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Sample records for methyl mercury exposure

  1. Effects of methyl mercury exposure on pancreatic beta cell development and function.

    Science.gov (United States)

    Schumacher, Lauren; Abbott, Louise C

    2017-01-01

    Methyl mercury is an environmental contaminant of worldwide concern. Since the discovery of methyl mercury exposure due to eating contaminated fish as the underlying cause of the Minamata disaster, the scientific community has known about the sensitivity of the developing central nervous system to mercury toxicity. Warnings are given to pregnant women and young children to limit consumption of foods containing methyl mercury to protect the embryonic, fetal and postnatally developing central nervous system. However, evidence also suggests that exposure to methyl mercury or various forms of inorganic mercury may also affect development and function of other organs. Numerous reports indicate a worldwide increase in diabetes, particularly type 2 diabetes. Quite recently, methyl mercury has been shown to have adverse effects on pancreatic beta (β) cell development and function, resulting in insulin resistance and hyperglycemia and may even lead to the development of diabetes. This review discusses possible mechanisms by which methyl mercury exposure may adversely affect pancreatic β cell development and function, and the role that methyl mercury exposure may have in the reported worldwide increase in diabetes, particularly type 2 diabetes. While additional information is needed regarding associations between mercury exposure and specific mechanisms of the pathogenesis of diabetes in the human population, methyl mercury's adverse effects on the body's natural sources of antioxidants suggest that one possible therapeutic strategy could involve supplementation with antioxidants. Thus, it is important that additional investigation be undertaken into the role of methyl mercury exposure and reduced pancreatic β cell function. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Effects of methyl mercury exposure on the growth of juvenile common loons

    Science.gov (United States)

    Kenow, K.P.; Gutreuter, S.; Hines, R.K.; Meyer, M.W.; Fournier, F.; Karasov, W.H.

    2003-01-01

    We conducted a dose-response laboratory study to quantify the level of mercury exposure associated with negative effects on the development of common loon chicks reared in captivity from hatch to 105 days. A dose regimen was implemented that provided exposure levels that bracketed relevant exposure levels of methyl mercury found in loon chicks across North America. We observed no overt signs of mercury toxicosis and detected no significant effect of dietary mercury exposure on growth or food consumption. However, asymptotic mass was lower in chicks that hatched from eggs collected from nests on low pH lakes relative to eggs from neutral pH lakes. Rapid excretion of methyl mercury during feather growth likely provides loon chicks protection from methyl mercury toxicity and may explain the lack of convincing toxicological findings in this study. Lake-source effects suggest that in ovo exposure to methyl mercury or other factors related to lake pH have consequences on chick development.

  3. Modulation of vasodilator response via the nitric oxide pathway after acute methyl mercury chloride exposure in rats.

    Science.gov (United States)

    Omanwar, S; Saidullah, B; Ravi, K; Fahim, M

    2013-01-01

    Mercury exposure induces endothelial dysfunction leading to loss of endothelium-dependent vasorelaxation due to decreased nitric oxide (NO) bioavailability via increased oxidative stress. Our aim was to investigate whether acute treatment with methyl mercury chloride changes the endothelium-dependent vasodilator response and to explore the possible mechanisms behind the observed effects. Wistar rats were treated with methyl mercury chloride (5 mg/kg, po.). The methyl mercury chloride treatment resulted in an increased aortic vasorelaxant response to acetylcholine (ACh). In methyl-mercury-chloride-exposed rats, the % change in vasorelaxant response of ACh in presence of Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME; 10(-4) M) was significantly increased, and in presence of glybenclamide (10(-5) M), the response was similar to that of untreated rats, indicating the involvement of NO and not of endothelium-derived hyperpolarizing factor (EDHF). In addition, superoxide dismutase (SOD) + catalase treatment increased the NO modulation of vasodilator response in methyl-mercury-chloride-exposed rats. Our results demonstrate an increase in the vascular reactivity to ACh in aorta of rats acutely exposed to methyl mercury chloride. Methyl mercury chloride induces nitric oxide synthase (NOS) and increases the NO production along with inducing oxidative stress without affecting the EDHF pathway.

  4. Modulation of Vasodilator Response via the Nitric Oxide Pathway after Acute Methyl Mercury Chloride Exposure in Rats

    Directory of Open Access Journals (Sweden)

    S. Omanwar

    2013-01-01

    Full Text Available Mercury exposure induces endothelial dysfunction leading to loss of endothelium-dependent vasorelaxation due to decreased nitric oxide (NO bioavailability via increased oxidative stress. Our aim was to investigate whether acute treatment with methyl mercury chloride changes the endothelium-dependent vasodilator response and to explore the possible mechanisms behind the observed effects. Wistar rats were treated with methyl mercury chloride (5 mg/kg, po.. The methyl mercury chloride treatment resulted in an increased aortic vasorelaxant response to acetylcholine (ACh. In methyl-mercury-chloride-exposed rats, the % change in vasorelaxant response of ACh in presence of Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME; 10-4 M was significantly increased, and in presence of glybenclamide (10-5 M, the response was similar to that of untreated rats, indicating the involvement of NO and not of endothelium-derived hyperpolarizing factor (EDHF. In addition, superoxide dismutase (SOD + catalase treatment increased the NO modulation of vasodilator response in methyl-mercury-chloride-exposed rats. Our results demonstrate an increase in the vascular reactivity to ACh in aorta of rats acutely exposed to methyl mercury chloride. Methyl mercury chloride induces nitric oxide synthase (NOS and increases the NO production along with inducing oxidative stress without affecting the EDHF pathway.

  5. Methyl Mercury Exposure at Niigata, Japan: Results of Neurological Examinations of 103 Adults

    Directory of Open Access Journals (Sweden)

    Kimio Maruyama

    2012-01-01

    Full Text Available Background. Large-scale poisonings caused by methyl mercury (MeHg have occurred in Japan (Minamata in the 1950s and Niigata in the 1960s and Iraq (in the 1970s. The current WHO neurological risk standard for adult exposure (hair level: 50 μg/g was based partly on evidence from Niigata which did not consider any cases who were diagnosed later and/or exposed to low level of MeHg (hair mercury level less than 50 μg/g. Methods. Early in the Niigata epidemic in June 1965 there were two extensive surveys. From these two surveys, we examined 103 adults with hair mercury measurement who consulted two medical institutions. We compared the prevalence and the distribution of neurological signs related to MeHg poisoning between exposure categories. Result. We found 48 subjects with neurological signs related to MeHg poisoning who had hair mercury concentration less than 50 μg/g. Among the neurological signs, sensory disturbance of the bilateral distal extremities was observed more frequently, followed by disequilibrium, hearing impairment, and ataxia, in groups with hair MeHg concentration both below 50 μg/g and over 50 μg/g. Conclusion. The present study suggests the possibility that exposure to MeHg at levels below the current WHO limits could cause neurologic signs, in particular, sensory disturbance.

  6. Toward a Unified Understanding of Mercury and Methylated Mercury from the World's Oceans

    Science.gov (United States)

    McNutt, M. K.; Krabbenhoft, D. P.; Landing, W. M.; Sunderland, E. M.

    2012-12-01

    Marine fish and shellfish are the main source of toxic methylmercury exposure for humans. As recently as decade ago, very limited aqueous methylated mercury data were available from marine settings, resulting in a generally poor understanding of the processes controlling mercury in pelagic marine food webs. Recent oceanographic cruises have significantly improved availability of reliable measurements of methylated mercury and total mercury in seawater. This presentation will focus on vertical seawater profiles collected to depths 1000 m from three recent sampling efforts in collaboration with the CLIVAR Repeat Hydrography Program sponsored by NOAA including: 1) the northeastern Pacific (P16N cruise from Honolulu, Hawaii to Kodiak, Alaska); (2) the southern Indian Ocean (I5 cruise from Cape Town, South Africa, to Fremantle, Australia); and, (3) the Southern Ocean cruise (S4P from McMurdo, Antarctica, to Punta Arenas, Chile). Analytical results presented were all derived from the USGS Mercury Research Lab (http://wi.water.usgs.gov/mercury-lab). Supporting data derived from these cruises on water mass ages, nutrients, carbon and dissolved oxygen provide an opportunity to develop a stronger understanding of the biogeochemical factors controlling oceanic distributions of mercury and methylated mercury. Whole-water, median total mercury, and methylated mercury concentrations for the northern Pacific, southern Indian, and Southern Ocean were 1.10, 0.80, and 1.65 pM, , and 0.11, 0.08, and 0.32 pM, respectively. For all three oceans, vertical profiles of total mercury generally show the lowest concentrations in the surface mixed layer, and concentration maxima at the 700-1000 m depths. Surface depletion of total mercury is attributed to photo-chemical reduction and evasion of gaseous elemental mercury as well as scavenging by settling particulate matter, the main vector of transport to the subsurface ocean. Methylated mercury in all the ocean profiles reveal distinct mid

  7. Methyl mercury exposure in Swedish women with high fish consumption

    International Nuclear Information System (INIS)

    Bjoernberg, Karolin Ask; Vahter, Marie; Grawe, Kierstin Petersson; Berglund, Marika

    2005-01-01

    We studied the exposure to methyl mercury (MeHg) in 127 Swedish women of childbearing age with high consumption of various types of fish, using total mercury (T-Hg) in hair and MeHg in blood as biomarkers. Fish consumption was assessed using a food frequency questionnaire (FFQ), including detailed information about consumption of different fish species, reflecting average intake during 1 year. We also determined inorganic mercury (I-Hg) in blood, and selenium (Se) in serum. The average total fish consumption, as reported in the food frequency questionnaire, was approximately 4 times/week (range 1.6-19 times/week). Fish species potentially high in MeHg, included in the Swedish dietary advisories, was consumed by 79% of the women. About 10% consumed such species more than once a week, i.e., more than what is recommended. Other fish species potentially high in MeHg, not included in the Swedish dietary advisories, was consumed by 54% of the women. Eleven percent never consumed fish species potentially high in MeHg. T-Hg in hair (median 0.70 mg/kg; range 0.08-6.6 mg/kg) was associated with MeHg in blood (median 1.7 μg/L; range 0.30-14 μg/L; r s =0.78; p s =0.32; p s =0.37; p s =0.35; p=0.002, respectively). I-Hg in blood (median 0.24 μg/L; range 0.01-1.6 μg/L) increased with increasing number of dental amalgam fillings. We found no statistical significant associations between the various mercury species measured and the Se concentration in serum. Hair mercury levels exceeded the levels corresponding to the EPA reference dose (RfD) of 0.1 μg MeHg/kg b.w. per day in 20% of the women. Thus, there seems to be no margin of safety for neurodevelopmental effects in fetus, for women with high fish consumption unless they decrease their intake of certain fish species

  8. Methyl mercury exposure in Swedish women with high fish consumption

    Energy Technology Data Exchange (ETDEWEB)

    Bjoernberg, Karolin Ask [Division of Metals and Health, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm (Sweden); Vahter, Marie [Division of Metals and Health, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm (Sweden); Grawe, Kierstin Petersson [Toxicology Division, National Food Administration, Box 622, SE-751 26 Uppsala (Sweden); Berglund, Marika [Division of Metals and Health, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm (Sweden)]. E-mail: Marika.Berglund@imm.ki.se

    2005-04-01

    We studied the exposure to methyl mercury (MeHg) in 127 Swedish women of childbearing age with high consumption of various types of fish, using total mercury (T-Hg) in hair and MeHg in blood as biomarkers. Fish consumption was assessed using a food frequency questionnaire (FFQ), including detailed information about consumption of different fish species, reflecting average intake during 1 year. We also determined inorganic mercury (I-Hg) in blood, and selenium (Se) in serum. The average total fish consumption, as reported in the food frequency questionnaire, was approximately 4 times/week (range 1.6-19 times/week). Fish species potentially high in MeHg, included in the Swedish dietary advisories, was consumed by 79% of the women. About 10% consumed such species more than once a week, i.e., more than what is recommended. Other fish species potentially high in MeHg, not included in the Swedish dietary advisories, was consumed by 54% of the women. Eleven percent never consumed fish species potentially high in MeHg. T-Hg in hair (median 0.70 mg/kg; range 0.08-6.6 mg/kg) was associated with MeHg in blood (median 1.7 {mu}g/L; range 0.30-14 {mu}g/L; r {sub s}=0.78; p<0.001). Hair T-Hg, blood MeHg and serum Se (median 70 {mu}g/L; range 46-154 {mu}g/L) increased with increasing total fish consumption (r {sub s}=0.32; p<0.001, r {sub s}=0.37; p<0.001 and r {sub s}=0.35; p=0.002, respectively). I-Hg in blood (median 0.24 {mu}g/L; range 0.01-1.6 {mu}g/L) increased with increasing number of dental amalgam fillings. We found no statistical significant associations between the various mercury species measured and the Se concentration in serum. Hair mercury levels exceeded the levels corresponding to the EPA reference dose (RfD) of 0.1 {mu}g MeHg/kg b.w. per day in 20% of the women. Thus, there seems to be no margin of safety for neurodevelopmental effects in fetus, for women with high fish consumption unless they decrease their intake of certain fish species.

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-30

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

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

    International Nuclear Information System (INIS)

    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 14 C end products of 14 CH 3 HgI demethylation. This method was used in conjuction with a 203 Hg 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

  12. Methyl mercury in terrestrial compartments

    International Nuclear Information System (INIS)

    Stoeppler, M.; Burow, M.; Padberg, S.; May, K.

    1993-09-01

    On the basis of the analytical methodology available at present the state of the art for the determination of total mercury and of various organometallic compounds of mercury in air, precipitation, limnic systems, soils, plants and biota is reviewed. This is followed by the presentation and discussion of examples for the data obtained hitherto for trace and ultratrace levels of total mercury and mainly methyl mercury in terrestrial and limnic environments as well as in biota. The data discussed stem predominantly from the past decade in which, due to significant methodological progress, many new aspects were elucidated. They include the most important results in this area achieved by the Research Centre (KFA) Juelich within the project 'Origin and Fate of Methyl Mercury' (contracts EV4V-0138-D and STEP-CT90-0057) supported by the Commission of the European Communities, Brussels. (orig.) [de

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  14. The influence of some thiols on biliary excretion of methyl mercury

    International Nuclear Information System (INIS)

    Refsvik, T.

    1983-01-01

    N-Acetylpenicillamine and thiola increased biliary excretion of methyl mercury and sulfhydryl right after administration. Cysteine increased excretion of methyl mercury in bile after a temporary decrease following administration. During the interval of decreased mercury excretion biliary excretion of cysteine passed through a maximum. This indicates the existence of a common factor of the excretory systems for cysteine and methyl mercury and illustrates that cysteine cannot carry methyl mercury from liver to bile. Relatively large proportions of unchanged thiola and N-acetylpenicillamine were excreted in bile. Bile collected after administration of one of these compounds, in addition to thiola or N-acetylpenicillamine, contained other methyl mercury carrying components not present in control bile. From the experiments undertaken it cannot be stated whether these components play any role in the increased excretion of methyl mercury in bile caused by thiola and N-acetylpenicillamine. The mechanisms of increased biliary excretion of methyl mercury following administration of N-acetylpenicillamine, thiola and cysteine are discussed. (author)

  15. The effect of selenium on the biliary excretion and organ distribution of mercury in the rat after exposure to methyl mercuric chloride

    International Nuclear Information System (INIS)

    Alexander, J.; Norseth, T.

    1979-01-01

    The influence of selenium compounds on the biliary excretion and the organ distribution of mercury after injection of methyl mercuric chloride(4μmol/kg) have been tested. Selenite, seleno-di-N-acetylglycine and seleno-methionine strongly inhibited the biliary excretion of mercury. Selenite even in a molar dose of 1/40 of the methyl mercury dose inhibited the biliary excretion of mercury. The loss toxic seleno-di-N-acetylglycine was needed in larger molar doses and did not act as rapidly as selenite. Biliary excreted methyl mercury is known to be partly reabsorbed in the gut. Subsequently a part of it is deposited in the kidneys since drainage of the bile lowered the kidney content of mercury. Rats given selenium compounds in combination with bile drainage showed further reduction of the kidney mercury content than bile duct drainage alone. Thus the demonstrated lowering effect of selenium compounds on the kidney mercury content cannot be completely explained by an inhibition of biliary excretion of mercury. The mercury concentration in the brain was increased by the selenium compounds; the effect being dependent of the selenium dose reaching a maximum at an equimolar selenite - to methyl mercury dose ratio. The mechanisms by which selenium influences the methyl mercury kinetics are discussed. (author)

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

    Science.gov (United States)

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

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

    Science.gov (United States)

    Wells, Ellen M; Herbstman, Julie B; Lin, Yu Hong; Hibbeln, Joseph R; Halden, Rolf U; Witter, Frank R; Goldman, Lynn R

    2017-04-01

    Prior studies addressing associations between mercury and blood pressure have produced inconsistent findings; some of this may result from measuring total instead of speciated mercury. This cross-sectional study of 263 pregnant women assessed total mercury, speciated mercury, selenium, and n-3 polyunsaturated fatty acids in umbilical cord blood and blood pressure during labor and delivery. Models with a) total mercury or b) methyl and inorganic mercury were evaluated. Regression models adjusted for maternal age, race/ethnicity, prepregnancy body mass index, neighborhood income, parity, smoking, n-3 fatty acids and selenium. Geometric mean total, methyl, and inorganic mercury concentrations were 1.40µg/L (95% confidence interval: 1.29, 1.52); 0.95µg/L (0.84, 1.07); and 0.13µg/L (0.10, 0.17), respectively. Elevated systolic BP, diastolic BP, and pulse pressure were found, respectively, in 11.4%, 6.8%, and 19.8% of mothers. In adjusted multivariable models, a one-tertile increase of methyl mercury was associated with 2.83mmHg (0.17, 5.50) higher systolic blood pressure and 2.99mmHg (0.91, 5.08) higher pulse pressure. In the same models, an increase of one tertile of inorganic mercury was associated with -1.18mmHg (-3.72, 1.35) lower systolic blood pressure and -2.51mmHg (-4.49, -0.53) lower pulse pressure. No associations were observed with diastolic pressure. There was a non-significant trend of higher total mercury with higher systolic blood pressure. We observed a significant association of higher methyl mercury with higher systolic and pulse pressure, yet higher inorganic mercury was significantly associated with lower pulse pressure. These results should be confirmed with larger, longitudinal studies. Copyright © 2017 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

    Harmon, S.M.

    2003-01-01

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

  19. Mercury contamination and exposure assessment of fishery products in Korea.

    Science.gov (United States)

    Yang, Hye-Ran; Kim, Na-Young; Hwang, Lae-Hong; Park, Ju-Sung; Kim, Jung-Hun

    2015-01-01

    In this study, total (T-Hg) and methyl mercury (Me-Hg) contamination was investigated in fishery products including canned fish, fish sauces, dried bonito and frozen tuna sashimi, collected from retail markets in Korea, to assess dietary exposure. Direct mercury analyser and gas chromatography-electron captured detector were employed to measure T-Hg and Me-Hg, respectively. The highest T-Hg and Me-Hg contamination was present in tuna sashimi, followed by dried bonito, respectively. Canned tuna showed more frequent detection and higher content than other canned fishery products. The weekly exposure estimate indicates that exposure to mercury from fishery products is safe, showing 2.59% provisional tolerable weekly intake (PTWI) for T-Hg, 1.82% PTWI for Me-Hg and 4.16% reference dose for Me-Hg. However, it should be addressed to monitor the mercury contamination in fish and fishery products regularly, to safeguard vulnerable population such as children, to limit intake of these food products.

  20. Environmental Influences on the Epigenome: Exposure- Associated DNA Methylation in Human Populations.

    Science.gov (United States)

    Martin, Elizabeth M; Fry, Rebecca C

    2018-04-01

    DNA methylation is the most well studied of the epigenetic regulators in relation to environmental exposures. To date, numerous studies have detailed the manner by which DNA methylation is influenced by the environment, resulting in altered global and gene-specific DNA methylation. These studies have focused on prenatal, early-life, and adult exposure scenarios. The present review summarizes currently available literature that demonstrates a relationship between DNA methylation and environmental exposures. It includes studies on aflatoxin B 1 , air pollution, arsenic, bisphenol A, cadmium, chromium, lead, mercury, polycyclic aromatic hydrocarbons, persistent organic pollutants, tobacco smoke, and nutritional factors. It also addresses gaps in the literature and future directions for research. These gaps include studies of mixtures, sexual dimorphisms with respect to environmentally associated methylation changes, tissue specificity, and temporal stability of the methylation marks.

  1. Vertical Distribution of Total Mercury and Mercury Methylation in a Landfill Site in Japan

    Directory of Open Access Journals (Sweden)

    Jing Yang

    2018-06-01

    Full Text Available Mercury is a neurotoxin, with certain organic forms of the element being particularly harmful to humans. The Minamata Convention was adopted to reduce the intentional use and emission of mercury. Because mercury is an element, it cannot be decomposed. Mercury-containing products and mercury used for various processes will eventually enter the waste stream, and landfill sites will become a mercury sink. While landfill sites can be a source of mercury pollution, the behavior of mercury in solid waste within a landfill site is still not fully understood. The purpose of this study was to determine the depth profile of mercury, the levels of methyl mercury (MeHg, and the factors controlling methylation in an old landfill site that received waste for over 30 years. Three sampling cores were selected, and boring sampling was conducted to a maximum depth of 18 m, which reached the bottom layer of the landfill. Total mercury (THg and MeHg were measured in the samples to determine the characteristics of mercury at different depths. Bacterial species were identified by 16S rRNA amplification and sequencing, because the methylation process is promoted by a series of genes. It was found that the THg concentration was 19–975 ng/g, with a geometric mean of 298 ng/g, which was slightly less than the 400 ng/g concentration recorded 30 years previously. In some samples, MeHg accounted for up to 15–20% of THg, which is far greater than the general level in soils and sediments, although the source of MeHg was unclear. The genetic data indicated that hgcA was present mostly in the upper and lower layers of the three cores, merA was almost as much as hgcA, while the level of merB was hundreds of times less than those of the other two genes. A significant correlation was found between THg and MeHg, as well as between MeHg and MeHg/THg. In addition, a negative correlation was found between THg and merA. The coexistence of the three genes indicated that both

  2. Distribution and excretion of methyl and phenyl mercury salts

    Energy Technology Data Exchange (ETDEWEB)

    Gage, J C

    1964-01-01

    The distribution, metabolism, and excretion of phenyl mercury acetate (P.M.A.) and of methyl mercury dicyanidiamide (M.M.D.) has been studied in the rat during the repeated subcutaneous administration of small doses over a period of six weeks, and for several weeks after a single dose. The results indicate that P.M.A. is absorbed unchanged into the circulation from which it is mainly removed by the liver and kidneys where it is metabolized and excreted in the feces and urine mostly as inorganic mercury. During repeated dosage the rats reached a steady state by the end of the second week when excretion approximately balanced intake. No measurable amount of mercury was found in the central nervous system. After repeated dosage with M.M.D. there is no clear indication of a steady state being reached after six weeks. There is an accumulation of organic mercury in all tissues, particularly in the red cells, and a progressive increase in the brain concentration. M.M.D. is more slowly released from the tissues than P.M.A. and the breakdown to inorganic mercury is low. The control of human exposure to alkyl and aryl mercury salts is considered in the light of these experimental observations. The recommendation that the concentration of alkyl mercury salts in the atmosphere should not exceed 0-01 mg/m/sup 3/ seems justifiable, but there appears to be no reason to establish the figure for aryl mercury salts below the 0-1 mg/m/sup 3/ recommended for inorganic mercury vapor. 13 references, 4 tables.

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  4. Efficiency of solvent extraction methods for the determination of methyl mercury in forest soils

    Energy Technology Data Exchange (ETDEWEB)

    Qian, J. [Department of Forest Ecology, Swedish University of Agricultural Sciences, Umeaa (Sweden); Dept. of Analytical Chemistry, Umeaa Univ. (Sweden); Skyllberg, U. [Department of Forest Ecology, Swedish University of Agricultural Sciences, Umeaa (Sweden); Tu, Q.; Frech, W. [Dept. of Analytical Chemistry, Umeaa Univ. (Sweden); Bleam, W.F. [Dept. of Soil Science, University of Wisconsin, Madison, WI (United States)

    2000-07-01

    Methyl mercury was determined by gas chromatography, microwave induced plasma, atomic emission spectrometry (GC-MIP-AES) using two different methods. One was based on extraction of mercury species into toluene, pre-concentration by evaporation and butylation of methyl mercury with a Grignard reagent followed by determination. With the other, methyl mercury was extracted into dichloromethane and back extracted into water followed by in situ ethylation, collection of ethylated mercury species on Tenax and determination. The accuracy of the entire procedure based on butylation was validated for the individual steps involved in the method. Methyl mercury added to various types of soil samples showed an overall average recovery of 87.5%. Reduced recovery was only caused by losses of methyl mercury during extraction into toluene and during pre-concentration by evaporation. The extraction of methyl mercury added to the soil was therefore quantitative. Since it is not possible to directly determine the extraction efficiency of incipient methyl mercury, the extraction efficiency of total mercury with an acidified solution containing CuSO{sub 4} and KBr was compared with high-pressure microwave acid digestion. The solvent extraction efficiency was 93%. For the IAEA 356 sediment certified reference material, mercury was less efficiently extracted and determined methyl mercury concentrations were below the certified value. Incomplete extraction could be explained by the presence of a large part of inorganic sulfides, as determined by x-ray absorption near-edge structure spectroscopy (XANES). Analyses of sediment reference material CRM 580 gave results in agreement with the certified value. The butylation method gave a detection limit for methyl mercury of 0.1 ng g{sup -1}, calculated as three times the standard deviation for repeated analysis of soil samples. Lower values were obtained with the ethylation method. The precision, expressed as RSD for concentrations 20 times

  5. Mercury methylation and bacterial activity associated to tropical phytoplankton

    International Nuclear Information System (INIS)

    Coelho-Souza, Sergio A.; Guimaraes, Jean R.D.; Mauro, Jane B.N.; Miranda, Marcio R.; Azevedo, Sandra M.F.O.

    2006-01-01

    The methylated form of mercury (Hg), methylmercury (MeHg), is one of the most toxic pollutants. Biotic and/or abiotic methylation, often associated to sulfate-reducing bacteria metabolism, occurs in aquatic environments and in many tropical areas, mostly in the periphyton associated to floating macrophyte roots. Data about mercury methylation by phytoplankton are scarce and the aim of this study was to verify the biotic influence in the methylation process in Microcystis aeruginosa and Sineccocystis sp. laboratory strains and in natural populations of phytoplankton from two different aquatic systems, the mesotrophic Ribeirao das Lajes reservoir and hypereutrophic oligohaline Jacarepagua lagoon, Rio de Janeiro state, Brazil. Adapted radiochemical techniques were used to measure sulfate-reduction, mercury methylation and bacterial activity in phytoplankton samples. Methyl- 203 Hg formation from added inorganic 203 Hg and 3 H-Leucine uptake were measured by liquid scintillation as well as sulfate-reduction, estimated as H 2 35 S produced from added Na 2 35 SO 4 . There was no significant difference in low methylation potentials (0.37%) among the two cyanobacterium species studied in laboratory conditions. At Ribeirao das Lajes reservoir, there was no significant difference in methylation, bacterial activity and sulfate-reduction of surface sediment between the sampling points. Methylation in sediments (3-4%) was higher than in phytoplankton (1.5%), the opposite being true for bacterial activity (sediment mean 6.6 against 150.3 nmol gdw -1 h -1 for phytoplankton samples). At Jacarepagua lagoon, an expressive bacterial activity (477.1 x 10 3 nmol gdw -1 h -1 at a concentration of 1000 nM leucine) and sulfate-reduction (∼21% H 2 35 S trapped) associated to phytoplankton (mostly cyanobacteria M. aeruginosa) was observed, but mercury methylation was not detected

  6. Mercury methylation and bacterial activity associated to tropical phytoplankton

    Energy Technology Data Exchange (ETDEWEB)

    Coelho-Souza, Sergio A. [Laboratorio de Tracadores Wolfgang Pfeiffer, SL 62, Instituto de Biofisica Carlos Chagas Filho, Bloco G, Ilha do Fundao, Universidade Federal do Rio de Janeiro (IBCCF/UFRJ), RJ, CEP 21949-900 (Brazil); Guimaraes, Jean R.D. [Laboratorio de Tracadores Wolfgang Pfeiffer, SL 62, Instituto de Biofisica Carlos Chagas Filho, Bloco G, Ilha do Fundao, Universidade Federal do Rio de Janeiro (IBCCF/UFRJ), RJ, CEP 21949-900 (Brazil)]. E-mail: jeanrdg@biof.ufrj.br; Mauro, Jane B.N. [Laboratorio de Tracadores Wolfgang Pfeiffer, SL 62, Instituto de Biofisica Carlos Chagas Filho, Bloco G, Ilha do Fundao, Universidade Federal do Rio de Janeiro (IBCCF/UFRJ), RJ, CEP 21949-900 (Brazil); Miranda, Marcio R. [Laboratorio de Tracadores Wolfgang Pfeiffer, SL 62, Instituto de Biofisica Carlos Chagas Filho, Bloco G, Ilha do Fundao, Universidade Federal do Rio de Janeiro (IBCCF/UFRJ), RJ, CEP 21949-900 (Brazil); Azevedo, Sandra M.F.O. [Laboratorio de Ecofisiologia e Toxicologia de Cianobacterias, IBCCF/UFRJ, RJ (Brazil)

    2006-07-01

    The methylated form of mercury (Hg), methylmercury (MeHg), is one of the most toxic pollutants. Biotic and/or abiotic methylation, often associated to sulfate-reducing bacteria metabolism, occurs in aquatic environments and in many tropical areas, mostly in the periphyton associated to floating macrophyte roots. Data about mercury methylation by phytoplankton are scarce and the aim of this study was to verify the biotic influence in the methylation process in Microcystis aeruginosa and Sineccocystis sp. laboratory strains and in natural populations of phytoplankton from two different aquatic systems, the mesotrophic Ribeirao das Lajes reservoir and hypereutrophic oligohaline Jacarepagua lagoon, Rio de Janeiro state, Brazil. Adapted radiochemical techniques were used to measure sulfate-reduction, mercury methylation and bacterial activity in phytoplankton samples. Methyl-{sup 203}Hg formation from added inorganic {sup 203}Hg and {sup 3}H-Leucine uptake were measured by liquid scintillation as well as sulfate-reduction, estimated as H{sub 2} {sup 35}S produced from added Na{sub 2} {sup 35}SO{sub 4}. There was no significant difference in low methylation potentials (0.37%) among the two cyanobacterium species studied in laboratory conditions. At Ribeirao das Lajes reservoir, there was no significant difference in methylation, bacterial activity and sulfate-reduction of surface sediment between the sampling points. Methylation in sediments (3-4%) was higher than in phytoplankton (1.5%), the opposite being true for bacterial activity (sediment mean 6.6 against 150.3 nmol gdw{sup -1} h{sup -1} for phytoplankton samples). At Jacarepagua lagoon, an expressive bacterial activity (477.1 x 10{sup 3} nmol gdw{sup -1} h{sup -1} at a concentration of 1000 nM leucine) and sulfate-reduction ({approx}21% H{sub 2} {sup 35}S trapped) associated to phytoplankton (mostly cyanobacteria M. aeruginosa) was observed, but mercury methylation was not detected.

  7. Mercury Quick Facts: Health Effects of Mercury Exposure

    Science.gov (United States)

    ... 2012 What are the Health Effects of Mercury Exposure? The health effects that can be caused by breathing mercury depend ... they breathe faster and have smaller lungs. Health effects caused by long-term exposure to mercury vapors • • Anxiety • • Excessive shyness • • Anorexia • • Sleeping ...

  8. Methyl Mercury Production In Tropical Hydromorphic Soils: Impact Of Gold Mining.

    Science.gov (United States)

    Guedron, S.; Charlet, L.; Harris, J.; Grimaldi, M.; Cossa, D.

    2007-12-01

    Artisanal alluvial gold mining is important in many tropical developing countries and several million people are involved worldwide. The dominant use of mercury for gold amalgamation in this activity leads to mercury accumulation in soils, to sediment contamination and to methyl mercury (MMHg) bioaccumulation along the food chain. In this presentation we will present recent data on methyl mercury production in hydromorphic soils and tailing ponds from a former gold mining area located in French Guiana (South America). Comparison of specific fluxes between a pristine sub watershed and the contaminated watershed shows that former mining activities lead to a large enhancement of dissolved and particulate MMHg emissions at least by a factor of 4 and 6, respectively. MMHg production was identified in sediments from tailing ponds and in surrounding hydromorphic soils. Moreover, interstitial soil water and tailing pond water profiles sampled in an experimental tailing pond demonstrate the presence of a large MMHg production in the suboxic areas. Both tailing ponds and hydromorphic soils present geochemical conditions that are favorable to bacterial mercury methylation (high soil Hg content, high aqueous ferric iron and dissolved organic carbon concentrations). Although sulfate-reducing bacteria have been described as being the principal mercury methylating bacteria, the positive correlation between dissolved MMHg and ferrous iron concentrations argue for a significant role of iron-reducing bacteria. Identifications by sequencing fragments of 16S rRNA from total soil DNA support these interpretations. This study demonstrates that current and past artisanal gold mining in the tropics lead to methyl mercury production in contaminated areas. As artisanal activities are increasing with increasing gold prices, the bio- magnification of methyl mercury in fish presents an increasing threat to local populations whose diet relies on fish consumption.

  9. Mercury Exposure and Heart Diseases

    Science.gov (United States)

    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

  10. Mercury Exposure and Heart Diseases.

    Science.gov (United States)

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

    2017-01-12

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

  11. Mercury Exposure and Heart Diseases

    Directory of Open Access Journals (Sweden)

    Giuseppe Genchi

    2017-01-01

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

  12. Prenatal mercury exposure, maternal seafood consumption and associations with child language at five years.

    Science.gov (United States)

    Vejrup, Kristine; Brandlistuen, Ragnhild Eek; Brantsæter, Anne Lise; Knutsen, Helle Katrine; Caspersen, Ida Henriette; Alexander, Jan; Lundh, Thomas; Meltzer, Helle Margrete; Magnus, Per; Haugen, Margaretha

    2018-01-01

    Methyl mercury (MeHg) is a well-known neurotoxin and evidence suggests that also low level exposure may affect prenatal neurodevelopment. Uncertainty exists as to whether the maternal MeHg burden in Norway might affect child neurodevelopment. To evaluate the association between prenatal mercury exposure, maternal seafood consumption and child language and communication skills at age five. The study sample comprised 38,581 mother-child pairs in the Norwegian Mother and Child Cohort Study. Maternal mercury blood concentration in gestational week 17 was analysed in a sub-sample of 2239 women. Prenatal mercury exposure from maternal diet was calculated from a validated FFQ answered in mid-pregnancy. Mothers reported children's language and communications skills at age five by a questionnaire including questions from the Ages and Stages Questionnaire (ASQ), the Speech and Language Assessment Scale (SLAS) and the Twenty Statements about Language-Related Difficulties (language 20). We performed linear regression analyses adjusting for maternal characteristics, nutritional status and socioeconomic factors. Median maternal blood mercury concentration was 1.03μg/L, dietary mercury exposure was 0.15μg/kgbw/wk, and seafood intake was 217g/wk. Blood mercury concentrations were not associated with any language and communication scales. Increased dietary mercury exposure was significantly associated with improved SLAS scores when mothers had a seafood intake below 400g/wk in the adjusted analysis. Sibling matched analysis showed a small significant adverse association between those above the 90th percentile dietary mercury exposure and the SLAS scores. Maternal seafood intake during pregnancy was positively associated with the language and communication scales. Low levels of prenatal mercury exposure were positively associated with language and communication skills at five years. However, the matched sibling analyses suggested an adverse association between mercury and child

  13. Oxidative stress and repetitive element methylation changes in artisanal gold miners occupationally exposed to mercury

    Directory of Open Access Journals (Sweden)

    Diana M. Narváez

    2017-09-01

    Full Text Available Mercury (Hg exposure is a public health concern due to its persistence in the environment and its high toxicity. Such toxicity has been associated with the generation of oxidative stress in occupationally exposed subjects, such as artisanal gold miners. In this study, we characterize occupational exposure to Hg by measuring blood, urine and hair levels, and investigate oxidative stress and DNA methylation associated with gold mining. To do this, samples from 53 miners and 36 controls were assessed. We show higher levels of oxidative stress marker 8-OHdG in the miners. Differences in LINE1 and Alu(Yb8 DNA methylation between gold miners and control group are present in peripheral blood leukocytes. LINE1 methylation is positively correlated with 8-OHdG levels, while XRCC1 and LINE1 methylation are positively correlated with Hg levels. These results suggest an effect of Hg on oxidative stress and DNA methylation in gold miners that may have an impact on miners’ health.

  14. Practical isolation of methyl mercury in natural waters

    International Nuclear Information System (INIS)

    Schintu, M.; Kauri, T.; Contu, A.; Kudo, A.

    1987-01-01

    A simple method to isolate both organic and inorganic mercury in natural waters is described. The mercuric compounds were quantitatively extracted with dithizone from six different kinds of water spiked at nanogram levels with radioactive mercuric chloride and methylmercuric chloride. After the separation from the inorganic mercury with sodium nitrite, methyl mercury was transferred to aqueous medium with sodium thiosulfate. The method provides a high recovery of organic as well as inorganic mercury to an aqueous medium, prior to their determination by gold-trap cold vapor atomic absorption spectrophotometry. This method is easy, rapid, and inexpensive. Furthermore, the limited number of analytical steps should reduce loss and contamination

  15. METHYL MERCURY IN GREEN MUSCLE (Mytilus viridis L. FROM FISH MARKET MUARA ANGKE : BEFORE AND AFTER COOKING

    Directory of Open Access Journals (Sweden)

    Ermin K. Winarno

    2010-06-01

    Full Text Available The determination of methyl mercury content in green muscle (Mytilus viridis L. that were taken from Pasar Pelelangan Ikan Muara Angke, Jakarta Bay has been carried out. Sampling was taken in November 2005 and March 2006, the samples were bought from the green muscle sellers. The aim of this research is to know the effect of cooking on the content of methyl mercury in green muscle. Samples were homogenized, weighed and washed with aceton and toluene. After washing, the homogenized material was added with HCl solution, extracted with toluene, then the methyl mercury content in toluene extract was analyzed using gas chromatography. The results of this research showed that methyl mercury concentration in raw and cooked green muscle respectively were 0.803 + 0.019 mg/g and 0.443 + 0.035 mg/g (in November 2005 and 0.096 + 0.014 mg/g and 0.079 + 0.016 mg/g (in March 2006 respectively. The methyl mercury content in raw (in November 2005 was higher than in cooked green muscle as permitted concentration in the sea biota by WHO and FAO, it is 0.5 ppm (mg/g, on the other hand the result of the second sampling in March 2006 showed that methyl mercury content in green muscle was lower than permitted concentration. Cooking process of the green muscle decreased methyl mercury content 44.85% (sampling in November 2005 and 17.71% (sampling in March 2006, because methyl mercury that bonded to protein were distributed to boiling water. Methyl mercury content in green muscle after cooking was still lower than the permitted concentration.   Keywords: methyl mercury, green muscle, Mytilus viridis L., Muara Angke

  16. Possible interferences of mercury sulfur compounds with ethylated and methylated mercury species using HPLC-ICP-MS

    International Nuclear Information System (INIS)

    Wilken, R.D.; Nitschke, F.; Falter, R.

    2003-01-01

    The HPLC-ICP-MS coupling technique is able to separate and detect methyl, ethyl and inorganic mercury isotopes specifically. An identification of ethyl mercury(+) is not possible when the widely used sodium tetraethylborate derivatisation method in combination with GC-AFS/AAS or ICP-MS techniques is performed because it contains ethyl groups. An unidentified compound with the same retention time as ethyl mercury was found in the HPLC chromatograms of industrial sewage samples and humic-rich soils of microcosm experiments after applying water vapour distillation. We also observed such unidentified peaks in samples of heavily contaminated sites in Eastern Germany, separated by HPLC fractionation only. In the experiments described, different mercury sulfur adducts were synthesised and tested for their retention times in the HPLC-ICP-MS system. It was found that the compound CH 3 -S-Hg + showed the same retention time as the ethyl mercury standard. It is therefore possible that ethyl mercury detected in chromatography by comparison of the retention time could also be due to an adduct of a sulfur compound and a mercury species. CH 3 -S-Hg + should be tested in other chromatographic mercury speciation methods for this effect. This work can also be regarded as a contribution to the discussion of artificially occurring methyl mercury in sediments during sample preparation. (orig.)

  17. Health Effects of Exposures to Mercury

    Science.gov (United States)

    ... IRIS database Top of Page Elemental (Metallic) Mercury Effects Exposures to metallic mercury most often occur when metallic ... poor performance on tests of mental function Higher exposures may also cause kidney effects, respiratory failure and death. Note that metallic mercury ...

  18. Does mercury vapor exposure increase urinary selenium excretion

    Energy Technology Data Exchange (ETDEWEB)

    Hongo, T; Suzuki, T; Himeno, S; Watanabe, C; Satoh, H; Shimada, Y

    1985-01-01

    It has been reported that an increase of urinary selenium excretion may occur as a result of mercury vapor exposure. However, experimental data regarding the interaction between mercury vapor and selenium have yielded ambiguous results about the retention and elimination of selenium due to mercury vapor exposure and the decrease of selenium excretion due to mercury in the form of mercuric mercury (Hg/sup 2 +/). In this study, the authors measured urinary mercury and selenium in workers with or without exposure to mercury vapor to determine whether or not urinary selenium excretion was increased as a result of mercury vapor exposure. Urine samples were collected from 141 workers, 71 men and 70 women, whose extent of exposure to mercury vapor varied according to their job sites. Workers were divided into five groups according to their urinary mercury levels. The mercury level in group I was less than 2.8 nmol/mmol creatinine which means that this group was mostly free from mercury exposure. The average age was almost identical among the groups. For both sexes, group V (with the highest urinary mercury level) had the lowest urinary selenium level, but one-way variance analysis (ANOVA) did not reveal any significant variations of urinary selenium with urinary mercury levels; however, a weak but significant negative correlation between mercury and selenium was found in men.

  19. Mercury methylation coupled to iron reduction by dissimilatory iron-reducing bacteria.

    Science.gov (United States)

    Si, Youbin; Zou, Yan; Liu, Xiaohong; Si, Xiongyuan; Mao, Jingdong

    2015-03-01

    Iron reduction and mercury methylation by dissimilatory iron-reducing bacteria (DIRB), Geobacter sulfurreducens and Shewanella oneidensis, were studied, and the relationship of mercury methylation coupled to iron reduction was determined. The ability of both bacteria for reducing iron was tested, and Fe(III) reduction occurred with the highest rate when ferric oxyhydroxide was used as a terminal electron acceptor. G. sulfurreducens had proven to mediate the production of methylmercury (MeHg), and a notable increase of MeHg following the addition of inorganic Hg was observed. When the initial concentration of HgCl2 was 500nM, about 177.03nM of MeHg was determined at 8d after G. sulfurreducens inoculation. S. oneidensis was tested negligible for Hg methylation and only 12.06nM of MeHg was determined. Iron reduction could potentially influence Hg methylation rates. The increase in MeHg was consistent with high rate of iron reduction, indicating that Fe(III) reduction stimulated the formation of MeHg. Furthermore, the net MeHg concentration increased at low Fe(III) additions from 1.78 to 3.57mM, and then decreased when the added Fe(III) was high from 7.14 to 17.85mM. The mercury methylation rate was suppressed with high Fe(III) additions, which might have been attributable to mercury complexation and low availability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Methylation of mercury in isopod Porcellio scaber

    International Nuclear Information System (INIS)

    Jereb, V.; Horvat, M.; Cerne, I.; Drobne, D.

    2002-01-01

    Due to some remarkable characteristics, more than a decade ago terrestrial isopods were introduced as biornonitoring organisms for metals in industrially polluted environments. These characteristics are: suitable size, abundance, ease of handling in the laboratory, the ability to accumulate metals (Zn, Cd, Pb) and dose-dependent response to different metals and pesticides (diazinon). The isopod Porcellio scaber is a small terrestrial crab, which colonizes upper soil layers and litter. It lives in a humid environment, mostly under tree-leaves, decaying wood and bigger stones. It is an omnivore, but its most common food is decomposing organic matter. Therefore, isopods are important for decomposition and cycling of mineral matter in nature. Porcellio scaber can be also found on the river banks of river ldrijca a mercury contaminated site, but there is a lack of data on effects of Hg on Porcellio scaber. Therefore, it would be of interest to investigate the biological cycle of mercury in this animal. The objectives of our work were: To assess the magnitudes of biological processes (metal Hg 2+ ) uptake, its retention in the animal, accumulation in glands, excretion of Hg by faeces); To investigate the possibility of mercury transformation in the animal (Hg 2+→ MeHg + ). It is known, that intestine is a possible Hg 2+ methylation site; in the gut of Porcellio scaber are present anaerobes and very likely also sulphate-reducing bacteria, which are known to be responsible for Hg 2+ methylation in nature; To validate an appropriate analytical technique for Hg 2+ methylation assays in the isopod Porcellio scaber

  1. Biological methylation of inorganic mercury by Saccharomyces cerevisiae - a possible environmental process

    International Nuclear Information System (INIS)

    Reisinger, K.; Stoeppler, M.; Nuernberg, H.W.

    1983-01-01

    The biological methylation of inorganic mercury by S-adenosylmethione (SAM) was investigated by incubation experiments with Saccharomyces cerevisae (''bakers' yeast''). The methyl donor (methionine) and the acceptor (Hg 2+ as HgCl 2 ) were also applied in their labelled form (double labelling). Methylmercury as a result of a possibly biological methyl group transfer could not be detected. As reaction product only small amounts (0.01per mille yield) of elemental mercury (Hg 0 ) were found, while the overwhelming amount of HgCl 2 had not reacted. (orig.) [de

  2. Total mercury, methyl mercury, and carbon in fresh and burned plants and soil in Northwestern Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Mailman, M. [Department of Zoology, University of Manitoba, Winnipeg, Man. R3T 2N2 (Canada); Freshwater Institute, 501 University Crescent, Winnipeg, Man. R3T 2N6 (Canada)]. E-mail: mailmanma@dfo-mpo.gc.ca; Bodaly, R.A. [Department of Zoology, University of Manitoba, Winnipeg, Man. R3T 2N2 (Canada); Freshwater Institute, 501 University Crescent, Winnipeg, Man. R3T 2N6 (Canada)

    2005-11-15

    Terrestrial plants and soil contain substantial amounts of organic carbon (C) and mercury. Flooding terrestrial areas stimulates microbial methyl mercury (MeHg) production and fish obtain elevated MeHg concentrations. Our purpose was to determine the loss of C, total mercury (THg), and MeHg from boreal plants and soil after burning to assess the potential of burning before flooding to lower MeHg. Fresh plants contained 4 to 52 ng g{sup -1} dry weight (dw) of THg and 0.1 to 1.3 ng g{sup -1} dw of MeHg. Upland soils contained 162{+-}132 ng g{sup -1} dw of THg and 0.6{+-}0.6 ng g{sup -1} dw of MeHg. Complete burning caused plants to lose 96, 98, 97, and 94% of the mass, C, THg, and MeHg, respectively. Upland soil lost 27, 95, 79, and 82% of the mass, C, THg, and MeHg, respectively. Our results demonstrated that a substantial loss of C, THg, and MeHg was caused by burning. - Burning terrestrial vegetation and soil causes substantial losses of organic carbon, total mercury, and methyl mercury.

  3. Total mercury, methyl mercury, and carbon in fresh and burned plants and soil in Northwestern Ontario

    International Nuclear Information System (INIS)

    Mailman, M.; Bodaly, R.A.

    2005-01-01

    Terrestrial plants and soil contain substantial amounts of organic carbon (C) and mercury. Flooding terrestrial areas stimulates microbial methyl mercury (MeHg) production and fish obtain elevated MeHg concentrations. Our purpose was to determine the loss of C, total mercury (THg), and MeHg from boreal plants and soil after burning to assess the potential of burning before flooding to lower MeHg. Fresh plants contained 4 to 52 ng g -1 dry weight (dw) of THg and 0.1 to 1.3 ng g -1 dw of MeHg. Upland soils contained 162±132 ng g -1 dw of THg and 0.6±0.6 ng g -1 dw of MeHg. Complete burning caused plants to lose 96, 98, 97, and 94% of the mass, C, THg, and MeHg, respectively. Upland soil lost 27, 95, 79, and 82% of the mass, C, THg, and MeHg, respectively. Our results demonstrated that a substantial loss of C, THg, and MeHg was caused by burning. - Burning terrestrial vegetation and soil causes substantial losses of organic carbon, total mercury, and methyl mercury

  4. Development of a single-meal fish consumption advisory for methyl mercury

    Energy Technology Data Exchange (ETDEWEB)

    Ginsberg, G.L.; Toal, B.F.

    2000-02-01

    Methyl mercury (meHg) contamination of fish is the leading cause of fish consumption advisories in the US. These advisories have focused upon repeated or chronic exposure, whereas risks during pregnancy may also exist from a single-meal exposure if the fish tissue concentration is high enough. In this study, acute exposure to meHg from a single fish meal was analyzed by using the one-compartment meHg biokinetic model to predict maternal hair concentrations. These concentrations were evaluated against the mercury hair concentration corresponding to the US Environmental Protection Agency's reference dose (RfD), which is intended to protect against neurodevelopmental effects. The one-compartment model was validated against blood concentrations from three datasets in which human subjects ingested meHg in fish, either as a single meal or multiple meals. Model simulations of the single-meal scenario at different fish meHg concentrations found that concentrations of 2.0 ppm or higher can be associated with maternal hair concentrations elevated above the RfD level for days to weeks during gestation. A single-meal fish concentration cutoff of {ge} 2.0 ppm is an important consideration, especially because this single high exposure event might be in addition to a baseline meHg body burden from other types of fish consumption. This type of single-meal advisory requires that fish sampling programs provide data for individual rather than composited fish, and take into account seasonal differences that may exist in fish concentrations.

  5. Sexual differences in the distribution and retention of organic and inorganic mercury in methyl mercury-treated rats

    International Nuclear Information System (INIS)

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

    1986-01-01

    At 56 days of age, male and female Long-Evans rats received 1 μmole of 203 Hg-labeled mercuric chloride per kilogram sc and total, organic, and inorganic mercury contents and concentrations in tissues were determined for up to 98 days postdosing. When expressed on a concentration basis, the only significant sexual difference was in the higher average concentration of organic mercury in the kidneys of females. When expressed on a tissue content basis, significant male-female differences in the kinetics (sex x time interactions) of organic mercury retention were found in kidney, brain, skeletal muscle, pelt, and whole body. Significant sex x time interactions in the concentrations of organic mercury were found in kidney, skeletal muscle, and whole body. Kinetics of retention and concentration of inorganic Hg in the pelt differed significantly for males and females. Discordance of degree of statistical significance of differences in mercury contents and concentrations reflected in part differences in relative body composition of males and females. Differences in integrated exposure were estimated by the female-to-male ratio of areas under retention curves. Reconstruction of whole body organic and inorganic mercury burdens from constituent tissues indicated that integrated exposures of males and females to inorganic mercury were equal but females had a lower integrated exposure to organic mercury. Integrated exposure of liver to either form of mercury was about equal in males and females. However, the integrated exposure of the brain of females to inorganic mercury was 2.19 times that of males suggest'ing a sexual difference in accumulation or retention of inorganic mercury in the nervous system

  6. Isoproterenol potentiation of methyl mercury effects in vivo cardiac ATPasees and 3H-dopamine uptake

    International Nuclear Information System (INIS)

    Ahammad-Sahib, K.I.; Moorthy, K.S.; Cameron, J.A.; Desaiah, D.

    1988-01-01

    Isoproterenol, a potent B-adrenergic receptor agonist, has been known to produce infarct-like myocardial lesions in rats characterized by swelling of endoplasmic reticulum. The swelling of this system is interpreted as an influx of large amount of extracellular fluid into myocardial cells by disturbances of the electrolyte metabolism. Isoproterenol is employed clinically as a bronchodilator in respiratory disorders and as a stimulant in heart block and cardiogenic shocks. In spite of its clinical use, possible drug-chemical interactions leading to adverse health effects are obvious when individuals on a regular isoproterenol treatment are exposed to an environmental contaminant such as methyl mercury. Consumption of fish and fish products is by far the most significant route of exposure to environmental mercury. In spite of such a possibility, little is know about isoproterenol-methyl mercury interaction. The present study forms the first of this kind to report such interactions and their effects on cardiac membrane bound enzymes such as Na + -K + and Ca 2+ -ATPases. Since Na + -K + ATPase has been implicated in uptake and release processes of catecholamines, the effects were also studied on 3 H-dopamine uptake by sarcoplasmic reticulum. As a prelude to these proposed long-term chronic studies with non-lethal doses in the present report only single and sub-lethal doses were used for a shorter (48h) duration

  7. METHYL MERCURY PRODUCTION IN NATURAL-COLLECTED SEDIMENT WITH DIFFERENT GEOCHEMICAL PARAMETERS

    Directory of Open Access Journals (Sweden)

    Markus T. Lasut

    2010-06-01

    Full Text Available Production of methyl mercury (MeHg has been shown in laboratory experiments using mercuric chloride (HgCl2 compound released into natural-collected sediments with different geochemical conditions. While the HgCl2 concentration was 30 µl of 113 ppm of HgCl2, the geochemical conditions [pH, salinity, total organic content (TOC, sulfur] of sampled sediments were A: 8.20, 0.00 ppt, 1.97%, and 0.92 ppt, respectively; B: 7.90, 2.00 ppt, 4.69%, and 1.98 ppt, respectively; and C: 8.20, 24.00 ppt, 1.32 %, and 90.90 ppt, respectively. A control was set with no HgCl2. Samples and control were incubated in room temperature of 27 ± 1 °C. Observations were done along 9 days with interval of 3 days. While total Hg was measured using mercury analyzer with Cold Vapor-Atomic Absorbtion Spectrophometer (CV-AAS system, MeHg was measured by using a gas chromatograph with ECD detector after extracted by dithizone-sodium sulfide extraction method. The result shows that MeHg was found in both treatment and control experiments. The concentrations of the MeHg varied according to the geochemical condition of the sampled sediments. Peak production of MeHg occurred on the third day; however, the production was not significantly affected by the incubation time. Optimum production was found inversely related to the pH, in which highest and lowest the pH formed an ineffectively methylated mercury species. The TOC was significantly correlated to the optimum production. Salinity and sulfate contents were found not correlated to the optimum of MeHg production.   Keywords: Methyl mercury; methylation process; sediment; biogeochemistry

  8. Postnatal exposure to methyl mercury from fish consumption: a review and new data from the Seychelles Child Development Study.

    Science.gov (United States)

    Myers, Gary J; Thurston, Sally W; Pearson, Alexander T; Davidson, Philip W; Cox, Christopher; Shamlaye, Conrad F; Cernichiari, Elsa; Clarkson, Thomas W

    2009-05-01

    Fish is an important source of nutrition worldwide. Fish contain both the neurotoxin methyl mercury (MeHg) and nutrients important for brain development. The developing brain appears to be most sensitive to MeHg toxicity and mothers who consume fish during pregnancy expose their fetus prenatally. Although brain development is most dramatic during fetal life, it continues for years postnatally and additional exposure can occur when a mother breast feeds or the child consumes fish. This raises the possibility that MeHg might influence brain development after birth and thus adversely affect children's developmental outcomes. We reviewed postnatal MeHg exposure and the associations that have been published to determine the issues associated with it and then carried out a series of analyses involving alternative metrics of postnatal MeHg exposure in the Seychelles Child Development Study (SCDS) Main Cohort. The SCDS is a prospective longitudinal evaluation of prenatal MeHg exposure from fish consumption. The Main Cohort includes 779 subjects on whom recent postnatal exposure data were collected at the 6-, 19-, 29-, 66-, and 107-month evaluations. We examined the association of recent postnatal MeHg exposure with multiple 66- and 107-month outcomes and then used three types of alternative postnatal exposure metrics to examine their association with the children's intelligence quotient (IQ) at 107 months of age. Recent postnatal exposure at 107 months of age was adversely associated with four endpoints, three in females only. One alternative postnatal metric was beneficially associated with 9-year IQ in males only. We found several associations between postnatal MeHg biomarkers and children's developmental endpoints. However, as has been the case with prenatal MeHg exposure in the SCDS Main Cohort study, no consistent pattern of associations emerged to support a causal relationship.

  9. Phytoremediation of Ionic and Methyl Mercury Pollution

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, Richard B.

    2005-06-01

    control the chemical speciation, electrochemical state, transport, and aboveground binding of mercury in order to manage this toxicant. To advance this mercury phytoremediation strategy, our planned research focuses on the following Specific Aims: (1) to increase the transport of mercury to aboveground tissue; (2) to identify small mercury binding peptides that enhance hyperaccumulation aboveground; (3) to test the ability of multiple genes acting together to enhance resistance and hyperaccumulation; (4) to construct a simple molecular system for creating male/female sterility, allowing engineered grass, shrub, and tree species to be released indefinitely at contaminated sites; (5) to test the ability of transgenic cottonwood and rice plants to detoxify ionic mercury and prevent methylmercury release from contaminated sediment; and (6) to initiate field testing with transgenic cottonwood and rice for the remediation of methylmercury and ionic mercury. The results of these experiments will enable the phytoremediation of methyl- and ionic mercury by a wide spectrum of deep-rooted, fast-growing plants adapted to diverse environments. We have made significant progress on all six of these specific aims as summarized below.

  10. Use of implantable pellets to administer low levels of methyl mercury to fish

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, B.S.; Jagoe, C.H.; Gross, T.S.

    1999-07-01

    Implantable pellets of methyl mercury chloride were tested in Nile Tilapia (oreochromis niloticus) to appraise the effectiveness of the method for chronic studies of mercury. Two dosing regimes of 15 and 1.5 grams/CH{sub 3}HgCl pellet (test 1) and 1 and 0.1 grams/pellet (tests 2--3) of methyl mercury chloride were used in three tests. Additional pellets containing only matrix were used as controls. The pellets were inserted into the peritoneal cavity along with a microchip for identification. Three methods of incision closure: sutures and two types of surgical glue, were tested. Pellets used in test one released the dose too fast, resulting in premature death of the fish. Results from tests 2 and 3 show blood mercury concentrations over time and tissue levels at necropsy consistent with dose suggestion that this is a viable method of dosing fish.

  11. Mercury Exposure and Heart Rate Variability: A Systematic Review

    Science.gov (United States)

    Gribble, Matthew O.; Cheng, Alan; Berger, Ronald D.; Rosman, Lori; Guallar, Eliseo

    2015-01-01

    Background Mercury affects the nervous system and has been implicated in altering heart rhythm and function. We sought to better define its role in modulating heart rate variability, a well-known marker of cardiac autonomic function. Design Systematic review. Methods We searched PubMed, Embase, TOXLINE and DART databases without language restriction. We report findings as a qualitative systematic review because heterogeneity in study design and assessment of exposures and outcomes across studies, as well as other methodological limitations of the literature, precluded a quantitative meta-analysis. Results We identified 12 studies of mercury exposure and heart rate variability in human populations (10 studies involving primarily environmental methylmercury exposure and two studies involving occupational exposure to inorganic mercury) conducted in Japan, the Faroe Islands, Canada, Korea, French Polynesia, Finland and Egypt. The association of prenatal mercury exposure with lower high-frequency band scores (thought to reflect parasympathetic activity) in several studies, in particular the inverse association of cord blood mercury levels with the coefficient of variation of the R-R intervals and with low frequency and high frequency bands at 14 years of age in the Faroe Islands birth cohort study, suggests that early mercury exposure could have a long-lasting effect on cardiac parasympathetic activity. Studies with later environmental exposures to mercury in children or in adults were heterogeneous and did not show consistent associations. Conclusions The evidence was too limited to draw firm causal inferences. Additional research is needed to elucidate the effects of mercury on cardiac autonomic function, particularly as early-life exposures might have lasting impacts on cardiac parasympathetic function. PMID:26231507

  12. Electrochemical reduction of imazamethabenz methyl on mercury and carbon electrodes

    International Nuclear Information System (INIS)

    Ruiz Montoya, Mercedes; Pintado, Sara; Rodriguez Mellado, Jose Miguel

    2010-01-01

    This paper presents polarographic and voltammetric studies of the reduction of the herbicide imazamethabenz methyl (2/3-methyl-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate), on mercury and carbon electrodes. The electrochemical studies were performed in strongly acidic media (0.1-2.7 M H 2 SO 4 ) as well as in the pH range of 1-12. The overall reduction process involves the uptake of two electrons. The results obtained in polarography show that there is the reduction of two species, related via an acid-base equilibrium, and having very close reduction potentials. The voltammetric results obtained with a glassy carbon electrode were very similar to those observed on mercury electrodes. The reducible group in the molecule is the imidazolinone ring. In strongly acidic media (pH a ), the reaction mechanism proposed is the reduction of the protonated herbicide by an electrochemical-chemical-electrochemical (ECE) process, being the r.d.s. the second electron transfer. At pH > pK a the neutral form of the herbicide is reduced and the second electron transfer becomes reversible or quasi-reversible. In basic media, the species reduced is the deprotonated imazamethabenz methyl and the r.d.s. is the second electron transfer.

  13. Electrochemical reduction of imazamethabenz methyl on mercury and carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Montoya, Mercedes, E-mail: mmontoya@uhu.e [Departamento de Ingenieria Quimica, Quimica Fisica y Quimica Organica, Universidad de Huelva, Campus El Carmen, Facultad de Ciencias Experimentales, E-21071 Huelva (Spain); Pintado, Sara; Rodriguez Mellado, Jose Miguel [Departamento de Quimica Fisica y Termodinamica Aplicada, Universidad de Cordoba, Campus Universitario de Rabanales, edificio ' Marie Curie' , E-14014 Cordoba (Spain)

    2010-03-30

    This paper presents polarographic and voltammetric studies of the reduction of the herbicide imazamethabenz methyl (2/3-methyl-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate), on mercury and carbon electrodes. The electrochemical studies were performed in strongly acidic media (0.1-2.7 M H{sub 2}SO{sub 4}) as well as in the pH range of 1-12. The overall reduction process involves the uptake of two electrons. The results obtained in polarography show that there is the reduction of two species, related via an acid-base equilibrium, and having very close reduction potentials. The voltammetric results obtained with a glassy carbon electrode were very similar to those observed on mercury electrodes. The reducible group in the molecule is the imidazolinone ring. In strongly acidic media (pH < pK{sub a}), the reaction mechanism proposed is the reduction of the protonated herbicide by an electrochemical-chemical-electrochemical (ECE) process, being the r.d.s. the second electron transfer. At pH > pK{sub a} the neutral form of the herbicide is reduced and the second electron transfer becomes reversible or quasi-reversible. In basic media, the species reduced is the deprotonated imazamethabenz methyl and the r.d.s. is the second electron transfer.

  14. [Toxic nephropathy secondary to occupational exposure to metallic mercury].

    Science.gov (United States)

    Voitzuk, Ana; Greco, Vanina; Caputo, Daniel; Alvarez, Estela

    2014-01-01

    Toxic nephrophaties secondary to occupational exposure to metals have been widely studied, including membranous nephropathy by mercury, which is rare. Occupational poisoning by mercury is frequent, neurological symptoms are the main form of clinical presentation. Secondary renal involvement in chronic exposure to metallic mercury can cause glomerular disease by deposit of immune-complexes. Membranous glomerulopathy and minimal change disease are the most frequently reported forms. Here we describe the case of a patient with occupational exposure to metallic mercury, where nephrotic syndrome due to membranous glomerulonephritis responded favorably to both chelation and immunosuppressive therapy.

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

    Science.gov (United States)

    Zheng, Wei

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

    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. (orig.)

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zizek, Suzana; Horvat, Milena [Jozef Stefan Institute, Department of Environmental Sciences, Ljubljana (Slovenia); Ribeiro Guevara, Sergio [Centro Atomico Bariloche, Laboratorio de Analisis por Activacion Neutronica, Bariloche (Argentina)

    2008-04-15

    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 {sup 197}Hg. The benefit of using this tracer is its high specific activity, which enables spikes as low as 0.02 ng Hg{sup 2+} g{sup -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{sup 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{sup -1} of sediment slurry) resulted in MeHg formation between 0.01 and 0.1 ng MeHg g{sup -1} in Podroteja and Kozarska Grapa. Higher spikes resulted in slightly elevated MeHg production (up to a maximum of 0.27 ng g{sup -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

  19. A Review of Mercury Exposure and Health of Dental Personnel

    Directory of Open Access Journals (Sweden)

    Natasha Nagpal

    2017-03-01

    Full Text Available Considerable effort has been made to address the issue of occupational health and environmental exposure to mercury. This review reports on the current literature of mercury exposure and health impacts on dental personnel. Citations were searched using four comprehensive electronic databases for articles published between 2002 and 2015. All original articles that evaluated an association between the use of dental amalgam and occupational mercury exposure in dental personnel were included. Fifteen publications from nine different countries met the selection criteria. The design and quality of the studies showed significant variation, particularly in the choice of biomarkers as an indicator of mercury exposure. In several countries, dental personnel had higher mercury levels in biological fluids and tissues than in control groups; some work practices increased mercury exposure but the exposure levels remained below recommended guidelines. Dental personnel reported more health conditions, often involving the central nervous system, than the control groups. Clinical symptoms reported by dental professionals may be associated with low-level, long-term exposure to occupational mercury, but may also be due to the effects of aging, occupational overuse, and stress. It is important that dental personnel, researchers, and educators continue to encourage and monitor good work practices by dental professionals.

  20. Assessing elemental mercury vapor exposure from cultural and religious practices.

    Science.gov (United States)

    Riley, D M; Newby, C A; Leal-Almeraz, T O; Thomas, V M

    2001-08-01

    Use of elemental mercury in certain cultural and religious practices can cause high exposures to mercury vapor. Uses include sprinkling mercury on the floor of a home or car, burning it in a candle, and mixing it with perfume. Some uses can produce indoor air mercury concentrations one or two orders of magnitude above occupational exposure limits. Exposures resulting from other uses, such as infrequent use of a small bead of mercury, could be well below currently recognized risk levels. Metallic mercury is available at almost all of the 15 botanicas visited in New York, New Jersey, and Pennsylvania, but botanica personnel often deny having mercury for sale when approached by outsiders to these religious and cultural traditions. Actions by public health authorities have driven the mercury trade underground in some locations. Interviews indicate that mercury users are aware that mercury is hazardous, but are not aware of the inhalation exposure risk. We argue against a crackdown by health authorities because it could drive the practices further underground, because high-risk practices may be rare, and because uninformed government intervention could have unfortunate political and civic side effects for some Caribbean and Latin American immigrant groups. We recommend an outreach and education program involving religious and community leaders, botanica personnel, and other mercury users.

  1. Association of methionine requirement with methyl mercury resistant mutants of yeast

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A.; Sherman, F.

    1974-01-25

    It has been known for several years that strains resistant to mercury can be obtained in several bacterial species. Soon after the correlation between resistance to antibiotics and to mercury was recognized, it was established that genetic elements conferring resistance to antibiotics, mercury and other heavy metals in Escherichia coli and Samonella typhimurium and Staphylococcus aureus reside on extrachromosomal resistance transfer factors or plasmids. Among fungi, mercury resistant strains of Botrytis cinerea, Penicillium notatum, Sclerotinia fructicola, Stemphylium sarcinaeforme, and Saccharomyces cerevisiae have been reported. In most cases, this was accomplished by training the normal strains for growth on media supplemented with successively increasing concentrations of mercury compounds, and in some cases the resistance was lost when subcultured on mercury-free media. It is noteworthy that in none of the mercury-adapted strains of fungi has the genetic basis of resistance been determined. In this report we describe a method of isolation and characterization of methyl mercury resistant mutants of S. cerevisiae. This study was undertaken with the view that the examination of physiological changes associated with genetically defined resistant mutants will be useful in studying the mechanisms of cellular detoxification of organic mercurials.

