elements in different parts of Sonchus oleraceus L by flame atomic absorption spectrometry].

    PubMed

    Wang, Nai-Xing; Cui, Xue-Gui; Du, Ai-Qin; Mao, Hong-Zhi

    2007-06-01

    Flame atomic absorption spectrometry with air-acetylene flame was used for the determination of inorganic metal elements in different parts ( flower, leaf, stem and root) of Sonchus oleraceus L. The contents of Ca, Mg, K, Na, Fe, Mn, Cu, Zn, Cr, Co, Ni, Pb and Cd in the flower, leaf, stem and root of Sonchus oleraceus L were compared. The order from high to low of the additive weight (microg x g(-1)) for the 13 kinds of metal elements is as follows: leaf (77 213.72) > flower (47 927.15) > stem(42 280.99) > root (28 131.18). From the experimental results it was found that there were considerable differences in the contents of the metal elements in different parts, and there were richer contents of Fe, Zn, Mn and Cu in root and flower, which are necessary to human health, than in other parts.

  11. Microwave-enhanced cold vapor generation for speciation analysis of mercury by atomic fluorescence spectrometry.

    PubMed

    Wu, Li; Long, Zhou; Liu, Liwei; Zhou, Qin; Lee, Yong-Ill; Zheng, Chengbin

    2012-05-30

    A new and simple cold vapor generation technique utilizing microwave irradiation coupled with atomic fluorescence spectrometry is developed for the speciation analysis of mercury in biological and geological samples. In the presence of formic acid, inorganic mercury (Hg(2+)) and total mercury (both Hg(2+) and methylmercury (MeHg)) can be converted to mercury cold vapor (Hg(0)) by microwave irradiation without and with H(2)O(2), respectively. The cold vapor was subsequently released from the liquid phase and rapidly transported to an atomic fluorescence spectrometer for the mercury detection. Optimum conditions for vapor generation as well as interferences from concomitant ions were carefully investigated. The conventionally required evaporation of the remnants of acid or oxidants was avoided because no significant interferences from these substances were observed, and thus analyte loss and potential contamination were minimized. A limit of detection of 0.005 ng mL(-1) for total mercury or inorganic mercury was obtained. A precision of less than 3% (RSD) at 2 μg L(-1) of mercury species was typical. The accuracy of the method was validated by determination of mercury in geological and biological certified reference materials. The speciation analysis of Hg(2+) and MeHg was achieved by controlling the conditions of microwave-enhanced cold vapor generation and validated via determination of Certified Reference Materials DORM-2, DORM-3 and a real river water sample.

  12. Determination of mercury and vanadium concentration in Johnius belangerii (C) fish in Musa estuary in Persian Gulf.

    PubMed

    Fard, Neamat Jaafarzadeh Haghighi; Ravanbakhsh, Maryam; Ramezani, Zahra; Ahmadi, Mehdi; Angali, Kambiz Ahmadi; Javid, Ahmad Zare

    2015-08-15

    The main aim of this study was to determine the concentrations of mercury and vanadium in Johnius belangerii (C) fish in the Musa estuary. A total of 67 fishes were caught from the Musa estuary during five intervals of 15days in the summer of 2013. After biometric measurements were conducted, the concentrations of mercury and vanadium were measured in the muscle tissue of fish using a direct method analyzer (DMA) and a graphite furnace atomic absorption spectrophotometer, respectively. The mean concentration of mercury and vanadium in the muscle tissue of fish was 3.154±1.981 and 2.921±0.873mg/kg w.w, respectively. The generalized linear model (GLM) analysis showed a significantly positive relationship among mercury concentration, length, and weight (P=0.000). In addition, there was a significantly negative relationship between vanadium concentration and fish length (P=0.000). A reverse association was found between concentrations of mercury and vanadium. Mercury concentration exceeded the allowable standards of the Environmental Protection Agency (EPA), the World Health Organization (WHO), and the Food and Drug Administration (FDA) in J. belangerii (C).

  13. Elemental Mercury in Natural Waters: Occurrence and Determination of Particulate Hg(0).

    PubMed

    Wang, Yongmin; Li, Yanbin; Liu, Guangliang; Wang, Dingyong; Jiang, Guibin; Cai, Yong

    2015-08-18

    Elemental mercury, Hg(0), is ubiquitous in water and involved in key Hg biogeochemical processes. It is extensively studied as a purgeable dissolved species, termed dissolved gaseous mercury (DGM). Little information is available regarding nonpurgeable particulate Hg(0) in water, Hg(0) bound to suspended particulate matter (SPM), which is presumably present due to high affinity of Hg(0) adsorption on solids. By employing stable isotope tracer and isotope dilution (ID) techniques, we investigated the occurrence and quantification of particulate Hg(0) after Hg(0) being spiked into natural waters, aiming to provide firsthand information on particulate Hg(0) in water. A considerable fraction of (201)Hg(0) spiked in water (about 70% after 4 h equilibration) was bound to SPM and nonpurgeable, suggesting the occurrence of particulate Hg(0) in natural waters. A scheme, involving isotope dilution, purge and trap, and inductively coupled plasma mass spectrometry detection, was proposed to quantify particulate Hg(0) by the difference between DGM and total Hg(0), determined immediately and at equilibration after spiking ID Hg isotope, respectively. The application of this newly established method revealed the presence of particulate Hg(0) in Florida Everglades water, as the determined DGM levels (0.14 to 0.22 ng L(-1)) were remarkably lower than total Hg(0) (0.41 to 0.75 ng L(-1)).

  14. Analytical application of nano-sized titanium dioxide for the determination of trace inorganic antimony in natural waters.

    PubMed

    Hagarová, Ingrid; Matúš, Peter; Bujdoš, Marek; Kubová, Jana

    2012-03-01

    In this work, solid phase extraction (SPE) using nano-sized TiO2 as a solid sorbent was used for separation/preconcentration of total inorganic antimony (iSb) before its determination by electrothermal atomic absorption spectrometry (ETAAS). After adsorption of iSb onto nano-sized TiO2, direct TiO2-slurry sampling was used for sample injection into a graphite tube. The conditions for the reliable slurry sampling together with careful control of the temperature program for the slurry solutions were worked out. Extraction conditions for both inorganic antimony species (Sb(III) and Sb(V)) and interference studies of coexisting ions were studied in detail. The accuracy of the optimized method was checked by the certified reference material (CRM) for trace elements in lake water TMDA-61. Finally, the optimized method was used for the determination of trace inorganic antimony in synthetic and natural waters.

  15. Determination of inorganic pharmaceutical counterions using hydrophilic interaction chromatography coupled with a Corona CAD detector.

    PubMed

    Huang, Z; Richards, M A; Zha, Y; Francis, R; Lozano, R; Ruan, J

    2009-12-05

    A simple generic approach was investigated for the determination of inorganic pharmaceutical counterions in drug substances using conventional high performance liquid chromatographic (HPLC) instruments. An intuitive approach combined Corona charged aerosol detection (CAD) with a polymer-based zwitterionic stationary phase in the hydrophilic interaction chromatography (HILIC) mode. Two generic methods based on this HILIC/CAD technique were developed to quantitate counterions such as Cl-, Br-, SO(4)(2-), K+, Ca2+ and Mg2+ in different pharmaceutical compounds. The development and capability of this HILIC/CAD technique analysis were examined. HILIC/CAD was compared to ion chromatography (IC), the most commonly used methodology for pharmaceutical counterion analysis. HILIC/CAD was found to have significant advantages in terms of: (1) being able to quantitate both anions and cations simultaneously without a need to change column/eluent or detection mode; (2) imposing much less restriction on the allowable organic percentage of the eluents than IC, and therefore being more appropriate for analysis of counterions of poorly water-soluble drugs; (3) requiring minimal training of the operating analysts. The precision and accuracy of counterion analysis using HILIC/CAD was not compromised. A typical precision of <2.0% was observed for all tested inorganic counterions; the determinations were within 2.0% relative to the theoretical counterion amount in the drug substance. Additionally, better accuracy was shown for Cl- in several drug substances as compared to IC. The main drawback of HILIC/CAD is its unsuitability for many of the current silica-based HILIC columns, because slight dissolution of silica leads to high baseline noise in the CAD detector. As a result of the universal detection characteristics of Corona CAD and the unique separation capabilities of a zwitterionic stationary phase, an intuitive and robust HPLC method was developed for the generic determination of

  16. Development of extraction procedure for determination of mercury species using SPME-assisted dispersive derivative agent

    NASA Astrophysics Data System (ADS)

    Abdullah, Md Pauzi; Khalik, Wan Mohd Afiq Wan Mohd; Othman, Mohamed Rozali

    2016-11-01

    The extraction procedure for determination of low level mercury using solid phase microextraction was successfully carried out. Design of experimental works using factorial design and central composite design were applied to screen and predict the optimum condition for extraction step. In this study, variables namely concentration level (5 % m/v) and volume of derivatization solution (150 µL) has depicted as main effect for controlling the suitability of derivative reagent condition. Maximum of signal response (account as total peak areas for mercury species) was obtained when extraction procedure was set up at pH of water sample (5.8), extraction time (14 min), extraction temperature (43 °C) and stirring rate (450 rpm). Reducing time required to reach equilibrium is new improvement achieved in this study. Detection limit for each species (MeHg 26.17 ngL-1; EtHg 48.84 ngL-1 and IHg 14.11 ngL-1) was calculated lower than our previous work. Recovery, repeatability and reproducibility trial were recorded varied at acceptable range and relative standard deviation was calculated below than 10 %.

  17. Trace level voltammetric determination of heavy metals and total mercury in tea matrices (Camellia sinensis).

    PubMed

    Melucci, Dora; Locatelli, Marcello; Locatelli, Clinio

    2013-12-01

    An analytical procedure regarding the voltammetric determination of mercury(II), copper(II), lead(II), cadmium(II) and zinc(II) by square wave anodic stripping voltammetry (SWASV) in matrices involved in food chain is proposed. In particular, tea leaves were analyzed as real samples. The digestion of each matrix was carried out using a concentrated HCl-HNO3-H2SO4 acidic attack mixture; 0.01 mol L(-1) EDTA-Na2+ 0.15 mol L(-1) NaCl + 0.5 mol L(-1) HCl was employed as the supporting electrolyte. The voltammetric measurements were carried out using a conventional three electrode cell, employing, as working electrodes, a gold electrode (GE) and a stationary hanging mercury drop electrode (HMDE). The analytical procedure has been verified on the standard reference materials Spinach Leaves NIST-SRM 1570a, Tomato Leaves NIST-SRM 1573a and Apple Leaves NIST-SRM 1515. For all the elements, the precision as repeatability, expressed as relative standard deviation (sr) was of the order of 3-5%, while the trueness, expressed as relative error (e) was of the order of 3-7%. Once set up on the standard reference materials, the analytical procedure was applied to commercial tea leaves samples. A critical comparison with spectroscopic measurements is also discussed.

  18. TRACE LEVEL VOLTAMMETRIC DETERMINATION OF HEAVY METALS AND TOTAL MERCURY IN TEA MATRICES (Camellia sinensis).

    PubMed

    Melucci, Dora; Locatelli, Marcello; Locatelli, Clinio

    2013-10-24

    An analytical procedure regarding the voltammetric determination of mercury(II), copper(II), lead(II), cadmium(II) and zinc(II) by square wave anodic stripping voltammetry (SWASV) in matrices involved in food chain is proposed. In particular, tea leaves were analysed as real samples. The digestion of each matrix was carried out using a concentrated HCl-HNO3-H2SO4 acidic attack mixture; 0.01 mol L(-1) EDTA-Na2 + 0.15 mol L(-1) NaCl + 0.5 mol L(-1) HCl was employed as the supporting electrolyte. The voltammetric measurements were carried out using a conventional three electrode cell, employing, as working electrodes, a gold electrode (GE) and a stationary hanging mercury drop electrode (HMDE). The analytical procedure has been verified on the standard reference materials Spinach Leaves NIST-SRM 1570a, Tomato Leaves NIST-SRM 1573a and Apple Leaves NIST-SRM 1515. For all the elements, the precision as repeatability, expressed as relative standard deviation (sr) was of the order of 3-5 %, while the trueness, expressed as relative error (e) was of the order of 3-7 %. Once set up on the standard reference materials, the analytical procedure was applied to commercial tea leaves samples. A critical comparison with spectroscopic measurements is also discussed.

  19. A Highly Sensitive and Selective Catalytic Determination of Mercury in Environmental Samples.

    PubMed

    Mohamed, Ashraf A; Ahmed, Nagat A; El-Shahat, Mohamed F

    2016-08-01

    A simple, selective and highly sensitive spectrophotometric method has been developed for mercury determination utilizing its catalytic effect on the isoniazid-hexacyanoferrate (II) reaction. The paper presents for the first time (1) the catalytic effect of Hg (I) on the cited ligand substitution reactions and (2) the activating effect of thiourea on the behavior of mercury. The reaction was monitored spectrophotometrically at 423 nm using the initial rate method. The optimized reaction conditions were 5.0 mmol L(-1) hexacyanoferrate (II), 0.5 mmol L(-1) isoniazid, 150 mmol L(-1) citrate buffer (pH 3.30 ± 0.05), and 0.2 mmol L(-1) thiourea, at 50°C. Linear calibration graphs were obtained for 1-100 and 1-55 µg L(-1) with detection limits, based on the 3Sb-criterion, of 1.2 and 1.8 µg L(-1) of Hg (II) and Hg (I), respectively. The method was conveniently applied to samples of wastewaters, inactivated vaccines, and frozen Bass fish fillet, without any prior separation or preconcentration.

  20. Optimization of microwave digestion for mercury determination in marine biological samples by cold vapour atomic absorption spectrometry.

    PubMed

    Cardellicchio, Nicola; Di Leo, Antonella; Giandomenico, Santina; Santoro, Stefania

    2006-01-01

    Optimization of acid digestion method for mercury determination in marine biological samples (dolphin liver, fish and mussel tissues) using a closed vessel microwave sample preparation is presented. Five digestion procedures with different acid mixtures were investigated: the best results were obtained when the microwave-assisted digestion was based on sample dissolution with HNO3-H2SO4-K2Cr2O7 mixture. A comparison between microwave digestion and conventional reflux digestion shows there are considerable losses of mercury in the open digestion system. The microwave digestion method has been tested satisfactorily using two certified reference materials. Analytical results show a good agreement with certified values. The microwave digestion proved to be a reliable and rapid method for decomposition of biological samples in mercury determination.

  1. Cloud point extraction and spectrophotometric determination of mercury species at trace levels in environmental samples.

    PubMed

    Ulusoy, Halil İbrahim; Gürkan, Ramazan; Ulusoy, Songül

    2012-01-15

    A new micelle-mediated separation and preconcentration method was developed for ultra-trace quantities of mercury ions prior to spectrophotometric determination. The method is based on cloud point extraction (CPE) of Hg(II) ions with polyethylene glycol tert-octylphenyl ether (Triton X-114) in the presence of chelating agents such as 1-(2-pyridylazo)-2-naphthol (PAN) and 4-(2-thiazolylazo) resorcinol (TAR). Hg(II) ions react with both PAN and TAR in a surfactant solution yielding a hydrophobic complex at pH 9.0 and 8.0, respectively. The phase separation was accomplished by centrifugation for 5 min at 3500 rpm. The calibration graphs obtained from Hg(II)-PAN and Hg(II)-TAR complexes were linear in the concentration ranges of 10-1000 μg L(-1) and 50-2500 μg L(-1) with detection limits of 1.65 and 14.5 μg L(-1), respectively. The relative standard deviations (RSDs) were 1.85% and 2.35% in determinations of 25 and 250 μg L(-1) Hg(II), respectively. The interference effect of several ions were studied and seen commonly present ions in water samples had no significantly effect on determination of Hg(II). The developed methods were successfully applied to determine mercury concentrations in environmental water samples. The accuracy and validity of the proposed methods were tested by means of five replicate analyses of the certified standard materials such as QC Metal LL3 (VWR, drinking water) and IAEA W-4 (NIST, simulated fresh water).

  2. Simultaneous determination of mercury and organic carbon in sediment and soils using a direct mercury analyzer based on thermal decomposition-atomic absorption spectrophotometry.

    PubMed

    Chen, Jingjing; Chakravarty, Pragya; Davidson, Gregg R; Wren, Daniel G; Locke, Martin A; Zhou, Ying; Brown, Garry; Cizdziel, James V

    2015-04-29

    The purpose of this work was to study the feasibility of using a direct mercury analyzer (DMA) to simultaneously determine mercury (Hg) and organic matter content in sediment and soils. Organic carbon was estimated by re-weighing the sample boats post analysis to obtain loss-on-ignition (LOI) data. The DMA-LOI results were statistically similar (p<0.05) to the conventional muffle furnace approach. A regression equation was developed to convert DMA-LOI data to total organic carbon (TOC), which varied between 0.2% and 13.0%. Thus, mercury analyzers based on combustion can provide accurate estimates of organic carbon content in non-calcareous sediment and soils; however, weight gain from moisture (post-analysis), measurement uncertainty, and sample representativeness should all be taken into account. Sediment cores from seasonal wetland and open water areas from six oxbow lakes in the Mississippi River alluvial flood plain were analyzed. Wetland sediments generally had higher levels of Hg than open water areas owing to a greater fraction of fine particles and higher levels of organic matter. Annual loading of Hg in open water areas was estimated at 4.3, 13.4, 19.2, 20.7, 129, and 135 ng cm(-2) yr(-1) for Beasley, Roundaway, Hampton, Washington, Wolf and Sky Lakes, respectively. Generally, the interval with the highest Hg flux was dated to the 1960s and 1970s.

  3. The effect of the presence of volatile organoselenium compounds on the determination of inorganic selenium by hydride generation.

    PubMed

    Moreno, M Eva; Pérez-Conde, Concepción; Cámara, Carmen

    2003-03-01

    As a result of microbiological activity it is possible to find dimethylselenium (DMSe) and dimethyldiselenium (DMDSe) in a wide type of environmental samples, such as soils, sediments, sewage sludges and plants where methylation can take place. Selenium determination by hydride-generation (HG) techniques requires its presence as Se(IV). Consequently, inorganic speciation by hydride generation techniques is done by first determining Se(IV) and then, after reduction of Se (VI) to Se(IV), the total selenium. Therefore, the concentration of Se (VI) is evaluated as the difference between total inorganic selenium and Se(IV). In the present work it could be demonstrated that DMSe and DMDSe are forming other volatile species by reaction with sodium borohydride, applying the same reduction condition as for inorganic selenium. These species are subsequently detected by several atomic techniques (atomic absorption AAS, atomic fluorescence AFS and inductively coupled plasma-mass spectrometry ICP-MS). The error that their presence can cause in determination of inorganic selenium has been evaluated. The magnitude of this error depends on the specific analytical detector used.The coupling of pervaporation-atomic fluorescence is proposed for the identification of these species and pervaporation-gas chromatography-atomic fluorescence for their individual quantification.

  4. Gene regulation of plasmid- and chromosome-determined inorganic ion transport in bacteria.

    PubMed Central

    Silver, S; Walderhaug, M

    1992-01-01

    Regulation of chromosomally determined nutrient cation and anion uptake systems shows important similarities to regulation of plasmid-determined toxic ion resistance systems that mediate the outward transport of deleterious ions. Chromosomally determined transport systems result in accumulation of K+, Mg2+, Fe3+, Mn2+, PO4(3-), SO4(2-), and additional trace nutrients, while bacterial plasmids harbor highly specific resistance systems for AsO2-, AsO4(3-), CrO4(2-), Cd2+, Co2+, Cu2+, Hg2+, Ni2+, SbO2-, TeO3(2-), Zn2+, and other toxic ions. To study the regulation of these systems, we need to define both the trans-acting regulatory proteins and the cis-acting target operator DNA regions for the proteins. The regulation of gene expression for K+ and PO4(3-) transport systems involves two-component sensor-effector pairs of proteins. The first protein responds to an extracellular ionic (or related) signal and then transmits the signal to an intracellular DNA-binding protein. Regulation of Fe3+ transport utilizes the single iron-binding and DNA-binding protein Fur. The MerR regulatory protein for mercury resistance both represses and activates transcription. The ArsR regulatory protein functions as a repressor for the arsenic and antimony(III) efflux system. Although the predicted cadR regulatory gene has not been identified, cadmium, lead, bismuth, zinc, and cobalt induce this system in a carefully regulated manner from a single mRNA start site. The cadA Cd2+ resistance determinant encodes an E1(1)-1E2-class efflux ATPase (consisting of two polypeptides, rather than the one earlier identified). Cadmium resistance is also conferred by the czc system (which confers resistances to zinc and cobalt in Alcaligenes species) via a complex efflux pump consisting of four polypeptides. These two cadmium efflux systems are not otherwise related. For chromate resistance, reduced cellular accumulation is again the resistance mechanism, but the regulatory components are not identified

  5. Application of inorganic oxidants to the spectrophotometric determination of ribavirin in bulk and capsules.

    PubMed

    Darwish, Ibrahim A; Khedr, Alaa S; Askal, Hassan F; Mohamed, Ramadan M

    2006-01-01

    Eight spectrophotometric methods for determination of ribavirin have been developed and validated. These methods were based on the oxidation of the drug by different inorganic oxidants: ceric ammonium sulfate, potassium permanganate, ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate. The oxidation reactions were performed in perchloric acid medium for ceric ammonium sulfate and in sulfuric acid medium for the other reagents. With ceric ammonium sulfate and potassium permanganate, the concentration of ribavirin in its samples was determined by measuring the decrease in the absorption intensity of the colored reagents at 315 and 525 nm, respectively. With the other reagents, the concentration of ribavirin was determined by measuring the intensity of the developed colored reaction products at the wavelengths of maximum absorbance: 675, 780, 595, 595, 475, and 475 nm for reactions with ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate, respectively. Different variables affecting the reaction conditions were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9984-0.9998) were found between the absorbance readings and the concentrations of ribavirin in the range of 4-1400 microg/mL. The molar absorptivities were correlated with the oxidation potential of the oxidants used. The precision of the methods were satisfactory; the values of relative standard deviation did not exceed 1.64%. The proposed methods were successfully applied to the analysis of ribavirin in pure drug material and capsules with good accuracy and precision; the recovery values were 99.2-101.2 +/- 0.48-1.30%. The results obtained using the proposed spectrophotometric methods were comparable with those obtained with the official method stated in the United States Pharmacopeia.

  6. Determination of methyl mercury by aqueous phase Eehylation, followed by gas chromatographic separation with cold vapor atomic fluorescence detection

    USGS Publications Warehouse

    De Wild, John F.; Olsen, Mark L.; Olund, Shane D.

    2002-01-01

    A recent national sampling of streams in the United States revealed low methyl mercury concentrations in surface waters. The resulting median and mean concentrations, calculated from 104 samples, were 0.06 nanograms per liter (ng/L) and 0.15 ng/L, respectively. This level of methyl mercury in surface water in the United States has created a need for analytical techniques capable of detecting sub-nanogram per liter concentrations. In an attempt to create a U.S. Geological Survey approved method, the Wisconsin District Mercury Laboratory has adapted a distillation/ethylation/ gas-phase separation method with cold vapor atomic fluorescence spectroscopy detection for the determination of methyl mercury in filtered and unfiltered waters. This method is described in this report. Based on multiple analyses of surface water and ground-water samples, a method detection limit of 0.04 ng/L was established. Precision and accuracy were evaluated for the method using both spiked and unspiked ground-water and surface-water samples. The percent relative standard deviations ranged from 10.2 to 15.6 for all analyses at all concentrations. Average recoveries obtained for the spiked matrices ranged from 88.8 to 117 percent. The precision and accuracy ranges are within the acceptable method-performance limits. Considering the demonstrated detection limit, precision, and accuracy, the method is an effective means to quantify methyl mercury in waters at or below environmentally relevant concentrations

  7. Determination of mercury in an assortment of dietary supplements using an inexpensive combustion atomic absorption spectrometry technique.

    PubMed

    Levine, Keith E; Levine, Michael A; Weber, Frank X; Hu, Ye; Perlmutter, Jason; Grohse, Peter M

    2005-01-01

    The concentrations of mercury in forty, commercially available dietary supplements, were determined using a new, inexpensive analysis technique. The method involves thermal decomposition, amalgamation, and detection of mercury by atomic absorption spectrometry with an analysis time of approximately six minutes per sample. The primary cost savings from this approach is that labor-intensive sample digestion is not required prior to analysis, further automating the analytical procedure. As a result, manufacturers and regulatory agencies concerned with monitoring lot-to-lot product quality may find this approach an attractive alternative to the more classical acid-decomposition, cold vapor atomic absorption methodology. Dietary supplement samples analyzed included astragalus, calcium, chromium picolinate, echinacea, ephedra, fish oil, ginger, ginkgo biloba, ginseng, goldenseal, guggul, senna, St John's wort, and yohimbe products. Quality control samples analyzed with the dietary supplements indicated a high level of method accuracy and precision. Ten replicate preparations of a standard reference material (NIST 1573a, tomato leaves) were analyzed, and the average mercury recovery was 109% (2.0% RSD). The method quantitation limit was 0.3 ng, which corresponded to 1.5 ng/g sample. The highest found mercury concentration (123 ng/g) was measured in a concentrated salmon oil sample. When taken as directed by an adult, this product would result in an approximate mercury ingestion of 7 mug per week.

  8. Determination of Mercury in an Assortment of Dietary Supplements Using an Inexpensive Combustion Atomic Absorption Spectrometry Technique

    PubMed Central

    Levine, Michael A.; Weber, Frank X.; Hu, Ye; Perlmutter, Jason; Grohse, Peter M.

    2005-01-01

    The concentrations of mercury in forty, commercially available dietary supplements, were determined using a new, inexpensive analysis technique. The method involves thermal decomposition, amalgamation, and detection of mercury by atomic absorption spectrometry with an analysis time of approximately six minutes per sample. The primary cost savings from this approach is that labor-intensive sample digestion is not required prior to analysis, further automating the analytical procedure. As a result, manufacturers and regulatory agencies concerned with monitoring lot-to-lot product quality may find this approach an attractive alternative to the more classical acid-decomposition, cold vapor atomic absorption methodology. Dietary supplement samples analyzed included astragalus, calcium, chromium picolinate, echinacea, ephedra, fish oil, ginger, ginkgo biloba, ginseng, goldenseal, guggul, senna, St John's wort, and yohimbe products. Quality control samples analyzed with the dietary supplements indicated a high level of method accuracy and precision. Ten replicate preparations of a standard reference material (NIST 1573a, tomato leaves) were analyzed, and the average mercury recovery was 109% (2.0% RSD). The method quantitation limit was 0.3 ng, which corresponded to 1.5 ng/g sample. The highest found mercury concentration (123 ng/g) was measured in a concentrated salmon oil sample. When taken as directed by an adult, this product would result in an approximate mercury ingestion of 7 μg per week. PMID:18924735

  9. Determination of the δ13C of dissolved inorganic carbon in water; RSIL lab code 1710

    USGS Publications Warehouse

    Singleton, Glenda L.; Revesz, Kinga; Coplen, Tyler B.

    2012-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 1710 is to present a method to determine the δ13C of dissolved inorganic carbon (DIC) of water. The DIC of water is precipitated using ammoniacal strontium chloride (SrCl2) solution to form strontium carbonate (SrCO3). The δ13C is analyzed by reacting SrCO3 with 100-percent phosphoric acid (H3PO4) to liberate carbon quantitatively as carbon dioxide (CO2), which is collected, purified by vacuum sublimation, and analyzed by dual inlet isotope-ratio mass spectrometry (DI-IRMS). The DI-IRMS is a DuPont double-focusing mass spectrometer. One ion beam passes through a slit in a forward collector and is collected in the rear collector. The other measurable ion beams are collected in the front collector. By changing the ion-accelerating voltage under computer control, the instrument is capable of measuring mass/charge (m/z) 45 or 46 in the rear collector and m/z 44 and 46 or 44 and 45, respectively, in the front collector. The ion beams from these m/z values are as follows: m/z 44 = CO2 = 12C16O16O, m/z 45 = CO2 = 13C16O16O primarily, and m/z 46 = CO2 = 12C16O18O primarily. The data acquisition and control software calculates δ13C values.

  10. Mercury Underpotential Deposition to Determine Iridium and Iridium Oxide Electrochemical Surface Areas

    SciTech Connect

    Alia, Shaun M.; Hurst, Katherine E.; Kocha, Shyam S.; Pivovar, Bryan S.

    2016-06-02

    Determining the surface areas of electrocatalysts is critical for separating the key properties of area-specific activity and electrochemical surface area from mass activity. Hydrogen underpotential deposition and carbon monoxide oxidation are typically used to evaluate iridium (Ir) surface areas, but are ineffective on oxides and can be sensitive to surface oxides formed on Ir metals. Mercury underpotential deposition is presented in this study as an alternative, able to produce reasonable surface areas on Ir and Ir oxide nanoparticles, and able to produce similar surface areas prior to and following characterization in oxygen evolution. Reliable electrochemical surface areas allow for comparative studies of different catalyst types and the characterization of advanced oxygen evolution catalysts. Lastly, they also enable the study of catalyst degradation in durability testing, both areas of increasing importance within electrolysis and electrocatalysis.

  11. Mercury Underpotential Deposition to Determine Iridium and Iridium Oxide Electrochemical Surface Areas

    DOE PAGES

    Alia, Shaun M.; Hurst, Katherine E.; Kocha, Shyam S.; ...

    2016-06-02

    Determining the surface areas of electrocatalysts is critical for separating the key properties of area-specific activity and electrochemical surface area from mass activity. Hydrogen underpotential deposition and carbon monoxide oxidation are typically used to evaluate iridium (Ir) surface areas, but are ineffective on oxides and can be sensitive to surface oxides formed on Ir metals. Mercury underpotential deposition is presented in this study as an alternative, able to produce reasonable surface areas on Ir and Ir oxide nanoparticles, and able to produce similar surface areas prior to and following characterization in oxygen evolution. Reliable electrochemical surface areas allow for comparativemore » studies of different catalyst types and the characterization of advanced oxygen evolution catalysts. Lastly, they also enable the study of catalyst degradation in durability testing, both areas of increasing importance within electrolysis and electrocatalysis.« less

  12. Tracing mercury pathways in Augusta Bay (southern Italy) by total concentration and isotope determination.

    PubMed

    Bonsignore, M; Tamburrino, S; Oliveri, E; Marchetti, A; Durante, C; Berni, A; Quinci, E; Sprovieri, M

    2015-10-01

    The mercury (Hg) pollution of sediments is the main carrier of Hg for the biota and, subsequently, for the local fish consumers in Augusta Bay area (SE Sicily, Italy), a coastal marine system affected by relevant sewage from an important chlor-alkali factory. This relationship was revealed by the determination of Mass Dependent (MDF) and Mass Independent Fractionation (MIF) of Hg isotopes in sediment, fish and human hair samples. Sediments showed MDF but no MIF, while fish showed MIF, possibly due to photochemical reduction in the water column and depending on the feeding habitat of the species. Benthic and demersal fish exhibited MDF similar to that of sediments in which anthropogenic Hg was deposited, while pelagic organisms evidenced higher MDF and MIF due to photoreduction. Human hair showed high values of δ(202)Hg (offset of +2.2‰ with respect to the consumed fish) and Δ(199)Hg, both associated to fish consumption.

  13. An evaluation of a reagentless method for the determination of total mercury in aquatic life

    USGS Publications Warehouse

    Haynes, Sekeenia; Gragg, Richard D.; Johnson, Elijah; Robinson, Larry; Orazio, Carl E.

    2006-01-01

    Multiple treatment (i.e., drying, chemical digestion, and oxidation) steps are often required during preparation of biological matrices for quantitative analysis of mercury; these multiple steps could potentially lead to systematic errors and poor recovery of the analyte. In this study, the Direct Mercury Analyzer (Milestone Inc., Monroe, CT) was utilized to measure total mercury in fish tissue by integrating steps of drying, sample combustion and gold sequestration with successive identification using atomic absorption spectrometry. We also evaluated the differences between the mercury concentrations found in samples that were homogenized and samples with no preparation. These results were confirmed with cold vapor atomic absorbance and fluorescence spectrometric methods of analysis. Finally, total mercury in wild captured largemouth bass (n = 20) were assessed using the Direct Mercury Analyzer to examine internal variability between mercury concentrations in muscle, liver and brain organs. Direct analysis of total mercury measured in muscle tissue was strongly correlated with muscle tissue that was homogenized before analysis (r = 0.81, p < 0.0001). Additionally, results using this integrated method compared favorably (p < 0.05) with conventional cold vapor spectrometry with atomic absorbance and fluorescence detection methods. Mercury concentrations in brain were significantly lower than concentrations in muscle (p < 0.001) and liver (p < 0.05) tissues. This integrated method can measure a wide range of mercury concentrations (0-500 ??g) using small sample sizes. Total mercury measurements in this study are comparative to the methods (cold vapor) commonly used for total mercury analysis and are devoid of laborious sample preparation and expensive hazardous waste. ?? Springer 2006.

  14. Mercury study report to Congress. Volume 4. Health effects of mercury and mercury compounds. Sab review draft

    SciTech Connect

    Schoeny, R.

    1996-06-01

    This volume of the draft Mercury Study Report to Congress summarizes the available information on human health effects and animal data for hazard identification and dose-response assessment for three forms of mercury: elemental mercury, mercury chloride (inorganic mercury), and methylmercury (organic mercury). Effects are summarized by endpoint. The risk assessment evaluates carcinogenicity, mutagenicity, developmental toxicity and general systemic toxicity of these chemical species of mercury. Toxicokinetics (absorption, distribution, metabolism and excretion) are described for each of the three mercury species. PBPK models are described, but not applied in risk assessment. Reference doses are calculated for inorganic and methylmercury; a reference concentration for inhaled elemental mercury is provided. A quantitiative analysis of factors contributing to variability and uncertainty in the methylmercury RfD is provided in an appendix. Interations and sensitive populations are described.

  15. Estimate of the uncertainty in measurement for the determination of mercury in seafood by TDA AAS.

    PubMed

    Torres, Daiane Placido; Olivares, Igor R B; Queiroz, Helena Müller

    2015-01-01

    An approach for the estimate of the uncertainty in measurement considering the individual sources related to the different steps of the method under evaluation as well as the uncertainties estimated from the validation data for the determination of mercury in seafood by using thermal decomposition/amalgamation atomic absorption spectrometry (TDA AAS) is proposed. The considered method has been fully optimized and validated in an official laboratory of the Ministry of Agriculture, Livestock and Food Supply of Brazil, in order to comply with national and international food regulations and quality assurance. The referred method has been accredited under the ISO/IEC 17025 norm since 2010. The approach of the present work in order to reach the aim of estimating of the uncertainty in measurement was based on six sources of uncertainty for mercury determination in seafood by TDA AAS, following the validation process, which were: Linear least square regression, Repeatability, Intermediate precision, Correction factor of the analytical curve, Sample mass, and Standard reference solution. Those that most influenced the uncertainty in measurement were sample weight, repeatability, intermediate precision and calibration curve. The obtained result for the estimate of uncertainty in measurement in the present work reached a value of 13.39%, which complies with the European Regulation EC 836/2011. This figure represents a very realistic estimate of the routine conditions, since it fairly encompasses the dispersion obtained from the value attributed to the sample and the value measured by the laboratory analysts. From this outcome, it is possible to infer that the validation data (based on calibration curve, recovery and precision), together with the variation on sample mass, can offer a proper estimate of uncertainty in measurement.

  16. Determination of mercury in blood, urine and saliva for the biological monitoring of an exposure from amalgam fillings in a group with self-reported adverse health effects.

    PubMed

    Zimmer, Holger; Ludwig, Heidi; Bader, Michael; Bailer, Josef; Eickholz, Peter; Staehle, Hans Jörg; Triebig, Gerhard

    2002-04-01

    It has been argued that the release of mercury from amalgam fillings is of toxicological relevance. The aim of the study was to determine the internal mercury exposure of two groups differing in their attitude towards possible health hazards by mercury from amalgam fillings. It was to be examined if the two groups differ with regard to the mercury concentration in different biological matrices and to compare the results with current reference values. Blood, urine and saliva samples were analyzed from 40 female subjects who claimed to suffer from serious health damage due to amalgam fillings ("amalgam sensitive subjects"). 43 female control subjects did not claim any association ("amalgam non-sensitive controls"). Mercury was determined by means of cold vapour atomic absorption spectrometry. Number and surfaces of amalgam fillings were determined by dentists for each subject. Median (range) mercury levels in blood were 2.35 (0.25-13.40) micrograms/l for "amalgam sensitive subjects" and 2.40 (0.25-10.50) micrograms/l for "amalgam non-sensitive controls". In urine, the median mercury concentrations were 1.55 (0.06-14.70) micrograms/l and 1.88 (0.20-8.43) micrograms/g creatinine respectively. No significant differences could be found between the two groups. Mercury levels in blood and urine of the examined subjects were within the range of background levels in the general population including persons with amalgam fillings. Stimulated saliva contained 76.4 (6.7-406.0) micrograms mercury/l in "amalgam sensitive subjects" and 57.0 (2.8-559.0) micrograms mercury/l in controls (not significant). Mercury levels in saliva did not correlate with the concentrations in blood and urine, but merely with the number of amalgam fillings or of the filling surfaces. Mercury in saliva is therefore not recommended for a biological monitoring.

