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Sample records for methylmercury tributyltin extreme

  1. Removal of methylmercury and tributyltin (TBT) using marine microorganisms.

    Science.gov (United States)

    Lee, Seong Eon; Chung, Jin Wook; Won, Ho Shik; Lee, Dong Sup; Lee, Yong-Woo

    2012-02-01

    Two marine species of bacteria were isolated that are capable of degrading organometallic contaminants: Pseudomonas balearica, which decomposes methylmercury; and Shewanella putrefaciens, which decomposes tributyltin. P. balearica decomposed 97% of methylmercury (20.0 μg/L) into inorganic mercury after 3 h, while S. putrefaciens decomposed 88% of tributyltin (55.3 μg Sn/L) in real wastewater after 36 h. These data indicate that the two bacteria efficiently decomposed the targeted substances and may be applied to real wastewater.

  2. Hematological findings in neotropical fish Hoplias malabaricus exposed to subchronic and dietary doses of methylmercury, inorganic lead, and tributyltin chloride

    International Nuclear Information System (INIS)

    Oliveira Ribeiro, C.A.; Filipak Neto, F.; Mela, M.; Silva, P.H.; Randi, M.A.F.; Rabitto, I.S.; Alves Costa, J.R.M.; Pelletier, E.

    2006-01-01

    Hematological indices are gaining general acceptance as valuable tools in monitoring various aspects the health of fish exposed to contaminants. In this work some effects of methyl mercury (MeHg), inorganic lead (Pb 2+ ), and tributyltin (TBT) in a tropical fish species were evaluated by hematological methods after a trophic exposition at a subchronic level. Forty-two mature individuals of the freshwater top predator fish Hoplias malabaricus were exposed to trophic doses (each 5 days) of MeHg (0.075 μg g -1 ), Pb 2+ (21 μg g -1 ), and TBT (0.3 μg g -1 ) using young fish Astyanax sp. as prey vehicle. After 14 successive doses over 70 days, blood was sampled from exposed and control groups to evaluate hematological effects of metals on erythrocytes, total leukocytes and differential leukocytes counts, hematocrit, hemoglobin concentration, and red blood cell indices mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). Transmission electron microscopy and image analysis of erythrocytes were also used to investigate some morphometric parameters. Results show no significant effects in MCH and MCHC for all tested metals, but differences were found in erythrocytes, hemoglobin, hematocrit, MCV, and white blood cells counts. The number of leukocytes was increased in the presence of MeHg, suggesting effects on the immune system. Also the MCV increased in individuals exposed to MeHg. No ultrastructural damages were observed in red blood cells but the image analysis using light microscopy revealed differences in area, elongation, and roundness of erythrocytes from individuals exposed to Pb 2+ and TBT but not in the group exposed to MeHg. The present work shows that changes in hematological and blood indices could highlight some barely detectable metal effects in fish after laboratory exposure to contaminated food, but their application in field biomonitoring using H. malabaricus will need more detailed

  3. Methylmercury and Pregnancy

    Science.gov (United States)

    ... exposed to methylmercury by eating fish, shellfish, and marine animals. These animals absorb methylmercury through the water in ... about all your breastfeeding questions. Is it a problem if the father of the baby is ... in experimental animals have shown that mercury can change the shape ...

  4. Aquatic Life Criteria - Tributyltin (TBT)

    Science.gov (United States)

    Documents pertaining to 2004 Final Acute and Chronic Ambient Aquatic Life Water Quality Criteria for Tributyltin (TBT) for freshwater and saltwater. These documents include the safe levels of TBT that should protect the majority of species.

  5. The obesogen tributyltin.

    Science.gov (United States)

    Grün, Felix

    2014-01-01

    The obesogen hypothesis postulates the role of environmental chemical pollutants that disrupt homeostatic controls and adaptive mechanisms to promote adipose-dependent weight gain leading to obesity and metabolic syndrome complications. One of the most direct molecular mechanisms for coupling environmental chemical exposures to perturbed physiology invokes pollutants mimicking endogenous endocrine hormones or bioactive dietary signaling metabolites that serve as nuclear receptor ligands. The organotin pollutant tributyltin can exert toxicity through multiple mechanisms but most recently has been shown to bind, activate, and mediate RXR-PPARγ transcriptional regulation central to lipid metabolism and adipocyte biology. Data in support of long-term obesogenic effects on whole body adipose tissue are also reported. Organotins represent an important model test system for evaluating the impact and epidemiological significance of chemical insults as contributing factors for obesity and human metabolic health. © 2014 Elsevier Inc. All rights reserved.

  6. Acute Toxicity of Tributyltins and Tributyltin Leachates from Marine Antibiofouling Paints.

    Science.gov (United States)

    1982-09-10

    RO-0184 224 ACUTE TOXICITY OF TRIBUTYLTINS AND TRIBUTYLTIN i/I LEACHATES FROM MARINE ANTIBIOFOULING PAINTS(U) CALIFORNIA UNIV OAKLAND NAVAL...Classification) (U) ACUTE TOXICITY OF TRIBUTYLTINS AND TRIBUTYLTIN LEACHATES FROM MARINE ANTIBIOFOULING PAINTS 12, PERSO A UHR Laugin, Koy"., Linden, Olof and...xins causing acute toxicity or two amphipou species at concentrations as low as 10 g/L . Orchestia traskiana was exposed to bis ( tributyltin ) oxide

  7. Highly selective determination of methylmercury with methylmercury-imprinted polymers

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yongwen [Department of Chemistry, Shanxi Datong University, Datong 037009 (China)]. E-mail: dtlyw@263.net; Zai Yunhui [School of Chemistry and Chemical Engineering of Lanzhou University, Lanzhou 730000 (China); Chang Xijun [School of Chemistry and Chemical Engineering of Lanzhou University, Lanzhou 730000 (China); Guo Yong [Department of Chemistry, Shanxi Datong University, Datong 037009 (China); Meng Shuangming [Department of Chemistry, Shanxi Datong University, Datong 037009 (China); Feng Feng [Department of Chemistry, Shanxi Datong University, Datong 037009 (China)

    2006-08-11

    Methylmercury-imprinted and non-imprinted polymers were prepared by formation monomer complex of methylmercury with (4-ethenylphenyl)-4-formate-6-phenyl-2,2'-bipyridine and thermally polymerizing with divinylbenzene (crosslinker) in the presence of 2,2'-azobisisobutyronitrile as initiator and subsequently leached with the acidic thiourea solution (1.0 mol L{sup -1} of thiourea and 4.0 mol L{sup -1} of HCl). In the same way, non-imprinted copolymers were prepared without methylmercury chloride added. The separation and preconcentration characteristics of the polymers for methylmercury were investigated by batch and column procedures. The results demonstrated that the methylmercury-imprinted polymers had higher adsorption capacity (170 {mu}mol g{sup -1} of dry microbeads) and good selectivity for methylmercury compared to non-imprinted polymers. The distribution ratio (D) values of the methylmercury-imprinted polymers increased for methylmercury with respect to both D values of Hg(II), Cu(II), Zn(II), Cd(II) and non-imprinted polymers. The relatively selective factor ({alpha} {sub r}) values of CH{sub 3}Hg{sup +}/Hg(II), CH{sub 3}Hg{sup +}/Cu(II), CH{sub 3}Hg{sup +}/Zn(II), and CH{sub 3}Hg{sup +}/Cd(II) are 24.0, 46.7, 50.7, and 40.2, which are greater than 1. The methylmercury-imprinted polymers can be used at least twenty times with recoveries no less than 95%. Based on the packed columns with methylmercury-imprinted polymers, a highly selective solid-phase extraction (SPE) and preconcentration method for methylmercury was developed. The metal ion imprinted polymer solid-phase extraction (MIIP-SPE) preconcentration procedure showed a linear calibration curve within concentration range from 0.093 to 22 {mu}g L{sup -1}. The detection limit and quantification limit were 0.041 and 0.093 {mu}g L{sup -1} (3{sigma}) for cold vapor atomic absorption spectrometry (CVAAS). The relative standard deviation of the 10 replicate determinations was 3.5% for the

  8. Minimum Release of Tributyltin to Prevent Macrofouling

    Science.gov (United States)

    1990-10-01

    Thain, J.E., M.J. Waldock, and M.E. Wait, Toxicity and degradation studies of Tributyltin ( TBT ) and Dibutyltin (DBT) in the aquatic environment, in...MATERIALS AND METHODS The test system used was designed to pump a known volume of a tributyltin ( TBT ) solution of known concentration through a porous...ELEMENT NO NO NO ACCESSION NO 11 TITLE (Include Security Classification) nimum Release of Tributyltin to Prevent Macrofoulinq 12 PERSONAL AUTHOR(S

  9. Radiochemical determination of methylmercury chloride Part 1

    International Nuclear Information System (INIS)

    Stary, J.; Prasilova, J.

    1976-01-01

    The isotope exchange between methylmercury species and an excess of inorganic radiomercury in sulphuric acid medium has been used for the simple determination of methylmercury chloride down to 0.01 ppm. The determination is not influenced by the presence of a great excess of other metals, however, chlorides, bromides and iodides interfere in higher concentrations. It has been found that the isotope exchange between CH 3 HgCl and 203 HgCl 4 2- (or 203 HgCl 2 ) in 0.01-3M hydrochloric acid is extremely slow, for the bimolecular reaction the rate constant is lower than 10 -3 mol -1 s -1 at 25 deg C. The isotope exchange rate between methylmercury chloride and mercuric-nitrate 0n on 0.5M sulphuric acid is higher. The isotope exchange is a bimolecular reaction with a rate constant k=0.050+-0.004 mol -1 s -1 at 25 deg C. (T.I.)

  10. Neurophysiological evidence of methylmercury neurotoxicity

    DEFF Research Database (Denmark)

    Murata, Katsuyuki; Grandjean, Philippe; Dakeishi, Miwako

    2007-01-01

    neurotoxicity and to examine the usefulness of those measures. METHODS: The reports addressing both neurophysiological measures and methylmercury exposure in humans were identified and evaluated. RESULTS: The neurological signs and symptoms of MD included paresthesias, constriction of visual fields, impairment...... disease (MD; methylmercury poisoning). In recent years, some of these methods have been used for the risk assessment of low-level methylmercury exposure in asymptomatic children. The objectives of this article were to present an overview of neurophysiological findings involved in methylmercury...... of hearing and speech, mental disturbances, excessive sweating, and hypersalivation. Neuropathological lesions involved visual, auditory, and post- and pre-central cortex areas. Neurophysiological changes involved in methylmercury, as assessed by EPs and HRV, were found to be in accordance with both clinical...

  11. Methylmercury toxicity and functional programming.

    Science.gov (United States)

    Grandjean, Philippe

    2007-01-01

    Adverse health effects of developmental toxicants may induce abnormal functional programming that leads to lasting functional deficits. This notion is considered from epidemiological evidence using developmental methylmercury neurotoxicity as an example. Accumulating evidence indicates that adverse effects may occur even at low-level methylmercury exposures from seafood and freshwater fish. Neurobehavioral outcomes are usually non-specific, and imprecise exposure assessment results in a bias toward the null. Essential nutrients may promote the development of certain brain functions, thereby causing confounding bias. The functional deficits caused by prenatal methylmercury exposure appear to be permanent, and their extent may depend on the joint effect of toxicants and nutrients. The lasting functional changes caused by neurodevelopmental methylmercury toxicity fit into the pattern of functional programming, with effects opposite to those linked to beneficial stimuli.

  12. Treatability Studies of Tributyltin in Activated Sludge

    Science.gov (United States)

    1989-12-01

    per liter pg/L Picograms per liter ppb Parts per billion RREL Risk Reduction Engineering Laboratory TBT Tributyltin Chloride TKN Total Kjeldahl number...success of tributyltin ( TBT ) compounds in inhibiting the growth of marine organisms has led to their use as pesticides in marine antifouling paints...organotin wastes because: (1) substan- tial dilution is available, which minimizes the toxic impacts of TBT compounds; (2) a diverse biomass is present, which

  13. Methylmercury toxicity and functional programming

    DEFF Research Database (Denmark)

    Grandjean, Philippe

    2007-01-01

    : Accumulating evidence indicates that adverse effects may occur even at low-level methylmercury exposures from seafood and freshwater fish. Neurobehavioral outcomes are usually non-specific, and imprecise exposure assessment results in a bias toward the null. Essential nutrients may promote the development......PURPOSE: Adverse health effects of developmental toxicants may induce abnormal functional programming that leads to lasting functional deficits. This notion is considered from epidemiological evidence using developmental methylmercury neurotoxicity as an example. MOST IMPORTANT FINDINGS...... of certain brain functions, thereby causing confounding bias. The functional deficits caused by prenatal methylmercury exposure appear to be permanent, and their extent may depend on the joint effect of toxicants and nutrients. PRINCIPAL CONCLUSIONS: The lasting functional changes caused...

  14. Adsorption of tributyltin by tributyltin resistant marine Pseudoalteromonas sp. cells

    International Nuclear Information System (INIS)

    Mimura, Haruo; Sato, Ryusei; Furuyama, Yuichi; Taniike, Akira; Yagi, Masahiro; Yoshida, Kazutoshi; Kitamura, Akira

    2008-01-01

    The isolate, Pesudoalteromonas sp. TBT1, could grow to overcome the toxicity of tributyltin chloride (TBTCl) up to 30 μM in the absence of Cl - in the medium until the cells reached an exponential phase of growth. The viability, however, was reduced after the cells reached a stationary phase. The degradation products, such as dibutyltin (DBT) and monobutyltin (MBT), were not detected in the growth medium, indicating that the isolate has no ability to degrade TBT into less toxic DBT and MBT. Up to about 10 7.5 TBT molecules were adsorbed by a single cell. The observation of morphological changes with an electron microscope showed that the cell surface became wrinkled after exposure to the lethal concentration of 10 mM TBTCl. These results indicate that the resistance of the isolate toward the toxicity of TBTCl is not related to the unique cell surface, which seems to play an important role in preventing the diffusion of TBTCl into the cytoplasm

  15. Adsorption of tributyltin by tributyltin resistant marine Pseudoalteromonas sp. cells

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, Haruo [Graduate School of Maritime Sciences, Kobe University, 5-1-1, Fukae, Higashinada, Kobe 658-0022 (Japan)], E-mail: hmimura@maritime.kobe-u.ac.jp; Sato, Ryusei; Furuyama, Yuichi; Taniike, Akira [Graduate School of Maritime Sciences, Kobe University, 5-1-1, Fukae, Higashinada, Kobe 658-0022 (Japan); Yagi, Masahiro [Department of Environmental Chemistry, Kobe Institute of Health, 4-6, Minatojima, Chuo, Kobe 650-0046 (Japan); Yoshida, Kazutoshi [Hyogo Prefectural Institute of Technology, 3-1-12, Yukihira, Suma, Kobe 654-0037 (Japan); Kitamura, Akira [Graduate School of Maritime Sciences, Kobe University, 5-1-1, Fukae, Higashinada, Kobe 658-0022 (Japan)

    2008-07-01

    The isolate, Pesudoalteromonas sp. TBT1, could grow to overcome the toxicity of tributyltin chloride (TBTCl) up to 30 {mu}M in the absence of Cl{sup -} in the medium until the cells reached an exponential phase of growth. The viability, however, was reduced after the cells reached a stationary phase. The degradation products, such as dibutyltin (DBT) and monobutyltin (MBT), were not detected in the growth medium, indicating that the isolate has no ability to degrade TBT into less toxic DBT and MBT. Up to about 10{sup 7.5} TBT molecules were adsorbed by a single cell. The observation of morphological changes with an electron microscope showed that the cell surface became wrinkled after exposure to the lethal concentration of 10 mM TBTCl. These results indicate that the resistance of the isolate toward the toxicity of TBTCl is not related to the unique cell surface, which seems to play an important role in preventing the diffusion of TBTCl into the cytoplasm.

  16. Metal accumulation in marine bivalves under various tributyltin burdens.

    Science.gov (United States)

    Tang, Chuan-Ho; Lin, Chan-Shing; Wang, Wei-Hsien

    2009-11-01

    In the present study, a field survey was conducted to measure the accumulation of butyltin, Cu, Zn, and Cd in green mussels (Perna viridis) and Pacific oysters (Crassostrea gigas) at the regions along a tributyltin pollution gradient. A negative correlation was found between the tributyltin/total butyltin ratio (0.87-0.31) and tributyltin content (114-5,817 ng/g as tin dry wt) in oysters, while the Cu content (44.2-381 mg/kg dry wt) was positively correlated with the logarithm of tributyltin content during the summer and winter. This suggests that as the tributyltin burden increases, the rates of tributyltin metabolism may be elevated, leading to enhanced Cu accumulation. A similar accumulation pattern for Zn was also found in oysters. In mussels, however, the tributyltin/total butyltin ratio and the Cu and Zn contents remained relatively constant (~ 0.7, 12, and 100 mg/kg dry wt, respectively) regardless of the tributyltin burden. Clearly, the butyltin and Cu/Zn accumulation processes in oysters differ from those in mussels under tributyltin pollution. These observations provide valuable information for those who evaluate or compare tributyltin and/or Cu/Zn pollution using oysters and mussels as bioindicators.

  17. Radiochemical determination of methylmercury in fish

    International Nuclear Information System (INIS)

    Stary, J.; Prasilova, J.; Kratzer, K.

    1978-01-01

    A selective and sensitive method for the determination of methylmercury has been developed. This method is based on the extraction of methylmercury chloride into benzene and on the subsequent exchange reaction with potassium iodide-131 solution. The previously developed method has been adapted for the analysis of fish. The content of methylmercury in frozen cod (Tenegra chalcograma), frozen marena (Coregonus lavaretus) and in fresh carp (Cyprinus carpio) has been compared with the total content of mercury determined by cold vapor spectrometry. (T.I.)

  18. Determination of methylmercury compounds in foodstuffs. II. Determination of methylmercury in fish, egg, meat, and liver

    Energy Technology Data Exchange (ETDEWEB)

    Westoeoe, G

    1967-01-01

    The combined gas chromatographic and thin-layer chromatographic method for the identification and determination of methylmercury compounds in fish (Westoeoe) has been modified in order to render it applicable to a wider range of foods. In animal foodstuffs methylmercury is probably to a great extent attached to thiol groups. When these foods are extracted according to Gage, methylmercury chloride is formed and dissolves in the benzene together with varying amounts of thio compounds. Purification of the methylmercury in the benzene extracts of e.g., egg yolk or liver by extraction with aqueous alkali solution did not work, probably because the thio compounds were not volatile and could form alkali-insoluble methylmercury salts. Evidently methylmercury-S-compounds were reformed at high pH and prevented the formation of the water-soluble methylmercury hydroxide. Addition of excess mercuric ions, which expelled the methylmercury from the thio compounds, solved this clean-up problem. Samples of fish, egg-white, egg yolk, meat, and liver have been analyzed with the modified method. Extraction of the methylmercury into an aqueous phase was also possible with the aid of a water solution of cysteine. This led to a more rapid analytical procedure. 8 references, 2 figures, 4 tables.

  19. Mechanism of immunotoxicological effects of tributyltin chloride on murine thymocytes.

    Science.gov (United States)

    Sharma, Neelima; Kumar, Anoop

    2014-04-01

    Tributyltin-chloride, a well-known organotin compound, is a widespread environmental toxicant. The immunotoxic effects of tributyltin-chloride on mammalian system and its mechanism is still unclear. This study is designed to explore the mode of action of tributyltin-induced apoptosis and other parallel apoptotic pathways in murine thymocytes. The earliest response in oxidative stress followed by mitochondrial membrane depolarization and caspase-3 activation has been observed. Pre-treatment with N-acetyl cysteine and buthionine sulfoximine effectively inhibited the tributyltin-induced apoptotic DNA and elevated the sub G1 population, respectively. Caspase inhibitors pretreatment prevent tributyltin-induced apoptosis. Western blot and flow cytometry indicate no translocation of apoptosis-inducing factor and endonuclease G in the nuclear fraction from mitochondria. Intracellular Ca(2+) levels are significantly raised by tributyltin chloride. These results clearly demonstrate caspase-dependent apoptotic pathway and support the role of oxidative stress, mitochondrial membrane depolarization, caspase-3 activation, and calcium during tributyltin-chloride (TBTC)-induced thymic apoptosis.

  20. Tributyltin synergizes with 20-hydroxyecdysone to produce endocrine toxicity.

    Science.gov (United States)

    Wang, Ying H; Kwon, Gwijun; Li, Hong; Leblanc, Gerald A

    2011-09-01

    One of the great challenges facing modern toxicology is in predicting the hazard associated with chemical mixtures. The development of effective means of predicting the toxicity of chemical mixtures requires an understanding of how chemicals interact to produce nonadditive outcomes (e.g., synergy). We hypothesized that tributyltin would elicit toxicity in daphnids (Daphnia magna) by exaggerating physiological responses to 20-hydroxyecdysone signaling via synergistic activation of the retinoid X receptor (RXR):ecdysteroid receptor (EcR) complex. Using reporter gene assays, we demonstrated that RXR, alone, is activated by a variety of ligands including tributyltin, whereas RXR:EcR heterodimers were not activated by tributyltin. However, tributyltin, in combination with the daphnid EcR ligand 20-hydroxyecdysone, caused concentration-dependent, synergistic activation of the RXR:EcR reporter. Electrophoretic mobility shift assays revealed that tributyltin did not enhance the activity of 20-hydroxyecdysone by increasing binding of the receptor complex to a DR-4 DNA-binding site. Exposure of daphnids to elevated concentrations of 20-hydroxyecdysone caused premature and incomplete ecdysis resulting in death. Tributyltin exaggerated this effect of exogenous 20-hydroxyecdysone. Further, exposure of daphnids to tributyltin enhanced the inductive effects of 20-hydroxyecdysone on expression of the 20-hydroxyecdysone-inducible gene HR3. Continuous, prolonged exposure of maternal daphnids to concentrations of tributyltin resulted in mortality concurrent with molting. Taken together, these results demonstrate that xenobiotics, such as tributyltin, can interact with RXR to influence gene expression regulated by the heterodimeric partner to RXR. The result of such interactions can be toxicity due to inappropriate or exaggerated hormonal signaling. The application of the in vitro/in vivo approach used in this study is discussed in relation to modeling of nonadditive interactions

  1. Potential sources of methylmercury in tree foliage

    International Nuclear Information System (INIS)

    Tabatchnick, Melissa D.; Nogaro, Géraldine; Hammerschmidt, Chad R.

    2012-01-01

    Litterfall is a major source of mercury (Hg) and toxic methylmercury (MeHg) to forest soils and influences exposures of wildlife in terrestrial and aquatic ecosystems. However, the origin of MeHg associated with tree foliage is largely unknown. We tested the hypothesis that leaf MeHg is influenced by root uptake and thereby related to MeHg levels in soils. Concentrations of MeHg and total Hg in deciduous and coniferous foliage were unrelated to those in soil at 30 urban and rural forested locations in southwest Ohio. In contrast, tree genera and trunk diameter were significant variables influencing Hg in leaves. The fraction of total Hg as MeHg averaged 0.4% and did not differ among tree genera. Given that uptake of atmospheric Hg 0 appears to be the dominant source of total Hg in foliage, we infer that MeHg is formed by in vivo transformation of Hg in proportion to the amount accumulated. - Highlights: ► Levels of methylmercury and total Hg in foliage were unrelated to those in soil. ► Methylmercury:total Hg ratio in leaves did not differ among nine tree genera. ► Hg in foliage varied inversely with trunk diameter, a proxy for respiration. ► Methylmercury in leaves may result from in vivo methylation of atmospheric Hg. - Methylmercury in tree foliage appears to result from in vivo methylation of mercury accumulated from the atmosphere.

  2. Distribution of tributyltin (TBT) in the Mandovi estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.

    . Their use as components of antifouling paints has increased several folds for the last few decades. The ship hulls coated with organotin such as tributyltin (TBT) reduce the attachment of marine organisms onto the ship hulls. Although organotins serve...

  3. Imposex incidence in Stramonita haemastoma (Gastropoda: Muricidae) from the Mediterranean and Atlantic coast after Tributyltin global ban

    Science.gov (United States)

    El Ayari, Tahani; Bierne, Nicolas; El Menif, Najoua Trigui

    2018-04-01

    The development of male genital tract by female gastropods, or imposex, can be caused by the tributyltin used in antifouling paints. A spatial survey of imposex in the gastropod Stramonita haemastoma was conducted across five Western Mediterranean and eleven North-Eastern Atlantic sites, in order to monitor the effectiveness of the tributyltin regulation imposed in the International Maritime Organisation. Imposex still occurs in eight out of eleven Mediterranean sites and in three out of five Atlantic sites. Extreme values of imposex incidence (I%) and degree (VDSI) were recorded in Tunisia, mainly in Bizerta channel (I% = 96.2%, VDSI = 0.96). However, the Relative Penis Length index (RPLI) was higher in Western Mediterranean sites where values varied between 0.56 in Algiers (Algeria) and 11.80 in Bouznika (Morocco). In the European sites, moderate to low imposex level and degree were recorded. All the affected sites were below the Ecotoxicological Assessment Criteria (EAC) derived for TBT.

  4. IRIS Summary and Supporting Documents for Methylmercury ...

    Science.gov (United States)

    In January 2001, U.S. EPA finalized the guidance for methylmercury in the water quality criteria for states and authorized tribes. The links below take you to the best resources for this guidance. This final Guidance for Implementing the January 2001 Methylmercury Water Quality Criterion provides technical guidance to states and authorized tribes on how they may want to use the January 2001 fish tissue-based recommended water quality criterion for methylmercury in surface water protection programs (e.g., TMDLs, NPDES permitting). The guidance addresses questions related to water quality standards adoption (e.g., site-specific criteria, variances), assessments, monitoring, TMDLs, and NPDES permitting. The guidance consolidates existing EPA guidance where relevant to mercury.

  5. Trace-elements, methylmercury and metallothionein levels in Magellanic penguin (Spheniscus magellanicus) found stranded on the Southern Brazilian coast.

    Science.gov (United States)

    Kehrig, Helena A; Hauser-Davis, Rachel A; Seixas, Tércia G; Fillmann, Gilberto

    2015-07-15

    Magellanic penguins have been reported as good biomonitors for several types of pollutants, including trace-elements. In this context, selenium (Se), total mercury, methylmercury, inorganic mercury (Hg(inorg)), cadmium (Cd) and lead (Pb), as well as metallothionein (MT) levels, were evaluated in the feathers, liver and kidney of juvenile Magellanic penguins found stranded along the coast of Southern Brazil. The highest concentrations of all trace-elements and methylmercury were found in internal organs. Concentrations of Cd and Se in feathers were extremely low in comparison with their concentrations in soft tissues. The results showed that both Se and MT are involved in the detoxification of trace-elements (Cd, Pb and Hg(inorg)) since statistically significant relationships were found in liver. Conversely, hepatic Se was shown to be the only detoxifying agent for methylmercury. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. THE BIOCIDE TRIBUTYLTIN ALTERS TESTOSTERONE ESTERIFICATION IN MUD SNAILS (ILYANASSA OBSOLETA)

    Science.gov (United States)

    The Biocide Tributyltin Alters Testosterone Esterification in Mud Snails (Ilyanassa obsoleta)Meredith P. Gooding and Gerald A. LeBlanc Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695-7633Tributyltin (TBT...

  7. Tributyltin and Zebrafish: Swimming in Dangerous Water

    Directory of Open Access Journals (Sweden)

    Clemilson Berto-Júnior

    2018-04-01

    Full Text Available Zebrafish has been established as a reliable biological model with important insertion in academy (morphologic, biochemical, and pathophysiological studies and pharmaceutical industry (toxicology and drug development due to its molecular complexity and similar systems biology that recapitulate those from other organisms. Considering the toxicological aspects, many efforts using zebrafish models are being done in order to elucidate the effects of endocrine disruptors, and some of them are focused on tributyltin (TBT and its mechanism of action. TBT is an antifouling agent applied in ship’s hull that is constantly released into the water and absorbed by marine organisms, leading to bioaccumulation and biomagnification effects. Thus, several findings of malformations and changes in the normal biochemical and physiologic aspects of these marine animals have been related to TBT contamination. In the present review, we have compiled the most significant studies related to TBT effects in zebrafish, also taking into consideration the effects found in other study models.

  8. Tributyltin and Zebrafish: Swimming in Dangerous Water

    Science.gov (United States)

    Berto-Júnior, Clemilson; de Carvalho, Denise Pires; Soares, Paula; Miranda-Alves, Leandro

    2018-01-01

    Zebrafish has been established as a reliable biological model with important insertion in academy (morphologic, biochemical, and pathophysiological studies) and pharmaceutical industry (toxicology and drug development) due to its molecular complexity and similar systems biology that recapitulate those from other organisms. Considering the toxicological aspects, many efforts using zebrafish models are being done in order to elucidate the effects of endocrine disruptors, and some of them are focused on tributyltin (TBT) and its mechanism of action. TBT is an antifouling agent applied in ship’s hull that is constantly released into the water and absorbed by marine organisms, leading to bioaccumulation and biomagnification effects. Thus, several findings of malformations and changes in the normal biochemical and physiologic aspects of these marine animals have been related to TBT contamination. In the present review, we have compiled the most significant studies related to TBT effects in zebrafish, also taking into consideration the effects found in other study models. PMID:29692757

  9. Accelerator Analysis of Tributyltin Adsorbed onto the Surface of a Tributyltin Resistant Marine Pseudoalteromonas sp. Cell

    OpenAIRE

    Mimura, Haruo; Sato, Ryusei; Sasaki, Yu; Furuyama, Yuichi; Taniike, Akira; Yoshida, Kazutoshi; Kitamura, Akira

    2008-01-01

    Tributyltin (TBT) released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship’s ballast water. The isolate (109.3 ± 0.2 colony-forming units mL-1) adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 108.2. The value was reduced to about one-fif...

  10. Stimulation of estradiol biosynthesis by tributyltin in rat hippocampal slices.

    Science.gov (United States)

    Munetsuna, Eiji; Hattori, Minoru; Yamazaki, Takeshi

    2014-01-01

    Hippocampal functions are influenced by steroid hormones, such as testosterone and estradiol. It has been demonstrated that hippocampus-derived steroid hormones play important roles in neuronal protection and synapse formation. Our research groups have demonstrated that estradiol is de novo synthesized in the rat hippocampus. However, the mechanism(s) regulating this synthesis remains unclear. It has been reported that tributyltin, an environmental pollutant, binds to the retinoid X receptor (RXR) and modifies estrogen synthesis in human granulosa-like tumor cells. This compound can penetrate the blood brain barrier, and tends to accumulate in the brain. Based on these facts, we hypothesized that tributyltin could influence the hippocampal estradiol synthesis. A concentration of 0.1 μM tributyltin induced an increase in the mRNA content of P450(17α) and P450arom in hippocampal slices, as determined using real-time PCR. The transcript levels of other steroidogenic enzymes and a steroidogenic acute regulatory protein were not affected. The estradiol level in rat hippocampal slices was subsequently determined using a radioimmunoassay. We found that the estradiol synthesis was stimulated by ∼2-fold following a 48-h treatment with 0.1 μM tributyltin, and this was accompanied by transcriptional activation of P450(17α) and P450arom. Tributyltin stimulated de novo hippocampal estradiol synthesis by modifying the transcription of specific steroidogenic enzymes.

  11. Tributyltin interacts with mitochondria and induces cytochrome c release.

    Science.gov (United States)

    Nishikimi, A; Kira, Y; Kasahara, E; Sato, E F; Kanno, T; Utsumi, K; Inoue, M

    2001-01-01

    Although triorganotins are potent inducers of apoptosis in various cell types, the critical targets of these compounds and the mechanisms by which they lead to cell death remain to be elucidated. There are two major pathways by which apoptotic cell death occurs: one is triggered by a cytokine mediator and the other is by a mitochondrion-dependent mechanism. To elucidate the mechanism of triorganotin-induced apoptosis, we studied the effect of tributyltin on mitochondrial function. We found that moderately low doses of tributyltin decrease mitochondrial membrane potential and induce cytochrome c release by a mechanism inhibited by cyclosporine A and bongkrekic acid. Tributyltin-induced cytochrome c release is also prevented by dithiols such as dithiothreitol and 2,3-dimercaptopropanol but not by monothiols such as GSH, N-acetyl-L-cysteine, L-cysteine and 2-mercaptoethanol. Further studies with phenylarsine oxide agarose revealed that tributyltin interacts with the adenine nucleotide translocator, a functional constituent of the mitochondrial permeability transition pore, which is selectively inhibited by dithiothreitol. These results suggest that, at low doses, tributyltin interacts selectively with critical thiol residues in the adenine nucleotide translocator and opens the permeability transition pore, thereby decreasing membrane potential and releasing cytochrome c from mitochondria, a series of events consistent with established mechanistic models of apoptosis. PMID:11368793

  12. Degradation of tributyltin in San Diego Bay, California, waters

    International Nuclear Information System (INIS)

    Seligman, P.F.; Valkirs, A.O.; Lee, R.F.

    1986-01-01

    Several experiments were carried out to determine the degradation rate of tributyltin (TBT) in microcosms containing harbor water. Unlabeled or 14 C-labeled tributyltin was added to water samples collected from two stations in San Diego Bay, CA. Degradation rates were determined by calculating the rate of loss of the added parent TBT compound. Calculated half-lives in water collected from a yacht harbor (ambient concentration was 0.5 μg of TBT/L) were 6 and 7 days for light and dark treatments, respectively. Half-lives from a clean-water site ( 14 CO 2 , proceeded slowly with a half-life of 50-75 days. Tributyltin at high concentrations (744 μg/L) was not degraded in sunlight, indicating that photolysis was not taking place and that biological degradation was the primary degradative process for TBT at low ambient concentrations

  13. Biodegradation of Tributyltin (TBT) by Extremophile Bacteria from Atacama Desert and Speciation of Tin By-products.

    Science.gov (United States)

    Yáñez, Jorge; Riffo, Paula; Santander, Paola; Mansilla, Héctor D; Mondaca, María Angélica; Campos, Víctor; Amarasiriwardena, Dulasiri

    2015-07-01

    Biodegradation of tributyltin (TBT) by four tin resistant Gram negative bacteria isolated from extremely contaminated river sediments in the Atacama Desert in Chile was studied. Moraxella osloensis showed the greatest resistance and degradation capability of TBT, producing less toxic by-products, such as dibutyltin (DBT) and inorganic tin. In 7 days, approximately 80 % of TBT degradation was achieved, generating close to 20 % of DBT as degradation product. The degradation rate constant (k) was 0.022 [day(-1)] and TBT half-life (t1/2) in culture was 4.3 days. Debutylation is stated a probable mechanism of TBT degradation.

  14. Effects of tributyltin on placental cytokine production.

    Science.gov (United States)

    Arita, Yuko; Kirk, Michael; Gupta, Neha; Menon, Ramkumar; Getahun, Darios; Peltier, Morgan R

    2018-03-15

    Tributyltin (TBT) is a persistent pollutant but its effects on placental function are poorly understood as are its possible interactions with infection. We hypothesized that TBT alters the production of sex hormones and biomarkers for inflammation and neurodevelopment in an infection-dependent manner. Placental explant cultures were treated with 0-5000 nM TBT in the presence and absence of Escherichia coli. A conditioned medium was harvested and concentrations of steroids (progesterone, P4; testosterone, T and estradiol, E2) as well as biomarkers of inflammation [interleukin (IL)-1β (IL-1β), tumor necrosis factor (TNF-α), IL-10, IL-6, soluble glycoprotein 130 (sgp-130) and heme oxygenase-1 (HO-1)], oxidative stress [8-iso-prostaglandin (8-IsoP)] and neurodevelopment [brain-derived neurotrophic factor (BDNF)] were quantified. TBT increased P4 slightly but had little or no effect on T or E2 production. IL-1β, IL-6, sgp-130, IL-10 and 8-IsoP production was enhanced by TBT. P4 and IL-6 production was also enhanced by TBT for bacteria-stimulated cultures but TBT significantly inhibited bacteria-induced IL-1β and sgp-130 production. High doses of TBT also inhibited BDNF production. TBT increases P4 but has minimal effect on downstream steroids. It enhances the production of inflammatory biomarkers such as IL-1β, TNF-α, IL-10 and IL-6. Inhibition of sgp-130 by TBT suggests that TBT may increase bioactive IL-6 production which has been associated with adverse neurodevelopmental outcomes. Reduced expression of BDNF also supports this possibility.

  15. 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.

  16. 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.

  17. Iron status as a covariate in methylmercury-associated neurotoxicity risk

    DEFF Research Database (Denmark)

    Fonseca, Márlon de Freitas; De Souza Hacon, Sandra; Grandjean, Philippe

    2014-01-01

    Intrauterine methylmercury exposure and prenatal iron deficiency negatively affect offspring's brain development. Since fish is a major source of both methylmercury and iron, occurrence of negative confounding may affect the interpretation of studies concerning cognition. We assessed relationship...... between methylmercury exposure and iron-status in childbearing females from a population naturally exposed to methylmercury through fish intake (Amazon). We concluded a census (refuse...

  18. Occurrence of tributyltin compounds and characteristics of heavy metals

    International Nuclear Information System (INIS)

    Sheikh, M. A.; Oomori, T.; Noah, N. M.; Tsuha, K.

    2007-01-01

    Surface sediment samples were collected from Tanzanian major commercial ports and studied for the distribution and behavior of tributyltin compounds and heavy metals. The content of tributyltin in sediments ranged from ND-3670 ng (Sn) g 1 dry wt (1 780 ± 1720) (Mean ± SD) at Zanzibar and from ND-16700 ng (Sn)g 1 dry wt (4080 ± 7540) at Dar Es Salaam ports, respectively. Maximum tributyltin levels were detected inside the both ports. Metabolic degradation of butyltin compounds showed that MBT + DBT > TBT %, this may be attributed by the warm ambient water and intense sunlight in the tropical regions. A sequential extraction procedure was undertaken to provide detailed chemical characteristics of heavy metals in the sediments. The procedure revealed that about 50 % of Fe in the both ports is in immobile fraction (residual fraction) while other metals; Cd, Cu, Ni, Co, Zn, Pb. and Mn were mostly found in exchangeable or carbonate fractions and thus can be easily remobilized and enter the aquatic food chain. This paper provides basic information of tributyltin compounds contamination and chemical characteristics of heavy metals in the marine ecosystem in Tanzania. To our knowledge, this is the first documentation of Organotin compounds in marine environments in East Africa and suggests the importance of further detailed Organotin compounds studies in other sub-Saharan Africa regions

  19. Sublethal Effects of Tributyltin on the Hard Shell Clam, Mercenaria mercenaria,

    Science.gov (United States)

    1988-01-01

    7) Laughlin, R.8., Jr., R.G. Gustafson and Peter Distribution/ Pendoley. 1987. Acute toxicity of tributyltin Avaiabilty Cdes( TBT ) to early life...Dist rSpecial Gustafson. 1987. Chronic embryo larval toxicity I of tributyltin ( TBT ) to the hard shell clam, All Aercenaria mercenaria. In preparation... tributyltin compounds ( TBT ). Post-set clams microalgae, Isochyis galmna Tahiti strain. TBT survived exposures up to 7.5 1i / for 25 days. No corentrations in

  20. Sex difference in the principal cytochrome P-450 for tributyltin metabolism in rats

    International Nuclear Information System (INIS)

    Ohhira, Shuji; Enomoto, Mitsunori; Matsui, Hisao

    2006-01-01

    Tributyltin is metabolized by cytochrome P-450 (CYP) system enzymes, and its metabolic fate may contribute to the toxicity of the chemical. In the present study, it is examined whether sex differences in the metabolism of tributyltin exist in rats. In addition, the in vivo and in vitro metabolism of tributyltin was investigated using rat hepatic CYP systems to confirm the principal CYP involved. A significant sex difference in metabolism occurred both in vivo and in vitro, suggesting that one of the CYPs responsible for tributyltin metabolism in rats is male specific or predominant at least. Eight cDNA-expressed rat CYPs, including typical phenobarbital (PB)-inducible forms and members of the CYP2C subfamily, were tested to determine their capability for tributyltin metabolism. Among the enzymes studied, a statistically significant dealkylation of tributyltin was mediated by CYP2C6 and 2C11. Furthermore, the sex difference in metabolism disappeared in vitro after anti-rat CYP2C11 antibody pretreatment because CYP2C11 is a major male-specific form in rats. These results indicate that CYP2C6 is the principal CYP for tributyltin metabolism in female rats, whereas CYP2C11 as well as 2C6 is involved in tributyltin metabolism in male rats, and it is suggested that CYP2C11 is responsible for the significant sex difference in the metabolism of tributyltin observed in rats

  1. Accelerator Analysis of Tributyltin Adsorbed onto the Surface of a Tributyltin Resistant Marine Pseudoalteromonas sp. Cell

    Directory of Open Access Journals (Sweden)

    Akira Kitamura

    2008-10-01

    Full Text Available Tributyltin (TBT released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship’s ballast water. The isolate (109.3 ± 0.2 colony-forming units mL-1 adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 108.2. The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 106.8 TBT molecules is adsorbed by a single cell.

  2. Tributyltin impairs the reproductive cycle in female rats.

    Science.gov (United States)

    Lang Podratz, Priscila; Delgado Filho, Vicente Sathler; Lopes, Pedro Francisco Iguatemy; Cavati Sena, Gabriela; Matsumoto, Silvia Tamie; Samoto, Vivian Yochiko; Takiya, Christina Maeda; de Castro Miguel, Emilio; Silva, Ian Victor; Graceli, Jones Bernardes

    2012-01-01

    Triorganotins are environmental contaminants, commonly used in antifouling agents for boats, that bioaccumulate and thus are found in mammals and humans due to ingestion of contaminated seafood diets. The importance of triorganotins as environmental endocrine disruptors and consequent reproductive toxicity in different animal models is well known; however, the adverse effects on reproductive cycle are less well understood. The potential reproductive toxicity of tributyltin (TBT) on regular reproductive cycling of female rats was examined. Wistar female rats (12 wk old, weighing approximately 230 g) were divided into two groups: control (vehicle, ethanol 0.4%) and tributyltin (100 ng/kg/d, 7 d/wk, for 16 d by gavage). Tributyltin significantly decreased the cycle regularity (%), duration of the reproductive cycle, the proestrus and diestrus phases, and number of epithelial cell in proestrus phase. TBT also increased the duration of metestrus and the number of cornified cells in this phase. Ovary weight and serum 17β-estradiol levels decreased markedly, accompanied by a significant increase in progesterone levels. Histological analysis showed apoptotic cells in corpus luteum and granulosa cells layer, with cystic follicles after TBT exposure. Tributyltin also elevated number of atretic follicles and corpoa lutea. The micronucleus (MN) test, using Chinese hamster ovary cells, demonstrated a concentration-dependent mutagenic effect of TBT, and at 2.0 × 10(-2)ng/ml most of the cells were nonviable. The toxic potential of TBT over the reproductive cycle may be attributed to changes found in the ovarian weight, unbalanced levels of sexual female hormones, and number of ovarian follicles and corpora lutea.

  3. The remediation of tributyltin-contaminated dredgins and waters

    OpenAIRE

    Gkenakou, Evgenia-Varvara

    2008-01-01

    Tributyltin (TBT) is a pollutant, mainly introduced to the environment as a marine anti-fouling agent. The aim of this work was to assess and develop sustainable and cost-effective remediation technologies for TBT-contaminated dredged materials. For this purpose, analytical methods were developed for sediments and sediment leachates.For the sediments, a triple extraction followed by derivatisation and measurement by gas chromatography with pulsed flame photometric detection was employed, avoi...

  4. A Novel Role of MerC in Methylmercury Transport and Phytoremediation of Methylmercury Contamination.

    Science.gov (United States)

    Sone, Yuka; Uraguchi, Shimpei; Takanezawa, Yasukazu; Nakamura, Ryosuke; Pan-Hou, Hidemitsu; Kiyono, Masako

    2017-01-01

    MerC, encoded by merC in the transposon Tn21 mer operon, is a heavy metal transporter with potential applications for phytoremediation of heavy metals such as mercuric ion and cadmium. In this study, we demonstrate that MerC also acts as a transporter for methylmercury. When MerC was expressed in Escherichia coli XL1-Blue, cells became hypersensitive to CH 3 Hg(I) and the uptake of CH 3 Hg(I) by these cells was higher than that by cells of the isogenic strain. Moreover, transgenic Arabidopsis plants expressing bacterial MerC or MerC fused to plant soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) accumulated CH 3 Hg(I) effectively and their growth was comparable to the wild-type plants. These results demonstrate that when the bacterium-derived merC gene is ectopically introduced in genetically modified plants, MerC expression in the transgenic plants promotes the transport and sequestration of methylmercury. Thus, our results show that the expression of merC in Arabidopsis results in transgenic plants that could be used for the phytoremediation and elimination of toxic methylmercury from the environment.

  5. Transformation of tributyltin in zebrafish eleutheroembryos (Danio rerio).

    Science.gov (United States)

    Borges, Aline Rocha; López-Serrano Oliver, Ana; Gallego-Gallegos, Mercedes; Muñoz-Olivas, Riansares; Rodrigues Vale, Maria Goreti; Cámara, Carmen

    2014-12-01

    Organotin compounds are highly versatile group of organometallic chemicals used in industrial and agricultural applications. Their endocrine-disrupting effects are well known and their extensive uses as biocide materials, e.g., in antifouling paints, for many years have led to serious environmental problems. So far, attention has mainly been given to tributyltin pollution in water, sediments, and marine organisms because of its highly toxic effects and high accumulation levels at very low concentrations. In this study, we will focus on the conversion of tributyltin after it is absorbed by zebrafish eleutheroembryos, presented here as an alternative model to adult fish for describing bioconcentration. A simplified analytical extraction procedure based on the use of an assisted ultrasonic probe and derivatization by ethylation, followed by gas chromatography with a flame photometric detector (GC-FPD) is proposed. This classical methodology for organotin determination has been validated by inductively coupled plasma mass spectrometry (ICP-MS) and Zeeman graphite furnace atomic absorption spectrometry (ZGF-AAS) in terms of total tin content. The speciation analysis results show that zebrafish eleutheroembryos absorb high amounts of tributyltin and convert it into monobutyltin and likely in inorganic tin.

  6. Visual evoked potentials in children prenatally exposed to methylmercury

    DEFF Research Database (Denmark)

    Yorifuji, Takashi; Murata, Katsuyuki; Bjerve, Kristian S

    2013-01-01

    Prenatal exposure to methylmercury can cause both neurobehavioral deficits and neurophysiological changes. However, evidence of neurotoxic effects within the visual nervous system is inconsistent, possibly due to incomplete statistical adjustment for beneficial nutritional factors. We evaluated t...

  7. Effect of methylmercury on histamine release from rat mast cells

    Energy Technology Data Exchange (ETDEWEB)

    Graevskaya, Elizabeth E.; Rubin, Andrew B. [Moscow State University, Biological Faculty, Department of Biophysics, 119899, Vorobjovy Gory, Moscow (Russian Federation); Yasutake, Akira; Aramaki, Ryoji [National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008 (Japan)

    2003-01-01

    Methylmercury chloride (MeHgCl) is well known as a significant environmental hazard, particularly as a modulator of the immune system. As it is acknowledged that the critical effector cells in the host response participating in various biological responses are mast cells, we tried to define the possible contribution of mast cells in the development of methylmercury-evoked effects. We investigated the effects of methylmercury on the rat mast cell degranulation induced by non-immunological stimuli (the selective liberator of histamine, compound 48/80, and calcium ionophore A23187) both in vivo and in vitro. Using the cells prepared from methylmercury-intoxicated rats through a 5-day treatment of MeHgCl (10 mg/kg/day), we observed the suppression of calcium ionophore A23187- and 48/80-induced histamine release, which was enhanced with time after treatment. Similar suppression was observed in the ionophore-stimulated release, when cells were prepared from rat with a single treatment of MeHgCl (20 mg/kg). It should be noted that when cells from the control rat were pre-incubated with methylmercury in vitro at a 10{sup -8} M concentration for 10 min, A23187 and compound 48/80-stimulated histamine release was significantly enhanced. However, when the pre-incubation period was prolonged to 30 min, the release was suppressed. An increase in the methylmercury concentration to 10{sup -6} M also suppressed the histamine release. These results show that methylmercury treatment can modify mast cell function depending on concentration and time, and might provide an insight into the role of mast cells in the development of methylmercury-stimulated effects. (orig.)

  8. Phytoremediation of ionic and methylmercury pollution

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, Richard B. [Univ. of Georgia, Athens, GA (United States). Dept. of Genetics

    2010-04-28

    Our long-term goal is to enable highly productive plant species to extract, resist, detoxify, and sequester the toxic elemental pollutants, like the heavy metal mercury. Our current working hypothesis is that transgenic plants controlling the transport, chemical speciation, electrochemical state. volatilization, and aboveground binding of mercury will: a) tolerate mercury and grow rapidly in mercury contaminated environments; b) prevent methylmercury from entering the food chain; c) remove mercury from polluted soil and water; and d) hyperaccumulate mercury in aboveground tissues for later harvest. Progress toward these specific aims is reported: to increase the transport of mercury into roots and to aboveground vegetative organs; to increase biochemical sinks and storage for mercury in leaves; to increase leaf cell vacuolar storage of mercury; and to demonstrate that several stacked transgenes, when functioning in concert, enhance mercury resistance and hyperaccumulation to high levels.

  9. Mental retardation and prenatal methylmercury toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Trasande, L.; Schechter, C.B.; Haynes, K.A.; Landrigan, P.J. [CUNY Mt. Sinai School of Medicine, New York, NY (United States). Dept. of Community & Preventative Medicine

    2006-03-15

    Methylmercury (MeHg) is a developmental neurotoxicant; exposure results principally from consumption of seafood contaminated by mercury (Hg). In this analysis, the burden of mental retardation (MR) associated with methylmercury exposure in the 2000 U.S. birth cohort is estimated, and the portion of this burden attributable to mercury (Hg) emissions from coal-fired power plants is identified. The aggregate loss in cognition associated with MeHg exposure in the 2000 U.S. birth cohort was estimated using two previously published dose-response models that relate increases in cord blood Hg concentrations with decrements in IQ. MeHg exposure was assumed not to be correlated with native cognitive ability. Previously published estimates were used to estimate economic costs of MR caused by MeHg. Downward shifts in IQ resulting from prenatal exposure to MeHg of anthropogenic origin are associated with 1,566 excess cases of MR annually (range: 376-14,293). This represents 3.2% of MR cases in the US (range: 0.8%-29.2%). The MR costs associated with decreases in IQ in these children amount to $2.0 billion/year (range: $0.5-17.9 billion). Hg from American power plants accounts for 231 of the excess MR cases year (range: 28-2,109), or 0.5% (range: 0.06%-4.3%) of all MR. These cases cost $289 million (range: $35 million-2.6 billion). Toxic injury to the fetal brain caused by Hg emitted from coal-fired power plants exacts a significant human and economic toll on American children.

  10. Effects of in utero tributyltin chloride exposure in the rat on pregnancy outcome.

    Science.gov (United States)

    Adeeko, Adedayo; Li, Daming; Forsyth, Don S; Casey, Valerie; Cooke, Gerard M; Barthelemy, Johanna; Cyr, Daniel G; Trasler, Jacquetta M; Robaire, Bernard; Hales, Barbara F

    2003-08-01

    Tributyltin, an organotin, is ubiquitous in the environment. The consumption of contaminated marine species leads to human dietary exposure to this compound. Tributyltin is an endocrine disruptor in many wildlife species and inhibits aromatase in mammalian placental and granulosa-like tumor cell lines. We investigated the effects of tributyltin chloride exposure on pregnancy outcome in the Sprague-Dawley rat. Timed pregnant rats were gavaged either with vehicle (olive oil) or tributyltin chloride (0.25, 2.5, 10, or 20 mg/kg) from days 0-19 or 8-19 of gestation. On gestational day 20, dams were sacrificed, and pregnancy outcome was determined. Tributyltin and its metabolites (dibutyltin, monobutyltin) were measured in maternal blood by gas chromatography. Both tributyltin and dibutyltin were present in maternal blood at approximately equal concentrations, whereas monobutyltin contributed minimally to total organotins. Organotin concentrations increased in a dose-dependent pattern in dams, independent of the window of exposure. Tributyltin chloride administration significantly reduced maternal weight gain only at the highest dose (20 mg/kg); a significant increase in post-implantation loss and decreased litter sizes, in addition to decreased fetal weights, was observed in this group. Tributyltin chloride exposure did not result in external malformations, nor was there a change in sex ratios. However, exposure to 0.25, 2.5, or 10 mg/kg tributyltin chloride from gestation days (GD) 0-19 resulted in a significant increase in normalized anogenital distances in male fetuses; exposure from days 8-19 had no effect. There was a dramatic increase in the incidence of low weight (exposure to 20 mg/kg tributyltin chloride. Delayed ossification of the fetal skeleton was observed after in utero exposure to either 10 mg/kg or 20 mg/kg tributyltin chloride. Serum thyroxine and triiodothyronine levels were reduced significantly in dams exposed to 10 and 20 mg/kg tributyltin chloride

  11. Tributyltin-resistant bacteria from estuarine and freshwater sediments.

    OpenAIRE

    Wuertz, S; Miller, C E; Pfister, R M; Cooney, J J

    1991-01-01

    Resistance to tributyltin (TBT) was examined in populations from TBT-polluted sediments and nonpolluted sediments from an estuary and from fresh water as well as in pure cultures isolated from those sediments. The 50% effective concentrations (EC50s) for populations were higher at a TBT-polluted freshwater site than at a site without TBT, suggesting that TBT selected for a TBT-resistant population. In contrast, EC50s were significantly lower for populations from a TBT-contaminated estuarine s...

  12. Regioselectivity of tributyltin ether mediated alkylations. A 119Sn and 13C NMR study

    International Nuclear Information System (INIS)

    Cruzado, C.; Bernabe, M.; Martin-Lomas, M.

    1989-01-01

    The 119 Sn and 13 C NMR spectra of the stannylated species resulting from the treatment of conformationally rigid polyhydroxylated compounds with bis(tributyltin) oxide have been determined and the effect of N-methylimidazole, added as catalyst in tributyltin ether mediated regioselective alkylations, has been investigated. The observed signal intensity changes, upfield shifts, signal broadenings, and the results of variable temperature experiments have been interpreted as indicative of the selective formation of pentacoordinated tin species, involving conveniently disposed adjacent hydroxyl groups, on addition of the catalyst. On these bases, a mechanistic hypothesis for the observed regioselectivity of N-methylimidazole-catalyzed tributyltin ether mediated benzylations is proposed. 13 references, 5 tables

  13. Effects of Tributyltin Antifouling Paint Leachates on Pearl Harbor Organisms. Site-Specific Flowthrough Bioassay Tests.

    Science.gov (United States)

    1985-12-01

    painted with a commercial ablative co-polymer coating containing tributyltin and cuprous oxide toxicants were "aged" for 4 months in flowing seawater...a 2-month recovery phase after removing the panels. Mean measured tributyltin ( TBT ) concentrations in leachate treatments were 0.04, 0.1. 0.5. 1 8...facility of Naval Ocean Systems Center (NOSC) at Mokapu. Oahu. Hawaii. In those experiments, exposure to 0.5 to 1.8 #g/L tributyltin ( TBT ) resulted in

  14. Methylmercury, fish consumption, and the precautionary principle

    Energy Technology Data Exchange (ETDEWEB)

    Fred Lipfert; Sam Morris; Terry Sullivan; Paul Moskowitz; Scott Renninger

    2005-04-01

    This paper considers several broad issues in the context of probabilistic assessment of the benefits of curtailing mercury (Hg) emissions from coal-fired power plants in the USA, based on information developed from recent literature and epidemiology studies of health effects of methylmercury. Exposure of the U.S. population is considered on the national scale, in large part because of recent questions arising from survey and experimental data about the relative importance of local deposition of airborne Hg. Although epidemiological studies have provided useful information, safe levels of Hg exposure remain uncertain, in part because of other dietary considerations in the populations that were studied. For example, much of the seafood consumed in one of the major studies was also contaminated with polychlorinated biphenyls, as are fish taken from some U.S. fresh waters. The primary epidemiological approach involves cross-study comparisons in relation to mean exposures, rather than detailed critiques of individual effects reported in each study. U.S. exposures are seen to be well below the levels at which adverse health effects are reported. This analysis supports the conclusion that unilateral reduction of Hg emissions from U.S. coal-fired power plants alone is unlikely to realize significant public health benefits. 79 refs., 2 figs., 2 tabs.

  15. Biochemical Factors Modulating Cellular Neurotoxicity of Methylmercury

    Directory of Open Access Journals (Sweden)

    Parvinder Kaur

    2011-01-01

    Full Text Available Methylmercury (MeHg, an environmental toxicant primarily found in fish and seafood, poses a dilemma to both consumers and regulatory authorities, given the nutritional benefits of fish consumption versus the possible adverse neurological damage. Several studies have shown that MeHg toxicity is influenced by a number of biochemical factors, such as glutathione (GSH, fatty acids, vitamins, and essential elements, but the cellular mechanisms underlying these complex interactions have not yet been fully elucidated. The objective of this paper is to outline the cellular response to dietary nutrients, as well as to describe the neurotoxic exposures to MeHg. In order to determine the cellular mechanism(s of toxicity, the effect of pretreatment with biochemical factors (e.g., N-acetyl cysteine, (NAC; diethyl maleate, (DEM; docosahexaenoic acid, (DHA; selenomethionine, SeM; Trolox and MeHg treatment on intercellular antioxidant status, MeHg content, and other endpoints was evaluated. This paper emphasizes that the protection against oxidative stress offered by these biochemical factors is among one of the major mechanisms responsible for conferring neuroprotection. It is therefore critical to ascertain the cellular mechanisms associated with various dietary nutrients as well as to determine the potential effects of neurotoxic exposures for accurately assessing the risks and benefits associated with fish consumption.

  16. Mercury and methylmercury in reservoirs in Indiana

    Science.gov (United States)

    Risch, Martin R.; Fredericksen, Amanda L.

    2015-01-01

    Mercury (Hg) is an element that occurs naturally, but evidence suggests that human activities have resulted in increased amounts being released to the atmosphere and land surface. When Hg is converted to methylmercury (MeHg) in aquatic ecosystems, MeHg accumulates and increases in the food web so that some fish contain levels which pose a health risk to humans and wildlife that consume these fish. Reservoirs unlike natural lakes, are a part of river systems that are managed for flood control. Data compiled and interpreted for six flood-control reservoirs in Indiana showed a relation between Hg transport, MeHg formation in water, and MeHg in fish that was influenced by physical, chemical, and biological differences among the reservoirs. Existing information precludes a uniform comparison of Hg and MeHg in all reservoirs in the State, but factors and conditions were identified that can indicate where and when Hg and MeHg levels in reservoirs could be highest.

  17. Negative confounding by essential fatty acids in methylmercury neurotoxicity associations

    DEFF Research Database (Denmark)

    Choi, Anna L; Mogensen, Ulla Brasch; Bjerve, Kristian S

    2014-01-01

    acid concentrations in the analysis (-22.0, 95% confidence interval [CI]=-39.4, -4.62). In structural equation models, poorer memory function (corresponding to a lower score in the learning trials and short delay recall in CVLT) was associated with a doubling of prenatal exposure to methylmercury after...... concentrations of fatty acids were determined in cord serum phospholipids. Neuropsychological performance in verbal, motor, attention, spatial, and memory functions was assessed at 7 years of age. Multiple regression and structural equation models (SEMs) were carried out to determine the confounder......-adjusted associations with methylmercury exposure. RESULTS: A short delay recall (in percent change) in the California Verbal Learning Test (CVLT) was associated with a doubling of cord blood methylmercury (-18.9, 95% confidence interval [CI]=-36.3, -1.51). The association became stronger after the inclusion of fatty...

  18. Determination of methylmercury salts in various kinds of biological material

    Energy Technology Data Exchange (ETDEWEB)

    Westoeoe, G

    1968-01-01

    The cysteine acetate modification of the method for determining methylmercury salts in foods, which was useful for analysis of fish, egg white, and meat, was not efficient when applied to egg yolk with low methylmercury content, liver, sediments in aquaria, or sludge. Therefore some modifications of the procedure have been investigated. A combination of the mercuric chloride and cysteine acetate procedures gave good results for sediments in aquaria and sludge and could also be used for, e.g., fish, egg white, bile, kidney, blood, meat, and moss. Precipitation of the proteins with molybdic acid at the first extraction improved the results for liver but not for egg yolk. For egg yolk an increase of the concentration of the cysteine acetate solution from 1 to 10% gave 90% recovery of added methylmercury, repeated extractions 100% recovery. 5 references, 2 tables.

  19. Tributyltin accumulation and effects in marine molluscs from West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Strand, J.; Asmund, G

    2003-05-01

    Tributyltin is accumulated in marine molluscs living in Greenland, with the highest levels found in harbour areas. - The levels of the antifouling agent tributyltin (TBT) and its breakdown products in bivalves were investigated in 1999-2000 at six areas along the west coast of Greenland with focus on locations inside and outside harbours. In addition female gastropods were examined for the development of TBT-induced masculine characteristics in form of imposex or intersex. The highest TBT concentration, 254 ng g{sup -1} ww, was found in the bivalve Mytilus edulis sampled inside Nuuk harbour, but significant TBT concentrations were also present in bivalves from the other harbour areas. Only low levels of TBT were detected in bivalves sampled outside the harbours and in several of the samples the TBT level was below the detection limit. The examination of neogastropods like Buccinum revealed that imposex development occurred in all the harbours. In contrast, imposex was not found in any neogastropods sampled outside the harbour areas. However, the value of marine neogastropods as indicators of TBT contamination in West Greenland seems limited, because of large species diversity and the difficulties in sampling enough specimens at least with the current sampling strategy. No effects, which could be related to TBT contamination, were found in the most abundant tidal gastropod in West Greenland, Littorina saxatilis.

  20. Tributyltin accumulation and effects in marine molluscs from West Greenland

    International Nuclear Information System (INIS)

    Strand, J.; Asmund, G.

    2003-01-01

    Tributyltin is accumulated in marine molluscs living in Greenland, with the highest levels found in harbour areas. - The levels of the antifouling agent tributyltin (TBT) and its breakdown products in bivalves were investigated in 1999-2000 at six areas along the west coast of Greenland with focus on locations inside and outside harbours. In addition female gastropods were examined for the development of TBT-induced masculine characteristics in form of imposex or intersex. The highest TBT concentration, 254 ng g -1 ww, was found in the bivalve Mytilus edulis sampled inside Nuuk harbour, but significant TBT concentrations were also present in bivalves from the other harbour areas. Only low levels of TBT were detected in bivalves sampled outside the harbours and in several of the samples the TBT level was below the detection limit. The examination of neogastropods like Buccinum revealed that imposex development occurred in all the harbours. In contrast, imposex was not found in any neogastropods sampled outside the harbour areas. However, the value of marine neogastropods as indicators of TBT contamination in West Greenland seems limited, because of large species diversity and the difficulties in sampling enough specimens at least with the current sampling strategy. No effects, which could be related to TBT contamination, were found in the most abundant tidal gastropod in West Greenland, Littorina saxatilis

  1. Fact Sheet: Notice of Ambient Water Quality Criteria Document for Tributyltin (TBT) - Final

    Science.gov (United States)

    Information pertaining to 2004 Final Acute and Chronic Ambient Aquatic Life Water Quality Criteria for Tributyltin (TBT) for freshwater and saltwater. This fact sheet includes the safe levels of TBT that should protect the majority of species.

  2. Neurotoxic response of infant monkeys to methylmercury

    Energy Technology Data Exchange (ETDEWEB)

    Willes, R.F.; Truelove, J.F.; Nera, E.A.

    1978-02-01

    Four infant monkeys were dosed orally with 500 ..mu..g Hg/kg body wt./day (as methylmercury (MeHg) chloride dissolved sodium carbonate) beginning at 1 day of age. Neurological and behavioral signs of MeHg toxicity and blood Hg levels were monitored weekly. At first sign of MeHg intoxication, dosing with MeHg was terminated and the infants were monitored to assess reversal of the signs of MeHg toxicity. The first signs of MeHg toxicity, exhibited as a loss in dexterity and locomotor ability, were observed after 28 to 29 days of treatment; the blood Hg levels were 8.0 to 9.4 ..mu..g Hg/g blood. Dosing was terminated at 28 to 29 days of treatment but the signs of MeHg toxicity continued to develop. The infants became ataxic, blind, comatose and were necropsied at 35 to 43 days after initiating treatment with MgHg. The mercury concentrations in tissues analyzed after necropsy were highest in liver followed by occipital cortex and renal cortex. The mean blood/brain ratio was 0.21 +- 0.4. Histopathologic lesions were marked in the cerebrum with less severe lesions in the cerebellar nuclei. The Purkinje and granular cells of the cerebellar vermis appeared histologically normal. Lesions were not observed in the peripheral nervous system. The signs of MeHg intoxication, the tissue distribution of MeHg and histopathologic lesions observed in the infant monkeys were similar to those reported for adult monkeys.

  3. Neurotoxic response of infant monkeys to methylmercury.

    Science.gov (United States)

    Willes, R F; Truelove, J F; Nera, E A

    1978-02-01

    Four infant monkeys were dosed orally with 500 microgram Hg/kg body wt./day /as methylmercury (MeHg) chloride dissolved sodium carbonate) beginning at 1 day of age. Neurological and behavioral signs of MeHg toxicity and blood Hg levels were monitored weekly. At first sign of MeHg intoxication, dosing with MeHg was terminated and the infants were monitored to assess reversal of the signs of MeHg toxicity. The first signs of MeHg toxicity, exhibited as a loss in dexterity and locomotor ability, were observed after 28--29 days of treatment; the blood Hg levels were 8.0--9.4 microgram Hg/g blood. Dosing was terminated at 28--29 days of treatment but the signs of MeHg toxicity continued to develop. The infants became ataxic, blind, comatose and were necropsied at 35--43 days after initiating treatment with MgHg. The mercury concentrations in tissues analyzed after necropsy were highest in liver (55.8 +/- 3.2 microgram Hg/g) followed by occipital cortex (35.6 +/- 4.8 microgram Hg/g) renal cortex (32.8 +/- 1.6 microgram Hg/g). The frontal and temporal cortices had 27.0 +/- 3.4 and 29.6 +/- 4.9 microgram Hg/g respectively while the cerebellar Hg concentration averaged 13.0 +/- 1.5 microgram Hg/g. The mean blood/brain ratio was 0.21 +/- 0.4. Histopathologic lesions were marked in the cerebrum with less severe lesions in the cerebellar nuclei. The Purkinje and granular cells of the cerebellar vermis appeared histologically normal. Lesions were not observed in the peripheral nervous system. The signs of MeHg intoxication, the tissue distribution of MeHg and histopathologic lesions observed in the infant monkeys were similar to those reported for adult monkeys.

  4. Sublethal Growth Effects and Mortality to Marine Bivalves and Fish from Long-Term Exposure to Tributyltin.

    Science.gov (United States)

    1985-07-01

    sublethal toxicity of tributyltin oxide (TBTO) and its putative environmental product, tribu- tyltin sulfide ( TBTS ) to zoeal mud crabs, RIthropanopeus...Organotin .,’vwfuf coatingsu~~ study better defines the longterm toxicity and bloaccumnulation potential of tributyltin released from antifouting...larval fish survival at low tributyltin concentrations were also tested. Acute toxicity tests (96 hours) were con- ducted with mysid shrmp (Aawhomyot

  5. Methylmercury bioaccumulation in invertebrates of boreal streams in Norway: Effects of aqueous methylmercury and diet retention

    International Nuclear Information System (INIS)

    Wit, Heleen A. de; Kainz, Martin J.; Lindholm, Markus

    2012-01-01

    Transfer of aqueous methylmercury (MeHg) to primary consumers in aquatic foodwebs is poorly understood despite its importance for bioaccumulation of MeHg. We studied bioaccumulation of MeHg in simple aquatic food chains of two humic boreal streams in relation to streamwater chemistry, food web characteristics and dietary fatty acid (FA) biomarkers. Transfer of aqueous MeHg into primary consumers was similar in both streams, resulting in higher MeHg in consumers in the MeHg-rich stream. Trophic enrichment of MeHg and dietary retention of FA biomarkers was the same in both streams, suggesting that exposure to aqueous MeHg at the base of the food chain determined levels of MeHg in biota. In addition, contents of dietary biomarkers suggested that ingestion of algae reduced MeHg bioaccumulation, while ingestion of bacteria stimulated MeHg uptake. Dietary uptake of bacteria could thus be an important pathway for MeHg-transfer at the bottom of food chains in humic streams. - Highlights: ► We examined MeHg bioaccumulation in simple food chains in two boreal streams. ► Higher MeHg in invertebrates was associated with higher aqueous MeHg. ► Dietary biomarkers showed that consumers in both streams accessed similar food sources. ► We concluded at exposure to aqueous MeHg determined bioaccumulation of MeHg. ► Seasonal variation in MeHg in biota could be related to diet using dietary biomarkers. - Exposure to aqueous methylmercury at the base of the food chain in boreal streams determines mercury in aquatic biota at higher trophic levels.

  6. Effects of tributyltin on early life-stage, reproduction, and gonadal sex differentiation in Japanese medaka (Oryzias latipes).