  2. The price of gold: mercury exposure in the Amazonian rain forest.

    Science.gov (United States)

    Branches, F J; Erickson, T B; Aks, S E; Hryhorczuk, D O

    1993-01-01

    Concern has surfaced over the recent discovery of human mercury exposure throughout the tropical rain forest of South America's Amazon River Basin. The probable source of mercury has been traced to gold mines located within the interior. The mining process involves the extraction of gold from ore by burning off a mercury additive, resulting in vaporization of elemental mercury into the surrounding environment. The purpose of this case series is to document mercury levels in miners and local villagers presenting with a history of exposure, or signs and symptoms consistent with mercury toxicity. Over a five year period (1986-91), the whole blood and urine mercury levels of 55 Brazilian patients demonstrating signs and symptoms consistent with mercury exposure were collected. Thirty-three (60%) of the subjects had direct occupational exposure to mercury via gold mining and refining. Whole blood mercury levels ranged from 0.4-13.0 micrograms/dL (mean 3.05 micrograms/dL). Spot urine levels ranged 0-151 micrograms/L (mean = 32.7 micrograms/L). Occupational mercury exposure is occurring in the Amazon River Basin. Interventions aimed at altering the gold mining process while protecting the workers and surrounding villagers from the source of exposure are essential. The impact of the gold mining industry on general environmental contamination has not been investigated.

  3. Mercury exposure in young children living in New York City.

    Science.gov (United States)

    Rogers, Helen S; Jeffery, Nancy; Kieszak, Stephanie; Fritz, Pat; Spliethoff, Henry; Palmer, Christopher D; Parsons, Patrick J; Kass, Daniel E; Caldwell, Kathy; Eadon, George; Rubin, Carol

    2008-01-01

    Residential exposure to vapor from current or previous cultural use of mercury could harm children living in rental (apartment) homes. That concern prompted the following agencies to conduct a study to assess pediatric mercury exposure in New York City communities by measuring urine mercury levels: New York City Department of Health and Mental Hygiene's (NYCDOHMH) Bureau of Environmental Surveillance and Policy, New York State Department of Health/Center for Environmental Health (NYSDOHCEH), Wadsworth Center's Biomonitoring Program/Trace Elements Laboratory (WC-TEL), and Centers for Disease Control and Prevention (CDC). A previous study indicated that people could obtain mercury for ritualistic use from botanicas located in Brooklyn, Manhattan, and the Bronx. Working closely with local community partners, we concentrated our recruiting efforts through health clinics located in potentially affected neighborhoods. We developed posters to advertise the study, conducted active outreach through local partners, and, as compensation for participation in the study, we offered a food gift certificate redeemable at a local grocer. We collected 460 urine specimens and analyzed them for total mercury. Overall, geometric mean urine total mercury was 0.31 microg mercury/l urine. One sample was 24 microg mercury/l urine, which exceeded the (20 microg mercury/l urine) NYSDOH Heavy Metal Registry reporting threshold for urine mercury exposure. Geometric mean urine mercury levels were uniformly low and did not differ by neighborhood or with any clinical significance by children's ethnicity. Few parents reported the presence of mercury at home, in a charm, or other item (e.g., skin-lightening creams and soaps), and we found no association between these potential sources of exposure and a child's urinary mercury levels. All pediatric mercury levels measured in this study were well below a level considered to be of medical concern. This study found neither self-reported nor measured

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

    DEFF Research Database (Denmark)

    Baatrup, E; Danscher, G

    1988-01-01

    and the selected organs were determined by measuring the uptake of 203Hg-labeled MeHg. Spleen, liver, and kidney had the highest concentrations after both experimental periods, while the largest relative increases were found in brain, muscle, and kidney. The subcellular distribution of mercury accumulations...... was demonstrated cytochemically in liver and kidney using the silver enhancement method by which accumulations of mercury-sulfides and/or mercury-selenides are made visible for light and electron microscopy. When sections prepared from the liver and kidney from fish, injected with selenium 2 hr prior to being...... pronounced in the kidney. The HgSe pool, supposed to represent methyl mercury, was shown by the presence of silver deposits at new locations as well as by an increase in the amount of deposits within lysosomes. The new locations included (1) secretory-like vesicles and the bile canaliculi of the liver...

  5. Investigating the Connection between hgcA and Mercury Methylation Rates in the Environment

    Science.gov (United States)

    King, A. J.; Christensen, G. A.; Wymore, A. M.; Podar, M.; Hurt, R. A., Jr.; Brown, S. D.; Palumbo, A. V.; Bender, K. S.; Fields, M. W.; Gilmour, C. C.; Santillan, E. F. U.; Brandt, C. C.; Elias, D. A.

    2015-12-01

    Methylmercury (MeHg) is a common contaminant in many natural environments and is known to be a neurotoxin that impacts human health through bioaccumulation in food webs. The anaerobic conversion of mercury (Hg) to MeHg by microorganisms requires the presence of both HgcA and HgcB. In an effort to link hgcAB abundance and diversity with MeHg generation rates, we performed metagenomic and 16S rRNA sequencing as well as qualitative polymerase chain reaction (qPCR) of hgcA on samples from eight mercury-contaminated sites ranging from tidal marshes to Arctic permafrost. Custom algorithms were developed to filter hgcA sequences from the metagenomes, and to then select for those lineages that also contained hgcB. In the metagenomes, the Deltaproteobacteria dominated the pool of hgcAB from all eight sites; however, Firmicutes and methanogenic Archaea were each 50% less abundant. In parallel to the metagenomics studies, clone libraries of hgcAB were constructed for each site. This more cost-effective approach allowed us to verify the identity of the hgcAB+ organism, and yielded similar results to the metagenomes. Additionally, to determine the accuracy of our new degenerate qPCR primer sets (three sets specific to the three major clades of mercury methylators) in the environment, qPCR hgcA abundance values were compared to those derived from the metagenomes. Finally, we present evidence that hgcA abundance can correlate with MeHg concentrations but that the relationship is influenced by local environmental conditions. Our work demonstrates the relative efficacy of genetic methods for assessing the presence of mercury-methylators in eight different environments contaminated with mercury as well as the strength of association between abundance of hgcA and the rate of mercury methylation.

  6. Biomarkers of mercury exposure in two eastern Ukraine cities

    Science.gov (United States)

    Gibb, H.; Haver, C.; Kozlov, K.; Centeno, J.A.; Jurgenson, V.; Kolker, A.; Conko, K.M.; Landa, E.R.; Xu, H.

    2011-01-01

    This study evaluates biomarkers of mercury exposure among residents of Horlivka, a city in eastern Ukraine located in an area with geologic and industrial sources of environmental mercury, and residents of Artemivsk, a nearby comparison city outside the mercury-enriched area. Samples of urine, blood, hair, and nails were collected from study participants, and a questionnaire was administered to obtain data on age, gender, occupational history, smoking, alcohol consumption, fish consumption, tattoos, dental amalgams, home heating system, education, source of drinking water, and family employment in mines. Median biomarker mercury concentrations in Artemivsk were 0.26 ??g/g-Cr (urine), 0.92 ??g/L (blood), 0.42 ??g/g (hair), 0.11 ??g/g (toenails), and 0.09 ??g/g (fingernails); median concentrations in Horlivka were 0.15 ??g/g-Cr (urine), 1.01 ??g/L (blood), 0.14 ??g/g (hair), 0.31 ??g/g (toenails), and 0.31 ??g/g (fingernails). Biomarkers of mercury exposure for study participants from Horlivka and Artemivsk are low in comparison with occupationally exposed workers at a mercury recycling facility in Horlivka and in comparison with exposures known to be associated with clinical effects. Blood and urinary mercury did not suggest a higher mercury exposure among Horlivka residents as compared with Artemivsk; however, three individuals living in the immediate vicinity of the mercury mines had elevated blood and urinary mercury, relative to overall results for either city. For a limited number of residents from Horlivka (N = 7) and Artemivsk (N = 4), environmental samples (vacuum cleaner dust, dust wipes, soil) were collected from their residences. Mercury concentrations in vacuum cleaner dust and soil were good predictors of blood and urinary mercury. Copyright ?? 2011 JOEH, LLC.

  7. Impacts of Mercury Exposure on Free-Ranging Post-Fledged Piscivorous Birds

    Science.gov (United States)

    Mercury is one of the priority pollutants of concern for several EPA programs, other federal agencies, and state governments. The concern is especially focused on methyl mercury because of its high toxicity and its propensity for extremely high bioaccumulation in aquatic food web...

  8. Biological effects of methyl and ethyl mercury compounds used as disinfectants for seed-grain on domestic and wild life

    Energy Technology Data Exchange (ETDEWEB)

    Tejning, S

    1971-01-01

    A short survey of the harmful effects of methyl and ethyl mercury on wild and domestic life and on man since the introduction of these compounds in plant protection is given. The biological effects of methyl mercury in birds are illustrated by experiments in hens concerning its accumulation in their organs and plumage, its elimination in eggs and excrements and its influence on the health of the birds, their laying habits and egg production including the occurrence of embryonic damages and the hatchability. Attention is drawn to the ability of methyl mercury to cause genetical disorders. 14 references, 1 figure, 1 table.

  9. Total and methyl mercury, moisture, and porosity in Lake Michigan surficial sediment

    Data.gov (United States)

    U.S. Environmental Protection Agency — Total and methyl mercury, moisture content (%), and porosity were measured in Lake Michigan sediment by the U.S. Environmental Protection Agency/Office of Research...

  10. Mercury exposure induces cytoskeleton disruption and loss of renal function through epigenetic modulation of MMP9 expression.

    Science.gov (United States)

    Khan, Hafizurrahman; Singh, Radha Dutt; Tiwari, Ratnakar; Gangopadhyay, Siddhartha; Roy, Somendu Kumar; Singh, Dhirendra; Srivastava, Vikas

    2017-07-01

    Mercury is one of the major heavy metal pollutants occurring in elemental, inorganic and organic forms. Due to ban on most inorganic mercury containing products, human exposure to mercury generally occurs as methylmercury (MeHg) by consumption of contaminated fish and other sea food. Animal and epidemiological studies indicate that MeHg affects neural and renal function. Our study is focused on nephrotoxic potential of MeHg. In this study, we have shown for the first time how MeHg could epigenetically modulate matrix metalloproteinase 9(MMP9) to promote nephrotoxicity using an animal model of sub chronic MeHg exposure. MeHg caused renal toxicity as was seen by increased levels of serum creatinine and expression of early nephrotoxicity markers (KIM-1, Clusterin, IP-10, and TIMP). MeHg exposure also correlated strongly with induction of MMP9 mRNA and protein in a dose dependent manner. Further, while induction of MMP9 promoted cytoskeleton disruption and loss of cell-cell adhesion (loss of F-actin, Vimentin and Fibronectin), inhibition of MMP9 was found to reduce these disruptions. Mechanistic studies by ChIP analysis showed that MeHg modulated MMP9 by promoting demethylation of its regulatory region to increase its expression. Bisulfite sequencing identified critical CpGs in the first exon of MMP9 which were demethylated following MeHg exposure. ChIP studies also showed loss of methyl binding protein, MeCP2 and transcription factor PEA3 at the demethylated site confirming decreased CpG methylation. Our studies thus show how MeHg could epigenetically modulate MMP9 to promote cytoskeleton disruption leading to loss of renal function. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Hg L3 XANES Study of Mercury Methylation in Shredded Eichhornia Crassipes

    International Nuclear Information System (INIS)

    Rajan, M.; Darrow, J.; Hua, M.; Barnett, B.; Mendoza, M.; Greenfield, B.K.; Andrews, J.C.

    2008-01-01

    Eichhornia crassipes (water hyacinth) is a non-native plant found in abundance in the Sacramento-San Joaquin River Delta (hereafter called Delta). This species has become a problem, clogging waterways and wetlands. Water hyacinth are also known to accumulate mercury. Recent attempts to curb its proliferation have included shredding with specialized boats. The purpose of this research is to better understand the ability of water hyacinth to phytoremediate mercury and to determine the effect of shredding and anoxic conditions on mercury speciation in plant tissue. In the field assessment, total mercury levels in sediment from the Dow Wetlands in the Delta were found to be 0.273 ± 0.070 ppm Hg, and levels in hyacinth roots and shoots from this site were 1.17 ± 0.08 ppm and 1.03 ± 0.52 ppm, respectively, indicating bioaccumulation of mercury. Plant samples collected at this site were also grown in nutrient solution with 1 ppm HgCl 2 under (1) aerobic conditions, (2) anaerobic conditions, and (3) with shredded plant material only. The greatest accumulation was found in the roots of whole plants. Plants grown in these conditions were also analyzed at Stanford Synchrotron Radiation Laboratory using Hg L 3 X-ray Absorption Near Edge Spectroscopy (XANES), a method to examine speciation that is element-specific and noninvasive. Least-squares fitting of the XANES data to methylated and inorganic mercury(II) model compounds revealed that in plants grown live and aerobically, 5 ± 3% of the mercury was in the form of methylmercury, in a form similar to methylmercury cysteine. This percentage increased to 16 ± 4% in live plants grown anaerobically and to 22 ± 6% in shredded anaerobic plants. We conclude that shredding of the hyacinth plants and, in fact, subjection of plants to anaerobic conditions (e.g., as in normal decay, or in crowded growth conditions) increases mercury methylation. Mechanical removal of the entire plant is significantly more expensive than shredding

  12. Impacts of Sublethal Mercury Exposure on Birds: A Detailed Review.

    Science.gov (United States)

    Whitney, Margaret C; Cristol, Daniel A

    Mercury is a ubiquitous environmental contaminant known to accumulate in, and negatively affect, fish-eating and oceanic bird species, and recently demonstrated to impact some terrestrial songbirds to a comparable extent. It can bioaccumulate to concentrations of >1 μg/g in tissues of prey organisms such as fish and insects. At high enough concentrations, exposure to mercury is lethal to birds. However, environmental exposures are usually far below the lethal concentrations established by dosing studies.The objective of this review is to better understand the effects of sublethal exposure to mercury in birds. We restricted our survey of the literature to studies with at least some exposures >5 μg/g. The majority of sublethal effects were subtle and some studies of similar endpoints reached different conclusions. Strong support exists in the literature for the conclusion that mercury exposure reduces reproductive output, compromises immune function, and causes avoidance of high-energy behaviors. For some endpoints, notably certain measures of reproductive success, endocrine and neurological function, and body condition, there is weak or contradictory evidence of adverse effects and further study is required. There was no evidence that environmentally relevant mercury exposure affects longevity, but several of the sublethal effects identified likely do result in fitness reductions that could adversely impact populations. Overall, 72% of field studies and 91% of laboratory studies found evidence of deleterious effects of mercury on some endpoint, and thus we can conclude that mercury is harmful to birds, and the many effects on reproduction indicate that bird population declines may already be resulting from environmental mercury pollution.

  13. Probabilistic mercury multimedia exposure assessment in small children and risk assessment.

    Science.gov (United States)

    Morisset, Typhaine; Ramirez-Martinez, Alejandra; Wesolek, Nathalie; Roudot, Alain-Claude

    2013-09-01

    Emissions of mercury in the environment have been decreasing for several years. However, mercury species are still found in different media (food, water, air and breast-milk). Due to mercury toxicity and typical behaviour in children, we have conducted a mercury exposure assessment in French babies, and small children aged 0 to 36months. Consumption and mercury concentration data were chosen for the exposure assessment. The Monte Carlo technique has been used to calculate the weekly exposure dose in order to integrate inter-individual variability and parameter uncertainty. Exposure values have been compared to toxicological reference values for health risk assessment. Inorganic mercury median exposure levels ranged from 0.160 to 1.649μg/kg of body weight per week (95th percentile (P95): 0.298-2.027µg/kg bw/week); elemental mercury median exposure level in children was 0.11ng/kg bw/week (P95: 28ng/kg bw/week); and methylmercury median exposure level ranged from 0.247 to 0.273µg/kg bw/week (P95: 0.425-0.463µg/kg bw/week). Only elemental mercury by inhalation route (indoor air) and methylmercury by ingestion (fish and breast-milk) seem to lead to a health risk in small children. These results confirm the importance of assessing total mercury concentration in media like breast-milk, indoor air and dust and methylmercury level in food, other than fish and seafood. In this way, informed monitoring plan and risk assessment in an at-risk sub-population can be set. © 2013 Elsevier Ltd. All rights reserved.

  14. Health and environmental impact of mercury in the Philippines using nuclear techniques. Highlights and achievements

    International Nuclear Information System (INIS)

    Cortes-Maramba, Nelia

    2002-01-01

    This is the first comprehensive health evaluation made by the Department of Health of the mining community's exposure to total and methyl mercury. Previous studies have mainly focused more on the health risks associated with occupational exposure to mercury. Other sources of mercury exposure such as diet and other environmental media was not investigated and the population studied did not include high risk groups such as pregnant women and children

  15. Influence of rice straw amendment on mercury methylation and nitrification in paddy soils

    International Nuclear Information System (INIS)

    Liu, Yu-Rong; Dong, Ji-Xin; Han, Li-Li; Zheng, Yuan-Ming; He, Ji-Zheng

    2016-01-01

    Currently, rice straw return in place of burning is becoming more intensive in China than observed previously. However, little is known on the effect of returned rice straw on mercury (Hg) methylation and microbial activity in contaminated paddy fields. Here, we conduct a microcosm experiment to evaluate the effect of rice straw amendment on the Hg methylation and potential nitrification in two paddy soils with distinct Hg levels. Our results show that amended rice straw enhanced Hg methylation for relatively high Hg content soil, but not for low Hg soil, spiking the same additional fresh Hg. methylmercury (MeHg) concentration was significantly correlated to the dissolved organic carbon (DOC) content and relative abundance of dominant microbes associated with Hg methylation. Similarly, amended rice straw was found to only enhance the potential nitrification rate in soil with relatively high Hg content. These findings provide evidence that amended rice straw differentially modulates Hg methylation and nitrification in Hg contaminated soils possibly resulting from different characteristics in the soil microbial community. This highlights that caution should be taken when returning rice straw to contaminated paddy fields, as this practice may increase the risk of more MeHg production. Main finding: Rice straw amendment enhanced both Hg methylation and nitrification potential in the relatively high, but not low, Hg soil. - Highlights: • Rice straw enhanced Hg methylation in relatively high Hg content paddy soils. • Microbial community directly correlated to the Hg methylation. • Mercury methylation in soils depend on Hg bioavailability and microbial activities. • Hg input affects microbial community associated with decomposition of rice straw.

  16. Study of the distribution of methyl mercury (203Hg) by whole body autoradiography of macaque monkeys (Macaca irus)

    International Nuclear Information System (INIS)

    Benard, Patrick; Burgat-Sacaze, Viviane; Rico, Andre; Braun, J.-P.; Eghbali, Behrokh

    1978-01-01

    The distribution of methyl-mercury labelled with mercury-203 has been studied in Monkeys by whole body autoradiography technique. The mercury is rapidly absorbed. It is localized in all the body and mainly in well defined areas of the central nervous-system [fr

  17. Mercury methylation rates of biofilm and plankton microorganisms from a hydroelectric reservoir in French Guiana.

    Science.gov (United States)

    Huguet, L; Castelle, S; Schäfer, J; Blanc, G; Maury-Brachet, R; Reynouard, C; Jorand, F

    2010-02-15

    The Petit-Saut ecosystem is a hydroelectric reservoir covering 365km(2) of flooded tropical forest. This reservoir and the Sinnamary Estuary downstream of the dam are subject to significant mercury methylation. The mercury methylation potential of plankton and biofilm microorganisms/components from different depths in the anoxic reservoir water column and from two different sites along the estuary was assessed. For this, reservoir water and samples of epiphytic biofilms from the trunk of a submerged tree in the anoxic water column and from submerged branches in the estuary were batch-incubated from 1h to 3 months with a nominal 1000ng/L spike of Hg(II) chloride enriched in (199)Hg. Methylation rates were determined for different reservoir and estuarine communities under natural nutrient (reservoir water, estuary freshwater) and artificial nutrient (culture medium) conditions. Methylation rates in reservoir water incubations were the highest with plankton microorganisms sampled at -9.5m depth (0.5%/d) without addition of biofilm components. Mercury methylation rates of incubated biofilm components were strongly enhanced by nutrient addition. The results suggested that plankton microorganisms strongly contribute to the total Hg methylation in the Petit-Saut reservoir and in the Sinnamary Estuary. Moreover, specific methylation efficiencies (%Me(199)Hg(net)/cell) suggested that plankton microorganisms could be more efficient methylating actors than biofilm consortia and that their methylation efficiency may be reduced in the presence of biofilm components. Extrapolation to the reservoir scale of the experimentally determined preliminary methylation efficiencies suggested that plankton microorganisms in the anoxic water column could produce up to 27mol MeHg/year. Taking into account that (i) demethylation probably occurs in the reservoir and (ii) that the presence of biofilm components may limit the methylation efficiency of plankton microorganisms, this result is

  18. Exposure of Small-Scale Gold Miners in Prestea to Mercury, Ghana, 2012.

    Science.gov (United States)

    Mensah, Ebenezer Kofi; Afari, Edwin; Wurapa, Frederick; Sackey, Samuel; Quainoo, Albert; Kenu, Ernest; Nyarko, Kofi Mensah

    2016-01-01

    Small-scale gold miners in Ghana have been using mercury to amalgamate gold for many years. Mercury is toxic even at low concentration. We assessed occupational exposure of small-scale gold miners to mercury in Prestea, a gold mining town in Ghana . We conducted a cross-sectional study in which we collected morning urine samples from 343 small-scale gold miners and tested for elemental mercury. Data on small-scale gold miner's socio-demographics, adverse health effects and occupational factors for mercury exposure were obtained and analyzed using SPSS Version 16 to determine frequency and percentage. Bivariate analysis was used to determine occupational factors associated with mercury exposure at 95% confidence level. The mean age of the small-scale gold miners was 29.5 ±9.6 years, and 323(94.20%) were males. One hundred and sixty (46.65%) of the small-scale gold miners had urine mercury above the recommended exposure limit (mercury exposure among those who have previously worked at other small-scale gold mines (χ 2 =4.96, p=0.03). The use of personal protective equipment among the small-scale gold miners was low. Retorts, which are globally recommended for burning amalgam, were not found at mining sites. A large proportion of small-scale gold miners in Prestea were having mercury exposure in excess of occupational exposure limits, and are at risk of experiencing adverse health related complications. Ghana Environmental Protection Agency should organize training for the miners.

  19. Mercury in breast milk - a health hazard for infants in gold mining areas?

    Science.gov (United States)

    Bose-O'Reilly, Stephan; Lettmeier, Beate; Roider, Gabriele; Siebert, Uwe; Drasch, Gustav

    2008-10-01

    Breast-feeding can be a source of mercury exposure for infants. The main concern up to now is methyl-mercury exposure of women at child-bearing age. Certain fish species have high levels of methyl-mercury leading to consumer's advisory guidelines in regard of fish consumption to protect infants from mercury exposure passing through breast milk. Little is known about the transfer of inorganic mercury passing through breast milk to infants. Epidemiological studies showed negative health effects of inorganic mercury in gold mining areas. Small-scale gold miners use mercury to extract the gold from the ore. Environmental and health assessments of gold mining areas in Indonesia, Tanzania and Zimbabwe showed a high exposure with inorganic mercury in these gold mining areas, and a negative health impact of the exposure to the miners and the communities. This paper reports about the analysis and the results of 46 breast milk samples collected from mercury-exposed mothers. The median level of 1.87mug/l is fairly high compared to other results from literature. Some breast milk samples showed very high levels of mercury (up to 149mug/l). Fourteen of the 46 breast milk samples exceed 4mug/l which is considered to be a "high" level. US EPA recommends a "Reference Dose" of 0.3mug inorganic mercury/kg body weight/day [United States Environmental Protection Agency, 1997. Volume V: Health Effects of Mercury and Mercury Compounds. Study Report EPA-452/R-97-007: US EPA]. Twenty-two of the 46 children from these gold mining areas had a higher calculated total mercury uptake. The highest calculated daily mercury uptake of 127mug exceeds by far the recommended maximum uptake of inorganic mercury. Further systematic research of mercury in breast milk from small-scale gold mining areas is needed to increase the knowledge about the bio-transfer of mercury from mercury vapour-exposed mothers passing through breast milk to the breast-fed infant.

  20. Insights into microbial communities involved in mercury methylation in the San Francisco Bay estuary

    Science.gov (United States)

    Machak, C.; Francis, C. A.

    2013-12-01

    San Francisco Bay (SFB) estuary is the largest estuary on the western coast of the United States, draining a watershed covering more than one third of the state of California. Mercury (Hg) contamination in SFB, as a result of gold and mercury mining in the Coast Range and Sierra Nevada region, has been observed for at least 150 years. Additional sources of Hg contamination to SFB come from active oil refineries, manufacturing, and wastewater treatment plants in the area. Concentrations of methylmercury in the sediment at the time of sample collection for the present study ranged from 0.011-3.88 μg/kg (dry weight). At some sites, the concentration exceeds wetland toxicity limits, posing a threat to the health of the ecosystem and potentially endangering humans that use the estuary for food and recreation. This study attempts to understand the factors that control the transformation of Hg to methylmercury by microorganisms in aquatic sediments, where the majority of Hg methylation is known to occur. Under anoxic conditions, some sulfate- and iron-reducing bacteria have the capacity to transform Hg into methylmercury. To better understand the microbial communities involved in Hg methylation, an extensive library of 16S rRNA sequences was generated (via Illumina sequencing) from sediment samples at 20 sites throughout the SFB estuary. In addition to genomic data, we have access to a massive database of geochemical measurements made by the SFB Regional Monitoring Program at the sampling locations. These measurements show that our sediment samples have varying methylmercury concentrations and span gradients in porewater sulfate and Fe(III), which are the two known alternative electron acceptors for mercury-methylating anaerobic bacteria. The sampling sites also span gradients in other geochemical factors known to influence microbial community composition (and potentially Hg mercury methylation), such as available organic carbon, pH, and salinity. We will present the

  1. Human mercury exposure associated with small-scale gold mining in Burkina Faso.

    Science.gov (United States)

    Tomicic, Catherine; Vernez, David; Belem, Tounaba; Berode, Michèle

    2011-06-01

    In Burkina Faso, gold ore is one of the main sources of income for an important part of the active population. Artisan gold miners use mercury in the extraction, a toxic metal whose human health risks are well known. The aim of the present study was to assess mercury exposure as well as to understand the exposure determinants of gold miners in Burkinabe small-scale mines. The examined gold miners' population on the different selected gold mining sites was composed by persons who were directly and indirectly related to gold mining activities. But measurement of urinary mercury was performed on workers most susceptible to be exposed to mercury. Thus, occupational exposure to mercury was evaluated among ninety-three workers belonging to eight different gold mining sites spread in six regions of Burkina Faso. Among others, work-related exposure determinants were taken into account for each person during urine sampling as for example amalgamating or heating mercury. All participants were medically examined by a local medical team in order to identify possible symptoms related to the toxic effect of mercury. Mercury levels were high, showing that 69% of the measurements exceeded the ACGIH (American Conference of Industrial Hygienists) biological exposure indice (BEI) of 35 μg per g of creatinine (μg/g-Cr) (prior to shift) while 16% even exceeded 350 μg/g-Cr. Basically, unspecific but also specific symptoms related to mercury toxicity could be underlined among the persons who were directly related to gold mining activities. Only one-third among the studied subpopulation reported about less than three symptoms possibly associated to mercury exposure and nearly half of them suffered from at least five of these symptoms. Ore washers were more involved in the direct handling of mercury while gold dealers in the final gold recovery activities. These differences may explain the overexposure observed in gold dealers and indicate that the refining process is the major source

  2. Occupational exposure to mercury. What is a safe level?

    OpenAIRE

    Moienafshari, R.; Bar-Oz, B.; Koren, G.

    1999-01-01

    QUESTION: One of my pregnant patients, a dental hygienist, uses mercury in her workplace, but appears to have no symptoms of mercury toxicity. She has heard that mercury might affect her fetus. What should I recommend to her? What is a safe level of mercury in the air for pregnant women? ANSWER: Testing for levels of mercury in whole blood and, preferably, urine is useful for confirming exposure. Currently, mercury vapour concentrations greater than 0.01 mg/m3 are considered unsafe. Also, wom...

  3. Mercury exposure in the freshwater tilapia Oreochromis niloticus

    Energy Technology Data Exchange (ETDEWEB)

    Wang Rui [Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong); Wong Minghung [Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University (Hong Kong); Wang Wenxiong, E-mail: wwang@ust.h [Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong)

    2010-08-15

    Mercury (Hg) can be strongly accumulated and biomagnified along aquatic food chain, but the exposure pathway remains little studied. In this study, we quantified the uptake and elimination of both inorganic mercury [as Hg(II)] and methylmercury (as MeHg) in an important farmed freshwater fish, the tilapia Oreochromis niloticus, using {sup 203}Hg radiotracer technique. The dissolved uptake rates of both mercury species increased linearly with Hg concentration (tested at ng/L levels), and the uptake rate constant of MeHg was 4 times higher than that of Hg(II). Dissolved uptake of mercury was highly dependent on the water pH and dissolved organic carbon concentration. The dietborne assimilation efficiency of MeHg was 3.7-7.2 times higher than that of Hg(II), while the efflux rate constant of MeHg was 7.1 times lower. The biokinetic modeling results showed that MeHg was the greater contributor to the overall mercury bioaccumulation and dietary exposure was the predominant pathway. - Trophic transfer was the predominant pathway for mercury accumulation in tilapia, and methylmercury was more important in contributing to Hg accumulation than Hg(II).

  4. Mercury exposure in the freshwater tilapia Oreochromis niloticus

    International Nuclear Information System (INIS)

    Wang Rui; Wong Minghung; Wang Wenxiong

    2010-01-01

    Mercury (Hg) can be strongly accumulated and biomagnified along aquatic food chain, but the exposure pathway remains little studied. In this study, we quantified the uptake and elimination of both inorganic mercury [as Hg(II)] and methylmercury (as MeHg) in an important farmed freshwater fish, the tilapia Oreochromis niloticus, using 203 Hg radiotracer technique. The dissolved uptake rates of both mercury species increased linearly with Hg concentration (tested at ng/L levels), and the uptake rate constant of MeHg was 4 times higher than that of Hg(II). Dissolved uptake of mercury was highly dependent on the water pH and dissolved organic carbon concentration. The dietborne assimilation efficiency of MeHg was 3.7-7.2 times higher than that of Hg(II), while the efflux rate constant of MeHg was 7.1 times lower. The biokinetic modeling results showed that MeHg was the greater contributor to the overall mercury bioaccumulation and dietary exposure was the predominant pathway. - Trophic transfer was the predominant pathway for mercury accumulation in tilapia, and methylmercury was more important in contributing to Hg accumulation than Hg(II).

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-08

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

  6. Novel methodology for the study of mercury methylation and reduction in sediments and water using 197Hg radiotracer

    International Nuclear Information System (INIS)

    Ribeiro Guevara, Sergio; Perez Catan, Soledad; Zizek, Suzana; Repinc, Urska; Jacimovic, Radojko; Horvat, Milena

    2007-01-01

    Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H 2 SO 4 or HCl were evaluated in freshwater sediments using 197 Hg radiotracer. Values obtained for the 197 Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of 197 Hg 2+ into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg 2+ contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg 2+ contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H 2 SO 4 method is recommended, since it is free from these interferences. 197 Hg radiotracer (T 1/2 = 2.673 d) has a production rate that is about 50 times higher than that of 203 Hg (T 1/2 46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to 203 Hg when it is used it in short-term experiments and produced by the irradiation of 196 Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the 196 Hg isotope is increased, the specific activity of the 197 Hg tracer can be significantly improved. In the present work, 197 Hg tracer was produced from mercury 51.58% enriched in the 196 Hg

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

    Science.gov (United States)

    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

  8. Photochemical reactions between mercury (Hg) and dissolved organic matter decrease Hg bioavailability and methylation.

    Science.gov (United States)

    Luo, Hong-Wei; Yin, Xiangping; Jubb, Aaron M; Chen, Hongmei; Lu, Xia; Zhang, Weihua; Lin, Hui; Yu, Han-Qing; Liang, Liyuan; Sheng, Guo-Ping; Gu, Baohua

    2017-01-01

    Atmospheric deposition of mercury (Hg) to surface water is one of the dominant sources of Hg in aquatic environments and ultimately drives methylmercury (MeHg) toxin accumulation in fish. It is known that freshly deposited Hg is more readily methylated by microorganisms than aged or preexisting Hg; however the underlying mechanism of this process is unclear. We report that Hg bioavailability is decreased by photochemical reactions between Hg and dissolved organic matter (DOM) in water. Photo-irradiation of Hg-DOM complexes results in loss of Sn(II)-reducible (i.e. reactive) Hg and up to an 80% decrease in MeHg production by the methylating bacterium Geobacter sulfurreducens PCA. Loss of reactive Hg proceeded at a faster rate with a decrease in the Hg to DOM ratio and is attributed to the possible formation of mercury sulfide (HgS). These results suggest a new pathway of abiotic photochemical formation of HgS in surface water and provide a mechanism whereby freshly deposited Hg is readily methylated but, over time, progressively becomes less available for microbial uptake and methylation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Mercury accumulation and its distribution to metallothionein in mouse brain after sub-chronic pulse exposure to mercury vapor

    Energy Technology Data Exchange (ETDEWEB)

    Yasutake, A. [Biochemistry Section, National Institute for Minamata Disease, Minamata, Kumamoto 867-0008 (Japan); Sawada, M.; Shimada, A. [Department of Veterinary Pathology, Tottori University, 4-101 Koyamacho, Minami, Tottori 680-0945 (Japan); Satoh, M. [Department of Hygienics, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585 (Japan); Tohyama, C. [Environmental Health Sciences Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan)

    2004-09-01

    Previously we found that exposure to mercury vapor effectively induced metallothionein (MT) biosynthesis in rat brain. Although the induction of not only MT-I/II but also MT-III was evident, the induction rate of the latter was much lower than that of the former. The brain of an MT-null mouse lacks MT-I/II, but has MT-III. Here we examined the effects of sub-chronic pulse exposure to mercury vapor on the brain MT in MT-null mice and their wild type controls. MT-null and wild type mice were preliminarily exposed to mercury vapor for 2 weeks at 0.1 mg Hg/m{sup 3} for 1 h/day for 3 days a week, and then exposed for 11 weeks at 4.1 mg Hg/m{sup 3} for 30 min/day for 3 days a week. This exposure caused no toxic signs such as abnormal behavior or loss of body weight gain in the mice of either strain throughout the experimental period. Twenty-four hours after the termination of the exposure, mice were sacrificed and brain samples were subjected to mercury analysis, MT assay, and pathological examination. The MT-null mice showed lower accumulation of mercury in the brain than the wild type mice. Mercury exposure resulted in a 70% increase of brain MT in the wild type mice, which was mostly accounted for by the increase in MT-I/II. On the other hand, the brain MT in the MT-null mice increased by 19%, suggesting less reactivity of the MT-III gene to mercury vapor. Although histochemical examination revealed silver-mercury grains in the cytoplasm of nerve cells and glial cells throughout the brains of both strains, no significant difference was observed between the two strains. (orig.)

  10. Urine mercury levels correlate with DNA methylation of imprinting gene H19 in the sperm of reproductive-aged men.

    Directory of Open Access Journals (Sweden)

    Zhaoxu Lu

    Full Text Available Mercury (Hg is a well-recognized environmental pollutant known by its toxicity of development and neurotoxicity, which results in adverse health outcomes. However, the mechanisms underlying the teratogenic effects of Hg are not well understood. Imprinting genes are emerging regulators for fetal development subjecting to environmental pollutants impacts. In this study, we examined the association between preconceptional Hg exposure and the alteration of DNA methylation of imprinting genes H19, Meg3, and Peg3 in human sperm DNA.A total of 616 men, aged from 22 to 59, were recruited from Reproductive Medicine Clinic of Maternal and Child Care Service Center and the Urologic Surgery Clinic of Shanxi Academy of Medical Sciences during April 2015 and March 2016. Demographic information was collected through questionnaires. Urine was collected and urinary Hg concentrations were measured using a fully-automatic double-channel hydride generation atomic fluorescence spectrometer. Methylation of imprinting genes H19, Meg3 and Peg3 of sperm DNA from 242 participants were examined by bisulfite pyrosequencing. Spearman's rank and multivariate regression analysis were used for correlation analysis between sperm DNA methylation status of imprinting genes and urinary Hg levels.The median concentration of Hg for 616 participants was 9.14μg/l (IQR: 5.56-12.52 μg/l; ranging 0.16-71.35μg/l. A total of 42.7% of the participants are beyond normal level for non-occupational exposure according to the criterion of Hg poisoning (≥10 μg/L. Spearman's rank analysis indicated a negative correlation between urinary Hg concentrations and average DNA methylation levels of imprinted genes H19 (rs = -0.346, p <0.05, but there was no such a correlation for Peg3 and Meg3. Further, we analyzed the correlation between methylation level at individual CpG site of H19 and urinary Hg level. The results showed a negative correlation between urinary Hg concentrations and three out of

  11. Evaluation of CP sil 8 film thickness for the capillary GC analysis of methyl mercury

    DEFF Research Database (Denmark)

    Petersen, Jens Højslev; Drabæk, Iver

    1992-01-01

    Different commercially available CP-Sil 8 CB capillary columns have been tested with a mixed standard containing methyl mercury chloride, ethyl mercury chloride and a stable nonpolar chlorinated hydrocarbon. The aim of the study was to see whether the columns tested could be used without special...... available insert for on-column injections on wide bore columns, and a 5.35 mum thick stationary phase. It was concluded that this CP Sil 8 CB column gave good results although minor interactions between the organo-mercury compounds and the column could be seen....

  12. Effect of environmental exposure to mercury on the functioning of the human body

    Directory of Open Access Journals (Sweden)

    Maciej Cyran

    2013-09-01

    Full Text Available Mercury is classified as a heavy metal and thus is commonly referred to as a death metal due to its high toxicity. In the environment it occurs in metallic form or in combination with other compounds. Amidst the sources of exposure to mercury, the most important environmental sources are dental amalgam and mercury vapor from the production of chlorine which is the most important source of occupational exposure. Mercury is easily soluble in fats, so it penetrates through biological membranes. Both - acute and chronic mercury poisoning causes characteristic clinical symptoms. There are several connections between exposure to this metal and toxic effects on the nervous system, cardiovascular system, endocrine system and kidneys. Thus mercury damages the structure of many organs and impairs their function

  13. Biomarkers of mercury exposure at a mercury recycling facility in Ukraine

    Science.gov (United States)

    Gibb, H.J.; Kozlov, K.; Buckley, J.P.; Centeno, J.; Jurgenson, V.; Kolker, A.; Conko, K.; Landa, E.; Panov, B.; Panov, Y.; Xu, H.

    2008-01-01

    This study evaluates biomarkers of occupational mercury exposure among workers at a mercury recycling operation in Gorlovka, Ukraine. The 29 study participants were divided into three occupational categories for analysis: (1) those who worked in the mercury recycling operation (Group A, n = 8), (2) those who worked at the facility but not in the yard where the recycling was done (Group B, n = 14), and (3) those who did not work at the facility (Group C, n = 7). Urine, blood, hair, and nail samples were collected from the participants, and a questionnaire was administered to obtain data on age, gender, occupational history, smoking, alcohol consumption, fish consumption, tattoos, dental amalgams, home heating system, education, source of drinking water, and family employment in the former mercury mine/smelter located on the site of the recycling facility. Each factor was tested in a univariate regression with total mercury in urine, blood, hair, and nails. Median biomarker concentrations were 4.04 ??g/g-Cr (urine), 2.58 ??g/L (blood), 3.95 ??g/g (hair), and 1.16 ??g/g (nails). Occupational category was significantly correlated (p < 0.001) with both blood and urinary mercury concentrations but not with hair or nail mercury. Four individuals had urinary mercury concentrations in a range previously found to be associated with subtle neurological and subjective symptoms (e.g., fatigue, loss of appetite, irritability), and one worker had a urinary mercury concentration in a range associated with a high probability of neurological effects and proteinuria. Comparison of results by occupational category found that workers directly involved with the recycling operation had the highest blood and urinary mercury levels. Those who worked at the facility but were not directly involved with the recycling operation had higher levels than those who did not work at the facility. Copyright ?? 2008 JOEH, LLC.

  14. Co-exposure to radiation and methyl mercury during a critical phase of neonatal brain development in mice enhances developmental neuro-behavioral effects

    International Nuclear Information System (INIS)

    Sundell-Bergman, Synnoeve; Eriksson, Per; Fredriksson, Anders; Fischer, Celia; Stenerloew, Bo

    2008-01-01

    Full text: Organisms, including man, are continuously exposed to low doses of ionizing radiation as well as persistent and non persistent chemicals in the environment. Hence, in the process of developing numerical limits for environmental protection, there is a strong need to consider interactive effects between radiation and other environmental stressors. It is known that ionizing radiation, as well as methyl mercury, can give rise to neuro-toxicological and neuro behavioural effects in mammals and that developmental neurotoxic effects can be seen after exposure during gestation. However, there is a lack of knowledge concerning effects and consequences from low-dose exposure during critical phases of perinatal and/or neonatal brain development and the combination of ionizing radiation and environmental chemicals. Epidemiological studies of patients with haemangioma have indicated that radiation exposures to the brain during infancy might deteriorate cognitive ability in adulthood. Ten-day old neonatal NMRI male mice were exposed to a single oral dose of MeHg (0.40 or 4.0 mg/kg bw). Four hours after the MeHg exposure the mice were irradiated with 60 Co gamma radiation at doses of 0,2 and 0,5 Gy. The animals were subjected to a spontaneous behaviour test at the ages of 2- and 4-months, and the water maze test at the age of 5 months. Neither the single dose of MeHg (0.4 mg/kg bw) nor the radiation dose of 0.2 Gy affected the spontaneous behavior, but the co-exposure to radiation and MeHg caused developmental neurotoxic effects. These effects were manifested as disrupted spontaneous behavior, lack of habituation, and impaired learning and memory functions. Studies are continuing to verify the effects ant to elucidate possible underlying mechanisms. (author)

  15. Total mercury and methyl-mercury contents and accumulation in polar microbial mats.

    Science.gov (United States)

    Camacho, Antonio; Rochera, Carlos; Hennebelle, Raphaëlle; Ferrari, Christophe; Quesada, Antonio

    2015-03-15

    Although polar regions are considered isolated and pristine areas, the organisms that inhabit these zones are exposed to global pollution. Heavy metals, such as mercury, are global pollutants and can reach almost any location on Earth. Mercury may come from natural, volcanic or geological sources, or result from anthropogenic sources, in particular industrial or mining activities. In this study, we have investigated one of the most prominent biological non-marine communities in both polar regions, microbial mats, in terms of their Hg and methyl-mercury (MeHg) concentrations and accumulation capacities. The main hypotheses posed argued on the importance of different factors, and to test them, we have measured Hg concentrations in microbial mats that were collected from 6 locations in different ecological situations. For this purpose, the direct anthropogenic impacts, volcanic influences, proximity to the seashore, latitudinal gradients and C contents were investigated. Our results show that, other than the direct anthropogenic influence, none of the other hypotheses alone satisfactorily explains the Hg content in microbial mats. In contrast, the MeHg contents were noticeably different between the investigated locations, with a higher proportion of MeHg on the McMurdo Ice Shelf (Antarctica) and a lower proportion on Ward Hunt Island (High Arctic). Furthermore, our results from in situ experiments indicated that the microbial mats from South Shetland Islands could quickly accumulate (48 h) Hg when Hg dissolved salts were supplied. Over short-term periods, these mats do not transform Hg into MeHg under field conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Mercury exposure may suppress baseline corticosterone levels in juvenile birds.

    Science.gov (United States)

    Herring, Garth; Ackerman, Joshua T; Herzog, Mark P

    2012-06-05

    Mercury exposure has been associated with a wide variety of negative reproductive responses in birds, however few studies have examined the potential for chick impairment via the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates corticosterone levels during periods of stress. We examined the relationship between baseline fecal corticosterone metabolite concentrations and mercury concentrations in down feathers of recently hatched (feathers (decreasing by 45% across the range of observed mercury concentrations) while accounting for stronger positive correlations between corticosterone concentrations and colony nest abundance and date. These results indicate that chronic mercury exposure may suppress baseline corticosterone concentrations in tern chicks and suggests that a juvenile bird's ability to respond to stress may be reduced via the downregulation of the HPA axis.

  17. Total- and methyl-mercury concentrations and methylation rates across the freshwater to hypersaline continuum of the Great Salt Lake, Utah, USA

    Science.gov (United States)

    Johnson, William P.; Swanson, Neil; Black, Brooks; Rudd, Abigail; Carling, Gregory; Fernandez, Diego P.; Luft, John; Van Leeuwen, Jim; Marvin-DiPasquale, Mark C.

    2015-01-01

    We examined mercury (Hg) speciation in water and sediment of the Great Salt Lake and surrounding wetlands, a locale spanning fresh to hypersaline and oxic to anoxic conditions, in order to test the hypothesis that spatial and temporal variations in Hg concentration and methylation rates correspond to observed spatial and temporal trends in Hg burdens previously reported in biota. Water column, sediment, and pore water concentrations of methylmercury (MeHg) and total mercury (THg), as well as related aquatic chemical parameters were examined. Inorganic Hg(II)-methylation rates were determined in selected water column and sediment subsamples spiked with inorganic divalent mercury (204Hg(II)). Net production of Me204Hg was expressed as apparent first-order rate constants for methylation (kmeth), which were also expanded to MeHg production potential (MPP) rates via combination with tin reducible ‘reactive’ Hg(II) (Hg(II)R) as a proxy for bioavailable Hg(II). Notable findings include: 1) elevated Hg concentrations previously reported in birds and brine flies were spatially proximal to the measured highest MeHg concentrations, the latter occurring in the anoxic deep brine layer (DBL) of the Great Salt Lake; 2) timing of reduced Hg(II)-methylation rates in the DBL (according to both kmeth and MPP) coincides with reduced Hg burdens among aquatic invertebrates (brine shrimp and brine flies) that act as potential vectors of Hg propagation to the terrestrial ecosystem; 3) values ofkmeth were found to fall within the range reported by other studies; and 4) MPP rates were on the lower end of the range reported in methodologically comparable studies, suggesting the possibility that elevated MeHg in the anoxic deep brine layer results from its accumulation and persistence in this quasi-isolated environment, due to the absence of light (restricting abiotic photo demethylation) and/or minimal microbiological demethylation.

  18. Novel methodology for the study of mercury methylation and reduction in sediments and water using {sup 197}Hg radiotracer

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro Guevara, Sergio; Perez Catan, Soledad [Centro Atomico Bariloche, Laboratorio de Analisis por Activacion Neutronica, Bariloche (Argentina); Zizek, Suzana; Repinc, Urska; Jacimovic, Radojko; Horvat, Milena [Jozef Stefan Institute, Department of Environmental Sciences, Ljubljana (Slovenia)

    2007-03-15

    Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H{sub 2}SO{sub 4} or HCl were evaluated in freshwater sediments using {sup 197}Hg radiotracer. Values obtained for the {sup 197}Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of {sup 197}Hg{sup 2+} into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg{sup 2+} contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg{sup 2+} contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H{sub 2}SO{sub 4} method is recommended, since it is free from these interferences. {sup 197}Hg radiotracer (T{sub 1/2} = 2.673 d) has a production rate that is about 50 times higher than that of {sup 203}Hg (T{sub 1/2} = 46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to {sup 203}Hg when it is used it in short-term experiments and produced by the irradiation of {sup 196}Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the {sup 196}Hg isotope is increased, the specific activity of the {sup 197}Hg tracer can be significantly improved. In

  19. Mercury exposure in children: a review

    International Nuclear Information System (INIS)

    Counter, S. Allen; Buchanan, Leo H.

    2004-01-01

    Exposure to toxic mercury (Hg) is a growing health hazard throughout the world today. Recent studies show that mercury exposure may occur in the environment, and increasingly in occupational and domestic settings. Children are particularly vulnerable to Hg intoxication, which may lead to impairment of the developing central nervous system, as well as pulmonary and nephrotic damage. Several sources of toxic Hg exposure in children have been reported in biomedical literature: (1) methylmercury, the most widespread source of Hg exposure, is most commonly the result of consumption of contaminated foods, primarily fish; (2) ethylmercury, which has been the subject of recent scientific inquiry in relation to the controversial pediatric vaccine preservative thimerosal; (3) elemental Hg vapor exposure through accidents and occupational and ritualistic practices; (4) inorganic Hg through the use of topical Hg-based skin creams and in infant teething powders; (5) metallic Hg in dental amalgams, which release Hg vapors, and Hg 2+ in tissues. This review examines recent epidemiological studies of methylmercury exposure in children. Reports of elemental Hg vapor exposure in children through accidents and occupational practices, and the more recent observations of the increasing use of elemental Hg for magico-religious purposes in urban communities are also discussed. Studies of inorganic Hg exposure from the widespread use of topical beauty creams and teething powders, and fetal/neonatal Hg exposure from maternal dental amalgam fillings are reviewed. Considerable attention was given in this review to pediatric methylmercury exposure and neurodevelopment because it is the most thoroughly investigated Hg species. Each source of Hg exposure is reviewed in relation to specific pediatric health effects, particularly subtle neurodevelopmental disorders

  20. Biomarkers of mercury exposure at a mercury recycling facility in Ukraine.

    Science.gov (United States)

    Gibb, Herman Jones; Kozlov, Kostj; Buckley, Jessie Poulin; Centeno, Jose; Jurgenson, Vera; Kolker, Allan; Conko, Kathryn; Landa, Edward; Panov, Boris; Panov, Yuri; Xu, Hanna

    2008-08-01

    This study evaluates biomarkers of occupational mercury exposure among workers at a mercury recycling operation in Gorlovka, Ukraine. The 29 study participants were divided into three occupational categories for analysis: (1) those who worked in the mercury recycling operation (Group A, n = 8), (2) those who worked at the facility but not in the yard where the recycling was done (Group B, n = 14), and (3) those who did not work at the facility (Group C, n = 7). Urine, blood, hair, and nail samples were collected from the participants, and a questionnaire was administered to obtain data on age, gender, occupational history, smoking, alcohol consumption, fish consumption, tattoos, dental amalgams, home heating system, education, source of drinking water, and family employment in the former mercury mine/smelter located on the site of the recycling facility. Each factor was tested in a univariate regression with total mercury in urine, blood, hair, and nails. Median biomarker concentrations were 4.04 microg/g-Cr (urine), 2.58 microg/L (blood), 3.95 microg/g (hair), and 1.16 microg/g (nails). Occupational category was significantly correlated (p recycling operation had the highest blood and urinary mercury levels. Those who worked at the facility but were not directly involved with the recycling operation had higher levels than those who did not work at the facility.

  1. Influence of the Sostanj coal-fired thermal power plant on mercury and methyl mercury concentrations in Lake Velenje, Slovenia

    Energy Technology Data Exchange (ETDEWEB)

    Kotnik, J.; Horvat, M.; Mandic, V.; Logar, M. [Department of Environmental Sciences, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)

    2000-10-02

    Lake Velenje is located in one of the most polluted regions in Slovenia, the Salek Valley. The major source of pollution in the valley is the coal-fired thermal power plant in Sostanj (STPP, capacity 775 MW). It has five separate units. All units have electrostatic precipitators for fly ash removal. Unit 4 also has installed a wet flue gas desulfurisation system (FGD system). Total mercury (THg) concentrations were measured in lignite, slag and ash samples from the STPP. In flue gas, different mercury species (THg, MeHg, Hg{sup 2+}, Hg{sup 0}) were determined separately for unit 4 and unit 5 which use different flue gas cleaning technology. Mercury and methyl mercury (MeHg) concentrations were also measured in lake water at different depths, in inflow water, outflow water, rain, snow and lake sediments in order to establish the influence of the power plant on the lake. Most mercury emitted from the power plant is in the elemental form. The ratio between oxidised and elemental Hg depends on the flue gas cleaning technology. Mass balance calculations have been performed for the STPP. The results show that the major sources of mercury in Lake Velenje are wet deposition and lake inflows. Total and MeHg concentrations in the water column are very low and can be compared to other non-contaminated freshwater lakes in the world.

  2. Influence of the Sostanj coal-fired thermal power plant on mercury and methyl mercury concentrations in Lake Velenje, Slovenia

    Science.gov (United States)

    Kotnik; Horvat; Mandic; Logar

    2000-10-02

    Lake Velenje is located in one of the most polluted regions in Slovenia, the Salek Valley. The major source of pollution in the valley is the coal-fired thermal power plant in Sostanj (STPP, capacity 775 MW). It has five separate units. All units have electrostatic precipitators for fly ash removal. Unit 4 also has installed a wet flue gas desulfurisation system (FGD system). Total mercury (THg) concentrations were measured in lignite, slag and ash samples from the STPP. In flue gas, different mercury species (THg, MeHg, Hg2+, Hg0) were determined separately for unit 4 and unit 5 which use different flue gas cleaning technology. Mercury and methyl mercury (MeHg) concentrations were also measured in lake water at different depths, in inflow water, outflow water, rain, snow and lake sediments in order to establish the influence of the power plant on the lake. Most mercury emitted from the power plant is in the elemental form. The ratio between oxidised and elemental Hg depends on the flue gas cleaning technology. Mass balance calculations have been performed for the STPP. The results show that the major sources of mercury in Lake Velenje are wet deposition and lake inflows. Total and MeHg concentrations in the water column are very low and can be compared to other non-contaminated freshwater lakes in the world.

  3. Total and methyl mercury concentrations and fluxes from small boreal forest catchments in Finland

    International Nuclear Information System (INIS)

    Porvari, Petri; Verta, Matti

    2003-01-01

    Peatlands have higher methyl mercury output than uplands. - Total mercury (TotHg) and methyl mercury (MeHg) concentrations were studied in runoff from eight small (0.02-1.3 km 2 ) boreal forest catchments (mineral soil and peatland) during 1990-1995. Runoff waters were extremely humic (TOC 7-70 mg l -1 ). TotHg concentrations varied between 0.84 and 24 ng l -1 and MeHg between 0.03 and 3.8 ng l -1 . TotHg fluxes from catchments ranged from 0.92 to 1.8 g km -2 a -1 , and MeHg fluxes from 0.03 to 0.33 g km -2 a -1 . TotHg concentrations and output fluxes measured in runoff water from small forest catchments in Finland were comparable with those measured in other boreal regions. By contrast, MeHg concentrations were generally higher. Estimates for MeHg output fluxes in this study were comparable at sites with forests and wetlands in Sweden and North America, but clearly higher than those measured at upland or agricultural sites in other studies. Peatland catchments released more MeHg than pure mineral soil or mineral soil catchments with minor area of peatland

  4. Chronic inorganic mercury exposure induces sex-specific changes in central TNFα expression: Importance in autism?

    OpenAIRE

    Curtis, J. Thomas; Chen, Yue; Buck, Daniel J.; Davis, Randall L.

    2011-01-01

    Mercury is neurotoxic and increasing evidence suggests that environmental exposure to mercury may contribute to neuropathologies including Alzheimer's disease and autism spectrum disorders. Mercury is known to disrupt immunocompetence in the periphery, however, little is known about the effects of mercury on neuroimmune signaling. Mercury-induced effects on central immune function are potentially very important given that mercury exposure and neuroinflammation both are implicated in certain n...

  5. Exposure to mercury and silver during removal of amalgam restorations

    International Nuclear Information System (INIS)

    Brune, D.; Hensten-Pettersen, A.; Beltesbrekke, H.

    1980-01-01

    The content of particulate matter and mercury vapor in dentist breathing air during removal of amalgam restorations was assessed. Mercury and silver were quantitatively assayed by nuclerar chemical analysis, and the mercury vapor concentration was measured with a sniffer. When the water spray was not used, the short time threshold limit values for exposure to mercury and silver were exceeded about 10 times. With water spray the mercury content was reduced to a level considerably lower that the threshold limit value, whereas the silver concentration slightly exceeded the corresponding limit. (author)

  6. Exposure to mercury and silver during removal of amalgam restorations

    International Nuclear Information System (INIS)

    Brune, D.; Hensten-Pettersen, A.; Beltesbrekke, H.

    1980-01-01

    The content of particulate matter and mercury vapor in dentist breathing air during removal of amalgam restorations was assessed. Mercury and silver were quantitatively assayed by nuclear chemical analysis, and the mercury vapor concentration was measured with a sniffer. When the water spray was not used, the short time threshold limit values for exposure to mercury and silver were exceeded about 10 times. With water spray the mercury content was reduced to a level considerably lower than the threshold limit value, whereas the silver concentration slightly exceeded the corresponding limit. (author)

  7. Mercury exposure may influence fluctuating asymmetry in waterbirds

    Science.gov (United States)

    Herring, Garth; Eagles-Smith, Collin A.; Ackerman, Joshua T.

    2017-01-01

    Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds.

  8. Mercury Exposure in Young Adulthood and Incidence of Diabetes Later in Life

    Science.gov (United States)

    He, Ka; Xun, Pengcheng; Liu, Kiang; Morris, Steve; Reis, Jared; Guallar, Eliseo

    2013-01-01

    OBJECTIVE Laboratory studies suggest that exposure to methylmercury at a level similar to those found in fish may induce pancreatic islet β-cell dysfunction. Few, if any, human studies have examined the association between mercury exposure and diabetes incidence. We examined whether toenail mercury levels are associated with incidence of diabetes in a large prospective cohort. RESEACH DESIGN AND METHODS A prospective cohort of 3,875 American young adults, aged 20–32 years, free of diabetes in 1987 (baseline), were enrolled and followed six times until 2005. Baseline toenail mercury levels were measured with instrumental neutron-activation analysis. Incident diabetes was identified by plasma glucose levels, oral glucose tolerance tests, hemoglobin A1C levels, and/or antidiabetes medications. RESULTS A total of 288 incident cases of diabetes occurred over 18 years of follow-up. In multivariate analyses adjusted for age, sex, ethnicity, study center, education, smoking status, alcohol consumption, physical activity, family history of diabetes, intakes of long-chain n-3 fatty acids and magnesium, and toenail selenium, toenail mercury levels were positively associated with the incidence of diabetes. The hazard ratio (95% CI) of incident diabetes compared the highest to the lowest quintiles of mercury exposure was 1.65 (1.07–2.56; P for trend = 0.02). Higher mercury exposure at baseline was also significantly associated with decreased homeostasis model assessment of β-cell function index (P for trend mercury exposure in young adulthood may have elevated risk of diabetes later in life. PMID:23423697

  9. Transcriptomics analysis of interactive effects of benzene, trichloroethylene and methyl mercury within binary and ternary mixtures on the liver and kidney following subchronic exposure in the rat

    NARCIS (Netherlands)

    Hendriksen, P.J.M.; Freidig, A.P.; Jonker, D.; Thissen, U.; Bogaards, J.J.P.; Mumtaz, M.M.; Groten, J.P.; Stierum, R.H.

    2007-01-01

    The present research aimed to study the interaction of three chemicals, methyl mercury, benzene and trichloroethylene, on mRNA expression alterations in rat liver and kidney measured by microarray analysis. These compounds were selected based on presumed different modes of action. The chemicals were

  10. Prenatal methyl mercury exposure in relation to neurodevelopment and behavior at 19 years of age in the Seychelles Child Development Study.

    Science.gov (United States)

    van Wijngaarden, E; Thurston, S W; Myers, G J; Strain, J J; Weiss, B; Zarcone, T; Watson, G E; Zareba, G; McSorley, E M; Mulhern, M S; Yeates, A J; Henderson, J; Gedeon, J; Shamlaye, C F; Davidson, P W

    2013-01-01

    Fish are important sources of protein and contain a variety of nutrients, such as n-3 long-chain polyunsaturated fatty acids (PUFA), essential for normal brain development. Nevertheless, all fish also contain methyl mercury (MeHg), a known neurotoxicant in adequate dosage. Our studies of the Seychelles Child Development Study (SCDS) Main Cohort enrolled in 1989-1990 (n=779) have found no consistent pattern of adverse MeHg effects at exposures achieved by daily fish consumption. Rather, we have observed evidence of improved performance on some cognitive endpoints as prenatal MeHg exposure increases in the range studied. These observations cannot be related to MeHg and may reflect the role of unmeasured covariates such as essential nutrients present in fish. To determine if these associations persist into young adulthood, we examined the relationship between prenatal MeHg exposure, recent PUFA exposure and subjects' neurodevelopment and behavior at 19 years of age. We examined 533 participants using the following test battery: the Profile of Mood States-Bipolar (POMS-Bi); Finger Tapping; Kaufman Brief Intelligence Test (K-BIT); measures of Fine Motor Control and Complex Perceptual Motor Control; and Visual Spatial Contrast Sensitivity. We collected the following covariates: maternal IQ, family life course stressors, socioeconomic status, and subjects' recent postnatal MeHg, sex, and computer use. Primary analyses (based on N=392-475) examined covariate-adjusted associations in multiple linear regression models with prenatal MeHg as the primary exposure measure. Secondary analyses additionally adjusted for total n-6 and fish-related n-3 PUFA measured in the subjects' serum at the 19-year examination. Study participants had a mean prenatal MeHg exposure of 6.9 ppm, and a mean recent postnatal exposure of 10.3 ppm. There were no adverse associations between prenatal MeHg and any of the measured endpoints. For recent postnatal MeHg exposure, however, adverse associations

  11. Glutathione level after long-term occupational elemental mercury exposure

    International Nuclear Information System (INIS)

    Kobal, Alfred Bogomir; Prezelj, Marija; Horvat, Milena; Krsnik, Mladen; Gibicar, Darija; Osredkar, Josko

    2008-01-01

    Many in vitro and in vivo studies have elucidated the interaction of inorganic mercury (Hg) and glutathione. However, human studies are limited. In this study, we investigated the potential effects of remote long-term intermittent occupational elemental Hg vapour (Hg o ) exposure on erythrocyte glutathione levels and some antioxidative enzyme activities in ex-mercury miners in the period after exposure. The study included 49 ex-mercury miners divided into subgroups of 28 still active, Hg o -not-exposed miners and 21 elderly retired miners, and 41 controls, age-matched to the miners subgroup. The control workers were taken from 'mercury-free works'. Reduced glutathione (GSH) and oxidized disulphide glutathione (GSSG) concentrations in haemolysed erythrocytes were determined by capillary electrophoresis, while total glutathione (total GSH) and the GSH/GSSG ratio were calculated from the determined values. Catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in erythrocytes were measured using commercially available reagent kits, while urine Hg (U-Hg) concentrations were determined by cold vapour atomic absorption (CVAAS). No correlation of present U-Hg levels, GSH, GSSG, and antioxidative enzymes with remote occupational biological exposure indices were found. The mean CAT activity in miners and retired miners was significantly higher (p o could be an inductive and additive response to maintain the balance between GSH and antioxidative enzymes in interaction with the Hg body burden accumulated during remote occupational exposure, which does not represent a severely increased oxidative stress

  12. Neuropsychological alterations in mercury intoxication persist several years after exposure.

    Science.gov (United States)

    Zachi, Elaine Cristina; Taub, Anita; Faria, Marcília de Araújo Medrado; Ventura, Dora Fix

    2008-01-01

    Elemental mercury is a liquid toxic metal widely used in industry. Occupational exposure occurs mainly via inhalation. Previously, neuropsychological assessment detected deficits in former workers of a fluorescent lamp plant who had been exposed to elemental mercury vapor and were away from exposure for several years at the time of examination. The purpose of this work was to reexamine these functions after 18 months in order to evaluate their progression. Thirteen participants completed tests of attention, inhibitory control, verbal/visual memory, psychomotor speed, verbal fluency, visuomotor ability, executive function, semantic knowledge, and depression and anxiety inventories on 2 separate occasions. At baseline, the former workers indicated slower psychomotor and information processing speed, verbal spontaneous recall memory impairment, and increased depression and anxiety symptoms compared to controls (Precovery of functions, the neuropsychological effects related to mercury exposure are found to persist for many years.

  13. Human Mercury Exposure in Yanomami Indigenous Villages from the Brazilian Amazon.

    Science.gov (United States)

    Vega, Claudia M; Orellana, Jesem D Y; Oliveira, Marcos W; Hacon, Sandra S; Basta, Paulo C

    2018-05-23

    In the Brazilian Amazon, where the majority of Yanomami villages are settled, mercury (Hg) exposure due to artisanal small-scale gold mining (ASGM) has been reported since the 1980s. This study assessed mercury exposure in the Yanomami reserve and whether the level of contamination was related to the ASGM geographical location. It was conducted using a cross-sectional study of 19 villages. Direct interviews were performed and hair samples were used as a bioindicator of Hg exposure. The Prevalence-Ratio (PR) was estimated as an indicator of association between ASGM geographical locations and human exposure to mercury. Mercury levels (239 hair samples) ranged between 0.4 and 22.1 μg·g -1 and presented substantial differences amongst the villages. In the Waikas-Aracaça region, where current ASGM was reported, we observed the highest Hg concentrations (median = 15.5 μg·g -1 ). Almost all participants presented with hair-Hg levels >6 μg·g -1 (prevalence = 92.3%). In the Paapiu region, we observed the lowest concentrations (median = 3.2 μg·g -1 ; prevalence = 6.7%). Our findings showed that the Waikas Ye'kuana and Waikas Aracaca villages presented with 4.4 (PR = 4.4; Confidence Interval (CI) 95% = 2.2⁻9.0) and 14.0 (PR = 14.0; CI 95% = 7.9⁻24.9) times higher prevalence of hair-Hg concentration, respectively, compared with Paapiu. Considering seasonal variation of Hg-exposure, the lowest concentrations were observed during the wet season (June⁻September) and the highest in the dry season (December⁻April). Our study suggests that there is an association between mercury exposure and ASGM geographical locations.

  14. Distribution of mercury in guinea pig offspring after in utero exposure to mercury vapor during late gestation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Minoru; Yamamura, Yukio; Sataoh, Hiroshi

    1986-04-01

    Organ distribution of mercury after in utero mercury vapor exposure was investigated in neonatal guinea pigs. Mother guinea pigs in late gestation were exposed to 0.2-0.3 mg/m/sup 3/ mercury vapor 2 h per day until giving birth. Mercury concentrations in neonatal brain, lungs, heart, kidneys, plasma and erythrocytes were much lower than those of maternal organs and tissues. Neonatal liver, however, showed a mercury concentration twice as high as maternal liver. Mercury concentration ratios of erythrocytes to plasma in offspring were quite different from those of mothers, being 0.2-0.4 for offspring, and 1.3-3.0 for mothers. These results suggested that mercury vapor metabolism in fetuses was quite different from that in their mothers. This may be due to the different blood circulation, as mercury vapor transferred through the placental barrier would be rapidly oxidized into ionic mercury in fetal liver and accumulated in the organ. The different mercury vapor metabolism may prevent fetal brain, which is rapidly developing, and thus vulnerable, from being exposed to excessive mercury vapor.