  17. Field studies using the oyster Crassostrea virginica to determine mercury accumulation and depuration rates

    SciTech Connect

    Palmer, S.J.; Presley, B.J.; Powell, E.N. ); Taylor, R.J. )

    1993-09-01

    Mercury as an environmental hazard, especially with regard to human health, has been of concern since the Minamata disaster. From 1966 to 1970 a chlor-alkali plant in Point Comfort, Texas released mercury-enriched wastewater (up to 29.9 kgHg/day) into Lavaca Bay (TWQB 1977). Since 1970 the Texas Department of Health (TDH) has periodically closed and then re-opened portions of Lavaca Bay to the harvesting of crabs and finfish based on their levels (<>0.5 ppm Hg wet weight) of mercury. A 1988 closure remains in effect as of this writing. Mercury contamination in Lavaca Bay organisms thus continues to be a problem 22 years after the chlor-alkali plant ceased releasing mercury into the bay. The goal of the following research was to better understand the behavior of mercury in Lavaca Bay. Oysters have been widely used as indicator species in metal pollution studies. Most such programs have focused on the concentrations of metals in oysters from different geographic areas. This study, however, investigated the rate and amount of mercury a [open quotes]clean[close quotes] oyster would accumulate when transplanted to a contaminated estuary and the rate of mercury depuration by contaminated oysters placed in a clean environment. The oysters were additionally analyzed for Ba, Cu, Fe, P, and Zn to test for the possible involvement of these metals in mercury accumulation and depuration. 17 refs., 3 figs., 2 tabs.

  18. Mercury fluxes out of glacial and non-glacial streams, as determined by continuous measurements of turbidity and CDOM

    NASA Astrophysics Data System (ADS)

    Vermilyea, A.; Nagorski, S. A.; Lamborg, C. H.; Scott, D.; Hood, E. W.

    2011-12-01

    was associated with particles. TSS in Lemon Creek was consistently greater (4-41 fold) than in Peterson Creek. This study lays the groundwork for accurately determining mercury fluxes out of watersheds that are being impacted by glacial recession. While streams in wetland/temperate forest landscapes may have higher FMHg concentrations, glacial watersheds export a greater mass of total mercury per watershed area, a dynamic that will continue to shift as our climate warms. The mercury exported from these glacial streams is of concern because it has the potential to be incorporated into marine ecosystems through methylation in estuaries.

  19. Sample weight and digestion temperature as critical factors in mercury determination in fish

    SciTech Connect

    Sadiq, M.; Zaidi, T.H.; Al-Mohana, H. )

    1991-09-01

    The concern about mercury (Hg) pollution of the marine environment started with the well publicized case of Minimata (Japan) where in the 1950s several persons died or became seriously ill after consuming fish or shellfish containing high levels of methylmercury. It is now accepted that Hg contaminated seafoods constitute a hazard to human health. To safeguard humans, accurate determination of Hg in marine biota is, therefore, very important. Two steps are involved in the determination of total Hg in biological materials: (a) decomposition of organic matrix (sample preparation), and (b) determination of Hg in aliquot samples. Although the procedures for determining Hg using the cold vapor technique are well established, sample preparation procedures have not been standardized. In general, samples of marine biota have been prepared by digesting different weights at different temperatures, by using mixtures of different chemicals and of varying quantities, and by digesting for variable durations. The objectives of the present paper were to evaluate the effects of sample weights and digestion temperatures on Hg determination in fish.

  20. Simultaneous neutron-activation determination of selenium and mercury in biological samples by volatilization.

    PubMed

    Byrne, A R; Kosta, L

    1974-10-01

    A method is described for the determination of selenium together with mercury in biological samples by neutron-activation analysis based on quantitative volatilization of both elements. The technique originally developed for mercury, based on pyrolysis with filtration of undesirable impurities and selective trapping from the gas phase, is now extended to selenium. The radionuclides (197)Hg and (75)Se, from one sample, are trapped separately and counted in a well-type NaI(Tl) detector and gamma-spectrometer for maximum sensitivity. The method has been tested by comparative analyses and analyses of standard biological materials, and gives good results. It is simple and is especially effective in studies of the interaction of mercury and selenium in biological systems; a positive correlation for these elements was found for human tissues. On décrit une méthode pour le dosage du sélénium conjointement au mercure dans les échantillons biologiques par analyse par activation de neutrons basée sur la volatilisation quantitative des deux éléments. La techniqu initialement développée pour le mercure, basée sur la pyrolyse avec filtration des impuretés indésirables et captage sélectif de la phase gazeuse, est maintenant étendue au sélénium. Les radionuclides (197)Hg et (75)Se, d'un échantillon, sont captés séparément dans un détecteur NaI(Tl) du type puits et un spectromètre gamma pour la sensibilité maximale. La méthode a été essayée par des analyses comparatives et des analyses de produits biologiques étalons, et donne de bons résultats. Elle est simple et particulièrement efficace dans les études de l'interaction du mercure et du sélénium dans des systèmes biologiques; on a trouvé une corrélation positive pour ces éléments pour des tissus humains.

  1. PATHOLOIGCAL EFFECTS OF DIETARY METHYL MERCURY IN AMERICAN KESTRELS ( FALCO SPARVERIUS)

    EPA Science Inventory

    Methyl mercury in aquatic food webs poses significant health risks to both wildlife and humans. One primary source of mercury contamination for both aquatic and terrestrial systems is atmospheric deposition of inorganic mercury from industrial emissions. Once in the environment, ...

  2. Determination of dry carbon-based sorbent injection for mercury control in utility ESP and baghouses

    SciTech Connect

    Broderick, T.; Haythornthwaite, S.; Bell, W.; Selegue, T.; Perry, M.

    1998-12-31

    Domestic coal-fired power plants emit approximately 40 to 80 metric tons of mercury to the atmosphere annually. The mercury concentration in utility flue gas is in the dilute range of 0.1 to 1 parts per billion. The EPA is assessing whether such low concentrations of mercury emissions from coal-fired utilities pose any significant health risk and whether mercury regulations would be necessary or appropriate. In anticipation of possible mercury control regulations, ADA Technologies (ADA) and TDA Research, Inc (TDA) were funded by the Department of Energy (DOE) to evaluate carbon-based sorbents for mercury control at utility coal-fired power plants. Past investigations of the use of dry carbon-based sorbent injection for mercury control on pilot-scale utility flue gas applications have shown that these sorbents are capable of removing gas-phase mercury. ADA Technologies field-tested the mercury removal capability of several carbon-based sorbents manufactured by TDA. The test facility was a DOE-owned test facility built and operated by ADA at the Public Service Company of Colorado`s Comanche Station in Pueblo, Colorado. The pilot-scale test fixture is a 600-acfm particulate control module that can be configured as an electrostatic precipitator, a pulse-jet baghouse, or a reverse-gas baghouse. It extracts a slipstream of flue gas from a coal-fired utility boiler. Sorbent is injected into the flue gas slipstream upstream of the particulate control module and is removed by the module. ADA evaluated the mercury capture efficiency of the sorbents over a range of flue gas temperatures and injection rates. In addition, the effect of flyash on mercury capture was also investigated. The test facility is configured to take flue gas from either upstream or downstream of Comanche Station`s full-scale reverse-gas baghouse, allowing tests to be conducted with normal-ash or low-ash flue gas.

  3. Determination and assessment of total mercury levels in local, frozen and canned fish in Lebanon.

    PubMed

    Obeid, Pierre J; El-Khoury, Bilal; Burger, Joanne; Aouad, Samer; Younis, Mira; Aoun, Amal; El-Nakat, John Hanna

    2011-01-01

    Fish is an important constituent of the Lebanese diet. However, very little attention in our area is given to bring awareness regarding the effect of the toxicity of mercury (Hg) mainly through fish consumption. This study aimed to report analytical data on total mercury levels in several fish species for the first time in thirty years and to also made individuals aware of the presence and danger from exposure to mercury through fish consumption. Fish samples were selected from local Lebanese markets and fisheries and included 94 samples of which were fresh, frozen, processed, and canned fish. All values were reported as microgram of mercury per gram of fish based on wet weight. The level of mercury ranged from 0.0190 to 0.5700 microg/g in fresh samples, 0.0059 to 0.0665 microg/g in frozen samples, and 0.0305 to 0.1190 microg/g in canned samples. The data clearly showed that higher levels of mercury were detected in local fresh fish as opposed to other types thus placing consumers at higher risk from mercury exposure. Moreover, the data revealed that Mallifa (yellowstripe barracuda/Sphyraena chrysotaenia), Sargous (white seabream/Diplodus sargus), Ghobbos (bogue/Boops boops), and shrimp (Penaeus sp.) were among the types containing the highest amounts of mercury. On the other hand, processed fish such as fish fillet, fish burger, small shrimp and crab are found to contain lower levels of mercury and are associated with lower exposure risks to mercury. Lebanese population should therefore, be aware to consume limited amounts of fresh local fish to minimize exposure to mercury.

  4. Methodological considerations regarding the use of inorganic 197Hg(II) radiotracer to assess mercury methylation potential rates in lake sediment

    USGS Publications Warehouse

    Perez, Catan S.; Guevara, S.R.; Marvin-DiPasquale, M.; Magnavacca, C.; Cohen, I.M.; Arribere, M.

    2007-01-01

    Methodological considerations on the determination of benthic methyl-mercury (CH3Hg) production potentials were investigated on lake sediment, using 197Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and ??-irradiation. Flash freezing showed similar CH3Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with ??-ray irradiation. No additional radiolabel was recovered in kill-control samples after an additional 24 or 65 h of incubation, suggesting that all treatments were effective at arresting Hg(II)-methylating bacterial activity, and that the initial recoveries are likely due to non-methylated 197Hg(II) carry-over in the organic extraction and/or [197Hg]CH3Hg produced via abiotic reactions. Two CH3Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO4 and HCl and (b) the same extraction with an additional back-extraction step to thiosulphate. Similar information was obtained with both methods, but the low efficiency observed and the extra work associated with the back-extraction procedure represent significant disadvantages, even tough the direct extraction involves higher Hg(II) carry over. ?? 2007 Elsevier Ltd. All rights reserved.

  5. Analysis for the presence of determinants involved in the transport of mercury across bacterial membrane from polluted water bodies of India

    PubMed Central

    Jan, Arif Tasleem; Azam, Mudsser; Choi, Inho; Ali, Arif; Haq, Qazi Mohd. Rizwanul

    2016-01-01

    Mercury, which is ubiquitous and recalcitrant to biodegradation processes, threatens human health by escaping to the environment via various natural and anthropogenic activities. Non-biodegradability of mercury pollutants has necessitated the development and implementation of economic alternatives with promising potential to remove metals from the environment. Enhancement of microbial based remediation strategies through genetic engineering approaches provides one such alternative with a promising future. In this study, bacterial isolates inhabiting polluted sites were screened for tolerance to varying concentrations of mercuric chloride. Following identification, several Pseudomonas and Klebsiella species were found to exhibit the highest tolerance to both organic and inorganic mercury. Screened bacterial isolates were examined for their genetic make-up in terms of the presence of genes (merP and merT) involved in the transport of mercury across the membrane either alone or in combination to deal with the toxic mercury. Gene sequence analysis revealed that the merP gene showed 86–99% homology, while the merT gene showed >98% homology with previously reported sequences. By exploring the genes involved in imparting metal resistance to bacteria, this study will serve to highlight the credentials that are particularly advantageous for their practical application to remediation of mercury from the environment. PMID:26887227

  6. Analysis for the presence of determinants involved in the transport of mercury across bacterial membrane from polluted water bodies of India.

    PubMed

    Jan, Arif Tasleem; Azam, Mudsser; Choi, Inho; Ali, Arif; Haq, Qazi Mohd Rizwanul

    2016-01-01

    Mercury, which is ubiquitous and recalcitrant to biodegradation processes, threatens human health by escaping to the environment via various natural and anthropogenic activities. Non-biodegradability of mercury pollutants has necessitated the development and implementation of economic alternatives with promising potential to remove metals from the environment. Enhancement of microbial based remediation strategies through genetic engineering approaches provides one such alternative with a promising future. In this study, bacterial isolates inhabiting polluted sites were screened for tolerance to varying concentrations of mercuric chloride. Following identification, several Pseudomonas and Klebsiella species were found to exhibit the highest tolerance to both organic and inorganic mercury. Screened bacterial isolates were examined for their genetic make-up in terms of the presence of genes (merP and merT) involved in the transport of mercury across the membrane either alone or in combination to deal with the toxic mercury. Gene sequence analysis revealed that the merP gene showed 86-99% homology, while the merT gene showed >98% homology with previously reported sequences. By exploring the genes involved in imparting metal resistance to bacteria, this study will serve to highlight the credentials that are particularly advantageous for their practical application to remediation of mercury from the environment.

  7. Remote Monitoring, Inorganic Monitoring

    EPA Science Inventory

    This chapter provides an overview of applicability, amenability, and operating parameter ranges for various inorganic parameters:this chapter will also provide a compilation of existing and new online technologies for determining inorganic compounds in water samples. A wide vari...

  8. Recent progress and applications of ion-exclusion/ion-exchange chromatography for simultaneous determination of inorganic anions and cations.

    PubMed

    Nakatani, Nobutake; Kozaki, Daisuke; Mori, Masanobu; Tanaka, Kazuhiko

    2012-01-01

    One of the ultimate goals of ion chromatography is to determine both anions and cations found in samples with a single chromatographic run. In the present article, recent progress in ion-exclusion/ion-exchange chromatography for the simultaneous determinations of inorganic anions and cations are reviewed. Firstly, the principle and the control for the simultaneous separation and detection of analyte ions using ion-exclusion/cation-exchange chromatography with a weakly acidic cation-exchange column are outlined. Then, advanced chromatographic techniques in terms of analytical time, selectively and sensitivity are summarized. As a related method, ion-exclusion/anion-exchange chromatography with an anion-exchange column could be used for the simultaneous determination of inorganic nitrogen species, such as ammonium, nitrite and nitrate ions. Their usefulness and applications to water-quality monitoring and related techniques are also described.

  9. An analytical protocol for the determination of total mercury concentrations in solid peat samples.

    PubMed

    Roos-Barraclough, F; Givelet, N; Martinez-Cortizas, A; Goodsite, M E; Biester, H; Shotyk, W

    2002-06-20

    Traditional peat sample preparation methods such as drying at high temperatures and milling may be unsuitable for Hg concentration determination in peats due to the possible presence of volatile Hg species, which could be lost during drying. Here, the effects of sample preparation and natural variation on measured Hg concentrations are investigated. Slight increases in mercury concentrations were observed in samples dried at room temperature and at 30 degrees C (6.7 and 2.48 ng kg(-1) h(-1), respectively), and slight decreases were observed in samples dried at 60, 90 and 105 degrees C (2.36, 3.12 and 8.52 ng kg(-1) h(-1), respectively). Fertilising the peat slightly increased Hg loss (3.08 ng kg(-1) h(-1) in NPK-fertilised peat compared to 0.28 ng kg(-1) h(-1) in unfertilised peat, when averaged over all temperatures used). Homogenising samples by grinding in a machine also caused a loss of Hg. A comparison of two Hg profiles from an Arctic peat core, measured in frozen samples and in air-dried samples, revealed that no Hg losses occurred upon air-drying. A comparison of Hg concentrations in several plant species that make up peat, showed that some species (Pinus mugo, Sphagnum recurvum and Pseudevernia furfuracea) are particularly efficient Hg retainers. The disproportionally high Hg concentrations in these species can cause considerable variation in Hg concentrations within a peat slice. The variation of water content (1.6% throughout 17-cm core, 0.97% in a 10 x 10 cm slice), bulk density (40% throughout 17-cm core, 15.6% in a 10 x 10 cm slice) and Hg concentration (20% in a 10 x 10 cm slice) in ombrotrophic peat were quantified in order to determine their relative importance as sources of analytical error. Experiments were carried out to determine a suitable peat analysis program using the Leco AMA 254, capable of determining mercury concentrations in solid samples. Finally, an analytical protocol for the determination of Hg concentrations in solid peat samples

  10. Development and Evaluation of an Analytical Method for the Determination of Total Atmospheric Mercury. Final Report.

    ERIC Educational Resources Information Center

    Chase, D. L.; And Others

    Total mercury in ambient air can be collected in iodine monochloride, but the subsequent analysis is relatively complex and tedious, and contamination from reagents and containers is a problem. A sliver wool collector, preceded by a catalytic pyrolysis furnace, gives good recovery of mercury and simplifies the analytical step. An instrumental…

  11. Determination of total arsenic, inorganic and organic arsenic species in wine.

    PubMed

    Herce-Pagliai, C; Moreno, I; González, G; Repetto, M; Cameán, A M

    2002-06-01

    Forty-five wine samples from the south of Spain of different alcoholic strength were analysed for total arsenic and its inorganic [As(III), As(V)] and organic (monomethylarsonic acid [MMAA], dimethylarsinic acid [DMAA]) species. The As levels of the wine samples ranged from 2.1 to 14.6 microg l(-1). The possible effect of the alcoholic fermentation process on the levels of the total arsenic and arsenical species was studied. The average total arsenic levels for the different samples were very similar, without significant differences between all types of wines. In table wines and sherry, the percentages of total inorganic arsenic were 18.6 and 15.6%, with DMAA or MMAA being the predominant species, respectively. In most samples, DMAA was the most abundant species, but the total inorganic aresenic fraction was considerable, representing 25.4% of the total concentration of the element. The estimated daily intakes of total arsenic and total inorganic arsenic for average Spanish consumers were 0.78 and 0.15 microg/person day(-1), respectively. The results suggest that the consumption of these types of wines makes no significant contribution to the total and inorganic arsenic intake for normal drinkers. However, wine consumption contributes a higher arsenic intake than through consumption of beers and sherry brandies.

  12. Indirect Determination of Mercury Ion by Inhibition of a Glucose Biosensor Based on ZnO Nanorods

    PubMed Central

    Chey, Chan Oeurn; Ibupoto, Zafar Hussain; Khun, Kimleang; Nur, Omer; Willander, Magnus

    2012-01-01

    A potentiometric glucose biosensor based on immobilization of glucose oxidase (GOD) on ZnO nanorods (ZnO-NRs) has been developed for the indirect determination of environmental mercury ions. The ZnO-NRs were grown on a gold coated glass substrate by using the low temperature aqueous chemical growth (ACG) approach. Glucose oxidase in conjunction with a chitosan membrane and a glutaraldehyde (GA) were immobilized on the surface of the ZnO-NRs using a simple physical adsorption method and then used as a potentiometric working electrode. The potential response of the biosensor between the working electrode and an Ag/AgCl reference electrode was measured in a 1mM phosphate buffer solution (PBS). The detection limit of the mercury ion sensor was found to be 0.5 nM. The experimental results provide two linear ranges of the inhibition from 0.5 × 10−6 mM to 0.5 × 10−4 mM, and from 0.5 × 10−4 mM to 20 mM of mercury ion for fixed 1 mM of glucose concentration in the solution. The linear range of the inhibition from 10−3 mM to 6 mM of mercury ion was also acquired for a fixed 10 mM of glucose concentration. The working electrode can be reactivated by more than 70% after inhibition by simply dipping the used electrode in a 10 mM PBS solution for 7 min. The electrodes retained their original enzyme activity by about 90% for more than three weeks. The response to mercury ions was highly sensitive, selective, stable, reproducible, and interference resistant, and exhibits a fast response time. The developed glucose biosensor has a great potential for detection of mercury with several advantages such as being inexpensive, requiring minimum hardware and being suitable for unskilled users. PMID:23202200

  13. Mercury poisoning: an unusual cause of polyarthritis.

    PubMed

    Karataş, G K; Tosun, A K; Karacehennem, E; Sepici, V

    2002-02-01

    Mercury is a toxic metal that is widely used in everyday life. It has organic and inorganic forms that are both toxic. As acute mercury poisoning is uncommon, diagnosis is difficult if the exposure is not manifest. It has usually a slow onset and non-specific symptoms. In this paper we report a patient who developed polyarthritis after mercury exposure.

  14. Resonant Rayleigh scattering for the determination of trace amounts of mercury (II) with thiocyanate and basic triphenylmethane dyes

    SciTech Connect

    Liu, S.; Liu, Z.; Zhou, G.

    1998-05-01

    Intense resonance Rayleigh scattering (RRS) appears when mercury (II) reacts with thiocyanate and a basic triphenylmethane dye (BTPMD), such as crystal violet (CV), ethyl violet (EV), brilliant green (BG), malachite green (MG) or indine green (IG), to form an ion-association complex of the type (BTPMD){sub 2}[Hg(SCN){sub 4}]. The characteristics of RRS spectra of the ion-association complexes and suitable conditions for the reactions were investigated. The intensity of RRS is directly proportional to the concentration of mercury (II) in the range of 0--2.0 {micro}g/25 ml. The RRS methods have very high sensitivities for determination of mercury (II); their detection limits are between 1.68 ng/ml and 6.00 ng/ml on different dye systems. The effects of foreign ions and ways to improve the selectivity were studied. The new highly sensitive methods for the determination of trace amounts of mercury based on the RRS of the ion-association complexes have been developed.

  15. Determination of inorganic anions in water by ion chromatography: a collaborative study.

    PubMed

    Edgell, K W; Longbottom, J E; Pfaff, J D

    1994-01-01

    The U.S. Environmental Protection Agency (U.S. EPA) and the American Society for Testing and Materials (ASTM) conducted a joint collaborative study validating an ion chromatographic method for determination fo inorganic anions (U.S. EPA method 300.0A and the equivalent proposed revision to ASTM method D4327). This study was conducted to determine the mean recovery and precision of analyses for bromide, chloride, fluoride, nitrate, nitrite, orthophosphate, and sulfate in reagent water, drinking water, and wastewater. The study design was based on Youden's nonreplicate plan for collaborative tests of analytical methods. The test waters were spiked with the anions at 6 concentration levels, prepared as 3 Youden pairs. The 22 volunteer laboratories were instructed to dilute 10 mL sample concentrate to 100 mL test water. A measured volume of sample (20-200 microL) was injected into an ion chromatograph equipped with a guard column, anion exchange column, and a chemical micromembrane suppression device. The anions were then separated using 1.7 mM sodium bicarbonate and 1.8 mM sodium carbonate, and measured by a conductivity detector. Submitted data were evaluated using U.S. EPA's IMVS computer program, which follows ASTM D2777-86 statistical guidance. U.S. EPA method 300.0A and ASTM method D4327 were judged acceptable for measurement of the above anions (except sulfate) at concentrations ranging from 0.3 to 25 mg/L and sulfate concentrations from 2.9 to 95 mg/L. Mean recoveries for the 7 anions from all matrixes, as estimated from the linear regression equations, ranged from 95 to 104%. At concentrations above 2-6 mg/L for bromide, fluoride, nitrate, nitrite, and orthophosphate, and above 24 mg/L for sulfate, the overall and single-analyst relative standard deviations were less than 10 and 6%, respectively. As concentrations decreased, precision became more variable. The relative standard deviations of results for chloride were slightly higher than the other anions

  16. Determination of pre-cecal phosphorus digestibility of inorganic phosphates and bone meal products in broilers.

    PubMed

    van Harn, J; Spek, J W; van Vuure, C A; van Krimpen, M M

    2017-02-22

    A broiler study was performed to determine the pre-cecal phosphorus (P) digestibility of 5 P sources, 3 from animal (Delfos, Calfos, and porcine bone meal) and 2 of inorganic (monocalcium phosphate [MCP] and dicalcium phosphate [DCP]) origin. Delfos is processed from bones resulting in a dicalcium phosphate product, and Calfos is processed from bones in which part of the gelatin is removed but in which the hydroxy-apatite matrix is preserved. During the first 14 d, birds were housed in floor pens bedded with wood shavings and received a commercial starter diet. At d 14, broilers were randomly assigned to pens (0.9 m2, 10 birds/pen) with a slatted floor. From d 14 onwards, one of the 6 experimental diets (a basal diet, and 5 diets containing the P sources) was provided. Test diets were replicated 6 times, and the basal diet 8 times. Electron microscopy images of test products were made in order to verify whether the spatial structure of the test products could be related to the pre-cecal P digestibility of the same products. Diets met or exceeded CVB (2011) requirements for all nutrients except for P and were formulated to contain a calcium to total P ratio of between 1.4 and 1.6 and a minimal amount of phytate P. Diets contained 5 g/kg titanium oxide as a marker to determine digestibility of P. At d 24 all birds were euthanized, after which the content of the terminal part of the ileum was sampled. The P digestibility was calculated by linear regression according to World's Poultry Science Association (WPSA) protocol for determination of pre-cecal P digestibility. Pre-cecal P digestibility of MCP, DCP, Delfos, Calfos, and porcine bone meal was 88.5, 82.4, 94.5, 86.9, and 78.2%, respectively. Based on visual inspection of electron microscopy images of test products, the spatial structure of the test products might be related to P digestibility. It is concluded that processing of bone meal increases the pre-cecal P digestibility in broilers.

  17. Methods for the determination and speciation of mercury in natural waters--a review.

    PubMed

    Leopold, Kerstin; Foulkes, Michael; Worsfold, Paul

    2010-03-24

    This review summarises current knowledge on Hg species and their distribution in the hydrosphere and gives typical concentration ranges in open ocean, coastal and estuarine waters, as well as in rivers, lakes, rain and ground waters. The importance of reliable methods for the determination of Hg species in natural waters and the analytical challenges associated with them are discussed. Approaches for sample collection and storage, pre-concentration, separation, and detection are critically compared. The review covers well established methods for total mercury determination and identifies new approaches that offer advantages such as ease of use and reduced risk of contamination. Pre-concentration and separation techniques for Hg speciation are divided into chromatographic and non-chromatographic methods. Derivatisation methods and the coupling of pre-concentration and/or separation methods to suitable detection techniques are also discussed. Techniques for sample pre-treatment, pre-concentration, separation, and quantification of Hg species, together with examples of total Hg determination and Hg speciation analysis in different natural (non-spiked) waters are summarised in tables, with a focus on applications from the last decade.

  18. A molecular-gap device for specific determination of mercury ions

    PubMed Central

    Guo, Zheng; Liu, Zhong-Gang; Yao, Xian-Zhi; Zhang, Kai-Sheng; Chen, Xing; Liu, Jin-Huai; Huang, Xing-Jiu

    2013-01-01

    Specific determination/monitoring of trace mercury ions (Hg2+) in environmental water is of significant importance for drinking safety. Complementarily to conventional inductively coupled plasma mass spectrometry and atomic emission/absorption spectroscopy, several methods, i.e., electrochemical, fluorescent, colorimetric, and surface enhanced Raman scattering approaches, have been developed recently. Despite great success, many inevitably encounter the interferences from other metal ions besides the complicated procedures and sophisticated equipments. Here we present a molecular-gap device for specific determination of trace Hg2+ in both standardized solutions and environmental samples based on conductivity-modulated glutathione dimer. Through a self-assembling technique, a thin film of glutathione monolayer capped Au nanoparticles is introduced into 2.5 μm-gap-electrodes, forming numerous double molecular layer gaps. Notably, the fabricated molecular-gap device shows a specific response toward Hg2+ with a low detection limit actually measured down to 1 nM. Theoretical calculations demonstrate that the specific sensing mechanism greatly depends on the electron transport ability of glutathione dimer bridged by heavy metal ions, which is determined by its frontier molecular orbital, not the binding energy. PMID:24178058

  19. A molecular-gap device for specific determination of mercury ions

    NASA Astrophysics Data System (ADS)

    Guo, Zheng; Liu, Zhong-Gang; Yao, Xian-Zhi; Zhang, Kai-Sheng; Chen, Xing; Liu, Jin-Huai; Huang, Xing-Jiu

    2013-11-01

    Specific determination/monitoring of trace mercury ions (Hg2+) in environmental water is of significant importance for drinking safety. Complementarily to conventional inductively coupled plasma mass spectrometry and atomic emission/absorption spectroscopy, several methods, i.e., electrochemical, fluorescent, colorimetric, and surface enhanced Raman scattering approaches, have been developed recently. Despite great success, many inevitably encounter the interferences from other metal ions besides the complicated procedures and sophisticated equipments. Here we present a molecular-gap device for specific determination of trace Hg2+ in both standardized solutions and environmental samples based on conductivity-modulated glutathione dimer. Through a self-assembling technique, a thin film of glutathione monolayer capped Au nanoparticles is introduced into 2.5 μm-gap-electrodes, forming numerous double molecular layer gaps. Notably, the fabricated molecular-gap device shows a specific response toward Hg2+ with a low detection limit actually measured down to 1 nM. Theoretical calculations demonstrate that the specific sensing mechanism greatly depends on the electron transport ability of glutathione dimer bridged by heavy metal ions, which is determined by its frontier molecular orbital, not the binding energy.

  20. Improvement of sensitivity of electrolyte cathode discharge atomic emission spectrometry (ELCAD-AES) for mercury using acetic acid medium.

    PubMed

    Shekhar, R

    2012-05-15

    A method has been developed to improve the sensitivity of the electrolyte cathode discharge atomic emission spectrometry (ELCAD-AES) for mercury determination. Effects of various low molecular weight organic solvents at different volume percentages as well as at different acid molarities on the mercury signal were investigated using ELCAD-AES. The addition of few percent of organic solvent, acetic acid produced significant enhancement in mercury signal. Acetic acid of 5% (v/v) with the 0.2M acidity has been found to give 500% enhancement for mercury signal in flow injection mode. Under the optimized parameters the repeatability, expressed as the percentage relative standard deviation of spectral peak area for mercury with 5% acetic acid was found to be 10% for acid blank solution and 5% for 20 ng/mL mercury standard based on multiple measurements with a multiple sample loading in flow injection mode. Limit of detection of this method was determined to be 2 ng/mL for inorganic mercury. The proposed method has been validated by determining mercury in certified reference materials, Tuna fish (IAEA-350) and Aquatic plant (BCR-060). Accuracy of the method for the mercury determination in the reference materials has been found to be between 3.5% and 5.9%. This study enhances the utility of ELCAD-AES for various types of biological and environmental materials to quantify total mercury at very low levels.

  1. New method to determine the optical rotatory dispersion of inorganic crystals applied to some samples of Carpathian Quartz.

    PubMed

    Dimitriu, Dan Gheorghe; Dorohoi, Dana Ortansa

    2014-10-15

    A new method to determine the optical rotatory dispersion (ORD) in the visible range, based on a channeled spectrum obtained with a uniax inorganic crystal introduced between two crossed polarizers with its optical axis parallel to the light propagation direction is detailed in this paper. When the studied inorganic crystals are transparent, this method permits the estimation of the optical rotatory dispersion in the visible range, for which the cheap polarizers are available. The speed of the measurements is very high, because the estimations are made from the channeled spectrum obtained for a single arrangement of the optical components. By using a computer, ORD is quickly determined for the visible range. The results obtained by this method for some Carpathian Quartz samples are consistent with those from literature. The proposed method can be also applied in UV and IR spectral ranges, when the anisotropic layers are transparent and the linearly polarized radiations can be obtained.

  2. Mercury and cadmium uptake from seawater and from food by the Norway lobster Nephrops norvegicus

    SciTech Connect

    Canli, M.; Furness, R.W.

    1995-05-01

    Norway lobsters, nephrops norvegicus, were fed on a mercury- and cadmium-rich diet for up to 50 d or were exposed to sublethal concentrations of organic mercury, inorganic mercury, or cadmium in seawater for 30 d. Cadmium taken up from seawater accumulated mainly in the hepatopancreas and gill, while it accumulated mainly in the hepatopancreas after feeding. Both organic and inorganic mercury taken up from seawater accumulated mainly in the gill, while highest concentrations were found in the hepatopancreas after the feeding experiment. Accumulation of organic mercury was higher than that of inorganic mercury. Although all treatments resulted in the accumulation of mercury and cadmium from seawater and food, tissue distribution of metals differed significantly among treatments. Distributions of organic and inorganic mercury also varied among tissues after uptake from seawater, with organic mercury being more evenly distributed among tissues than inorganic mercury, the latter being found predominantly in the gill.

  3. COULOMETRIC DETERMINATION OF TOTAL SULFUR AND REDUCED INORGANIC SULFUR FRACTIONS IN ENVIRONMENTAL SAMPLES

    EPA Science Inventory

    Evaluation of the solid-phase partitioning of sulfur is frequently an important analytical component of risk assessments at hazardous waste sites because minerals containing reduced-sulfur can significantly affect the transport and fate of organic and inorganic contaminants in na...

  4. METABOLISM AS A DETERMINING FACTOR IN ACUTE AND CHRONIC TOXICITY OF INORGANIC ARSENIC

    EPA Science Inventory

    The metabolism of inorganic arsenic (iAs) in humans involves reduction of As(V)-species to trivalency and oxidative methylation of As(III)-species. In this pathway, iAs is converted to methylarsenic (MAs) and dimethyl arsenic (DMAs) metabolites that contain As(III) or As(V). Rec...

  5. Incorporation of inorganic mercury (Hg2+) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: the role of different plankton size fractions and species assemblages

    USGS Publications Warehouse

    Soto Cárdenas, Carolina; Diéguez, Maria C.; Ribeiro Guevara, Sergio; Marvin-DiPasquale, Mark; Queimaliños, Claudia P.

    2014-01-01

    In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg2+) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg2+ by four plankton fractions (picoplankton: 0.2–2.7 μm; pico + nanoplankton: 0.2–20 μm; microplankton: 20–50 μm; and mesoplankton: 50–200 μm) obtained from four Andean Patagonian lakes, using the radioisotope 197Hg2+. Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg2+ in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico + nanoplankton play a central role leading the incorporation of Hg2+ in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg2+ by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria–nanoflagellates–crustaceans; bacteria–ciliates–crustaceans; endosymbiotic algae–ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg2+ observed in all the plankton fractions.

  6. Incorporation of inorganic mercury (Hg²⁺) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: the role of different plankton size fractions and species assemblages.

    PubMed

    Soto Cárdenas, Carolina; Diéguez, Maria C; Ribeiro Guevara, Sergio; Marvin-DiPasquale, Mark; Queimaliños, Claudia P

    2014-10-01

    In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg(2+)) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg(2+) by four plankton fractions (picoplankton: 0.2-2.7 μm; pico+nanoplankton: 0.2-20 μm; microplankton: 20-50 μm; and mesoplankton: 50-200 μm) obtained from four Andean Patagonian lakes, using the radioisotope (197)Hg(2+). Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg(2+) in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico+nanoplankton play a central role leading the incorporation of Hg(2+) in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg(2+) by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria-nanoflagellates-crustaceans; bacteria-ciliates-crustaceans; endosymbiotic algae-ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg(2+) observed in all the plankton fractions.

  7. Determination of mercury complexation in coastal and estuarine waters using competitive ligand exchange method.

    PubMed

    Han, Seunghee; Gill, Gary A

    2005-09-01

    While many studies have examined Hg(II) binding ligand in natural dissolved organic matter, determined ligand concentrations far exceed natural Hg(II) concentrations. This ligand class may not influence natural Hg(II) complexation, given the reverse relation between ligand concentration and metal-ligand binding strength. This study used a new competing ligand, thiosalicylic acid, in a competitive ligand exchange method in which water-toluene extraction was used to determine extremely strong Hg(II) binding sites in estuarine and coastal waters (dissolved [Hg] = 0.5-8 pM). Thiosalicylic acid competition lowered the detection limit of Hg(II) complexing ligand by 2 orders of magnitude from values found by previous studies; the determined Hg(II) complexing ligand ranged from 13 to 103 pM. The logarithmic conditional stability constants between Hg(II) and Hg(II) complexing ligand (Kcond' = [HgL]/([Hg2+][L']), [L'] = total [L] - [HgL]) ranged from 26.5 to 29.0. Applying the same method for chloride competition detected another class of ligand that is present from 0.5 to 9.6 nM with log conditional stability constants ranging from 23.1 to 24.4. A linear relationship was observed between the log conditional stability constant and log Hg(II) complexing ligand concentration, supporting the hypothesis that Hg(II) binding ligand should be characterized as a series or continuum of binding sites on natural dissolved organic matter. Calculating Hg(II) complexation using the conditional stability constants and ligand concentrations determined in this study indicates that >99% of the dissolved mercury is complexed by natural ligand associated with dissolved organic matter in estuarine and coastal waters of Galveston Bay, Texas.

  8. DETERMINATION OF TOTAL MERCURY IN FISH TISSUES USING PYROLYSIS ATOMIC ABSORPTION SPECTROMETRY WITH GOLD AMALGAMATION

    EPA Science Inventory

    A simple and rapid procedure for measuring total mercury in fish tissues is evaluated and
    compared with conventional techniques. Using an automated instrument incorporating combustion, preconcentration by amalgamation with gold, and atomic absorption spectrometry (AAS), mill...

  9. A BIOPSY PROCEDURE FOR DETERMINING FILET AND PREDICTING WHOLE-FISH MERCURY CONCENTRATION

    EPA Science Inventory

    Although mercury contamination of fish is a widespread phenomenon, its regional evaluation is hindered by the reluctance of permitting agencies to grant collection permits, securing adequate freezer space, and processing whole, large fish or filets. We evaluated Hg concentration...

  10. Determination of total mercury in environmental and biological samples by flow injection cold vapour atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Murphy, James; Jones, Phil; Hill, Steve J.

    1996-12-01

    A simple and accurate method has been developed for the determination of total mercury in environmental and biological samples. The method utilises an off-line microwave digestion stage followed by analysis using a flow injection system with detection by cold vapour atomic absorption spectrometry. The method has been validated using two certified reference materials (DORM-1 dogfish and MESS-2 estuarine sediment) and the results agreed well with the certified values. A detection limit of 0.2 ng g -1 Hg was obtained and no significant interference was observed. The method was finally applied to the determination of mercury in river sediments and canned tuna fish, and gave results in the range 0.1-3.0 mg kg -1.

  11. Determination of mercury in coal by isotope dilution cold-vapor generation inductively coupled plasma mass spectrometry.

    PubMed

    Long, Stephen E; Kelly, W Robert

    2002-04-01

    A method based on isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICPMS) has been developed for high-accuracy determinations of mercury in bituminous and sub-bituminous coals. A closed-system digestion process employing a Carius tube is used to completely oxidize the coal matrix and chemically equilibrate the mercury in the sample with a 201Hg isotopic spike. The digestates are diluted with high-purity quartz-distilled water, and the mercury is released as a vapor by reduction with tin(II) chloride. Measurements of 201Hg/202Hg isotope ratios are made using a quadrupole ICPMS system in time-resolved analysis mode. The new method has some significant advantages over existing methods. The instrument detection limit is less than 1 pg/mL. The average blank (n = 17) is 30 pg, which is roughly 1 order of magnitude lower than the equivalent microwave digestion procedure. The detection limit in coal is blank limited and is approximately 40 pg/g. Memory effects are very low. The relative reproducibility of the analytical measurements is approximately 0.5% for mercury concentrations in the range 10-150 ng/g. The method has been used to measure mercury concentrations in six coal reference materials, SRM 1632b (77.4 ng/g), SRM 1632c (94.3 ng/g), BCR 40 (433.2 ng/g), BCR 180 (125.0 ng/g), BCR 181 (135.8 ng/g), and SARM 20 (252.6 ng/g), as well as a coal fly ash, SRM 1633b (143.1 ng/g). The method is equally applicable to other types of fossil fuels including both crude and refined oils.