    Science.gov (United States)

    Horie, Yoshifumi; Yamagishi, Takahiro; Shintaku, Yoko; Iguchi, Taisen; Tatarazako, Norihisa

    2018-07-01

    Tributyltin, an organotin compound, was used worldwide as an antifouling agent in aquatic environments and there has been much concern about the toxicological and ecotoxicological properties of organotin compounds. Even though it has been prohibited worldwide, tributyltin is still detected at low concentrations in aquatic environments. Here we investigated the effects of tributyltin on the early life-stage, reproduction, and gonadal sex differentiation in Japanese medaka (Oryzias latipes). In adults, exposure to tributyltin at 3.82 μg/L suppressed fecundity and fertility and increased mortality. At 10.48 μg/L all medaka died by the sixth day of exposure. Exposure to tributyltin during early life-stages induced no significant differences in mortality or embryonic development, but growth was suppressed in groups exposed to 0.13 and 0.68 μg/L. Furthermore, there was no abnormal gonadal development in Japanese medaka exposed to tributyltin. These results provide evidence of the negative effects of tributyltin on reproduction in a teleost fish. Tributyltin did not affect gonadal sex differentiation in Japanese medaka, but fecundity and fertility were suppressed, although it is not clear whether this suppression resulted from the endocrine-disrupting action of tributyltin or its toxicity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Teratogenic interactions between methylmercury and mitomycin-C in mice

    Energy Technology Data Exchange (ETDEWEB)

    Inouye, Minoru; Kajiwara, Yuji

    1988-01-01

    Pregnant mice were given p.o. various nonteratogenic doses (0, 2.5 and 10 mg/kg) of methylmercuric chloride on day 9 of pregnancy, and then injected i.p. with a teratogenic dose (4 mg/kg) of mitomycin-C on day 10. Major malformations produced by mitomycin-C alone were cervical rib and vertebral anomaly, polydactyly of the hindlimb and tail anomaly. Combined treatment significantly increased the incidence of these malformations, showing the dose-effect relationship of methylmercury, whereas methylmercury alone is known not to produce such malformations. When mitomycin-C treatment alone was performed on day 9.5 of pregnancy, only vertebral anomalies increased in incidence. Therefore, mitomycin-C teratogenicity in terms of the manifestation of cervical rib, polydactyly and tail anomaly, but not vertebral anomaly, was suggested to be enhanced by methylmercury. A considerable number of foetuses showed cleft palate involvement following combined treatments, but not by either chemical alone. Cleft palate is known to be a major malformation in mice that is caused by methylmercury, and mitomycin-C also induces cleft palate. Therefore, the two chemicals might have affected foetuses additively and thereby induced cleft palate. (orig.)

  8. Disease burden of methylmercury in the German birth cohort 2014.

    Directory of Open Access Journals (Sweden)

    Julia Lackner

    Full Text Available This study aimed to estimate the disease burden of methylmercury for children born in Germany in the year 2014. Humans are mainly exposed to methylmercury when they eat fish or seafood. Prenatal methylmercury exposure is associated with IQ loss. To quantify this disease burden, we used Monte Carlo simulation to estimate the incidence of mild and severe mental retardation in children born to mothers who consume fish based on empirical data. Subsequently, we calculated the disease burden with the disability-adjusted life years (DALY-method. DALYs combine mortality and morbidity in one measure and quantify the gap between an ideal situation, where the entire population experiences the standard life expectancy without disease and disability, and the actual situation. Thus, one DALY corresponds to the loss of one year of life in good health. The methylmercury-induced burden of disease for the German birth cohort 2014 was an average of 14,186 DALY (95% CI 12,915-15,440 DALY. A large majority of the DALYs was attributed to morbidity as compared to mortality. Of the total disease burden, 98% were attributed to mild mental retardation, which only leads to morbidity. The remaining disease burden was a result of severe mental retardation with equal proportions of premature death and morbidity.

  9. Methylmercury exposure and adverse cardiovascular effects in Faroese whaling men

    DEFF Research Database (Denmark)

    Choi, Anna L; Weihe, Pal; Budtz-Jørgensen, Esben

    2009-01-01

    BACKGROUND: Methylmercury (MeHg), a worldwide contaminant found in fish and seafood, has been linked to an increased risk of cardiovascular mortality. OBJECTIVE: We examined 42 Faroese whaling men (30-70 years of age) to assess possible adverse effects within a wide range of MeHg exposures from...

  10. Adverse effects of methylmercury: environmental health research implications

    DEFF Research Database (Denmark)

    Grandjean, Philippe; Satoh, Hiroshi; Murata, Katsuyuki

    2010-01-01

    the recognition of methylmercury as a cause of serious human poisonings in Minamata, Japan. Developmental neurotoxicity was first reported in 1952, but despite accumulating evidence, the vulnerability of the developing nervous system was not taken into account in risk assessment internationally until...

  11. METHYLMERCURY EFFECTS ON NEUROTROPHIN SIGNALING IN PC12 CELLS.

    Science.gov (United States)

    Exposure to methylmercury (CH 3 Hg) can cause disruption in the development of the nervous system but the underlying mechanism of action is unclear. Previous in vivo studies in our laboratory have shown that developmental exposure to CH 3 Hg resulted in changes in neurotrophic fa...

  12. Photolytic degradation of methylmercury enhanced by binding to natural organic ligands

    Science.gov (United States)

    Zhang, Tong; Hsu-Kim, Heileen

    2010-07-01

    Methylmercury is a neurotoxin that accumulates in food webs and poses a significant risk to human health. In natural water bodies, methylmercury concentrations remain low due to the degradation of methylmercury into inorganic mercury by sunlight, a process known as photodecomposition. Rates of photodecomposition are relatively rapid in freshwater lakes, and slow in marine waters, but the cause of this difference is not clear. Here, we carry out incubation experiments with artificial freshwater and seawater samples to examine the mechanisms regulating methylmercury photodecomposition. We show that singlet oxygen-a highly reactive form of dissolved oxygen generated by sunlight falling on dissolved organic matter-drives photodecomposition. However, in our experiments the rate of methylmercury degradation depends on the type of methylmercury-binding ligand present in the water. Relatively fast degradation rates (similar to observations in freshwater lakes) were detected when methylmercury species were bound to sulphur-containing ligands such as glutathione and mercaptoacetate. In contrast, methylmercury-chloride complexes, which are the dominant form of methylmercury in marine systems, did not degrade as easily. Our results could help to explain why methylmercury photodecomposition rates are relatively rapid in freshwater lakes and slow in marine waters.

  13. Biotransformation of Tributyltin chloride by Pseudomonas stutzeri strain DN2

    Directory of Open Access Journals (Sweden)

    Dnyanada S. Khanolkar

    2014-12-01

    Full Text Available A bacterial isolate capable of utilizing tributyltin chloride (TBTCl as sole carbon source was isolated from estuarine sediments of west coast of India and identified as Pseudomonas stutzeri based on biochemical tests and Fatty acid methyl ester (FAME analysis. This isolate was designated as strain DN2. Although this bacterial isolate could resist up to 3 mM TBTCl level, it showed maximum growth at 2 mM TBTCl in mineral salt medium (MSM. Pseudomonas stutzeri DN2 exposed to 2 mM TBTCl revealed significant alteration in cell morphology as elongation and shrinkage in cell size along with roughness of cell surface. FTIR and NMR analysis of TBTCl degradation product extracted using chloroform and purified using column chromatography clearly revealed biotransformation of TBTCl into Dibutyltin dichloride (DBTCl2 through debutylation process. Therefore, Pseudomonas stutzeri strain DN2 may be used as a potential bacterial strain for bioremediation of TBTCl contaminated aquatic environmental sites.

  14. Biotransformation of Tributyltin chloride by Pseudomonas stutzeri strain DN2

    Science.gov (United States)

    Khanolkar, Dnyanada S.; Naik, Milind Mohan; Dubey, Santosh Kumar

    2014-01-01

    A bacterial isolate capable of utilizing tributyltin chloride (TBTCl) as sole carbon source was isolated from estuarine sediments of west coast of India and identified as Pseudomonas stutzeri based on biochemical tests and Fatty acid methyl ester (FAME) analysis. This isolate was designated as strain DN2. Although this bacterial isolate could resist up to 3 mM TBTCl level, it showed maximum growth at 2 mM TBTCl in mineral salt medium (MSM). Pseudomonas stutzeri DN2 exposed to 2 mM TBTCl revealed significant alteration in cell morphology as elongation and shrinkage in cell size along with roughness of cell surface. FTIR and NMR analysis of TBTCl degradation product extracted using chloroform and purified using column chromatography clearly revealed biotransformation of TBTCl into Dibutyltin dichloride (DBTCl2) through debutylation process. Therefore, Pseudomonas stutzeri strain DN2 may be used as a potential bacterial strain for bioremediation of TBTCl contaminated aquatic environmental sites. PMID:25763027

  15. Tributyltin exposure causes brain damage in Sebastiscus marmoratus.

    Science.gov (United States)

    Zhang, Jiliang; Zuo, Zhenghong; Chen, Rong; Chen, Yixin; Wang, Chonggang

    2008-09-01

    Tributyltin (TBT) is a ubiquitous marine environmental contaminant characterized primarily by its reproductive toxicity. However, the neurotoxic effect of TBT has not been extensively described, especially in fishes which have a high number of species in the marine environment. This study was conducted to investigate the neurotoxic effects of TBT at environmental levels (1, 10, and 100ngl(-1)) on female Sebastiscus marmoratus. The results showed that TBT exposure induced apoptosis in brain cells of three regions including the pallial areas of the telencephalon, the granular layer of the optic tectum, and the cerebellum. In addition, the increase of reactive oxygen species and nitric oxide levels, and the decrease of Na+/K+-ATPase activity were found in the brain. The results strongly indicated neurotoxicity of TBT to fishes. According to the regions in which apoptosis was found in the brain, TBT exposure might influence the schooling, sensory and motorial functions of fishes.

  16. Species differences in the sensitivity of avian embryos to methylmercury

    Science.gov (United States)

    Heinz, G.H.; Hoffman, D.J.; Klimstra, J.D.; Stebbins, K.R.; Kondrad, S.L.; Erwin, C.A.

    2009-01-01

    We injected doses of methylmercury into the air cells of eggs of 26 species of birds and examined the dose-response curves of embryo survival. For 23 species we had adequate data to calculate the median lethal concentration (LC50). Based on the dose-response curves and LC50s, we ranked species according to their sensitivity to injected methylmercury. Although the previously published embryotoxic threshold of mercury in game farm mallards (Anas platyrhynchos) has been used as a default value to protect wild species of birds, we found that, relative to other species, mallard embryos are not very sensitive to injected methylmercury; their LC50 was 1.79 ug/g mercury on a wet-weight basis. Other species we categorized as also exhibiting relatively low sensitivity to injected methylmercury (their LC50s were 1 ug/g mercury or higher) were the hooded merganser (Lophodytes cucullatus), lesser scaup (Aythya affinis), Canada goose (Branta canadensis), double-crested cormorant (Phalacrocorax auritus), and laughing gull (Larus atricilla). Species we categorized as having medium sensitivity (their LC50s were greater than 0.25 ug/g mercury but less than 1 ug/g mercury) were the clapper rail (Rallus longirostris), sandhill crane (Grus canadensis), ring-necked pheasant (Phasianus colchicus), chicken (Gallus gallus), common grackle (Quiscalus quiscula), tree swallow (Tachycineta bicolor), herring gull (Larus argentatus), common tern (S terna hirundo), royal tern (Sterna maxima), Caspian tern (Sterna caspia), great egret (Ardea alba), brown pelican (Pelecanus occidentalis), and anhinga (Anhinga anhinga). Species we categorized as exhibiting high sensitivity (their LC50s were less than 0.25 ug/g mercury) were the American kestrel (Falco sparverius), osprey (Pandion haliaetus), white ibis (Eudocimus albus), snowy egret (Egretta thula), and tri-colored heron (Egretta tricolor). For mallards, chickens, and ring-necked pheasants (all species for which we could compare the toxicity of our

  17. Metabolism of tributyltin and triphenyltin by rat, hamster and human hepatic microsomes

    Energy Technology Data Exchange (ETDEWEB)

    Ohhira, Shuji; Watanabe, Masatomo; Matsui, Hisao [Department of Hygiene, Dokkyo University School of Medicine, Mibu-machi, 321-0293, Tochigi (Japan)

    2003-03-01

    Tributyltin and triphenyltin are metabolized by cytochrome P-450 system enzymes, and their metabolic fate may contribute to the toxicity of the chemicals. In the current study, the in vitro metabolism of tributyltin and triphenyltin by rat, hamster and human hepatic microsomes was investigated to elucidate the metabolic competence for these compounds in humans. The metabolic reaction using microsome-NADPH system that is usually conducted was not applicable to in vitro metabolism of organotins, especially triphenyltin. We therefore examined the effects of dithiothreitol (DTT), one of the antioxidants for sulfhydryl groups, to determine the in vitro metabolism of tributyltin and triphenyltin. As a result, the treatment with 0.1 mM DTT in vitro increased the activity of the microsomal monooxygenase system for metabolism of tributyltin as well as triphenyltin; the total yield of tributyltin and triphenyltin metabolites as tin increased, respectively, by approximately 1.8 and 8.9 times for rat, 2.1 and 1.2 times for hamster, and 1.6 and 1.5 times for human. It is suggested that the organotins directly inactivate cytochrome P-450 because of the interaction with critical sulfhydryl groups of the hemoprotein. We confirmed the utility of this in vitro metabolic system using DTT in the hepatic microsomes of phenobarbital (PB)-pretreated and untreated hamsters. Thus, the in vitro metabolic system described here was applied to a comparative study of the metabolism of organotins in rats, hamsters and humans. Tributyltin was metabolized more readily than triphenyltin in all the species. In humans, the in vitro metabolic pattern resembled that of hamsters, which were susceptible to in vivo triphenyltin toxicity because of incompetent metabolism. It is possible that the hamster is a qualitatively and quantitatively suitable animal model for exploring the influence of tributyltin and triphenyltin in humans. (orig.)

  18. FISH CONSUMPTION, METHYLMERCURY, AND HUMAN HEART DISEASE.

    Energy Technology Data Exchange (ETDEWEB)

    LIPFERT, F.W.; SULLIVAN, T.M.

    2005-09-21

    Environmental mercury continues to be of concern to public health advocates, both in the U.S. and abroad, and new research continues to be published. A recent analysis of potential health benefits of reduced mercury emissions has opened a new area of public health concern: adverse effects on the cardiovascular system, which could account for the bulk of the potential economic benefits. The authors were careful to include caveats about the uncertainties of such impacts, but they cited only a fraction of the applicable health effects literature. That literature includes studies of the potentially harmful ingredient (methylmercury, MeHg) in fish, as well as of a beneficial ingredient, omega-3 fatty acids or ''fish oils''. The U.S. Food and Drug Administration (FDA) recently certified that some of these fat compounds that are primarily found in fish ''may be beneficial in reducing coronary heart disease''. This paper briefly summarizes and categorizes the extensive literature on both adverse and beneficial links between fish consumption and cardiovascular health, which are typically based on studies of selected groups of individuals (cohorts). Such studies tend to comprise the ''gold standard'' of epidemiology, but cohorts tend to exhibit a great deal of variability, in part because of the limited numbers of individuals involved and in part because of interactions with other dietary and lifestyle considerations. Note that eating fish will involve exposure to both the beneficial effects of fatty acids and the potentially harmful effects of contaminants like Hg or PCBs, all of which depend on the type of fish but tend to be correlated within a population. As a group, the cohort studies show that eating fish tends to reduce mortality, especially due to heart disease, for consumption rates up to about twice weekly, above which the benefits tend to level off. A Finnish cohort study showed increased mortality risks

  19. Testosterone-Fatty Acid esterification: a unique target for the endocrine toxicity of tributyltin to gastropods.

    Science.gov (United States)

    Leblanc, Gerald A; Gooding, Meredith P; Sternberg, Robin M

    2005-01-01

    Over the past thirty years, a global occurrence of sexual aberration has occurred whereby females among populations of prosobranch snails exhibit male sex characteristics. This condition, called imposex, has been causally associated with exposure to the biocide tributyltin. Tributyltin-exposed, imposex snails typically have elevated levels of testosterone which have led to the postulate that this endocrine dysfunction is responsible for imposex. This overview describes recent evidence that supports this postulate. Gastropods maintain circulating testosterone levels and administration of testosterone to females or castrates stimulates male sex differentiation in several snail species. Studies in the mud snail (Ilyanassa obsoleta) have shown that gastropods utilize a unique strategy for regulating free testosterone levels. Excess testosterone is converted to fatty acid esters by the action of a testosterone-inducible, high capacity/low affinity enzyme, acyl-CoA:testosterone acyl transferase, and stored within the organisms. Free testosterone levels are regulated during the reproductive cycle apparently due to changes in esterification/desterification suggesting that testosterone functions in the reproductive cycle of the organisms. Testosterone esterification provides a unique target in the testosterone regulatory machinery of snails that is altered by tributyltin. Indeed, imposex and free testosterone levels were elevated in field collected snails containing high tin levels, while testosterone-fatty acid ester pools were reduced in these organisms. These observations indicate that tributyltin elevates free testosterone by reducing the retention of testosterone as fatty acid-esters. This endocrine effect of tributyltin may be responsible for imposex.

  20. Methylmercury poisoning in the harp seal (Pagophilus groenlandicus)

    Energy Technology Data Exchange (ETDEWEB)

    Ronald, K [Univ. of Guelph, Ont.; Tessaro, S V; Uthe, J F; Freeman, H C; Frank, R

    1977-07-01

    Hematological and blood chemistry values were examined in harp seals (Pagophilus groenlandicus) exposed to daily oral dosages of methylmercuric chloride (MMC). Two seals, exposed to 0.25 mg MMC/kg body weight/day for 60 and 90 days, respectively, died not show abnormal blood values. Two other seals exposed to 25.0 mg MMC/kg body weight/day died on day 20 and 26 of exposure. Blood parameters indicated toxic hepatitis, uremia and renal failure. Total mercury and methylmercury values in the tissues of the experimental animals indicated that harp seals can tolerate high levels of mercury in the brain and that the observed renal and hepatic dysfunction were related to the high accumulation of mercury in these tissues. Tests of renal function are useful in cases of severe methylmercury poisoning.

  1. 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.

  2. The effects of the obesogen tributyltin on the metabolism of Sertoli cells cultured ex vivo.

    Science.gov (United States)

    Cardoso, Ana M; Alves, Marco G; Sousa, Ana C; Jarak, Ivana; Carvalho, Rui A; Oliveira, Pedro F; Cavaco, José E; Rato, Luís

    2018-02-01

    Human exposure to environmental contaminants is widespread. Some of these contaminants have the ability to interfere with adipogenesis, being thus considered as obesogens. Recently, obesogens have been singled out as a cause of male infertility. Sertoli cells (SCs) are essential for male fertility and their metabolic performance, especially glucose metabolism, is under a tight endocrine control, being essential for the success of spermatogenesis. Herein, we studied the impact of the model obesogen tributyltin in the metabolic profile of SCs. For that, ex vivo-cultured rat SCs were exposed to increasing doses of tributyltin. SCs proliferation was evaluated by the sulforhodamine B assay and the maturation state of the cells was assessed by the expression of specific markers (inhibin B and the androgen receptor) by quantitative polymerase chain reaction. The metabolic profile of SCs was established by studying metabolites consumption/production by nuclear magnetic resonance spectroscopy and by analyzing the expression of key transporters and enzymes involved in glycolysis by Western blot. The proliferation of SCs was only affected in the cells exposed to the highest dose (1000 nM) of tributyltin. Notably, SCs exposed to 10 nM tributyltin decreased the consumption of glucose and pyruvate, as well as the production of lactate. The decreased lactate production hampers the development of germ cells. Intriguingly, the lowest levels of tributyltin were more prone to modulate the expression of key players of the glycolytic pathway. This is the first study showing that tributyltin reprograms glucose metabolism of SCs under ex vivo conditions, suggesting new targets and mechanisms through which obesogens modulate the metabolism of SCs and thus male (in)fertility.

  3. Effect of tributyltin on mammalian endothelial cell integrity.

    Science.gov (United States)

    Botelho, G; Bernardini, C; Zannoni, A; Ventrella, V; Bacci, M L; Forni, M

    2015-01-01

    Tributyltin (TBT), is a man-made pollutants, known to accumulate along the food chain, acting as an endocrine disruptor in marine organisms, with toxic and adverse effects in many tissues including vascular system. Based on the absence of specific studies of TBT effects on endothelial cells, we aimed to evaluate the toxicity of TBT on primary culture of porcine aortic endothelial cells (pAECs), pig being an excellent model to study human cardiovascular disease. pAECs were exposed for 24h to TBT (100, 250, 500, 750 and 1000nM) showing a dose dependent decrease in cell viability through both apoptosis and necrosis. Moreover the ability of TBT (100 and 500nM) to influence endothelial gene expression was investigated at 1, 7 and 15h of treatment. Gene expression of tight junction molecules, occludin (OCLN) and tight junction protein-1 (ZO-1) was reduced while monocyte adhesion and adhesion molecules ICAM-1 and VCAM-1 (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) levels increased significantly at 1h. IL-6 and estrogen receptors 1 and 2 (ESR-1 and ESR-2) mRNAs, after a transient decrease, reached the maximum levels after 15h of exposure. Finally, we demonstrated that TBT altered endothelial functionality greatly increasing monocyte adhesion. These findings indicate that TBT deeply alters endothelial profile, disrupting their structure and interfering with their ability to interact with molecules and other cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Tributyltin Differentially Promotes Development of a Phenotypically Distinct Adipocyte

    Science.gov (United States)

    Regnier, Shane M.; El-Hashani, Essam; Kamau, Wakanene; Zhang, Xiaojie; Massad, Nicole L.; Sargis, Robert M.

    2015-01-01

    Objective Environmental endocrine disrupting chemicals (EDCs) are increasingly implicated in the pathogenesis of obesity. Evidence implicates various EDCs as being pro-adipogenic, including tributyltin (TBT), which activates the peroxisome proliferator activated receptor-γ (PPARγ). However, the conditions required for TBT-induced adipogenesis and its functional consequences are incompletely known. Methods The co-stimulatory conditions necessary for preadipocyte-to-adipocyte differentiation were compared between TBT and the pharmacological PPARγ agonist troglitazone (Trog) in the 3T3-L1 cell line; basal and insulin-stimulated glucose uptake were assessed using radiolabeled 2-deoxyglucose. Results TBT enhanced expression of the adipocyte marker C/EBPα with co-exposure to either isobutylmethylxanthine or insulin in the absence of other adipogenic stimuli. Examination of several adipocyte-specific proteins revealed that TBT and Trog differentially affected protein expression despite comparable PPARγ stimulation. In particular, TBT reduced adiponectin expression upon maximal adipogenic stimulation. Under submaximal stimulation, TBT and Trog differentially promoted adipocyte-specific gene expression despite similar lipid accumulation. Moreover, TBT attenuated Trog-induced adipocyte gene expression under conditions of co-treatment. Finally, TBT-induced adipocytes exhibited altered glucose metabolism, with increased basal glucose uptake. Conclusions TBT-induced adipocytes are functionally distinct from those generated by a pharmacological PPARγ agonist, suggesting that obesogen-induced adipogenesis may generate dysfunctional adipocytes with the capacity to deleteriously affect global energy homeostasis. PMID:26243053

  5. Differential susceptibility of brain regions to tributyltin chloride toxicity.

    Science.gov (United States)

    Mitra, Sumonto; Siddiqui, Waseem A; Khandelwal, Shashi

    2015-12-01

    Tributyltin (TBT), a well-known endocrine disruptor, is an omnipresent environmental pollutant and is explicitly used in many industrial applications. Previously we have shown its neurotoxic potential on cerebral cortex of male Wistar rats. As the effect of TBT on other brain regions is not known, we planned this study to evaluate its effect on four brain regions (cerebellum, hippocampus, hypothalamus, and striatum). Four-week-old male Wistar rats were gavaged with a single dose of TBT-chloride (TBTC) (10, 20, and 30 mg/kg) and sacrificed on days 3 and 7, respectively. Effect of TBTC on blood-brain barrier (BBB) permeability and tin (Sn) accumulation were measured. Oxidative stress indexes such as reactive oxygen species (ROS), reduced and oxidized glutathione (GSH/GSSG) ratio, lipid peroxidation, and protein carbonylation were analyzed as they play an imperative role in various neuropathological conditions. Since metal catalyzed reactions are a major source of oxidant generation, levels of essential metals like iron (Fe), zinc (Zn), and calcium (Ca) were estimated. We found that TBTC disrupted BBB and increased Sn accumulation, both of which appear significantly correlated. Altered metal homeostasis and ROS generation accompanied by elevated lipid peroxidation and protein carbonylation indicated oxidative damage which appeared more pronounced in the striatum than in cerebellum, hippocampus, and hypothalamus. This could be associated to the depleted GSH levels in striatum. These results suggest that striatum is more susceptible to TBTC induced oxidative damage as compared with other brain regions under study. © 2014 Wiley Periodicals, Inc.

  6. Deleterious effects of tributyltin on porcine vascular stem cells physiology.

    Science.gov (United States)

    Bernardini, Chiara; Zannoni, Augusta; Bertocchi, Martina; Bianchi, Francesca; Salaroli, Roberta; Botelho, Giuliana; Bacci, Maria Laura; Ventrella, Vittoria; Forni, Monica

    2016-01-01

    The vascular functional and structural integrity is essential for the maintenance of the whole organism and it has been demonstrated that different types of vascular progenitor cells resident in the vessel wall play an important role in this process. The purpose of the present research was to observe the effect of tributyltin (TBT), a risk factor for vascular disorders, on porcine Aortic Vascular Precursor Cells (pAVPCs) in term of cytotoxicity, gene expression profile, functionality and differentiation potential. We have demonstrated that pAVPCs morphology deeply changed following TBT treatment. After 48h a cytotoxic effect has been detected and Annexin binding assay demonstrated that TBT induced apoptosis. The transcriptional profile of characteristic pericyte markers has been altered: TBT 10nM substantially induced alpha-SMA, while, TBT 500nM determined a significant reduction of all pericyte markers. IL-6 protein detected in the medium of pAVPCs treated with TBT at both doses studied and with a dose response. TBT has interfered with normal pAVPC functionality preventing their ability to support a capillary-like network. In addition TBT has determined an increase of pAVPC adipogenic differentiation. In conclusion in the present paper we have demonstrated that TBT alters the vascular stem cells in terms of structure, functionality and differentiating capability, therefore effects of TBT in blood should be deeply explored to understand the potential vascular risk associated with the alteration of vascular stem cell physiology. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Tributyltin differentially promotes development of a phenotypically distinct adipocyte.

    Science.gov (United States)

    Regnier, Shane M; El-Hashani, Essam; Kamau, Wakanene; Zhang, Xiaojie; Massad, Nicole L; Sargis, Robert M

    2015-09-01

    Environmental endocrine disrupting chemicals (EDCs) are increasingly implicated in the pathogenesis of obesity. Evidence implicates various EDCs as being proadipogenic, including tributyltin (TBT), which activates the peroxisome proliferator activated receptor-γ (PPARγ). However, the conditions required for TBT-induced adipogenesis and its functional consequences are incompletely known. The costimulatory conditions necessary for preadipocyte-to-adipocyte differentiation were compared between TBT and the pharmacological PPARγ agonist troglitazone (Trog) in the 3T3-L1 cell line; basal and insulin-stimulated glucose uptake were assessed using radiolabeled 2-deoxyglucose. TBT enhanced expression of the adipocyte marker C/EBPα with coexposure to either isobutylmethylxanthine or insulin in the absence of other adipogenic stimuli. Examination of several adipocyte-specific proteins revealed that TBT and Trog differentially affected protein expression despite comparable PPARγ stimulation. In particular, TBT reduced adiponectin expression upon maximal adipogenic stimulation. Under submaximal stimulation, TBT and Trog differentially promoted adipocyte-specific gene expression despite similar lipid accumulation. Moreover, TBT attenuated Trog-induced adipocyte gene expression under conditions of cotreatment. Finally, TBT-induced adipocytes exhibited altered glucose metabolism, with increased basal glucose uptake. TBT-induced adipocytes are functionally distinct from those generated by a pharmacological PPARγ agonist, suggesting that obesogen-induced adipogenesis may generate dysfunctional adipocytes with the capacity to deleteriously affect global energy homeostasis. © 2015 The Obesity Society.

  8. Toxicity of tributyltin in the marine mollusc Mytilus edulis.

    Science.gov (United States)

    Hagger, Josephine A; Depledge, Michael H; Galloway, Tamara S

    2005-01-01

    Our previous studies have demonstrated that tributyltin (TBT) is genotoxic to the early life stages of marine mussels and worms. Here, the toxicity of TBT to adult organisms was determined using a suite of biomarkers designed to detect cytotoxic, immunotoxic and genotoxic effects. Exposure of adult mussels, Mytilus edulis, to environmentally realistic concentrations of TBTO for 7 days resulted in a statistically significant decrease in cell viability at concentrations of 0.5 microg/l and above. TBT had no effect on phagocytic activity or antioxidant capacity (FRAP assay). There was a statistically significant increase in DNA damage detected using the comet and micronucleus assays between the controls and 0.5, 1 and 5 microg/l of TBTO (P > 0.0005). Furthermore there was a strong correlation between DNA strand breaks (comet assay) and formation of micronuclei (P = 0.0005; R2 = 61.5%). Possible mechanisms by which TBT could damage DNA either directly or indirectly are discussed including the possibility that TBT is genotoxic due to its ability to disrupt calcium homeostasis.

  9. Tributyltin-induced apoptosis requires glycolytic adenosine trisphosphate production.

    Science.gov (United States)

    Stridh, H; Fava, E; Single, B; Nicotera, P; Orrenius, S; Leist, M

    1999-10-01

    The toxicity of tributyltin chloride (TBT) involves Ca(2+) overload, cytoskeletal damage, and mitochondrial failure leading to cell death by apoptosis or necrosis. Here, we examined whether the intracellular ATP level modulates the mode of cell death after exposure to TBT. When Jurkat cells were energized by the mitochondrial substrate, pyruvate, low concentrations of TBT (1-2 microM) triggered an immediate depletion of intracellular ATP followed by necrotic death. When ATP levels were maintained by the addition of glucose, the mode of cell death was typically apoptotic. Glycolytic ATP production was required for apoptosis at two distinct steps. First, maintenance of adequate ATP levels accelerated the decrease of mitochondrial membrane potential, and the release of the intermembrane proteins adenylate kinase and cytochrome c from mitochondria. A possible role of the adenine nucleotide exchanger in this first ATP-dependent step is suggested by experiments performed with the specific inhibitor, bongkrekic acid. This substance delayed cytochrome c release in a manner similar to that caused by ATP depletion. Second, caspase activation following cytochrome c release was only observed in ATP-containing cells. Bcl-2 had only a minor effect on TBT-triggered caspase activation or cell death. We conclude that intracellular ATP concentrations control the mode of cell death in TBT-treated Jurkat cells at both the mitochondrial and caspase activation levels.

  10. Cortical astrocytes exposed to tributyltin undergo morphological changes in vitro.

    Science.gov (United States)

    Mizuhashi, S; Ikegaya, Y; Nishiyama, N; Matsuki, N

    2000-11-01

    We investigated the effect of tributyltin (TBT), an endocrine-disrupting chemical, on the morphology and viability of cultured rat cortical astrocytes. Cultured astrocytes exhibited smooth and planiform morphology under normal conditions. Following exposure to TBT, however, they showed rapid morphological changes that are characterized by asteriated cell bodies and process formation in a time- and concentration-dependent manner. Higher concentrations of TBT produced progressive cell death of the astrocytes. In serum-free medium, TBT at a concentration as low as 200 nM induced the stellation. Pharmacological studies revealed that the morphological changes were alleviated by application of diverse free radical scavengers or antioxidants such as catalase, superoxide dismutase, Trolox, ascorbic acid and N-acetyl-L-cysteine, suggesting that TBT-induced stellation is caused by oxidative stress involving free radicals, particularly reactive oxygen species. Furthermore, we found that the astrocyte stellation was abolished by treatment with inhibitors of phospholipase C, mitogen-activated protein kinase kinase or tyrosine phosphatase. The data suggest that TBT causes the stellation through intracellular signaling cascades rather than its non-specific toxicity. These findings provide an important insight for reconciling the problems in assumed aversive actions of this environmental pollutant for mammals.

  11. Floodplain methylmercury biomagnification factor higher than that of the contiguous river (South River, Virginia USA)

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Michael C., E-mail: newman@vims.edu [College of William and Mary - VIMS, P.O. Box 1346, Rt. 1208 Greate Rd., Gloucester Point, VA 23062 (United States); Xu Xiaoyu, E-mail: xiaoyu@vims.edu [College of William and Mary - VIMS, P.O. Box 1346, Rt. 1208 Greate Rd., Gloucester Point, VA 23062 (United States); Condon, Anne, E-mail: anne_condon@fws.gov [U.S. Fish and Wildlife, 6669 Short Lane, Gloucester, VA 23061 (United States); Liang Lian, E-mail: liang@cebam.net [Cebam Analytical, Inc., 18804 North Creek Parkway, Suite 110, Bothell, WA 98011 (United States)

    2011-10-15

    Mercury biomagnification on the South River floodplain (Virginia, USA) was modeled at two locations along a river reach previously modeled for methylmercury movement through the aquatic trophic web. This provided an opportunity to compare biomagnification in adjoining trophic webs. Like the aquatic modeling results, methylmercury-based models provided better prediction than those for total mercury. Total mercury Food Web Magnification Factors (FWMF, fold per trophic level) for the two locations were 4.9 and 9.5. Methylmercury FWMF for the floodplain locations were higher (9.3 and 25.1) than that of the adjacent river (4.6). Previous speculation was not resolved regarding whether the high mercury concentrations observed in floodplain birds was materially influenced by river prey consumption by riparian spiders and subsequent spider movement into the trophic web of the adjacent floodplains. Results were consistent with a gradual methylmercury concentration increase from contaminated floodplain soil, to arthropod prey, and finally, to avian predators. - Highlights: > First comparison of methylmercury biomagnification in adjacent river/land food webs. > Methylmercury increased more rapidly in the terrestrial, than the aquatic, food web. > Methylmercury increased gradually from soil, to prey, and, to avian predators. - Higher methylmercury biomagnification on South River floodplain than the associated river likely explain high mercury in floodplain birds.

  12. Accumulation and elimination of methylmercury in Atlantic cod (Gadus morhua L.) following dietary exposure

    Energy Technology Data Exchange (ETDEWEB)

    Amlund, Heidi [National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, 5817 Bergen (Norway)]. E-mail: heidi.amlund@nifes.no; Lundebye, Anne-Katrine [National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, 5817 Bergen (Norway); Berntssen, Marc H.G. [National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, 5817 Bergen (Norway)

    2007-08-01

    Methylmercury is known to bioaccumulate and biomagnify up the marine food chain. Fish from high levels of the marine food chain may contain relatively high concentrations of mercury, and most (>70%) of the mercury found in muscle is methylmercury. In aquaculture, marine protein (mainly fishmeal) is the dominant source of methylmercury, and this raises some concern with regards to fish welfare and consumer safety. A dietary exposure study, including a depuration period, was carried out in order to study the accumulation and elimination of methylmercury in Atlantic cod (Gadus morhua L.), and to estimate the transfer of methylmercury from feed to fish. Fish were sampled throughout a three month exposure period and a three month depuration period. Muscle samples were fractionated into a protein and a lipid fraction by lipid extraction using methanol and chloroform. Mercury and methylmercury were determined by inductively coupled plasma mass spectrometry (ICPMS) and gas chromatography-inductively coupled plasma mass spectrometry (GC-ICPMS), respectively. A continuous accumulation of methylmercury, after a lag period of 10 days, was observed in muscle tissue during the three months exposure to methylmercury (0.95+/-0.03{mu}g Hg/g feed, n=6). After three months, the final concentration in muscle was 0.38+/-0.04{mu}g Hg/gww (n=6), where methylmercury constituted 90-95% of the mercury present. The elimination of methylmercury from muscle was slow and incomplete (within the three months of depuration) with an estimated elimination half-life (t{sub 1/2}) of 377 days. The transfer of methylmercury from feed to Atlantic cod, described by the estimated absorption efficiency, was 38%. In muscle more than 99% of the mercury was found in the protein fraction. These results suggest that Atlantic cod readily takes up dietary methylmercury, which is efficiently accumulated into muscle, where it is incorporated into larger peptides or proteins. Comparable results were found for

  13. Accumulation and elimination of methylmercury in Atlantic cod (Gadus morhua L.) following dietary exposure

    International Nuclear Information System (INIS)

    Amlund, Heidi; Lundebye, Anne-Katrine; Berntssen, Marc H.G.

    2007-01-01

    Methylmercury is known to bioaccumulate and biomagnify up the marine food chain. Fish from high levels of the marine food chain may contain relatively high concentrations of mercury, and most (>70%) of the mercury found in muscle is methylmercury. In aquaculture, marine protein (mainly fishmeal) is the dominant source of methylmercury, and this raises some concern with regards to fish welfare and consumer safety. A dietary exposure study, including a depuration period, was carried out in order to study the accumulation and elimination of methylmercury in Atlantic cod (Gadus morhua L.), and to estimate the transfer of methylmercury from feed to fish. Fish were sampled throughout a three month exposure period and a three month depuration period. Muscle samples were fractionated into a protein and a lipid fraction by lipid extraction using methanol and chloroform. Mercury and methylmercury were determined by inductively coupled plasma mass spectrometry (ICPMS) and gas chromatography-inductively coupled plasma mass spectrometry (GC-ICPMS), respectively. A continuous accumulation of methylmercury, after a lag period of 10 days, was observed in muscle tissue during the three months exposure to methylmercury (0.95+/-0.03μg Hg/g feed, n=6). After three months, the final concentration in muscle was 0.38+/-0.04μg Hg/gww (n=6), where methylmercury constituted 90-95% of the mercury present. The elimination of methylmercury from muscle was slow and incomplete (within the three months of depuration) with an estimated elimination half-life (t 1/2 ) of 377 days. The transfer of methylmercury from feed to Atlantic cod, described by the estimated absorption efficiency, was 38%. In muscle more than 99% of the mercury was found in the protein fraction. These results suggest that Atlantic cod readily takes up dietary methylmercury, which is efficiently accumulated into muscle, where it is incorporated into larger peptides or proteins. Comparable results were found for Atlantic salmon

  14. Recognizing and Preventing Overexposure to Methylmercury from Fish and Seafood Consumption: Information for Physicians

    Directory of Open Access Journals (Sweden)

    Susan M. Silbernagel

    2011-01-01

    Full Text Available Fish is a valuable source of nutrition, and many people would benefit from eating fish regularly. But some people eat a lot of fish, every day or several meals per week, and thus can run a significant risk of overexposure to methylmercury. Current advice regarding methylmercury from fish consumption is targeted to protect the developing brain and nervous system but adverse health effects are increasingly associated with adult chronic low-level methylmercury exposure. Manifestations of methylmercury poisoning are variable and may be difficult to detect unless one considers this specific diagnosis and does an appropriate test (blood or hair analysis. We provide information to physicians to recognize and prevent overexposure to methylmercury from fish and seafood consumption. Physicians are urged to ask patients if they eat fish: how often, how much, and what kinds. People who eat fish frequently (once a week or more often and pregnant women are advised to choose low mercury fish.

  15. Effects of Prenatal Methylmercury Exposure: From Minamata Disease to Environmental Health Studies.

    Science.gov (United States)

    Sakamoto, Mineshi; Itai, Takaaki; Murata, Katsuyuki

    2017-01-01

    Methylmercury, the causative agent of Minamata disease, can easily penetrate the brain, and adult-type Minamata disease patients showed neurological symptoms according to the brain regions where the neurons, mainly in the cerebrum and cerebellum, were damaged. In addition, fetuses are exposed to methylmercury via the placenta from maternal fish consumption, and high-level exposure to methylmercury causes damage to the brains of infants. Typical patients with fetal-type Minamata disease (i.e., serious poisoning caused by in utero exposure to methylmercury) were born during the period of severe methylmercury pollution in 1955-1959, although they showed no abnormality during gestation nor at delivery. However, they showed difficulties in head control, sitting, and walking, and showed disturbances in mental development, these symptoms that are similar to those of cerebral palsy, during the growth periods after birth. The impaired development of fetal-type Minamata disease patients was one of the most tragic and characteristic feature of Minamata disease. In this review, we first summarize 1) the effects of prenatal methylmercury exposure in Minamata disease. Then, we introduce the studies that were conducted mainly by Sakamoto et al. as follows: 2) a retrospective study on temporal and regional variations of methylmercury pollution in Minamata area using preserved umbilical cord methylmercury, 3) decline in male sex ratio observed in Minamata area, 4) characteristics of hand tremor and postural sway in fetal-type Minamata disease patients, 5) methylmercury transfer from mothers to infants during gestation and lactation (the role of placenta), 6) extrapolation studies using rat models on the effects of prenatal methylmercury exposure on the human brain, and 7) risks and benefits of fish consumption.

  16. Effects of TBT (Tributyltin) on Marine Organisms: Field Assessment of a New Site-Specific Bioassay System.

    Science.gov (United States)

    1987-12-01

    evaluated in San Diego Bay over a 7-month period using tributyltin ( TBT ) antifouling leachates. Three TBT concentrations (k = 0.065, 0.077 and 0.193 ug...tional value and epifaunal organisms and 2) test using tributyltin (TT) antifouling leachates. the efficacy of the PETS. The results of the TBT Three...Conoentrations of 0.200, study the effects of tributyltin (TBI), the primary 0.050 and 0.020 ug/l, respectively. Unfiltered toxic component of organotin AF

  17. Tributyltin exposure alters cytokine levels in mouse serum.

    Science.gov (United States)

    Lawrence, Shanieek; Pellom, Samuel T; Shanker, Anil; Whalen, Margaret M

    2016-11-01

    Tributyltin (TBT), a toxic environmental contaminant, has been widely utilized for various industrial, agricultural and household purposes. Its usage has led to a global contamination and its bioaccumulation in aquatic organisms and terrestrial mammals. Previous studies suggest that TBT has debilitating effects on the overall immune function of animals, rendering them more vulnerable to diseases. TBT (at concentrations that have been detected in human blood) alters secretion of inflammatory cytokines from human lymphocytes ex vivo. Thus, it is important to determine if specified levels of TBT can alter levels of cytokines in an in vivo system. Mice were exposed to biologically relevant concentrations of TBT (200, 100 or 25 nM final concentrations). The quantitative determination of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL2, IL5, IL7, IL12βp40, IL13, IL15, keratinocyte chemoattractant (KC), macrophage inflammatory protein 1β (MIP), MIP2 and regulated on activation normal T-cell-expressed and secreted (RANTES) was performed in mouse sera by MAGPIX analysis and Western blot. Results indicated alterations (both decreases and increases) in several cytokines. The pro-inflammatory cytokines IFNγ, TNFα, IL-1β, IL-2, IL5, IL12βp40 and IL-15 were altered as were the chemokines MIP-1 and RANTES and the anti-inflammatory cytokine IL-13. Increases in IFNγ and TNFα were seen in the serum of mice exposed to TBT for less than 24 h. Levels of IL1β, IL-12 βp40, IL-5 and IL-15 were also modulated in mouse serum, depending on the specific experiment and exposure level. IL-2 was consistently decreased in mouse serum when animals were exposed to TBT. There were also TBT-induced increases in MIP-1β, RANTES and IL-13. These results from human and murine samples clearly suggest that TBT exposures modulate the secretion inflammatory cytokines.

  18. Tributyltin-resistant bacteria from estuarine and freshwater sediments.

    Science.gov (United States)

    Wuertz, S; Miller, C E; Pfister, R M; Cooney, J J

    1991-01-01

    Resistance to tributyltin (TBT) was examined in populations from TBT-polluted sediments and nonpolluted sediments from an estuary and from fresh water as well as in pure cultures isolated from those sediments. The 50% effective concentrations (EC50s) for populations were higher at a TBT-polluted freshwater site than at a site without TBT, suggesting that TBT selected for a TBT-resistant population. In contrast, EC50s were significantly lower for populations from a TBT-contaminated estuarine site than for those from a site without TBT, suggesting that other factors in addition to TBT determine whether populations become resistant. EC50s for populations from TBT-contaminated freshwater sediments were nearly 30 times higher than those for populations from TBT-contaminated estuarine sediments. We defined a TBT-resistant bacterium as one which grows on trypticase soy agar containing 8.4 microM TBT, a concentration which prevented the growth of 90% of the culturable bacteria from these sediments. The toxicity of TBT in laboratory media was influenced markedly by the composition of the medium and whether it was liquid or solid. Ten TBT-resistant isolates from estuarine sediments and 19 from freshwater sediments were identified to the genus level. Two isolates, each a Bacillus sp., may be the first gram-positive bacteria isolated from fresh water in the presence of a high concentration of TBT. There was a high incidence of resistance to heavy metals: metal resistance indices were 0.76 for estuarine isolates and 0.68 for freshwater isolates.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1746939

  19. Tributyltin Exposure Alters Cytokine Levels in Mouse Serum

    Science.gov (United States)

    Lawrence, Shanieek; Pellom, Samuel T.; Shanker, Anil; Whalen, Margaret M.

    2016-01-01

    Tributyltin (TBT), a toxic environmental contaminant, has been widely utilized for various industrial, agricultural and household purposes. Its usage has led to a global contamination and its bioaccumulation in aquatic organisms and terrestrial mammals. Previous studies suggest that TBT has debilitating effects on the overall immune function of animals, rendering them more vulnerable to diseases. TBT (at concentrations that have been detected in human blood) alters secretion of inflammatory cytokines from human lymphocytes ex vivo. Thus, it is important to determine if specified levels of TBT can alter levels of cytokines in an in vivo system. Mice were exposed to biologically relevant concentrations of TBT (200, 100 or 25 nM final concentrations). The quantitative determination of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL2, IL5, IL7, IL12βp40, IL13, IL15, KC, MIP1β, MIP2 and RANTES was performed in mouse sera by MAGPIX analysis and Western blot. Results indicated alterations (both decreases and increases) in several cytokines. The pro-inflammatory cytokines IFNγ, TNFα, IL-1β, IL-2, IL5, IL12βp40, and IL-15 were altered as were the chemokines MIP-1 and RANTES and the anti-inflammatory cytokine IL-13. Increases in IFNγ and TNFα were seen in serum of mice exposed to TBT for less than 24 hr. IL1-β, IL-12βp40, IL-5 and IL-15 were also modulated in mouse serum depending on the specific experiment and the exposure concentration. IL-2 was consistently decreased in mouse serum when animals were exposed to TBT. There were also TBT-induced increases in MIP-1β, RANTES, and IL-13. These results from human and murine samples clearly suggest that TBT exposures modulate the secretion inflammatory cytokines. PMID:27602597

  20. Organotins and new antifouling biocides in water and sediments from three Korean Special Management Sea Areas following ten years of tributyltin regulation: Contamination profiles and risk assessment.

    Science.gov (United States)

    Lam, Nguyen Hoang; Jeong, Hui-Ho; Kang, Su-Dong; Kim, Dae-Jin; Ju, Mi-Jo; Horiguchi, Toshihiro; Cho, Hyeon-Seo

    2017-08-15

    A simultaneous monitoring study on organotins (butyltins and phenyltins) and most frequently used alternative antifouling biocides (Irgarol 1051, Diuron, Sea-Nine 211 and M1) in water and sediments (n=44) collected from three Special Management Sea Areas operated by Korean government. The lower concentration of butyltins (BTs) than that of new antifouling biocides (NEW) was found in water but the significant greater concentration of BTs than that of NEW was still found in sediments. The tributyltin (TBT) levels in water exceeded the chronic criterion to protect seawater aquatic life at several sites. Even ten years after the ban of the use of TBT-based antifouling paint, the concentrations of TBT, Diuron and Irgarol 1051 in sediments from shipyards exceeded global sediment quality guidelines and potentially poses adverse risks on marine organisms and extremely high concentration of TBT up to 2304ng/g was found for a sediment collected at a shipyard. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Factors affecting the toxicity of methylmercury injected into eggs

    Science.gov (United States)

    Heinz, G.H.; Hoffman, D.J.; Kondrad, S.L.; Erwin, C.A.

    2006-01-01

    We developed a standardized protocol for comparing the sensitivities of the embryos of different bird species to methylmercury when methylmercury was injected into their eggs. During the course of developing this protocol, we investigated the effects of various factors on the toxicity of the injected methylmercury. Most of our experiments were done with chicken (Gallus domesticus), mallard (Anas platyrhynchos), and ring-necked pheasant (Phasianus colchicus) eggs, all of which were purchased in large numbers from game farms. A smaller amount of work was done with double-crested cormorant (Phalacrocorax auritus) eggs collected from the wild. Several solvents were tested, and corn oil at a rate of 1 :l/g egg contents was selected for the final standardized protocol because it had minimal toxicity to embryos and because methylmercury dissolved in corn oil yielded a dose?response curve in a range of egg concentrations that was similar to the range that causes reproductive impairment when the mother deposits methylmercury into her own eggs. The embryonic stage at which eggs were injected with corn oil altered mercury toxicity; at early stages, the corn oil itself was toxic. Therefore, in the final protocol we standardized the time of injection to occur when each species reached the morphologic equivalent of a 3-day-old chicken embryo. Although solvents can be injected directly into the albumen of an egg, high embryo mortality can occur in the solvent controls because of the formation of air bubbles in the albumen. Our final protocol used corn oil injections into the air cell, which are easier and safer than albumen injections. Most of the methylmercury, when dissolved in corn oil, injected into the air cell passes through the inner shell membrane and into the egg albumen. Most commercial incubators incubate eggs in trays with the air cell end of the egg pointing upward, but we discovered that mercury-induced mortality was too great when eggs were held in this orientation

  2. Collaborative evaluation of methods for tributyltin determinations in sediment and mussel tissue

    NARCIS (Netherlands)

    Quevauviller, P.; Astruc, M.; Morabito, R.; Ariese, F.; Ebdon, L.

    2000-01-01

    Tributyltin (TBT) is widespread in the marine environment owing to its release from antifouling paints and its monitoring is mandatory under national and EC regulations. Many hyphenated techniques have been developed within the last 15 years and collaborative efforts were deemed necessary to

  3. Diversity and community composition of tributyltin-resistant bacteria under different conditions

    International Nuclear Information System (INIS)

    Lee, Y. H.; Park, S.; Park, H.; Choi, Y

    2009-01-01

    Tributyltin (TBT) is an organometallic compound used as anti fouling agent in marine paints. this compound is toxic not only for eukaryotes, but also for bacteria. Based on the literature review, a few researchers have reported evidence for the presence of TBT-resistant bacteria in natural seawater and marine sediment. (Author)

  4. Diversity and community composition of tributyltin-resistant bacteria under different conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Park, S.; Park, H.; Choi, Y

    2009-07-01

    Tributyltin (TBT) is an organometallic compound used as anti fouling agent in marine paints. this compound is toxic not only for eukaryotes, but also for bacteria. Based on the literature review, a few researchers have reported evidence for the presence of TBT-resistant bacteria in natural seawater and marine sediment. (Author)

  5. LIFE-CYCLE TOXICITY OF BIS(TRIBUTYLTIN) OXIDE TO THE SHEEPSHEAD MINNOW (CYPRINODON VARIEGATUS)

    Science.gov (United States)

    The effects of tributyltin (TBT) to the life cycle of the estuarine fish C yprinodon variegatus were examined in a 180-day flow-through exposure. The study was initiated with embryos less than 24 h postfertilization and monitored through hatch, maturation, growth, and reproductio...

  6. Radioactive intermediate products in the photolysis of the system [1-14C] tributyltin oxide cellulose

    International Nuclear Information System (INIS)

    Kloetzer, D.

    1982-01-01

    Interactions between matrix and applied biocide in the photochemical degradation of the system [1- 14 C] tributyltin oxide/cellulose have been investigated. The intermediate formation of [1- 14 C] tributylstannyl cellulose ethers was found to be the most important step. The photochemical preparation of bis [8- 14 C] tributylstannyl glucose ether is described. (author)

  7. Carboxylate derivatives of tributyltin (IV) complexes as anticancer and antileishmanial agents.

    Science.gov (United States)

    Waseem, Durdana; Butt, Arshad Farooq; Haq, Ihsan-Ul; Bhatti, Moazzam Hussain; Khan, Gul Majid

    2017-04-04

    Tributyltin (IV) compounds are promising candidates for drug development. In the current study, we evaluated in-vitro and in-silico profile of carboxylate derivatives of tributyltin (IV) complexes. ADMET and drug-likeliness properties were predicted using MetaPrint2D React, preADMET, SwissADME and Molsoft tools. SwissTargetPrediction predicted molecular targets for compounds. In-vitro bioactivity was evaluated by quantifying cytotoxicity against HepG2, THP-1 cell lines, isolated lymphocytes and leishmania promastigotes as well as measuring protein kinase (PK) inhibition activity. Results indicate partial compliance of compounds with drug-likeliness rules. Ch-409 complies with WDI and Lipinski rules. ADMET profile prediction shows strong plasma protein binding except for Ch-409, low to high GI absorption and BBB penetration (C brain /C blood  = 0.942-11; caco-2 cells permeability 20.13-26.75 nm/sec), potential efflux by P-glycoprotein, metabolism by CYP3A4, medium inhibition of hERG, mutagenicity and capacity to be detoxified by glutathionation and glucuronidation. Molecular targets include proteases, enzymes, membrane receptors, transporters and ion channels where Ch-409 targets membrane receptors only. Compounds are significantly (p tributyltin (IV) complexes possess significant antileishmanial and cytotoxic potential. These are promising compounds for the development of antileishmanial and anticancer drugs. Graphical Abstract Carboxylate derivatives of tributyltin (IV) complexes as anticancer and antileishmanial agents.

  8. Termite and fungal resistance of in situ polymerized tributyltin acrylate and acetylated Indonesian and USA wood

    Science.gov (United States)

    Rebecca E. Ibach; Yusuf Sudo Hadi; Dodi Nandika; Sulaeman Yusuf; Yuliati Indrayani

    2000-01-01

    Wood [Indonesian pine (IP), Indonesian Jabon (IJ) and USA southern yellow pine (USP)] was either in situ polymerized with tributyltin acrylate (TBTA) or acetylated and then exposed to termite and fungal degradation both in laboratory tests and field exposure. The TBTA woods had an average weight percent gain (WPG) of 11% for IP, 12% for IJ, and 10% for USP. The...

  9. The US EPA reference dose for methylmercury: sources of uncertainty

    International Nuclear Information System (INIS)

    Rice, D.C.

    2004-01-01

    The US Environmental Protection Agency (EPA) derived a reference dose for methylmercury in 2001, based on an extensive analysis by the National Research Council (NRC) of the National Academy of Sciences. The NRC performed benchmark dose analysis on a number of endpoints from three longitudinal prospective studies: the Seychelles Islands, the Faroe Islands, and the New Zealand studies. Adverse effects were reported in the latter two studies, but not in the Seychelles study. The NRC also performed an integrative analysis of all three studies. Dose conversion from cord blood or maternal hair mercury concentration was performed by EPA using a one-compartment pharmacokinetic model. A total uncertainty factor of 10 was applied for intrahuman pharmacokinetic and pharmacodynamic variability. There are numerous decisions made by the NRC/EPA that could greatly affect the value of the reference dose (RfD). Some of these include the choice of a linear model for the relationship between mercury body burden and neuropsychological performance, the choice of values of P 0 and the benchmark response, the use of the 'critical study/critical endpoint' approach in the interpretation of the maternal body burden that corresponds to the RfD, the use of central tendencies in a one-compartment pharmacokinetic model rather than the inclusion of the distributions of variables for the population of reproductive-age women, the assumption of unity for the ratio of fetal cord blood to maternal blood methylmercury concentrations, the choice of a total of 10 as an uncertainty factor, and the lack of dose-response analysis for other health effects such as cardiovascular disease. In addition, it may be argued that derivation of a RfD for methylmercury is inappropriate, given that there does not appear to be a threshold for adverse neuropsychological effects based on available data

  10. Report on the methylmercury situation in Par Pond. Final report

    International Nuclear Information System (INIS)

    Schindler, J.E.; Williams, D.J.; Alberts, J.J.

    1975-06-01

    Studies are reported on the methylation and accumulation of mercury in fish populations of the pond. Results showed that the majority of the mercury in the fish muscles was in the methyl mercury form. Very low concentrations of mercury were found in the pond sediments. Physiological methylation of the mercury could not be demonstrated by in vivo or in vitro techniques. Organic ligand methylation and reduction of the mercury was shown to be a possible mechanism to account for both the mercury distribution in the pond and the concentrations of methylmercury in the fish. Recommendations are made for remedial treatments to eliminate the mercury problem. (HLW)

  11. Improved understanding of tributyltin sorption on natural and biochar-amended sediments.

    Science.gov (United States)

    Xiao, Xiaoyu; Sheng, G Daniel; Qiu, Yuping

    2011-12-01

    A poor understanding of tributyltin (TBT) sorption on sediments has hindered an accurate evaluation of its environmental fate. The present study determined TBT sorption by a freshwater sediment (BH) and a coastal marine sediment (TZ) as influenced by pH, salinity, and biochar (BC) amendment into TZ. The isotherms were essentially linear, with K(OC) values in the range of 10(4) to 10(5) L/kg. Tributyltin sorption at pH 3.56 and 8.00 occurred mainly via partitioning. It reached maxima at pH equal to its pK(a) (=6.25) because of added ion exchange. A salinity increase from 5 to 35 practical salinity units enhanced TBT sorption at pH 3.56 and 8.00 on TZ by approximately 30% and on BH by approximately 80%, ascribed to the salting-out effect that reduced the solubilities of tributyltin hydroxide (TBTOH) and tributyltin chloride (TBTCl). At pH 6.25, the same salinity increase reduced TBT sorption on TZ by approximately 20% but enhanced TBT sorption on BH by approximately 35%. This was attributed to the enhancing role of salting out and the reducing role of metal competition for ion exchange. Tributyltin was two orders of magnitude more effectively sorbed by BC than by total organic carbon of TZ, mainly because of the high level of surface area of the BC. Although BC affinity for TBT may be significantly diminished when present in TZ, it was considered to be the primary contributor to TBT sorption from water. Biochar may thus be used to immobilize TBT in sediment for potential remediation. Copyright © 2011 SETAC.

  12. Effects of tributyltin (TBT) and testosterone on the female genital system in the mesogastropod Littorina littorea (Prosobranchia)

    Science.gov (United States)

    Deutsch, U.; Fioroni, P.

    1996-03-01

    Experiments were performed with the mesogastropod Littorina littorea on Helgoland, in Roscoff, and in the laboratory in order to evaluate the reaction of the female genital system to TBT, an environmental toxicant. The snails were either injected with 50 or 100 ng tributyltin (TBT) soluted in ethanol or exposed to artificial sea water treated with 5, 50, 100, and 200 ng TBT/l, and 33 ng testosterone/l. The duration of the experiments was either four or eight weeks. None of the analysed female L. littorea showed signs of imposex. Compared to results for the control groups, the size of the female glandular complex was significantly reduced if the pre-experimental toxication was already high, as is the case in snails collected around Helgoland. TBT-related gland complex reduction occurs also in female L. littorea from other sampling sites. In addition, injection of ethanol also causes a decrease in gland size. The experimental results demonstrate that the distal female genital system responds with significantly lower sensitivity to TBT than that of other prosobranchs. This behaviour is ascribed to the lack of an androgen receptor at the ovipositor. The results further strengthen the case of the extreme rarity of imposex described for female L. littorea in natural habitats. However, strong TBT-toxication may affect L. littorea populations significantly because of increasing masculinization of the females, which reduces reproduction ability.

  13. Voltammetric studies on the electrochemical determination of methylmercury in chloride medium at carbon microelectrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, F. [Centro de Electroquimica e Cinetica da Universidade de Lisboa, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisbon (Portugal); Neto, M.M.M. [Centro de Electroquimica e Cinetica da Universidade de Lisboa, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisbon (Portugal) and Departamento de Quimica Agricola e Ambiental, Instituto Superior de Agronomia, Tapada da Ajuda, 1349-017 Lisbon (Portugal)]. E-mail: mm.neto@netcabo.pt; Rocha, M.M. [Centro de Electroquimica e Cinetica da Universidade de Lisboa, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisbon (Portugal); Fonseca, I.T.E. [Centro de Electroquimica e Cinetica da Universidade de Lisboa, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisbon (Portugal)

    2006-10-10

    Electroanalytical techniques have been used to determine methylmercury at low levels in environmental matrices. The electrochemical behaviour of methylmercury at carbon microelectrodes in a hydrochloric acid medium using cyclic, square wave and fast-scan linear-sweep voltammetric techniques has been investigated. The analytical utility of the methylmercury reoxidation peak has been explored, but the recorded peak currents were found to be poorly reproducible. This is ascribed to two factors: the adsorption of insoluble chloromercury compounds on the electrode surface, which appears to be an important contribution to hinder the voltammetric signal of methylmercury; and the competition between the reoxidation of the methylmercury radical and its dimerization reaction, which limits the reproducibility of the methylmercury peak. These problems were successfully overcome by adopting the appropriate experimental conditions. Fast-scan rates were employed and an efficient electrochemical regeneration procedure of the electrode surface was achieved, under potentiostatic conditions in a mercury-free solution containing potassium thiocyanate-a strong complexing agent. The influence of chloride ion concentration was analysed. Interference by metals, such as lead and cadmium, was considered. Calibration plots were obtained in the micromolar and submicromolar concentration ranges, allowing the electrochemical determination of methylmercury in trace amounts. An estuarine water sample was analysed using the new method with a glassy carbon microelectrode.

  14. Effects of Methylmercury exposure in 3T3-L1 Adipocytes

    Directory of Open Access Journals (Sweden)

    Theresa Vertigan

    2017-02-01

    Full Text Available Mercury-containing compounds are environmental pollutants that have become increasingly consequential in the Arctic regions of North America due to processes of climate change increasing their release and availability at northern latitudes. Currently, the form of mercury known to be most detrimental to human health is methylmercury, CH3Hg+, which is found in the environment and accumulates in the tissues of piscivores, including those consumed by Alaska Natives through subsistence gathering. Much is known about the neurotoxicity of methylmercury after exposure to high concentrations, but little is known about toxicity to other tissues and cell types, particularly for long-term exposure and the lower concentrations that would occur through fish consumption. Effects of methylmercury exposure on 3T3-L1 adipocytes in culture were assessed using assays for cytotoxicity and an ELISA assay for vascular endothelial growth factor (VEGF, a signaling molecule shown to be important for maintaining metabolic status in adipose tissue. Results showed that exposure to methylmercury leads to significant toxicity in adipocytes at exposures of 100 ng/mL during later stages of differentiation, but lower methylmercury concentrations produced little to no toxicity. Results also showed that VEGF secretion is elevated in adipocytes exposed to methylmercury after the process of differentiating into mature, fat-storing cells. These results provide a basis for further exploration into metabolic consequences of methylmercury exposure on specific cell types and cell models.

  15. Voltammetric studies on the electrochemical determination of methylmercury in chloride medium at carbon microelectrodes

    International Nuclear Information System (INIS)

    Ribeiro, F.; Neto, M.M.M.; Rocha, M.M.; Fonseca, I.T.E.

    2006-01-01

    Electroanalytical techniques have been used to determine methylmercury at low levels in environmental matrices. The electrochemical behaviour of methylmercury at carbon microelectrodes in a hydrochloric acid medium using cyclic, square wave and fast-scan linear-sweep voltammetric techniques has been investigated. The analytical utility of the methylmercury reoxidation peak has been explored, but the recorded peak currents were found to be poorly reproducible. This is ascribed to two factors: the adsorption of insoluble chloromercury compounds on the electrode surface, which appears to be an important contribution to hinder the voltammetric signal of methylmercury; and the competition between the reoxidation of the methylmercury radical and its dimerization reaction, which limits the reproducibility of the methylmercury peak. These problems were successfully overcome by adopting the appropriate experimental conditions. Fast-scan rates were employed and an efficient electrochemical regeneration procedure of the electrode surface was achieved, under potentiostatic conditions in a mercury-free solution containing potassium thiocyanate-a strong complexing agent. The influence of chloride ion concentration was analysed. Interference by metals, such as lead and cadmium, was considered. Calibration plots were obtained in the micromolar and submicromolar concentration ranges, allowing the electrochemical determination of methylmercury in trace amounts. An estuarine water sample was analysed using the new method with a glassy carbon microelectrode

  16. The determination of methylmercury, total mercury and total selenium in human hair

    International Nuclear Information System (INIS)

    1987-01-01

    This Reference Method describes the determination of methylmercury in human hair by gas liquid chromatography. It is designed for biological monitoring of selected individuals and population groups with a possible intake of methylmercury exceeding the recommended Provisional Tolerable Weekly Intake (PTWI) through contaminated seafood, as part of a project on the evaluation of methylmercury in Mediterranean populations and related health hazards. The method, however, is also applicable to other regions. The method involves direct determination of methylmercury by gas liquid chromatography. The sample is disintegrated in a solution of sodium hydroxide, methylmercury is extracted from an aliquot of the solution into toluene and, after purification, a small volume is injected into a chromatographic column, filled with polyethyleneglycol succinate on Diatomite AW. Methylmercury in the gaseous mixture is detected with an electron capture detector and its amount determined by comparing the peak height with those of appropriate standards. The next Reference Method describes the determination of selenium in human hair (and other indicative tissues) by gas liquid chromatography and is designed for biological monitoring of selected individuals and population groups in the Mediterranean region with a possible intake of methylmercury exceeding the recommended Provisional Tolerable Weekly Intake (PTWI) through contaminated seafood. The data are intended to establish a possible correlation between methylmercury intake and levels of selenium in the subjects monitored. Selenium in the solvent phase is determined by gas liquid chromatography using an electron capture detector. The above method has been selected because selenium is determined in conjunction with methylmercury, both of which require competence in gas chromatographic techniques. Reliable result for total selenium, however, will also be obtained by the following techniques: a) Atomic absorption spectrophotometry; b

  17. Removal of tributyltin from contaminated seawater by combinations of photolytic and TiO2 mediated photocatalytic processes

    DEFF Research Database (Denmark)

    Muff, Jens; Simonsen, Morten Enggrob; Søgaard, Erik Gydesen

    2017-01-01

    Harbour sediment contaminated with tributyltin (TBT) is a worldwide problem and treatment of TBT contaminated seawater is an issue during dredging operations. This study presents results from photolytic and photocatalytic treatment experiments where the influence of the seawater matrix, different...

  18. THE BIOCIDE TRIBUTYLTIN REDUCES THE ACCUMULATION OF TESTOSTERONE AS FATTY ACID ESTERS IN THE MUD SNAIL (ILYANASSA OBSOLETA)

    Science.gov (United States)

    Imposex, the development of male sex characteristics by female gonochoristic snails, has been documented globally and is causally associated with exposure to the ubiquitous environmental contaminant tributyltin (TBT). Elevated testosterone levels in snails also are associated wit...

  19. THE BIOCIDE TRIBUTYLTIN REDUCES THE RETENTION OF TESTOSTERONE AS FATTY ACID ESTERS IN THE MUD SNAIL (ILYANASSA OBSOLETA)

    Science.gov (United States)

    ABSTRACT Imposex, the development of male sex characteristics by female gonochoristic snails, has been causally associated with exposure to the ubiquitous environmental contaminant tributyltin (TBT). Documentation of imposex distribution indicates that this masculinizat...

  20. DECREASED RESISTANCE OF EASTERN OYSTERS (CRASSOSTREA VIRGINICA) TO A PROTOZOAN PATHOGEN (PERKINSUS MARINUS) AFTER SUBLETHAL EXPOSURE TO TRIBUTYLTIN OXIDE

    Science.gov (United States)

    Anthropogenic environmental stress is a likely contributor to outbreaks of disease due to immunosuppression or increased host vulnerability. Estuarine organisms are exposed to variable concentrations of marine antifouling agents, such as tributyltin (TBT), with higher exposures e...

  1. Hair methylmercury levels of mummies of the Aleutian Islands, Alaska

    International Nuclear Information System (INIS)

    Egeland, G.M.; Ponce, Rafael; Bloom, Nicolas S.; Knecht, Rick; Loring, Stephen; Middaugh, John P.

    2009-01-01

    Ancient human hair specimens can shed light on the extent of pre-historic exposures to methylmercury and provide valuable comparison data with current-day exposures, particularly for Indigenous Peoples who continue to rely upon local traditional food resources. Human hair from ancient Aleutian Island Native remains were tested for total and methylmercury (Hg, MeHg) and were radiocarbon dated. The remains were approximately 500 years old (1450 A.D.). For four adults, the mean and median total hair mercury concentration was 5.8 ppm (SD=0.9). In contrast, MeHg concentrations were lower with a mean of 1.2 ppm (SD=1.8) and a median of 0.54 ppm (0.12-3.86). For the five infants, the mean and median MeHg level was 1.2 ppm (SD=1.8) and 0.20 ppm (0.007-4.61), respectively. Segmental analyses showed variations in MeHg concentrations in 1-cm segments, consistent with fluctuations in naturally occurring exposure to mercury through dietary sources. The levels are comparable to or lower than those found in fish and marine mammal-eating populations today who rely far less on subsistence food than pre-historic humans. The findings are, therefore, compatible with increased anthropogenic release of trace metals during the past several centuries

  2. Effects of dietary methylmercury on ring-necked pheasants

    Energy Technology Data Exchange (ETDEWEB)

    Fimreite, N

    1971-01-01

    The effects of methylmercury-treated grain (methylmercury dicyandiamide) on penned pheasants (Phasianus colchicus) were studied. No weight reduction in the adult birds could be ascribed to the mercury compound. Compared to the controls, mortality was lower than average in the groups that received a mercury-contaminated diet throughout the experiment, suggesting a possible therapeutic effect of mercury. Food consumption was affected only in the group that received the largest amounts of mercury. Some of the hens receiving the greatest amounts of mercury exhibited extensive demyelination of the spinal cord. Strong adverse effects on reproduction were found: the most important indication was reduced hatchability, followed by a reduced egg production and a large number of shell-less eggs. Chick survival was comparatively less affected. Egg weight was reduced significantly in most of the experimental groups, especially during the last weeks of the experiment, and the highest mercury levels produced a large number of eggs with abnormal color. 16 references, 8 figures, 9 tables.