  15. Age standardized cancer mortality ratios in areas heavily exposed to methyl mercury.

    Science.gov (United States)

    Yorifuji, Takashi; Tsuda, Toshihide; Kawakami, Norito

    2007-08-01

    Methyl-mercury (MeHg) was discharged from a chemical factory in Minamata, and consequently spread throughout the Shiranui Sea in Kumamoto, Japan. Although many studies have focused on MeHg-induced neurological disorders, the association between MeHg and malignant neoplasms has not been adequately investigated. Therefore, we explored this association using the age standardized mortality ratio (ASMR) in an ecologic study over a wide area allowing for a long empirical induction period. The subjects were residents in areas around the Shiranui Sea. We divided these areas into exposure groups 1 (Minamata and Ashikita regions) and 2 (Amakusa region). Exposure group 1 was contaminated from the late 1930s, and exposure group 2 was contaminated from the late 1950s. In addition, exposure group 1 was contaminated more heavily than exposure group 2. There were 92,525 and 152,541 residents in each group in 1960, respectively. We analyzed the cancer ASMR in both exposure groups using data from two reference populations (Japan and Kumamoto prefecture) from 1961 to 1997. There were 94,301,494 and 1,856,192 people in each reference group in 1960, respectively. We abstracted population and mortality data from the censuses and the vital statistics of the prefecture and Japan. An increased leukemia ASMR and a decreased gastric cancer ASMR were observed in both exposure groups, while other ASMRs were around unity and less precise. Furthermore, the leukemia ASMRs were elevated differently between the two exposure groups: the leukemia ASMR was already elevated early in the study period in exposure group 1 and increased gradually in exposure group 2. While the negative association between MeHg and gastric cancer might be explained by salt intake, the positive association between MeHg and leukemia could not be explained by potential confounders. Despite some limitations mainly due to its ecologic design, this study indicates the necessity of an individual-level study evaluating the

  16. Stimulation of erythrocyte phosphatidylserine exposure by mercury ions

    International Nuclear Information System (INIS)

    Eisele, Kerstin; Lang, Philipp A.; Kempe, Daniela S.; Klarl, Barbara A.; Niemoeller, Olivier; Wieder, Thomas; Huber, Stephan M.; Duranton, Christophe; Lang, Florian

    2006-01-01

    The sequelae of mercury intoxication include induction of apoptosis. In nucleated cells, Hg 2+ -induced apoptosis involves mitochondrial damage. The present study has been performed to elucidate effects of Hg 2+ in erythrocytes which lack mitochondria but are able to undergo apoptosis-like alterations of the cell membrane. Previous studies have documented that activation of a Ca 2+ -sensitive erythrocyte scramblase leads to exposure of phosphatidylserine at the erythrocyte surface, a typical feature of apoptotic cells. The erythrocyte scramblase is activated by osmotic shock, oxidative stress and/or energy depletion which increase cytosolic Ca 2+ activity and/or activate a sphingomyelinase leading to formation of ceramide. Ceramide sensitizes the scramblase to Ca 2+ . The present experiments explored the effect of Hg 2+ ions on erythrocytes. Phosphatidylserine exposure after mercury treatment was estimated from annexin binding as determined in FACS analysis. Exposure to Hg 2+ (1 μM) indeed significantly increased annexin binding from 2.3 ± 0.5% (control condition) to 23 ± 6% (n = 6). This effect was paralleled by activation of a clotrimazole-sensitive K + -selective conductance as measured by patch-clamp recordings and by transient cell shrinkage. Further experiments revealed also an increase of ceramide formation by ∼66% (n = 7) after challenge with mercury (1 μM). In conclusion, mercury ions activate a clotrimazole-sensitive K + -selective conductance leading to transient cell shrinkage. Moreover, Hg 2+ increases ceramide formation. The observed mechanisms could similarly participate in the triggering of apoptosis in nucleated cells by Hg 2+

  17. Atlantic Bottlenose Dolphins (Tursiops truncatus as A Sentinel for Exposure to Mercury in Humans: Closing the Loop

    Directory of Open Access Journals (Sweden)

    John S. Reif

    2015-11-01

    Full Text Available Mercury (Hg is a ubiquitous global contaminant with important public health implications. Mercury is released from a variety of anthropogenic, industrial processes, enters the earth's atmosphere and is re-deposited onto the earth’s surface in rainfall. Much of this Hg enters the oceans which cover the majority of the earth’s surface. In the marine environment, inorganic Hg is converted to the most toxic form of the element, methylmercury, and biomagnified through the trophic levels of the food web. The bottlenose dolphin (Tursiops truncatus is the apex predator in many estuarine and coastal ecosystems. Due to their long life span and trophic position, bottlenose dolphins bioaccumulate high concentrations of contaminants including Hg, thus making them an important sentinel species for ecosystem and public health. Bottlenose dolphins in Florida bioaccumulate high concentrations of Hg in their blood, skin and internal organs. The concentrations of Hg in blood and skin of bottlenose dolphins of the Indian River Lagoon, FL (IRL are among the highest reported world-wide. In previous studies, we demonstrated associations between concentrations of total Hg in the blood and skin of IRL dolphins and markers of endocrine, renal, hepatic, hematologic and immune system dysfunction. The predominant manifestation of exposure to mercury in humans is neurotoxicity. During the 1950s and 1960s, residents of Minamata bay, Japan were exposed to high concentrations of methyl mercury as the result of ingestion of fish and shellfish that had become contaminated in this infamous environmental disaster. Affected adults had severe motor and sensory abnormalities often leading to death. Methyl mercury crosses the placenta during pregnancy. Children exposed in utero were born with multiple congenital anomalies and also suffered from neurologic disorders. Significantly, local cats that consumed Hg contaminated fish developed severe signs of neurotoxicity which led to

  18. Factors Affecting Elevated Arsenic and Methyl Mercury Concentrations in Small Shield Lakes Surrounding Gold Mines near the Yellowknife, NT, (Canada Region.

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    Adam James Houben

    Full Text Available Gold mines in the Yellowknife, NT, region--in particular, the Giant Mine--operated from 1949-99, releasing 237,000 tonnes of waste arsenic trioxide (As2O3 dust, among other compounds, from gold ore extraction and roasting processes. For the first time, we show the geospatial distribution of roaster-derived emissions of several chemical species beyond the mine property on otherwise undisturbed taiga shield lakes within a 25 km radius of the mine, 11 years after its closing. Additionally, we demonstrate that underlying bedrock is not a significant source for the elevated concentrations in overlying surface waters. Aquatic arsenic (As concentrations are well above guidelines for drinking water (10 μg/L and protection for aquatic life (5 μg/L, ranging up to 136 μg/L in lakes within 4 km from the mine, to 2.0 μg/L in lakes 24 km away. High conversion ratios of methyl mercury were shown in lakes near the roaster stack as well, with MeHg concentrations reaching 44% of total mercury. The risk of elevated exposures by these metals is significant, as many lakes used for recreation and fishing near the City of Yellowknife are within this radius of elevated As and methyl Hg concentrations.

  19. Assessment of mercury exposure among small-scale gold miners using mercury stable isotopes

    International Nuclear Information System (INIS)

    Sherman, Laura S.; Blum, Joel D.; Basu, Niladri; Rajaee, Mozhgon; Evers, David C.; Buck, David G.; Petrlik, Jindrich; DiGangi, Joseph

    2015-01-01

    Total mercury (Hg) concentrations in hair and urine are often used as biomarkers of exposure to fish-derived methylmercury (MeHg) and gaseous elemental Hg, respectively. We used Hg stable isotopes to assess the validity of these biomarkers among small-scale gold mining populations in Ghana and Indonesia. Urine from Ghanaian miners displayed similar Δ 199 Hg values to Hg derived from ore deposits (mean urine Δ 199 Hg=0.01‰, n=6). This suggests that urine total Hg concentrations accurately reflect exposure to inorganic Hg among this population. Hair samples from Ghanaian miners displayed low positive Δ 199 Hg values (0.23–0.55‰, n=6) and low percentages of total Hg as MeHg (7.6–29%, n=7). These data suggest that the majority of the Hg in these miners' hair samples is exogenously adsorbed inorganic Hg and not fish-derived MeHg. Hair samples from Indonesian gold miners who eat fish daily displayed a wider range of positive Δ 199 Hg values (0.21–1.32‰, n=5) and percentages of total Hg as MeHg (32–72%, n=4). This suggests that total Hg in the hair samples from Indonesian gold miners is likely a mixture of ingested fish MeHg and exogenously adsorbed inorganic Hg. Based on data from both populations, we suggest that total Hg concentrations in hair samples from small-scale gold miners likely overestimate exposure to MeHg from fish consumption. - Highlights: • Mercury isotopes were measured in hair and urine from small-scale gold miners. • Mercury isotopes indicate that Hg in urine comes from mining activity. • Mercury isotopes suggest Hg in hair is a mixture of fish MeHg and inorganic Hg. • A large percentage of Hg in miner’s hair is released during amalgam burning and adsorbed

  20. Novel methodology for the study of mercury methylation and reduction in sediments and water using 197Hg radiotracer.

    Science.gov (United States)

    Ribeiro Guevara, Sergio; Zizek, Suzana; Repinc, Urska; Pérez Catán, Soledad; Jaćimović, Radojko; Horvat, Milena

    2007-03-01

    Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H2SO4 or HCl were evaluated in freshwater sediments using 197Hg radiotracer. Values obtained for the 197Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of 197Hg2+ into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg2+ contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg2+ contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H2SO4 method is recommended, since it is free from these interferences. 197Hg radiotracer (T1/2=2.673 d) has a production rate that is about 50 times higher than that of 203Hg (T1/2=46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to 203Hg when it is used it in short-term experiments and produced by the irradiation of 196Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the 196Hg isotope is increased, the specific activity of the 197Hg tracer can be significantly improved. In the present work, 197Hg tracer was produced from mercury 51.58% enriched in the 196Hg isotope, and a 340-fold

  1. Climate Change Impacts on Environmental and Human Exposure to Mercury in the Arctic

    Science.gov (United States)

    Sundseth, Kyrre; Pacyna, Jozef M.; Banel, Anna; Pacyna, Elisabeth G.; Rautio, Arja

    2015-01-01

    This paper reviews information from the literature and the EU ArcRisk project to assess whether climate change results in an increase or decrease in exposure to mercury (Hg) in the Arctic, and if this in turn will impact the risks related to its harmful effects. It presents the state-of-the art of knowledge on atmospheric mercury emissions from anthropogenic sources worldwide, the long-range transport to the Arctic, and it discusses the likely environmental fate and exposure effects on population groups in the Arctic under climate change conditions. The paper also includes information about the likely synergy effects (co-benefits) current and new climate change polices and mitigation options might have on mercury emissions reductions in the future. The review concludes that reductions of mercury emission from anthropogenic sources worldwide would need to be introduced as soon as possible in order to assure lowering the adverse impact of climate change on human health. Scientific information currently available, however, is not in the position to clearly answer whether climate change will increase or decrease the risk of exposure to mercury in the Arctic. New research should therefore be undertaken to model the relationships between climate change and mercury exposure. PMID:25837201

  2. Climate change impacts on environmental and human exposure to mercury in the arctic.

    Science.gov (United States)

    Sundseth, Kyrre; Pacyna, Jozef M; Banel, Anna; Pacyna, Elisabeth G; Rautio, Arja

    2015-03-31

    This paper reviews information from the literature and the EU ArcRisk project to assess whether climate change results in an increase or decrease in exposure to mercury (Hg) in the Arctic, and if this in turn will impact the risks related to its harmful effects. It presents the state-of-the art of knowledge on atmospheric mercury emissions from anthropogenic sources worldwide, the long-range transport to the Arctic, and it discusses the likely environmental fate and exposure effects on population groups in the Arctic under climate change conditions. The paper also includes information about the likely synergy effects (co-benefits) current and new climate change polices and mitigation options might have on mercury emissions reductions in the future. The review concludes that reductions of mercury emission from anthropogenic sources worldwide would need to be introduced as soon as possible in order to assure lowering the adverse impact of climate change on human health. Scientific information currently available, however, is not in the position to clearly answer whether climate change will increase or decrease the risk of exposure to mercury in the Arctic. New research should therefore be undertaken to model the relationships between climate change and mercury exposure.

  3. Assessment of Dietary Mercury Intake and Blood Mercury Levels in the Korean Population: Results from the Korean National Environmental Health Survey 2012–2014

    Directory of Open Access Journals (Sweden)

    Seong-Ah Kim

    2016-09-01

    Full Text Available From a public health perspective, there is growing concern about dietary mercury intake as the most important source of mercury exposure. This study was performed to estimate dietary mercury exposure and to analyze the association between mercury intake and blood mercury levels in Koreans. The study subjects were 553 adults, comprising a 10% representative subsample of the Korean National Environmental Health Survey (KoNEHS 2012–2014, who completed a health examination, a face-to-face interview, and a three-day food record. Dietary mercury and methylmercury intakes were assessed from the three-day food record, and blood mercury concentration was measured using a mercury analyzer. The association between dietary mercury intake and blood mercury levels was analyzed by comparing the odds ratios for the blood mercury levels above the Human BioMonitoring (HBM I value (5 μg/L among the three groups with different mercury intakes. The average total mercury intake was 4.74 and 3.07 μg/day in males and females, respectively. The food group that contributed most to mercury intake was fish and shellfish, accounting for 77.8% of total intake. The geometric mean of the blood mercury concentration significantly and linearly increased with the mercury and methylmercury intakes (p < 0.001. The odds ratios for blood mercury levels above the HBM I value in the highest mercury and methyl mercury intake group were 3.27 (95% Confidence Interval (CI 1.79–5.95 and 3.20 (95% CI 1.77–5.79 times higher than that of the lowest intake group, respectively. Our results provide compelling evidence that blood mercury level has a strong positive association with dietary intake, and that fish and shellfish contribute most to the dietary mercury exposure.

  4. Assessment of Dietary Mercury Intake and Blood Mercury Levels in the Korean Population: Results from the Korean National Environmental Health Survey 2012–2014

    Science.gov (United States)

    Kim, Seong-Ah; Kwon, YoungMin; Kim, Suejin; Joung, Hyojee

    2016-01-01

    From a public health perspective, there is growing concern about dietary mercury intake as the most important source of mercury exposure. This study was performed to estimate dietary mercury exposure and to analyze the association between mercury intake and blood mercury levels in Koreans. The study subjects were 553 adults, comprising a 10% representative subsample of the Korean National Environmental Health Survey (KoNEHS) 2012–2014, who completed a health examination, a face-to-face interview, and a three-day food record. Dietary mercury and methylmercury intakes were assessed from the three-day food record, and blood mercury concentration was measured using a mercury analyzer. The association between dietary mercury intake and blood mercury levels was analyzed by comparing the odds ratios for the blood mercury levels above the Human BioMonitoring (HBM) I value (5 μg/L) among the three groups with different mercury intakes. The average total mercury intake was 4.74 and 3.07 μg/day in males and females, respectively. The food group that contributed most to mercury intake was fish and shellfish, accounting for 77.8% of total intake. The geometric mean of the blood mercury concentration significantly and linearly increased with the mercury and methylmercury intakes (p mercury levels above the HBM I value in the highest mercury and methyl mercury intake group were 3.27 (95% Confidence Interval (CI) 1.79–5.95) and 3.20 (95% CI 1.77–5.79) times higher than that of the lowest intake group, respectively. Our results provide compelling evidence that blood mercury level has a strong positive association with dietary intake, and that fish and shellfish contribute most to the dietary mercury exposure. PMID:27598185

  5. Mercury Exposure in Ireland: Results of the DEMOCOPHES Human Biomonitoring Study

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    Elizabeth Cullen

    2014-09-01

    Full Text Available Background: Monitoring of human exposure to mercury is important due to its adverse health effects. This study aimed to determine the extent of mercury exposure among mothers and their children in Ireland, and to identify factors associated with elevated levels. It formed part of the Demonstration of a study to Coordinate and Perform Human Biomonitoring on a European Scale (DEMOCOPHES pilot biomonitoring study. Methods: Hair mercury concentrations were determined from a convenience sample of 120 mother/child pairs. Mothers also completed a questionnaire. Rigorous quality assurance within DEMOCOPHES guaranteed the accuracy and international comparability of results. Results: Mercury was detected in 79.2% of the samples from mothers, and 62.5% of children’s samples. Arithmetic mean levels in mothers (0.262 µg/g hair and children (0.149 µg /g hair did not exceed the US EPA guidance value. Levels were significantly higher for those with higher education, and those who consumed more fish. Conclusions: The study demonstrates the benefit of human biomonitoring for assessing and comparing internal exposure levels, both on a population and an individual basis. It enables the potential harmful impact of mercury to be minimised in those highly exposed, and can therefore significantly contribute to population health.

  6. Human Mercury Exposure in Yanomami Indigenous Villages from the Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Claudia M. Vega

    2018-05-01

    Full Text Available In the Brazilian Amazon, where the majority of Yanomami villages are settled, mercury (Hg exposure due to artisanal small-scale gold mining (ASGM has been reported since the 1980s. This study assessed mercury exposure in the Yanomami reserve and whether the level of contamination was related to the ASGM geographical location. It was conducted using a cross-sectional study of 19 villages. Direct interviews were performed and hair samples were used as a bioindicator of Hg exposure. The Prevalence-Ratio (PR was estimated as an indicator of association between ASGM geographical locations and human exposure to mercury. Mercury levels (239 hair samples ranged between 0.4 and 22.1 μg·g−1 and presented substantial differences amongst the villages. In the Waikas-Aracaça region, where current ASGM was reported, we observed the highest Hg concentrations (median = 15.5 μg·g−1. Almost all participants presented with hair-Hg levels >6 μg·g−1 (prevalence = 92.3%. In the Paapiu region, we observed the lowest concentrations (median = 3.2 μg·g−1; prevalence = 6.7%. Our findings showed that the Waikas Ye’kuana and Waikas Aracaca villages presented with 4.4 (PR = 4.4; Confidence Interval (CI 95% = 2.2–9.0 and 14.0 (PR = 14.0; CI 95% = 7.9–24.9 times higher prevalence of hair-Hg concentration, respectively, compared with Paapiu. Considering seasonal variation of Hg-exposure, the lowest concentrations were observed during the wet season (June–September and the highest in the dry season (December–April. Our study suggests that there is an association between mercury exposure and ASGM geographical locations.

  7. Risk factors for mercury exposure of children in a rural mining town in northern Chile.

    Directory of Open Access Journals (Sweden)

    Johan Ohlander

    Full Text Available Traditional gold mining is associated with mercury exposure. Especially vulnerable to its neurotoxic effects is the developing nervous system of a child. We aimed to investigate risk factors of mercury exposure among children in a rural mining town in Chile.Using a validated questionnaire distributed to the parents of the children, a priori mercury risk factors, potential exposure pathways and demographics of the children were obtained. Mercury levels were measured through analyzing fingernail samples. Logistic regression modeling the effect of risk factors on mercury levels above the 75(th percentile were made, adjusted for potential confounders.The 288 children had a mean age of 9.6 years (SD = 1.9. The mean mercury level in the study population was 0.13 µg/g (SD 0.11, median 0.10, range 0.001-0.86 µg/g. The strongest risk factor for children's odds of high mercury levels (>75(th percentile, 0.165 µg/g was to play inside a house where a family member worked with mercury (OR adjusted 3.49 95% CI 1.23-9.89. Additionally, children whose parents worked in industrial gold mining had higher odds of high mercury levels than children whose parents worked in industrial copper mining or outside mining activities.Mercury exposure through small-scale gold mining might affect children in their home environments. These results may further help to convince the local population of banning mercury burning inside the households.

  8. Health and environmental impact of mercury in the Philippines using nuclear techniques

    International Nuclear Information System (INIS)

    Cortex-Maramba, Nelia; Trinidad Francisco-Rivera, Ana; Manglicmot, Ailyn; Santos, Flora; Akagi, Hirokatsu

    2001-01-01

    Artisanal gold mining activities using mercury has proliferated in various parts of the country since the early 1980's. In Southern Philippines, it is estimated that a small-scale gold processor utilizes one kilogram of mercury every week or an average of fifty-two kgs./yr. Production is estimated at 30 kilograms of gold per day. It has been estimated that 140 tons of mercury flux have been dumped directly into the river systems from small-scale gold mining operations in one of the gold rush areas in the country. Small-scale mining operations have affected tributaries and water systems in the country that also relies heavily on fishing as a source of livelihood as well as the daily food fare among the low-income sectors in the area. Aside from this, cattle livestock and agricultural production have also been affected by these mining activities because of contamination of the irrigation and water systems. Presently, environmental and health monitoring conducted by several government agencies in the recent past were limited to the determination of total mercury only. Previous studies undertaken focused mainly on the exposure of adults and workers to mercury during mining/processing operations. Environmental quality monitoring showed total mercury sediment levels ranged from 0.55 ug/g dry weight while water samples from river systems exhibited mercury levels from 0.0728-0.0784 ppb. Fish samples collected showed levels ranging from 1.07-438.8 ppb for total mercury and 0.71-377.18 ppb for methyl mercury. Methyl mercury content in fish ranged from 56-99%. Laboratory results showed that total mercury hair samples in schoolchildren ranged from 0.278-20.393 ppm while methyl mercury levels were from 0.191-18.469 ppm. Methyl mercury represented 45.96%-99.81% of the total mercury levels in hair. Total blood mercury levels ranged from 0.757-56.88 ppb while methyl mercury blood levels ranged from 1.36-46.73 ppb. Summary of physical examination results showed that predominant

  9. Environmental and health aspects of lighting: Mercury

    Energy Technology Data Exchange (ETDEWEB)

    Clear, R.; Berman, S.

    1993-07-01

    Most discharge lamps, including fluorescent lamps, metal halide lamps, and high pressure sodium lamps, contain Mercury, a toxic chemical. Lighting professionals need to be able to respond to questions about the direct hazards of Mercury from accidentally breaking lamps, and the potential environmental hazards of lamp operation and disposal. We calculated the exposures that could occur from an accidental breakage of lamps. Acute poisoning appears almost impossible. Under some circumstances a sealed environment, such as a space station, could be contaminated enough to make it unhealthy for long-term occupation. Mercury becomes a potential environmental hazard after it becomes methylated. Mercury is methylated in aquatic environments, where it may accumulate in fish, eventually rendering them toxic to people and other animals. Lighting causes Mercury to enter the environment directly from lamp disposal, and indirectly from power plant emissions. The environmental tradeoffs between incandescent and discharge lamps depend upon the amounts released by these two sources, their local concentrations, and their probabilities of being methylated. Indirect environmental effects of lighting also include the release of other heavy metals (Cadmium, Lead and Arsenic), and other air pollutants and carbon dioxide that are emitted by fossil fuel power plants. For a given light output, the level of power plant emissions depends upon the efficacy of the light source, and is thus much larger for incandescent lamps than for fluorescent or discharge lamps. As disposal and control technologies change the relative direct and indirect emissions from discharge and incandescent lamps will change.

  10. Occupational Exposure to Mercury among Workers in a Fluorescent Lamp Factory, Quisna Industrial Zone, Egypt

    Directory of Open Access Journals (Sweden)

    MA Al-Batanony

    2013-07-01

    Full Text Available Background: With the fast growth in the market of fluorescent lamps, particularly compact fluorescent light, the associated risk of mercury exposure, which is an essential component in all types of fluorescent lamps, has received increasing public attention worldwide. Even low doses of mercury are toxic. Objective: To study the health consequences of occupational exposure to mercury in workers of a fluorescent lamp factory. Methods: In a cross-sectional study 138 workers of a florescent lamp factory and 151 people who had no occupational exposure to mercury (the comparison group were studied. Environmental study of mercury and noise levels was done. For all participants a neurobehavioral test battery was administered, spirometry was performed and air conduction audiometry was done. Urinary mercury level was also measured for all participants. Results: Prominent symptoms among workers exposed to mercury included tremors, emotional lability, memory changes, neuromuscular changes, and performance deficits in tests of cognitive function. Among the exposed group, the mean urinary mercury level was significantly higher in those who had personality changes or had manifestations of mercury toxicity. With increasing duration of employment and urinary mercury level, the performance of participants in neurobehavioral test battery and spirometric parameters deteriorated. Conclusion: Neurobehavioral test battery must be used for studying subclinical central nervous system dysfunction in those with chronic exposure to mercury. The test is especially useful for evaluating the severity of mercury effects in epidemiological studies. This study also reinforces the need for effective preventive programs for florescent lamp industry workplaces especially in developing countries with the lowest unhygienic work conditions.

  11. Chronic psychological effects of exposure to mercury vapour among chlorine-alkali plant workers.

    Science.gov (United States)

    Pranjić, N; Sinanović, O; Jakubović, R

    2003-01-01

    Quantitative assessment of nervous system function is essential in characterising the nature and extent of impairment in individuals experiencing symptoms following work-place mercury vapour exposure. The purpose of this study was the application of standardised tests of behavioural, psychomotor and memory function to understand the neuropsychological effects of mercury in occupationally exposed chlorine-alkali plant workers. The study comprised 45 workers at a chlorine-alkali plant with the mean age of 39.36 +/- 5.94 years, who had been exposed to daily inhalation of mercury vapour over long-term employment of 16.06 +/- 4.29 years. The cumulative mercury index was 155.32 +/- 95.02 micrograms/g creatinine, the mean of urinary mercury concentrations on the first day of the study was 119.50 +/- 157.24 micrograms/g creatinine, and the mean of urinary mercury concentrations 120 days after cessation of exposure was 21.70 +/- 26.07 micrograms/g creatinine. The analysis included tests of behavioural, psychomotor and memory function. The behavioural test battery consisted of: Environmental Worry Scale (EWS), Minnesota Modified Personal Inventory (MMPI-2), Purdue standard 25 minute test, and adapted, 10 minutes test, Bender's Visual-Motor Gestalt test (BGT), and Eysenck Personality Inventory (EPQ). The data were compared to a control group of 32 not directly exposed workers. In the mercury vapour exposed workers with relatively high level exposure to inorganic mercury vapour (TWA/TLV = 0.12 mg/m3/0.025 mg/m3) we identified somatic depression-hypochondria symptoms with higher scores for scales: hysteria (P introvert behaviour (EPQ, MMPI-2). The cognitive disturbances in mercury-exposed workers were identified as: concentration difficulty, psychomotor, perceptual and motor coordination disturbances, and brain effects. We identified fine tremor of the hands in 34 out of 45 mercury-exposed workers (BGT). The results point to a relationship between the duration of mercury

  12. Exposure to mercury among Spanish preschool children: Trend from birth to age four

    Energy Technology Data Exchange (ETDEWEB)

    Llop, Sabrina, E-mail: llop_sab@gva.es [Foundation for the Promotion of Health and Biomedical Research in the Valencian Region, FISABIO-Public Health, Av. Catalunya 21, 46020 Valencia (Spain); Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Murcia, Mario [Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Foundation for the Promotion of Health and Biomedical Research in the Valencian Region, FISABIO-Public Health, Av. Catalunya 21, 46020 Valencia (Spain); Aguinagalde, Xabier [Laboratorio de Salud Pública de Alava, Santiago 11, 01002 Vitoria Gasteiz (Spain); Vioque, Jesus [Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Universidad Miguel Hernandez, Avenida de Alicante KM 87, 03550 Sant Joan d´Alacant (Spain); Rebagliato, Marisa [Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Medicine Department, Jaume I University, Av. Vicent Sos Baynat, s/n, 12071 Castelló de la Plana (Spain); Cases, Amparo [Foundation for the Promotion of Health and Biomedical Research in the Valencian Region, FISABIO-Public Health, Av. Catalunya 21, 46020 Valencia (Spain); Iñiguez, Carmen; Lopez-Espinosa, Maria-Jose [Foundation for the Promotion of Health and Biomedical Research in the Valencian Region, FISABIO-Public Health, Av. Catalunya 21, 46020 Valencia (Spain); Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Amurrio, Ascensión [Laboratorio de Salud Pública de Alava, Santiago 11, 01002 Vitoria Gasteiz (Spain); María Navarrete-Muñoz, Eva [Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Universidad Miguel Hernandez, Avenida de Alicante KM 87, 03550 Sant Joan d´Alacant (Spain); and others

    2014-07-15

    The purpose of this study is to describe the total hair mercury concentrations and their determinants in preschool Spanish children, as well as to explore the trend in mercury exposure from birth to the age four. This evolution has been scarcely studied in other birth cohort studies. The study population was 580 four year old children participating in the INMA (i.e. Childhood and Environment) birth cohort study in Valencia (2008–2009). Total mercury concentration at age four was measured in hair samples by atomic absorption spectrometry. Fish consumption and other covariates were obtained by questionnaire. Multivariate linear regression models were conducted in order to explore the association between mercury exposure and fish consumption, socio-demographic characteristics and prenatal exposure to mercury. The geometric mean was 1.10 µg/g (95%CI: 1.02, 1.19). Nineteen percent of children had mercury concentrations above the equivalent to the Provisional Tolerable Weekly Intake proposed by WHO. Mercury concentration was associated with increasing maternal age, fish consumption and cord blood mercury levels, as well as decreasing parity. Children whose mothers worked had higher mercury levels than those with non working mothers. Swordfish, lean fish and canned fish were the fish categories most associated with hair mercury concentrations. We observed a decreasing trend in mercury concentrations between birth and age four. In conclusion, the children participating in this study had high hair mercury concentrations compared to reported studies on children from other European countries and similar to other countries with high fish consumption. The INMA study design allows the evaluation of the exposure to mercury longitudinally and enables this information to be used for biomonitoring purposes and dietary recommendations. - Highlights: • The geometric mean of hair Hg concentrations was 1.10 µg/g. • 19% of children had Hg concentrations above the RfD proposed by

  13. Exposure to mercury among Spanish preschool children: Trend from birth to age four

    International Nuclear Information System (INIS)

    Llop, Sabrina; Murcia, Mario; Aguinagalde, Xabier; Vioque, Jesus; Rebagliato, Marisa; Cases, Amparo; Iñiguez, Carmen; Lopez-Espinosa, Maria-Jose; Amurrio, Ascensión; María Navarrete-Muñoz, Eva

    2014-01-01

    The purpose of this study is to describe the total hair mercury concentrations and their determinants in preschool Spanish children, as well as to explore the trend in mercury exposure from birth to the age four. This evolution has been scarcely studied in other birth cohort studies. The study population was 580 four year old children participating in the INMA (i.e. Childhood and Environment) birth cohort study in Valencia (2008–2009). Total mercury concentration at age four was measured in hair samples by atomic absorption spectrometry. Fish consumption and other covariates were obtained by questionnaire. Multivariate linear regression models were conducted in order to explore the association between mercury exposure and fish consumption, socio-demographic characteristics and prenatal exposure to mercury. The geometric mean was 1.10 µg/g (95%CI: 1.02, 1.19). Nineteen percent of children had mercury concentrations above the equivalent to the Provisional Tolerable Weekly Intake proposed by WHO. Mercury concentration was associated with increasing maternal age, fish consumption and cord blood mercury levels, as well as decreasing parity. Children whose mothers worked had higher mercury levels than those with non working mothers. Swordfish, lean fish and canned fish were the fish categories most associated with hair mercury concentrations. We observed a decreasing trend in mercury concentrations between birth and age four. In conclusion, the children participating in this study had high hair mercury concentrations compared to reported studies on children from other European countries and similar to other countries with high fish consumption. The INMA study design allows the evaluation of the exposure to mercury longitudinally and enables this information to be used for biomonitoring purposes and dietary recommendations. - Highlights: • The geometric mean of hair Hg concentrations was 1.10 µg/g. • 19% of children had Hg concentrations above the RfD proposed by

  14. A review of mercury exposure among artisanal small-scale gold miners in developing countries

    DEFF Research Database (Denmark)

    Kristensen, Anders Kasper Bruun; Thomsen, Jane Frølund; Mikkelsen, Sigurd

    2014-01-01

    Extraction of gold using mercury has been a way out of poverty for millions of people in developing countries. Artisanal small-scale gold mining (ASGM) has expanded during the last decades and is often carried out under primitive conditions. Thus, workers in this industry may be exposed to high...... levels of mercury and suffer from toxic effects from mercury exposure. The objective of this review was to provide an outline of the studies available on elemental mercury exposure among artisanal small-scale gold miners....

  15. Mercury kinetics in marine zooplankton

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  16. Exposure to low mercury concentration in vivo impairs myocardial contractile function

    International Nuclear Information System (INIS)

    Furieri, Lorena Barros; Fioresi, Mirian; Junior, Rogerio Faustino Ribeiro; Bartolome, Maria Visitacion; Fernandes, Aurelia Araujo; Cachofeiro, Victoria; Lahera, Vicente; Salaices, Mercedes; Stefanon, Ivanita; Vassallo, Dalton Valentim

    2011-01-01

    Increased cardiovascular risk after mercury exposure has been described but cardiac effects resulting from controlled chronic treatment are not yet well explored. We analyzed the effects of chronic exposure to low mercury concentrations on hemodynamic and ventricular function of isolated hearts. Wistar rats were treated with HgCl 2 (1st dose 4.6 μg/kg, subsequent dose 0.07 μg/kg/day, im, 30 days) or vehicle. Mercury treatment did not affect blood pressure (BP) nor produced cardiac hypertrophy or changes of myocyte morphometry and collagen content. This treatment: 1) in vivo increased left ventricle end diastolic pressure (LVEDP) without changing left ventricular systolic pressure (LVSP) and heart rate; 2) in isolated hearts reduced LV isovolumic systolic pressure and time derivatives, and β-adrenergic response; 3) increased myosin ATPase activity; 4) reduced Na + -K + ATPase (NKA) activity; 5) reduced protein expression of SERCA and phosphorylated phospholamban on serine 16 while phospholamban expression increased; as a consequence SERCA/phospholamban ratio reduced; 6) reduced sodium/calcium exchanger (NCX) protein expression and α-1 isoform of NKA, whereas α-2 isoform of NKA did not change. Chronic exposure for 30 days to low concentrations of mercury does not change BP, heart rate or LVSP but produces small but significant increase of LVEDP. However, in isolated hearts mercury treatment promoted contractility dysfunction as a result of the decreased NKA activity, reduction of NCX and SERCA and increased PLB protein expression. These findings offer further evidence that mercury chronic exposure, even at small concentrations, is an environmental risk factor affecting heart function. - Highlights: → Unchanges blood pressure, heart rate, systolic pressure. → Increases end diastolic pressure. → Promotes cardiac contractility dysfunction. → Decreases NKA activity, NCX and SERCA, increases PLB protein expression. → Small concentrations constitutes

  17. [Current dietary exposure to mercury during pregnancy and childhood, and public health recommendations].

    Science.gov (United States)

    Llop, Sabrina; Ibarlucea, Jesús; Sunyer, Jordi; Ballester, Ferran

    2013-01-01

    Exposure to high levels of mercury during vulnerable periods (such as pregnancy and childhood) may have serious consequences for cognitive development, as observed after acute poisoning episodes in Japan and Irak. The main source of mercury exposure in the general population is consumption of certain types of fish. There is growing concern about the possible neurotoxic effects of mercury, especially in younger children in populations where fish intake is moderate to high. The scientific evidence to date is inconclusive. In Spain, the Childhood and Environment (Infancia y Medio Ambiente [INMA]) project has provided information on levels of prenatal exposure to mercury among 1800 newborns from Valencia, Sabadell, Asturias and Guipúzcoa. In general, levels were high, being above the World Health Organization's recommended dose in 24% of children and above the recommended levels of the U.S. Environmental Protection Agency in 64%. However, the results did not indicate a significant association between prenatal mercury exposure and delayed cognitive development during the second year of life. Various agencies have developed recommendations on fish consumption for pregnant women and children, due to the presence of mercury. These recommendations should be strengthened, since there is general consensus among all regional and national public administrations that fish is an essential source of nutrients for development in the early stages of life. Copyright © 2012 SESPAS. Published by Elsevier Espana. All rights reserved.

  18. Co-ordinated research project on health impacts of mercury cycling in contaminated environments studied by nuclear techniques. Report on the first research co-ordination meeting

    International Nuclear Information System (INIS)

    2001-01-01

    The specific research objective of this coordinated research project is to study and assess the factors influencing the dynamics of Hg cycling and its impact on human health in mercury contaminated ecosystems, especially in tropical environments, using radioisotopes and enriched stable isotope tracers and/or complementary analytical techniques. Areas of research include: Evaluation of the relevant environmental factors influencing mercury transformations, transportation (mass balances), and partitioning in ecosystems; Development, validation and application of appropriate methodologies for the measurement of Hg methylation and de-methylation rates in various environmental compartments; Development, validation and application of appropriate methodologies for the measurement of Hg fluxes at natural interfaces such as sediment-water, water-air, land-air, plant-air, and saline-water-fresh-water, etc.; Determination and evaluation of the human exposure to Hg using bio-indicators such as hair, blood, and urine in light of epidemiological requirements; Preparation of an appropriate test sample of tropical sediment for comparability studies. Expected research outputs are: Recommended approaches for the determination of mercury methylation and de-methylation rates and flux measurements; A compilation of reliable data on mercury methylation and de-methylation rates and fluxes in contaminated tropical ecosystems for comparison with existing data from temperate regions; Generated knowledge on factors influencing mercury transformations, transport and partitioning in various ecosystems; Test sample of tropical sediment for comparability studies; Database of bio-indicator measurements (hair, blood, and urine, etc.) of human Hg exposure in contaminated tropical ecosystems; and Recommended countermeasures for the prevention and/or reduction of mercury contamination in polluted areas

  19. Co-ordinated research project on health impacts of mercury cycling in contaminated environments studied by nuclear techniques. Report on the first research co-ordination meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The specific research objective of this coordinated research project is to study and assess the factors influencing the dynamics of Hg cycling and its impact on human health in mercury contaminated ecosystems, especially in tropical environments, using radioisotopes and enriched stable isotope tracers and/or complementary analytical techniques. Areas of research include: Evaluation of the relevant environmental factors influencing mercury transformations, transportation (mass balances), and partitioning in ecosystems; Development, validation and application of appropriate methodologies for the measurement of Hg methylation and de-methylation rates in various environmental compartments; Development, validation and application of appropriate methodologies for the measurement of Hg fluxes at natural interfaces such as sediment-water, water-air, land-air, plant-air, and saline-water-fresh-water, etc.; Determination and evaluation of the human exposure to Hg using bio-indicators such as hair, blood, and urine in light of epidemiological requirements; Preparation of an appropriate test sample of tropical sediment for comparability studies. Expected research outputs are: Recommended approaches for the determination of mercury methylation and de-methylation rates and flux measurements; A compilation of reliable data on mercury methylation and de-methylation rates and fluxes in contaminated tropical ecosystems for comparison with existing data from temperate regions; Generated knowledge on factors influencing mercury transformations, transport and partitioning in various ecosystems; Test sample of tropical sediment for comparability studies; Database of bio-indicator measurements (hair, blood, and urine, etc.) of human Hg exposure in contaminated tropical ecosystems; and Recommended countermeasures for the prevention and/or reduction of mercury contamination in polluted areas.

  20. Below a Historic Mercury Mine: Non-linear Patterns of Mercury Bioaccumulation in Aquatic Organisms

    Science.gov (United States)

    Haas, J.; Ichikawa, G.; Ode, P.; Salsbery, D.; Abel, J.

    2001-12-01

    Unlike most heavy metals, mercury is capable of bioaccumulating in aquatic food-chains, primarily because it is methylated by bacteria in sediment to the more toxic methylmercury form. Mercury concentrations in a number of riparian systems in California are highly elevated as a result of historic mining activities. These activities included both the mining of cinnabar in the coastal ranges to recover elemental mercury and the use of elemental mercury in the gold fields of the Sierra Nevada Mountains. The most productive mercury mining area was the New Almaden District, now a county park, located in the Guadalupe River drainage of Santa Clara County, where cinnabar was mined and retorted for over 100 years. As a consequence, riparian systems in several subwatersheds of the Guadalupe River drainage are contaminated with total mercury concentrations that exceed state hazardous waste criteria. Mercury concentrations in fish tissue frequently exceed human health guidelines. However, the potential ecological effects of these elevated mercury concentrations have not been thoroughly evaluated. One difficulty is in extrapolating sediment concentrations to fish tissue concentrations without accounting for physical and biological processes that determine bioaccumulation patterns. Many processes, such as methylation and demethylation of mercury by bacteria, assimilation efficiency in invertebrates, and metabolic rates in fish, are nonlinear, a factor that often confounds attempts to evaluate the effects of mercury contamination on aquatic food webs. Sediment, benthic macroinvertebrate, and fish tissue samples were collected in 1998 from the Guadalupe River drainage in Santa Clara County at 13 sites upstream and downstream from the historic mining district. Sediment and macroinvertebrate samples were analyzed for total mercury and methylmercury. Fish samples were analyzed for total mercury as whole bodies, composited by species and size. While linear correlations of sediment

  1. Genetic effects of organic mercury compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ramel, C

    1967-01-01

    Organic mercury compounds have a c-mitotic effect on plant cells that cause polyploidi. Studies were performed on Allium root cells. These investigations involved methyl mercury dicyandiamide, methyl mercury hydroxide, and phenyl mercury hydroxide. The lowest concentration necessary for a cytologically observable effect was about 0.05 ppM Hg for the methyl compounds. For the phenyl compound, the value was lower. Experiments were performed on Drosophila melanogaster. The question was whether the mercury would reach the gonads. Experimental data with mercury treated larvae indicated a chromosome disjunction. Data indicated a preferential segregation at the meiotic division might be involved. Experiments are being performed on mice inbred (CBA) in order to investigate teratogenic effects and dominant lethality caused by organic mercury compounds. The mutagenic effects of these compounds are studied on Neurospora Drosophila. No conclusive data is now available.

  2. Mercury Biogeochemical Cycling in the Ocean and Policy Implications

    OpenAIRE

    Mason, Robert P.; Choi, Anna L.; Fitzgerald, William F.; Hammerschmidt, Chad R.; Lamborg, Carl H.; Soerensen, Anne L.; Sunderland, Elsie M.

    2012-01-01

    Anthropogenic activities have enriched mercury in the biosphere by at least a factor of three, leading to increases in total mercury (Hg) in the surface ocean. However, the impacts on ocean fish and associated trends in human exposure as a result of such changes are less clear. Here we review our understanding of global mass budgets for both inorganic and methylated Hg species in ocean seawater. We consider external inputs from atmospheric deposition and rivers as well as internal production ...

  3. Geographic and seasonal variation in mercury exposure of the declining Rusty Blackbird

    Science.gov (United States)

    Samuel T. Edmonds; David C. Evers; Daniel A. Cristol; Claudia Mettke-Hofmann; Luke L. Powell

    2010-01-01

    Recent evidence suggests that mercury exposure has negative effects on the health of songbirds, and species that forage in wetlands may be at a greater risk of bioaccumulation of mercury than are those of other habitats. We examined mercury concentrations in blood and feathers from the wetland obligate and rapidly declining Rusty Blackbird (Euphagus carolinus) from...

  4. Mercury Exposure and Risk of Cardiovascular Disease in Two U.S. Cohorts

    Science.gov (United States)

    Mozaffarian, Dariush; Shi, Peilin; Morris, J. Steven; Spiegelman, Donna; Grandjean, Philippe; Siscovick, David S.; Willett, Walter C.; Rimm, Eric B.

    2011-01-01

    BACKGROUND Exposure to methylmercury from fish consumption has been linked to a potentially increased risk of cardiovascular disease, but evidence from prior studies is equivocal. Beneficial effects of the ingestion of fish and selenium may also modify such effects. METHODS Among subjects from two U.S. cohorts (a total of 51,529 men and 121,700 women) whose toenail clippings had been stored, we prospectively identified incident cases of cardiovascular disease (coronary heart disease and stroke) in 3427 participants and matched them to risk-set–sampled controls according to age, sex, race, and smoking status. Toenail mercury and selenium concentrations were assessed with the use of neutron-activation analysis. Other demographic characteristics, cardiovascular risk factors, fish consumption, and lifestyle habits were assessed by means of validated questionnaires. Associations between mercury exposure and incident cardiovascular disease were evaluated with the use of conditional logistic regression. RESULTS Median toenail mercury concentrations were 0.23 µg per gram (interdecile range, 0.06 to 0.94) in the case participants and 0.25 µg per gram (interdecile range, 0.07 to 0.97) in the controls. In multivariate analyses, participants with higher mercury exposures did not have a higher risk of cardiovascular disease. For comparisons of the fifth quintile of mercury exposure with the first quintile, the relative risks were as follows: coronary heart disease, 0.85 (95% confidence interval [CI], 0.69 to 1.04; P = 0.10 for trend); stroke, 0.84 (95% CI, 0.62 to 1.14; P = 0.27 for trend); and total cardiovascular disease, 0.85 (95% CI, 0.72 to 1.01; P = 0.06 for trend). Findings were similar in analyses of participants with low selenium concentrations or low overall fish consumption and in several additional sensitivity analyses. CONCLUSIONS We found no evidence of any clinically relevant adverse effects of mercury exposure on coronary heart disease, stroke, or total

  5. Mercury use and exposure among Santeria practitioners: religious versus folk practice in Northern New Jersey, USA.

    Science.gov (United States)

    Alison Newby, C; Riley, Donna M; Leal-Almeraz, Tomás O

    2006-08-01

    To understand and characterize exposure to and use of elemental mercury among practitioners of Afro-Cuban religions in Hudson County, New Jersey, USA. Participant observation and open-ended interviews with 22 religious supply store employees and practitioners of Santeria, Espiritismo or Palo Mayombe probed respondents' knowledge and use of mercury, as well as their beliefs about its benefits and risks. Including a cultural and religious insider as part of the research team was crucial in working with this relatively closed community. Seventeen of the 21 practitioners reported using mercury or mercury compounds in various forms of practice and in services that they provide to clients. The contained nature of these uses suggests that accidental spills, as opposed to the practices themselves, emerge as the greatest exposure concern for this population. Mercury was never recommended to clients for individual use. This restriction appears to be rooted in the way the religion is practiced and in the way santeros receive compensation, not in a perception of mercury as hazardous. Most practitioners were aware that mercury can be hazardous, but were not familiar with the most significant exposure pathway, inhalation of mercury vapor. A climate of fear surrounds the use of mercury in this community, so that health concerns pale in comparison to fear of reprisal from authorities. Among those who sell or formerly sold mercury, several shared the erroneous belief that it was illegal to sell mercury in New Jersey. Despite widespread reported use, there were no reports of practices believed to result in the highest exposures. To reduce exposure in the community, interventions presenting general information on mercury hazards and instructions for cleaning up spills are recommended. To address insider-outsider dynamics and the climate of fear, educational materials should be accessible to the community and avoid any mention of religious practice.

  6. Phytoremediation of Ionic and Methyl Mercury Pollution

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, Richard B.

    2004-12-01

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

  7. Assessment of mercury exposure among small-scale gold miners using mercury stable isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Laura S., E-mail: lsaylors@umich.edu [University of Michigan, Department of Earth and Environmental Sciences, 1100 North University Avenue, Ann Arbor, MI 48109 (United States); Blum, Joel D. [University of Michigan, Department of Earth and Environmental Sciences, 1100 North University Avenue, Ann Arbor, MI 48109 (United States); Basu, Niladri [McGill University, Faculty of Agricultural and Environmental Sciences, 21,111 Lakeshore Road, Ste. Anne de Bellevue, Quebec, Canada H9X3V9 (Canada); Rajaee, Mozhgon [University of Michigan, Department of Environmental Health Sciences, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Evers, David C.; Buck, David G. [Biodiversity Research Institute, 19 Flaggy Meadow Road, Gorham, ME 04038 (United States); Petrlik, Jindrich [Arnika Association, Chlumova 17, Prague 3 (Czech Republic); DiGangi, Joseph [IPEN, Box 7256, SE-402 35 Gothenburg (Sweden)

    2015-02-15

    Total mercury (Hg) concentrations in hair and urine are often used as biomarkers of exposure to fish-derived methylmercury (MeHg) and gaseous elemental Hg, respectively. We used Hg stable isotopes to assess the validity of these biomarkers among small-scale gold mining populations in Ghana and Indonesia. Urine from Ghanaian miners displayed similar Δ{sup 199}Hg values to Hg derived from ore deposits (mean urine Δ{sup 199}Hg=0.01‰, n=6). This suggests that urine total Hg concentrations accurately reflect exposure to inorganic Hg among this population. Hair samples from Ghanaian miners displayed low positive Δ{sup 199}Hg values (0.23–0.55‰, n=6) and low percentages of total Hg as MeHg (7.6–29%, n=7). These data suggest that the majority of the Hg in these miners' hair samples is exogenously adsorbed inorganic Hg and not fish-derived MeHg. Hair samples from Indonesian gold miners who eat fish daily displayed a wider range of positive Δ{sup 199}Hg values (0.21–1.32‰, n=5) and percentages of total Hg as MeHg (32–72%, n=4). This suggests that total Hg in the hair samples from Indonesian gold miners is likely a mixture of ingested fish MeHg and exogenously adsorbed inorganic Hg. Based on data from both populations, we suggest that total Hg concentrations in hair samples from small-scale gold miners likely overestimate exposure to MeHg from fish consumption. - Highlights: • Mercury isotopes were measured in hair and urine from small-scale gold miners. • Mercury isotopes indicate that Hg in urine comes from mining activity. • Mercury isotopes suggest Hg in hair is a mixture of fish MeHg and inorganic Hg. • A large percentage of Hg in miner’s hair is released during amalgam burning and adsorbed.

  8. Phytoremediation of Ionic and Methyl Mercury Pollution

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, Richard B.

    2005-06-01

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

  9. Mercury exposure may influence fluctuating asymmetry in waterbirds.

    Science.gov (United States)

    Herring, Garth; Eagles-Smith, Collin A; Ackerman, Joshua T

    2017-06-01

    Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds. Environ Toxicol Chem 2017;36:1599-1605. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

  10. Co-ordinated research project on health impacts of mercury cycling in contaminated environments studied by nuclear techniques. Report on the second research co-ordination meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    The specific research objective of this coordinated research project is to study and assess the factors influencing the dynamics of Hg cycling and its impact on human health in mercury contaminated ecosystems, especially in tropical environments, using radioisotopes and enriched stable isotope tracers and/or complementary analytical techniques. Areas of research include: Evaluation of the relevant environmental factors influencing mercury transformations, transportation (mass balances), and partitioning in ecosystems; Development, validation and application of appropriate methodologies for the measurement of Hg methylation and de-methylation rates in various environmental compartments; Development, validation and application of appropriate methodologies for the measurement of Hg fluxes at natural interfaces such as sediment-water, water-air, land-air, plant-air, and saline-water-fresh-water, etc.; Determination and evaluation of the human exposure to Hg using bio-indicators such as hair, blood, and urine in light of epidemiological requirements; Preparation of an appropriate test sample of tropical sediment for comparability studies. Expected research outputs are: Recommended approaches for the determination of mercury methylation and de-methylation rates and flux measurements; A compilation of reliable data on mercury methylation and de-methylation rates and fluxes in contaminated tropical ecosystems for comparison with existing data from temperate regions; Generated knowledge on factors influencing mercury transformations, transport and partitioning in various ecosystems; Test sample of tropical sediment for comparability studies; Database of bio-indicator measurements (hair, blood, and urine, etc.) of human Hg exposure in contaminated tropical ecosystems; and Recommended countermeasures for the prevention and/or reduction of mercury contamination in polluted areas. This compilation contains country reports on the Second Research Coordination Meeting, Minamata

  11. Co-ordinated research project on health impacts of mercury cycling in contaminated environments studied by nuclear techniques. Report on the second research co-ordination meeting

    International Nuclear Information System (INIS)

    2002-01-01

    The specific research objective of this coordinated research project is to study and assess the factors influencing the dynamics of Hg cycling and its impact on human health in mercury contaminated ecosystems, especially in tropical environments, using radioisotopes and enriched stable isotope tracers and/or complementary analytical techniques. Areas of research include: Evaluation of the relevant environmental factors influencing mercury transformations, transportation (mass balances), and partitioning in ecosystems; Development, validation and application of appropriate methodologies for the measurement of Hg methylation and de-methylation rates in various environmental compartments; Development, validation and application of appropriate methodologies for the measurement of Hg fluxes at natural interfaces such as sediment-water, water-air, land-air, plant-air, and saline-water-fresh-water, etc.; Determination and evaluation of the human exposure to Hg using bio-indicators such as hair, blood, and urine in light of epidemiological requirements; Preparation of an appropriate test sample of tropical sediment for comparability studies. Expected research outputs are: Recommended approaches for the determination of mercury methylation and de-methylation rates and flux measurements; A compilation of reliable data on mercury methylation and de-methylation rates and fluxes in contaminated tropical ecosystems for comparison with existing data from temperate regions; Generated knowledge on factors influencing mercury transformations, transport and partitioning in various ecosystems; Test sample of tropical sediment for comparability studies; Database of bio-indicator measurements (hair, blood, and urine, etc.) of human Hg exposure in contaminated tropical ecosystems; and Recommended countermeasures for the prevention and/or reduction of mercury contamination in polluted areas. This compilation contains country reports on the Second Research Coordination Meeting, Minamata

  12. Impact of exposure to low levels of mercury on the health of dental workers

    Directory of Open Access Journals (Sweden)

    Leda Freitas Jesus

    2016-09-01

    Full Text Available This work evaluated the impact of exposure to mercury on the health of workers comparing dentists and dental assistants exposed to mercury by handling amalgam in a public dental clinic with a reference group which, in private offices, did not make use of the metal in their professional routine. Data collection included mercury levels in urine and air samples determined by cold vapor atomic absorption spectrometry, questionnaires and direct observation. The difference between urine and air samples in both groups was statistically significant while mercury levels in air and urine showed positive associations. Mercury concentration in urine correlated with gender, practice time, and age of workers. Half of those exposed had complaints compatible with mercury contamination. Among the exposed, the most common complaints were cognitive and neurocognitive symptoms. Correlations between symptoms and exposure time and also number of amalgam fillings placed per week were positive. Amalgam handling resulted in environmental and biological contamination by mercury.

  13. Identifying Key Proteins in Hg Methylation Pathways of Desulfovibrio by Global Proteomics, Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Summers, Anne O. [Univ. of Georgia, Athens, GA (United States). Dept. of Microbiology; Miller, Susan M. [Univ. of California, San Francisco, CA (United States). Dept. of Pharmaceutical Chemistry; Wall, Judy [Univ. of Missouri, Columbia, MO (United States). Dept. of Biochemistry; Lipton, Mary [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-06-18

    Elemental mercury, Hg(0) is a contaminant at many DOE sites, especially at Oak Ridge National Laboratory (ORNL) where the spread of spilled Hg and its effects on microbial populations have been monitored for decades. To explore the microbial interactions with Hg, we have devised a global proteomic approach capable of directly detecting Hg-adducts of proteins. This technique developed in the facultative anaerobe, Escherichia coli, allows us to identify the proteins most vulnerable to acute exposure to organomercurials phenyl- and ethyl-mercury (as surrogates for the highly neurotoxic methyl-Hg) (Polacco, et al, 2011). We have found >300 such proteins in all metabolic functional groups and cellular compartments; most are highly conserved and can serve as markers for acute Hg exposure (Zink, et al. 2016, in preparation). We have also discovered that acute Hg exposure severely disrupts thiol, iron and redox homeostases, and electrolyte balance (LaVoie, et al., 2015) Thus, we proposed to bring these techniques to bear on the central problem of identifying the cellular proteins involved in bacterial uptake and methylation of mercury and its release from the cell.

  14. Influences on Mercury Bioaccumulation Factors for the Savannah River

    International Nuclear Information System (INIS)

    Paller, M.H.

    2003-01-01

    Mercury TMDLs (Total Maximum Daily Loads) are a regulatory instrument designed to reduce the amount of mercury entering a water body and ultimately to control the bioaccumulation of mercury in fish. TMDLs are based on a BAF (bioaccumulation factor), which is the ratio of methyl mercury in fish to dissolved methyl mercury in water. Analysis of fish tissue and aqueous methyl mercury samples collected at a number of locations and over several seasons in a 118 km reach of the Savannah River demonstrated that species specific BAFs varied by factors of three to eight. Factors contributing to BAF variability were location, habitat and season related differences in fish muscle tissue mercury levels and seasonal differences in dissolved methyl mercury levels. Overall (all locations, habitats, and seasons) average BAFs were 3.7 x 106 for largemouth bass, 1.4 x 106 for sunfishes, and 2.5 x 106 for white catfish. Inaccurate and imprecise BAFs can result in unnecessary economic impact or insufficient protection of human health. Determination of representative and precise BAFs for mercury in fish FR-om large rivers necessitates collecting large and approximately equal numbers of fish and aqueous methyl mercury samples over a seasonal cycle FR-om the entire area and all habitats to be represented by the TMDL

  15. Aerobic Mercury-resistant bacteria alter Mercury speciation and retention in the Tagus Estuary (Portugal).

    Science.gov (United States)

    Figueiredo, Neusa L; Canário, João; O'Driscoll, Nelson J; Duarte, Aida; Carvalho, Cristina

    2016-02-01

    Aerobic mercury-resistant bacteria were isolated from the sediments of two highly mercury-polluted areas of the Tagus Estuary (Barreiro and Cala do Norte) and one natural reserve area (Alcochete) in order to test their capacity to transform mercury. Bacterial species were identified using 16S rRNA amplification and sequencing techniques and the results indicate the prevalence of Bacillus sp. Resistance patterns to mercurial compounds were established by the determination of minimal inhibitory concentrations. Representative Hg-resistant bacteria were further tested for transformation pathways (reduction, volatilization and methylation) in cultures containing mercury chloride. Bacterial Hg-methylation was carried out by Vibrio fluvialis, Bacillus megaterium and Serratia marcescens that transformed 2-8% of total mercury into methylmercury in 48h. In addition, most of the HgR bacterial isolates showed Hg(2+)-reduction andHg(0)-volatilization resulting 6-50% mercury loss from the culture media. In summary, the results obtained under controlled laboratory conditions indicate that aerobic Hg-resistant bacteria from the Tagus Estuary significantly affect both the methylation and reduction of mercury and may have a dual face by providing a pathway for pollution dispersion while forming methylmercury, which is highly toxic for living organisms. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Got Mercury?

    Science.gov (United States)

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

    2009-01-01

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

  17. Neuropsychological alterations in mercury intoxication persist several years after exposure

    Directory of Open Access Journals (Sweden)

    Elaine Cristina Zachi

    Full Text Available Abstract Elemental mercury is a liquid toxic metal widely used in industry. Occupational exposure occurs mainly via inhalation. Previously, neuropsychological assessment detected deficits in former workers of a fluorescent lamp plant who had been exposed to elemental mercury vapor and were away from exposure for several years at the time of examination. Objectives: The purpose of this work was to reexamine these functions after 18 months in order to evaluate their progression. Methods: Thirteen participants completed tests of attention, inhibitory control, verbal/visual memory, psychomotor speed, verbal fluency, visuomotor ability, executive function, semantic knowledge, and depression and anxiety inventories on 2 separate occasions. Results: At baseline, the former workers indicated slower psychomotor and information processing speed, verbal spontaneous recall memory impairment, and increased depression and anxiety symptoms compared to controls (P<0.05. Paired comparisons of neuropsychological functioning within the exposed group at baseline and 1.5 years later showed poorer immediate memory performance (P<0.05. There were no differences on other measures. Conclusions: Although the literature show signs of recovery of functions, the neuropsychological effects related to mercury exposure are found to persist for many years.

  18. Mercury in Nelson's Sparrow subspecies at breeding sites.

    Directory of Open Access Journals (Sweden)

    Virginia L Winder

    Full Text Available BACKGROUND: Mercury is a persistent, biomagnifying contaminant that can cause negative effects on ecosystems. Marshes are often areas of relatively high mercury methylation and bioaccumulation. Nelson's Sparrows (Ammodramus nelsoni use marsh habitats year-round and have been documented to exhibit tissue mercury concentrations that exceed negative effects thresholds. We sought to further characterize the potential risk of Nelson's Sparrows to mercury exposure by sampling individuals from sites within the range of each of its subspecies. METHODOLOGY/PRINCIPAL FINDINGS: From 2009 to 2011, we captured adult Nelson's Sparrows at sites within the breeding range of each subspecies (A. n. nelsoni: Grand Forks and Upham, North Dakota; A. n. alterus: Moosonee, Ontario; and A. n. subvirgatus: Grand Manan Island, New Brunswick and sampled breast feathers, the first primary feather (P1, and blood for total mercury analysis. Mean blood mercury in nelsoni individuals captured near Grand Forks ranged from 0.84 ± 0.37 to 1.65 ± 1.02 SD ppm among years, between 2.0 and 4.9 times as high as concentrations at the other sites (P<0.01. Breast feather mercury did not vary among sites within a given sampling year (site means ranged from 0.98 ± 0.69 to 2.71 ± 2.93 ppm. Mean P1 mercury in alterus (2.96 ± 1.84 ppm fw was significantly lower than in any other sampled population (5.25 ± 2.24-6.77 ± 3.51 ppm; P ≤ 0.03. CONCLUSIONS/SIGNIFICANCE: Our study further characterized mercury in Nelson's Sparrows near Grand Forks; we documented localized and potentially harmful mercury concentrations, indicating that this area may represent a biological mercury hotspot. This finding warrants further research to determine if wildlife populations of conservation or recreational interest in this area may be experiencing negative effects due to mercury exposure. We present preliminary conclusions about the risk of each sampled population to mercury exposure.

  19. Exposure to Inorganic Mercury Causes Oxidative Stress, Cell Death, and Functional Deficits in the Motor Cortex.

    Science.gov (United States)

    Teixeira, Francisco B; de Oliveira, Ana C A; Leão, Luana K R; Fagundes, Nathália C F; Fernandes, Rafael M; Fernandes, Luanna M P; da Silva, Márcia C F; Amado, Lilian L; Sagica, Fernanda E S; de Oliveira, Edivaldo H C; Crespo-Lopez, Maria E; Maia, Cristiane S F; Lima, Rafael R

    2018-01-01

    Mercury is a toxic metal that can be found in the environment in three different forms - elemental, organic and inorganic. Inorganic mercury has a lower liposolubility, which results in a lower organism absorption and reduced passage through the blood-brain barrier. For this reason, exposure models that use inorganic mercury in rats in order to evaluate its effects on the central nervous system are rare, especially in adult subjects. This study investigated if a chronic exposure to low doses of mercury chloride (HgCl2), an inorganic form of mercury, is capable of promoting motor alterations and neurodegenerative in the motor cortex of adult rats. Forty animals were exposed to a dose of 0.375 mg/kg/day, for 45 days. They were then submitted to motor evaluation and euthanized to collect the motor cortex. Measurement of mercury deposited in the brain parenchyma, evaluation of oxidative balance, quantification of cellular cytotoxicity and apoptosis and density of mature neurons and astrocytes of the motor cortex were performed. It was observed that chronic exposure to inorganic mercury caused a decrease in balance and fine motor coordination, formation of mercury deposits and oxidative stress verified by the increase of lipoperoxidation and nitrite concentration and a decrease of the total antioxidant capacity. In addition, we found that this model of exposure to inorganic mercury caused cell death by cytotoxicity and induction of apoptosis with a decreased number of neurons and astrocytes in the motor cortex. Our results provide evidence that exposure to inorganic mercury in low doses, even in spite of its poor ability to cross biological barriers, is still capable of inducing motor deficits, cell death by cytotoxicity and apoptosis, and oxidative stress in the motor cortex of adult rats.

  20. Exposure to Inorganic Mercury Causes Oxidative Stress, Cell Death, and Functional Deficits in the Motor Cortex

    Directory of Open Access Journals (Sweden)

    Francisco B. Teixeira

    2018-05-01

    Full Text Available Mercury is a toxic metal that can be found in the environment in three different forms – elemental, organic and inorganic. Inorganic mercury has a lower liposolubility, which results in a lower organism absorption and reduced passage through the blood–brain barrier. For this reason, exposure models that use inorganic mercury in rats in order to evaluate its effects on the central nervous system are rare, especially in adult subjects. This study investigated if a chronic exposure to low doses of mercury chloride (HgCl2, an inorganic form of mercury, is capable of promoting motor alterations and neurodegenerative in the motor cortex of adult rats. Forty animals were exposed to a dose of 0.375 mg/kg/day, for 45 days. They were then submitted to motor evaluation and euthanized to collect the motor cortex. Measurement of mercury deposited in the brain parenchyma, evaluation of oxidative balance, quantification of cellular cytotoxicity and apoptosis and density of mature neurons and astrocytes of the motor cortex were performed. It was observed that chronic exposure to inorganic mercury caused a decrease in balance and fine motor coordination, formation of mercury deposits and oxidative stress verified by the increase of lipoperoxidation and nitrite concentration and a decrease of the total antioxidant capacity. In addition, we found that this model of exposure to inorganic mercury caused cell death by cytotoxicity and induction of apoptosis with a decreased number of neurons and astrocytes in the motor cortex. Our results provide evidence that exposure to inorganic mercury in low doses, even in spite of its poor ability to cross biological barriers, is still capable of inducing motor deficits, cell death by cytotoxicity and apoptosis, and oxidative stress in the motor cortex of adult rats.

  1. Gene Responses in the Central Nervous System of Zebrafish Embryos Exposed to the Neurotoxicant Methyl Mercury

    NARCIS (Netherlands)

    Ho, Nga Yu; Yang, Lixin; Legradi, J.B.; Armant, Olivier; Takamiya, Masanari; Rastegar, Sepand; Strähle, Uwe

    2013-01-01

    Methyl mercury (MeHg) is a neurotoxicant with adverse effects on the development of the nervous system from fish to man. Despite a detailed understanding of the molecular mechanisms by which MeHg affects cellular homeostasis, it is still not clear how MeHg causes developmental neurotoxicity. We

  2. Mercury exposure in a large subantarctic avian community

    International Nuclear Information System (INIS)

    Carravieri, Alice; Cherel, Yves; Blévin, Pierre; Brault-Favrou, Maud; Chastel, Olivier; Bustamante, Paco

    2014-01-01

    Mercury (Hg) contamination poses potential threats to ecosystems worldwide. In order to study Hg bioavailability in the poorly documented southern Indian Ocean, Hg exposure was investigated in the large avian community of Kerguelen Islands. Adults of 27 species (480 individuals) showed a wide range of feather Hg concentrations, from 0.4 ± 0.1 to 16.6 ± 3.8 μg g −1 dry weight in Wilson's storm petrels and wandering albatrosses, respectively. Hg concentrations increased roughly in the order crustacean- < fish- ≤ squid- ≤ carrion-consumers, confirming that diet, rather than taxonomy, is an important driver of avian Hg exposure. Adults presented higher Hg concentrations than chicks, due to a longer duration of exposure, with the only exception being the subantarctic skua, likely because of feeding habits' differences of the two age-classes in this species. High Hg concentrations were reported for three species of the poorly known gadfly petrels, which merit further investigation. - Highlights: • Feather Hg concentrations were measured in 27 sympatric subantarctic bird species. • Inter-specific variation in Hg exposure depends on feeding habits, not taxonomy. • Hg concentrations were higher in adults than chicks due to longer exposure duration. • Hg is highly bioavailable in the Southern Ocean, which merits further investigation. - Mercury concentrations in feathers of sympatric subantarctic birds (27 species) are driven mainly by feeding habits and exposure duration

  3. Mercury content in Chilean fish and estimated intake levels.

    Science.gov (United States)

    Cortes, Sandra; Fortt, Antonia

    2007-09-01

    The intake of fish products is a major public health concern due to possible methyl mercury exposure, which is especially toxic to the human nervous system. This pilot study (n = 46) was designed to determine mercury concentrations in fish products for national consumption (Chilean jack mackerel, hake, Chilean mussel, tuna) and for export (salmon, Patagonian toothfish, swordfish, southern hake), and to estimate the exposure of the general population. The fish products were collected from markets in Talcahuano, Puerto Montt and Santiago. Samples were analyzed at the National Environmental Center by cold vapor atomic absorption spectrophotometry. Mercury levels in swordfish and one canned tuna sample exceeded levels prescribed by national and international standards. The remaining two export products (Patagonian toothfish, also known as Chilean sea bass, and salmon) complied with international limits, which are more demanding than Chilean regulations. Theoretical estimates of mercury intake varied from 0.08 to 3.8 microg kg(-1) bw day(-1) for high fish consumers, exceeding the provisional tolerable intake for tuna, Chilean seabass, Chilean jack mackerel and swordfish. This group appears to be at the greatest risk from mercury contamination among the Chilean population.