  12. Anodic stripping voltammetric determination of cadmium using a "mercury free" indium film electrode.

    PubMed

    Anandhakumar, Sukeri; Mathiyarasu, Jayaraman; Phani, Kanala Lakshimi Narasimha

    2013-10-07

    In this work, the determination of cadmium has been attempted using an indium film electrode in the presence of bromide ions as an additive, for the first time. The electrode was prepared in situ on a glassy carbon substrate and employed in combination with square wave anodic stripping voltammetry. The purpose of having bromide ions is to enhance the analytical value of cadmium detection. In the absence of bromide ions, cadmium stripping peaks coalesce with indium and it is difficult to resolve for analytical purposes. The addition of bromide ions strongly influences the peak separation, thanks to the complex-forming characteristics of cadmium with bromide ions. Several key operational parameters influencing the electroanalytical response of indium modified electrodes were examined and optimized, such as deposition potential, pH, bromide ion and indium concentration. The indium modified electrode exhibited well-defined, separated stripping signals and revealed good linear behavior in the examined concentration range from 1 to 25 ng ml(-1). The present method shows a low detection limit value of 0.36 ng ml(-1). These results suggest that the proposed electrode contributes to the wider applicability of electrochemical stripping techniques in connection with "mercury-free" electrodes.

  13. Determination of mercury in hair: Comparison between gold amalgamation-atomic absorption spectrometry and mass spectrometry.

    PubMed

    Domanico, Francesco; Forte, Giovanni; Majorani, Costanza; Senofonte, Oreste; Petrucci, Francesco; Pezzi, Vincenzo; Alimonti, Alessandro

    2016-09-29

    Mercury is a heavy metal that causes serious health problems in exposed subjects. The most toxic form, i.e., methylmercury (MeHg), is mostly excreted through human hair. Numerous analytical methods are available for total Hg analysis in human hair, including cold vapour atomic fluorescence spectrometry (CV-AFS), inductively coupled plasma mass spectrometry (ICP-MS) and thermal decomposition amalgamation atomic absorption spectrometry (TDA-AAS). The aim of the study was to compare the TDA-AAS with the ICP-MS in the Hg quantification in human hair. After the washing procedure to minimize the external contamination, from each hair sample two aliquots were taken; the first was used for direct analysis of Hg by TDA-AAS and the second was digested for Hg determination by the ICP-MS. Results indicated that the two data sets were fully comparable (median; TDA-AAS, 475ngg(-1); ICP-MS, 437ngg(-1)) and were not statistically different (Mann-Whitney test; p=0.44). The two techniques presented results with a good coefficient of correlation (r=0.94) despite different operative ranges and method limits. Both techniques satisfied internal performance requirements and the parameters for method validation resulting sensitive, precise and reliable. Finally, the use of the TDA-AAS can be considered instead of the ICP-MS in hair analysis in order to reduce sample manipulation with minor risk of contamination, less time consuming due to the absence of the digestion step and cheaper analyses.

  14. Determination of total mercury in seafood and other protein-rich products

    SciTech Connect

    Landi, S.; Fagioli, F.; Locatelli, C.

    1992-11-01

    A previously developed wet-digestion method for the determination of total mercury in plants by cold vapor atomic absorption spectroscopy (CVAAS) was extended to the analysis of seafood and other products rich in proteins. Oxidation of matrixes is accomplished by K{sub 2}Cr{sub 2}O{sub 7} in the presence of diluted H{sub 2}SO{sub 4}; a simple air condenser is used to reflux vapors released from the boiling mixture. The original procedure (A) and 2 modifications (B and C), which differ with respect to the mode of acidification and/or digestion time and the types of condensers used, were compared for precision and accuracy by means of National Institute of Standards and Technology Research Material 50 Albacore Tuna and proved to be reliable (Hg present, 0.95{plus_minus}0.1 {mu}g/g; Hg found, 0.97 {plus_minus} 0.029 {mu}g/g [A], 0.98 {plus_minus} 0.018 {mu}g/g [B], and 0.94 {plus_minus} 0.025 {mu}g/g [C]). The modified procedures were tested further in Hg recovery experiments on a variety of biological matrixes with different spiking substances and again showed good analytical characteristics (overall average recoveries = 98 {plus_minus} 5.1% for seafood and 100 {plus_minus} 3.6 for protein-rich baby foods). 22 refs., 1 fig., 5 tabs.

  15. Flotation-spectrophotometric determination of mercury in water samples using iodide and ferroin.

    PubMed

    Hosseini, Mohammad Saeid; Hashemi-Moghaddam, Hamid

    2004-10-01

    This paper describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of trace amounts of mercury. The method is based on the flotation of an ion-associate of HgI4(2-) and ferroin between aqueous and n-heptane interface at pH 5. The ion-associate was then separated and dissolved in acetonitrile to measure its absorbance. Quantitative flotation of the ion-associate was achieved when the volume of the water sample containing Hg(II) was varied over 50 - 800 ml. Beer's law was obeyed over the concentration range of 3.2 x 10(-8) - 9.5 x 10(-7) mol l(-1) with an apparent molar absorptivity of 1 x 10(6) l mol(-1) cm(-1) for a 500 ml aliquot of the water sample. The detection limit (n = 25) was 6.2 x 10(-9) mol l(-1), and the RSD (n = 5) for 3.19 x 10(-7) mol l(-1) of Hg(II) was 1.9%. A notable advantage of the method is that the determination of Hg(II) is free from the interference of the almost all cations and anions found in the environmental and waste water samples. The determination of Hg(II) in tap, synthetic waste, and seawater samples was carried out by the present method and a well-established method of extraction with dithizone. The results were satisfactorily comparable so that the applicability of the proposed method was confirmed in encountering with real samples.

  16. Allozyme genotype in mosquitofish, Gambusia holbrooki, during mercury exposure: Temporal stability, concentration effects and field verification

    SciTech Connect

    Heagler, M.G. Rutgers, The State Univ. of New Jersey, New Brunswick )

    1993-02-01

    Genotype frequencies at nine enzyme loci were examined in a population of mosquito fish, Gambusia holbrooki, during acute inorganic mercury exposure at three concentration. Genotype at one locus, glucose phosphate isomerase-2 (Gpi-2), was correlated with time to death (TTD) at the low mercury concentration, but genotypes at none of the nine loci were related to TTD at the medium or the high mercury concentration. A survey of mosquitofish from a mercury-contaminated canal was undertaken to determine if the results of laboratory exposures could be used to predict accurately the genetic profile of mercury-contaminated field populations. Mosquitofish collected from the contaminated canal had a significantly lower frequency of the Gpi-2[sup 38] allele than mosquitofish collected from the adjacent noncontaminated river. The Gpi-2 allozymes may be useful as an indicator of pollutant stress if used in conjunction with a thorough understanding of the structure and history of the population.

  17. Method and apparatus for sampling atmospheric mercury

    DOEpatents

    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.

  18. OPTIMIZATION OF VOLTAMMETRIC METHODS FOR AN IN SITU DETERMINATION OF TOTAL SULFIDE IN ANOXIC POREWATER USING A MERCURY PLATED GOLD ELECTRODE

    EPA Science Inventory

    Voltammetric methods for determination of total sulfide concentrations in anoxic sediments utilizing a previously described [1] gold-based mercury amalgam microelectrode were optimized. Systematic studies in NaCl (supporting electrolyte) and porewater indicate variations in ionic...

  19. Anodic stripping voltammetric determination of mercury using multi-walled carbon nanotubes film coated glassy carbon electrode.

    PubMed

    Yi, Hongchao

    2003-10-01

    An electrochemical method for the determination of trace levels of mercury based on a multi-walled carbon nanotubes (MWNT) film coated glassy carbon electrode (GCE) is described. In 0.1 mol L(-1) HCl solution containing 0.02 mol L(-1) KI, Hg(2+) was firstly preconcentrated at the MWNT film and then reduced at -0.60 V. During the anodic potential sweep, reduced mercury was oxidized, and then a sensitive and well-defined stripping peak at about -0.20 V appeared. Under identical conditions, a MWNT film coated GCE greatly enhances the stripping peak current of mercury in contrast to a bare GCE. Low concentrations of I(-) remarkably improve the determining sensitivity, since this increases the accumulation efficiency of Hg(2+) at the MWNT film coated GCE. The stripping peak current is proportional to the concentration of Hg(2+) over the range 8 x 10(-10)-5 x 10(-7) mol L(-1). The lowest detectable concentration of Hg(2+) is 2 x 10(-10) mol L(-1) at 5 min accumulation. The relative standard deviation (RSD) at 1 x 10(-8) mol L(-1) Hg(2+) was about 6% ( n=10). By using this proposed method, Hg(2+) in some water samples was determined, and the results were compared with those obtained by atomic absorption spectrometry (AAS). The two results are similar, suggesting that the MWNT-film coated GCE has great potential in practical analysis.

  20. Mercury(II) and methyl mercury determinations in water and fish samples by using solid phase extraction and cold vapour atomic absorption spectrometry combination.

    PubMed

    Tuzen, Mustafa; Karaman, Isa; Citak, Demirhan; Soylak, Mustafa

    2009-07-01

    A method has been developed for mercury(II) and methyl mercury speciation on Staphylococcus aureus loaded Dowex Optipore V-493 micro-column in the presented work, by using cold vapour atomic absorption spectrometry. Selective and sequential elution with 0.1 molL(-1) HCl for methyl mercury and 2 molL(-1) HCl for mercury(II) were performed at the pH range of 2-6. Optimal analytical conditions including pH, amounts of biosorbent, sample volumes were investigated. The detection limits of the analytes were 2.5 ngL(-1) for Hg(II) and 1.7 ngL(-1) for methyl mercury. The capacity of biosorbent for mercury(II) and methyl mercury was 6.5 and 5.4 mgg(-1), respectively. The validation of the presented procedure is performed by the analysis of standard reference material. The speciation procedure established was successfully applied to the speciation of mercury(II) and methyl mercury in natural water and microwave digested fish samples.

  1. New preconditioning strategy for the determination of inorganic anions with capillary zone electrophoresis using indirect UV detection.

    PubMed

    Raber, G; Greschonig, H

    2000-08-25

    It is widely accepted that preconditioning procedures are indispensable in capillary electrophoresis in order to achieve reproducibility of migration times and peak areas. Several preconditioning strategies have been employed for electrophoretic determinations of inorganic anions using indirect UV detection including simple flushing with buffer or alkaline or acid pre-rinsing followed by flushing with electrolyte. We investigated the influence of various preconditioning strategies on the reproducibility of migration times and peak areas of inorganic anions. The electrolyte systems for indirect UV detection were based on pyromellitic acid and chromic acid respectively as UV absorbing probes and hexamethonium hydroxide as electroosmatic flow modifier. Preconditioning agents under investigation were electrolyte buffer, NaOH, HCl and the free acids of the UV absorbing probes. Investigations showed that reproducibility of migration times and peak areas can be significantly improved by acid pre-rinsing using the corresponding acid of the UV absorbing probes compared to preconditioning by flushing the capillary with buffer. In contrast to acid pre-rinsing using hydrochloric acid no interfering signals within the migration time window of inorganic anions under investigation can be observed. The optimized preconditioning procedure yields relative standard deviations of migration times less than 0.25% (n = 10). Relative standard deviations of corrected peak areas were below 5% applying acid preconditioning using pyromellitic acid.

  2. Dose-response analysis indicating time-dependent neurotoxicity caused by organic and inorganic mercury-Implications for toxic effects in the developing brain.

    PubMed

    Pletz, Julia; Sánchez-Bayo, Francisco; Tennekes, Henk A

    2016-03-10

    A latency period preceding neurotoxicity is a common characteristic in the dose-response relationship induced by organic mercury. Latency periods have typically been observed with genotoxicants in carcinogenesis, with cancer being manifested a long time after the initiating event. These observations indicate that even a very small dose may cause extensive adverse effects later in life, so the toxicity of the genotoxic compound is dose and time-dependent. In children, methylmercury exposure during pregnancy (in utero) has been associated with delays in reaching developmental milestones (e.g., age at first walking) and decreases in intelligence, increasing in severity with increasing exposure. Ethylmercury exposure from thimerosal in some vaccines has been associated, in some studies, with autism and other neurological disorders in children. In this paper, we have examined whether dose-response data from in vitro and in vivo organic mercury toxicity studies fit the Druckrey-Küpfmüller equation c·t(n)=constant (c=exposure concentration, t=latency period), first established for genotoxic carcinogens, and whether or not irreversible effects are enhanced by time of exposure (n≥1), or else toxic effects are dose-dependent while time has only minor influence on the adverse outcome (n<1). The mode of action underlying time-dependent toxicity is irreversible binding to critical receptors causing adverse and cumulative effects. The results indicate that the Druckrey-Küpfmüller equation describes well the dose-response characteristics of organic mercury induced neurotoxic effects. This amounts to a paradigm shift in chemical risk assessment of mercurial compounds and highlights that it is vital to perform toxicity testing geared to investigate time-dependent effects.

  3. Sampling procedure and a radio-indicator study of mercury determination in whole blood by using an AMA 254 atomic absorption spectrometer.

    PubMed

    Spevácková, Vera; Korunová, Vlasta; Cejchanová, Mája; Vobecký, Miloslav

    2004-09-01

    A sampling procedure appropriate for the determination of mercury in whole blood was tested by using both inactive controls and a 197Hg mercury radio-indicator. To exclude the influence of the instrumental device (an AMA 254 single-purpose mercury atomic absorption spectrometer) on the determination of mercury in whole blood, the function of the instrument was checked by using rat blood with metabolised 197Hg. The measurement procedure was found to be free of errors. However, the study showed that the material used for the sampling vessels is a crucial parameter for obtaining accurate analytical results. The stability of solutions and samples was tested towards polyethylene (PE) and polypropylene (PP) vessels. PE displayed a time-dependent increase in the mercury content both in the samples and in the blood control material. The probable cause of this increase was direct contamination from the material of the vessel and/or diffusion of mercury from the environment through the vessel walls related to a strong complexing affinity of the sample matrix. This assumption was confirmed by supplying the vessels with the complexing agent Na2EDTA (0.05 mol L(-1)). Commercial PP vessels for blood sampling (Sarstedt S-Monovette Metall Analytik) did not give rise to statistically significant variations in mercury content in the samples and blood control material over a 30-day period.

  4. Improved preparation of small biological samples for mercury analysis using cold vapor atomic absorption spectroscopy.

    PubMed

    Adair, B M; Cobb, G P

    1999-05-01

    Concentrations of mercury in biological samples collected for environmental studies are often less than 0.1 microgram/g. Low mercury concentrations and small organ sizes in many wildlife species (approximately 0.1 g) increase the difficulty of mercury determination at environmentally relevant concentrations. We have developed a digestion technique to extract mercury from small (0.1 g), biological samples at these relevant concentrations. Mean recoveries (+/- standard error) from validation trials of mercury fortified tissue samples using cold vapor atomic absorption spectroscopy for analysis ranged from 102 +/- 4.3% (2.5 micrograms/L, n = 15) to 108 +/- 1.4% (25 micrograms/L, n = 15). Recoveries of inorganic mercury were 99 +/- 5 (n = 19) for quality assurance samples analyzed during environmental evaluations conducted during a 24 month period. This technique can be used to determine total mercury concentrations of 60 ng Hg/g sample. Samples can be analyzed in standard laboratories in a short time, at minimal cost. The technique is versatile and can be used to determine mercury concentrations in several different matrices, limiting the time and expense of method development and validation.

  5. Determination of inorganic phosphorus in serum: Evaluation of three methods applied to the Technicon RA-1000 analyzer.

    PubMed

    Rubino, L; Catapano, V; Guerra, G

    1989-01-01

    We have evaluated three analytical methods for determining inorganic phosphorus in serum applied to the Technicon RA-I000 analyzer: a fully enzymatic colorimetric method based on the specific system purine nucleoside phosphorylase/xanthine oxidase coupled to an indicator colorimetric reaction similar to the Trinder reaction; a chemical method involving the direct UV measurement of the phosphomolybdate complex; and a chemical method with reduction of the phosphomolybdate complex to molybdenum blue. Experiments were performed to assess within-run and between-day precision, linearity, interference and correlation. The best performance characteristics were shown by the enzymatic colorimetric method and the phosphomolybdate UV method.

  6. Simple and accessible analytical methods for the determination of mercury in soil and coal samples.

    PubMed

    Park, Chul Hee; Eom, Yujin; Lee, Lauren Jong-Eun; Lee, Tai Gyu

    2013-09-01

    Simple and accessible analytical methods compared to conventional methods such as US EPA Method 7471B and ASTM-D6414 for the determination of mercury (Hg) in soil and coal samples are proposed. The new methods are consisted of fewer steps without the Hg oxidizing step consequently eliminating a step necessary to reduce excess oxidant. In the proposed methods, a Hg extraction is an inexpensive and accessible step utilizing a disposable test tube and a heating block instead of an expensive autoclave vessel and a specially-designed microwave. Also, a common laboratory vacuum filtration was used for the extracts instead of centrifugation. As for the optimal conditions, first, best acids for extracting Hg from soil and coal samples was investigated using certified reference materials (CRMs). Among common laboratory acids (HCl, HNO3, H2SO4, and aqua regia), aqua regia was most effective for the soil CRM whereas HNO3 was for the coal CRM. Next, the optimal heating temperature and time for Hg extraction were evaluated. The most effective Hg extraction was obtained at 120°C for 30min for soil CRM and at 70°C for 90min for coal CRM. Further tests using selected CRMs showed that all the measured values were within the allowable certification range. Finally, actual soil and coal samples were analyzed using the new methods and the US EPA Method 7473. The relative standard deviation values of 1.71-6.55% for soil and 0.97-12.11% for coal samples were obtained proving that the proposed methods were not only simple and accessible but also accurate.

  7. Development of a novel method for determination of mercury based on its inhibitory effect on horseradish peroxidase activity followed by monitoring the surface plasmon resonance peak of gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Khodaveisi, Javad; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Moghadam, Masoud Rohani; Hormozi-Nezhad, Mohammad Reza

    2016-01-01

    A highly sensitive and simple indirect spectrophotometric method has been developed for the determination of trace amounts of inorganic mercury (Hg2 +) in aqueous media. The method is based on the inhibitory effect of Hg2 + on the activity of horseradish peroxidase (HRP) in the oxidation of ascorbic acid by hydrogen peroxide followed by the reduction of Au3 + to Au-NPs by unreacted ascorbic acid and the measurement of the absorbance of localized surface plasmon resonance (LSPR) peak of gold nanoparticles (at 530 nm) which is directly proportional to the concentration of Hg2 +. Under the optimum conditions, the calibration curve was linear in the concentration range of 1-220 ng mL- 1. Limits of detection (LOD) and quantification (LOQ) were 0.2 and 0.7 ng mL- 1, respectively and the relative standard deviation at 100 ng mL- 1 level of Hg2 + was 2.6%. The method was successfully applied to the determination of mercury in different water samples.

  8. Voltammetric methods for determination and speciation of inorganic arsenic in the environment--a review.

    PubMed

    Mays, Douglas E; Hussam, Abul

    2009-07-30

    The measurement of inorganic arsenic in the environment has received considerable attention over the past 40+ years due to its toxicity and prevalence in drinking water. This paper provides an overview of voltammetric techniques used since 2001. More than fifty papers from refereed analytical chemistry journals on the speciation and measurement of inorganic arsenic (As(III) and As(V)) in practical and environmental samples are included. The present review shows that stripping voltammetry is a sensitive and inexpensive technique. The new approaches include development of novel measurement protocols through media variation, development and use of new boron doped diamond electrodes modified with metals, nano Au-modified electrodes on carbon or carbon nano-tubes, novel rotating disc and vibrating electrodes to enhance mass transfer, and modified Hg(l) and thin film Bi on carbon for cathodic stripping voltammetry are discussed. Although, majority of the papers were of exploratory in nature, the trend towards developing a commercial standalone instrument for field use is still in progress.

  9. [Simultaneous determination of three inorganic anions in food-grade lubricating oils by chromatography with suppressed conductivity detection].

    PubMed

    Zhang, Liyuan; Fei, Xudong; Qiu, Feng; Lin, Miao

    2015-02-01

    An ion chromatographic (IC) method with suppressed conductivity detection was developed for the simultaneous determination of Cl-, NO3(-), SO(2-)(4) in food-grade lubricating oils. After ultrasonic extraction with 50% (v/v) methanol aqueous solution and centrifugation, the sample in aqueous phase was purified with 0. 22 µm hybrid fiber membranes, then analyzed by IC using 15 mmol/L KOH solution as eluent, and detected by a suppressed conductivity detector. Effects of the concentration and flow rate of the eluent, and the concentration of the methanol aqueous solution on the detection of the three anions were investigated. Under the optimized separation conditions, the three anions were separated completely and the system peaks didn't interfere with the determination. The calibration curves showed good linearity (R2> 0. 999) in the range of 0. 10-20. 00 mg/L. The limits of detection (LODs, S/N= 3) were 0. 01 - 0. 03 mg/kg. The average recoveries of Cl-, NO(-)3, SO(2-)4 anions were 90. 0% - 103. 6% with the relative standard deviations (RSDs) of 2. 8% - 5. 7%. This method avoids the time-consuming pretreatment process to burn or ash the oil phase matrix, and can determine the amounts of three inorganic anions (Cl-, NO(-)3, SO(2-)(4)) in food-grade lubricating oils fast and accurately. It is suitable for simultaneously separating and detecting trace inorganic anions in lubricating oils or other oil products.

  10. Mercury and gold concentrations of highly polluted environmental samples determined using prompt gamma-ray analysis and instrument neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Osawa, Takahito; Hatsukawa, Yuichi; Appel, Peter W. U.; Matsue, Hideaki

    2011-04-01

    The authors have established a method of determining mercury and gold in severely polluted environmental samples using prompt gamma-ray analysis (PGA) and instrumental neutron activation analysis (INAA). Since large amounts of mercury are constantly being released into the environment by small-scale gold mining in many developing countries, the mercury concentration in tailings and water has to be determined to mitigate environmental pollution. Cold-vapor atomic absorption analysis, the most pervasive method of mercury analysis, is not suitable because tailings and water around mining facilities have extremely high mercury concentrations. On the other hand, PGA can determine high mercury concentrations in polluted samples as it has an appropriate level of sensitivity. Moreover, gold concentrations can be determined sequentially by using INAA after PGA. In conclusion, the analytical procedure established in this work using PGA and INAA is the best way to evaluate the degree of pollution and the tailing resource value. This method will significantly contribute to mitigating problems in the global environment.

  11. Determination of Mercury in Aqueous and Geologic Materials by Continuous Flow-Cold Vapor-Atomic Fluorescence Spectrometry (CVAFS)

    USGS Publications Warehouse

    Hageman, Philip L.

    2007-01-01

    New methods for the determination of total mercury in geologic materials and dissolved mercury in aqueous samples have been developed that will replace the methods currently (2006) in use. The new methods eliminate the use of sodium dichromate (Na2Cr2O7 ?2H2O) as an oxidizer and preservative and significantly lower the detection limit for geologic and aqueous samples. The new methods also update instrumentation from the traditional use of cold vapor-atomic absorption spectrometry to cold vapor-atomic fluorescence spectrometry. At the same time, the new digestion procedures for geologic materials use the same size test tubes, and the same aluminum heating block and hot plate as required by the current methods. New procedures for collecting and processing of aqueous samples use the same procedures that are currently (2006) in use except that the samples are now preserved with concentrated hydrochloric acid/bromine monochloride instead of sodium dichromate/nitric acid. Both the 'old' and new methods have the same analyst productivity rates. These similarities should permit easy migration to the new methods. Analysis of geologic and aqueous reference standards using the new methods show that these procedures provide mercury recoveries that are as good as or better than the previously used methods.

  12. Determination of toxic elements (mercury, cadmium, lead, tin and arsenic) in fish and shellfish samples. Risk assessment for the consumers.

    PubMed

    Olmedo, P; Pla, A; Hernández, A F; Barbier, F; Ayouni, L; Gil, F

    2013-09-01

    Although fish intake has potential health benefits, the presence of metal contamination in seafood has raised public health concerns. In this study, levels of mercury, cadmium, lead, tin and arsenic have been determined in fresh, canned and frozen fish and shellfish products and compared with the maximum levels currently in force. In a further step, potential human health risks for the consumers were assessed. A total of 485 samples of the 43 most frequently consumed fish and shellfish species in Andalusia (Southern Spain) were analyzed for their toxic elements content. High mercury concentrations were found in some predatory species (blue shark, cat shark, swordfish and tuna), although they were below the regulatory maximum levels. In the case of cadmium, bivalve mollusks such as canned clams and mussels presented higher concentrations than fish, but almost none of the samples analyzed exceeded the maximum levels. Lead concentrations were almost negligible with the exception of frozen common sole, which showed median levels above the legal limit. Tin levels in canned products were far below the maximum regulatory limit, indicating that no significant tin was transferred from the can. Arsenic concentrations were higher in crustaceans such as fresh and frozen shrimps. The risk assessment performed indicated that fish and shellfish products were safe for the average consumer, although a potential risk cannot be dismissed for regular or excessive consumers of particular fish species, such as tuna, swordfish, blue shark and cat shark (for mercury) and common sole (for lead).

  13. Plasma-based determination of inorganic contaminants in waste of electric and electronic equipment after microwave-induced combustion

    NASA Astrophysics Data System (ADS)

    Mello, Paola A.; Diehl, Lisarb O.; Oliveira, Jussiane S. S.; Muller, Edson I.; Mesko, Marcia F.; Flores, Erico M. M.

    2015-03-01

    A systematic study was performed for the determination of inorganic contaminants in polymeric waste from electrical and electronic equipment (EEE) for achieving an efficient digestion to minimize interferences in determination using plasma-based techniques. The determination of As, Br, Cd, Co, Cr, Cu, Ni, Pb, Sb, and Zn by inductively coupled plasma mass spectrometry (ICP-MS) and also by inductively coupled plasma optical emission spectrometry (ICP OES) was carried out after digestion using microwave-induced combustion (MIC). Arsenic and Hg were determined by flow-injection chemical vapor generation inductively coupled plasma mass spectrometry (FI-CVG-ICP-MS). Dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) with ammonia was also used for Cr determination. The suitability of MIC for digestion of sample masses up to 400 mg was demonstrated using microcrystalline cellulose as aid for combustion of polymers from waste of EEEs that usually contain flame retardants that impair the combustion. The composition and concentration of acid solutions (HNO3 or HNO3 plus HCl) were evaluated for metals and metalloids and NH4OH solutions were investigated for Br absorption. Accuracy was evaluated by comparison of results with those obtained using high pressure microwave-assisted wet digestion (HP-MAWD) and also by the analysis of certified reference material (CRM) of polymer (EC680k-low-density polyethylene). Bromine determination was only feasible using digestion by MIC once losses were observed when HP-MAWD was used. Lower limits of detection were obtained for all analytes using MIC (from 0.005 μg g- 1 for Co by ICP-MS up to 3.120 μg g-1 for Sb by ICP OES) in comparison to HP-MAWD due to the higher sample mass that can be digested (400 mg) and the use of diluted absorbing solutions. The combination of HNO3 and HCl for digestion showed to be crucial for quantitative recovery of some elements, as Cr and Sb. In addition, suitable agreement of Cr to

  14. Use of naturally occurring mercury to determine the importance of cutthroat trout to Yellowstone grizzly bears

    USGS Publications Warehouse

    Felicetti, L.A.; Schwartz, C.C.; Rye, R.O.; Gunther, K.A.; Crock, J.G.; Haroldson, M.A.; Waits, L.; Robbins, C.T.

    2004-01-01

    Spawning cutthroat trout (Oncorhynchus clarki (Richardson, 1836)) are a potentially important food resource for grizzly bears (Ursus arctos horribilis Ord, 1815) in the Greater Yellowstone Ecosystem. We developed a method to estimate the amount of cutthroat trout ingested by grizzly bears living in the Yellowstone Lake area. The method utilized (i) the relatively high, naturally occurring concentration of mercury in Yellowstone Lake cutthroat trout (508 ± 93 ppb) and its virtual absence in all other bear foods (6 ppb), (ii) hair snares to remotely collect hair from bears visiting spawning cutthroat trout streams between 1997 and 2000, (iii) DNA analyses to identify the individual and sex of grizzly bears leaving a hair sample, (iv) feeding trials with captive bears to develop relationships between fish and mercury intake and hair mercury concentrations, and (v) mercury analyses of hair collected from wild bears to estimate the amount of trout consumed by each bear. Male grizzly bears consumed an average of 5 times more trout/kg bear than did female grizzly bears. Estimated cutthroat trout intake per year by the grizzly bear population was only a small fraction of that estimated by previous investigators, and males consumed 92% of all trout ingested by grizzly bears.

  15. Structure of Mercury's Global Magnetic Field Determined from MESSENGER Orbital Observations

    NASA Astrophysics Data System (ADS)

    Anderson, B. J.; Johnson, C. L.; Korth, H.; Purucker, M. E.; Winslow, R. M.; Slavin, J. A.; Solomon, S. C.; McNutt, R. L.; Raines, J. M.; Zurbuchen, T.

    2011-12-01

    On 18 March 2011, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was inserted into a near-polar orbit about Mercury with a periapsis altitude of 200 km, an inclination of 82.5°, an apoapsis altitude of 15,300 km, and nominal orbit period of 12 hours. Magnetometer (MAG) data acquired since 23 March provide multiple circuits in solar local time and planetary longitude and yield extensive coverage of the planetary magnetic field sufficient to resolve the dominant magnetic fields of internal and external origin. Plasma pressures exceeding the magnetic pressure are commonly found within ±30° latitude of the equator and complicate solutions for the planetary field that use conventional spherical harmonic analysis. However, because the planetary field constrains the locations of external currents (e.g., the magnetopause and tail currents) to be symmetric about the magnetic equator, the location of that equator can be identified from the geometry of the magnetic field without the need to correct for local plasma pressures and external currents. We identify Mercury's magnetic equator from the orbital positions at which the cylindrical radial magnetic field component vanishes and find that the magnetic equator is offset north of the geographic equator by 484 ± 11 km. With this offset for the dipole we then analyze the tilt, position, and intensity of the best-fit dipole moment and find that the global planetary field is best represented as a southward-directed dipole, centered on the spin axis, tilted from that axis by less than 2.5°, and having a moment of 195 ± 10 nT-RM3, where RM is Mercury's radius. Mercury's axially symmetric but equatorially asymmetric field may imply lateral variations in heat flow at the planet's core-mantle boundary. This solution provides the basis for defining Mercury-solar-magnetospheric coordinates used to order observations of Mercury's magnetosphere, constructing a model for the magnetopause and

  16. Flood regime and leaf fall determine soil inorganic nitrogen dynamics in semiarid riparian forests.

    PubMed

    Shah, J J Follstad; Dahm, C N

    2008-04-01

    Flow regulation has reduced the exchange of water, energy, and materials between rivers and floodplains, caused declines in native plant populations, and advanced the spread of nonnative plants. Naturalized flow regimes are regarded as a means to restore degraded riparian areas. We examined the effects of flood regime (short [SIFI] vs. long [LIFI] inter-flood interval) on plant community and soil inorganic nitrogen (N) dynamics in riparian forests dominated by native Populus deltoides var. wislizenii Eckenwalder (Rio Grande cottonwood) and nonnative Tamarix chinensis Lour. (salt cedar) along the regulated middle Rio Grande of New Mexico. The frequency of inundation (every 2-3 years) at SIFI sites better reflected inundation patterns prior to the closure of an upstream dam relative to the frequency of inundation at LIFI sites (> or =10 years). Riparian inundation at SIFI sites varied from 7 to 45 days during the study period (April 2001-July 2004). SIFI vs. LIFI sites had higher soil moisture but greater groundwater table elevation fluctuation in response to flooding and drought. Rates of net N mineralization were consistently higher at LIFI vs. SIFI sites, and soil inorganic N concentrations were greatest at sites with elevated leaf-litter production. Sites with stable depth to ground water (approximately 1.5 m) supported the greatest leaf-litter production. Reduced leaf production at P. deltoides SIFI sites was attributed to drought-induced recession of ground water and prolonged inundation. We recommend that natural resource managers and restoration practitioners (1) utilize naturalized flows that help maintain riparian groundwater elevations between 1 and 3 m in reaches with mature P. deltoides or where P. deltoides revegetation is desired, (2) identify areas that naturally undergo long periods of inundation and consider restoring these areas to seasonal wetlands, and (3) use native xeric-adapted riparian plants to revegetate LIFI and SIFI sites where

  17. Speciation of inorganic selenium in environmental samples after suspended dispersive solid phase microextraction combined with inductively coupled plasma spectrometric determination.

    PubMed

    Nyaba, Luthando; Matong, Joseph M; Dimpe, K Mogolodi; Nomngongo, Philiswa N

    2016-10-01

    A rapid and effective suspended dispersive solid phase microextraction (SDSPME) was developed for the speciation of inorganic selenium using alumina nanoparticles functionalized with Aliquat-336. The target analytes were preconcentrated and determined by inductively coupled plasma optical emission spectrometry. Alumina nanoparticles were characterized using XRD, BET, SEM and EDX while the functionalized nano-Al2O3 was characterized by FTIR. The effect of pH of the solution on speciation Se in water samples was optimized separately. It was observed that when the pH values of sample solution ranged from 2.0 to 7.0, successful separation of inorganic Se species was achieved. The percentage recoveries for Se (IV) and Se (VI) were >90% and 5%, respectively. The two-level fractional factorial design was used to optimize experimental parameters affecting the preconcentration system. Under optimal conditions, the enrichment factor (EF), limit of detection (LOD) and limit of quantification for Se (IV) were found to be 850, 1.4ngL(-1,) and 4.6ngL(-1), respectively. Furthermore, intra-day and inter-day precisions expressed in terms of relative standard deviation (RSD) were found to be 1.9% and 3.3%, respectively. The effect of coexisting ions on the recovery of Se (IV) was investigated. The accuracy of the developed method was checked by analysis of standard reference material (NIST SRM 1643e). The optimized method was applied for the determination of targets in surface water samples.

  18. Flow injection with in-line reduction column and conductometric detection for determination of total inorganic nitrogen in soil.

    PubMed

    Yanu, Pattama; Jakmunee, Jaroon

    2015-11-01

    A cost effective flow injection (FI) conductometric system has been developed for determination of total inorganic nitrogen (TIN). The system is aimed for evaluation of nitrogen nutrient in soil for agricultural application. Inorganic nitrogen compounds were extracted from soil according to the standard method by using potassium chloride solution as an extractant, and the extracted solution was then injected into the FI system. Nitrate and nitrite are converted to ammonium ion by an in-line reduction column packed with a Devarda's alloy. A gas diffusion unit was incorporated into the FI system to separate ammonium ion from other ions in a donor stream by forming ammonia gas that can diffuse through a PTFE membrane to re-dissolve in an acceptor stream. Conductance of the acceptor stream was directly proportional to ammonium ion concentration. Various parameters affecting reduction efficiency of the column, e.g., column diameter, column packing procedure, and column length was investigated and optimized. A linear calibration graph in the range of 2.00-60.00 mg L(-1) N-NH4(+) (y=0.123x+0.039, R(2) =0.997) was obtained with a limit of detection of 0.47 mg L(-1). Sample throughput of 20 samples h(-1) was achieved. The result of developed method was correlated with total Kjeldahl nitrogen (TKN) obtained from the Kjeldahl digestion method. The proposed method could be used as an alternative method to the Kjeldahl method for determination of TIN in soil.

  19. Laser-induced breakdown spectroscopy (LIBS) technique for the determination of the chemical composition of complex inorganic materials

    NASA Astrophysics Data System (ADS)

    Łazarek, Łukasz; Antończak, Arkadiusz J.; Wójcik, Michał R.; Kozioł, Paweł E.; Stepak, Bogusz; Abramski, Krzysztof M.

    2014-08-01

    Laser-induced breakdown spectroscopy (LIBS) is a fast, fully optical method, that needs little or no sample preparation. In this technique qualitative and quantitative analysis is based on comparison. The determination of composition is generally based on the construction of a calibration curve namely the LIBS signal versus the concentration of the analyte. Typically, to calibrate the system, certified reference materials with known elemental composition are used. Nevertheless, such samples due to differences in the overall composition with respect to the used complex inorganic materials can influence significantly on the accuracy. There are also some intermediate factors which can cause imprecision in measurements, such as optical absorption, surface structure, thermal conductivity etc. This paper presents the calibration procedure performed with especially prepared pellets from the tested materials, which composition was previously defined. We also proposed methods of post-processing which allowed for mitigation of the matrix effects and for a reliable and accurate analysis. This technique was implemented for determination of trace elements in industrial copper concentrates standardized by conventional atomic absorption spectroscopy with a flame atomizer. A series of copper flotation concentrate samples was analyzed for contents of three elements, that is silver, cobalt and vanadium. It has been shown that the described technique can be used to qualitative and quantitative analyses of complex inorganic materials, such as copper flotation concentrates.

  20. Localized surface plasmon resonance mercury detection system and methods

    DOEpatents

    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.