  3. Prenatal methylmercury exposure affects spatial vision in adult monkeys

    International Nuclear Information System (INIS)

    Burbacher, Thomas M.; Grant, Kimberly S.; Mayfield, David B.; Gilbert, Steven G.; Rice, Deborah C.

    2005-01-01

    Decades of research have demonstrated that exposure to methylmercury (MeHg), a ubiquitous environmental pollutant, can have both early and long-term neurobehavioral consequences in exposed offspring. The present study assessed visual functioning in adult macaque monkeys (Macaca fascicularis) exposed in utero to 0, 50, 70, or 90 μg/kg/day of MeHg hydroxide. Twenty-one full-term, normal birth weight offspring (9 controls, 12 exposed) were tested at approximately 11-14.5 years of age on a visual contrast sensitivity task. A forced-choice tracking procedure was utilized with spatial frequencies of 1, 4, 10, and 20 cycles per degree of visual angle. On each test session, a single spatial frequency was presented across five levels of contrast, each differing by 3 dB. Methylmercury-exposed monkeys exhibited reduced contrast sensitivity thresholds, particularly at the higher spatial frequencies. The degree of visual impairment was not related to MeHg body burden or clearance and almost half of the exposed animals were unimpaired. The results from this study demonstrate that chronic in utero MeHg exposure, at subclinical levels, is associated with permanent adverse effects on spatial vision in adult monkeys

  4. Predictive models of benthic invertebrate methylmercury in Ontario and Quebec lakes

    Energy Technology Data Exchange (ETDEWEB)

    Rennie, M.D.; Collins, N.C.; Purchase, C.F. [Toronto Univ., ON (Canada). Dept. of Biology; Tremblay, A. [Hydro-Quebec, Montreal, PQ (Canada)

    2005-12-01

    In both North America and Europe, high levels of mercury have been reported in lakes that do not receive obvious point-source mercury inputs. Concern over high contaminant levels in waterfowl and fish have prompted several government-issued advisories on safe levels of fish and wildlife intake for humans. Although the primary source of mercury in pristine lakes is directly through atmospheric deposition or indirectly via terrestrial runoff, there can be large variations in mercury concentrations in organisms in neighbouring lakes. Therefore, factors other than atmospheric deposition must influence bioavailability and accumulation of mercury in aquatic organisms. For that reason, multivariate analyses on benthic invertebrate methylmercury concentrations and water chemistry from 12 Quebec water bodies were used to construct simple, predictive models of benthic invertebrate methylmercury in 23 lakes in Ontario and Quebec. The study showed that the primary means of mercury accumulation for organisms in higher trophic positions is dietary through the assimilation of organic forms of mercury, principally methylmercury. The data from 12 Quebec water bodies, revealed that benthic invertebrates in reservoirs have higher methylmercury than those in natural lakes, and methylmercury is generally higher in predatory invertebrates. Reservoir age was found to correlate with fish, benthic invertebrate methylmercury, and also with lake chemistry parameters such as pH and dissolved organic carbon (DOC). The objective of the study was to determine the appropriate level of taxonomic or functional resolution for generating benthic invertebrate methylmercury models, and to identify which environmental variables correlate most with benthic invertebrate methylmercury. Empirical models using these correlations were constructed and their predicted efficiency was tested by cross-validation. In addition, the effect of exposure to fish digestive enzymes on invertebrate methylmercury was

  5. Validation of a method to determine methylmercury in fish tissues using gas chromatography

    International Nuclear Information System (INIS)

    Vega Bolannos, Luisa O.; Arias Verdes, Jose A.; Beltran Llerandi, Gilberto; Castro Diaz, Odalys; Moreno Tellez, Olga L.

    2000-01-01

    We validated a method to determine methylmercury in fish tissues using gas chromatography with an electron capture detector as described by the Association of Official Analytical Chemist (AOAC) International. The linear curve range was 0.02 to 1 g/ml and linear correlation coefficient was 0.9979. A 1 mg/kg methylmercury-contaminated fish sample was analyzed 20 times to determine repeatability of the method. The quantification limit was 0.16 mg/kg and detection limit was 0.06 ppm. Fish samples contaminated with 0.2 to 10 mg/kg methylmercury showed recovery indexes from 94.66 to 108.8%

  6. Acute Effects of (Bis)tributyltin Oxide on Marine Organisms. Summary of Work Performed 1981 to 1983

    Science.gov (United States)

    1989-05-01

    concentrations of monobutyltin, dibutyltin, and tributyltin to determine the relative toxicity of these compounds. The concentrations tested were as follows...butyl groups, i.e., monobutyltin is less toxic than dibutyltin, wh; .J less toxic than tributyltin . It also demonstrated the need for field work to...chronic rSTcxposure on mussels have indicated a 66-day I-Cj,, near 1.0 ppb. These findings coincide with our earlier work in that TBT is highly toxic

  7. Elucidating the mechanism of action of tributyltin (TBT) in zebrafish.

    Science.gov (United States)

    McGinnis, Courtney L; Crivello, Joseph F

    2011-05-01

    Tributyltin (TBT), an antifouling agent, has been implicated in the masculinization of fish species worldwide, but the masculinizing mechanism is not fully understood. We have examined the actions of TBT as an endocrine disruptor in zebrafish (Danio rerio). In HeLa cells transiently co-transfected with plasmid constructs containing the zebrafish estrogen receptors (zfERα, zfERβ(1) and zfERβ(2)) and the zebrafish estrogen response element (zfERE-tk-luc), ethinyl estradiol (EE2) induced luciferase activity 4 to 6-fold and was inhibited by TBT. In HeLa cells transiently co-transfected with the zebrafish androgen receptor (zfAR) and the murine androgen receptor response element (ARE-slp-luc), testosterone induced luciferase activity was not inhibited by TBT. In HeLa cells co-transfected with zfERα, zfERβ(1) and zfERβ(2) and a plasmid containing zebrafish aromatase (zfCyp19b-luc), TBT inhibited luciferase activity. In zebrafish exposed to 1mg/kg and 5mg/kg TBT in vivo, there was a increase in liver sulfotransferase and a decrease acyl-CoA testosterone acyltransferase activity. Real-time PCR analysis of sexual differentiation markers in fish exposed to TBT in vivo revealed a tissue-specific response. In brain there was increased production of Sox9, Dax1, and SF1 mRNA, an androgenizing effect, while in the liver there was increased production of Dax1, Cyp19a and zfERβ(1) mRNA but decreased production of Sox9 mRNA, a feminizing effect. In the gonads there was increased production of zfERα and zfCyp19a mRNA, again a feminizing effect. TBT has an overall masculinizing effect but the masculinizing effect is tempered by a feminizing effect on gene transcription in certain tissues. These results are discussed in the context of TBT as an endocrine disruptor in zebrafish. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Environmental Impact of Tributyltin-Resistant Marine Bacteria in the Indigenous Microbial Population of Tributyltin-Polluted Surface Sediments.

    Science.gov (United States)

    Mimura, Haruo; Yagi, Masahiro; Yoshida, Kazutoshi

    2017-01-01

     We compared the TBT-resistant ability of resting cells prepared from isolates that formed colonies on nutrient agar plates containing 100 µM tributyltin (TBT) chloride, such as Photobacterium sp. TKY1, Halomonas sp. TKY2, and Photobacterium sp. NGY1, with those from taxonomically similar type strains. Photobacterium sp. TKY1 showed the highest ability among those three isolates. The number of surviving Photobacterium sp. TKY1 cells was hardly decreased after 1 h of exposure to 100 µM TBTCl, regardless of the number of resting cells in the range from 10 9.4 to 10 4.2 CFU mL -1 . In such an experimental condition, the maximum number of TBT molecules available to associate with a single cell was estimated to be approximately 6.0 x 10 11.8 . Resting cells prepared from type strains Photobacterium ganghwense JCM 12487 T and P. halotolerans LMG 22194 T , which have 16S rDNA sequences highly homologous with those of Photobacterium sp. TKY1, showed sensitivity to TBT, indicating that TBT-resistant marine bacterial species are not closely related in spite of their taxonomic similarity. We also estimated the impact of TBT-resistant bacterial species to indigenous microbial populations of TBT-polluted surface sediments. The number of surviving TBT-sensitive Vibrio natriegens ATCC 14048 T cells, 10 6.2±0.3 CFU mL -1 , was reduced to 10 4.4±0.4 CFU mL -1 when TBT-resistant Photobacterium sp. TKY1 cells, 10 9.1±0.2 CFU mL -1 , coexisted with 10 9.4±0.2 CFU mL -1 of V. natriegens ATCC 14048 T cells in the presence of 100 µM TBTCl. These results indicate that the toxicity of TBT to TBT-sensitive marine bacterial populations might be enhanced when a TBT-resistant marine bacterial species inhabits TBT-polluted surface sediments.

  9. Methylmercury in the Gulf of Mexico: State of Knowledge and Research Needs

    National Research Council Canada - National Science Library

    2004-01-01

    The Interagency Working Group on Methylmercury was formed in response to concern about potential adverse effects on human health associated with consumption of fish and shellfish in the Gulf of Mexico...

  10. The micro-scale synthesis of (117)Sn-enriched tributyltin chloride and its characterization by GC-ICP-MS and NMR techniques.

    Science.gov (United States)

    Peeters, Kelly; Iskra, Jernej; Zuliani, Tea; Ščančar, Janez; Milačič, Radmila

    2014-07-01

    Organotin compounds (OTCs) are among the most toxic substances ever introduced to the environment by man. They are common pollutants in marine ecosystems, but are also present in the terrestrial environment, accumulated mainly in sewage sludge and landfill leachates. In investigations of the degradation and methylation processes of OTC in environmental samples, the use of enriched isotopic tracers represents a powerful analytical tool. Sn-enriched OTC are also necessary in application of the isotope dilution mass spectrometry technique for their accurate quantification. Since Sn-enriched monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) are not commercially available as single species, "in house" synthesis of individual butyltin-enriched species is necessary. In the present work, the preparation of the most toxic butyltin, namely TBT, was performed via a simple synthetic path, starting with bromination of metallic Sn, followed by butylation with butyl lithium. The tetrabutyltin (TeBT) formed was transformed to tributyltin chloride (TBTCl) using concentrated hydrochloric acid (HCl). The purity of the synthesized TBT was verified by speciation analysis using the techniques of gas chromatography coupled to inductively coupled plasma mass spectrometry (GC-ICP-MS) and nuclear magnetic resonance (NMR). The results showed that TBT had a purity of more than 97%. The remaining 3% corresponded to DBT. TBT was quantified by reverse isotope dilution GC-ICP-MS. The synthesis yield was around 60%. The advantage of this procedure over those previously reported lies in its possibility to be applied on a micro-scale (starting with 10mg of metallic Sn). This feature is of crucial importance, since enriched metallic Sn is extremely expensive. The procedure is simple and repeatable, and was successfully applied for the preparation of (117)Sn-enriched TBTCl from (117)Sn-enriched metal. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Methylmercury in a predatory fish (Cichla spp.) inhabiting the Brazilian Amazon

    Energy Technology Data Exchange (ETDEWEB)

    Kehrig, Helena do A [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-902 Rio de Janeiro (Brazil)], E-mail: kehrig@biof.ufrj.br; Howard, Bruce M. [T.H. Huxley School, Imperial College, London SW7 2BP (United Kingdom); Malm, Olaf [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-902 Rio de Janeiro (Brazil)

    2008-07-15

    This research tested whether limnological conditions, biological characteristics of fish and anthropogenic impacts influenced the assimilation of methylmercury into the muscle of a sedentary piscivorous fish, Cichla spp., from three rivers (Negro, Madeira, Tapajos) and two hydroelectric reservoirs (Balbina, Tucurui) within the Brazilian Amazon. Methylmercury in this fish ranged from 0.04 to 1.43 {mu}g g{sup -1} w.w. across sites. No significant differences were observed in the methylmercury concentrations between males and females, or for different morphotypes of this species. Positive correlations were found between methylmercury and fish body weight. No differences were found between the weight normalized methylmercury (MeHg) concentrations or its percent of total mercury in fish from the three rivers; weight normalized MeHg was highest in one of the two reservoirs. In Rio Tapajos, where gold mining and deforestation cause high water turbidity, fish showed the highest MeHg and concentrations were different across the four sites examined. In all sampling areas, the %MeHg was found to be higher than 70. - Cichla spp. may be considered good bioindicators of methylmercury contamination in the Amazonian ecosystem because of their integration of this pollutant over time.

  12. Methylmercury inhibits prolactin release in a cell line of pituitary origin

    Directory of Open Access Journals (Sweden)

    L.A.L. Maués

    2015-08-01

    Full Text Available Heavy metals, such as methylmercury, are key environmental pollutants that easily reach human beings by bioaccumulation through the food chain. Several reports have demonstrated that endocrine organs, and especially the pituitary gland, are potential targets for mercury accumulation; however, the effects on the regulation of hormonal release are unclear. It has been suggested that serum prolactin could represent a biomarker of heavy metal exposure. The aim of this study was to evaluate the effect of methylmercury on prolactin release and the role of the nitrergic system using prolactin secretory cells (the mammosomatotroph cell line, GH3B6. Exposure to methylmercury (0-100 μM was cytotoxic in a time- and concentration-dependent manner, with an LC50 higher than described for cells of neuronal origin, suggesting GH3B6 cells have a relative resistance. Methylmercury (at exposures as low as 1 μM for 2 h also decreased prolactin release. Interestingly, inhibition of nitric oxide synthase by N-nitro-L-arginine completely prevented the decrease in prolactin release without acute neurotoxic effects of methylmercury. These data indicate that the decrease in prolactin production occurs via activation of the nitrergic system and is an early effect of methylmercury in cells of pituitary origin.

  13. Methylmercury in a predatory fish (Cichla spp.) inhabiting the Brazilian Amazon

    International Nuclear Information System (INIS)

    Kehrig, Helena do A; Howard, Bruce M.; Malm, Olaf

    2008-01-01

    This research tested whether limnological conditions, biological characteristics of fish and anthropogenic impacts influenced the assimilation of methylmercury into the muscle of a sedentary piscivorous fish, Cichla spp., from three rivers (Negro, Madeira, Tapajos) and two hydroelectric reservoirs (Balbina, Tucurui) within the Brazilian Amazon. Methylmercury in this fish ranged from 0.04 to 1.43 μg g -1 w.w. across sites. No significant differences were observed in the methylmercury concentrations between males and females, or for different morphotypes of this species. Positive correlations were found between methylmercury and fish body weight. No differences were found between the weight normalized methylmercury (MeHg) concentrations or its percent of total mercury in fish from the three rivers; weight normalized MeHg was highest in one of the two reservoirs. In Rio Tapajos, where gold mining and deforestation cause high water turbidity, fish showed the highest MeHg and concentrations were different across the four sites examined. In all sampling areas, the %MeHg was found to be higher than 70. - Cichla spp. may be considered good bioindicators of methylmercury contamination in the Amazonian ecosystem because of their integration of this pollutant over time

  14. Psychophysical sensory examination in individuals with a history of methylmercury exposure

    International Nuclear Information System (INIS)

    Takaoka, Shigeru; Fujino, Tadashi; Sekikawa, Tomoko; Miyaoka, Tetsu

    2004-01-01

    Paresthesias are the first symptom that people report following toxic doses of methylmercury. The authors conducted a psychophysical study of tactile sensation to evaluate the somatosensory abilities of subjects living in a methylmercury-polluted area around Minamata City, Japan. The authors examined control subjects and methylmercury-exposed subjects with and without numbness. A history of methylmercury exposure was taken and a neurological examination performed. Aluminum-oxide abrasive papers were used as stimuli in a psychophysical sensory examination of fine-surface-texture discrimination. Difference thresholds from 3 μm were calculated by the two-alternative, forced-choice technique. Difference thresholds in control subjects were also calculated for comparison. The difference threshold was 6.3 μm in exposed subjects with sensory symptoms, 4.9 μm in exposed subjects without sensory symptoms, and 2.7 μm in control subjects. Acuity of fine-surface-texture discrimination was disturbed not only in subjects with clinical complaints of hand numbness, but also in subjects without hand numbness who lived in the district where methylmercury exposure occurred. Sensory testing using a psychophysical test of fine-surface-texture discrimination in this population suggests that the number of individuals affected by methylmercury exposure in the polluted area was greater than previously reported

  15. Effects of tributyltin on metamorphosis and gonadal differentiation of Xenopus laevis at environmentally relevant concentrations.

    Science.gov (United States)

    Shi, Huahong; Zhu, Pan; Guo, Suzhen

    2014-05-01

    Tributyltin (TBT), a well known endocrine disruptor, has high teratogenicity to embryos of amphibian (Xenopus tropicalis). An amphibian metamorphosis assay (AMA) and a complete AMA (CAMA) were conducted for TBT. In AMA, the body weight, the snout-to-vent length and the hind limb length of X. laevis tadpoles were decreased in tributyltin chloride (TBTCl; 12.5-200 ng/L) treatment groups after 7 days exposure. TBT greatly retarded the development of tadpoles, decreased the number of follicle and induced thyroid follicle cell hyperplasia after 19 days exposure. In CAMA, 10 and 100 ng/L TBTCl led to various malformations of gonad, including intersex, segmental aplasia and multiple ovary cavities of X. laevis following exposure from stages 46 to stage 66. The sex ratio was male-biased in TBT treatment groups. These results suggest that TBT delayed the metamorphosis, inhibited the growth of tadpoles and disrupted the gonadal differentiation of X. laevis at environmentally relevant concentrations.

  16. Tributyltin (TBT) induces oxidative stress and modifies lipid profile in the filamentous fungus Cunninghamella elegans.

    Science.gov (United States)

    Bernat, Przemysław; Gajewska, Ewa; Szewczyk, Rafał; Słaba, Mirosława; Długoński, Jerzy

    2014-03-01

    To investigate the response of the tributyltin-degrading fungal strain Cunninghamella elegans to the organotin, a comparative lipidomics strategy was employed using an LC/MS-MS technique. A total of 49 lipid species were identified. Individual phospholipids were then quantified using a multiple reaction monitoring method. Tributyltin (TBT) caused a decline in the amounts of many molecular species of phosphatidylethanolamine or phosphatidylserine and an increase in the levels of phosphatidic acid, phosphatidylinositol and phosphatidylcholine. In the presence of TBT, it was observed that overall unsaturation was lower than in the control. Lipidome data were analyzed using principal component analysis, which confirmed the compositional changes in membrane lipids in response to TBT. Additionally, treatment of fungal biomass with butyltin led to a significant increase in lipid peroxidation. It is suggested that modification of the phospholipids profile and lipids peroxidation may reflect damage to mycelium caused by TBT.

  17. Behavioral effects of developmental methylmercury drinking water exposure in rodents.

    Science.gov (United States)

    Bisen-Hersh, Emily B; Farina, Marcelo; Barbosa, Fernando; Rocha, Joao B T; Aschner, Michael

    2014-04-01

    Early methylmercury (MeHg) exposure can have long-lasting consequences likely arising from impaired developmental processes, the outcome of which has been exposed in several longitudinal studies of affected populations. Given the large number of newborns at an increased risk of learning disabilities associated with in utero MeHg exposure, it is important to study neurobehavioral alterations using ecologically valid and physiologically relevant models. This review highlights the benefits of using the MeHg drinking water exposure paradigm and outlines behavioral outcomes arising from this procedure in rodents. Combination treatments that exacerbate or ameliorate MeHg-induced effects, and possible molecular mechanisms underlying behavioral impairment are also discussed. Copyright © 2013 Elsevier GmbH. All rights reserved.

  18. Methylmercury chloride induces learning deficits in prenatally treated rats

    Energy Technology Data Exchange (ETDEWEB)

    Muesch, H.R.; Bornhausen, M.; Kriegel, H.; Greim, H.

    1978-01-01

    Methylmercury chloride (MMC) was given to pregnant rats on the 6th, 7th, 8th, and 9th day after conception in doses of 0.05 and 2.0 mg/kg/day. The female offspring of these animals were tested 90 days after birth for learning ability using operant conditioning procedures. The rats were kept at 90% of their normal body weight and trained in a lever-box to press a bar in order to obtain a food pellet. Significant differences in the acquisition speed became apparent when the ratio of bar presses to reward was increased in a classical contingency of differential reinforcement of high rates even at MMC-doses of 4 x 0.05 mg/kg. These differences were not found in the general motility level nor in motor coordination.

  19. DOE/FDA/EPA: Workshop on methylmercury and human health

    Energy Technology Data Exchange (ETDEWEB)

    Moskowitz, P.D.; Saroff, L.; Bolger, M.; Cicmanec, J.; Durkee, S. [eds.

    1994-12-31

    In the US the general population is exposed to methylmercury (MeHg) principally through the consumption of fish. There is continuing discussion about the sources of this form of mercury (Hg), the magnitudes and trends in exposures to consumers, and the significance of the sources and their contributions to human health. In response to these discussions, the US Department of Energy, the US Food and Drug Administration, and the US Environmental Protection Agency cosponsored a two-day workshop to discuss data and methods available for characterizing the risk to human health presented by MeHg. This workshop was attended by 45 individuals representing various Federal and state organizations and interested stakeholders. The agenda covered: Agency interests; probabilistic approach to risk assessment; emission sources; atmospheric transport; biogeochemical cycling; exposure assessment; health effects of MeHg; and research needs.

  20. Assessing Sources of Human Methylmercury Exposure Using Stable Mercury Isotopes

    DEFF Research Database (Denmark)

    Li, Miling; Sherman, Laura S; Blum, Joel D

    2014-01-01

    Seafood consumption is the primary route of methylmercury (MeHg) exposure for most populations. Inherent uncertainties in dietary survey data point to the need for an empirical tool to confirm exposure sources. We therefore explore the utility of Hg stable isotope ratios in human hair as a new...... method for discerning MeHg exposure sources. We characterized Hg isotope fractionation between humans and their diets using hair samples from Faroese whalers exposed to MeHg predominantly from pilot whales. We observed an increase of 1.75‰ in δ(202)Hg values between pilot whale muscle tissue and Faroese...... whalers' hair but no mass-independent fractionation. We found a similar offset in δ(202)Hg between consumed seafood and hair samples from Gulf of Mexico recreational anglers who are exposed to lower levels of MeHg from a variety of seafood sources. An isotope mixing model was used to estimate individual...

  1. Mandelbrot's Extremism

    NARCIS (Netherlands)

    Beirlant, J.; Schoutens, W.; Segers, J.J.J.

    2004-01-01

    In the sixties Mandelbrot already showed that extreme price swings are more likely than some of us think or incorporate in our models.A modern toolbox for analyzing such rare events can be found in the field of extreme value theory.At the core of extreme value theory lies the modelling of maxima

  2. Biochar amendment reduced methylmercury accumulation in rice plants

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Rui; Wang, Yongjie [School of Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, People’s Republic of China (China); Zhong, Huan, E-mail: zhonghuan@nju.edu.cn [School of Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, People’s Republic of China (China); Environmental and Life Sciences Program (EnLS), Trent University, Peterborough, Ontario (Canada)

    2016-08-05

    Highlights: • Biochar amendment could evidently reduce methylmercury (MeHg) levels in rice grain. • Biochar could enhance microbial production of MeHg, probably by providing sulfate. • Biochar could immobilize MeHg in soil, and reduce MeHg availability to rice plants. • Biochar amendment increased grain biomass, leading to biodilution of MeHg in grain. - Abstract: There is growing concern about methylmercury (MeHg) accumulation in rice grains and thus enhanced dietary exposure to MeHg in Asian countries. Here, we explored the possibility of reducing grain MeHg levels by biochar amendment, and the underlying mechanisms. Pot (i.e., rice cultivation in biochar amended soils) and batch experiments (i.e., incubation of amended soils under laboratory conditions) were carried out, to investigate MeHg dynamics (i.e., MeHg production, partitioning and phytoavailability in paddy soils, and MeHg uptake by rice) under biochar amendment (1–4% of soil mass). We demonstrate for the first time that biochar amendment could evidently reduce grain MeHg levels (49–92%). The declines could be attributed to the combined effects of: (1) increased soil MeHg concentrations, probably explained by the release of sulfate from biochar and thus enhanced microbial production of MeHg (e.g., by sulfate-reducing bacteria), (2) MeHg immobilization in soils, facilitated by the large surface areas and high organosulfur content of biochar, and (3) biodilution of MeHg in rice grains, due to the increased grain biomass under biochar amendment (35–79%). These observations together with mechanistic explanations improve understanding of MeHg dynamics in soil-rice systems, and support the possibility of reducing MeHg phytoaccumulation under biochar amendment.

  3. Biochar amendment reduced methylmercury accumulation in rice plants

    International Nuclear Information System (INIS)

    Shu, Rui; Wang, Yongjie; Zhong, Huan

    2016-01-01

    Highlights: • Biochar amendment could evidently reduce methylmercury (MeHg) levels in rice grain. • Biochar could enhance microbial production of MeHg, probably by providing sulfate. • Biochar could immobilize MeHg in soil, and reduce MeHg availability to rice plants. • Biochar amendment increased grain biomass, leading to biodilution of MeHg in grain. - Abstract: There is growing concern about methylmercury (MeHg) accumulation in rice grains and thus enhanced dietary exposure to MeHg in Asian countries. Here, we explored the possibility of reducing grain MeHg levels by biochar amendment, and the underlying mechanisms. Pot (i.e., rice cultivation in biochar amended soils) and batch experiments (i.e., incubation of amended soils under laboratory conditions) were carried out, to investigate MeHg dynamics (i.e., MeHg production, partitioning and phytoavailability in paddy soils, and MeHg uptake by rice) under biochar amendment (1–4% of soil mass). We demonstrate for the first time that biochar amendment could evidently reduce grain MeHg levels (49–92%). The declines could be attributed to the combined effects of: (1) increased soil MeHg concentrations, probably explained by the release of sulfate from biochar and thus enhanced microbial production of MeHg (e.g., by sulfate-reducing bacteria), (2) MeHg immobilization in soils, facilitated by the large surface areas and high organosulfur content of biochar, and (3) biodilution of MeHg in rice grains, due to the increased grain biomass under biochar amendment (35–79%). These observations together with mechanistic explanations improve understanding of MeHg dynamics in soil-rice systems, and support the possibility of reducing MeHg phytoaccumulation under biochar amendment.

  4. Tributyltin-induced endoplasmic reticulum stress and its Ca2+-mediated mechanism

    International Nuclear Information System (INIS)

    Isomura, Midori; Kotake, Yaichiro; Masuda, Kyoichi; Miyara, Masatsugu; Okuda, Katsuhiro; Samizo, Shigeyoshi; Sanoh, Seigo; Hosoi, Toru; Ozawa, Koichiro; Ohta, Shigeru

    2013-01-01

    Organotin compounds, especially tributyltin chloride (TBT), have been widely used in antifouling paints for marine vessels, but exhibit various toxicities in mammals. The endoplasmic reticulum (ER) is a multifunctional organelle that controls post-translational modification and intracellular Ca 2+ signaling. When the capacity of the quality control system of ER is exceeded under stress including ER Ca 2+ homeostasis disruption, ER functions are impaired and unfolded proteins are accumulated in ER lumen, which is called ER stress. Here, we examined whether TBT causes ER stress in human neuroblastoma SH-SY5Y cells. We found that 700 nM TBT induced ER stress markers such as CHOP, GRP78, spliced XBP1 mRNA and phosphorylated eIF2α. TBT also decreased the cell viability both concentration- and time-dependently. Dibutyltin and monobutyltin did not induce ER stress markers. We hypothesized that TBT induces ER stress via Ca 2+ depletion, and to test this idea, we examined the effect of TBT on intracellular Ca 2+ concentration using fura-2 AM, a Ca 2+ fluorescent probe. TBT increased intracellular Ca 2+ concentration in a TBT-concentration-dependent manner, and Ca 2+ increase in 700 nM TBT was mainly blocked by 50 μM dantrolene, a ryanodine receptor antagonist (about 70% inhibition). Dantrolene also partially but significantly inhibited TBT-induced GRP78 expression and cell death. These results suggest that TBT increases intracellular Ca 2+ concentration by releasing Ca 2+ from ER, thereby causing ER stress. - Highlights: • We established that tributyltin induces endoplasmic reticulum (ER) stress. • Tributyltin induces ER stress markers in a concentration-dependent manner. • Tributyltin increases Ca 2+ release from ER, thereby causing ER stress. • Dibutyltin and monobutyltin did not increase GRP78 or intracellular Ca 2+

  5. Distribution of Tributyltin in Tissues of Mature Japanese Whiting, Sillago japonica and Their Eggs

    OpenAIRE

    Shimasaki, Yohei; Oshima, Yuji; Inoue, Yoshiyuki; Shibata, Hisashi; Nakayama, Kei; Inoue, Suguru; Imoto, Hisaya; Kang, Ik Joon; Honjo, Tsuneo

    2008-01-01

    Tributyltin (TBT) has continued to pollute the coastal areas therein following global regulation for its use as an anti-fouling agent. The tissue dynamics of TBT in fish have been extensively documented, but few studies on maternal transfer of TBT have been performed. Previously, we reported that TBT was maternally transferred from parent fish to eggs. The present study examined the distribution of TBT in the tissues and spawned eggs of Japanese whiting, Sillago japonica, after dietary exp...

  6. Distribution and Fate of Tributyltin in the United States Marine Environment

    Science.gov (United States)

    Tributyltin ( TBT ) has been measured in water in 12 of 15 harbors studied during U.S. Navy baseline surveys. The highest concentrations of TBT (some...no detectable (5 ng dm-3) TBT . TBT monitoring studies with increased detection limits (l ng dm-3) have documented a high degree of TBT variability...associated with tide, season and intermittent point source discharges. Although yacht harbors were shown to be the principal TBT source in most regions

  7. The ygaVP Genes of Escherichia coli Form a Tributyltin-Inducible Operon▿ †

    OpenAIRE

    Gueuné, Hervé; Durand, Marie-José; Thouand, Gérald; DuBow, Michael S.

    2008-01-01

    A tributyltin (TBT) luxAB transcriptional fusion in Escherichia coli revealed that a TBT-activated promoter is located upstream of two cotranscribed orphan genes, ygaV and ygaP. We demonstrate that transcription from the promoter upstream of ygaVP is constitutive in a ygaVP mutant, suggesting that YgaV is an autoregulated, TBT-inducible repressor.

  8. Mussels as Bioindicators: A Case Study of Tributyltin Effects in San Diego Bay.

    Science.gov (United States)

    As part of a Navy research program to evaluate the environmental effects of tributyltin ( TBT ) antifouling coatings and develop in-situ field...documented temporal and spatial variability in TBT and the effects of TBT on growth, bioaccumulation and survival that have not been previously...the mussel bioidicator for assessing TBT effects in San Diego Bay and establishes a significant refinement in the use of mussels as biological

  9. Adverse effects of tributyltin on reproduction of Japanese medaka, Oryzias latipes

    OpenAIRE

    NAKAYAMA, Kei; OSHIMA, Yuji

    2008-01-01

    Tributyltin (TBT) is a typical endocrine disruptor that can induce imposex in mollusks and interfere with the reproduction in bivalves and fish. Our group has been studied the toxic effects of TBT using Japanese medaka (Oryzias latipes) as a model organism, and evaluated the effects on reproduction and behavior of medaka exposed to TBT. A series of our studies has demonstrated that TBT suppresses mating behavior in male and depresses fertility. We also observed that TBT exposure causes abnorm...

  10. Acute and Chronic Effects of Tributyltin on the Mysid Acanthomysis sculpta (Crustacea, Mysidacea).

    Science.gov (United States)

    1986-05-01

    juveniles . . . 19 12. Summary of chronic values in pg/L TBT . . . 26 viii INTRODUCTION Tributyltin ( TBT ) is commonly used as an antifouling toxicant in...juveniles was determined at 0 42-jig L TBT . Reproductive effects were the most sensitive sublethal indicator of TBT toxicity . A chronic value of 0.14-pgL...SI[CUmITV CLAShIFICATION OF THIS PASU M DAI &W- A comparison of TBT toxicity was performed using a TBT solution leached from painted panels

  11. Chronic Exposure to Tributyltin Induces Brain Functional Damage in Juvenile Common Carp (Cyprinus carpio)

    OpenAIRE

    Li, Zhi-Hua; Li, Ping; Shi, Ze-Chao

    2015-01-01

    The aim of the present study was to investigate the effect of Tributyltin (TBT) on brain function and neurotoxicity of freshwater teleost. The effects of long-term exposure to TBT on antioxidant related indices (MDA, malondialdehyde; SOD, superoxide dismutase; CAT, catalase; GR, glutathione reductase; GPx, glutathione peroxidase), Na+-K+-ATPase and neurological parameters (AChE, acetylcholinesterase; MAO, monoamine oxidase; NO, nitric oxide) in the brain of common carp were evaluated. Fish we...

  12. Low-Concentration Tributyltin Decreases GluR2 Expression via Nuclear Respiratory Factor-1 Inhibition

    OpenAIRE

    Ishida, Keishi; Aoki, Kaori; Takishita, Tomoko; Miyara, Masatsugu; Sakamoto, Shuichiro; Sanoh, Seigo; Kimura, Tomoki; Kanda, Yasunari; Ohta, Shigeru; Kotake, Yaichiro

    2017-01-01

    Tributyltin (TBT), which has been widely used as an antifouling agent in paints, is a common environmental pollutant. Although the toxicity of high-dose TBT has been extensively reported, the effects of low concentrations of TBT are relatively less well studied. We have previously reported that low-concentration TBT decreases ?-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptor subunit 2 (GluR2) expression in cortical neurons and enhances neuronal vulnerability ...

  13. Reproductive impacts of tributyltin (TBT) and triphenyltin (TPT) in the hermaphroditic freshwater gastropod Lymnaea stagnalis

    OpenAIRE

    Giusti, Arnaud; Barsi, Alpar; Dugue, Mael; Collinet, Marc; Thome, Jean-Pierre; Joaquim-Justo, Celia; Roig, Benoit; Lagadic, Laurent; Ducrot, Virginie

    2013-01-01

    Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment, they have mainly been tested separately for their effects on snail reproduction. Because large discrepancies in experimental conditions occurred in these tests, the present study aimed at comparing the relative toxicity of TBT and TPT under similar laboratory conditions in the 0–600 ng Sn/L...

  14. Tributyltin-induced endoplasmic reticulum stress and its Ca{sup 2+}-mediated mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Isomura, Midori; Kotake, Yaichiro, E-mail: yaichiro@hiroshima-u.ac.jp; Masuda, Kyoichi; Miyara, Masatsugu; Okuda, Katsuhiro; Samizo, Shigeyoshi; Sanoh, Seigo; Hosoi, Toru; Ozawa, Koichiro; Ohta, Shigeru

    2013-10-01

    Organotin compounds, especially tributyltin chloride (TBT), have been widely used in antifouling paints for marine vessels, but exhibit various toxicities in mammals. The endoplasmic reticulum (ER) is a multifunctional organelle that controls post-translational modification and intracellular Ca{sup 2+} signaling. When the capacity of the quality control system of ER is exceeded under stress including ER Ca{sup 2+} homeostasis disruption, ER functions are impaired and unfolded proteins are accumulated in ER lumen, which is called ER stress. Here, we examined whether TBT causes ER stress in human neuroblastoma SH-SY5Y cells. We found that 700 nM TBT induced ER stress markers such as CHOP, GRP78, spliced XBP1 mRNA and phosphorylated eIF2α. TBT also decreased the cell viability both concentration- and time-dependently. Dibutyltin and monobutyltin did not induce ER stress markers. We hypothesized that TBT induces ER stress via Ca{sup 2+} depletion, and to test this idea, we examined the effect of TBT on intracellular Ca{sup 2+} concentration using fura-2 AM, a Ca{sup 2+} fluorescent probe. TBT increased intracellular Ca{sup 2+} concentration in a TBT-concentration-dependent manner, and Ca{sup 2+} increase in 700 nM TBT was mainly blocked by 50 μM dantrolene, a ryanodine receptor antagonist (about 70% inhibition). Dantrolene also partially but significantly inhibited TBT-induced GRP78 expression and cell death. These results suggest that TBT increases intracellular Ca{sup 2+} concentration by releasing Ca{sup 2+} from ER, thereby causing ER stress. - Highlights: • We established that tributyltin induces endoplasmic reticulum (ER) stress. • Tributyltin induces ER stress markers in a concentration-dependent manner. • Tributyltin increases Ca{sup 2+} release from ER, thereby causing ER stress. • Dibutyltin and monobutyltin did not increase GRP78 or intracellular Ca{sup 2+}.

  15. Changes in the metabolic elimination profile of testosterone following exposure of the crustacean Daphnia magna to tributyltin.

    Science.gov (United States)

    LeBlanc, G A; McLachlan, J B

    2000-03-01

    The biocide tributyltin has been found to cause the development of pseudohermaphroditic conditions in some neogastropod species. These abnormalities of the reproductive system have adversely affected the fecundity of some field populations of gastropods, resulting in local population declines. Current evidence suggests that tributyltin elicits these effects by interfering with the biotransformation of testosterone to other steroid derivatives, resulting in an elevation in endogenous testosterone or some of its bioactive derivatives. The purpose of the present study was to determine whether tributyltin altered testosterone metabolism in daphnids (Daphnia magna), a species commonly used in ecotoxicology testing. Exposure of daphnids to 1.2 microg (tin)/L caused a general increase in the rate of elimination of oxido-reduced, hydroxylated, and glucose-conjugated derivatives of testosterone. However, tributyltin exposure had no significant effect on the rate of elimination of the glucose-conjugated forms of the various oxido-reduced and hydroxylated derivatives of testosterone. As a result, the percentage of the oxido-reduced and hydroxylated metabolites of testosterone eliminated as glucose conjugates decreased with increasing tributyltin exposure levels. These results demonstrate that tributyltin causes alterations in testosterone metabolism in daphnids that would result in an increase in the production of oxido-reduced derivatives. These products are preferentially retained in the tissues of daphnids and are variously androgenic in vertebrates. The increased production of oxido-reduced derivatives of testosterone may be mechanically responsible for the masculinizing effects of tributyltin in some species and suggests that daphnids may be a suitable surrogate for evaluating the potential of chemicals to elicit this form of toxicity. Copyright 2000 Academic Press.

  16. Deposition of mercury in forests across a montane elevation gradient: Elevational and seasonal patterns in methylmercury inputs and production

    Science.gov (United States)

    Gerson, Jacqueline R.; Driscoll, Charles T.; Demers, Jason D.; Sauer, Amy K.; Blackwell, Bradley D.; Montesdeoca, Mario R.; Shanley, James B.; Ross, Donald S.

    2017-08-01

    Global mercury contamination largely results from direct primary atmospheric and secondary legacy emissions, which can be deposited to ecosystems, converted to methylmercury, and bioaccumulated along food chains. We examined organic horizon soil samples collected across an elevational gradient on Whiteface Mountain in the Adirondack region of New York State, USA to determine spatial patterns in methylmercury concentrations across a forested montane landscape. We found that soil methylmercury concentrations were highest in the midelevation coniferous zone (0.39 ± 0.07 ng/g) compared to the higher elevation alpine zone (0.28 ± 0.04 ng/g) and particularly the lower elevation deciduous zone (0.17 ± 0.02 ng/g), while the percent of total mercury as methylmercury in soils decreased with elevation. We also found a seasonal pattern in soil methylmercury concentrations, with peak methylmercury values occurring in July. Given elevational patterns in temperature and bioavailable total mercury (derived from mineralization of soil organic matter), soil methylmercury concentrations appear to be driven by soil processing of ionic Hg, as opposed to atmospheric deposition of methylmercury. These methylmercury results are consistent with spatial patterns of mercury concentrations in songbird species observed from other studies, suggesting that future declines in mercury emissions could be important for reducing exposure of mercury to montane avian species.

  17. Deposition of mercury in forests across a montane elevation gradient: Elevational and seasonal patterns in methylmercury inputs and production

    Science.gov (United States)

    Gerson, Jacqueline R.; Driscoll, Charles T.; Demers, Jason D.; Sauer, Amy K.; Blackwell, Bradley D.; Montesdeoca, Mario R.; Shanley, James B.; Ross, Donald S.

    2017-01-01

    Global mercury contamination largely results from direct primary atmospheric and secondary legacy emissions, which can be deposited to ecosystems, converted to methylmercury, and bioaccumulated along food chains. We examined organic horizon soil samples collected across an elevational gradient on Whiteface Mountain in the Adirondack region of New York State, USA to determine spatial patterns in methylmercury concentrations across a forested montane landscape. We found that soil methylmercury concentrations were highest in the midelevation coniferous zone (0.39 ± 0.07 ng/g) compared to the higher elevation alpine zone (0.28 ± 0.04 ng/g) and particularly the lower elevation deciduous zone (0.17 ± 0.02 ng/g), while the percent of total mercury as methylmercury in soils decreased with elevation. We also found a seasonal pattern in soil methylmercury concentrations, with peak methylmercury values occurring in July. Given elevational patterns in temperature and bioavailable total mercury (derived from mineralization of soil organic matter), soil methylmercury concentrations appear to be driven by soil processing of ionic Hg, as opposed to atmospheric deposition of methylmercury. These methylmercury results are consistent with spatial patterns of mercury concentrations in songbird species observed from other studies, suggesting that future declines in mercury emissions could be important for reducing exposure of mercury to montane avian species.

  18. Protective effects of organoselenium compounds against methylmercury-induced oxidative stress in mouse brain mitochondrial-enriched fractions

    Directory of Open Access Journals (Sweden)

    D.F. Meinerz

    2011-11-01

    Full Text Available We evaluated the potential neuroprotective effect of 1-100 µM of four organoselenium compounds: diphenyl diselenide, 3’3-ditri-fluoromethyldiphenyl diselenide, p-methoxy-diphenyl diselenide, and p-chloro-diphenyl diselenide, against methylmercury-induced mitochondrial dysfunction and oxidative stress in mitochondrial-enriched fractions from adult Swiss mouse brain. Methylmercury (10-100 µM significantly decreased mitochondrial activity, assessed by MTT reduction assay, in a dose-dependent manner, which occurred in parallel with increased glutathione oxidation, hydroperoxide formation (xylenol orange assay and lipid peroxidation end-products (thiobarbituric acid reactive substances, TBARS. The co-incubation with diphenyl diselenide (100 µM completely prevented the disruption of mitochondrial activity as well as the increase in TBARS levels caused by methylmercury. The compound 3’3-ditrifluoromethyldiphenyl diselenide provided a partial but significant protection against methylmercury-induced mitochondrial dysfunction (45.4 ± 5.8% inhibition of the methylmercury effect. Diphenyl diselenide showed a higher thiol peroxidase activity compared to the other three compounds. Catalase blocked methylmercury-induced TBARS, pointing to hydrogen peroxide as a vector during methylmercury toxicity in this model. This result also suggests that thiol peroxidase activity of organoselenium compounds accounts for their protective actions against methylmercury-induced oxidative stress. Our results show that diphenyl diselenide and potentially other organoselenium compounds may represent important molecules in the search for an improved therapy against the deleterious effects of methylmercury as well as other mercury compounds.

  19. Stability studies of endocrine disrupting tributyltin and triphenyltin compounds in an artificial sea water model.

    Science.gov (United States)

    Novotny, Ladislav; Sharaf, Leyla; Abdel-Hamid, Mohammed E; Brtko, Julius

    2018-01-01

    Triorganotins belong to toxic components present predominantly in antifouling paints for marine vessels. Tributyltin/triphenyltin at pico- or nanomolar concentrations in sea water are known to induce an irreversible sexual abnormality in females of over 190 marine species, an "imposex" phenomenon - the superimposition of male genitalia on a female. Moreover, trialkyltins and triaryltins function as potent nuclear retinoid X receptors (RXR) agonists. In mammals, triorganotin compounds induce immunosuppressive, metabolic, reproductive or developmental effects. Toxic effects of triorganotins warrant the need for monitoring of their long-lasting presence in the environment. This study brings novel data on the stability of two triorganotin compounds in artificial sea water model obtained by applying ultra-pressure liquid chromatography (UPLC) and gas chromatography-mass spectrometry (GC-MS) methods. Stability of tributyltin and triphenyltin chlorides was studied for 180 days and the degradation kinetic parameters were obtained. Tributyltin chloride was the less stable with the degradation kinetic parameters Kdeg = 0.00014 day-1 and t1/2 = 4950 days (13.6 years). Kdeg of the more stable triphenyltin chloride was determined to be Kdeg = 0.00006 day-1 with t1/2 = 11550 days (31.6 years). Since similar stability data of triorganotin compounds were not published previously, we report high stability for both tested compounds, which indicates a significant environmental problem when these substances enter sea water and later coastal sediments.

  20. A microcosm approach to evaluate the degradation of tributyltin (TBT) by Aeromonas molluscorum Av27 in estuarine sediments.

    Science.gov (United States)

    Cruz, Andreia; Henriques, Isabel; Sousa, Ana C A; Baptista, Inês; Almeida, Adelaide; Takahashi, Shin; Tanabe, Shinsuke; Correia, António; Suzuki, Satoru; Anselmo, Ana Maria; Mendo, Sónia

    2014-07-01

    Tributyltin (TBT) is a biocide extremely toxic to a wide range of organisms, which has been used for decades in antifouling paints. Despite its global ban in 2008, TBT is still a problem of great concern due to the high levels trapped in sediments. Aeromonas molluscorum Av27 is a TBT degrading bacterium that was isolated from an estuarine system. We investigated the ability and the role of this bacterium on TBT degradation in this estuarine system, using a microcosm approach in order to mimic environmental conditions. The experiment was established and followed for 150 days. Simultaneously, changes in the indigenous bacterial community structure were also investigated. The results revealed a maximum TBT degradation rate of 28% accompanied by the detection of the degradation products over time. Additionally, it was observed that TBT degradation was significantly enhanced by the presence of Av27. In addition a significantly higher TBT degradation occurred when the concentration of Av27 was higher. TBT degradation affected the bacterial community composition as revealed by the changes in the prevalence of Proteobacteria subdivisions, namely the increase of Deltaproteobacteria and the onset of Epsilonproteobacteria. However, the addition of Av27 strain did not affect the dominant phylotypes. Total bacterial number, bacterial biomass productivity, 16S rRNA gene and denaturing gradient gel electrophoresis (DGGE) analyses also indicated alterations on the bacterial community structure over time, with bacteria non-tolerant to pollutants increasing their representativeness, as, for instance, the increase of the number of Alphaproteobacteria clones from 6% in the beginning to 12% at the end of the experiment. The work herein presented confirms the potential of Av27 strain to be used in the decontamination of TBT-polluted environments. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. [Fish and seafood as a source of human exposure to methylmercury].

    Science.gov (United States)

    Mania, Monika; Wojciechowska-Mazurek, Maria; Starska, Krystyna; Rebeniak, Małgorzata; Postupolski, Jacek

    2012-01-01

    Fish and seafood are recommended diet constituents providing high quality protein, vitamins, minerals and omega-3 fatty acids, mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, these foodstuffs can also be the major source ofmethylmercury intake in humans. In general, more than 90% of the mercury in fish is found as methylmercury, but contents of methylmercury can vary considerably between species. Predatory species that are at the top of the food chain and live a long time, may accumulate higher levels of methylmercury. This paper contains information about sources of human exposure to organic compounds of mercury, toxicity, metabolism and transformation of mercury in the environment. Assessment of methylmercury by international risk assessment bodies such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and U.S. National Research Council (NRC) were presented. Climate changes and their influence on the mercury cycle in the environment especially mercury methylation and concentrations of methylmercury in marine species were also presented. Consumer advice prepared by European Commission and Member States as regards consumption of predatory fishes such as swordfish, tuna, shark, marlin and pike, taking into account the most vulnerable groups of population e.g. women planning pregnancy, pregnant or breastfeeding women and children were presented. Mercury and methylmercury contamination of fishes and seafood on the basis of the literature references as well as intake of mercury with fish and fish products in Poland and other European country were discussed. The role of selenium as a factor which counteracts methylmercury toxicity and protects against some neurological effects of methylmercury exposure in humans, as well as information on potential etiological factors connected with autism disorder were also described. Attention has also been drawn to increasing number of notifications to Rapid Alert System for Food and Feed

  2. Low-level maternal methylmercury exposure through rice ingestion and potential implications for offspring health

    Energy Technology Data Exchange (ETDEWEB)

    Rothenberg, Sarah E., E-mail: rothenberg.sarah@gmail.com [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China); Feng Xinbin, E-mail: fengxinbin@vip.skleg.cn [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China); Li Ping [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China)

    2011-04-15

    Fish consumption is considered the primary pathway for MeHg (MeHg) exposure; however, MeHg exposure also occurs through rice ingestion. Rice is grown in an aquatic environment and although documented MeHg concentrations in rice are lower compared to fish tissue, human exposures exceed international guidelines in some regions where rice is a staple food and rice MeHg levels are elevated. Studies concerning human health exposure to MeHg should also include populations where maternal MeHg exposure occurs through ingestion of rice. Rice does not contain long-chain polyunsaturated fatty acids, which are associated with confounding developmental outcomes in offspring. Rice is also a staple food for more than half the world's population; therefore, it is critical to investigate the potential health risks of maternal ingestion of rice to the developing fetus, the most susceptible population to the deleterious effects of MeHg. Data concerning MeHg in rice are reviewed and micronutrients in rice are discussed. - Research highlights: > Maternal methylmercury exposure through rice may be important. > Rice does not contain the same micronutrients as fish, but may contain methylmercury. > Effects to offspring from methylmercury without beneficial micronutrients are unknown. - Studies concerning maternal methylmercury exposure and cognitive outcomes for offspring should include populations where rice ingestion is the primary methylmercury exposure pathway.

  3. Low-level maternal methylmercury exposure through rice ingestion and potential implications for offspring health

    International Nuclear Information System (INIS)

    Rothenberg, Sarah E.; Feng Xinbin; Li Ping

    2011-01-01

    Fish consumption is considered the primary pathway for MeHg (MeHg) exposure; however, MeHg exposure also occurs through rice ingestion. Rice is grown in an aquatic environment and although documented MeHg concentrations in rice are lower compared to fish tissue, human exposures exceed international guidelines in some regions where rice is a staple food and rice MeHg levels are elevated. Studies concerning human health exposure to MeHg should also include populations where maternal MeHg exposure occurs through ingestion of rice. Rice does not contain long-chain polyunsaturated fatty acids, which are associated with confounding developmental outcomes in offspring. Rice is also a staple food for more than half the world's population; therefore, it is critical to investigate the potential health risks of maternal ingestion of rice to the developing fetus, the most susceptible population to the deleterious effects of MeHg. Data concerning MeHg in rice are reviewed and micronutrients in rice are discussed. - Research highlights: → Maternal methylmercury exposure through rice may be important. → Rice does not contain the same micronutrients as fish, but may contain methylmercury. → Effects to offspring from methylmercury without beneficial micronutrients are unknown. - Studies concerning maternal methylmercury exposure and cognitive outcomes for offspring should include populations where rice ingestion is the primary methylmercury exposure pathway.

  4. Disturbances of perinatal carbohydrate metabolism in rats exposed to methylmercury in utero

    Energy Technology Data Exchange (ETDEWEB)

    Snell, K; Ashby, S L; Barton, S J

    1977-12-01

    Pregnant rats were given a single subcutaneous injection of methylmercuric chloride (at 4 or 8 mg/kg) on the ninth day of gestation. Fetal (2 days prenatal), newborn and postnatal (6 days post partum) animals from the methylmercury-treated mothers were investigated with respect to parameters of carbohydrate metabolism. In the absence of any physical abnormalities, fetal rats exposed to methylmercury in utero showed diminished concentrations of plasma glucose and liver glycogen concentrations and a lower hepatic glucose-6-phosphatase activity compared to control animals. Newborn rats from the methylmercury-treated mothers showed an impairment in glycogen mobilization in the first hours of extra-uterine life which was accompanied by a severe and protracted hypoglycemic response. Postnatal rats exposed to methylmercury in utero exhibited higher liver glycogen concentration and decreased body weights compared to control rats. The results point to a derangement of perinatal carbohydrate metabolism in the offspring of pregnant rats exposed briefly to low doses of methylmercury during gestation (''metabolic teratogenesis''). The postnatal hypoglycemic episode in exposed rats may contribute to the pathogenesis of the neurological disturbances revealed by these animals in later life.

  5. Incidence of invasive macrophytes on methylmercury budget in temperate lakes: Central role of bacterial periphytic communities

    International Nuclear Information System (INIS)

    Gentès, Sophie; Monperrus, Mathilde; Legeay, Alexia; Maury-Brachet, Régine; Davail, Stephane; André, Jean-Marc; Guyoneaud, Rémy

    2013-01-01

    Several studies demonstrated high mercury (Hg) methylation and demethylation in the periphyton associated with floating roots in tropical ecosystems. The importance of aquatic plants on methylmercury production in three temperate ecosystems from south-western France was evaluated through Hg species concentrations, and Hg methylation/demethylation activities by using stable isotopic tracers ( 199 Hg(II), Me 201 Hg). Hg accumulation and high methylation and demethylation yields were detected in plant roots and periphyton, whereas results for sediment and water were low to insignificant. The presence of sulfate reducing prokaryotes was detected in all compartments (T-RFLP based on dsrAB amplified through nested PCR) and their main role in Hg methylation could be demonstrated. In turn, sulfate reduction inhibition did not affect demethylation activities. The estimation of net MeHg budgets in these ecosystems suggested that aquatic rhizosphere is the principal location for methylmercury production and may represent an important source for the contamination of the aquatic food chain. - Highlights: ► Both Hg methylation and demethylation occur in the periphyton of temperate ecosystems. ► Aquatic rhizosphere is the main compartment for net methylmercury production. ► Sulfate reducers are detected in all ecosystem compartments (water, sediment, periphyton). ► Sulfate reducers are responsible for methylmercury production in aquatic roots. - The incidence of periphytic microbial communities on net methylmercury production is highlighted in temperate aquatic ecosystems.

  6. Reservoir stratification affects methylmercury levels in river water, plankton, and fish downstream from Balbina hydroelectric dam, Amazonas, Brazil.

    Science.gov (United States)

    Kasper, Daniele; Forsberg, Bruce R; Amaral, João H F; Leitão, Rafael P; Py-Daniel, Sarah S; Bastos, Wanderley R; Malm, Olaf

    2014-01-21

    The river downstream from a dam can be more contaminated by mercury than the reservoir itself. However, it is not clear how far the contamination occurs downstream. We investigated the seasonal variation of methylmercury levels in the Balbina reservoir and how they correlated with the levels encountered downstream from the dam. Water, plankton, and fishes were collected upstream and at sites between 0.5 and 250 km downstream from the dam during four expeditions in 2011 and 2012. Variations in thermal stratification of the reservoir influenced the methylmercury levels in the reservoir and in the river downstream. Uniform depth distributions of methylmercury and oxygen encountered in the poorly stratified reservoir during the rainy season collections coincided with uniformly low methylmercury levels along the river downstream from the dam. During dry season collections, the reservoir was strongly stratified, and anoxic hypolimnion water with high methylmercury levels was exported downstream. Methylmercury levels declined gradually to 200 km downstream. In general, the methylmercury levels in plankton and fishes downstream from the dam were higher than those upstream. Higher methylmercury levels observed 200-250 km downstream from the dam during flooding season campaigns may reflect the greater inflow from tributaries and flooding of natural wetlands that occurred at this time.

  7. Effects of low dose treatment of tributyltin on the regulation of estrogen receptor functions in MCF-7 cells

    International Nuclear Information System (INIS)

    Sharan, Shruti; Nikhil, Kumar; Roy, Partha

    2013-01-01

    Endocrine disrupting chemicals are the natural/synthetic compounds which mimic or inhibit the actions of endogenous hormones. Organotin compounds, such as tributyltin (TBT) are typical environmental contaminants and suspected endocrine-disrupting chemical. The present study evaluates the estrogenic potential of this compound in vitro in ER (+) breast adenocarcinoma, MCF-7 cell line. Our data showed that tributyltin chloride (TBTCl) had agonistic activities for estrogen receptor-α (ER-α). Its estrogenic potential was checked using cell proliferation assay, aromatase assay, transactivation assay, and protein expression analysis. Low dose treatment of TBTCl had a proliferative effect on MCF-7 cells and resulted in up-regulation of aromatase enzyme activity and enhanced estradiol production in MCF-7 cells. Immunofluorescence staining showed translocation of ER-α from cytoplasm to nucleus and increased expression of ER-α, 3β-HSD and aromatase on treatment with increasing doses of TBTCl. Further, to decipher the probable signaling pathways involved in its action, the MCF-7 cells were transfected with different pathway dependent luciferase reporter plasmids (CRE, SRE, NF-κB and AP1). A significant increase in CRE and SRE and decrease in NF-κB regulated pathway were observed (p < 0.05). Our results thus showed that the activation of SRE by TBTCl may be due to ligand dependent ER-α activation of the MAPK pathway and increased phosphorylation of ERK. In summary, the present data suggests that low dose of tributyltin genomically and non-genomically augmented estrogen dependent signaling by targeting various pathways. - Highlights: • Tributyltin chloride is agonistic to ER-α in MCF-7 cell line at low doses. • Tributyltin chloride up regulated aromatase activity and estradiol production. • Tributyltin chloride also activates MAPK pathway inducing ERK activation

  8. Effects of low dose treatment of tributyltin on the regulation of estrogen receptor functions in MCF-7 cells

    Energy Technology Data Exchange (ETDEWEB)

    Sharan, Shruti; Nikhil, Kumar; Roy, Partha, E-mail: paroyfbs@iitr.ernet.in

    2013-06-01

    Endocrine disrupting chemicals are the natural/synthetic compounds which mimic or inhibit the actions of endogenous hormones. Organotin compounds, such as tributyltin (TBT) are typical environmental contaminants and suspected endocrine-disrupting chemical. The present study evaluates the estrogenic potential of this compound in vitro in ER (+) breast adenocarcinoma, MCF-7 cell line. Our data showed that tributyltin chloride (TBTCl) had agonistic activities for estrogen receptor-α (ER-α). Its estrogenic potential was checked using cell proliferation assay, aromatase assay, transactivation assay, and protein expression analysis. Low dose treatment of TBTCl had a proliferative effect on MCF-7 cells and resulted in up-regulation of aromatase enzyme activity and enhanced estradiol production in MCF-7 cells. Immunofluorescence staining showed translocation of ER-α from cytoplasm to nucleus and increased expression of ER-α, 3β-HSD and aromatase on treatment with increasing doses of TBTCl. Further, to decipher the probable signaling pathways involved in its action, the MCF-7 cells were transfected with different pathway dependent luciferase reporter plasmids (CRE, SRE, NF-κB and AP1). A significant increase in CRE and SRE and decrease in NF-κB regulated pathway were observed (p < 0.05). Our results thus showed that the activation of SRE by TBTCl may be due to ligand dependent ER-α activation of the MAPK pathway and increased phosphorylation of ERK. In summary, the present data suggests that low dose of tributyltin genomically and non-genomically augmented estrogen dependent signaling by targeting various pathways. - Highlights: • Tributyltin chloride is agonistic to ER-α in MCF-7 cell line at low doses. • Tributyltin chloride up regulated aromatase activity and estradiol production. • Tributyltin chloride also activates MAPK pathway inducing ERK activation.

  9. Tetrodotoxin- and tributyltin-binding abilities of recombinant pufferfish saxitoxin and tetrodotoxin binding proteins of Takifugu rubripes.

    Science.gov (United States)

    Satone, Hina; Nonaka, Shohei; Lee, Jae Man; Shimasaki, Yohei; Kusakabe, Takahiro; Kawabata, Shun-Ichiro; Oshima, Yuji

    2017-01-01

    We investigated the ability of recombinant pufferfish saxitoxin and tetrodotoxin binding protein types 1 and 2 of Takifugu rubripes (rTrub.PSTBP1 and rTrub.PSTBP2) to bind to tetrodotoxin (TTX) and tributyltin. Both rTrub.PSTBPs bound to tributyltin in an ultrafiltration binding assay but lost this ability on heat denaturation. In contrast, only rTrub.PSTBP2 bound to TTX even heat denaturation. This result suggests that the amino acid sequence of PSTBP2 may be contributed for its affinity for TTX. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Chronic methylmercury exposure in the monkey (Macaca mulatta)

    Energy Technology Data Exchange (ETDEWEB)

    Luschei, E.; Mottet, N.K.; Shaw, C.M.

    1977-01-01

    Small daily doses of methylmercury hydroxide were administered to rhesus monkeys for periods of up to 17 months. Behavioral tests of peripheral vision and of the accuracy and rapidity of hand movements did not disclose any early subtle deficits preceding the onset of obvious signs of neurotoxicity. These signs appeared suddenly and involved reduced food intake (anorexia), clumsiness of jumping, loss of fine control of the digits, and uncoordinated mastication. With a constant daily dose of 0.1 mg/kg or less, blood concentration of mercury reached a peak after about 2 months, and then decreased to about half the peak value. Subsequently, increasing the daily dose level above 0.1 mg/kg (range of 0.12 to 0.21 mg/kg) produced an increase of blood concentration which tended to stabilize in the range of 2.0 to 2.5 ppM. After several months at these elevated concentrations all animals exhibited signs of neurotoxicity.

  11. Seasonality of dipteran-mediated methylmercury flux from ponds.

    Science.gov (United States)

    Chumchal, Matthew M; Drenner, Ray W; Hall, MacGregor N; Polk, D Kirkland; Williams, Edward B; Ortega-Rodriguez, Celeste L; Kennedy, James H

    2018-03-12

    Methylmercury (MeHg) is an aquatic contaminant that can be transferred to terrestrial predators by emergent aquatic insects. We assessed the effects of month and pond permanence on dipteran-mediated MeHg flux (calculated as emergent dipteran biomass × dipteran MeHg concentration) in 10 experimental ponds. Emergent dipterans were collected weekly from permanent ponds with bluegill (Lepomis macrochirus; n = 5) and semipermanent ponds without fish (n = 5) over a 7-mo period (February-August, 2015). We detected a significant effect of month on MeHg flux from 6 dipteran taxa and aggregate MeHg flux, with the highest MeHg flux from herbivorous/detritivorous chironomid midges and predatory midges in March; biting midges, phantom midges and herbivorous/detritivorous orthoclad midges in April; and mosquitoes in August. Aggregate dipteran-mediated MeHg flux peaked in April and then declined throughout the remainder of the summer. We did not detect a significant main effect of pond permanence or a significant month × pond permanence interaction effect on MeHg flux for any of the taxa examined in the present study or for aggregate MeHg flux. Given their ubiquity in aquatic systems and their importance in food webs at the land-water interface, dipterans are important taxa that should not be overlooked as a part of the Hg cycle. Environ Toxicol Chem 2018;9999:1-6. © 2018 SETAC. © 2018 SETAC.

  12. Biochar amendment reduced methylmercury accumulation in rice plants.

    Science.gov (United States)

    Shu, Rui; Wang, Yongjie; Zhong, Huan

    2016-08-05

    There is growing concern about methylmercury (MeHg) accumulation in rice grains and thus enhanced dietary exposure to MeHg in Asian countries. Here, we explored the possibility of reducing grain MeHg levels by biochar amendment, and the underlying mechanisms. Pot (i.e., rice cultivation in biochar amended soils) and batch experiments (i.e., incubation of amended soils under laboratory conditions) were carried out, to investigate MeHg dynamics (i.e., MeHg production, partitioning and phytoavailability in paddy soils, and MeHg uptake by rice) under biochar amendment (1-4% of soil mass). We demonstrate for the first time that biochar amendment could evidently reduce grain MeHg levels (49-92%). The declines could be attributed to the combined effects of: (1) increased soil MeHg concentrations, probably explained by the release of sulfate from biochar and thus enhanced microbial production of MeHg (e.g., by sulfate-reducing bacteria), (2) MeHg immobilization in soils, facilitated by the large surface areas and high organosulfur content of biochar, and (3) biodilution of MeHg in rice grains, due to the increased grain biomass under biochar amendment (35-79%). These observations together with mechanistic explanations improve understanding of MeHg dynamics in soil-rice systems, and support the possibility of reducing MeHg phytoaccumulation under biochar amendment. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Methylmercury biomagnification in an Arctic pelagic food web.

    Science.gov (United States)

    Ruus, Anders; Øverjordet, Ida B; Braaten, Hans Fredrik V; Evenset, Anita; Christensen, Guttorm; Heimstad, Eldbjørg S; Gabrielsen, Geir W; Borgå, Katrine

    2015-11-01

    Mercury (Hg) is a toxic element that enters the biosphere from natural and anthropogenic sources, and emitted gaseous Hg enters the Arctic from lower latitudes by long-range transport. In aquatic systems, anoxic conditions favor the bacterial transformation of inorganic Hg to methylmercury (MeHg), which has a greater potential for bioaccumulation than inorganic Hg and is the most toxic form of Hg. The main objective of the present study was to quantify the biomagnification of MeHg in a marine pelagic food web, comprising species of zooplankton, fish, and seabirds, from the Kongsfjorden system (Svalbard, Norway), by use of trophic magnification factors. As expected, tissue concentrations of MeHg increased with increasing trophic level in the food web, though at greater rates than observed in several earlier studies, especially at lower latitudes. There was strong correlation between MeHg and total Hg concentrations through the food web as a whole. The concentration of MeHg in kittiwake decreased from May to October, contributing to seasonal differences in trophic magnification factors. The ecology and physiology of the species comprising the food web in question may have a large influence on the magnitude of the biomagnification. A significant linear relationship was also observed between concentrations of selenium and total Hg in birds but not in zooplankton, suggesting the importance of selenium in Hg detoxification for individuals with high Hg concentrations. © 2015 SETAC.

  14. Extreme cosmos

    CERN Document Server

    Gaensler, Bryan

    2011-01-01

    The universe is all about extremes. Space has a temperature 270°C below freezing. Stars die in catastrophic supernova explosions a billion times brighter than the Sun. A black hole can generate 10 million trillion volts of electricity. And hypergiants are stars 2 billion kilometres across, larger than the orbit of Jupiter. Extreme Cosmos provides a stunning new view of the way the Universe works, seen through the lens of extremes: the fastest, hottest, heaviest, brightest, oldest, densest and even the loudest. This is an astronomy book that not only offers amazing facts and figures but also re

  15. Methylmercury Exposure and Incident Diabetes in U.S. Men and Women in Two Prospective Cohorts

    DEFF Research Database (Denmark)

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

    2013-01-01

    compared, and in analyses stratified by fish or omega-3 consumption, BMI, and age.CONCLUSIONSThese findings from two separate large prospective cohorts do not support adverse effects of methylmercury on development of diabetes in men or women at usual levels of exposure seen in these populations.......OBJECTIVEEmerging in vitro and animal evidence suggests that methylmercury could increase type 2 diabetes, but little evidence exists in humans. We aimed to prospectively determine associations of mercury exposure, as assessed by biomarker measurement, with incident diabetes.RESEARCH DESIGN...... AND METHODSWe used neutron activation analysis to measure toenail mercury, an objective biomarker of methylmercury exposure, in 9,267 adults free of diabetes at baseline in two separate U.S. prospective cohorts. Incident diabetes was identified from biennial questionnaires and confirmed by validated...

  16. Evaluation of diatomea algae Thalassiosira weissflogii sensitivity to chloride mercury and methylmercury by chlorophyll fluorescence analysis

    Science.gov (United States)

    Graevskaya, E. E.; Antal, T. K.; Matorin, D. N.; Voronova, E. N.; Pogosyan, S. I.; Rubin, A. B.

    2003-05-01

    Measurement of chlorophyll fluorescence has been shown to be a rapid, non-invasive, and reliable method to assess photosynthetic performance in a changing environment. In our study, the pulseamplitude-modulation (PAM) - fluorometric method was used to evaluate the sensitivity to chloride mercury and methylmercury chloride of diatomea microalgae Thalassiosira weissflogii. We found that 10^{-6} and 10^{-7} M MeHg led to a slow decrease in the PS II activity following for prolonged lag phase, whereas the algae was not sensitive to the same concentrations of HgCl2. However observed PS II inactivation by methylmercury was not complete and about 10 percents ofthe cells kept the high level of PS II activity as it was shown by microfluorometric analysis. These cells could determine adaptation of algae to methylmercury effect. Both toxicants decreased the rate of PS II reparation, as well as increased a heat pathway of excitation dissipation in PS II antennae complex.