  4. Relations between mercury, methyl-mercury and selenium in tissues of Octopus vulgaris from the Portuguese Coast

    Energy Technology Data Exchange (ETDEWEB)

    Raimundo, Joana, E-mail: jraimundo@ipimar.p [IPIMAR - National Institute of Biological Resources, Av. Brasilia, 1449-006 Lisbon (Portugal); REQUIMTE - CQFB, Department of Chemistry, Faculty of Sciences and Technology, New University of Lisbon, Qta Torre, 2829-516 Monte da Caparica (Portugal); Vale, Carlos; Canario, Joao; Branco, Vasco [IPIMAR - National Institute of Biological Resources, Av. Brasilia, 1449-006 Lisbon (Portugal); Moura, Isabel [REQUIMTE - CQFB, Department of Chemistry, Faculty of Sciences and Technology, New University of Lisbon, Qta Torre, 2829-516 Monte da Caparica (Portugal)

    2010-06-15

    Mercury, methyl-mercury (MeHg) and selenium were determined in digestive gland and mantle of Octopus vulgaris, from three areas of the Portuguese coast. To our knowledge these are the first data on MeHg in cephalopods. Concentrations were higher in the digestive gland and percentage of MeHg in mantle. Enhanced Hg and MeHg levels were obtained in digestive gland of specimens from Olhao (3.1-7.4 and 2.0-5.0 mug g{sup -1}, respectively). Differences between areas may be partially related to Hg availability. Relationships between concentrations in mantle and digestive gland pointed to proportional increases of Hg and MeHg in tissues of specimens from Matosinhos and Cascais, but relatively constant values in mantle of individuals from Olhao (higher contamination). Se:Hg molar ratio in digestive gland was 32 and 30 in octopus from Matosinhos and Cascais, respectively, and 5.4 from Olhao. The proximity to the unit suggests demethylation as response to elevated MeHg levels in digestive gland. - Digestive gland presented high accumulation of Hg and MeHg and demethylation processes may occur with the involvement of Se

  5. Relations between mercury, methyl-mercury and selenium in tissues of Octopus vulgaris from the Portuguese Coast

    International Nuclear Information System (INIS)

    Raimundo, Joana; Vale, Carlos; Canario, Joao; Branco, Vasco; Moura, Isabel

    2010-01-01

    Mercury, methyl-mercury (MeHg) and selenium were determined in digestive gland and mantle of Octopus vulgaris, from three areas of the Portuguese coast. To our knowledge these are the first data on MeHg in cephalopods. Concentrations were higher in the digestive gland and percentage of MeHg in mantle. Enhanced Hg and MeHg levels were obtained in digestive gland of specimens from Olhao (3.1-7.4 and 2.0-5.0 μg g -1 , respectively). Differences between areas may be partially related to Hg availability. Relationships between concentrations in mantle and digestive gland pointed to proportional increases of Hg and MeHg in tissues of specimens from Matosinhos and Cascais, but relatively constant values in mantle of individuals from Olhao (higher contamination). Se:Hg molar ratio in digestive gland was 32 and 30 in octopus from Matosinhos and Cascais, respectively, and 5.4 from Olhao. The proximity to the unit suggests demethylation as response to elevated MeHg levels in digestive gland. - Digestive gland presented high accumulation of Hg and MeHg and demethylation processes may occur with the involvement of Se

  6. A new vapor generation system for mercury species based on the UV irradiation of mercaptoethanol used in the determination of total and methyl mercury in environmental and biological samples by atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yanmin; Qiu, Jianhua; Yang, Limin [College of Chemistry and Chemical Engineering, Xiamen University, Department of Chemistry and the MOE Key Laboratory of Analytical Sciences, Xiamen (China); Wang, Qiuquan [College of Chemistry and Chemical Engineering, Xiamen University, Department of Chemistry and the MOE Key Laboratory of Analytical Sciences, Xiamen (China); Xiamen University, State Key Laboratory of Marine Environmental Science, Xiamen (China)

    2007-06-15

    A new vapor generation system for mercury (Hg) species based on the irradiation of mercaptoethanol (ME) with UV was developed to provide an effective sample introduction unit for atomic fluorescence spectrometry (AFS). Preliminary investigations of the mechanism of this novel vapor generation system were based on GC-MS and FT-IR studies. Under optimum conditions, the limits of determination for inorganic divalence mercury and methyl mercury were 60 and 50 pg mL{sup -1}, respectively. Certified reference materials (BCR 463 tuna fish and BCR 580 estuarine sediment) were used to validate this new method, and the results agreed well with certified values. This new system provides an attractive alternative method of chemical vapor generation (CVG) of mercury species compared to other developed CVG systems (for example, the traditional KBH{sub 4}/NaOH-acid system). To our knowledge, this is the first systematic report on UV/ME-based Hg species vapor generation and the determination of total and methyl Hg in environmental and biological samples using UV/ME-AFS. (orig.)

  7. Inter-individual variations of human mercury exposure biomarkers: a cross-sectional assessment

    Directory of Open Access Journals (Sweden)

    Einarsson Östen

    2005-10-01

    Full Text Available Abstract Background Biomarkers for mercury (Hg exposure have frequently been used to assess exposure and risk in various groups of the general population. We have evaluated the most frequently used biomarkers and the physiology on which they are based, to explore the inter-individual variations and their suitability for exposure assessment. Methods Concentrations of total Hg (THg, inorganic Hg (IHg and organic Hg (OHg, assumed to be methylmercury; MeHg were determined in whole blood, red blood cells, plasma, hair and urine from Swedish men and women. An automated multiple injection cold vapour atomic fluorescence spectrophotometry analytical system for Hg analysis was developed, which provided high sensitivity, accuracy, and precision. The distribution of the various mercury forms in the different biological media was explored. Results About 90% of the mercury found in the red blood cells was in the form of MeHg with small inter-individual variations, and part of the IHg found in the red blood cells could be attributed to demethylated MeHg. THg in plasma was associated with both IHg and MeHg, with large inter-individual variations in the distribution between red blood cells and plasma. THg in hair reflects MeHg exposure at all exposure levels, and not IHg exposure. The small fraction of IHg in hair is most probably emanating from demethylated MeHg. The inter-individual variation in the blood to hair ratio was very large. The variability seemed to decrease with increasing OHg in blood, most probably due to more frequent fish consumption and thereby blood concentrations approaching steady state. THg in urine reflected IHg exposure, also at very low IHg exposure levels. Conclusion The use of THg concentration in whole blood as a proxy for MeHg exposure will give rise to an overestimation of the MeHg exposure depending on the degree of IHg exposure, why speciation of mercury forms is needed. THg in RBC and hair are suitable proxies for MeHg exposure

  8. Maternal exposure to arsenic, cadmium, lead, and mercury and neural tube defects in offspring

    International Nuclear Information System (INIS)

    Brender, Jean D.; Suarez, Lucina; Felkner, Marilyn; Gilani, Zunera; Stinchcomb, David; Moody, Karen; Henry, Judy; Hendricks, Katherine

    2006-01-01

    Arsenic, cadmium, lead, and mercury are neurotoxins, and some studies suggest that these elements might also be teratogens. Using a case-control study design, we investigated the relation between exposure to these heavy metals and neural tube defects (NTDs) in offspring of Mexican-American women living in 1 of the 14 Texas counties bordering Mexico. A total of 184 case-women with NTD-affected pregnancies and 225 control-women with normal live births were interviewed about their environmental and occupational exposures during the periconceptional period. Biologic samples for blood lead and urinary arsenic, cadmium, and mercury were also obtained for a subset of these women. Overall, the median levels of these biomarkers for heavy metal exposure did not differ significantly (P>0.05) between case- and control-women. However, among women in the highest income group, case-women were nine times more likely (95% confidence interval (CI) 1.4-57) than control-women to have a urinary mercury >=5.62μg/L. Case-women were 4.2 times more likely (95% CI 1.1-16) to report burning treated wood during the periconceptional period than control-women. Elevated odds ratios (ORs) were observed for maternal and paternal occupational exposures to arsenic and mercury, but the 95% CIs were consistent with unity. The 95% CIs of the ORs were also consistent with unity for higher levels of arsenic, cadmium, lead, and mercury in drinking water and among women who lived within 2 miles at the time of conception to industrial facilities with reported emissions of any of these heavy metals. Our findings suggest that maternal exposures to arsenic, cadmium, or lead are probably not significant risk factors for NTDs in offspring. However, the elevated urinary mercury levels found in this population and exposures to the combustion of treated wood may warrant further investigation

  9. Mercury in Nelson's Sparrow Subspecies at Breeding Sites

    Science.gov (United States)

    Winder, Virginia L.; Emslie, Steven D.

    2012-01-01

    Background Mercury is a persistent, biomagnifying contaminant that can cause negative effects on ecosystems. Marshes are often areas of relatively high mercury methylation and bioaccumulation. Nelson's Sparrows (Ammodramus nelsoni) use marsh habitats year-round and have been documented to exhibit tissue mercury concentrations that exceed negative effects thresholds. We sought to further characterize the potential risk of Nelson's Sparrows to mercury exposure by sampling individuals from sites within the range of each of its subspecies. Methodology/Principal Findings From 2009 to 2011, we captured adult Nelson's Sparrows at sites within the breeding range of each subspecies (A. n. nelsoni: Grand Forks and Upham, North Dakota; A. n. alterus: Moosonee, Ontario; and A. n. subvirgatus: Grand Manan Island, New Brunswick) and sampled breast feathers, the first primary feather (P1), and blood for total mercury analysis. Mean blood mercury in nelsoni individuals captured near Grand Forks ranged from 0.84±0.37 to 1.65±1.02 SD ppm among years, between 2.0 and 4.9 times as high as concentrations at the other sites (Pmercury did not vary among sites within a given sampling year (site means ranged from 0.98±0.69 to 2.71±2.93 ppm). Mean P1 mercury in alterus (2.96±1.84 ppm fw) was significantly lower than in any other sampled population (5.25±2.24–6.77±3.51 ppm; P≤0.03). Conclusions/Significance Our study further characterized mercury in Nelson's Sparrows near Grand Forks; we documented localized and potentially harmful mercury concentrations, indicating that this area may represent a biological mercury hotspot. This finding warrants further research to determine if wildlife populations of conservation or recreational interest in this area may be experiencing negative effects due to mercury exposure. We present preliminary conclusions about the risk of each sampled population to mercury exposure. PMID:22384194

  10. Modeling Mercury in Proteins

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-01

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

  11. The effect of N-acetylated DL-penicillamin and DL-homocysteine thiolactone on the mercury distribution in adult rats, rat foetuses and macaca monkeys after exposure to methyl mercuric chloride

    International Nuclear Information System (INIS)

    Aaseth, J.; Wannag, A.; Norseth, T.; Institute of Occupational Health, Oslo, Norway)

    1976-01-01

    The distribution and excretion of mercury was studied in pregnant rats, given a single intravenous dose of 2 μmol/kg of CH 3 203 HgCl on the 13th day of pregnancy. Oral treatment for one week with N-acetyl-DL-penicillamine (4 mmol/kg per day) increased the mercury excretion in faces (from 45 to 120 nmol) and urine (from 9 to 160 nmol). Such treatment mobilized mercury from all the organs tested and the foetal and maternal brain levels of mercury were decreased to 1/5 and 1/3 of the controls, respectively. A four-day period of treatment with N-acetyl-DL-penicillamine started three days after the injection of methyl mercury reduced the foetal and maternal brain levels to 1/2 and 2/3 of the controls, respectively. The rapid removal of metal deposits following treatment with N-acetyl-DL-penicillamine is attributed to a free penetration of the complexing thiol into the tissue cells in question. No signs of toxicity were detected in monkeys given an effective daily dose of the agent (4 mmol/kg) for 6 days. In contrast N-acetyl-DL-homocysteine thiolactone was found to be toxic in the monkeys. In addition, the latter agent was ineffective in increasing the mercury elimination from the brains of monkeys, rats and rat foetuses. (author)

  12. Selenium-mercury relationships in Idaho lake fish versus Northeastern USA lake fish

    Science.gov (United States)

    Methyl-mercury (MeHg) exposure to wildlife and humans occurs primarily through the foodweb, notably fish consumption. Selenium moderates the toxicity of MeHg in all animal models that utilize selenoenzymatic protein synthesis, as do humans. A Se:Hg molar ratio of <1:1 appears to...

  13. Fate and Transport of Mercury in Environmental Media and Human Exposure

    Science.gov (United States)

    Kim, Moon-Kyung

    2012-01-01

    Mercury is emitted to the atmosphere from various natural and anthropogenic sources, and degrades with difficulty in the environment. Mercury exists as various species, mainly elemental (Hg0) and divalent (Hg2+) mercury depending on its oxidation states in air and water. Mercury emitted to the atmosphere can be deposited into aqueous environments by wet and dry depositions, and some can be re-emitted into the atmosphere. The deposited mercury species, mainly Hg2+, can react with various organic compounds in water and sediment by biotic reactions mediated by sulfur-reducing bacteria, and abiotic reactions mediated by sunlight photolysis, resulting in conversion into organic mercury such as methylmercury (MeHg). MeHg can be bioaccumulated through the food web in the ecosystem, finally exposing humans who consume fish. For a better understanding of how humans are exposed to mercury in the environment, this review paper summarizes the mechanisms of emission, fate and transport, speciation chemistry, bioaccumulation, levels of contamination in environmental media, and finally exposure assessment of humans. PMID:23230463

  14. Mercury exposure, malaria, and serum antinuclear/antinucleolar antibodies in amazon populations in Brazil: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Burek CL

    2004-11-01

    Full Text Available Abstract Background Mercury is an immunotoxic metal that induces autoimmune disease in rodents. Highly susceptible mouse strains such as SJL/N, A.SW, B10.S (H-2s develop multiple autoimmune manifestations after exposure to inorganic mercury, including lymphoproliferation, elevated levels of autoantibodies, overproduction of IgG and IgE, and circulating immune complexes in kidney and vasculature. A few studies have examined relationships between mercury exposures and adverse immunological reactions in humans, but there is little evidence of mercury-associated autoimmunity in humans. Methods To test the immunotoxic effects of mercury in humans, we studied communities in Amazonian Brazil with well-characterized exposures to mercury. Information was collected on diet, mercury exposures, demographic data, and medical history. Antinuclear and antinucleolar autoantibodies (ANA and ANoA were measured by indirect immunofluorescence. Anti-fibrillarin autoantibodies (AFA were measured by immunoblotting. Results In a gold mining site, there was a high prevalence of ANA and ANoA: 40.8% with detectable ANoA at ≥1:10 serum dilution, and 54.1% with detectable ANA (of which 15% had also detectable ANoA. In a riverine town, where the population is exposed to methylmercury by fish consumption, both prevalence and levels of autoantibodies were lower: 18% with detectable ANoA and 10.7% with detectable ANA. In a reference site with lower mercury exposures, both prevalence and levels of autoantibodies were much lower: only 2.0% detectable ANoA, and only 7.1% with detectable ANA. In the gold mining population, we also examined serum for AFA in those subjects with detectable ANoA (≥1:10. There was no evidence for mercury induction of this autoantibody. Conclusions This is the first study to report immunologic changes, indicative of autoimmune dysfunction in persons exposed to mercury, which may also reflect interactions with infectious disease and other factors.

  15. Mercury Exposure in a Riverside Amazon Population, Brazil: A Study of the Ototoxicity of Methylmercury

    Directory of Open Access Journals (Sweden)

    Hoshino, Ana

    2015-02-01

    Full Text Available Introduction Mercury poisoning causes hearing loss in humans and animals. Acute and long-term exposures produce irreversible peripheral and central auditory system damage, and mercury in its various forms of presentation in the environment is ototoxic. Objective We investigated the otoacoustic emissions responses in a riverside population exposed to environmental mercury by analyzing the inhibitory effect of the medial olivocochlear system (MOCS on transient otoacoustic emissions (TEOAE. Methods The purpose of the research was to evaluate the entire community independently of variables of sex and age. All of the participants were born and lived in a riverside community. After otolaryngologic evaluation, participants were received tympanometry, evaluation of contralateral acoustic reflexes, pure tone audiometry, and recording of TEOAEs with nonlinear click stimulation. Hair samples were collect to measure mercury levels. Results There was no significant correlation between the inhibitory effect of the MOCS, age, and the level of mercury in the hair. Conclusions The pathophysiological effects of chronic exposure may be subtle and nonspecific and can have a long period of latency; therefore, it will be important to monitor the effects of mercury exposure in the central auditory system of the Amazon population over time. Longitudinal studies should be performed to determine whether the inhibitory effect of the MOCS on otoacoustic emissions can be an evaluation method and diagnostic tool in populations exposed to mercury.

  16. Importance of Dissolved Neutral Hg-Sulfides, Energy Rich Organic Matter and total Hg Concentrations for Methyl Mercury Production in Sediments

    Science.gov (United States)

    Drott, A.; Skyllberg, U.

    2007-12-01

    Methyl mercury (MeHg) is the mercury form that biomagnifies to the greatest extent in aquatic food webs. Therefore information about factors determining MeHg concentrations is critical for accurate risk assessment of contaminated environments. The concentration of MeHg in wetlands and sediments is the net result of: 1) methylation rates, 2) demethylation rates, and 3) input/output processes. In this study, the main controls on Hg methylation rates and total concentrations of MeHg, were investigated at eight sites in Sweden with sediments that had been subjected to local Hg contamination either as Hg(0), or as phenyl-Hg. Sediments were selected to represent a gradient in total Hg concentration, temperature climate, salinity, primary productivity, and organic C content and quality. Most sediments were high in organic matter content due to wood fibre efflux from pulp and paper industry. The pore water was analysed for total Hg, MeHg, DOC, H2S(aq), pH, DOC, Cl and Br. The chemical speciation of Hg(II) and MeHg in pore water was calculated using equilibrium models. Potential methylation and demethylation rates in sediments were determined in incubation experiments at 23° C under N2(g) for 48 h, after addition of isotopically enriched 201Hg(II) and Me204Hg. In all surface (0-20 cm) sediments there was a significant (pdetermined specific potential methylation rate constant (Km, day-1) and % MeHg (concentrations of MeHg normalized to total Hg) in the sediment. This indicates that MeHg production overruled degradation and input/output processes of MeHg in surface sediments, and that % MeHg in surface sediments may be used as a proxy for net production of MeHg. To our knowledge, these are the first data showing significant positive relationships between short term (48 h) MeHg production and longer term accumulation of MeHg, across a range of sites with different properties (1). If MeHg was not normalized to total Hg, the relationship was not significant. For sub-sets of

  17. Form of Dietary Methylmercury does not Affect Total Mercury Accumulation in the Tissues of Zebra Finch.

    Science.gov (United States)

    Varian-Ramos, Claire W; Whitney, Margaret; Rice, Gary W; Cristol, Daniel A

    2017-07-01

    Exposure to mercury in humans, other mammals, and birds is primarily dietary, with mercury in the methylated form and bound to cysteine in the tissues of prey items. Yet dosing studies are generally carried out using methylmercury chloride. Here we tested whether the accumulation of total mercury in zebra finch blood, egg, muscle, liver, kidney or brain differed depending on whether dietary mercury was complexed with chloride or cysteine. We found no effect of form of mercury on tissue accumulation. Some previous studies have found lower accumulation of mercury in tissues of animals fed complexed mercury. Much remains to be understood about what happens to ingested mercury once it enters the intestines, but our results suggest that dietary studies using methylmercury chloride in birds will produce similar tissue accumulation levels to those using methylmercury cysteine.

  18. Mercury hair levels and factors that influence exposure for residents of Huancavelica, Peru

    Science.gov (United States)

    Between 1564 and 1810, nearly 17,000 metric tons of mercury (Hg) vapor were released to the environment during cinnabar refining in the small town of Huancavelica, Peru. The present study characterizes individual exposure to mercury using total and speciated Hg from residential s...

  19. Cadmium and mercury exposure over time in Swedish children

    Energy Technology Data Exchange (ETDEWEB)

    Lundh, T., E-mail: Thomas.Lundh@med.lu.se [Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE−22185 Lund (Sweden); Axmon, A., E-mail: Anna.Axmon@med.lu.se [Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE−22185 Lund (Sweden); Skerfving, S., E-mail: Staffan.Skerfving@med.lu.se [Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE−22185 Lund (Sweden); Broberg, K., E-mail: Karin.Broberg@ki.se [Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE−22185 Lund (Sweden); Unit of Metals and Health, Institute of Environmental Medicine, Karolinska Institutet, Nobels väg 13, SE-171 77 Stockholm (Sweden)

    2016-10-15

    Purpose: Knowledge about changes in exposure to toxic metals over time remains very sparse, in particular for children, the most vulnerable group. Here, we assessed whether a reduction in environmental pollution with cadmium (Cd) and mercury (Hg) caused a change in exposure over time. In total, 1257 children (age 4–9) in two towns in Sweden were sampled once in 1986–2013. Blood concentrations of Cd (b-Cd; n=1120) and Hg (b-Hg; n=560) were determined. Results: The median b-Cd was 0.10 (geometric mean 0.10; range 0.010–0.61) μg/L and b-Hg was 0.91 (geometric mean 0.83; range 0.021–8.2) μg/L. Children living close to a smelter had higher b-Cd and b-Hg than those in urban and rural areas. There was no sex difference in b-Cd or b-Hg, and b-Cd and b-Hg showed no significant accumulation by age. b-Cd decreased only slightly (0.7% per year, p<0.001) over the study period. In contrast, b-Hg did show a clear decrease over the study period (3% per year, p<0.001). Conclusions: The exposure to Cd was very low but still might increase the risk of disease later in life. Moreover, b-Cd only showed a minor decrease, indicating that Cd pollution should be further restricted. b-Hg was relatively low and decreasing, probably because of reduced use of dental amalgam and lower Hg intake from fish. The b-Cd and b-Hg levels decreased much less than the levels of lead in the blood as previously found in the same children. - Highlights: • There are few studies of time trends for exposure to toxic metals, except for lead. • 1986–2013 we studied blood levels of cadmium and mercury in 1257 Swedish children. • The median blood concentration of cadmium was 0.10 μg/L, of mercury 0.83 μg/L. • Cadmium perhaps decreased by 0.7% per year, mercury by 3% per year. • Cadmium accumulation may result in toxic levels in elderly women.

  20. Mercury exposure as a function of fish consumption in two Asian communities in coastal Virginia, USA.

    Science.gov (United States)

    Xu, Xiaoyu; Newman, Michael C

    2015-04-01

    Fish consumption and associated mercury exposure were explored for two Asian-dominated church communities in coastal Virginia and compared with that of two non-Asian church communities. Seafood-consumption rates for the Chinese (36.9 g/person/day) and Vietnamese (52.7 g/person/day) church communities were greater than the general United States fish-consumption rate (12.8 g/person/day). Correspondingly, hair mercury concentrations for people from the Chinese (0.52 µg/g) and the Vietnamese church (1.46 µg/g) were greater than the overall level for United States women (0.20 µg/g) but lower than the published World Health Organization exposure threshold (14 µg/g). A conventional regression model indicated a positive relationship between seafood consumption rates and hair mercury concentrations suggesting the importance of mercury exposure through seafood consumption. The annual-average daily methylmercury intake rate for the studied communities calculated by Monte Carlo simulations followed the sequence: Vietnamese community > Chinese community > non-Asian communities. Regardless, their daily methylmercury intake rates were all lower than the United States Environmental Protection Agency reference dose of 0.1 µg/kg body weight-day. In conclusion, fish-consumption patterns differed among communities, which resulted in different levels of mercury exposure. The greater seafood and mercury ingestion rates of studied Asian groups compared with non-Asian groups suggest the need for specific seafood consumption advice for ethnic communities in the United States. Otherwise the health benefits from fish consumption could be perceived as trivial compared with the ill-defined risk of mercury exposure.

  1. Brain, kidney and liver sup 203 Hg-methyl mercury uptake in the rat: Relationship to the neutral amino acid carrier

    Energy Technology Data Exchange (ETDEWEB)

    Aschner, M [Department of Pharmacology and Toxicology, and the Interdepartmental Neuroscience Training Program, Albany Medical College, Albany, NY (USA)

    1989-01-01

    To investigate the effect of L-neutral amino acids on tissue levels of methyl mercury in the adult animal, rats were infused into the external jugular vein with solutions containing (a) 0.05 mM {sup 203}Hg-MeHgCl and saline, (b) 0.05 mM {sup 203}Hg-MgHgCl-0.1 mM L-cysteine, (c) 0.05 mM {sup 203}Hg-MeHgCl-0.1 mM L-cysteine-0.1 mM L-methionine, (d) 0.05 mM {sup 203}Hg-MeHgCl-0.1 mM L-leucine, or (e) 0.05 mM {sup 203}Hg-MeHgCl-0.1 mM L-cysteine-0.1 mM L-leucine. Groups of animals were sacrificed at 3 min. 7 hr, and 96 hr. Brain, kidney, and liver {sup 203}Hg radioactivity was measured by means of gamma-scintillation spectrometry. Brain {sup 203}Hg concentrations L-cysteine treated animals were significantly higher compared with saline treated animals (P<0.05) at 3 min., 7 hr and 96 hr. The coinjection or coinfusion of methyl mercury with L-cysteine and L-methionine abolished the L-cysteine-mediated brain {sup 203}Hg uptake (P<0.05), at each sacrifice time. Kidney and liver {sup 203}Hg concentrations were not significantly different in any of the treatment groups compared with controls, irrespective of the sacrifice time. Furthermore, the percentage of diffusible {sup 203}Hg (non-protein bound) at each sacrifice time was not statistically different irrespective of the treatment assigned. These results suggest that methyl mercury L-cysteine conjugates in the plasma may share a common transport step with the L-neutral amino acid carrier transport system and indicate the presence in brain capillaries of a transport system capable of selectively mediating methyl mercury uptake across the capillary endothelial cell membrane. (author).

  2. Exposure of great egret (Ardea albus) nestlings to mercury through diet in the Everglades ecosystem

    Science.gov (United States)

    Frederick, Peter C; Spalding, Marilyn G.; Sepalveda, Maria S.; Williams, Gary E.; Nico, Leo G.; Robins, Robert H.

    1999-01-01

    We estimated exposure of great egret (Ardea albus) nestlings to mercury in food in the Florida Everglades, USA, by collecting regurgitated food samples during the 1993 to 1996 breeding seasons and during 1995 measured concentrations of mercury in individual prey items from those samples. Great egret nestlings had a diet composed predominantly of fish (>95% of biomass), though the species composition of fish in the diet fluctuated considerably among years. Great egrets concentrated on the larger fish available in the marsh, especially members of the Centrarchidae. The importance of all nonnative fish fluctuated from 0 to 32% of the diet by biomass and was dominated by pike killifish (Belonesox belizanus) and cichlids (Cichlidae). Total mercury concentrations in prey fish ranged from 0.04 to 1.40 mg/kg wet weight, and we found a significant relationship between mass of individual fish and mercury concentration. We estimated the concentration of total mercury in the diet as a whole by weighting the mercury concentration in a given fish species by the proportion of that species in the diet. We estimate that total mercury concentrations in the diets ranged among years from 0.37 to 0.47 mg/kg fish (4-year mean = 0.41 mg/kg). We estimated total mercury exposure in great egret nestlings by combining these mercury concentrations with measurements of food intake rate, as measured over the course of the nestling period in both lab and field situations. We estimate that, at the 0.41 mg/kg level, nestlings would ingest 4.32 mg total mercury during an 80-day nestling period. Captive feeding studies reported elsewhere suggest that this level of exposure in the wild could be associated with reduced fledging mass, increased lethargy, decreased appetite, and, possibly, poor health and juvenile survival.

  3. Exposures of dental professionals to elemental mercury and methylmercury.

    Science.gov (United States)

    Goodrich, Jaclyn M; Chou, Hwai-Nan; Gruninger, Stephen E; Franzblau, Alfred; Basu, Niladri

    2016-01-01

    Mercury (Hg) exposure, a worldwide public health concern, predominantly takes two forms--methylmercury from fish consumption and elemental Hg from dental amalgam restorations. We recruited 630 dental professionals from an American Dental Association meeting to assess Hg body burden and primary sources of exposure in a dually exposed population. Participants described occupational practices and fish consumption patterns via questionnaire. Hg levels in biomarkers of elemental Hg (urine) and methylmercury (hair and blood) were measured with a Direct Mercury Analyzer-80 and were higher than the general US population. Geometric means (95% CI) were 1.28 (1.19-1.37) μg/l in urine, 0.60 (0.54-0.67) μg/g in hair and 3.67 (3.38-3.98) μg/l in blood. In multivariable linear regression, personal amalgams predicted urine Hg levels along with total years in dentistry, amalgams handled, working hours and sex. Fish consumption patterns predicted hair and blood Hg levels, which were higher among Asians compared with Caucasians. Five species contributed the majority of the estimated Hg intake from fish--swordfish, fresh tuna, white canned tuna, whitefish and king mackerel. When studying populations with occupational exposure to Hg, it is important to assess environmental exposures to both elemental Hg and methylmercury as these constitute a large proportion of total exposure.

  4. Exposure of rainbow trout milt to mercury and cadmium alters sperm motility parameters and reproductive success

    International Nuclear Information System (INIS)

    Dietrich, Grzegorz J.; Dietrich, Mariola; Kowalski, R.K.; Dobosz, Stefan; Karol, Halina; Demianowicz, Wieslaw; Glogowski, Jan

    2010-01-01

    In the current work, seminal plasma was used for the first time as an incubation medium for monitoring short-time exposure effects of sublethal concentrations of mercury and cadmium ions on rainbow trout sperm. Sperm motility parameters (CASA) and hatching rates were used as gamete quality markers. Additionally live/dead sperm viability test and comet assay of DNA fragmentation were performed. We demonstrated that computer-assisted sperm motility analysis (CASA) may serve as a predictor of reproductive success, when milt contaminated with heavy metals is used. Results presented in this study demonstrate that mercury ions altered sperm motility characteristics at 1-10 mg Hg 2+ /l and 10 mg Cd 2+ /l and hatching rates at 10 mg Hg 2+ /l and 10 mg Cd 2+ /l after 4 h of exposure. Although mercury ions affected sperm motility parameters immediately after dilution with milt as well as at 4 h of exposure, no differences in sperm motility parameters were found between intact and mercury-treated milt after 24 h of exposure. Our results suggest that rainbow trout seminal plasma has a protective role against the toxic effects of mercury ions of rainbow trout sperm motility.

  5. Exposure to dietary mercury alters cognition and behavior of zebra finches.

    Science.gov (United States)

    Swaddle, John P; Diehl, Tessa R; Taylor, Capwell E; Fanaee, Aaron S; Benson, Jessica L; Huckstep, Neil R; Cristol, Daniel A

    2017-04-01

    Environmental stressors can negatively affect avian cognitive abilities, potentially reducing fitness, for example by altering response to predators, display to mates, or memory of locations of food. We expand on current knowledge by investigating the effects of dietary mercury, a ubiquitous environmental pollutant and known neurotoxin, on avian cognition. Zebra finches Taeniopygia guttata were dosed for their entire lives with sub-lethal levels of mercury, at the environmentally relevant dose of 1.2 parts per million. In our first study, we compared the dosed birds with controls of the same age using tests of three cognitive abilities: spatial memory, inhibitory control, and color association. In the spatial memory assay, birds were tested on their ability to learn and remember the location of hidden food in their cage. The inhibitory control assay measured their ability to ignore visible but inaccessible food in favor of a learned behavior that provided the same reward. Finally, the color association task tested each bird's ability to associate a specific color with the presence of hidden food. Dietary mercury negatively affected spatial memory ability but not inhibitory control or color association. Our second study focused on three behavioral assays not tied to a specific skill or problem-solving: activity level, neophobia, and social dominance. Zebra finches exposed to dietary mercury throughout their lives were subordinate to, and more active than, control birds. We found no evidence that mercury exposure influenced our metric of neophobia. Together, these results suggest that sub-lethal exposure to environmental mercury selectively harms neurological pathways that control different cognitive abilities, with complex effects on behavior and fitness.

  6. Seasonal mercury exposure and oxidant-antioxidant status of James Bay sport fishermen.

    Science.gov (United States)

    Bélanger, Marie-Claire; Mirault, Marc-Edouard; Dewailly, Eric; Plante, Michel; Berthiaume, Line; Noël, Micheline; Julien, Pierre

    2008-05-01

    The effects of a moderate seasonal exposure to methylmercury on plasma low-density lipoprotein (LDL) oxidation and cardiovascular risk indices are not known. The objective of the study was to assess the effects of a seasonal exposure to mercury at similar dose reported to increase cardiovascular risk through fish consumption. Effects on lipoprotein cholesterol and fatty acid profiles, LDL oxidation, and blood oxidant-antioxidant balance were to be assessed in sport fishermen presenting normal blood selenium and omega-3 fatty acid contents. Thirty-one healthy James Bay sport fishermen were assessed for within-subject longitudinal seasonal variations in hair and blood mercury, plasma oxidized LDL, lipophilic antioxidants, homocysteine, blood selenium, and glutathione peroxidase and reductase activities determined before and after the fishing season and compared by matched-pair tests. Hair mercury doubled during the fishing season (2.8+/-0.4 microg/g, P<.0001). Baseline blood selenium, homocysteine, and erythrocyte fatty acid profiles did not change. Plasma high-density lipoprotein cholesterol increased (+5%, P=.05), whereas very low-density lipoprotein cholesterol and oxidized LDL decreased (-8%, P=.05; -18%, P=.008). Blood glutathione peroxidase (+9.7%, P=.001), glutathione reductase (+7.2%, P<.0001), and total glutathione (+45% P<.0001) increased during the fishing season. Plasma total coenzyme Q10 (+13%, P=.02), ubiquinone-10 (+67%, P=.03), and beta-carotene (+46%, P=.01) also increased, whereas vitamin E status was unaffected. Pairwise correlations revealed no association between mercury exposure and any of the biomarkers investigated. In contrast, strong predictors of cardiovascular risk such as high-density lipoprotein cholesterol, oxidized LDL, and glutathione peroxidase improved during the fishing season despite elevated methylmercury exposure. The beneficial effects of seasonal fishing activity and fish consumption on cardiovascular health may suppress

  7. Mercury Exposure: Protein Biomarkers of Mercury Exposure in Jaraqui Fish from the Amazon Region.

    Science.gov (United States)

    Vieira, José Cavalcante Souza; Braga, Camila Pereira; de Oliveira, Grasieli; Padilha, Cilene do Carmo Federici; de Moraes, Paula Martin; Zara, Luiz Fabricio; Leite, Aline de Lima; Buzalaf, Marília Afonso Rabelo; Padilha, Pedro de Magalhães

    2018-05-01

    This study presents data on the extraction and characterization of proteins associated with mercury in the muscle and liver tissues of jaraqui (Semaprochilodus spp.) from the Madeira River in the Brazilian Amazon. Protein fractionation was carried out by two-dimensional electrophoresis (2D-PAGE). Mercury determination in tissues, pellets, and protein spots was performed by graphite furnace atomic absorption spectrometry (GFAAS). Proteins in the spots that showed mercury were characterized by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The highest mercury concentrations were found in liver tissues and pellets (426 ± 6 and 277 ± 4 μg kg -1 ), followed by muscle tissues and pellets (132 ± 4 and 86 ± 1 μg kg -1 , respectively). Mercury quantification in the protein spots allowed us to propose stoichiometric ratios in the range of 1-4 mercury atoms per molecule of protein in the protein spots. The proteins characterized in the analysis by ESI-MS/MS were keratin, type II cytoskeletal 8, parvalbumin beta, parvalbumin-2, ubiquitin-40S ribosomal S27a, 39S ribosomal protein L36 mitochondrial, hemoglobin subunit beta, and hemoglobin subunit beta-A/B. The results suggest that proteins such as ubiquitin-40S ribosomal protein S27a, which have specific domains, possibly zinc finger, can be used as biomarkers of mercury, whereas mercury and zinc present characteristics of soft acids.

  8. Significance of fingernail and toenail mercury concentrations as biomarkers for prenatal methylmercury exposure in relation to segmental hair mercury concentrations.

    Science.gov (United States)

    Sakamoto, Mineshi; Chan, Hing M; Domingo, José L; Oliveira, Ricardo B; Kawakami, Shoichi; Murata, Katsuyuki

    2015-01-01

    To investigate the appropriateness of mercury (Hg) concentrations in fingernails and toenails at parturition for detecting prenatal exposure to methylmercury (MeHg). Total Hg concentrations were measured in 54 paired samples of fingernails, toenails, maternal blood, and maternal hair (1cm incremental segments from the scalp toward the tip) collected at 4th weeks of (early) pregnancy, and the same specimens and cord blood collected at parturition. Strong correlations were observed between Hg concentrations in fingernails and toenails at early pregnancy (r=0.923, pMercury concentrations in fingernails and toenails at parturition represented strong correlations with those in cord blood (r=0.803, pMercury in fingernails and toenails at early pregnancy reflected the maternal Hg body burden level approximately 5 months retroactively. At parturition, Hg levels in fingernails and toenails also showed strong correlations with those in cord blood. In addition, Hg levels in fingernails and toenails at parturition reflected more recent MeHg exposure, compared with those at early pregnancy. These results suggest that fingernails and toenails at parturition are useful biomarkers for prenatal MeHg exposure for mothers and fetuses, especially during the third-trimester of gestation. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Neonate exposure to thimerosal mercury from hepatitis B vaccines.

    Science.gov (United States)

    Dórea, José G; Marques, Rejane C; Brandão, Katiane G

    2009-08-01

    Infant exposure to ethylmercury (EtHg) has not only increased but is starting earlier as a result of the current immunization schedule that uses thimerosal-containing vaccines (TCVs). Although vaccination schedule varies considerably between countries, infants in less-developed countries continue to be exposed to EtHg derived from more affordable TCVs. We studied the exposure of newborns to EtHg from hepatitis B vaccines; hospital records (21,685) were summarized for the years 2001 to 2005 regarding date of birth, vaccination date, and birth weight. Most of the vaccinations occurred in the first 24 hours postdelivery; over the 5 years, there was an increase in vaccinations within hours of birth (same day), from 7.4% (2001) to 87.8% (2005). Nearly 94.6% of infants are now being vaccinated within the first 24 hours. Range of mercury exposure spread from 4.2 to 21.1 microg mercury/kg body weight for those receiving TCVs with the highest thimerosal concentration; these exposure levels are conservative for 2% of children receiving vaccines within 2 to 3 postnatal days, when they are still going through physiological postnatal weight loss. Because of the particular timing (transitioning from in utero to ex utero metabolism) and specific aspects of exposure (i.e., parenteral mode, bypassing gastroenteric barriers) and dose (related to vaccine manufacturer and with variation in birth weight), this study reveals critical issues that can modulate toxicokinetics and toxicodynamics of organomercurials in neonates.

  10. SRXRF study of trace elements in hippocampus of pup rats after prenatal and postnatal exposure to low-level mercury

    International Nuclear Information System (INIS)

    Zhang Fang; Feng Weiyue; Chai Zhifang; Wang Meng; Shi Junwen; Huang Yuying; He Wei

    2005-01-01

    Since the pollution of mercury in the environment still keeps high, more and more concerns over mercury toxicity are focused on the potential risk associated with relatively low-dose and long-term mercury exposure in the environment. It is well known that fetus and developing children are the susceptive victims of mercury damage. Therefore, high attention is focused on whether the prenatal and postnatal exposure to relatively low level of mercury will be harmful to children development. Some epidemiological studies reported that the methylmercury-related neuropsychological deficits were mainly found in the domains of cognitional parts, such as language, attention, memory, and so forth, Our previous study found out that high level of mercury was accumulated in the pup hippocampus after their prenatal and postnatal exposure to low dose of inorganic mercury. Synchrotron radiation X-ray fluorescence technique (SRXRF) is characterized of its simultaneous determination of multi-elements, high sensitivity, small sampling amount and microanalysis. SRXRF does not cause the damage of irradiated samples. Thus, it makes possible to measure the distributions of trace elements in a selected area. In this study, in order to study the effects of low-level mercury exposure to pup rat brain, some oxidation-related elements, e.g. Cu, Fe and Mn in pup hippocampus after in utero and weaning exposure to low-level inorganic mercury were determined by SRXRF. The experiment was performed at a synchrotron radiation facility at Institute of High Energy Physics. And the spot size of the beam irradiating on the sample was adjusted to about 100 x 200 μm 2 , Each spot was irradiated for about 100 s. The spectra were analyzed by the AXIL program. Additionally, the activities of some important antioxidant enzymes, such as GSH-Px, SOD, CAT, were also measured together with the content of malondialdehyde (MDA). The results showed that mercury exposure could lead to significant increase of both

  11. River transport of mercury from artisanal and small-scale gold mining and risks for dietary mercury exposure in Madre de Dios, Peru.

    Science.gov (United States)

    Diringer, Sarah E; Feingold, Beth J; Ortiz, Ernesto J; Gallis, John A; Araújo-Flores, Julio M; Berky, Axel; Pan, William K Y; Hsu-Kim, Heileen

    2015-02-01

    Artisanal and small-scale gold mining (ASGM) is a major contributor to deforestation and the largest anthropogenic source of atmospheric mercury worldwide. Despite significant information on the direct health impacts of mercury to ASGM miners, the impact of mercury contamination on downstream communities has not been well characterized, particularly in Peru's Madre de Dios region. In this area, ASGM has increased significantly since 2000 and has led to substantial political and social controversy. This research examined the spatial distribution and transport of mercury through the Madre de Dios River with distance from ASGM activity. This study also characterized risks for dietary mercury exposure to local residents who depend on fish from the river. River sediment, suspended solids from the water column, and fish samples were collected in 2013 at 62 sites near 17 communities over a 560 km stretch of the Madre de Dios River and its major tributaries. In areas downstream of known ASGM activity, mercury concentrations in sediment, suspended solids, and fish within the Madre de Dios River were elevated relative to locations upstream of mining. Fish tissue mercury concentrations were observed at levels representing a public health threat, with greater than one-third of carnivorous fish exceeding the international health standard of 0.5 mg kg(-1). This study demonstrates that communities located hundreds of kilometers downstream of ASGM activity, including children and indigenous populations who may not be involved in mining, are at risk of dietary mercury exposure that exceed acceptable body burdens. This report represents the first systematic study of the region to aid policy decision-making related to ASGM activities in Peru.

  12. Microbial Community Response to Carbon Substrate Amendment in Mercury Impacted Sediments: Implications on Microbial Methylation of Mercury.

    Science.gov (United States)

    Elias, D. A.; Somenahally, A. C.; Moberly, J. G.; Hurt, R. A., Jr.; Brown, S. D.; Podar, M.; Palumbo, A. V.; Gilmour, C. C.

    2015-12-01

    Methylmercury (MeHg) is a neurotoxic and bio-accumulative product of the microbial methylation of inorganic mercury (Hg(II)). Methylating organisms are now known to exist in almost all anaerobic niches including fermentation, Fe(III)- and sulfate- reduction as well as methanogenesis. The study objective was to determine the effect of different carbon sources on the microbial community and methylating populations in particular along a Hg contaminated creek. Sediment cores from upstream and downstream at the Hg contaminated East Fork Poplar Creek (EFPC), Oak Ridge TN, and a background site were sectioned by depth, and Hg-methylation potential (HgMP) assays were performed using stable isotope spikes. Sediments from the lowest depth possessed the highest in-situ activity. Replicate samples were amended with different carbon substrates (cellulose, acetate, propionate, lactate, ethanol and methanol), spiked with stable isotopes for HgMP assays and incubated for 24hrs. Sequencing of the 16S rRNA gene was performed to determine alterations in Bacterial and Archaeal population dynamics. Additionally, bioinformatics and our new qualitative and quantitative hgcAB primers were utilized to determine microbial community structure alterations and correlate organism and gene abundance with altered MeHg generation. HgMP was significantly reduced in cellulose amended sediments while acetate and propionate slightly decreased HgMP in both sites. Methanol, ethanol and lactate increased the HgMP in EFPC downstream while cellulose amendment significantly decreased the Proteobacteria, and the Firmicutes increased but none are currently known to produce MeHg. Geobacter bemidjiensis in particular significantly decreased in cellulose amended sediments in all three sites from being predominant in-situ. This suggests that in EFPC downstream and background sites, the prevalent Hg-methyaltors might be Deltaprotebacteria, since upstream, cellulose amendment did not reduce HgMP even though

  13. Sorption of mercury on chemically synthesized polyaniline

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  14. Multi-tissue analyses reveal limited inter-annual and seasonal variation in mercury exposure in an Antarctic penguin community.

    Science.gov (United States)

    Brasso, Rebecka L; Polito, Michael J; Emslie, Steven D

    2014-10-01

    Inter-annual variation in tissue mercury concentrations in birds can result from annual changes in the bioavailability of mercury or shifts in dietary composition and/or trophic level. We investigated potential annual variability in mercury dynamics in the Antarctic marine food web using Pygoscelis penguins as biomonitors. Eggshell membrane, chick down, and adult feathers were collected from three species of sympatrically breeding Pygoscelis penguins during the austral summers of 2006/2007-2010/2011. To evaluate the hypothesis that mercury concentrations in penguins exhibit significant inter-annual variation and to determine the potential source of such variation (dietary or environmental), we compared tissue mercury concentrations with trophic levels as indicated by δ(15)N values from all species and tissues. Overall, no inter-annual variation in mercury was observed in adult feathers suggesting that mercury exposure, on an annual scale, was consistent for Pygoscelis penguins. However, when examining tissues that reflected more discrete time periods (chick down and eggshell membrane) relative to adult feathers, we found some evidence of inter-annual variation in mercury exposure during penguins' pre-breeding and chick rearing periods. Evidence of inter-annual variation in penguin trophic level was also limited suggesting that foraging ecology and environmental factors related to the bioavailability of mercury may provide more explanatory power for mercury exposure compared to trophic level alone. Even so, the variable strength of relationships observed between trophic level and tissue mercury concentrations across and within Pygoscelis penguin species suggest that caution is required when selecting appropriate species and tissue combinations for environmental biomonitoring studies in Antarctica.

  15. Fish consumption and bioindicators of inorganic mercury exposure

    International Nuclear Information System (INIS)

    Sousa Passos, Carlos Jose; Mergler, Donna; Lemire, Melanie; Fillion, Myriam; Guimaraes, Jean Remy Davee

    2007-01-01

    Background: The direct and close relationship between fish consumption and blood and hair mercury (Hg) levels is well known, but the influence of fish consumption on inorganic mercury in blood (B-IHg) and in urine (U-Hg) is unclear. Objective: Examine the relationship between fish consumption, total, inorganic and organic blood Hg levels and urinary Hg concentration. Methods: A cross-sectional study was carried out on 171 persons from 7 riparian communities on the Tapajos River (Brazilian Amazon), with no history of inorganic Hg exposure from occupation or dental amalgams. During the rising water season in 2004, participants responded to a dietary survey, based on a seven-day recall of fish and fruit consumption frequency, and socio-demographic information was recorded. Blood and urine samples were collected. Total, organic and inorganic Hg in blood as well as U-Hg were determined by Atomic Absorption Spectrometry. Results: On average, participants consumed 7.4 fish meals/week and 8.8 fruits/week. Blood total Hg averaged 38.6 ± 21.7 μg/L, and the average percentage of B-IHg was 13.8%. Average organic Hg (MeHg) was 33.6 ± 19.4 μg/L, B-IHg was 5.0 ± 2.6 μg/L, while average U-Hg was 7.5 ± 6.9 μg/L, with 19.9% of participants presenting U-Hg levels above 10 μg/L. B-IHg was highly significantly related to the number of meals of carnivorous fish, but no relation was observed with non-carnivorous fish; it was negatively related to fruit consumption, increased with age, was higher among those who were born in the Tapajos region, and varied with community. U-Hg was also significantly related to carnivorous but not non-carnivorous fish consumption, showed a tendency towards a negative relation with fruit consumption, was higher among men compared to women and higher among those born in the region. U-Hg was strongly related to I-Hg, blood methyl Hg (B-MeHg) and blood total Hg (B-THg). The Odds Ratio (OR) for U-Hg above 10 μg/L for those who ate > 4 carnivorous fish

  16. Brain, kidney and liver 203Hg-methyl mercury uptake in the rat: Relationship to the neutral amino acid carrier

    International Nuclear Information System (INIS)

    Aschner, M.

    1989-01-01

    To investigate the effect of L-neutral amino acids on tissue levels of methyl mercury in the adult animal, rats were infused into the external jugular vein with solutions containing a) 0.05 mM 203 Hg-MeHgCl and saline, b) 0.05 mM 203 Hg-MgHgCl-0.1 mM L-cysteine, c) 0.05 mM 203 Hg-MeHgCl-0.1 mM L-cysteine-0.1 mM L-methionine, d) 0.05 mM 203 Hg-MeHgCl-0.1 mM L-leucine, or e) 0.05 mM 203 Hg-MeHgCl-0.1 mM L-cysteine-0.1 mM L-leucine. Groups of animals were sacrificed at 3 min. 7 hr, and 96 hr. Brain, kidney, and liver 203 Hg radioactivity was measured by means of gamma-scintillation spectrometry. Brain 203 Hg concentrations L-cysteine treated animals were significantly higher compared with saline treated animals (P 203 Hg uptake (P 203 Hg concentrations were not significantly different in any of the treatment groups compared with controls, irrespective of the sacrifice time. Furthermore, the percentage of diffusible 203 Hg (non-protein bound) at each sacrifice time was not statistically different irrespective of the treatment assigned. These results suggest that methyl mercury L-cysteine conjugates in the plasma may share a common transport step with the L-neutral amino acid carrier transport system and indicate the presence in brain capillaries of a transport system capable of selectively mediating methyl mercury uptake across the capillary endothelial cell membrane. (author)

  17. Mercury analysis and speciation: The potential role of the IAEA

    International Nuclear Information System (INIS)

    Horvat, Milena

    2001-01-01

    Owing to the toxicity of its methylated form, its accumulation in biota and biomagnification in the aquatic food chain, mercury has been at the centre of considerable attention. Inorganic mercury can be methylated by bacterial action and is stored in the muscle tissue of fish. When ingested by man, it can attack the central nervous system. The US Environmental Protection Agency has already set stringent guidelines for the maximum dietary intake of methyl mercury (0.1 μg/kg/day). Up to 10 million people are involved in the use of mercury in gold exploitation which constitutes a significant pollution source in some countries. The biogeochemistry of mercury and the mercury cycle were reviewed. Long range atmospheric transfer mechanisms have led to significant contamination of fish in lakes remote from any pollution source. The value of stable or radioactive isotopic tracers in understanding the mercury cycle was pointed out and the need for relevant natural matrix reference materials for quality control and method development purposes was stressed

  18. Spatial, Temporal, and Dietary Variables Associated with Elevated Mercury Exposure in Peruvian Riverine Communities Upstream and Downstream of Artisanal and Small-Scale Gold Mining

    Directory of Open Access Journals (Sweden)

    Lauren Wyatt

    2017-12-01

    Full Text Available Artisanal and small-scale gold mining (ASGM is a primary contributor to global mercury and its rapid expansion raises concern for human exposure. Non-occupational exposure risks are presumed to be strongly tied to environmental contamination; however, the relationship between environmental and human mercury exposure, how exposure has changed over time, and risk factors beyond fish consumption are not well understood in ASGM settings. In Peruvian riverine communities (n = 12, where ASGM has increased 4–6 fold over the past decade, we provide a large-scale assessment of the connection between environmental and human mercury exposure by comparing total mercury contents in human hair (2-cm segment, n = 231 to locally caught fish tissue, analyzing temporal exposure in women of child bearing age (WCBA, 15–49 years, n = 46 over one year, and evaluating general mercury exposure risks including fish and non-fish dietary items through household surveys and linear mixed models. Calculations of an individual’s oral reference dose using the total mercury content in locally-sourced fish underestimated the observed mercury exposure for individuals in many communities. This discrepancy was particularly evident in communities upstream of ASGM, where mercury levels in river fish, water, and sediment measurements from a previous study were low, yet hair mercury was chronically elevated. Hair from 86% of individuals and 77% of children exceeded a USEPA (U.S. Environmental Protection Agency provisional level (1.2 µg/g that could result in child developmental impairment. Chronically elevated mercury exposure was observed in the temporal analysis in WCBA. If the most recent exposure exceeded the USEPA level, there was a 97% probability that the individual exceeded that level 8–10 months of the previous year. Frequent household consumption of some fruits (tomato, banana and grains (quinoa was significantly associated with 29–75% reductions in hair mercury

  19. Spatial, Temporal, and Dietary Variables Associated with Elevated Mercury Exposure in Peruvian Riverine Communities Upstream and Downstream of Artisanal and Small-Scale Gold Mining.

    Science.gov (United States)

    Wyatt, Lauren; Ortiz, Ernesto J; Feingold, Beth; Berky, Axel; Diringer, Sarah; Morales, Ana Maria; Jurado, Elvis Rojas; Hsu-Kim, Heileen; Pan, William

    2017-12-15

    Artisanal and small-scale gold mining (ASGM) is a primary contributor to global mercury and its rapid expansion raises concern for human exposure. Non-occupational exposure risks are presumed to be strongly tied to environmental contamination; however, the relationship between environmental and human mercury exposure, how exposure has changed over time, and risk factors beyond fish consumption are not well understood in ASGM settings. In Peruvian riverine communities ( n = 12), where ASGM has increased 4-6 fold over the past decade, we provide a large-scale assessment of the connection between environmental and human mercury exposure by comparing total mercury contents in human hair (2-cm segment, n = 231) to locally caught fish tissue, analyzing temporal exposure in women of child bearing age (WCBA, 15-49 years, n = 46) over one year, and evaluating general mercury exposure risks including fish and non-fish dietary items through household surveys and linear mixed models. Calculations of an individual's oral reference dose using the total mercury content in locally-sourced fish underestimated the observed mercury exposure for individuals in many communities. This discrepancy was particularly evident in communities upstream of ASGM, where mercury levels in river fish, water, and sediment measurements from a previous study were low, yet hair mercury was chronically elevated. Hair from 86% of individuals and 77% of children exceeded a USEPA (U.S. Environmental Protection Agency) provisional level (1.2 µg/g) that could result in child developmental impairment. Chronically elevated mercury exposure was observed in the temporal analysis in WCBA. If the most recent exposure exceeded the USEPA level, there was a 97% probability that the individual exceeded that level 8-10 months of the previous year. Frequent household consumption of some fruits (tomato, banana) and grains (quinoa) was significantly associated with 29-75% reductions in hair mercury. Collectively, these

  20. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-456 Marine Sediment Samples

    International Nuclear Information System (INIS)

    2016-01-01

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioisotope analytical techniques to understand, monitor and protect the environment. In this context, the major impact of large coastal cities on marine ecosystems is an issue of prime concern for the IAEA and the IAEA Environment Laboratories. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. The IAEA Environment Laboratories has been assisting national laboratories and regional laboratory networks since the early 1970s through the provision of a reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Quality assurance, quality control and associated good laboratory practice are essential components of all marine environmental monitoring studies. Quality control procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess t h e reliability and comparability of measurement data. Data that are not based on adequate quality assurance and quality control can be erroneous, and their misuse can lead to poor environmental management decisions. A marine sediment sample with certified mass amount contents for aluminium, arsenic, cadmium chromium, cobalt, copper, iron, lead, mercury, methyl mercury, manganese, nickel, vanadium and zinc was recently produced by the IAEA Environment Laboratories. This publication presents the sample preparation methodology, including material homogeneity and the stability study, the selection of laboratories, the evaluation of results from the certification campaign, and the assignment of property values and their associated uncertainty. As a result, certified values for mass fractions and associated expanded uncertainty were

  1. Study of spatiotemporal variation of atmospheric mercury and its human exposure around an integrated steel plant, India

    Science.gov (United States)

    Pervez, S.; Koshle, A.; Pervez, Y.

    2010-06-01

    Mercury release by coal combustion has been significantly increased in India. Mercury content in coal has been analyzed to 0.272 ppm by Central Pollution Control Board. Toxicological effects of elemental Hg (Hg0) exposure include respiratory and renal failures, cardiac arrest, and cerebral oedema, while subclinical exposure may induce kidney, behavioral, and cognitive dysfunctions. The present work is focused on dispersion pattern and inter-phase exchange phenomena of ambient mercury between air-particulate matter evaluations of alongwith dominance of various major routes of human exposure-dose response using regression analysis around an integrated steel plant in central India. Source-downwind type stratified random sampling plan using longitudinal study design has been adopted for ambient monitoring of total mercury, while representative sampling plant has been adopted for persona exposure-dose response study In space-time framework. Control sites and subjects have been chosen from uncontaminated area (100 km away from any industrial activities). 06 ambient air monitoring stations and 17 subjects from workers, non-workers but local residents' categories and from controlled sites have been chosen for the study. Samples of mercury biomarkers (blood, breast milk and urine) have also been collected from same subjects in each month during sampling period. The sampling period was March 2005 to February 2006 . Samples of 30% acidified KMnO4 for air-Hg absorption, PM10, RPM and biological samples were analyzed for total mercury by ICP-AES using standard methods. Local soils and ground water were also monitored for total mercury content during the sampling period. Results have shown that mercury concentration is very high compared to prescribed limits in all receptors. Results of exchange phenomenon have shown the higher transfer of mercury from air to particulate during combustion in steel plant environment due to presence of huge amount of iron particles, in contrast to

  2. Mercury in human brain, blood, muscle and toenails in relation to exposure: an autopsy study

    Directory of Open Access Journals (Sweden)

    Morild Inge

    2007-10-01

    Full Text Available Abstract Background The main forms of mercury (Hg exposure in the general population are methylmercury (MeHg from seafood, inorganic mercury (I-Hg from food, and mercury vapor (Hg0 from dental amalgam restorations. While the distribution of MeHg in the body is described by a one compartment model, the distribution of I-Hg after exposure to elemental mercury is more complex, and there is no biomarker for I-Hg in the brain. The aim of this study was to elucidate the relationships between on the one hand MeHg and I-Hg in human brain and other tissues, including blood, and on the other Hg exposure via dental amalgam in a fish-eating population. In addition, the use of blood and toenails as biological indicator media for inorganic and organic mercury (MeHg in the tissues was evaluated. Methods Samples of blood, brain (occipital lobe cortex, pituitary, thyroid, abdominal muscle and toenails were collected at autopsy of 30 deceased individuals, age from 47 to 91 years of age. Concentrations of total-Hg and I-Hg in blood and brain cortex were determined by cold vapor atomic fluorescence spectrometry and total-Hg in other tissues by sector field inductively coupled plasma-mass spectrometry (ICP-SFMS. Results The median concentrations of MeHg (total-Hg minus I-Hg and I-Hg in blood were 2.2 and 1.0 μg/L, and in occipital lobe cortex 4 and 5 μg/kg, respectively. There was a significant correlation between MeHg in blood and occipital cortex. Also, total-Hg in toenails correlated with MeHg in both blood and occipital lobe. I-Hg in both blood and occipital cortex, as well as total-Hg in pituitary and thyroid were strongly associated with the number of dental amalgam surfaces at the time of death. Conclusion In a fish-eating population, intake of MeHg via the diet has a marked impact on the MeHg concentration in the brain, while exposure to dental amalgam restorations increases the I-Hg concentrations in the brain. Discrimination between mercury species is

  3. Public health benefits of hair-mercury analysis and dietary advice in lowering methylmercury exposure in pregnant women.

    Science.gov (United States)

    Kirk, Line E; Jørgensen, Jan S; Nielsen, Flemming; Grandjean, Philippe

    2017-06-01

    To evaluate whether a public health intervention using focused dietary advice combined with a hair-mercury analysis can lower neurotoxic methylmercury exposure among pregnant women without decreasing their overall intake of seafood. A total of 146 pregnant women were consecutively recruited from the antenatal clinic at a Danish university hospital at their initial ultrasound scan. Dietary advice was provided on avoiding methylmercury exposure from large predatory fish and a hair sample from each participant was analysed for mercury, with the results being communicated shortly thereafter to the women. A dietary questionnaire was filled in. Follow-up three months later included a dietary questionnaire and a repeat hair-mercury analysis. In the follow-up group, 22% of the women had hair-mercury concentrations above a safe limit of 0.58 µg/g at enrolment, decreasing to 8% three months later. Average hair-mercury concentrations decreased by 21%. However, the total seafood intake remained at the same level after three months. Increased exposure to methylmercury among pregnant women is an important public health concern in Denmark. The observed lowering of hair-mercury concentrations associated with dietary advice corresponds to a substantial public health benefit that probably makes such an intervention highly profitable.

  4. Epidemiologic confirmation that fruit consumption influences mercury exposure in riparian communities in the Brazilian Amazon

    International Nuclear Information System (INIS)

    Sousa Passos, Carlos Jose; Mergler, Donna; Fillion, Myriam; Lemire, Melanie; Mertens, Frederic; Guimaraes, Jean Remy Davee; Philibert, Aline

    2007-01-01

    Since deforestation has recently been associated with increased mercury load in the Amazon, the problem of mercury exposure is now much more widespread than initially thought. A previous exploratory study suggested that fruit consumption may reduce mercury exposure. The objectives of the study were to determine the effects of fruit consumption on the relation between fish consumption and bioindicators of mercury (Hg) exposure in Amazonian fish-eating communities. A cross-sectional dietary survey based on a 7-day recall of fish and fruit consumption frequency was conducted within 13 riparian communities from the Tapajos River, Brazilian Amazon. Hair samples were collected from 449 persons, and blood samples were collected from a subset of 225, for total and inorganic mercury determination by atomic absorption spectrometry. On average, participants consumed 6.6 fish meals/week and ate 11 fruits/week. The average blood Hg (BHg) was 57.1±36.3 μg/L (median: 55.1 μg/L), and the average hair-Hg (HHg) was 16.8±10.3 μg/g (median: 15.7 μg/g). There was a positive relation between fish consumption and BHg (r=0.48; P 2 =36.0%) and HHg levels (fish: β=1.2, P 2 =21.0%). ANCOVA models showed that for the same number of fish meals, persons consuming fruits more frequently had significantly lower blood and HHg concentrations. For low fruit consumers, each fish meal contributed 9.8 μg/L Hg increase in blood compared to only 3.3 μg/L Hg increase for the high fruit consumers. In conclusion, fruit consumption may provide a protective effect for Hg exposure in Amazonian riparians. Prevention strategies that seek to maintain fish consumption while reducing Hg exposure in fish-eating communities should be pursued

  5. Mercury in Your Environment

    Science.gov (United States)

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

  6. Mercury and Your Health

    Science.gov (United States)

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

  7. Microbiology and biogeochemistry of sediments and rhizosphere of mangroves: bacterial production, sulphate-reduction and methylation of mercury with methodological focus on incubation-extraction of 14C-leucine

    International Nuclear Information System (INIS)

    Feijo, Issabella Vitoria Abduche

    2015-01-01

    Mangroves are one of the most important ecosystems when it comes to cycling of various elements, including carbon and mercury. Microbiological processes that occur in sediment are essential for carbon mineralization, its conversion into biomass and for availability of mercury to the food chain. Sulfate-reducing bacteria are one of the main groups responsible for degradation of organic compounds in marine sediments and mercury methylation, especially in the rhizosphere of macrophyte. The aim of this study was to evaluate bacterial production (BP) over different sedimentary profiles as well as mercury methylation (% MeHg), sulfate reduction rates (SRR) and bacterial production in the rhizosphere of a ubiquitous mangrove tree. Radiochemical approaches were used to access bacterial production ( 14 C-leucine), sulfate reduction ( 35 SO 4 ) and mercury methylation ( 203 Hg). Study area was located at Coroa Grande (Sepetiba bay) and Jequia mangrove (Guanabara bay). Methodological studies using 14 C-leucine as a tool to assess bacterial production in mangrove sediment were not found. In this context, we tested two leucine uptake methodologies for measuring bacterial production in mangrove sediments according to Baath et al. (2001) Soil Biol. Biochem., v.33,p. 1571-1574 and Fischer and Pusch (1999) Appl. Environ. Microbiol., v.6, p.4411-4418. Our results suggest that an adaptation of both techniques were suitable to measure BP in mangrove sediment. We also provided underlying parameters of the method such as saturation level and linearity of leucine incorporation that can be used as guidance for future studies in mangrove. Once the methodology was established, we accessed BP along a shallow sedimentary profile in three physiographic mangroves types: basin, fringe and riverine. BP was highly heterogeneous in different physiographic types of mangroves and along the sediment profiles.The mangrove located at Guanabara bay presented BP which was 50 times higher than tho one

  8. Environmental and human exposure assessment monitoring of communities near an abandoned mercury mine in the Philippines: a toxic legacy.

    Science.gov (United States)

    Maramba, Nelia P C; Reyes, Jose Paciano; Francisco-Rivera, Ana Trinidad; Panganiban, Lynn Crisanta R; Dioquino, Carissa; Dando, Nerissa; Timbang, Rene; Akagi, Hirokatsu; Castillo, Ma Teresa; Quitoriano, Carmela; Afuang, Maredith; Matsuyama, Akito; Eguchi, Tomomi; Fuchigami, Youko

    2006-10-01

    sites, namely Tagburos and Honda Bay, exceeded the EPA Region 9 Primary Remediation Goal recommended values for total mercury for residential purposes (NV>23 mg/kg). The hand to mouth activity among infants and children is another significant route for mercury exposure. Statistically significant results were obtained for infants when comparing the results after one year of monitoring for methylmercury levels in hair for both exposed and control sub-groups. Likewise, comparing the initial and final hair methylmercury levels among pregnant women/mothers in the exposed group showed statistically significant (p<0.05) results. Comparing the exposed and control sub-groups' mercury hair levels per sub-group showed statistically significant results among the following: (a) initial and final total mercury hair levels among children, (b) initial and final methylmercury hair levels among children, (c) final total mercury hair levels among pregnant women, (d) initial and final total mercury hair levels among mothers, and (e) initial and final methyl hair levels among mothers.

  9. Population-based inorganic mercury biomonitoring and the identification of skin care products as a source of exposure in New York City.

    Science.gov (United States)

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

    2011-02-01

    Mercury is a toxic metal that has been used for centuries as a constituent of medicines and other items. We assessed exposure to inorganic mercury in the adult population of New York City (NYC). 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. 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. 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.

  10. Cytogenetic damage related to low levels of methyl mercury contamination in the Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    MARÚCIA I. M. AMORIM

    2000-12-01

    Full Text Available The mercury rejected in the water system, from mining operations and lixiviation of soils after deforestation, is considered to be the main contributors to the contamination of the ecosystem in the Amazon Basin. The objectives of the present study were to examine cytogenetic functions in peripheral lymphocytes within a population living on the banks of the Tapajós River with respect to methylmercury (MeHg contamination, using hair mercury as a biological indicator of exposure. Our investigation shows a clear relation between methylmercury contamination and cytogenetic damage in lymphocytes at levels well below 50 micrograms/gram, the level at which initial clinical signs and symptoms of mercury poisoning occur. The first apparent biological effect with increasing MeHg hair level was the impairment of lymphocyte proliferation measured as mitotic index (MI. The relation between mercury concentration in hair and MI suggests that this parameter, an indicator of changes in lymphocytes and their ability to respond to culture conditions, may be an early marker of cytotoxicity and genotoxicity in humans and should be taken into account in the preliminary evaluation of the risks to populations exposed in vivo. This is the first report showing clear cytotoxic effects of long-term exposure to MeHg. Although the results strongly suggest that, under the conditions examined here, MeHg is both a spindle poison and a clastogen, the biological significance of these observations are as yet unknown. A long-term follow-up of these subjects should be undertaken.