  1. Capillary electrophoresis/mass spectrometry determination of inorganic ions using an ion spray-sheath flow interface.

    PubMed

    Huggins, T G; Henion, J D

    1993-01-01

    The determination of inorganic cations and anions by capillary electrophoresis/mass spectrometry (CE/MS) is reported using an ion spray-sheath flow interface coupling. A twelve-component synthetic mixture of cations which included the positive ions of K, Ba, Ca, Mn, Cd, Co, Pb, Cr, Ni, Zn, Ag, and Cu was loaded into the capillary column at levels ranging from 30 to 300 pg, separated by CE, and detected by indirect UV and in the full-scan (m/z 35-450) positive ion CE/MS mode using an aqueous buffer containing 30 mM creatinine and 8 mM alpha-hydroxyisobutyric acid, pH 4.8. Creatinine forms adducts with the cations which are observed in the gas phase and requires rather high (120 electron volts) declustering energy to dissociate. This produces a reduction in charge state to form the free, singly charged, inorganic cations which are observed in the mass spectra. CE/MS analysis of an aqueous acidic extract of used aircraft engine oil revealed high levels of lead as well as lower levels of chromium and nickel. CE-indirect UV analysis of a synthetic mixture containing 300 pg each of 11 inorganic ions, which included the anions of Br, Cl, NO2, NO3, S2O3, N3, SCN, SO4, SeO4, oxalate, and MoO4, is shown. The running buffer which affected this separation contained 5 mM ammonium dichromate, 10 mM ammonium acetate, and 20 mM diethylenetriamine at pH 9.3. Although indirect UV detection revealed good separation of these anions, CE/MS analysis of this mixture was complicated by interfering ion current signals from the cluster ions formed by the interaction between the additives and the analytes.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Mercury in the ecosystem

    SciTech Connect

    Mitra, S.

    1986-01-01

    This treatise on the environmental dispersion of mercury emphasizes the importance of ''mercury-consciousness'' in the present-day world, where rapidly expanding metallurgical, chemical, and other industrial developments are causing widespread contamination of the atmosphere, soil, and water by this metal and its toxic organic derivatives. Concepts concerning the mechanism of mercury dispersion and methyl-mercury formation in the physico-biological ecosystem are discussed in detail and a substantial body of data on the degree and nature of the mercury contamination of various plants, fish, and land animals by industrial and urban effluents is presented. Various analytical methods for the estimation of mercury in inorganic and organic samples are presented. These serve as a ready guide to the selection of the correct method for analyzing environmental samples. This book is reference work in mercury-related studies. It is written to influence industrial policies of governments in their formulation of control measures to avoid the recurrence of human tragedies such as the well-known Minamata case in Japan, and the lesser known cases in Iraq, Pakistan, and Guatamala.

  3. Square-wave anodic stripping voltammetric determination of thallium(I) at a Nafion/mercury film modified electrode.

    PubMed

    Lu, T H; Yang, H Y; Sun, I W

    1999-06-01

    A Nafion/mercury film electrode (NMFE) was used for the determination of trace thallium(I) in aqueous solutions. Thallium(I) was preconcentrated onto the NMFE from the sample solution containing 0.01 M ethylenediaminetetraacetate (EDTA), and determined by square-wave anodic stripping voltammetry (SWASV). Various factors influencing the determination of thallium(I) were thoroughly investigated. This modified electrode exhibits good resistance to interferences from surface-active compounds. The presence of EDTA effectively eliminated the interferences from metal ions, such as lead(II) and cadmium(II), which are generally considered as the major interferents in the determination of thallium at a mercury electrode. With 2-min preconcentration, linear calibration graphs were obtained over the range 0.05-100 ppb of thallium(I). An even lower detection limit, 0.01 ppb, were achieved with 5-min accumulation. The electrode is easy to prepare and can be readily renewed after each stripping experiment. Applicability of this procedure to various water samples is illustrated.

  4. Anatomical mercury speciation in bay scallops by thio-bearing chelating resin concentration and GC-electron capture detector determination.

    PubMed

    Zhang, Qihua; Yang, Guipeng

    2014-01-01

    The highly toxic methyl-, ethyl- and phenylmercury species that may exist in the three main anatomical parts - the adductor muscle, the mantle and the visceral mass - of bay scallops (Argopecten irradias) were quantitatively released by cupric chloride, zinc acetate, sodium chloride and hydrochloric acid (HCl) under ultrasonic extraction. After centrifugation, the mercury species in the supernatant were concentrated by thio (SH)-bearing chelating resins, eluted with HClO4 and HCl and extracted with toluene. Separation was achieved by capillary GC equipped with programmed temperatures, a constant nitrogen flow and detected by a micro-electron capture detector (μECD). Under optimised conditions, the LODs for methyl-, ethyl- and phenylmercury in bay scallop samples were 1.1, 0.65 and 0.80 ng g(-1), respectively. The maximum RSD for three replicate determinations of methyl-, ethyl- and phenylmercury in bay scallop samples were 13.7%, 14.0% and 11.2%, respectively. In the concentration range of 4-200 ng g(-1) in bay scallop samples, the calibration graphs were linear with correlation coefficients not less than 0.997. Recoveries for spiked samples were in the range of 92.7-103.5% (methylmercury), 87.5-108.3% (ethylmercury) and 91.6-106.0% (phenylmercury), respectively. The method was verified by the determination of methylmercury in a CRM GBW10029 (Total Mercury and Methyl Mercury in Fish Tissue), with results in good agreement with the certified values. Methylmercury - the only existing species in bay scallops - was successfully determined by the method.

  5. Direct determination of inorganic phosphorus in serum with a single reagent.

    PubMed

    Muñoz, M A; Balón, M; Fernandez, C

    1983-02-01

    Estimation of inorganic phosphate in serum based on the formation of "molybdenum blue" may be simplified by eliminating the reduction stage. The yellow complex formed by the reaction of phosphate with molybdate in an acid medium is measured at 390 nm. The yellow complex behaves in accordance with Beer's law over a wide concentration range (to at least 80 mg of P per liter in the initial sample); its molar absorptivity at 390 nm is 2.51 X 10(3) L mol-1 cm-1. Sensitivity is increased in the presence of a detergent (triethanolamine lauryl sulfate), which is also used to dissolve the proteins. Because only one reagent is used (a stable combination of, per liter, 20 mmol of sodium molybdate, 82 mmol of nitric acid, and 100 mg of the detergent), the method is simple and rapid. We describe a manual procedure and an automated one. Within-run precision was 1.9%, and day-to-day precision less than 7%. Results by the automated method compare favorably (r = 0.96) with those obtained by Drewes's method (Clin Chim Acta 39: 81-88, 1972).

  6. ICP OES and CV AAS in determination of mercury in an unusual fatal case of long-term exposure to elemental mercury in a teenager.

    PubMed

    Lech, Teresa

    2014-04-01

    In this work, a case of deliberate self-poisoning is presented. A 14-year-old girl suddenly died during one of the several hospitalizations. Abdominal computer tomography showed a large number of metallic particles in the large intestine. Analysis of blood and internal organs for mercury and other toxic metals carried out by inductively coupled plasma optical emission spectrometry (ICP OES) revealed high concentrations of mercury in kidneys and liver (64,200 and 2470ng/g, respectively), less in stomach (90ng/g), and none in blood. Using cold vapor-atomic absorption spectrometry (CV AAS), high levels of mercury were confirmed in all examined materials, including blood (87ng/g), and additionally in hair. The results of analysis obtained by two techniques revealed that the exposure to mercury was considerable (some time later, it was stated that the mercury originated from thermometers that had been broken over the course of about 1 year, because of Münchausen syndrome). CV AAS is a more sensitive technique, particularly for blood samples (negative results using ICP OES), and tissue samples - with LOQ: 0.63ng/g of Hg (CV AAS) vis-à-vis 70ng/g of Hg (ICP OES). However, ICP OES may be used as a screening technique for autopsy material in acute poisoning by a heavy metal, even one as volatile as mercury.

  7. Selective determination of methyl mercury in biological samples by means of programmed temperature gas chromatography.

    PubMed

    Lorenzo, R A; Carro, A; Rubí, E; Casais, C; Cela, R

    1993-01-01

    A programmed temperature gas chromatographic method is presented by which it is possible to carry out routine analysis of methyl mercury in biological samples prepared according to the AOAC official first action recommendations without the need for preliminary treatment of the columns. This method greatly extends the life of the columns as well as the useful time for analysis; it has good linearity and repeatability. With the proposed method a total of 36 samples can be analyzed daily.

  8. Hair mercury levels in pregnant women in Mahshahr, Iran: fish consumption as a determinant of exposure.

    PubMed

    Salehi, Zohreh; Esmaili-Sari, Abbas

    2010-09-15

    MeHg is a well-documented neurotoxicant even at low levels of exposure. Developing brain, in particular, is vulnerable to that. Through bioaccumulating to differing degrees in various fish species, it can have serious adverse effects on the development and functioning of the human central nervous system, especially during prenatal exposure. Therefore, the purpose of this study was to investigate mercury concentration in hair samples of pregnant women living in Mahshahr located in Khuzestan province, Iran. It assessed the association between fish consumption and specific characteristics that can influence exposure. From April to June 2008, 149 pregnant women were invited to participate in this study. An interview administered questionnaire was used to collect information about age, body weight, height, fish (fresh, canned and shrimp) consumption, pregnancy stage, residence duration, education level, family income and number of dental amalgam fillings. The obtained results showed that the geometric mean and range for hair total Hg concentration was 3.52 microg/g (0.44-53.56 microg/g). About 5.4% of mothers had hair total Hg levels in excess of 10 microg/g. Maternal hair mercury level was less than threshold level of WHO (5 microg/g). As expected, there was a clear increase in hair Hg with reported fresh marine fish consumption (p=0.04). The highest mean for hair mercury level in a group who consumed fish several times per week, was 4.93 microg/g. Moreover, a significant effect of age and residential time on Hg concentration in the hair of the women was found. Pregnant women in Mahshahr consumed large amounts of fish; consequently, most of their offspring were prenatally exposed to moderately high levels of mercury. The results found suggest that pregnant women should decrease their fish consumption.

  9. Determinants of atmospheric mercury concentrations in Reno, Nevada, U.S.A.

    PubMed

    Lyman, Seth N; Gustin, Mae Sexauer

    2009-12-20

    Concentrations of gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM) and particulate-bound mercury (PBM) were measured along with ancillary variables 9 km east of downtown Reno, Nevada, U.S.A. from November 2006 through March 2009. Mean two-year (February 2007 through January 2009) GEM, GOM, and PBM concentrations were 2.0+/-0.7 ng m(-3) (+/-standard deviation), 18+/-22 pg m(-3), and 7+/-7 pg m(-3), respectively. Data collected were compared with observations made at another location just north of the city at 169 m higher elevation. At both locations higher concentrations of GEM and PBM occurred in periods with little atmospheric mixing, indicating that local sources were important for enhancing GEM and PBM concentrations in Reno above that considered continental background. Concentrations of GOM were higher (maximum of 177 pg m(-3)) during periods with higher temperature and lower dew point. Higher GOM concentrations at the higher elevation site with less urban impact relative to the valley site, along with other data trends, support the hypothesis that in northern Nevada subsiding dry air from the free troposphere is a source of GOM to the surface.

  10. [Determination of 11 kinds of inorganic elements in Cortex Spondiacis by microwave digestion/ICP-MS method].

    PubMed

    Luo, Wen; Ma, Jin-Jing; Zhang, Long-Wang; Chen, Cong; Ye, Yan-Qing

    2012-09-01

    The present research aimed to establish a kind of simple and rapid method to detect metal elements in Cortex Spondiacis were determined by microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS). The sample was digested with HNO3-H2O2 acids system. The operation would be simplified and the blank value would be decreased with the above acids systems. Instead of using concent rated acid, this experiment not only can leave out the process of drying or dilution and save time, and extend the life of the instrument, but also eliminates the errors of the inconsistency between digestion solutions and standard solutions. The experimental results showed that Cortex Spondiacis is rich in beneficial elements such as potassium, calcium, magnesium, iron, sodium, and nickel. And the content of harmful elements of the drug, such as mercury, lead, cadmi um and arsenic, is under the national rule, which have some medicinal value. Under the optimum working conditions of the instrument, the detection limits were all smaller than 0.052 1 microg x L(-1), the recovery ratios by standard addition were in the range of 90.8%-113.8% and the RSD was smaller than 5.10% for all elements. Precision and accuracy of determining results are satisfactory. This results are reliable. These results are reliable. The method can meet the need for simultaneity determination of high content element and trace element in Cortex Spondiacis.

  11. The Empire Knight: Patterns of mercury contamination in sediment and biota at a marine site

    SciTech Connect

    Hoff, R.Z.

    1995-12-31

    The Empire Knight, a merchant ship carrying approximately 7.3 metric tons of elemental mercury in its cargo, sank in a storm off the Maine coast in 1 944. Unique attributes of the site include the deep water marine conditions (80 m) and mercury originally in elemental form. Recent evaluations of the site were undertaken to determine environmental risk of the remaining mercury and possible remedial actions. Data collected in 1993 for this risk evaluation included sediment core samples, and a variety of biota samples. Biota were analyzed for total and methylmercury, and the following patterns examined: percent methylmercury, variability between species groups, and spatial patterns related to sediment contamination. Sediment contamination was largely confined to the immediate area near the wreck, with levels decreasing to background within 60 m. Invertebrates within this area had elevated levels of mercury in tissue. Most contamination was in an inorganic form, with percentages of methyl to total mercury below 20%, except for crab and lobster. Most of the residual mercury appears to be largely unavailable to biota, with local invertebrates comprising the main biological receptors. Evidence of bioaccumulation of mercury in higher trophic level organisms was not found, thus mercury did not appear to be a source of contamination beyond the immediate area the wreck.

  12. Effect of pH, sulphate concentration and total organic carbon on mercury accumulation in sediments in the Volta Lake at Yeji, Ghana.

    PubMed

    Kwaansa-Ansah, E E; Voegborlo, R B; Adimado, A A; Ephraim, J H; Nriagu, J O

    2012-03-01

    In this study, pH, total organic carbon, sulphate concentration and mercury concentrations of sediment samples from the Volta Lake at Yeji in the northern part of Ghana were determined. The results indicate that pH ranged from 6.32 to 8.21, total organic carbon ranged from 0.17 to 3.02 g/kg and sulphate concentration from 10.00 to 57.51 mg/kg. Total mercury concentrations ranged from 32.61 to 700 ng/g which is below the International Atomic Energy Agency recommended value of 810 ng/g. Humic substance-bound mercury ranged from 81.15 to 481.31 mg/kg in sediments and its two fractions existed as humic acid-bound mercury > fulvic acid-bound mercury with the ratio of humic substance-bound mercury to fulvic acid-bound mercury as 1.62 on the average. Humic substance-bound mercury and the two fractions fulvic acid-bound mercury and humic substance-bound mercury in sediments were favorably determined and found to correlate significantly positive with total organic carbon (r = 0.538) and total mercury (r = 0.574). However, there were poor correlations between SO(4) (2-) concentrations and humic substance-bound mercury (r = -0.391) as well as the two fractions; fulvic acid (r = -0.406) and humic acid (r = -0.381). By assuming that methyl mercury is mostly formed in sediments, these significant relations suggest that the efficiency of mercury being methylated from a given inorganic form depends on the amount, and most likely biochemical composition of total organic carbon in the lake sediment but not the SO(4) (2-) concentration.

  13. Mercury Exposure and Children’s Health

    PubMed Central

    Bose-O’Reilly, Stephan; McCarty, Kathleen M.; Steckling, Nadine; Lettmeier, Beate

    2011-01-01

    Acute or chronic mercury exposure can cause adverse effects during any period of development. Mercury is a highly toxic element; there is no known safe level of exposure. Ideally, neither children nor adults should have any mercury in their bodies because it provides no physiological benefit. Prenatal and postnatal mercury exposures occur frequently in many different ways. Pediatricians, nurses, and other health care providers should understand the scope of mercury exposures and health problems among children and be prepared to handle mercury exposures in medical practice. Prevention is the key to reducing mercury poisoning. Mercury exists in different chemical forms: elemental (or metallic), inorganic, and organic (methylmercury and ethyl mercury). Mercury exposure can cause acute and chronic intoxication at low levels of exposure. Mercury is neuro-, nephro-, and immunotoxic. The development of the child in utero and early in life is at particular risk. Mercury is ubiquitous and persistent. Mercury is a global pollutant, bio-accumulating, mainly through the aquatic food chain, resulting in a serious health hazard for children. This article provides an extensive review of mercury exposure and children’s health. PMID:20816346

  14. Method development for the control determination of mercury in seafood by solid-sampling thermal decomposition amalgamation atomic absorption spectrometry (TDA AAS).

    PubMed

    Torres, D P; Martins-Teixeira, M B; Silva, E F; Queiroz, H M

    2012-01-01

    A very simple and rapid method for the determination of total mercury in fish samples using the Direct Mercury Analyser DMA-80 was developed. In this system, a previously weighted portion of fresh fish is combusted and the released mercury is selectively trapped in a gold amalgamator. Upon heating, mercury is desorbed from the amalgamator, an atomic absorption measurement is performed and the mercury concentration is calculated. Some experimental parameters have been studied and optimised. In this study the sample mass was about 100.0 mg. The relative standard deviation was lower than 8.0% for all measurements of solid samples. Two calibration curves against aqueous standard solutions were prepared through the low linear range from 2.5 to 20.0 ng of Hg, and the high linear range from 25.0 to 200.0 ng of Hg, for which a correlation coefficient better than 0.997 was achieved, as well as a normal distribution of the residuals. Mercury reference solutions were prepared in 5.0% v/v nitric acid medium. Lyophilised fish tissues were also analysed; however, the additional procedure had no advantage over the direct analysis of the fresh fish, and additionally increased the total analytical process time. A fish tissue reference material, IAEA-407, was analysed and the mercury concentration was in agreement with the certified value, according to the t-test at a 95% confidence level. The limit of quantification (LOQ), based on a mercury-free sample, was 3.0 µg kg(-1). This LOQ is in accordance with performance criteria required by the Commission Regulation No. 333/2007. Simplicity and high efficiency, without the need for any sample preparation procedure, are some of the qualities of the proposed method.

  15. Effects of mercury (II) species on cell suspension cultures of catharanthus roseus

    SciTech Connect

    Zhu, L. ); Cullen, W.R. )

    1994-11-01

    Mercury has received considerable attention because of its high toxicity. Widespread contamination with mercury poses severe environmental problems despite our extensive knowledge of its toxicity in living systems. It is generally accepted that the toxicity of mercury is related to its oxidation states and species, the organic forms being more toxic than the inorganic forms. In the aquatic environment, the toxicity of mercury depends on the aqueous speciation of the mercuric ion (Hg[sup 2+]). Because of the complex coordination chemistry of mercury in aqueous systems, the nature of the Hg[sup 2+] species present in aquatic environments is influenced greatly by water chemistry (e. g, pH, inorganic ion composition, and dissolved organics). Consequently, the influence of environmental factors on the aqueous speciation of mercury has been the focus of much attention. However, there is very little information available regarding the effects of the species and speciation on Hg (II) toxicity in plant-tissue cultures. Catharanthus roseus (C. roseus), commonly called the Madagascar Periwinkle, is a member of the alkaloid rich family Apocynaceae. The present investigation was concerned with the toxicity of mercury on the growth of C. roseus cell suspension cultures as influenced by mercury (II) species and speciation. The specific objectives of the study were to (a) study the effects of mercury species on the growth of C. roseus cultures from the point of view of environmental biology and toxicology; (b) evaluate the effects of selenate, selenite and selected ligands such as chloride, 1-cysteine in the media on the acute toxicity of mercuric oxide; (c) determine the impact of the initial pH of the culture media on the toxicities of mercuric compounds; (d) discuss the dependence of the toxicity on the chemical species and speciation of Hg (II). 11 refs., 7 figs., 2 tabs.

  16. Capillary electrochromatography with contactless conductivity detection for the determination of some inorganic and organic cations using monolithic octadecylsilica columns.

    PubMed

    Mai, Thanh Duc; Pham, Hung Viet; Hauser, Peter C

    2009-10-27

    A fast separation of alkali and alkaline earth metal cations and ammonium was carried out by capillary electrochromatography on monolithic octadecylsilica columns of 15 cm length and 100 microm inner diameter using water/methanol mixtures containing acetic acid as mobile phase. On-column contactless conductivity detection was used for quantification of these non-UV-absorbing species. The method was also extended successfully to the determination of small amines as well as of amino acids, and the separation selectivity was optimized by varying the composition of the mobile phase. Detection limits of about 1 microM were possible for the inorganic cations as well as for the small amines, while the amino acids could be quantified down to about 10 microM. The separation of 12 amino acids was achieved in the relatively short time of 10 min.

  17. HABITAT-SPECIFIC FORAGING AND SEX DETERMINE MERCURY CONCENTRATIONS IN SYMPATRIC BENTHIC AND LIMNETIC ECOTYPES OF THE THREESPINE STICKLEBACK

    PubMed Central

    Willacker, James J.; Von Hippel, Frank A.; Ackerly, Kerri L.; O’Hara, Todd M.

    2013-01-01

    Mercury (Hg) is a widespread environmental contaminant known for the neurotoxicity of its methylated forms, especially monomethylmercury, which bioaccumulates and biomagnifies in aquatic food webs. Mercury bioaccumulation and biomagnification rates are known to vary among species utilizing different food webs (benthic vs limnetic) within and between systems. The authors assessed whether carbon and nitrogen stable isotope values and total Hg (THg) concentrations differed between sympatric benthic and limnetic ecotypes and sexes of threespine stickleback fish (Gasterosteus aculeatus) from Benka Lake, Alaska, USA. The mean THg concentration in the limnetic ecotype was significantly higher (26 mg/kg dry wt, 16.1%) than that of the benthic ecotype. Trophic position and benthic carbon percentage utilized were both important determinants of THg concentration; however, the 2 variables were of approximately equal importance in females, whereas trophic position clearly explained more of the variance than benthic carbon percentage in males. Additionally, strong sex effects (45 mg/kg dry wt, 29.4%) were observed in both ecotypes, with female fish having lower THg concentrations than males. These results indicate that trophic ecology and sex are both important determinants of Hg contamination even within a single species and lake and likely play a role in governing Hg concentrations in higher trophic levels. PMID:23456641

  18. Preparation of a gold electrode modified with tri-n-octylphosphine oxide and its application to determination of mercury in the environment.

    PubMed

    Lexa, J; Stulík, K

    1989-08-01

    A gold film electrode modified with a film of tri-n-octylphosphine oxide (TOPO) in a PVC matrix has been prepared and tested. Cyclic voltammetric experiments have shown that the electrode is useful for highly selective voltammetric determinations of a number of metals, primarily Hg, Cr, Fe, Bi, Sb, U and Pb. The electrode has been applied to the anodic stripping voltammetric determination of mercury in some environmental samples, such as river sediments. Concentrations of 0.02-50 ppm of mercury can be determined with good precision and accuracy, as demonstrated by analyses of reference materials. A selective decomposition of the samples at laboratory temperature decreases the danger of sample contamination and of volatilization of mercury.

  19. Mercury Methylation and Environmental Effects of Inactive Mercury Mines in the Circum-Pacific Region

    NASA Astrophysics Data System (ADS)

    Gray, J. E.

    2001-05-01

    Mercury mines worldwide contain of some the highest concentrations of mercury on earth, and as a result of local mercury contamination, these mines represent areas of environmental concern when mine-drainage enters downstream aquatic systems. The most problematic aspect of mine site mercury contamination is the conversion of inorganic mercury to highly toxic organic mercury compounds, such as methylmercury, and their subsequent uptake by aquatic organisms in surrounding ecosystems. Mercury and methylmercury concentrations were measured in sediment and water samples collected from several inactive mercury mines in Nevada, Alaska, and the Philippines, which are part of the circum-Pacific mineral belt. The mines studied represent different mercury deposit types and sizes, and climatic settings. Geochemical data collected from these mines indicate that areas surrounding hot-springs type mercury deposits generally have lower methylmercury concentrations than silica-carbonate mercury deposits. In hot-springs mercury deposits in Nevada and Alaska, ore is dominantly cinnabar with few acid-water generating minerals such as pyrite, and as a result, mine-water drainage has near neutral pH in which there is low solubility of mercury. Conversely, silica-carbonate deposits, such as Palawan, Philippines, contain abundant cinnabar and pyrite, and the resultant acidic-mine drainage generally has higher concentrations of mercury and methylmercury. Additional factors such as the proximity of mercury mines to wetlands, climatic effects, or mine wastes containing highly soluble mercury compounds potentially enhance mercury methylation. The Palawan mercury mine may be a unique example where several adverse environmental factors produced local mercury contamination, high mercury methylation, fish contamination, and mercury poisoning of humans that consumed these contaminated fish.

  20. Synergic effect of gold mining and damming on mercury contamination in fish.

    PubMed

    Boudou, Alain; Maury-Brachet, Régine; Coquery, Marina; Durrieu, Gilles; Cossa, Daniel

    2005-04-15

    Since the late 1980s, several studies have shown that human populations in the Amazon basin are exposed to high mercury levels in their fish diet. Gold mining, which releases the metal during the amalgamation process and erodes soils naturally rich in mercury, is regarded as the main contamination source. Here, we present the results of a comparative study of mercury distribution in the water and fish of two adjacent rivers in French Guiana, with and without gold mining activities. As a consequence of a marked difference in suspended particulate matter between the two systems, total mercury concentrations in unfiltered water samples were higher in the mined river (25.4-34.9 ng L(-1)) as compared to the reference one (2.1-5.4 ng L(-1)). Surprisingly, no significant differences were observed in mercury concentrations between 13 common fish species at upstream sites. In sharp contrast, mercury concentration of fish caught downstream a hydroelectric reservoir, where the two rivers flow, was up to 8-fold higher than that upstream. Mercury speciation measurements allowed one to relate these differences in fish to the water distribution of monomethylmercury, the mercury chemical species that biomagnifies along aquatic foodwebs. Indeed, mean dissolved monomethylmercury concentrations were low and similar in both rivers (0.03-0.06 ng L(-1)), while they were 10 times higher (up to 0.56 ng L(-1)) in the water outflowing the hydroelectric dam. Dissolved monomethylmercury determinations along a water column profile suggest that methylation of inorganic mercury occurs in the deep anoxic part in reservoir. We conclude that mercury mobilization related to gold mining is not solely sufficient to account for high concentrations in fish and that environmental conditions that favor mercury methylation, such as anoxia, are needed.

  1. Mercury and selenium in workers previously exposed to mercury vapour at a chloralkali plant.

    PubMed Central

    Ellingsen, D G; Holland, R I; Thomassen, Y; Landro-Olstad, M; Frech, W; Kjuus, H

    1993-01-01

    The concentrations of total mercury (B-Hg), inorganic mercury (B-IHg), and methyl mercury (B-MeHg) in whole blood, urinary mercury (U-Hg), and selenium in urine (U-Se) and whole blood (B-Se) were determined in 74 chloralkali workers previously exposed to Hg vapour, and compared with 51 age matched referents. Dental amalgam state, fish consumption, and exposure related indices were studied with regard to the determined elements. A significant relation between the surface of dental amalgam and U-Hg (Pearson's r = 0.63, p < 0.001) was found among the referents. Mean U-Se was significantly lower (p < 0.001) among the subjects previously exposed to Hg (34.1 nmol/mmol creatinine) compared with that for the referents (42.6 nmol/mmol creatinine). A significant negative relation between the cumulative Hg dose and U-Se was also found. The mechanisms and the clinical significance of these findings are not clear. No relation between current U-Hg and previous occupational exposure to Hg was found among subjects in whom exposure had ceased more than one year before the study. PMID:8398862

  2. Inorganic species of arsenic in soil solution determined by microcartridges and ferrihydrite-based diffusive gradient in thin films (DGT).

    PubMed

    Moreno-Jiménez, Eduardo; Six, Laetitia; Williams, Paul N; Smolders, Erik

    2013-01-30

    The bioavailability of soil arsenic (As) is determined by its speciation in soil solution, i.e., arsenite [As(III)] or arsenate [As(V)]. Soil bioavailability studies require suitable methods to cope with small volumes of soil solution that can be speciated directly after sampling, and thereby minimise any As speciation change during sample collection. In this study, we tested a self-made microcartridge to separate both As species and compared it to a commercially available cartridge. In addition, the diffusive gradient in thin films technique (DGT), in combination with the microcartridges, was applied to synthetic solutions and to a soil spiked with As. This combination was used to improve the assessment of available inorganic As species with ferrihydrite(FH)-DGT, in order to validate the technique for environmental analysis, mainly in soils. The self-made microcartridge was effective in separating As(III) from As(V) in solution with detection by inductively coupled plasma optical emission spectrometry (ICP-OES) in volumes of only 3 ml. The DGT study also showed that the FH-based binding gels are effective for As(III) and As(V) assessment, in solutions with As and P concentrations and ionic strength commonly found in soils. The FH-DGT was tested on flooded and unflooded As spiked soils and recoveries of As(III) and As(V) were 85-104% of the total dissolved As. This study shows that the DGT with FH-based binding gel is robust for assessing inorganic species of As in soils.

  3. Determination of reference concentrations for inorganic analytes in groundwater at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    1996-03-01

    Background (or reference) concentrations for inorganics in Y-12 Plant groundwater were determined using a combination of statistical cluster analysis and conventional cumulative probability graphing. Objective was to develop a methodology for setting groundwater reference concentrations that uses all site groundwater data instead of only results of sampling upgradient of groundwater contamination. Y-12 was selected as prototype because the groundwater data set is very large and the data have been consistently collected since 1986. A conceptual framework of groundwater quality at Y-12 was formulated; as a quality check, data were statistically modeled or clustered. Ten hydrochemical regimes or clusters were identified. Six well clusters closely corresponded to the water quality framework and to observed water quality regimes in groundwater at Y-12. Four clusters were associated with nitrate, an S-3 Site contaminant, or with nonspecific contaminants commonly encountered at shallow depths at industrial sites (e.g., road salt). These four clusters were eliminated from the reference data set. Cumulative probability graphs were used within a cluster or group of clusters to distinguish contaminated wells from wells with ambient water quality. Only median values of unfiltered samples were plotted. Outlying data points (assumed to be contaminated samples) were identified and eliminated from the data set. When all outliers for a given inorganic had been identified and deleted from the data set, the reference concentration was set at the one-sided upper tolerance limit on the 95th percentile with 95% confidence. The methodology proved useful in integrating a large amount of data into the Y-12 plant groundwater conceptual framework and in identifying those wells or groups of wells that have monitoring or sample and analysis problems or that may be monitoring site-related contamination.

  4. Determination of rock type on Mercury and the moon through remote sensing in the thermal infrared

    NASA Technical Reports Server (NTRS)

    Tyler, Ann L.; Kozlowski, Richard W. H.; Lebofsky, Larry A.

    1988-01-01

    Thermal infrared emission spectra of the moon and Mercury have been obtained using the Si:As photoconductor and circular variable filter at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. Lunar spectra from 7.2 to 12.2 microns for two different locations in the south polar highlands have Christiansen frequency peaks at 8.1 microns and 7.9 microns, respectively. This indicates different compositions at the two locations; mafic in the first case, more felsic in the second. Emission spectra from Mercury are not as spatially localized,; however, the longitude of maximum contribution to the spectrum can be calculated from thermal models of the earth-facing disk. Results for areas centered at two longitudes have been obtained. Two locations in the intercrater plains were observed. At 40-deg longitude (very near the crater Homer), a peak at 7.9 microns indicates mafic igneous rock type. Spectra emanating from 46-deg longitude have peaks at 7.8 microns, indicating a region borderline between mafic and intermediate composition.

  5. Why mercury prefers soft ligands

    SciTech Connect

    Riccardi, Demian M; Guo, Hao-Bo; Gu, Baohua; Parks, Jerry M; Summers, Anne; Miller, S; Liang, Liyuan; Smith, Jeremy C

    2013-01-01

    Mercury (Hg) is a major global pollutant arising from both natural and anthropogenic sources. Defining the factors that determine the relative affinities of different ligands for the mercuric ion, Hg2+, is critical to understanding its speciation, transformation, and bioaccumulation in the environment. Here, we use quantum chemistry to dissect the relative binding free energies for a series of inorganic anion complexes of Hg2+. Comparison of Hg2+ ligand interactions in the gaseous and aqueous phases shows that differences in interactions with a few, local water molecules led to a clear periodic trend within the chalcogenide and halide groups and resulted in the well-known experimentally observed preference of Hg2+ for soft ligands such as thiols. Our approach establishes a basis for understanding Hg speciation in the biosphere.

  6. Organomercurial-volatilizing bacteria in the mercury-polluted sediment of Minamata Bay, Japan

    SciTech Connect

    Nakamura, Kunihiko; Sakamoto, Mineshi; Uchiyama, Hiroo; Yagi, Osami )

    1990-01-01

    A total of 4,604 bacterial strains isolated from the sediments of Minamata Bay and nearby low-level-mercury stations (control stations) were screened for the ability to volatilize mercury from inorganic and organic mercurial compounds. The strains that volatilize mercury from several kinds of organomercurials were found only in the sediments of Minamata Bay.

  7. Determination of Antimony (III) in Real Samples by Anodic Stripping Voltammetry Using a Mercury Film Screen-Printed Electrode.

    PubMed

    Domínguez-Renedo, Olga; Gómez González, M Jesús; Arcos-Martínez, M Julia

    2009-01-01

    This paper describes a procedure for the determination of antimony (III) by differential pulse anodic stripping voltammetry using a mercury film screen-printed electrode as the working electrode. The procedure has been optimized using experimental design methodology. Under these conditions, in terms of Residual Standard Deviation (RSD), the repeatability (3.81 %) and the reproducibility (5.07 %) of the constructed electrodes were both analyzed. The detection limit for Sb (III) was calculated at a value of 1.27×10(-8) M. The linear range obtained was between 0.99 × 10(-8) - 8.26 × 10(-8) M. An analysis of possible effects due to the presence of foreign ions in the solution was performed and the procedure was successfully applied to the determination of antimony levels in pharmaceutical preparations and sea water samples.

  8. Determination of Antimony (III) in Real Samples by Anodic Stripping Voltammetry Using a Mercury Film Screen-Printed Electrode

    PubMed Central

    Domínguez-Renedo, Olga; Gómez González, M. Jesús; Arcos-Martínez, M. Julia

    2009-01-01

    This paper describes a procedure for the determination of antimony (III) by differential pulse anodic stripping voltammetry using a mercury film screen-printed electrode as the working electrode. The procedure has been optimized using experimental design methodology. Under these conditions, in terms of Residual Standard Deviation (RSD), the repeatability (3.81 %) and the reproducibility (5.07 %) of the constructed electrodes were both analyzed. The detection limit for Sb (III) was calculated at a value of 1.27×10−8 M. The linear range obtained was between 0.99 × 10−8 − 8.26 × 10−8 M. An analysis of possible effects due to the presence of foreign ions in the solution was performed and the procedure was successfully applied to the determination of antimony levels in pharmaceutical preparations and sea water samples. PMID:22389596

  9. Open focused microwave-assisted sample preparation for rapid total and mercury species determination in environmental solid samples.

    PubMed

    Tseng, C M; Garraud, H; Amouroux, D; Donard, O F; de Diego, A

    1998-01-01

    This paper describes rapid, simple microwave-assisted leaching/ digestion procedures for total and mercury species determination in sediment samples and biomaterials. An open focused microwave system allowed the sample preparation time to be dramatically reduced to only 24 min when a power of 40-80 W was applied. Quantitative leaching of methylmercury from sediments by HNO(3) solution and complete dissolution of biomaterials by an alkaline solution, such as 25% TMAH solution, were obtained. Methylmercury compounds were kept intact without decomposition or losses by evaporation. Quantitative recoveries of total mercury were achieved with a two-step microwave attack using a combination of HNO(3) and H(2)0(2) solutions as extractant. The whole pretreatment procedure only takes 15 min, which can be further shortened by an automated robust operation with an open focused system. These analytical procedures were validated by the analysis of environmental certified reference materials. The results confirm that the open focused microwave technique is a promising tool for solid sample preparation in analytical and environmental chemistry.

  10. Electromembrane extraction-preconcentration followed by microvolume UV-Vis spectrophotometric determination of mercury in water and fish samples.

    PubMed

    Fashi, Armin; Yaftian, Mohammad Reza; Zamani, Abbasali

    2017-04-15

    Electromembrane extraction technique combined with microvolume UV-Vis spectrophotometric detection was proposed for the preconcentration-determination of mercury in water and fish samples. The optimized conditions for preconcentration step were: the applied potential 70V, bis(2-ethylhexyl) phosphate as the extractant in 1-octanol 2% v/v, extraction time 10min, stirring rate 700rpm, acceptor and donor solutions pH 3 and 7, respectively. The linear range was found to be 2.3-950.0μgL(-1) and 40-9500μgkg(-1) in water and fish samples, with corresponding detection limits of 0.7μgL(-1) and 12μgkg(-1), respectively. The method showed satisfactory repeatability and reproducibility (CV<6%). Methodological validation was performed by using cold vapor atomic absorption spectroscopy. The proposed method provided a rapid, sensitive and accurate method which is applicable for routine analysis of total mercury contents in water and fish samples.

  11. Determination of total mercury in whole-body fish and fish muscle plugs collected from the South Fork of the Humboldt River, Nevada, September 2005

    USGS Publications Warehouse

    May, Thomas W.; Brumbaugh, William G.

    2007-01-01

    This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the U.S. Bureau of Reclamation, to determine mercury concentrations in whole-body fish and fish muscle plugs from the South Fork of the Humboldt River near Elko in the Te-Moak Indian Reservation. A single muscle plug was collected from beneath the dorsal fin area in each of the three whole-body fish samples. After homogenization and lyophilization of the muscle plugs and whole-body fish samples, mercury concentrations were determined with a direct mercury analyzer utilizing the process of thermal combustion-gold amalgamation atomic absorption spectroscopy. Mercury concentrations in whole-body fish ranged from 0.048 to 0.061 microgram per gram wet weight, and 0.061 to 0.082 microgram per gram wet weight in muscle plugs. All sample mercury concentrations were well below the U.S. Environmental Protection Agency's fish consumption advisory of 0.30 microgram per gram wet weight.

  12. Determination of Background Concentrations of Inorganics in Soils and Sediments at Hazardous Waste Sites

    EPA Pesticide Factsheets

    The purpose of this paper is to provide RPMs and others investigating hazardous waste sites a summary of the technical issues that need to be considered when determining if a site (i.e., hazardous waste site/area of concern) has elevated levels of ...