  17. Placental and Fetal Disposition of Mercuric Ions in Rats Exposed to Methylmercury: Role of Mrp2

    Science.gov (United States)

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

    2012-01-01

    Methylmercury is a prevalent environmental toxicant that can have deleterious effects on a developing fetus. Previous studies indicate that the multidrug resistance-associated protein 2 (Mrp2) is involved in renal and hepatic export of mercuric ions. Therefore, we hypothesize that Mrp2 is also involved in export of mercuric ions from placental trophoblasts and fetal tissues. To test this hypothesis, we assessed the disposition of mercuric ions in pregnant Wistar and TR– (Mrp2-deficient) rats exposed to a single dose of methylmercury. The amount of mercury in renal tissues (cortex and outer stripe of outer medulla), liver, blood, amniotic fluid, uterus, placentas and fetuses was significantly greater in TR– rats than in Wistar rats. Urinary and fecal elimination of mercury was greater in Wistar dams than in TR– dams. Thus, our findings suggest that Mrp2 may be involved in the export of mercuric ions from maternal and fetal organs following exposure to methylmercury. PMID:23059061

  18. 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.

  19. Biosynthesis of methylmercury compounds by the intestinal flora of the rat

    International Nuclear Information System (INIS)

    Rowland, I.; Davies, M.; Grasso, P.

    1977-01-01

    The contents of the rat cecum and, to a lesser extent, those of the small intestine, synthesized methylmercury from mercuric chloride labeled with Hg 203 in vitro under aerobic or anaerobic conditions. The rate of formation was approximately 18 ng/g cecal contents/20 hr. The synthesis of methylmercury was inhibited by antibiotics and by filtration of the cecal contents through membrane filters, indicating that the bacterial flora of the gut participates in the reaction. Pure cultures of bacteria, isolated from the intestinal tract of the rat, could methylate mercuric chloride. It was estimated that the total amount of methylmercury synthesized from ingested inorganic mercury in man is approximately 400 ng/day

  20. Sweat gland toxicity induced by bis (tributyltin) oxide: an ultrastructural and X-ray microanalysis study

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, O. [Univ. of Occupational and Environmental Health Japan, Kitakyushu (Japan). Dept. of Dermatology and Occupational Dermatopathology; Doi, Y.; Kudo, H.; Fujimoto, S. [Univ. of Occupational and Environmental Health Japan, Kitakyushu (Japan). Dept. of Anatomy; Yoshizuka, M. [Kurume Univ. (Japan). Dept. of Anatomy

    2000-12-01

    Acute toxicity of bis (tributyltin) oxide in the sweat glands in the rat footpad was investigated by electron microscopy and an energy-dispersive X-ray microanalyzer. Male Wistar rats received an intramuscular injection of 0.5 ml/kg bis (tributyltin) oxide. After 6-8 h, swelling of mitochondria appeared in the secretory cells of the sweat glands. After 12 h, the secretory cells began to show intracytoplasmic edema. After 16-20 h, secretory cells in some sweat glands showed marked hydropic degeneration with swollen cytoplasm. Using X-ray microanalysis, tin peaks were preferentially obtained from the swollen mitochondria of the affected secretory cells. Mitochondria dysfunction due to the toxic effects of bis (tributyltin) oxide induced changes in the secretory cells of rat sweat glands contained three types of cells: degenerating dark cells, regenerating cells carrying injured mitochondria, and light cells which were morphologically very similar to the cells in the transitional portion of the sweat gland. These light cells appeared to differentiate into active secretory cells after settling down in the secretory portion. Based on these observations, we concluded that the cells in the transitional portion could play an important role at least as reserve cells against secretory cell toxicity. In association with the regenerating process of the damaged secretory portions, increased mitotic activities were seen in different areas of all the dermal sweat ducts. The above-mentioned morphological observations for cell damage and subsequent regeneration and renewal of secretory cells in sweat gland intoxication have not been reported so far. (orig.)

  1. Long term neurocognitive impact of low dose prenatal methylmercury exposure in Hong Kong.

    Science.gov (United States)

    Lam, Hugh Simon; Kwok, Ka Ming; Chan, Peggy Hiu Ying; So, Hung Kwan; Li, Albert Martin; Ng, Pak Cheung; Fok, Tai Fai

    2013-04-01

    International studies suggest that low dose prenatal methylmercury exposure (>29 nmol/L) has long-term adverse neurocognitive effects. There is evidence that the majority of children in Hong Kong exceed this level as a result of high fish consumption of mothers during pregnancy. To study whether there are any associations between low-dose prenatal methylmercury exposure and neurocognitive outcomes in Hong Kong children. All 1057 children from the original birth cohort were eligible for entry into the study, except children with conditions that would affect neurocognitive development, but were unrelated to methylmercury exposure. Subjects were assessed by a wide panel of tests covering a broad range of neurocognitive functions: Hong Kong Wechsler Intelligence Scale for Children (HK-WISC), Hong Kong List Learning Test (HKLLT), Tests of Everyday Attention for Children (TEACH), Boston Naming Test, and Grooved Pegboard Test. 608 subjects were recruited (median age 8.2 years, IQR 7.3, 8.8; 53.9% boys). After correction by confounders including child age and sex, multivariate analysis showed that cord blood mercury concentration was significantly associated with three subtests: Picture Arrangement of HK-WISC (coefficient -0.944, P=0.049) and Short and Long Delay Recall Difference of the HKLLT (coefficient -1.087, P=0.007 and coefficient -1.161, P=0.005, respectively), i.e., performance worsened with increasing prenatal methylmercury exposure in these subtests. Small, but statistically significant adverse associations between prenatal methylmercury exposure and long-term neurocognitive effects (a visual sequencing task and retention ability of verbal memory) were found in our study. These effects are compatible with findings of studies with higher prenatal methylmercury exposure levels and suggest that safe strategies to further reduce exposure levels in Hong Kong are desirable. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Toxicity of methylmercury injected into eggs when dissolved in water versus corn oil

    Science.gov (United States)

    Heinz, G.H.; Hoffman, D.J.; Klimstra, J.D.; Stebbins, K.R.; Kondrad, S.L.

    2011-01-01

    In a previous study, the embryotoxicity of methylmercury dissolved in corn oil was compared among 26 species of birds. Corn oil is not soluble in the water-based matrix that constitutes the albumen of an egg. To determine whether the use of corn oil limited the usefulness of this earlier study, a comparison was made of the embryotoxicity of methylmercury dissolved in corn oil versus water. Mallard (Anas platyrhynchos) and chicken (Gallus gallus) eggs were injected with methylmercury chloride dissolved in corn oil or water to achieve concentrations of 0, 0.2, 0.4, 0.8, and 1.6??g/g mercury in the egg on a wet weight basis. Hatching success at each dose of mercury was compared between the two solvents. For mallards, 16.4% of the eggs injected with 1.6??g/g mercury dissolved in water hatched, which was statistically lower than the 37.6% hatch rate of eggs injected with 1.6??g/g mercury dissolved in corn oil, but no differences in hatching success were observed between corn oil and water at any of the other doses. With chicken eggs, no significant differences occurred in percentage hatch of eggs between corn oil and water at any of the mercury doses. Methylmercury dissolved in corn oil seems to have a toxicity to avian embryos similar to that of does methylmercury dissolved in water. Consequently, the results from the earlier study that described the toxicity of methylmercury dissolved in corn oil to avian embryos were probably not compromised by the use of corn oil as a solvent. ?? 2011 SETAC.

  3. Serum/plasma methylmercury determination by isotope dilution gas chromatography-inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Douglas C., E-mail: douglas.baxter@alsglobal.com [ALS Scandinavia AB, Aurorum 10, 977 75 Lulea (Sweden); Faarinen, Mikko [ALS Scandinavia AB, Aurorum 10, 977 75 Lulea (Sweden); Osterlund, Helene; Rodushkin, Ilia [ALS Scandinavia AB, Aurorum 10, 977 75 Lulea (Sweden); Division of Geosciences, Lulea University of Technology, 977 87 Lulea (Sweden); Christensen, Morten [ALS Scandinavia AB, Maskinvaegen 2, 183 53 Taeby (Sweden)

    2011-09-09

    Highlights: {center_dot} We determine methylmercury in serum and plasma using isotope dilution calibration. {center_dot} Separation by gas chromatography and detection by inductively coupled plasma mass spectrometry. {center_dot} Data for 50 specimens provides first reference range for methylmercury in serum. {center_dot} Serum samples shown to be stable for 11 months in refrigerator. - Abstract: A method for the determination of methylmercury in plasma and serum samples was developed. The method uses isotope dilution with {sup 198}Hg-labeled methylmercury, extraction into dichloromethane, back-extraction into water, aqueous-phase ethylation, purge and trap collection, thermal desorption, separation by gas chromatography, and mercury isotope specific detection by inductively coupled plasma mass spectrometry. By spiking 2 mL sample with 1.2 ng tracer, measurements in a concentration interval of (0.007-2.9) {mu}g L{sup -1} could be performed with uncertainty amplification factors <2. A limit of quantification of 0.03 {mu}g L{sup -1} was estimated at 10 times the standard deviation of concentrations measured in preparation blanks. Within- and between-run relative standard deviations were <10% at added concentration levels of 0.14 {mu}g L{sup -1}, 0.35 {mu}g L{sup -1} and 2.8 {mu}g L{sup -1}, with recoveries in the range 82-110%. Application of the method to 50 plasma/serum samples yielded a median (mean; range) concentration of methylmercury of 0.081 (0.091; <0.03-0.19) {mu}g L{sup -1}. This is the first time methylmercury has been directly measured in this kind of specimen, and is therefore the first estimate of a reference range.

  4. Extraction of tributyltin and triphenyltin across a single oil droplet/water interface

    International Nuclear Information System (INIS)

    Chikama, Katsumi; Negishi, Takayuki; Nakatani, Kiyoharu

    2004-01-01

    Tributyltin (TBT + ) and triphenyltin (TPT + ) were extracted with merocyanine 540 (MC - ) from water into a 1,6-dichlorohexane droplet with the radius of 40 μm and the absorption spectra of MC - were measured by a single microdroplet manipulation and microabsorption technique. The mass transfer rate and the partitioning ratio of MC - were characteristically influenced by the TBT + , TPT + , MC - , and Cl - concentrations in water. The ion pair extraction processes of the organotin compounds with the anions were discussed in terms of the ion transfer and adsorption-desorption of the solutes

  5. Extraction of tributyltin and triphenyltin across a single oil droplet/water interface

    Energy Technology Data Exchange (ETDEWEB)

    Chikama, Katsumi; Negishi, Takayuki; Nakatani, Kiyoharu

    2004-07-01

    Tributyltin (TBT{sup +}) and triphenyltin (TPT{sup +}) were extracted with merocyanine 540 (MC{sup -}) from water into a 1,6-dichlorohexane droplet with the radius of 40 {mu}m and the absorption spectra of MC{sup -} were measured by a single microdroplet manipulation and microabsorption technique. The mass transfer rate and the partitioning ratio of MC{sup -} were characteristically influenced by the TBT{sup +}, TPT{sup +}, MC{sup -}, and Cl{sup -} concentrations in water. The ion pair extraction processes of the organotin compounds with the anions were discussed in terms of the ion transfer and adsorption-desorption of the solutes.

  6. Bioaccumulation of tributyltin and triphenyltin compounds through the food web in deep offshore water

    OpenAIRE

    KONO, Kumiko; MINAMI, Takashi; YAMADA, Hisashi; TANAKA, Hiroyuki; KOYAMA, Jiro

    2008-01-01

    Concentrations of tributyltin (TBT) and triphenyltin (TPT) compounds were determined in bottom seawater, sediments, and organisms of various trophic levels in the marine benthic food web in the Sea of Japan to clarify how the bioaccumulation patterns of TBT and TPT in the deep-sea ecosystem differ. TBT was detected in all samples: 0.3-0.8 ng/l in bottom seawater, 4.4-16 ng/g dry wt in sediment, and 1.8-240 ng/g dry wt in various organisms. TBT and TPT concentrations were lower in bottom seawa...

  7. Occurrence of Methylmercury in Rice-Based Infant Cereals and Estimation of Daily Dietary Intake of Methylmercury for Infants.

    Science.gov (United States)

    Cui, Wenbin; Liu, Guangliang; Bezerra, Mayara; Lagos, Danielle A; Li, Yanbin; Cai, Yong

    2017-11-08

    Recent reports of elevated levels of methylmercury (MeHg) in rice revealed the possible occurrence of MeHg in infant rice cereals, leading to potential MeHg exposure through cereal consumption. Total mercury (THg) and MeHg levels in 119 infant cereal samples commonly marketed in the United States and China and estimated daily intake of MeHg through cereal consumption were determined. Concentrations of THg and MeHg in the tested cereal samples ranged from 0.35 to 15.9 μg/kg and from 0.07 to 13.9 μg/kg with means of 2.86 and 1.61 μg/kg, respectively. Rice-based cereals contained MeHg levels significantly higher than those of nonrice cereals, indicating that MeHg in rice could be source of MeHg in cereals. Cereal consumption could be a potential pathway of MeHg exposure for infants, as the EDI through cereal consumption amounted to 4-122% of the MeHg reference dose, suggesting the necessity of further evaluation of the potential health risk of dietary MeHg exposure to infants.

  8. Determination of mercury and methylmercury in fishes of the Danube caught 1977 in Upper Austria

    International Nuclear Information System (INIS)

    Teherani, D.K.; Stehlik, G.; Tehrani, N.; Hinteregger, J.

    1977-09-01

    In 22 fishes from the Upper Austria part of the Danube mercury was determined by means of atomic absorption spectroscopy after a chemical pretreatment. 6 fishes from these also were proved in regard to their methylmercury content. About 40% of these fish smples showed Hg-concentrations of<=0,2 ppm, 50% of 0,21 - 0,5 ppm and 10% 0f 0,51 -1,03 ppm. The fraction of methylmercury in 6 fishes amounted between 6 and 72% of the total mercury content. (author)

  9. Secondary sex ratio in relation to exposures to polychlorinated biphenyls, dichlorodiphenyl dichloroethylene and methylmercury

    DEFF Research Database (Denmark)

    Timmermann, Clara Amalie Gade; Choi, Anna L; Petersen, Maria Skaalum

    2017-01-01

    This study was undertaken to assess the potential impact of maternal exposures to polychlorinated biphenyl (PCB), dichlorodiphenyl dichloroethylene (DDE) and methylmercury on the secondary sex ratios (the ratio of male to female live births) over a span of 23 years. The study includes prospective......% CI = 2-17%), respectively, of giving birth to a boy. In conclusion, maternal exposure to ΣPCB, DDE and methylmercury was associated with a slightly increased secondary sex ratio. The impact of paternal exposures could not be taken into account and deserves attention....

  10. The fatty acid profile of rainbow trout liver cells modulates their tolerance to methylmercury and cadmium

    International Nuclear Information System (INIS)

    Ferain, Aline; Bonnineau, Chloé; Neefs, Ineke; Rees, Jean François; Larondelle, Yvan; Schamphelaere, Karel A.C.De; Debier, Cathy

    2016-01-01

    Highlights: • The phospholipid composition of rainbow trout liver cells was successfully changed. • Cell phospholipids influenced methylmercury (MeHg) and cadmium (Cd) toxicity. • Cells enriched in 18:3n-3, 20:5n-3 or 22:5n-6 were more resistant to MeHg and Cd. • Cell enrichment in 22:6n-3 increased resistance to Cd but not MeHg. - Abstract: The polyunsaturated fatty acid (PUFA) composition of fish tissues, which generally reflects that of the diet, affects various cellular properties such as membrane structure and fluidity, energy metabolism and susceptibility to oxidative stress. Since these cellular parameters can play an important role in the cellular response to organic and inorganic pollutants, a variation of the PUFA supply might modify the toxicity induced by such xenobiotics. In this work, we investigated whether the cellular fatty acid profile has an impact on the in vitro cell sensitivity to two environmental pollutants: methylmercury and cadmium. Firstly, the fatty acid composition of the rainbow trout liver cell line RTL-W1 was modified by enriching the growth medium with either alpha-linolenic acid (ALA, 18:3n-3), eicosapentaenoic acid (EPA, 20:5n-3), docosahexaenoic acid (DHA, 22:6n-3), linoleic acid (LA, 18:2n-6), arachidonic acid (AA, 20:4n-6) or docosapentaenoic acid (DPA, 22:5n-6). These modified cells and their control (no PUFA enrichment) were then challenged for 24 h with increasing concentrations of methylmercury or cadmium. We observed that (i) the phospholipid composition of the RTL-W1 cells was profoundly modulated by changing the PUFA content of the growth medium: major modifications were a high incorporation of the supplemented PUFA in the cellular phospholipids, the appearance of direct elongation and desaturation metabolites in the cellular phospholipids as well as a change in the gross phospholipid composition (PUFA and monounsaturated fatty acid (MUFA) levels and n-3/n-6 ratio); (ii) ALA, EPA and DPA enrichment significantly

  11. The fatty acid profile of rainbow trout liver cells modulates their tolerance to methylmercury and cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Ferain, Aline, E-mail: aline.ferain@uclouvain.be [Institute of Life Sciences, Université catholique de Louvain, Place Croix du Sud 2/L7.05.08, B-1348 Louvain-la-Neuve (Belgium); Bonnineau, Chloé [Institute of Life Sciences, Université catholique de Louvain, Place Croix du Sud 2/L7.05.08, B-1348 Louvain-la-Neuve (Belgium); Irstea, UR MALY, Centre de Lyon-Villeurbanne, rue de la Doua 5/32108, F-69616 Villeurbanne (France); Neefs, Ineke; Rees, Jean François; Larondelle, Yvan [Institute of Life Sciences, Université catholique de Louvain, Place Croix du Sud 2/L7.05.08, B-1348 Louvain-la-Neuve (Belgium); Schamphelaere, Karel A.C.De [Laboratory of Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit, Ghent University, J. Plateaustraat 22, B-9000 Ghent (Belgium); Debier, Cathy [Institute of Life Sciences, Université catholique de Louvain, Place Croix du Sud 2/L7.05.08, B-1348 Louvain-la-Neuve (Belgium)

    2016-08-15

    Highlights: • The phospholipid composition of rainbow trout liver cells was successfully changed. • Cell phospholipids influenced methylmercury (MeHg) and cadmium (Cd) toxicity. • Cells enriched in 18:3n-3, 20:5n-3 or 22:5n-6 were more resistant to MeHg and Cd. • Cell enrichment in 22:6n-3 increased resistance to Cd but not MeHg. - Abstract: The polyunsaturated fatty acid (PUFA) composition of fish tissues, which generally reflects that of the diet, affects various cellular properties such as membrane structure and fluidity, energy metabolism and susceptibility to oxidative stress. Since these cellular parameters can play an important role in the cellular response to organic and inorganic pollutants, a variation of the PUFA supply might modify the toxicity induced by such xenobiotics. In this work, we investigated whether the cellular fatty acid profile has an impact on the in vitro cell sensitivity to two environmental pollutants: methylmercury and cadmium. Firstly, the fatty acid composition of the rainbow trout liver cell line RTL-W1 was modified by enriching the growth medium with either alpha-linolenic acid (ALA, 18:3n-3), eicosapentaenoic acid (EPA, 20:5n-3), docosahexaenoic acid (DHA, 22:6n-3), linoleic acid (LA, 18:2n-6), arachidonic acid (AA, 20:4n-6) or docosapentaenoic acid (DPA, 22:5n-6). These modified cells and their control (no PUFA enrichment) were then challenged for 24 h with increasing concentrations of methylmercury or cadmium. We observed that (i) the phospholipid composition of the RTL-W1 cells was profoundly modulated by changing the PUFA content of the growth medium: major modifications were a high incorporation of the supplemented PUFA in the cellular phospholipids, the appearance of direct elongation and desaturation metabolites in the cellular phospholipids as well as a change in the gross phospholipid composition (PUFA and monounsaturated fatty acid (MUFA) levels and n-3/n-6 ratio); (ii) ALA, EPA and DPA enrichment significantly

  12. Methylmercury bioaccumulation in an urban estuary: Delaware River USA.

    Science.gov (United States)

    Buckman, Kate; Taylor, Vivien; Broadley, Hannah; Hocking, Daniel; Balcom, Prentiss; Mason, Rob; Nislow, Keith; Chen, Celia

    2017-09-01

    Spatial variation in mercury (Hg) and methylmercury (MeHg) bioaccumulation in urban coastal watersheds reflects complex interactions between Hg sources, land use, and environmental gradients. We examined MeHg concentrations in fauna from the Delaware River estuary, and related these measurements to environmental parameters and human impacts on the waterway. The sampling sites followed a north to south gradient of increasing salinity, decreasing urban influence, and increasing marsh cover. Although mean total Hg in surface sediments (top 4cm) peaked in the urban estuarine turbidity maximum and generally decreased downstream, surface sediment MeHg concentrations showed no spatial patterns consistent with the examined environmental gradients, indicating urban influence on Hg loading to the sediment but not subsequent methylation. Surface water particulate MeHg concentration showed a positive correlation with marsh cover whereas dissolved MeHg concentrations were slightly elevated in the estuarine turbidity maximum region. Spatial patterns of MeHg bioaccumulation in resident fauna varied across taxa. Small fish showed increased MeHg concentrations in the more urban/industrial sites upstream, with concentrations generally decreasing farther downstream. Invertebrates either showed no clear spatial patterns in MeHg concentrations (blue crabs, fiddler crabs) or increasing concentrations further downstream (grass shrimp). Best-supported linear mixed models relating tissue concentration to environmental variables reflected these complex patterns, with species specific model results dominated by random site effects with a combination of particulate MeHg and landscape variables influencing bioaccumulation in some species. The data strengthen accumulating evidence that bioaccumulation in estuaries can be decoupled from sediment MeHg concentration, and that drivers of MeHg production and fate may vary within a small region.

  13. The effects of tributyltin oxide and deoxynivalenol on the transcriptome of the mouse thymoma cell line EL-4

    NARCIS (Netherlands)

    Schmeits, P.J.M.; Kol, S.; Loveren, van H.; Peijnenburg, A.A.C.M.; Hendriksen, P.J.M.

    2014-01-01

    The main goal of this study was to assess the potential of the mouse thymoma EL-4 cell line in screening for chemical induced immunotoxicity. Therefore, EL-4 cells were exposed to two well-known immunotoxicants, organotin compound tributyltin oxide (TBTO, 0.5 and 1 µM for 3 or 6 h) and the mycotoxin

  14. EFFECTS OF TRIBUTYLTIN ON CA2+ HOMEOSTASIS AND MECHANISMS CONTROLLING CELL CYCLING IN SEA URCHIN EGGS (R823881)

    Science.gov (United States)

    AbstractTributyltin (TBT) is one of the widespread organotins in the marine environment: we have investigated its cellular targets in the eggs of the marine invertebrate sea urchin Paracentrotus lividus. TBT was used at concentrations ranging from 10-9

  15. Bis(tributyltin)oxide (TBTO) decreases the food allergic response against peanut and ovalbumin in Brown Norway rats

    NARCIS (Netherlands)

    Jonge, J.D. de; Ezendam, J.; Knippels, L.M.J.; Odink, J.; Pourier, M.S.; Penninks, A.H.; Pieters, R.; Loveren, H. van

    2007-01-01

    Other factors than the allergen itself may be of importance in the development of food allergy. This report describes the influence of the immunosuppressive compound bis(tributyltin)oxide (TBTO), present in the food chain, on the development of food allergy to peanut or ovalbumin in Brown Norway

  16. Extracorporeal complexing hemodialysis system for the treatment of methylmercury poisoning. II. In vivo applications in the dog

    Energy Technology Data Exchange (ETDEWEB)

    Kostyniak, P.J.; Clarkson, T.W.; Abbasi, A.H.

    1977-01-01

    An extracorporeal regional complexing hemodialysis procedure is described which has been successfully applied for the enhancement of removal of methylmercury in the dog. The procedure utilizes the extracorporeal addition of cysteine to arterial blood entering a hemodialyzer, forming a large pool of complexed dialyzable methylmercury in plasma. Diffusion of this methylmercury complex across the dialyzer membrane into dialysate accounts for large amounts of methylmercury being removed from the animal. In conjunction with methylmercury removal, the majority of the infused cysteine is also removed resulting in comparatively low systemic doses of cysteine to the animal. At blood flow rates of 45 ml/min, and dialysate flow rates of approximately 550 ml/min, the mean percentage of methylmercury cleared from blood passing through the dialyzer was 39%. Rates of elimination of methylmercury from the dog could be increased by a factor of 100 during the extracorporeal regional complexing hemodialysis procedure. Regional collimated counting of radioactivity along the length of the dog revealed a decline in all areas including the head region. The procedure was void of any noticeable side effects during treatment or as evidence by histological evaluation of liver and kidney after treatment.

  17. The pH-dependent adsorption of tributyltin to charcoals and soot

    International Nuclear Information System (INIS)

    Fang Liping; Borggaard, Ole K.; Marcussen, Helle; Holm, Peter E.; Bruun Hansen, Hans Christian

    2010-01-01

    Widespread use of tributyltin (TBT) poses a serious environmental problem. Adsorption by black carbon (BC) may strongly affect its behavior. The adsorption of TBT to well characterized soot and two charcoals with specific surface area in the range of 62-111 m 2 g -1 have been investigated with main focus on pH effects. The charcoals but not soot possess acidic functional groups. TBT adsorption reaches maximum at pH 6-7 for charcoals, and at pH > 6 for soot. Soot has between 1.5 and 15 times higher adsorption density (0.09-1.77 μmol m -2 ) than charcoals, but charcoals show up to 17 times higher sorption affinities than soot. TBT adsorption is successfully described by a new pH-dependent dual Langmuir model considering electrostatic and hydrophobic adsorption, and pH effects on TBT speciation and BC surface charge. It is inferred that strong sorption of the TBTOH species to BC may affect TBT toxicity. - Tributyltin adsorption to black carbon increases at increasing pH but charcoal exhibits electrostatic and hydrophobic adsorption, whereas soot only adsorbs hydrophobically.

  18. The pH-dependent adsorption of tributyltin to charcoals and soot

    Energy Technology Data Exchange (ETDEWEB)

    Fang Liping, E-mail: fang@life.ku.d [Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark); Borggaard, Ole K.; Marcussen, Helle; Holm, Peter E.; Bruun Hansen, Hans Christian [Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark)

    2010-12-15

    Widespread use of tributyltin (TBT) poses a serious environmental problem. Adsorption by black carbon (BC) may strongly affect its behavior. The adsorption of TBT to well characterized soot and two charcoals with specific surface area in the range of 62-111 m{sup 2} g{sup -1} have been investigated with main focus on pH effects. The charcoals but not soot possess acidic functional groups. TBT adsorption reaches maximum at pH 6-7 for charcoals, and at pH > 6 for soot. Soot has between 1.5 and 15 times higher adsorption density (0.09-1.77 {mu}mol m{sup -2}) than charcoals, but charcoals show up to 17 times higher sorption affinities than soot. TBT adsorption is successfully described by a new pH-dependent dual Langmuir model considering electrostatic and hydrophobic adsorption, and pH effects on TBT speciation and BC surface charge. It is inferred that strong sorption of the TBTOH species to BC may affect TBT toxicity. - Tributyltin adsorption to black carbon increases at increasing pH but charcoal exhibits electrostatic and hydrophobic adsorption, whereas soot only adsorbs hydrophobically.

  19. Perinatal exposure to low doses of tributyltin chloride reduces sperm count and quality in mice.

    Science.gov (United States)

    Si, Jiliang; Li, Peng; Xin, Quanbing; Li, Xuewen; An, Lihong; Li, Jie

    2015-01-01

    Exposure to endocrine disruptors (EDs) during early development might lead to adverse health outcomes later in life. Tributyltin (TBT), a proven ED, is widely used in consumer goods and industrial products. Herein we demonstrate the effects of low doses of tributyltin chloride (TBTCl) on reproduction of male KM mice. Pregnant mice were administered by gavage with 0, 1, 10, or 100 μg TBTCl/kg body weight/day from day 6 of pregnancy through the period of lactation. TBTCl dramatically decreased sperm counts and motility on postnatal days (PNDs) 49 and 152. Meanwhile, a significant increase in sperm abnormality was observed in exposed mice on PND 49, but comparable to that in the control on PND 152. The histopathological analysis of testes of treated animals showed a dose-dependent increase in sloughing of germ cells in seminiferous tubules. Mice treated with 10 μg TBTCl/kg exhibited decreased intratesticular 17β-estradiol (E2) levels on PND 49, and then followed by an obvious recovery on PND 152. While, no significant differences in serum E2, testosterone (T) levels and intratesticular T levels were detectable between control and TBTCl-exposed offspring at the sacrifice. These results suggest that perinatal TBTCl exposure is implicated in causing long lasting alterations in male reproductive system and these changes may persist far into adulthood. © 2013 Wiley Periodicals, Inc.

  20. Lysosomal membrane stability of the mussel, Mytilus galloprovincialis (L.), as a biomarker of tributyltin exposure.

    Science.gov (United States)

    Okoro, Hussein K; Snyman, Reinette G; Fatoki, Olalekan S; Adekola, Folahan A; Ximba, Bhekumusa J; Slabber, Michelle Y

    2015-05-01

    The effect of tributyltin (TBT) on the stability of hemocytic lysosome membranes of the mussel, Mytilus galloprovincialis, and the use thereof as a biomarker of TBT-induced stress, was investigated. Mussels were exposed to 0.1 and 1.0 µg/L tributyltin respectively for 4 weeks. Lysosomal membrane stability of hemocytes was tested weekly by means of the neutral red retention time (NRRT) assay, after which the mussel samples were analyzed for TBT content. The two exposed groups exhibited significantly increased (p < 0.05) whole body TBT concentrations with concomitant significant decreases (p < 0.05) in NRRT (R(2) values of 0.85 and 0.971 for lower and higher exposure groups, respectively). The higher exposure group showed a typical dose-response curve. For the control, no TBT was detected and NRRT remained stable. It was concluded that the NRRT assay could be considered as a useful technique, and lysosomal membrane destabilization a useful early warning and cellular biomarker of stress due to TBT exposure in M. galloprovincialis.

  1. Effects of tributyltin (TBT) on Xenopus tropicalis embryos at environmentally relevant concentrations.

    Science.gov (United States)

    Guo, Suzhen; Qian, Lijuan; Shi, Huahong; Barry, Terence; Cao, Qinzhen; Liu, Junqi

    2010-04-01

    Tributyltin (TBT) has been widely used as a biocide in antifouling paints and is a known endocrine disrupting chemical. In this paper, we exposed embryos of Xenopus tropicalis to 50-400ngL(-1) tributyltin chloride. TBT significantly decreased the survival rate, reduced the body length and retarded the development of embryos after 24, 36 and 48h of exposure. These effects of TBT were concentration- and time-dependent. Embryos treated with TBT showed multiple malformations. The most obvious alterations were abnormal eyes, enlarged proctodaeum, narrow fins, and skin hypopigmentation. Enlarged proctodaeum and narrow fins were mainly observed after 36 and 48h of exposure. The loss of eye pigmentation or the absence of external eyes occurred after 24 and 36h of exposure, while extended lenses or edemas of eyes were more commonly observed after 48h of exposure. Additional malformations included: small anterior region of heads, pericardial edemas, enlarged trunks, and bent tails. These results suggested that TBT is very toxic to X. tropicalis embryos at environmentally relevant concentrations.

  2. Actively Shaken In-Situ Passive Sampler Platform for Methylmercury and Organics

    Science.gov (United States)

    2016-02-01

    from a risk standpoint, methylmercury (MeHg), and to identify a polymer partitioning approach by developing and testing a range of polymeric ...an assortment of thiolated polymers for use in pharmaceuticals, where their ability to form sulfide bonds confers mucoadhesive properties that...agarose. The thiolated polymers tested in this set leached sulfur into solution, causing analytical interferences and confounding the results. For

  3. Methylmercury determination in sediments and fish tissues from the Nerbioi-Ibaizabal estuary (Basque Country, Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Sanz Landaluze, Jon; Diego, Alberto de; Raposo, Juan Carlos; Madariaga, Juan Manuel

    2004-04-15

    The analysis of methylmercury in extracts from environmental solid samples by gas chromatography coupled to microwave induced plasma atomic emission spectrometry (GC-MIP/AES) after the ethylation of the extract and the preconcentration of the volatile products in hexane has been critically investigated. In order to correct potential sources of random error along the analytical procedure affecting the overall repeatability of the analysis, the use of the inorganic mercury naturally occurring in the sample as internal standard in the analysis of methylmercury is proposed. A study to establish the best conditions to achieve a quantitative recovery of methylmercury without damaging its chemical structure has also been carried out. Magnetic stirring (without heating) of the sediment or fish tissue with 2 mol dm{sup -3} HNO{sub 3} or 10% methanolic KOH, respectively, during 90 min has been considered as the most effective procedure to release methylmercury preserving its structure. The proposed method has been validated using certified reference materials (CRM-580, CRM-463 and DOLT-2), assessing its quality in terms of accuracy, repeatability and detection limit. Finally, several sediment and fish samples collected in the estuary of the Nerbioi-Ibaizabal (Bilbao, Basque Country) have been analyzed following the procedures proposed. The results obtained show the validity of the proposed method to analyze real samples.

  4. Methylmercury in water, sediment, and invertebrates in created wetlands of Rouge Park, Toronto, Canada

    International Nuclear Information System (INIS)

    Sinclair, Kathleen A.; Xie Qun; Mitchell, Carl P.J.

    2012-01-01

    Thousands of hectares of wetlands are created annually because wetlands provide beneficial ecosystem services. Wetlands are also key sites for production of the bioaccumulative neurotoxin methylmercury (MeHg), but little is known about MeHg production in created systems. Here, we studied methylmercury in sediment, water, and invertebrates in created wetlands of various ages. Sediment MeHg reached 8 ng g −1 in the newest wetland, which was significantly greater than in natural, control wetlands. This trend was mirrored in several invertebrate taxa, whose concentrations reached as high as 1.6 μg g −1 in the newest wetland, above levels thought to affect reproduction in birds. The MeHg concentrations in created wetland invertebrate taxa generally decreased with increasing wetland age, possibly due to a combination of deeper anoxia and less organic matter accumulation in younger wetlands. A short-term management intervention and/or improved engineering design may be necessary to reduce the mercury-associated risk in newly created wetlands. - Highlights: ► Investigated methylmercury accumulation in created wetland ecosystems. ► Concentrations and bioaccumulation significantly elevated in new created wetlands. ► Short-term effect may be due to deeper anoxia, less organic matter in new wetlands. ► Intervention or improved design required to reduce short-term ecological risk. - Sediment methylmercury concentrations and bioaccumulation in many invertebrate taxa are significantly elevated in newly created wetlands.

  5. Determination of methylmercury in cryptogams by means of GC-AFS using enzymatic hydrolysis

    Czech Academy of Sciences Publication Activity Database

    Coufalík, Pavel; Meszarosová, N.; Coufalíková, K.; Zvěřina, O.; Komárek, J.

    2018-01-01

    Roč. 140 (2018), s. 8-13 ISSN 0026-265X Institutional support: RVO:68081715 Keywords : methylmercury * cryptogam * GC-AFS Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 3.034, year: 2016

  6. Phytoremediation Of Mercury And Methylmercury Contaminated Sediments By Water Hyacinth (Eichhornia crassipes)

    Science.gov (United States)

    Phytoremediation has potential to be implemented at mercury (Hg) and methylmercury (MeHg) contaminated sites. Water hyacinths (Eichhornia crassipes) were investigated for their ability to assimilate Hg and MeHg into plant biomass, in both aquatic and sediment-associated f...

  7. Methylmercury declines in a boreal peatland when experimental sulfate deposition decreases

    Science.gov (United States)

    Jill K. Coleman Wasik; Carl P.J. Mitchell; Daniel R. Engstrom; Edward B. Swain; Bruce A. Monson; Steven J. Balogh; Jeffrey D. Jeremiason; Brian A. Branfireun; Susan L. Eggert; Randall K. Kolka; James E. Almendinger

    2012-01-01

    Between 2001 and 2008 we experimentally manipulated atmospheric sulfate-loading to a small boreal peatland and monitored the resulting short and long-term changes in methylmercury (MeHg) production. MeHg concentrations and %MeHg (fraction of total-Hg (HgT) present as MeHg) in the porewaters of the experimental treatment reached peak values within...

  8. Methylmercury and brain development: imprecision and underestimation of developmental neurotoxicity in humans

    DEFF Research Database (Denmark)

    Grandjean, Philippe; Herz, Katherine T

    2011-01-01

    Methylmercury is now recognized as an important developmental neurotoxicant, though this insight developed slowly over many decades. Developmental neurotoxicity was first reported in a Swedish case report in 1952, and from a serious outbreak in Minamata, Japan, a few years later. Whereas the infant...

  9. Mercury and methylmercury in hair of selected groups of Czech population

    Czech Academy of Sciences Publication Activity Database

    Wranová, K.; Čejchanová, M.; Spěváčková, V.; Korunová, Vlasta; Vobecký, Miloslav; Spěváček, V.

    2009-01-01

    Roč. 17, č. 1 (2009), s. 36-40 ISSN 1210-7778 R&D Projects: GA MZd NR8955 Institutional research plan: CEZ:AV0Z40310501 Keywords : inorganic mercury * methylmercury * hair Subject RIV: CB - Analytical Chemistry, Separation

  10. Streamwater fluxes of total mercury and methylmercury into and out of Lake Champlain

    International Nuclear Information System (INIS)

    Shanley, James B.; Chalmers, Ann T.

    2012-01-01

    From 2000 to 2004, we sampled for total mercury (THg) and methylmercury (MeHg) in inlet streams to Lake Champlain, targeting high flow periods to capture increases in THg and MeHg concentrations with increasing flow. We used these data to model stream THg and MeHg fluxes for Water Years 2001 through 2009. In this mountainous forested basin with a high watershed-to-lake area ratio of 18, fluvial export from the terrestrial watershed was the dominant source of Hg to the lake. Unfiltered THg and MeHg fluxes were dominated by the particulate fraction; about 40% of stream THg was in the filtered ( −2 yr −1 , or about 13% of atmospheric Hg wet and dry deposition to the basin. THg export from the lake represented only about 3% of atmospheric Hg input to the basin. - Highlights: ► We monitored total mercury and methylmercury in major tributaries to Lake Champlain. ► Mercury and methylmercury export was primarily as particulates during high flow. ► Only 13% of atmospheric total mercury input reached the lake via streams. ► Only 3% of atmospheric total mercury input reached the lake outlet. - Eighty-seven percent of total mercury deposition to the Lake Champlain basin is retained in the terrestrial basin; stream export of total and methylmercury to the lake is primarily in the particulate phase.

  11. Effects of Injected Methylmercury on the Hatching of Common Loon (Gavia immer) Eggs

    Science.gov (United States)

    To determine the level of in ovo methylmercury (MeHg) exposure that results in detrimental effects on fitness and survival of loon embryos and hatched chicks, we conducted a field study in which we injected eggs with various doses of MeHg on day 4 of incubation. Eggs were collect...

  12. Performance of laboratories in speciation analysis in seafood – Case of methylmercury and inorganic arsenic

    DEFF Research Database (Denmark)

    Baer, Ines; Baxter, Malcolm; Devesa, Vicenta

    2011-01-01

    arsenic analysis. Results for inorganic arsenic were spread, but not method dependant. The measurand seems to be difficult to analyse in this matrix and possible method issues were identified. Methylmercury results were satisfactory, but not many laboratories perform this type of analysis because...

  13. Determination of total mercury and methylmercury in human head hair by radiochemical methods of analysis

    International Nuclear Information System (INIS)

    Vasconcellos, M.B.A.; Saiki, M.; Paletti, G.; Baruzzi, R.G.; Rodrigues, D.A.; Cuten, J.

    1995-01-01

    Total mercury has been determined by instrumental neutron activation analysis in the hair of several Indian tribes living in the Xingu Park, located in the Amazonic region of Brazil. Methylmercury and total mercury have been determined in selected samples using cold vapour atomic absorption spectroscopy, at the Nuclear Chemistry Department, Jozef Stefan Institute, Ljubliana, Slovenia. Mercury levels were found to be much higher in the Indian hair samples as compared to the samples from the control population. The arithmetic and geometric means for total mercury in the Indian hair samples ranged from 10 to 20 ppm, compared to values of about 1 ppm for the means of the control group. The results obtained for methylmercury have shown that the majority of the mercury is present in the hair of the Indians as the organic form. The Indian study populations living in the Xingu Park can thus be considered as being at risk with regards to contamination by mercury. With the aim of applying neutron activation analysis for the determination of methylmercury in hair, experiments were done at the IEA-R1 nuclear research reactor irradiating cysteine- and also thioacetamide- impregnated filter papers, on which a methylmercury solution was pipetted. The results obtained have shown that all the mercury was lost from the cysteine-impregnated paper and about 90 % of the mercury remained on the paper impregnated with thioacetamide. (author)

  14. The oral bioavailability and toxicokinetics of methylmercury in common loon (Gavia immer) chicks

    Science.gov (United States)

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

    2002-01-01

    We compared the toxicokinetics of methylmercury in captive common loon chicks during two time intervals to assess the impact of feather growth on the kinetics of mercury. We also determined the oral bioavailability of methylmercury during these trials to test for age-related changes. The blood concentration-time curves for individuals dosed during feather development (initiated 35 days post hatch) were best described by a one-compartment toxicokinetic model with an elimination half-life of 3 days. The data for birds dosed following completion of feather growth (84 days post hatch) were best fitted by a two-compartment elimination model that includes an initial rapid distribution phase with a half-life of 0.9 days, followed by a slow elimination phase with a half-life of 116 days. We determined the oral bioavailability of methylmercury during the first dosing interval by comparing the ratios of the area under the blood concentration-time curves (AUC0→∞) for orally and intravenously dosed chicks. The oral bioavailability of methylmercury during the first dosing period was 0.83. We also determined bioavailability during both dosing periods using a second measure because of irregularities with intravenous results in the second period. This second bioavailability measure estimated the percentage of the dose that was deposited in the blood volume (f), and the results show that there was no difference in bioavailability among dosing periods. The results of this study highlight the importance of feather growth on the toxicokinetics of methylmercury.

  15. Mercury and methylmercury concentrations and loads in the Cache Creek watershed, California

    International Nuclear Information System (INIS)

    Domagalski, Joseph L.; Alpers, Charles N.; Slotton, Darell G.; Suchanek, Thomas H.; Ayers, Shaun M.

    2004-01-01

    Concentrations and loads of total mercury and methylmercury were measured in streams draining abandoned mercury mines and in the proximity of geothermal discharge in the Cache Creek watershed of California during a 17-month period from January 2000 through May 2001. Rainfall and runoff were lower than long-term averages during the study period. The greatest loading of mercury and methylmercury from upstream sources to downstream receiving waters, such as San Francisco Bay, generally occurred during or after winter rainfall events. During the study period, loads of mercury and methylmercury from geothermal sources tended to be greater than those from abandoned mining areas, a pattern attributable to the lack of large precipitation events capable of mobilizing significant amounts of either mercury-laden sediment or dissolved mercury and methylmercury from mine waste. Streambed sediments of Cache Creek are a significant source of mercury and methylmercury to downstream receiving bodies of water. Much of the mercury in these sediments is the result of deposition over the last 100-150 years by either storm-water runoff, from abandoned mines, or continuous discharges from geothermal areas. Several geochemical constituents were useful as natural tracers for mining and geothermal areas, including the aqueous concentrations of boron, chloride, lithium and sulfate, and the stable isotopes of hydrogen and oxygen in water. Stable isotopes of water in areas draining geothermal discharges showed a distinct trend toward enrichment of 18 O compared with meteoric waters, whereas much of the runoff from abandoned mines indicated a stable isotopic pattern more consistent with local meteoric water

  16. Mercury and methylmercury concentrations and loads in the Cache Creek watershed, California

    Energy Technology Data Exchange (ETDEWEB)

    Domagalski, Joseph L.; Alpers, Charles N.; Slotton, Darell G.; Suchanek, Thomas H.; Ayers, Shaun M

    2004-07-05

    Concentrations and loads of total mercury and methylmercury were measured in streams draining abandoned mercury mines and in the proximity of geothermal discharge in the Cache Creek watershed of California during a 17-month period from January 2000 through May 2001. Rainfall and runoff were lower than long-term averages during the study period. The greatest loading of mercury and methylmercury from upstream sources to downstream receiving waters, such as San Francisco Bay, generally occurred during or after winter rainfall events. During the study period, loads of mercury and methylmercury from geothermal sources tended to be greater than those from abandoned mining areas, a pattern attributable to the lack of large precipitation events capable of mobilizing significant amounts of either mercury-laden sediment or dissolved mercury and methylmercury from mine waste. Streambed sediments of Cache Creek are a significant source of mercury and methylmercury to downstream receiving bodies of water. Much of the mercury in these sediments is the result of deposition over the last 100-150 years by either storm-water runoff, from abandoned mines, or continuous discharges from geothermal areas. Several geochemical constituents were useful as natural tracers for mining and geothermal areas, including the aqueous concentrations of boron, chloride, lithium and sulfate, and the stable isotopes of hydrogen and oxygen in water. Stable isotopes of water in areas draining geothermal discharges showed a distinct trend toward enrichment of {sup 18}O compared with meteoric waters, whereas much of the runoff from abandoned mines indicated a stable isotopic pattern more consistent with local meteoric water.

  17. Methylmercury compounds - main areas of contamination on a transsect of the river Elbe

    International Nuclear Information System (INIS)

    Hintelmann, H.; Wilken, R.D.

    1994-01-01

    The river Elbe and some of its tributaries are worldwide one of the most mercury polluted river systems. They are not only polluted by inorganic mercury compouns, but the contents of the highly toxic methylmercury compounds are also elevated. In order to determine the low levels of methylmercury compounds usually observed in sediments, a new HPLC/AFS-coupling was developed. In an oxidation/reduction interface the mercury species eluting from the HPLC collumn are transformed continuously to elemental mercury, which is then detected on-line by a highly sensitive atomic fluorescence spectrophotometer. The detection limit for the analysis of organic mercury species in sediments after extraction with hydrochloric acid/toluene, preconcentration and determination by HPLC/AFS is 0.1 μg/kg d. w. Hence, uncontaminated samples with very low methylmercury compounds contents could also be successfully analyzed. Main areas of total mercury contamination in the Elbe system were in the tributary rivers Saale and Mulde, with contents of up to 112 mg/kg d. w. but important emitters were also found in the Czech Republic (CR). This contamination was followed downstream to the Hamburg area and dropped to a background level of 0.06 mg/kg d. w. in the German Bight. The highest content of methylmercury compounds (119 μg/kg d. w.) was measured again in the river Mulde. The levels of methylmercury compounds were generally high at sites where the microbial activity was stimulated by high contents of organic matter, indicating a biotic methylation of mercury. The organic substrates originated either from municipal (sewage plants) or industrial sources (pulp mill effluents). (orig.) [de

  18. Determination of methylmercury in marine sediment samples: Method validation and occurrence data

    International Nuclear Information System (INIS)

    Carrasco, Luis; Vassileva, Emilia

    2015-01-01

    Highlights: • A method for MeHg determination at trace level in marine sediments is completely validated. • Validation is performed according to ISO-17025 and Eurachem guidelines. • The extraction efficiency of four sample preparation procedures is evaluated. • The uncertainty budget is used as a tool for evaluation of main uncertainty contributors. • Comparison with independent methods yields good agreement within stated uncertainty. - Abstract: The determination of methylmercury (MeHg) in sediment samples is a difficult task due to the extremely low MeHg/THg (total mercury) ratio and species interconversion. Here, we present the method validation of a cost-effective fit-for-purpose analytical procedure for the measurement of MeHg in sediments, which is based on aqueous phase ethylation, followed by purge and trap and hyphenated gas chromatography–pyrolysis–atomic fluorescence spectrometry (GC–Py–AFS) separation and detection. Four different extraction techniques, namely acid and alkaline leaching followed by solvent extraction and evaporation, microwave-assisted extraction with 2-mercaptoethanol, and acid leaching, solvent extraction and back extraction into sodium thiosulfate, were examined regarding their potential to selectively extract MeHg from estuarine sediment IAEA-405 certified reference material (CRM). The procedure based on acid leaching with HNO 3 /CuSO 4 , solvent extraction and back extraction into Na 2 S 2 O 3 yielded the highest extraction recovery, i.e., 94 ± 3% and offered the possibility to perform the extraction of a large number of samples in a short time, by eliminating the evaporation step. The artifact formation of MeHg was evaluated by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC–ICP–MS), using isotopically enriched Me 201 Hg and 202 Hg and it was found to be nonexistent. A full validation approach in line with ISO 17025 and Eurachem guidelines was followed

  19. Determination of methylmercury in marine sediment samples: Method validation and occurrence data

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco, Luis; Vassileva, Emilia, E-mail: e.vasileva-veleva@iaea.org

    2015-01-01

    Highlights: • A method for MeHg determination at trace level in marine sediments is completely validated. • Validation is performed according to ISO-17025 and Eurachem guidelines. • The extraction efficiency of four sample preparation procedures is evaluated. • The uncertainty budget is used as a tool for evaluation of main uncertainty contributors. • Comparison with independent methods yields good agreement within stated uncertainty. - Abstract: The determination of methylmercury (MeHg) in sediment samples is a difficult task due to the extremely low MeHg/THg (total mercury) ratio and species interconversion. Here, we present the method validation of a cost-effective fit-for-purpose analytical procedure for the measurement of MeHg in sediments, which is based on aqueous phase ethylation, followed by purge and trap and hyphenated gas chromatography–pyrolysis–atomic fluorescence spectrometry (GC–Py–AFS) separation and detection. Four different extraction techniques, namely acid and alkaline leaching followed by solvent extraction and evaporation, microwave-assisted extraction with 2-mercaptoethanol, and acid leaching, solvent extraction and back extraction into sodium thiosulfate, were examined regarding their potential to selectively extract MeHg from estuarine sediment IAEA-405 certified reference material (CRM). The procedure based on acid leaching with HNO{sub 3}/CuSO{sub 4}, solvent extraction and back extraction into Na{sub 2}S{sub 2}O{sub 3} yielded the highest extraction recovery, i.e., 94 ± 3% and offered the possibility to perform the extraction of a large number of samples in a short time, by eliminating the evaporation step. The artifact formation of MeHg was evaluated by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC–ICP–MS), using isotopically enriched Me{sup 201}Hg and {sup 202}Hg and it was found to be nonexistent. A full validation approach in line with ISO 17025 and

  20. Disruption of brain mitochondrial calcium sequestration by methylmercury

    International Nuclear Information System (INIS)

    Levesque, P.C.; Atchison, W.D.

    1991-01-01

    In vitro effects of methylmercury (MeHg) on Ca2+ transport and respiratory control of mitochondria isolated from rat forebrain were examined to determine whether MeHg disrupted sequestration of Ca2+ by neuronal mitochondria. Uptake of 45Ca2+ by mitochondria and release of 45Ca2+ from preloaded mitochondria were measured in the presence and absence of ATP. Release of 45Ca2+ from preloaded mitochondria by MeHg was measured in the presence and absence of ruthenium red (RR), a putative inhibitor of the mitochondrial Ca2+ uptake uniporter. During incubation intervals ranging from 10 sec to 5 min, 10 microM MeHg reduced mitochondrial uptake of 45Ca2+ by about 50% and 100 microM MeHg completely prevented 45Ca2+ uptake. These effects of MeHg occurred in both the presence and absence of ATP. Exposure of mitochondria preloaded with 45Ca2+ to either 10 microM or 100 microM MeHg for 10 sec resulted in increased efflux of 45Ca2+ of 10% and 65%, respectively, in both the absence and presence of ATP. Loading mitochondria with 45Ca2+ in the presence of 20 microM RR reduced total uptake of 45Ca2+ and greatly attenuated MeHg-induced release of 45Ca2+ from mitochondria. RR did not inhibit the effects of MeHg on Ca2+ release by merely preventing the binding of MeHg to mitochondria because RR did not alter mitochondrial binding of methyl[203Hg]. The ratio of state 3 to state 4 respiration (respiratory control ratio) was measured as a means of assessing functional integrity of isolated mitochondria in the absence and presence of MeHg. Control ratios of from 3 to 5 were only marginally reduced by 2 microM MeHg but were greatly reduced by 10 and 20 microM MeHg

  1. Evaluation of methylmercury biotransformation using rat liver slices

    Energy Technology Data Exchange (ETDEWEB)

    Yasutake, A. [Biochemistry Section, National Inst. for Minamata Disease, Minamata, Kumamoto (Japan); Hirayama, K. [Kumamoto University College of Medical Science, Kuhonji (Japan)

    2001-09-01

    To examine the demethylation reaction of methylmercury (MeHg) in rat liver, slices prepared from MeHg-treated rats were incubated in L-15 medium under 95% O{sub 2}/5% CO{sub 2} atmosphere. During the incubation, the amount of inorganic Hg in the slices markedly increased in a time-dependent manner, although the concentration of total Hg remained unchanged. Since the C-Hg bond in MeHg was demonstrated to be cleaved by the action of some reactive oxygen species, the effects on MeHg demethylation of several reagents that could modify reactive oxygen production were examined in the present system. Methylviologen was found to be an effective enhancer of the demethylation reaction with only a minor effect on lipid peroxidation. On the other hand, ferrous ion added to the medium showed no effect on demethylation in the presence or absence of methylviologen, although lipid peroxide levels were increased significantly by ferrous ion. Similarly, deferoxamine mesylate, which effectively suppressed the increase in lipid peroxide levels, also had no effect on demethylation. Furthermore, hydroxy radical scavengers, such as mannitol and dimethylsulfoxide, had no effect on inorganic Hg production. Rotenone, an inhibitor of complex I in the mitochondrial electron transport system, increased levels of both inorganic Hg and lipid peroxide. However, other inhibitors, such as antimycin A, myxothiazole and NaCN, significantly suppressed the demethylation reaction. Cell fractionation of the MeHg-treated rat liver revealed that the ratio of inorganic Hg to total Hg was highest in the mitochondrial fraction. Furthermore, superoxide anion could degrade MeHg in an organic solvent but not in water. These results suggested that the demethylation of MeHg by the liver slice would proceed with the aid of superoxide anion produced in the electron transfer system at the hydrophobic mitochondrial inner membrane. Furthermore, the involvement of hydroxy radicals, which have been demonstrated to be

  2. Hippocampal developmental vulnerability to methylmercury extends into prepubescence

    Directory of Open Access Journals (Sweden)

    Maryann eObiorah

    2015-05-01

    Full Text Available The developing brain is sensitive to environmental toxicants such as methylmercury (MeHg, to which humans are exposed via contaminated seafood. Prenatal exposure in children is associated with learning, memory and IQ deficits, which can result from hippocampal dysfunction. To explore underlying mechanisms, we have used the postnatal day (P7 rat to model the third trimester of human gestation. We previously showed that a single low exposure (0.6 µg/gbw that approaches human exposure reduced hippocampal neurogenesis in the dentate gyrus (DG 24 hours later, including later proliferation and memory in adolescence. Yet, the vulnerable stem cell population and period of developmental vulnerability remain undefined. In this study, we find that P7 exposure of stem cells has long-term consequences for adolescent neurogenesis. It reduced the number of mitotic S-phase cells (BrdU, especially those in the highly proliferative Tbr2+ population, and immature neurons (Doublecortin in adolescence, suggesting partial depletion of the later stem cell pool. To define developmental vulnerability to MeHg in prepubescent (P14 and adolescent (P21 rats, we examined acute 24 h effects of MeHg exposure on mitosis and apoptosis. We found that low exposure did not adversely impact neurogenesis at either age, but that a higher exposure (5 µg/gbw at P14 reduced the total number of neural stem cells (Sox2+ by 23% and BrdU+ cells by 26% in the DG hilus, suggesting that vulnerability diminishes with age. To see if these effects may reflect changes in MeHg transfer across the blood brain barrier, we assessed Hg content in the hippocampus after peripheral injection and found that similar levels (~800 ng/gm were obtained at 24 h at both P14 and P21, declining in parallel, suggesting that changes in vulnerability depend more on local tissue and cellular mechanisms. Together, we show that MeHg vulnerability depends on age, and that early exposure impairs later neurogenesis in

  3. Low level methylmercury exposure affects neuropsychological function in adults

    Directory of Open Access Journals (Sweden)

    Platt Illeane

    2003-06-01

    Full Text Available Abstract Background The neurotoxic effects of methylmercury (MeHg have been demonstrated in both human and animal studies. Both adult and fetal brains are susceptible to the effects of MeHg toxicity. However, the specific effects of adult exposures have been less well-documented than those of children with prenatal exposures. This is largely because few studies of MeHg exposures in adults have used sensitive neurological endpoints. The present study reports on the results of neuropsychological testing and hair mercury concentrations in adults (>17 yrs living in fishing communities of Baixada Cuiabana (Mato Grosso in the Pantanal region of Brazil. Methods A cross-sectional study was conducted in six villages on the Cuiaba River. Participants included 129 men and women older than 17 years of age. They were randomly selected in proportion to the age range and number of inhabitants in each village. Questionnaire information was collected on demographic variables, including education, occupation, and residence history. Mercury exposure was determined by analysis of hair using flameless atomic absorption spectrophotometry. The neurocognitive screening battery included tests from the Wechsler Memory Scale and the Wechsler Adult Intelligence Scale, Concentrated Attention Test of the Toulouse-Pierron Factorial Battery, the Manual Ability Subtests of the Tests of Mechanical Ability, and the Profile of Mood States. Results Mercury exposures in this population were associated with fish consumption. The hair mercury concentration in the 129 subjects ranged from 0.56 to 13.6 μg/g; the mean concentration was 4.2 ± 2.4 micrograms/g and the median was 3.7 μg/g. Hair mercury levels were associated with detectable alterations in performance on tests of fine motor speed and dexterity, and concentration. Some aspects of verbal learning and memory were also disrupted by mercury exposure. The magnitude of the effects increased with hair mercury concentration

  4. Determination of total and methylmercury compounds in the IAEA human hair intercomparison samples - Experience of the IAEA-MEL

    International Nuclear Information System (INIS)

    Horvat, M.; Liang, L.; Mandic, V.

    1995-01-01

    The programme of this CRP is focused on the analyses of human hair samples. There are only two human hair samples certified for total mercury, and no RMs for methylmercury compounds is available. One of the main objectives of this CRP is to produce, through the IAEA AQCS Programme, a human hair intercomparison material for quality assurance requirements in population monitoring programmes for total and methylmercury exposure. Through the reporting period, MESL has introduced a new method for simultaneous determination of total and methylmercury in biological samples. As the laboratory has close collaboration with the CRP's Reference Laboratory in Ljubljana, Slovenia, it has also been actively involved in the quality assurance component of this CRP. This report represents a summary on the results for total and methylmercury in two intercomparison samples, IAEA-085 and IAEA-086 using newly developed method

  5. Male cerebral palsy hospitalization as a potential indicator of neurological effects of methylmercury exposure in Great Lakes communities

    International Nuclear Information System (INIS)

    Gilbertson, Michael

    2004-01-01

    Perinatal exposure to methylmercury is known to result in severe neurological effects on the developing fetus and infant, including cerebral palsy, mental retardation, and seizures. Males are more susceptible than females to neurological damage from perinatal methylmercury exposures. Preliminary analyses of data and statistics for the hospitalization rates of males for cerebral palsy in the 17 Canadian Areas of Concern in the Great Lakes basin indicate a possible geographic association with locations with elevated mercury from natural or industrial sources

  6. [Improvement of the method for methylmercury determination in aquatic products using liquid chromatography online coupled with atomic fluorescence spectrometry].

    Science.gov (United States)

    Shang, Xiaohong; Zhao, Yunfeng; Zhang, Lei; Li, Xiaowei; Wu, Yongning

    2011-07-01

    The improvement method was developed for methylmercury determination using liquid chromatography online coupled with cold vapor atomic fluorescence spectrometry (LC-CV-AFS). Cysteine was used as complexing agent in mobile phase instead of mercaptoethanol. Under the optimized conditions, baseline separation of mercury species could be achieved within 8 min on a C18 column with a mobile phase of 5% (v/v) acetonitrile-1 g/L L-cysteine-50 mmol/L ammonium acetate aqueous solution. The linear range of calibration curve of methylmercury was 1-50 microg/L and the limit of detection (S/N = 3) for methylmercury was 0.3 microg/L. Ultrasonication assisted hydrochloric acid extraction was used to extract methylmercury from seafood samples. The sample extract was cleaned up by a C18 solid phase extraction (SPE) cartridge. For validation of the method, certified reference materials and spiked seafood samples were analyzed. The determined methylmercury contents of certified reference materials NIST1566b, BCR464 and GBW10029 agreed well with the certified values. The determined methylmercury values for Food Analysis Performance Assessment Scheme (FAPAS) sample 07115 were satisfied. The recoveries of methylmercury in seafood samples at three spiked levels (10, 50 and 500 microg/kg) ranged from 89% to 112%, including cooked seafood food. The precision of the method based on relative standard deviation (RSD) was not more than 7%. The present method of LC-CV-AFS is accurate, sensitive, simple, and can meet the demand of methylmercury determination in seafood.

  7. Long term impact of the endocrine disruptor tributyltin on male fertility following a single acute exposure.

    Science.gov (United States)

    Mitra, Sumonto; Srivastava, Ankit; Khandelwal, Shashi

    2017-10-01

    Declining rate of human fertility is a growing concern, where lifestyle and environmental factors play an important role. We recently demonstrated that tributyltin (TBT), an omnipresent endocrine disruptor, affects testicular cells in vitro. In this study, male Wistar rats were gavaged a single dose of 10, 20, and 30 mg/kg TBT-chloride (TBTC) (to mimic accidental exposure in vivo) and sacrificed on day 3 and day 7, respectively. TBT bioavailability was evaluated by estimating total tin content, and essential metal levels were analyzed along with redox molecules (ROS and GSH/GSSG) to understand the effect on physiological conditions. Blood-testicular barrier (BTB) disruption, levels of associated proteins and activity of proteolytic enzymes were evaluated to understand the effect on BTB. Histological analysis of tissue architecture and effect on protein expression of steroidogenic, stress and apoptotic markers were also evaluated. Widespread TBTC pollution can be an eventual threat to male fertility worldwide. © 2017 Wiley Periodicals, Inc.

  8. Ecological impacts of tributyltin on estuarine communities in the Hastings River, NSW Australia

    International Nuclear Information System (INIS)

    Roach, A.C.; Wilson, S.P.

    2009-01-01

    Oyster (Saccostrea commercialis) biomonitoring, assessment of oyster and gastropod (Bembicium auratum) abundance, and gastropod imposex were used to measure the significance of tributyltin (TBT) contamination in an intertidal mangrove forest. We studied the bioavailable levels of TBT in oysters approximately 1 km downstream and 2 km upstream from a TBT waste disposal site. We found observable declines in the abundance of oysters and gastropods correlated with the bioavailable TBT and these findings were confirmed by mapping oyster beds. Oyster cover near the disposal site ranged from 0% to 5% while downstream and upstream populations ranged in cover from 25-50% to 5-25%, respectively. Similarly, gastropod abundances at the disposal site were only 7% of the downstream population and 17% of the upstream population. Imposex was present in 90% of female B. auratum from populations near the disposal site but this effect declined more sharply than the population level effects.

  9. An easy, rapid and inexpensive method to monitor tributyltin (TBT) toxicity in the laboratory.

    Science.gov (United States)

    Cruz, Andreia; Moreira, Rafael; Mendo, Sónia

    2014-05-01

    Tributyltin (TBT) contamination remains a major problem worldwide. Many laboratories are committed to the development of remediation methodologies that could help reduce the negative impact of this compound in the environment. Furthermore, it is important to have at hand simple methodologies for evaluating TBT toxicity in the laboratory, besides the use of complex and costly analytical instrumentation. With that purpose, a method was adapted that is based on the inhibition of growth of an indicator strain, Micrococcus luteus ATCC 9341, under TBT. Different types of matrices, of TBT concentrations and sample treatments were tested. The results herein reported show that the bioassay method can be applied for both aqueous and soil samples and also for a high range of TBT concentrations (at least up to 500 μmol/L). Besides being cheap and easy to perform, it can be performed in any laboratory. Additionally, one possible application of the method to monitor TBT degradation is presented as an example.

  10. Obesogens beyond Vertebrates: Lipid Perturbation by Tributyltin in the Crustacean Daphnia magna

    Science.gov (United States)

    Jordão, Rita; Casas, Josefina; Fabrias, Gemma; Campos, Bruno; Piña, Benjamín; Lemos, Marco F.L.; Soares, Amadeu M.V.M.; Tauler, Romà

    2015-01-01

    Background The analysis of obesogenic effects in invertebrates is limited by our poor knowledge of the regulatory pathways of lipid metabolism. Recent data from the crustacean Daphnia magna points to three signaling hormonal pathways related to the molting and reproductive cycles [retinoic X receptor (RXR), juvenile hormone (JH), and ecdysone] as putative targets for exogenous obesogens. Objective The present study addresses the disruptive effects of the model obesogen tributyltin (TBT) on the lipid homeostasis in Daphnia during the molting and reproductive cycle, its genetic control, and health consequences of its disruption. Methods D. magna individuals were exposed to low and high levels of TBT. Reproductive effects were assessed by Life History analysis methods. Quantitative and qualitative changes in lipid droplets during molting and the reproductive cycle were studied using Nile red staining. Lipid composition and dynamics were analyzed by ultra-performance liquid chromatography coupled to a time-of-flight mass spectrometer. Relative abundances of mRNA from different genes related to RXR, ecdysone, and JH signaling pathways were studied by qRT-PCR. Results and Conclusions TBT disrupted the dynamics of neutral lipids, impairing the transfer of triacylglycerols to eggs and hence promoting their accumulation in adult individuals. TBT’s disruptive effects translated into a lower fitness for offspring and adults. Co-regulation of gene transcripts suggests that TBT activates the ecdysone, JH, and RXR receptor signaling pathways, presumably through the already proposed interaction with RXR. These findings indicate the presence of obesogenic effects in a nonvertebrate species. Citation Jordão R, Casas J, Fabrias G, Campos B, Piña B, Lemos MF, Soares AM, Tauler R, Barata C. 2015. Obesogens beyond vertebrates: lipid perturbation by tributyltin in the crustacean Daphnia magna. Environ Health Perspect 123:813–819; http://dx.doi.org/10.1289/ehp.1409163 PMID

  11. Effects of Tributyltin Chloride on Cybrids with or without an ATP Synthase Pathologic Mutation.

    Science.gov (United States)

    López-Gallardo, Ester; Llobet, Laura; Emperador, Sonia; Montoya, Julio; Ruiz-Pesini, Eduardo

    2016-09-01

    The oxidative phosphorylation system (OXPHOS) includes nuclear chromosome (nDNA)- and mitochondrial DNA (mtDNA)-encoded polypeptides. Many rare OXPHOS disorders, such as striatal necrosis syndromes, are caused by genetic mutations. Despite important advances in sequencing procedures, causative mutations remain undetected in some patients. It is possible that etiologic factors, such as environmental toxins, are the cause of these cases. Indeed, the inhibition of a particular enzyme by a poison could imitate the biochemical effects of pathological mutations in that enzyme. Moreover, environmental factors can modify the penetrance or expressivity of pathological mutations. We studied the interaction between mitochondrially encoded ATP synthase 6 (p.MT-ATP6) subunit and an environmental exposure that may contribute phenotypic differences between healthy individuals and patients suffering from striatal necrosis syndromes or other mitochondriopathies. We analyzed the effects of the ATP synthase inhibitor tributyltin chloride (TBTC), a widely distributed environmental factor that contaminates human food and water, on transmitochondrial cell lines with or without an ATP synthase mutation that causes striatal necrosis syndrome. Doses were selected based on TBTC concentrations previously reported in human whole blood samples. TBTC modified the phenotypic effects caused by a pathological mtDNA mutation. Interestingly, wild-type cells treated with this xenobiotic showed similar bioenergetics when compared with the untreated mutated cells. In addition to the known genetic causes, our findings suggest that environmental exposure to TBTC might contribute to the etiology of striatal necrosis syndromes. López-Gallardo E, Llobet L, Emperador S, Montoya J, Ruiz-Pesini E. 2016. Effects of tributyltin chloride on cybrids with or without an ATP synthase pathologic mutation. Environ Health Perspect 124:1399-1405; http://dx.doi.org/10.1289/EHP182.