  11. Are one or two dangerous? Methyl salicylate exposure in toddlers.

    Science.gov (United States)

    Davis, Jonathan E

    2007-01-01

    Serious toxicity can result from exposure to small amounts of methyl salicylate. Methyl salicylate is widely available as a component in many over-the-counter brands of creams, ointments, lotions, liniments and medicated oils intended for topical application to relieve musculoskeletal aches and pains. Among the most potent forms of methyl salicylate is oil of wintergreen (98% methyl salicylate). Other products with varying concentrations of methyl salicylate are ubiquitous throughout many parts of the world, including a number of products marketed as Asian herbal remedies. The toxic potential of all of these formulations is often underestimated by health care providers and the general public. A comprehensive review of the existing medical literature on methyl salicylate poisoning was performed, and data compiled over the past two decades by the American Association of Poison Control Centers (AAPCC) was examined. Methyl salicylate continues to be a relatively common source of pediatric exposures. Persistent reports of life-threatening and fatal toxicity were found. In children less than 6 years of age, a teaspoon (5 mL) or less of oil of wintergreen has been implicated in several well-documented deaths. More needs to be done to educate both health care providers and the general public regarding the dangers of these widely available formulations.

  12. Environmental mercury contamination in China: Sources and impacts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L; Wong, M H [Hong Kong Baptist University, Hong Kong (China)

    2007-01-15

    This review article focused on the current status of mercury (Hg) contamination in different ecological compartments in China, and their possible environmental and health impacts, focusing on some major cities. Mercury emission from non-ferrous metals smelting (especially zinc smelting), coal combustion and miscellaneous activities (of which battery and fluorescent lamp production and cement production are the largest), contributed about 45%, 38% and 17%, respectively, to the total Hg emission based on the data of 1999. Mercury contamination is widespread in different ecological compartments such as atmosphere, soil and water. There is evidence showing bioaccumulation and biomagnification of Hg in aquatic food chains, with higher concentrations detected in carnivorous fish. In terms of human exposure to Hg, fish consumption is the major exposure pathway for residents living in coastal cities such as Hong Kong, but inhalation may be another major source, affecting human health in areas with severe atmospheric Hg, such as Guiyang City (Guizhou Province). There is also increasing evidence showing that skin disorders and autism in Hong Kong children are related to their high Hg body loadings (hair, blood and urine), through prenatal methyl Hg exposure. There seems to be an urgent need to identify the sources of Hg, speciation and concentrations in different ecological compartments, which may lead to high body loadings in human beings.

  13. Mercury exposure, nutritional deficiencies and metabolic disruptions may affect learning in children

    Directory of Open Access Journals (Sweden)

    Patrick Lyn

    2009-10-01

    Full Text Available Abstract Among dietary factors, learning and behavior are influenced not only by nutrients, but also by exposure to toxic food contaminants such as mercury that can disrupt metabolic processes and alter neuronal plasticity. Neurons lacking in plasticity are a factor in neurodevelopmental disorders such as autism and mental retardation. Essential nutrients help maintain normal neuronal plasticity. Nutritional deficiencies, including deficiencies in the long chain polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid, the amino acid methionine, and the trace minerals zinc and selenium, have been shown to influence neuronal function and produce defects in neuronal plasticity, as well as impact behavior in children with attention deficit hyperactivity disorder. Nutritional deficiencies and mercury exposure have been shown to alter neuronal function and increase oxidative stress among children with autism. These dietary factors may be directly related to the development of behavior disorders and learning disabilities. Mercury, either individually or in concert with other factors, may be harmful if ingested in above average amounts or by sensitive individuals. High fructose corn syrup has been shown to contain trace amounts of mercury as a result of some manufacturing processes, and its consumption can also lead to zinc loss. Consumption of certain artificial food color additives has also been shown to lead to zinc deficiency. Dietary zinc is essential for maintaining the metabolic processes required for mercury elimination. Since high fructose corn syrup and artificial food color additives are common ingredients in many foodstuffs, their consumption should be considered in those individuals with nutritional deficits such as zinc deficiency or who are allergic or sensitive to the effects of mercury or unable to effectively metabolize and eliminate it from the body.

  14. Mercury exposure and risk of hypertension in US men and women in 2 prospective cohorts

    DEFF Research Database (Denmark)

    Mozaffarian, Dariush; Shi, Peilin; Morris, J Steven

    2012-01-01

    Cross-sectional studies and animal experiments suggest that methylmercury exposure could increase the risk of hypertension. This relationship has not been evaluated in large prospective studies. Using data from previous nested case-control studies in 2 separate prospective cohorts, we measured...... toenail mercury, a valid biomarker of long-term methylmercury exposure, among 6045 US men and women free of hypertension at baseline. Geometric mean toenail mercury concentrations were 0.08 μg/g in the lowest quintile and 0.74 μg/g in the highest quintile, the latter corresponding with exposures ≈2.0-fold.......82 (0.62-1.08) in men, and 0.94 (0.84-1.06) in both cohorts combined. Findings were similar when more extreme categories of mercury were compared (across deciles, with geometric mean levels in highest decile ≈2.9-fold higher than the reference dose) and in analyses stratified by fish or omega-3...

  15. Impact of the Sainte-Marguerite 3 hydroelectric reservoir on the mercury exposure of local fish consumers

    International Nuclear Information System (INIS)

    Schetagne, R.; Plante, M.; Castonguay, D.

    2010-01-01

    This study examined fish mercury levels in a freshwater impoundment flooded as part of the Sainte-Marguerite-3 hydroelectric generating station. The study compared mercury levels obtained before the area was flooded in 1997 with mercury exposure surveys obtained in 2006. Mercury levels in the fish have increased by factors ranging from 4 to 8. Total mercury concentrations have reached 0.78 μg per g in 400-mm lake whitefish and 1.85 μg per g in 700-mm northern pike. Non-native fishers consumed significantly more local fish on a monthly basis after the area was flooded. Native Innu fishers consumed less fish. Average hair mercury concentrations for non-native fish consumers remained unchanged, which mercury levels in native fish consumers decreased significantly.

  16. Neuropsychological dysfunction related to earlier occupational exposure to mercury vapor

    Directory of Open Access Journals (Sweden)

    E.C. Zachi

    2007-03-01

    Full Text Available We assessed the neuropsychological test performances of 26 patients (mean age = 41.5 ± 6.1 years; mean years of education = 9.8 ± 1.8; 20 males diagnosed with chronic occupational mercurialism who were former workers at a fluorescent lamp factory. They had been exposed to elemental mercury for an average of 10.2 ± 3.8 years and had been away from this work for 6 ± 4.7 years. Mean urinary mercury concentrations 1 year after cessation of work were 1.8 ± 0.9 µg/g creatinine. Twenty control subjects matched for age, gender, and education (18 males were used for comparison. Neuropsychological assessment included attention, inhibitory control, verbal and visual memory, verbal fluency, manual dexterity, visual-spatial function, executive function, and semantic knowledge tests. The Beck Depression Inventory and the State and Trait Inventory were used to assess depression and anxiety symptoms, respectively. The raw score for the group exposed to mercury indicated slower information processing speed, inferior performance in psychomotor speed, verbal spontaneous recall memory, and manual dexterity of the dominant hand and non-dominant hand (P < 0.05. In addition, the patients showed increased depression and anxiety symptoms (P < 0.001. A statistically significant correlation (Pearson was demonstrable between mean urinary mercury and anxiety trait (r = 0.75, P = 0.03. The neuropsychological performances of the former workers suggest that occupational exposure to elemental mercury has long-term effects on information processing and psychomotor function, with increased depression and anxiety also possibly reflecting the psychosocial context.

  17. Distribution of total mercury, methyl mercury and selenium in pod of killer whales (Orcinus Orca) stranded in the northern area of Japan: Comparison of mature females with calves

    International Nuclear Information System (INIS)

    Endo, Tetsuya; Kimura, Osamu; Hisamichi, Yohsuke; Minoshima, Yasuhiko; Haraguchi, Koichi; Kakumoto, Chiharu; Kobayashi, Mari

    2006-01-01

    Total mercury (T-Hg) and selenium (Se) concentrations in liver, kidney and muscle from a pod of killer whales including five mature females and three calves stranded in the northern area of Japan were analyzed. In the mature female, contamination level of T-Hg in the liver sample (62.2 ± 21.9 μg/wet g) was markedly higher than that in kidney sample and muscle sample. The molar ratio of T-Hg to Se in the liver sample was approximately 1, and those in the kidney and muscle samples were markedly lower than 1. These results suggest that the formation of HgSe compound increases the hepatic accumulation of mercury (Hg). In contrast, contamination level of T-Hg in the calf organs was much lower than that in the mature female organs. These results suggest that the transfer of Hg from the mother to the fetus via placenta and/or to calf via milk is trace. - Total mercury, methyl mercury and selenium concentrations in liver, kidney and muscle from a pod of killer whales stranded in the northern area of Japan were analyzed

  18. Distribution of total mercury, methyl mercury and selenium in pod of killer whales (Orcinus Orca) stranded in the northern area of Japan: Comparison of mature females with calves

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Tetsuya [Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, 1757 Ishikari-Tobetsu, Hokkaido 061-0293 (Japan)]. E-mail: endotty@hoku-iryo-u.ac.jp; Kimura, Osamu [Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, 1757 Ishikari-Tobetsu, Hokkaido 061-0293 (Japan); Hisamichi, Yohsuke [Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, 1757 Ishikari-Tobetsu, Hokkaido 061-0293 (Japan); Minoshima, Yasuhiko [Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, 1757 Ishikari-Tobetsu, Hokkaido 061-0293 (Japan); Haraguchi, Koichi [Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-Cho, Minami-Ku, Fukuoka 815-8511 (Japan); Kakumoto, Chiharu [Marine Wildlife Center of JAPAN - Incorporated Non Profit Organization/NPO, 1-35-103, N21W6 Kita-ku, Sapporo, Hokkaido 001-0021 (Japan); Kobayashi, Mari [Marine Wildlife Center of JAPAN - Incorporated Non Profit Organization/NPO, 1-35-103, N21W6 Kita-ku, Sapporo, Hokkaido 001-0021 (Japan)

    2006-11-15

    Total mercury (T-Hg) and selenium (Se) concentrations in liver, kidney and muscle from a pod of killer whales including five mature females and three calves stranded in the northern area of Japan were analyzed. In the mature female, contamination level of T-Hg in the liver sample (62.2 {+-} 21.9 {mu}g/wet g) was markedly higher than that in kidney sample and muscle sample. The molar ratio of T-Hg to Se in the liver sample was approximately 1, and those in the kidney and muscle samples were markedly lower than 1. These results suggest that the formation of HgSe compound increases the hepatic accumulation of mercury (Hg). In contrast, contamination level of T-Hg in the calf organs was much lower than that in the mature female organs. These results suggest that the transfer of Hg from the mother to the fetus via placenta and/or to calf via milk is trace. - Total mercury, methyl mercury and selenium concentrations in liver, kidney and muscle from a pod of killer whales stranded in the northern area of Japan were analyzed.

  19. Environmental mercury exposure, semen quality and reproductive hormones in Greenlandic Inuit and European men

    DEFF Research Database (Denmark)

    Mocevic, Emina; Specht, Ina O; Marott, Jacob Louis

    2013-01-01

    Several animal studies indicate that mercury is a male reproductive toxicant, but human studies are few and contradictory. We examined semen characteristics and serum levels of reproductive hormones in relation to environmental exposure to mercury. Blood and semen samples were collected from 529.......024 to 0.110). The association may be due to beneficial effects of polyunsaturated fatty acids (PUFAs), which are contained in seafood and fish. No significant association (P>0.05) was found between blood concentrations of mercury and any of the other measured semen characteristics (semen volume, total...

  20. Mercury exposure in a high fish eating Bolivian Amazonian population with intense small-scale gold-mining activities.

    Science.gov (United States)

    Barbieri, Flavia Laura; Cournil, Amandine; Gardon, Jacques

    2009-08-01

    Methylmercury exposure in Amazonian communities through fish consumption has been widely documented in Brazil. There is still a lack of data in other Amazonian countries, which is why we conducted this study in the Bolivian Amazon basin. Simple random sampling was used from a small village located in the lower Beni River, where there is intense gold mining and high fish consumption. All participants were interviewed and hair samples were taken to measure total mercury concentrations. The hair mercury geometric mean in the general population was 3.02 microg/g (CI: 2.69-3.37; range: 0.42-15.65). Age and gender were not directly associated with mercury levels. Fish consumption showed a positive relation and so did occupation, especially small-scale gold mining. Hair mercury levels were lower than those found in Brazilian studies, but still higher than in non-exposed populations. It is necessary to assess mercury exposure in the Amazonian regions where data is still lacking, using a standardized indicator.

  1. Public health benefits of hair-mercury analysis and dietary advice in lowering methylmercury exposure in pregnant women

    DEFF Research Database (Denmark)

    Kirk, Line E; Jørgensen, Jan S; Nielsen, Flemming

    2017-01-01

    recruited from the antenatal clinic at a Danish university hospital at their initial ultrasound scan. Dietary advice was provided on avoiding methylmercury exposure from large predatory fish and a hair sample from each participant was analysed for mercury, with the results being communicated shortly......AIMS: To evaluate whether a public health intervention using focused dietary advice combined with a hair-mercury analysis can lower neurotoxic methylmercury exposure among pregnant women without decreasing their overall intake of seafood. METHODS: A total of 146 pregnant women were consecutively......% three months later. Average hair-mercury concentrations decreased by 21%. However, the total seafood intake remained at the same level after three months. CONCLUSIONS: Increased exposure to methylmercury among pregnant women is an important public health concern in Denmark. The observed lowering of hair...

  2. Immunotoxicity of environmentally relevant mixtures of polychlorinated aromatic hydrocarbons with methyl mercury on rat lymphocytes in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Omara, F.O.; Brochu, C.; Flipo, D.; Denizeau, F.; Fournier, M. [Univ. of Quebec, Montreal, Quebec (Canada)

    1997-03-01

    The immunosuppressive effects of methyl mercury (MHg), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) are well established at higher exposure levels but unclear at low exposure levels. The authors exposed Fischer 344 rat splenocytes, thymocytes, and peripheral blood lymphocytes in vitro for 72 h to MHg of three PCDDs and two PCDFs PCB mixtures, or combinations of MHg/PCB/PCDD/PCDF mixtures Mitogenic responses of lymphocytes to concanavalin A, phytohemagglutinin, or lipopolysaccharide/dextran sulfate were determined by {sup 3}H-thymidine uptake; cytotoxicity and intracellular Ca{sup 2+} were determined by flow cytometry. Methylmercury mixtures with 2 {micro}g/ml MHg decreased the viability of splenocytes to 57 and 40% at 4 and 24 h, respectively. Basal intracellular calcium ion levels were unaffected by the treatments. Methylmercury suppressed the responses of lymphocytes to T and B cell mitogens. All combinations of MHg/PCB/PCDD/PCDF mixtures decreased mitogenic responses to levels similar to those to MHg alone. In contrast, PCB and PCDD/PCDF mixtures did not suppress but augmented responses of splenocytes and peripheral blood lymphocytes to T cell mitogens. Overall, no interactive toxicity was observed with MHg/PCB/PCDD/PCDF mixtures on cytotoxicity and lymphocyte mitogenic responses. Therefore, MHg may pose a greater threat than organochlorines to the mammalian immune system.

  3. Mercury methylation and reduction potentials in marine water: An improved methodology using {sup 197}Hg radiotracer

    Energy Technology Data Exchange (ETDEWEB)

    Koron, Neza [National Institute of Biology, Marine Biology Station, Fornace 41, 6330 Piran (Slovenia); Bratkic, Arne [Department of Environmental Sciences, ' Jozef Stefan' Institute, Jamova 39, 1000 Ljubljana (Slovenia); Ribeiro Guevara, Sergio, E-mail: ribeiro@cab.cnea.gov.ar [Laboratorio de Analisis por Activacion Neutronica, Centro Atomico Bariloche, Av. Bustillo km 9.5, 8400 Bariloche (Argentina); Vahcic, Mitja; Horvat, Milena [Department of Environmental Sciences, ' Jozef Stefan' Institute, Jamova 39, 1000 Ljubljana (Slovenia)

    2012-01-15

    A highly sensitive laboratory methodology for simultaneous determination of methylation and reduction of spiked inorganic mercury (Hg{sup 2+}) in marine water labelled with high specific activity radiotracer ({sup 197}Hg prepared from enriched {sup 196}Hg stable isotope) was developed. A conventional extraction protocol for methylmercury (CH{sub 3}Hg{sup +}) was modified in order to significantly reduce the partitioning of interfering labelled Hg{sup 2+} into the final extract, thus allowing the detection of as little as 0.1% of the Hg{sup 2+} spike transformed to labelled CH{sub 3}Hg{sup +}. The efficiency of the modified CH{sub 3}Hg{sup +} extraction procedure was assessed by radiolabelled CH{sub 3}Hg{sup +} spikes corresponding to concentrations of methylmercury between 0.05 and 4 ng L{sup -1}. The recoveries were 73.0{+-}6.0% and 77.5{+-}3.9% for marine and MilliQ water, respectively. The reduction potential was assessed by purging and trapping the radiolabelled elemental Hg in a permanganate solution. The method allows detection of the reduction of as little as 0.001% of labelled Hg{sup 2+} spiked to natural waters. To our knowledge, the optimised methodology is among the most sensitive available to study the Hg methylation and reduction potential, therefore allowing experiments to be done at spikes close to natural levels (1-10 ng L{sup -1}). - Highlights: Black-Right-Pointing-Pointer Inorganic mercury methylation and reduction in marine water were studied. Black-Right-Pointing-Pointer High specific activity {sup 197}Hg was used to label Hg{sup 2+} spikes at natural levels. Black-Right-Pointing-Pointer Methylmercury extraction had 73% efficiency for 0.05-4 ng L{sup -1} levels. Black-Right-Pointing-Pointer High sensibility to assess methylation potentials, below 0.1% of the spike. Black-Right-Pointing-Pointer High sensibility also for reduction potentials, as low as 0.001% of the spike.

  4. Rice methylmercury exposure and mitigation: a comprehensive review

    Science.gov (United States)

    Rothenberg, Sarah E.; Windham-Myers, Lisamarie; Creswell, Joel E.

    2014-01-01

    Rice cultivation practices from field preparation to post-harvest transform rice paddies into hot spots for microbial mercury methylation, converting less-toxic inorganic mercury to more-toxic methylmercury, which is likely translocated to rice grain. This review includes 51 studies reporting rice total mercury and/or methylmercury concentrations, based on rice (Orzya sativa) cultivated or purchased in 15 countries. Not surprisingly, both rice total mercury and methylmercury levels were significantly higher in polluted sites compared to non-polluted sites (Wilcoxon rank sum, price percent methylmercury (of total mercury) did not differ statistically between polluted and non-polluted sites (Wilcoxon rank sum, p=0.35), suggesting comparable mercury methylation rates in paddy soil across these sites and/or similar accumulation of mercury species for these rice cultivars. Studies characterizing the effects of rice cultivation under more aerobic conditions were reviewed to determine the mitigation potential of this practice. Rice management practices utilizing alternating wetting and drying (instead of continuous flooding) caused soil methylmercury levels to spike, resulting in a strong methylmercury pulse after fields were dried and reflooded; however, it is uncertain whether this led to increased translocation of methylmercury from paddy soil to rice grain. Due to the potential health risks, it is advisable to investigate this issue further, and to develop separate water management strategies for mercury polluted and non-polluted sites, in order to minimize methylmercury exposure through rice ingestion.

  5. Rice methylmercury exposure and mitigation: a comprehensive review.

    Science.gov (United States)

    Rothenberg, Sarah E; Windham-Myers, Lisamarie; Creswell, Joel E

    2014-08-01

    Rice cultivation practices from field preparation to post-harvest transform rice paddies into hot spots for microbial mercury methylation, converting less-toxic inorganic mercury to more-toxic methylmercury, which is likely translocated to rice grain. This review includes 51 studies reporting rice total mercury and/or methylmercury concentrations, based on rice (Orzya sativa) cultivated or purchased in 15 countries. Not surprisingly, both rice total mercury and methylmercury levels were significantly higher in polluted sites compared to non-polluted sites (Wilcoxon rank sum, p<0.001). However, rice percent methylmercury (of total mercury) did not differ statistically between polluted and non-polluted sites (Wilcoxon rank sum, p=0.35), suggesting comparable mercury methylation rates in paddy soil across these sites and/or similar accumulation of mercury species for these rice cultivars. Studies characterizing the effects of rice cultivation under more aerobic conditions were reviewed to determine the mitigation potential of this practice. Rice management practices utilizing alternating wetting and drying (instead of continuous flooding) caused soil methylmercury levels to spike, resulting in a strong methylmercury pulse after fields were dried and reflooded; however, it is uncertain whether this led to increased translocation of methylmercury from paddy soil to rice grain. Due to the potential health risks, it is advisable to investigate this issue further, and to develop separate water management strategies for mercury polluted and non-polluted sites, in order to minimize methylmercury exposure through rice ingestion. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Mercury Exposure Assessment and Spatial Distribution in A Ghanaian Small-Scale Gold Mining Community.

    Science.gov (United States)

    Rajaee, Mozhgon; Long, Rachel N; Renne, Elisha P; Basu, Niladri

    2015-09-01

    Mercury is utilized worldwide in artisanal and small-scale gold mining (ASGM) and may pose a risk for miners and mining communities. While a number of studies have characterized mercury in ASGM communities, most have focused on a single media and few have taken a holistic approach. Here, a multiple media exposure assessment and cross-sectional study of mercury was conducted in 2010 through 2012 in northeast Ghana with a small-scale gold mining community, Kejetia, a subsistence farming community, Gorogo, and an urban ASGM gold refinery in Bolgatanga. The objective was to assess mercury in a range of human (urine and hair) and ecological (household soil, sediment, fish, and ore) samples to increase understanding of mercury exposure pathways. All participants were interviewed on demographics, occupational and medical histories, and household characteristics. Participants included 90 women of childbearing age and 97 adults from Kejetia and 75 adults from Gorogo. Median total specific gravity-adjusted urinary, hair, and household soil mercury were significantly higher in Kejetia miners (5.18 µg/L, 0.967 µg/g, and 3.77 µg/g, respectively) than Kejetia non-miners (1.18 µg/L, 0.419 µg/g, and 2.00 µg/g, respectively) and Gorogo participants (0.154 µg/L, 0.181 µg/g, and 0.039 µg/g) in 2011. Sediment, fish, and ore Hg concentrations were below guideline values. Median soil mercury from the Bolgatanga refinery was very high (54.6 µg/g). Estimated mean mercury ingestion for Kejetia adults from soil and dust exceeded the U.S. Environmental Protection Agency reference dose (0.3 µg Hg/kg·day) for pica (0.409 µg Hg/kg·day) and geophagy (20.5 µg Hg/kg·day) scenarios. Most participants with elevated urinary and household soil mercury were miners, but some non-miners approached and exceeded guideline values, suggesting a health risk for non-mining residents living within these communities.

  7. Mercury Exposure Assessment and Spatial Distribution in A Ghanaian Small-Scale Gold Mining Community

    Directory of Open Access Journals (Sweden)

    Mozhgon Rajaee

    2015-09-01

    Full Text Available Mercury is utilized worldwide in artisanal and small-scale gold mining (ASGM and may pose a risk for miners and mining communities. While a number of studies have characterized mercury in ASGM communities, most have focused on a single media and few have taken a holistic approach. Here, a multiple media exposure assessment and cross-sectional study of mercury was conducted in 2010 through 2012 in northeast Ghana with a small-scale gold mining community, Kejetia, a subsistence farming community, Gorogo, and an urban ASGM gold refinery in Bolgatanga. The objective was to assess mercury in a range of human (urine and hair and ecological (household soil, sediment, fish, and ore samples to increase understanding of mercury exposure pathways. All participants were interviewed on demographics, occupational and medical histories, and household characteristics. Participants included 90 women of childbearing age and 97 adults from Kejetia and 75 adults from Gorogo. Median total specific gravity-adjusted urinary, hair, and household soil mercury were significantly higher in Kejetia miners (5.18 µg/L, 0.967 µg/g, and 3.77 µg/g, respectively than Kejetia non-miners (1.18 µg/L, 0.419 µg/g, and 2.00 µg/g, respectively and Gorogo participants (0.154 µg/L, 0.181 µg/g, and 0.039 µg/g in 2011. Sediment, fish, and ore Hg concentrations were below guideline values. Median soil mercury from the Bolgatanga refinery was very high (54.6 µg/g. Estimated mean mercury ingestion for Kejetia adults from soil and dust exceeded the U.S. Environmental Protection Agency reference dose (0.3 µg Hg/kg·day for pica (0.409 µg Hg/kg·day and geophagy (20.5 µg Hg/kg·day scenarios. Most participants with elevated urinary and household soil mercury were miners, but some non-miners approached and exceeded guideline values, suggesting a health risk for non-mining residents living within these communities.

  8. Mercury Exposure Assessment and Spatial Distribution in A Ghanaian Small-Scale Gold Mining Community

    Science.gov (United States)

    Rajaee, Mozhgon; Long, Rachel N.; Renne, Elisha P.; Basu, Niladri

    2015-01-01

    Mercury is utilized worldwide in artisanal and small-scale gold mining (ASGM) and may pose a risk for miners and mining communities. While a number of studies have characterized mercury in ASGM communities, most have focused on a single media and few have taken a holistic approach. Here, a multiple media exposure assessment and cross-sectional study of mercury was conducted in 2010 through 2012 in northeast Ghana with a small-scale gold mining community, Kejetia, a subsistence farming community, Gorogo, and an urban ASGM gold refinery in Bolgatanga. The objective was to assess mercury in a range of human (urine and hair) and ecological (household soil, sediment, fish, and ore) samples to increase understanding of mercury exposure pathways. All participants were interviewed on demographics, occupational and medical histories, and household characteristics. Participants included 90 women of childbearing age and 97 adults from Kejetia and 75 adults from Gorogo. Median total specific gravity-adjusted urinary, hair, and household soil mercury were significantly higher in Kejetia miners (5.18 µg/L, 0.967 µg/g, and 3.77 µg/g, respectively) than Kejetia non-miners (1.18 µg/L, 0.419 µg/g, and 2.00 µg/g, respectively) and Gorogo participants (0.154 µg/L, 0.181 µg/g, and 0.039 µg/g) in 2011. Sediment, fish, and ore Hg concentrations were below guideline values. Median soil mercury from the Bolgatanga refinery was very high (54.6 µg/g). Estimated mean mercury ingestion for Kejetia adults from soil and dust exceeded the U.S. Environmental Protection Agency reference dose (0.3 µg Hg/kg·day) for pica (0.409 µg Hg/kg·day) and geophagy (20.5 µg Hg/kg·day) scenarios. Most participants with elevated urinary and household soil mercury were miners, but some non-miners approached and exceeded guideline values, suggesting a health risk for non-mining residents living within these communities. PMID:26340636

  9. Mercury in plants and soils of the French-speaking part of Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Quinche, J P; Dvorak, V

    1975-01-01

    Samples of plants and soils from an agricultural (Changins/Nyon), industrial (Monthey) and urban (Le Vallon/Lausanne) area as well as samples from regions remote from the sources of atmospheric pollution have been analyzed for mercury. A contamination by the mercury of samples from the Monthey area could be ascertained. However, the average mercury content of 37 samples of leaves of trees and shrubs collected during fall 1974 in the Monthey area was lower by 53.2% as compared to the average value obtained in 1973;, this fact can be explained by the improved anti-pollution action taken by the chemical industry. No methyl mercury was found in the few samples from Monthey area analyzed for methyl mercury (4 samples of vegetables and one sample of tobacco leaves). On the other hand, all mushrooms, were they gathered in an area close or remote from the sources of mercury pollution, contained traces of methyl mercury (ranging between 1.9 and 28% of the total mercury content). Likewise, 4 samples of lichens gathered in Arolla (Valais) and La Fretaz/Bullet (Jura vaudois), both being remote mountain regions, did contain traces of methyl mercury (between 4.8 and 6.5% of total mercury content). Soils from Changins into which every other year, since 11 years, wheat treated with organomercury fungicides was sown, did not contain more mercury than soil from forests or mountain meadows. Samples of foliage of trees and shrubs from the vicinity of the municipal garbage combustion plant at Vallon (Lausanne) were clearly polluted by mercury. 18 references, 9 tables.

  10. Prenatal phthalate exposure and altered patterns of DNA methylation in cord blood.

    Science.gov (United States)

    Solomon, Olivia; Yousefi, Paul; Huen, Karen; Gunier, Robert B; Escudero-Fung, Maria; Barcellos, Lisa F; Eskenazi, Brenda; Holland, Nina

    2017-07-01

    Epigenetic changes such as DNA methylation may be a molecular mechanism through which environmental exposures affect health. Phthalates are known endocrine disruptors with ubiquitous exposures in the general population including pregnant women, and they have been linked with a number of adverse health outcomes. We examined the association between in utero phthalate exposure and altered patterns of cord blood DNA methylation in 336 Mexican-American newborns. Concentrations of 11 phthalate metabolites were analyzed in maternal urine samples collected at 13 and 26 weeks gestation as a measure of fetal exposure. DNA methylation was assessed using the Infinium HumanMethylation 450K BeadChip adjusting for cord blood cell composition. To identify differentially methylated regions (DMRs) that may be more informative than individual CpG sites, we used two different approaches, DMRcate and comb-p. Regional assessment by both methods identified 27 distinct DMRs, the majority of which were in relation to multiple phthalate metabolites. Most of the significant DMRs (67%) were observed for later pregnancy (26 weeks gestation). Further, 51% of the significant DMRs were associated with the di-(2-ethylhexyl) phthalate metabolites. Five individual CpG sites were associated with phthalate metabolite concentrations after multiple comparisons adjustment (FDR), all showing hypermethylation. Genes with DMRs were involved in inflammatory response (IRAK4 and ESM1), cancer (BRCA1 and LASP1), endocrine function (CNPY1), and male fertility (IFT140, TESC, and PRDM8). These results on differential DNA methylation in newborns with prenatal phthalate exposure provide new insights and targets to explore mechanism of adverse effects of phthalates on human health. Environ. Mol. Mutagen. 58:398-410, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  11. The adaptive response of lichens to mercury exposure involves changes in the photosynthetic machinery

    International Nuclear Information System (INIS)

    Nicolardi, Valentina; Cai, Giampiero; Parrotta, Luigi; Puglia, Michele; Bianchi, Laura; Bini, Luca; Gaggi, Carlo

    2012-01-01

    Lichens are an excellent model to study the bioaccumulation of heavy metals but limited information is available on the molecular mechanisms occurring during bioaccumulation. We investigated the changes of the lichen proteome during exposure to constant concentrations of mercury. We found that most of changes involves proteins of the photosynthetic pathway, such as the chloroplastic photosystem I reaction center subunit II, the oxygen-evolving protein and the chloroplastic ATP synthase β-subunit. This suggests that photosynthesis is a target of the toxic effects of mercury. These findings are also supported by changes in the content of photosynthetic pigments (chlorophyll a and b, and β-carotene). Alterations to the photosynthetic machinery also reflect on the structure of thylakoid membranes of algal cells. Response of lichens to mercury also involves stress-related proteins (such as Hsp70) but not cytoskeletal proteins. Results suggest that lichens adapt to mercury exposure by changing the metabolic production of energy. - Highlights: ► Lichens exposed to Hg° vapors accumulate this metal irreversibly. ► Hg° interferes with physiological processes of the epiphytic lichen Evernia prunastri. ► Hg° promotes changes in the concentration of photosynthetic pigments. ► Hg° treatment causes changes in the ultrastructure of the photobiont plastids. ► Hg° induces changes in the protein machinery involved in the photosynthesis pathway. - Mercury affects the photosynthetic protein machinery of lichens.

  12. Estimating the mercury exposure dose in a population of migratory bird hunters in the St. Lawrence River region, Quebec, Canada

    International Nuclear Information System (INIS)

    Duchesne, J.-F.; Levesque, B.; Gauvin, Denis; Braune, Birgit; Gingras, Suzanne; Dewailly, E.

    2004-01-01

    St. Lawrence River hunters (Quebec, Canada) are exposed to the pollutants, especially mercury, that contaminate birds and fish. However, the health risks of this have remained unclear because of a lack of information about the hunters' duck, geese, and sportfish consumption habits. A nutritional survey was set up to characterize waterfowl and sportfish consumption in St. Lawrence River duck hunters and to estimate their daily exposure to mercury. During the winter of 2000, 512 hunters selected from the Canadian Wildlife Service database completed a self-administered questionnaire. Daily exposure to contaminants was measured using data from the Canadian Wildlife Service (waterfowl) and available data on St. Lawrence River sportfish. The annual average consumption was 7.5 meals of ducks and geese and 8.7 meals of sportfish. The daily exposure to mercury related to waterfowl consumption was below the Canadian tolerable daily intake (TDI) of 0.47 μg/kg body wt/day for all participants. The daily mercury intake associated with fish consumption was greater than the TDI in 2 duck hunters. The daily exposure to mercury was higher than the TDI in 4 participants when both waterfowl and fish consumption were combined. Our results suggest that fish consumption (especially freshwater fish) represents the main source of exposure to pollutants in duck hunters

  13. An Investigation of Modifying Effects of Metallothionein Single-Nucleotide Polymorphisms on the Association between Mercury Exposure and Biomarker Levels

    Science.gov (United States)

    Wang, Yi; Goodrich, Jaclyn M.; Gillespie, Brenda; Werner, Robert; Basu, Niladri

    2012-01-01

    Background: Recent studies have suggested that several genes that mediate mercury metabolism are polymorphic in humans. Objective: We hypothesized that single-nucleotide polymorphisms (SNPs) in metallothionein (MT) genes may underlie interindividual differences in mercury biomarker levels. We studied the potential modifying effects of MT SNPs on mercury exposure–biomarker relationships. Methods: We measured total mercury in urine and hair samples of 515 dental professionals. We also surveyed occupational and personal exposures to dental amalgam and dietary fish consumption, from which daily methylmercury (MeHg) intake was estimated. Log-transformed urine and hair levels were modeled in multivariable linear regression separately against respective exposure surrogates, and the effect modification of 13 MT SNPs on exposure was investigated. Results: The mean mercury levels in urine (1.06 μg/L) and hair (0.51 μg/g) were not significantly different from the U.S. general population (0.95 μg/L and 0.47 μg/g, respectively). The mean estimated daily MeHg intake was 0.084 μg/kg/day (range, 0–0.98 μg/kg/day), with 25% of study population intakes exceeding the current U.S. Environmental Protection Agency reference dose of 0.1 μg/kg/day. Multivariate regression analysis showed that subjects with the MT1M (rs2270837) AA genotype (n = 10) or the MT2A (rs10636) CC genotype (n = 42) had lower urinary mercury levels than did those with the MT1M or MT2A GG genotype (n = 329 and 251, respectively) after controlling for exposure and potential confounders. After controlling for MeHg intake, subjects with MT1A (rs8052394) GA and GG genotypes (n = 24) or the MT1M (rs9936741) TT genotype (n = 459) had lower hair mercury levels than did subjects with MT1A AA (n = 113) or MT1M TC and CC genotypes (n = 15), respectively. Conclusion: Our findings suggest that some MT genetic polymorphisms may influence mercury biomarker concentrations at levels of exposure relevant to the general

  14. Contrasting Effects of Dissolved Organic Matter on Mercury Methylation by Geobacter sulfurreducens PCA and Desulfovibrio desulfuricans ND132.

    Science.gov (United States)

    Zhao, Linduo; Chen, Hongmei; Lu, Xia; Lin, Hui; Christensen, Geoff A; Pierce, Eric M; Gu, Baohua

    2017-09-19

    Natural dissolved organic matter (DOM) affects mercury (Hg) redox reactions and anaerobic microbial methylation in the environment. Several studies have shown that DOM can enhance Hg methylation, especially under sulfidic conditions, whereas others show that DOM inhibits Hg methylation due to strong Hg-DOM complexation. In this study, we investigated and compared the effects of DOM on Hg methylation by an iron-reducing bacterium Geobacter sulfurreducens PCA and a sulfate-reducing bacterium Desulfovibrio desulfuricans ND132 under nonsulfidic conditions. The methylation experiment was performed with washed cells either in the absence or presence of DOM or glutathione, both of which form strong complexes with Hg via thiol-functional groups. DOM was found to greatly inhibit Hg methylation by G. Sulfurreducens PCA but enhance Hg methylation by D. desulfuricans ND132 cells with increasing DOM concentration. These strain-dependent opposing effects of DOM were also observed with glutathione, suggesting that thiols in DOM likely played an essential role in affecting microbial Hg uptake and methylation. Additionally, DOM and glutathione greatly decreased Hg sorption by G. sulfurreducens PCA but showed little effect on D. desulfuricans ND132 cells, demonstrating that ND132 has a higher affinity to sorb or take up Hg than the PCA strain. These observations indicate that DOM effects on Hg methylation are bacterial strain specific, depend on the DOM:Hg ratio or site-specific conditions, and may thus offer new insights into the role of DOM in methylmercury production in the environment.

  15. Synergism between exposure to mercury and use of iodine supplements on thyroid hormones in pregnant women

    International Nuclear Information System (INIS)

    Llop, Sabrina; Lopez-Espinosa, Maria-Jose; Murcia, Mario; Alvarez-Pedrerol, Mar; Vioque, Jesús; Aguinagalde, Xabier; Julvez, Jordi

    2015-01-01

    Objective: To evaluate the association between mercury exposure and thyroid-stimulating hormone (TSH), total triiodothyronine (TT3) and free thyroxine (FT4) levels during pregnancy as well as to explore if there is any synergic action between mercury and intake of iodine from different sources. Methods: The study population was 1407 pregnant women participating in the Spanish INMA birth cohort study. Total mercury concentrations were analyzed in cord blood. Thyroid hormones (THs) were measured in serum samples collected at 13.2±1.5 weeks of gestation. The association between mercury and TH levels was evaluated with multivariate linear regression models. Effect modification caused by iodine intake from supplements and diet was also evaluated. Results: The geometric means of TSH, TT3, FT4 and mercury were 1.1 μU/L, 2.4 nmol/L, 10.5 pmol/L and 7.7 μg/L, respectively. Mercury levels were marginally significantly associated with TT3 (β: −0.05; 95%CI: −0.10, 0.01), but were neither associated with TSH nor FT4. The inverse association between mercury and TT3 levels was stronger among the iodine supplement consumers (−0.08; 95%CI: −0.15, −0.02, interaction p-value=0.07). The association with FT4 followed the same pattern, albeit not significant. Conclusion: Prenatal mercury exposure was inversely associated with TT3 levels among women who took iodine supplements during pregnancy. These results could be of public health concern, although further research is needed. - Highlights: • We studied the relationship between mercury and thyroid hormones among pregnant. • Mercury was marginally significantly associated with TT3, but not with TSH or FT4. • This association was stronger among the iodine supplement. • These results could be of public health concern, but further research is needed

  16. Synergism between exposure to mercury and use of iodine supplements on thyroid hormones in pregnant women

    Energy Technology Data Exchange (ETDEWEB)

    Llop, Sabrina, E-mail: llop_sab@gva.es [FISABIO–Universitat de València–Universitat Jaume I Joint Research Unit of Epidemiology and Environmental Health, Av. Catalunya 21, 46020 Valencia (Spain); Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Lopez-Espinosa, Maria-Jose; Murcia, Mario [FISABIO–Universitat de València–Universitat Jaume I Joint Research Unit of Epidemiology and Environmental Health, Av. Catalunya 21, 46020 Valencia (Spain); Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Alvarez-Pedrerol, Mar [Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Centre for Research in Environmental Epidemiology (CREAL), Doctor Aiguader 88, 08003 Barcelona (Spain); Municipal Institute of Medical Research (IMIM-Hospital del Mar), Doctor Aiguader 88, 08003 Barcelona (Spain); Vioque, Jesús [Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Universidad Miguel Hernandez, Avenida de Alicante KM 87, 03550 Sant Joan d´Alacant (Spain); Aguinagalde, Xabier [Laboratorio de Salud Pública de Alava, Santiago 11, 01002 Vitoria Gasteiz (Spain); Julvez, Jordi [Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid (Spain); Centre for Research in Environmental Epidemiology (CREAL), Doctor Aiguader 88, 08003 Barcelona (Spain); Municipal Institute of Medical Research (IMIM-Hospital del Mar), Doctor Aiguader 88, 08003 Barcelona (Spain); and others

    2015-04-15

    Objective: To evaluate the association between mercury exposure and thyroid-stimulating hormone (TSH), total triiodothyronine (TT3) and free thyroxine (FT4) levels during pregnancy as well as to explore if there is any synergic action between mercury and intake of iodine from different sources. Methods: The study population was 1407 pregnant women participating in the Spanish INMA birth cohort study. Total mercury concentrations were analyzed in cord blood. Thyroid hormones (THs) were measured in serum samples collected at 13.2±1.5 weeks of gestation. The association between mercury and TH levels was evaluated with multivariate linear regression models. Effect modification caused by iodine intake from supplements and diet was also evaluated. Results: The geometric means of TSH, TT3, FT4 and mercury were 1.1 μU/L, 2.4 nmol/L, 10.5 pmol/L and 7.7 μg/L, respectively. Mercury levels were marginally significantly associated with TT3 (β: −0.05; 95%CI: −0.10, 0.01), but were neither associated with TSH nor FT4. The inverse association between mercury and TT3 levels was stronger among the iodine supplement consumers (−0.08; 95%CI: −0.15, −0.02, interaction p-value=0.07). The association with FT4 followed the same pattern, albeit not significant. Conclusion: Prenatal mercury exposure was inversely associated with TT3 levels among women who took iodine supplements during pregnancy. These results could be of public health concern, although further research is needed. - Highlights: • We studied the relationship between mercury and thyroid hormones among pregnant. • Mercury was marginally significantly associated with TT3, but not with TSH or FT4. • This association was stronger among the iodine supplement. • These results could be of public health concern, but further research is needed.

  17. Mercury exposure in Munduruku Indians from the community of Sai Cinza, state of Para, Brazil

    International Nuclear Information System (INIS)

    Oliveira Santos, Elisabeth C. de; Maura de Jesus, Iracina; Camara, Volney e M.; Brabo, Edilson; Brito Loureiro, Edvaldo C.; Mascarenhas, Artur; Weirich, Judith; Ragio Luiz, Ronir; Cleary, David

    2002-01-01

    The objective of this cross-sectional study was to evaluate mercury exposure and health status among Munduruku Indians from the community of Sai inza, State of Para, Brazil. The population studied included 330 Indians, who submitted to a questionnaire, clinical exams, and collection of hair, blood, urine, and feces. Mercury was measured in hair and fish. Although no person was found to have overt mercury intoxication, the mean levels of mercury in hair were elevated (14.45 μg/g for children from 7 to 12 years ld, 15.70 μg/g for women between 14 and 44 years old, and 14.1 μg/g or the remaining population). Mercury levels in fish were below levels recommended by the World Health Organization, but rates of fish consumption ere high. These results place this indigenous population as a group under risk of mercury toxicity from the gold production

  18. Oral bioaccessibility and human exposure to anthropogenic and geogenic mercury in urban, industrial and mining areas

    NARCIS (Netherlands)

    Rodrigues, S.M.; Coelho, C.; Cruz, N.; Monteiro, R.J.R.; Henriques, B.; Duarte, A.C.; Romkens, P.F.A.M.; Pereira, E.

    2014-01-01

    The objective of this study was to characterize the link between bioaccessibility and fractionation of mercury (Hg) in soils and to provide insight into human exposure to Hg due to inhalation of airborne soil particles and hand-to-mouth ingestion of Hg-bearing soil. Mercury in soils from mining,

  19. Mercury adsorption to gold nanoparticle and thin film surfaces

    Science.gov (United States)

    Morris, Todd Ashley

    Mercury adsorption to gold nanoparticle and thin film surfaces was monitored by spectroscopic techniques. Adsorption of elemental mercury to colloidal gold nanoparticles causes a color change from wine-red to orange that was quantified by UV-Vis absorption spectroscopy. The wavelength of the surface plasmon mode of 5, 12, and 31 nm gold particles blue-shifts 17, 14, and 7.5 nm, respectively, after a saturation exposure of mercury vapor. Colorimetric detection of inorganic mercury was demonstrated by employing 2.5 nm gold nanoparticles. The addition of low microgram quantities of Hg 2+ to these nanoparticles induces a color change from yellow to peach or blue. It is postulated that Hg2+ is reduced to elemental mercury by SCN- before and/or during adsorption to the nanoparticle surface. It has been demonstrated that surface plasmon resonance spectroscopy (SPRS) is sensitive to mercury adsorption to gold and silver surfaces. By monitoring the maximum change in reflectivity as a function of amount of mercury adsorbed to the surface, 50 nm Ag films were shown to be 2--3 times more sensitive than 50 nm Au films and bimetallic 15 nm Au/35 nm Ag films. In addition, a surface coverage of ˜40 ng Hg/cm2 on the gold surface results in a 0.03° decrease in the SPR angle of minimum reflectivity. SPRS was employed to follow Hg exposure to self-assembled monolayers (SAMs) on Au. The data indicate that the hydrophilic or hydrophobic character of the SAM has a significant effect on the efficiency of Hg penetration. Water adsorbed to carboxylic acid end group of the hydrophilic SAMs is believed to slow the penetration of Hg compared to methyl terminated SAMs. Finally, two protocols were followed to remove mercury from gold films: immersion in concentrated nitric acid and thermal annealing up to 200°C. The latter protocol is preferred because it removes all of the adsorbed mercury from the gold surface and does not affect the morphology of the gold surface.

  20. Efficacy of succimer chelation of mercury at background exposures in toddlers: a randomized trial

    Science.gov (United States)

    Cao, Yang; Chen, Aimin; Jones, Robert L.; Radcliffe, Jerilynn; Dietrich, Kim N.; Caldwell, Kathleen L.; Peddada, Shyamal; Rogan, Walter J.

    2011-01-01

    Objective To examine whether succimer, a mercaptan compound known to reduce blood lead concentration in children, reduces blood mercury concentration. Study Design We used samples from a randomized clinical trial of succimer chelation for lead-exposed children. We measured mercury in pre-treatment samples from 767 children. We also measured mercury in blood samples drawn 1 week after treatment began (N=768) and in a 20% random sample of the children who received the maximum 3 courses of treatment (N=67). A bootstrap-based isotonic regression method was used to compare the trend over time in the difference between the adjusted mean mercury concentrations in the succimer group and the placebo group. Results The adjusted mean organic mercury concentration in the succimer group relative to the placebo group fell from 99% at baseline to 82% after three courses of treatment (p for trend = 0.048), but this resulted from the prevention of the age-related increase in the succimer group. Conclusion Succimer chelation for low level organic mercury exposure in children has limited efficacy. PMID:20889164

  1. New Mechanisms of Mercury Binding to Peat

    Science.gov (United States)

    Nagy, K. L.; Manceau, A.; Gasper, J. D.; Ryan, J. N.; Aiken, G. R.

    2007-12-01

    Mercury can be immobilized in the aquatic environment by binding to peat, a solid form of natural organic matter. Binding mechanisms can vary in strength and reversibility, and therefore will control concentrations of bioreactive mercury, may explain rates of mercury methylation, and are important for designing approaches to improve water quality using natural wetlands or engineered phytoremediation schemes. In addition, strong binding between mercury and peat is likely to result in the fixation of mercury that ultimately resides in coal. The mechanisms by which aqueous mercury at low concentrations reacts with both dissolved and solid natural organic matter remain incompletely understood, despite recent efforts. We have identified three distinct binding mechanisms of divalent cationic mercury to solid peats from the Florida Everglades using EXAFS spectroscopic data (FAME beamline, European Synchrotron Radiation Facility (ESRF)) obtained on experimental samples as compared to relevant references including mercury-bearing solids and mercury bound to various organic molecules. The proportions of the three molecular configurations vary with Hg concentration, and two new configurations that involve sulfur ligands occur at Hg concentrations up to about 4000 ppm. The binding mechanism at the lowest experimental Hg concentration (60-80 ppm) elucidates published reports on the inhibition of metacinnabar formation in the presence of Hg-bearing solutions and dissolved natural organic matter, and also, the differences in extent of mercury methylation in distinct areas of the Florida Everglades.

  2. Prenatal exposure to methyl mercury from fish consumption and polyunsaturated fatty acids: associations with child development at 20 mo of age in an observational study in the Republic of Seychelles.

    Science.gov (United States)

    Strain, J J; Yeates, Alison J; van Wijngaarden, Edwin; Thurston, Sally W; Mulhern, Maria S; McSorley, Emeir M; Watson, Gene E; Love, Tanzy M; Smith, Tristram H; Yost, Kelley; Harrington, Donald; Shamlaye, Conrad F; Henderson, Juliette; Myers, Gary J; Davidson, Philip W

    2015-03-01

    Fish is a rich source of n-3 polyunsaturated fatty acids (PUFAs) but also contains the neurotoxicant methyl mercury (MeHg). PUFAs may modify the relation between prenatal MeHg exposure and child development either directly by enhancing neurodevelopment or indirectly through the inflammatory milieu. The objective was to investigate the associations of prenatal MeHg exposure and maternal PUFA status with child development at 20 mo of age. The Seychelles Child Development Study Nutrition Cohort 2 is an observational study in the Republic of Seychelles, a high-fish-eating population. Mothers were enrolled during pregnancy and their children evaluated at 20 mo of age by using the Bayley Scales of Infant Development II (BSID-II), the MacArthur Bates Communicative Development Inventories (CDI), and the Infant Behavior Questionnaire-Revised. There were 1265 mother-child pairs with complete data. Prenatal MeHg exposure had no direct associations with neurodevelopmental outcomes. Significant interactions were found between MeHg and PUFAs on the Psychomotor Developmental Index (PDI) of the BSID-II. Increasing MeHg was associated with lower PDI but only in children of mothers with higher n-6/n-3. Among mothers with higher n-3 PUFAs, increasing MeHg was associated with improved PDI. Higher maternal docosahexaenoic acid (DHA) was associated with improved CDI total gestures (language development) but was significantly adversely associated with the Mental Development Index (MDI), both with and without MeHg adjustment. Higher n-6:n-3 ratios were associated with poorer scores on all 3 CDI outcomes. We found no overall adverse association between prenatal MeHg exposure and neurodevelopmental outcomes. However, maternal PUFA status as a putative marker of the inflammatory milieu appeared to modify the associations of prenatal MeHg exposure with the PDI. Increasing DHA status was positively associated with language development yet negatively associated with the MDI. These findings may

  3. Mercury reduces avian reproductive success and imposes selection: an experimental study with adult- or lifetime-exposure in zebra finch.

    Directory of Open Access Journals (Sweden)

    Claire W Varian-Ramos

    Full Text Available Mercury is a global pollutant that biomagnifies in food webs, placing wildlife at risk of reduced reproductive fitness and survival. Songbirds are the most diverse branch of the avian evolutionary tree; many are suffering persistent and serious population declines and we know that songbirds are frequently exposed to mercury pollution. Our objective was to determine the effects of environmentally relevant doses of mercury on reproductive success of songbirds exposed throughout their lives or only as adults. The two modes of exposure simulated philopatric species versus dispersive species, and are particularly relevant because of the heightened mercury-sensitivity of developing nervous systems. We performed a dosing study with dietary methylmercury in a model songbird species, the zebra finch (Taeniopygia guttata, at doses from 0.3 - 2.4 parts per million. Birds were exposed to mercury either as adults only or throughout their lives. All doses of mercury reduced reproductive success, with the lowest dose reducing the number of independent offspring produced in one year by 16% and the highest dose, representing approximately half the lethal dose for this species, causing a 50% reduction. While mercury did not affect clutch size or survivorship, it had the most consistent effect on the proportion of chicks that fledged from the nest, regardless of mode of exposure. Among birds exposed as adults, mercury caused a steep increase in the latency to re-nest after loss of a clutch. Birds exposed for their entire lifetimes, which were necessarily the offspring of dosed parents, had up to 50% lower reproductive success than adult-exposed birds at low doses of methylmercury, but increased reproductive success at high doses, suggesting selection for mercury tolerance at the highest level of exposure. Our results indicate that mercury levels in prey items at contaminated sites pose a significant threat to populations of songbirds through reduced reproductive

  4. Mercury Reduces Avian Reproductive Success and Imposes Selection: An Experimental Study with Adult- or Lifetime-Exposure in Zebra Finch

    Science.gov (United States)

    Varian-Ramos, Claire W.; Swaddle, John P.; Cristol, Daniel A.

    2014-01-01

    Mercury is a global pollutant that biomagnifies in food webs, placing wildlife at risk of reduced reproductive fitness and survival. Songbirds are the most diverse branch of the avian evolutionary tree; many are suffering persistent and serious population declines and we know that songbirds are frequently exposed to mercury pollution. Our objective was to determine the effects of environmentally relevant doses of mercury on reproductive success of songbirds exposed throughout their lives or only as adults. The two modes of exposure simulated philopatric species versus dispersive species, and are particularly relevant because of the heightened mercury-sensitivity of developing nervous systems. We performed a dosing study with dietary methylmercury in a model songbird species, the zebra finch (Taeniopygia guttata), at doses from 0.3 – 2.4 parts per million. Birds were exposed to mercury either as adults only or throughout their lives. All doses of mercury reduced reproductive success, with the lowest dose reducing the number of independent offspring produced in one year by 16% and the highest dose, representing approximately half the lethal dose for this species, causing a 50% reduction. While mercury did not affect clutch size or survivorship, it had the most consistent effect on the proportion of chicks that fledged from the nest, regardless of mode of exposure. Among birds exposed as adults, mercury caused a steep increase in the latency to re-nest after loss of a clutch. Birds exposed for their entire lifetimes, which were necessarily the offspring of dosed parents, had up to 50% lower reproductive success than adult-exposed birds at low doses of methylmercury, but increased reproductive success at high doses, suggesting selection for mercury tolerance at the highest level of exposure. Our results indicate that mercury levels in prey items at contaminated sites pose a significant threat to populations of songbirds through reduced reproductive success. PMID

  5. Fish consumption limit for mercury compounds

    Directory of Open Access Journals (Sweden)

    Abbas Esmaili-Sari

    2011-09-01

    Full Text Available Background and objectives: Methyl mercury can carry out harmful effects on the reproductive, respiratory, and nervous system of human. Moreover, mercury is known as the most toxic heavy metal in nature. Fish and seafood consumption is the major MeHg exposure route for human. The present study tries to cover researches which have been conducted on mercury levels in 21 species of fish from Persian Gulf, Caspian Sea and Anzali Wetland during the past 6 years, and in addition to stating mercury level, it provides recommendations about the restriction of monthly fish consumption for each species separately. Material and methods: Fish samples were transferred to the laboratory and stored in refrigerator under -20oC until they were dissected. Afterwards, the muscle tissues were separated and dried. The dried samples were ground and changed into a homogenous powder and then the mercury concentration rate has been determined by advanced mercury analyzer, model 254. Results: In general, mercury contamination in fishes caught from Anzali Wetland was much more than fishes from Caspian Sea. Also, from among all studied fishes, oriental sole (Euryglossa orientalis, caught from Persian Gulf, allocated the most mercury level to itself with the rate of 5.61ml per kg., therefore, it exercises a severe consumption restriction for pregnant women and vulnerable groups. Conclusion: Based on the calculations, about 50% of fishes, mostly with short food chain, can be easily consumed during the year. However, with regard to Oriental sole (Euryglossa orientalis and shark (Carcharhinus dussumieri, caught from Persian Gulf, special consideration should be taken in their consumption. On the other hand, careful planning should be made for the high rate of fish consumption among fishing community.

  6. Exposure to methyl bromide during greenhouse fumigation on Crete, Greece

    NARCIS (Netherlands)

    Vreede, J.A.F. de; Boeft, J. den; Hemmen, J.J. van

    1998-01-01

    In agricultural areas where greenhouses and dwellings are intermixed, the general population as well as the professional applicators may be exposed to pesticides. In a field study on Crete, exposure to methyl bromide during soil fumigation was assessed. Exposure of applicators (both contractors and

  7. Global Mercury Pathways in the Arctic Ecosystem

    Science.gov (United States)

    Lahoutifard, N.; Lean, D.

    2003-12-01

    The sudden depletions of atmospheric mercury which occur during the Arctic spring are believed to involve oxidation of gaseous elemental mercury, Hg(0), rendering it less volatile and more soluble. The Hg(II) oxidation product(s) are more susceptible to deposition, consistent with the observation of dramatic increases in snow mercury levels during depletion events. Temporal correlations with ozone depletion events and the proliferation of BrO radicals support the hypothesis that oxidation of Hg(0) occurs in the gas phase and results in its conversion to RGM (Reactive Gaseous Mercury). The mechanisms of Hg(0) oxidation and particularly Hg(II) reduction are as yet unproven. In order to evaluate the feasibility of proposed chemical processes involving mercury in the Arctic atmosphere and its pathway after deposition on the snow from the air, we investigated mercury speciation in air and snow pack at Resolute, Nunavut, Canada (latitude 75° N) prior to and during snow melt during spring 2003. Quantitative, real-time information on emission, air transport and deposition were combined with experimental studies of the distribution and concentrations of different mercury species, methyl mercury, anions, total organic carbon and total inorganic carbon in snow samples. The effect of solar radiation and photoreductants on mercury in snow samples was also investigated. In this work, we quantify mercury removed from the air, and deposited on the snow and the transformation to inorganic and methyl mercury.

  8. Methyl mercury bioaccumulation in long-finned eels, Anguilla dieffenbachii, from three rivers in Otago, New Zealand.

    Science.gov (United States)

    Redmayne, A C; Kim, J P; Closs, G P; Hunter, K A

    2000-10-30

    This research focuses on mercury (Hg) bioaccumulation in New Zealand long-tinned eels (Anguilla dieffenbachii) from the aquatic environment. Total Hg (HgT) and methyl mercury (MeHg) concentrations were determined in muscle tissue from eels living in three South Island rivers dominated respectively by urban, native bush and agricultural land-uses. Most of the Hg in eels was MeHg (> 84%) and the MeHg concentrations increased linearly with both length and eel age for a given river habitat. The annual growth rates for eels from the urban and agricultural streams were greater than for eels from the native bush stream. The average MeHg accumulation rate was significantly higher for the eels in the agricultural stream compared with either the urban or native bush catchments. These results are probably due to a combination of factors and further investigations in the lower food web are necessary to elucidate the exact mechanisms of MeHg bioaccumulation in these creatures.

  9. Mercury species in lymphoid and non-lymphoid tissues after exposure to methyl mercury: Correlation with autoimmune parameters during and after treatment in susceptible mice

    International Nuclear Information System (INIS)

    Havarinasab, Said; Bjoern, Erik; Nielsen, Jesper B.; Hultman, Per

    2007-01-01

    Methylmercury (MeHg) is present in the environment as a result of the global cycling of mercury, although anthropogenic sources may dramatically increase the availability in confined geographical areas. Accumulation of MeHg in the aquatic food chain is the dominating way of exposure in mammals, which accumulate MeHg in all organs, including Brain. Demethylation has been described in the organs, especially in phagocytic cells, but mainly in the flora of the intestinal tract. While most of the inorganic mercury (Hg 2+ ) formed in the intestine is excreted, a fraction is reabsorbed which together with the local demethylation increases the organ Hg 2+ concentration. MeHg is a well-known immunosuppressive agent, while Hg 2+ is associated with immunostimulation and autoimmunity especially in genetically susceptible rodents, creating a syndrome, i.e. mercury-induced autoimmunity (HgIA). This study aimed at exploring the effect of MeHg with regard to HgIA, and especially the immunological events after stopping treatment, correlated with the presence of MeHg and Hg 2+ in the organs. Treatment of A.SW mice for 30 days with 4.2 mg MeHg/L drinking water (corresponding to approximately 420 μg Hg/kg body weight/day) caused all the HgIA features observed after primary treatment with inorganic Hg, except systemic immune complex deposits. The total Hg concentration was 5-fold higher in the kidneys as compared with lymph nodes, but the fraction of Hg 2+ was similar (17-20%). After stopping treatment, the renal and lymph node MeHg concentration declined according to first order kinetics during the initial 4-6 weeks, but then slower. A similar decline in the organ Hg 2+ concentration occurred during the initial 2 weeks after stopping treatment but then ceased, causing the Hg 2+ concentration to exceed that of MeHg in the lymph nodes and kidneys after 3 and 8 weeks, respectively. The selective increase in lymph node Hg 2+ fraction is likely to be due to demethylation of MeHg in the

  10. Estimating threshold limits for mercury in biological material

    Energy Technology Data Exchange (ETDEWEB)

    Berlin, M H

    1963-01-01

    A brief historical review of the study of occupational exposure to mercury is presented. Important factors in the determination of the tolerable body burden of mercury are discussed, notably the body distribution of mercury after exposure, and the risk of accumulation in different organs. In acute exposure the kidney and liver accumulate much mercury and are hence liable to injury, while recent findings indicate that in chronic exposure to moderate levels of mercury the brain and possibly testes are the critical organs because of a pronounced tendency to accumulate. The possibility of obtaining an index of mercury retention is explored; it is concluded that urinary mercury excretion does not reflect the level of body retention although it may indicate very recent exposure. It is suggested that mercury concentration in biopsies of skin, liver, kidney and colonic mucosa may serve as an index of body retention of mercury. 37 references, 7 figures.

  11. Mercury exposure in Ireland

    DEFF Research Database (Denmark)

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

    2014-01-01

    of a study to Coordinate and Perform Human Biomonitoring on a European Scale (DEMOCOPHES) pilot biomonitoring study. METHODS: Hair mercury concentrations were determined from a convenience sample of 120 mother/child pairs. Mothers also completed a questionnaire. Rigorous quality assurance within DEMOCOPHES...... guaranteed the accuracy and international comparability of results. RESULTS: Mercury was detected in 79.2% of the samples from mothers, and 62.5% of children's samples. Arithmetic mean levels in mothers (0.262 µg/g hair) and children (0.149 µg /g hair) did not exceed the US EPA guidance value. Levels were...

  12. Environmental Mercury and Its Toxic Effects

    Directory of Open Access Journals (Sweden)

    Kevin M. Rice

    2014-03-01

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

  13. Mercury contaminated sediment sites—An evaluation of remedial options

    Energy Technology Data Exchange (ETDEWEB)

    Randall, Paul M., E-mail: randall.paul@epa.gov [U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States); Chattopadhyay, Sandip, E-mail: Sandip.Chattopadhyay@tetratech.com [Tetra Tech, Inc., 250 West Court Street, Suite 200W, Cincinnati, OH 45202 (United States)

    2013-08-15

    Mercury (Hg) is a naturally-occurring element that is ubiquitous in the aquatic environment. Though efforts have been made in recent years to decrease Hg emissions, historically-emitted Hg can be retained in the sediments of aquatic bodies where they may be slowly converted to methylmercury (MeHg). Consequently, Hg in historically-contaminated sediments can result in high levels of significant exposure for aquatic species, wildlife and human populations consuming fish. Even if source control of contaminated wastewater is achievable, it may take a very long time, perhaps decades, for Hg-contaminated aquatic systems to reach relatively safe Hg levels in both water and surface sediment naturally. It may take even longer if Hg is present at higher concentration levels in deep sediment. Hg contaminated sediment results from previous releases or ongoing contributions from sources that are difficult to identify. Due to human activities or physical, chemical, or biological processes (e.g. hydrodynamic flows, bioturbation, molecular diffusion, and chemical transformation), the buried Hg can be remobilized into the overlying water. Hg speciation in the water column and sediments critically affect the reactivity (i.e. conversion of inorganic Hg(II) to MeHg), transport, and its exposure to living organisms. Also, geochemical conditions affect the activity of methylating bacteria and its availability for methylation. This review paper discusses remedial considerations (e.g. key chemical factors in fate and transport of Hg, source characterization and control, environmental management procedures, remediation options, modeling tools) and includes practical case studies for cleaning up Hg-contaminated sediment sites. -- Highlights: ► Managing mercury-contaminated sediment sites are challenging to remediate. ► Remediation technologies are making a difference in managing these sites. ► Partitioning plays a dominant role in the distribution of mercury species. ► Mathematical

  14. Fish Consumption and Mercury Exposure among Louisiana Recreational Anglers

    DEFF Research Database (Denmark)

    Lincoln, Rebecca A; Shine, James P; Chesney, Edward J

    2011-01-01

    Background: Methylmercury (MeHg) exposure assessments among average fish consumers in the U.S. may underestimate exposures among U.S. subpopulations with high intakes of regionally specific fish. Objectives: We examined relationships between fish consumption, estimated mercury (Hg) intake......, and measured Hg exposure among one such potentially highly-exposed group, recreational anglers in Louisiana USA. Methods: We surveyed 534 anglers in 2006 using interviews at boat launches and fishing tournaments combined with an internet-based survey method. Hair samples from 402 of these anglers were...... collected and analyzed for total Hg. Questionnaires provided information on species-specific fish consumption over 3 months prior to the survey. Results: Anglers' median hair-Hg concentration was 0.81 µg/g (n=398; range: 0.02-10.7 µg/g), with 40% of participants above 1 µg/g, the level that approximately...

  15. Hair Mercury Levels in Six Iranian Sub-populations for Estimation of Methylmercury Exposure: A Mini-review

    Directory of Open Access Journals (Sweden)

    Abbas Esmaili-Sari

    2012-01-01

    Full Text Available Background: Mercury is widespread and persistent in the environment. One organicform of mercury, Methylmercury (MeHg, can accumulate in the food chain in aquaticecosystems and lead to high concentrations of MeHg in fish, which, when consumed byhumans, can result in an increased risk of adverse effects. Currently, the Joint FAO/WHOExpert Committee on Food Additives (JECFA has established provisional tolerableweekly intakes (PTWIs for total mercury at 5 μg/kg body weight and for methylmercury at1.6 μg/kg body weight. Mercury concentration in blood or hair has been widely used forestimation of methylmercury exposure.Materials and Methods: In this review article, we calculated methylmercury exposurefrom hair mercury levels among six subpopulations (i.e. students, dentists, dental nurses,women with amalgam fillings, pregnant women in Mahshahr, and Women of a port town,Mahshahr, Iran. Some of the experiments had been performed by this group in previousyears.Results: The mean exposure level (μg/kg bw/day in three Iranian groups (dentists,pregnant women, and women in Mahshahr was higher than RfD and PTWIs.Conclusion: As people are exposed to methylmercury mainly through their diet,especially from fish and other marine species, pregnant women should reduce fishconsumption, especially predatory fish, and dentists should use preventive measures (likemasks and gloves.

  16. Distribution and excretion of inhaled mercury vapour

    Energy Technology Data Exchange (ETDEWEB)

    Gage, J C

    1961-01-01

    Rats have been exposed for varying periods to an atmosphere containing 1 mg/cu.m. mercury vapor. The toxic effects produced showed resemblances to signs of mercurialism in man. An attempt has been made to study the kinetics of absorption and excretion of mercury from measurements of the amounts excreted and stored in the tissues. The efficiency of absorption of mercury by the rat lung is about 50%. A small proportion is excreted into the gut. After about 10 days of continuous exposure a steady state is reached in which excretion balances absorption. During short exposures the turnover of mercury in all tissues except brain is fairly rapid and most of the mercury is cleared from the body within a week after exposure. The urinary excretion of mercury, during the initial stage of storage in the tissues and the final stage of clearance, shows divergencies from the simple exponential pattern; there appears to be a delay mechanism in the kidney which, in intermittent exposures, may result in the occurrence of peak excretion during periods of non-exposure. After more prolonged exposures the mercury in the kidney appears to be converted to a form which is only very slowly excreted. The significance of the urinary excretion of mercury by man after industrial exposure to mercury vapour is discussed. The rat experiments suggest that single measurements will give only limited information concerning industrial conditions, but that an approximate assessment of the total absorbed during a working week would be obtained if it were possible to make a seven-day collection of urine. Repeated measurements after exposure would yield information on the duration of exposure and would have some diagnostic value.