  13. Comparison of intermittent and continuous exposures to inorganic mercury in the mussel, Mytilus edulis: accumulation and sub-lethal physiological effects.

    PubMed

    Amachree, Dokuboba; Moody, A John; Handy, Richard D

    2014-11-01

    Aquatic organisms are often subject to intermittent exposure to pollutants in real ecosystems. This study aimed to compare mercury accumulation and the physiological responses of mussels, Mytilus edulis during continuous and intermittent exposure to the metal. Mussels were treated in a semi-static, triplicated design to either a control (no added Hg) or 50 µg l(-1) Hg as HgCl2 in continuous (daily) or intermittent (2 day exposure, 2 days in clean seawater alternately) exposure for 14 days. A time-dependent increase in Hg accumulation was observed in the continuous exposure, while the intermittent treatment showed step-wise changes in Hg concentrations with the exposure profile, especially in the gills. At the end of the experiment, tissue Hg concentrations were significantly increased in the continuous compared to the intermittent exposure for digestive gland (4 fold), gonad and remaining soft tissue (>2 fold), but not for the gill and adductor muscle. There was no observed oxidative damage at the end of the experiment as measured by the thiobarbituric acid reactive substances (TBARS) concentrations in tissues from all treatments. However, total glutathione was significantly decreased in the gill and digestive gland of both the continuous and intermittent exposure by the end of the experiment. The neutral red retention ability of the haemocytes was not affected, but total haemocyte counts were significantly decreased (<2 fold) in the intermittent compared to the continuous exposure. Histopathological examinations showed less pathology in the gill, but more inflammation in the digestive gland of mussels for the intermittent compared to the continuous exposure. Overall, the results showed that Hg accumulation from intermittent exposure was less than that of the continuous exposure regime, but the sub-lethal responses are sometimes more severe than expected in the former.

  14. [Determination of inorganic elements in the soil-grass-animal system by sealed microwave digestion ICP-AES].

    PubMed

    Xin, Guo-Sheng; Hu, Zheng; Zhou, Wei; Yang, Zhi-Qiang; Guo, Xu-Sheng; Long, Rui-Jun

    2010-02-01

    The contents of inorganic elements including K, Ca, Na, Mg, P, S, Fe, Cu, Mn, Zn, Mo, and Co in the soil-grass-animal mineral system from Qinghai Tibetan Plateau were determined by ICP-AES using high pressure system-sealed microwave digestion. The sample of soil was digested with HNO3-HF-H2O2 acids system, but others including pasture, animal fur, liver, and serum were digested with HNO3-H2O2 acids system. The operation would be simplified and the blank value would be decreased with the above acids systems. The results were proved to be reliable with the relative standard deviation being 0.271%-2.633% for Ca, 2.971%-4.854% for Co, 0.372%-2.874% for Cu, 0.600%-3.683% for Fe, 0.347%-2.829% for K, 0.626%-2.593% for Mg, 0.705%-4.828% for Mn, 2.946%-4.622% for Mo, 0.689%-3.621% for Na, 0.422%-3.890% for P, and 0.143%-4.622% for S, 0.166%-2.399% for Zn, and all of them were less than 5% for all the elements, and the recovery being 97.1%-101.4% for Ca, 93.5%-112.5% for Co, 95.2%-104.0% for Cu, 96.9%-104.2% for Fe, 96.1%-105.6% for K, 96.2%-102.8% for Mg, 91.5%-108.9% for Mn, 95.0%-113.5% for Mo, 95.2%-101.8% for Na, 94.7%-100.7% for P, 98.3%-108.4% for S, and 97.5%-102.0% for Zn by adding standard recovery experiment. The results of determination were proved that the method of sealed microwave digestion ICP-AES was sensitive, precise, easy to operate and rapid for the determination of inorganic elements in the soil-grass-animal mineral system, and could satisfy the sample examination request. The methods and results were meaningful to research on the soil-pasture-animal mineral system including the contents of mineral elements, the circulation of mineral elements, the interaction, and the application of mineral additive.

  15. Determination of inorganic pollutants in soil after volatilization using microwave-induced combustion

    NASA Astrophysics Data System (ADS)

    Picoloto, Rochele S.; Wiltsche, Helmar; Knapp, Günter; Mello, Paola A.; Barin, Juliano S.; Flores, Erico M. M.

    2013-08-01

    Microwave-induced combustion (MIC) was applied for analyte volatilization from soil and subsequent determination of As, Cd and Pb by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES), and Hg by cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS). Soil samples (up to 300 mg) were mixed with microcrystalline cellulose, pressed as pellets and combusted in closed quartz vessels pressurized with 20 bar O2. Analytes were volatilized from soil during combustion and quantitatively absorbed in a suitable solution: nitric acid (1, 2, 4 or 6 mol L- 1) or a solution of nitric (2 mol L- 1) and hydrochloric (1, 2 or 4 mol L- 1) acids. Accuracy was evaluated using certified reference materials of soil (NIST 2709, San Joaquin Soil) and sediment (SUD-1, Sudbury sediment for trace elements). Agreement with certified values was better than 95% (t-test, 95% confidence level) for all analytes when 6 mL of a solution of 2 mol L- 1 HNO3 and 2 mol L- 1 HCl was used with a reflux step of 5 min. The limit of detection was 0.010, 0.002, 0.009 and 0.012 μg g- 1 for As, Cd, Hg and Pb, respectively using ICP-MS determination. A clear advantage of the proposed method over classical approaches is that only diluted solution is used. Moreover, a complete separation of the analytes from matrix is achieved minimizing potential interferences in ICP-MS or ICP-OES determination. Up to eight samples can be digested in a single run of only 25 min, resulting in a solution suitable for the determination of all analytes by both techniques.

  16. Simultaneous determination of inorganic disinfection by-products and the seven standard anions by ion chromatography.

    PubMed

    Schminke, G; Seubert, A

    2000-08-25

    For the first time, an ion chromatographic method for the simultaneous determination of the disinfection by-products bromate, chlorite, chlorate, and the so-called seven standard anions, fluoride, chloride, nitrite, sulfate, bromide, nitrate and orthophosphate is presented. The separation of the ten anions was carried out using a laboratory-made high-capacity anion-exchanger. The high capacity anion-exchanger allowed the direct injection of large sample volumes without any sample pretreatment, even in the case of hard water samples. For quantification of fluoride, chloride, nitrite, sulfate, bromide, nitrate, orthophosphate and chlorate, a conductivity detection method was applied after chemical suppression. The post-column reaction, based on chlorpromazine, was optimized for the determination of chlorite and bromate. The method detection limit for bromate measured in deionized water is 100 ng/l and for chlorite, it is 700 ng/l. In hard drinking water, the method's detection limits are 700 ng/l (bromate) and 3.5 microg/l (chlorite). The method's detection limits for the other eight anions, determined by conductivity detection, are between 100 microg/l (nitrite) and 1.6 mg/l (chlorate).

  17. Copper, lead, mercury and zinc in periphyton from the south Florida ecosystem

    USGS Publications Warehouse

    Cox, T.; Simon, N.S.; Newland, L.

    1999-01-01

    Periphyton samples from the Big Cypress National Preserve were analyzed for concentrations of copper, lead, zinc, mercury, and methylmercury. Concentrations of organic carbon, inorganic carbon, nitrogen, and phosphorus in periphyton samples also were determined. The samples were extracted with sodium acetate solution at a pH of 5.5 to determine exchangeable and carbonate phase metal concentrations in periphyton. Total metal concentrations in the periphyton were directly related to the degree of calcite saturation in the water column. Exchangeable and carbonate phase metal concentrations were directly related to the percent inorganic carbon in the samples. A connection between the geochemistry of trace metals and calcite precipitation and dissolution is suggested.

  18. A review of Model Production Function age determinations on the Mercury surface

    NASA Astrophysics Data System (ADS)

    Massironi, Matteo; Cremonese, Gabriele; Marchi, Simone; Martellato, Elena; Giacomini, Lorenza; Ferrari, Sabrina

    The Model Production Function (MPF) chronology relies on the estimate of the crater size-frequency distribution for a specific planet on the basis of theoretical prediction of the impactor flux (Marchi et al., 2009). Hence it is a readily and flexible method to infer ages on any planets also considering a variable impact flux through time. In addition the methodology derive crater size distribution function from the distribution of impactors applying only once the Holsapple and Housen (2007) scaling law; this allows a consistent control of the function itself and an improved fit of the crater statistics, which, on its own, may give even some insights for the uppermost layering and rheology of the investigated crusts (Massironi et al. 2009). During the here proposed presentation, we will discuss all the applications of MPF method realized on the hermean surface so far. This will give us the opportunity to explain the importance of the geological interpretation required to correctly apply this methodology as well as to illustrate strength and weakness of such an approach. References Holsapple, K. A., and Housen K. R. (2007). A crater and its ejecta: An interpreta-tion of Deep Impact, ICARUS, 187, 345 -356. Marchi S, Mottola S, Cremonese G, Massironi M., Martellato E (2009). A New Chronology for the Moon and Mercury. THE ASTRONOM-ICAL JOURNAL, vol. 137; p. 4936-4948. Massironi M., Cremonese G, Marchi S, Martellato E, Mottola S, Wagner RJ (2009). Mercury's geochronology revised by applying Model Pro-duction Function to Mariner 10 data: Geological implications. GEOPHYSICAL RESEARCH LETTERS, vol. 36; L21204.

  19. The role of Nrf2/Keap1 signaling in inorganic mercury induced oxidative stress in the liver of large yellow croaker Pseudosciaena crocea.

    PubMed

    Zeng, Lin; Zheng, Jia-Lang; Wang, Yong-Hong; Xu, Mei-Ying; Zhu, Ai-Yi; Wu, Chang-Wen

    2016-10-01

    The aim of the present study was to evaluate the effects of acute inorganic Hg exposure (0, 32 and 64μgHgL(-1)) on lipid peroxidation, activities and gene expression of antioxidant enzymes (Cu/Zn-SOD, CAT, GPx, GR and GST), and mRNA levels of the Keap1-Nrf2 signaling molecules at different exposure times (6h, 12h, 24h, 48h, and 96h) in the liver of large yellow croaker Pseudosciaena crocea. The results showed that lipid peroxidation was sharply reduced by 32μg Hg L(-1) during 6-12h before returning to control levels. Similarly, lipid peroxidation was significantly reduced during 6-12h followed by a sharp increase towards the end of the exposure in the 64μgHgL(-1) group. There was a negative relationship between lipid peroxidation and antioxidant enzyme activities, and positive relationship between activities and gene expression of antioxidant enzymes, suggesting that the changes at a molecular level may underlie enzymatic level and accordingly affect hepatic lipid peroxidation. Obtained results also showed a coordinated transcriptional regulation of antioxidant genes, suggesting that Nrf2 is required for the protracted induction of these genes. Furthermore, a negative relationship between the mRNA levels of Nrf2 and Keap1 indicated that Keap1 may play an important role in switching off the Nrf2 response. In conclusion, this is the first study to elucidate effects of waterborne Hg on antioxidant system in large yellow croaker through the Keap1-Nrf2 pathway, which will aid our understanding of the molecular mechanisms of waterborne heavy metal on antioxidant responses in fish.

  20. Determination of low-molecular-mass aliphatic carboxylic acids and inorganic anions from kraft black liquors by ion chromatography.

    PubMed

    Käkölä, Jaana M; Alén, Raimo J; Isoaho, Jukka Pekka; Matilainen, Rose B

    2008-05-09

    An ion chromatographic (IC) method with suppressed conductivity detection (CD) was developed and validated for the quantitative determination of several low-molecular-mass aliphatic mono- and dicarboxylic acids as their carboxylate anions together with some inorganic anions (chloride, sulfate, and thiosulfate) from kraft black liquors. To confirm the identification of some carboxylate anions which lack commercial model substances, a qualitative IC method with suppressed electrospray ionization mass spectrometry (ESI-MS) was also developed. The separations were performed on an IonPac AS 11-HC anion-exchange column operated at 25 degrees C within 25 min by a gradient elution with aqueous potassium hydroxide (suppressed CD in the AutoRegen mode) or sodium hydroxide (suppressed ESI-MS in the pressurized bottle mode). In the validation process a mixture of carboxylic acids and inorganic anions in aqueous media and in seven different types of wood and non-wood black liquor samples were quantitatively analyzed by IC-CD. As a result, calibration lines with correlation coefficients of 1.00 for all analytes were achieved at a concentration range from 0.05 to 105 mg L(-1). In black liquor samples intra-day (n=6) precision values ranged from 0.9 to 5%. Day-to-day (n1=3) and intermediate precision values were less than 5% for all other compounds except sulfate and thiosulfate. The variability in the thiosulfate and sulfate results is due in large part to the oxidation of sulfide and thiosulfate, respectively. Recoveries were close to 100% with standard deviations less than 8%. Depending of the analyte, the limits of detection and quantification were, respectively, between 1 and 8 microg L(-1) and between 3 and 27 microg L(-1) for standard compounds in aqueous media and between 6 and 106 microg L(-1) and between 14 and 148 microg L(-1) for black liquor samples. These validation results clearly indicated that with respect to selectivity, linearity, limits of detection and

  1. Near-infrared spectroscopy study for determination of adsorbed acetochlor in the organic and inorganic bentonites.

    PubMed

    Tomić, Zorica P; Ašanin, Darko; Đurović, Rada; Đorđević, Aleksandar; Makreski, Petre

    2012-12-01

    NIR spectroscopy is used to determine acetochlor herbicide adsorption on Na-montmorillonite (NaP) and organically modified montmorillonite (NaOM). Both montmorillonites NIR spectra shows bands at 7061 and 6791 cm(-1). Organo-montmorillonite is characterised by two emphasized bands at 5871 and 5667 cm(-1) that are attributed to the fundamental overtones of the mid-IR bands at 2916 and 2850 cm(-1). Bands at 6017 and 6013 cm(-1) are attributed to acetochlor adsorbed to organo-montmorillonite and Na-montmorillonite, which is confirmed by X-ray powder diffraction (XRPD). Greater quantity of acetochlor is adsorbed to organo-clays compared to non-modified montmorillonite. Acetochlor poses high risk to environmental contamination. Organo-clays are the most useful for removing acetochlor from water and soil.

  2. Organomercury determination in biological reference materials: application to a study on mercury speciation in marine mammals off the Faröe Islands.

    PubMed

    Schintu, M; Jean-Caurant, F; Amiard, J C

    1992-08-01

    The potential use of graphite furnace atomic absorption spectrometry (GF-AAS) for the organic mercury determination in marine biological tissues was evaluated. Following its isolation by acid extraction in toluene, organic mercury was recovered in aqueous thiosulfate and measured by GF-AAS. The detection limit was 0.01 microgram Hg/g (as methyl mercury). Analyses were conducted on three reference standard materials certified for their methyl mercury content, DOLT-1, DORM-1, and TORT-1, provided by the National Research Council of Canada. The method resulted in very good recovery and reproducibility, indicating that GF-AAS can provide results comparable to those obtained by using more expensive and time consuming analytical techniques. The method was applied to the analysis of liver tissues of pilot whale specimens (Globicephala melas) from the drive fishery of the Faröe Islands (northeast Atlantic). The results provided useful information on the proportion of different mercury forms in the liver of these marine mammals.

  3. Anodic stripping voltammetry with gold electrodes as an alternative method for the routine determination of mercury in fish. Comparison with spectroscopic approaches.

    PubMed

    Giacomino, Agnese; Ruo Redda, Andrea; Squadrone, Stefania; Rizzi, Marco; Abete, Maria Cesarina; La Gioia, Carmela; Toniolo, Rosanna; Abollino, Ornella; Malandrino, Mery

    2017-04-15

    The applicability to the determination of mercury in tuna of square wave anodic stripping voltammetry (SW-ASV) conducted at both solid gold electrode (SGE) and a gold nanoparticle-modified glassy carbon electrode (AuNPs-GCE) was demonstrated. Mercury content in two certified materials and in ten samples of canned tuna was measured. The performances of the electrodes were compared with one another as well as with two spectroscopic techniques, namely cold vapour atomic absorption spectroscopy (CV-AAS) and a direct mercury analyser (DMA). The results found pointed out that both SW-ASV approaches were suitable and easy-to-use method to monitor mercury concentration in tunas, since they allowed accurate quantification at concentration values lower than the maximum admissible level in this matrix ([Hg]=1mg/kgwet weight,ww). In particular, mercury detection at the AuNPs-GCE showed a LOQ in fish-matrix of 0.1μg/l, corresponding to 0.06mg/kgww, with performance comparable to that of DMA.

  4. Evaluation of mercury mediated in vitro cytotoxicity among cell lines established from green sea turtles.

    PubMed

    Wang, Hong; Tong, Jing; Bi, Yongyi; Wang, Chunhong; Guo, Liqiao; Lu, Yuanan

    2013-04-01

    In vitro cell cultures are currently tested for their application as a biological tool for enhanced monitoring and field evaluation of environmental toxic chemical pollution. Here cell lines established from green sea turtles (GSTs) were comparatively tested for their cytotoxic responses to mercury chloride (HgCl2) exposure and also their potential use as a biological tool for effective monitoring and screening of mercury contamination in environmental waters. Following a 24-h exposure to different concentrations of mercury solution, marine turtle cells were evaluated for their cytotoxic responses using three different endpoint bioassays: tetrazolium salt reduction (MTT), neutral red uptake (NR), and Coomassie blue (CB) methods. Cytotoxic sensitivities of GST cell lines to HgCl2 were determined and compared basing on their 50% inhibition concentration (IC50) values calculated from these tests. These marine turtle cells share a very different pattern of cytotoxic sensitivities and reactions to inorganic Mercury. Among these nine turtle cell lines, turtle liver cells (GST-LV) appear to be the most tolerant one to mercury exposure while turtle lung cells (GST-LG) exhibit to be the most sensitive one. Results from this in vitro study correlate well with in vivo examination of mercury concentration in the tissues of marine turtles and are also validated and ascertained by calculated regression equations showing a significant correlation (P<0.01) between these test methods. This study also reveals the cytotoxic effect of inorganic mercury on in vitro green turtle cells and also shows GST-LG to be a cell line with potential application in field monitoring and assessing mercury contamination as a bioindicator.

  5. Determination of mercury in airborne particulate matter collected on glass fiber filters using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sampling

    NASA Astrophysics Data System (ADS)

    Araujo, Rennan G. O.; Vignola, Fabíola; Castilho, Ivan N. B.; Borges, Daniel L. G.; Welz, Bernhard; Vale, Maria Goreti R.; Smichowski, Patricia; Ferreira, Sérgio L. C.; Becker-Ross, Helmut

    2011-05-01

    A study has been undertaken to assess the capability of high-resolution continuum source graphite furnace atomic absorption spectrometry for the determination of mercury in airborne particulate matter (APM) collected on glass fiber filters using direct solid sampling. The main Hg absorption line at 253.652 nm was used for all determinations. The certified reference material NIST SRM 1648 (Urban Particulate Matter) was used to check the accuracy of the method, and good agreement was obtained between published and determined values. The characteristic mass was 22 pg Hg. The limit of detection (3σ), based on ten atomizations of an unexposed filter, was 40 ng g - 1 , corresponding to 0.12 ng m - 3 in the air for a typical air volume of 1440 m 3 collected within 24 h. The limit of quantification was 150 ng g -1, equivalent to 0.41 ng m -3 in the air. The repeatability of measurements was better than 17% RSD (n = 5). Mercury concentrations found in filter samples loaded with APM collected in Buenos Aires, Argentina, were between < 40 ng g -1 and 381 ± 24 ng g -1. These values correspond to a mercury concentration in the air between < 0.12 ng m -3 and 1.47 ± 0.09 ng m -3. The proposed procedure was found to be simple, fast and reliable, and suitable as a screening procedure for the determination of mercury in APM samples.

  6. THE DETERMINATION OF MERCURY SPECIES AND MULTIPLE METALS IN COAL COMBUSTION EMISSIONS USING IODINE-BASED IMPINGERS AND DIRECT INJECTION NEBULIZATION - INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY ANALYSIS

    EPA Science Inventory

    Mercury (Hg) emissions from coal utilities are difficult to control. Hg eludes capture by most air pollution control devices (APCDs). To determine the gaseous Hg species in stack gases, U.S. EPA Method 5 type sampling is used. In this type of sampling a hole is drilled into th...

  7. Applicability of two mobile analysers for mercury in urine in small-scale gold mining areas.

    PubMed

    Baeuml, Jennifer; Bose-O'Reilly, Stephan; Lettmeier, Beate; Maydl, Alexandra; Messerer, Katalin; Roider, Gabriele; Drasch, Gustav; Siebert, Uwe

    2011-12-01

    Mercury is still used in developing countries to extract gold from the ore in small-scale gold mining areas. This is a major health hazard for people living in mining areas. The concentration of mercury in urine was analysed in different mining areas in Zimbabwe, Indonesia and Tanzania. First the urine samples were analysed by CV-AAS (cold vapour atomic absorption spectrometry) during the field projects with a mobile mercury analyser (Lumex(®) or Seefelder(®)) and secondly, in a laboratory with a stationary CV-AAS mercury analyser (PerkinElmer(®)). Caused by the different systems (reduction agent either SnCl(2) (Lumex(®) or Seefelder(®))) or NaBH(4) (PerkinElmer(®)), with the mobile analysers only the inorganic mercury was obtained and with the stationary system the total mercury concentration was measured. The aims of the study were whether the results obtained in field with the mobile equipments can be compared with the stationary reference method in the laboratory and allow the application of these mobile analysers in screening studies on concerned populations to select those, who are exposed to critical mercury levels. Overall, the concentrations obtained with the two mobile systems were approximately 25% lower than determined with the stationary system. Nevertheless, both mobile systems seem to be very useful for screening of volunteers in field. Moreover, regional staff may be trained on such analysers to perform screening tests by themselves.

  8. Ecosystem conceptual model- Mercury

    USGS Publications Warehouse

    Alpers, Charles N.; Eagles-Smith, Collin A.; Foe, Chris; Klasing, Susan; Marvin-DiPasquale, Mark C.; Slotton, Darell G.; Windham-Myers, Lisamarie

    2008-01-01

    Mercury has been identified as an important contaminant in the Delta, based on elevated concentrations of methylmercury (a toxic, organic form that readily bioaccumulates) in fish and wildlife. There are health risks associated with human exposure to methylmercury by consumption of sport fish, particularly top predators such as bass species. Original mercury sources were upstream tributaries where historical mining of mercury in the Coast Ranges and gold in the Sierra Nevada and Klamath-Trinity Mountains caused contamination of water and sediment on a regional scale. Remediation of abandoned mine sites may reduce local sources in these watersheds, but much of the mercury contamination occurs in sediments stored in the riverbeds, floodplains, and the Bay- Delta, where scouring of Gold-Rush-era sediment represents an ongoing source.Conversion of inorganic mercury to toxic methylmercury occurs in anaerobic environments including some wetlands. Wetland restoration managers must be cognizant of potential effects on mercury cycling so that the problem is not exacerbated. Recent research suggests that wettingdrying cycles can contribute to mercury methylation. For example, high marshes (inundated only during the highest tides for several days per month) tend to have higher methylmercury concentrations in water, sediment, and biota compared with low marshes, which do not dry out completely during the tidal cycle. Seasonally inundated flood plains are another environment experiencing wetting and drying where methylmercury concentrations are typically elevated. Stream restoration efforts using gravel injection or other reworking of coarse sediment in most watersheds of the Central Valley involve tailings from historical gold mining that are likely to contain elevated mercury in associated fines. Habitat restoration projects, particularly those involving wetlands, may cause increases in methylmercury exposure in the watershed. This possibility should be evaluated.The DRERIP

  9. Laboratory-scale evaluation of various sampling and analytical methods for determining mercury emissions from coal-fired power plants

    SciTech Connect

    Agbede, R.O.; Bochan, A.J.; Clements, J.L.

    1995-11-01

    Comparative bench-scale mercury sampling method tests were performed at the Advanced Technology Systems, Inc. (ATS) laboratories for EPA Method 101A, EPA Method 29 and the Ontario Hydro Method. Both blank and impinger spiking experiments were performed. The experimental results show that the ambient level of mercury in the ATS laboratory is at or below the detection limit (10 ng Hg) as measured by a cold vapor atomic absorption spectrophotometer (CVAAS) which was used to analyze the mercury samples. From the mercury spike studies, the following observations and findings were made. (a) The recovery of mercury spikes using EPA Method 101A was 104%. (b) The Ontario Hydro Method retains about 90% of mercury spikes in the first absorbing solution but has a total spike retention of 106%. As a result, the test data shows possible migration of spiked mercury from the first impinger solution (KCI) to the permanganate impingers. (c) For the EPA Method 29 solutions, when only the peroxide impingers were spiked, mercury recoveries were 65.6% for the peroxide impingers, 0.1% for the knockout impinger and 32.8% for the permanganate impingers with an average total mercury recovery of 98.4%. At press time, data was still being obtained for both the peroxide and permanganate impinger solution spikes. This and other data will be available at the presentation.

  10. Determination of inorganic and organic priority pollutants in biosolids from meat processing industry

    SciTech Connect

    Sena, Rennio F. de Tambosi, Jose L.; Floriani, Silvia L.; Virmond, Elaine; Schroeder, Horst Fr.; Moreira, Regina F.P.M.; Jose, Humberto J.

    2009-09-15

    The biosolids (BS) generated in the wastewater treatment process of a meat processing plant were monitored and the priority pollutant content was characterized. The trace metal and organic pollutant content - polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) - were determined quantitatively and compared to guideline limits established by the US EPA and EU. PCBs were not detected in the solid samples, while trace metals, PAHs and PCDD/PCDF were detected in concentrations below the limits established by international standards. Toxic equivalent factors were evaluated for the biosolids, and the results proved that these wastes can be safely deposited on land or used in combustion/incineration plants. Since no previous data were found for meat processing waste, comparisons were made using municipal sewage sludge data reported in the literature. Since, this report monitored part of the priority pollutants established by the US EPA for meat and poultry processing wastewater and sludge, the results verified that low pollution loads are generated by the meat processing plant located in the southern part of Brazil. However, the BS generated in the treatment processes are in accordance with the limits established for waste disposal and even for soil fertilizer.

  11. Determination of inorganic elements in animal feeds by NIRS technology and a fibre-optic probe.

    PubMed

    González-Martín, Inmaculada; Alvarez-García, Noelia; González-Pérez, Claudio; Villaescusa-García, Virginia

    2006-05-15

    In the present work we study the use of near infra-red spectroscopy (NIRS) technology together with a remote reflectance fibre-optic probe for the analysis of the mineral composition of animal feeds. The method allows immediate control of the feeds without prior sample treatment or destruction through direct application of the fibre-optic probe on the sample. The regression method employed was modified partial least squares (MPLS). The calibration results obtained using forty samples of animal feeds allowed the determination of Fe, Mn, Ca, Na, K, P, Zn and Cu, with a standard error of prediction (SEP(C)) and a correlation coefficient (RSQ) of 0.129 and 0.859 for Fe; 0.175 and 0.816 for Mn; 5.470 and 0.927 for Ca; 2.717 and 0.862 for Na; 4.397 and 0.891 for K; 2.226 and 0.881 for P; 0.153 and 0.764 for Zn, and 0.095 and 0.918 for Cu, respectively. The robustness of the method was checked by applying it to 10 animal feeds samples of unknown mineral composition in the external validation.

  12. [Determination of inorganic ions in explosive residues by capillary zone electrophoresis].

    PubMed

    Feng, Junhe; Guo, Baoyuan; Lin, Jin-Ming; Xu, Jianzhong; Zhou, Hong; Sun, Yuyou; Liu, Yao; Quan, Yangke; Lu, Xiaoming

    2008-11-01

    Five anions (chlorate, perchlorate, nitrate, nitrite, and sulfate) and two cations (ammonium and potassium) in explosive residues have been separated and determined by capillary zone electrophoresis (CZE) with indirect ultraviolet detection. The electrolyte buffer for the cation separation was 10 mmol/L pyridine (pH 4.5) -3 mmol/L 18-crown-6-ether. Ammonium and potassium ions were baseline separated in less than 2.6 min with the detection limits of 0.10 mg/L and 0.25 mg/L (S/N = 3), respectively. The electrolyte buffer for the anion separation consisted of 40 mmol/L boric acid-1.8 mmol/L potassium dichromate-2 mmol/L sodium tetraborate (pH 8.6), and tetramethyl ammonium hydroxide (TMAOH) was used as electroosmotic flow modifier. All five anions were well separated in less than 4.6 min with the detection limit range of 0.10 - 1.85 mg/L (S/N = 3). The method was successfully used in real sample investigations to confirm the type of explosives.

  13. Determination of inorganic and organic priority pollutants in biosolids from meat processing industry.

    PubMed

    de Sena, Rennio F; Tambosi, José L; Floriani, Silvia L; Virmond, Elaine; Schröder, Horst Fr; Moreira, Regina F P M; José, Humberto J

    2009-09-01

    The biosolids (BS) generated in the wastewater treatment process of a meat processing plant were monitored and the priority pollutant content was characterized. The trace metal and organic pollutant content--polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF)--were determined quantitatively and compared to guideline limits established by the US EPA and EU. PCBs were not detected in the solid samples, while trace metals, PAHs and PCDD/PCDF were detected in concentrations below the limits established by international standards. Toxic equivalent factors were evaluated for the biosolids, and the results proved that these wastes can be safely deposited on land or used in combustion/incineration plants. Since no previous data were found for meat processing waste, comparisons were made using municipal sewage sludge data reported in the literature. Since, this report monitored part of the priority pollutants established by the US EPA for meat and poultry processing wastewater and sludge, the results verified that low pollution loads are generated by the meat processing plant located in the southern part of Brazil. However, the BS generated in the treatment processes are in accordance with the limits established for waste disposal and even for soil fertilizer.

  14. [Mercury content of mushrooms (author's transl)].

    PubMed

    Seeger, R

    1976-01-01

    The mercury content of 236 species of wild mushrooms was determined by flameless atomic absorption spectroscopy. Of each species several samples--altogether 616--were tested. The mercury content was between 0.04 and 21.60 mg/kg dry weight, equivalent to 0.002 and 3.090 mg/kg fresh weight. The mercury content was clearly species-dependent. Mercury-rich species particularly were found in Tricholomataceae, Agaricaceae and Lycoperdaceae, whereas in Boletaceae, Amanitaceae and Russulaceae mercury-rich species were rather rare. There was a considerable variability within species, too; hence, other factors, yet unknown, must also determine the mercury content. Geographical influences were not demonstrable. All mushrooms grown on wood had a very low mercury content. Storing over several years did not diminish the mercury content of dried mushrooms. The highest mercury content was found in a poisonous mushroom, but on the average, poisonous mushrooms contained less mercury than edible ones.

  15. Inorganic Arsenic Determination in Food: A Review of Analytical Proposals and Quality Assessment Over the Last Six Years.

    PubMed

    Llorente-Mirandes, Toni; Rubio, Roser; López-Sánchez, José Fermín

    2017-01-01

    Here we review recent developments in analytical proposals for the assessment of inorganic arsenic (iAs) content in food products. Interest in the determination of iAs in products for human consumption such as food commodities, wine, and seaweed among others is fueled by the wide recognition of its toxic effects on humans, even at low concentrations. Currently, the need for robust and reliable analytical methods is recognized by various international safety and health agencies, and by organizations in charge of establishing acceptable tolerance levels of iAs in food. This review summarizes the state of the art of analytical methods while highlighting tools for the assessment of quality assessment of the results, such as the production and evaluation of certified reference materials (CRMs) and the availability of specific proficiency testing (PT) programmes. Because the number of studies dedicated to the subject of this review has increased considerably over recent years, the sources consulted and cited here are limited to those from 2010 to the end of 2015.

  16. Mercury: Determining Minerals And Their Abundances With Mid-IR Spectral Deconvolution III

    NASA Astrophysics Data System (ADS)

    Sprague, Ann L.; Donaldson Hanna, K.; Kozlowski, R. W.; Helbert, J.; Maturilli, A.; Grosse, F. A.; Boop, T. S.; Boccafola, K.

    2007-10-01

    We identify mineral types and approximate abundances on Mercury's surface from 196° to 270°W longitude from five slit observations at regions in north-mid and north latitudes. The subtending slit sectors have central coordinates as follows: (1) 11 April 2006#89; 203°W, 13°N 205°W, 47°N (2) 7 April 2006#77; 210°W, 8°N 230°W, 25°N (3) 11 April 2006#96; 212°W, 15°N 219°W, 45°N (4) 11 April 2006#93; 225°W, 13°N 237°W, 45°N (5) 11 April 2006#109; 262°W, 8°N, 267°W, 25°N. Our results are obtained by modeling spectra obtained with the Mid-Infrared Spectrometer and Imager (MIRSI) at the Infrared Telescope Facility (IRTF) using an established spectral deconvolution algorithm (Ramsey 1996, Ph.D. Dissertation, ASU; Ramsey and Christiansen 1998, JGR). We have assembled several mineral libraries (JHU, Salisbury et al. 1991; JPL, http://speclib.jpl.nasa.gov; RELAB, http://www.planetary brown.edu/relab; ASU, http://speclib.asu.edu; BED, Maturilli et al. 2007, LPSC XXXVIII Abs.) consisting of a wide range of known mineral compositions with grain sizes ranging from the finest separates, 0 - 45 µm, incrementally increasing to 250 - 400 µm. Surface mineral deconvolutions are suggestive of albite, enstatite, clinopyroxene, labradorite, and sodalite, mineral phases that have been previously observed in the mid-infrared at Mercury (Sprague et al. 1994, 1998, Icarus). The deconvolution also identified pigeonite at more than one location. The same techniques and computer program have correctly fit the known compositions of the HED samples, and given a plausible fit to spectra from the Moon (both also presented at this meeting). This work was funded by NSF AST0406796.

  17. Mercury and Your Health

    MedlinePlus

    ... 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 ...

  18. An overview of recent applications of inductively coupled plasma-mass spectrometry (ICP-MS) in determination of inorganic impurities in drugs and pharmaceuticals.

    PubMed

    Nageswara Rao, R; Talluri, M V N Kumar

    2007-01-04

    The recent applications of inductively coupled plasma-mass spectrometry (ICP-MS) in determination of trace level inorganic impurities in drugs and pharmaceuticals have been reviewed. ICP-MS coupled with LC, GC and CE was used for speciation of heavy metals in pharmaceutical products. The review covers the period from 1995 to 2005 during which the technique was applied not only for determination of metallic impurities but also the assay of various trace elements in pharmaceuticals.

  19. Chronic mercury poisoning: Report of two siblings.

    PubMed

    Yilmaz, Cahide; Okur, Mesut; Geylani, Hadi; Caksen, Hüseyin; Tuncer, Oğuz; Ataş, Bülent

    2010-01-01

    Mercury exists as organic inorganic and elementary forms in nature and is one of the most toxic metals that are poisonous for human beings. Mercury is commonly used in many different sectors of industry such as in insects formulas, agriculture products, lamps, batteries, paper, dyes, electrical/electronic devices, jewelry, and in dentistry. In this study, two siblings (one a 7-year-old boy and the other a 13 years old girl) are reported who developed chronic mercury poisoning as a result of long-term contact with batteries. Our aim is to emphasize the importance of mercury poisoning that is extremely rarely seen in childhood.

  20. MWCNTs based high sensitive lateral flow strip biosensor for rapid determination of aqueous mercury ions.

    PubMed

    Yao, Li; Teng, Jun; Zhu, Mengya; Zheng, Lei; Zhong, Youhao; Liu, Guodong; Xue, Feng; Chen, Wei

    2016-11-15

    Here, we describe a disposable multi-walled carbon nanotubes (MWCNTs) labeled nucleic acid lateral flow strip biosensor for rapid and sensitive detection of aqueous mercury ions (Hg(2+)). Unlike the conventional colloidal gold nanoparticle based strip biosensors, the carboxylated MWCNTs were selected as the labeling substrate because of its high specific surface area for immobilization of recognition probes, improved stability and enhanced detection sensitivity of the strip biosensor. Combining the sandwich-type of T-Hg(2+)-T recognition mechanism with the optical properties of MWCNTs on lateral flow strip, optical black bands were observed on the lateral flow strips. Parameters (such as membrane category, the MWCNTs concentration, the amount of MWCNT-DNA probe, and the volume of the test probe) that govern the sensitivity and reproducibility of the sensor were optimized. The response of the optimized biosensor was highly linear over the range of 0.05-1ppb target Hg(2+), and the detection threshold was estimated at 0.05 ppb within a 15-min assay time. The sensitivity was 10-fold higher than the conventional colloidal gold based strip biosensor. More importantly, the stability of the sensor was also greatly improved with the usage of MWCNTs as the labeling.

  1. Use of stable isotope signatures to determine mercury sources in the Great Lakes

    USGS Publications Warehouse

    Lepak, Ryan F.; Yin, Runsheng; Krabbenhoft, David P.; Ogorek, Jacob M.; DeWild, John F.; Holsen, Thomas M.; Hurley, James P.

    2015-01-01

    Sources of mercury (Hg) in Great Lakes sediments were assessed with stable Hg isotope ratios using multicollector inductively coupled plasma mass spectrometry. An isotopic mixing model based on mass-dependent (MDF) and mass-independent fractionation (MIF) (δ202Hg and Δ199Hg) identified three primary Hg sources for sediments: atmospheric, industrial, and watershed-derived. Results indicate atmospheric sources dominate in Lakes Huron, Superior, and Michigan sediments while watershed-derived and industrial sources dominate in Lakes Erie and Ontario sediments. Anomalous Δ200Hg signatures, also apparent in sediments, provided independent validation of the model. Comparison of Δ200Hg signatures in predatory fish from three lakes reveals that bioaccumulated Hg is more isotopically similar to atmospherically derived Hg than a lake’s sediment. Previous research suggests Δ200Hg is conserved during biogeochemical processing and odd mass-independent fractionation (MIF) is conserved during metabolic processing, so it is suspected even is similarly conserved. Given these assumptions, our data suggest that in some cases, atmospherically derived Hg may be a more important source of MeHg to higher trophic levels than legacy sediments in the Great Lakes.