  12. Oxygen intrusion into anoxic fjords leads to increased methylmercury availability

    Science.gov (United States)

    Veiteberg Braaten, Hans Fredrik; Pakhomova, Svetlana; Yakushev, Evgeniy

    2013-04-01

    Mercury (Hg) appears in the oxic surface waters of the oceans at low levels (sub ng/L). Because inorganic Hg can be methylated into the toxic and bioaccumulative specie methylmercury (MeHg) levels can be high at the top of the marine food chain. Even though marine sea food is considered the main risk driver for MeHg exposure to people most research up to date has focused on Hg methylation processes in freshwater systems. This study identifies the mechanisms driving formation of MeHg during oxygen depletion in fjords, and shows how MeHg is made available in the surface water during oxygen intrusion. Studies of the biogeochemical structure in the water column of the Norwegian fjord Hunnbunn were performed in 2009, 2011 and 2012. In autumn of 2011 mixing flushing events were observed and lead to both positive and negative effects on the ecosystem state in the fjord. The oxygenated water intrusions lead to a decrease of the deep layer concentrations of hydrogen sulfide (H2S), ammonia and phosphate. On the other hand the intrusion also raised the H2S boundary from 8 m to a shallower depth of just 4 m. Following the intrusion was also observed an increase at shallower depths of nutrients combined with a decrease of pH. Before flushing events were observed concentrations of total Hg (TotHg) increased from 1.3 - 1.7 ng/L in the surface layer of the fjord to concentrations ranging from 5.2 ng/L to 6.4 ng/L in the anoxic zone. MeHg increased regularly from 0.04 ng/L in the surface water to a maximum concentration of 5.2 ng/L in the deeper layers. This corresponds to an amount of TotHg present as MeHg ranging from 2.1 % to 99 %. The higher concentrations of MeHg in the deeper layer corresponds to an area where no oxygen is present and concentrations of H2S exceeds 500 µM, suggesting a production of MeHg in the anoxic area as a result of sulphate reducing bacteria activity. After flushing the concentrations of TotHg showed a similar pattern ranging from 0.6 ng/L in the

  13. Reaction Mechanisms of the Atomic Layer Deposition of Tin Oxide Thin Films Using Tributyltin Ethoxide and Ozone.

    Science.gov (United States)

    Nanayakkara, Charith E; Liu, Guo; Vega, Abraham; Dezelah, Charles L; Kanjolia, Ravindra K; Chabal, Yves J

    2017-06-20

    Uniform and conformal deposition of tin oxide thin films is important for several applications in electronics, gas sensing, and transparent conducting electrodes. Thermal atomic layer deposition (ALD) is often best suited for these applications, but its implementation requires a mechanistic understanding of the initial nucleation and subsequent ALD processes. To this end, in situ FTIR and ex situ XPS have been used to explore the ALD of tin oxide films using tributyltin ethoxide and ozone on an OH-terminated, SiO 2 -passivated Si(111) substrate. Direct chemisorption of tributyltin ethoxide on surface OH groups and clear evidence that subsequent ligand exchange are obtained, providing mechanistic insight. Upon ozone pulse, the butyl groups react with ozone, forming surface carbonate and formate. The subsequent tributyltin ethoxide pulse removes the carbonate and formate features with the appearance of the bands for CH stretching and bending modes of the precursor butyl ligands. This ligand-exchange behavior is repeated for subsequent cycles, as is characteristic of ALD processes, and is clearly observed for deposition temperatures of 200 and 300 °C. On the basis of the in situ vibrational data, a reaction mechanism for the ALD process of tributyltin ethoxide and ozone is presented, whereby ligands are fully eliminated. Complementary ex situ XPS depth profiles confirm that the bulk of the films is carbon-free, that is, formate and carbonate are not incorporated into the film during the deposition process, and that good-quality SnO x films are produced. Furthermore, the process was scaled up in a cross-flow reactor at 225 °C, which allowed the determination of the growth rate (0.62 Å/cycle) and confirmed a self-limiting ALD growth at 225 and 268 °C. An analysis of the temperature-dependence data reveals that growth rate increases linearly between 200 and 300 °C.

  14. Effects of tributyltin chloride(TBTCl) on seroid hormone and seroidogenic enzymes in Sprague-Dawley male rat

    Energy Technology Data Exchange (ETDEWEB)

    Kang, T.S.; Lee, S.J.; Shin, J.H.; Kim, T.S.; Moon, H.J.; Ki, H.Y.; Bae, H.; Han, S.Y. [Endocrine Toxicology Div., National Inst. of Toxicological Research, Korea FDA, Seoul (Korea); Dong, M.S. [Korea Univ., Seoul (Korea); Yoon, Y.D. [Hanyang Univ., Seoul (Korea)

    2004-09-15

    Tributyltin (TBT), organotin compound is used a wood preservative, a stabilizer of poly-vinyl chloride (PVC), a bactericide, a vermicide, and antifouling agent in maritime paint. TBTCl has been known to bioaccumulate through the food chain and induce imposex in female gastropods. Testosterone was synthesized from cholesterol in Leydig cell. In male rat testes, cholesterol in in the inner membrane of mitochondria is converted to prognenolone by cytochrome P450 side-chain cleavage (P450scc), and prognenolone is consequently converted to progesterone by 3{beta}-hydroxysteroid dehydrogenase (3{beta}a-HSD). Progesterone is converted to testosterone by cytochrome P450 17{alpha}-hydroxylase/C17-20 lyase (P450c17), and 17{beta}-hydroxysteroid dehydrogenase (17{beta}-HSD). Testosterone is converted to estradiol by P450 aromatase. Some studies have been reported that steroidogenic enzyme and steroid hormone were affected by TBT. In a two-generation study of tributyltin chloride, serum estradiol was decreased in F1 and F2 male rats. But serum concentration of testosterone and luteinizing hormone (LH) were not changed in F1 and F2 male rats. When pregnant rats were orally administrated by TBTCl, serum progesterone was decreased and serum estradiol was increased in female litters. Also litters were affected on development of reproductive organs and sexual of differentiation by TBTCl.3 Tributyltin increased serum progesterone in granulosa cells, but serum testosterone and estradiol were diminished.4 TBT has been known that it repressed P450 aromatase activity. In this study, we investigated effect of tributyltin chloride (TBTCl) on the mRNA expression of steroidogenic enzymes and steroid hormone in male rat.

  15. Alteration of General Behavior of Male Medaka,oryzias latipes,Exposed to Tributyltin and /or Polychlorinated Biphenyls

    OpenAIRE

    Nakayama, Kei; Oshima, Yuji; Hiramatsu, Kazuaki; Honjo, Tsuneo

    2004-01-01

    We examined the general behavior of male Japanese medaka, Oryzias latipes, after exposed to tributyltin (TBT), polychlorinated biphenyls (PCBs), or a mixture of these chamicals at a concentration of 1μg/g body weight daily for 3 weeks. We analyzed swimming velocity as an indicator of acute toxicity and counted the frequencies of straight swimming and swimming in circles. We also calclated the entropy of the positions of the fish within the experimental chamber. Neither TBT nor PCBs nor their ...

  16. Stability of inorganic mercury and methylmercury on yeast-silica gel microcolumns: field sampling capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Corona, M. [Universidad Complutense de Madrid (Spain). Dept. de Quimica Analitica

    2000-11-01

    The stability of methylmercury and inorganic mercury retained on yeast-silica gel microcolumns was established and compared with the stability of these species in solution. Yeast-silica gel columns with the retained analytes were stored for two months at three different temperatures: -20 C, 4 C and room temperature. At regular time intervals, both mercury species were eluted and quantified by cold vapor atomic absorption spectrometry (CVAAS). Methylmercury was found stable in the columns over the two-month period at the three different temperatures tested while the concentration of inorganic mercury decreased after one week's storage even at -20 C. These results are of great interest since the use of these microcolumns allows the preconcentration and storage of mercury species until analysis, thus saving laboratory space and avoiding the problems associated with maintaining species integrity in aqueous solution. (orig.)

  17. Sensitivity of continuous performance test (CPT) at age 14years to developmental methylmercury exposure

    DEFF Research Database (Denmark)

    Julvez, Jordi; Debes, Frodi; Weihe, Pal

    2010-01-01

    Hit Reaction Time latencies (HRT) in the Continuous Performance Test (CPT) measure the speed of visual information processing. The latencies may involve different neuropsychological functions depending on the time from test initiation, i.e., first orientation, learning and habituation, then cogni......Hit Reaction Time latencies (HRT) in the Continuous Performance Test (CPT) measure the speed of visual information processing. The latencies may involve different neuropsychological functions depending on the time from test initiation, i.e., first orientation, learning and habituation......, then cognitive processing and focused attention, and finally sustained attention as the dominant demand. Prenatal methylmercury exposure is associated with increased reaction time (RT) latencies. We therefore examined the association of methylmercury exposure with the average HRT at age 14years at three...

  18. Cognitive deficits at age 22 years associated with prenatal exposure to methylmercury

    DEFF Research Database (Denmark)

    Debes, Frodi; Weihe, Pál; Grandjean, Philippe

    2016-01-01

    methylmercury exposure was assessed in terms of the mercury concentration in cord blood and maternal hair. Clinical examinations of 847 cohort members at age 22 years were carried out in 2008-2009 using a panel of neuropsychological tests that reflected major functional domains. Subjects with neurological...... and psychiatric diagnoses were excluded from the data analysis, thus leaving 814 subjects. Multiple regression analysis included covariates previously identified for adjustment. Deficits in Boston Naming Test (BNT) and other tests of verbal performance were significantly associated with the cord-blood mercury...... to about 2.2 IQ points at a 10-fold increased prenatal methylmercury exposure. Thus, although the cognitive deficits observed were smaller than at examinations at younger ages, maternal diets with contaminated seafood were associated with adverse effects in this birth cohort at age 22 years. The deficits...

  19. Distribution of tributyltin in surface sediments from transitional marine-lagoon system of the south-eastern Baltic Sea, Lithuania.

    Science.gov (United States)

    Suzdalev, Sergej; Gulbinskas, Saulius; Blažauskas, Nerijus

    2015-02-01

    The current research paper presents the results of contamination by tributyltin (TBT) compounds in Klaipėda Port, which is situated in a unique marine-lagoon water interaction zone. One hundred fifty-four surface sediment samples have been taken along the whole transition path from lagoon to the sea and analysed in order to quantify the contamination rate in specific environment of high anthropogenic pressure. The detected TBT concentrations ranged from 1 to 5,200 ng Sn g(-1) of dry weight of sediment. The back-trace of horizontal distribution of TBT-contaminated sediments show obvious increase of tributyltin concentrations closer to port areas dealing with ship repair and places of dry-docking facilities. This is a clear indication that those activities are the main source of contamination in the study area. The estimated correlation of TBT concentration in sediments with total organic carbon and the amount of fine fraction (tributyltin is related to potential contamination source areas (ship repairing, dockyards) due to direct input of hazardous substances into the water.

  20. 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

  1. Concentrations of methylmercury in invertebrates from wetlands of the Prairie Pothole Region of North America

    International Nuclear Information System (INIS)

    Bates, Lara M.; Hall, Britt D.

    2012-01-01

    Prairie wetlands may be important sites of mercury (Hg) methylation resulting in elevated methylmercury (MeHg) concentrations in water, sediments and biota. Invertebrates are an important food resource and may act as an indicator of MeHg exposure to higher organisms. In 2007–2008, invertebrates were collected from wetland ponds in central Saskatchewan, categorized into functional feeding groups (FFGs) and analyzed for total Hg (THg) and MeHg. Methylmercury and THg concentrations in four FFGs ranged from 0.2–393.5 ng·g −1 and 9.7–507.1 ng·g −1 , respectively. Methylmercury concentrations generally increased from gastropods with significantly lower average MeHg concentrations compared to other invertebrate taxa. Surrounding land use (agricultural, grassland and organic agricultural) may influence MeHg concentrations in invertebrates, with invertebrate MeHg concentrations being higher from organic ponds (457.5 ± 156.7 ng·g −1 ) compared to those from grassland ponds (74.8 ± 14.6 ng·g −1 ) and ponds on agricultural lands (32.8 ± 6.2 ng·g −1 ). - Highlights: ► MeHg concentrations ranged from 0.2 to 393.5 ng·g −1 and generally increased with trophic level. ► Gastropods had significantly lower average MeHg concentrations compared to other invertebrates. ► Surrounding land use may influence MeHg concentrations in invertebrates. ► MeHg concentrations were higher in organic ponds compared to grassland and agricultural ponds. - Methylmercury concentrations in aquatic invertebrates in wetlands of the Great Plains of North America may differ depending on the land use of adjacent farmland.

  2. Methylmercury dynamics at the upland-peatland interface: Topographic and hydrogeochemical controls

    Science.gov (United States)

    Carl P. J. Mitchell; Brian A. Branfireun; Randall K. Kolka

    2009-01-01

    Peatlands are important environments for the transformation of atmospherically deposited inorganic mercury into the bioaccumulative form, methylmercury (MeHg), which may accumulate in downstream aquatic biota, particularly in fish. In recent research, it was suggested that MeHg production and/or accumulation ‘‘hot spots’’ at the upland-peatland interface were the...

  3. Species difference between rat and hamster in tissue accumulation of mercury after administration of methylmercury

    International Nuclear Information System (INIS)

    Omata, Saburo; Kasama, Hidetaka; Hasegawa, Hiroshi; Hasegawa, Kazuhiro; Sugano, Hiroshi; Ozaki, Kunio

    1986-01-01

    The accumulation of mercury in tissues of the rat and hamster was determined after the administration of a single dose of 203 Hg-methylmercury chloride (10 mg/kg body weight). (1) On day 2, the mercury contents of hamster tissues were higher than those of rat tissues, except for red blood cells, in which the mercury content was about 6-fold higher in the rat than in the hamster. (2) After that time, the mercury content of hamster tissues decreased rather steeply and on day 16 it had reached 14-25% in nervous tissues and 7-15% in other tissues, of the levels on day 2. (3) In the rat, on the other hand, the mercury content of nervous tissues on day 16 was higher than that on day 2 (106-220%), except for dorsal roots and dorsal root ganglia, which showed slight decreases (75-94% of the levels on day 2). In non-neural tissues, the decreases up to day 16 were also small (71-92% of the levels on day 2). (4) Thus, both the uptake and elimination of mercury seem to be more rapid in the tissues of hamster compared with those of the rat. Similar trends of mercury accumulation and elimination were observed when animals received multiple injections of methylmercury that induced acute methylmercury intoxication. (5) Significant biotransmormation of the injected methylmercury to inorganic mercury was detected in the liver, kidney and spleen of both animal species. Although the percentages of inorganic mercury in these tissues wer not so different between the two species on day 2, they became exceedingly high in the tissues of hamster at the later stage, except in the kidney cytosol, in which the values were close in both animal species between day 2 and day 16. (orig.)

  4. Mercury and methylmercury intake estimation due to seafood products for the Catalonian population (Spain)

    OpenAIRE

    2009-01-01

    Abstract This study estimates mercury and methylmercury levels in fish and fishery products commercialized in the city of Barcelona from 2001 to 2007. Combining food levels data with the consumption data of 2158 people (as the median of two 24-hour-recall), the total Mercury intake of the Catalonian population was calculated. Mercury was detected in 32,8% of analyses samples. The general population average weekly intake of total mercury in Catalonian population was 0.783 ?g/k...

  5. Alternate wetting and drying decreases methylmercury in flooded rice (Oryza sativa) systems

    Science.gov (United States)

    Tanner, K. Christy; Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark C.; Fleck, Jacob; Linquist, Bruce A.

    2018-01-01

    In flooded soils, including those found in rice (Oryza sativa L.) fields, microbes convert inorganic Hg to more toxic methylmercury (MeHg). Methylmercury is accumulated in rice grain, potentially affecting health. Methylmercury in rice field surface water can bioaccumulate in wildlife. We evaluated how introducing aerobic periods into an otherwise continuously flooded rice growing season affects MeHg dynamics. Conventional continuously flooded (CF) rice field water management was compared with alternate wetting and drying, where irrigation was stopped twice during the growing season, allowing soil to dry to 35% volumetric moisture content, at which point plots were reflooded (AWD-35). Methylmercury studies began at harvest in Year 3 and throughout Year 4 of a 4-yr replicated field experiment. Bulk soil, water, and plant samples were analyzed for MeHg and total Hg (THg), and iron (Fe) speciation was measured in soil samples. Rice grain yield over 4 yr did not differ between treatments. Soil chemistry responded quickly to AWD-35 dry-downs, showing significant oxidation of Fe(II) accompanied by a significant reduction of MeHg concentration (76% reduction at harvest) compared with CF. Surface water MeHg decreased by 68 and 39% in the growing and fallow seasons, respectively, suggesting that the effects of AWD-35 management can last through to the fallow season. The AWD-35 treatment reduced rice grain MeHg and THg by 60 and 32%, respectively. These results suggest that the more aerobic conditions caused by AWD-35 limited the activity of Hg(II)-methylating microbes and may be an effective way to reduce MeHg concentrations in rice ecosystems.

  6. Model description of trophodynamic behavior of methylmercury in a marine aquatic system

    International Nuclear Information System (INIS)

    Tong Yindong; Zhang Wei; Hu Xindi; Ou Langbo; Hu Dan; Yang Tianjun; Wei Wen; Wang Xuejun

    2012-01-01

    A marine food web in Bohai Bay, China, was selected to study methylmercury (MeHg) bioaccumulation, and an aquivalence-based mass balance model was established to explore the possibility of predicting the MeHg concentrations and quantifying MeHg bioaccumulation in the food web. Results showed that both total mercury (THg) and MeHg were biomagnified in the food web. The calculated MeHg concentrations in the selected species agreed well with the measured values, which shows the model could be a useful tool in MeHg concentration prediction in food web. Model outputs also showed that metabolism and growth dilution could be the dominant mechanisms for the reduction of MeHg levels in aquatic organisms. With the increase of trophic level, the contribution of food as a MeHg source for organism is increasing, and MeHg from prey was the dominant source. - Highlights: ► We model the bioaccumulation of methylmercury in a marine aquatic food web. ► Aquivalence-based mass balance model could quantify MeHg trophic transfer. ► Metabolism and growth dilution are dominant mechanisms of MeHg reduction in organisms. ► With increase of trophic levels, contribution of food as MeHg source is increasing. - Aquivalence-based mass balance model was established to study methylmercury bioaccumulation in a marine food web.

  7. Extraction of methylmercury from tissue and plant samples by acid leaching

    Energy Technology Data Exchange (ETDEWEB)

    Hintelmann, Holger; Nguyen, Hong T. [Trent University, Chemistry Department, Peterborough, ON (Canada)

    2005-01-01

    A simple and efficient extraction method based on acidic leaching has been developed for measurement of methylmercury (MeHg) in benthic organisms and plant material. Methylmercury was measured by speciated isotope-dilution mass spectrometry (SIDMS), using gas chromatography interfaced with inductively coupled plasma mass spectrometry (GC-ICP-MS). Reagent concentration and digestion temperature were optimized for several alkaline and acidic extractants. Recovery was evaluated by addition of MeHg enriched with CH{sub 3}{sup 201}Hg{sup +}. Certified reference materials (CRM) were used to evaluate the efficiency of the procedure. The final digestion method used 5 mL of 4 mol L{sup -1} HNO{sub 3} at 55 C to leach MeHg from tissue and plant material. The digest was further processed by aqueous phase ethylation, without interference with the ethylation step, resulting in 96{+-}7% recovery of CH{sub 3}{sup 201}Hg{sup +} from oyster tissue and 93{+-}7% from pine needles. Methylmercury was stable in this solution for at least 1 week and measured concentrations of MeHg in CRM were statistically not different from certified values. The method was applied to real samples of benthic invertebrates and inter-laboratory comparisons were conducted using lyophilized zooplankton, chironomidae, and notonectidae samples. (orig.)

  8. Methylmercury determination in fish and seafood products and estimated daily intake for the Spanish population.

    Science.gov (United States)

    Sahuquillo, I; Lagarda, M J; Silvestre, M D; Farré, R

    2007-08-01

    The mercury content of 25 samples of fish and seafood products most frequently consumed in Spain was determined. A simple method comprising cold vapour and atomic absorption spectrometry was used to determine separately inorganic and organic mercury. In all samples inorganic mercury content was below 50 microg kg(-1). There was wide variability, among not only the mercury levels of different fish species, but also for different samples of the same species - with the methylmercury content ranging from below 54 to 662 microg kg(-1). The highest mean methylmercury content was found in fresh tuna. Based on an average total fish consumption of 363 g/person week(-1), the methylmercury intake was estimated to be 46.2 microg/person week(-1). Therefore, the mercury intake of Spanish people with a body weight Food Additives (JECFA) provisional tolerable weekly intake (PTWI) of 1.6 microg kg(-1) body weight, but exceeds the US National Research Council (NRC) limit of 0.7 microg kg(-1) body weight week(-1) based on a benchmark dose.

  9. Speciation of methylmercury and ethylmercury by gas chromatography cold vapor atomic fluresence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Boggess, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-28

    Existing models and simulants of tank disposition media at SRS have presumed the presence of high concentrations of inorganic mercury. However, recent quarterly tank analyses show that mercury is present as organomercurial species at concentrations that may present challenges to remediation and disposition and may exceed the Saltstone Waste Acceptance Criteria (WAC). To-date, methylmercury analysis for Savannah River Remediation (SRR) has been performed off-site by Eurofins Scientific (Lancaster, PA). A series of optimization and validation experiments has been performed at SRNL, which has resulted in the development of on-site organomercury speciation capabilities using purge and trap gas chromatography coupled with thermal desorption cold vapor atomic fluorescence spectroscopy (P&T GC/CVAFS). Speciation has been achieved for methylmercury, with a method reporting limit (MRL) values of 1.42 pg for methylmercury. Results obtained by SRNL from the analysis of past quarterly samples from tanks 21, 40, and 50 have demonstrated statistically indistinguishable concentration values compared with the concentration data obtained from Eurofins, while the data from SRNL has demonstrated significantly improved precision and processing time.

  10. Dietary Mercury Exposure Resulted in Behavioral Differences in Mice Contaminated with Fish-Associated Methylmercury Compared to Methylmercury Chloride Added to Diet

    Directory of Open Access Journals (Sweden)

    Jean-Paul Bourdineaud

    2012-01-01

    Full Text Available Methylmercury (MeHg is a potent neurotoxin, and humans are mainly exposed to this pollutant through fish consumption. However, in classical toxicological studies, pure methylmercury chloride (MeHgCl is injected, given to drink or incorporated within feed assuming that its effects are identical to those of MeHg naturally associated to fish. In the present study, we wanted to address the question whether a diet containing MeHg associated to fish could result in observable adverse effects in mice as compared to a diet containing the same concentration of MeHg added pure to the diet and whether beneficial nutriments from fish were able to counterbalance the deleterious effects of fish-associated mercury, if any. After two months of feeding, the fish-containing diet resulted in significant observable effects as compared to the control and MeHg-containing diets, encompassing altered behavioral performances as monitored in a Y-shaped maze and an open field, and an increased dopamine metabolic turnover in hippocampus, despite the fact that the fish-containing diet was enriched in polyunsaturated fatty acids and selenium compared to the fish-devoid diets.

  11. Insights from mercury stable isotopes into factors affecting the internal body burden of methylmercury in frequent fish consumers

    Directory of Open Access Journals (Sweden)

    Miling Li

    2016-05-01

    Full Text Available Abstract Methylmercury (MeHg exposure can cause adverse health effects in children and adults and is predominantly from seafood consumption in the United States (U.S.. Here we examine evidence for differences in MeHg uptake and metabolism in U.S. individuals who consume three or more fish meals per week. We hypothesized based on prior research that some individuals have enhanced capacity to demethylate ingested MeHg and this will be reflected by a greater than typically observed δ202Hg offset in their hair relative to consumed fish (∼2 ‰. We used self-reported seafood intake data to identify individuals with hair Hg concentrations that agree extremely well with reported ingestion and those that do not. Approximately one-third of individuals in our survey population had hair Hg levels below the lower bound of probabilistic exposure modeling based on dietary intake data. The Δ199Hg values measured in the hair of a subset of individuals with the highest and lowest discrepancies between modeled and measured exposures are consistent with self-reported fish intake, validating the reliability of their dietary recall information. The δ202Hg offset between fish and human hair is similar for low- and high-discrepancy individuals, suggesting enhanced in vivo demethylation does not explain some individuals with hair Hg levels equivalent to non-fish consumers (0.10 ug/g. Using the probabilistic exposure model, we find dietary MeHg absorption efficiencies required to explain hair Hg levels in these high-discrepancy individuals are on average lower than 14% (range: 1%–72%. Exposure modeling for MeHg typically assumes a range of 91–97% and our results emphasize much greater inter-individual variability in this value.

  12. A Methylmercury Prediction Too For Surface Waters Across The Contiguous United States (Invited)

    Science.gov (United States)

    Krabbenhoft, D. P.; Booth, N.; Lutz, M.; Fienen, M. N.; Saltman, T.

    2009-12-01

    About 20 years ago, researchers at a few locations across the globe discovered high levels of mercury in fish from remote settings lacking any obvious mercury source. We now know that for most locations atmospheric deposition is the dominant mercury source, and that mercury methylation is the key process that translates low mercury loading rates into relatively high levels in top predators of aquatic food webs. Presently, almost all US states have advisories for elevated levels of mercury in sport fish, and as a result there is considerable public awareness and concern for this nearly ubiquitous contaminant issue. In some states, “statewide” advisories have been issued because elevated fish mercury levels are so common, or the state has no effective way to monitor thousands of lakes, reservoirs, wetlands, and streams. As such, resource managers and public health officials have limited options for informing the public on of where elevated mercury concentrations in sport fish are more likely to occur than others. This project provides, for the first time, a national map of predicted (modeled) methylmercury concentrations in surface waters, which is the most toxic and bioaccumulative form of mercury in the environment. The map is the result of over two decades of research that resulted in the formulation of conceptual models of the mercury methylation process, which is strongly governed by environmental conditions - specifically hydrologic landscapes and water quality. The resulting predictive map shows clear regional trends in the distribution of methylmercury concentrations in surface waters. East of the Mississippi, the Gulf and southeastern Atlantic coast, the northeast, the lower Mississippi valley, and Great Lakes area are predicted to have generally higher environmental methylmercury levels. Higher-elevation, well-drained areas of Appalachia are predicted to have relatively lower methylmercury abundance. Other than the prairie pothole region, in the western

  13. 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.

  14. Isolation and characterization of bacteria from mercury contaminated sites in Rio Grande do Sul, Brazil, and assessment of methylmercury removal capability of a Pseudomonas putida V1 strain.

    Science.gov (United States)

    Cabral, Lucélia; Giovanella, Patrícia; Gianello, Clésio; Bento, Fátima Menezes; Andreazza, Robson; Camargo, Flávio Anastácio Oliveira

    2013-06-01

    Methylmercury (MeHg) is one of the most dangerous heavy metal for living organisms that may be found in environment. Given the crescent industrialization of Brazil and considering that mercury is a residue of several industrial processes, there is an increasing need to encounter and develop remediation approaches of mercury contaminated sites. The aim of this study was to isolate and characterize methylmercury resistant bacteria from soils and sludge sewage from Rio Grande do Sul, Brazil. Sixteen bacteria were isolated from these contaminated sites and some isolates were highly resistant to methylmercury (>8.7 μM). All the isolates were identified by 16S rDNA. Pseudomonas putida V1 was able to volatilize approximately 90 % of methylmercury added to growth media and to resist to copper, lead, nickel, chromate, zinc, cobalt, manganese and barium. In the presence of high concentrations of methylmercury (12 μM), cell growth was limited, but P. putida V1 was still able to remove up to 29 % of this compound from culture medium. This bacterium removed an average of 77 % of methylmercury from culture medium with pH in the range 4.0-6.0. In addition, methylmercury was efficiently removed (>80 %) in temperature of 21-25 °C. Polymerase chain reactions indicated the presence of merA but not merB in P. putida V1. The growth and ability of P. putida V1 to remove methylmercury in a wide range of pH (4.0 and 8.0) and temperature (10-35 °C), its tolerance to other heavy metals and ability to grow in the presence of up to 11.5 μM of methylmercury, suggest this strain as a new potential resource for degrading methylmercury contaminated sites.

  15. Determination of a site-specific reference dose for methylmercury for fish-eating populations.

    Science.gov (United States)

    Shipp, A M; Gentry, P R; Lawrence, G; Van Landingham, C; Covington, T; Clewell, H J; Gribben, K; Crump, K

    2000-11-01

    Environmental risk-management decisions in the U.S. involving potential exposures to methylmercury currently use a reference dose (RfD) developed by the U.S. Environmental Protection Agency (USEPA). This RfD is based on retrospective studies of an acute poisoning incident in Iraq in which grain contaminated with a methylmercury fungicide was inadvertently used in the baking of bread. The exposures, which were relatively high but lasted only a few months, were associated with neurological effects in both adults (primarily paresthesia) and infants (late walking, late talking, etc.). It is generally believed that the developing fetus represents a particularly sensitive subpopulation for the neurological effects of methylmercury. The USEPA derived an RfD of 0.1 microg/kg/day based on benchmark dose (BMD) modeling of the combined neurological endpoints reported for children exposed in utero. This RfD included an uncertainty factor of 10 to consider human pharmacokinetic variability and database limitations (lack of data on multigeneration effects or possible long-term sequelae of perinatal exposure). Alcoa signed an Administrative Order of Consent for the conduct of a remedial investigation/feasibility study (RI/FS) at their Point Comfort Operations and the adjacent Lavaca Bay in Texas to address the effects of historical discharges of mercury-containing wastewater. In cooperation with the Texas Natural Resource Conservation Commission and USEPA Region VI, Alcoa conducted a baseline risk assessment to assess potential risk to human health and the environment. As a part of this assessment. Alcoa pursued the development of a site-specific RfD for methylmercury to specifically address the potential human health effects associated with the ingestion of contaminated finfish and shellfish from Lavaca Bay. Application of the published USEPA RfD to this site is problematic; while the study underlying the RfD represented acute exposure to relatively high concentrations of

  16. Aerobic Fitness and Neurocognitive Function Scores in Young Faroese Adults and Potential Modification by Prenatal Methylmercury Exposure

    DEFF Research Database (Denmark)

    Oulhote, Youssef; Debes, Frodi; Vestergaard, Sonja

    2017-01-01

    deviation (SD) increase in VO2Max was associated with better scores on short-term memory and cognitive processing speed by 0.21 SD (95% CI: -0.04, 0.46) and 0.28 SD (95% CI: 0.02, 0.54), respectively. In the group with lower prenatal methylmercury exposure, a 1 SD increase in VO2Max was associated...... with increased scores on cognitive processing speed by 0.45 SD (95% CI: 0.08, 0.81) and with a slightly lesser benefit in short-term memory. No such association was observed in the group with high prenatal methylmercury exposure. CONCLUSIONS: Higher aerobic capacity was associated with better performance...... in short-term memory and processing speed. However, prenatal methylmercury exposure seemed to attenuate these positive associations....

  17. 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...

  18. The association between blood pressure and whole blood methylmercury in a cross-sectional study among Inuit in Greenland

    DEFF Research Database (Denmark)

    Nielsen, Anni Brit Sternhagen; Davidsen, Michael; Bjerregaard, Peter

    2012-01-01

    to a high exposure of methylmercury. We examined the relation between whole blood mercury and blood pressure (BP) in Inuit in Greenland. METHODS: A cross-sectional population-based study among adult Inuit in Greenland was performed in 2005-2009. Information on socio-demography, lifestyle, BP, blood samples...... whole blood mercury concentrations, diastolic BP and the risk of hypertension decreased among men in the study: this may be explained by confounding by exercise or unknown factors.......BACKGROUND: The Inuit in Greenland have a high average consumption of marine species and are highly exposed to methylmercury, which in other studies has been related to hypertension. Data on the relation between methylmercury and hypertension is limited, especially in populations subjected...

  19. Tributyltin in environmental samples from the Former Derecktor Shipyard, Coddington Cove, Newport RI

    Energy Technology Data Exchange (ETDEWEB)

    Wade, Terry L.; Sweet, Stephen T.; Quinn, James G.; Cairns, Robert W.; King, John W

    2004-05-01

    Tributyltin (TBT) was detected in all 24 surface sediment (top 2 cm) samples collected from Coddington Cove, Newport, RI. TBT surface sediment concentrations ranged from 32 to 372 ng Sn/g with a mean concentration of 146 ng Sn/g. Analyses of selected core sections detected TBT in at least the top 18 cm at all 7 stations where cores were collected. No consistent TBT concentration trends with depth for these cores suggest mixing is an important process in the sediment column. In one core (station 28), TBT was found in the 76-86 cm section at a concentration of 141 ng Sn/g; thus sediments are a significant sink for TBT. However, sediment mixing processes can enhance releases of bioavailable TBT. Mussels, clams and fish from Coddington Cove contain TBT at concentrations ranging from 9.2 to 977 ng Sn/g. TBT concentrations in lobsters were below the detection limit (<6 ng Sn/g). Based on available screening criteria, TBT concentrations in Coddington Cove sediment is likely to be having an adverse effect on the biota at some locations. - TBT is likely to continue to be bioavailable for many years.

  20. Seasonal and spatial distributions of tributyltin in surface sediment of the Tolka Estuary, Dublin, Ireland

    International Nuclear Information System (INIS)

    Buggy, Conor J.; Tobin, John M.

    2006-01-01

    Aquatic pollution by tributyltin (TBT) is of concern because of its high toxicity to marine life. TBT loadings of estuarine sediments may remain elevated because of long flushing times in estuaries due to their enclosed physicality. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant pollution loading. The results of 12 months' analysis of TBT spatial and temporal distributions in this estuary are presented in this paper. Data from a total of 10 sample points are presented. The concentrations of TBT in the sediment were analysed using differential pulse polarography. Significant seasonal and spatial trends in TBT distribution were observed over the 12-month period. TBT concentrations ranged from 0.1 ppb in winter to 8.6 ppb in summer with a 1.5 ppb average. Organic matter (OM) concentrations of sediment exhibited similar seasonal trends and a positive correlation between OM and TBT distributions was observed. - TBT concentrations varied with seasons and correlated well with organic matter

  1. Tributyltin promoted hepatic steatosis in zebrafish (Danio rerio) and the molecular pathogenesis involved.

    Science.gov (United States)

    Zhang, Jiliang; Sun, Ping; Kong, Tao; Yang, Fan; Guan, Wenchao

    2016-01-01

    Endocrine disruptor effects of tributyltin (TBT) are well established in fish. However, the adverse effects on lipid metabolism are less well understood. Since the liver is the predominant site of de novo synthesis of lipids, the present study uses zebrafish (Danio rerio) to examine lipid accumulation in the livers and hepatic gene expression associated with lipid metabolism pathways. After exposure for 90 days, we found that the livers in fish exposed to TBT were yellowish in appearance and with accumulation of lipid droplet, which is consistent with the specific pathological features of steatosis. Molecular analysis revealed that TBT induced hepatic steatosis by increasing the gene expression associated with lipid transport, lipid storage, lipiogenic enzymes and lipiogenic factors in the livers. Moreover, TBT enhanced hepatic caspase-3 activity and up-regulated genes related to apoptosis and cell-death, which indicated steatotic livers of fish exposed to TBT and the subsequent liver damage were likely due to accelerated hepatocyte apoptosis or cell stress. In short, TBT can produce multiple and complex alterations in transcriptional activity of lipid metabolism and cell damage, which provides potential molecular evidence of TBT on hepatic steatosis. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Comparative toxicity of low dose tributyltin chloride on serum, liver, lung and kidney following subchronic exposure.

    Science.gov (United States)

    Mitra, Sumonto; Gera, Ruchi; Singh, Vikas; Khandelwal, Shashi

    2014-02-01

    Tributyltin (TBT) pollution is rampant worldwide and is a growing threat due to its bio-accumulative property. Isolated studies of TBT toxicity on different organs are available but consolidated information is greatly lacking. We planned this study to delineate the effect of subchronic (1 month) exposure to low dose TBT-chloride (TBTC) (1 and 5 mg/kg) in male Wistar rats. Total tin concentration was found to be significantly increased in liver, kidney and blood, and marginally in lungs. Organo-somatic indices were seen to be altered with little effect on serum biochemical markers (liver and kidney function, and general parameters). Reactive oxygen species but not lipid peroxidation content was observed to be significantly elevated both in the tissues and serum. TBTC was found to act as a hyperlipidemic agent and it also affected heme biosynthetic pathway. Hematological analysis showed that TBTC exposure resulted in minor alterations in RBC parameters. Histological studies demonstrated marked tissue damage in all the 3 organs. Calcium inhibitors (BAPTA-AM, EGTA) and antioxidants (NAC, C-PC) significantly restored TBTC induced loss in cell viability, under ex-vivo conditions. Antioxidants were evidently more efficient in comparison to the calcium inhibitors, implying major role of oxidative stress pathways in TBTC toxicity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Tributyltin induces disruption of microfilament in HL7702 cells via MAPK-mediated hyperphosphorylation of VASP.

    Science.gov (United States)

    Tu, Wei-Wei; Ji, Lin-Dan; Qian, Hai-Xia; Zhou, Mi; Zhao, Jin-Shun; Xu, Jin

    2016-11-01

    Tributyltin (TBT) has been widely used for various industrial purposes, and it has toxic effects on multiple organs and tissues. Previous studies have found that TBT could induce cytoskeletal disruption, especially of the actin filaments. However, the underlying mechanisms remain unclear. The aim of the present study was to determine whether TBT could induce microfilament disruption using HL7702 cells and then to assess for the total levels of various microfilament-associated proteins; finally, the involvement of the MAPK pathway was investigated. The results showed that after TBT treatment, F-actin began to depolymerize and lost its characteristic filamentous structure. The protein levels of Ezrin and Cofilin remained unchanged, the actin-related protein (ARP) 2/3 levels decreased slightly, and the vasodilator-stimulated phosphoprotein (VASP) decreased dramatically. However, the phosphorylation levels of VASP increased 2.5-fold, and the ratio of phosphorylated-VASP/unphosphorylated-VASP increased 31-fold. The mitogen-activated protein kinases (MAPKs) ERK and JNK were discovered to be activated. Inhibition of ERK and JNK not only largely diminished the TBT-induced hyperphosphorylation of VASP but also recovered the cellular morphology and rescued the cells from death. In summary, this study demonstrates that TBT-induced disruption of actin filaments is caused by the hyperphosphorylation of VASP through MAPK pathways. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1530-1538, 2016. © 2015 Wiley Periodicals, Inc.

  4. Tributyltin in environmental samples from the Former Derecktor Shipyard, Coddington Cove, Newport RI

    International Nuclear Information System (INIS)

    Wade, Terry L.; Sweet, Stephen T.; Quinn, James G.; Cairns, Robert W.; King, John W.

    2004-01-01

    Tributyltin (TBT) was detected in all 24 surface sediment (top 2 cm) samples collected from Coddington Cove, Newport, RI. TBT surface sediment concentrations ranged from 32 to 372 ng Sn/g with a mean concentration of 146 ng Sn/g. Analyses of selected core sections detected TBT in at least the top 18 cm at all 7 stations where cores were collected. No consistent TBT concentration trends with depth for these cores suggest mixing is an important process in the sediment column. In one core (station 28), TBT was found in the 76-86 cm section at a concentration of 141 ng Sn/g; thus sediments are a significant sink for TBT. However, sediment mixing processes can enhance releases of bioavailable TBT. Mussels, clams and fish from Coddington Cove contain TBT at concentrations ranging from 9.2 to 977 ng Sn/g. TBT concentrations in lobsters were below the detection limit (<6 ng Sn/g). Based on available screening criteria, TBT concentrations in Coddington Cove sediment is likely to be having an adverse effect on the biota at some locations. - TBT is likely to continue to be bioavailable for many years

  5. Tributyltin distribution and producing androgenic activity in water, sediment, and fish muscle.

    Science.gov (United States)

    Shue, Meei-Fang; Chen, Ting-Chien; Bellotindos, Luzvisminda M; Lu, Ming-Chun

    2014-01-01

    This study investigated the concentrations of Tributyltin (TBT) in water, sediment, and fish muscle samples taken from Kaohsiung Harbor and Kaoping River estuary, Taiwan. TBT concentrations in water and sediment samples ranged from less than 18.5 to 34.1 ng Sn L(-1) and from 2.44 to 29.7 ng Sn g(-1) weight per weight (w/w), respectively. Concentrations in the TBT-contaminated fish muscle samples ranged from 10.8 to 79.6 ng Sn g(-1) w/w. The TBT concentrations in fish muscle were higher than those in water and sediment samples. The fish muscle/water TBT bioconcentration factor (BCF) ranged from 590 to 3363 L kg(-1). Additionally, the water samples were assessed for androgenic activity with an MCF7-AR1 human breast cancer cell line. The androgenic activity ranged from 0.94 to 3.1 ng-dihydrotestosterone per litre water (ng-DHT L(-1)). Higher concentrations of TBT in water and sediment samples occurred in the dry season, but the androgenic activity had higher values in the rainy season.

  6. Chronic exposure to Tributyltin induces brain functional damage in juvenile common carp (Cyprinus carpio.

    Directory of Open Access Journals (Sweden)

    Zhi-Hua Li

    Full Text Available The aim of the present study was to investigate the effect of Tributyltin (TBT on brain function and neurotoxicity of freshwater teleost. The effects of long-term exposure to TBT on antioxidant related indices (MDA, malondialdehyde; SOD, superoxide dismutase; CAT, catalase; GR, glutathione reductase; GPx, glutathione peroxidase, Na+-K+-ATPase and neurological parameters (AChE, acetylcholinesterase; MAO, monoamine oxidase; NO, nitric oxide in the brain of common carp were evaluated. Fish were exposed to sublethal concentrations of TBT (75 ng/L, 0.75 μg/L and 7.5 μg/L for 15, 30, and 60 days. Based on the results, a low level and short-term TBT-induced stress could not induce the notable responses of the fish brain, but long-term exposure (more than 15 days to TBT could lead to obvious physiological-biochemical responses (based on the measured parameters. The results also strongly indicated that neurotoxicity of TBT to fish. Thus, the measured physiological responses in fish brain could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity.

  7. Chronic Exposure to Tributyltin Induces Brain Functional Damage in Juvenile Common Carp (Cyprinus carpio)

    Science.gov (United States)

    Li, Zhi-Hua; Li, Ping; Shi, Ze-Chao

    2015-01-01

    The aim of the present study was to investigate the effect of Tributyltin (TBT) on brain function and neurotoxicity of freshwater teleost. The effects of long-term exposure to TBT on antioxidant related indices (MDA, malondialdehyde; SOD, superoxide dismutase; CAT, catalase; GR, glutathione reductase; GPx, glutathione peroxidase), Na+-K+-ATPase and neurological parameters (AChE, acetylcholinesterase; MAO, monoamine oxidase; NO, nitric oxide) in the brain of common carp were evaluated. Fish were exposed to sublethal concentrations of TBT (75 ng/L, 0.75 μg/L and 7.5 μg/L) for 15, 30, and 60 days. Based on the results, a low level and short-term TBT-induced stress could not induce the notable responses of the fish brain, but long-term exposure (more than 15 days) to TBT could lead to obvious physiological-biochemical responses (based on the measured parameters). The results also strongly indicated that neurotoxicity of TBT to fish. Thus, the measured physiological responses in fish brain could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity. PMID:25879203

  8. Physiological Responses in Chinese Rare Minnow Larvae Following Exposure to Low-Dose Tributyltin.

    Science.gov (United States)

    Li, Ping; Li, Zhi-Hua

    2015-11-01

    In the present study, the antioxidant response and acetylcholinesterase (AChE) activity were measured in Chinese rare minnow larvae (Gobiocypris rarus) after exposure to tributyltin (TBT) (0, 100, 400 and 800 ngL(-1)) for 7 days, as well as the expression of a series of genes, including cr, aptase and prl genes involved in the ion-regulatory process and igfbp3 and gh related to growth rate. Results shows that oxidative stress was generated in fish exposed to TBT, as evidenced by elevated malondialdehyde levels and the inhibition of antioxidant parameters. The activity of acetylcholinesterase (AChE) was also inhibited in fish under higher TBT stress. Moreover, genes involved in ion regulation and growth were affected, based on the regulated transcription of the cr, atpase, gh, prl and igfbp3 genes in the treated groups. The observed effects of TBT upon antioxidant responses and altered expression of genes provides insight into the use of these molecular biomarkers in evaluating mechanisms of TBT toxicity in fish.

  9. Activation of AMP-activated protein kinase by tributyltin induces neuronal cell death

    International Nuclear Information System (INIS)

    Nakatsu, Yusuke; Kotake, Yaichiro; Hino, Atsuko; Ohta, Shigeru

    2008-01-01

    AMP-activated protein kinase (AMPK), a member of the metabolite-sensing protein kinase family, is activated by energy deficiency and is abundantly expressed in neurons. The environmental pollutant, tributyltin chloride (TBT), is a neurotoxin, and has been reported to decrease cellular ATP in some types of cells. Therefore, we investigated whether TBT activates AMPK, and whether its activation contributes to neuronal cell death, using primary cultures of cortical neurons. Cellular ATP levels were decreased 0.5 h after exposure to 500 nM TBT, and the reduction was time-dependent. It was confirmed that most neurons in our culture system express AMPK, and that TBT induced phosphorylation of AMPK. Compound C, an AMPK inhibitor, reduced the neurotoxicity of TBT, suggesting that AMPK is involved in TBT-induced cell death. Next, the downstream target of AMPK activation was investigated. Nitric oxide synthase, p38 phosphorylation and Akt dephosphorylation were not downstream of TBT-induced AMPK activation because these factors were not affected by compound C, but glutamate release was suggested to be controlled by AMPK. Our results suggest that activation of AMPK by TBT causes neuronal death through mediating glutamate release

  10. Adipogenic Effects of a Combination of the Endocrine-Disrupting Compounds Bisphenol A, Diethylhexylphthalate, and Tributyltin

    Directory of Open Access Journals (Sweden)

    Ronald Biemann

    2014-01-01

    Full Text Available Objective: The food contaminants bisphenol A (BPA, diethylhexylphthalate (DEHP, and tributyltin (TBT are potent endocrine-disrupting compounds (EDC known to interfere with adipogenesis. EDC usually act in mixtures and not as single compounds. The aim of this study was to investigate the effects of a simultaneous exposure of BPA, DEHP, and TBT on mesenchymal stem cell differentiation into adipocytes. Methods: Multipotent murine mesenchymal stem cells (C3H10T1/2 were exposed to EDC mixtures in high concentrations, i.e. MIX-high (10 µmol/l BPA, 100 µmol/l DEHP, 100 nmol/l TBT, and in environmentally relevant concentrations, i.e. MIX-low (10 nmol/l BPA, 100 nmol/l DEHP, 1 nmol/l TBT. The exposure was performed either for the entire culture time (0-12 days or at distinct stages of adipogenic differentiation. At day 12 of cell culture, the amount of adipocytes, triglyceride content (TG, and adipogenic marker gene expression were analyzed. Results: MIX-high increased the development of adipocytes and the expression of adipogenic marker genes independently of the exposure window. The total TG amount was not increased. The low-concentrated EDC mixture had no obvious impact on adipogenesis. Conclusion: In EDC mixtures, the adipogenic effect of TBT and DEHP predominates single effects of BPA. Mixture effects of EDC are not deducible from single compound experiments.

  11. Prenatal Exposure to the Environmental Obesogen Tributyltin Predisposes Multipotent Stem Cells to Become Adipocytes

    Science.gov (United States)

    Kirchner, Séverine; Kieu, Tiffany; Chow, Connie; Casey, Stephanie; Blumberg, Bruce

    2010-01-01

    The environmental obesogen hypothesis proposes that pre- and postnatal exposure to environmental chemicals contributes to adipogenesis and the development of obesity. Tributyltin (TBT) is an agonist of both retinoid X receptor (RXR) and peroxisome proliferator-activated receptor γ (PPARγ). Activation of these receptors can elevate adipose mass in adult mice exposed to the chemical in utero. Here we show that TBT sensitizes human and mouse multipotent stromal stem cells derived from white adipose tissue [adipose-derived stromal stem cells (ADSCs)] to undergo adipogenesis. In vitro exposure to TBT, or the PPARγ activator rosiglitazone increases adipogenesis, cellular lipid content, and expression of adipogenic genes. The adipogenic effects of TBT and rosiglitazone were blocked by the addition of PPARγ antagonists, suggesting that activation of PPARγ mediates the effect of both compounds on adipogenesis. ADSCs from mice exposed to TBT in utero showed increased adipogenic capacity and reduced osteogenic capacity with enhanced lipid accumulation in response to adipogenic induction. ADSCs retrieved from animals exposed to TBT in utero showed increased expression of PPARγ target genes such as the early adipogenic differentiation gene marker fatty acid-binding protein 4 and hypomethylation of the promoter/enhancer region of the fatty acid-binding protein 4 locus. Hence, TBT alters the stem cell compartment by sensitizing multipotent stromal stem cells to differentiate into adipocytes, an effect that could likely increase adipose mass over time. PMID:20160124

  12. Effect of tributyltin on antioxidant ability and immune responses of zebrafish (Danio rerio).

    Science.gov (United States)

    Zhang, Chun-Nuan; Zhang, Ji-Liang; Ren, Hong-Tao; Zhou, Bian-Hua; Wu, Qiu-Jue; Sun, Ping

    2017-04-01

    Tributyltin (TBT) is a toxic compound released into aquatic ecosystems through antifouling paints. This study was designed to examine the effects of TBT on antioxidant ability and immune responses of zebrafish (Danio rerio). Three hundred sixty healthy zebrafish were randomly grouped into four groups and exposed to different doses of TBT (0, 1, 10 and 100ngL -1 ). At the end of 8 weeks, the fish were sampled, and antioxidant capability, immune parameters and immune-related genes were assessed. The results showed that with an increase in TBT dose, the concentration of malonaldehyde in the liver was significantly increased (p<0.05), whereas the activities of total superoxide dismutase, catalase and glutathione peroxidase were significantly decreased (p<0.05) compared to the control. The activity and expression of lysozyme and the content of immunoglobulin M were significantly decreased compared to those of the fish exposed to 0ngL -1 TBT (p<0.05). However, the expression of the HSP70, HSP90, tumor necrosis factor-α(TNF-α), interleukins (IL-1β, IL-6), and nuclear factor-kappa B p65 (NF-κ B p65) genes were all enhanced with an increase in TBT dose. The results indicated that TBT induced oxidative stress and had immunotoxic effects on zebrafish. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Seasonal and spatial distributions of tributyltin in surface sediment of the Tolka Estuary, Dublin, Ireland

    Energy Technology Data Exchange (ETDEWEB)

    Buggy, Conor J. [Department of Biotechnology, Dublin City University, Glasnevin, Dublin (Ireland); Tobin, John M. [Department of Biotechnology, Dublin City University, Glasnevin, Dublin (Ireland)]. E-mail: john.tobin@dcu.ie

    2006-09-15

    Aquatic pollution by tributyltin (TBT) is of concern because of its high toxicity to marine life. TBT loadings of estuarine sediments may remain elevated because of long flushing times in estuaries due to their enclosed physicality. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant pollution loading. The results of 12 months' analysis of TBT spatial and temporal distributions in this estuary are presented in this paper. Data from a total of 10 sample points are presented. The concentrations of TBT in the sediment were analysed using differential pulse polarography. Significant seasonal and spatial trends in TBT distribution were observed over the 12-month period. TBT concentrations ranged from 0.1 ppb in winter to 8.6 ppb in summer with a 1.5 ppb average. Organic matter (OM) concentrations of sediment exhibited similar seasonal trends and a positive correlation between OM and TBT distributions was observed. - TBT concentrations varied with seasons and correlated well with organic matter.

  14. Tributyltin contributes in reducing the vascular reactivity to phenylephrine in isolated aortic rings from female rats.

    Science.gov (United States)

    Rodrigues, Samya Mere L; Ximenes, Carolina F; de Batista, Priscila R; Simões, Fabiana V; Coser, Pedro Henrique P; Sena, Gabriela C; Podratz, Priscila L; de Souza, Leticia N G; Vassallo, Dalton V; Graceli, Jones B; Stefanon, Ivanita

    2014-03-21

    Organotin compounds such as tributyltin (TBT) are used as antifouling paints by shipping companies. TBT inhibits the aromatase responsible for the transformation of testosterone into estrogen. Our hypothesis is that TBT modulates the vascular reactivity of female rats. Female Wistar rats were treated daily (Control; CONT) or TBT (100 ng/kg) for 15 days. Rings from thoracic aortas were incubated with phenylephrine (PHE, 10(-10)-10(-4) M) in the presence and absence of endothelium, and in the presence of N(G)-Nitro-L-Arginine Methyl Ester (L-NAME), tetraethylammonium (TEA) and apocynin. TBT decreased plasma levels of estrogen and the vascular response to PHE. In the TBT group, the vascular reactivity was increased in the absence of endothelium, L-NAME and TEA. The decrease in PHE reactivity during incubation with apocynin was more evident in the TBT group. The sensitivity to acetylcholine (ACh) and sodium nitroprusside (SNP) was reduced in the TBT group. TBT increased collagen, reduced α1-smooth muscle actin. Female rats treated with TBT for 15 days showed morphology alteration of the aorta and decreased their vascular reactivity, probably due to mechanisms dependent on nitric oxide (NO) bioavailability, K(+) channels and an increase in oxidative stress. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  15. Physiological and molecular responses in brain of juvenile common carp (Cyprinus carpio) following exposure to tributyltin.

    Science.gov (United States)

    Li, Zhi-Hua; Li, Ping; Shi, Ze-Chao

    2016-03-01

    Tributyltin (TBT), as antifouling paints, is widely present in aquatic environment, but little is known regarding the toxicity of TBT on fish brain. In this study, the effects of exposure to TBT on the antioxidant defense system, Na(+) -K(+) -ATPase activity, neurological enzymes activity and Hsp 70 protein level in brain of juvenile common carp (Cyprinus carpio) were studied. Fish were exposed to sublethal concentrations of TBT (5, 10 and 20 μg/L) for 7 days. Based on the results, with increasing concentrations of TBT, oxidative stress was apparent as reflected by the significant higher levels of oxidative indices, as well as the significant inhibition of all antioxidant enzymes activities. Besides, the activities of Acetylcholinesterase (AChE), Monoamine oxidases (MAO) and Na(+) -K(+) -ATPase were significantly inhibited after exposure to TBT with higher concentrations. In addition, the levels of Hsp 70 protein were evaluated under TBT stress with dose-depended manner. These results suggest that selected physiological responses in fish brain could be used as potential biomarkers for monitoring residual organotin compounds present in aquatic environment. © 2014 Wiley Periodicals, Inc.

  16. Tributyltin exposure induces gut microbiome dysbiosis with increased body weight gain and dyslipidemia in mice.

    Science.gov (United States)

    Guo, Hao; Yan, Haotian; Cheng, Dong; Wei, Xinglong; Kou, Ruirui; Si, Jiliang

    2018-05-03

    Gut microbiome dysbiosis plays a profound role in the pathogenesis of obesity and tributyltin (TBT) has been found as an environmental obesogen. However, whether TBT could disturb gut microbiome and the relationship between obesity induced by TBT exposure and alteration in gut microbiota are still unknown. In order to assess the association between them, mice were exposed to TBTCl (50 μg kg -1 ) once every three days from postnatal days (PNDs) 24 to 54. The results demonstrated that TBT exposure resulted in increased body weight gain, lager visceral fat accumulation and dyslipidemia in male mice on PND 84. Correspondingly, 16S rRNA gene sequencing revealed that TBT treatment decreased gut microbial species and perturbed the microbiome composition in mice. Furthermore, Pearson's corelation coefficient analysis showed a significantly negative correlation between the body weight and the alpha diversity of gut microbiome. These results suggested that TBT exposure could induce gut microbiome dysbiosis in mice, which might contribute to the obesity pathogenesis. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Low-Concentration Tributyltin Decreases GluR2 Expression via Nuclear Respiratory Factor-1 Inhibition.

    Science.gov (United States)

    Ishida, Keishi; Aoki, Kaori; Takishita, Tomoko; Miyara, Masatsugu; Sakamoto, Shuichiro; Sanoh, Seigo; Kimura, Tomoki; Kanda, Yasunari; Ohta, Shigeru; Kotake, Yaichiro

    2017-08-11

    Tributyltin (TBT), which has been widely used as an antifouling agent in paints, is a common environmental pollutant. Although the toxicity of high-dose TBT has been extensively reported, the effects of low concentrations of TBT are relatively less well studied. We have previously reported that low-concentration TBT decreases α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptor subunit 2 ( GluR2 ) expression in cortical neurons and enhances neuronal vulnerability to glutamate. However, the mechanism of this TBT-induced GluR2 decrease remains unknown. Therefore, we examined the effects of TBT on the activity of transcription factors that control GluR2 expression. Exposure of primary cortical neurons to 20 nM TBT for 3 h to 9 days resulted in a decrease in GluR2 mRNA expression. Moreover, TBT inhibited the DNA binding activity of nuclear respiratory factor-1 (NRF-1), a transcription factor that positively regulates the GluR2 . This result indicates that TBT inhibits the activity of NRF-1 and subsequently decreases GluR2 expression. In addition, 20 nM TBT decreased the expression of genes such as cytochrome c, cytochrome c oxidase (COX) 4, and COX 6c, which are downstream of NRF-1. Our results suggest that NRF-1 inhibition is an important molecular action of the neurotoxicity induced by low-concentration TBT.

  18. Adipogenic Effects of a Combination of the Endocrine-Disrupting Compounds Bisphenol A, Diethylhexylphthalate, and Tributyltin

    Science.gov (United States)

    Biemann, Ronald; Fischer, Bernd; Navarrete Santos, Anne

    2014-01-01

    Objective The food contaminants bisphenol A (BPA), diethylhexylphthalate (DEHP), and tributyltin (TBT) are potent endocrine-disrupting compounds (EDC) known to interfere with adipogenesis. EDC usually act in mixtures and not as single compounds. The aim of this study was to investigate the effects of a simultaneous exposure of BPA, DEHP, and TBT on mesenchymal stem cell differentiation into adipocytes. Methods Multipotent murine mesenchymal stem cells (C3H10T1/2) were exposed to EDC mixtures in high concentrations, i.e. MIX-high (10 µmol/l BPA, 100 µmol/l DEHP, 100 nmol/l TBT), and in environmentally relevant concentrations, i.e. MIX-low (10 nmol/l BPA, 100 nmol/l DEHP, 1 nmol/l TBT). The exposure was performed either for the entire culture time (0-12 days) or at distinct stages of adipogenic differentiation. At day 12 of cell culture, the amount of adipocytes, triglyceride content (TG), and adipogenic marker gene expression were analyzed. Results MIX-high increased the development of adipocytes and the expression of adipogenic marker genes independently of the exposure window. The total TG amount was not increased. The low-concentrated EDC mixture had no obvious impact on adipogenesis. Conclusion In EDC mixtures, the adipogenic effect of TBT and DEHP predominates single effects of BPA. Mixture effects of EDC are not deducible from single compound experiments. PMID:24503497

  19. Improved radioiodination of 1,2-dipalmitoyl-3-IPPA via a tributyltin intermediate

    International Nuclear Information System (INIS)

    McPherson, D.W.; Luo, H.; Kropp, J.; Knapp, F.F.

    1999-01-01

    1,2-Palmitoyl-3-[15-(4-iodophenyl)pentadecan-3-oyl]-rac-glyceroI (MIPAG) is a new agent for the clinical evaluation of pancreatic lipase activity and has demonstrated promise in preliminary clinical studies with patients affected with pancreatic insufficiency. Iodine-131-MIPAG was initially prepared via thallium-iodide displacement. Because of the need for a simple method which is amendable for the routine clinical use of MIPAG we have investigated the preparation and radioiodination of MIPAG utilizing the tributyltin precursor, 1,2-palmitoyl-3-[15-(-4-tributylstannylphenyl)pentadecan-3-oyl] -rac-glyceroI (TBT-MIPAG, 2). Compound 2 was prepared via the condensation of 1,2-palmitoyl-rac-glycerol with 15-(4-tributylstannylphenyl)pentadecanoic acid (TBT-PPA) prepared from 4-bromophenylacetylene. Electrophilic radioiodination using peracetic acid with sodium iodide-125 in ethanol at 80 deg. C for 60 min afforded I-125-MIPAG in 65.9% (±11.5%) yield and radiochemical purity of 94% (±3.0%) after C-18 Sep-Pak purification (n=6). This improved method for radioiodination utilizing TBT-MIPAG now provides radioiodinated MIPAG for routine clinical evaluation

  20. Prenatal Exposure to Tributyltin Decreases GluR2 Expression in the Mouse Brain.

    Science.gov (United States)

    Ishida, Keishi; Saiki, Takashi; Umeda, Kanae; Miyara, Masatsugu; Sanoh, Seigo; Ohta, Shigeru; Kotake, Yaichiro

    2017-01-01

    Tributyltin (TBT), a common environmental contaminant, is widely used as an antifouling agent in paint. We previously reported that exposure of primary cortical neurons to TBT in vitro decreased the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit glutamate receptor 2 (GluR2) expression and subsequently increased neuronal vulnerability to glutamate. Therefore, to identify whether GluR2 expression also decreases after TBT exposure in vivo, we evaluated the changes in GluR2 expression in the mouse brain after prenatal or postnatal exposure to 10 and 25 ppm TBT through pellet diets. Although the mean feed intake and body weight did not decrease in TBT-exposed mice compared with that in control mice, GluR2 expression in the cerebral cortex and hippocampus decreased after TBT exposure during the prenatal period. These results indicate that a decrease in neuronal GluR2 may be involved in TBT-induced neurotoxicity, especially during the fetal period.

  1. Tributyltin induces mitochondrial fission through Mfn1 degradation in human induced pluripotent stem cells.

    Science.gov (United States)

    Yamada, Shigeru; Asanagi, Miki; Hirata, Naoya; Itagaki, Hiroshi; Sekino, Yuko; Kanda, Yasunari

    2016-08-01

    Organotin compounds, such as tributyltin (TBT), are well-known endocrine disruptors. TBT is also known to cause various forms of cytotoxicity, including neurotoxicity and immunotoxicity. However, TBT toxicity has not been identified in normal stem cells. In the present study, we examined the effects of TBT on cell growth in human induced pluripotent stem cells (iPSCs). We found that exposure to nanomolar concentrations of TBT decreased intracellular ATP levels and inhibited cell viability in iPSCs. Because TBT suppressed energy production, which is a critical function of the mitochondria, we further assessed the effects of TBT on mitochondrial dynamics. Staining with MitoTracker revealed that nanomolar concentrations of TBT induced mitochondrial fragmentation. TBT also reduced the expression of mitochondrial fusion protein mitofusin 1 (Mfn1), and this effect was abolished by knockdown of the E3 ubiquitin ligase membrane-associated RING-CH 5 (MARCH5), suggesting that nanomolar concentrations of TBT could induce mitochondrial dysfunction via MARCH5-mediated Mfn1 degradation in iPSCs. Thus, mitochondrial function in normal stem cells could be used to assess cytotoxicity associated with metal exposure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Consequences of tributyltin chloride induced stress in Leydig cells: an ex-vivo approach.

    Science.gov (United States)

    Mitra, Sumonto; Srivastava, Ankit; Khanna, Smita; Khandelwal, Shashi

    2014-03-01

    Tributyltin (TBT), a member of the organotin family, is a known endocrine disruptor. It persists long in the environment and is widely used in various industrial applications. This study was planned to understand its toxic influence on Leydig cells isolated from 28 day old wistar rats. In-vitro exposure to TBT-Chloride (TBTC) (300-3000 nM) reduced cell viability (DNA fragmentation, nuclear condensation and MTT assay) and affected testosterone production. TBTC induced both apoptotic and necrotic cell death (AnnexinV/PI binding assay). Involvement of calcium (Ca(2+)), redox imbalance (ROS, GSH and TBARS) and mitochondria in TBTC toxicity was evaluated by using Ca(2+) inhibitors (BAPTA-AM, EGTA, Ruthenium Red), free radical scavengers (NAC, C-Phycocyanin) and mitochondrial permeability transition pore inhibitor (Cyclosporine A). Protein expression analysis of phosphorylated MAPKinases (ERK1/2, JNK1/2, & p38), steroidogenic proteins (3β-HSD, StAR & TSPO) and apoptotic proteins (Bax, Bcl2) illustrates the cytotoxic and anti-steroidogenic activity of TBTC. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Early cellular responses against tributyltin chloride exposure in primary cultures derived from various brain regions.

    Science.gov (United States)

    Mitra, Sumonto; Siddiqui, Waseem A; Khandelwal, Shashi

    2014-05-01

    Tributyltin (TBT) is a potent biocide and commonly used in various industrial sectors. Humans are mainly exposed through the food chain. We have previously demonstrated tin accumulation in brain following TBT-chloride (TBTC) exposure. In this study, effect of TBTC on dissociated cells from different brain regions was evaluated. Cytotoxicity assay (MTT), mode of cell death (Annexin V/PI assay), oxidative stress parameters (ROS and lipid peroxidation), reducing power of the cell (GSH), mitochondrial membrane potential (MMP) and intracellular Ca(2+) were evaluated to ascertain the effect of TBTC. Expression of glial fibrillary acidic protein (GFAP) was measured to understand the effect on astroglial cells. TBTC as low as 30 nM was found to reduce GSH levels, whereas higher doses of 300 and 3000 nM induced ROS generation and marked loss in cell viability mainly through apoptosis. Striatum showed higher susceptibility than other regions, which may have further implications on various neurological aspects. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. NAD-dependent isocitrate dehydrogenase as a novel target of tributyltin in human embryonic carcinoma cells

    Science.gov (United States)

    Yamada, Shigeru; Kotake, Yaichiro; Demizu, Yosuke; Kurihara, Masaaki; Sekino, Yuko; Kanda, Yasunari

    2014-08-01

    Tributyltin (TBT) is known to cause developmental defects as endocrine disruptive chemicals (EDCs). At nanomoler concentrations, TBT actions were mediated by genomic pathways via PPAR/RXR. However, non-genomic target of TBT has not been elucidated. To investigate non-genomic TBT targets, we performed comprehensive metabolomic analyses using human embryonic carcinoma NT2/D1 cells. We found that 100 nM TBT reduced the amounts of α-ketoglutarate, succinate and malate. We further found that TBT decreased the activity of NAD-dependent isocitrate dehydrogenase (NAD-IDH), which catalyzes the conversion of isocitrate to α-ketoglutarate in the TCA cycle. In addition, TBT inhibited cell growth and enhanced neuronal differentiation through NAD-IDH inhibition. Furthermore, studies using bacterially expressed human NAD-IDH and in silico simulations suggest that TBT inhibits NAD-IDH due to a possible interaction. These results suggest that NAD-IDH is a novel non-genomic target of TBT at nanomolar levels. Thus, a metabolomic approach may provide new insights into the mechanism of EDC action.

  5. Tributyltin chloride induces renal dysfunction by inflammation and oxidative stress in female rats.

    Science.gov (United States)

    Coutinho, João V S; Freitas-Lima, Leandro C; Freitas, Frederico F C T; Freitas, Flávia P S; Podratz, Priscila L; Magnago, Rafaella P L; Porto, Marcella L; Meyrelles, Silvana S; Vasquez, Elisardo C; Brandão, Poliane A A; Carneiro, Maria T W D; Paiva-Melo, Francisca D; Miranda-Alves, Leandro; Silva, Ian V; Gava, Agata L; Graceli, Jones B

    2016-10-17

    Tributyltin chloride (TBT) is an organometallic pollutant that is used as a biocide in antifouling paints. TBT induces several toxic and endocrine-disrupting effects. However, studies evaluating the effects of TBT on renal function are rare. This study demonstrates that TBT exposure is responsible for improper renal function as well as the development of abnormal morphophysiology in mammalian kidneys. Female rats were treated with TBT, and their renal morphophysiology was assessed. Morphophysiological abnormalities such as decreased glomerular filtration rate and increased proteinuria levels were observed in TBT rats. In addition, increases in inflammation, collagen deposition and α-smooth muscle actin (α-SMA) protein expression were observed in TBT kidneys. A disrupted cellular redox balance and apoptosis in kidney tissue were also observed in TBT rats. TBT rats demonstrated reduced serum estrogen levels and estrogen receptor-α (ERα) protein expression in renal cortex. Together, these data provide in vivo evidence that TBT is toxic to normal renal function and that these effects may be associated with renal histopathology complications, such as inflammation and fibrosis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Toxicogenomic analysis identifies the apoptotic pathway as the main cause of hepatotoxicity induced by tributyltin.

    Science.gov (United States)

    Zhou, Mi; Feng, Mei; Fu, Ling-Ling; Ji, Lin-Dan; Zhao, Jin-Shun; Xu, Jin

    2016-11-01

    Tributyltin (TBT) is one of the most widely used organotin biocides, which has severe endocrine-disrupting effects on marine species and mammals. Given that TBT accumulates at higher levels in the liver than in any other organ, and it acts mainly as a hepatotoxic agent, it is important to clearly delineate the hepatotoxicity of TBT. However, most of the available studies on TBT have focused on observations at the cellular level, while studies at the level of genes and proteins are limited; therefore, the molecular mechanisms of TBT-induced hepatotoxicity remains largely unclear. In the present study, we applied a toxicogenomic approach to investigate the effects of TBT on gene expression in the human normal liver cell line HL7702. Gene expression profiling identified the apoptotic pathway as the major cause of hepatotoxicity induced by TBT. Flow cytometry assays confirmed that medium- and high-dose TBT treatments significantly increased the number of apoptotic cells, and more cells underwent late apoptosis in the high-dose TBT group. The genes encoding heat shock proteins (HSPs), kinases and tumor necrosis factor receptors mediated TBT-induced apoptosis. These findings revealed novel molecular mechanisms of TBT-induced hepatotoxicity, and the current microarray data may also provide clues for future studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Enhancement of tributyltin degradation under natural light by N-doped TiO2 photocatalyst

    International Nuclear Information System (INIS)

    Bangkedphol, S.; Keenan, H.E.; Davidson, C.M.; Sakultantimetha, A.; Sirisaksoontorn, W.; Songsasen, A.