  17. Mercury methylation and demethylation by periphyton biofilms and their host in a fluvial wetland of the St. Lawrence River (QC, Canada)

    International Nuclear Information System (INIS)

    Hamelin, Stéphanie; Planas, Dolors; Amyot, Marc

    2015-01-01

    Wetlands in large rivers are important sites of production of the neurotoxin methylmercury (MeHg), and the periphyton growing on wetland macrophytes are increasingly recognized as key players in this production and transfer in food webs. Information is lacking about mercury methylation (K m ) and demethylation (K d ) rates in periphytic biofilms from the Northern Hemisphere, as well as about the drivers of net MeHg production, hampering ecosystem modeling of Hg cycling. Mercury methylation and demethylation rates were measured in periphytic biofilms growing on submerged plants in a shallow fluvial lake located in a temperate cold region (St. Lawrence River, Quebec, Canada). Incubations were performed in situ within macrophyte beds using low-level spikes of 199 HgO and Me 200 Hg stable isotopes as tracers. A direct relationship was observed between K m (0.002 to 0.137 d −1 ) and [MeHg] in periphyton. A similar relationship was found between K d (0.096 to 0.334 d −1 ) and [inorganic Hg]. Periphyton of Lake St. Pierre reached high levels of net MeHg production that were two orders of magnitude higher than those found in local sediment. This production varied through the plant growing season and was mainly driven by environmental variables such as depth of growth, available light, dissolved oxygen, temperature, plant community structure, and productivity of the habitat. - Highlights: • Periphyton Hg methylation and demethylation were studied in a large fluvial lake. • Addition of stable Hg isotopes was used to obtain in situ rates for these processes. • Net methylation was higher in periphyton than in local sediments. • Methylation and demethylation rates fluctuated during the summer. • Key drivers of rates were depth, light, temperature, and community structure

  18. Mercury methylation and demethylation by periphyton biofilms and their host in a fluvial wetland of the St. Lawrence River (QC, Canada)

    Energy Technology Data Exchange (ETDEWEB)

    Hamelin, Stéphanie; Planas, Dolors [GRIL, Département de sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal, Quebec H3C 3P8 (Canada); Amyot, Marc [GRIL, Département de sciences biologiques, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, Quebec H3C 3J7 (Canada)

    2015-04-15

    Wetlands in large rivers are important sites of production of the neurotoxin methylmercury (MeHg), and the periphyton growing on wetland macrophytes are increasingly recognized as key players in this production and transfer in food webs. Information is lacking about mercury methylation (K{sub m}) and demethylation (K{sub d}) rates in periphytic biofilms from the Northern Hemisphere, as well as about the drivers of net MeHg production, hampering ecosystem modeling of Hg cycling. Mercury methylation and demethylation rates were measured in periphytic biofilms growing on submerged plants in a shallow fluvial lake located in a temperate cold region (St. Lawrence River, Quebec, Canada). Incubations were performed in situ within macrophyte beds using low-level spikes of {sup 199}HgO and Me{sup 200}Hg stable isotopes as tracers. A direct relationship was observed between K{sub m} (0.002 to 0.137 d{sup −1}) and [MeHg] in periphyton. A similar relationship was found between K{sub d} (0.096 to 0.334 d{sup −1}) and [inorganic Hg]. Periphyton of Lake St. Pierre reached high levels of net MeHg production that were two orders of magnitude higher than those found in local sediment. This production varied through the plant growing season and was mainly driven by environmental variables such as depth of growth, available light, dissolved oxygen, temperature, plant community structure, and productivity of the habitat. - Highlights: • Periphyton Hg methylation and demethylation were studied in a large fluvial lake. • Addition of stable Hg isotopes was used to obtain in situ rates for these processes. • Net methylation was higher in periphyton than in local sediments. • Methylation and demethylation rates fluctuated during the summer. • Key drivers of rates were depth, light, temperature, and community structure.

  19. Spatial Patterns of Mercury Bioaccumulation in the Upper Clark Fork River Basin, MT

    Science.gov (United States)

    Staats, M. F.; Langner, H.; Moore, J. N.

    2010-12-01

    The Upper Clark Fork River Basin (UCFRB) in Montana has a legacy of historic gold/silver mine waste that contributes large quantities of mercury into the watershed. Mercury bioaccumulation at higher levels of the aquatic food chain, such as the mercury concentration in the blood of pre-fledge osprey, exhibit an irregular spatial signature based on the location of the nests throughout the river basin. Here we identify regions with a high concentration of bioavailable mercury and the major factors that allow the mercury to bioaccumulate within trophic levels. This identification is based on the abundance of mercury sources and the potential for mercury methylation. To address the source term, we did a survey of total mercury in fine sediments along selected UCFRB reaches, along with the assessment of environmental river conditions (percentage of backwaters/wetlands, water temperature and pH, etc). In addition, we analyzed the mercury levels of a representative number of macroinvertebrates and fish from key locations. The concentration of total mercury in sediment, which varies from reach to reach (tributaries of the Clark Fork River, 5mg/kg) affects the concentration of mercury found at various trophic levels. However, reaches with a low supply of mine waste-derived mercury can also yield substantial concentrations of mercury in the biota, due to highly favorable conditions for mercury methylation. We identify that the major environmental factor that affects the methylation potential in the UCFRB is the proximity and connectivity of wetland areas to the river.

  20. Current Mercury Exposure from Artisanal and Small-Scale Gold Mining in Bombana, Southeast Sulawesi, Indonesia-Future Significant Health Risks.

    Science.gov (United States)

    Sakakibara, Masayuki; Sera, Koichiro

    2017-02-08

    The rapid expansion of the artisanal and small-scale gold mining (ASGM) industry in developing countries has marginalized the local communities in poverty, and resulted in occupational exposure to mercury via the gold extraction process. We investigated the mercury exposure of the mining workers lived inside and outside the mining area. Based on the occupations of the contributors, the hair samples were divided into three subgroups: directly exposed, indirectly exposed, and a control. A total of 81 hair samples were analyzed by particle-induced X-ray emission spectrometry. The median mercury concentration was highest in the hair from the directly exposed group (12.82 μg/g hair) (control group median: 4.8 μg/g hair, p mining area but who are not engaged in mercury-based gold extraction.

  1. Mercury exposure, serum antinuclear/antinucleolar antibodies, and serum cytokine levels in mining populations in Amazonian Brazil: a cross-sectional study.

    Science.gov (United States)

    Gardner, Renee M; Nyland, Jennifer F; Silva, Ines A; Ventura, Ana Maria; de Souza, Jose Maria; Silbergeld, Ellen K

    2010-05-01

    Mercury is an immunotoxic substance that has been shown to induce autoimmune disease in rodent models, characterized by lymphoproliferation, overproduction of immunoglobulin (IgG and IgE), and high circulating levels of auto-antibodies directed at antigens located in the nucleus (antinuclear auto-antibodies, or ANA) or the nucleolus (antinucleolar auto-antibodies, or ANoA). We have reported elevated levels of ANA and ANoA in human populations exposed to mercury in artisanal gold mining, though other confounding variables that may also modulate ANA/ANoA levels were not well controlled. The goal of this study is to specifically test whether occupational and environmental conditions (other than mercury exposure) that are associated with artisanal gold mining affect the prevalence of markers of autoimmune dysfunction. We measured ANA, ANoA, and cytokine concentrations in serum and compared results from mercury-exposed artisanal gold miners to those from diamond and emerald miners working under similar conditions and with similar socio-economic status and risks of infectious disease. Mercury-exposed gold miners had higher prevalence of detectable ANA and ANoA and higher titers of ANA and ANoA as compared to diamond and emerald miners with no occupational mercury exposure. Also, mercury-exposed gold miners with detectable ANA or ANoA in serum had significantly higher concentrations of pro-inflammatory cytokines IL-1beta, TNF-alpha, and IFN-gamma in serum as compared to the diamond and emerald miners. This study provides further evidence that mercury exposure may lead to autoimmune dysfunction and systemic inflammation in affected populations. Copyright 2010 Elsevier Inc. All rights reserved.

  2. Benzopyrene exposure disrupts DNA methylation and growth dynamics in breast cancer cells

    International Nuclear Information System (INIS)

    Sadikovic, Bekim; Rodenhiser, David I.

    2006-01-01

    Exposures to environmental carcinogens and unhealthy lifestyle choices increase the incidence of breast cancer. One such compound, benzo(a)pyrene (BaP), leads to covalent DNA modifications and the deregulation of gene expression. To date, these mechanisms of BaP-induced carcinogenesis are poorly understood, particularly in the case of breast cancer. We tested the effects of BaP exposure on cellular growth dynamics and DNA methylation in four breast cancer cell lines since disruptions in DNA methylation lead to deregulated gene expression and the loss of genomic integrity. We observed robust time- and concentration-dependent loss of proliferation, S phase and G2M accumulation and apoptosis in p53 positive MCF-7 and T47-D cells. We observed minimal responses in p53 negative HCC-1086 and MDA MB 231 cells. Furthermore, BaP increased p53 levels in both p53 positive cell lines, as well as p21 levels in MCF-7 cells, an effect that was prevented by the p53-specific inhibitor pifithrin-α. No changes in global levels of DNA methylation levels induced by BaP were detected by the methyl acceptor assay (MAA) in any cell line, however, methylation profiling by AIMS (amplification of intermethylated sites) analysis showed dynamic, sequence-specific hypo- and hypermethylation events in all cell lines. We also identified BaP-induced hypomethylation events at a number of genomic repeats. Our data confirm the p53-specific disruption of the cell cycle as well as the disruption of DNA methylation as a consequence of BaP treatment, thus reinforcing the link between environmental exposures, DNA methylation and breast cancer

  3. Prenatal exposure to mercury and longitudinally assessed fetal growth: Relation and effect modifiers.

    Science.gov (United States)

    Ballester, Ferran; Iñiguez, Carmen; Murcia, Mario; Guxens, Mònica; Basterretxea, Mikel; Rebagliato, Marisa; Vioque, Jesús; Lertxundi, Aitana; Fernandez-Somoano, Ana; Tardon, Adonina; Sunyer, Jordi; Llop, Sabrina

    2018-01-01

    Prenatal mercury exposure has been related to reductions in anthropometry at birth. Levels of mercury have been reported as being relatively elevated in the Spanish population. To investigate the relation between prenatal exposure to mercury and fetal growth. Study subjects were pregnant women and their newborns (n:1867) participating in a population-based birth cohort study set up in four Spanish regions from the INMA Project. Biparietal diameter (BPD), femur length (FL), abdominal circumference (AC), and estimated fetal weight (EFW) were measured by ultrasounds at 12, 20, and 34 weeks of gestation. Size at and growth between these points were assessed by standard deviation (SD) scores adjusted for constitutional characteristics. Total mercury (T-Hg) was determined in cord blood. Associations were investigated by linear regression models, adjusted by sociodemographic, environmental, nutritional - including four seafood groups - and lifestyle-related variables in each sub-cohort. Final estimates were obtained using meta-analysis. Effect modification by sex, seafood intake and polychlorinated biphenyl (PCB) congener 153 concentration was assessed. Geometric mean of cord blood T-Hg was 8.2μg/L. All the estimates of the association between prenatal Hg and growth from 0 to 12 weeks showed reductions in SD-scores, which were only statistically significant for BPD. A doubling of cord blood T-Hg was associated with a 0.58% reduction in size of BPD at week 12 (95% confidence interval -CI-: - 1.10, - 0.07). Size at week 34 showed estimates suggestive of a small reduction in EFW, i.e., a doubling of T-Hg levels was associated with a reduction of 0.38% (95% CI: - 0.91, 0.15). An interaction between PCB153 and T-Hg was found, with statistically significant negative associations of T-Hg with AC and EFW in late pregnancy among participants with PCB153 below the median. Exposure to mercury during pregnancy was associated with early reductions in BPD. Moreover, an antagonism with

  4. Technical report: mercury in the environment: implications for pediatricians.

    Science.gov (United States)

    Goldman, L R; Shannon, M W

    2001-07-01

    Mercury is a ubiquitous environmental toxin that causes a wide range of adverse health effects in humans. Three forms of mercury (elemental, inorganic, and organic) exist, and each has its own profile of toxicity. Exposure to mercury typically occurs by inhalation or ingestion. Readily absorbed after its inhalation, mercury can be an indoor air pollutant, for example, after spills of elemental mercury in the home; however, industry emissions with resulting ambient air pollution remain the most important source of inhaled mercury. Because fresh-water and ocean fish may contain large amounts of mercury, children and pregnant women can have significant exposure if they consume excessive amounts of fish. The developing fetus and young children are thought to be disproportionately affected by mercury exposure, because many aspects of development, particularly brain maturation, can be disturbed by the presence of mercury. Minimizing mercury exposure is, therefore, essential to optimal child health. This review provides pediatricians with current information on mercury, including environmental sources, toxicity, and treatment and prevention of mercury exposure.

  5. Altered miRNA expression in the cervix during pregnancy associated with lead and mercury exposure

    Science.gov (United States)

    Sanders, Alison P; Burris, Heather H; Just, Allan C; Motta, Valeria; Amarasiriwardena, Chitra; Svensson, Katherine; Oken, Emily; Solano-Gonzalez, Maritsa; Mercado-Garcia, Adriana; Pantic, Ivan; Schwartz, Joel; Tellez-Rojo, Martha M; Baccarelli, Andrea A; Wright, Robert O

    2015-01-01

    Aim: Toxic metals including lead and mercury are associated with adverse pregnancy outcomes. This study aimed to assess the association between miRNA expression in the cervix during pregnancy with lead and mercury levels. Materials & methods: We obtained cervical swabs from pregnant women (n = 60) and quantified cervical miRNA expression. Women's blood lead, bone lead and toenail mercury levels were analyzed. We performed linear regression to examine the association between metal levels and expression of 74 miRNAs adjusting for covariates. Results: Seventeen miRNAs were negatively associated with toenail mercury levels, and tibial bone lead levels were associated with decreased expression of miR-575 and miR-4286. Conclusion: The findings highlight miRNAs in the human cervix as novel responders to maternal chemical exposure during pregnancy. PMID:26418635

  6. DNA methylation and histone deacetylation regulating insulin sensitivity due to chronic cold exposure.

    Science.gov (United States)

    Wang, Xiaoqing; Wang, Lai; Sun, Yizheng; Li, Ruiping; Deng, Jinbo; Deng, Jiexin

    2017-02-01

    In this study, we investigated the causal relationship between chronic cold exposure and insulin resistance and the mechanisms of how DNA methylation and histone deacetylation regulate cold-reduced insulin resistance. 46 adult male mice from postnatal day 90-180 were randomly assigned to control group and cold-exposure group. Mice in cold-exposure group were placed at temperature from -1 to 4 °C for 30 days to mimic chronic cold environment. Then, fasting blood glucose, blood insulin level and insulin resistance index were measured with enzymatic methods. Immunofluorescent labeling was carried out to visualize the insulin receptor substrate 2 (IRS2), Obese receptor (Ob-R, a leptin receptor), voltage-dependent anion channel protein 1 (VDAC1), cytochrome C (cytC), 5-methylcytosine (5-mC) positive cells in hippocampal CA1 area. Furthermore, the expressions of some proteins mentioned above were detected with Western blot. The results showed: ① Chronic cold exposure could reduce the insulin resistance index (P cold-exposure group than in control group with both immunohistochemical staining and Western blot (P cold exposure increased DNA methylation and histone deacetylation in the pyramidal cells of CA1 area and led to an increase in the expression of histone deacetylase 1 (HDAC1) and DNA methylation relative enzymes (P cold exposure can improve insulin sensitivity, with the involvement of DNA methylation, histone deacetylation and the regulation of mitochondrial energy metabolism. These epigenetic modifications probably form the basic mechanism of cold-reduced insulin resistance. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Mercury biogeochemical cycling in the ocean and policy implications.

    Science.gov (United States)

    Mason, Robert P; Choi, Anna L; Fitzgerald, William F; Hammerschmidt, Chad R; Lamborg, Carl H; Soerensen, Anne L; Sunderland, Elsie M

    2012-11-01

    Anthropogenic activities have enriched mercury in the biosphere by at least a factor of three, leading to increases in total mercury (Hg) in the surface ocean. However, the impacts on ocean fish and associated trends in human exposure as a result of such changes are less clear. Here we review our understanding of global mass budgets for both inorganic and methylated Hg species in ocean seawater. We consider external inputs from atmospheric deposition and rivers as well as internal production of monomethylmercury (CH₃Hg) and dimethylmercury ((CH₃)₂Hg). Impacts of large-scale ocean circulation and vertical transport processes on Hg distribution throughout the water column and how this influences bioaccumulation into ocean food chains are also discussed. Our analysis suggests that while atmospheric deposition is the main source of inorganic Hg to open ocean systems, most of the CH₃Hg accumulating in ocean fish is derived from in situ production within the upper waters (ocean basins are changing at different rates due to differences in atmospheric loading and that the deeper waters of the oceans are responding slowly to changes in atmospheric Hg inputs. Most biological exposures occur in the upper ocean and therefore should respond over years to decades to changes in atmospheric mercury inputs achieved by regulatory control strategies. Migratory pelagic fish such as tuna and swordfish are an important component of CH₃Hg exposure for many human populations and therefore any reduction in anthropogenic releases of Hg and associated deposition to the ocean will result in a decline in human exposure and risk. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Mercury in fish tissue of Idaho lakes vs. those of the Northeastern United States as it relates to the moderating effects of selenium

    Science.gov (United States)

    The primary methyl-mercury (MeHg) exposure mode to wildlife and humans is through the consumption of aquatic organisms, particulary fish. Selenium has been demonstrated to moderate the toxicity of MeHg in every test animal type examined to date. A molar ratio of Se:Hg >1 appear...

  9. Assessment of environmental exposure to mercury in selected human populations as studied by nuclear and other techniques

    International Nuclear Information System (INIS)

    1995-01-01

    A Co-ordinated Research Programme (CRP) on assessment of environmental exposure to mercury in selected human populations as studied by nuclear and other techniques was initiated by the IAEA in 1990. The purpose of this CRP is to promote national and regional studies to evaluate the exposure of selected population groups to mercury and methylmercury and to estimate potential risks in these groups. The programme is focused on the analysis of human head hair for the determination of mercury and methylmercury. The CRP has two main components: (i) identifying population groups that are at risk, and (ii) studying health effects in the exposed persons, particularly pregnant women and the babies born to them. This document reports the discussions held during the third Research Co-ordination Meeting (RCM) for the CRP which took place at the IAEA, Monaco Laboratory. (author)

  10. Developmental neurotoxicity: methylmercury and prenatal exposure protection in the context of the Minamata Convention

    Directory of Open Access Journals (Sweden)

    Ana Boischio

    2015-09-01

    Full Text Available Mercury is a global pollutant of public environmental health concern due to its long-range atmospheric distribution, environmental distribution, and neurotoxic effects. Following biological methylation, methylmercury (MeHg can be un-evenly bioaccumulated within aquatic food chains. Fish consumption can be a significant route of human exposure to MeHg. MeHg exposure in the prenatal stage, at relatively low levels, has recently been established as harmful during neurological development, potentially leading to intellectual disability. The Minamata Convention on Mercury is a global agreement, currently under ratification, to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds. The resolution regarding the role of the World Health Organization and ministries of health in the implementation of the Convention includes protection of human health from critical exposures to MeHg. Riverside populations living in areas with artisanal small-scale gold mining, and relying heavily on fish consumption, have been identified as the most vulnerable population in terms of MeHg exposure and developmental neurotoxicity. This article focuses on the proper design and dissemination of fish advisories within the context of implementation of the Convention.

  11. Mercury Disposition in Suckling Rats: Comparative Assessment Following Parenteral Exposure to Thiomersal and Mercuric Chloride

    Science.gov (United States)

    Blanuša, Maja; Orct, Tatjana; Vihnanek Lazarus, Maja; Sekovanić, Ankica; Piasek, Martina

    2012-01-01

    Due to the facts that thiomersal-containing vaccine is still in use in many developing countries, and all forms of mercury have recognised neurotoxic, nephrotoxic, and other toxic effects, studies on disposition of ethylmercury and other mercury forms are still justified, especially at young age. Our investigation aimed at comparing mercury distribution and rate of excretion in the early period of life following exposure to either thiomersal (TM) or mercuric chloride (HgCl2) in suckling rats. Three experimental groups were studied: control, TM, and HgCl2, with 12 to18 pups in each. Both forms of mercury were administered subcutaneously in equimolar quantities (0.81 μmol/kg b.w.) three times during the suckling period (on the days of birth 7, 9, and 11) to mimic the vaccination regimen in infants. After the last administration of TM or HgCl2, total mercury retention and excretion was assessed during following six days. In TM-exposed group mercury retention was higher in the brain, enteral excretion was similar, and urinary excretion was much lower compared to HgCl2-exposed sucklings. More research is still needed to elucidate all aspects of toxicokinetics and most harmful neurotoxic potential of various forms of mercury, especially in the earliest period of life. PMID:22899883

  12. Mercury genomics in the Arctic Ocean

    Science.gov (United States)

    Bowman, K.; Lamborg, C. H.; Collins, E.; Hammerschmidt, C. R.; Agather, A. M.

    2017-12-01

    Methyl-mercury production in the ocean is likely dependent on microbial activity, however, methylation pathways remain elusive. In the Arctic, high concentrations of methyl-mercury are found in top predator marine mammals and seabirds. As a result of seafood consumption, pregnant women and women of child-bearing age in the Arctic often have blood Hg concentrations that exceed U.S. and Canadian safety guidelines. To understand the chemical cycling of mercury in the Arctic Ocean we participated in the 2015 U.S. GEOTRACES Arctic expedition (GN01) to measure Hg speciation in the water column of the Bering Sea, Makarov basin, and Canada basin between Dutch Harbor, Alaska and the North Pole. At select stations, seawater was filtered through 0.22 µm Sterivex filters and genomic DNA was collected using a phenol-chloroform extraction. Broad-range degenerate PCR primers were used to detect the presence of hgcAB, and clade-specific degenerate quantitative PCR primers were used to determine the abundance of hgcA. Metagenomic sequencing was done at three stations to identify taxonomic and functional groups, and to search for hgcA-like genes that the PCR primers may have missed.

  13. Mercury risk assessment combining internal and external exposure methods for a population living near a municipal solid waste incinerator.

    Science.gov (United States)

    Deng, Chunyan; Xie, Han; Ye, Xuejie; Zhang, Haoran; Liu, Maodian; Tong, Yindong; Ou, Langbo; Yuan, Wen; Zhang, Wei; Wang, Xuejun

    2016-12-01

    Risk assessments for human health have been conducted for municipal solid waste incinerators (MSWIs) in many western countries, whereas only a few risk assessments have been performed for MSWIs in developing countries such as China where the use of waste incineration is increasing rapidly. To assess the mercury exposure risks of a population living near the largest MSWI in South China, we combined internal exposure and external exposure assessment with an individual-specific questionnaire. The mercury concentrations in air, soil, and locally collected food around the MSWI were assessed. The total mercury (T-Hg) and methylmercury (MeHg) of 447 blood samples from a control group, residential exposure group, and MSWI workers were measured. The internal and external exposures of the subject population were analyzed. Significant difference in MeHg concentrations was observed between the control group and the exposed group, between the control group and the MSWI workers, and between the exposed group and the MSWI workers (median levels: 0.70 μg/L, 0.81 μg/L, and 1.02 μg/L for the control group, exposed group, and MSWI workers, respectively). The MeHg/T-Hg ratio was 0.51 ± 0.19, 0.59 ± 0.17 and 0.58 ± 0.25, respectively. Multiple linear regression analysis indicated that MeHg concentrations were positively correlated with the gaseous mercury in the air. Combining internal and external exposure assessment showed that the direct contribution of MSWI emissions was minor compared with the dietary contribution. The external and internal exposures were well matched with each other. This study also suggested that an integrated method combining internal and external exposure assessment with an individual-specific questionnaire is feasible to assess the risks for a population living near a MSWI. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. MERCURY IN FISHERY PRODUCTS FROM CENTRAL ADRIATIC SEA (OFFICIAL CONTROLS FROM 1995 TO 2009

    Directory of Open Access Journals (Sweden)

    C. Ciccarelli

    2011-04-01

    Full Text Available Thanks to its properties, methylmercury is the most bioavailable form of mercury compounds. In fact, it causes the most toxic effects on the immune, cardiovascular, renal and central nervous systems, in particular the fetal brain. Seafood consumption is recognized as being the largest environmental mercury source to most human populations. So, fishery products are the most important source of methylmercury exposure in human. As the mercury burden of fish increases for transference to upper trophic levels (biomagnification, piscivors have the potential to accumulate extremely high mercury loads, in the methylated form, 70 to 100% in the muscular tissues. Reg. CE 1881/2006 sets, lastly, allowed maximum levels of mercury in seafood. Several authors found out an increase of mercury levels with size of carnivorous fishes. But this relationship strictly depends on fish species, and is a result of the interaction between environmental and physiological effects. This paper describes the results of a monitoring of mercury levels in fishery products, from 1995 to 2009, before they were sold by auction in the Wholesale Fish Market in the town of San Benedetto del Tronto. The authors’aim was to set a correlation between increasing fish size (weight and loads of the metal up to maximum levels by law.

  15. Total and methyl mercury concentrations in sediment and water of a constructed wetland in the Athabasca Oil Sands Region

    International Nuclear Information System (INIS)

    Oswald, Claire J.; Carey, Sean K.

    2016-01-01

    In the Athabasca Oil Sands Region in northeastern Alberta, Canada, oil sands operators are testing the feasibility of peatland construction on the post-mining landscape. In 2009, Syncrude Canada Ltd. began construction of the 52 ha Sandhill Fen pilot watershed, including a 15 ha, hydrologically managed fen peatland built on sand-capped soft oil sands tailings. An integral component of fen reclamation is post-construction monitoring of water quality, including salinity, fluvial carbon, and priority pollutant elements. In this study, the effects of fen reclamation and elevated sulfate levels on mercury (Hg) fate and transport in the constructed system were assessed. Total mercury (THg) and methylmercury (MeHg) concentrations in the fen sediment were lower than in two nearby natural fens, which may be due to the higher mineral content of the Sandhill Fen peat mix and/or a loss of Hg through evasion during the peat harvesting, stockpiling and placement processes. Porewater MeHg concentrations in the Sandhill Fen typically did not exceed 1.0 ng L −1 . The low MeHg concentrations may be a result of elevated porewater sulfate concentrations (mean 346 mg L −1 ) and an increase in sulphide concentrations with depth in the peat, which are known to suppress MeHg production. Total Hg and MeHg concentrations increased during a controlled mid-summer flooding event where the water table rose above the ground surface in most of the fen. The Hg dynamics during this event showed that hydrologic fluctuations in this system exacerbate the release of THg and MeHg downstream. In addition, the elevated SO 4 2− concentrations in the peat porewaters may become a problem with respect to downstream MeHg production once the fen is hydrologically connected to a larger wetland network that is currently being constructed. - Highlights: • A constructed fen peatland in the Athabasca Oil Sands Region was studied. • Total and methyl mercury concentrations in fen sediment and waters

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

    Energy Technology Data Exchange (ETDEWEB)

    Li Shunxing, E-mail: lishunxing@fjzs.edu.cn [Department of Chemistry, Zhangzhou Normal University, Zhangzhou 363000 (China); Fujian Province University Key Laboratory of Analytical Science, Zhangzhou Normal University, Zhangzhou (China); Zheng Fengying; Huang Yang [Department of Chemistry, Zhangzhou Normal University, Zhangzhou 363000 (China); Fujian Province University Key Laboratory of Analytical Science, Zhangzhou Normal University, Zhangzhou (China); Ni Jiancong [Department of Chemistry, Zhangzhou Normal University, Zhangzhou 363000 (China)

    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 {mu}g L{sup -1} and 50.0 {mu}g L{sup -1}, respectively, the residual concentrations of mercury could meet the criterion of drinking water (1.0 {mu}g L{sup -1}) and the permitted discharge limit of wastewater (10.0 {mu}g L{sup -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.

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

    International Nuclear Information System (INIS)

    Li Shunxing; Zheng Fengying; Huang Yang; Ni Jiancong

    2011-01-01

    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.

  18. Effects of damming on the distribution and methylation of mercury in Wujiang River, Southwest China.

    Science.gov (United States)

    Zhao, Lei; Guo, Yanna; Meng, Bo; Yao, Heng; Feng, Xinbin

    2017-10-01

    Newly built reservoirs are regarded as sensitive ecosystem for mercury (Hg) methylation. A comprehensive study was conducted to understand the influence of damming on the distribution and methylation of Hg within a river-reservoir ecosystem in Wujiang River Basin (WRB), Southwest China. Hg species in inflow-outflow rivers of six cascade reservoirs were analyzed each month during 2006. Mean concentrations of total Hg (THg) and methylmercury (MeHg) in river water in WRB were 3.41 ± 1.98 ng L -1 and 0.15 ± 0.06 ng L -1 , respectively. THg and particulate Hg (PHg) concentrations in outflow rivers of reservoirs significantly decreased after dam construction, suggesting that a considerable amount of PHg was intercepted by way of sedimentation. However, the influence of damming on the distributions of dissolved Hg (DHg) and reactive Hg (RHg) in rivers was less pronounced. MeHg concentrations in outflow rivers of the older reservoirs significantly increased compared to inflow rivers with the maximum increasing factor of 92%, indicating the active net Hg methylation in the reservoirs. However, the difference between MeHg in inflow rivers and outflow rivers were less pronounced in the newly constructed reservoirs, indicating that these reservoirs were not active sites of Hg methylation. The construction of the cascade reservoirs resulted in the elevation of MeHg in several sections of the Wujiang River, which attributed to the net Hg methylation in reservoirs and discharge of MeHg from hypolimnion. MeHg-enriched water in outflow rivers from hypolimnetic water could be transported to downstream, posing potential threat to the aquatic food web and human health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. A cluster of pediatric metallic mercury exposure cases treated with meso-2,3-dimercaptosuccinic acid (DMSA)

    Science.gov (United States)

    Forman, J; Moline, J; Cernichiari, E; Sayegh, S; Torres, J C; Landrigan, M M; Hudson, J; Adel, H N; Landrigan, P J

    2000-06-01

    Nine children and their mother were exposed to vapors of metallic mercury. The source of the exposure appears to have been a 6-oz vial of mercury taken from a neighbor's home. The neighbor reportedly operated a business preparing mercury-filled amulets for practitioners of the Afro-Caribbean religion Santeria. At diagnosis, urinary mercury levels in the children ranged from 61 to 1,213 microg/g creatinine, with a geometric mean of 214.3 microg/m creatinine. All of the children were asymptomatic. To prevent development of neurotoxicity, we treated the children with oral meso-2,3-dimercaptosuccinic acid (DMSA). During chelation, the geometric mean urine level rose initially by 268% to 573.2 microg mercury/g creatinine (p<0.0005). At the 6-week follow-up examination after treatment, the geometric mean urine mercury level had fallen to 102.1 microg/g creatinine, which was 17.8% of the geometric mean level observed during treatment (p<0.0005) and 47.6% of the original baseline level (p<0.001). Thus, oral chelation with DMSA produced a significant mercury diuresis in these children. We observed no adverse side effects of treatment. DMSA appears to be an effective and safe chelating agent for treatment of pediatric overexposure to metallic mercury.

  20. Occupational Metallic Mercury Poisoning in Gilders

    Directory of Open Access Journals (Sweden)

    M Vahabzadeh

    2016-04-01

    Full Text Available Occupational exposure to elemental mercury vapor usually occurs through inhalation during its utilizations. This leads to a variety of adverse health effects. In some Islamic cities, this type of poisoning may occur during gilding of shrines using elemental mercury with gold. Herein, we report on three male patients aged 20–53 years, who were diagnosed with occupational metallic mercury poisoning due to gilding of a shrine. All patients presented with neuro-psychiatric disorders such as anxiety, loss of memory and concentration, and sleep disorders with high urinary mercury concentrations of 326–760 μg/L upon referring, 3–10 days after cessation of elemental mercury exposure. Following chelating therapy, the patients recovered clinically and their mercury concentrations declined to non-toxic level (<25 μg/L. Health, environmental and labor authorities, as well as the gilders should be aware of the toxicity risk of exposure to metalic mercury during gilding in closed environments and act accordingly.

  1. Associations of maternal long-chain polyunsaturated fatty acids, methyl mercury, and infant development in the Seychelles Child Development Nutrition Study.

    Science.gov (United States)

    Strain, J J; Davidson, Philip W; Bonham, Maxine P; Duffy, Emeir M; Stokes-Riner, Abbie; Thurston, Sally W; Wallace, Julie M W; Robson, Paula J; Shamlaye, Conrad F; Georger, Lesley A; Sloane-Reeves, Jean; Cernichiari, Elsa; Canfield, Richard L; Cox, Christopher; Huang, Li Shan; Janciuras, Joanne; Myers, Gary J; Clarkson, Thomas W

    2008-09-01

    Fish consumption during gestation can provide the fetus with long-chain polyunsaturated fatty acids (LCPUFA) and other nutrients essential for growth and development of the brain. However, fish consumption also exposes the fetus to the neurotoxicant, methyl mercury (MeHg). We studied the association between these fetal exposures and early child development in the Seychelles Child Development Nutrition Study (SCDNS). Specifically, we examined a priori models of Omega-3 and Omega-6 LCPUFA measures in maternal serum to test the hypothesis that these LCPUFA families before or after adjusting for prenatal MeHg exposure would reveal associations with child development assessed by the BSID-II at ages 9 and 30 months. There were 229 children with complete outcome and covariate data available for analysis. At 9 months, the PDI was positively associated with total Omega-3 LCPUFA and negatively associated with the ratio of Omega-6/Omega-3 LCPUFA. These associations were stronger in models adjusted for prenatal MeHg exposure. Secondary models suggested that the MeHg effect at 9 months varied by the ratio of Omega-6/Omega-3 LCPUFA. There were no significant associations between LCPUFA measures and the PDI at 30 months. There were significant adverse associations, however, between prenatal MeHg and the 30-month PDI when the LCPUFA measures were included in the regression analysis. The BSID-II mental developmental index (MDI) was not associated with any exposure variable. These data support the potential importance to child development of prenatal availability of Omega-3 LCPUFA present in fish and of LCPUFA in the overall diet. Furthermore, they indicate that the beneficial effects of LCPUFA can obscure the determination of adverse effects of prenatal MeHg exposure in longitudinal observational studies.

  2. Ranking the contributions of commercial fish and shellfish varieties to mercury exposure in the United States: implications for risk communication.

    Science.gov (United States)

    Groth, Edward

    2010-04-01

    Fish and shellfish have important nutritional benefits, and US per capita seafood consumption has increased substantially since 2002. Recent research has reinforced concerns about adverse effects of methylmercury exposure, suggesting that methylmercury doses associated with typical US rates of fish consumption may pose measurable risks, with no threshold. These converging trends create a need to improve risk communication about fish consumption and mercury. The analysis performed here identifies the relative importance of different fish and shellfish as sources of mercury in the US seafood supply and proposes improved consumer advice, so that the public can benefit from fish consumption while minimizing mercury exposure. I have quantified contributions to total mercury in the US seafood supply by 51 different varieties of fish and shellfish, then ranked and sorted the 51 varieties in terms of relative impact. Except for swordfish, most fish with the highest mercury levels are relatively minor contributors to total inputs. Tuna (canned light, canned albacore and fresh/frozen varieties) accounts for 37.4 percent of total mercury inputs, while two-thirds of the seafood supply and nine of the 11 most heavily consumed fish and shellfish are low or very low in mercury. Substantial improvement in risk communication about mercury in fish and seafood is needed; in particular, several population subsets need better guidance to base their seafood choices more explicitly on mercury content. I have sorted the 51 seafood varieties into six categories based on mercury levels, as a framework for improving risk communication in this regard. (c) 2009 Elsevier Inc. All rights reserved.

  3. PRKCZ methylation is associated with sunlight exposure in a North American but not a Mediterranean population

    Science.gov (United States)

    Sunlight exposure has been shown to alter DNA methylation patterns across several human cell-types, including T-lymphocytes. Since epigenetic changes establish gene expression profiles, changes in DNA methylation induced by sunlight exposure warrant investigation. The purpose of this study was to as...

  4. Influence of prenatal arsenic exposure and newborn sex on global methylation of cord blood DNA.

    Directory of Open Access Journals (Sweden)

    J Richard Pilsner

    Full Text Available BACKGROUND: An emerging body of evidence indicates that early-life arsenic (As exposure may influence the trajectory of health outcomes later in life. However, the mechanisms underlying these observations are unknown. OBJECTIVE: The objective of this study was to investigate the influence of prenatal As exposure on global methylation of cord blood DNA in a study of mother/newborn pairs in Matlab, Bangladesh. DESIGN: Maternal and cord blood DNA were available from a convenience sample of 101 mother/newborn pairs. Measures of As exposure included maternal urinary As (uAs, maternal blood As (mbAs and cord blood As (cbAs. Several measures of global DNA methylation were assessed, including the [3H]-methyl-incorporation assay and three Pyrosequencing assays: Alu, LINE-1 and LUMA. RESULTS: In the total sample, increasing quartiles of maternal uAs were associated with an increase in covariate-adjusted means of newborn global DNA methylation as measured by the [3H]-methyl-incorporation assay (quartile 1 (Q1 and Q2 vs. Q4; p = 0.06 and 0.04, respectively. Sex-specific linear regression analyses, while not reaching significance level of 0.05, indicated that the associations between As exposures and Alu, LINE-1 and LUMA were positive among male newborns (N = 58 but negative among female newborns (N = 43; tests for sex differences were borderline significant for the association of cbAs and mbAs with Alu (p = 0.05 and 0.09, respectively and for the association between maternal uAs and LINE-1 (p = 0.07. Sex-specific correlations between maternal urinary creatinine and newborn methyl-incorporation, Alu and LINE-1 were also evident (p<0.05. CONCLUSIONS: These results suggest that prenatal As exposure is associated with global DNA methylation in cord blood DNA, possibly in a sex-specific manner. Arsenic-induced epigenetic modifications in utero may potentially influence disease outcomes later in life. Additional studies are needed to confirm

  5. Occupational and environmental mercury exposure among small-scale gold miners in the Talensi-Nabdam District of Ghana's Upper East region.

    Science.gov (United States)

    Paruchuri, Yasaswi; Siuniak, Amanda; Johnson, Nicole; Levin, Elena; Mitchell, Katherine; Goodrich, Jaclyn M; Renne, Elisha P; Basu, Niladri

    2010-11-15

    Mercury use in small-scale gold mining is ubiquitous across Ghana but little is known about the extent to which such activities have contaminated community residents and miners. Here, occupational exposures to elemental mercury (via urine sampling) and dietary exposures to methylmercury (via hair sampling) were assessed among 120 participants recruited from a mining community located in the Talensi-Nabdam District of Ghana's Upper East region during summer 2009. More than one-fifth of the participants had moderately high levels of urinary mercury (>10μg/L) and 5% had urine mercury levels that exceeded the WHO guideline value of 50μg/L. When participants were stratified according to occupation, those active in the mining industry had the highest mercury levels. Specifically, individuals that burned amalgam had urine mercury levels (median: 43.8μg/L; mean ± SD: 171.1±296.5μg/L; n=5) significantly higher than median values measured in mechanical operators (11.6μg/L, n=4), concession managers/owners (5.6μg/L, n=11), excavators that blast and chisel ore (4.9μg/L, n=33), individuals that sift and grind crushed ore (2.2μg/L, n=47), support workers (0.5μg/L, n=14), and those with no role in the mining sector (2.5μg/L, n=6). There was a significant positive Spearman correlation between fish consumption and hair mercury levels (r=0.30) but not with urine mercury (r=0.18) though further studies are needed to document which types of fish are consumed as well as portion sizes. Given that 200,000 people in Ghana are involved in the small-scale gold mining industry and that the numbers are expected to grow in Ghana and many other regions of the world, elucidating mercury exposure pathways in such communities is important to help shape policies and behaviors that may minimize health risks. Copyright © 2010 Elsevier B.V. All rights reserved.

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

    OpenAIRE

    Park, Jung-Duck; Zheng, Wei

    2012-01-01

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

  7. Does water-level fluctuation affect mercury methylation in wetland soils?

    Energy Technology Data Exchange (ETDEWEB)

    Branfireun, B.A.; Mitchell, C.P.J.; Iraci, J.M. [Toronto Univ., ON (Canada). Dept. of Geography; Krabbenhoft, D.P. [United States Geological Survey, Middleton, WI (United States); Fowle, D.A. [Kansas Univ., Lawrence, KS (United States). Dept. of Geology; Neudahl, L. [Minnesota Power, Duluth, MN (United States)

    2006-07-01

    Mercury (Hg) concentrations in fish vary considerably in freshwater lakes and reservoirs. However, the variations are not generally consistent with physical factors such as basin characteristics, wetland cover or lake chemistry. Pronounced differences in Hg concentrations in fish have been noted in the reservoirs of the St. Louis River system near Duluth Minnesota. The differences were observed between headwater reservoir systems with seasonal flooding and drawdown, and a peaking reservoir with approximately daily water level fluctuations during seasonal lower flow periods. It was suggested that these differences could be attributed to water level fluctuations in the reservoir which influenced the actual production of methylmercury (MeHg) in the surrounding wetland soils. In response to this hypothesis, the authors investigated the role of water level fluctuation in the production and mobilization of MeHg in sediments from wetlands that lie adjacent to a headwater reservoir, a peaking reservoir, and a nearby natural flowage lake used as a control. Preliminary field surveys of the wetland soils revealed that although the average MeHg concentrations in the headwater and peaking reservoir wetlands were not considerably different, both were much higher than the natural lake. Each site demonstrated high variability, but maximum MeHg concentrations ranged from 29.2 ng/g for the peaking reservoir to 4.44 ng/g at the natural lake. A laboratory experiment was therefore performed in which sediments from each wetland were subjected to different water level regimes. The purpose was to assess Hg methylation potential. Stable Hg isotopes were used at the beginning and end of the experiment. In order to determine if water level fluctuation can significantly change the methylation potential of wetland soils on its own, the microbial consortia will also be assessed during the laboratory experiment.

  8. [Effects of Citric Acid on Activation and Methylation of Mercury in the Soils of Water-Level-Fluctuating Zone of the Three Gorges.Reservoir].

    Science.gov (United States)

    Qin, Cai-qing; Liang, Li; You, Rui; Deng, Han; Wang, Ding-yong

    2015-12-01

    To investigate effects of the main component of vegetation root exudates-citric acid on activation and methylation of mercury in the soil of water-level-fluctuating zone (WLFZ) of the Three Gorges Reservoir area, simulation experiments were conducted by extracting and cultivating soil with different concentrations of citric acid. The results showed that after adding citric acid, the total mercury content in leaching solution before reaching peak were higher than that of the control, and increased with the increase of citric acid concentrations. The maximum amount of mercury complexes increased initially and then reached plateaus with the percentage against the total mercury in soil of 1.03%, 1.67%, 1.99%, 2.47%, 2.68%, 2.73% and 2.73% for different citric acid concentrations (0, 1, 2, 4, 5, 6 and 8 mmol · L⁻¹). In addition, concentrations of methylmercury ( MeHg) in soil remained stable in the first 3 hours, and then increased accompanying with the increasing rate rising with the concentration of citric acid ( besides the control group) . This result indicated that citric acid probably could promote the transformation process from inorganic mercury to MeHg in soil. which increased with the concentration of citric acid.

  9. Within-person reproducibility of red blood cell mercury over a 10- to 15-year period among women in the Nurses' Health Study II

    DEFF Research Database (Denmark)

    Kioumourtzoglou, Marianthi-Anna; Roberts, Andrea L; Nielsen, Flemming

    2016-01-01

    Most epidemiologic studies of methylmercury (MeHg) health effects rely on a single measurement of a MeHg biomarker to assess long-term exposures. Long-term reproducibility data are, therefore, needed to assess the reliability of a single measure to reflect long-term exposures. In this study, we...... assessed within-person reproducibility of red blood cell (RBC) mercury (Hg), a marker of methyl-mercury, over 10-15 years in a sample of 57 women. Fifty-seven women from the Nurses' Health Study II provided two blood samples 10-15-years apart (median: 12 years), which were analyzed for mercury levels...... in the red blood cells (B-Hg*). To characterize within-person reproducibility, we estimated correlation and intraclass correlation coefficients (r and ICC) across the two samples. Further, we compared different prediction models, including variables on fish and seafood consumption, for B-Hg* at the first...

  10. Five Hundred Years of Mercury Exposure and Adaptation

    Science.gov (United States)

    Lombardi, Guido; Lanzirotti, Antonio; Qualls, Clifford; Socola, Francisco; Ali, Abdul-Mehdi; Appenzeller, Otto

    2012-01-01

    Mercury is added to the biosphere by anthropogenic activities raising the question of whether changes in the human chromatin, induced by mercury, in a parental generation could allow adaptation of their descendants to mercury. We review the history of Andean mining since pre-Hispanic times in Huancavelica, Peru. Despite the persistent degradation of the biosphere today, no overt signs of mercury toxicity could be discerned in present day inhabitants. However, mercury is especially toxic to the autonomic nervous system (ANS). We, therefore, tested ANS function and biologic rhythms, under the control of the ANS, in 5 Huancavelicans and examined the metal content in their hair. Mercury levels varied from none to 1.014 ppm, significantly less than accepted standards. This was confirmed by microfocused synchrotron X-ray fluorescence analysis. Biologic rhythms were abnormal and hair growth rate per year, also under ANS control, was reduced (P Peru. This would generally benefit survival in the Anthropocene, the man-made world, we now live in. PMID:22910643

  11. Total mercury levels in hair, toenail, and urine among women free from occupational exposure and their relations to renal tubular function

    International Nuclear Information System (INIS)

    Ohno, Tomoko; Sakamoto, Mineshi; Kurosawa, Tomoko; Dakeishi, Miwako; Iwata, Toyoto; Murata, Katsuyuki

    2007-01-01

    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-β-d-glucosaminidase activity (NAG) and α 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+/-0.91μg/g in hair, 0.59+/-0.32μg/g in toenail, and 0.86+/-0.66μg/g creatinine in urine; and, there were positive correlations among them (P<0.001). The daily mercury intake of 9.15+/-7.84μg/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+/-0.28μg/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 (μg/g)]=2.44x[toenail mercury (μg/g)

  12. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-470 Oyster Sample

    International Nuclear Information System (INIS)

    2016-01-01

    This publication describes the production of the IAEA-470 certified reference material, which was produced following ISO Guide 34:2009, General Requirements for the Competence of Reference Materials Producers. A sample of approximately 10 kg of dried oysters was taken from oysters collected, dissected and freeze-dried by the Korean Ocean Research and Development Institute, and was further processed at the IAEA Environment Laboratories to produce a certified reference material. The sample contained certified mass fractions for arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, mercury, methyl mercury, rubidium, selenium, silver, sodium, strontium, vanadium and zinc. The produced vials containing the processed oyster sample were carefully capped and stored for further certification studies. Between-unit homogeneity and stability during dispatch and storage were quantified in accordance with ISO Guide 35:2006, Reference Materials - General and Statistical Principles for Certification. The material was characterized by laboratories with demonstrated competence and adhering to ISO/IEC 17025:2005. Uncertainties of the certified values were calculated in compliance with the guide to the Expression of Uncerdainty in Measurement (JCGM 100:2008), including uncertainty associated with heterogeneity and instability of the material, and with the characterization itself. The material is intended for the quality control and assessment of method performance. As with any reference material, it can also be used for control charts or validation studies

  13. Hair mercury concentrations of children and mothers in Korea: Implication for exposure and evaluation

    International Nuclear Information System (INIS)

    Kim, S.A.; Jeon, C.K.; Paek, D.M.

    2008-01-01

    Background: Mercury is a global pollutant that affects neurodevelopment of children. Objective: The objectives were to measure and evaluate mercury concentration of children and mothers, and its association with exposure. Methods: A cross-sectional assessment was done using questionnaires and hair mercury were analysed by Cold Vapor Atomic Absorption Spectrometry in the National Institute for Minamata Disease in Japan. Results: A total of 112 children and 111 mothers were included; mean age was 34 months and 32 years, respectively. 17.9 % of children and 34.2 % of mothers had concentrations greater than 1 parts per million (ppm) as reference level. Body weight at birth, feeding methods, maternal age, and maternal education level were significantly different in each group (p < .05). Mean maternal hair mercury level (0.91 ppm) was higher than children (0.74 ppm), and has a positive correlation between them (p < .05). 68.1% of children, 75% of pregnant period, 63.4% of lactating period, and 78.6% of last six months have been consuming fish. With multiple regression analysis, hair mercury levels in children aged less than 6 months had a linear relationship with body weight at birth, gestational weeks, feeding methods (breast- or bottle- feeding) and maternal educational level. While children aged over 6 months significantly differed with gender, frequency of fish servings per week, and frequency of maternal fish consumption in lactation period. And hair mercury levels had inverse linear relationship with maternal monthly income in this age group. Maternal mercury levels had linear relationship with maternal age. Conclusion: Mercury levels in children may be affected by their mothers due to similar dietary patterns. Further long-term large-scale and follow-up studies are needed

  14. Hair mercury concentrations of children and mothers in Korea: Implication for exposure and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.A. [Department of Environmental Health, School of Public Health, Seoul National University, Seoul (Korea, Republic of)], E-mail: heaven1@snu.ac.kr; Jeon, C.K.; Paek, D.M. [Department of Environmental Health, School of Public Health, Seoul National University, Seoul (Korea, Republic of)

    2008-08-25

    Background: Mercury is a global pollutant that affects neurodevelopment of children. Objective: The objectives were to measure and evaluate mercury concentration of children and mothers, and its association with exposure. Methods: A cross-sectional assessment was done using questionnaires and hair mercury were analysed by Cold Vapor Atomic Absorption Spectrometry in the National Institute for Minamata Disease in Japan. Results: A total of 112 children and 111 mothers were included; mean age was 34 months and 32 years, respectively. 17.9 % of children and 34.2 % of mothers had concentrations greater than 1 parts per million (ppm) as reference level. Body weight at birth, feeding methods, maternal age, and maternal education level were significantly different in each group (p < .05). Mean maternal hair mercury level (0.91 ppm) was higher than children (0.74 ppm), and has a positive correlation between them (p < .05). 68.1% of children, 75% of pregnant period, 63.4% of lactating period, and 78.6% of last six months have been consuming fish. With multiple regression analysis, hair mercury levels in children aged less than 6 months had a linear relationship with body weight at birth, gestational weeks, feeding methods (breast- or bottle- feeding) and maternal educational level. While children aged over 6 months significantly differed with gender, frequency of fish servings per week, and frequency of maternal fish consumption in lactation period. And hair mercury levels had inverse linear relationship with maternal monthly income in this age group. Maternal mercury levels had linear relationship with maternal age. Conclusion: Mercury levels in children may be affected by their mothers due to similar dietary patterns. Further long-term large-scale and follow-up studies are needed.

  15. Cadmium, mercury and selenium concentrations in mink (Mustela vison) from Yukon, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Gamberg, Mary [Gamberg Consulting, Box 10460, Whitehorse, Yukon, Y1A 7A1 (Canada)]. E-mail: mary.gamberg@northwestel.net; Boila, Gail [Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB, R3T 2N6 (Canada); Stern, Gary [Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB, R3T 2N6 (Canada); Roach, Patrick [Department of Indian and Northern Affairs, Suite 300, 300 Main Street, Whitehorse, Yukon, Y1A 2B5 (Canada)

    2005-12-01

    Mercury (total and methyl), cadmium and selenium concentrations were measured in liver, kidney and brain tissue from mink trapped from the Yukon Territory from 2001-2002. None of these metals was found at levels of toxicological concern. Total mercury averaged 0.66, 0.92 and 0.22 {mu}g g{sup -1} in mink kidney, liver and brain tissue respectively, while methyl mercury averaged 0.77, 0.85 and 0.21 {mu}g g{sup -1} in the same tissues. Selenium averaged 2.07, 1.40 and 0.39 {mu}g g{sup -1} in mink kidney, liver and brain tissue, while cadmium was only measured in kidneys and averaged 0.22 {mu}g g{sup -1}. All element concentrations are presented on a wet weight basis. Concentrations of total mercury in all tissues were significantly higher in female than male mink, possibly reflecting proportionally greater food consumption by the smaller females. Total mercury concentrations were inversely related to the proportion of mercury present as methylmercury, and positively related to concentrations of selenium, consistent with increasing demethylation of methylmercury, and the formation of mercuric selenide as total concentrations of mercury increased. This relationship was seen most strongly in mink liver, less so in kidneys and not at all in brains where most of the mercury was maintained in the methyl form. There did not appear to be any geographical areas in which mink had obviously higher concentrations of mercury, and there was frequently a relatively large range of mercury levels found in mink from a given trapline. Mink diet may be a factor in this variation. Local environmental levels of cadmium were not reflected in cadmium concentrations in mink tissues. Mercury, cadmium and selenium do not appear to constitute environmental hazards to mink in the Yukon.

  16. Cadmium, mercury and selenium concentrations in mink (Mustela vison) from Yukon, Canada

    International Nuclear Information System (INIS)

    Gamberg, Mary; Boila, Gail; Stern, Gary; Roach, Patrick

    2005-01-01

    Mercury (total and methyl), cadmium and selenium concentrations were measured in liver, kidney and brain tissue from mink trapped from the Yukon Territory from 2001-2002. None of these metals was found at levels of toxicological concern. Total mercury averaged 0.66, 0.92 and 0.22 μg g -1 in mink kidney, liver and brain tissue respectively, while methyl mercury averaged 0.77, 0.85 and 0.21 μg g -1 in the same tissues. Selenium averaged 2.07, 1.40 and 0.39 μg g -1 in mink kidney, liver and brain tissue, while cadmium was only measured in kidneys and averaged 0.22 μg g -1 . All element concentrations are presented on a wet weight basis. Concentrations of total mercury in all tissues were significantly higher in female than male mink, possibly reflecting proportionally greater food consumption by the smaller females. Total mercury concentrations were inversely related to the proportion of mercury present as methylmercury, and positively related to concentrations of selenium, consistent with increasing demethylation of methylmercury, and the formation of mercuric selenide as total concentrations of mercury increased. This relationship was seen most strongly in mink liver, less so in kidneys and not at all in brains where most of the mercury was maintained in the methyl form. There did not appear to be any geographical areas in which mink had obviously higher concentrations of mercury, and there was frequently a relatively large range of mercury levels found in mink from a given trapline. Mink diet may be a factor in this variation. Local environmental levels of cadmium were not reflected in cadmium concentrations in mink tissues. Mercury, cadmium and selenium do not appear to constitute environmental hazards to mink in the Yukon

  17. Geochemical, Genetic, and Community Controls on Mercury

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Judy D.

    2014-11-10

    The sulfate-reducing bacteria (SRB) are soil bacteria that share two common characteristics, strict anaerobiosis and the ability to respire sulfate. The metabolic activities of these bacteria play significant roles in the global sulfur cycle, anaerobic degradation of biomass, biological metal corrosion in the environment and, recently, degradation of toxic compounds. The accumulation of evidence suggests these bacteria are also key to the production of the neurotoxin methylmercury in environmental settings. We propose to use our experience with the development of genetics in sulfate-reducing bacteria of the genus Desulfovibrio to create mutations that will eliminate the methylation of mercury, thereby identifying the genes essential for this process. This information may allow the environmental monitoring of the mercury methylation potential to learn the location and quantity of the production this toxin. From these data, more accurate predictive models of mercury cycling can be generated.

  18. Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis

    Directory of Open Access Journals (Sweden)

    Mortazavi Gh.

    2016-03-01

    Full Text Available According to the World Health Organization (WHO, factors such as growing electricity demand, ever-advancing technologies and changes in social behaviour have led to steadily increasing exposure to man-made electromagnetic fields. Dental amalgam fillings are among the major sources of exposure to elemental mercury vapour in the general population. Although it was previously believed that low levels are mercury (i.g. release of mercury from dental amalgam is not hazardous, now numerous data indicate that even very low doses of mercury cause toxicity. There are some evidence indicating that perinatal exposure to mercury is significantly associated with an increased risk of developmental disorders such as autism spectrum disorders (ASD and attention-deficit hyperactivity disorder (ADHD. Furthermore, mercury can decrease the levels of neurotransmitters dopamine, serotonin, noreprenephrine, and acetylcholine in the brain and cause neurological problems. On the other hand, a strong positive correlation between maternal and cord blood mercury levels is found in some studies. We have previously shown that exposure to MRI or microwave radiation emitted by common mobile phones can lead to increased release of mercury from dental amalgam fillings. Moreover, when we investigated the effects of MRI machines with stronger magnetic fields, our previous findings were confirmed. As a strong association between exposure to electromagnetic fields and mercury level has been found in our previous studies, our findings can lead us to this conclusion that maternal exposure to electromagnetic fields in mothers with dental amalgam fillings may cause elevated levels of mercury and trigger the increase in autism rates. Further studies are needed to have a better understanding of the possible role of the increased mercury level after exposure to electromagnetic fields and the rate of autism spectrum disorders in the offspring.

  19. Accumulation of Mercury (Hg) and Methyl Mercury (Me Hg) Concentrations In Selected Marine Biota From Manjung Coastal Area

    International Nuclear Information System (INIS)

    Anisa Abdullah; Zaini Hamzah; Ahmad Saat; Ahmad Saat; Abd Khalik Wood; Masitah Alias

    2015-01-01

    Level of mercury (Hg) and methyl mercury (Me Hg) in marine ecosystem has been intensively studied as these toxic substances could be accumulated in the marine biota. This study is focusing on the Hg and Me Hg content in marine biota in Manjung coastal area. This area has high potential being affected by rapid socio-economic development of Manjung area such as heavy industrial activities (coal fired power plant, iron foundries, port development and factories), agricultural runoff, waste and toxic discharge, quarries, housing constructions. It may has a potential risk when released into the atmosphere and dispersed on the surface of water and continue deposited at the bottom of the water and sediment and being absorbed by marine biota. The concentrations of Hg and Me Hg in marine ecosystem can be adversely affect human health when it enters the food chain. In this study, five species of marine biota including Johnius dussumieri (Ikan Gelama), Pseudorhombus malayanus (Ikan Sebelah), Arius maculatus (Ikan Duri), Portunus pelagicus (Ketam Renjong) and Charybdis natator (Ketam Salib) were collected during rainy and dry seasons. Measurements were carried out using inductively coupled plasma mass spectrometry (ICP-MS) technique. The Hg concentrations for dry and rainy season are in the range 65.13-102.12 μg/ kg and 75.75-106.10 μg/ kg respectively, while for MeHg concentrations for dry and rainy seasons are in the range 4.35-6.26 μg/ kg and 5.42-6.46 μg/ kg, respectively. These results are below the limit set by Malaysia Food Act (1983). Generally, marine biota from the Manjung coastal area is safe to consume due to low value of ingestion dose rate and health risk index (HRI) for human health. (author)

  20. Occupational and environmental mercury exposure among small-scale gold miners in the Talensi-Nabdam District of Ghana’s Upper East region

    Science.gov (United States)

    Paruchuri, Yasaswi; Siuniak, Amanda; Johnson, Nicole; Levin, Elena; Mitchell, Katherine; Goodrich, Jaclyn M.; Renne, Elisha P.; Basu, Niladri

    2014-01-01

    Mercury use in small-scale gold mining is ubiquitous across Ghana but little is known about the extent to which such activities have contaminated community residents and miners. Here, occupational exposures to elemental mercury (via urine sampling) and dietary exposures to methylmercury (via hair sampling) were assessed among 120 participants recruited from a mining community located in the Talensi-Nabdam District of Ghana’s Upper East region during summer 2009. More than one-fifth of the participants had moderately high levels of urinary mercury (>10 µg/L) and 5% had urine mercury levels that exceeded the WHO guideline value of 50 µg/L. When participants were stratified according to occupation, those active in the mining industry had the highest mercury levels. Specifically, individuals that burned amalgam had urine mercury levels (median: 43.8 µg/L; mean ± SD: 171.1 ± 296.5 µg/L; n=5) significantly higher than median values measured in mechanical operators (11.6 µg/L, n=4), concession managers/owners (5.6 µg/L, n=11), excavators that blast and chisel ore (4.9 µg/L, n=33), individuals that sift and grind crushed ore (2.2 µg/L, n=47), support workers (0.5 µg/L, n=14), and those with no role in the mining sector (2.5 µg/L, n=6). There was a significant positive spearman correlation between fish consumption and hair mercury levels (r = 0.30) but not with urine mercury (r = 0.18) though further studies are needed to document which types of fish are consumed as well as portion sizes. Given that 200,000 people in Ghana are involved in the small-scale gold mining industry and that the numbers are expected to grow in Ghana and many other regions of the world, elucidating mercury exposure pathways in such communities is important to help shape policies and behaviors that may minimize health risks. PMID:20875913

  1. Methylmercury and elemental mercury differentially associate with blood pressure among dental professionals

    Science.gov (United States)

    Goodrich, Jaclyn M.; Wang, Yi; Gillespie, Brenda; Werner, Robert; Franzblau, Alfred; Basu, Niladri

    2013-01-01

    Methylmercury-associated effects on the cardiovascular system have been documented though discrepancies exist, and most studied populations experience elevated methylmercury exposures. No paper has investigated the impact of low-level elemental (inorganic) mercury exposure on cardiovascular risk in humans. The purpose of this study was to increase understanding of the association between mercury exposure (methylmercury and elemental mercury) and blood pressure measures in a cohort of dental professionals that experience background exposures to both mercury forms. Dental professionals were recruited during the 2010 Michigan Dental Association Annual Convention. Mercury levels in hair and urine samples were analyzed as biomarkers of methylmercury and elemental mercury exposure, respectively. Blood pressure (systolic, diastolic) was measured using an automated device. Distribution of mercury in hair (mean, range: 0.45, 0.02–5.18 μg/g) and urine (0.94, 0.03–5.54 μg/L) correspond well with the US National Health and Nutrition Examination Survey. Linear regression models revealed significant associations between diastolic blood pressure (adjusted for blood pressure medication use) and hair mercury (n = 262, p = 0.02). Urine mercury results opposed hair mercury in many ways. Notably, elemental mercury exposure was associated with a significant systolic blood pressure decrease (n = 262, p = 0.04) that was driven by the male population. Associations between blood pressure and two forms of mercury were found at exposure levels relevant to the general population, and associations varied according to type of mercury exposure and gender. PMID:22494934

  2. Total Mercury content of skin toning creams

    African Journals Online (AJOL)

    Administrator

    2008-04-01

    Apr 1, 2008 ... used it for cosmetics (Silberberg, 1995). Mercury- ... Cosmetic preparations containing mercury com- pounds are .... mercury determination by a modified version of an open .... level mercury exposure, which could lead to a.

  3. Holocaust Exposure Induced Intergenerational Effects on FKBP5 Methylation.

    Science.gov (United States)

    Yehuda, Rachel; Daskalakis, Nikolaos P; Bierer, Linda M; Bader, Heather N; Klengel, Torsten; Holsboer, Florian; Binder, Elisabeth B

    2016-09-01

    The involvement of epigenetic mechanisms in intergenerational transmission of stress effects has been demonstrated in animals but not in humans. Cytosine methylation within the gene encoding for FK506 binding protein 5 (FKBP5) was measured in Holocaust survivors (n = 32), their adult offspring (n = 22), and demographically comparable parent (n = 8) and offspring (n = 9) control subjects, respectively. Cytosine-phosphate-guanine sites for analysis were chosen based on their spatial proximity to the intron 7 glucocorticoid response elements. Holocaust exposure had an effect on FKBP5 methylation that was observed in exposed parents as well in their offspring. These effects were observed at bin 3/site 6. Interestingly, in Holocaust survivors, methylation at this site was higher in comparison with control subjects, whereas in Holocaust offspring, methylation was lower. Methylation levels for exposed parents and their offspring were significantly correlated. In contrast to the findings at bin 3/site 6, offspring methylation at bin 2/sites 3 to 5 was associated with childhood physical and sexual abuse in interaction with an FKBP5 risk allele previously associated with vulnerability to psychological consequences of childhood adversity. The findings suggest the possibility of site specificity to environmental influences, as sites in bins 3 and 2 were differentially associated with parental trauma and the offspring's own childhood trauma, respectively. FKBP5 methylation averaged across the three bins examined was associated with wake-up cortisol levels, indicating functional relevance of the methylation measures. This is the first demonstration of an association of preconception parental trauma with epigenetic alterations that is evident in both exposed parent and offspring, providing potential insight into how severe psychophysiological trauma can have intergenerational effects. Published by Elsevier Inc.

  4. Cadmium, lead and mercury exposure in non smoking pregnant women

    International Nuclear Information System (INIS)

    Hinwood, A.L.; Callan, A.C.; Ramalingam, M.; Boyce, M.; Heyworth, J.; McCafferty, P.; Odland, J.Ø.

    2013-01-01

    Recent literature suggests that exposure to low concentrations of heavy metals may affect both maternal and child health. This study aimed to determine the biological heavy metals concentrations of pregnant women as well as environmental and dietary factors that may influence exposure concentrations. One hundred and seventy three pregnant women were recruited from Western Australia, each providing a sample of blood, first morning void urine, residential soil, dust and drinking water samples. Participants also completed a questionnaire which included a food frequency component. All biological and environmental samples were analysed for heavy metals using ICP-MS. Biological and environmental concentrations of lead and mercury were generally low (Median Pb Drinking Water (DW) 0.04 µg/L; Pb soil <3.0 µg/g; Pb dust 16.5 µg/g; Pb blood 3.67 µg/L; Pb urine 0.55; µg/L Hg DW <0.03; Hg soil <1.0 µg/g; Hg dust <1.0 µg/g; Hg blood 0.46 µg/L; Hg urine <0.40 µg/L). Cadmium concentrations were low in environmental samples (Median CdDW 0.02 µg/L; Cdsoil <0.30 ug/g; Cddust <0.30) but elevated in urine samples (Median 0.55 µg/L, creatinine corrected 0.70 µg/g (range <0.2–7.06 µg/g creatinine) compared with other studies of pregnant women. Predictors of increased biological metals concentrations in regression models for blood cadmium were residing in the Great Southern region of Western Australia and not using iron/folic acid supplements and for urinary cadmium was having lower household annual income. However, these factors explained little of the variation in respective biological metals concentrations. The importance of establishing factors that influence low human exposure concentrations is becoming critical in efforts to reduce exposures and hence the potential for adverse health effects. -- Highlights: • Biological heavy metals concentrations in women in their 3rd trimester of pregnancy. • Exposure assessment including environmental, lifestyle and activity

  5. Cadmium, lead and mercury exposure in non smoking pregnant women

    Energy Technology Data Exchange (ETDEWEB)

    Hinwood, A.L., E-mail: a.hinwood@ecu.edu.au [Centre for Ecosystem Management, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027 (Australia); Callan, A. C.; Ramalingam, M.; Boyce, M. [Centre for Ecosystem Management, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027 (Australia); Heyworth, J. [School Population Health, The University of Western Australia, 35 Stirling Highway Crawley, WA 6009 (Australia); McCafferty, P. [ChemCentre, PO Box 1250, Bentley, WA 6983 (Australia); Odland, J. Ø. [Department of Community Medicine, University of Tromsø, N-9037 Tromsø (Norway)

    2013-10-15

    Recent literature suggests that exposure to low concentrations of heavy metals may affect both maternal and child health. This study aimed to determine the biological heavy metals concentrations of pregnant women as well as environmental and dietary factors that may influence exposure concentrations. One hundred and seventy three pregnant women were recruited from Western Australia, each providing a sample of blood, first morning void urine, residential soil, dust and drinking water samples. Participants also completed a questionnaire which included a food frequency component. All biological and environmental samples were analysed for heavy metals using ICP-MS. Biological and environmental concentrations of lead and mercury were generally low (Median Pb Drinking Water (DW) 0.04 µg/L; Pb soil <3.0 µg/g; Pb dust 16.5 µg/g; Pb blood 3.67 µg/L; Pb urine 0.55; µg/L Hg DW <0.03; Hg soil <1.0 µg/g; Hg dust <1.0 µg/g; Hg blood 0.46 µg/L; Hg urine <0.40 µg/L). Cadmium concentrations were low in environmental samples (Median CdDW 0.02 µg/L; Cdsoil <0.30 ug/g; Cddust <0.30) but elevated in urine samples (Median 0.55 µg/L, creatinine corrected 0.70 µg/g (range <0.2–7.06 µg/g creatinine) compared with other studies of pregnant women. Predictors of increased biological metals concentrations in regression models for blood cadmium were residing in the Great Southern region of Western Australia and not using iron/folic acid supplements and for urinary cadmium was having lower household annual income. However, these factors explained little of the variation in respective biological metals concentrations. The importance of establishing factors that influence low human exposure concentrations is becoming critical in efforts to reduce exposures and hence the potential for adverse health effects. -- Highlights: • Biological heavy metals concentrations in women in their 3rd trimester of pregnancy. • Exposure assessment including environmental, lifestyle and activity

  6. Transcriptomics analysis of interactive effects of benzene, trichloroethylene and methyl mercury within binary and ternary mixtures on the liver and kidney following subchronic exposure in the rat

    International Nuclear Information System (INIS)

    Hendriksen, Peter J.M.; Freidig, Andreas P.; Jonker, Diana; Thissen, Uwe; Bogaards, Jan J.P.; Mumtaz, Moiz M.; Groten, John P.; Stierum, Rob H.