  2. Distribution of total mercury and methyl mercury in water, sediment, and fish from South Florida estuaries

    USGS Publications Warehouse

    Kannan, K.; Smith, R.G.; Lee, R.F.; Windom, H.L.; Heitmuller, P.T.; Macauley, J.M.; Summers, J.K.

    1998-01-01

    Concentrations of total mercury and methyl mercury were determined in sediment and fish collected from estuarine waters of Florida to understand their distribution and partitioning. Total mercury concentrations in sediments ranged from 1 to 219 ng/g dry wt. Methyl mercury accounted for, on average, 0.77% of total mercury in sediment. Methyl mercury concentrations were not correlated with total mercury or organic carbon content in sediments. The concentrations of total mercury in fish muscle were between 0.03 and 2.22 (mean: 0.31) ??g/g, wet wt, with methyl mercury contributing 83% of total mercury. Methyl mercury concentrations in fish muscle were directly proportional to total mercury concentrations. The relationship of total and methyl mercury concentrations in fish to those of sediments from corresponding locations was fish-species dependent, in addition to several abiotic factors. Among fish species analyzed, hardhead catfish, gafftopsail catfish, and sand seatrout contained the highest concentrations of mercury. Filtered water samples from canals and creeks that discharge into the Florida Bay showed mercury concentrations of 3-7.4 ng/L, with methyl mercury accounting for <0.03-52% of the total mercury. Consumption of fish containing 0.31 ??g mercury/g wet wt, the mean concentration found in this study, at rates greater than 70 g/day, was estimated to be hazardous to human health.

  3. On-line HPLC-UV/Nano-TiO2-ICPMS system for the determination of inorganic selenium species.

    PubMed

    Sun, Y C; Chang, Y C; Su, C K

    2006-04-15

    We have developed an UV/nano-TiO2 vapor generation (VG) device that when coupled between a chromatographic column and an ICP mass spectrometer provides a simple and sensitive hyphenated method for the determination of Se(IV) and Se(VI) without the need to use conventional chemical VG techniques. Because our proposed VG device allows both Se(IV) and Se(VI) species in the column effluent to be converted on-line into volatile Se products, which are then measured directly by the ICPMS, the safety risks and the probability of contamination arising from the use of additional chemicals are both low. To achieve the maximum signal intensity, we optimized a number of the operating parameters of the UV/nano-TiO2 VG device, including the acidity, the amounts of TiO2 and formic acid, and the length of the reaction coil, with respect to their effects on the reduction efficiency of the analyte species. This hyphenated method achieves excellent detection limits-0.06 and 0.03 ng mL(-1) for Se(IV) and Se(VI), respectively-because of the high efficiencies of the conversions of Se(IV) and Se(VI) to their respective volatile products and the lower blank level achieved, relative to those of other traditional systems. In addition, because the conversion efficiency of the analyte selenium species reached its maximum level within 36 s of irradiation, the working time (approximately 12 min) was limited primarily by time required for the chromatographic separation. A series of validation experiments-analysis of the 1643e Standard Reference Material and natural water samples-indicated that our proposed methods can be applied satisfactorily to the determination of inorganic selenium species in water samples.

  4. Optimization and validation of a rapid method to determine citrate and inorganic phosphate in milk by capillary electrophoresis.

    PubMed

    Izco, J M; Tormo, M; Harris, A; Tong, P S; Jimenez-Flores, R

    2003-01-01

    Quantification of phosphate and citrate compounds is very important because their distribution between soluble and colloidal phases of milk and their interactions with milk proteins influence the stability and some functional properties of dairy products. The aim of this work was to optimize and validate a capillary electrophoresis method for the rapid determination of these compounds in milk. Various parameters affecting analysis have been optimized, including type, composition, and pH of the electrolyte, and sample extraction. Ethanol, acetonitrile, sulfuric acid, water at 50 degrees C or at room temperature were tested as sample buffers (SB). Water at room temperature yielded the best overall results and was chosen for further validation. The extraction time was checked and could be shortened to less than 1 min. Also, sample preparation was simplified to pipet 12 microl of milk into 1 ml of water containing 20 ppm of tartaric acid as an internal standard. The linearity of the method was excellent (R2 > 0.999) with CV values of response factors <3%. The detection limits for phosphate and citrate were 5.1 and 2.4 nM, respectively. The accuracy of the method was calculated for each compound (103.2 and 100.3%). In addition, citrate and phosphate content of several commercial milk samples were analyzed by this method, and the results deviated less than 5% from values obtained when analyzing the samples by official methods. To study the versatility of the technique, other dairy productssuch as cream cheese, yogurt, or Cheddar cheese were analyzed and accuracy was similar to milk in all products tested. The procedure is rapid and offers a very fast and simple sample preparation. Once the sample has arrived at the laboratory, less than 5 min (including handling, preparation, running, integration, and quantification) are necessary to determine the concentration of citric acid and inorganic phosphate. Because of the speed and accuracy of this method, it is promising as an

  5. Chromatic analysis by monitoring unmodified silver nanoparticles reduction on double layer microfluidic paper-based analytical devices for selective and sensitive determination of mercury(II).

    PubMed

    Meelapsom, Rattapol; Jarujamrus, Purim; Amatatongchai, Maliwan; Chairam, Sanoe; Kulsing, Chadin; Shen, Wei

    2016-08-01

    This study demonstrates chromatic analysis based on a simple red green blue (RGB) color model for sensitive and selective determination of mercury(II). The analysis was performed by monitoring the color change of a microfluidic Paper-based Analytical Device (µPAD). The device was fabricated by using alkyl ketene dimer (AKD)-inkjet printing and doped with unmodified silver nanoparticles (AgNPs) which were disintegrated when being exposed to mercury(II). The color intensity was detected by using an apparatus consisting of a digital camera and a homemade light box generating constant light intensity. A progressive increase in color intensity of the tested area on the µPAD (3.0mm) was observed with increasing mercury(II) concentration. The developed system enabled quantification of mercury(II) at low concentration with the detection limit of 0.001mgL(-1) (3 SD blank/slope of the calibration curve) and small sample volume uptake (2µL). The linearity range of the calibration curve in this technique was demonstrated from 0.05 to 7mgL(-1) (r(2)=0.998) with good precision (RSD less than 4.1%). Greater selectivity towards mercury(II) compared with potential interference ions was also observed. Furthermore, the percentage recoveries of spiked water samples were in an acceptable range which was in agreement with the values obtained from the conventional method utilizing cold vapor atomic absorption spectrometer (CVAAS). The proposed technique allows a rapid, simple, sensitive and selective analysis of trace mercury(II) in water samples.

  6. Mercury in the Pelagic Food Web of Lake Champlain

    PubMed Central

    Chen, Celia; Kamman, Neil; Shanley, James; Chalmers, Ann; Jackson, Brian; Taylor, Vivien; Smeltzer, Eric; Stangel, Pete; Shambaugh, Angela

    2013-01-01

    Lake Champlain continues to experience mercury contamination resulting in public advisories to limit human consumption of top trophic level fish such as walleye. Prior research suggested that mercury levels in biota could be modified by differences in ecosystem productivity as well as mercury loadings. We investigated relationships between mercury in different trophic levels in Lake Champlain. We measured inorganic and methyl mercury in water, seston, and two size fractions of zooplankton from 13 sites representing a range of nutrient loading conditions and productivity. Biomass varied significantly across lake segments in all measured ecosystem compartments in response to significant differences in nutrient levels. Local environmental factors such as alkalinity influenced the partitioning of mercury between water and seston. Mercury incorporation into biota was influenced by the biomass and mercury content of different ecosystem strata. Pelagic fish tissue mercury was a function of fish length and the size of the mercury pool associated with large zooplankton. We used these observations to parameterize a model of mercury transfers in the Lake Champlain food web that accounts for ecosystem productivity effects. Simulations using the mercury trophic transfer model suggest that reductions of 25 to 75% in summertime dissolved eplimnetic total mercury will likely allow fish tissue mercury concentrations to drop to the target level of 0.3 µg g−1 in a 40-cm fish in all lake segments. Changes in nutrient loading and ecosystem productivity in eutrophic segments may delay any response to reduced dissolved mercury and may result in increases in fish tissue mercury. PMID:22193540

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

    NASA Technical Reports Server (NTRS)

    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.

  8. FINAL REPORT ON THE AQUATIC MERCURY ASSESSMENT STUDY

    SciTech Connect

    Halverson, N

    2008-09-30

    In February 2000, the United States Environmental Protection Agency (EPA) Region 4 issued a proposed Total Maximum Daily Load (TMDL) for total mercury in the middle and lower Savannah River. The initial TMDL, which would have imposed a 1 ng/l mercury limit for discharges to the middle/lower Savannah River, was revised to 2.8 ng/l in the final TMDL released in February 2001. The TMDL was intended to protect people from the consumption of contaminated fish, which is the major route of mercury exposure to humans. The most bioaccumulative form of mercury is methylmercury, which is produced in aquatic environments by the action of microorganisms on inorganic mercury. Because of the environmental and economic significance of the mercury discharge limits that would have been imposed by the TMDL, the Savannah River Site (SRS) initiated several studies concerning: (1) mercury in SRS discharges, SRS streams and the Savannah River, (2) mercury bioaccumulation factors for Savannah River fish, (3) the use of clams to monitor the influence of mercury from tributary streams on biota in the Savannah River, and (4) mercury in rainwater falling on the SRS. The results of these studies are presented in detail in this report. The first study documented the occurrence, distribution and variation of total and methylmercury at SRS industrial outfalls, principal SRS streams and the Savannah River where it forms the border with the SRS. All of the analyses were performed using the EPA Method 1630/31 ultra low-level and contaminant-free techniques for measuring total and methylmercury. Total mercury at National Pollutant Discharge Elimination System (NPDES) outfalls ranged from 0.31-604 ng/l with a mean of 8.71 ng/l. Mercury-contaminated groundwater was the source for outfalls with significantly elevated mercury concentrations. Total mercury in SRS streams ranged from 0.95-15.7 ng/l. Mean total mercury levels in the streams varied from 2.39 ng/l in Pen Branch to 5.26 ng/l in Tims Branch

  9. Preconcentration and determination of mercury(II) at a chemically modified electrode containing 3-(2-thioimidazolyl)propyl silica gel.

    PubMed

    Dias Filho, Newton L; do Carmo, Devaney R; Caetano, Laércio; Rosa, André H

    2005-11-01

    A mercury-sensitive chemically modified graphite paste electrode was constructed by incorporating modified silica gel into a conventional graphite paste electrode. The functional group attached to the (3-chloropropyl) silica gel surface was 2-mercaptoimidazole, giving a new product denoted by 3-(2-thioimidazolyl)propyl silica gel, which is able to complex mercury ions. Mercury was chemically adsorbed on the modified graphite paste electrode containing 3-(2-thioimidazolyl)propyl silica (TIPSG GPE) by immersion in a Hg(II) solution, and the resultant surface was characterized by cyclic and differential pulse anodic stripping voltammetry. One cathodic peak at 0.1 V and other anodic peak at 0.34 V were observed on scanning the potential from -0.1 to 0.8 V (0.01 M KNO3; v = 2.0 mV s(-1) vs. Ag/AgCl). The anodic peak at 0.34 V show an excellent sensitivity for Hg(II) ions in the presence of several foreign ions. A calibration graph covering the concentration range from 0.02 to 2 mg L(-1) was obtained. The detection limit was estimated to be 5 microg L(-1). The precision for six determinations of 0.05 and 0.26 mg L(-1) Hg(II) was 3.0 and 2.5% (relative standard deviation), respectively. The method can be used to determine the concentration of mercury(II) in natural waters contaminated by this metal.

  10. Determination of lead, cadmium and mercury in microwave-digested foodstuffs by RP-HPLC with an on-line enrichment technique.

    PubMed

    Huang, Zhangjie; Yang, Guangyu; Hu, Qiufen; Yin, Jiayuan

    2003-02-01

    A new method for the simultaneous determination of lead, cadmium and mercury ions in microwave-digested foodstuffs by reversed-phase high-performance liquid chromatography combined with on-line enrichment technique has been developed. The foodstuff samples were digested by microwave digestion. The lead, cadmium and mercury ions can be precolumn derivatized with 5,10,15,20-tetrakis(3-aminophenyl)porphine (T3APP) to form color chelates; then, the Hg-T3APP, Cd-T3APP and Pb-T3APP chelates can be enriched and separated on a valve switching HPLC system combined with on-line enrichment technique. The linearity ranges are 0.01-120 microg/l for each metal ion. The detection limits (S/N = 3) of lead, cadmium and mercury are 1.2 ng/l, 0.5 ng/l and 0.8 ng/l, respectively. This method was applied to the determination of lead, cadmium and mercury in foodstuffs with good results.

  11. Clean conditions for the determination of ultra-low levels of mercury in ice and snow samples.

    PubMed

    Ferrari, C P; Moreau, A L; Boutron, C F

    2000-03-01

    Laboratory facilities and methods are presented for the determination of ultra-low levels of mercury (Hg) in ice and snow samples originating from polar ice caps or temperate regions. Special emphasis will be given to the presentation of the clean laboratory and the cleaning procedures. The laboratory is pressurized with air filtered through high efficiency particle filters. This first filtration is not enough to get rid of contamination by Hg in air. Experiments are conducted in a clean bench, especially built for Hg analysis, equipped with both particle filter and activated charcoal filter. It allows to obtain very low levels of atmospheric Hg contamination. Ultrapure water is produced for cleaning all the plastic containers that will be used for ice and snow samples and also for the dilution of the standards. Hg content in laboratory water is about 0.08+/-0.02 pg/g. A Teflon system has been developed for the determination of Hg in ice and snow samples based on Hg(II) reduction to Hg(0) with a SnCl2/HNO3 solution followed by the measurement of gaseous Hg(0) with a Hg analyzer GARDIS 1A+ based on the Cold Vapor Atomic Absorption Spectroscopy method. Blank determination is discussed.

  12. Biotoxicity of mercury as influenced by mercury(II) speciation.

    PubMed

    Farrell, R E; Germida, J J; Huang, P M

    1990-10-01

    Integration of physicochemical procedures for studying mercury(II) speciation with microbiological procedures for studying the effects of mercury on bacterial growth allows evaluation of ionic factors (e.g., pH and ligand species and concentration) which affect biotoxicity. A Pseudomonas fluorescens strain capable of methylating inorganic Hg(II) was isolated from sediment samples collected at Buffalo Pound Lake in Saskatchewan, Canada. The effect of pH and ligand species on the toxic response (i.e., 50% inhibitory concentration [IC50]) of the P. fluorescens isolated to mercury were determined and related to the aqueous speciation of Hg(II). It was determined that the toxicities of different mercury salts were influenced by the nature of the co-ion. At a given pH level, mercuric acetate and mercuric nitrate yielded essentially the same IC50s; mercuric chloride, on the other hand, always produced lower IC50s. For each Hg salt, toxicity was greatest at pH 6.0 and decreased significantly (P = 0.05) at pH 7.0. Increasing the pH to 8.0 had no effect on the toxicity of mercuric acetate or mercuric nitrate but significantly (P = 0.05) reduced the toxicity of mercuric chloride. The aqueous speciation of Hg(II) in the synthetic growth medium M-IIY (a minimal salts medium amended to contain 0.1% yeast extract and 0.1% glycerol) was calculated by using the computer program GEOCHEM-PC with a modified data base. Results of the speciation calculations indicated that complexes of Hg(II) with histidine [Hg(H-HIS)HIS+ and Hg(H-HIS)2(2+)], chloride (HgCl+, HgCl2(0), HgClOH0, and HgCl3-), phosphate (HgHPO4(0), ammonia (HgNH3(2+), glycine [Hg(GLY)+], alanine [Hg(ALA)+], and hydroxyl ion (HgOH+) were the Hg species primarily responsible for toxicity in the M-IIY medium. The toxicity of mercuric nitrate at pH 8.0 was unaffected by the addition of citrate, enhanced by the addition of chloride, and reduced by the addition of cysteine. In the chloride-amended system, HgCl+, HgCl2(0), and Hg

  13. Atomic-absorption determination of mercury in geological materials by flame and carbon-rod atomisation after solvent extraction and using co-extracted silver as a matrix modifier

    USGS Publications Warehouse

    Sanzolone, R.F.; Chao, T.T.

    1983-01-01

    Based on modifications and expansion of the original Tindall's solvent extraction flame atomic-absorption procedure, an atomic-absorption spectrophotometric method has been developed for the determination of mercury in geological materials. The sample is digested with nitric and hydrochloric acids in a boiling water-bath. The solution is made ammoniacal and potassium iodide and silver nitrate are added. The mercury is extracted into isobutyl methyl ketone as the tetraiodomercurate(ll). Added silver is co-extracted with mercury and serves as a matrix modifier in the carbon-rod atomiser. The mercury in the isobutyl methyl ketone extract may be determined by either the flame- or the carbon-rod atomisation method, depending on the concentration level. The limits of determination are 0.05-10 p.p.m. of mercury for the carbon-rod atomisation and 1 -200 p.p.m. of mercury for the flame atomisation. Mercury values for reference samples obtained by replicate analyses are in good agreement with those reported by other workers, with relative standard deviations ranging from 2.3 to 0.9%. Recoveries of mercury spiked at two levels were 93-106%. Major and trace elements commonly found in geological materials do not interfere.

  14. Mercury toxicity and neurodegenerative effects.

    PubMed

    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

  15. Preliminary Study: Application of Off-Axis ICOS to Determine Stable Carbon Isotope in Dissolved Inorganic Carbon

    NASA Astrophysics Data System (ADS)

    Kim, Y. T.; Lee, J. M.; Hwang, J. H.; Piao, J.; Woo, N. C.

    2015-12-01

    CO2 is one of the major causes for global climate change. Because stable carbon isotope ratio is used to trace carbon source, several analytical techniques likes IRMS (Isotope Ratio Mass Spectrometry) and LAS (Laser Absorption Spectrometry) were extensively used. Off-axis ICOS, a kind of LAS, has merits on long-term stability and field application, therefore it is widely being used in CCS (Carbon Capture and Storage) field. The aim of this study is to extend the application scope of OA-ICOS to determine dissolved inorganic carbon (DIC). Because OA-ICOS showed dependence of δ13C on CO2 concentration, data processing is required. We tested CO2 Carbon Isotope Analyzer (CCIA-36-EP, Los Gatos Research) with both reference gas (δ13C= -28.28‰) and aqueous solutions prepared by dissolving sodium bicarbonate standards (δ13C= -12.26‰ and +3.96‰). The differences of δ13C between reference and measurement values are plotted by CO2 concentrations, then compared. At first, we checked the similarity between our curve pattern for reference gas and Guillon's research (δ13C= -43.99‰) by other Analyzer. To analyze aqueous samples, more errors can be caused than gas analysis. The carbon isotope fractionation occurs during dissolving standard reagents and extracting DIC as CO2 gas form. This effect is mixed with CO2 concentration dependence effect, therefore the curve patterns are different with that for reference gas. Our experiments are done for various δ13C values. It could be an important point to use OA-ICOS to analyze DIC, too.

  16. Mercury and methylmercury contamination in surficial sediments and clams of a coastal lagoon (Pialassa Baiona, Ravenna, Italy)

    NASA Astrophysics Data System (ADS)

    Trombini, Claudio; Fabbri, Daniele; Lombardo, Marco; Vassura, Ivano; Zavoli, Elisabetta; Horvat, Milena

    2003-11-01

    The Ramsar site Pialassa Baiona is an intertidal brackish lagoon lying 5 km north of the city of Ravenna and covering a surface area of about 1100 ha. From 1958 to 1976 Pialassa Baiona was heavily impacted by industrial pollution; mercury, polycyclic aromatic hydrocarbons, polymers were among the most important pollutants which nowadays contaminate the sedimentary compartment. Following earlier investigations on total mercury (THg) distribution and bioavailability, this study is focused on mercury speciation in sediments and clams. Methylmercury ( MMHg) concentrations were determined in surface sediments (0-5 cm) in different seasons, and compared to THg. Selected sediments were subjected to a sequential extraction procedure to study solid state THg distribution. Operationally, three fractions of inorganic mercury were defined: mobile mercury ( Hgm), humic acid complexed mercury ( Hgha), and sulphide-bound mercury ( Hgs). THg and MMHg concentrations in sediments ranged in the 0.2-250 μg g -1 and 0.13-45 ng g -1 d.w. intervals, respectively. MMHg/THg ratios were higher in summer as well as in sites where the THg burden was lower; the highest MMHg/THg values were observed in Chiaro del Pontazzo, an area subjected to a drastic reduction of salinity. THg and MMHg concentrations were also determined in tissues of clams ( Tapes philippinarum) collected in the lagoon. MMHg in clams felt in the 180-470 ng g -1 interval and accounts for 72-95% of tissue THg.

  17. Determination of mercury in ash and soil samples by oxygen flask combustion method--cold vapor atomic fluorescence spectrometry (CVAFS).

    PubMed

    Geng, Wenhua; Nakajima, Tsunenori; Takanashi, Hirokazu; Ohki, Akira

    2008-06-15

    A simple method was developed for the determination of mercury (Hg) in coal fly ash (CFA), waste incineration ash (WIA), and soil by use of oxygen flask combustion (OFC) followed by cold vapor atomic fluorescence spectrometry (CVAFS). A KMnO4 solution was used as an absorbent in the OFC method, and the sample containing a combustion agent and an ash or soil sample was combusted by the OFC method. By use of Hg-free graphite as the combustion agent, the determination of Hg in ash and soil was successfully carried out; the Hg-free graphite was prepared by use of a mild pyrolysis procedure at 500 degrees C. For six certified reference materials (three CFA samples and three soil samples), the values of Hg obtained by this method were in good agreement with the certified or reference values. In addition, real samples including nine CFAs collected from some coal-fired power plants, five WIAs collected from waste incineration plants, and two soils were analyzed by the present method, and the data were compared to those from microwave-acid digestion (MW-AD) method.

  18. Immersed single-drop microextraction-electrothermal vaporization atomic absorption spectroscopy for the trace determination of mercury in water samples.

    PubMed

    Bagheri, Habib; Naderi, Mehrnoush

    2009-06-15

    A new method based on single-drop microextraction (SDME) combined with electrothermal vaporization atomic absorption spectroscopy (ETV-AAS) was developed for the trace determination of mercury in water samples. A microdrop of m-xylene was applied as the extraction solvent. After extraction, the microdrop was introduced, directly, into a graphite furnace of AAS. Some important extraction parameters such as type of solvent, volume of solvent, sample stirring, ionic strength, sample pH, chelating agent concentration, sample temperature, and extraction time were investigated and optimized. The highest possible microdrop volume of 10 microL, a sampling temperature of 27 degrees C, and use of m-xylene containing dithizone, as complexing agent, are major parameters led to achieve a high enrichment factor of 970. Under the optimized conditions, the detection limit of the method was 0.01 microg L(-1) and the relative standard deviation was 6.1% (n=7). The proposed method has been successfully applied to the determination of Hg in two river water samples. The effects of interfering species such as Pt, Pd, Cu, Au, and Bi, having the tendency to form complexes with dithizone, at two concentration levels of 100 and 1000 microg L(-1) were also studied.

  19. Retention of mercury by salmon

    USGS Publications Warehouse

    Amend, Donald F.

    1970-01-01

    Consuming fish that have been exposed repeatedly to mercury derivatives is a potential public health hazard because fish can accumulate and retain mercury in their tissues (Rucker, 1968). Concern has been expressed in the United States because mercurials have been used extensively in industry and as prophylactic and therapeutic agents in fish hatcheries. Rucker and Amend (1969) showed that yearling rainbow trout (Salmo gairdneri) and chinook salmon (Oncorhynchus tshawytscha) exposed to mercurials accumulated excessive amounts of mercury in many tissues. Further, Rucker and Amend (1969) concluded that wild fish that ate mercury-contaminated fish also could contain high mercury levels. Although mercury was eliminated from most tissues within several months, substantial levels remained in the kidney for more than 33 weeks after the last exposure. Since high levels of mercury can be retained in the kidney for an undetermined time, it is possible that returning adult salmon exposed to mercurials as juveniles could constitute a potential hazard to public health. The purpose of this study was to determine whether such fish contained high residual levels of mercury.

  20. Got Mercury?

    NASA Technical Reports Server (NTRS)

    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

  1. [Determination of inorganic elements in five kinds of Mongolia medicines by high pressure sealed microwave digestion-ICP-AES].

    PubMed

    Sagara; Zhaorigetu; Dong, Guo-Liang; Zhang, Jing-Xia

    2008-07-01

    Five kinds of Mongolia medicines, Eridun-Urile, Deduhonghuaqiweiwan, Tonglage-5, Uzhumu-7 and Geiwang-9 are digested with HNO3-HClO4 system by high pressure system-sealed Microwave Digestion. The 17 inorganic elements content of magnesium, aluminum, calcium, chromium, manganese, ferrum, cobalt, nickel, copper, zincum, arsenic, selenium, strontium, molybdenum, silver, cadmium, plumbum in the solution are determined by ICP-AES. The results are proved to be reliable by adding standard recovery experiment. The recovery is 97.48%-103.01% for Mg, 102.71%-105.60% for Al, 102.00%-105.53% for Ca, 98.78%-100.34% for Cr, 101.93%-104.65% for Mn, 100.34%-104.51% for Fe, 103.13%-105.46% for Co, 100.07%-103.22% for Ni, 97.25%-99.06% for Cu, 98.57%-100.10% for Zn, 102.35%-105.37% for As, 100.24%-104.59% for Se, 99.19%-102.70% for Sr, 103.35%-105.78% for Mo, 99.65%-101.32% for Ag, 102.73%-105.32% for Cd, and 104.76%-106.35% for Pb by this method. The relative standard deviation is less than 3.3% for all the elements. And the method has high accuracy and good precision The determination results indicate that the content of element in Five Kinds of Mongolia Medicines is 0-15 microg x g(-1) for Cd, Ag, As, Pb, Co, Ni, Cu; 15-100 microg x g(-1) for Mo, Se, Zn, Cr; 100-3 000 microg x g(-1) for Mn, Sr, Fe, Mg, Al; 3 000-8 000 microg x g(-1) for Ca. Among of the five kinds of mongolia medicines, the content of elements has great differences. The order is Ca > Mg > Al > Fe > Mn > Sr > Se > Zn > Mo > Cu > Pb > As >Cr > Ni > Co > Cd > Ag for Eridun-Urile; Ca > Al > Fe > Mg > Mn > Sr > Se > Mo > Zn > Ni > Cr > Cu > Pb > As > Co > Cd > Ag for Deduhonghuaqiweiwan; Ca > Fe > Mg > Al > Mn > Sr > Se > Zn > Mo > Cr > Ni > Cu > Pb > As > Co > Cd > Ag for Tonglage-5, Ca > Al > Mg > Fe > Sr > Mn > Se > Zn > Co > Mo > Cr > Cu > Pb > As > Ag > Ni > Cd for Uzhumu-7 and Mg > Ca > Al > Fe > Se > Mn > Zn > Sr > Mo > Cu > Cr > Pb >As > Ag > Co = Cd = Ni for Geiwang-9. The content of common elements Ca, Mg

  2. Control of mercury pollution.

    PubMed

    Noyes, O R; Hamdy, M K; Muse, L A

    1976-01-01

    When a 203Ng(NO3)2 solution was kept at 25 degrees C in glass or polypropylene containers, 50 and 80% of original radioactivity was adsorbed to the containers' walls after 1 and 4 days, respectively. However, no loss in radioactivity was observed if the solution was supplemented with HgCl as carrier (100 mug Hg2+/ml) and stored in either container for 13 days. When 203Hg2+ was dissolved in glucose basal salt broth with added carrier, levels of 203Hg2+ in solution (kept in glass) decreased to 80 and 70% of original after 1 and 5 days and decreased even more if stored in polypropylene (60 and 40% of original activity after 1 and 4 days, respectively). In the absence of carrier, decreases of 203Hg2+ activities in media stored in either container were more pronounced due to chemisorption (but) not diffusion. The following factors affecting the removal of mercurials from aqueous solution stored in glass were examined: type and concentration of adsorbent (fiber glass and rubber powder); pH; pretreatment of the rubber; and the form of mercury used. Rubber was equally effective in the adsorption of organic and inorganic mercury. The pH of the aqueous 203Hg2+ solution was not a critical factor in the rate of adsorption of mercury by the rubber. In addition, the effect of soaking the rubber in water for 18 hr did not show any statistical difference when compared with nontreated rubber. It can be concluded that rubber is a very effective adsorbent of mercury and, thus, can be used as a simple method for control of mercury pollution.

  3. Potential application of a semi-quantitative method for mercury determination in soils, sediments and gold mining residues.

    PubMed

    Yallouz, A V; Cesar, R G; Egler, S G

    2008-02-01

    An alternative, low cost method for analyzing mercury in soil, sediment and gold mining residues was developed, optimized and applied to 30 real samples. It is semiquantitative, performed using an acid extraction pretreatment step, followed by mercury reduction and collection in a detecting paper containing cuprous iodide. A complex is formed with characteristic color whose intensity is proportional to mercury concentration in the original sample. The results are reported as range of concentration and the minimum detectable is 100 ng/g. Method quality assurance was performed by comparing results obtained using the alternative method and the Cold Vapor Atomic Absorption Spectrometry techniques. The average results from duplicate analysis by CVAAS were 100% coincident with alternative method results. The method is applicable for screening tests and can be used in regions where a preliminary diagnosis is necessary, at programs of environmental surveillance or by scientists interested in investigating mercury geochemistry.

  4. MERCURY IN AN INSECTIVOROUS BIRD SPECIES

    EPA Science Inventory

    Mercury distributions within ecosystems must be examined to determine exposure and risk to wildlife in specific areas. In the current study, we examined exposure and uptake of mercury in nestling prothonotary warblers (protonitaria citrea) inhabiting two National Priority List (...

  5. Predicting mercury in mallard ducklings from mercury in chorioallantoic membranes

    USGS Publications Warehouse

    Heinz, G.H.; Hoffman, D.J.

    2003-01-01

    Methylmercury has been suspected as a cause of impaired reproduction in wild birds, but the confounding effects of other environmental stressors has made it difficult to determine how much mercury in the eggs of these wild species is harmful. Even when a sample egg can be collected from the nest of a wild bird and the mercury concentration in that egg compared to the laboratory-derived thresholds for reproductive impairment, additional information on the mercury levels in other eggs from that nest would be helpful in determining whether harmful levels of mercury were present in the clutch. The measurement of mercury levels in chorioallantoic membranes offers a possible way to estimate how much mercury was in a chick that hatched from an egg, and also in the whole fresh egg itself. While an embryo is developing, wastes are collected in a sac called the chorioallantoic membranes, which often remain inside the eggshell and can be collected for contaminant analysis. We fed methylmercury to captive mallards to generate a broad range of mercury levels in eggs, allowed the eggs to hatch normally, and then compared mercury concentrations in the hatchling versus the chorioallantoic membranes left behind in the eggshell. When the data from eggs laid by mercury- treated females were expressed as common logarithms, a linear equation was created by which the concentration of mercury in a duckling could be predicted from the concentration of mercury in the chorioallantoic membranes from the same egg. Therefore, if it were not possible to collect a sample egg from a clutch of wild bird eggs, the collection of the chorioallantoic membranes could be substituted, and the mercury predicted to be in the chick or whole egg could be compared to the thresholds of mercury that have been shown to cause harm in controlled feeding studies with pheasants, chickens, and mallards.

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

    PubMed

    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.

  7. Voltammetric analysis of ceftazidime after preconcentration at various mercury and carbon electrodes: application to sub-ppb level determination in urine samples.

    PubMed

    El-Maali, N A

    2000-04-28

    The electrochemical behavior of ceftazidime (CFZ) at four different kinds of electrodes viz. static mercury drop electrode (SMDE), controlled growth mercury electrode (CGME), glassy carbon electrode (GCE) and carbon paste electrode (CPE) has been presented. Optimal operational parameters have been selected for the drug preconcentration and determination in aqueous medium. Down to 2x10(-10) M CFZ is achieved as detection limit at the CGME. Modification of the CPE with polyvinyl alcohol (PVA) enhances both the sensitivity and selectivity for the drug accumulation and, therefore, its determination at very low levels. Application of the proposed method for CFZ analysis in spiked urine samples or those taken after metabolism has been easily assessed. Down to 1x10(-9) M CFZ (0.695 ng ml(-1)) could be easily achieved in such samples.

  8. Validation of a hydride generation atomic absorption spectrometry methodology for determination of mercury in fish designed for application in the Brazilian national residue control plan.

    PubMed

    Damin, Isabel C F; Santo, Maria A E; Hennigen, Rosmari; Vargas, Denise M

    2013-01-01

    In the present study, a method for the determination of mercury (Hg) in fish was validated according to ISO/IEC 17025, INMETRO (Brazil), and more recent European recommendations (Commission Decision 2007/333/EC and 2002/657/EC) for implementation in the Brazilian Residue Control Plan (NRCP) in routine applications. The parameters evaluated in the validation were investigated in detail. The results obtained for limit of detection and quantification were respectively, 2.36 and 7.88 μg kg(-1) of Hg. While the recovery varies between 90-96%. The coefficient of variation was of 4.06-8.94% for the repeatability. Furthermore, a comparison using an external proficiency testing scheme was realized. The results of method validated for the determination of the mercury in fish by Hydride generation atomic absorption spectrometry were considered suitable for implementation in routine analysis.

  9. Determination of Xanthine in the Presence of Hypoxanthine by Adsorptive Stripping Voltammetry at the Mercury Film Electrode

    PubMed Central

    Farias, Percio Augusto Mardini; Castro, Arnaldo Aguiar

    2014-01-01

    A stripping method for the determination of xanthine in the presence of hypoxanthine at the submicromolar concentration levels is described. The method is based on controlled adsorptive accumulation at the thin-film mercury electrode followed by a fast linear scan voltammetric measurement of the surface species. Optimum experimental conditions were found to be the use of 1.0 × 10−3 mol L−1 NaOH solution as supporting electrolyte, an accumulation potential of 0.00 V for xanthine and −0.50 V for hypoxanthine–copper, and a linear scan rate of 200 mV second−1. The response of xanthine is linear over the concentration ranges of 20–140 ppb. For an accumulation time of 30 minutes, the detection limit was found to be 36 ppt (2.3 × 10−10 mol L−1). Adequate conditions for measuring the xanthine in the presence of hypoxanthine, copper and other metals, uric acid, and other nitrogenated bases were also investigated. The utility of the method is demonstrated by the presence of xanthine associated with hypoxanthine, uric acid, nitrogenated bases, ATP, and ssDNA. PMID:24940040

  10. Determination of inorganic arsenic species in natural waters--benefits of separation and preconcentration on ion exchange and hybrid resins.

    PubMed

    Ben Issa, Nureddin; Rajaković-Ognjanović, Vladana N; Jovanović, Branislava M; Rajaković, Ljubinka V

    2010-07-19

    A simple method for the separation and determination of inorganic arsenic (iAs) species in natural and drinking water was developed. Procedures for sample preparation, separation of As(III) and As(V) species and preconcentration of the total iAs on fixed bed columns were defined. Two resins, a strong base anion exchange (SBAE) resin and a hybrid (HY) resin were utilized. The inductively-coupled plasma-mass spectrometry method was applied as the analytical method for the determination of the arsenic concentration in water. The governing factors for the ion exchange/sorption of arsenic on resins in a batch and a fixed bed flow system were analyzed and compared. Acidity of the water, which plays an important role in the control of the ionic or molecular forms of arsenic species, was beneficial for the separation; by adjusting the pH values to less than 8.00, the SBAE resin separated As(V) from As(III) in water by retaining As(V) and allowing As(III) to pass through. The sorption activity of the hydrated iron oxide particles integrated into the HY resin was beneficial for bonding of all iAs species over a wide range of pH values from 5.00 to 11.00. The resin capacities were calculated according to the breakthrough points in a fixed bed flow system. At pH 7.50, the SBAE resin bound more than 370 microg g(-1) of As(V) while the HY resin bound more than 4150 microg g(-1) of As(III) and more than 3500 microg g(-1) of As(V). The high capacities and selectivity of the resins were considered as advantageous for the development and application of two procedures, one for the separation and determination of As(III) (with SBAE) and the other for the preconcentration and determination of the total arsenic (with HY resin). Methods were established through basic analytical procedures (with external standards, certified reference materials and the standard addition method) and by the parallel analysis of some samples using the atomic absorption spectrometry-hydride generation

  11. Determination of Mercury Content in a Shallow Firn Core from Summit, Greenland by Isotope Dilution Inductively Coupled Plasma Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Mann, Jacqueline L.; Long, Stephen E.; Shuman, Christopher A.; Kelly, W. Robert

    2003-01-01

    The total mercury Hg content was determined in 6 cm sections of a near-surface 7 m firn core and in surrounding surface snow from Summit, Greenland (elevation: 3238 m, 72.58 N, 38.53 W) in May 2001 by isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICP-MS). The focus of this research was to evaluate the capability of the ID-CV-ICPMS technique for measuring trace levels of Hg typical of polar snow and firn. Highly enriched Hg-201 isotopic spike is added to approximately 10 ml melted core and thoroughly mixed. The Hg(+2) in the sample is reduced on line with tin (II) chloride (SnCl2) and the elemental Hg (Hg(0)) vapor pre-concentrated on to gold gauze using a commercial amalgam system. The Hg is then thermally desorbed and introduced into a quadrupole ICP-MS. The blank corrected Hg concentrations determined for all samples ranged from 0.25 ng/L to 1.74 ng/L (ppt) (average 0.59 ng/L plus or minus 0.28 ng/L) and fall within the range of those previously determined by Boutron et al., 1998 (less than or equal to 0.05 ng/L to 2.0 ng/L) for the Summit site. The average blank value was 0.19 ng/L plus or minus 0.045 ng/L (n=6). The Hg values specifically for the firn core range from 0.25 ng/L to 0.87 ng/L (average 0.51 ng/L plus or minus 0.13 ng/L) and show both values declining with time and larger variability in concentration in the top 1.8 m.