    2010-01-01

    Photo-degradation of tributyltin (TBT) has been enhanced by TiO 2 nanoparticles doped with nitrogen (N-doped TiO 2 ). The N-doped catalyst was prepared by a sol-gel reaction of titanium (IV) tetraisopropoxide with 25% ammonia solution and calcined at various temperatures from 300 to 600 deg. C. X-ray diffraction results showed that N-doped TiO 2 remained amorphous at 300 deg. C. At 400 deg. C the anatase phase occurred then transformed to the rutile phase at 600 deg. C. The crystallite size calculated from Scherrer's equation was in the range of 16-51 nm which depended on the calcination temperature. N-doped TiO 2 calcined at 400 deg. C which contained 0.054% nitrogen, demonstrated the highest photocatalytic degradation of TBT at 28% in 3 h under natural light when compared with undoped TiO 2 and commercial photocatalyst, P25-TiO 2 which gave 14.8 and 18% conversion, respectively.

  8. Tributyltin and triphenyltin inhibit osteoclast differentiation through a retinoic acid receptor-dependent signaling pathway

    International Nuclear Information System (INIS)

    Yonezawa, Takayuki; Hasegawa, Shin-ichi; Ahn, Jae-Yong; Cha, Byung-Yoon; Teruya, Toshiaki; Hagiwara, Hiromi; Nagai, Kazuo; Woo, Je-Tae

    2007-01-01

    Organotin compounds, such as tributyltin (TBT) and triphenyltin (TPT), have been widely used in agriculture and industry. Although these compounds are known to have many toxic effects, including endocrine-disrupting effects, their effects on bone resorption are unknown. In this study, we investigated the effects of organotin compounds, such as monobutyltin (MBT), dibutyltin (DBT), TBT, and TPT, on osteoclast differentiation using mouse monocytic RAW264.7 cells. MBT and DBT had no effects, whereas TBT and TPT dose-dependently inhibited osteoclast differentiation at concentrations of 3-30 nM. Treatment with a retinoic acid receptor (RAR)-specific antagonist, Ro41-5253, restored the inhibition of osteoclastogenesis by TBT and TPT. TBT and TPT reduced receptor activator of nuclear factor-κB ligand (RANKL) induced nuclear factor of activated T cells (NFAT) c1 expression, and the reduction in NFATc1 expression was recovered by Ro41-5253. Our results suggest that TBT and TPT suppress osteoclastogenesis by inhibiting RANKL-induced NFATc1 expression via an RAR-dependent signaling pathway

  9. sugE: A gene involved in tributyltin (TBT) resistance of Aeromonas molluscorum Av27.

    Science.gov (United States)

    Cruz, Andreia; Micaelo, Nuno; Félix, Vitor; Song, Jun-Young; Kitamura, Shin-Ichi; Suzuki, Satoru; Mendo, Sónia

    2013-01-01

    The mechanism of bacterial resistance to tributyltin (TBT) is still unclear. The results herein presented contribute to clarify that mechanism in the TBT-resistant bacterium Aeromonas molluscorum Av27. We have identified and cloned a new gene that is involved in TBT resistance in this strain. The gene is highly homologous (84%) to the Aeromonas hydrophila-sugE gene belonging to the small multidrug resistance gene family (SMR), which includes genes involved in the transport of lipophilic drugs. In Av27, expression of the Av27-sugE was observed at the early logarithmic growth phase in the presence of a high TBT concentration (500 μM), thus suggesting the contribution of this gene for TBT resistance. E. coli cells transformed with Av27-sugE become resistant to ethidium bromide (EtBr), chloramphenicol (CP) and tetracycline (TE), besides TBT. According to the Moriguchi logP (miLogP) values, EtBr, CP and TE have similar properties and are substrates for the sugE-efflux system. Despite the different miLogP of TBT, E. coli cells transformed with Av27-sugE become resistant to this compound. So it seems that TBT is also a substrate for the SugE protein. The modelling studies performed also support this hypothesis. The data herein presented clearly indicate that sugE is involved in TBT resistance of this bacterium.

  10. [Effects of tributyltin chloride (TBT) and triphenyltin chloride (TPT) on rat testicular Leydig cells].

    Science.gov (United States)

    Wang, Bao-an; Li, Ming; Mu, Yi-ming; Lu, Zhao-hui; Li, Jiang-yuan

    2006-06-01

    To investigate the effects of tributyltin chloride (TBT) and triphenyltin chloride (TPT) on rat testicular Leydig cells. The rat Leydig cells (LC-540) were incubated with 0 to 80 nmol/L TBT and TPT for 24 to approximately 96 h, and then the cell viability was determined by MTT. DNA fragmentation ladder formation of cell apoptosis was examined by agarose electrophoresis. Effects of chelator of intracellular Ca2+ (BAPTA) and the inhibitors of PKA, PKC and TPK on cell apoptosis induced by TBT were observed. Effects of TBT on testosterone production in primary cultured rat Leydig cells treated with or without hCG were detected. TBT and TPT suppressed Leydig cell survival in a time- and dose-dependent manner. The suppressive effects of TBT and TPT on the cell survival was caused by apoptosis which was determined by DNA ladder formation. The apoptotic effect of TBT was possibly mediated by the rise in intracellular Ca2+ because it could be blocked by BAPTA, the chelator of intracellular Ca2+; PKA, PKC and TPK inhibitors did not prevent the apoptotic effects induced by TBT. TBT markedly suppressed testosterone production of primary cultured rat Leydig cells with or without hCG stimulation. TBT and TPT induced apoptosis in rat testicular Leydig cells possibly through increasing intracellular Ca2+. TBT reduced the testosterone production of rat Leydig cells.

  11. Effect of tributyltin (TBT) in the metabolic activity of TBT-resistant and sensitive estuarine bacteria.

    Science.gov (United States)

    Cruz, Andreia; Oliveira, Vanessa; Baptista, Inês; Almeida, Adelaide; Cunha, Angela; Suzuki, Satoru; Mendo, Sónia

    2012-01-01

    The effect of tributyltin (TBT) on growth and metabolic activity of three estuarine bacteria with different TBT resistance profiles was investigated in an organic-rich culture medium (TSB) and in phosphate buffered saline (PBS) buffer. Exposure to TBT was assessed by determining its effect on growth (OD(600 nm) measurement), bacterial productivity (leucine incorporation), viability (CFU counts), aggregation and cell size (from Live/Dead analysis), ATP and NADH concentrations. TBT exposure resulted in decrease of bacterial density, cell size, and metabolic activity. In addition, cell aggregates were observed in the TBT-treated cultures. TBT strongly affected bacterial cell metabolism and seemed to exert an effect on its equilibrium, interfering with cell activity. Also, TBT toxicity was lower when cells were grown in TSB than in PBS, suggesting that a nutrient-rich growth medium can protect cells from TBT toxicity. This study contributes to our understanding of the TBT-resistant cell behavior reflected in its physiology and metabolic activity. This information is of utmost importance for further studies of TBT bioremediation. Copyright © 2010 Wiley Periodicals, Inc.

  12. Phospholipids and protein adaptation of Pseudomonas sp. to the xenoestrogen tributyltin chloride (TBT).

    Science.gov (United States)

    Bernat, Przemysław; Siewiera, Paulina; Soboń, Adrian; Długoński, Jerzy

    2014-09-01

    A tributyltin (TBT)-resistant strain of Pseudomonas sp. isolated from an overworked car filter was tested for its adaptation to TBT. The isolate was checked for organotin degradation ability, as well as membrane lipid and cellular protein composition in the presence of TBT. The phospholipid profiles of bacteria, grown with and without increased amounts of TBT, were characterized using liquid chromatography/electrospray ionization/mass spectrometry. The strain reacted to the biocide by changing the composition of its phospholipids. TBT induced a twofold decline in the amounts of many molecular species of phosphatidylglycerol and an increase in the levels of phosphatidic acid (by 58%) and phosphatidylethanolamine (by 70%). An increase in the degree of saturation of phospholipid fatty acids of TBT exposed Pseudomonas sp. was observed. These changes in the phospholipid composition and concentration reflect the mechanisms which support optimal lipid ordering in the presence of toxic xenobiotic. In the presence of TBT the abundances of 16 proteins, including TonB-dependent receptors, porins and peroxidases were modified, which could indicate a contribution of some enzymes to TBT resistance.

  13. Reproductive impacts of tributyltin (TBT) and triphenyltin (TPT) in the hermaphroditic freshwater gastropod Lymnaea stagnalis.

    Science.gov (United States)

    Giusti, Arnaud; Barsi, Alpar; Dugué, Maël; Collinet, Marc; Thomé, Jean-Pierre; Joaquim-Justo, Célia; Roig, Benoit; Lagadic, Laurent; Ducrot, Virginie

    2013-07-01

    Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment, they have mainly been tested separately for their effects on snail reproduction. Because large discrepancies in experimental conditions occurred in these tests, the present study aimed to compare the relative toxicity of TBT and TPT under similar laboratory conditions in the range of 0 ng Sn/L to 600 ng Sn/L. Tests were performed on the simultaneous hermaphrodite Lymnaea stagnalis, a freshwater snail in which effects of TPT were unknown. Survival, shell length, and reproduction were monitored in a 21-d semistatic test. Frequency of abnormal eggs was assessed as an additional endpoint. Triphenyltin hampered survival while TBT did not. Major effects on shell solidity and reproduction were observed for both compounds, reproductive outputs being more severely hampered by TBT than by TPT. Considering the frequency of abnormal eggs allowed increasing test sensitivity, because snail responses to TBT could be detected at concentrations as low as 19 ng Sn/L. However, the putative mode of action of the 2 compounds could not be deduced from the structure of the molecules or from the response of apical endpoints. Sensitivity of L. stagnalis to TBT and TPT was compared with the sensitivity of prosobranch mollusks with different habitats and different reproductive strategies. Copyright © 2013 SETAC.

  14. Tributyltin (TBT) inhibition of oligomycin-sensitive Mg-ATPase activity in mussel mitochondria.

    Science.gov (United States)

    Pagliarani, Alessandra; Bandiera, Patrizia; Ventrella, Vittoria; Trombetti, Fabiana; Pirini, Maurizio; Nesci, Salvatore; Borgatti, Anna Rosa

    2008-06-01

    Tributyltin (TBT), one of the most toxic lipophilic aquatic pollutants, can be efficiently incorporated from sea water and sediments by filter-feeding molluscs. As far as we are aware TBT effects on the mitochondrial oligomycin-sensitive Mg-ATPase, the enzymatic core of energy production and a known target of TBT toxicity in mammals, have not been yet investigated in molluscs; thus the hydrolytic capability of the mitochondrial complex in the presence of micromolar concentrations of TBT was assayed in the mussel Mytilus galloprovincialis. Gill and mantle ATPase activities were progressively depressed by increasing TBT doses up to a maximal inhibition (82% in the gills and 74% in the mantle) at 0.62 microM TBT. Non-cooperative inhibition kinetics (n(H) approximately -1) and a non-competitive mechanism with respect to ATP substrate were pointed out. The mitochondrial Mg-ATPase susceptivity to TBT in the marine mussel was consistent with the formation of a TBT-Mg-ATPase complex, apparently more stable in the gills than in the mantle. The complex shape of the dose-response curve and the partial release of Mg-ATPase inhibition within the 0.6-34.4 microM TBT range suggest multiple interactions of TBT with the enzyme complex putatively related to its molecular mechanism of toxicity.

  15. Tributyltin chloride leads to adiposity and impairs metabolic functions in the rat liver and pancreas.

    Science.gov (United States)

    Bertuloso, Bruno D; Podratz, Priscila L; Merlo, Eduardo; de Araújo, Julia F P; Lima, Leandro C F; de Miguel, Emilio C; de Souza, Leticia N; Gava, Agata L; de Oliveira, Miriane; Miranda-Alves, Leandro; Carneiro, Maria T W D; Nogueira, Celia R; Graceli, Jones B

    2015-05-19

    Tributyltin chloride (TBT) is an environmental contaminant used in antifouling paints of boats. Endocrine disruptor effects of TBT are well established in animal models. However, the adverse effects on metabolism are less well understood. The toxicity of TBT in the white adipose tissue (WAT), liver and pancreas of female rats were assessed. Animals were divided into control and TBT (0.1 μg/kg/day) groups. TBT induced an increase in the body weight of the rats by the 15th day of oral exposure. The weight gain was associated with high parametrial (PR) and retroperitoneal (RP) WAT weights. TBT-treatment increased the adiposity, inflammation and expression of ERα and PPARγ proteins in both RP and PR WAT. In 3T3-L1 cells, estrogen treatment reduced lipid droplets accumulation, however increased the ERα protein expression. In contrast, TBT-treatment increased the lipid accumulation and reduced the ERα expression. WAT metabolic changes led to hepatic inflammation, lipid accumulation, increase of PPARγ and reduction of ERα protein expression. Accordingly, there were increases in the glucose tolerance and insulin sensitivity tests with increases in the number of pancreatic islets and insulin levels. These findings suggest that TBT leads to adiposity in WAT specifically, impairing the metabolic functions of the liver and pancreas. Copyright © 2015. Published by Elsevier Ireland Ltd.

  16. Mechanism of Inhibition of the V-Type Molecular Motor by Tributyltin Chloride

    Science.gov (United States)

    Takeda, Mizuho; Suno-Ikeda, Chiyo; Shimabukuro, Katsuya; Yoshida, Masasuke; Yokoyama, Ken

    2009-01-01

    Tributyltin chloride (TBT-Cl) is an endocrine disruptor found in many animal species, and it is also known to be an inhibitor for the V-ATPases that are emerging as potential targets in the treatment of diseases such as osteoporosis and cancer. We demonstrated by using biochemical and single-molecular imaging techniques that TBT-Cl arrests an elementary step for rotary catalysis of the V1 motor domain. In the presence of TBT-Cl, the consecutive rotation of V1 paused for a long duration (∼0.5 s), even at saturated ATP concentrations, and the pausing positions were localized at 120° intervals. Analysis of both the pausing time and moving time revealed that TBT-Cl has little effect on the binding affinity for ATP, but, rather, it arrests the catalytic event(s). This is the first report to demonstrate that an inhibitor arrests an elementary step for rotary catalysis of a V-type ATP-driven rotary motor. PMID:19186155

  17. Tributyltin disrupts feeding and energy metabolism in the goldfish (Carassius auratus).

    Science.gov (United States)

    Zhang, Jiliang; Sun, Ping; Yang, Fan; Kong, Tao; Zhang, Ruichen

    2016-06-01

    Tributyltin (TBT) can induce obesogen response. However, little is known about the adverse effects of TBT on food intake and energy metabolism. The present study was designed to investigate the effects of TBT, at environmental concentrations of 2.44 and 24.4 ng/L (1 and 10 ng/L as Sn), on feeding and energy metabolism in goldfish (Carassius auratus). After exposure for 54 d, TBT increased the weight gain and food intake in fish. The patterns of brain neuropeptide genes expression were in line with potential orexigenic effects, with increased expression of neuropeptide Y and apelin, and decreased expression of pro-opiomelanocortin, ghrelin, cocaine and amphetamine-regulated transcript, and corticotropin-releasing factor. Interestingly, the energy metabolism indicators (oxygen consumption, ammonia exertion and swimming activity) and the serum thyroid hormones were all significantly increased at the 2.44 ng/L TBT group in fish. However, no changes of energy metabolism indicators or a decrease of thyroid hormones was found at the 24.4 ng/L TBT group, which indicated a complex disrupting effect on metabolism of TBT. In short, TBT can alter feeding and energy metabolism in fish, which might promote the obesogenic responses. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. High mortality of the larvae of the common mussel at low concentrations of tributyltin

    Energy Technology Data Exchange (ETDEWEB)

    Beaumont, A.R.; Budd, M.D.

    1984-11-01

    Laboratory reared veliger larvae of the common mussel Mytilus edulis were grown for 15 days in filtered seawater containing 10 ..mu..g l/sup -1/, 1 ..mu..g l/sup -1/ and 0.1 ..mu..g l/sup -1/ tributyltin oxide, (TBTO), the biocide in recent antifouling paint formulations. No larvae survived longer than 5 days in 10 ..mu..g l/sup -1/ TBTO. Approximately half the larvae subjected to 0.1 ..mu..g/sup -1/ TBTO were dead by day 15 (approximately 15 day LC/sub 50/ = 0.1 ..sqrt..g l/sup -1/ TBTO) and most of the surviving larvae were moribund and had grown significantly more slowly than controls. It is noted that current recorded levels of TBT at several UK estuarine sites are higher than 0.1 ..mu..g l/sup -1/ and there has therefore probably been a high mortality of mussel larvae at such sites. The results are discussed in relation to the reported short-term toxicity of organotins to other marine organisms and the value of carrying out longer term tests at low levels of TBT is pointed out.

  19. Low-Concentration Tributyltin Decreases GluR2 Expression via Nuclear Respiratory Factor-1 Inhibition

    Science.gov (United States)

    Ishida, Keishi; Aoki, Kaori; Takishita, Tomoko; Miyara, Masatsugu; Sakamoto, Shuichiro; Sanoh, Seigo; Kimura, Tomoki; Kanda, Yasunari; Ohta, Shigeru; Kotake, Yaichiro

    2017-01-01

    Tributyltin (TBT), which has been widely used as an antifouling agent in paints, is a common environmental pollutant. Although the toxicity of high-dose TBT has been extensively reported, the effects of low concentrations of TBT are relatively less well studied. We have previously reported that low-concentration TBT decreases α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptor subunit 2 (GluR2) expression in cortical neurons and enhances neuronal vulnerability to glutamate. However, the mechanism of this TBT-induced GluR2 decrease remains unknown. Therefore, we examined the effects of TBT on the activity of transcription factors that control GluR2 expression. Exposure of primary cortical neurons to 20 nM TBT for 3 h to 9 days resulted in a decrease in GluR2 mRNA expression. Moreover, TBT inhibited the DNA binding activity of nuclear respiratory factor-1 (NRF-1), a transcription factor that positively regulates the GluR2. This result indicates that TBT inhibits the activity of NRF-1 and subsequently decreases GluR2 expression. In addition, 20 nM TBT decreased the expression of genes such as cytochrome c, cytochrome c oxidase (COX) 4, and COX 6c, which are downstream of NRF-1. Our results suggest that NRF-1 inhibition is an important molecular action of the neurotoxicity induced by low-concentration TBT. PMID:28800112

  20. Tributyltin induces mitochondrial fission through NAD-IDH dependent mitofusin degradation in human embryonic carcinoma cells.

    Science.gov (United States)

    Yamada, Shigeru; Kotake, Yaichiro; Nakano, Mizuho; Sekino, Yuko; Kanda, Yasunari

    2015-08-01

    Organotin compounds, such as tributyltin (TBT), are well-known endocrine disruptors. TBT acts at the nanomolar level through genomic pathways via the peroxisome proliferator activated receptor (PPAR)/retinoid X receptor (RXR). We recently reported that TBT inhibits cell growth and the ATP content in the human embryonic carcinoma cell line NT2/D1 via a non-genomic pathway involving NAD(+)-dependent isocitrate dehydrogenase (NAD-IDH), which metabolizes isocitrate to α-ketoglutarate. However, the molecular mechanisms by which NAD-IDH mediates TBT toxicity remain unclear. In the present study, we evaluated the effects of TBT on mitochondrial NAD-IDH and energy production. Staining with MitoTracker revealed that nanomolar TBT levels induced mitochondrial fragmentation. TBT also degraded the mitochondrial fusion proteins, mitofusins 1 and 2. Interestingly, apigenin, an inhibitor of NAD-IDH, mimicked the effects of TBT. Incubation with an α-ketoglutarate analogue partially recovered TBT-induced mitochondrial dysfunction, supporting the involvement of NAD-IDH. Our data suggest that nanomolar TBT levels impair mitochondrial quality control via NAD-IDH in NT2/D1 cells. Thus, mitochondrial function in embryonic cells could be used to assess cytotoxicity associated with metal exposure.

  1. Quantitative determination of creatine kinase release from herring (Clupea harengus) spermatozoa induced by tributyltin.

    Science.gov (United States)

    Grzyb, Katarzyna; Rychłowski, Michał; Biegniewska, Anna; Skorkowski, Edward F

    2003-02-01

    Creatine kinase (CK, ATP creatine phosphotransferase, EC 2.7.3.2) is an enzyme participating in ATP regeneration, which is the primary source of energy in living organisms. We demonstrated that CK from herring spermatozoa has high activity ( approximately 452 micromol/min/g of fresh semen) and has a different electrophoretic mobility from isoenzymes present in skeletal muscle. In our study, we investigated toxic effect of tributyltin (TBT) on herring spermatozoa using a specific sperm viability kit to observe live and dead sperm cells with a confocal microscope. Treatment of herring spermatozoa with TBT caused a time-dependent decrease of viability: 35% nonviable cells with 5 microM TBT and more than 90% nonviable cells with 10 microM TBT after 6 h exposure. We also monitored CK release from damaged spermatozoa into surrounding medium containing different concentrations of TBT. The higher concentration of TBT was used the more CK release from spermatozoa was observed. We suggest that CK could be a good biomarker of sperm cell membranes degradation in the case when lactate dehydrogenase release from permeabilized cells is not possible for rapid determination of the effect of TBT.

  2. Toxicity of triphenyltin and tributyltin to the freshwater mudsnail Potamopyrgus antipodarum in a new sediment biotest.

    Science.gov (United States)

    Duft, Martina; Schulte-Oehlmann, Ulrike; Tillmann, Michaela; Markert, Bernd; Oehlmann, Jörg

    2003-01-01

    The effects of two suspected endocrine-disrupting chemicals, the xeno-androgens triphenyltin (TPT) and tributyltin (TBT), were investigated in a new whole-sediment biotest with the freshwater mudsnail Potamopyrgus antipodarum (Gastropoda, Prosobranchia). Artificial sediments were spiked with seven concentrations, ranging from 10 to 500 microg nominal TPT-Sn/kg dry weight and TBT-Sn/kg dry weight, respectively. We analyzed the responses of the test species after two, four, and eight weeks exposure. For both compounds, P. antipodarum exhibited a sharp decline in the number of embryos sheltered in its brood pouch in a time- and concentration-dependent manner in comparison to the control sediment. The number of new, still unshelled embryos turned out to be the most sensitive parameter. The lowest-observed-effect concentration (LOEC) was equivalent to the lowest administered concentration (10 microg/kg of each test compound) for most parameters and thus no no-observed-effect concentration (NOEC) could be established. The calculation of effect concentrations (EC10) resulted in even lower values for both substances (EC10 after eight weeks for unshelled embryos: 0.03 microg TPT-Sn/kg, EC10 after four weeks for unshelled embryos: 0.98 microg TBT-Sn/kg). Our results indicate that P. antipodarum is highly sensitive to both endocrine disruptors TPT and TBT at environmentally relevant concentrations.

  3. Effect of tributyltin on trout blood cells: changes in mitochondrial morphology and functionality.

    Science.gov (United States)

    Tiano, Luca; Fedeli, Donatella; Santoni, Giorgio; Davies, Ian; Falcioni, Giancarlo

    2003-05-12

    The aquatic environment is the largest sink for the highly toxic organotin compounds, particularly as one of the main sources is the direct release of organotins from marine antifouling paints. The aim of this study was to investigate the mitochondrial toxicity and proapoptotic activity of tributyltin chloride (TBTC) in teleost leukocytes and nucleated erythrocytes, by means of electron microscopy investigation and mitochondrial membrane potential evaluation, in order to provide an early indicator of aquatic environmental pollution. Erythrocytes and leukocytes were obtained from an inbred strain of rainbow trout (Oncorhynchus mykiss). Transmission electronic micrographs of trout red blood cells (RBC) incubated in the presence of TBTC at 1 and 5 microM for 60 min showed remarkable mitochondrial morphological changes. TBTC-mediated toxicity involved alteration of the cristae ultrastructure and mitochondrial swelling, in a dose-dependent manner. Both erythrocytes and leukocytes displayed a consistent drop in mitochondrial membrane potential following TBTC exposure at concentrations >1 microM. The proapoptotic effect of TBTC on fish blood cells, and involvement of mitochondrial pathways was also investigated by verifying the release of cytochrome c, activation of caspase-3 and the presence of "DNA laddering". Although mitochondrial activity was much more strongly affected in erythrocytes, leukocytes incubated in the presence of TBTC showed the characteristic features of apoptosis after only 1 h of incubation. Longer exposures, up to 12 h, were required to trigger an apoptotic response in erythrocytes.

  4. Chronic exposure to Tributyltin induces brain functional damage in juvenile common carp (Cyprinus carpio).

    Science.gov (United States)

    Li, Zhi-Hua; Li, Ping; Shi, Ze-Chao

    2015-01-01

    The aim of the present study was to investigate the effect of Tributyltin (TBT) on brain function and neurotoxicity of freshwater teleost. The effects of long-term exposure to TBT on antioxidant related indices (MDA, malondialdehyde; SOD, superoxide dismutase; CAT, catalase; GR, glutathione reductase; GPx, glutathione peroxidase), Na+-K+-ATPase and neurological parameters (AChE, acetylcholinesterase; MAO, monoamine oxidase; NO, nitric oxide) in the brain of common carp were evaluated. Fish were exposed to sublethal concentrations of TBT (75 ng/L, 0.75 μg/L and 7.5 μg/L) for 15, 30, and 60 days. Based on the results, a low level and short-term TBT-induced stress could not induce the notable responses of the fish brain, but long-term exposure (more than 15 days) to TBT could lead to obvious physiological-biochemical responses (based on the measured parameters). The results also strongly indicated that neurotoxicity of TBT to fish. Thus, the measured physiological responses in fish brain could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity.

  5. Testosterone metabolism in the estuarine mysid Neomysis integer (Crustacea; Mysidacea) following tributyltin exposure.

    Science.gov (United States)

    Verslycke, Tim; Poelmans, Sofie; De Wasch, Katia; Vercauteren, Jordy; Devos, Christophe; Moens, Luc; Sandra, Patrick; De Brabander, Hubert F; Janssen, Colin R

    2003-09-01

    Current evidence suggests that the biocide tributyltin (TBT) causes the development of imposex, a state of pseudohermaphrodism in which females exhibit functional secondary male characteristics, by altering the biotransformation or elimination of testosterone. Imposex in gastropods following TBT exposure is the most complete example of the effects of an endocrine disrupter on marine invertebrates. Previous studies have demonstrated that the estuarine mysid Neomysis integer converts testosterone into multiple polar and nonpolar metabolites resulting from both phase I and phase II biotransformations. In this study, the effects of TBT chloride (TBTCl) on the phase I and II testosterone metabolism of N. integer were evaluated. The TBTCl was highly toxic to N. integer (96-h median lethal concentration [LC50] of 164 ng/L). To assess the effects on testosterone metabolism, mysids were exposed for 96 h to different concentrations of TBTCl (control, 10, 100, and 1,000 ng/L), and testosterone elimination as polar hydroxylated, nonpolar oxido-reduced, and glucose- and sulfate-conjugated metabolites was examined. The TBTCl differentially affected testosterone metabolism. The effect of TBTCl on phase I metabolism was unclear and has been shown to vary among species, likely depending on the inducibility or presence of certain P450 isozyme families. Reductase activity and metabolic androgenization were induced in the 10-ng/L treatment, whereas higher concentrations resulted in a reduction of sulfate conjugation. The exact mechanisms underlying TBT-induced imposex and alterations in the steroid metabolism need to be further elucidated.

  6. Inhibitory effect of tributyltin on expression of steroidogenic enzymes in mouse testis.

    Science.gov (United States)

    Kim, Suel-Kee; Kim, Jong-Hoon; Han, Jung Ho; Yoon, Yong-Dal

    2008-01-01

    Tributyltin (TBT) is known to disrupt the development of reproductive organs, thereby reducing fertility. The aim of this study was to evaluate the acute toxicity of TBT on the testicular development and steroid hormone production. Immature (3-week-old) male mice were given a single administration of 25, 50, or 100 mg/kg of TBT by oral gavage. Lumen formation in seminiferous tubule was remarkably delayed, and the number of apoptotic germ cells found inside the tubules was increased in the TBT-exposed animals, whereas no apoptotic signal was observed in interstitial Leydig cells. Reduced serum testosterone concentration and down-regulated expressions of the mRNAs for cholesterol side-chain cleavage enzyme (P450scc), 17alpha -hydroxylase/C(17-20) lyase (P450(17alpha)), 3beta -hydroxysteroid-dehydrogenase (3beta -HSD), and 17beta -hydroxysteroid-dehydrogenase (17beta -HSD) were also observed after TBT exposure. Altogether, these findings demonstrate that exposure to TBT is associated with induced apoptosis of testicular germ cells and inhibition of steroidogenesis by reduction in the expression of steroidogenic enzymes in interstitial Leydig cells. These adverse effects of TBT would cause serious defects in testicular development and function.

  7. Two-generation reproductive toxicity study of tributyltin chloride in female rats.

    Science.gov (United States)

    Ogata, R; Omura, M; Shimasaki, Y; Kubo, K; Oshima, Y; Aou, S; Inoue, N

    2001-05-25

    A two-generation reproductive toxicity study of the effects of tributyltin chloride (TBTCl) was conducted in female rats using dietary concentrations of 5, 25, and 125 ppm TBTCl. Reproductive outcomes of dams (number and body weight of pups and the percentage of live pups) and the growth of female pups (the day of eye opening and body weight gain) were significantly decreased in the 125 ppm TBTCl group. A delay in vaginal opening and impaired estrous cyclicity were also observed in the 125 ppm TBTCl group. However, an increase in anogenital distance was found in all TBTCl groups on postnatal d 1. A dose-effect relationship was observed in TBTCl-induced changes in anogenital distance. These results indicate that the whole-life exposure to TBTCl affects the sexual development and reproductive function of female rats. In addition, the TBTCl-induced increase in anogenital distance seems to suggest it may exert a masculinizing effect on female neonates. However, the concentrations of TBTCl used in this study are not environmentally relevant.

  8. Tributyltin toxicity in abalone (Haliotis diversicolor supertexta) assessed by antioxidant enzyme activity, metabolic response, and histopathology.

    Science.gov (United States)

    Zhou, Jin; Zhu, Xiao-shan; Cai, Zhong-hua

    2010-11-15

    A toxicity test was performed to investigate the possible harmful effects of tributyltin (TBT) on abalone (Haliotis diversicolor supertexta). Animals were exposed to TBT in a range of environmentally relevant concentrations (2, 10 and 50 ng/L) for 30 days under laboratory conditions. TBT-free conditions were used as control treatments. The activity of antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD), and malondialdehyde (MDA), along with levels of haemolymph metabolites, and hepatopancreas histopathology were analyzed. The results showed that TBT decreased SOD activity, and increased POD level and MDA production in a dose-dependent way, indicating that oxidative injury was induced by TBT. Haemolymph metabolite measurements showed that TBT increased alanine and glutamate levels, and decreased glucose content, which suggested perturbation of energy metabolism. Elevated levels of acetate and pyruvate in the haemolymph indicated partial alteration of lipid metabolism. A decrease in lactate and an increase in succinate, an intermediate of the tricarboxylic acid (TCA) cycle, indicated disturbance of amino acid metabolism. Hepatopancreas tissues also exhibited inflammatory responses characterized by histopathological changes such as cell swelling, granular degeneration, and inflammation. Taken together, these results demonstrated that TBT was a potential toxin with a variety of deleterious effects on abalone. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Improved radioiodination of 1,2-dipalmitoyl-3-IPPA via a tributyltin intermediate

    Energy Technology Data Exchange (ETDEWEB)

    McPherson, D.W. E-mail: phm@oml.gov; Luo, H.; Kropp, J.; Knapp, F.F

    1999-10-01

    1,2-Palmitoyl-3-[15-(4-iodophenyl)pentadecan-3-oyl]-rac-glyceroI (MIPAG) is a new agent for the clinical evaluation of pancreatic lipase activity and has demonstrated promise in preliminary clinical studies with patients affected with pancreatic insufficiency. Iodine-131-MIPAG was initially prepared via thallium-iodide displacement. Because of the need for a simple method which is amendable for the routine clinical use of MIPAG we have investigated the preparation and radioiodination of MIPAG utilizing the tributyltin precursor, 1,2-palmitoyl-3-[15-(-4-tributylstannylphenyl)pentadecan-3-oyl] -rac-glyceroI (TBT-MIPAG, 2). Compound 2 was prepared via the condensation of 1,2-palmitoyl-rac-glycerol with 15-(4-tributylstannylphenyl)pentadecanoic acid (TBT-PPA) prepared from 4-bromophenylacetylene. Electrophilic radioiodination using peracetic acid with sodium iodide-125 in ethanol at 80 deg. C for 60 min afforded I-125-MIPAG in 65.9% ({+-}11.5%) yield and radiochemical purity of 94% ({+-}3.0%) after C-18 Sep-Pak purification (n=6). This improved method for radioiodination utilizing TBT-MIPAG now provides radioiodinated MIPAG for routine clinical evaluation.

  10. The effect of tributyltin on human eosinophilic [correction of eosinophylic] leukemia EoL-1 cells.

    Science.gov (United States)

    Sroka, Jolanta; Włosiak, Przemysław; Wilk, Anna; Antonik, Justyna; Czyz, Jarosław; Madeja, Zbigniew

    2008-01-01

    Organotin compounds are chemicals that are widely used in industry and agriculture as plastic stabilizers, catalysts and biocides. Many of them, including tributyltin (TBT), have been detected in human food and, as a consequence, detectable levels have been found in human blood. As organotin compounds were shown to possess immunotoxic activity, we focused our attention on the effect of TBT on the basic determinants of the function of eosinophils, i.e. cell adhesiveness and motility. We used human eosinophylic leukemia EoL-1 cells, a common in vitro cellular model of human eosinophils. Here, we demonstrate that TBT causes a dose-dependent decrease in the viability of EoL-1 cells. When administered at sub-lethal concentrations, TBT significantly decreases the adhesion of EoL-1 cells to human fibroblasts (HSFs) and inhibits their migration on fibroblast surfaces. Since the basic function of eosinophils is to invade inflamed tissues, our results indicate that TBT, and possibly other organotin compounds, may affect major cellular properties involved in the determination of in vivo eosinophil function.

  11. Tributyltin--critical pollutant in whole water samples--development of traceable measurement methods for monitoring under the European Water Framework Directive (WFD) 2000/60/EC.

    Science.gov (United States)

    Richter, Janine; Fettig, Ina; Philipp, Rosemarie; Jakubowski, Norbert

    2015-07-01

    Tributyltin is listed as one of the priority substances in the European Water Framework Directive (WFD). Despite its decreasing input in the environment, it is still present and has to be monitored. In the European Metrology Research Programme project ENV08, a sensitive and reliable analytical method according to the WFD was developed to quantify this environmental pollutant at a very low limit of quantification. With the development of such a primary reference method for tributyltin, the project helped to improve the quality and comparability of monitoring data. An overview of project aims and potential analytical tools is given.

  12. Determination of total mercury and methylmercury in biological samples by photochemical vapor generation

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Mariana A.; Ribeiro, Anderson S.; Curtius, Adilson J. [Universidade Federal de Santa Catarina, Departamento de Quimica, Florianopolis, SC (Brazil); Sturgeon, Ralph E. [National Research Council Canada, Institute for National Measurement Standards, Ottawa, ON (Canada)

    2007-06-15

    Cold vapor atomic absorption spectrometry (CV-AAS) based on photochemical reduction by exposure to UV radiation is described for the determination of methylmercury and total mercury in biological samples. Two approaches were investigated: (a) tissues were digested in either formic acid or tetramethylammonium hydroxide (TMAH), and total mercury was determined following reduction of both species by exposure of the solution to UV irradiation; (b) tissues were solubilized in TMAH, diluted to a final concentration of 0.125% m/v TMAH by addition of 10% v/v acetic acid and CH{sub 3}Hg{sup +} was selectively quantitated, or the initial digests were diluted to 0.125% m/v TMAH by addition of deionized water, adjusted to pH 0.3 by addition of HCl and CH{sub 3}Hg{sup +} was selectively quantitated. For each case, the optimum conditions for photochemical vapor generation (photo-CVG) were investigated. The photochemical reduction efficiency was estimated to be {proportional_to}95% by comparing the response with traditional SnCl{sub 2} chemical reduction. The method was validated by analysis of several biological Certified Reference Materials, DORM-1, DORM-2, DOLT-2 and DOLT-3, using calibration against aqueous solutions of Hg{sup 2+}; results showed good agreement with the certified values for total and methylmercury in all cases. Limits of detection of 6 ng/g for total mercury using formic acid, 8 ng/g for total mercury and 10 ng/g for methylmercury using TMAH were obtained. The proposed methodology is sensitive, simple and inexpensive, and promotes ''green'' chemistry. The potential for application to other sample types and analytes is evident. (orig.)

  13. Total Mercury and Methylmercury Contamination in Fish from Sites along the Elbe River

    Directory of Open Access Journals (Sweden)

    P. Maršálek

    2006-01-01

    Full Text Available The aim of the study was to evaluate total mercury Hg and methylmercury MeHg contamination in muscle tissues of fish collected in 2002 from the Labe (Elbe river at sites upstream of Pardubice and downstream of Pardubice and Hřensko, and in 2004 from the Labe river upstream and downstream of the Spolana factory in Neratovice, and from the Vltava river downstream of Lenora. Eighty eight fish of the following species were sampled: bream (Abramis brama L., perch (Perca fluviatilis L., chub (Leuciscus cephalus L. and barbel (Barbus barbus L.. Total mercury content in chub, perch and bream was in the range of 0.05 - 1.96 mg kg-1 w.w., 0. 09 - 1.46 mg kg-1 w.w. and 0.35 - 0.82 mg kg-1 w.w., respectively. Methylmercury content in chub, perch and bream was in the range of 0.04 - 2.11 mg kg-1 w.w., 0.1 - 1.73 mg kg-1 w.w. and 0.371 - 0.650 mg kg-1 w.w., respectively. Significant correlation (p p < 0.05 between THg and MeHg contents were found between individual sites. In 2002, for example, the most contaminated fish were found downstream of Pardubice, followed by fish from upstream of Pardubice and from Hřensko. In 2004, fish from downstream and upstream of the Spolana factory in Neratovice were more contaminated than fish from the Vltava river downstream of Lenora. The methylmercury-tototal mercury ratio in muscle tissue was close to 1.0.

  14. Methylmercury decomposition in sediments and bacterial cultures: Involvement of methanogens and sulfate reducers in oxidative demethylation

    International Nuclear Information System (INIS)

    Oremland, R.S.; Culbertson, C.W.; Winfrey, M.R.

    1991-01-01

    The biogeochemical cycling of mercury has received considerable attention because of the toxicity of methylmercury, its bioaccumulation in biota, and its biomagnification in aquatic food chains. The formation of methylmercury is mediated primarily by microorganisms. Demethylation of monomethylmercury in freshwater and estuarine sediments and in bacterial cultures was investigated with 14 CH 3 HgI. Under anaerobiosis, results with inhibitors indicated partial involvement of both sulfate reducers and methanogens, the former dominated estuarine sediments, while both were active in freshwaters. Aerobes were the most significant demethylators in estuarine sediments, but were unimportant in freshwater sediments. Products of anaerobic demthylation were mainly 14 CO 2 as well as lesser amounts of 14 CH 4 . Acetogenic activity resulted in fixation of some 14 CO 2 produced from 14 CH 3 HgI into acetate. Aerobic demethylation in estuarine sediments produced only 14 CH 4 , while aerobic demethylation in freshwater sediments produced small amounts of both 14 CH 4 and 14 CO 2 . Two species of Desulfovibrio produced only traces of 14 CH 4 from 14 CH 3 HgI, while a culture of a methylotrophic methanogen formed traces of 14 CO 2 and 14 CH 4 when grown on trimethylamine in the presence of the 14 CH 3 HgI. These results indicate that both aerobes and anaerobes demethylate mercury in sediments, but that either group may dominate in a particular sediment type. Aerobic demethylation in the estuarine sediments appeared to proceed by the previously characterized organomercurial-lyase pathway, because methane was the sole product. This indicates the presence of an oxidative pathway, possibly one in which methylmercury serves as an analog of one-carbon substrates

  15. Microsolvation of methylmercury: structures, energies, bonding and NMR constants ((199)Hg, (13)C and (17)O).

    Science.gov (United States)

    Flórez, Edison; Maldonado, Alejandro F; Aucar, Gustavo A; David, Jorge; Restrepo, Albeiro

    2016-01-21

    Hartree-Fock (HF) and second order perturbation theory (MP2) calculations within the scalar and full relativistic frames were carried out in order to determine the equilibrium geometries and interaction energies between cationic methylmercury (CH3Hg(+)) and up to three water molecules. A total of nine structures were obtained. Bonding properties were analyzed using the Quantum Theory of Atoms In Molecules (QTAIM). The analyses of the topology of electron densities reveal that all structures exhibit a partially covalent HgO interaction between methylmercury and one water molecule. Consideration of additional water molecules suggests that they solvate the (CH3HgOH2)(+) unit. Nuclear magnetic shielding constants σ((199)Hg), σ((13)C) and σ((17)O), as well as indirect spin-spin coupling constants J((199)Hg-(13)C), J((199)Hg-(17)O) and J((13)C-(17)O), were calculated for each one of the geometries. Thermodynamic stability and the values of NMR constants correlate with the ability of the system to directly coordinate oxygen atoms of water molecules to the mercury atom in methylmercury and with the formation of hydrogen bonds among solvating water molecules. Relativistic effects account for 11% on σ((13)C) and 14% on σ((17)O), which is due to the presence of Hg (heavy atom on light atom, HALA effect), while the relativistic effects on σ((199)Hg) are close to 50% (heavy atom on heavy atom itself, HAHA effect). J-coupling constants are highly influenced by relativity when mercury is involved as in J((199)Hg-(13)C) and J((199)Hg-(17)O). On the other hand, our results show that the values of NMR constants for carbon and oxygen, atoms which are connected through mercury (C-HgO), are highly correlated and are greatly influenced by the presence of water molecules. Water molecules introduce additional electronic effects to the relativistic effects due to the mercury atom.

  16. Biological effects of methylmercury dicyandiamide-treated grain in the domestic fowl Gallus gallus L

    Energy Technology Data Exchange (ETDEWEB)

    Tejning, S

    1967-01-01

    This exhaustive study of chickens begins with studies of food consumption, egg production, and general health. Next, the problem of shell-less eggs is discussed. The mercury content in eggs in relation to mercury content in diet and duration of methylmercury feeding, along with intra-egg distribution of mercury, and the biological accumulation of mercury by various organs are also dealt with. The symptoms of alimentary poisoning are described, and embryonic mortality and hatching frequency are also discussed. 155 references, 25 figures, 49 tables.

  17. Morphological effects of tributyltin (TBT) in vitro on the genital system of the mesogastropoda Littorina littorea (Prosobranchia)

    Science.gov (United States)

    Deutsch, U.; Brick, M.

    1993-02-01

    This ultrastructural study investigates the pathological changes in the penial, the sperm groove and the glandular cushion epithelium in male Littorina littorea (Mesogastropoda) related to TBT (tributyltin) contamination. The results are compared with those on Ocinebrina aciculata (Neogastropoda), which shows a wide range of cell changes in the penis epithelia of male and imposex affected females. The investigation of the different penis epithelia of L. littorea revealed that the cells analysed show a low sensibility towards TBT. The cells display normal metabolism. Certain atypical structures like swelling microvilli and cristae which tend to lie parallel to the long axis in the mitochondria, were detected as pathological effects.

  18. Extremely Preterm Birth

    Science.gov (United States)

    ... Events Advocacy For Patients About ACOG Extremely Preterm Birth Home For Patients Search FAQs Extremely Preterm Birth ... Spanish FAQ173, June 2016 PDF Format Extremely Preterm Birth Pregnancy When is a baby considered “preterm” or “ ...

  19. Exposure to tributyltin induces endoplasmic reticulum stress and the unfolded protein response in zebrafish.

    Science.gov (United States)

    Komoike, Yuta; Matsuoka, Masato

    2013-10-15

    Tributyltin (TBT) is a major marine contaminant and causes endocrine disruption, hepatotoxicity, immunotoxicity, and neurotoxicity. However, the molecular mechanisms underlying the toxicity of TBT have not been fully elucidated. We examined whether exposure to TBT induces the endoplasmic reticulum (ER) stress response in zebrafish, a model organism. Zebrafish-derived BRF41 fibroblast cells were exposed to 0.5 or 1 μM TBT for 0.5-16 h and subsequently lysed and immunoblotted to detect ER stress-related proteins. Zebrafish embryos, grown until 32 h post fertilization (hpf), were exposed to 1 μM TBT for 16 h and used in whole mount in situ hybridization and immunohistochemistry to visualize the expression of ER chaperones and an ER stress-related apoptosis factor. Exposure of the BRF41 cells to TBT caused phosphorylation of the zebrafish homolog of protein kinase RNA-activated-like ER kinase (PERK), eukaryotic translation initiation factor 2 alpha (eIF2α), and inositol-requiring enzyme 1 (IRE1), characteristic splicing of X-box binding protein 1 (XBP1) mRNA, and enhanced expression of activating transcription factor 4 (ATF4) protein. In TBT-exposed zebrafish embryos, ectopic expression of the gene encoding zebrafish homolog of the 78 kDa glucose-regulating protein (GRP78) and gene encoding CCAAT/enhancer-binding protein homologous protein (CHOP) was detected in the precursors of the neuromast, which is a sensory organ for detecting water flow and vibration. Our in vitro and in vivo studies revealed that exposure of zebrafish to TBT induces the ER stress response via activation of both the PERK-eIF2α and IRE1-XBP1 pathways of the unfolded protein response (UPR) in an organ-specific manner. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Determination of tributyltin in whole water matrices under the European Water Framework Directive.

    Science.gov (United States)

    Richter, Janine; Fettig, Ina; Philipp, Rosemarie; Jakubowski, Norbert; Panne, Ulrich; Fisicaro, Paola; Alasonati, Enrica

    2016-08-12

    Monitoring of water quality is important to control water pollution. Contamination of the aquatic system has a large effect on human health and the environment. Under the European Water Framework Directive (WFD) 2000/60/EC and the related directive on environmental quality standards (EQS) in the field of water policy 2008/105/EC, the need for sensitive reference methods was highlighted. Since tributyltin (TBT) is one of the WFD listed priority substances a method was developed which is capable to qualify and quantify the pollutant at the required low WFD EQS of 0.2ngL(-1) in whole water bodies, i.e. in non-filtered water samples with dissolved organic carbon and suspended particulate matter. Therefore special attention was paid on the interaction of TBT with the suspended particulate matter and humic substances to obtain a complete representation of the pollution in surface waters. Different water samples were investigated varying the content of organic dissolved and suspended matter. Quantification was performed using species-specific isotope dilution (SSID) and gas chromatography with inductively coupled plasma mass spectrometry (GC-ICP-MS). Different sample treatment strategies were evaluated and compared. The process of internal standard addition was investigated and optimized, hence the equilibrium between internal standards and matrix is of primary importance to perform accurate SSID. Samples spiked at EQS level were analyzed with a recovery between 95 and 105 %. Additionally real surface water samples were investigated and the TBT concentration for the whole water body was determined and compared with conventional routine analysis method. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Trophic transfer and in vivo immunotoxicological effects of tributyltin (TBT) in polar seastar Leptasterias polaris

    International Nuclear Information System (INIS)

    Bekri, Khalida; Pelletier, Emilien

    2004-01-01

    This study investigated the potential in vivo immunotoxic effects of tributyltin (TBT) on amoebocytes of 6-armed seastar Leptasterias polaris. Tested animals were contaminated by trophic transfer via alive contaminated prey consisting of blue mussels (3 μg TBT g -1 wet weight (WW) tissue) exposed to seawater containing dissolved TBT. Four biomarkers of immunotoxicological effects were monitored over 45 days at different sampling times (9, 24, 48 and 72 h, 11, 18, 25, 32 and 45 days): amoebocytes count (AC), cell viability using Trypan blue exclusion test, phagocytic activity (PA) using a suspension of dead bacteria labelled with fluorescein isothiocyanate (FITC) and injected directly in the coelomic fluid of the animals, and lysosomal integrity (LI) using the neutral red (NR) retention test. Data showed that TBT and its metabolites (DBT and MBT) bioaccumulated preferentially in pyloric caeca, whereas gonads contained only small quantities. Despite the differences in exposure periods to the contaminated diet and in burdens of butyltins (BTs) ingested by the various contaminated groups, there were no significant differences in body burdens of BTs. Only 6.2±2.0% of total ingested BTs were retained in soft tissues of seastars. Even if butyltins were not detected in the coelomic fluid (CF), their detrimental effects have been detected in the phagocytic activity of amoebocytes and their lysosomal retention of neutral red, but no effects were observed on amoebocytes count and their viability. These results show that seastar L. polaris possesses adequate mechanisms to depurate ingested TBT without supporting major disturbances of its immune defence system. By their ability to digest whole contaminated prey and eliminate only dissolved metabolites, L. polaris and other seastars with the same preying mode could play a role of 'recycling organisms' in coastal environments where toxicants, such as butyltins and other metallic species are accumulated by bivalves and

  2. Chronic effects of tributyltin on multiple biomarkers responses in juvenile common carp, Cyprinus carpio.

    Science.gov (United States)

    Li, Zhi-Hua; Li, Ping; Shi, Ze-Chao

    2016-08-01

    In this study, the chronic toxic effects of tributyltin (TBT), an antifouling paints commonly present in surface and ground water, on morphological indices, reactive oxygen species (ROS) generation, and ATPase activity and heat shock protein (Hsp) 70 protein in tissues (liver, gill, and white muscle) of common carp were investigated. Fish were exposed at sublethal concentrations of TBT (75 ng/L, 0.75 μg/L, and 7.5 μg/L) for 60 days. When compared with the control, there was significant lower condition factor in fish exposed at the higher concentration of TBT. ROS levels in three tissues increased significantly at higher TBT concentrations (0.75 and 7.5 μg/L). The hepatic antioxidant enzymes (total antioxidative capacity and superoxide dismutase) activities were induced at higher concentrations (0.75 μg/L) of TBT. When compared with the hepatic antioxidant enzymes activities in fish exposed to 0.75 μg/L of TBT, there was a decreasing trend in those exposed to TBT with a concentration of 7.5 μg/L. However, all the antioxidant enzymes activities were significantly inhibited in gill and muscle of fish exposed to higher TBT concentrations (0.75 and 7.5 μg/L). Moreover, there was significant lower Na-K-ATPase in three tissues after long-term exposure to higher concentration of TBT, but a significant higher Hsp70 protein levels was observed. In short, environmental concentrations of TBT could not induce obvious impacts on fish, but long-term exposure to higher concentrations of TBT could affect seriously the health status of fish. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 937-944, 2016. © 2015 Wiley Periodicals, Inc.

  3. Tributyltin-induced endoplasmic reticulum stress and its Ca(2+)-mediated mechanism.

    Science.gov (United States)

    Isomura, Midori; Kotake, Yaichiro; Masuda, Kyoichi; Miyara, Masatsugu; Okuda, Katsuhiro; Samizo, Shigeyoshi; Sanoh, Seigo; Hosoi, Toru; Ozawa, Koichiro; Ohta, Shigeru

    2013-10-01

    Organotin compounds, especially tributyltin chloride (TBT), have been widely used in antifouling paints for marine vessels, but exhibit various toxicities in mammals. The endoplasmic reticulum (ER) is a multifunctional organelle that controls post-translational modification and intracellular Ca(2+) signaling. When the capacity of the quality control system of ER is exceeded under stress including ER Ca(2+) homeostasis disruption, ER functions are impaired and unfolded proteins are accumulated in ER lumen, which is called ER stress. Here, we examined whether TBT causes ER stress in human neuroblastoma SH-SY5Y cells. We found that 700nM TBT induced ER stress markers such as CHOP, GRP78, spliced XBP1 mRNA and phosphorylated eIF2α. TBT also decreased the cell viability both concentration- and time-dependently. Dibutyltin and monobutyltin did not induce ER stress markers. We hypothesized that TBT induces ER stress via Ca(2+) depletion, and to test this idea, we examined the effect of TBT on intracellular Ca(2+) concentration using fura-2 AM, a Ca(2+) fluorescent probe. TBT increased intracellular Ca(2+) concentration in a TBT-concentration-dependent manner, and Ca(2+) increase in 700nM TBT was mainly blocked by 50μM dantrolene, a ryanodine receptor antagonist (about 70% inhibition). Dantrolene also partially but significantly inhibited TBT-induced GRP78 expression and cell death. These results suggest that TBT increases intracellular Ca(2+) concentration by releasing Ca(2+) from ER, thereby causing ER stress. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Tributyltin alters secretion of interleukin 1 beta from human immune cells.

    Science.gov (United States)

    Brown, Shyretha; Whalen, Margaret

    2015-08-01

    Tributyltin (TBT) has been used as a biocide in industrial applications such as wood preservation, antifouling paint and antifungal agents. Owing to its many uses, it contaminates the environment and has been found in human blood samples. Interleukin-1 beta (IL-1β) is a pro-inflammatory cytokine that promotes cell growth, tissue repair and immune response regulation. Produced predominately by both monocytes and macrophages, IL-1β appears to increase the invasiveness of certain tumors. This study shows that TBT modifies the secretion of IL-1β from increasingly reconstituted preparations of human immune cells. IL-1β secretion was examined after 24-, 48-h or 6-day exposures to TBT in highly enriched human natural killer (NK) cells, monocyte-depleted peripheral blood mononuclear cells (MD-PBMCs), PBMCs, granulocytes and a preparation combining both PBMCs and granulocytes (PBMCs+granulocytes). TBT altered IL-1β secretion from all of the cell preparations. The 200 nM concentration of TBT normally blocked the secretion of IL-1β, whereas lower concentrations (usually 5-50 nM) elevated secretion of IL-1β. Examination of the signaling pathway(s) responsible for the elevated secretion of IL-1β was carried out in MD-PBMCs. Pathways examined were IL-1β processing (Caspase-1), mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NFκB). Results indicated that MAPK pathways (p44/42 and p38) appear to be the targets of TBT that lead to increased IL-1β secretion from immune cells. These results from human immune cells show IL-1β dysregulation by TBT is occurring ex vivo. Thus, the potential for in vivo effects on pro-inflammatory cytokine levels may possibly be a consequence of TBT exposures. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Transcriptomic analyses of tributyltin-induced sexual dimorphisms in rare minnow (Gobiocypris rarus) brains.

    Science.gov (United States)

    Zhang, Ji-Liang; Liu, Min; Zhang, Chun-Nuan; Li, Er-Chao; Fan, Ming-Zhen; Huang, Mao-Xian

    2018-07-30

    The brain of fish displays sexual dimorphisms and exhibits remarkable sexual plasticity throughout their life span. Although reproductive toxicity of tributyltin (TBT) in fish is well documented in fish, it remains unknown whether TBT interrupts sexual dimorphisms of fish brains. In this work, brain transcriptomic profiles of rare minnow (Gobiocypris rarus) was characterized and sex-biased genes were identified using RNA sequencing. Functional annotation and enrichment analysis were performed to reveal differences of gene products and pathways between the brains of male and female fish. Furthermore, transcriptomic responses of male and female brains to TBT at 10 ng/L were also investigated to understand effects of TBT on brain sexual dimorphisms. Only 345 male-biased and 273 female-biased genes were found in the brains. However, significant female-biased pathways of circadian rhythm and phototransduction were identified in the brains by enrichment analysis. Interestingly, following TBT exposure in the female fish, the circadian rhythm pathway was significantly disrupted based on enrichment analysis, while in the male fish, the phototransduction pathway was significantly disrupted. In the female fish, expression of genes (Per, Cry, Rev-Erb α, Ror, Dec and CK1δ/ε) in the circadian rhythm pathway was down-regulated after TBT exposure; while in the male fish, expression of genes (Rec, GNAT1_2, GNGT1, Rh/opsin, PDE and Arr) in the phototransduction pathway was up-regulated after TBT exposure. Overall, our results not only provide key data on the molecular basis of brain sexual dimorphisms in fish, but also offer valuable resources for investigating molecular mechanisms by which environmental chemicals might influence brain sexual plasticity. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Screening of ovarian steroidogenic pathway in Ciona intestinalis and its modulation after tributyltin exposure

    International Nuclear Information System (INIS)

    Cangialosi, Maria Vittoria; Puccia, Egidio; Mazzola, Antonio; Mansueto, Valentina; Arukwe, Augustine

    2010-01-01

    In this study, we have identified several ovarian steroids in Ciona with high similarity to vertebrate steroids and showed that cholesterol, corticosterone, dehydroepiandrosterone, estrone, estradiol-17β, testosterone, pregnenolone, progesterone, have identical molecular spectra with vertebrate steroids. In addition, we have studied the effects of an endocrine disruptor (tributyltin: TBT) on these sex hormones and their precursors, ovarian morphology, and gene expression of some key enzymes in steroidogenic pathway in the ovary of Ciona. Ovarian specimens were cultured in vitro using different concentrations of TBT (10 -5 , 10 -4 and 10 -3 M). Ethanol was used as solvent control. Gene expression analysis was performed for adrenodoxin (ADREN) and adrenodoxin reductase (ADOX) (mediators of acute steroidogenesis) and 17β-hydroxysteroid dehydrogenase (17β-HSD). These transcripts were detected and measured by quantitative (real-time) polymerase chain reaction (qPCR). Sex steroids and their precursors were identified and quantified by a gas chromatography-mass spectroscopy (GC-MS) method. Exposure of Ciona ovaries to TBT produced modulations (either increased or decreased) of sterols and sex steroid levels, whereas no significant differences in ADREN, ADOX or 17β-HSD mRNA expression patterns were observed. Histological analysis shows that TBT produced several modifications on Ciona ovarian morphology that includes irregular outline of nuclear membrane, less compacted cytoplasm, in addition to test and granulosa cells that were detached from the oocyte membrane. Given that the ascidians represent very simple experimental models for the study of endocrine disruption by environmental contaminants, our findings provide excellent models for multiple identification and quantification of sex steroid and their precursors in biological samples exposed to endocrine-disrupting chemicals and for direct extrapolation of such effects across taxonomic groups and phyla. In addition

  7. Tributyltin affects shoaling and anxiety behavior in female rare minnow (Gobiocypris rarus).

    Science.gov (United States)

    Zhang, Jiliang; Zhang, Chunnuan; Sun, Ping; Shao, Xian

    2016-09-01

    Effects of tributyltin (TBT) on reproduction are well established in many fish species. However, few studies report the effects of TBT on non-reproductive behaviors, which is a novel aspect of endocrine disruption in fish. Thus, the present study used rare minnow (Gobiocypris rarus) to investigate the effects of TBT, at environmental concentrations of 1, 10 and 100ng/L, on shoaling and anxiety behaviors. The results showed that fish exposed to TBT had less group cohesion during the course of the 10-min observation period as compared with the control fish. Further, TBT altered the shoaling in the Novel tank test, where shoaling is determined as the tendency to leave a shoal of littermates trapped behind a Plexiglas barrier at one end of the test tank. Fish exposed to TBT had shorter latency before leaving shoal mates and spent more time away from shoal than control fish. In addition, we also used Novel tanks to study the anxiety behavior as the tendency to stay at the bottom when introduced into an unfamiliar environment. The fish exposed to TBT showed increased anxiety, manifested as increased latency to enter the upper half and decreased time in upper half when compared with the control fish. TBT exposure increased the levels of dopamine and its metabolite 3,4-dihydroxyphenylacetic acid, and decreased the levels of 5-hydroxytryptamine and its metabolite 5-hydroxy indole acetic acid in the brain. Thus, the hypofunction of the dopaminergic system or of the serotoninergic system or the combination of the two may underlie the observed behavioral change, which might affect the fitness of fish in their natural environment. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Secretion of interferon gamma from human immune cells is altered by exposure to tributyltin and dibutyltin.

    Science.gov (United States)

    Lawrence, Shanieek; Reid, Jacqueline; Whalen, Margaret

    2015-05-01

    Tributyltin (TBT) and dibutyltin (DBT) are widespread environmental contaminants found in food, beverages, and human blood samples. Both of these butyltins (BTs) interfere with the ability of human natural killer (NK) cells to lyse target cells and alter secretion of the pro-inflammatory cytokine tumor necrosis factor alpha (TNFα) from human immune cells in vitro. The capacity of BTs to interfere with secretion of other pro-inflammatory cytokines has not been examined. Interferon gamma (IFNγ) is a modulator of adaptive and innate immune responses, playing an important role in overall immune competence. This study shows that both TBT and DBT alter secretion of IFNγ from human immune cells. Peripheral blood cell preparations that were increasingly reconstituted were used to determine if exposures to either TBT or DBT affected IFNγ secretion and how the makeup of the cell preparation influenced that effect. IFNγ secretion was examined after 24 h, 48 h, and 6 day exposures to TBT (200 - 2.5 nM) and DBT (5 - 0.05 µM) in highly enriched human NK cells, a monocyte-depleted preparation of PBMCs, and monocyte-containing PBMCs. Both BTs altered IFNγ secretion from immune cells at most of the conditions tested (either increasing or decreasing secretion). However, there was significant variability among donors as to the concentrations and time points that showed changes as well as the baseline secretion of IFNγ. The majority of donors showed an increase in IFNγ secretion in response to at least one concentration of TBT or DBT at a minimum of one length of exposure. © 2013 Wiley Periodicals, Inc.

  9. Tributyltin exposure at noncytotoxic doses dysregulates pancreatic β-cell function in vitro and in vivo.

    Science.gov (United States)

    Chen, Ya-Wen; Lan, Kuo-Cheng; Tsai, Jing-Ren; Weng, Te-I; Yang, Ching-Yao; Liu, Shing-Hwa

    2017-09-01

    Tributyltin (TBT) is an endocrine disruptor. TBT can be found in food and in human tissues and blood. Several animal studies revealed that organotins induced diabetes with decreased insulin secretion. The detailed effect and mechanism of TBT on pancreatic β-cell function still remain unclear. We investigated the effect and mechanism of TBT exposure at noncytotoxic doses relevant to human exposure on β-cell function in vitro and in vivo. The β-cell-derived RIN-m5F cells and pancreatic islets from mouse and human were treated with TBT (0.05-0.2 μM) for 0.5-4 h. Adult male mice were orally exposed to TBT (25 μg/kg/day) with or without antioxidant N-acetylcysteine (NAC) for 1-3 weeks. Assays for insulin secretion and glucose metabolism were carried out. Unlike previous studies, TBT at noncytotoxic concentrations significantly increased glucose-stimulated insulin secretion and intracellular Ca 2+ ([Ca 2+ ] i ) in β-cells. The reactive oxygen species (ROS) production and phosphorylation of protein kinase C (PKC-pan) and extracellular signal-regulated kinase (ERK)1/2 were also increased. These TBT-triggered effects could be reversed by antiestrogen ICI182780 and inhibitors of ROS, [Ca 2+ ] i , and PKC, but not ERK. Similarly, islets treated with TBT significantly increased glucose-stimulated insulin secretion, which could be reversed by ICI182780, NAC, and PKC inhibitor. Mice exposed to TBT for 3 weeks significantly increased blood glucose and plasma insulin and induced glucose intolerance and insulin resistance, which could be reversed by NAC. These findings suggest that low/noncytotoxic doses of TBT induce insulin dysregulation and disturb glucose homeostasis, which may be mediated through the estrogen receptor-regulated and/or oxidative stress-related signaling pathways.

  10. Fluorescence X-ray microscopy on hydrated tributyltin-clay mineral suspensions

    Science.gov (United States)

    Neuhäusler, U.; Schmidt, C.; Hoch, M.; Susini, J.

    2003-03-01

    Using the scanning transmission X-ray microscope at ID21 beamline of the ESRF in fluorescence mode, we mapped tin at a bulk concentration of 1000 μg(Sn)/ml within hydrated tributyltin (TBT)-clay mineral (Kaolinite) dispersion with sub-300 nm spatial resolution. Using the L absorption edges of tin at 3929, 4156 and 4465 eV fluorescence radiation was excited in tin atoms with incident photon energies of 4 and 4.5 keV. When using 4 keV radiation, only tin fluorescence is excited. For 4.5 keV X rays, both the fluorescence of tin and calcium (which is present in the solid phase) can be measured. Methodologically, we were interested in assessing and proving the possibilities and limitations of fluorescence mapping using the L absorption edges of tin, where the fluorescence yield is significantly lower compared to other elements with their K edges in the same energy range. Scientifically, organotin-clay mineral interactions are of environmental concern because this factor influences significantly the distribution of toxic TBT in the aquatic System. On one hand, the half-life of TBT deposited to the sediment phase increases, and consequently the time of its bioavailability. On the other hand, the adsorption process is reversible, which means that contaminated sediments can act as a source of pollution. The adsorption and desorption effects can be studied directly with high spatial resolution and brought into connection to the surface properties of the clay mineral under study as well as to other experimental parameters, like pH or salinity.

  11. Ecotoxicological evaluation of tributyltin toxicity to the equilateral venus clam, Gomphina veneriformis (Bivalvia: Veneridae).

    Science.gov (United States)

    Park, Kiyun; Kim, Rosa; Park, Jung Jun; Shin, Hyun Chool; Lee, Jung Sick; Cho, Hyeon Seo; Lee, Yeon Gyu; Kim, Jongkyu; Kwak, Inn-Sil

    2012-03-01

    Tributyltin (TBT) is the most common pesticide in marine and freshwater environments. To evaluate the potential ecological risk posed by TBT, we measured biological responses such as growth rate, gonad index, sex ratio, the percentage of intersex gonads, filtration rate, and gill abnormalities in the equilateral venus clam (Gomphina veneriformis). Additionally, the biochemical and molecular responses were evaluated in G. veneriformis exposed to various concentrations of TBT. The growth of G. veneriformis was significantly delayed in a dose-dependent manner after exposure to all tested TBT concentrations. After TBT was administered to G. veneriformis, the gonad index decreased and the sex balance was altered. The percentage of intersex gonads also increased significantly in treated females, whereas no intersex gonads were detected in the solvent control group. Additionally, intersex gonads were detected in male G. veneriformis specimens exposed to relatively high TBT concentrations (20 μg L⁻¹). The filtration rate was also reduced in a dose-dependent manner in TBT-exposed G. veneriformis. We also noted abnormal gill morphology in TBT-exposed G. veneriformis. Furthermore, increases in antioxidant enzyme activities were observed in TBT-exposed G. veneriformis clams, regardless of dosage. Vitellogenin gene expression also increased significantly in a dose-dependent manner in G. veneriformis exposed to TBT. These results provide valuable information regarding our understanding of the toxicology of TBT in G. veneriformis. Moreover, the responses of biological and molecular factors could be utilized as information for risk assessments and marine monitoring of TBT toxicity. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  12. The effect of tributyltin-oxide on earthworms, springtails, and plants in artificial and natural soils.

    Science.gov (United States)

    Römbke, J; Jänsch, S; Junker, T; Pohl, B; Scheffczyk, A; Schallnass, H-J

    2007-05-01

    Chemical bioavailability in Organisation for Economic Co-operation and Development (OECD) artificial soil can contrast with bioavailability in natural soils and produce ecotoxicologic benchmarks that are not representative of species' exposure conditions in the field. Initially, reproduction and growth of earthworm and Collembolan species, and early seedling growth of a dicotyledonous plant species, in nine natural soils (with a wide range of physicochemical properties) and in OECD soil were evaluated. Soils that supported reproduction and growth of the test species were then used to investigate the toxicity of tributyltin-oxide (TBT-O). Natural soils caused greater toxicity of TBT-O to earthworms (EC(50) values varied from 0.5 to 4.7 mg/kg soil dry weight [dw]) compared with toxicity in OECD soil (EC(50) = 13.4 mg/kg dw). Collembolans were less sensitive to TBT-O than earthworms in natural soils, with EC(50) values ranging from 23.4 to 177.8 mg/kg dw. In contrast, the toxicity of TBT-O to collembolans in OECD soil (EC(50) = 104.0 mg/kg dw) was within the range of EC(50) values in natural soils. Phytotoxicity tests revealed even greater difference between the effects in natural soils (EC(50) values ranged from 10.7 to 189.2 mg/kg dw) and in OECD soil (EC(50) = 535.5 mg/kg dw) compared with results of the earthworm tests. Studies also showed that EC(50) values were a more robust end point compared with EC(10) values based on comparisons of coefficients of variation. These results show that toxicity testing should include studies with natural soils in addition to OECD soil to better reflect exposure conditions in the field.

  13. Impaired growth in the polychaete Armandia brevis exposed to tributyltin in sediment.

    Science.gov (United States)

    Meador, J P; Rice, C A

    2001-03-01

    Juveniles of the opheliid polychaete, Armandia brevis, were exposed to sediment-associated tributyltin (TBT) for 42 days to evaluate toxicity and bioaccumulation. Growth in this species was inhibited in a dose-response fashion by increasing concentrations of TBT. Even though the biota-sediment accumulation factor (BSAF) for TBT declined for the higher sediment concentrations, the total butyltins in tissue increased over all sediment concentrations. At the highest sediment concentrations, polychaetes bioaccumulated less TBT than expected, which was most likely due to reduced uptake and continued metabolism of the parent compound. The less than expected BSAF values exhibited by animals at the exposure concentrations causing severe effects are an important finding for assessing responses in the field. It appears that severe biological effects can occur in long-term experiments without the expected high tissue concentrations; an observation likely explained by altered toxicokinetics. Analysis of variance determined the lowest observed effect concentration for growth to be 191 ng/g sediment dry wt. for 21 days of exposure and 101 ng/g sediment dry wt. at day 42, indicating that 21 days was insufficient for delineating the steady-state toxicity response. When based on regression analysis, the sediment concentration causing a 25% inhibition in growth at 42 days exposure was 93 ng/g dry wt. (total organic carbon = 0.58%). A dose-response association was also determined for polychaete net weight and TBT in tissue. The tissue residue associated with a 25% reduction in growth was 2834 ng/g dry wt. at day 42. A comparison of these results with previous work indicates that juveniles are approximately three times more sensitive than adults to TBT exposure. The sediment concentrations affecting growth in this species are commonly found in urban waterways indicating potentially severe impacts for this and other sensitive species.