    2007-01-01

    The present research aimed to study the interaction of three chemicals, methyl mercury, benzene and trichloroethylene, on mRNA expression alterations in rat liver and kidney measured by microarray analysis. These compounds were selected based on presumed different modes of action. The chemicals were administered daily for 14 days at the Lowest-Observed-Adverse-Effect-Level (LOAEL) or at a two- or threefold lower concentration individually or in binary or ternary mixtures. The compounds had strong antagonistic effects on each other's gene expression changes, which included several genes encoding Phase I and II metabolizing enzymes. On the other hand, the mixtures affected the expression of 'novel' genes that were not or little affected by the individual compounds. The three compounds exhibited a synergistic interaction on gene expression changes at the LOAEL in the liver and both at the sub-LOAEL and LOAEL in the kidney. Many of the genes induced by mixtures but not by single compounds, such as Id2, Nr2f6, Tnfrsf1a, Ccng1, Mdm2 and Nfkb1 in the liver, are known to affect cellular proliferation, apoptosis and tissue-specific function. This indicates a shift from compound specific response on exposure to individual compounds to a more generic stress response to mixtures. Most of the effects on cell viability as concluded from transcriptomics were not detected by classical toxicological endpoints illustrating the benefit of increased sensitivity of assessing gene expression profiling. These results emphasize the benefit of applying toxicogenomics in mixture interaction studies, which yields biomarkers for joint toxicity and eventually can result in an interaction model for most known toxicants

  7. Mercury pollution in Wuchuan mercury mining area, Guizhou, Southwestern China: the impacts from large scale and artisanal mercury mining.

    Science.gov (United States)

    Li, Ping; Feng, Xinbin; Qiu, Guangle; Shang, Lihai; Wang, Shaofeng

    2012-07-01

    To evaluate the environmental impacts from large scale mercury mining (LSMM) and artisanal mercury mining (AMM), total mercury (THg) and methyl mercury (MeHg) were determined in mine waste, ambient air, stream water and soil samples collected from Wuchuan mercury (Hg) mining area, Guizhou, Southwestern China. Mine wastes from both LSMM and AMM contained high THg concentrations, which are important Hg contamination sources to the local environment. Total gaseous mercury (TGM) concentrations in the ambient air near AMM furnaces were highly elevated, which indicated that AMM retorting is a major source of Hg emission. THg concentrations in the stream water varied from 43 to 2100 ng/L, where the elevated values were mainly found in the vicinity of AMM and mine waste heaps of LSMM. Surface soils were seriously contaminated with Hg, and land using types and organic matter played an important role in accumulation and transportation of Hg in soil. The results indicated heavy Hg contaminations in the study area, which were resulted from both LSMM and AMM. The areas impacted by LSMM were concentrated in the historical mining and smelting facilities, while Hg pollution resulted from AMM can be distributed anywhere in the Hg mining area. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  9. Genetic effects of organic mercury compounds. II. Chromosome segregation in Drosophila melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Ramel, C; Magnusson, J

    1969-01-01

    The genetic effect of organic mercury compounds on the fruit fly, Drosophila melanogaster was investigated. Treatments of larvae with methyl and phenyl mercury gave rise to development disturbances. Chromosomal abnormalities were noted.

  10. Mercury Poisoning Linked to Skin Products

    Science.gov (United States)

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

  11. Mercury analysis in hair

    DEFF Research Database (Denmark)

    Esteban, Marta; Schindler, Birgit K; Jiménez-Guerrero, José A

    2015-01-01

    Human biomonitoring (HBM) is an effective tool for assessing actual exposure to chemicals that takes into account all routes of intake. Although hair analysis is considered to be an optimal biomarker for assessing mercury exposure, the lack of harmonization as regards sampling and analytical...... assurance program (QAP) for assessing mercury levels in hair samples from more than 1800 mother-child pairs recruited in 17 European countries. To ensure the comparability of the results, standard operating procedures (SOPs) for sampling and for mercury analysis were drafted and distributed to participating...... laboratories. Training sessions were organized for field workers and four external quality-assessment exercises (ICI/EQUAS), followed by the corresponding web conferences, were organized between March 2011 and February 2012. ICI/EQUAS used native hair samples at two mercury concentration ranges (0...

  12. Some like it cold: microbial transformations of mercury in polar regions

    Directory of Open Access Journals (Sweden)

    Niels Kroer

    2011-12-01

    Full Text Available The contamination of polar regions with mercury that is transported from lower latitudes as inorganic mercury has resulted in the accumulation of methylmercury (MeHg in food chains, risking the health of humans and wildlife. While production of MeHg has been documented in polar marine and terrestrial environments, little is known about the responsible transformations and transport pathways and the processes that control them. We posit that as in temperate environments, microbial transformations play a key role in mercury geochemical cycling in polar regions by: (1 methylating mercury by one of four proposed pathways, some not previously described; (2 degrading MeHg by activities of mercury resistant and other bacteria; and (3 carrying out redox transformations that control the supply of the mercuric ion, the substrate of methylation reactions. Recent analyses have identified a high potential for mercury-resistant microbes that express the enzyme mercuric reductase to affect the production of gaseous elemental mercury when and where daylight is limited. The integration of microbially mediated processes in the paradigms that describe mercury geochemical cycling is therefore of high priority especially in light of concerns regarding the effect of global warming and permafrost thawing on input of MeHg to polar regions.

  13. Mercury speciation and dispersion from an active gold mine at the West Wits area, South Africa.

    Science.gov (United States)

    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.

  14. Mercury exposure in a large subantarctic avian community.

    Science.gov (United States)

    Carravieri, Alice; Cherel, Yves; Blévin, Pierre; Brault-Favrou, Maud; Chastel, Olivier; Bustamante, Paco

    2014-07-01

    Mercury (Hg) contamination poses potential threats to ecosystems worldwide. In order to study Hg bioavailability in the poorly documented southern Indian Ocean, Hg exposure was investigated in the large avian community of Kerguelen Islands. Adults of 27 species (480 individuals) showed a wide range of feather Hg concentrations, from 0.4 ± 0.1 to 16.6 ± 3.8 μg g(-1) dry weight in Wilson's storm petrels and wandering albatrosses, respectively. Hg concentrations increased roughly in the order crustacean- feeding habits' differences of the two age-classes in this species. High Hg concentrations were reported for three species of the poorly known gadfly petrels, which merit further investigation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Multiple experimental approaches of immunotoxic effects of mercury chloride in the blue mussel, Mytilus edulis, through in vivo, in tubo and in vitro exposures

    International Nuclear Information System (INIS)

    Duchemin, Matthieu B.; Auffret, Michel; Wessel, Nathalie; Fortier, Marlene; Morin, Yves; Pellerin, Jocelyne; Fournier, Michel

    2008-01-01

    Biological impairments due to mercury discharge into the environment are now an issue of global concern. From the three forms of mercury found in aquatic ecosystems, the immunotoxic effects of mercury chloride were examined in the model animal, the blue mussel. In order to investigate the toxic potency of this chemical, three exposure regimes were carried out: chronic exposure of groups of individuals, a new protocol 'in tubo' designed for sub-acute exposures of individuals, and acute exposures of target cells. Chronic exposure revealed significant immunotoxic effects after 7 days at 10 -6 M, while acute exposures showed significant inhibition of phagocytosis at 10 -4 M and 10 -3 M. In sub-acute exposures both circulating haemocytes and haemocyte mortality increased at 10 -4 M and 10 -3 M while phagocytosis and the clearance rate drew hormetic toxic effects on healthy individuals. These results suggest the use of the 'in tubo' design for bivalve toxicological individual studies. - HgCl 2 impairs the immune system of test-tube mussels

  16. Reducing surface water total and methyl mercury concentrations and bioavailability using a coagulation-wetland system

    Science.gov (United States)

    Kraus, T. E.; Fleck, J.; Henneberry, Y. K.; Stumpner, E. B.; Krabbenhoft, D. P.; Bachand, P.; Randall, P.

    2013-12-01

    With the recent passage of laws regulating concentrations and loads of mercury (Hg) in surface waters, there is a need to develop management practices that will reduce the export of Hg from both point and non-point sources. Coagulation with metal based salts to remove particles and dissolved organic matter (DOM) from solution is a practice commonly employed by drinking water utilities. Because dissolved Hg is associated with particles and DOM, it follows that Hg should also be removed during the coagulation process and end up associated with the organo-metal precipitate, termed flocculate (floc). The effectiveness of iron- and aluminum-based coagulants for removing both inorganic and methyl mercury (IHg and MeHg, respectively) from solution was demonstrated in laboratory studies conducted on agricultural drainage waters of the Sacramento-San Joaquin Delta: dissolved concentrations of MeHg decreased by 80% while IHg decreased by 97% following coagulation. To test the field application of this technology, samples were collected from the inflows and outflows of wetland treatment cells constructed in the central Delta of California. This replicated field experiment includes three replicates each of three inflow waters treatments: (1) iron sulfate addition, (2) polyaluminum chloride addition, and (3) untreated controls. Water entering and exiting the nine treatment cells was sampled approximately monthly over a 1-year period for total Hg and MeHg in both the dissolved and particulate aqueous phases. Initial results confirm that coagulant addition is removing Hg (total and methyl, particulate and dissolved) from solution and sequestering it in the floc. Seasonal effects on DOM concentration and other factors appear to effect whether passage through the wetland cells alters surface water dissolved organic carbon (DOC) and Hg concentrations. Related studies will examine whether the presence of the floc affects the production and fate of MeHg within the wetland cells. If

  17. Histochemical demonstration of two mercury pools in trout tissues: mercury in kidney and liver after mercuric chloride exposure

    International Nuclear Information System (INIS)

    Baatrup, E.; Nielsen, M.G.; Danscher, G.

    1986-01-01

    Juvenile rainbow trout (Salmo gairdneri) were exposed to 100 ppb mercury (as HgCl 2 ) in the water for 14 days. Concentrations of mercury in water and fish organs were monitored using radiolabeled mercury. Tissues from kidney and liver were fixed, and sections were developed by autometallography, a method whereby accumulations of mercury sulfides and/or mercury selenides are silver amplified. In the kidney, mercury was found within lysosomes and extracellularly in the basal lamina of proximal tubules. In the liver, mercury was found within lysosomes of the hepatocytes. Additional groups of mercury-exposed trout were subjected to selenium (as Na 2 SeO 3 ), administered intraperitoneally 2 hr before fixation. Following this treatment, additional mercury could be visualized in the kidney circulatory system, including glomeruli, and in the nucleus and endoplasmic reticulum of liver cells. It is suggested that the mercury visualized prior to selenium treatment represents inorganic mercury, while additional mercury visualized after selenium administration represents an organic form

  18. Global DNA methylation responses to low dose radiation exposure

    International Nuclear Information System (INIS)

    Newman, M.R.; Ormsby, R.J.; Blyth, B.J.; Sykes, P.J.; Bezak, E.

    2011-01-01

    Full text: High radiation doses cause breaks in the DNA which are considered the critical lesions in initiation of radiation-induced cancer. However, at very low radiation doses relevant for the general public, the induction of such breaks will be rare, and other changes to the DNA such as DNA methylation which affects gene expression may playa role in radiation responses. We are studying global DNA methylation after low dose radiation exposure to determine if low dose radiation has short- and/or long-term effects on chromatin structure. We developed a sensitive high resolution melt assay to measure the levels of DNA methylation across the mouse genome by analysing a stretch of DNA sequence within Long Interspersed Nuclear Elements-I (LINE I) that comprise a very large proportion of the mouse and human genomes. Our initial results suggest no significant short-term or longterm) changes in global NA methylation after low dose whole-body X-radiation of 10 J1Gyor 10 mGy, with a significant transient increase in NA methylation observed I day after a high dose of I Gy. If the low radiation doses tested are inducing changes in bal DNA methylation, these would appear to be smaller than the variation observed between the sexes and following the general stress of the sham-irradiation procedure itself. This research was funded by the Low Dose Radiation Research Program, Biological and Environmental Research, US DOE, Grant DE-FG02-05ER64104 and MN is the recipient of the FMCF/BHP Dose Radiation Research Scholarship.

  19. Disentangling the developmental and neurobehavioural effects of perinatal exposure to a chemical mixture found in blood of Arctic populations: differential toxicity of mixture components

    Energy Technology Data Exchange (ETDEWEB)

    Bowers, W.; Nakai, J.; Yagminas, A.; Chu, I.; Moir, D. [Health Canada (Canada)

    2004-09-15

    The current study was designed to evaluate the neurobehavioral effects of perinatal exposure to a chemical mixture that is based on relative concentrations of persistent organic pollutants found in the blood of Canadian Arctic populations and contains 14 PCB congeners, 12 organochlorine pesticides and methyl mercury. This study compared the effects of the complete mixture with the effects of three major components of the mixture (the PCB component, the organochlorine pesticide component, and the methyl mercury component). By examining a range of neurobehavioural functions over development we also determine if specific neurobehavioural disturbances produced by the mixture can be attributed to components of the mixture and if neurobehavioural effects produced by components of the mixture are altered by concurrent exposure to other components in the mixture. Ninety-two nulliparious female Sprague-Dawley rats served as subjects.

  20. Assessment of levels of mercury in human breast milk in Obuasi Municipality

    International Nuclear Information System (INIS)

    Asamoah-Antwi, Dinah

    2016-07-01

    This study was conducted to assess the levels of mercury in breast milk and its potential health risk to the breastfed infants in Obuasi Municipality. Forty eight (48) individual breast milk samples were collected from mothers in selected health facilities in Obuasi town and it’s environ. Total mercury concentrations were determined in the breast milk samples using advanced mercury analyser (AMA254 Altec s.r.o, in the Czech Republic). Methylmercury levels were determined using high performance liquid chromatography linked to inductively couple plasma mass spectrometry (HPLC-ICP-MS) with isotope dilution. The mean concentrations of Total Hg and Methyl Hg in the breast milk were 0.4043 and 0.1829 μg/L respectively. Total mercury and methylmercury concentrations ranged from 0.080 to 2.320 μg/L and 0.008 to 0.734 μg/L respectively. The estimated intake obtained in this study was lower than the reference dose established by the US EPA (0.3μg/kg/day). However the hazard quotients evaluated showed that the one month old infants had hazard quotient above the 0.2, therefore indicating that there is a potential risk for such infants and need to be managed. It was also found that (65.3%) of the mothers had no knowledge of the exposure route to mercury and it toxicity to humans. (au)

  1. Effects of stream water chemistry and tree species on release and methylation of mercury during litter decomposition.

    Science.gov (United States)

    Tsui, Martin Tsz Ki; Finlay, Jacques C; Nater, Edward A

    2008-12-01

    Foliage of terrestrial plants provides an important energy and nutrient source to aquatic ecosystems but also represents a potential source of contaminants, such as mercury (Hg). In this study, we examined how different stream water types and terrestrial tree species influenced the release of Hg from senesced litter to the water and its subsequent methylation during hypoxic litter decomposition. After laboratory incubations of maple leaf litter for 66 days, we observed 10-fold differences in dissolved Hg (DHg, tree species collected at the same site and incubated with the same source water, litter from slower decomposing species (e.g., cedar and pine) yielded higher DHg concentrations than those with more labile carbon (e.g., maple and birch). Percent MeHg, however, was relatively similar among different leaf species (i.e., 61-86%). Our study is the first to demonstrate that stream water chemistry and terrestrial plant litter characteristics are important factors determining Hg release and methylation during hypoxic litter decomposition. These results suggest that certain watershed and aquatic ecosystem properties can determine the levels of MeHg inputs during litterfall events.

  2. Mercury pOIsonIng

    African Journals Online (AJOL)

    A case of mercury poisoning is reported and clinical observations of 6 .... fish ingested and occupational exposure. .... exposed to mercury as a result of inadequate industrial safety standards, and ... WHO Tech Rep Ser 1980; No. 674: 102-115.

  3. Mercury Spill Responses - Five States, 2012-2015.

    Science.gov (United States)

    Wozniak, Ryan J; Hirsch, Anne E; Bush, Christina R; Schmitz, Stuart; Wenzel, Jeff

    2017-03-17

    Despite measures to educate the public about the dangers of elemental mercury, spills continue to occur in homes, schools, health care facilities, and other settings, endangering the public's health and requiring costly cleanup. Mercury is most efficiently absorbed by the lungs, and exposure to high levels of mercury vapor after a release can cause cough, sore throat, shortness of breath, nausea, vomiting, diarrhea, headaches, and visual disturbances (1). Children and fetuses are most susceptible to the adverse effects of mercury vapor exposure. Because their organ systems are still developing, children have increased respiratory rates, and they are closer to the ground where mercury vapors are most highly concentrated (2). To summarize key features of recent mercury spills and lessons learned, five state health departments involved in the cleanup (Iowa, Michigan, Missouri, North Carolina, and Wisconsin) compiled data from various sources on nonthermometer mercury spills from 2012 to 2015. The most common sites of contamination were residences, schools and school buses, health care facilities, and commercial and industrial facilities. Children aged mercury exposure. To protect the public's health after a mercury spill, it is important that local, state, and federal agencies communicate and coordinate effectively to ensure a quick response, and to minimize the spread of contamination. To reduce the number of mercury spills that occur in the United States, public health officials should increase awareness about exchange programs for mercury-containing items and educate school and health care workers about sources of mercury and how to dispose of them properly.

  4. Global Trends in Mercury Management

    Science.gov (United States)

    Choi, Kyunghee

    2012-01-01

    The United Nations Environmental Program Governing Council has regulated mercury as a global pollutant since 2001 and has been preparing the mercury convention, which will have a strongly binding force through Global Mercury Assessment, Global Mercury Partnership Activities, and establishment of the Open-Ended Working Group on Mercury. The European Union maintains an inclusive strategy on risks and contamination of mercury, and has executed the Mercury Export Ban Act since December in 2010. The US Environmental Protection Agency established the Mercury Action Plan (1998) and the Mercury Roadmap (2006) and has proposed systematic mercury management methods to reduce the health risks posed by mercury exposure. Japan, which experienced Minamata disease, aims vigorously at perfection in mercury management in several ways. In Korea, the Ministry of Environment established the Comprehensive Plan and Countermeasures for Mercury Management to prepare for the mercury convention and to reduce risks of mercury to protect public health. PMID:23230466

  5. FKBP5 methylation as a possible marker for cortisol state and transient cortisol exposure in healthy human subjects.

    Science.gov (United States)

    Winkler, Britta K; Lehnert, Hendrik; Oster, Henrik; Kirchner, Henriette; Harbeck, Birgit

    2017-10-01

    Current glucocorticoid replacement regimens, in adrenal insufficiency, fail to mimic the physiological cortisol secretion, thereby fostering serious side effects. To experimentally evaluate the impact of CpG methylation within the FKBP5 gene as a possible short- and long-term marker for cortisol exposure in humans. An ACTH-stimulation test was carried out and methylation status of the FKBP5 gene in leukocytes was determined. A negative correlation between basal levels of methylation and serum cortisol was observed. Individual changes in FKBP5 methylation after 24 h correlated with cortisol responses. Considering previous studies conducted with murine leucocytes, FKBP5 methylation may be suitable as a long-term biomarker, rather than acute glucocorticoid exposure, also in humans.

  6. Accumulation and fluxes of mercury in terrestrial and aquatic food chains with special reference to Finland

    Directory of Open Access Journals (Sweden)

    Martin Lodenius

    2013-03-01

    Full Text Available Mercury is known for its biomagnification especially in aquatic food chains and for its toxic effects on different organisms including man. In Finland mercury has formerly been used in industry and agriculture and in addition many anthropogenic activities may increase the mercury levels in ecosystems. Phenyl mercury was widely used as slimicide in the pulp and paper industry in the 1950s and 1960s. In the chlor-alkali industry metallic mercury was used as catalyst at three plants. The most toxic form of mercury, methyl mercury, may be formed in soils, water, sediments and organisms. Many factors, including microbial activity, temperature, oxygen status etc., affect the methylation rate. In the lake ecosystem bioaccumulation of methyl mercury is very strong. In early 1980s there was a restriction of fishing concerning approximately 4000 km2 of lakes and sea areas because of mercury pollution. In aquatic systems we still find elevated concentrations near former emission sources. Long-range atmospheric transport and mechanical operations like ditching and water regulation may cause increased levels of mercury in the aquatic ecosystems. In the Finnish agriculture organic mercury compounds were used for seed dressing until 1992. Although the amounts used were substantial the concentrations in agricultural soils have remained rather low. In terrestrial food chains bioaccumulation is normally weak with low or moderate concentration at all ecosystem levels. Due to a weak uptake through roots terrestrial, vascular plants normally contain only small amounts of mercury. There is a bidirectional exchange of mercury between vegetation and atmosphere. Contrary to vascular plants, there is a very wide range of concentrations in fungi. Mercury may pose a threat to human health especially when accumulated in aquatic food chains.

  7. Mercury content in fish from newly impounded reservoirs

    International Nuclear Information System (INIS)

    Frick, K.

    1992-12-01

    During the seventies elevated mercury content in fish was observed in newly created reservoirs although background levels were normal. The initial rise of reservoir mercury levels is probably caused by the dramatically increased amount of organic matter originating from flooded top-soil and vegetation. Mercury is introduced in the food-chain by methylating bacteria that utilize the surplus of organic matter. This microbial methylation is probably also favoured by reductions in oxygen content and pH that accompanies the decomposition of organic material. It is difficult to make reliable estimates of the duration and maximum levels of the elevated mercury levels since the end result is affected by several biological and chemical processes in combination. Variations may occur on the basis of the type and amount of flooded organic and inorganic material, water chemistry, specific combination of fish and residence time of reservoir water. All available preventive and ameliorating measures are untried in reservoir water bodies, at least in large scale experiments. Vegetation and top-soil stripping could be efficient but also very costly. Liming is a possible method in cases of ongoing or expected acidification. Addition of selenium is a potentially powerful way of lowering the mercury content in fish and this method is well suited to neutral water bodies. Large reductions in fish mercury content have been documented, but since selenium also has been shown to have strong negative effects on biota this method is not yet recommended. (57 refs.)

  8. Histochemical demonstration of two mercury pools in trout tissues: mercury in kidney and liver after mercuric chloride exposure

    DEFF Research Database (Denmark)

    Baatrup, E; Nielsen, M G; Danscher, G

    1987-01-01

    Juvenile rainbow trout (Salmo gairdneri) were exposed to 100 ppb mercury (as HgCl2) in the water for 14 days. Concentrations of mercury in water and fish organs were monitored using radiolabeled mercury. Tissues from kidney and liver were fixed, and sections were developed by autometallography......, a method whereby accumulations of mercury sulfides and/or mercury selenides are silver amplified. In the kidney, mercury was found within lysosomes and extracellularly in the basal lamina of proximal tubules. In the liver, mercury was found within lysosomes of the hepatocytes. Additional groups of mercury......-exposed trout were subjected to selenium (as Na2SeO3), administered intraperitoneally 2 hr before fixation. Following this treatment, additional mercury could be visualized in the kidney circulatory system, including glomeruli, and in the nucleus and endoplasmic reticulum of liver cells. It is suggested...

  9. Potential risk to wood storks (Mycteria americana) from mercury in Carolina Bay fish

    International Nuclear Information System (INIS)

    Brant, H.A.; Jagoe, C.H.; Snodgrass, J.W.; Bryan, A.L.; Gariboldi, J.C.

    2002-01-01

    Fish mercury levels from some Carolina bays pose risk to wood stork. - Carolina bays are freshwater wetlands that serve as important feeding habitats for the endangered wood stork (Mycteria americana). Water levels in these bays fluctuate greatly and tend to be acidic and rich in dissolved organic carbon (DOC), factors that favor mercury (Hg) methylation and bioaccumulation in fish. To assess potential risks to wood storks consuming mercury contaminated fish in bays, we sampled fish from 10 bays on the Savannah River Site (SRS), South Carolina, an area with documented use by wood storks. Whole body mercury concentrations in 258 fishes of three species (Erimyzon sucetta, Acantharchus pomotis and Esox americanus) commonly consumed by wood storks were determined. Risk factors for nestlings and free-ranging adults were calculated using published no and lowest observable adverse effect concentration (NOAEC and LOAEC) values for birds. Fish from higher trophic levels and those from wetlands with relatively shallow maximum depths and fluctuating water levels were more likely to exceed NOAEC and LOAEC values. Calculation of exposure rates of nestling wood storks indicated they are at highest risk during the first 10 days of the nestling period. These calculations suggest that there is potential concern for wood storks foraging in relatively shallow bays with fluctuating water levels, even though there is no obvious local source of mercury to these wetlands

  10. Mercury Exposure among Garbage Workers in Southern Thailand

    Directory of Open Access Journals (Sweden)

    Somsiri Decharat

    2012-12-01

    Conclusion: Changing garbage workers’ hygiene habits can reduce urinary mercury levels. Personal hygiene is important, and should be stressed in education programs. Employers should institute engineering controls to reduce urinary mercury levels among garbage workers.

  11. Toxicological exposure of man to environment-borne organomercury compounds via foodstuff of animal origin

    Energy Technology Data Exchange (ETDEWEB)

    Kuehnert, M.; Fuchs, V.; Doelle, E.A.

    1983-01-01

    An assessment was made of the 'background' situation regarding biotope contamination (soil, plants, water) by the heavy metal mercury, with particular attention being given to organomercury compounds which are contained in seed dressing substances. Peculiarities of toxic action and its biological implications are discussed by the example of methylated mercury. Mercury exposure of living farm animals, such as poultry, cattle, and swine, due to indirect contact with seed dressing agents together with aspects of food hygiene and with the legal situation in the GDR are assessed and reported on the basis of experimental findings. Conclusions are suggested for practical handling of results obtained from residue toxicology, with the view to ensuring observance of tolerances in animal-based foodstuff.

  12. Effects of metal-rich particulate matter exposure on exogenous and endogenous viral sequence methylation in healthy steel-workers.

    Science.gov (United States)

    Mercorio, Roberta; Bonzini, Matteo; Angelici, Laura; Iodice, Simona; Delbue, Serena; Mariani, Jacopo; Apostoli, Pietro; Pesatori, Angela Cecilia; Bollati, Valentina

    2017-11-01

    Inhaled particles have been shown to produce systemic changes in DNA methylation. Global hypomethylation has been associated to viral sequence reactivation, possibly linked to the activation of pro-inflammatory pathways occurring after exposure. This observation provides a rationale to investigate viral sequence (both exogenous and endogenous) methylation in association to metal-rich particulate matter exposure. To verify this hypothesis, we chose the Wp promoter of the Epstein-Barr Virus (EBV-Wp) and the promoter of the human-endogenous-retrovirus w (HERV-w), respectively as a paradigm of an exogenous and an endogenous retroviral sequence, to be investigated by bisulfite PCR Pyrosequencing. We enrolled 63 male workers in an electric furnace steel plant, exposed to high level of metal-rich particulate matter. Comparing samples obtained in the first day of a work week (time 0-baseline, after 2 days off work) and the samples obtained after 3 days of work (time 1-post exposure), the mean methylation of EBV-Wp was significantly higher at baseline compared to post-exposure (mean baseline = 56.7%5mC; mean post-exposure = 47.9%5mC; p-value = 0.009), whereas the mean methylation of HERV-w did not significantly differ. Individual exposure to inhalable particles and metals was estimated based on measures in all working areas and time spent by the study subjects in each area. In a regression model adjusted for age, body mass index and smoking, PM and metal components had a positive association with EBV-Wp methylation (i.e. PM10: β = 5.99, p-value < 0.038; nickel: β = 17.82, p-value = 0.02; arsenic: β = 13.59, p-value < 0.015). The difference observed comparing baseline and post-exposure samples may be suggestive of a rapid change in EBV methylation induced by air particles, while correlation between EBV methylation and PM/metal exposure may represent a more stable adaptive mechanism. Future studies investigating a larger panel of viral sequences could better elucidate

  13. Mercury. Yesterday, today, and tomorrow. Pt. 4; Quecksilber gestern, heute, morgen. Mercury ''revisited'' (ein letztes Wiedersehen mit Quecksilber). T. 4

    Energy Technology Data Exchange (ETDEWEB)

    Schweinsberg, Fritz

    2011-07-01

    Mercury is a global pollutant since ancient times - and a priority pollutant today. Concentration and residence time of Hg in the atmosphere especially from coal-fired power plants is assessed diversely; new sources were disclosed, e.g. Athabasca oil sands, Canada. The global Hg cycle is influenced by a warming climate and after polar sunrise: Gaseous elemental mercury is photochemically oxidized to Hg(II). Of special relevance is the formation of methyl-Hg by anaerobic microorganisms in aqueous systems, followed by accumulation in the food-chain. The toxicological effect of methyl-Hg is well documented: Minamata Disease, the Iraqi outbreak, the Faroer and Seychellen-Islands studies. In consuming fish risk and benefits have to be balanced: methyl-Hg vs. omega-3 fatty acids (negative confounding). It is of special importance that the prenatal life is more sensitive to methyl-Hg than is adult life. Methyl-Hg is a well-known neurotoxin, but it also may conceal cardiovascular risk. Anyway, healthy eating includes fish low in methyl-Hg and high in omega-3 fatty acids, e.g. salmon, herring, shrimp. Vaccination may not cause infection, even without Thimerosal. Energy-saving bulb shine thank Hg, and we see sharp. (orig.)

  14. Marine diet and tobacco exposure affects mercury concentrations in pregnant women (I from Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Ramón Gaxiola-Robles

    2014-01-01

    Full Text Available Seafood provides essential polyunsaturated fatty acids (PUFA and other nutrients to pregnant women and their fetus(es while a diet rich in finfish can be a major pathway of monomethyl mercury (MeHg+ exposure. We measured total mercury concentration ([THg] in hair samples provided by 75 women in Baja California Sur (BCS to assess its relationship with age, parity, tobacco smoke exposure, and diet based on survey methodologies. Generalized linear models (GLM were used to explain the possible association of the different variables with [THg] in hair. Median [THg] in hair was 1.52 μg g−1, ranging from 0.12 to 24.19 μg g−1 and varied significantly by segment. Approximately 72% (54/75 of those evaluated exceed 1 μg g−1 [THg] and 8% (6/75 exceed 5 μg g−1 [THg] in hair. Although frequency of fish consumption contributed significantly to explaining hair [THg], fish consumption only explained 43% of [THg] in a GLM incorporating tobacco exposure and body mass index. This study establishes possible relationships among multiple potential sources of exposure and other factors related to [THg] in hair of women in the prenatal period. A more detailed examination of other sources of exposure and factors contributing to [THg] is warranted.

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

    International Nuclear Information System (INIS)

    Perez Catan, Soledad; Guevara, Sergio Ribeiro; Marvin-DiPasquale, Mark; Magnavacca, Cecilia; Cohen, Isaac Marcos; Arribere, Maria

    2007-01-01

    Methodological considerations on the determination of benthic methyl-mercury (CH 3 Hg) production potentials were investigated on lake sediment, using 197 Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and γ-irradiation. Flash freezing showed similar CH 3 Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with γ-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 197 Hg(II) carry-over in the organic extraction and/or [ 197 Hg]CH 3 Hg produced via abiotic reactions. Two CH 3 Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO 4 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

  16. Emotions and personality traits in former mercury miners

    Directory of Open Access Journals (Sweden)

    Darja Kobal Grum

    2005-02-01

    Full Text Available The aim of this study is to evaluate the impact of long-term occupational exposure to elemental mercury vapor (Hg° on the personality traits of ex-mercury miners. The study groups included 53 ex-mercury miners previously exposed to Hg° and 53 age-matched controls. Their previous occupational exposure, as well as some biological indices of actual non-occupational exposure, were evaluated. Miners and controls completed the self-reporting Eysenck Personality Questionnaire (EPQ and the Emotional States Questionnaire (ESQ. Group differences were analyzed through the application of ANOVA software. The relationship between the indices of previous occupational exposure and the observed personality traits was evaluated by machine learning methods (regression trees. The mercury miners were intermittently exposed to Hg° in intervals – cycles for a period of 7-31 years at air Hg° concentrations ranging from 0.14 to 0.45 mg/m3. The miners' mean cycle urine mercury (U-Hg level (range 20–120 μg/L and cumulative U-Hg level (range 1286–21390 μg/L were very high. The present non-occupational exposure to mercury was very low in both groups. The low extraversion and lie scores shown by EPQ suggest that miners are more introverted and sincere. The results obtained from ESQ indicate that mercury miners tend to be more depressive, more rigid in expressing their emotions (indifference, and are likely to have more negative self-concepts than the controls. The tendency towards emotional rigidity, negative self-concept, and partly also introversion seems to be associated with some biological indices of occupational Hg° exposure, but not the lower score of lie found in miners. Higher occupational Hg° exposure (cycles U-Hg level > 38.7 mg/L in interaction with moderate alcohol consumption (<26 ml/day seems to have had a decisive influence on the development of miners' depression. Despite the limitations, long-term intermittent, substantial exposure to Hg° in

  17. Mercury methylation in Sphagnum moss mats and its association with sulfate-reducing bacteria in an acidic Adirondack forest lake wetland.

    Science.gov (United States)

    Yu, Ri-Qing; Adatto, Isaac; Montesdeoca, Mario R; Driscoll, Charles T; Hines, Mark E; Barkay, Tamar

    2010-12-01

    Processes leading to the bioaccumulation of methylmercury (MeHg) in northern wetlands are largely unknown. We have studied various ecological niches within a remote, acidic forested lake ecosystem in the southwestern Adirondacks, NY, to discover that mats comprised of Sphagnum moss were a hot spot for mercury (Hg) and MeHg accumulation (190.5 and 18.6 ng g⁻¹ dw, respectively). Furthermore, significantly higher potential methylation rates were measured in Sphagnum mats as compared with other sites within Sunday Lake's ecosystem. Although MPN estimates showed a low biomass of sulfate-reducing bacteria (SRB), 2.8 × 10⁴ cells mL⁻¹ in mat samples, evidence consisting of (1) a twofold stimulation of potential methylation by the addition of sulfate, (2) a significant decrease in Hg methylation in the presence of the sulfate reduction inhibitor molybdate, and (3) presence of dsrAB-like genes in mat DNA extracts, suggested that SRB were involved in Hg methylation. Sequencing of dsrB genes indicated that novel SRB, incomplete oxidizers including Desulfobulbus spp. and Desulfovibrio spp., and syntrophs dominated the sulfate-reducing guild in the Sphagnum moss mat. Sphagnum, a bryophyte dominating boreal peatlands, and its associated microbial communities appear to play an important role in the production and accumulation of MeHg in high-latitude ecosystems. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  18. Natural and anthropogenic mercury sources and their impact on the air-surface exchange of mercury on regional and global scales

    Energy Technology Data Exchange (ETDEWEB)

    Ebinghaus, R.; Tripathi, R.M.; Wallschlaeger, D.; Lindberg, S.E.

    1998-12-31

    Mercury is outstanding among the global environmental pollutants of continuing concern. Especially in the last decade of the 20th century, environmental scientists, legislators, politicians and the public have become aware of mercury pollution in the global environment. It has often been suggested that anthropogenic emissions are leading to a general increase in mercury on local, regional, and global scales (Lindqvist et al. 1991; Expert Panel 1994). Mercury is emitted into the atmosphere from a number of natural as well as anthropogenic sources. In contrast with most of the other heavy metals, mercury and many of its compounds behave exceptionally in the environment due to their volatility and capability for methylation. Long-range atmospheric transport of mercury, its transformation to more toxic methylmercury compounds, and their bioaccumulation in the aquatic foodchain have motivated intensive research on mercury as a pollutant of global concern. Mercury takes part in a number of complex environmental cycles, and special interest is focused on the aquatic-biological and the atmospheric cycles. (orig./SR)

  19. Natural and anthropogenic mercury sources and their impact on the air-surface exchange of mercury on regional and global scales

    Energy Technology Data Exchange (ETDEWEB)

    Ebinghaus, R; Tripathi, R M; Wallschlaeger, D; Lindberg, S E

    1999-12-31

    Mercury is outstanding among the global environmental pollutants of continuing concern. Especially in the last decade of the 20th century, environmental scientists, legislators, politicians and the public have become aware of mercury pollution in the global environment. It has often been suggested that anthropogenic emissions are leading to a general increase in mercury on local, regional, and global scales (Lindqvist et al. 1991; Expert Panel 1994). Mercury is emitted into the atmosphere from a number of natural as well as anthropogenic sources. In contrast with most of the other heavy metals, mercury and many of its compounds behave exceptionally in the environment due to their volatility and capability for methylation. Long-range atmospheric transport of mercury, its transformation to more toxic methylmercury compounds, and their bioaccumulation in the aquatic foodchain have motivated intensive research on mercury as a pollutant of global concern. Mercury takes part in a number of complex environmental cycles, and special interest is focused on the aquatic-biological and the atmospheric cycles. (orig./SR)

  20. Inorganic mercury exposure in drinking water alters essential metal homeostasis in pregnant rats without altering rat pup behavior.

    Science.gov (United States)

    Oliveira, Cláudia S; Oliveira, Vitor A; Costa, Lidiane M; Pedroso, Taíse F; Fonseca, Mariana M; Bernardi, Jamile S; Fiuza, Tiago L; Pereira, Maria E

    2016-10-01

    The aim of this work was to investigate the effects of HgCl 2 exposure in the doses of 0, 10 and 50μg Hg 2+ /mL in drinking water during pregnancy on tissue essential metal homeostasis, as well as the effects of HgCl 2 exposure in utero and breast milk on behavioral tasks. Pregnant rats exposed to both inorganic mercury doses presented high renal Hg content and an increase in renal Cu and hepatic Zn levels. Mercury exposure increased fecal Hg and essential metal contents. Pups exposed to inorganic Hg presented no alterations in essential metal homeostasis or in behavioral task markers of motor function. In conclusion, this work showed that the physiologic pregnancy and lactation states protected the offspring from adverse effects of low doses of Hg 2+ . This protection is likely to be related to the endogenous scavenger molecule, metallothionein, which may form an inert complex with Hg 2+ . Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Fracked ecology: Response of aquatic trophic structure and mercury biomagnification dynamics in the Marcellus Shale Formation.

    Science.gov (United States)

    Grant, Christopher James; Lutz, Allison K; Kulig, Aaron D; Stanton, Mitchell R

    2016-12-01

    Unconventional natural gas development and hydraulic fracturing practices (fracking) are increasing worldwide due to global energy demands. Research has only recently begun to assess fracking impacts to surrounding environments, and very little research is aimed at determining effects on aquatic biodiversity and contaminant biomagnification. Twenty-seven remotely-located streams in Pennsylvania's Marcellus Shale basin were sampled during June and July of 2012 and 2013. At each stream, stream physiochemical properties, trophic biodiversity, and structure and mercury levels were assessed. We used δ15N, δ13C, and methyl mercury to determine whether changes in methyl mercury biomagnification were related to the fracking occurring within the streams' watersheds. While we observed no difference in rates of biomagnificaion related to within-watershed fracking activities, we did observe elevated methyl mercury concentrations that were influenced by decreased stream pH, elevated dissolved stream water Hg values, decreased macroinvertebrate Index for Biotic Integrity scores, and lower Ephemeroptera, Plecoptera, and Trichoptera macroinvertebrate richness at stream sites where fracking had occurred within their watershed. We documented the loss of scrapers from streams with the highest well densities, and no fish or no fish diversity at streams with documented frackwater fluid spills. Our results suggest fracking has the potential to alter aquatic biodiversity and methyl mercury concentrations at the base of food webs.

  2. Impacts of Mercury Pollution Controls on Atmospheric Mercury Concentration and Occupational Mercury Exposure in a Hospital.

    Science.gov (United States)

    Li, Ping; Yang, Yan; Xiong, Wuyan

    2015-12-01

    Mercury (Hg) and Hg-containing products are used in a wide range of settings in hospitals. Hg pollution control measures were carried out in the pediatric ward of a hospital to decrease the possibility of Hg pollution occurring and to decrease occupational Hg exposure. Total gaseous Hg (TGM) concentrations in the pediatric ward and hair and urine Hg concentrations for the pediatric staff were determined before and after the Hg pollution control measures had been implemented. A questionnaire survey performed indicated that the pediatric staff had little understanding of Hg pollution and that appropriate disposal techniques were not always used after Hg leakage. TGM concentrations in the pediatric ward and urine Hg (UHg) concentrations for the pediatric staff were 25.7 and 22.2% lower, respectively, after the Hg pollution control measures had been implemented than before, which indicated that the control measures were effective. However, TGM concentrations in the pediatric ward remained significantly higher than background concentrations and UHg concentrations for the pediatric staff were remained significantly higher than the concentrations in control group, indicating continued existence of certain Hg pollution.

  3. Methylation of mercury in earthworms and the effect of mercury on the associated bacterial communities.

    Science.gov (United States)

    Rieder, Stephan Raphael; Brunner, Ivano; Daniel, Otto; Liu, Bian; Frey, Beat

    2013-01-01

    Methylmercury compounds are very toxic for most organisms. Here, we investigated the potential of earthworms to methylate inorganic-Hg. We hypothesized that the anaerobic and nutrient-rich conditions in the digestive tracts of earthworm's promote the methylation of Hg through the action of their gut bacteria. Earthworms were either grown in sterile soils treated with an inorganic (HgCl2) or organic (CH3HgCl) Hg source, or were left untreated. After 30 days of incubation, the total-Hg and methyl-Hg concentrations in the soils, earthworms, and their casts were analyzed. The impact of Hg on the bacterial community compositions in earthworms was also studied. Tissue concentrations of methyl-Hg in earthworms grown in soils treated with inorganic-Hg were about six times higher than in earthworms grown in soils without Hg. Concentrations of methyl-Hg in the soils and earthworm casts remained at significantly lower levels suggesting that Hg was mainly methylated in the earthworms. Bacterial communities in earthworms were mostly affected by methyl-Hg treatment. Terminal-restriction fragments (T-RFs) affiliated to Firmicutes were sensitive to inorganic and methyl-Hg, whereas T-RFs related to Betaproteobacteria were tolerant to the Hg treatments. Sulphate-reducing bacteria were detected in earthworms but not in soils.

  4. From tails to toes: developing nonlethal tissue indicators of mercury exposure in five amphibian species.

    Science.gov (United States)

    Pfleeger, Adam Z; Eagles-Smith, Collin A; Kowalski, Brandon M; Herring, Garth; Willacker, James J; Jackson, Allyson K; Pierce, John R

    2016-04-01

    Exposure to environmental contaminants has been implicated as a factor in global amphibian decline. Mercury (Hg) is a particularly widespread contaminant that biomagnifies in amphibians and can cause a suite of deleterious effects. However, monitoring contaminant exposure in amphibian tissues may conflict with conservation goals if lethal take is required. Thus, there is a need to develop non-lethal tissue sampling techniques to quantify contaminant exposure in amphibians. Some minimally invasive sampling techniques, such as toe-clipping, are common in population-genetic research, but it is unclear if these methods can adequately characterize contaminant exposure. We examined the relationships between mercury (Hg) concentrations in non-lethally sampled tissues and paired whole-bodies in five amphibian species. Specifically, we examined the utility of three different tail-clip sections from four salamander species and toe-clips from one anuran species. Both tail and toe-clips accurately predicted whole-body THg concentrations, but the relationships differed among species and the specific tail-clip section or toe that was used. Tail-clips comprised of the distal 0-2 cm segment performed the best across all salamander species, explaining between 82 and 92% of the variation in paired whole-body THg concentrations. Toe-clips were less effective predictors of frog THg concentrations, but THg concentrations in outer rear toes accounted for up to 79% of the variability in frog whole-body THg concentrations. These findings suggest non-lethal sampling of tails and toes has potential applications for monitoring contaminant exposure and risk in amphibians, but care must be taken to ensure consistent collection and interpretation of samples.

  5. Hippocampal Dysfunction Provoked by Mercury Chloride Exposure: Evaluation of Cognitive Impairment, Oxidative Stress, Tissue Injury and Nature of Cell Death

    Directory of Open Access Journals (Sweden)

    Walessa Alana Bragança Aragão

    2018-01-01

    Full Text Available Mercury (Hg is a highly toxic metal, which can be found in its inorganic form in the environment. This form presents lower liposolubility and lower absorption in the body. In order to elucidate the possible toxicity of inorganic Hg in the hippocampus, we investigated the potential of low doses of mercury chloride (HgCl2 to promote hippocampal dysfunction by employing a chronic exposure model. For this, 56 rats were exposed to HgCl2 (0.375 mg/kg/day via the oral route for 45 days. After the exposure period, the animals were submitted to the cognitive test of fear memory. The hippocampus was collected for the measurement of total Hg levels, analysis of oxidative stress, and evaluation of cytotoxicity, apoptosis, and tissue injury. It was observed that chronic exposure to inorganic Hg promotes an increase in mercury levels in this region and damage to short- and long-term memory. Furthermore, we found that this exposure model provoked oxidative stress, which led to cytotoxicity and cell death by apoptosis, affecting astrocytes and neurons in the hippocampus. Our study demonstrated that inorganic Hg, even with its low liposolubility, is able to produce deleterious effects in the central nervous system, resulting in cognitive impairment and hippocampal damage when administered for a long time at low doses in rats.

  6. DMPS (DIMAVAL) as a challenge test to assess the mercury and arsenic body/kidney load in humans and as a treatment of mercury toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Aposhian, H.V.; Maiorino, R.M.; Aposhian, M.M. [Univ. of Arizona, Tucson, AZ (United States); Hurlbut, K.M. [Rocky Mountain Poison Control Center, Denver, CO (United States)] [and others

    1996-12-31

    Mercury is an element which, with its compounds, is hazardous and is found in hazardous wastes. In Order to develop suitable diagnostic and therapeutic agents for mercury exposure, we have sought alternative test systems. We have used the chelating agent 2,3-dimercaptopropane-1-sulfonate (DMPS, DIMAVAL{reg_sign}) for estimating the body burden of mercury in normal humans and in dental personnel in a developing country, and for detoxifying humans with mercurous chloride exposure. Use of the DMPS-mercury challenge test has shown that two-thirds of the mercury excreted in the urine of volunteers with dental amalgams appears to be derived from the mercury vapor released from their amalgams. The DMPS challenge test (300 mg, by mouth, after an 11 hr fast) was useful for monitoring dental personnel for mercury vapor exposure. The DMPS challenge test was given to 11 factory workers who make a skin lotion that contains mercurous chloride, 8 users of the skin lotion, and 9 controls. The increases in urinary Hg resulting from the DMPS challenge were 45, 87, and 38-fold, respectively. The results demonstrate that in humans exposed to mercurous chloride, the DMPS-mercury challenge test is of value for a more realistic estimation of mobilizable Hg. DMPS should be considered for use to determine mercury body burdens and to treat humans exposed to mercury and its compounds via exposure to hazardous wastes. 42 refs., 2 figs., 5 tabs.

  7. Assessing mercury exposure and effects to American dippers in headwater streams near mining sites.

    Science.gov (United States)

    Henny, Charles J; Kaiser, James L; Packard, Heidi A; Grove, Robert A; Taft, Michael R

    2005-10-01

    To evaluate mercury (Hg) exposure and possible adverse effects of Hg on American dipper (Cinclus mexicanus) reproduction, we collected eggs and nestling feathers and the larval/nymph form of three Orders of aquatic macroinvertebrates (Ephemeroptera, Plecoptera and Trichoptera = EPT) important in their diet from three major headwater tributaries of the upper Willamette River, Oregon in 2002. The Coast Fork Willamette River is contaminated with Hg due to historical cinnabar (HgS) mining at the Black Butte Mine; the Row River is affected by past gold-mining operations located within the Bohemia Mining District, where Hg was used in the amalgamation process to recover gold; and the Middle Fork Willamette River is the reference area with no known mining. Methyl mercury (MeHg) concentrations (geometric mean) in composite EPT larvae (111.9 ng/g dry weight [dw] or 19.8 ng/g wet weight [ww]), dipper eggs (38.5 ng/g ww) and nestling feathers (1158 ng/g ww) collected from the Coast Fork Willamette were significantly higher than MeHg concentrations in EPT and dipper samples from other streams. Total mercury (THg) concentrations in surface sediments along the same Hg-impacted streams were investigated by others in 1999 (Row River tributaries) and 2002 (Coast Fork). The reported sediment THg concentrations paralleled our biological findings. Dipper breeding territories at higher elevations had fewer second clutches; however, dipper reproductive success along all streams (including the lower elevation and most Hg-contaminated Coast Fork), was judged excellent compared to other studies reviewed. Furthermore, MeHg concentrations in EPT samples from this study were well below dietary concentrations in other aquatic bird species, such as loons and ducks, reported to cause Hg-related reproductive problems. Our data suggest that either dipper feathers or EPT composites used to project MeHg concentrations in dipper feathers (with biomagnification factor of 10-20x) may be used, but with

  8. Prenatal chemical exposures and child language development.

    Science.gov (United States)

    Dzwilewski, Kelsey L C; Schantz, Susan L

    2015-01-01

    The goal of this review is to summarize the evidence that prenatal and/or early postnatal exposure to certain chemicals, both manmade (insulating materials, flame retardants, pesticides) and naturally occurring (e.g., lead, mercury), may be associated with delays or impairments in language development. We focus primarily on a subset of more extensively studied chemicals-polychlorinated biphenyls (PCBs), lead, and methyl mercury-for which a reasonable body of literature on neurodevelopmental outcomes is available. We also briefly summarize the smaller body of evidence for other chemicals including polybrominated diphenyl ether flame retardants (PBDEs) and organophosphate pesticides. Very few studies have used specific assessments of language development and function. Therefore, we included discussion of aspects of cognitive development such as overall intellectual functioning and verbal abilities that rely on language, as well as aspects of cognition such as verbal and auditory working memory that are critical underpinnings of language development. A high percentage of prospective birth cohort studies of PCBs, lead, and mercury have reported exposure-related reductions in overall IQ and/or verbal IQ that persist into middle or late childhood. Given these findings, it is important that clinicians and researchers in communication sciences and disorders are aware of the potential for environmental chemicals to impact language development. The goal of this review is to summarize the evidence that prenatal and/or early postnatal exposure to certain chemicals may be associated with delays or impairments in language development. Readers will gain an understanding of the literature suggesting that early exposure to polychlorinated biphenyls (PCBs), lead, and mercury may be associated with decrements in cognitive domains that depend on language or are critical for language development. We also briefly summarize the smaller body of evidence regarding polybrominated diphenyl

  9. Biomonitoring of airborne mercury with perennial ryegrass cultures

    International Nuclear Information System (INIS)

    Temmerman, Ludwig de; Claeys, Natacha; Roekens, Edward; Guns, Marc

    2007-01-01

    A biomonitoring network with grass cultures was established near a chlor-alkali plant and the mercury concentration in the cultures were compared with the average atmospheric total gaseous mercury (TGM). Biomonitoring techniques based on different exposure periods were carried out. When comparing the mercury concentration in the grass cultures, both the average atmospheric TGM concentration during exposure and the exposure time determined to a large extent the accumulation rate of TGM. The maximum tolerable level of mercury in grass (≅110 μg kg -1 DM) corresponds with an average TGM concentration of 11 ng m -3 for 28 days exposure. The background concentrations in grass were on an average 15 μg kg -1 DM and the effect detection limit (EDL) was 30 μg kg -1 DM. This value corresponds with an average TGM concentration of 3.2 and 4.2 ng m -3 for 28 and 14 days exposure, respectively, which is in turn the biological detection limit (BDL) of ambient TGM. Exposures for 7 days were less appropriate for biomonitoring. - Grass accumulates TGM as a function of the atmospheric concentration and exposure time

  10. A comprehensive assessment of mercury exposure in penguin populations throughout the Southern Hemisphere: Using trophic calculations to identify sources of population-level variation.

    Science.gov (United States)

    Brasso, Rebecka L; Chiaradia, André; Polito, Michael J; Raya Rey, Andrea; Emslie, Steven D

    2015-08-15

    The wide geographic distribution of penguins (Order Sphenisciformes) throughout the Southern Hemisphere provided a unique opportunity to use a single taxonomic group as biomonitors of mercury among geographically distinct marine ecosystems. Mercury concentrations were compared among ten species of penguins representing 26 geographically distinct breeding populations. Mercury concentrations were relatively low (⩽2.00ppm) in feathers from 18/26 populations considered. Population-level differences in trophic level explained variation in mercury concentrations among Little, King, and Gentoo penguin populations. However, Southern Rockhopper and Magellanic penguins breeding on Staten Island, Tierra del Fuego, had the highest mercury concentrations relative to their conspecifics despite foraging at a lower trophic level. The concurrent use of stable isotope and mercury data allowed us to document penguin populations at the greatest risk of exposure to harmful concentrations of mercury as a result of foraging at a high trophic level or in geographic 'hot spots' of mercury availability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Mercury methylation influenced by areas of past mercury mining in the Terlingua district, Southwest Texas, USA

    International Nuclear Information System (INIS)

    Gray, John E.; Hines, Mark E.; Biester, Harald

    2006-01-01

    Speciation and microbial transformation of Hg was studied in mine waste from abandoned Hg mines in SW Texas to evaluate the potential for methyl-Hg production and degradation in mine wastes. In mine waste samples, total Hg, ionic Hg 2+ , Hg 0 , methyl-Hg, organic C, and total S concentrations were measured, various Hg compounds were identified using thermal desorption pyrolysis, and potential rates of Hg methylation and methyl-Hg demethylation were determined using isotopic-tracer methods. These data are the first reported for Hg mines in this region. Total Hg and methyl-Hg concentrations were also determined in stream sediment collected downstream from two of the mines to evaluate transport of Hg and methylation in surrounding ecosystems. Mine waste contains total Hg and methyl-Hg concentrations as high as 19,000 μg/g and 1500 ng/g, respectively, which are among the highest concentrations reported at Hg mines worldwide. Pyrolysis analyses show that mine waste contains variable amounts of cinnabar, metacinnabar, Hg 0 , and Hg sorbed onto particles. Methyl-Hg concentrations in mine waste correlate positively with ionic Hg 2+ , organic C, and total S, which are geochemical parameters that influence processes of Hg cycling and methylation. Net methylation rates were as high as 11,000 ng/g/day, indicating significant microbial Hg methylation at some sites, especially in samples collected inside retorts. Microbially-mediated methyl-Hg demethylation was also observed in many samples, but where both methylation and demethylation were found, the potential rate of methylation was faster. Total Hg concentrations in stream sediment samples were generally below the probable effect concentration of 1.06 μg/g, the Hg concentration above which harmful effects are likely to be observed in sediment dwelling organisms; whereas total Hg concentrations in mine waste samples were found to exceed this concentration, although this is a sediment quality guideline and is not directly

  12. Probabilistic meta-analysis of risk from the exposure to Hg in artisanal gold mining communities in Colombia.

    Science.gov (United States)

    De Miguel, Eduardo; Clavijo, Diana; Ortega, Marcelo F; Gómez, Amaia

    2014-08-01

    Colombia is one of the largest per capita mercury polluters in the world as a consequence of its artisanal gold mining activities. The severity of this problem in terms of potential health effects was evaluated by means of a probabilistic risk assessment carried out in the twelve departments (or provinces) in Colombia with the largest gold production. The two exposure pathways included in the risk assessment were inhalation of elemental Hg vapors and ingestion of fish contaminated with methyl mercury. Exposure parameters for the adult population (especially rates of fish consumption) were obtained from nation-wide surveys and concentrations of Hg in air and of methyl-mercury in fish were gathered from previous scientific studies. Fish consumption varied between departments and ranged from 0 to 0.3 kg d(-1). Average concentrations of total mercury in fish (70 data) ranged from 0.026 to 3.3 μg g(-1). A total of 550 individual measurements of Hg in workshop air (ranging from risk. All but two of the distributions of Hazard Quotients (HQ) associated with ingestion of Hg-contaminated fish for the twelve regions evaluated presented median values higher than the threshold value of 1 and the 95th percentiles ranged from 4 to 90. In the case of exposure to Hg vapors, minimum values of HQ for the general population exceeded 1 in all the towns included in this study, and the HQs for miner-smelters burning the amalgam is two orders of magnitude higher, reaching values of 200 for the 95th percentile. Even acknowledging the conservative assumptions included in the risk assessment and the uncertainties associated with it, its results clearly reveal the exorbitant levels of risk endured not only by miner-smelters but also by the general population of artisanal gold mining communities in Colombia. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Cadmium, lead, and mercury exposure assessment among croatian consumers of free-living game.

    Science.gov (United States)

    Lazarus, Maja; Prevendar Crnić, Andreja; Bilandžić, Nina; Kusak, Josip; Reljić, Slaven

    2014-09-29

    Free-living game can be an important source of dietary cadmium and lead; the question is whether exposure to these two elements is such that it might cause adverse health effects in the consumers. The aim of this study was to estimate dietary exposure to cadmium, lead, and mercury from free-living big game (fallow deer, roe deer, red deer, wild boar, and brown bear), and to mercury from small game (pheasant and hare), hunted in Croatia from 1990 to 2012. The exposure assessment was based on available literature data and our own measurements of metal levels in the tissues of the game, by taking into account different consumption frequencies (four times a year, once a month and once a week). Exposure was expressed as percentage of (provisional) tolerable weekly intake [(P)TWI] values set by the European Food Safety Authority (EFSA). Consumption of game meat (0.002-0.5 % PTWI) and liver (0.005-6 % PTWI) assumed for the general population (four times a year) does not pose a health risk to consumers from the general population, nor does monthly (0.02-6 % PTWI) and weekly (0.1-24 % PTWI) consumption of game meat. However, because of the high percentage of free-living game liver and kidney samples exceeding the legislative limits for cadmium (2-99 %) and lead (1-82 %), people should keep the consumption of certain game species' offal as low as possible. Children and pregnant and lactating women should avoid eating game offal altogether. Free-living game liver could be an important source of cadmium if consumed on a monthly basis (3-74 % TWI), and if consumed weekly (11-297 % TWI), it could even give rise to toxicological concern.

  14. Mercury Exposure and Health Problems in Urban Artisanal Gold Mining (UAGM in Makassar, South Sulawesi, Indonesia

    Directory of Open Access Journals (Sweden)

    Hasriwiani Habo Abbas

    2017-06-01

    Full Text Available Urban artisanal gold mining (UAGM in Makassar, South Sulawesi, Indonesia, has been run by a number of urban gold workers with gold jewelry manufacture as its core activity. The wastes generated from goldsmiths’ activities were further processed by the gold smelters to recover fine gold particles. Smelting gold doré, amalgamation, and burning out the amalgam were the mercury-based gold process usually applied in their work. While working the gold workers are, therefore, potentially exposed to a source of mercury pollution that may cause health problems because of working without proper protection. The aims of this research are to characterize the process of urban artisanal gold mining with the potential mercury exposures during the process, and to assess the health of the gold workers. The results showed that the gold workers had a low educational background, but a relatively high income. The total mercury concentration of gold workers was higher than the control group. They were exposed to intoxicatingly high levels of mercury with the average total mercury concentrations of 6.6 and 10.8 µg/g in the hair of indirect and direct exposed workers, respectively. The health assessment showed that 85% of the gold workers suffered neurological symptoms, such as tremors, and 44%–56% of them experienced restricted fields of vision, slow reflexes, sensory disturbances, unbalanced rigidity, and ataxia. The results also showed that the working years have reasonable correlation with the sum of the positive findings in the 10 neurological symptoms.

  15. Toxic Effects of Mercury on the Cardiovascular and Central Nervous Systems

    Directory of Open Access Journals (Sweden)

    Bruna Fernandes Azevedo

    2012-01-01

    Full Text Available Environmental contamination has exposed humans to various metal agents, including mercury. This exposure is more common than expected, and the health consequences of such exposure remain unclear. For many years, mercury was used in a wide variety of human activities, and now, exposure to this metal from both natural and artificial sources is significantly increasing. Many studies show that high exposure to mercury induces changes in the central nervous system, potentially resulting in irritability, fatigue, behavioral changes, tremors, headaches, hearing and cognitive loss, dysarthria, incoordination, hallucinations, and death. In the cardiovascular system, mercury induces hypertension in humans and animals that has wide-ranging consequences, including alterations in endothelial function. The results described in this paper indicate that mercury exposure, even at low doses, affects endothelial and cardiovascular function. As a result, the reference values defining the limits for the absence of danger should be reduced.

  16. Toxic Effects of Mercury on the Cardiovascular and Central Nervous Systems

    Science.gov (United States)

    Fernandes Azevedo, Bruna; Barros Furieri, Lorena; Peçanha, Franck Maciel; Wiggers, Giulia Alessandra; Frizera Vassallo, Paula; Ronacher Simões, Maylla; Fiorim, Jonaina; Rossi de Batista, Priscila; Fioresi, Mirian; Rossoni, Luciana; Stefanon, Ivanita; Alonso, María Jesus; Salaices, Mercedes; Valentim Vassallo, Dalton

    2012-01-01

    Environmental contamination has exposed humans to various metal agents, including mercury. This exposure is more common than expected, and the health consequences of such exposure remain unclear. For many years, mercury was used in a wide variety of human activities, and now, exposure to this metal from both natural and artificial sources is significantly increasing. Many studies show that high exposure to mercury induces changes in the central nervous system, potentially resulting in irritability, fatigue, behavioral changes, tremors, headaches, hearing and cognitive loss, dysarthria, incoordination, hallucinations, and death. In the cardiovascular system, mercury induces hypertension in humans and animals that has wide-ranging consequences, including alterations in endothelial function. The results described in this paper indicate that mercury exposure, even at low doses, affects endothelial and cardiovascular function. As a result, the reference values defining the limits for the absence of danger should be reduced. PMID:22811600

  17. Mercury biomethylation assessment in the estuary of Bilbao (North of Spain)

    International Nuclear Information System (INIS)

    Raposo, J.C.; Ozamiz, G.; Etxebarria, N.; Tueros, I.; Munoz, C.; Muela, A.; Arana, I.; Barcina, I.

    2008-01-01

    The relationship between the microbial methylation of mercury and the microbial activities in sediments and water collected from the estuary of Bilbao (North of Spain) was studied in three different sampling points and in two different seasons. Three different cultures were prepared with a sediment slurry to distinguish between biotic and abiotic methylation pathways and the variations of the methylmercury concentration and the variations of the population of total number of bacteria (TDC), anaerobic heterotrophic bacteria (AHB), sulphate-reducing bacteria (SRB) and Desulfovibrio were measured. From this work, it can be concluded that the variation of MeHg concentrations is a result of the methylation/demethylation processes in the sediments, and that the abiotic processes have a negligible contribution to those processes. According to the statistical analysis of the results (partial least squares analysis) a significant statistical correlation was established between methylmercury and the SRB counts. - The methylation of mercury follows a stationary pattern linked to the variation of sulphate-reducing bacteria

  18. Intake of mercury through fish consumption

    International Nuclear Information System (INIS)

    Sarmani, S.B.; Kiprawi, A.Z.; Ismail, R.B.; Hassan, R.B.; Wood, A.K.; Rahman, S.A.

    1995-01-01

    Fish has been known as a source of non-occupational mercury exposure to fish consuming population groups, and this is shown by the high hair mercury levels. In this study, hair samples collected from fishermen and their families, and commercial marine fishes were analyzed for mercury and methylmercury by neutron activation and gas chromatography. The results showed a correlation between hair mercury levels and fish consumption patterns. The levels of mercury found in this study were similar to those reported by other workers for fish consuming population groups worldwide. (author)

  19. Subacute effects of low dose lead nitrate and mercury chloride exposure on kidney of rats.

    Science.gov (United States)

    Apaydın, Fatma Gökçe; Baş, Hatice; Kalender, Suna; Kalender, Yusuf

    2016-01-01

    Lead nitrate and mercury chloride are the most common heavy metal pollutants. In the present study, the effects of lead and mercury induced nephrotoxicity were studied in Wistar rats. Lead nitrate (LN, 45 mg/kg b.w/day) and mercury chloride (MC, 0.02 mg/kg b.w/day) and their combination were administered orally for 28 days. Four groups of rats were used in the study: control, LN, MC and LN plus MC groups. Serum biochemical parameters, lipid peroxidation, antioxidant enzymes and histopathological changes in kidney tissues were investigated in all treatment groups. LN and MC caused severe histopathological changes. It was shown that LN, MC and also co-treatment with LN and MC exposure induced significant increase in serum urea, uric acid and creatinine levels. There were also statistically significant changes in antioxidant enzyme activities (SOD, CAT, GPx and GST) and lipid peroxidation (MDA) in all groups except control group. In this study, we showed that MC caused more harmful effects than LN in rats. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Mercury accumulation in placenta and foetal membranes. A study of dental workers and their babies

    Energy Technology Data Exchange (ETDEWEB)

    Wannag, A; Skjaerasen, J

    1975-01-01

    To investigate the hazards of exposure to levels of elementary mercury lower than the present TLV value (0.05 mg/m/sup 3/) a group of dental workers and a nonexposed group were studied. The amount of mercury in blood from mothers and babies at the time of delivery was similar. The exposed group had increased mercury content in placenta and fetal membranes. Mercury accumulation in these organs might serve as a protection for the fetus against mercury exposure. Since exposure to sub-TLV concentrations of elemental mercury during pregnancy will not be reflected in blood mercury content at the time of delivery, the amount of mercury in placenta and fetal membranes might serve as a biological indicator of such exposure.