  12. Synthesis of a novel molecularly imprinted organic-inorganic hybrid polymer for the selective isolation and determination of fluoroquinolones in tilapia.

    PubMed

    Yang, Xun; Wang, Ruiling; Wang, Weihua; Yan, Hongyuan; Qiu, Mande; Song, Yanxue

    2014-01-15

    A novel molecularly imprinted organic-inorganic hybrid polymer (MI-MAA/APTS) based on a dummy molecular imprinting technique and an organic-inorganic hybrid material technique was synthesised and used as a sorbent in solid-phase extraction for the selective isolation and determination of ofloxacin (OFL), lomefloxacin (LOM), and ciprofloxacin (CIP) in tilapia samples. The MI-MAA/APTS sorbent was prepared from 3-aminopropyltriethoxysilanes (APTS) as an inorganic source and methacrylic acid (MAA) as an organic source and exhibited high mechanical strength and special affinities to the analytes. A comparison of MI-MAA/APTS with other conventional sorbents (C18 and HLB) showed that MI-MAA/APTS displayed good selectivity and affinity for OFL, LOM, and CIP, and the recoveries of the analytes at three spiked levels were in the range of 85.1-101.0%, with the relative standard deviations ≤5.1%. The presented MI-MAA/APTS-SPE-HPLC method could be potentially applied to the determination of fluoroquinolones (FQs) in complex fish samples.

  13. Solid phase extraction of mercury on sulfur loaded with N-(2-chloro benzoyl)-N'-phenylthiourea as a new adsorbent and determination by cold vapor atomic absorption spectrometry.

    PubMed

    Pourreza, N; Parham, H; Kiasat, A R; Ghanemi, K; Abdollahi, N

    2009-06-15

    This paper reports sulfur powder loaded with N-(2-chloro benzoyl)-N'-phenylthiourea as a new solid phase extractor for determination of ultra trace amounts of mercury. The mercury ions were retained on a mini-column filled with the solid phase at a flow rate of 16 mL min(-1). The retained Hg(II) ions were eluted with 3 mol L(-1) solution of HCl and measured by cold vapor atomic absorption spectrometry (CV-AAS). The mercury vapors were generated by a homemade Reaction Cell-Gas Liquid Separator (RC-GLS). The effect of different variables such as pH, sample flow rate, amounts of ligand loaded on sulfur and SnCl2 concentration was investigated. Calibration curve was linear in the range of 0.02-1.20 microg L(-1) with r=0.9991 (n=8). The limit of detection (LOD) based on three times the standard deviation of the blank was 0.012 and 0.003 microg L(-1) when 250 and 1000 mL sample volumes were used, respectively. The relative standard deviation (R.S.D.) for determination of 0.04 and 1.00 microg L(-1) of Hg(II) was 3.9 and 1.2% (n=8), respectively. The method was successfully applied to determine Hg(II) in water and marine samples.

  14. Simultaneous preconcentration of copper and mercury in water samples by cloud point extraction and their determination by inductively coupled plasma atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Shoaee, Hamta; Roshdi, Mina; Khanlarzadeh, Nasibeh; Beiraghi, Asadollah

    2012-12-01

    A cloud-point extraction process coupled to ICP-OES by using 3-nitro benzaldehyde thiosemicarbazone (3-NBT) as complexing agent was developed for the simultaneous preconcentration and determination of copper and mercury in water samples. The variables affecting the complexation and extraction steps were optimized. Under the optimum conditions (i.e. 1.5 × 10-5 mol L-1 ligand, 0.3% (v/v) Triton X-114, 55 °C equilibrium temperature, incubation time of 30 min) the calibration graphs were linear in the range of 5-120 and 10-100 ng mL-1 with enhancement factor of 82.7 and 51.3 for Cu2+ and Hg2+, respectively. The preconcentration factors were 28.6 in both cases and detection limits were obtained 0.48 for Cu and 1.1 ng mL-1 for Hg. The precisions (R.S.D.%) for five replicate determinations at 50 ng mL-1 of copper and mercury were better than 1.8% and 3.2%, respectively. The accuracy of the proposed method is validated by analyzing a certified reference material of water (RTC-QCI-049) with satisfactory results. Finally, the proposed method was utilized successfully for the determination of copper and mercury in surface water (river), tap water and bottled mineral water samples.

  15. Mercury in the national parks

    USGS Publications Warehouse

    Pritz, Colleen Flanagan; Eagles-Smith, Collin; Krabbenhoft, David

    2014-01-01

    One thing is certain: Even for trained researchers, predicting mercury’s behavior in the environment is challenging. Fundamentally it is one of 98 naturally occurring elements, with natural sources, such as volcanoes, and concentrated ore deposits, such as cinnabar. Yet there are also human-caused sources, such as emissions from both coal-burning power plants and mining operations for gold and silver. There are elemental forms, inorganic or organic forms, reactive and unreactive species. Mercury is emitted, then deposited, then re-emitted—thus earning its mercurial reputation. Most importantly, however, it is ultimately transferred into food chains through processes fueled by tiny microscopic creatures: bacteria.

  16. Mercury speciation and selenium in toothed-whale muscles.

    PubMed

    Sakamoto, Mineshi; Itai, Takaaki; Yasutake, Akira; Iwasaki, Toshihide; Yasunaga, Genta; Fujise, Yoshihiro; Nakamura, Masaaki; Murata, Katsuyuki; Chan, Hing Man; Domingo, José L; Marumoto, Masumi

    2015-11-01

    Mercury accumulates at high levels in marine mammal tissues. However, its speciation is poorly understood. The main goal of this investigation was to establish the relationships among mercury species and selenium (Se) concentrations in toothed-whale muscles at different mercury levels. The concentrations of total mercury (T-Hg), methylmercury (MeHg), inorganic mercury (I-Hg) and Se were determined in the muscles of four toothed-whale species: bottlenose dolphins (n=31), Risso's dolphins (n=30), striped dolphins (n=29), and short-finned pilot whales (n=30). In each species, the MeHg concentration increased with increasing T-Hg concentration, tending to reach a plateau. In contrast, the proportion of MeHg in T-Hg decreased from 90-100% to 20-40%. The levels of T-Hg and Se showed strong positive correlations. Se/I-Hg molar ratios rapidly decreased with the increase of I-Hg and reached almost 1 in all species. These results suggested that the demethylated MeHg immediately formed Se/I-Hg equimolar complex of mercury selenide (HgSe) in their muscles. In addition, an X-ray absorption fine structure analysis (XAFS) of a bottlenose dolphin muscle confirmed that the dominant chemical form of the Se/I-Hg equimolar complex was HgSe. HgSe was mainly localized in cells near the endomysium using electron probe microanalysis (EPMA). These results suggested that the demethylated MeHg finally deposits within muscle cells of bottlenose dolphin as an inert HgSe.

  17. Role of Dispersive Interactions in Determining Structural Properties of Organic-Inorganic Halide Perovskites: Insights from First-Principles Calculations.

    PubMed

    Egger, David A; Kronik, Leeor

    2014-08-07

    A microscopic picture of structure and bonding in organic-inorganic perovskites is imperative to understanding their remarkable semiconducting and photovoltaic properties. On the basis of a density functional theory treatment that includes both spin-orbit coupling and dispersive interactions, we provide detailed insight into the crystal binding of lead-halide perovskites and quantify the effect of different types of interactions on the structural properties. Our analysis reveals that cohesion in these materials is characterized by a variety of interactions that includes important contributions from both van der Waals interactions among the halide atoms and hydrogen bonding. We also assess the role of spin-orbit coupling and show that it causes slight changes in lead-halide bonding that do not significantly affect the lattice parameters. Our results establish that consideration of dispersive effects is essential for understanding the structure and bonding in organic-inorganic perovskites in general and for providing reliable theoretical predictions of structural parameters in particular.

  18. Fate of mercury in flue gas desulfurization gypsum determined by Temperature Programmed Decomposition and Sequential Chemical Extraction.

    PubMed

    Zhu, Zhenwu; Zhuo, Yuqun; Fan, Yaming; Wang, Zhipeng

    2016-05-01

    A considerable amount of Hg is retained in flue gas desulfurization (FGD) gypsum from Wet Flue Gas Desulfurization (WFGD) systems. For this reason, it is important to determine the species of Hg in FGD gypsum not only to understand the mechanism of Hg removal by WFGD systems but also to determine the final fate of Hg when FGD gypsum is disposed. In this study, Temperature Programmed Decomposition (TPD) and Sequential Chemical Extraction (SCE) were applied to FGD gypsum to identify the Hg species in it. The FGD gypsum samples were collected from seven coal-fired power plants in China, with Hg concentrations ranging from 0.19 to 3.27μg/g. A series of pure Hg compounds were used as reference materials in TPD experiments and the results revealed that the decomposition temperatures of different Hg compounds increase in the order of Hg2Cl2mercury sulfides were the primary compounds. The results of SCE indicated that Hg was mainly distributed in the strongly complexed phase. The low Hg content in FGD gypsum increases the ambiguity of assigning extraction fractions to certain Hg species by SCE. The fact that the primary compounds in FGD gypsum are HgS phases leads the leaching of Hg in the natural environment to be quite low, but a considerable amount of Hg may be released during the industrial heating process.

  19. Capillary electrophoretic method for the determination of inorganic and organic anions in real samples. Strategies for improving repeatability and reproducibility.

    PubMed

    Blanco-Heras, Gustavo A; Turnes-Carou, M Isabel; López-Mahía, Purificación; Muniategui-Lorenzo, Soledad; Prada-Rodríguez, Darío; Fernández-Fernández, Esther

    2007-03-16

    Selectivity and robustness of the pyromellitic acid (PMA) based background electrolyte was improved in order to increase its applicability for routine analysis of inorganic and organic anions in real samples. An electrolyte composed of 6.75 mM PMA, 0.5 mM hexamethonium hydroxide as electroosmotic flow (EOF) modifier, Ca(2+) 0.05 mM as complexation agent and pH adjusted to 7.6 with TEA 1M allows for the separation of 22 inorganic and organic anions in less than 17 min. Good RSDs for within-day migration time reproducibility (0.03-0.9%) and day-to-day analyses (0.04-1.4%) were obtained by the use of two internal standards, allowing for an accurate compound identification. The detection limits ranged from 0.1 to 0.4 mgL(-1) (S/N=3) for hydrodynamic injection (1250 mbars). The applicability of the proposed method was demonstrated by the analysis of inorganic and organic anions in diverse real samples. The recoveries obtained ranged from 93 to 106%.

  20. Electrochemically deposited gold nanoparticles on a carbon paste electrode surface for the determination of mercury.

    PubMed

    Sahoo, Srikant; Satpati, Ashis Kumar; Reddy, Annareddy Venkata Ramana

    2015-01-01

    An electrochemical method was developed for the determination of Hg at ultratrace levels using an Au nanoparticle (AuNP) array modified carbon paste electrode (CPE) by anodic stripping voltammetry. Scanning electron microscopy measurements imaged the size and shape of AuNPs on the CPE substrate; it was possible to tune the size and the NP density by changing the deposition time and medium. Electrochemical characterization of the AuNP modified CPE was carried out using cyclic voltammetry and electrochemical impedance measurements. Interferences due to some commonly occurring metal ions and surfactants on the stripping peak of Hg were also investigated. The 3σ detection limit for Hg using the AuNP modified electrode was as 0.24 μg/L. This method was applied to determine Hg in soil samples.

  1. Mercury Exposure and Heart Diseases

    PubMed Central

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

    2017-01-01

    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. PMID:28085104

  2. Identification and distribution of mercury species in rat tissues following administration of thimerosal or methylmercury.

    PubMed

    Rodrigues, Jairo L; Serpeloni, Juliana M; Batista, Bruno L; Souza, Samuel S; Barbosa, Fernando

    2010-11-01

    Methylmercury (Met-Hg) is one the most toxic forms of Hg, with a considerable range of harmful effects on humans. Sodium ethyl mercury thiosalicylate, thimerosal (TM) is an ethylmercury (Et-Hg)-containing preservative that has been used in manufacturing vaccines in many countries. Whereas the behavior of Met-Hg in humans is relatively well known, that of ethylmercury (Et-Hg) is poorly understood. The present study describes the distribution of mercury as (-methyl, -ethyl and inorganic mercury) in rat tissues (brain, heart, kidney and liver) and blood following administration of TM or Met-Hg. Animals received one dose/day of Met-Hg or TM by gavage (0.5 mg Hg/kg). Blood samples were collected after 6, 12, 24, 48, 96 and 120 h of exposure. After 5 days, the animals were killed, and their tissues were collected. Total blood mercury (THg) levels were determined by ICP-MS, and methylmercury (Met-Hg), ethylmercury (Et-Hg) and inorganic mercury (Ino-Hg) levels were determined by speciation analysis with LC-ICP-MS. Mercury remains longer in the blood of rats treated with Met-Hg compared to that of TM-exposed rats. Moreover, after 48 h of the TM treatment, most of the Hg found in blood was inorganic. Of the total mercury found in the brain after TM exposure, 63% was in the form of Ino-Hg, with 13.5% as Et-Hg and 23.7% as Met-Hg. In general, mercury in tissues and blood following TM treatment was predominantly found as Ino-Hg, but a considerable amount of Et-Hg was also found in the liver and brain. Taken together, our data demonstrated that the toxicokinetics of TM is completely different from that of Met-Hg. Thus, Met-Hg is not an appropriate reference for assessing the risk from exposure to TM-derived Hg. It also adds new data for further studies in the evaluation of TM toxicity.

  3. Simple method of determination of copper, mercury and lead in potable water with preliminary pre-concentration by total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Hołyńska, B.; Ostachowicz, B.; Wȩgrzynek, D.

    1996-06-01

    Total reflection X-ray fluorescence spectrometry and chemical pre-concentration procedures have been applied for the analysis of trace concentrations of copper, mercury, and lead in drinking water samples. A simple total reflection module has been used in X-ray measurements. The elements under investigation were pre-concentrated by complexation using a mixture of carbamates followed by solvent extraction with methyl isobutyl ketone. The preconcentration procedure was tested with the use of twice-distilled water samples and samples of mineral and tap water spiked with known additions of copper, mercury, and lead. The obtained recovery and precision values are presented. The minimum detection limits for the determination of these elements in mineral and tap water samples were found to be 40 ng l -1, 60 ng l -1, and 60 ng l -1, respectively.

  4. THE EFFECT OF MERCURY CONTROLS ON WALLBOARD MANUFACTURE

    SciTech Connect

    Sandra Meischen

    2004-07-01

    Pending EPA regulations may mandate 70 to 90% mercury removal efficiency from utility flue gas. A mercury control option is the trapping of oxidized mercury in wet flue gas desulfurization systems (FGD). The potential doubling of mercury in the FGD material and its effect on mercury volatility at temperatures common to wallboard manufacture is a concern that could limit the growing byproduct use of FGD material. Prediction of mercury fate is limited by lack of information on the mercury form in the FGD material. The parts per billion mercury concentrations prevent the identification of mercury compounds by common analytical methods. A sensitive analytical method, cold vapor atomic fluorescence, coupled with leaching and thermodecomposition methods were evaluated for their potential to identify mercury compounds in FGD material. The results of the study suggest that the mercury form is dominated by the calcium sulfate matrix and is probably associated with the sulfate form in the FGD material. Additionally, to determine the effect of high mercury concentration FGD material on wallboard manufacture, a laboratory FGD unit was built to trap the oxidized mercury generated in a simulated flue gas. Although the laboratory prepared FGD material did not contain the mercury concentrations anticipated, further thermal tests determined that mercury begins to evolve from FGD material at 380 to 390 F, consequently dropping the drying temperature should mitigate mercury evolution if necessary. Mercury evolution is also diminished as the weight of the wallboard sample increased. Consequently, mercury evolution may not be a significant problem in wallboard manufacture.

  5. PATHOLOGICAL EFFECTS OF DIETARY METHYL MERCURY IN AMERICAN KESTRELS (FALCO SPARVERIIUS)

    EPA Science Inventory

    Methyl mercury in the aquatic food web poses significant health risks to both wildlife and humans. One primary source of mercury contamination for both the aquatic and terrestrial systems is atmospheric deposition of inorganic mercury from industrial emissions. Once in the enviro...

  6. GASEOUS ELEMENTAL MERCURY IN THE MARINE BOUNDARY LAYER: EVIDENCE FOR RAPID REMOVAL IN ANTHROPOGENIC POLLUTION

    EPA Science Inventory

    In this study, gas-phase elemental mercury (Hg0) and related species (including inorganic reactive gaseous mercury (RGM) and particulate mercury (PHg)) were measured at Cheeka Peak Observatory (CPO), Washington State, in the marine boundary layer (MBL) during 2001-2002. Air of...

  7. Determination of mercury in sewage sludge by direct slurry sampling graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Baralkiewicz, Danuta; Gramowska, Hanka; Kózka, Małgorzata; Kanecka, Anetta

    2005-03-01

    Ultrasonic slurry sampling electrothermal atomic absorption spectrometry (ETAAS) method was elaborated to the determination of Hg in sewage sludge samples with the use of KMnO 4+Pd modifier. The minimum sample amount required for slurry preparation with respect to sample homogeneity was evaluated by weighting masses between 3 and 30 mg directly into the autosampler cups. Validation of the proposed method was performed with the use of Certified Reference Materials of sewage sludge, CRM 007-040 and CRM 144R. Two sewage sludge samples from Poznañ (Poland) city were analysed using the present direct method and a method with sample digestion, resulting in no difference within statistical error.

  8. Mercury determination in urine samples by gold nanostructured screen-printed carbon electrodes after vortex-assisted ionic liquid dispersive liquid-liquid microextraction.

    PubMed

    Fernández, Elena; Vidal, Lorena; Costa-García, Agustín; Canals, Antonio

    2016-04-07

    A novel approach is presented to determine mercury in urine samples, employing vortex-assisted ionic liquid dispersive liquid-liquid microextraction and microvolume back-extraction to prepare samples, and screen-printed electrodes modified with gold nanoparticles for voltammetric analysis. Mercury was extracted directly from non-digested urine samples in a water-immiscible ionic liquid, being back-extracted into an acidic aqueous solution. Subsequently, it was determined using gold nanoparticle-modified screen-printed electrodes. Under optimized microextraction conditions, standard addition calibration was applied to urine samples containing 5, 10 and 15 μg L(-1) of mercury. Standard addition calibration curves using standards between 0 and 20 μg L(-1) gave a high level of linearity with correlation coefficients ranging from 0.990 to 0.999 (N = 5). The limit of detection was empirical and statistically evaluated, obtaining values that ranged from 0.5 to 1.5 μg L(-1), and from 1.1 to 1.3 μg L(-1), respectively, which are significantly lower than the threshold level established by the World Health Organization for normal mercury content in urine (i.e., 10-20 μg L(-1)). A certified reference material (REC-8848/Level II) was analyzed to assess method accuracy finding 87% and 3 μg L(-1) as the recovery (trueness) and standard deviation values, respectively. Finally, the method was used to analyze spiked urine samples, obtaining good agreement between spiked and found concentrations (recovery ranged from 97 to 100%).

  9. Total mercury levels in hair, toenail, and urine among women free from occupational exposure and their relations to renal tubular function

    SciTech Connect

    Ohno, Tomoko; Sakamoto, Mineshi; Kurosawa, Tomoko; Dakeishi, Miwako; Iwata, Toyoto; Murata, Katsuyuki . E-mail: winestem@med.akita-u.ac.jp

    2007-02-15

    To investigate the relations among total mercury levels in hair, toenail, and urine, together with potential effects of methylmercury intake on renal tubular function, we determined their levels, and urinary N-acetyl-{beta}-d-glucosaminidase activity (NAG) and {alpha}{sub 1}-microglobulin (AMG) in 59 women free from occupational exposures, and estimated daily mercury intakes from fish and other seafood using a food frequency questionnaire. Mercury levels (mean+/-SD) in the women were 1.51+/-0.91{mu}g/g in hair, 0.59+/-0.32{mu}g/g in toenail, and 0.86+/-0.66{mu}g/g creatinine in urine; and, there were positive correlations among them (P<0.001). The daily mercury intake of 9.15+/-7.84{mu}g/day was significantly correlated with total mercury levels in hair, toenail, and urine (r=0.551, 0.537, and 0.604, P<0.001). Among the women, the NAG and AMG were positively correlated with both the daily mercury intake and mercury levels in hair, toenail, and urine (P<0.01); and, these relations were almost similar when using multiple regression analysis to adjust for possible confounders such as urinary cadmium (0.47+/-0.28{mu}g/g creatinine) and smoking status. In conclusion, mercury resulting from fish consumption can explain total mercury levels in hair, toenail, and urine to some degree (about 30%), partly through the degradation into the inorganic form, and it may confound the renal tubular effect of other nephrotoxic agents. Also, the following equation may be applicable to the population neither with dental amalgam fillings nor with occupational exposures: [hair mercury ({mu}g/g)]=2.44x[toenail mercury ({mu}g/g)].

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

    SciTech Connect

    Jain, V.; Shah, H.; Bannochie, C. J.; Wilmarth, W. R.

    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

  11. Mercury volatilization by R factor systems in Escherichia coli isolated from aquatic environments of India.

    PubMed

    Gupta, Neerja; Ali, Arif

    2004-02-01

    Ten Escherichia coli strains isolated from five different aquatic environments representing three distinct geographical regions of India showed significantly high levels of tolerance to the inorganic form of mercury, i.e., mercuric chloride (HgCl(2)). MRD14 isolated from the Dal Lake (Kashmir) could tolerate the highest concentration of HgCl(2), i.e., 55 microg/mL, and MRF1 from the flood water of the Yamuna River (Delhi) tolerated the lowest concentration, i.e., 25 microg/mL. All ten strains revealed the presence of a plasmid of approximately 24 kb, and transformation of the isolated plasmids into the mercury-sensitive competent cells of E. coli DH5alpha rendered the transformants resistant to the same concentration of mercury as the wild-type strains. Mating experiments were performed to assess the self-transmissible nature of these promiscuous plasmids. The transfer of mercury resistance from these wild-type strains to the mercury-sensitive, naladixic acid-resistant E. coli K12 (F(-) lac(+)) strain used as a recipient was observed in six of the nine strains tested. Transconjugants revealed the presence of a plasmid of approximately 24 kb. An evaluation of the mechanism of mercury resistance in the three most efficient strains (MRG12, MRD11, and MRD14) encountered in our study was determined by cold vapor atomic absorption spectroscopy (CV-AAS), and it was noted that resistance to HgCl(2) was conferred by conversion of the toxic ionic form of mercury (Hg(++)) to the nontoxic elemental form (Hg(0)) in all three strains. MRD14 volatilized mercury most efficiently.

  12. Determination of total mercury for marine environmental monitoring studies by solid sampling continuum source high resolution atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Mandjukov, Petko; Orani, Anna Maria; Han, Eunmi; Vassileva, Emilia

    2015-01-01

    The most critical step in almost all commonly used analytical procedures for Hg determination is the sample preparation due to its extreme volatility. One of the possible solutions of this problem is the application of methods for direct analysis of solid samples. The possibilities for solid sampling high resolution continuum source atomic absorption spectrometry (HR CS AAS) determination of total mercury in various marine environmental samples e.g. sediments and biota are object of the present study. The instrumental parameters were optimized in order to obtain reproducible and interference free analytical signal. A calibration technique based on the use of solid standard certified reference materials similar to the nature of the analyzed sample was developed and applied to various CRMs and real samples. This technique allows simple and reliable evaluation of the uncertainty of the result and the metrological characteristics of the method. A validation approach in line with the requirements of ISO 17025 standard and Eurachem guidelines was followed. With this in mind, selectivity, working range (0.06 to 25 ng for biota and 0.025 to 4 ng for sediment samples, expressed as total Hg) linearity (confirmed by Student's t-test), bias (1.6-4.3%), repeatability (4-9%), reproducibility (9-11%), and absolute limit of detection (0.025 ng for sediment, 0.096 ng for marine biota) were systematically assessed using solid CRMs. The relative expanded uncertainty was estimated at 15% for sediment sample and 8.5% for marine biota sample (k = 2). Demonstration of traceability of measurement results is also presented. The potential of the proposed analytical procedure, based on solid sampling HR CS AAS technique was demonstrated by direct analysis of sea sediments form the Caribbean region and various CRMs. Overall, the use of solid sampling HR CS AAS permits obtaining significant advantages for the determination of this complex analyte in marine samples, such as straightforward

  13. Arsenic, inorganic

    Integrated Risk Information System (IRIS)

    Arsenic , inorganic ; CASRN 7440 - 38 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  14. To Mercury dynamics

    NASA Astrophysics Data System (ADS)

    Barkin, Yu. V.; Ferrandiz, J. M.

    frequencies of free oscillations of core-mantle system of Mercury. Based on the mentioned data about Mercury (Barkin, 1976) we have been obtained the following model values of moments of inertia of the Mercury and for its core:A=0.3499534, B=0.3499667, C=0.35; A_c =B_c =0.1749767, C_c =0.175000 (1quad unit=mR^2, m and R is a mass and a mean radius of the Mercury). Here we used model values for moments of inertia of the core using also some analogy with axysimmetrical model of the core of the Moon from paper Williams et al. (2003). Corresponding periods of free oscillations were determined on the base specially constructed equations of developed theory. They are equal: T_1 =260543\\cdot Trot years and T_2 =0.999468\\cdot Trot (Trot =58.6462 days is a period of Mercury rotation). Last period determines long period of relative oscillation of the core and mantleT_r . The mentioned periods are equal: T_1 =713years and T_r =302years. Barkin's work was accepted by grant SAB2000-0235 of Ministry of Education of Spain and partially by grants AYA2001-0787 and ESP2001-4533 is also aknowledged. References Anderson J.D., Colombo G., Esposito P.B., Lau E.L., Trager G.B.: 1987. The mass, gravity field and ephemeris of Mercury. Icarus, pp. 337-349. Anselmi A., Scoon G.E.N.: 2001. BepiColombo, ESA's Mercury Cornerstone mission. Planetary and Space Science, 49, pp. 1409-1420. Barkin Yu.V.: 1976. About plane periodic motions of a rigid body in gravitational field of a sphere. Astron. J., v. 53, pp. 1110-1119. In Russian. Barkin Yu.V.: 1987. An analytical theory of the lunar rotational motion. Proc. Int. Symp. ``Figure and Dynamics of Earth, Moon and Planets'' (September 1986, Prague). Monograph series of VUGTK. Prague. Pp. 657-677. Beletskij V.V.: 1972. Resonance rotation of celestial bodies and Cassini's laws. Celestial Mechanics, v.6, N3, pp. 356-378. Colombo G.: 1966. Cassini's second and third laws, Astron. J., 71, p. 891. Esposito P.B., Anderson J.D., Ng A.T.Y.: 1977. Experimental

  15. Effect of salinity on methylation of mercury

    SciTech Connect

    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.

  16. Comparative study of inorganic elements determined in whole blood from Dmd(mdx)/J mice strain by EDXRF and NAA analytical techniques.

    PubMed

    Redígolo, M M; Sato, I M; Metairon, S; Zamboni, C B

    2016-04-01

    Several diseases can be diagnosed observing the variation of specific elements concentration in body fluids. In this study the concentration of inorganic elements in blood samples of dystrophic (Dmd(mdx)/J) and C57BL/6J (control group) mice strain were determined. The results obtained from Energy Dispersive X-ray Fluorescence (EDXRF) were compared with Neutron Activation Analysis (NAA) technique. Both analytical techniques showed to be appropriate and complementary offering a new contribution for veterinary medicine as well as detailed knowledge of this pathology.

  17. Determination of mercury(II) in aquatic plants using quinoline-thiourea conjugates as a fluorescent probe.

    PubMed

    Feng, Guodong; Ding, Yuanyuan; Gong, Zhiyong; Dai, Yanna; Fei, Qiang

    2013-01-01

    In this study, a quinoline-thiourea conjugate (1-phenyl-3-(quinoline-8-yl) thiourea, PQT) was synthesized and used as a fluorescence sensor to detect mercury ion. The observation is coincident with the well-documented phenomenon that a thiocarbonyl-containing group on a fluorochrome quenches the fluorescence due to the heavy atom effect of the S atom. The large fluorescence enhancement of PQT in the buffered MeCN-water mixture (1/1 v/v; HEPES 100 mM; pH 8.0) was caused by the Hg(2+) induced transformation of the thiourea function into a urea group. As such, protic solvents can be ascribed to hydrogen bond formation on the carbonyl oxygen to reduce the internal conversion rate. The fluorescence intensity of PQT was enhanced quantitatively with an increase in the concentration of mercury ion. The limit of detection of Hg(2+) was 7.5 nM. The coexistence of other metal ions with mercury had no obvious influence on the detection of mercury. A quinolone-thiourea conjugate was used as a fluorescent probe to detect Hg(2+) in aquatic plants and the experimental results were satisfactory.

  18. An evaluation of analytical techniques for determination of lead, cadmium, chromium, and mercury in food-packaging materials.

    PubMed

    Perring, L; Alonso, M I; Andrey, D; Bourqui, B; Zbinden, P

    2001-05-01

    Closed microwave digestion and a high-pressure asher have been evaluated for wet-oxidation and extraction of lead, cadmium, chromium, and mercury from a range of typical packaging materials used for food products. For the high-pressure asher a combination of nitric and sulfuric acids was efficient for destruction of a range of packaging materials; for polystyrene, however, nitric acid alone was more efficient. For microwave digestion, a reagent containing nitric acid, sulfuric acid, and hydrogen peroxide was used for all materials except polystyrene. Use of the high-pressure asher resulted in the highest recoveries of spiked lead (median 92%), cadmium (median 92%), chromium (median 97%), and mercury (median 83%). All samples were spiked before digestion with 40 microg L(-1) Cd, Cr, and Pb and 8 microg L(-1) Hg in solution. The use of indium as internal standard improved the accuracy of results from both ICP-MS and ICP-AES. Average recovery of the four elements from spiked packaging materials was 92 +/- 14% by ICP-MS and 87 +/- 15% (except for mercury) by ICP-AES. For mercury analysis by CVAAS, use of tin(II) chloride as reducing agent resulted in considerably better accuracy than use of sodium borohydride reagent.

  19. DEVELOPMENT OF AN ECOLOGICAL RISK ASSESSMENT METHODOLOGY FOR ASSESSING WILDLIFE EXPOSURE RISK ASSOCIATED WITH MERCURY-CONTAMINATED SEDIMENTS IN LAKE AND RIVER SYSTEMS

    EPA Science Inventory

    Mercury is an important environmental contaminant with a complex chemistry cycle. The form of mercury entering an ecosystem from anthropogenic and natural sources is generally inorganic, while the environmentally relevant form is in the organic form, methylmercury. Therefore, the...

  20. Amperometric determination of cadmium, lead, and mercury metal ions using a novel polymer immobilised horseradish peroxidase biosensor system.

    PubMed

    Silwana, Bongiwe; Van Der Horst, Charlton; Iwuoha, Emmanuel; Somerset, Vernon

    2014-01-01

    This work was undertaken to develop a novel Pt/PANI-co-PDTDA/HRP biosensor system for environmental applications to investigate the inhibition studies by specific heavy metals, to provide data suitable for kinetic studies and further application of the biosensor to environmental samples. The newly constructed biosensor was compared to the data of the well-researched Pt/PANI/HRP biosensor. Optimised experimental conditions, such as the working pH for the biosensor was evaluated. The functionality of the amperometric enzyme sensor system was demonstrated by measuring the oxidation current of hydrogen peroxide followed by the development of an assay for determination of metal concentration in the presence of selected metal ions of Cd(2+), Pb(2+) and Hg(2+). The detection limits were found to be 8 × 10(-4) μg L(-1) for cadmium, 9.38 × 10(-4) μg L(-1) for lead and 7.89 × 10(-4) μg L(-1) for mercury. The World Health Organisation recommended that the maximum safety level of these metals should not exceed 0.005 mg L(-1) of Cd(2+), 0.01 mg L(-1) of Pb(2+) and 0.001 mg L(-1) of Hg(2+.), respectively. The analytical and detection data for the metals investigated were observed to be lower than concentrations recommended by several bodies including World Health Organisation and Environmental Protection Agencies. Therefore the biosensors developed in this study can be used to screen the presence of these metals in water samples because of its low detection limit. The modes of inhibition of horseradish peroxidase by Pb(2+), Cd(2+) and Hg(2+) as analysed using the double reciprocal plots of the Michaelis-Menten equation was found to be reversible and uncompetitive inhibition. Based on the Km(app) and Imax values for both biosensors the results have shown smaller values. These results also proved that the enzyme modified electrode is valuable and can be deployed for the determination or screening of heavy metals.

  1. The Planet Mercury Surface Spectroscopy and Analysis from the Kuiper Airborne Observatory and Analysis and Modeling to Determine Surface Composition

    NASA Technical Reports Server (NTRS)

    Sprague, Ann

    1997-01-01

    We had two successful flights to observe Mercury from the Kuiper Airborne Observatory (KAO) using High-efficiency Infrared Faint-Object Grating Spectrograph (HIFOGS). Flights were May 8, 1995 (eastern elongation) and July 6, 1995 (western elongation) For the observations one half of the primary mirror was covered to prevent sunlight from entering the telescope. All equipment and the airplane and its crew performed well. These flights were historical firsts for the KAO and for spectroscopy of Mercury in that it was the first time any spectroscopic observations of Mercury from above the Earth's atmosphere had been made. It was the first time the KAO had been used to @bserve an object less than 30 degrees from the Sun. Upon completion of the basic data reduction it became obvious that extensive modeling and analysis would be required to understand the data. It took three years of a graduate student's time and part time the PI to do the thermal modeling and the spectroscopic analysis. This resulted in a lengthy publication. A copy of this publication is attached and has all the data obtained in both KAO flights and the results clearly presented. Notable results are: (1) The observations found an as yet unexplained 5 micron emission enhancement that we think may be a real characteristic of Mercury's surface but could have an instrumental cause; (2) Ground-based measurements or an emission maximum at 7.7 microns were corroborated. The chemical composition of Mercury's surface must be feldspathic in order to explain spectra features found in the data obtained during the KAO flights.

  2. Synthesis of mercury cuprates

    NASA Astrophysics Data System (ADS)

    Odier, P.; Sin, A.; Toulemonde, P.; Bailly, A.; LeFloch, S.

    2000-08-01

    Mercury cuprates have very interesting potential applications that have not been thoroughly explored until now because of the complexity of their synthesis. This paper presents an overview of recent results concerning their processing. At first, a simple sol-gel technique is described that permits one to easily and intimately mix the precursors. The method uses the gelification of an inorganic solution of the cations by acrylamide polymerization. Mercuration of the precursor at moderate pressures (<2-5 MPa) is then discussed. The control of the total pressure during the synthesis by a simple method is shown, and this enables one to quantify some important parameters of the synthesis and to optimize the superconducting properties. This method has been also used successfully to incorporate mercury into layers of precursors and then to form thick layers of superconducting (Hg, Re)-1223, c-axis oriented. Finally, mercuration at higher pressures (up to 6 GPa) is considered and the case of the double mercury layer Hg-2212 is discussed in connection with the oxygen content of the reactants.

  3. Watershed Management and Mercury Biogeochemical Cycling in Lake Zapotlan, Mexico

    NASA Astrophysics Data System (ADS)

    Malczyk, E. A.; Branfireun, B. A.

    2009-05-01

    Lake Zapotlan is an endorheic subtropical eutrophic lake located in Jalisco State, Mexico. The lake supports a small but important local fishery for carp (Cyprinus sp.) and tilapia (Oreochromis sp.) and is an internationally recognized RAMSAR site. Very little research exists in these regions regarding mercury biogeochemical cycling. The lake receives considerable untreated municipal wastewater discharge that is elevated in inorganic total mercury (250-800 ng Hg/L) and organic methylmercury (3-10 ng CH3Hg+/L). The lake is also located on an active fault zone near an active volcano which may cause natural mercury enrichment. To assess a mercury risk to the commercial fishery we investigated the distribution of total inorganic mercury and organic methylmercury in waters, sediments, and fish tissues of the lake, surrounding wetlands, and incoming waters. Although there were high concentrations of inorganic mercury entering the lake in wastewater and seasonal tributary stream flow inputs, average concentrations in lake surface waters (3 ng Hg/L) and sediments (50 ng Hg/gdw) were relatively low. Average concentrations of total inorganic mercury were an order of magnitude higher in water (70 ng Hg/L) and sediment (245 ng Hg/gdw) in wetlands receiving the wastewater discharges. Mercury loading to the main body of the lake is likely reduced by these wetland buffer zones which allow mercury bound to particulate matter to settle out. A similar pattern was seen with respect to methylmercury concentrations. Average concentrations of methylmercury in lake surface water (below detect) and sediment (0.1 ng/gdw) were lower than in impounded wetlands (1 ng CH3Hg+/L, 0.7 ng CH3Hg+/gdw). Mercury concentrations in tilapia (3.5 ng/g) and carp (8 ng/g) from the commercial catch were found to be low in mercury; likely due to a combination of physiological, biogeochemical, and ecological factors.

  4. Preservation of samples for dissolved mercury

    USGS Publications Warehouse

    Hamlin, S.N.

    1989-01-01

    Water samples for dissolved mercury requires special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a large variety of concentrations and dissolved forms. Because this acid-oxidant preservative acts as a sink for airborne mercury and plastic containers are permeable to mercury vapor, glass bottles are preferred for sample collection. To maintain a healthy work environment and minimize the potential for contamination of water samples, mercury and its compounds are isolated from the atmosphere while in storage. Concurrently, a program to monitor environmental levels of mercury vapor in areas of potential contamination is needed to define the extent of mercury contamination and to assess the effectiveness of mercury clean-up procedures.Water samples for dissolved mercury require special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a

  5. A molecularly imprinted organic-inorganic hybrid monolithic column for the selective extraction and HPLC determination of isoprocarb residues in rice.