  14. Mercury and methylmercury stream concentrations in a Coastal Plain watershed: a multi-scale simulation analysis.

    Science.gov (United States)

    Knightes, C D; Golden, H E; Journey, C A; Davis, G M; Conrads, P A; Marvin-DiPasquale, M; Brigham, M E; Bradley, P M

    2014-04-01

    Mercury is a ubiquitous global environmental toxicant responsible for most US fish advisories. Processes governing mercury concentrations in rivers and streams are not well understood, particularly at multiple spatial scales. We investigate how insights gained from reach-scale mercury data and model simulations can be applied at broader watershed scales using a spatially and temporally explicit watershed hydrology and biogeochemical cycling model, VELMA. We simulate fate and transport using reach-scale (0.1 km(2)) study data and evaluate applications to multiple watershed scales. Reach-scale VELMA parameterization was applied to two nested sub-watersheds (28 km(2) and 25 km(2)) and the encompassing watershed (79 km(2)). Results demonstrate that simulated flow and total mercury concentrations compare reasonably to observations at different scales, but simulated methylmercury concentrations are out-of-phase with observations. These findings suggest that intricacies of methylmercury biogeochemical cycling and transport are under-represented in VELMA and underscore the complexity of simulating mercury fate and transport. Published by Elsevier Ltd.

  15. Recovery of aquatic insect-mediated methylmercury flux from ponds following drying disturbance.

    Science.gov (United States)

    Chumchal, Matthew M; Drenner, Ray W; Greenhill, Frank M; Kennedy, James H; Courville, Ashlyn E; Gober, Charlie A A; Lossau, Luke O

    2017-08-01

    Small ponds exist across a permanence gradient, and pond permanence is hypothesized to be a primary determinant of insect community structure and insect-mediated methylmercury (MeHg) flux from ponds to the surrounding terrestrial landscape. The present study describes the first experiment examining the recovery of insect-mediated MeHg flux following a drying disturbance that converted permanent ponds with insectivorous fish to semipermanent ponds without fish. Floating emergence traps were used to collect emergent insects for 10 wk in the spring and summer from 5 ponds with fish (permanent) and 5 ponds that were drained to remove fish, dried, and refilled with water (semipermanent). During the 73-d period after semipermanent ponds were refilled, total MeHg flux from semipermanent ponds was not significantly different than total MeHg flux from permanent ponds, indicating that insect-mediated MeHg flux had rapidly recovered in semipermanent ponds following the drying disturbance. Methylmercury fluxes from dragonflies (Odonata: Anisoptera) and phantom midges (Diptera: Chaoboridae) were significantly greater from newly refilled semipermanent ponds than permanent ponds, but the MeHg fluxes from the other 8 emergent insect taxa did not differ between treatments. The present study demonstrates the impact of drying disturbance and the effect of community structure on the cross-system transport of contaminants from aquatic to terrestrial ecosystems. Environ Toxicol Chem 2017;36:1986-1990. © 2017 SETAC. © 2017 SETAC.

  16. Evaluation of mercury, selenium and methylmercury in fish consumed by Santos Bay communities, Sao Paulo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Luciana A.; Favaro, Deborah I.T. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: lufarias@usp.br; Azevedo, Juliana de S.; Braga, Elisabete S. [Sao Paulo Univ., SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos no Mar (LABNUT)]. E-mail: juliana@io.usp.br

    2005-07-01

    In the present study, mercury and selenium levels were evaluated in fish tissues and fish organs in the Santos Bay, Sao Paulo State, southeastern Brazil. Santos Bay waters are polluted by the large industrial complex of Cubatao. The estuary system filters part of this pollution before it reaches the Bay. Mercury and methylmercury determination were performed using Cold Vapor Atomic Absorption Spectrometry (CV-AAS) and selenium determination by Instrumental Neutron Activation Analysis (INAA). Methodology validation for the determination of these elements was carried out by means of reference materials analyses. There was no significant correlation between mercury and selenium concentrations (n = 17, (r2 ) R2 = 0.3482, p = 0.1709) in Cathorops spixii (bagre amarelo)- Ariidae family and Centropomus sp. (robalo)- Centropomidae family livers. Mercury and methylmercury concentrations in muscle from carnivorous species: Ariidae Cathorops spixii (bagre amarelo), Scianidae Steliffer rastifer (cangoa) and Scianidae Paralonchurus brasiliensis (maria-luiza) were determined and discussed. Total mercury concentration in Ariidae Catharops spixii livers presented the highest Hg level (7.6 mg kg-1). Although the Santos Bay is less contaminated than the inner section of its estuary system (Cubatao), it presents signs of environmental impact. (author)

  17. Influence of eutrophication on the distribution of total mercury and methylmercury in hydroelectric reservoirs.

    Science.gov (United States)

    Meng, Bo; Feng, X B; Chen, C X; Qiu, G L; Sommar, J; Guo, Y N; Liang, P; Wan, Q

    2010-01-01

    The distribution of mercury (Hg) and the characteristics of its methylation were investigated in Wujiangdu (WJD) and Yinzidu (YZD) reservoirs in Guizhou province, China. The two reservoirs are characterized by high and low levels of primary productivity, respectively. Mercury species in water samples from depth profiles in both reservoirs and from interface water in the WJD were analyzed each season during 2007. The concentrations of total Hg (HgT(unf)) and methylmercury (MeHgT(unf)) in unfiltered water samples from the WJD varied from 3.0 to 18 pmol dm(-3) and from 0.17 to 15 pmol dm(-3), respectively; ranges were 2.0 to 9.5 pmol dm(-3) for HgT(unf) and 0.14 to 2.2 pmol dm(-3) for MeHgT(unf) in the YZD. Elevated methylmercury concentrations in water samples from the bottom water and water-sediment interface demonstrated an active net Hg methylation in the downstream reach of the WJD. There was no discernable Hg methylation occurring in the YZD, nor in the upstream and middle reaches of the WJD. The results suggest that high primary productivity resulting from cage aquaculture activities in the WJD is an important control on Hg methylation in the reservoir, increasing the concentrations of MeHg in water in the Wujiang River basin Southwestern China.

  18. Development of a transgenic tobacco plant for phytoremediation of methylmercury pollution.

    Science.gov (United States)

    Nagata, Takeshi; Morita, Hirofumi; Akizawa, Toshifumi; Pan-Hou, Hidemitsu

    2010-06-01

    To develop the potential of plant for phytoremediation of methylmercury pollution, a genetically engineered tobacco plant that coexpresses organomercurial lyase (MerB) with the ppk-specified polyphosphate (polyP) and merT-encoding mercury transporter was constructed by integrating a bacterial merB gene into ppk/merT-transgenic tobacco. A large number of independent transgenic tobaccos was obtained, in some of which the merB gene was stably integrated in the plant genome and substantially translated to the expected MerB enzyme in the transgenic tobacco. The ppk/merT/merB-transgenic tobacco callus showed more resistance to methylmercury (CH3Hg+) and accumulated more mercury from CH3Hg+-containing medium than the ppk/merT-transgenic and wild-type progenitors. These results suggest that the MerB enzyme encoded by merB degraded the incorporated CH3Hg+ to Hg2+, which then accumulated as a less toxic Hg-polyP complex in the tobacco cells. Phytoremediation of CH3Hg+ and Hg2+ in the environment with this engineered ppk/merT/merB-transgenic plant, which prevents the release mercury vapor (Hg0) into the atmosphere in addition to generating potentially recyclable mercury-rich plant residues, is believed to be more acceptable to the public than other competing technologies, including phytovolatilization.

  19. Ecological risk of methylmercury to piscivorous fish of the Great Lakes region.

    Science.gov (United States)

    Sandheinrich, Mark B; Bhavsar, Satyendra P; Bodaly, R A; Drevnick, Paul E; Paul, Eric A

    2011-10-01

    Contamination of fish populations with methylmercury is common in the region of the Laurentian Great Lakes as a result of atmospheric deposition and methylation of inorganic mercury. Using fish mercury monitoring data from natural resource agencies and information on tissue concentrations injurious to fish, we conducted a screening-level risk assessment of mercury to sexually mature female walleye (Sander vitreus), northern pike (Esox lucius), smallmouth bass (Micropterus dolomieu), and largemouth bass (Micropterus salmoides) in the Great Lakes and in interior lakes, impoundments, and rivers of the Great Lakes region. The assessment included more than 43,000 measurements of mercury in fish from more than 2000 locations. Sexually mature female fish that exceeded threshold-effect tissue concentrations of 0.20 μg g(-1) wet weight in the whole body occurred at 8% (largemouth bass) to 43% (walleye) of sites. Fish at 3% to 18% of sites were at risk of injury and exceeded 0.30 μg g(-1) where an alteration in reproduction or survival is predicted to occur. Most fish at increased risk were from interior lakes and impoundments. In the Great Lakes, no sites had sexually mature fish that exceeded threshold-effect concentrations. Results of this screening-level assessment indicate that fish at a substantive number of locations within the Great Lakes region are potentially at risk from methylmercury contamination and would benefit from reduction in mercury concentrations.

  20. Speciation of methylmercury in rice grown from a mercury mining area

    Energy Technology Data Exchange (ETDEWEB)

    Li Lu [Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing100085 (China); Wang Feiyue, E-mail: wangf@ms.umanitoba.c [Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Meng Bo [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Road, Guiyang, Guizhou 550002 (China); Lemes, Marcos [Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Feng Xinbin [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Road, Guiyang, Guizhou 550002 (China); Jiang Guibin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing100085 (China)

    2010-10-15

    Monomethylmercury (CH{sub 3}Hg{sup +} and its complexes; MeHg hereafter) is a known developmental neurotoxin. Recent studies have shown that rice (Oryza sativa L.) grain grown from mercury (Hg) mining areas may contain elevated MeHg concentrations, raising concerns over the health of local residents who consume rice on a daily basis. An analytical method employing high performance liquid chromatography (HPLC) - inductively coupled plasma mass spectrometry (ICP-MS) following enzymatic hydrolysis was developed to analyze the speciation of MeHg in uncooked and cooked white rice grain grown from the vicinity of a Hg mine in China. The results revealed that the MeHg in the uncooked rice is present almost exclusively as CH{sub 3}Hg-L-cysteinate (CH{sub 3}HgCys), a complex that is thought to be responsible for the transfer of MeHg across the blood-brain and placental barriers. Although cooking does not change the total Hg or total MeHg concentration in rice, no CH{sub 3}HgCys is measurable after cooking, suggesting that most, if not all, of the CH{sub 3}HgCys is converted to other forms of MeHg, the identity and toxicity of which remain elusive. - Methylmercury in uncooked rice occurs predominantly as methylmercury-L-cysteinate, which is effectively removed during the cooking process.

  1. Evaluation of mercury, selenium and methylmercury in fish consumed by Santos Bay communities, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Farias, Luciana A.; Favaro, Deborah I.T.; Azevedo, Juliana de S.; Braga, Elisabete S.

    2005-01-01

    In the present study, mercury and selenium levels were evaluated in fish tissues and fish organs in the Santos Bay, Sao Paulo State, southeastern Brazil. Santos Bay waters are polluted by the large industrial complex of Cubatao. The estuary system filters part of this pollution before it reaches the Bay. Mercury and methylmercury determination were performed using Cold Vapor Atomic Absorption Spectrometry (CV-AAS) and selenium determination by Instrumental Neutron Activation Analysis (INAA). Methodology validation for the determination of these elements was carried out by means of reference materials analyses. There was no significant correlation between mercury and selenium concentrations (n = 17, (r2 ) R2 = 0.3482, p = 0.1709) in Cathorops spixii (bagre amarelo)- Ariidae family and Centropomus sp. (robalo)- Centropomidae family livers. Mercury and methylmercury concentrations in muscle from carnivorous species: Ariidae Cathorops spixii (bagre amarelo), Scianidae Steliffer rastifer (cangoa) and Scianidae Paralonchurus brasiliensis (maria-luiza) were determined and discussed. Total mercury concentration in Ariidae Catharops spixii livers presented the highest Hg level (7.6 mg kg-1). Although the Santos Bay is less contaminated than the inner section of its estuary system (Cubatao), it presents signs of environmental impact. (author)

  2. Certification of the methylmercury content in SRM 2977 mussel tissue (organic contaminants and trace elements) and SRM 1566b oyster tissue.

    Science.gov (United States)

    Tutschku, S; Schantz, M M; Horvat, M; Logar, M; Akagi, H; Emons, H; Levenson, M; Wise, S A

    2001-02-01

    The methylmercury content in two new marine bivalve mollusk tissue Standard Reference Materials (SRMs) has been certified using results of analyses from the National Institute of Standards and Technology (NIST) and two other laboratories. The certified concentrations of methylmercury were established based on the results from four and six different (independent) analytical methods, respectively, for SRM 1566b Oyster Tissue (13.2 +/- 0.7 microg/kg) and SRM 2977 Mussel Tissue (organic contaminants and trace elements) (36.2 +/- 1.7 microg/kg). The certified concentration of methylmercury in SRM 1566b is among the lowest in any certified reference material (CRM).

  3. Validation of a method to determine methylmercury in fish tissues using gas chromatography; Validacion de un metodo para determinar metilmercurio en tejido de pescado por cromatografia de gases

    Energy Technology Data Exchange (ETDEWEB)

    Vega Bolannos, Luisa O; Arias Verdes, Jose A; Beltran Llerandi, Gilberto; Castro Diaz, Odalys; Moreno Tellez, Olga L [Instituto de Nutricion e Higiene de los Alimentos, La Habana (Cuba)

    2000-07-01

    We validated a method to determine methylmercury in fish tissues using gas chromatography with an electron capture detector as described by the Association of Official Analytical Chemist (AOAC) International. The linear curve range was 0.02 to 1 g/ml and linear correlation coefficient was 0.9979. A 1 mg/kg methylmercury-contaminated fish sample was analyzed 20 times to determine repeatability of the method. The quantification limit was 0.16 mg/kg and detection limit was 0.06 ppm. Fish samples contaminated with 0.2 to 10 mg/kg methylmercury showed recovery indexes from 94.66 to 108.8%.

  4. Effects of two-hour exposure to environmental and high concentrations of methylmercury on the transcriptome of the macrophyte Elodea nuttallii.

    Science.gov (United States)

    Beauvais-Flück, Rebecca; Slaveykova, Vera I; Cosio, Claudia

    2018-01-01

    The effects of two methylmercury (CH 3 Hg + , MeHg) concentrations, representative of environmental level and extreme contamination, were investigated on the macrophyte Elodea nuttallii during a 2h-exposure combining transcriptomic (RNA-Seq), physiological endpoints (pigment contents, activity of anti-oxidative stress enzymes) and bioaccumulation. Exposure to MeHg induced the up- and down-regulation of numerous genes (4389 and 16853 for 10ngL -1 and 10μgL -1 MeHg exposure, respectively) involved in sugar, amino acid and secondary metabolism (e.g. cinnamic acid, flavonoids) at both concentrations. Genes coding for photosynthesis, membrane integrity, metal homeostasis, water transport and anti-oxidative enzymes were additionally up- and down-regulated at the higher concentration. At the physiological level, exposure to both MeHg concentrations resulted in a strong increase of anthocyanin content in shoots. Chlorophyll content and antioxidant enzyme activities were unchanged. The data suggest that the macrophyte was able to efficiently cope with the stress resulting from MeHg exposure, possibly by using anthocyanin as anti-oxidant and S-rich amino acids (such as cysteine and methionine) as chelators. Transcriptomics analysis enabled gaining novel insights on molecular effects of MeHg in primary producers, which are one of the main entry pathway of hazardous MeHg in aquatic food webs. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Determination of methylmercury by electrothermal atomic absorption spectrometry using headspace single-drop microextraction with in situ hydride generation

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Sandra [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Universidad de Vigo, Facultad de Ciencias (Quimica), As Lagoas-Marcosende s/n, 36200 Vigo (Spain); Fragueiro, Sandra [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Universidad de Vigo, Facultad de Ciencias (Quimica), As Lagoas-Marcosende s/n, 36200 Vigo (Spain); Lavilla, Isela [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Universidad de Vigo, Facultad de Ciencias (Quimica), As Lagoas-Marcosende s/n, 36200 Vigo (Spain); Bendicho, Carlos [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Universidad de Vigo, Facultad de Ciencias (Quimica), As Lagoas-Marcosende s/n, 36200 Vigo (Spain)]. E-mail: bendicho@uvigo.es

    2005-01-10

    A new method is proposed for preconcentration and matrix separation of methylmercury prior to its determination by electrothermal atomic absorption spectrometry (ETAAS). Generation of methylmercury hydride (MeHgH) from a 5-ml solution is carried out in a closed vial and trapped onto an aqueous single drop (3-{mu}l volume) containing Pd(II) or Pt(IV) (50 and 10 mg/l, respectively). The hydrogen evolved in the headspace (HS) after decomposition of sodium tetrahydroborate (III) injected for hydride generation caused the formation of finely dispersed Pd(0) or Pt(0) in the drop, which in turn, were responsible for the sequestration of MeHgH. A preconcentration factor of ca. 40 is achieved with both noble metals used as trapping agents. The limit of detection of methylmercury was 5 and 4 ng/ml (as Hg) with Pd(II) or Pt(IV) as trapping agents, and the precision expressed as relative standard deviation was about 7%. The preconcentration system was fully characterised through optimisation of the following variables: Pd(II) or Pt(IV) concentration in the drop, extraction time, pH of the medium, temperatures of both sample solution and drop, concentration of salt in the sample solution, sodium tetrahydroborate (III) concentration in the drop and stirring rate. The method has been successfully validated against two fish certified reference materials (CRM 464 tuna fish and CRM DORM-2 dogfish muscle) following selective extraction of methylmercury in 2 mol/l HCl medium.

  6. RETROSPECTIVE STUDY OF METHYLMERCURY AND OTHER METAL(LOID)S IN MADAGASCAR UNPOLISHED RICE (Oryza sativa L.)

    Science.gov (United States)

    Rothenberg, Sarah E.; Mgutshini, Noma L.; Bizimis, Michael; Johnson-Beebout, Sarah E.; Ramanantsoanirina, Alain

    2014-01-01

    The rice ingestion rate in Madagascar is among the highest globally; however studies concerning metal(loid) concentrations in Madagascar rice are lacking. For Madagascar unpolished rice (n=51 landraces), levels of toxic elements (e.g., total mercury, methylmercury, arsenic and cadmium) as well as essential micronutrients (e.g., zinc and selenium) were uniformly low, indicating potentially both positive and negative health effects. Aside from manganese (Wilcoxon rank sum, p<0.01), no significant differences in concentrations for all trace elements were observed between rice with red bran (n=20) and brown bran (n=31) (Wilcoxon rank sum, p=0.06–0.91). Compared to all elements in rice, rubidium (i.e., tracer for phloem transport) was most positively correlated with methylmercury (Pearson's r=0.33, p<0.05) and total mercury (r=0.44, p<0.05), while strontium (i.e., tracer for xylem transport) was least correlated with total mercury and methylmercury (r<0.01 for both), suggesting inorganic mercury and methylmercury were possibly more mobile in phloem compared to xylem. PMID:25463705

  7. Determination of methylmercury by electrothermal atomic absorption spectrometry using headspace single-drop microextraction with in situ hydride generation

    International Nuclear Information System (INIS)

    Gil, Sandra; Fragueiro, Sandra; Lavilla, Isela; Bendicho, Carlos

    2005-01-01

    A new method is proposed for preconcentration and matrix separation of methylmercury prior to its determination by electrothermal atomic absorption spectrometry (ETAAS). Generation of methylmercury hydride (MeHgH) from a 5-ml solution is carried out in a closed vial and trapped onto an aqueous single drop (3-μl volume) containing Pd(II) or Pt(IV) (50 and 10 mg/l, respectively). The hydrogen evolved in the headspace (HS) after decomposition of sodium tetrahydroborate (III) injected for hydride generation caused the formation of finely dispersed Pd(0) or Pt(0) in the drop, which in turn, were responsible for the sequestration of MeHgH. A preconcentration factor of ca. 40 is achieved with both noble metals used as trapping agents. The limit of detection of methylmercury was 5 and 4 ng/ml (as Hg) with Pd(II) or Pt(IV) as trapping agents, and the precision expressed as relative standard deviation was about 7%. The preconcentration system was fully characterised through optimisation of the following variables: Pd(II) or Pt(IV) concentration in the drop, extraction time, pH of the medium, temperatures of both sample solution and drop, concentration of salt in the sample solution, sodium tetrahydroborate (III) concentration in the drop and stirring rate. The method has been successfully validated against two fish certified reference materials (CRM 464 tuna fish and CRM DORM-2 dogfish muscle) following selective extraction of methylmercury in 2 mol/l HCl medium

  8. Effects of throughfall and literfall manipulation on concentrations of methylmercury and mercury in forest-floor percolates

    Czech Academy of Sciences Publication Activity Database

    Hojdová, Maria; Huang, J-H.; Kalbitz, K.; Matzner, E.

    2007-01-01

    Roč. 170, č. 3 (2007), s. 373-377 ISSN 1436-8730 R&D Projects: GA AV ČR(CZ) KJB300130615 Institutional research plan: CEZ:AV0Z30130516 Keywords : methylmercury * total mercury * throughfall Subject RIV: DD - Geochemistry Impact factor: 1.082, year: 2007

  9. Influence of Reservoir Water Level Fluctuations on Sediment Methylmercury Concentrations Downstream of the Historical Black Butte Mercury Mine, OR

    Science.gov (United States)

    Mercury (Hg) is a pollutant of global concern due to its ability to accumulate as methylmercury (MeHg) in biota. Mercury is methylated by anaerobic microorganisms such as sulfate reducing bacteria (SRB) in water and sediment. Throughout North America, reservoirs tend to have e...

  10. Tributyltin-resistant Methanothermobacter thermautotrophicus mutant with mutational substitutions in the A.sub.1./sub.A.sub.0./sub.-ATP synthase operon

    Czech Academy of Sciences Publication Activity Database

    Nováková, Z.; Bobálová, Janette; Vidová, M.; Hapala, I.; Šmigáň, P.

    2009-01-01

    Roč. 298, č. 2 (2009), s. 255-259 ISSN 0378-1097 Institutional research plan: CEZ:AV0Z40310501 Keywords : methanoarchaea * bioenergetics * tributyltin resistance Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.199, year: 2009

  11. Transcriptome analyses of sex differential gene expression in brains of rare minnow (Gobiocypris rarus and effects of tributyltin exposure

    Directory of Open Access Journals (Sweden)

    Ji-liang Zhang

    2018-06-01

    Full Text Available RNA-sequencing was used to identify sex-biased gene expression in brains of rare minnow (Gobiocypris rarus by comparing transcriptomic profiles between females and males. Furthermore, transcriptomic responses to 10 ng/L tributyltin (TBT in both male and female brains were also investigated to understand whether TBT affects the identified sex-biased genes. Differentially expressed genes (DEGs were identified using the IDEG6 web tool. In this article, we presented male- and female-biased DEGs, and up-regulated and down-regulated DEGs after TBT exposure. The raw reads data supporting the present analyses has been deposited in NCBI Sequence Read Archive (SRA, http://www.ncbi.nlm.nih.gov/Traces/sra with accession number PRJNA376634. The data presented in this article are related to the research article entitled “Transcriptomic analyses of sexual dimorphism of rare minnow (G. rarus brains and effects of tributyltin exposure” (doi: 10.1016/j.ecoenv.2018.02.049.

  12. Monitoring the degradation capability of novel haloalkaliphilic tributyltin chloride (TBTCl) resistant bacteria from butyltin-polluted site.

    Science.gov (United States)

    Hassan, Hamdy A; Dawah, Somya E; El-Sheekh, Mostafa M

    2018-03-28

    Tributyltin (TBT) is recognized as a major environmental problem at a global scale. Haloalkaliphilic tributyltin (TBT)-degrading bacteria may be a key factor in the remediation of TBT polluted sites. In this work, three haloalkaliphilic bacteria strains were isolated from a TBT-contaminated site in the Mediterranean Sea. After analysis of the 16S rRNA gene sequences the isolates were identified as Sphingobium sp. HS1, Stenotrophomonas chelatiphaga HS2 and Rhizobium borbori HS5. The optimal growth conditions for biodegradation of TBT by the three strains were pH 9 and 7% (w/v) salt concentration. S. chelatiphaga HS2 was the most effective TBT degrader and has the ability to transform most TBT into dibutyltin and monobutyltin (DBT and MBT). A gene was amplified from strain HS2 and identified as TBTB-permease-like, that encodes an ArsB-permease. A reverse transcription polymerase chain reaction analysis in the HS2 strain confirmed that the TBTB-permease-like gene contributes to TBT resistance. The three novel haloalkaliphilic TBT degraders have never been reported previously. Copyright © 2018 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. The effect of tributyltin chloride on Caenorhabditis elegans germline is mediated by a conserved DNA damage checkpoint pathway.

    Science.gov (United States)

    Cheng, Zhe; Tian, Huimin; Chu, Hongran; Wu, Jianjian; Li, Yingying; Wang, Yanhai

    2014-03-21

    Tributyltin (TBT), one of the environmental pollutants, has been shown to impact the reproduction of animals. However, due to the lack of appropriate animal model, analysis of the affected molecular pathways in germ cells is lagging and has been particularly challenging. In the present study, we investigated the effects of tributyltin chloride (TBTCL) on the nematode Caenorhabditis elegans germline. We show that exposure of C. elegans to TBTCL causes significantly elevated level of sterility and embryonic lethality. TBTCL exposure results in an increased number of meiotic DNA double-strand breaks in germ cells, subsequently leading to activated DNA damage checkpoint. Exposing C. elegans to TBTCL causes dose- and time-dependent germline apoptosis. This apoptotic response was blocked in loss-of-function mutants of hus-1 (op241), mrt-2 (e2663) and p53/cep-1 (gk138), indicating that checkpoints and p53 are essential for mediating TBTCL-induced germ cell apoptosis. Moreover, TBTCL exposure can inhibit germ cell proliferation, which is also mediated by the conserved checkpoint pathway. We thereby propose that TBT exhibits its effects on the germline by inducing DNA damage and impaired maintenance of genomic integrity. Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  14. Effects of low dose treatment of tributyltin on the regulation of estrogen receptor functions in MCF-7 cells.

    Science.gov (United States)

    Sharan, Shruti; Nikhil, Kumar; Roy, Partha

    2013-06-01

    Endocrine disrupting chemicals are the natural/synthetic compounds which mimic or inhibit the actions of endogenous hormones. Organotin compounds, such as tributyltin (TBT) are typical environmental contaminants and suspected endocrine-disrupting chemical. The present study evaluates the estrogenic potential of this compound in vitro in ER (+) breast adenocarcinoma, MCF-7 cell line. Our data showed that tributyltin chloride (TBTCl) had agonistic activities for estrogen receptor-α (ER-α). Its estrogenic potential was checked using cell proliferation assay, aromatase assay, transactivation assay, and protein expression analysis. Low dose treatment of TBTCl had a proliferative effect on MCF-7 cells and resulted in up-regulation of aromatase enzyme activity and enhanced estradiol production in MCF-7 cells. Immunofluorescence staining showed translocation of ER-α from cytoplasm to nucleus and increased expression of ER-α, 3β-HSD and aromatase on treatment with increasing doses of TBTCl. Further, to decipher the probable signaling pathways involved in its action, the MCF-7 cells were transfected with different pathway dependent luciferase reporter plasmids (CRE, SRE, NF-κB and AP1). A significant increase in CRE and SRE and decrease in NF-κB regulated pathway were observed (ptributyltin genomically and non-genomically augmented estrogen dependent signaling by targeting various pathways. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Effects of perinatal exposure to low doses of tributyltin chloride on pregnancy outcome and postnatal development in mouse offspring.

    Science.gov (United States)

    Si, Jiliang; Li, Jie; Zhang, Fengmei; Li, Guozhen; Xin, Quanbin; Dai, Bingqin

    2012-10-01

    Tributyltin (TBT), an endocrine-disrupting chemical, is well known to induce imposex in female gastropods. In this study, we assessed the effects of low doses of tributyltin chloride (TBTCl) on dams and their offspring. Pregnant mice were administered by gavage with 0, 1, 10, or 100 μg TBTCl/kg body weight/day from day 6 of pregnancy through the period of lactation. There were no TBT treatment-related deaths or clinical signs of toxicity for dams, and no treatment-related effects on body weight, litter sizes, gestational length of dams, and sex ratio, lactational body weight, postnatal survival, age at eruption of incisors, and eye opening of pups. However, at 100 μg/kg, TBTCl retarded the testes descent of male offspring. Behavioral tests showed a significant delay in cliff-drop aversion response in offspring of 10 and 100 μg/kg groups, but no significant difference in the righting reflex between control and TBT-exposed offspring was detectable. These results indicate that neurobehavioral toxicity seems to be one sensitive indicator to assess the risk of low doses of TBT. Copyright © 2011 Wiley Periodicals, Inc.

  16. The effect of Tributyltin on thyroid follicular cells of adult male albino rats and the possible protective role of green tea: a toxicological, histological and biochemical study.

    Science.gov (United States)

    Badr El Dine, Fatma M M; Nabil, Iman M; Dwedar, Fatma I

    2017-01-01

    Tributyltin is one of the important and wide-spread persistent organic contaminants that accumulate in the food chain. It is suspected to cause endocrine-disrupting effects in mammals, due in part to its possible transfer through marine food chains and to the consumption of contaminated seafood. Was to study the possible toxic effect of Tributyltin on thyroid follicular cells of adult male albino rats and to evaluate the possible protective role of green tea. Forty-five adult male albino rats were included and randomly divided into 3 equal groups: a control group (Group I); Group II: received tributyltin chloride (TBT) dissolved in corn oil orally in a dose of 5 mg/kg for 30 days. Group III: received tributyltin chloride in the same dose with concomitant oral administration of green tea extract for 30 days. At the end of the experiment, the animals were sacrificed and blood samples were subjected to hormonal assay for T3, T4 and TSH levels. Malondialdehyde and reduced glutathione were assessed. The thyroid tissue was processed for histological and ultrastructure examination. The colloid area of thyroid follicles was evaluated morphometrically and statistically analyzed. A significant decrease in T3 and T4 levels and serum reduced glutathione in the group II when compared with the other groups. Furthermore, a significant increase in serum Malondialdehyde and TSH levels was recorded in group II treated group by comparison to the other two groups. Histopathological and ultrastructural changes of thyroid gland follicles were detected in tributyltin treated rats; the follicular cells appeared swollen and vacuolated. Epithelial stratification was noticed in some foci with excessive vacuolation of the colloid. Dilated rough endoplasmic reticulum filled with flocculent material and increased number of lysosomes were also detected together with variation in shape and size of the nuclei. A marked improvement in the histological features of thyroid follicles was noticed in

  17. Influence of intensive fishing on the partitioning of mercury and methylmercury in three lakes of Northern Quebec

    Energy Technology Data Exchange (ETDEWEB)

    Surette, Celine [COMERN, Universite du Quebec a Montreal, c.p. 8888, succ. Centre-Ville, Montreal, Quebec, H3C 3P8 (Canada)]. E-mail: surettc@umoncton.ca; Lucotte, Marc [COMERN, Universite du Quebec a Montreal, c.p. 8888, succ. Centre-Ville, Montreal, Quebec, H3C 3P8 (Canada); Tremblay, A. [Environment Unit, Dams and Environment Direction, Hydro-Quebec Production 75 Rene-Levesque West, 10th floor, Montreal, Quebec, H2Z 1A4 (Canada)

    2006-09-01

    It has been demonstrated that intensive fishing, i.e., removing more than 25% of the fish biomass, can reduce mercury levels in predator fish in a lake. We test here the hypothesis that, by removing an important part of the fish biomass from a lake, a significant amount of methylmercury can be eliminated, therefore reducing the mercury available to the remaining biota, at least in the short term. A mass burden approach is used to evaluate the partitioning of total mercury and methylmercury in natural lake ecosystems. Three small natural lakes from the James Bay territory, in northern Quebec, Canada, were selected for intensive fishing. Mercury (Hg) and methylmercury (MeHg) concentrations were evaluated for sediments, water column (dissolved fraction and suspended particulate matter), plankton, aquatic invertebrates, and fish. Biomasses were determined for fish, plankton, and aquatic invertebrates. Two case scenarios are presented using different mercury contributions from the sediment component (1 cm depth, and no sediment). Our results for the scenario including the sediment contribution show that lake sediments represent over 98% of the total mercury while the biotic components represent less than 0.1% of the same burden. For methylmercury, fish account for up to 5% of the burden, while sediments make up 84.6% to 93.1%. If we put aside the sediment contribution, the methylmercury in fish partitioning can represent up to 48%. As for invertebrates, they can account for up to 48% of the total MeHg burden. We do not observe any change in the partitionings or the quantities of Hg and MeHg before and after fishing in either of the two case scenarios even when we do not take into account dynamics of the ecosystems. This will be all the more the case when the dynamics of the system are included in the analyses. Therefore, biological parameters such as growth rates or fish diet must be considered.

  18. Influence of intensive fishing on the partitioning of mercury and methylmercury in three lakes of Northern Quebec

    International Nuclear Information System (INIS)

    Surette, Celine; Lucotte, Marc; Tremblay, A.

    2006-01-01

    It has been demonstrated that intensive fishing, i.e., removing more than 25% of the fish biomass, can reduce mercury levels in predator fish in a lake. We test here the hypothesis that, by removing an important part of the fish biomass from a lake, a significant amount of methylmercury can be eliminated, therefore reducing the mercury available to the remaining biota, at least in the short term. A mass burden approach is used to evaluate the partitioning of total mercury and methylmercury in natural lake ecosystems. Three small natural lakes from the James Bay territory, in northern Quebec, Canada, were selected for intensive fishing. Mercury (Hg) and methylmercury (MeHg) concentrations were evaluated for sediments, water column (dissolved fraction and suspended particulate matter), plankton, aquatic invertebrates, and fish. Biomasses were determined for fish, plankton, and aquatic invertebrates. Two case scenarios are presented using different mercury contributions from the sediment component (1 cm depth, and no sediment). Our results for the scenario including the sediment contribution show that lake sediments represent over 98% of the total mercury while the biotic components represent less than 0.1% of the same burden. For methylmercury, fish account for up to 5% of the burden, while sediments make up 84.6% to 93.1%. If we put aside the sediment contribution, the methylmercury in fish partitioning can represent up to 48%. As for invertebrates, they can account for up to 48% of the total MeHg burden. We do not observe any change in the partitionings or the quantities of Hg and MeHg before and after fishing in either of the two case scenarios even when we do not take into account dynamics of the ecosystems. This will be all the more the case when the dynamics of the system are included in the analyses. Therefore, biological parameters such as growth rates or fish diet must be considered

  19. Distribution, behavior, and transport of inorganic and methylmercury in a high gradient stream

    International Nuclear Information System (INIS)

    Flanders, J.R.; Turner, R.R.; Morrison, T.; Jensen, R.; Pizzuto, J.; Skalak, K.; Stahl, R.

    2010-01-01

    Research highlights: → Sources of inorganic mercury widespread in high-gradient fluvial system decades after mercury use ceased in watershed. → Soils release more inorganic mercury than sediment, primarily complexed by colloids. → Methylmercury is produced in wide range of habitats despite the high gradient and coarse-grained nature of river. → Methylmercury under complex physical and chemical controls, including temperature, bioavailable mercury, and substrates (carbon and electron acceptors). - Abstract: Concentrations of Hg remain elevated in physical and biological media of the South River (Virginia, USA), despite the cessation of the industrial use of Hg in its watershed nearly six decades ago, and physical characteristics that would not seem to favor Hg(II)-methylation. A 3-a study of inorganic Hg (IHg) and methylmercury (MeHg) was conducted in physical media (soil, sediment, surface water, porewater and soil/sediment extracts) to identify non-point sources, transport mechanisms, and potential controls on Hg(II)-methylation. Data collected from surface water and sediment indicate that the majority of the non-point sources of IHg to the South River are within the first 14 km downstream from the historic point source. Partitioning data indicate that particle bound IHg is introduced in this reach, releasing dissolved and colloidal bound IHg, which is transported downstream. Extraction experiments revealed that floodplain soils released a higher fraction of their IHg content in aqueous extractions than fine-grained sediment (FGS). Based on ultrafiltration [<5000 nominal molecular weight cutoff (NMWC)] the majority of soil IHg released was colloidal in nature, providing evidence for the continued evolution of IHg for Hg(II)-methylation from soil. Strong seasonal patterns in MeHg concentrations were observed in surface water and sediment. The highest concentrations of MeHg in surface water were observed at moderate temperatures, suggesting that other

  20. Wetlands as principal zones of methylmercury production in southern Louisiana and the Gulf of Mexico region

    Energy Technology Data Exchange (ETDEWEB)

    Hall, B.D. [Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, WI 53706 (United States); Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK, S4S 0A2 (Canada)], E-mail: britt.hall@uregina.ca; Aiken, G.R. [United States Geological Survey, 3215 Marine Street, Boulder, CO 80303 (United States); Krabbenhoft, D.P. [United States Geological Survey, 8505 Research Way, Middleton, WI 53562 (United States); Marvin-DiPasquale, M. [United States Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025 (United States); Swarzenski, C.M. [United States Geological Survey, Suite 120, 3535 S. Sherwood Forest Blvd., Baton Rouge, LA 70816 (United States)

    2008-07-15

    It is widely recognized that wetlands, especially those rich in organic matter and receiving appreciable atmospheric mercury (Hg) inputs, are important sites of methylmercury (MeHg) production. Extensive wetlands in the southeastern United States have many ecosystem attributes ideal for promoting high MeHg production rates; however, relatively few mercury cycling studies have been conducted in these environments. We conducted a landscape scale study examining Hg cycling in coastal Louisiana (USA) including four field trips conducted between August 2003 and May 2005. Sites were chosen to represent different ecosystem types, including: a large shallow eutrophic estuarine lake (Lake Pontchartrain), three rivers draining into the lake, a cypress-tupelo dominated freshwater swamp, and six emergent marshes ranging from a freshwater marsh dominated by Panicum hemitomon to a Spartina alterniflora dominated salt marsh close to the Gulf of Mexico. We measured MeHg and total Hg (THg) concentrations, and ancillary chemical characteristics, in whole and filtered surface water, and filtered porewater. Overall, MeHg concentrations were greatest in surface water of freshwater wetlands and lowest in the profundal (non-vegetated) regions of the lake and river mainstems. Concentrations of THg and MeHg in filtered surface water were positively correlated with the highly reactive, aromatic (hydrophobic organic acid) fraction of dissolved organic carbon (DOC). These results suggest that DOC plays an important role in promoting the mobility, transport and bioavailability of inorganic Hg in these environments. Further, elevated porewater concentrations in marine and brackish wetlands suggest coastal wetlands along the Gulf Coast are key sites for MeHg production and may be a principal source of MeHg to foodwebs in the Gulf of Mexico. Examining the relationships among MeHg, THg, and DOC across these multiple landscape types is a first step in evaluating possible links between key zones for

  1. Wetlands as principal zones of methylmercury production in southern Louisiana and the Gulf of Mexico region

    International Nuclear Information System (INIS)

    Hall, B.D.; Aiken, G.R.; Krabbenhoft, D.P.; Marvin-DiPasquale, M.; Swarzenski, C.M.

    2008-01-01

    It is widely recognized that wetlands, especially those rich in organic matter and receiving appreciable atmospheric mercury (Hg) inputs, are important sites of methylmercury (MeHg) production. Extensive wetlands in the southeastern United States have many ecosystem attributes ideal for promoting high MeHg production rates; however, relatively few mercury cycling studies have been conducted in these environments. We conducted a landscape scale study examining Hg cycling in coastal Louisiana (USA) including four field trips conducted between August 2003 and May 2005. Sites were chosen to represent different ecosystem types, including: a large shallow eutrophic estuarine lake (Lake Pontchartrain), three rivers draining into the lake, a cypress-tupelo dominated freshwater swamp, and six emergent marshes ranging from a freshwater marsh dominated by Panicum hemitomon to a Spartina alterniflora dominated salt marsh close to the Gulf of Mexico. We measured MeHg and total Hg (THg) concentrations, and ancillary chemical characteristics, in whole and filtered surface water, and filtered porewater. Overall, MeHg concentrations were greatest in surface water of freshwater wetlands and lowest in the profundal (non-vegetated) regions of the lake and river mainstems. Concentrations of THg and MeHg in filtered surface water were positively correlated with the highly reactive, aromatic (hydrophobic organic acid) fraction of dissolved organic carbon (DOC). These results suggest that DOC plays an important role in promoting the mobility, transport and bioavailability of inorganic Hg in these environments. Further, elevated porewater concentrations in marine and brackish wetlands suggest coastal wetlands along the Gulf Coast are key sites for MeHg production and may be a principal source of MeHg to foodwebs in the Gulf of Mexico. Examining the relationships among MeHg, THg, and DOC across these multiple landscape types is a first step in evaluating possible links between key zones for

  2. Distribution, behavior, and transport of inorganic and methylmercury in a high gradient stream

    Energy Technology Data Exchange (ETDEWEB)

    Flanders, J.R., E-mail: john_flanders@urscorp.com [URS Corporation, 335 Commerce Drive, Suite 300, Fort Washington, PA 19034 (United States); Turner, R.R. [RTGeosciences Inc., PO Box 421, Squamish, BC (Canada); Morrison, T. [URS Corporation, 335 Commerce Drive, Suite 300, Fort Washington, PA 19034 (United States); Jensen, R. [Unique Environmental Services, 5406 Crestline Rd., Wilmington, DE 19808 (United States); Pizzuto, J. [University of Delaware, Department of Geology, 101D Penny Hall, Newark, DE 19716 (United States); Skalak, K. [US Geological Survey, 430 National Center, Reston, VA 20192 (United States); Stahl, R. [DuPont Corporate Remediation Group, 1447 Lancaster Pike, Wilmington, DE (United States)

    2010-11-15

    Research highlights: {yields} Sources of inorganic mercury widespread in high-gradient fluvial system decades after mercury use ceased in watershed. {yields} Soils release more inorganic mercury than sediment, primarily complexed by colloids. {yields} Methylmercury is produced in wide range of habitats despite the high gradient and coarse-grained nature of river. {yields} Methylmercury under complex physical and chemical controls, including temperature, bioavailable mercury, and substrates (carbon and electron acceptors). - Abstract: Concentrations of Hg remain elevated in physical and biological media of the South River (Virginia, USA), despite the cessation of the industrial use of Hg in its watershed nearly six decades ago, and physical characteristics that would not seem to favor Hg(II)-methylation. A 3-a study of inorganic Hg (IHg) and methylmercury (MeHg) was conducted in physical media (soil, sediment, surface water, porewater and soil/sediment extracts) to identify non-point sources, transport mechanisms, and potential controls on Hg(II)-methylation. Data collected from surface water and sediment indicate that the majority of the non-point sources of IHg to the South River are within the first 14 km downstream from the historic point source. Partitioning data indicate that particle bound IHg is introduced in this reach, releasing dissolved and colloidal bound IHg, which is transported downstream. Extraction experiments revealed that floodplain soils released a higher fraction of their IHg content in aqueous extractions than fine-grained sediment (FGS). Based on ultrafiltration [<5000 nominal molecular weight cutoff (NMWC)] the majority of soil IHg released was colloidal in nature, providing evidence for the continued evolution of IHg for Hg(II)-methylation from soil. Strong seasonal patterns in MeHg concentrations were observed in surface water and sediment. The highest concentrations of MeHg in surface water were observed at moderate temperatures

  3. Tributyltin: Advancing the science on assessing endocrine disruption with an unconventional endocrine-disrupting compound

    Science.gov (United States)

    Lagadic, Laurent; Katsiadaki, Ioanna; Biever, Ronald C.; Guiney, Patrick; Karouna-Renier, Natalie; Schwarz, Tamar; Meador, James P.

    2018-01-01

    Tributyltin (TBT) has been recognized as an endocrine disrupting chemical (EDC) for several decades. However, only in the last decade, was its primary endocrine mechanism of action (MeOA) elucidated—interactions with the nuclear retinoid-X receptor (RXR), peroxisome proliferator-activated receptor γ (PPARγ), and their heterodimers. This molecular initiating event (MIE) alters a range of reproductive, developmental, and metabolic pathways at the organism level. It is noteworthy that a variety of MeOAs have been proposed over the years for the observed endocrine-type effects of TBT; however, convincing data for the MIE was provided only recently and now several researchers have confirmed and refined the information on this MeOA. One of the most important lessons learned from years of research on TBT concerns apparent species sensitivity. Several aspects such as the rates of uptake and elimination, chemical potency, and metabolic capacity are all important for identifying the most sensitive species for a given chemical, including EDCs. For TBT, much of this was discovered by trial and error, hence important relationships and important sensitive taxa were not identified until several decades after its introduction to the environment. As recognized for many years, TBT-induced responses are known to occur at very low concentrations for molluscs, a fact that has more recently also been observed in fish species. This review explores the MeOA and effects of TBT in different species (aquatic molluscs and other invertebrates, fish, amphibians, birds, and mammals) according to the OECD Conceptual Framework for Endocrine Disruptor Testing and Assessment (CFEDTA). The information gathered on biological effects that are relevant for populations of aquatic animals was used to construct Species Sensitivity Distributions (SSDs) based on No Observed Effect Concentrations (NOECs) and Lowest Observed Effect Concentrations (LOECs). Fish appear at the lower end of these distributions

  4. Tributyltin impaired reproductive success in female zebrafish through disrupting oogenesis, reproductive behaviors and serotonin synthesis.

    Science.gov (United States)

    Xiao, Wei-Yang; Li, Ying-Wen; Chen, Qi-Liang; Liu, Zhi-Hao

    2018-07-01

    Tributyltin (TBT), an organotin acting as aromatase (Cyp19a1) inhibitor, has been found to disrupt gametogenesis and reproductive behaviors in several fish species. However, few studies addressing the mechanisms underlying the impaired gametogenesis and reproduction have been reported. In this study, female adults of zebrafish (Danio rerio) were continuously exposed to two nominal concentrations of TBT (100 and 500 ng/L, actual concentrations: 90.8 ± 1.3 ng/L and 470.3 ± 2.7 ng/L, respectively) for 28 days. After exposures, TBT decreased the total egg number, reduced the hatchability and elevated the mortality of the larvae. Decreased gonadosomatic index (GSI) and altered percentages of follicles in different developmental stages (increased early-stage follicles and reduced mid/late-stage follicles) were also observed in the ovary of TBT-treated fish. TBT also lowered the plasma level of 17β-estradiol and suppressed the expressions of cyp19a1a in the ovary. In treated fish, up-regulated expressions of aldhla2, sycp3 and dmc1 were present in the ovary, indicating an enhanced level of meiosis. The mRNA level of vtg1 was dramatically suppressed in the liver of TBT-treated fish, suggesting an insufficient synthesis of Vtg protein, consistent with the decreased percentage of mid/late-stage follicles in the ovaries. Moreover, TBT significantly suppressed the reproductive behaviors of the female fish (duration of both sexes simultaneously in spawning area, the frequency of meeting and the visit in spawning area) and down-regulated the mRNA levels of genes involved in the regulation of reproductive behaviors (cyp19a1b, gnrh-3 and kiss 2) in the brain. In addition, TBT significantly suppressed the expressions of serotonin-related genes, such as tph2 (encoding serotonin synthase), pet1 (marker of serotonin neuron) and kiss 1 (the modulator of serotonin synthesis), suggesting that TBT might disrupt the non-reproductive behaviors of zebrafish. The present

  5. Toxic effects of tributyltin and its metabolites on harbour seal (Phoca vitulina) immune cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Frouin, Heloise [Institut National de la Recherche Scientifique - Institut Armand-Frappier, Laval, Quebec H7V 1B7 (Canada); Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, Quebec G5H 3Z4 (Canada)], E-mail: heloise.frouin@iaf.inrs.ca; Lebeuf, Michel [Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, Quebec G5H 3Z4 (Canada); Saint-Louis, Richard [Institut des Sciences de la Mer de Rimouski (ISMER), Universite du Quebec a Rimouski, Rimouski, Quebec G5L 3A1 (Canada); Hammill, Mike [Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, Quebec G5H 3Z4 (Canada); Pelletier, Emilien [Institut des Sciences de la Mer de Rimouski (ISMER), Universite du Quebec a Rimouski, Rimouski, Quebec G5L 3A1 (Canada); Fournier, Michel [Institut National de la Recherche Scientifique - Institut Armand-Frappier, Laval, Quebec H7V 1B7 (Canada)

    2008-11-21

    The widespread environmental contamination, bioaccumulation and endocrine disruptor effects of butyltins (BTs) to wildlife are well documented. Although suspected, potential effects of BTs exposure on the immune system of marine mammals have been little investigated. In this study, we assessed the effects of tributyltin (TBT) and its dealkylated metabolites dibutyltin (DBT) and monobutyltin (MBT) on the immune responses of harbour seals. Peripheral blood mononuclear cells isolated from pup and adult harbour seals were exposed in vitro to varying concentrations of BTs. DBT resulted in a significant decrease at 100 and 200 nM of phagocytotic activity and reduced significantly phagocytic efficiency at 200 nM in adult seals. There was no effect in phagocytosis with TBT and MBT. In pups, the highest concentration (200 nM) of DBT inhibited phagocytic efficiency. A reduction of tumor-killing capacity of adult natural killer (NK) cells occurred when leukocytes were incubated in vitro with 50 nM DBT and 200 nM TBT for 24 h. In adult seals, T-lymphocyte proliferation was significantly suppressed when the cells were exposed to 200 nM TBT and 100 nM DBT. In pups, the proliferative response increased after an exposure to 100 nM TBT and 50 nM DBT, but decreased with 200 nM TBT and 100 nM DBT. The immune functions were more affected by BTs exposure in adults than in pups, suggesting that other unsuspected mechanisms could trigger immune parameters in pups. The toxic potential of BTs followed the order of DBT > TBT > MBT. BT concentrations of harbour seal pups from the St. Lawrence Estuary (Bic National Park) ranged between 0.1-0.4 ng Sn/g wet weight (ww) and 1.2-13.4 ng Sn/g ww in blood and blubber, respectively. For these animals, DBT concentrations were consistently below the quantification limit of 0.04 ng Sn/g ww in blood and 0.2 ng Sn/g ww in blubber. Results suggest that concentrations measured in pups are considered too low to induce toxic effects to their immune system

  6. A Short-Term Exposure to Tributyltin Blocks Leydig Cell Regeneration in the Adult Rat Testis

    Directory of Open Access Journals (Sweden)

    Xiaolong Wu

    2017-10-01

    Full Text Available Background: Tributyltin (TBT is widely used as an antifouling agent that may cause reproductive toxicity. The mechanism of TBT on Leydig cell development is still unknown. The objective of the present study was to investigate whether a brief exposure to low doses of TBT permanently affects Leydig cell development and to clarify the underlying mechanism.Methods: Adult male Sprague Dawley rats were randomly assigned into four groups and gavaged normal saline (control, 0.1, 1.0, or 10.0 mg/kg/day TBT for a consecutive 10 days, respectively. At the end of TBT treatment, all rats received a single intraperitoneal injection of 75 mg/kg ethane dimethane sulfonate (EDS to eliminate all of adult Leydig cells. Leydig cells began a developmental regeneration process on post-EDS day 35. The Leydig cell regeneration was evaluated by measuring serum testosterone, luteinizing hormone, and follicle-stimulating hormone levels on post-EDS day 7, 35, and 56, the expression levels of Leydig cell genes, Leydig cell morphology and number and proliferation on post-EDS day 56.Results: TBT significantly reduced serum testosterone levels on post-EDS day 35 and 56 and increased serum luteinizing hormone and follicle-stimulating hormone levels on post-EDS day 56 at ≥1 mg/kg/day. Immunohistochemical staining showed that there were fewer regenerated Leydig cells in the TBT-treated testis on post-EDS day 56. Further study demonstrated that the mRNA or protein levels of Leydig (Lhcgr, Cyp11a1, Hsd3b1, Cyp17a1, and Hsd17b3 and Sertoli cells (Fshr, Dhh, and Sox9 were significantly down-regulated in the TBT-treated testes when compared to the control. Immunofluorescent staining showed that TBT inhibited Leydig cell proliferation as judged by the reduced number of proliferating cyclin nuclear antigen-positive Leydig cells on post-EDS day 35.Conclusion: The present study demonstrated that a short-term TBT exposure blocked Leydig cell developmental regeneration process via down

  7. Fifteen years of imposex and tributyltin pollution monitoring along the Portuguese coast.

    Science.gov (United States)

    Laranjeiro, Filipe; Sánchez-Marín, Paula; Oliveira, Isabel Benta; Galante-Oliveira, Susana; Barroso, Carlos

    2018-01-01

    IMO's Anti-Fouling Systems convention banned the use of organotin-based antifouling systems in 2008 as the ultimate effort to stop tributyltin (TBT) inputs into the marine environment. One of the hazardous effects of TBT is imposex (the superimposition of male sexual characters onto gastropod females), a phenomenon that may cause female sterility and the gastropod populations decline. Despite previous European Union legislation had already been shown effective in reducing the imposex levels along the Portuguese coast, this study intends to confirm these decreasing trends after 2008 and describe the global evolution in the last 15 years. Imposex levels were assessed in two bioindicators - the dog-whelk Nucella lapillus and the netted-whelk Nassarius reticulatus (Gastropoda, Prosobranchia) - in 2011 and 2014, and the results were compared with previous years. Both species showed progressive decreasing trends in imposex levels over the last 15 years; median values of the vas deferens sequence index (VDSI) fell from 3.96 to 0.78 in N. lapillus and from 3.39 to 0.29 in N. reticulatus. The temporal/spatial evolution of imposex suggests an apparent shift of TBT hotspots, being now restricted to fishing ports and marinas in detriment of large commercial harbours where TBT levels fell rapidly. Butyltins were measured in the whole tissues of N. lapillus females collected in 2014: monobutyltin (MBT) varied from < DL (detection limit: 1 ng Sn/g) to 13 ng Sn/g dw, dibutyltin (DBT) from 2.2 to 27 ng Sn/g dw and TBT from 1.5 to 55 ng Sn/g dw. Although TBT body burden has declined over time, the butyltin degradation index ([MBT]+[DBT])/[TBT] exhibited values < 1 in c. a. 90% of the sites assessed, suggesting that recent TBT inputs are still widespread in the Portuguese coast eventually due to illegal use of TBT antifouling systems and TBT desorption from sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Toxic effects of tributyltin and its metabolites on harbour seal (Phoca vitulina) immune cells in vitro

    International Nuclear Information System (INIS)

    Frouin, Heloise; Lebeuf, Michel; Saint-Louis, Richard; Hammill, Mike; Pelletier, Emilien; Fournier, Michel

    2008-01-01

    The widespread environmental contamination, bioaccumulation and endocrine disruptor effects of butyltins (BTs) to wildlife are well documented. Although suspected, potential effects of BTs exposure on the immune system of marine mammals have been little investigated. In this study, we assessed the effects of tributyltin (TBT) and its dealkylated metabolites dibutyltin (DBT) and monobutyltin (MBT) on the immune responses of harbour seals. Peripheral blood mononuclear cells isolated from pup and adult harbour seals were exposed in vitro to varying concentrations of BTs. DBT resulted in a significant decrease at 100 and 200 nM of phagocytotic activity and reduced significantly phagocytic efficiency at 200 nM in adult seals. There was no effect in phagocytosis with TBT and MBT. In pups, the highest concentration (200 nM) of DBT inhibited phagocytic efficiency. A reduction of tumor-killing capacity of adult natural killer (NK) cells occurred when leukocytes were incubated in vitro with 50 nM DBT and 200 nM TBT for 24 h. In adult seals, T-lymphocyte proliferation was significantly suppressed when the cells were exposed to 200 nM TBT and 100 nM DBT. In pups, the proliferative response increased after an exposure to 100 nM TBT and 50 nM DBT, but decreased with 200 nM TBT and 100 nM DBT. The immune functions were more affected by BTs exposure in adults than in pups, suggesting that other unsuspected mechanisms could trigger immune parameters in pups. The toxic potential of BTs followed the order of DBT > TBT > MBT. BT concentrations of harbour seal pups from the St. Lawrence Estuary (Bic National Park) ranged between 0.1-0.4 ng Sn/g wet weight (ww) and 1.2-13.4 ng Sn/g ww in blood and blubber, respectively. For these animals, DBT concentrations were consistently below the quantification limit of 0.04 ng Sn/g ww in blood and 0.2 ng Sn/g ww in blubber. Results suggest that concentrations measured in pups are considered too low to induce toxic effects to their immune system

  9. Effects of tributyltin (TBT) on in vitro hormonal and biotransformation responses in Atlantic salmon (Salmo salar).

    Science.gov (United States)

    Mortensen, Anne S; Arukwe, Augustine

    2009-01-01

    The mechanisms by which the biocide tributyltin (TBT) and its metabolites affect the hormonal and xenobiotic biotransformation pathways in aquatic species are not well understood. In this study hepatocytes isolated from salmon were used to evaluate the mechanistical effects of TBT on fish hormonal and xenobiotic biotransformation pathways. Cells were exposed to 0.01, 0.1, 1, or 5 microM TBT and samples were collected at 0, 12, 24, or 48 h following exposure. Gene expression patterns were evaluated using quantitative polymerase chain reaction (PCR), and cytochrome P-450 (CYP)-mediated enzyme activities were evaluated by ethoxyresorufin, benzyloxyresorufin, and pentoxyresorufin O-deethylase (EROD, BROD, and PROD, respectively) activity assays. Generally, exposure of hepatocytes to 1 microM (at 48 h) and 5 microM TBT (at 12, 24, and 48 h) consistently produced reductions in all mRNA species investigated. TBT produced significant decreases of vitellogen (Vtg) expression at 48 h and modified the expression patterns of estrogen receptors (ERalpha and ERbeta) and androgen receptor-beta (ARbeta) that were dependent on time and TBT concentration. In the xenobiotic biotransformation pathway, TBT produced differential expression patterns that were dependent on exposure time and concentration for all salmonid AhR2 isoforms (AhR2alpha, AhR2beta, AhR2delta, and AhR2gamma). For CYP1A1, CYP3A, AhRR, and Arnt mRNA, TBT produced exposure- and time-specific modulations. Catalytic CYP activities showed that BROD activity increased in an apparent concentration-specific manner in cells exposed to TBT for 12 h. Interestingly, EROD activity showed a TBT concentration-dependent increase at 24 h and PROD at 12 and 48 h of exposure. In general our data show that TBT differentially modulated hormonal and biotransformation responses in the salmon in vitro system. The apparent and consistent decrease of the studied responses with time in 1 and 5 microM exposed hepatocytes suggest a possible

  10. Tributyltin: Advancing the Science on Assessing Endocrine Disruption with an Unconventional Endocrine-Disrupting Compound.

    Science.gov (United States)

    Lagadic, Laurent; Katsiadaki, Ioanna; Biever, Ron; Guiney, Patrick D; Karouna-Renier, Natalie; Schwarz, Tamar; Meador, James P

    Tributyltin (TBT) has been recognized as an endocrine disrupting chemical (EDC) for several decades. However, only in the last decade, was its primary endocrine mechanism of action (MeOA) elucidated-interactions with the nuclear retinoid-X receptor (RXR), peroxisome proliferator-activated receptor γ (PPARγ), and their heterodimers. This molecular initiating event (MIE) alters a range of reproductive, developmental, and metabolic pathways at the organism level. It is noteworthy that a variety of MeOAs have been proposed over the years for the observed endocrine-type effects of TBT; however, convincing data for the MIE was provided only recently and now several researchers have confirmed and refined the information on this MeOA. One of the most important lessons learned from years of research on TBT concerns apparent species sensitivity. Several aspects such as the rates of uptake and elimination, chemical potency, and metabolic capacity are all important for identifying the most sensitive species for a given chemical, including EDCs. For TBT, much of this was discovered by trial and error, hence important relationships and important sensitive taxa were not identified until several decades after its introduction to the environment. As recognized for many years, TBT-induced responses are known to occur at very low concentrations for molluscs, a fact that has more recently also been observed in fish species. This review explores the MeOA and effects of TBT in different species (aquatic molluscs and other invertebrates, fish, amphibians, birds, and mammals) according to the OECD Conceptual Framework for Endocrine Disruptor Testing and Assessment (CFEDTA). The information gathered on biological effects that are relevant for populations of aquatic animals was used to construct Species Sensitivity Distributions (SSDs) based on No Observed Effect Concentrations (NOECs) and Lowest Observed Effect Concentrations (LOECs). Fish appear at the lower end of these distributions

  11. Tributyltin chloride disrupts aortic vascular reactivity and increases reactive oxygen species production in female rats.

    Science.gov (United States)

    Ximenes, Carolina Falcão; Rodrigues, Samya Mere Lima; Podratz, Priscila Lang; Merlo, Eduardo; de Araújo, Julia Fernandez Puñal; Rodrigues, Lívia Carla Melo; Coitinho, Juliana Barbosa; Vassallo, Dalton Valentim; Graceli, Jones Bernardes; Stefanon, Ivanita

    2017-11-01

    Organotin compounds, such as tributyltin (TBT), are environment contaminants that induce bioaccumulation and have potential toxic effects on marine species and mammals. TBT have been banned by the International Maritime Organization in 2003. However, the assessment of butyltin and metal contents in marine sediments has demonstrated high residual levels of TBT in some cases exceeding 7000 ng Sn g -1 . The acceptable daily intake (ADI) level for TBT established by the World Health Organization is 0.5 μg/kg bw/day is based on genotoxicity, reproduction, teratogenicity, immunotoxicity, and mainly neurotoxicity. However, their effect on the cardiovascular system is not well understood. In this study, female rats were exposed to 0.5 μg/kg/day of TBT for 15 days with the goal of understanding the effect of TBT on vascular function. Female Wistar rats were treated daily by gavage and divided into control (n = 10) and TBT (n = 10) groups. The aortic rings were incubated with phenylephrine in both the presence and absence of endothelium. The phenylephrine concentration-response curves were generated by exposing endothelium-intact samples to N G -nitro-L-arginine methyl ester (L-NAME), apocynin, superoxide dismutase (SOD), catalase, tiron, and allopurinol. Acetylcholine (ACh) and sodium nitroprusside (SNP) were used to evaluate the relaxation response. Exposure to TBT reduced serum 17β-estradiol E 2 levels and increased vascular reactivity. After incubation with L-NAME, the vascular reactivity to phenylephrine was significantly higher. Apocynin, SOD, catalase, and tiron decreased the vascular reactivity to phenylephrine to a significantly greater extent in TBT-treated rats than in the control rat. The relaxation induced by ACh and SNP was significantly reduced in TBT rats. Exposure to TBT induced aortic wall atrophy and increased superoxide anion production and collagen deposition. These results provide evidence that exposing rats to the current ADI for TBT (0.5

  12. A Short-Term Exposure to Tributyltin Blocks Leydig Cell Regeneration in the Adult Rat Testis.

    Science.gov (United States)

    Wu, Xiaolong; Liu, Jianpeng; Duan, Yue; Gao, Shiyu; Lü, Yao; Li, Xiaoheng; Zhu, Qiqi; Chen, Xianwu; Lin, Jing; Ye, Leping; Ge, Ren-Shan

    2017-01-01

    Background: Tributyltin (TBT) is widely used as an antifouling agent that may cause reproductive toxicity. The mechanism of TBT on Leydig cell development is still unknown. The objective of the present study was to investigate whether a brief exposure to low doses of TBT permanently affects Leydig cell development and to clarify the underlying mechanism. Methods: Adult male Sprague Dawley rats were randomly assigned into four groups and gavaged normal saline (control), 0.1, 1.0, or 10.0 mg/kg/day TBT for a consecutive 10 days, respectively. At the end of TBT treatment, all rats received a single intraperitoneal injection of 75 mg/kg ethane dimethane sulfonate (EDS) to eliminate all of adult Leydig cells. Leydig cells began a developmental regeneration process on post-EDS day 35. The Leydig cell regeneration was evaluated by measuring serum testosterone, luteinizing hormone, and follicle-stimulating hormone levels on post-EDS day 7, 35, and 56, the expression levels of Leydig cell genes, Leydig cell morphology and number and proliferation on post-EDS day 56. Results: TBT significantly reduced serum testosterone levels on post-EDS day 35 and 56 and increased serum luteinizing hormone and follicle-stimulating hormone levels on post-EDS day 56 at ≥1 mg/kg/day. Immunohistochemical staining showed that there were fewer regenerated Leydig cells in the TBT-treated testis on post-EDS day 56. Further study demonstrated that the mRNA or protein levels of Leydig ( Lhcgr , Cyp11a1, Hsd3b1, Cyp17a1 , and Hsd17b3 ) and Sertoli cells ( Fshr , Dhh , and Sox9 ) were significantly down-regulated in the TBT-treated testes when compared to the control. Immunofluorescent staining showed that TBT inhibited Leydig cell proliferation as judged by the reduced number of proliferating cyclin nuclear antigen-positive Leydig cells on post-EDS day 35. Conclusion: The present study demonstrated that a short-term TBT exposure blocked Leydig cell developmental regeneration process via down

  13. Toxic effects of tributyltin and its metabolites on harbour seal (Phoca vitulina) immune cells in vitro.

    Science.gov (United States)

    Frouin, Héloïse; Lebeuf, Michel; Saint-Louis, Richard; Hammill, Mike; Pelletier, Emilien; Fournier, Michel

    2008-11-21

    The widespread environmental contamination, bioaccumulation and endocrine disruptor effects of butyltins (BTs) to wildlife are well documented. Although suspected, potential effects of BTs exposure on the immune system of marine mammals have been little investigated. In this study, we assessed the effects of tributyltin (TBT) and its dealkylated metabolites dibutyltin (DBT) and monobutyltin (MBT) on the immune responses of harbour seals. Peripheral blood mononuclear cells isolated from pup and adult harbour seals were exposed in vitro to varying concentrations of BTs. DBT resulted in a significant decrease at 100 and 200 nM of phagocytotic activity and reduced significantly phagocytic efficiency at 200 nM in adult seals. There was no effect in phagocytosis with TBT and MBT. In pups, the highest concentration (200 nM) of DBT inhibited phagocytic efficiency. A reduction of tumor-killing capacity of adult natural killer (NK) cells occurred when leukocytes were incubated in vitro with 50 nM DBT and 200 nM TBT for 24h. In adult seals, T-lymphocyte proliferation was significantly suppressed when the cells were exposed to 200 nM TBT and 100 nM DBT. In pups, the proliferative response increased after an exposure to 100 nM TBT and 50 nM DBT, but decreased with 200 nM TBT and 100 nM DBT. The immune functions were more affected by BTs exposure in adults than in pups, suggesting that other unsuspected mechanisms could trigger immune parameters in pups. The toxic potential of BTs followed the order of DBT>TBT>MBT. BT concentrations of harbour seal pups from the St. Lawrence Estuary (Bic National Park) ranged between 0.1-0.4 ng Sn/g wet weight (ww) and 1.2-13.4 ng Sn/g ww in blood and blubber, respectively. For these animals, DBT concentrations were consistently below the quantification limit of 0.04 ng Sn/g ww in blood and 0.2 ng Sn/g ww in blubber. Results suggest that concentrations measured in pups are considered too low to induce toxic effects to their immune system during

  14. Tributyltin or triphenyltin inhibits aromatase activity in the human granulosa-like tumor cell line KGN.

    Science.gov (United States)

    Saitoh, M; Yanase, T; Morinaga, H; Tanabe, M; Mu, Y M; Nishi, Y; Nomura, M; Okabe, T; Goto, K; Takayanagi, R; Nawata, H

    2001-11-23

    The superimposition of male sex organs (penis and vas deferens) in a female gastropod, called imposex, is widely attributed to the exposure to tributyltin (TBT) compounds, used world-wide in antifouling paints for ships. It has been hypothesized that the TBT-induced imposex is mediated by an increasing androgen level relative to the estrogen level, namely a decreased conversion of androgens to estrogens (i.e., aromatization). In the present study, we tested this hypothesis by examining the effects of TBT or triphenyltin (TPT) on the aromatase activity in a cultured human granulosa-like tumor cell line, KGN, which was recently established by our group. Treatment with more than 1000 ng/ml TBT compounds was very toxic to the cells and caused immediate cell death within 24 h, while 200 ng/ml was found to cause apoptosis of the cells. Treatment of the KGN cells for more than 48 h with 20 ng/ml TBT or TPT, which is a concentration level reported to cause imposex in marine species, did not affect cell proliferation but significantly suppressed the aromatase activity determined by a [(3)H]H(2)O release assay. Treatment with 20 ng/ml TBT compounds for 7 days also resulted in a reduction of the E2 production from Delta 4-androstenedione stimulated by db-cAMP. The changes in the aromatase activity by TBT compounds were associated with comparable changes in P450arom mRNA assessed by RT-PCR. The luciferase activity of the P450arom promoter II (1 kb) decreased after the addition of 20 ng/ml TBT compounds in transfected KGN cells either in a basic state or in states stimulated by db-cAMP. The Ad4BP-dependent increase in the luciferase activity of P450arom promoter II was also downregulated by such treatments. These results indicate that TBT compounds inhibited the aromatase activity and also decreased the P450arom mRNA level at the transcriptional level in KGN cells. The direct inhibitory effect of TBT compounds on the aromatase activity may therefore partly explain the induction

  15. Life-cycle toxicity of bis(tributyltin) oxide to the sheepshead minnow (Cyprinodon variegatus).

    Science.gov (United States)

    Manning, C S; Lytle, T F; Walker, W W; Lytle, J S

    1999-08-01

    The effects of tributyltin (TBT) to the life cycle of the estuarine fish Cyprinodon variegatus were examined in a 180-day flow-through exposure. The study was initiated with embryos less than 24 h postfertilization and monitored through hatch, maturation, growth, and reproduction under continuous exposure to mean measured TBT concentrations of 5.4, 3.2, 1.3, 0.66, and 0.41 microg TBT/L. Progeny isolated at the onset of reproduction by the parental generation (F0) were monitored for survival as embryos, survival as fry/juveniles, and growth 30 days postisolation. TBT, at a concentration of 5.4 microg/L, significantly reduced embryo survival of the F0 generation sheepshead minnows. By day 145 of the exposure, significant effects to the survival of this generation increased and included all test concentrations >/=0.66 microg/L. Survival of 0.66 microg/L was reduced 59% relative to control survival by termination of the F0 generation. Growth of F0 generation organisms as measured by standard length was significantly reduced only on day 90 at 3.2 microg/L, however no significant reductions of wet or dry weight related to treatment concentration were detected. Due to complete mortality of organisms exposed to 5.4 microg/L by study day 7, effects to fecundity and progeny were monitored at measured concentrations of 3.2, 1.3, 0.66, and 0.41 microg TBT/L. Fecundity, as measured by the production of viable eggs produced per female per day, was unaffected by any of the test treatments. All F1 generation embryos isolated from treatment chambers into 3.2 microg/L died. Survival, standard length, wet and dry weight of the F1 generation at the remaining treatment concentrations were unaffected. The results of this study indicate that exposure to TBT reduced survival of the F0 generation sheepshead minnow and establishes the lowest observed effect concentration (LOEC) as 0.66 microg TBT/L, and the no observed effect concentration (NOEC) as 0.41 microg TBT/L for this species

  16. Acute toxic responses of the freshwater planarian, Dugesia dorotocephala, to methylmercury

    Energy Technology Data Exchange (ETDEWEB)

    Best, J.B.; Morita, M.; Ragin, J.; Best, J. Jr.