  1. Epigenetic modulation upon exposure of lung fibroblasts to TiO2 and ZnO nanoparticles: alterations in DNA methylation

    Directory of Open Access Journals (Sweden)

    Patil NA

    2016-09-01

    Full Text Available Nayana A Patil,1,2 WN Gade,2 Deepti D Deobagkar1 1Department of Zoology, Molecular Biology Research Laboratory, Centre of Advanced Studies, 2Department of Biotechnology, Proteomic Research Laboratory, Savitribai Phule Pune University, Pune, India Abstract: Titanium dioxide (TiO2 and zinc oxide (ZnO nanoparticles (NPs are promising candidates for numerous applications in consumer products. This will lead to increased human exposure, thus posing a threat to human health. Both these types of NPs have been studied for their cell toxicity, immunotoxicity, and genotoxicity. However, effects of these NPs on epigenetic modulations have not been studied. Epigenetics is an important link in the genotype and phenotype modulation and misregulation can often lead to lifestyle diseases. In this study, we have evaluated the DNA methylation-based epigenetic changes upon exposure to various concentrations of NPs. The investigation was designed to evaluate global DNA methylation, estimating the corresponding methyltransferase activity and expression of Dnmt gene using lung fibroblast (MRC5 cell line as lungs are the primary route of entry and target of occupational exposure to TiO2 and ZnO NPs. Enzyme-linked immunosorbent assay-based immunochemical assay revealed dose-related decrease in global DNA methylation and DNA methyltransferase activity. We also found direct correlation between the concentration of NPs, global methylation levels, and expression levels of Dnmt1, 3A, and 3B genes upon exposure. This is the first study to investigate effect of exposure to TiO2 and ZnO on DNA methylation levels in MRC5 cells. Epigenetic processes are known to play an important role in reprogramming and adaptation ability of an organism and can have long-term consequences. We suggest that changes in DNA methylation can serve as good biomarkers for early exposure to NPs since they occur at concentrations well below the sublethal levels. Our results demonstrate a clear

  2. A comprehensive assessment of mercury exposure in penguin populations throughout the Southern Hemisphere: Using trophic calculations to identify sources of population-level variation

    International Nuclear Information System (INIS)

    Brasso, Rebecka L.; Chiaradia, André; Polito, Michael J.; Raya Rey, Andrea; Emslie, Steven D.

    2015-01-01

    Highlights: • Mercury concentrations documented for 10 species of penguins (26 breeding populations). • Mercury concentrations ⩽2.00 ppm in feathers from 18/26 penguin populations. • Trophic level calculations revealed source of population-level variation in mercury. • First documentation of geographic mercury ‘hotspots’ for penguin populations. - Abstract: The wide geographic distribution of penguins (Order Sphenisciformes) throughout the Southern Hemisphere provided a unique opportunity to use a single taxonomic group as biomonitors of mercury among geographically distinct marine ecosystems. Mercury concentrations were compared among ten species of penguins representing 26 geographically distinct breeding populations. Mercury concentrations were relatively low (⩽2.00 ppm) in feathers from 18/26 populations considered. Population-level differences in trophic level explained variation in mercury concentrations among Little, King, and Gentoo penguin populations. However, Southern Rockhopper and Magellanic penguins breeding on Staten Island, Tierra del Fuego, had the highest mercury concentrations relative to their conspecifics despite foraging at a lower trophic level. The concurrent use of stable isotope and mercury data allowed us to document penguin populations at the greatest risk of exposure to harmful concentrations of mercury as a result of foraging at a high trophic level or in geographic ‘hot spots’ of mercury availability

  3. Avian mercury exposure and toxicological risk across western North America: A synthesis

    Science.gov (United States)

    Ackerman, Joshua T.; Eagles-Smith, Collin A.; Herzog, Mark; Hartman, Christopher; Peterson, Sarah; Evers, David C.; Jackson, Allyson K.; Elliott, John E.; Vander Pol, Stacy S.; Bryan, Colleen E.

    2016-01-01

    Methylmercury contamination of the environment is an important issue globally, and birds are useful bioindicators for mercury monitoring programs. The available data on mercury contamination of birds in western North America were synthesized. Original data from multiple databases were obtained and a literature review was conducted to obtain additional mercury concentrations. In total, 29219 original bird mercury concentrations from 225 species were compiled, and an additional 1712 mean mercury concentrations, representing 19998 individuals and 176 species, from 200 publications were obtained. To make mercury data comparable across bird tissues, published equations of tissue mercury correlations were used to convert all mercury concentrations into blood-equivalent mercury concentrations. Blood-equivalent mercury concentrations differed among species, foraging guilds, habitat types, locations, and ecoregions. Piscivores and carnivores exhibited the greatest mercury concentrations, whereas herbivores and granivores exhibited the lowest mercury concentrations. Bird mercury concentrations were greatest in ocean and salt marsh habitats and lowest in terrestrial habitats. Bird mercury concentrations were above toxicity benchmarks in many areas throughout western North America, and multiple hotspots were identified. Additionally, published toxicity benchmarks established in multiple tissues were summarized and translated into a common blood-equivalent mercury concentration. Overall, 66% of birds sampled in western North American exceeded a blood-equivalent mercury concentration of 0.2 μg/g wet weight (ww; above background levels), which is the lowest-observed effect level, 28% exceeded 1.0 μg/g ww (moderate risk), 8% exceeded 3.0 μg/g ww (high risk), and 4% exceeded 4.0 μg/g ww (severe risk). Mercury monitoring programs should sample bird tissues, such as adult blood and eggs, that are most-easily translated into tissues with well-developed toxicity benchmarks and that

  4. Environmental and occupational exposures to mercury among indigenous people in Dunkwa-On-Offin, a small scale gold mining area in the South-West of Ghana.

    Science.gov (United States)

    Kwaansa-Ansah, E E; Basu, N; Nriagu, J O

    2010-11-01

    Total mercury concentrations in human hair and urine samples were determined to ascertain the extent of environmental and occupational mercury exposure in Dunkwa-On-Offin, a small scale gold mining area of the central-west region of Ghana. In all ninety-four (94) hair and urine samples comprising of forty (40) small scale miners and fifty-four (54) farmers were collected and analyzed for their total mercury levels using the cold vapour atomic absorption spectrometry. The hair total mercury concentrations ranged from 0.63 to 7.19 ug/g with a mean of 2.35 ± 1.58 ug/g for the farmers and 0.57-6.07 ug/g with a mean of 2.14 ± 1.53 ug/g for the small scale gold miners. There was no significant correlation between the total mercury concentration and the average weekly fish diet. The total mercury concentrations in urine of the miners were higher than those of the farmers and ranged from 0.32 to 3.62 ug/L with a mean of 1.23 ± 0.86 ug/L. The urine concentrations of farmers ranged from 0.075 to 2.31 ug/L with a mean of 0.69 ± 0.39 ug/L. Although the results indicate elevated internal dose of mercury the current levels of exposures do not appear to pose a significant health threat to the people.

  5. Oral and dental affections in mercury-exposed workers

    Energy Technology Data Exchange (ETDEWEB)

    Fahmy, M.S.

    1978-07-01

    A total of 222 mercury-exposed workers in the Chlor-Alkali plant in Kuwait were investigated for oral and dental affections. The levels of mercury-vapor ranged from 566.6 microgram/m3 to 0.3 microgram/m3 in different parts of the factory. The periods of exposure varied from 1 to 11 years. Although the level of mercury vapor in the air and the period of exposure proved to be the main factors as regards the oral signs and symptoms, the oral hygiene condition and the individual sensitivity played substantial roles. Oral affections were found not to be due to allergy to mercury.

  6. Mercury risk in poultry in the Wanshan Mercury Mine, China

    International Nuclear Information System (INIS)

    Yin, Runsheng; Zhang, Wei; Sun, Guangyi; Feng, Zhaohui; Hurley, James P.; Yang, Liyuan; Shang, Lihai; Feng, Xinbin

    2017-01-01

    In this study, total mercury (THg) and methylmercury (MeHg) concentrations in muscles (leg and breast), organs (intestine, heart, stomach, liver) and blood were investigated for backyard chickens, ducks and geese of the Wanshan Mercury Mine, China. THg in poultry meat products range from 7.9 to 3917.1 ng/g, most of which exceeded the Chinese national standard limit for THg in meat (50 ng/g). Elevated MeHg concentrations (0.4–62.8 ng/g) were also observed in meat products, suggesting that poultry meat can be an important human MeHg exposure source. Ducks and geese showed higher Hg levels than chickens. For all poultry species, the highest Hg concentrations were observed in liver (THg: 23.2–3917.1 ng/g; MeHg: 7.1–62.8 ng/g) and blood (THg: 12.3–338.0 ng/g; MeHg: 1.4–17.6 ng/g). We estimated the Hg burdens in chickens (THg: 15.3–238.1 μg; MeHg: 2.2–15.6 μg), ducks (THg: 15.3–238.1 μg; MeHg: 3.5–14.7 μg) and geese (THg: 83.8–93.4 μg; MeHg: 15.4–29.7 μg). To not exceed the daily intake limit for THg (34.2 μg/day) and MeHg (6 μg/day), we suggested that the maximum amount (g) for chicken leg, breast, heart, stomach, intestine, liver, and blood should be 1384, 1498, 2315, 1214, 1081, 257, and 717, respectively; the maximum amount (g) for duck leg, breast, heart, stomach, intestine, liver, and blood should be 750, 1041, 986, 858, 752, 134, and 573, respectively; and the maximum amount (g) for goose leg, breast, heart, stomach, intestine, liver, and blood should be 941, 1051, 1040, 1131, 964, 137, and 562, respectively. - Highlights: • Elevated mercury levels were observed in poultry from Wanshan Mercury Mine, China. • Ducks and geese showed higher mercury levels than chickens. • Liver and blood showed the highest mercury levels. • Poultry can be an important dietary Hg exposure source for local residents. - High levels of Hg associated with poultry surrounding the Wanshan Mercury Mine pose a great risk of Hg exposure to

  7. A downstream voyage with mercury

    Science.gov (United States)

    Heinz, Gary

    2016-01-01

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

  8. Developmental toxicity from exposure to various forms of mercury compounds in medaka fish (Oryzias latipes embryos

    Directory of Open Access Journals (Sweden)

    Wu Dong

    2016-08-01

    Full Text Available This study examined developmental toxicity of different mercury compounds, including some used in traditional medicines. Medaka (Oryzias latipes embryos were exposed to 0.001–10 µM concentrations of MeHg, HgCl2, α-HgS (Zhu Sha, and β-HgS (Zuotai from stage 10 (6–7 hpf to 10 days post fertilization (dpf. Of the forms of mercury in this study, the organic form (MeHg proved the most toxic followed by inorganic mercury (HgCl2, both producing embryo developmental toxicity. Altered phenotypes included pericardial edema with elongated or tube heart, reduction of eye pigmentation, and failure of swim bladder inflation. Both α-HgS and β-HgS were less toxic than MeHg and HgCl2. Total RNA was extracted from survivors three days after exposure to MeHg (0.1 µM, HgCl2 (1 µM, α-HgS (10 µM, or β-HgS (10 µM to examine toxicity-related gene expression. MeHg and HgCl2 markedly induced metallothionein (MT and heme oxygenase-1 (Ho-1, while α-HgS and β-HgS failed to induce either gene. Chemical forms of mercury compounds proved to be a major determinant in their developmental toxicity.

  9. Degradation of methyl and ethyl mercury into inorganic mercury by other reactive oxygen species besides hydroxyl radical

    Energy Technology Data Exchange (ETDEWEB)

    Suda, Ikuo; Takahashi, Hitoshi (Kumamoto Univ. Medical School (Japan). Inst. for Medical Immunology)

    1992-01-01

    Degradation of methyl mercury (MeHg) and ethyl Hg (EtHg) with reactive oxygens was studied in vitro by using peroxidase-hydrogen peroxide (H{sub 2}O{sub 2})-halide and rose bengal-ultraviolet light A systems. For this purpose, the direct determination method for inorganic Hg was employed. Both systems could effectively degrade EtHg, and MeHg to some extent. Degradation of MeHg and EtHg with the myeloperoxidase (MPO)-H{sub 2}O{sub 2}-chloride system was inhibited by MPO inhibitors (cyanide and azide), catalase, hypochlorous acid (HOCl) scavengers (glycine, alanine, serine and taurine), 1,4-diazabicyclo(2,2,2)octane and 2,5-dimethylfuran, but not by hydroxyl radical scavengers (ethanol and mannitol). Iodide was more effective than chloride as the halide component. Lactoperoxidase (LPO) could substitute for MPO in the iodide, but not the chloride system. With MPO-H{sub 2}O{sub 2}-chloride, MPO-H{sub 2}O{sub 2}-iodide and LPO-H{sub 2}O{sub 2}-iodide systems, we observed the increased degradation of EtHg in deuterium oxide (D{sub 2}O) medium better than that in H{sub 2}O medium. The D{sub 2}O effect upon MeHg degradation was extremely weak. These results suggested that HOCl (or HOI) might be also capable of degrading MeHg and EtHg, besides the hydroxyl radical already reported by us. Singlet oxygen could degrade EtHg but not MeHg. (orig.).

  10. Prenatal lead, cadmium and mercury exposure and associations with motor skills at age 7 years in a UK observational birth cohort.

    Science.gov (United States)

    Taylor, Caroline M; Emond, Alan M; Lingam, Raghu; Golding, Jean

    2018-08-01

    Lead and mercury are freely transferred across the placenta, while cadmium tends to accumulate in the placenta. Each contributes to adverse neurological outcomes for the child. Although prenatal heavy metal exposure has been linked with an array of neurodevelopmental outcomes in childhood, its association with the development of motor skills in children has not been robustly studied. The aim of the present study was to investigate the association between prenatal exposure to lead, cadmium and mercury, measured as maternal blood concentrations during pregnancy, and motor skills, measured as subtests of the Movement Assessment Battery for Children (Movement ABC) at age 7 years in a large sample of mother-child pairs enrolled in a UK observational birth cohort study (Avon Longitudinal Study of Parents and Children, ALSPAC). Whole blood samples from pregnant women enrolled in ALSPAC were analysed for lead, cadmium and mercury. In a complete case analysis (n = 1558), associations between prenatal blood concentrations and child motor skills assessed by Movement ABC subtests of manual dexterity, ball skills and balance at 7 years were examined in adjusted regression models. Associations with probable developmental coordination disorder (DCD) were also investigated. The mean prenatal blood levels were: lead 3.66 ± 1.55 μg/dl; cadmium 0.45 ± 0.54 μg/l; mercury 2.23 ± 1.14 μg/l. There was no evidence for any adverse associations of prenatal lead, cadmium or mercury exposure with motor skills measured at age 7 years with Movement ABC subtests in adjusted regression models. Further, there were no associations with probable DCD. There was no evidence to support a role of prenatal exposure to heavy metals at these levels on motor skills in the child at age 7 years measured using the Movement ABC. Early identification of symptoms of motor skills impairment is important, however, to enable investigation, assessment and treatment. Copyright

  11. Placental promoter methylation of DNA repair genes and prenatal exposure to particulate air pollution: an ENVIRONAGE cohort study

    Directory of Open Access Journals (Sweden)

    Kristof Y Neven, MSc

    2018-04-01

    Full Text Available Summary: Background: Exposure to particulate air pollution has been linked with risk of carcinogenesis. Damage to repair pathways might have long-term adverse health effects. We aimed to investigate the association of prenatal exposure to air pollution with placental mutation rate and the DNA methylation of key placental DNA repair genes. Methods: This cohort study used data from the ongoing ENVironmental Influence ON early AGEing (ENVIRONAGE birth cohort, which enrols pairs of mothers and neonates (singleton births only at the East-Limburg Hospital (Genk, Belgium. Placental DNA samples were collected after birth. We used bisulfite-PCR-pyrosequencing to investigate the mutation rate of Alu (a marker for overall DNA mutation and DNA methylation in the promoter genes of key DNA repair and tumour suppressor genes (APEX1, OGG1, PARP1, ERCC1, ERCC4, p53, and DAPK1. We used a high-resolution air pollution model to estimate exposure to particulate matter with a diameter less than 2·5 μm (PM2·5, black carbon, and NO2 over the entire pregnancy on the basis of maternal address. Alu mutation was analysed with a linear regression model, and methylation values of the selected genes were analysed in mixed-effects models. Effect estimates are presented as the relative percentage change in methylation for an ambient air pollution increment of one IQR (ie, the difference between the first and third quartiles of exposure in the entire cohort. Findings: 500 biobanked placental DNA samples were randomly selected from 814 pairs of mothers and neonates who were recruited to the cohort between Feb 1, 2010, and Dec 31, 2014, of which 463 samples met the pyrosequencing quality control criteria. IQR exposure increments were 3·84 μg/m3 for PM2·5, 0·36 μg/m3 for black carbon, and 5·34 μg/m3 for NO2. Among these samples, increased Alu mutation rate was associated with greater exposure to PM2·5 (r=0·26, p<0·0001 and black carbon (r=0·33, p<0·0001, but not NO2

  12. Changes in miRNA Expression Profiling during Neuronal Differentiation and Methyl Mercury-Induced Toxicity in Human in Vitro Models

    Directory of Open Access Journals (Sweden)

    Giorgia Pallocca

    2014-08-01

    Full Text Available MicroRNAs (miRNAs are implicated in the epigenetic regulation of several brain developmental processes, such as neurogenesis, neuronal differentiation, neurite outgrowth, and synaptic plasticity. The main aim of this study was to evaluate whether miRNA expression profiling could be a useful approach to detect in vitro developmental neurotoxicity. For this purpose, we assessed the changes in miRNA expression caused by methyl mercury chloride (MeHgCl, a well-known developmental neurotoxicant, comparing carcinoma pluripotent stem cells (NT-2 with human embryonic stem cells (H9, both analyzed during the early stage of neural progenitor commitment into neuronal lineage. The data indicate the activation of two distinct miRNA signatures, one activated upon neuronal differentiation and another upon MeHgCl-induced toxicity. Particularly, exposure to MeHgCl elicited, in both neural models, the down-regulation of the same six out of the ten most up-regulated neuronal pathways, as shown by the up-regulation of the corresponding miRNAs and further assessment of gene ontology (GO term and pathway enrichment analysis. Importantly, some of these common miRNA-targeted pathways defined in both cell lines are known to play a role in critical developmental processes, specific for neuronal differentiation, such as axon guidance and neurotrophin-regulated signaling. The obtained results indicate that miRNAs expression profiling could be a promising tool to assess developmental neurotoxicity pathway perturbation, contributing towards improved predictive human toxicity testing.

  13. Determining the Optimum Exposure and Recovery Periods for Efficient Operation of a QCM Based Elemental Mercury Vapor Sensor

    Directory of Open Access Journals (Sweden)

    K. M. Mohibul Kabir

    2015-01-01

    Full Text Available In recent years, mass based transducers such as quartz crystal microbalance (QCM have gained huge interest as potential sensors for online detection of elemental mercury (Hg0 vapor from anthropogenic sources due to their high portability and robust nature enabling them to withstand harsh industrial environments. In this study, we determined the optimal Hg0 exposure and recovery times of a QCM based sensor for ensuring its efficient operation while monitoring low concentrations of Hg0 vapor (<400 ppbv. The developed sensor was based on an AT-cut quartz substrate and utilized two gold (Au films on either side of the substrate which functions as the electrodes and selective layer simultaneously. Given the temporal response mechanisms associated with mass based mercury sensors, the experiments involved the variation of Hg0 vapor exposure periods while keeping the recovery time constant following each exposure and vice versa. The results indicated that an optimum exposure and recovery periods of 30 and 90 minutes, respectively, can be utilized to acquire the highest response magnitudes and recovery rate towards a certain concentration of Hg0 vapor whilst keeping the time it takes to report an accurate reading by the sensor to a minimum level as required in real-world applications.

  14. Mercury methylation in high and low-sulphate impacted wetland ponds within the prairie pothole region of North America

    International Nuclear Information System (INIS)

    Hoggarth, Cameron G.J.; Hall, Britt D.; Mitchell, Carl P.J.

    2015-01-01

    Using enriched stable 201 Hg injections into intact sediment cores, we provide the first reported Hg methylation potential rate constants (k m ) in prairie wetland ponds (0.016–0.17 d −1 ). Our k m values were similar to other freshwater wetlands and did not differ in ponds categorized with high compared to low surface water concentrations of sulphate. Sites with high sulphate had higher proportions of methylmercury (MeHg) in sediment (2.9 ± 1.6% vs. 1.0 ± 0.3%) and higher surface water MeHg concentrations (1.96 ± 1.90 ng L −1 vs. 0.56 ± 0.55 ng L −1 ). Sediment-porewater partitioning coefficients were small, and likely due to high ionic activity. Our work suggests while k m measurements are useful for understanding mercury cycling processes, they are less important than surface water MeHg concentrations for assessing MeHg risks to biota. Significant differences in MeHg concentrations between sites with high and low sulphate concentrations may also inform management decisions concerning wetland remediation and creation. - Highlights: • Wetlands of the PPR provide many vital ecosystem services, but can have high MeHg concentrations. • Methylation potentials in prairie ponds are similar to other freshwater wetlands. • MeHg and %MeHg in surface water of high sulphate ponds was greater than low sulphate ponds. • Sediment-porewater partitioning coefficients were small compared to other systems. • Potential methylation rate constants did not correlate to surface water concentrations. - Prairie wetland ponds with higher sulphate concentrations have greater sediment and surface water methylmercury concentrations, but potential methylation rates do not differ

  15. Effect of Gestational Intake of Fisetin (3,3',4',7-Tetrahydroxyflavone) on Developmental Methyl Mercury Neurotoxicity in F1 Generation Rats.

    Science.gov (United States)

    Jacob, Sherin; Thangarajan, Sumathi

    2017-06-01

    Methyl mercury (MeHg) is a developmental neurotoxin that causes irreversible cognitive damage in offspring of gestationally exposed mothers. Currently, no preventive drugs are established against MeHg developmental neurotoxicity. The neuroprotective effect of gestational administration of a flavanoid against in utero toxicity of MeHg is not explored much. Hence, the present study validated the effect of a bioactive flavanoid, fisetin, on MeHg developmental neurotoxicity outcomes in rat offspring at postnatal weaning age. Pregnant Wistar rats were simultaneously given MeHg (1.5 mg/kg b.w.) and two doses of fisetin (10 and 50 mg/kg b.w. in two separate groups) orally from gestational day (GD) 5 till parturition. Accordingly, after parturition, on postnatal day (PND) 24, weaning F 1 generation rats were studied for motor and cognitive behavioural changes. Biochemical and histopathological changes were also studied in the cerebral cortex, cerebellum and hippocampus on PND 25. Administration of fisetin during pregnancy prevented behavioural impairment due to transplacental MeHg exposure in weaning rats. Fisetin decreased the levels of oxidative stress markers, increased enzymatic and non-enzymatic antioxidant levels and increased the activity of membrane-bound ATPases and cholinergic function in F 1 generation rats. In light microscopic studies, fisetin treatment protected the specific offspring brain regions from significant morphological aberrations. Between the two doses of fisetin studied, 10 mg/kg b.w. was found to be more satisfactory and effective than 50 mg/kg b.w. The present study shows that intake of fisetin during pregnancy in rats ameliorated in utero MeHg exposure-induced neurotoxicity outcomes in postnatal weaning F 1 generation rats.

  16. Associations among oxytocin receptor gene (OXTR) DNA methylation in adulthood, exposure to early life adversity, and childhood trajectories of anxiousness.

    Science.gov (United States)

    Gouin, J P; Zhou, Q Q; Booij, L; Boivin, M; Côté, S M; Hébert, M; Ouellet-Morin, I; Szyf, M; Tremblay, R E; Turecki, G; Vitaro, F

    2017-08-07

    Recent models propose deoxyribonucleic acid methylation of key neuro-regulatory genes as a molecular mechanism underlying the increased risk of mental disorder associated with early life adversity (ELA). The goal of this study was to examine the association of ELA with oxytocin receptor gene (OXTR) methylation among young adults. Drawing from a 21-year longitudinal cohort, we compared adulthood OXTR methylation frequency of 46 adults (23 males and 23 females) selected for high or low ELA exposure based on childhood socioeconomic status and exposure to physical and sexual abuse during childhood and adolescence. Associations between OXTR methylation and teacher-rated childhood trajectories of anxiousness were also assessed. ELA exposure was associated with one significant CpG site in the first intron among females, but not among males. Similarly, childhood trajectories of anxiousness were related to one significant CpG site within the promoter region among females, but not among males. This study suggests that females might be more sensitive to the impact of ELA on OXTR methylation than males.

  17. Mercury exposure and risk of cardiovascular disease: a nested case-control study in the PREDIMED (PREvention with MEDiterranean Diet) study.

    Science.gov (United States)

    Downer, Mary K; Martínez-González, Miguel A; Gea, Alfredo; Stampfer, Meir; Warnberg, Julia; Ruiz-Canela, Miguel; Salas-Salvadó, Jordi; Corella, Dolores; Ros, Emilio; Fitó, Montse; Estruch, Ramon; Arós, Fernando; Fiol, Miquel; Lapetra, José; Serra-Majem, Lluís; Bullo, Monica; Sorli, Jose V; Muñoz, Miguel A; García-Rodriguez, Antonio; Gutierrez-Bedmar, Mario; Gómez-Gracia, Enrique

    2017-01-05

    Substantial evidence suggests that consuming 1-2 servings of fish per week, particularly oily fish (e.g., salmon, herring, sardines) is beneficial for cardiovascular health due to its high n-3 polyunsaturated fatty acid content. However, there is some concern that the mercury content in fish may increase cardiovascular disease risk, but this relationship remains unclear. The PREDIMED trial included 7477 participants who were at high risk for cardiovascular disease at baseline. In this study, we evaluated associations between mercury exposure, fish consumption and cardiovascular disease. We randomly selected 147 of the 288 cases diagnosed with cardiovascular disease during follow-up and matched them on age and sex to 267 controls. Instrumental neutron activation analysis was used to assess toenail mercury concentration. In-person interviews, medical record reviews and validated questionnaires were used to assess fish consumption and other covariates. Information was collected at baseline and updated yearly during follow-up. We used conditional logistic regression to evaluate associations in the total nested case-control study, and unconditional logistic regression for population subsets. Mean (±SD) toenail mercury concentrations (μg per gram) did not significantly differ between cases (0.63 (±0.53)) and controls (0.67 (±0.49)). Mercury concentration was not associated with cardiovascular disease in any analysis, and neither was fish consumption or n-3 fatty acids. The fully-adjusted relative risks for the highest versus lowest quartile of mercury concentration were 0.71 (95% Confidence Interval [CI], 0.34, 1.14; p trend  = 0.37) for the nested case-control study, 0.74 (95% CI, 0.32, 1.76; p trend  = 0.43) within the Mediterranean diet intervention group, and 0.50 (95% CI, 0.13, 1.96; p trend  = 0.41) within the control arm of the trial. Associations remained null when mercury was jointly assessed with fish consumption at baseline and during follow

  18. Mercury-induced motor and sensory neurotoxicity: systematic review of workers currently exposed to mercury vapor.

    Science.gov (United States)

    Fields, Cheryl A; Borak, Jonathan; Louis, Elan D

    2017-11-01

    The neurotoxicity of elemental mercury (Hg 0 ) is well-recognized, but it is uncertain whether and for how long neurotoxicity persists; among studies that evaluated previously exposed workers, only one examined workers during and also years after exposure ceased. The aim of this review is to document the type, frequency, and dose-relatedness of objective neurological effects in currently exposed mercury workers and thereby provide first approximations of the effects one would have expected in previously exposed workers evaluated during exposure. We systematically reviewed studies of neurotoxicity in currently exposed mercury workers identified by searching MEDLINE (1950-2015), government reports, textbook chapters, and references cited therein; dental cohorts were not included. Outcomes on physical examination (PE), neurobehavioral (NB) tests, and electrophysiological studies were extracted and evaluated for consistency and dose-relatedness. Forty-five eligible studies were identified, comprising over 3000 workers chronically exposed to a range of Hg 0 concentrations (0.002-1.7 mg/m 3 ). Effects that demonstrated consistency across studies and increased frequency across urine mercury levels (200 μg/L, while NB testing is more appropriate for those with lower U Hg levels. They also provide benchmarks to which findings in workers with historical exposure can be compared.

  19. Epigenome-wide meta-analysis of methylation in children related to prenatal NO2 air pollution exposure

    NARCIS (Netherlands)

    Gruzieva, O.; Xu, C.J.; Breton, C.V.; Annesi-Maesano, I.; Antó, J.M.; Auffray, C.; Ballereau, S.; Bellander, T.; Bousquet, J.; Bustamante, M.; Charles, M.A.; de Kluizenaar, Y.; Den Dekker, H.T.; Duijts, L.; Felix, J.F.; Gehring, U.; Guxens, M.; Jaddoe, V.V.W.; Jankipersadsing, S.A.; Merid, S.K.; Kere, J.; Kumar, A.; Lemonnier, N.; Lepeule, J.; Nystad, W.; Page, C.M.; Panasevich, S.; Postma, D.; Slama, R.; Sunyer, J.; Söderhäll, C.; Yao, J.; London, S.J.; Pershagen, G.; Koppelman, G.H.; Melén, E.

    2017-01-01

    Background: Prenatal exposure to air pollution is considered to be associated with adverse effects on child health. This may partly be mediated by mechanisms related to DNA methylation. Objectives: We investigated associations between exposure to air pollution, using nitrogen dioxide (NO2) as

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

    Energy Technology Data Exchange (ETDEWEB)

    Perez Catan, Soledad [Laboratorio de Analisis por Activacion Neutronica, Comision Nacional de Energia Atomica, Centro Atomico Bariloche, 8400 Bariloche (Argentina); Guevara, Sergio Ribeiro [Laboratorio de Analisis por Activacion Neutronica, Comision Nacional de Energia Atomica, Centro Atomico Bariloche, 8400 Bariloche (Argentina)], E-mail: ribeiro@cab.cnea.gov.ar; Marvin-DiPasquale, Mark [US Geological Survey, 345 Middlefield Rd./MS 480, Menlo Park, CA 94025 (United States); Magnavacca, Cecilia [Centro Atomico Ezeiza, Comision Nacional de Energia Atomica, Presbitero Gonzalez y Aragon No. 15, B1802AYA, Ezeiza, Buenos Aires (Argentina); Cohen, Isaac Marcos [Departamento de Ingenieria Quimica, Facultad Regional Buenos Aires, Universidad Tecnologica Nacional, Medrano 951 (C1179AAQ) Buenos Aires (Argentina); Arribere, Maria [Laboratorio de Analisis por Activacion Neutronica, Comision Nacional de Energia Atomica, Centro Atomico Bariloche, 8400 Bariloche (Argentina)

    2007-09-15

    Methodological considerations on the determination of benthic methyl-mercury (CH{sub 3}Hg) production potentials were investigated on lake sediment, using {sup 197}Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and {gamma}-irradiation. Flash freezing showed similar CH{sub 3}Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with {gamma}-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 {sup 197}Hg(II) carry-over in the organic extraction and/or [{sup 197}Hg]CH{sub 3}Hg produced via abiotic reactions. Two CH{sub 3}Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO{sub 4} 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.

  1. Kazakhstan In situ BioTransformation of Mercury ...

    Science.gov (United States)

    Our final international work on the biological decontamination of the mercury contamination of soils in the Northern outskirts of Pavlodar as a result of activity at the former PO “Khimprom” chemical plant is reported here. The plant produced chlorine and alkali from the 1970s into the 1990s using the electrolytic amalgam method entailing the use of massive amounts of mercury. Ground water became contaminated with Hg resulting in a plume 470 m wide, 1.9 km long, estimated to contain 2 million cubic meters of water. This plume could reach the River Irtysh, a source of drinking water for large cities in Kazakhstan and Russia. Significant amounts of mercuric compounds are deposited in the sediments of Lake Balkyldak, 1.5 km north of the factory. This lake occasionally received wastewater from the factory. Phase I of the PO “Kimprom” clean-up that isolated the major sources of mercury at the site was completed in 2004. However, significant amounts of mercury remain underground including groundwater contaminated with Hg in the form of HgCl2 with little to no elemental or methyl mercury (MeHg). Develop biotechnology strategies to mitigate mercury contamination in groundwater

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

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  3. Ancestral TCDD exposure promotes epigenetic transgenerational inheritance of imprinted gene Igf2: Methylation status and DNMTs

    International Nuclear Information System (INIS)

    Ma, Jing; Chen, Xi; Liu, Yanan; Xie, Qunhui; Sun, Yawen; Chen, Jingshan; Leng, Ling; Yan, Huan; Zhao, Bin; Tang, Naijun

    2015-01-01

    Ancestral TCDD exposure could induce epigenetic transgenerational phenotypes, which may be mediated in part by imprinted gene inheritance. The aim of our study was to evaluate the transgenerational effects of ancestral TCDD exposure on the imprinted gene insulin-like growth factor-2 (Igf2) in rat somatic tissue. TCDD was administered daily by oral gavage to groups of F0 pregnant SD rats at dose levels of 0 (control), 200 or 800 ng/kg bw during gestation day 8–14. Animal transgenerational model of ancestral exposure to TCDD was carefully built, avoiding sibling inbreeding. Hepatic Igf2 expression of the TCDD male progeny was decreased concomitantly with hepatic damage and increased activities of serum hepatic enzymes both in the F1 and F3 generation. Imprinted Control Region (ICR) of Igf2 manifested a hypermethylated pattern, whereas methylation status in the Differentially Methylated Region 2 (DMR2) showed a hypomethylated manner in the F1 generation. These epigenetic alterations in these two regions maintained similar trends in the F3 generation. Meanwhile, the expressions of DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) changed in a non-monotonic manner both in the F1 and F3 generation. This study provides evidence that ancestral TCDD exposure may promote epigenetic transgenerational alterations of imprinted gene Igf2 in adult somatic tissue. - Highlights: • Ancestral TCDD exposure induces epigenetic transgenerational inheritance. • Ancestral TCDD exposure affects methylation status in ICR and DMR2 region of Igf2. • DNMTs play a role in TCDD induced epigenetic transgenerational changes of Igf2.

  4. Ancestral TCDD exposure promotes epigenetic transgenerational inheritance of imprinted gene Igf2: Methylation status and DNMTs

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jing; Chen, Xi; Liu, Yanan [Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070 (China); Xie, Qunhui [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Sun, Yawen; Chen, Jingshan; Leng, Ling; Yan, Huan [Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070 (China); Zhao, Bin, E-mail: binzhao@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Tang, Naijun, E-mail: tangnaijun@tijmu.edu.cn [Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070 (China)

    2015-12-01

    Ancestral TCDD exposure could induce epigenetic transgenerational phenotypes, which may be mediated in part by imprinted gene inheritance. The aim of our study was to evaluate the transgenerational effects of ancestral TCDD exposure on the imprinted gene insulin-like growth factor-2 (Igf2) in rat somatic tissue. TCDD was administered daily by oral gavage to groups of F0 pregnant SD rats at dose levels of 0 (control), 200 or 800 ng/kg bw during gestation day 8–14. Animal transgenerational model of ancestral exposure to TCDD was carefully built, avoiding sibling inbreeding. Hepatic Igf2 expression of the TCDD male progeny was decreased concomitantly with hepatic damage and increased activities of serum hepatic enzymes both in the F1 and F3 generation. Imprinted Control Region (ICR) of Igf2 manifested a hypermethylated pattern, whereas methylation status in the Differentially Methylated Region 2 (DMR2) showed a hypomethylated manner in the F1 generation. These epigenetic alterations in these two regions maintained similar trends in the F3 generation. Meanwhile, the expressions of DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) changed in a non-monotonic manner both in the F1 and F3 generation. This study provides evidence that ancestral TCDD exposure may promote epigenetic transgenerational alterations of imprinted gene Igf2 in adult somatic tissue. - Highlights: • Ancestral TCDD exposure induces epigenetic transgenerational inheritance. • Ancestral TCDD exposure affects methylation status in ICR and DMR2 region of Igf2. • DNMTs play a role in TCDD induced epigenetic transgenerational changes of Igf2.

  5. [Genotoxic damage among artisanal and small-scale mining workers exposed to mercury].

    Science.gov (United States)

    Rosales-Rimache, Jaime A; Elizabeth Malca, Nancy; Alarcón, Jhonatan J; Chávez, Manuel; Gonzáles, Marco Antonio

    2013-01-01

    To determine the genotoxic damage among artisanal and small-scale mining workers exposed to mercury. Observational cross-sectional study which evaluated mercury-exposed workers (n=83), whose cells were collected by mouth swab for further staining, microscopic observance, micronuclei count, and other nuclear alterations. 24-hour urine was also collected for the determination of inorganic mercury. 68.7% of participants were male, the mean age being 43 ± 12,4 years (range: 16-76). The average time of occupational exposure to mercury was 12,1 ± 6,7 years, and the contact with mercury was 4,1 ± 3,6 kg per person per day. 93% of participants failed to wear personal protection gear while handling mercury. Results of biological monitoring showed that 17% of participants had concentrations of mercury in urine higher than 2,5 µg/L, this value being the detection limit of the measurement technique used. Results of the genotoxic evaluation evidenced that 15% of people with labor exposure to mercury presented micronuclei in mouth epithelial cells, and other indicators of nuclear alteration such as nucleoplasmic bridges, gemmation and binucleation were found, which are also considered genotoxic events associated to the exposure of physical or chemical risk agents. The finding of micronuclei in mouth epithelial cells reflects genotoxic damage associated to the labor exposure of mercury used in artisanal and small-scale mining activities.

  6. Environmental contamination of mercury from Hg-mining areas in Wuchuan, northeastern Guizhou, China

    International Nuclear Information System (INIS)

    Qiu Guangle; Feng Xinbin; Wang Shaofeng; Shang Lihai

    2006-01-01

    Total Hg and methyl-Hg were evaluated in mine wastes, soils, water, and vegetations from the Wuchuan Hg-mining areas, Guizhou, China. Mine wastes contain high total Hg concentrations, ranging from 79 to 710 μg g -1 , and methyl-Hg from 0.32 to 3.9 ng g -1 . Total Hg in soil samples range from 0.33 to 320 μg g -1 and methyl-Hg from 0.69 to 20 ng g -1 . Vegetations present a high average total Hg concentration of 260 ng g -1 , which greatly exceeds the maximum Hg concentration of 20 ng g -1 recommended by the Chinese National Standard Agency for food sources. The rice samples contain elevated methyl-Hg concentrations, ranging from 4.2 to 18 ng g -1 . Stream water collected from Hg-mining areas is also contaminated, containing Hg as high as 360 ng l -1 , and methyl-Hg reaches up to 5.7 ng l -1 . Data indicate heavy Hg-contaminations and significant conversion of methyl-Hg in the study areas. - Mercury mining activities in Wuchun, Guizhou, China have resulted in seriously mercury contamination to the local environment

  7. Environmental contamination of mercury from Hg-mining areas in Wuchuan, northeastern Guizhou, China

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Guangle [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 73 Guanshui Road, Guiyang, Guizhou 550002 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Feng Xinbin [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 73 Guanshui Road, Guiyang, Guizhou 550002 (China)]. E-mail: fengxinbin@vip.skleg.cn; Wang Shaofeng [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 73 Guanshui Road, Guiyang, Guizhou 550002 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Shang Lihai [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 73 Guanshui Road, Guiyang, Guizhou 550002 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China)

    2006-08-15

    Total Hg and methyl-Hg were evaluated in mine wastes, soils, water, and vegetations from the Wuchuan Hg-mining areas, Guizhou, China. Mine wastes contain high total Hg concentrations, ranging from 79 to 710 {mu}g g{sup -1}, and methyl-Hg from 0.32 to 3.9 ng g{sup -1}. Total Hg in soil samples range from 0.33 to 320 {mu}g g{sup -1} and methyl-Hg from 0.69 to 20 ng g{sup -1}. Vegetations present a high average total Hg concentration of 260 ng g{sup -1}, which greatly exceeds the maximum Hg concentration of 20 ng g{sup -1} recommended by the Chinese National Standard Agency for food sources. The rice samples contain elevated methyl-Hg concentrations, ranging from 4.2 to 18 ng g{sup -1}. Stream water collected from Hg-mining areas is also contaminated, containing Hg as high as 360 ng l{sup -1}, and methyl-Hg reaches up to 5.7 ng l{sup -1}. Data indicate heavy Hg-contaminations and significant conversion of methyl-Hg in the study areas. - Mercury mining activities in Wuchun, Guizhou, China have resulted in seriously mercury contamination to the local environment.

  8. Presence of mercury in natural gas

    International Nuclear Information System (INIS)

    Gijselman, P.B.

    1991-01-01

    This paper describes the occupational health programme used to ensure that NAM and contractor personnel of the Nederlandse Aardolie Mij (NAM) exposed to mercury, common in Dutch gas, are adequately protected through the correct use of Personal Protective Equipment (PPE), proper instruction and suitable work procedures. To avoid health damage due to mercury exposure during maintenance and shutdown activities the occupational health department of NAM set up a programme covering 3 activities: monitoring of atmospheric air; sampling of inspired air during work, and measurement of mercury excretion in urine of workers instruction of company and contractor personnel consultancy during preparation of work instructions. The monitoring program showed that, through correct use of PPE, staff do not exhibit mercury concentration levels exceeding the human toxicity limit (100 ug/g creatinine) even after exposure to mercury vapor concentrations above the TLV of 0.5 mg/m 3 . The correct use of PPE is a result of the instruction programme which also promotes increased awareness for personnel of the harmful effects of mercury. Finally, the provision of consultancy during the preparation of work instructions has contributed to various measures; for instance, staff wearing plastic (Viton) protective suits may not work longer than 2 hours continuously to avoid heat exhaustion

  9. Mercury uptake in vivo by normal and acatalasemic mice exposed to metallic mercury vapor (203Hg degrees) and injected with metallic mercury or mercuric chloride (203HgCl2)

    International Nuclear Information System (INIS)

    Ogata, M.; Kenmotsu, K.; Hirota, N.; Meguro, T.; Aikoh, H.

    1985-01-01

    Levels of mercury in the brain and liver of acatalasemic mice immediately following exposure to metallic mercury vapor or injection of metallic mercury were higher than those found in normal mice. Acatalasemic mice had decreased levels of mercury in the blood and kidneys when the levels were compared with those of normal mice, which indicated that catalase plays a role in oxidizing and taking up mercury. Thus, the brain/blood or liver/blood ratio of mercury concentration in acatalasemic mice was significantly higher than that of normal mice. These results suggest that metallic mercury in the blood easily passed through the blood-brain or blood-liver barrier. The levels of mercury distribution to the kidneys of normal and acatalasemic mice, 1 hr after injection of mercuric chloride solution, were higher than that of normal and acatalasemic mice, respectively, 1 hr after injection of metallic mercury

  10. Hair analysis as a useful procedure for detection of vapour exposure to chemical warfare agents: simulation of sulphur mustard with methyl salicylate.

    Science.gov (United States)

    Spiandore, Marie; Piram, Anne; Lacoste, Alexandre; Josse, Denis; Doumenq, Pierre

    2014-06-01

    Chemical warfare agents (CWA) are highly toxic compounds which have been produced to kill or hurt people during conflicts or terrorist attacks. Despite the fact that their use is strictly prohibited according to international convention, populations' exposure still recently occurred. Development of markers of exposure to CWA is necessary to distinguish exposed victims from unexposed ones. We present the first study of hair usage as passive sampler to assess contamination by chemicals in vapour form. This work presents more particularly the hair adsorption capacity for methyl salicylate used as a surrogate of the vesicant sulphur mustard. Chemical vapours toxicity through the respiratory route has historically been defined through Haber's law's concentration-time (Ct) product, and vapour exposure of hair to methyl salicylate was conducted with various times or doses of exposure in the range of incapacitating and lethal Ct products corresponding to sulphur mustard. Following exposure, extraction of methyl salicylate from hair was conducted by simple soaking in dichloromethane. Methyl salicylate could be detected on hair for vapour concentration corresponding to about one fifth of the sulphur mustard concentration that would kill 50% of exposed individuals (LCt50). The amount of methyl salicylate recovered from hair increased with time or dose of exposure. It showed a good correlation with the concentration-time product, suggesting that hair could be used like a passive sampler to assess vapour exposure to chemical compounds. It introduces great perspectives concerning the use of hair as a marker of exposure to CWA. Copyright © 2014 John Wiley & Sons, Ltd.

  11. Response of DNA, proteins, lipids and antioxidant enzymes as measure of toxicity to mercury exposures in green mussel Perna viridis

    Digital Repository Service at National Institute of Oceanography (India)

    Verlecar, X.N.; Jena, K.B.; Chainy, G.B.N.

    Studies on exposures of gills of green-lipped mussel Perna viridis to sublethal levels of mercury (Hg) indicates that oxidative stress marker like lipids peroxidation and protein carbonyl content increase. With the exception of superoxide dismutase...

  12. Future trends in environmental mercury concentrations: implications for prevention strategies

    Directory of Open Access Journals (Sweden)

    Sunderland Elsie M

    2013-01-01

    Full Text Available Abstract In their new paper, Bellanger and coauthors show substantial economic impacts to the EU from neurocognitive impairment associated with methylmercury (MeHg exposures. The main source of MeHg exposure is seafood consumption, including many marine species harvested from the global oceans. Fish, birds and other wildlife are also susceptible to the impacts of MeHg and already exceed toxicological thresholds in vulnerable regions like the Arctic. Most future emissions scenarios project a growth or stabilization of anthropogenic mercury releases relative to present-day levels. At these emissions levels, inputs of mercury to ecosystems are expected to increase substantially in the future, in part due to growth in the legacy reservoirs of mercury in oceanic and terrestrial ecosystems. Seawater mercury concentration trajectories in areas such as the North Pacific Ocean that supply large quantities of marine fish to the global seafood market are projected to increase by more than 50% by 2050. Fish mercury levels and subsequent human and biological exposures are likely to also increase because production of MeHg in ocean ecosystems is driven by the supply of available inorganic mercury, among other factors. Analyses that only consider changes in primary anthropogenic emissions are likely to underestimate the severity of future deposition and concentration increases associated with growth in mercury reservoirs in the land and ocean. We therefore recommend that future policy analyses consider the fully coupled interactions among short and long-lived reservoirs of mercury in the atmosphere, ocean, and terrestrial ecosystems. Aggressive anthropogenic emission reductions are needed to reduce MeHg exposures and associated health impacts on humans and wildlife and protect the integrity of one of the last wild-food sources globally. In the near-term, public health advice on safe fish consumption choices such as smaller species, younger fish, and harvests

  13. Mechanisms of Hg(II) uptake and methylation in methylating bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Morel, Francois M. M. [Princeton Univ., NJ (United States). Geosciences

    2016-10-14

    The goal of this project was to understand the critical factors which control the availability and transport of Hg(II) into cells, a first step in the production of the neurotoxin, methylmercury. Specifically, this research focused on understanding the mechanism of bacterial mercury uptake and how mercury speciation affects the specificity and kinetics of mercury transport. Our research has shown that Hg(II) uptake in three different iron and sulfate-reducing proteobacteria occurs by the following mechanism (1) : Hg(II) uptake is an active transport process requiring energy, (2) it is dependent upon the structure of the Hg binding ligand, and (3) it is mediated by a heavy metal transporter such as one which transports the essential metal, Zn(II). In order to determine whether this mechanism extends to more diverse phylogenetic groups, we have begun examining Hg(II) uptake and bioavailability in two representative Hg methylating strains within the Firmicutes. These organisms have remarkably different membrane structures distinct from the Proteobacteria. Our results show low uptake rates in these two species of Firmicutes relative to the previously characterized Proteobacteria. This may explain the low methylation rates and yields observed in these organisms. Most surprisingly, however, these organisms appear to take up Hg(II) passively, as the addition of a protonophore failed to reduce Hg(II) uptake in these organisms. This is quite different to what has been observed previously for the Proteobacteria and suggests a different mechanism for Hg(II) uptake in the Firmicutes. We are continuing to understand and describe Hg(II) uptake in these organisms. A manuscript is expected to be submitted on this research in June 2016.

  14. Pulmonary CT findings in acute mercury vapour exposure

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Manabu; Sato, Kimihiko; Heianna, Jyouiti; Hirano, Yoshinori; Omachi, Kohiti; Izumi, Jyunichi; Watarai, Jiro

    2001-01-01

    AIM: We describe the pulmonary computed tomography (CT) findings in acute mercury poisoning. MATERIALS AND METHODS: Initial (n= 8) and follow-up (n= 6) chest CT examinations in eight patients exposed to mercury vapour while cutting pipes in a sulphuric acid plant were reviewed. Of the eight patients, two were asymptomatic and had normal CT results, two were asymptomatic but had abnormalities on CT, and four had both acute symptoms and positive CT results. The patients were all men whose ages ranged from 37 to 54 years (mean, 49 years). RESULTS: Poorly defined nodules were present in five of six patients with positive CT findings, present alone in two patients or as part of a mixed pattern in three. They were random in distribution. Alveolar consolidation (n= 3) and areas of ground-glass opacity (n= 4) were observed and were more prominent in the most severely affected patients with the highest blood and urine level of mercury, predominantly in the upper and/or middle zone. These abnormal findings on CT resolved with (n= 1) or without (n= 5) steroid therapy. Pathological findings (n= 1) demonstrated acute interstitial changes predominantly with oedema. CONCLUSION: We report CT findings in eight patients acutely exposed to mercury vapour. The pulmonary injury was reversible on CT in these cases. Hashimoto, M. (2001)

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

    Science.gov (United States)

    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.

  16. Mercury contamination in fish and human hair from Hainan Island, South China Sea: Implication for human exposure.

    Science.gov (United States)

    Liu, Jin-Ling; Xu, Xiang-Rong; Yu, Shen; Cheng, Hefa; Peng, Jia-Xi; Hong, Yi-Guo; Feng, Xin-Bin

    2014-11-01

    Hair has long been recognized as a good biomarker for human exposure to Hg. The mercury concentrations in 14 species of marine fish and hair samples from 177 coastal residents in Hainan, South China Sea were investigated to assess the status of mercury exposure associated with marine fish consumption. Concentrations of total Hg (THg) and methylmercury (MeHg) in the fish muscles were 0.094 ± 0.008 and 0.066 ± 0.006 μg/gww, respectively, which were far below the limit considered safe for consumption (0.5 μg/g). The average THg concentrations in hair of adults (1.02 ± 0.92 μg/g) were lower than the provisional tolerable weekly intake (PTWI) level of 2.2 μg/g. However, 23.7% of children had a hair THg level exceeding the RfD level of 1μg/g, indicating a great risk of Hg exposure to children via fish consumption. The concentration of THg in hair was significantly correlated with fish consumption but not with gender-specific fish intake. With higher fish consumption frequency, the fishermen had significantly elevated hair Hg levels compared to the students and the other general public, who had similar hair THg levels but different fish consumption patterns, indicating the existence of other sources of Hg exposure to the residents of Hainan Island. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Overview of developmental, reproductive, and behavioral/ neurological effects of mercury exposures in wildlife

    Science.gov (United States)

    Heinz, G.H.; Hoffman, D.; Klimstra, J.; Stebbins, K.

    2007-01-01

    studies with mallards (Anas platyrhynchos) suggest that the dietary concentrations of mercury that cause toxicity are lower than those set in fish consumption advisories to protect humans. Because wild mammals and birds are so sensitive to methylmercury poisoning and cannot escape dietary exposure the way humans can, guidelines set to protect wild birds and mammals may very well provide a margin of safety for human health.

  18. Mercury-cycling in surface waters and in the atmosphere - species analysis for the investigation of transformation and transport properties of mercury

    International Nuclear Information System (INIS)

    Ebinghaus, R.; Hintelmann, H.; Wilken, R.D.

    1994-01-01

    The river Elbe has been one of the most contaminated rivers with regard to mercury for many years. In 1991 a length-profile has been measured for mercury and methylmercury (CH 3 Hg + ) from Obristvi, Czech Republic, to the German bight. Total mercury has been measured by cold vapor atomic absorption spectrometry (CVAAS). The organo mercury compounds have been separated by high performance liquid chromatography (HPLC) connected on-line to an atomic fluorescence spectrometer (AFS) by a continuous flow-system. Total mercury up to 120 mg Hg + /kg and CH 3 Hg + concentrations up to 130 μg CH 3 Hg + /kg could be detected in special sites. The formation of CH 3 Hg + in sediments can be caused besides the methylation of mercury, by sulphate reducing or methanogenic bacteria and transmethylation reactions with organometals. Atmospheric mercury concentrations have been measured at three different European sites. Samples have been collected on gold-coated glass balls or on quartz wool, respectively. After thermal desorption mercury has been determined using the two step amalgamation technique with AFS detection. Compared to natural background concentrations of total gaseous mercury (TGM), slightly increased levels could be detected at a rural site in Germany. This increase can probably be explained by long-range transport processes. Within the vicinity of a inactivated mercury production plant high concentrations of up to 13.5 ng/m 3 particle associated mercury (Hg part ) have been detected. Consequently, dry deposition of mercury in the particulate form can intensify the total deposition flux close to Hg-emitting sources. (orig.)

  19. The effect of mercury on baseline corticosterone in a breeding songbird.

    Science.gov (United States)

    Maddux, Sarah L; Cristol, Daniel A; Varian-Ramos, Claire W; Bradley, Eric L

    2015-02-01

    Although songbirds accumulate mercury at rates equivalent to better-studied aquatic avian species, effects of mercury bioaccumulation in songbirds remain understudied. Little is known about the effects of mercury on endocrine physiology, but recent evidence indicates that mercury may disrupt the function of the hypothalamic-pituitary-adrenal axis. Both field-based correlational studies and a recent dosing experiment suggest that mercury exposure alters levels of the primary avian stress hormone, CORT. We sampled zebra finches that had been dosed with 0, 0.5, or 1.0 ppm dietary methylmercury for baseline CORT twice; once during pairing and once after successfully fledging young. Circulating levels of CORT were not significantly affected by mercury exposure. However, our findings indicate potentially important differences in CORT responses between the sexes when exposed to environmentally relevant doses of mercury across the nesting cycle.

  20. Adolescent binge-pattern alcohol exposure alters genome-wide DNA methylation patterns in the hypothalamus of alcohol-naïve male offspring.

    Science.gov (United States)

    Asimes, AnnaDorothea; Torcaso, Audrey; Pinceti, Elena; Kim, Chun K; Zeleznik-Le, Nancy J; Pak, Toni R

    2017-05-01

    Teenage binge drinking is a major health concern in the United States, with 21% of teenagers reporting binge-pattern drinking behavior in the previous 30 days. Recently, our lab showed that alcohol-naïve offspring of rats exposed to alcohol during adolescence exhibited altered gene expression profiles in the hypothalamus, a brain region involved in stress regulation. We employed Enhanced Reduced Representation Bisulfite Sequencing as an unbiased approach to test the hypothesis that parental exposure to binge-pattern alcohol during adolescence alters DNA methylation profiles in their alcohol-naïve offspring. Wistar rats were administered a repeated binge-ethanol exposure paradigm during early (postnatal day (PND) 37-44) and late (PND 67-74) adolescent development. Animals were mated 24 h after the last ethanol dose and subsequent offspring were produced. Analysis of male PND7 offspring revealed that offspring of alcohol-exposed parents exhibited differential DNA methylation patterns in the hypothalamus. The differentially methylated cytosines (DMCs) were distinct between offspring depending on which parent was exposed to ethanol. Moreover, novel DMCs were observed when both parents were exposed to ethanol and many DMCs from single parent ethanol exposure were not recapitulated with dual parent exposure. We also measured mRNA expression of several differentially methylated genes and some, but not all, showed correlative changes in expression. Importantly, methylation was not a direct predictor of expression levels, underscoring the complexity of transcriptional regulation. Overall, we demonstrate that adolescent binge ethanol exposure causes altered genome-wide DNA methylation patterns in the hypothalamus of alcohol-naïve offspring. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Mercury in Nordic ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Munthe, John; Waengberg, Ingvar (IVL Swedish Environmental Research Inst., Stockholm (SE)); Rognerud, Sigurd; Fjeld, Eirik (Norwegian Inst. for Water Research (NIVA), Oslo (Norway)); Verta, Matti; Porvari, Petri (Finnish Environment Inst. (SYKE), Helsinki (Finland)); Meili, Markus (Inst. of Applied Environmental Research (ITM), Stockholm (Sweden))

    2007-12-15

    pollution effects (i.e. methylmercury in fish). The general pattern of fish contamination follows to some extent a pattern similar to that of current and previous atmospheric pollution. Large areas have fish with mercury concentrations exceeding the health advisory guideline of 0.5 mg/kg or 1.0 mg/kg (for northern pike) in the EU and of around 0.3 mg/kg in the USA, thus restricting their use for human consumption. A more comprehensive assessment of factors influencing levels of methylmercury in fish has to include a number of other parameters such as catchment characteristics (e.g. relative size, presence of wetlands), contents and fluxes of DOC in soil run-off and surface waters as well as methylation potential within ecosystems

  2. Mercury Toxicity and Treatment: A Review of the Literature

    Science.gov (United States)

    Bernhoft, Robin A.

    2012-01-01

    Mercury is a toxic heavy metal which is widely dispersed in nature. Most human exposure results from fish consumption or dental amalgam. Mercury occurs in several chemical forms, with complex pharmacokinetics. Mercury is capable of inducing a wide range of clinical presentations. Diagnosis of mercury toxicity can be challenging but can be obtained with reasonable reliability. Effective therapies for clinical toxicity have been described. PMID:22235210

  3. Mercury Toxicity and Treatment: A Review of the Literature

    Directory of Open Access Journals (Sweden)

    Robin A. Bernhoft

    2012-01-01

    Full Text Available Mercury is a toxic heavy metal which is widely dispersed in nature. Most human exposure results from fish consumption or dental amalgam. Mercury occurs in several chemical forms, with complex pharmacokinetics. Mercury is capable of inducing a wide range of clinical presentations. Diagnosis of mercury toxicity can be challenging but can be obtained with reasonable reliability. Effective therapies for clinical toxicity have been described.

  4. Biogeochemistry of mercury in contaminated environment in the wider Idrija region and the Gulf of Trieste

    International Nuclear Information System (INIS)

    Horvat, Milena; Jereb, Vesna; Fajon, Vesna; Lgar, Martina; Faganeli, Jadram; Hines, Mark

    2002-01-01

    During the reporting period work three main topics have been addressed in order to achieve the objectives of the CRP: 1. Methylmercury formation and degradation in sediments of the Gulf of Trieste. 2. Preparation of SOIL-1 intercomparison sample. 3. Validation of techniques for determination of the rates for methylation and demethylation of mercury in various matrices. The present report covers the first two topics, while the third is presented as a separate manuscript in this report, dealing with methylation of mercury in Isopod Porcellio scaber and in lichens. (author)

  5. Arsenic exposure from drinking water is associated with decreased gene expression and increased DNA methylation in peripheral blood

    Energy Technology Data Exchange (ETDEWEB)

    Ameer, Syeda Shegufta [Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund (Sweden); Engström, Karin [Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund (Sweden); Institute of Environmental Medicine, Unit of Metals & Health, Karolinska Institutet, Stockholm (Sweden); Hossain, Mohammad Bakhtiar [Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund (Sweden); Concha, Gabriela [Science Department, Risk Benefit Assessment Unit, National Food Agency, Uppsala (Sweden); Vahter, Marie [Institute of Environmental Medicine, Unit of Metals & Health, Karolinska Institutet, Stockholm (Sweden); Broberg, Karin, E-mail: Karin.broberg@ki.se [Institute of Environmental Medicine, Unit of Metals & Health, Karolinska Institutet, Stockholm (Sweden)

    2017-04-15

    Background: Exposure to inorganic arsenic increases the risk of cancer and non-malignant diseases. Inefficient arsenic metabolism is a marker for susceptibility to arsenic toxicity. Arsenic may alter gene expression, possibly by altering DNA methylation. Objectives: To elucidate the associations between arsenic exposure, gene expression, and DNA methylation in peripheral blood, and the modifying effects of arsenic metabolism. Methods: The study participants, women from the Andes, Argentina, were exposed to arsenic via drinking water. Arsenic exposure was assessed as the sum of arsenic metabolites in urine (U-As), using high performance liquid-chromatography hydride-generation inductively-coupled-plasma-mass-spectrometry, and arsenic metabolism efficiency was assessed by the urinary fractions (%) of the individual metabolites. Genome-wide gene expression (N = 80 women) and DNA methylation (N = 93; 80 overlapping with gene expression) in peripheral blood were measured using Illumina DirectHyb HumanHT-12 v4.0 and Infinium Human-Methylation 450K BeadChip, respectively. Results: U-As concentrations, ranging 10–1251 μg/L, was associated with decreased gene expression: 64% of the top 1000 differentially expressed genes were down-regulated with increasing U-As. U-As was also associated with hypermethylation: 87% of the top 1000 CpGs were hypermethylated with increasing U-As. The expression of six genes and six individual CpG sites were significantly associated with increased U-As concentration. Pathway analyses revealed enrichment of genes related to cell death and cancer. The pathways differed somewhat depending on arsenic metabolism efficiency. We found no overlap between arsenic-related gene expression and DNA methylation for individual genes. Conclusions: Increased arsenic exposure was associated with lower gene expression and hypermethylation in peripheral blood, but with no evident overlap. - Highlights: • Women exposed to inorganic arsenic were studied for

  6. Assessment of health risk of exposure to mercury through intake under canned tuna in health registration process period January 2010-December 2011

    International Nuclear Information System (INIS)

    Carrillo, M.; Tovar, M.; Alvarez, J.; Arraez, M.; Hordziejewicz, I.; Loreto, I.

    2013-01-01

    The power point presentation is about: Assessing the health risk due to exposure to mercury through ingestion canned tuna under sanitary registration process in the country, using the risk assessment tool recommended by the Codex Alimentarius establishing safety according to the use of local diets. The analytical method appied was Atomic Absorption Spectrophotometry Amalgamation (SS TDA AS). As a recommendation was important to maintain an ongoing program of monitoring of mercury in tuna as being a highly recommended food as being excellent source of protein and fatty acids beneficial to health can also be a source of mercury poisoning in cases of people who have a high consumption thereof in the diet

  7. Mercury-impacted scrap metal: Source and nature of the mercury.

    Science.gov (United States)

    Finster, Molly E; Raymond, Michelle R; Scofield, Marcienne A; Smith, Karen P

    2015-09-15

    The reuse and recycling of industrial solid wastes such as scrap metal is supported and encouraged both internationally and domestically, especially when such wastes can be used as substitutes for raw material. However, scrap metal processing facilities, such as mini-mills, have been identified as a source of mercury (Hg) emissions in the United States. This research aims to better define some of the key issues related to the source and nature of mercury in the scrap metal waste stream. Overall, it is difficult to pinpoint the key mercury sources feeding into scrap metal recycling facilities, quantify their associated mercury concentrations, or determine which chemical forms are most significant. Potential sources of mercury in scrap metal include mercury switches from discarded vehicles, electronic-based scrap from household appliances and related industrial systems, and Hg-impacted scrap metal from the oil and gas industry. The form of mercury associated with scrap metal varies and depends on the source type. The specific amount of mercury that can be adsorbed and retained by steel appears to be a function of both metallurgical and environmental factors. In general, the longer the steel is in contact with a fluid or condensate that contains measurable concentrations of elemental mercury, the greater the potential for mercury accumulation in that steel. Most mercury compounds are thermally unstable at elevated temperatures (i.e., above 350 °C). As such, the mercury associated with impacted scrap is expected to be volatilized out of the metal when it is heated during processing (e.g., shredding or torch cutting) or melted in a furnace. This release of fugitive gas (Hg vapor) and particulates, as well as Hg-impacted bag-house dust and control filters, could potentially pose an occupational exposure risk to workers at a scrap metal processing facility. Thus, identifying and characterizing the key sources of Hg-impacted scrap, and understanding the nature and extent

  8. Hair mercury levels in Amazonian populations: spatial distribution and trends

    Directory of Open Access Journals (Sweden)

    Barbieri Flavia L

    2009-12-01

    Full Text Available Abstract Background Mercury is present in the Amazonian aquatic environments from both natural and anthropogenic sources. As a consequence, many riverside populations are exposed to methylmercury, a highly toxic organic form of mercury, because of their intense fish consumption. Many studies have analysed this exposure from different approaches since the early nineties. This review aims to systematize the information in spatial distribution, comparing hair mercury levels by studied population and Amazonian river basin, looking for exposure trends. Methods The reviewed papers were selected from scientific databases and online libraries. We included studies with a direct measure of hair mercury concentrations in a sample size larger than 10 people, without considering the objectives, approach of the study or mercury speciation. The results are presented in tables and maps by river basin, displaying hair mercury levels and specifying the studied population and health impact, if any. Results The majority of the studies have been carried out in communities from the central Amazonian regions, particularly on the Tapajós River basin. The results seem quite variable; hair mercury means range from 1.1 to 34.2 μg/g. Most studies did not show any significant difference in hair mercury levels by gender or age. Overall, authors emphasized fish consumption frequency as the main risk factor of exposure. The most studied adverse health effect is by far the neurological performance, especially motricity. However, it is not possible to conclude on the relation between hair mercury levels and health impact in the Amazonian situation because of the relatively small number of studies. Conclusions Hair mercury levels in the Amazonian regions seem to be very heterogenic, depending on several factors. There is no obvious spatial trend and there are many areas that have never been studied. Taking into account the low mercury levels currently handled as acceptable, the

  9. Dietary human exposure to mercury in two artisanal small-scale gold mining communities of northwestern Colombia.

    Science.gov (United States)

    Salazar-Camacho, Carlos; Salas-Moreno, Manuel; Marrugo-Madrid, Siday; Marrugo-Negrete, José; Díez, Sergi

    2017-10-01

    Artisanal and small-scale gold mining (ASGM) is the largest anthropogenic source of mercury pollution worldwide, posing a grave threat to human health. The present study identifies current levels of mercury in the human population from mining areas of the Chocó Department, Colombia, through total mercury (THg) and methylmercury (MeHg) measurements in human hair. Mercury exposure of the local population was assessed in two towns affected by ASGM and was related to different variables of interest. Concentrations of THg in human hair ranged from 0.06 to 17.54ppm and the mean value for the subjects under study was 2.48ppm. Men had significantly higher levels than women in both towns (3.29ppm vs. 0.77ppm). Fish consumption was related to a marked increase of THg in hair, with mean values close to five times higher in frequent fish consumers (5-7 times/week) than in non-fish consumers (4.80ppm vs. 0.90ppm). A multiple linear regression model was fitted successfully (R=0.671) and reveals that gender, fish consumption and location of residence were significant indicators of Hg levels in hair, while no significant relationship was found for age. Approximately 60% of subjects tested had THg levels that exceeded the U.S. Environmental Protection Agency reference dose of 1.0ppm, while 25% surpassed that of the World Health Organization (2.2ppm). Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Influence of the forest canopy on total and methyl mercury deposition in the boreal forest

    Science.gov (United States)

    E.L. Witt; R.K. Kolka; E.A. Nater; T.R. Wickman

    2009-01-01

    Atmospheric mercury deposition by wet and dry processes contributes mercury to terrestrial and aquatic systems. Factors influencing the amount of mercury deposited to boreal forests were identified in this study. Throughfall and open canopy precipitation samples were collected in 2005 and 2006 using passive precipitation collectors from pristine sites located across...

  11. Mercury pollution in Malaysia.

    Science.gov (United States)

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

    2012-01-01

    Although several studies have been published on levels of mercury contamination of the environment, and of food and human tissues in Peninsular Malaysia, there is a serious dearth of research that has been performed in East Malaysia (Sabah and Sarawak). Industry is rapidly developing in East Malaysia, and, hence, there is a need for establishing baseline levels of mercury contamination in environmental media in that part of the country by performing monitoring studies. Residues of total mercury and inorganic in food samples have been determined in nearly all previous studies that have been conducted; however, few researchers have analyzed samples for the presence of methlymercury residues. Because methylmercury is the most toxic form of mercury, and because there is a growing public awareness of the risk posed by methylmercury exposure that is associated with fish and seafood consumption, further monitoring studies on methylmercury in food are also essential. From the results of previous studies, it is obvious that the economic development in Malaysia, in recent years, has affect