    PubMed

    Yang, Ting; Ma, Chao; Chen, Huaixia; Zhang, Yajie; Dang, Xueping; Huang, Jianlin

    2014-03-01

    An IPC-imprinted (IPC is isoprocarb) poly(methacrylic acid)/SiO2 hybrid monolithic column was prepared and applied for the recognition of the template. The hybrid monolithic column was synthesized in a micropipette tip using methyltrimethoxysilane as the inorganic precursor, 3-(methacryloxy)propyltrimethoxysilane as the coupling agent, and ethylene glycol dimethacrylate as the cross-linker. The synthesis conditions, including the porogenic solvent, coupling agent, volume ratio of the inorganic alcoholysate and organic part, were optimized. The prepared monolithic column was characterized by SEM and FTIR spectroscopy. A simple, rapid, and sensitive method for the determination of IPC in rice using the imprinted monolithic column microextraction combined with HPLC was developed. Several parameters affecting the sample pretreatment were investigated, including the eluent, washing solution, and loading sample volume. The linearity of the calibration curve was observed in the range of 9.0-1000 μg/kg for IPC in rice with the correlation coefficient (r2) of 0.9983. The LOD was 3.0 μg/kg (S/N = 3). The assay gave recovery values ranging from 91 to 107%. The proposed method has been successfully applied for the selective extraction and sensitive determination of IPC in rice and a satisfactory result was obtained.

  6. Mercury speciation by high-performance liquid chromatography atomic fluorescence spectrometry using an integrated microwave/UV interface. Optimization of a single step procedure for the simultaneous photo-oxidation of mercury species and photo-generation of Hg0

    NASA Astrophysics Data System (ADS)

    de Quadros, Daiane P. C.; Campanella, Beatrice; Onor, Massimo; Bramanti, Emilia; Borges, Daniel L. G.; D'Ulivo, Alessandro

    2014-11-01

    We described the hyphenation of photo-induced chemical vapor generation with high performance liquid chromatography-atomic fluorescence spectrometry (HPLC-AFS) for the quantification of inorganic mercury, methylmercury (MeHg) and ethylmercury (EtHg). In the developed procedure, formic acid in mobile phase was used for the photodecomposition of organomercury compounds and reduction of Hg2 + to mercury vapor under microwave/ultraviolet (MW/UV) irradiation. We optimized the proposed method studying the influence of several operating parameters, including the type of organic acid and its concentration, MW power, composition of HPLC mobile phase and catalytic action of TiO2 nanoparticles. Under the optimized conditions, the limits of detection were 0.15, 0.15 and 0.35 μg L- 1 for inorganic mercury, MeHg and EtHg, respectively. The developed method was validated by determination of the main analytical figures of merit and applied to the analysis of three certified reference materials. The online interfacing of liquid chromatography with photochemical-vapor generation-atomic fluorescence for mercury determination is simple, environmentally friendly, and represents an attractive alternative to the conventional tetrahydroborate (THB) system.

  7. An evaluation of mercury offloading in two Central California elasmobranchs.

    PubMed

    van Hees, Kelley E; Ebert, David A

    2017-03-02

    Elasmobranchs occupy high trophic levels, accumulate high concentrations of mercury in their tissues, and have high energetic levels of maternal investment to offspring, which may cause embryos to be exposed in utero to harmful concentrations of mercury. We investigated the maternal transfer of mercury in two common coastal elasmobranch species, Triakis semifasciata and Platyrhinoidis triseriata, to determine which reproductive parameters may influence mercury offloading, and whether embryos are at risk to mercury toxicity. Mercury concentration was measured in female muscle, female liver, and embryonic tissues. The behavior of mercury in adult female tissues differed between species, as liver mercury concentration was significantly correlated to muscle mercury concentration in P. triseriata but not in T. semifasciata. Embryos of both species were found with potentially harmful mercury concentrations in their muscle tissues. Embryo mercury concentration increased with female muscle mercury concentration, but the relationship to female liver mercury was more variable. The rate of mercury transfer and overall offloading potential were significantly greater in P. triseriata than T. semifasciata. It appears that female mercury concentration, either in muscle or liver, is an important influencing factor for mercury offloading, but the impact of the differing reproductive modes in these two species was less clear. More study on this subject will continue to elucidate the factors influencing mercury offloading in sharks and rays, and how contaminant risk affects populations on a whole.

  8. Mercury speciation and dispersion from an active gold mine at the West Wits area, South Africa.

    PubMed

    Lusilao-Makiese, J G; Tessier, E; Amouroux, D; Tutu, H; Chimuka, L; Weiersbye, I; Cukrowska, E M

    2016-01-01

    Total mercury (HgTOT), inorganic mercury (IHg), and methylmercury (MHg) were determined in dry season waters, sediments, and tailings from an active mine which has long history of gold exploitation. Although HgTOT in waters was generally low (0.03 to 19.60 ng L(-1)), the majority of the samples had proportions of MHg of at least 90 % of HgTOT which denotes a substantial methylation potential of the mine watersheds. Mercury was relatively high in tailing materials (up to 867 μg kg(-1)) and also in the mine sediments (up to 837 μg kg(-1)) especially in samples collected near tailing storage facilities and within a receiving water dam. Sediment profiles revealed mercury enrichment and enhanced methylation rate at deeper layers. The presence of IHg and decaying plants (organic matter) in the watersheds as well as the anoxic conditions of bulk sediments are believed to be some of the key factors favoring the mercury methylation at the site.

  9. Semiquantitative determination of total mercury in Pygocentrus nattereri Kner, 1858 and sediment at the plateau of Upper Paraguai River, Brazil.

    PubMed

    de Almeida Ferreira, Clautenes Maria; Egler, Silvia Gonçalves; Yallouz, Allegra Viviane; Ignácio, Áurea Regina Alves

    2017-05-01

    In this study an environmental assessment of contamination by total mercury (THg) was carried out at the Plateau of the Upper Paraguai River. Total mercury was evaluated in sediment and muscle of the red piranha Pygocentrus nattereri Kner, 1858, a piscivorous species at the top of the food chain consumed for subsistence and commercially. THg concentrations were below national guidelines established by WHO for sediments (100 ng g(-1)) and fish (100-600 ng g(-1)) for most of the sampled sites. Two sites located downstream of artisanal diamond and gold mines had THg concentrations in fish equal or greater than 600 ng g(-1).

  10. Craters hosting radar-bright deposits in Mercury's north polar region: Areas of persistent shadow determined from MESSENGER images

    NASA Astrophysics Data System (ADS)

    Chabot, Nancy L.; Ernst, Carolyn M.; Harmon, John K.; Murchie, Scott L.; Solomon, Sean C.; Blewett, David T.; Denevi, Brett W.

    2013-01-01

    Radar-bright features near Mercury's poles were discovered in Earth-based radar images and proposed to be water ice present in permanently shadowed areas. Images from MESSENGER's one-year primary orbital mission provide the first nearly complete view of Mercury's north polar region, as well as multiple images of the surface under a range of illumination conditions. We find that radar-bright features near Mercury's north pole are associated with locations persistently shadowed in MESSENGER images. Within 10° of the pole, almost all craters larger than 10 km in diameter host radar-bright deposits. There are several craters located near Mercury's north pole with sufficiently large diameters to enable long-lived water ice to be thermally stable at the surface within regions of permanent shadow. Craters located farther south also host radar-bright deposits and show a preference for cold-pole longitudes; thermal models suggest that a thin insulating layer is required to cover these deposits if the radar-bright material consists predominantly of long-lived water ice. Many small (<10 km diameter) and low-latitude (extending southward to 66°N) craters host radar-bright material, and water ice may not be thermally stable in these craters for ~1 Gy, even beneath an insulating layer. The correlation of radar-bright features with persistently shadowed areas is consistent with the deposits being composed of water ice, and future thermal modeling of small and low-latitude craters has the potential to further constrain the nature, source, and timing of emplacement of the radar-bright material.

  11. MESSENGER: Exploring Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Krimigis, Stamatios M.; Acuna, Mario H.; Anderson, Brian J.; Baker, Daniel N.; Koehn, Patrick L.; Korth, Haje; Levi, Stefano; Mauk, Barry H.; Solomon, Sean C.; Zurbuchen, Thomas H.

    2005-01-01

    driving field-aligned electric currents. However, these field-aligned currents do not close in an ionosphere, but in some other manner. In addition to the insights- into magnetospheric physics offered by study of the solar wind - Mercury system, quantitative specification of the "external" magnetic field generated by magnetospheric currents is necessary for accurate determination of the strength and multi-polar decomposition of Mercury s intrinsic magnetic field. MESSENGER S highly capable instrumentation and broad orbital coverage will greatly advance our understanding of both the origin of Mercury s magnetic field and the acceleration of charged particles in small magnetospheres. In. this article, we review what is known 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.

  12. Mercury Inhibits Soil Enzyme Activity in a Lower Concentration than the Guideline Value.

    PubMed

    Mahbub, Khandaker Rayhan; Krishnan, Kannan; Megharaj, Mallavarapu; Naidu, Ravi

    2016-01-01

    Three soil types - neutral, alkaline and acidic were experimentally contaminated with nine different concentrations of inorganic mercury (0, 5, 10, 50, 100, 150, 200, 250, 300 mg/kg) to derive effective concentrations of mercury that exert toxicity on soil quality. Bioavailability of mercury in terms of water solubility was lower in acidic soil with higher organic carbon. Dehydrogenase enzyme activity and nitrification rate were chosen as indicators to assess soil quality. Inorganic mercury significantly inhibited (p < 0.001) microbial activities in the soils. The critical mercury contents (EC10) were found to be less than the available safe limits for inorganic mercury which demonstrated inadequacy of existing guideline values.

  13. Accuracy of a method based on atomic absorption spectrometry to determine inorganic arsenic in food: Outcome of the collaborative trial IMEP-41.

    PubMed

    Fiamegkos, I; Cordeiro, F; Robouch, P; Vélez, D; Devesa, V; Raber, G; Sloth, J J; Rasmussen, R R; Llorente-Mirandes, T; Lopez-Sanchez, J F; Rubio, R; Cubadda, F; D'Amato, M; Feldmann, J; Raab, A; Emteborg, H; de la Calle, M B

    2016-12-15

    A collaborative trial was conducted to determine the performance characteristics of an analytical method for the quantification of inorganic arsenic (iAs) in food. The method is based on (i) solubilisation of the protein matrix with concentrated hydrochloric acid to denature proteins and allow the release of all arsenic species into solution, and (ii) subsequent extraction of the inorganic arsenic present in the acid medium using chloroform followed by back-extraction to acidic medium. The final detection and quantification is done by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS). The seven test items used in this exercise were reference materials covering a broad range of matrices: mussels, cabbage, seaweed (hijiki), fish protein, rice, wheat, mushrooms, with concentrations ranging from 0.074 to 7.55mgkg(-1). The relative standard deviation for repeatability (RSDr) ranged from 4.1 to 10.3%, while the relative standard deviation for reproducibility (RSDR) ranged from 6.1 to 22.8%.

  14. A new capillary electrophoresis buffer for determining organic and inorganic anions in electroplating bath with surfactant additives.

    PubMed

    Sun, H; Lau, K M; Fung, Y S

    2010-05-07

    Monitoring of trace impurities in electroplating bath is needed to meet EU requirements for WEEE and RoHS and for quality control of electrodeposits. Methods using IC and 100% aqueous CE buffer were found producing non-repeatable results attributed to interference of surfactants and major methanesulphonate anion. A new CE buffer containing 1.5mM tetraethylenepentaamine, 3mM 1,3,5-benzenetricarboxylic acid and 15 mM Tris in 20% (v/v) methanol at pH=8.4 was shown to enhance the separation window, reduce interaction between buffer and bath constituents, and give satisfactory repeatability with baseline separation for 14 organic and inorganic anions within 14 min, good repeatability for migration time (0.32-0.57% RSD), satisfactory peak area and peak height (2.9-4.5 and 3-4.7% respectively), low detection limit (S/N=2, 20-150 ppb), and wide working ranges (0.1-100 ppm). The CE buffer with 20% (v/v) methanol has demonstrated its capability for identifying anion impurities causing problem in aged tin bath and the use of only 10-fold dilution to produce reliable results for quality assessment in plating bath containing high surfactant additives.

  15. Photosynthetic kinetics determine the outcome of competition for dissolved inorganic carbon by freshwater microalgae: implications for acidified lakes.

    PubMed

    Williams, T G; Turpin, D H

    1987-09-01

    Photosynthetic kinetics with respect to dissolved inorganic carbon were used to predict the outcome of competition for DIC between the green alga Selenastrum minutum and the cyanobacterium Synechococcus leopoliensis at pH 6.2, 7.5, and 10. Based on measured values of the maximum rate of photosynthesis, the half-saturation value of photosynthesis with respect to DIC (K 1(2/DIC) ), and the DIC compensation point, it was predicted that S. leopoliensis would lower the steady-state DIC concentration below the DIC compensation point of S. minutum. This should result in competitive displacement of the green alga at a rate equivalent to the chemostat dilution rate. This prediction was validated by carrying out competition experiments over the range of pH. These results suggest that the low levels of DIC in air-equilibrated acidified lakes may be an important rate-limiting resource and hence affect phytoplankton community structure. Furthermore, the low levels of DIC in these systems may be below the DIC compensation point for some species, thereby precluding their growth at acid pH solely as a function of DIC limitation. The potential importance of DIC in shaping phytoplankton community structure in acidified systems is discussed.

  16. Parallel determination of enzyme activities and in vivo fluxes in Brassica napus embryos grown on organic or inorganic nitrogen source.

    PubMed

    Junker, Björn H; Lonien, Joachim; Heady, Lindsey E; Rogers, Alistair; Schwender, Jörg

    2007-01-01

    After the completion of the genomic sequencing of model organisms, numerous post-genomic studies, integrating transcriptome and metabolome data, are aimed at developing a more complete understanding of cell physiology. Here, we measure in vivo metabolic fluxes by steady state labeling, and in parallel, the activity of enzymes in central metabolism in cultured developing embryos of Brassica napus. Embryos were grown on either the amino acids glutamine and alanine as an organic nitrogen source, or on ammonium nitrate as an inorganic nitrogen source. The type of nitrogen made available to developing embryos caused substantial differences in fluxes associated with the tricarboxylic acid cycle, including flux reversion. The changes observed in enzyme activity were not consistent with our estimates of metabolic flux. Furthermore, most extractable enzyme activities are in large surplus relative to the requirements for the observed in vivo fluxes. The results demonstrate that in this model system the metabolic response of central metabolism to changes in environmental conditions can be achieved largely without regulatory reprogramming of the enzyme machinery.

  17. Got Mercury?

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    Many lamps used in various spacecraft contain elemental mercury, which is efficiently absorbed through the lungs as a vapor. The liquid metal vaporizes slowly at room temperature, but may be completely vaporized when lamps are operating. Because current spacecraft environmental control systems are unable to remove mercury vapors, we considered short-term and long-term exposures. Using an existing study, we estimated mercury vapor releases from lamps that are not in operation during missions lasting less than or equal to 30 days; whereas we conservatively assumed complete vaporization from lamps that are operating or being used during missions lasing more than 30 days. Based on mercury toxicity, the Johnson Space Center's Toxicology Group recommends stringent safety controls and verifications for any hardware containing elemental mercury that could yield airborne mercury vapor concentrations greater than 0.1 mg/m3 in the total spacecraft atmosphere for exposures lasting less than or equal to 30 days, or concentrations greater than 0.01 mg/m3 for exposures lasting more than 30 days.

  18. Elemental mercury poisoning in a family of seven.

    PubMed

    Cherry, Debra; Lowry, Larry; Velez, Larissa; Cotrell, Cindy; Keyes, D Christopher

    2002-01-01

    Mercury poisoning in children is rare but may have devastating health consequences when exposure is unrecognized. Mercury occurs in three forms: elemental, inorganic, and organic. Elemental mercury (Hg(0)) vapor may become volatile following an accidental spill and may be readily absorbed from the lungs. The following case study describes how the poison center, health department, physicians, and others worked together to treat a family with long-term exposure to elemental mercury vapor in the home. Identification and prevention of this type of exposure in the community are discussed.

  19. [Human exposure to mercury in the Brazilian Amazon: a historical perspective].

    PubMed

    Gonçalves, Aguinaldo; Gonçalves, Neusa Nunes da Silva e

    2004-12-01

    The objective of the present article was to present the most important data generated by a multicentric study carried out by Brazilian researchers who, with the support of national and international institutions, worked during the 1990s to describe human exposure to mercury in gold mining areas in the Brazilian Amazon. Three sets of procedures were followed with residents of the Tocantins and Xingu river basins: (1) clinical examination, based on a standardized protocol and performed by a single researcher, in order to identify five basic levels of contamination; (2) determination of mercury levels in blood, hair, and urine, using atomic absorption spectrophotometry (Xingu Project); and (3) investigation of genotoxicity by using four cytogenetic indicators. During the first stage, 41 individuals were studied. Mercury was found in miners and their family members. Contamination was significantly associated with occupation and showed a differential correlation with genotoxicity indicators. After that, the Xingu project, which encompassed 625 individuals, focused on 417 Kayapó natives from the Gorotire and Djudjetiktire villages; 142 miners; and 66 riverine individuals (ribeirinhos). The highest levels of methylmercury in hair and total mercury in blood and urine were found among the Indian population. Contamination with inorganic forms of mercury was also observed in the blood, hair, and urine of Indians. Following a specific recommendation from the World Health Organization, special attention was given to pregnant Gorotire and Djudjetiktire women, who, although not directly exposed to mercury vapors, showed considerable levels of mercury intoxication. Despite this worrisome scenario, a number of social achievements in the 1990s point to new standards of dignity in health care and of social ethics in Brazil that could benefit everyone, including the victims of environmental injury.

  20. Is the lobster cockroach Nauphoeta cinerea a valuable model for evaluating mercury induced oxidative stress?

    PubMed

    Rodrigues, N R; Nunes, M E M; Silva, D G C; Zemolin, A P P; Meinerz, D F; Cruz, L C; Pereira, A B; Rocha, J B T; Posser, T; Franco, J L

    2013-08-01

    Organic and inorganic forms of mercury are highly neurotoxic environmental contaminants. The exact mechanisms involved in mercury neurotoxicity are still unclear. Oxidative stress appears to play central role in this process. In this study, we aimed to validate an insect-based model for the investigation of oxidative stress during mercury poisoning of lobster cockroach Nauphoeta cinerea. The advantages of using insects in basic toxicological studies include the easier handling, rapid proliferation/growing and absence of ethical issues, comparing to rodent-based models. Insects received solutions of HgCl2 (10, 20 and 40mgL(-1) in drinking water) for 7d. 24h after mercury exposure, animals were euthanized and head tissue samples were prepared for oxidative stress related biochemical determinations. Mercury exposure caused a concentration dependent decrease in survival rate. Cholinesterase activity was unchanged. Catalase activity was substantially impaired after mercury treatment 40mgL(-1). Likewise, GST had a significant decrease, comparing to control. Peroxidase and thioredoxin reductase activity was inhibited at concentrations of 20mgL(-1) and 40mgL(-1) comparing to control. These results were accompanied by decreased GSH levels and increased hydroperoxide and TBARS formation. In conclusion, our results show that mercuric compounds are able to induce oxidative stress signs in insect by modulating survival rate as well as inducing impairments on important antioxidant systems. In addition, our data demonstrates for the first time that Nauphoeta cinerea represents an interesting animal model to investigate mercury toxicity and indicates that the GSH and thioredoxin antioxidant systems plays central role in Hg induced toxicity in insects.

  1. Determination of Mercury in Fish: A Low-Cost Implementation of Cold-Vapor Atomic Absorbance for the Undergraduate Environmental Chemistry Laboratory

    ERIC Educational Resources Information Center

    Niece, Brian K.; Hauri, James F.

    2013-01-01

    Mercury is a known neurotoxin that is particularly harmful to children and unborn fetuses. Consumption of contaminated fish is one major route of mercury exposure. This laboratory experiment gives students an opportunity to measure mercury concentrations in store-bought seafood and compare the results to suggested exposure limits. The U.S.…

  2. Thimerosal distribution and metabolism in neonatal mice: comparison with methyl mercury.

    PubMed

    Zareba, Grazyna; Cernichiari, Elsa; Hojo, Rieko; Nitt, Scott Mc; Weiss, Bernard; Mumtaz, Moiz M; Jones, Dennis E; Clarkson, Thomas W

    2007-01-01

    Thimerosal, which releases the ethyl mercury radical as the active species, has been used as a preservative in many currently marketed vaccines throughout the world. Because of concerns that its toxicity could be similar to that of methyl mercury, it is no longer incorporated in many vaccines in the United States. There are reasons to believe, however, that the disposition and toxicity of ethyl mercury compounds, including thimerosal, may differ substantially from those of the methyl form. The current study sought to compare, in neonatal mice, the tissue concentrations, disposition and metabolism of thimerosal with that of methyl mercury. ICR mice were given single intramuscular injections of thimerosal or methyl mercury (1.4 mg Hg kg(-1)) on postnatal day 10 (PND 10). Tissue samples were collected daily on PND 11-14. Most analysed tissues demonstrated different patterns of tissue distribution and a different rate of mercury decomposition. The mean organic mercury in the brain and kidneys was significantly lower in mice treated with thimerosal than in the methyl mercury-treated group. In the brain, thimerosal-exposed mice showed a steady decrease of organic mercury levels following the initial peak, whereas in the methyl mercury-exposed mice, concentrations peaked on day 2 after exposure. In the kidneys, thimerosal-exposed mice retained significantly higher inorganic mercury levels than methyl mercury-treated mice. In the liver both organic and inorganic mercury concentrations were significantly higher in thimerosal-exposed mice than in the methyl mercury group. Ethyl mercury was incorporated into growing hair in a similar manner to methyl mercury. The data showing significant kinetic differences in tissue distribution and metabolism of mercury species challenge the assumption that ethyl mercury is toxicologically identical to methyl mercury.

  3. Fulvic acid-sulfide ion competition for mercury ion binding in the Florida everglades

    USGS Publications Warehouse

    Reddy, M.M.; Aiken, G.R.

    2001-01-01

    Negatively charged functional groups of fulvic acid compete with inorganic sulfide ion for mercury ion binding. This competition is evaluated here by using a discrete site-electrostatic model to calculate mercury solution speciation in the presence of fulvic acid. Model calculated species distributions are used to estimate a mercury-fulvic acid apparent binding constant to quantify fulvic acid and sulfide ion competition for dissolved inorganic mercury (Hg(II)) ion binding. Speciation calculations done with PHREEQC, modified to use the estimated mercury-fulvic acid apparent binding constant, suggest that mercury-fulvic acid and mercury-sulfide complex concentrations are equivalent for very low sulfide ion concentrations (about 10-11 M) in Everglades' surface water. Where measurable total sulfide concentration (about 10-7 M or greater) is present in Everglades' surface water, mercury-sulfide complexes should dominate dissolved inorganic mercury solution speciation. In the absence of sulfide ion (for example, in oxygenated Everglades' surface water), fulvic acid binding should dominate Everglades' dissolved inorganic mercury speciation.

  4. Determination of trace mercury by solid substrate room temperature phosphorescence quenching method based on lead carboxymethyl cellulose (Pb(CMC)(2)) particles containing luminescent salicyl fluorones molecules.

    PubMed

    Liu, Jia-Ming; Wu, Ai-Hong; Xu, Huan-Huan; Wang, Qing-Hua; Li, Long-Di; Zhu, Guo-Hui

    2005-01-30

    Luminescent particles of lead carboxymethyl cellulose (Pb(CMC)(2)), which contains salicyl fluorones (THBF), Pb(CMC)(2)-THBF, were synthesized by sol-gel method. Pb(CMC)(2)-THBF can emit intense and stable solid substrate room temperature phosphorescence (SS-RTP) on filter paper. EDTA can chelate the Pb(2+) in Pb(CMC)(2)-THBF, causing it decompose into aqueous soluble components PbY(2-), CMC(-) and THBF, and these components can react with Hg(2+) to form (CMC)(2)Hg-THBF, causing decrease of phosphorescence intensity. Based on the facts above, a new method for the determination of trace mercury by SS-RTP quenching method was established. The linear range of this method is 2.0-40.0fgspot(-1) (5.0-100.0pgml(-1)) of Hg(2+), with a detection limit (LD) of 0.26fgspot(-1), and the regression equation of working curve is [Formula: see text] (fgspot(-1), 0.4mul spot(-1)), r = 0.9994. This method has been applied to the determination of trace mercury in water sample with satisfactory results. The mechanism of SS-RTP emission is also discussed.

  5. Determination of cadmium, lead and mercury residual levels in meat of canned light tuna (Katsuwonus pelamis and Thunnus albacares) and fresh little tunny (Euthynnus alletteratus) in Libya

    PubMed Central

    Abolghait, S.K.; Garbaj, A.M.

    2015-01-01

    Surveillance for mercury (Hg), lead (Pb) and cadmium (Cd) contamination in tuna products is crucial for consumer food safety. Hg, Pb and Cd contaminants were monitored in a total of 60 specimens of fresh little tunny (Euthynnus alletteratus) and popular brands of skipjack and yellowfin (Katsuwonus pelamis and Thunnus albacares) canned tuna commercially available in Tripoli, Libya. Direct Mercury Analyzer (DMA-80) was implemented for determination of total Hg level and graphite furnace atomic absorption spectrometry (GFAAS) was employed for determination of Cd and Pb concentrations. The results indicated that Hg had the highest concentration level and Cd had the lowest concentration level either in tested canned tuna or fresh little tunny samples. The average concentration of Hg in fresh little tunny samples was 1.185 ± 0.968 mg kg-1 wet weight (ww) and often exceeded the standard permissible limit. In addition, canned yellowfin tuna had the lowest levels of Cd (0.027 ± 0.026 mg kg-1 ww), Pb (0.075 ± 0.071) and Hg (0.163 ± 0.122 mg kg-1 ww). Results of the current surveillance indicated that canned skipjack and yellowfin tuna sold in Tripoli markets show contaminant levels well under the European thresholds adopted for Cd, Pb and Hg. However, consumption of large quantities of Mediterranean little tunny products significantly increases human exposure to the risk of Hg toxicity. PMID:26623379

  6. Speciation and determination of ultra trace amounts of inorganic tellurium in environmental water samples by dispersive liquid-liquid microextraction and electrothermal atomic absorption spectrometry.

    PubMed

    Najafi, Nahid Mashkouri; Tavakoli, Hamed; Alizadeh, Reza; Seidi, Shahram

    2010-06-18

    A simple and powerful method has been developed for the rapid and selective determination of Te(IV) and Te(VI), employing dispersive liquid-liquid microextraction combined with electrothermal atomic absorption spectrometry using palladium as permanent modifier. Under acidic conditions pH 1, only Te(IV) can form a complex with ammonium pyrrolidine dithiocarbamate (APDC) and therefore be extracted into fine droplets of carbon tetrachloride (extraction solvent) which are dispersed with ethanol into the water sample solution. After centrifugation, Te(IV) was determined in the sedimented organic phase while Te(VI) remained in the aqueous phase. Total inorganic tellurium was determined after the reduction of the Te(VI) to Te(IV). Te(VI) was calculated as the difference between the measured total inorganic tellurium and Te(IV) content. The effective parameters for improving the efficiency of microextraction process were investigated by using experimental and central composite designs. Under optimal conditions the enrichment factor was 125 and the calibration graph was linear in the range of 0.015-1 ng mL(-1) with detection limit and characteristic mass of 0.004 ng mL(-1) and 0.033 pg, respectively. The relative standard deviation for 0.5 ng mL(-1) of tellurium measurement was 3.6% (n=6) at ash and atomization temperature, 900 and 2600 degrees C, respectively. The recoveries of spiked Te(IV) and Te(VI) to the environmental water samples were 89.6-101.3% and 96.6-99.1%, respectively. The accuracy is also evaluated by applying the proposed method to certified reference material (NIST SRM 1643e), for which the result was in a good agreement with the certified values reported for this CRM (95% confidence level).

  7. Screen-printed electrode based electrochemical detector coupled with ionic liquid dispersive liquid-liquid microextraction and microvolume back-extraction for determination of mercury in water samples.

    PubMed

    Fernández, Elena; Vidal, Lorena; Martín-Yerga, Daniel; Blanco, María del Carmen; Canals, Antonio; Costa-García, Agustín

    2015-04-01

    A novel approach is presented, whereby gold nanostructured screen-printed carbon electrodes (SPCnAuEs) are combined with in-situ ionic liquid formation dispersive liquid-liquid microextraction (in-situ IL-DLLME) and microvolume back-extraction for the determination of mercury in water samples. In-situ IL-DLLME is based on a simple metathesis reaction between a water-miscible IL and a salt to form a water-immiscible IL into sample solution. Mercury complex with ammonium pyrrolidinedithiocarbamate is extracted from sample solution into the water-immiscible IL formed in-situ. Then, an ultrasound-assisted procedure is employed to back-extract the mercury into 10 µL of a 4 M HCl aqueous solution, which is finally analyzed using SPCnAuEs. Sample preparation methodology was optimized using a multivariate optimization strategy. Under optimized conditions, a linear range between 0.5 and 10 µg L(-1) was obtained with a correlation coefficient of 0.997 for six calibration points. The limit of detection obtained was 0.2 µg L(-1), which is lower than the threshold value established by the Environmental Protection Agency and European Union (i.e., 2 µg L(-1) and 1 µg L(-1), respectively). The repeatability of the proposed method was evaluated at two different spiking levels (3 and 10 µg L(-1)) and a coefficient of variation of 13% was obtained in both cases. The performance of the proposed methodology was evaluated in real-world water samples including tap water, bottled water, river water and industrial wastewater. Relative recoveries between 95% and 108% were obtained.

  8. Gold-coated silica as a preconcentration phase for the determination of total dissolved mercury in natural waters using atomic fluorescence spectrometry.

    PubMed

    Leopold, Kerstin; Foulkes, Michael; Worsfold, Paul J

    2009-05-01

    A novel solid-phase preconcentration method is reported, using in-house gold-coated silica adsorbent packed in a microcolumn, for the determination of dissolved mercury in natural waters by atomic fluorescence spectrometry (AFS). The adsorbent was prepared by chemical reduction of a Au(III) solution with hydroxylamine in the presence of suspended silica particles. The resulting Au nanoparticles on the silica surface were highly efficient for adsorbing different mercury species from acidified waters without additional reagents. The acidified aqueous samples were passed over the microcolumn, either incorporated in a fully automated flow injection (FI) system directly coupled to the AFS or as part of a portable FI system for in situ preconcentration. After rinsing and drying of the column, Hg(0) was released by heating and directed to the AFS cell for quantification. The method offers significant advantages because no reagents are needed for species conversion, preconcentration, sample storage, or desorption and therefore the risk of contamination is minimized and blank values are lowered. This results in a low detection limit of 180 pg L(-1) using a sample volume of only 7 mL and good reproducibility, with relative standard deviations <3.2% (n = 10, [Hg] = 5 ng L(-1)). Recoveries were all >90% in spiked river waters (spiked [Hg] = 0, 1, 5, 10 ng L(-1)), and the experimental value for the certified reference material ORMS-4 (elevated mercury in river water) was 22.3 +/- 2.6 ng Hg L(-1) which was in good agreement with the certified value of 22.0 +/- 1.6 ng Hg L(-1) (recovery = 101%). The method was successfully applied to seven different natural waters and wastewaters ([Hg] 0.5-4.6 ng L(-1)) from south west England.

  9. Mercury toxicity. Agency for Toxic Substance and Disease Registry

    SciTech Connect

    Not Available

    1992-12-01

    Because mercury has several forms and because it produces subtle effects at chronic low-level exposures, mercury toxicity can be a difficult diagnosis to establish. Elemental mercury vapor accounts for most occupational and many accidental exposures. The main source of organic methyl mercury exposure in the general population is fish consumption. Children are at increased risk of exposure to elemental mercury vapor in the home because it tends to settle to the floor. The chemical and physical forms of mercury determine its absorption, metabolism, distribution and excretion pathways. The central nervous system and kidneys are key targets of mercury toxicity. Chelation therapy has been used successfully in treating patients who have ingested mercury salts or inhaled elemental mercury. There is no antidote for patients poisoned with organic mercury.7 references.

  10. [Determination of inorganic elements in rat serum, and vegetable and fruit ferment liquid by ICP-MS].

    PubMed

    Li, Xiang-yun; Lian, Hong-zhen; Chen, Yi-jun; Hu, Xin; Mao, Li; Lu, Ming; Cai, Yun-qing

    2008-09-01

    In the present paper, the contents of thirteen inorganic elements in rat serum, and vegetable and fruit ferment liquid (VFFL) were measured by ICP-MS in order to study the anti-tumor effect of VFFL. Serum or VFFL was digested in nitric and perchloric acids at room temperature and then heated until dryness. The residue was dissolved with 1% (phi) nitric acid prior to ICP-MS analysis. The element contents were quantitated by using 45Sc, 103Rh and 187Re as the internal standards, respectively, according to the rule of close mass number. Certificate references bovine serum (GBW(E)090006) and tea (GBW070605) were employed to validate the proposed method, and the analysis results of most elements in two certificate references were in agreement with their reference values. The intra-day and inter-day precisions of the method in terms of relative standard deviation (RSD) were mainly below 10% and below 15%, respectively. The spiked recoveries for most of studied elements were 80%-110% in rat serum and 90%-120% in VFFL. This method was rapid, highly sensitive, and especially suitable to being applied to small quantity of biological samples with greatly different elements contents. Therefore, we measured the content of thirteen elements in the sera of rats, where in were induced liver cancer by revulsant, and the rate were fed with different dosage of VFFL in intragastric infusion at the same time. It was preliminarily found that the concentrations of some elements in sera of different experiment groups of rats were significantly different, implying the potential anti-tumor effects of VFFL.

  11. Ubiquitous dissolved inorganic carbon assimilation by marine bacteria in the Pacific Northwest coastal ocean as determined by stable isotope probing.

    PubMed

    DeLorenzo, Suzanne; Bräuer, Suzanna L; Edgmont, Chelsea A; Herfort, Lydie; Tebo, Bradley M; Zuber, Peter

    2012-01-01

    In order to identify bacteria that assimilate dissolved inorganic carbon (DIC) in the northeast Pacific Ocean, stable isotope probing (SIP) experiments were conducted on water collected from 3 different sites off the Oregon and Washington coasts in May 2010, and one site off the Oregon Coast in September 2008 and March 2009. Samples were incubated in the dark with 2 mM (13)C-NaHCO(3), doubling the average concentration of DIC typically found in the ocean. Our results revealed a surprising diversity of marine bacteria actively assimilating DIC in the dark within the Pacific Northwest coastal waters, indicating that DIC fixation is relevant for the metabolism of different marine bacterial lineages, including putatively heterotrophic taxa. Furthermore, dark DIC-assimilating assemblages were widespread among diverse bacterial classes. Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes dominated the active DIC-assimilating communities across the samples. Actinobacteria, Betaproteobacteria, Deltaproteobacteria, Planctomycetes, and Verrucomicrobia were also implicated in DIC assimilation. Alteromonadales and Oceanospirillales contributed significantly to the DIC-assimilating Gammaproteobacteria within May 2010 clone libraries. 16S rRNA gene sequences related to the sulfur-oxidizing symbionts Arctic96BD-19 were observed in all active DIC assimilating clone libraries. Among the Alphaproteobacteria, clones related to the ubiquitous SAR11 clade were found actively assimilating DIC in all samples. Although not a dominant contributor to our active clone libraries, Betaproteobacteria, when identified, were predominantly comprised of Burkholderia. DIC-assimilating bacteria among Deltaproteobacteria included members of the SAR324 cluster. Our research suggests that DIC assimilation is ubiquitous among many bacterial groups in the coastal waters of the Pacific Northwest marine environment and may represent a significant metabolic process.

  12. Determination of the origin of dissolved inorganic carbon in groundwater around a reclaimed landfill in Otwock using stable carbon isotopes.

    PubMed

    Porowska, Dorota

    2015-05-01

    Chemical and isotopic analyses of groundwater from piezometers located around a reclaimed landfill in Otwock (Poland) were performed in order to trace the origin of dissolved inorganic carbon (DIC) in the groundwater. Due to differences in the isotopic composition of carbon from different sources, an analysis of stable carbon isotopes in the groundwater, together with the Keeling plot approach and a two-component mixing model allow us to evaluate the relative contributions of carbon from these sources in the groundwater. In the natural (background) groundwater, DIC concentrations and the isotopic composition of DIC (δ(13)CDIC) comes from two sources: decomposition of organic matter and carbonate dissolution within the aquifer sediments, whereas in the leachate-contaminated groundwater, DIC concentrations and δ(13)CDIC values depend on the degradation of organic matter within the aquifer sediments and biodegradation of organic matter stored in the landfill. From the mixing model, about 4-54% of the DIC pool is derived from organic matter degradation and 96-46% from carbonate dissolution in natural conditions. In the leachate-contaminated groundwater, about 20-53% of the DIC is derived from organic matter degradation of natural origin and 80-47% from biodegradation of organic matter stored in the landfill. Partial pressure of CO2 (P CO2) was generally above the atmospheric, hence atmospheric CO2 as a source of carbon in DIC pool was negligible in the aquifer. P CO2 values in the aquifer in Otwock were always one to two orders of magnitude above the atmospheric P CO2, and thus CO2 escaped directly into the vadose zone.

  13. Determination of copper and mercury in phosphate fertilizers employing direct solid sampling analysis and high resolution continuum source graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    de Oliveira Souza, Sidnei; François, Luciane Luiza; Borges, Aline Rocha; Vale, Maria Goreti Rodrigues; Araujo, Rennan Geovanny Oliveira

    2015-12-01

    The present study proposes the determination of copper and mercury in phosphate fertilizers by direct solid sampling analysis (SS) employing high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). For Cu determination, two analytical lines were used: 327.3960 nm and 249.2146 nm. Hg determination was carried out on the line 253.6521 nm and 100 μg KMnO4 was used as chemical modifier. The optimal