    1981-07-01

    Toxic responses of planaria to various aquatic habitat concentrations of methylmercury chloride (MMC) were investigated. One hundred percent lethality occurred within 5 h in 2 ppM MMC, 24 h in 1 ppM MMC, and 5 days in 0.5 ppM MMC. No deaths occurred in 0.2 ppM MMC over a 10 day period, however, non-lethal toxic responses were observed. Varying degrees of head resorption, progressing caudally from the snout were observed. With continuing exposure, partial head regeneration and recovery toward more normal appearance occurred by 10 days. Teratogenic effects were observed in surgical decapitation experiments. Head regeneration was retarded in 0.1 and 0.2 ppM MMC. Malformations, visible lesions, or gross behavioral abnormalities were produced by 2 week exposure of planaria to concentrations of 20 ppB MMC or lower. (RJC)

  17. Methylmercury in the Gulf of Trieste (Northern Adriatic Sea: From Microbial Sources to Seafood Consumers

    Directory of Open Access Journals (Sweden)

    Mark E. Hines

    2014-01-01

    Full Text Available The Gulf of Trieste (northern Adriatic Sea is one of the most mercury-polluted areas in the Mediterranean and in the world due to the past mining activity in the Idrija region (western Slovenia. The link between microbial production of toxic methylmercury (MeHg, and its bioaccumulation and biomagnification in marine food webs of the gulf is at present rather poorly characterized but is critical to understanding the links between sources and higher trophic levels, such as fish, that are ultimately vectors of human and wildlife exposure. This overview explores three major topics: (i the microbial biogeochemical cycling of Hg in the area, (ii the trophic transfer and bioaccumulation of MeHg in pelagic and benthic marine food webs, and (iii human exposure to Hg through marine fish and shellfish consumption. These are important goals since the Gulf of Trieste is an area of great economical importance.

  18. The effects of methylmercury on the mitochondrial energetics of rat skeletal muscle

    International Nuclear Information System (INIS)

    Kuwabara, Takeo; Yuasa, Tatsuhiko; Nagashima, Masaru; Igarashi, Hironaka; Yonemochi, Yousuke; Atsumi, Tetsushi; Miyatake, Tadashi

    1989-01-01

    In this report it is shown that methylmercury chloride (MMC) affected the mitochondrial energetics of rat skeletal muscles in case of chronic intoxication. High energy phosphate compounds were measured by 31 P-NMR spectroscopy in the living rat hindleg skeletal muscle. Decreased value of phosphocreatine (PCr)/inorganic phosphate (Pi) ratio was observed in the resting muscle of the MMC intoxicated group, and suspend recovery of the ATP, PCr and intracellular pH after muscle contraction was found in the MMC intoxicated muscle. There was no difference in the ATP levels of the resting muscle between the control and MMC group. These results suggested that the synthesis of ATP was disturbed by the inhibition of mitochondrial respiration below TCA cycle. (author)

  19. Determination of mercury and methylmercury in Vietnamese pregnant woman head hair

    International Nuclear Information System (INIS)

    Nguyen Tac Anh; Ho Manh Dung; Le Tat Mua; Vu Tien Ha

    1992-01-01

    As a participant to the Coordinated Research Program (CRP) on the Assessment of Environmental Exposure to Mercury in Selected Human Populations as Studied by Nuclear and Other Techniques since 1 July 1992, the Vietnamese started to carry out work on project ''Determination of Mercury and Methylmercury in Vietnamese Pregnant Women Head Hair''. This study is aimed at making a concrete survey of hair mercury levels in groups of women as monitored continuously from early pregnancy to post-natal period. The obtained data could be of great usefulness for further investigation on potential health risks in pregnant women and their babies as related to degree of mercury pollution in the environment. 2 figs, 7 tabs

  20. Secondary sex ratio in relation to exposures to polychlorinated biphenyls, dichlorodiphenyl dichloroethylene and methylmercury

    DEFF Research Database (Denmark)

    Timmermann, Clara Amalie Gade; Choi, Anna L.; Petersen, Maria Skaalum

    2017-01-01

    This study was undertaken to assess the potential impact of maternal exposures to polychlorinated biphenyl (PCB), dichlorodiphenyl dichloroethylene (DDE) and methylmercury on the secondary sex ratios (the ratio of male to female live births) over a span of 23 years. The study includes prospective...... data from three Faroese birth cohorts, with a total of 2,152 healthy mother-child dyads recruited between 1986 and 2009. The Faroe Islands is a subarctic fishing community, where pilot whale meat and blubber are part of the traditional marine diet. Exposures were measured in maternal hair, serum...... or umbilical cord blood. Confounder adjusted logistic regression models were used to assess the associations between maternal exposures and the secondary sex ratio. A doubling in ΣPCB, p,p'-DDE and mercury concentrations were associated with increased odds by 8% (95% CI = 0-16%), 7% (95% CI = 0-14%) and 9% (95...

  1. Methylmercury cycling, bioaccumulation, and export from agricultural and non-agricultural wetlands in the Yolo Bypass

    Science.gov (United States)

    Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark; Fleck, Jacob; Alpers, Charles N.; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Stricker, Craig; Stephenson, Mark; Feliz, David; Gill, Gary; Bachand, Philip; Brice, Ann; Kulakow, Robin

    2010-01-01

    This 18-month field study addresses the seasonal and spatial patterns and processes controlling methylmercury (MeHg) production, bioaccumulation, and export from natural and agricultural wetlands of the Yolo Bypass Wildlife Area (YBWA). The data were collected in conjuntion with a Proposition 40 grant from the State Water Resources Control Board in support of the development of Best Management Practices (BMP's) for reducing MeHg loading from agricultural lands in the wetland-dominated Yolo Bypass to the Sacramento-San Joaquin River Delta. The four managemenr-based questions addressed in this study were: 1. Is there a different among agricultural and managfed wetland types in terms of Me Hg dynamic (production, degradation, bioaccumulation, or export)?

  2. Comparison of game-farm and wild-strain mallard ducks in accumulation of methylmercury

    Science.gov (United States)

    Heinz, G.H.

    1979-01-01

    The accumulation of mercury was compared in game-farm and wild-strain mallard ducks fed a diet containing 0.5 ppm mercury in the form of methylmercury dicyandiamide. There were no significant differences between the two strains in levels of mercury that accumulated in blood, kidney, liver, breast muscle, brain, eggs, or ducklings. Mercury levels in blood were significantly correlated with levels in other tissues and eggs, as were levels in down feathers of ducklings with levels in carcasses of ducklings. The results indicate that game-farm mallards are probably suitable substitutes for wild mallards in toxicological work, that blood samples can be used to estimate levels of mercury in other tissues of adults, and that down feathers are predictive of mercury levels in duckling carcasses.

  3. Demethylation of methylmercury in growing rice plants: An evidence of self-detoxification

    International Nuclear Information System (INIS)

    Xu, Xiaohan; Zhao, Jiating; Li, Yunyun; Fan, Yuqin; Zhu, Nali; Gao, Yuxi; Li, Bai; Liu, Hanyu; Li, Yu-Feng

    2016-01-01

    Mercury (Hg) is a global pollutant that poses a serious threat to human and the environment. Rice was found as an important source for human exposure to Hg in some areas. In this study, the transportation and transformation of IHg and MeHg in rice plants exposed to IHg or MeHg were investigated. The IHg and MeHg concentrations in rice roots and shoots collected every five days were analyzed by HPLC-ICP-MS and SR-XANES. When exposed to MeHg, the percent of IHg in rice roots and shoots increased while MeHg decreased significantly, suggesting prominent demethylation of MeHg occurred. However no notable MeHg was found in both roots and shoots of rice plant when exposed to IHg. SR-XANES analysis further confirmed the demethylation of MeHg with rice. This study provides a new finding that demethylation of MeHg could occur in growing rice, which may be a self-defense process of rice plant. - Graphical abstract: Inorganic mercury in Rice (Oryza sativa L.) plants exposed to methylmercury was detected: An evidence of rice plant against methylmercury phytotoxicity. Display Omitted - Highlights: • Demethylation of MeHg in rice plant was found in rice root. • Hg in rice roots mainly present as MeHg-SR or RS-Hg-SR form. • MeHg-SR in roots can be gradually transformed to RS-Hg-SR with rice growth. - Demethylation of MeHg in growing rice.

  4. Toxic effects of dietary methylmercury on immune system development in nestling American kestrels (Falco sparverius)

    Science.gov (United States)

    Fallacara, Dawn M.; Halbrook, Richard S.; French, John B.

    2011-01-01

    This study evaluated the effects of dietary methylmercury (MeHg) on immune system development in captive-reared nestling American kestrels (Falco sparverius) to determine whether T cell–mediated and antibody-mediated adaptive immunity are targets for MeHg toxicity at environmentally relevant concentrations. Nestlings received various diets, including 0 (control), 0.6, and 3.9 μg/g (dry wt) MeHg for up to 18 d posthatch. Immunotoxicity endpoints included cell-mediated immunity (CMI) using the phytohemagglutinin (PHA) skin-swelling assay and antibody-mediated immune response via the sheep red blood cell (SRBC) hemagglutination assay. T cell– and B cell–dependent histological parameters in the spleen, thymus, and bursa of Fabricius were correlated with the functional assays. For nestlings in the 0.6 and 3.9 μg/g MeHg groups, CMI was suppressed by 73 and 62%, respectively, at 11 d of age. Results of this functional assay were correlated with T cell–dependent components of the spleen and thymus. Dose-dependent lymphoid depletion in spleen tissue directly affected the proliferation of T-lymphocyte populations, insofar as lower stimulation indexes from the PHA assay occurred in nestlings with lower proportions of splenic white pulp and higher THg concentrations. Nestlings in the 3.9 μg/g group also exhibited lymphoid depletion and a lack of macrophage activity in the thymus. Methylmercury did not have a noticeable effect on antibody-mediated immune function or B cell–dependent histological correlates. We conclude that T cell–mediated immunosuppression is the primary target of MeHg toward adaptive immunity in developing kestrels. This study provides evidence that environmentally relevant concentrations of MeHg may compromise immunocompetence in a developing terrestrial predator and raises concern regarding the long-term health effects of kestrels that were exposed to dietary MeHg during early avian development.

  5. Accumulation, subcellular distribution and toxicity of inorganic mercury and methylmercury in marine phytoplankton

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yun [Division of Life Science, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong); Wang Wenxiong, E-mail: wwang@ust.hk [Division of Life Science, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong)

    2011-10-15

    We examined the accumulation, subcellular distribution, and toxicity of Hg(II) and MeHg in three marine phytoplankton (the diatom Thalassiosira pseudonana, the green alga Chlorella autotrophica, and the flagellate Isochrysis galbana). For MeHg, the inter-species toxic difference could be best interpreted by the total cellular or intracellular accumulation. For Hg(II), both I. galbana and T. pseudonana exhibited similar sensitivity, but they each accumulated a different level of Hg(II). A higher percentage of Hg(II) was bound to the cellular debris fraction in T. pseudonana than in I. galbana, implying that the cellular debris may play an important role in Hg(II) detoxification. Furthermore, heat-stable proteins were a major binding pool for MeHg, while the cellular debris was an important binding pool for Hg(II). Elucidating the different subcellular fates of Hg(II) and MeHg may help us understand their toxicity in marine phytoplankton at the bottom of aquatic food chains. - Highlights: > The inter-species toxic difference of methylmercury in marine phytoplankton can be explained by its total cellular or intracellular accumulation. > The inter-species toxic difference of inorganic mercury in marine phytoplankton can be explained by its subcellular distribution. > Heat-stable protein was a major binding pool for MeHg, while the cellular debris was an important binding pool for Hg(II). - The inter-species difference in methylmercury and inorganic mercury toxicity in phytoplankton can be explained by cellular accumulation and subcellular distribution.

  6. Accumulation, subcellular distribution and toxicity of inorganic mercury and methylmercury in marine phytoplankton

    International Nuclear Information System (INIS)

    Wu Yun; Wang Wenxiong

    2011-01-01

    We examined the accumulation, subcellular distribution, and toxicity of Hg(II) and MeHg in three marine phytoplankton (the diatom Thalassiosira pseudonana, the green alga Chlorella autotrophica, and the flagellate Isochrysis galbana). For MeHg, the inter-species toxic difference could be best interpreted by the total cellular or intracellular accumulation. For Hg(II), both I. galbana and T. pseudonana exhibited similar sensitivity, but they each accumulated a different level of Hg(II). A higher percentage of Hg(II) was bound to the cellular debris fraction in T. pseudonana than in I. galbana, implying that the cellular debris may play an important role in Hg(II) detoxification. Furthermore, heat-stable proteins were a major binding pool for MeHg, while the cellular debris was an important binding pool for Hg(II). Elucidating the different subcellular fates of Hg(II) and MeHg may help us understand their toxicity in marine phytoplankton at the bottom of aquatic food chains. - Highlights: → The inter-species toxic difference of methylmercury in marine phytoplankton can be explained by its total cellular or intracellular accumulation. → The inter-species toxic difference of inorganic mercury in marine phytoplankton can be explained by its subcellular distribution. → Heat-stable protein was a major binding pool for MeHg, while the cellular debris was an important binding pool for Hg(II). - The inter-species difference in methylmercury and inorganic mercury toxicity in phytoplankton can be explained by cellular accumulation and subcellular distribution.

  7. Impact of macrozoobenthic bioturbation and wind fluctuation interactions on net methylmercury in freshwater lakes.

    Science.gov (United States)

    Wang, Peifang; Yao, Yu; Wang, Chao; Hou, Jun; Qian, Jin; Miao, Lingzhan

    2017-11-01

    The methylmercury (MeHg) as the toxic fractions has presented significant threats to biota in freshwater ecosystems. Hg methylation process is demonstrated to be manipulated by biota process (benthic disturbance and algae bloom existence) as well as the abiotic influence (wind fluctuation and illumination intensity) in freshwater ecosystems. However, the mechanisms influencing Hg methylation are still unclear, and the coupled influences of the biotic and abiotic process with the shifts in variation on methylmercury remain unexplored. Accordingly, an annular flume experiment which simulated the freshwater ecosystem, was conducted for 108 days to examine the influences of typical disturbance by chironomid larvae and wind fluctuations on MeHg variation in sediment profiles. The in-situ, passive sampler technique of revealing diffusive gradients in thin films (DGT) encompassed the special resin, based on referenced extraction and coloration-computer imaging densitometry, were employed to obtain labile MeHg, Fe, and S concentrations at high resolution. The results indicate that larval bioturbation during the initial period of the experiment could diminish bioavailable MeHg concentrations and change the diffusion direction of MeHg fluxes. However, this inhibitive effect on MeHg concentrations ceased with larvae eclosion. Compared to bioturbation, wind fluctuation exerted slow but sustained inhibition on MeHg release. Furthermore, the eight parameters (dissolved organic carbon (DOC), DO, labile Fe and S concentrations, pH, sulfate-reducing bacteria (SRB) abundance in sediment, oxidation-reduction potential (ORP) and EC) could explain more of variation in MeHg concentrations which indicated by the canonical correspondence analysis. And these eight parameters manifest higher explanatory power for MeHg distributed in newly formed sediment. More notably, the comparison results of the multiple and simple regression directly demonstrated the DOC was the fundamental and robust

  8. Effects of methylmercury exposure on the immune function of juvenile common loons (Gavia immer)

    Science.gov (United States)

    Kenow, K.P.; Grasman, K.A.; Hines, R.K.; Meyer, M.W.; Gendron-Fitzpatrick, A.; Spalding, M.G.; Gray, B.R.

    2007-01-01

    We conducted a dose-response laboratory study to quantify the level of exposure to dietary Hg, delivered as methylmercury chloride (CH3HgCl), that is associated with suppressed immune function in captive-reared common loon (Gavia immer) chicks. We used the phytohemagglutinin (PHA) skin test to assess T-lymphocyte function and the sheep red blood cell (SRBC) hemagglutination test to measure antibody-mediated immunity. The PHA stimulation index among chicks receiving dietary Hg treatment did not differ significantly from those of chicks on the control diet (p = 0.15). Total antibody (immunoglobulin [Ig] M [primary antibody] + IgG [secondary response]) production to the SRBC antigen in chicks treated with dietary methylmercury (MeHg), however, was suppressed (p = 0.04) relative to chicks on control diets. Analysis indicated suppression of total Ig production (p = 0.025 with comparisonwise ?? level = 0.017) between control and 0.4 ??g Hg/g wet food intake treatment groups. Furthermore, the control group exhibited a higher degree of variability in antibody response compared to the Hg groups, suggesting that in addition to reducing the mean response, Hg treatment reduced the normal variation attributable to other biological factors. We observed bursal lymphoid depletion in chicks receiving the 1.2 ??g Hg/g treatment (p = 0.017) and a marginally significant effect (p = 0.025) in chicks receiving the 0.4 ??g Hg/g diet. These findings suggest that common loon chick immune systems may be compromised at an ecologically relevant dietary exposure concentration (0.4 ??g Hg/g wet wt food intake). We also found that chicks hatched from eggs collected from low-pH lakes exhibited higher levels of lymphoid depletion in bursa tissue relative to chicks hatched from eggs collected from neutral-pH lakes. ?? 2007 SETAC.

  9. Extreme environment electronics

    CERN Document Server

    Cressler, John D

    2012-01-01

    Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

  10. Distribution of polycyclic aromatic hydrocarbons (PAHs) and tributyltin (TBT) in Barcelona harbour sediments and their impact on benthic communities

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Llado, Xavier [Environmental Technology Area, CTM-UPC, Avda. Bases de Manresa 1, 08240 Manresa (Spain); Gibert, Oriol [Environmental Technology Area, CTM-UPC, Avda. Bases de Manresa 1, 08240 Manresa (Spain); Marti, Vicens [Environmental Technology Area, CTM-UPC, Avda. Bases de Manresa 1, 08240 Manresa (Spain)]. E-mail: vicens.marti@upc.edu; Diez, Sergi [Environmental Chemistry Department, IIQAB-CSIC, c/Jordi Girona 18-26, 08034 Barcelona (Spain); Environmental Geology Department, ICTJA-CSIC, Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain); Romo, Javier [Environmental Service of Barcelona Harbour Authority, Carretera de la Circumval.lacio, s/n, Tram VI, Sector 6, Barcelona (Spain); Bayona, Josep Maria [Environmental Chemistry Department, IIQAB-CSIC, c/Jordi Girona 18-26, 08034 Barcelona (Spain); Pablo, Joan de [Environmental Technology Area, CTM-UPC, Avda. Bases de Manresa 1, 08240 Manresa (Spain)

    2007-09-15

    Sediments have long been recognised as a sink for many contaminants like polycyclic aromatic hydrocarbons (PAHs) and tributyltin (TBT), which by virtue of their nature can strongly adsorb onto sediments affecting the benthic community inhabiting them. Using geographical information systems, this study reports and combines the results of several already existing studies along Barcelona harbour in order to assess the potential ecological impacts of these contaminants on the benthos of the harbour ecosystem. Chemical analysis indicated low to moderate contents of PAHs and high contents of TBT in sediments in Barcelona harbour. Comparison against existing sediment quality guidelines (SQGs) indicated that acutely toxic effects would not be expected for PAHs but for TBT, which represents a serious environmental threat for the benthic community. Benthos surveys revealed a deterioration of the benthic community throughout the harbour, especially in the inner port. - A possible correlation exists between TBT concentration in sediments and ecological effects on benthos in Barcelona harbour.

  11. Interdisciplinary study for the evaluation of biochemical alterations on mussel Mytilus galloprovincialis exposed to a tributyltin-polluted area

    Energy Technology Data Exchange (ETDEWEB)

    Magi, Emanuele [University of Genoa, Department of Chemistry and Industrial Chemistry, Genoa (Italy); Department of Chemistry and Industrial Chemistry, Genoa (Italy); Liscio, Camilla; Pistarino, Erika; Santamaria, Barbara; Di Carro, Marina; Tiso, Micaela; Cosulich, M.E. [University of Genoa, Department of Chemistry and Industrial Chemistry, Genoa (Italy); Scaloni, Andrea; Renzone, Giovanni [National Research Council, Proteomic and Mass Spectrometry Laboratory, ISPAAM, Naples (Italy)

    2008-05-15

    An interdisciplinary approach was employed to monitor the concentration and the effects of butyltin compounds in mussels (Mytilus galloprovincialis). Tissues from animals exposed to a marine area (Vado Ligure harbour) with a high concentration of tributyltin (TBT) were analysed and compared with control samples. TBT concentrations were measured by gas chromatography-mass spectrometry and the protein pattern in gill tissues was studied by proteomic analysis. Several proteomic signatures associated with contaminant exposure were observed; spots that were significantly increased in all contaminated samples were identified by mass spectrometry as fragments of {beta}-tubulin. The degradation of {beta}-tubulin was then confirmed by western blot analysis with specific anti-{beta}-tubulin antibody. The effects observed on mussel gills after exposure in the TBT-polluted area are discussed. (orig.)

  12. Distribution of polycyclic aromatic hydrocarbons (PAHs) and tributyltin (TBT) in Barcelona harbour sediments and their impact on benthic communities

    International Nuclear Information System (INIS)

    Martinez-Llado, Xavier; Gibert, Oriol; Marti, Vicens; Diez, Sergi; Romo, Javier; Bayona, Josep Maria; Pablo, Joan de

    2007-01-01

    Sediments have long been recognised as a sink for many contaminants like polycyclic aromatic hydrocarbons (PAHs) and tributyltin (TBT), which by virtue of their nature can strongly adsorb onto sediments affecting the benthic community inhabiting them. Using geographical information systems, this study reports and combines the results of several already existing studies along Barcelona harbour in order to assess the potential ecological impacts of these contaminants on the benthos of the harbour ecosystem. Chemical analysis indicated low to moderate contents of PAHs and high contents of TBT in sediments in Barcelona harbour. Comparison against existing sediment quality guidelines (SQGs) indicated that acutely toxic effects would not be expected for PAHs but for TBT, which represents a serious environmental threat for the benthic community. Benthos surveys revealed a deterioration of the benthic community throughout the harbour, especially in the inner port. - A possible correlation exists between TBT concentration in sediments and ecological effects on benthos in Barcelona harbour

  13. Assessment of tributyltin contamination based on imposex in Stramonita rustica (Mollusca: Gastropoda along southern Bahia coast, northeastern Brazil

    Directory of Open Access Journals (Sweden)

    G. C. Zeidan

    Full Text Available Abstract This study investigated the effects of tributyltin (TBT on the morphology of the genital system of the gastropod Stramonita rustica in southern Bahia, Brazil. For this, 330 specimens were collected during the summer of 2014 at eight sampling points to ascertain whether male sex organs had developed in addition to the complete female genital tract in females (= imposex. The analyses were made under a stereoscopic microscope. Imposex and their associated indexes, and the sterile females, exhibited the highest rates in harbors and shipyards areas. Despite the total ban of TBT in anti-fouling paints on a global scale since 2003, the results of this and other studies indicate the continued use of those paints on the Brazilian coast. This shows the inefficiency of existing legislation and the need to strengthen enforcement of the ban.

  14. Assessment of tributyltin contamination based on imposex in Stramonita rustica (Mollusca: Gastropoda) along southern Bahia coast, northeastern Brazil.

    Science.gov (United States)

    Zeidan, G C; Boehs, G

    2017-03-01

    This study investigated the effects of tributyltin (TBT) on the morphology of the genital system of the gastropod Stramonita rustica in southern Bahia, Brazil. For this, 330 specimens were collected during the summer of 2014 at eight sampling points to ascertain whether male sex organs had developed in addition to the complete female genital tract in females (= imposex). The analyses were made under a stereoscopic microscope. Imposex and their associated indexes, and the sterile females, exhibited the highest rates in harbors and shipyards areas. Despite the total ban of TBT in anti-fouling paints on a global scale since 2003, the results of this and other studies indicate the continued use of those paints on the Brazilian coast. This shows the inefficiency of existing legislation and the need to strengthen enforcement of the ban.

  15. Aeromonas veronii, a tributyltin (TBT)-degrading bacterium isolated from an estuarine environment, Ria de Aveiro in Portugal.

    Science.gov (United States)

    Cruz, Andreia; Caetano, Tânia; Suzuki, Satoru; Mendo, Sónia

    2007-12-01

    Organotin compounds are used in a variety of industrial processes therefore their subsequent discharge into the environment is widespread. Bacteria play an important role in biogeochemical transformations acting as natural decontamination agents. Therefore, screening for tributyltin (TBT)-resistant and -degrading bacteria is relevant for the selection of isolates with decontamination ability of these polluted areas. With this purpose, 50 strains were isolated from sediment and water from Ria de Aveiro and their tolerance to TBT, up to 3mM, was evaluated. Generally, occurrence of highly TBT-resistant bacteria was observed, and Gram negative bacteria exhibited more tolerance to TBT than Gram positive bacteria. A memory response was observed when bacteria were progressively exposed to increasingly higher TBT concentrations. One isolate, Aeromonas veronii Av27, highly resistant to TBT (3mM) uses this compound as carbon source and degrades it to less toxic compounds.

  16. The effects of bis(tributyltin) oxide on the development, reproduction and sex ratio of calanoid copepod Pseudodiaptomus marinus

    Science.gov (United States)

    Huang, Ying; Zhu, Liyan; Liu, Guangxing

    2006-08-01

    In order to study the biological effects by bis(tributyltin) oxide (TBTO) exposure, chronic toxicity tests were conducted on the calanoid copepod Pseudodiaptomus marinus over two generations. The results indicated that nauplii were more sensitive than copepodites. F1 copepods were more vulnerable than F0 copepods and a drastic increase in mortality was observed as the TBTO concentration became higher. Exposure of copepods to 60 ng l -1 TBTO concentration reduced the fecundity and resulted in some females being infecund (in the F0 generation). The time to the first egg sac for females in the F1 generation exposed to 6 ng l -1 TBTO concentration was significantly reduced, and the fecundity of this generation was increased. The female-to-male ratio in the F1 generation exposed to 20 ng l -1 TBTO concentration was significantly reduced. These results show that the current ambient TBT concentration may influence populations of copepods in the coastal environment.

  17. Pharmacological evaluation of the mechanisms involved in increased adiposity in zebrafish triggered by the environmental contaminant tributyltin

    Energy Technology Data Exchange (ETDEWEB)

    Ouadah-Boussouf, Nafia; Babin, Patrick J., E-mail: p.babin@gpp.u-bordeaux1.fr

    2016-03-01

    One proposed contributing factor to the rise in overweight and obesity is exposure to endocrine disrupting chemicals. Tributyltin chloride (TBT), an organotin, induces adipogenesis in cell culture models and may increases adipose mass in vivo in vertebrate model organisms. It has been hypothesized that TBT acts via the peroxisome proliferator activated receptor (PPAR)γ-dependent pathway. However, the mechanisms involved in the effects of TBT exposure on in vivo adipose tissue metabolism remain unexplored. Semitransparent zebrafish larvae, with their well-developed white adipose tissue, offer a unique opportunity for studying the effects of toxicant chemicals and pharmaceuticals on adipocyte biology and whole-organism adiposity in a vertebrate model. Within hours, zebrafish larvae, treated at environmentally-relevant nanomolar concentrations of TBT, exhibited a remarkable increase in adiposity linked to adipocyte hypertrophy. Under the experimental conditions used, we also demonstrated that zebrafish larvae adipose tissue proved to be highly responsive to selected human nuclear receptor agonists and antagonists. Retinoid X receptor (RXR) homodimers and RXR/liver X receptor heterodimers were suggested to be in vivo effectors of the obesogenic effect of TBT on zebrafish white adipose tissue. RXR/PPARγ heterodimers may be recruited to modulate adiposity in zebrafish but were not a necessary requirement for the short term in vivo TBT obesogenic effect. Together, the present results suggest that TBT may induce the promotion of triacylglycerol storage in adipocytes via RXR-dependent pathways without necessary using PPAR isoforms. - Highlights: • The environmental contaminant tributyltin (TBT) may promote obesity development. • TBT may induce adipocyte hypertrophy through a PPARγ independent mechanism. • RXR/RXR and RXR/LXR dimers are potential in vivo effectors of TBT in zebrafish.

  18. Tributyltin chloride increases phenylephrine-induced contraction and vascular stiffness in mesenteric resistance arteries from female rats

    International Nuclear Information System (INIS)

    Ribeiro Júnior, Rogério Faustino; Marques, Vinicius Bermond; Nunes, Dieli Oliveira; Ronconi, Karoline de Sousa; Araújo, Julia F.P. de; Rodrigues, Paula Lopes; Padilha, Alessandra Simão; Vassallo, Dalton Valentim; Graceli, Jones B.; Stefanon, Ivanita

    2016-01-01

    Tributyltin chloride (TBT) is an organotin compound that reduces estrogen levels in female rats. We aimed to investigate the effects of TBT exposure on vascular tonus and vascular remodelling in the resistance arteries of female rats. Rats were treated daily with TBT (500 ng/kg) for 15 days. TBT did not change arterial blood pressure but did modify some morpho-physiological parameters of third-order mesenteric resistance arteries in the following ways: (1) decreased lumen and external diameters; (2) increased wall/lm ratio and wall thickness; (3) decreased distensibility and increased stiffness; (4) increased collagen deposition; and (5) increased pulse wave velocity. TBT exposure increased the phenylephrine-induced contractile response in mesenteric resistance arteries. However, vasodilatation responses induced by acetylcholine and sodium nitroprusside were not modified by TBT. It is suggested that TBT exposure reduces vascular nitric oxide (NO) production, because:(1) L-NAME incubation did not cause a leftward shift in the concentration–response curve for phenylephrine; (2) both eNOS protein expression; (3) in situ NO production were reduced. Incubation with L-NAME; and (4) SOD shifted the phenylephrine response curve to the left in TBT rats. Tiron, catalase, ML-171 and VAS2870 decreased vascular reactivity to phenylephrine only in TBT rats. Moreover, increased superoxide anion production was observed in the mesenteric resistance arteries of TBT rats accompanied by an increase in gp91phox, catalase, AT 1 receptor and total ERK1/2 protein expression. In conclusion, these findings show that TBT induced alterations are most likely due to a reduction of NO production combined with increased O 2 − production derived from NADPH oxidase and ERK1/2 activation. These findings offer further evidence that TBT is an environmental risk factor for cardiovascular disease. - Highlights: • Tributyltin chloride reduces estrogen levels in female rats. • Treatment with TBT

  19. Pharmacological evaluation of the mechanisms involved in increased adiposity in zebrafish triggered by the environmental contaminant tributyltin

    International Nuclear Information System (INIS)

    Ouadah-Boussouf, Nafia; Babin, Patrick J.

    2016-01-01

    One proposed contributing factor to the rise in overweight and obesity is exposure to endocrine disrupting chemicals. Tributyltin chloride (TBT), an organotin, induces adipogenesis in cell culture models and may increases adipose mass in vivo in vertebrate model organisms. It has been hypothesized that TBT acts via the peroxisome proliferator activated receptor (PPAR)γ-dependent pathway. However, the mechanisms involved in the effects of TBT exposure on in vivo adipose tissue metabolism remain unexplored. Semitransparent zebrafish larvae, with their well-developed white adipose tissue, offer a unique opportunity for studying the effects of toxicant chemicals and pharmaceuticals on adipocyte biology and whole-organism adiposity in a vertebrate model. Within hours, zebrafish larvae, treated at environmentally-relevant nanomolar concentrations of TBT, exhibited a remarkable increase in adiposity linked to adipocyte hypertrophy. Under the experimental conditions used, we also demonstrated that zebrafish larvae adipose tissue proved to be highly responsive to selected human nuclear receptor agonists and antagonists. Retinoid X receptor (RXR) homodimers and RXR/liver X receptor heterodimers were suggested to be in vivo effectors of the obesogenic effect of TBT on zebrafish white adipose tissue. RXR/PPARγ heterodimers may be recruited to modulate adiposity in zebrafish but were not a necessary requirement for the short term in vivo TBT obesogenic effect. Together, the present results suggest that TBT may induce the promotion of triacylglycerol storage in adipocytes via RXR-dependent pathways without necessary using PPAR isoforms. - Highlights: • The environmental contaminant tributyltin (TBT) may promote obesity development. • TBT may induce adipocyte hypertrophy through a PPARγ independent mechanism. • RXR/RXR and RXR/LXR dimers are potential in vivo effectors of TBT in zebrafish.

  20. Methylmercury poisoning

    Science.gov (United States)

    ... Goldfrank's Toxicologic Emergencies . 10th ed. New York, NY: McGraw Hill-Medical; 2015:chap 98. Theobald JL, Mycyk ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  1. Extreme value distributions

    CERN Document Server

    Ahsanullah, Mohammad

    2016-01-01

    The aim of the book is to give a through account of the basic theory of extreme value distributions. The book cover a wide range of materials available to date. The central ideas and results of extreme value distributions are presented. The book rwill be useful o applied statisticians as well statisticians interrested to work in the area of extreme value distributions.vmonograph presents the central ideas and results of extreme value distributions.The monograph gives self-contained of theory and applications of extreme value distributions.

  2. Intra- and inter-basin mercury comparisons: Importance of basin scale and time-weighted methylmercury estimates

    International Nuclear Information System (INIS)

    Bradley, Paul M.; Journey, Celeste A.; Brigham, Mark E.; Burns, Douglas A.; Button, Daniel T.; Riva-Murray, Karen

    2013-01-01

    To assess inter-comparability of fluvial mercury (Hg) observations at substantially different scales, Hg concentrations, yields, and bivariate-relations were evaluated at nested-basin locations in the Edisto River, South Carolina and Hudson River, New York. Differences between scales were observed for filtered methylmercury (FMeHg) in the Edisto (attributed to wetland coverage differences) but not in the Hudson. Total mercury (THg) concentrations and bivariate-relationships did not vary substantially with scale in either basin. Combining results of this and a previously published multi-basin study, fish Hg correlated strongly with sampled water FMeHg concentration (ρ = 0.78; p = 0.003) and annual FMeHg basin yield (ρ = 0.66; p = 0.026). Improved correlation (ρ = 0.88; p < 0.0001) was achieved with time-weighted mean annual FMeHg concentrations estimated from basin-specific LOADEST models and daily streamflow. Results suggest reasonable scalability and inter-comparability for different basin sizes if wetland area or related MeHg-source-area metrics are considered. - Highlights: ► National scale mercury assessments integrate small scale study results. ► Basin scale differences and representativeness of fluvial mercury samples are concerns. ► Wetland area, not basin size, predicts inter-basin methylmercury variability. ► Time-weighted methylmercury estimates improve the prediction of mercury in basin fish. - Fluvial methylmercury concentration correlates with wetland area not basin scale and time-weighted estimates better predict basin top predator mercury than discrete sample estimates.

  3. Ecologically-relevant exposure to methylmercury during early development does not affect adult phenotype in zebra finches (Taeniopygia guttata).

    Science.gov (United States)

    Morran, Spencer A M; Elliott, John E; Young, Jessica M L; Eng, Margaret L; Basu, Niladri; Williams, Tony D

    2018-04-01

    Methylmercury causes behavioural and reproductive effects in adult mammals via early developmental exposure. Similar studies in birds are limited and mostly focussed on aquatic systems, but recent work has reported high blood mercury concentrations in terrestrial, passerine songbirds. We used the zebra finch (Taeniopygia guttata) as a model to explore the long-term effects of early developmental exposure to methylmercury exposure. Chicks were dosed orally with either the vehicle control, 0.0315 µg Hg/g bw/day, or 0.075 µg Hg/g bw/day throughout the nestling period (days 1-21 post-hatching). We then measured (a) short-term effects on growth, development, and behaviour (time to self-feeding, neophobia) until 30 days of age (independence), and (b) long-term effects on courtship behaviour and song (males) and reproduction (females) once methylmercury-exposed birds reached sexual maturity (90 days post-hatching). High methylmercury treated birds had mean blood mercury of 0.734 ± 0.163 µg/g at 30 days post-hatching, within the range of values reported for field-sampled songbirds at mercury contaminated sites. However, there were no short-term effects of treatment on growth, development, and behaviour of chicks, and no long-term effects on courtship behaviour and song in males or reproductive performance in females. These results suggest that the nestling period is not a critical window for sensitivity to mercury exposure in zebra finches. Growing nestlings can reduce blood mercury levels through somatic growth and depuration into newly growing feathers, and as a result they might actually be less susceptible compared to adult birds receiving the same level of exposure.

  4. Short-term effect of severe exposure to methylmercury on atherosclerotic heart disease and hypertension mortality in Minamata.

    Science.gov (United States)

    Inoue, Sachiko; Yorifuji, Takashi; Tsuda, Toshihide; Doi, Hiroyuki

    2012-02-15

    Recent studies suggest potential adverse effects of methylmercury exposure on myocardial infarction and hypertension, although the evidence is still limited. We thus evaluated this association using age-standardized mortality ratios (ASMRs) in Minamata, where severe methylmercury poisoning had occurred. We obtained mortality data from annual vital statistics and demographic statistics from census. We then compared mortality of atherosclerotic heart disease including degenerative heart disease and hypertension in Minamata-city with those in Kumamoto Prefecture, which includes Minamata city, as a control. We estimated ASMRs and 95% confidence intervals (CIs) during the period from 1953 to 1970. ASMRs of atherosclerotic heart disease were continuously decreased during the period from 1953 to 1967. In contrast, the ASMR of hypertension was significantly elevated during the period from 1963 to 1967 (SMR=1.38, CI; 1.06-1.80); but they decreased later. Although dilution is present in this ecological study, our study supports the notion that methylmercury exposure induces hypertension. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Increase in Nutrients, Mercury, and Methylmercury as a Consequence of Elevated Sulfate Reduction to Sulfide in Experimental Wetland Mesocosms

    Science.gov (United States)

    Myrbo, A.; Swain, E. B.; Johnson, N. W.; Engstrom, D. R.; Pastor, J.; Dewey, B.; Monson, P.; Brenner, J.; Dykhuizen Shore, M.; Peters, E. B.

    2017-11-01

    Microbial sulfate reduction (MSR) in both freshwater and marine ecosystems is a pathway for the decomposition of sedimentary organic matter (OM) after oxygen has been consumed. In experimental freshwater wetland mesocosms, sulfate additions allowed MSR to mineralize OM that would not otherwise have been decomposed. The mineralization of OM by MSR increased surface water concentrations of ecologically important constituents of OM: dissolved inorganic carbon, dissolved organic carbon, phosphorus, nitrogen, total mercury, and methylmercury. Increases in surface water concentrations, except for methylmercury, were in proportion to cumulative sulfate reduction, which was estimated by sulfate loss from the surface water into the sediments. Stoichiometric analysis shows that the increases were less than would be predicted from ratios with carbon in sediment, indicating that there are processes that limit P, N, and Hg mobilization to, or retention in, surface water. The highest sulfate treatment produced high levels of sulfide that retarded the methylation of mercury but simultaneously mobilized sedimentary inorganic mercury into surface water. As a result, the proportion of mercury in the surface water as methylmercury peaked at intermediate pore water sulfide concentrations. The mesocosms have a relatively high ratio of wall and sediment surfaces to the volume of overlying water, perhaps enhancing the removal of nutrients and mercury to periphyton. The presence of wild rice decreased sediment sulfide concentrations by 30%, which was most likely a result of oxygen release from the wild rice roots. An additional consequence of the enhanced MSR was that sulfate additions produced phytotoxic levels of sulfide in sediment pore water.

  6. Green synthesis of low-toxicity graphene-fulvic acid with an open band gap enhances demethylation of methylmercury.

    Science.gov (United States)

    Hu, Xiangang; Mu, Li; Lu, Kaicheng; Kang, Jia; Zhou, Qixing

    2014-06-25

    The demethylation of methylmercury has received substantial attention. Here, a novel chemical method for the demethylation of methylmercury is proposed. The low-toxicity graphene-fulvic acid (FA, a ubiquitous material in the environment) was synthesized without the use of a chemical reagent. The hybridized graphene-FA presented an indirect open band gap of 2.25-2.87 eV as well as adequate aqueous dispersion. More importantly, the hybridized graphene-FA exhibited 6- and 10-fold higher photocatalytic efficiencies for the demethylation of methylmercury than FA and free FA with graphene, respectively. This result implies that immobilized, rather than free, FA accelerated the catalysis. Furthermore, inorganic mercuric ion, elemental mercury, and mercuric oxide were identified as the primary demethylation products. For free FA with graphene, graphene quenches the excited-state FA, inhibiting the demethylation by electron transfer. In contrast, the graphene of the self-assembled graphene-FA serves as an electron reservoir, causing electron-hole pair separation. Graphene-FA showed a negligible toxicity toward microalgae compared to graphene. The above results reveal that the green synthesis of graphene and organic molecules is a convenient strategy for obtaining effective cocatalysts.

  7. 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.

  8. Bringing home methylmercury: The construction of an authoritative object of knowledge for a Cree community in northern Quebec

    International Nuclear Information System (INIS)

    Scott, R.T.

    1993-01-01

    Aspects of the construction of methylmercury as an authoritative object of knowledge is examined for the case of Chisasibi, a Cree community on the James Bay coast in northern Quebec. The community is located near large hydroelectric projects, and an extensive institutional apparatus has been established in the Chisasibi area to provide research and education about the resulting contamination of water and fish by methylmercury released by flooding of lands by hydro reservoirs. The historical development of the Cree community is reviewed and the evolution of a particular set of spheres of exchange which mediate economic relations in the region is described. Such relations occur between the Cree communities, the federal and provincial governments, and state and corporate structures tied to the state. Knowledge claims about mercury can be seen as situated among claims of injury in a moral economy which is based on conflict over the James Bay hydroelectric project. The politicization and subsequent medicalization of these knowledge claims are described. Finally, the emergence of particular concepts of normality, risk, and risk group are traced in medical and technocratic discourses about the effects of methylmercury on Canadian aboriginal populations. 122 refs., 2 figs., 3 tabs

  9. Radiogaschromatographic analysis of volatile products of the photolysis of the system bis-(tributyltin)-oxide-(butyl-l-14C)/cellulose

    International Nuclear Information System (INIS)

    Kloetzer, D.; Goerner, H.; Heise, K.H.

    1979-01-01

    Apparatus and method for separation and identification of the products of photochemical decomposition in the system bis(tributyltin)-oxide-(butyl-1- 14 C)/cellulose are described. Ultraviolet radiation causes the formation of n-butane- 14 C and n-octane- 14 C, i.e. 14 C-labelled butyl radicals splitting off from the tin organic compound are stabilized by reactions with H atoms from the photodecomposition of cellulose or by dimerization. (author)

  10. Biological effects of tributyltin chloride (TBTC) in carp (Cyprinus carpio L.); Effetti biologici del tributilstagno cloruro (TBTC) in carpa (Cyprinus carpio L.)

    Energy Technology Data Exchange (ETDEWEB)

    Bressa, Giuliano [ENEL-CRAM Spa, Milan (Italy); Giombelli, Rossana [Milan, Univ. (Italy). Dipt. di Biologia; Prearo, Marino; Bozzetta, Elena [Istituto Zooprofilattico del Piemonte, Liguria e Valle D`Aosta, Turin (Italy); Sisti, Elivio [Centro Studi Ambientali, Rimini (Italy); Cima, Francesca [Padua, Univ. (Italy). Dipt. di Biologia

    1997-01-01

    Organotin compounds are widely used as biocides. In particular, tributyltin chloride (TBTC) is used for the preservation of wood and as antifouling agent in marine paints. The aim of the present investigation was to evaluate the uptake of the TBTC by fish (Cyprinus carpio) fed with contaminated pellets. Histological examination of the thymus of fish treated for 7 days with TBTC showed atrophy with severe lymphocytic depletion. TBTC and its metabolite DBTC were detected in the kidney, liver, spleen, thymus and muscle tissue.

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

    Science.gov (United States)

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

    2014-06-01

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

  12. Prediction of methylmercury accumulation in rice grains by chemical extraction methods

    International Nuclear Information System (INIS)

    Zhu, Dai-Wen; Zhong, Huan; Zeng, Qi-Long; Yin, Ying

    2015-01-01

    To explore the possibility of using chemical extraction methods to predict phytoavailability/bioaccumulation of soil-bound MeHg, MeHg extractions by three widely-used extractants (CaCl 2 , DTPA, and (NH 4 ) 2 S 2 O 3 ) were compared with MeHg accumulation in rice grains. Despite of variations in characteristics of different soils, MeHg extracted by (NH 4 ) 2 S 2 O 3 (highly affinitive to MeHg) correlated well with grain MeHg levels. Thus (NH 4 ) 2 S 2 O 3 extraction, solubilizing not only weakly-bound and but also strongly-bound MeHg, may provide a measure of ‘phytoavailable MeHg pool’ for rice plants. Besides, a better prediction of grain MeHg levels was obtained when growing condition of rice plants was also considered. However, MeHg extracted by CaCl 2 or DTPA, possibly quantifying ‘exchangeable MeHg pool’ or ‘weakly-complexed MeHg pool’ in soils, may not indicate phytoavailable MeHg or predict grain MeHg levels. Our results provided the possibility of predicting MeHg phytoavailability/bioaccumulation by (NH 4 ) 2 S 2 O 3 extraction, which could be useful in screening soils for rice cultivation in contaminated areas. - Highlights: • MeHg extraction by (NH 4 ) 2 S 2 O 3 correlates well with its accumulation in rice grains. • MeHg extraction by (NH 4 ) 2 S 2 O 3 provides a measure of phytoavailable MeHg in soils. • Some strongly-bound MeHg could be desorbed from soils and available to rice plants. • MeHg extraction by CaCl 2 or DTPA could not predict grain MeHg levels. - Methylmercury extraction from soils by (NH 4 ) 2 S 2 O 3 could possibly be used for predicting methylmercury phytoavailability and its bioaccumulation in rice grains

  13. Comparison of total mercury and methylmercury cycling at five sites using the small watershed approach

    Energy Technology Data Exchange (ETDEWEB)

    Shanley, James B. [US Geological Survey, PO Box 628, Montpelier, VT 05601 (United States)], E-mail: jshanley@usgs.gov; Alisa Mast, M. [US Geological Survey, MS 415 Denver Federal Center, Denver, CO 80225 (United States)], E-mail: mamast@usgs.gov; Campbell, Donald H. [US Geological Survey, MS 415 Denver Federal Center, Denver, CO 80225 (United States)], E-mail: dhcampbe@usgs.gov; Aiken, George R. [US Geological Survey, 3215 Marine Street, Suite E-127, Boulder, CO 80303 (United States)], E-mail: graiken@usgs.gov; Krabbenhoft, David P. [US Geological Survey, 8505 Research Way, Middleton, WI 53562 (United States)], E-mail: dpkrabbe@usgs.gov; Hunt, Randall J. [US Geological Survey, 8505 Research Way, Middleton, WI 53562 (United States)], E-mail: rjhunt@usgs.gov; Walker, John F. [US Geological Survey, 8505 Research Way, Middleton, WI 53562 (United States)], E-mail: jfwalker@usgs.gov; Schuster, Paul F. [US Geological Survey, 3215 Marine Street, Suite E-127, Boulder, CO 80303 (United States)], E-mail: pschuste@usgs.gov; Chalmers, Ann [US Geological Survey, PO Box 628, Montpelier, VT 05601 (United States)], E-mail: chalmers@usgs.gov; Aulenbach, Brent T. [US Geological Survey, 3039 Amwiler Road, Suite 130, Atlanta, GA 30360 (United States)], E-mail: btaulenb@usgs.gov; Peters, Norman E. [US Geological Survey, 3039 Amwiler Road, Suite 130, Atlanta, GA 30360 (United States)], E-mail: nepeters@usgs.gov; Marvin-DiPasquale, Mark [US Geological Survey, 345 Middlefield Rd., MS 480, Menlo Park, CA 94025 (United States)], E-mail: mmarvin@usgs.gov; Clow, David W. [US Geological Survey, MS 415 Denver Federal Center, Denver, CO 80225 (United States)], E-mail: dwclow@usgs.gov; Shafer, Martin M. [Environmental Chemistry and Technology and Wisconsin State Laboratory of Hygiene, University of Wisconsin, Madison, WI 53706 (United States)], E-mail: mmshafer@wisc.edu

    2008-07-15

    The small watershed approach is well-suited but underutilized in mercury research. We applied the small watershed approach to investigate total mercury (THg) and methylmercury (MeHg) dynamics in streamwater at the five diverse forested headwater catchments of the US Geological Survey Water, Energy, and Biogeochemical Budgets (WEBB) program. At all sites, baseflow THg was generally less than 1 ng L{sup -1} and MeHg was less than 0.2 ng L{sup -1}. THg and MeHg concentrations increased with streamflow, so export was primarily episodic. At three sites, THg and MeHg concentration and export were dominated by the particulate fraction in association with POC at high flows, with maximum THg (MeHg) concentrations of 94 (2.56) ng L{sup -1} at Sleepers River, Vermont; 112 (0.75) ng L{sup -1} at Rio Icacos, Puerto Rico; and 55 (0.80) ng L{sup -1} at Panola Mt., Georgia. Filtered (<0.7 {mu}m) THg increased more modestly with flow in association with the hydrophobic acid fraction (HPOA) of DOC, with maximum filtered THg concentrations near 5 ng L{sup -1} at both Sleepers and Icacos. At Andrews Creek, Colorado, THg export was also episodic but was dominated by filtered THg, as POC concentrations were low. MeHg typically tracked THg so that each site had a fairly constant MeHg/THg ratio, which ranged from near zero at Andrews to 15% at the low-relief, groundwater-dominated Allequash Creek, Wisconsin. Allequash was the only site with filtered MeHg consistently above detection, and the filtered fraction dominated both THg and MeHg. Relative to inputs in wet deposition, watershed retention of THg (minus any subsequent volatilization) was 96.6% at Allequash, 60% at Sleepers, and 83% at Andrews. Icacos had a net export of THg, possibly due to historic gold mining or frequent disturbance from landslides. Quantification and interpretation of Hg dynamics was facilitated by the small watershed approach with emphasis on event sampling. - High-flow sampling reveals strong contrasts in total

  14. A Unified Model for Methylmercury Formation and Bioaccumulation in the Global Ocean

    Science.gov (United States)

    Zhang, Y.; Schartup, A. T.; Soerensen, A.; Dutkiewicz, S.; Sunderland, E. M.

    2017-12-01

    Marine fish consumption is the main exposure pathway for methylmercury (MeHg), a neurotoxin, in many countries. The Hg in the ocean is mainly from atmospheric deposition in inorganic forms. How the deposited Hg is methylated and accumulated in biota remain an open question. We develop a 3D model (MITgcm) for MeHg formation and bioaccumulation in the global ocean and evaluate the driving factors. The model is based on a previous published inorganic Hg model and is coupled with the bioaccumulation model for marine methylmercury (BAM3) with ocean biogeochemistry from DARWIN model. We develop a unified scheme that scales methylation by microbe activity and assumes demethylation a function of short wave radiation and temperature. The model result agrees well with currently available observations at the 0-100 m (mod.: 43±52 fM vs obs.: 69±67 fM, 1 fM = 10-15 mol/L), 500 m (360±280 fM vs 340±260 fM), and 1000 m depth (260±170 fM vs 290±210 fM). In the surface ocean, we find the MeHg concentrations are a function of latitude, resulting from photodemethylation. The model reproduces the high concentrations observed over the sub-thermocline of Pacific Subarctic Gyre, which is associated with active microbe activity. On the other hand, both the model and observations suggest low concentrations over oligotrophic regions such as Indian Ocean Gyre. In the tropical oceans, the model predicts the highest MeHg concentrations, consistent with observation, and it is caused by the overlapping high atmospheric deposition and active microbe activities. The model captures the high concentrations in the subsurface of the Arctic and Southern Ocean where low temperature slows down abiotic demethylation. The modeled global average MeHg concentration in phytoplankton is 2.0 ng/g (by wet weight), within the same range of observations. High concentrations are modeled over tropical and high-latitude regions due to the dominance of small sized prochlorococcus and high seawater concentrations

  15. How extreme is extreme hourly precipitation?

    Science.gov (United States)

    Papalexiou, Simon Michael; Dialynas, Yannis G.; Pappas, Christoforos

    2016-04-01

    The importance of accurate representation of precipitation at fine time scales (e.g., hourly), directly associated with flash flood events, is crucial in hydrological design and prediction. The upper part of a probability distribution, known as the distribution tail, determines the behavior of extreme events. In general, and loosely speaking, tails can be categorized in two families: the subexponential and the hyperexponential family, with the first generating more intense and more frequent extremes compared to the latter. In past studies, the focus has been mainly on daily precipitation, with the Gamma distribution being the most popular model. Here, we investigate the behaviour of tails of hourly precipitation by comparing the upper part of empirical distributions of thousands of records with three general types of tails corresponding to the Pareto, Lognormal, and Weibull distributions. Specifically, we use thousands of hourly rainfall records from all over the USA. The analysis indicates that heavier-tailed distributions describe better the observed hourly rainfall extremes in comparison to lighter tails. Traditional representations of the marginal distribution of hourly rainfall may significantly deviate from observed behaviours of extremes, with direct implications on hydroclimatic variables modelling and engineering design.

  16. Optimization with Extremal Dynamics

    International Nuclear Information System (INIS)

    Boettcher, Stefan; Percus, Allon G.

    2001-01-01

    We explore a new general-purpose heuristic for finding high-quality solutions to hard discrete optimization problems. The method, called extremal optimization, is inspired by self-organized criticality, a concept introduced to describe emergent complexity in physical systems. Extremal optimization successively updates extremely undesirable variables of a single suboptimal solution, assigning them new, random values. Large fluctuations ensue, efficiently exploring many local optima. We use extremal optimization to elucidate the phase transition in the 3-coloring problem, and we provide independent confirmation of previously reported extrapolations for the ground-state energy of ±J spin glasses in d=3 and 4

  17. Prenatal methylmercury exposure hampers glutathione antioxidant system ontogenesis and causes long-lasting oxidative stress in the mouse brain

    International Nuclear Information System (INIS)

    Stringari, James; Nunes, Adriana K.C.; Franco, Jeferson L.; Bohrer, Denise; Garcia, Solange C.; Dafre, Alcir L.; Milatovic, Dejan; Souza, Diogo O.; Rocha, Joao B.T.; Aschner, Michael; Farina, Marcelo

    2008-01-01

    During the perinatal period, the central nervous system (CNS) is extremely sensitive to metals, including methylmercury (MeHg). Although the mechanism(s) associated with MeHg-induced developmental neurotoxicity remains obscure, several studies point to the glutathione (GSH) antioxidant system as an important molecular target for this toxicant. To extend our recent findings of MeHg-induced GSH dyshomeostasis, the present study was designed to assess the developmental profile of the GSH antioxidant system in the mouse brain during the early postnatal period after in utero exposure to MeHg. Pregnant mice were exposed to different doses of MeHg (1, 3 and 10 mg/l, diluted in drinking water, ad libitum) during the gestational period. After delivery, pups were killed at different time points - postnatal days (PND) 1, 11 and 21 - and the whole brain was used for determining biochemical parameters related to the antioxidant GSH system, as well as mercury content and the levels of F 2 -isoprostane. In control animals, cerebral GSH levels significantly increased over time during the early postnatal period; gestational exposure to MeHg caused a dose-dependent inhibition of this developmental event. Cerebral glutathione peroxidase (GPx) and glutathione reductase (GR) activities significantly increased over time during the early postnatal period in control animals; gestational MeHg exposure induced a dose-dependent inhibitory effect on both developmental phenomena. These adverse effects of prenatal MeHg exposure were corroborated by marked increases in cerebral F 2 -isoprostanes levels at all time points. Significant negative correlations were found between F 2 -isoprostanes and GSH, as well as between F 2 -isoprostanes and GPx activity, suggesting that MeHg-induced disruption of the GSH system maturation is related to MeHg-induced increased lipid peroxidation in the pup brain. In utero MeHg exposure also caused a dose-dependent increase in the cerebral levels of mercury at

  18. Classifying Returns as Extreme

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    2014-01-01

    I consider extreme returns for the stock and bond markets of 14 EU countries using two classification schemes: One, the univariate classification scheme from the previous literature that classifies extreme returns for each market separately, and two, a novel multivariate classification scheme tha...

  19. Methylmercury in fish from the South China Sea: geographical distribution and biomagnification.

    Science.gov (United States)

    Zhu, Aijia; Zhang, Wei; Xu, Zhanzhou; Huang, Liangmin; Wang, Wen-Xiong

    2013-12-15

    We conducted a large-scale investigation of methylmercury (MeHg) in a total of 628 marine wild fish covering 46 different species collected from the South China Sea between 2008 and 2009. Biological and ecological characteristics such as size (length and wet weight), feeding habit, habitat, and stable isotope (δ(15)N) were examined to explain MeHg bioaccumulation in marine fish and their geographical distribution. MeHg levels in the muscle tissues of the 628 individuals ranged from 0.010 to 1.811 μg/g dry wt. Log10MeHg concentration was significantly related to their length and wet weight. Feeding habit and habitat were the primary factors influencing MeHg bioaccumulation. Demersal fish were more likely to be contaminated with MeHg than the epipelagic and mesopelagic varieties. Linear relationships were obtained between Log10(MeHg) and δ(15)N only for one location, indicating that biomagnification was site-specific. Results from this study suggest that dietary preference and trophic structure were the main factors affecting MeHg bioaccumulation in marine fish from the South China Sea. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Methylmercury Induced Neurotoxicity and the Influence of Selenium in the Brains of Adult Zebrafish (Danio rerio

    Directory of Open Access Journals (Sweden)

    Josef Daniel Rasinger

    2017-03-01

    Full Text Available The neurotoxicity of methylmercury (MeHg is well characterised, and the ameliorating effects of selenium have been described. However, little is known about the molecular mechanisms behind this contaminant-nutrient interaction. We investigated the influence of selenium (as selenomethionine, SeMet and MeHg on mercury accumulation and protein expression in the brain of adult zebrafish (Danio rerio. Fish were fed diets containing elevated levels of MeHg and/or SeMet in a 2 × 2 full factorial design for eight weeks. Mercury concentrations were highest in the brain tissue of MeHg-exposed fish compared to the controls, whereas lower levels of mercury were found in the brain of zebrafish fed both MeHg and SeMet compared with the fish fed MeHg alone. The expression levels of proteins associated with gap junction signalling, oxidative phosphorylation, and mitochondrial dysfunction were significantly (p < 0.05 altered in the brain of zebrafish after exposure to MeHg and SeMet alone or in combination. Analysis of upstream regulators indicated that these changes were linked to the mammalian target of rapamycin (mTOR pathways, which were activated by MeHg and inhibited by SeMet, possibly through a reactive oxygen species mediated differential activation of RICTOR, the rapamycin-insensitive binding partner of mTOR.

  1. Methylmercury Exposure and Health Effects from Rice and Fish Consumption: A Review

    Directory of Open Access Journals (Sweden)

    Ping Li

    2010-06-01

    Full Text Available Methylmercury (MeHg is highly toxic, and its principal target tissue in humans is the nervous system, which has made MeHg intoxication a public health concern for many decades. The general population is primarily exposed to MeHg through consumption of contaminated fish and marine mammals, but recent studies have reported high levels of MeHg in rice and confirmed that in China the main human exposure to MeHg is related to frequent rice consumption in mercury (Hg polluted areas. This article reviews the progress in the research on MeHg accumulation in rice, human exposure and health effects, and nutrient and co-contaminant interactions. Compared with fish, rice is of poor nutritional quality and lacks specific micronutrients identified as having health benefits (e.g., n-3 long chain polyunsaturated fatty acid, selenium, essential amino acids. The effects of these nutrients on the toxicity of MeHg should be better addressed in future epidemiologic and clinical studies. More emphasis should be given to assessing the health effects of low level MeHg exposure in the long term, with appropriate recommendations, as needed, to reduce MeHg exposure in the rice-eating population.

  2. Bioaccumulation of methylmercury in fish tissue from the Roosevelt River, Southwestern Amazon basin

    Directory of Open Access Journals (Sweden)

    Marcelo Rodrigues dos Anjos

    2016-06-01

    Full Text Available Mercury is a major pollutant in the Amazon River system, and its levels in fish and human hair are usually above the limit recommended by health agencies. The objective of this study was to analyze the methylmercury (MeHg concentration in fish tissue from the Roosevelt River. The river's water velocity, depth, pH, temperature, electrical conductivity, dissolved oxygen and substrate type were measured, and fifty specimens distributed in 14 fish species were collected. A total of 64.3% of the sampled species were of the order Characiform and 71.4% of the species were carnivores. Fifty percent of the species had MeHg concentrations above threshold limit (Hg-T 0.5 mg kg-1 established for food by the World Health Organization. Cichla monoculus had the highest value of MeHg (2.45 mg kg-1. The MeHg concentration in fish varied according to dietary habits. The study also found bioaccumulation of MeHg in fish tissue in the following descending order: carnivorous > detritivorous > frugivore. Low significant correlations were found between fish weight or length and MeHg. Further studies on MeHg contamination are recommended in tissues of fish consumed in human riverine communities in the Roosevelt River Basin.

  3. Determination of total mercury and methylmercury in the head hair of pregnant Vietnamese women

    International Nuclear Information System (INIS)

    Nguyen Tac Anh; Ho Manh Dung; Pham Hoang Ha; Nguyen Thuy Sy; Le Tat Mua

    1995-01-01

    Neutron Activation Analysis (NAA), including both the non-destructive (Instrumental NAA) and destructive (Radiochemical NAA) forms, is used as the principal technique to determine total mercury (T-Hg) and methylmercury (MeHg) in samples of human head hair. Head hair samples taken from pregnant women has been the focus for sample collection in this project. In addition, a special population group (Buddhist monks) and a normal population (control) group have also been selected for study. The defined population groups are residing in distinct regions which represent highland, coastal and industrial areas in Vietnam. Preliminary results from the determination of T-Hg and MeHg in hair samples from the defined groups indicate that the consumption of fish and seafood products is the main source of intake of MeHg; this agrees with the results from other investigators. The mean T-Hg in human hair samples from Ho Chi Minh City (an industrial region) was statistically higher than the corresponding mean values from samples taken in Dalat and Nha Trang cities, which suggest that industrial activities may be discharging an appreciable amount of mercury into the environment around Ho Chi Minh City. (author)

  4. Accumulation of total mercury and methylmercury in rice plants collected from different mining areas in China

    International Nuclear Information System (INIS)

    Meng, Mei; Li, Bing; Shao, Jun-juan; Wang, Thanh; He, Bin; Shi, Jian-bo; Ye, Zhi-hong; Jiang, Gui-bin

    2014-01-01

    A total of 155 rice plants were collected from ten mining areas in three provinces of China (Hunan, Guizhou and Guangdong), where most of mercury (Hg) mining takes place in China. During the harvest season, whole rice plants were sampled and divided into root, stalk and leaf, husk and seed (brown rice), together with soil from root zone. Although the degree of Hg contamination varied significantly among different mining areas, rice seed showed the highest ability for methylmercury (MeHg) accumulation. Both concentrations of total mercury (THg) and MeHg in rice plants were significantly correlated with Hg levels in soil, indicating soil is still an important source for both inorganic mercury (IHg) and MeHg in rice plants. The obvious discrepancy between the distribution patterns of THg and MeHg reflected different pathways of IHg and MeHg accumulation. Water soluble Hg may play more important role in MeHg accumulation in rice plants. -- Highlights: • Distribution patterns indicated different pathways of IHg and MeHg accumulation. • Soil is an important source for both THg and MeHg to rice plants. • Water soluble Hg may play more important role in MeHg accumulation in rice plants. -- The distribution patterns indicate different pathways of IHg and MeHg accumulation in rice plants

  5. Economic benefits of methylmercury exposure control in Europe: Monetary value of neurotoxicity prevention

    DEFF Research Database (Denmark)

    Bellanger, Martine; Pichery, Céline; Aerts, Dominique

    2013-01-01

    BACKGROUND: Due to global mercury pollution and the adverse health effects of prenatal exposure to methylmercury (MeHg), an assessment of the economic benefits of prevented developmental neurotoxicity is necessary for any cost-benefit analysis. METHODS: Distributions of hair-Hg concentrations among...... with a slope of 0.465 Intelligence Quotient (IQ) point reduction per μg/g increase in the maternal hair-Hg concentration during pregnancy, assuming no deficits below a hair-Hg limit of 0.58 μg/g thought to be safe. A logarithmic IQ response was used in sensitivity analyses. The estimated IQ benefit cost.......58 μg/g, and about 200,000 births exceed a higher limit of 2.5 μg/g proposed by the World Health Organization (WHO). The total annual benefits of exposure prevention within the EU were estimated at more than 600,000 IQ points per year, corresponding to a total economic benefit between €8,000 million...

  6. Protective Effect of Prolactin against Methylmercury-Induced Mutagenicity and Cytotoxicity on Human Lymphocytes

    Directory of Open Access Journals (Sweden)

    Liz Carmem Silva-Pereira

    2014-09-01

    Full Text Available Mercury exhibits cytotoxic and mutagenic properties as a result of its effect on tubulin. This toxicity mechanism is related to the production of free radicals that can cause DNA damage. Methylmercury (MeHg is one of the most toxic of the mercury compounds. It accumulates in the aquatic food chain, eventually reaching the human diet. Several studies have demonstrated that prolactin (PRL may be differently affected by inorganic and organic mercury based on interference with various neurotransmitters involved in the regulation of PRL secretion. This study evaluated the cytoprotective effect of PRL on human lymphocytes exposed to MeHg in vitro, including observation of the kinetics of HL-60 cells (an acute myeloid leukemia lineage treated with MeHg and PRL at different concentrations, with both treatments with the individual compounds and combined treatments. All treatments with MeHg produced a significant increase in the frequency of chromatid gaps, however, no significant difference was observed in the chromosomal breaks with any treatment. A dose-dependent increase in the mitotic index was observed for treatments with PRL, which also acts as a co-mitogenic factor, regulating proliferation by modulating the expression of genes that are essential for cell cycle progression and cytoskeleton organization. These properties contribute to the protective action of PRL against the cytotoxic and mutagenic effects of MeHg.

  7. 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.

  8. Protective Effect of Prolactin against Methylmercury-Induced Mutagenicity and Cytotoxicity on Human Lymphocytes

    Science.gov (United States)

    Silva-Pereira, Liz Carmem; da Rocha, Carlos Alberto Machado; Cunha, Luiz Raimundo Campos da Silva e; da Costa, Edmar Tavares; Guimarães, Ana Paula Araújo; Pontes, Thais Brilhante; Diniz, Domingos Luiz Wanderley Picanço; Leal, Mariana Ferreira; Moreira-Nunes, Caroline Aquino; Burbano, Rommel Rodríguez

    2014-01-01

    Mercury exhibits cytotoxic and mutagenic properties as a result of its effect on tubulin. This toxicity mechanism is related to the production of free radicals that can cause DNA damage. Methylmercury (MeHg) is one of the most toxic of the mercury compounds. It accumulates in the aquatic food chain, eventually reaching the human diet. Several studies have demonstrated that prolactin (PRL) may be differently affected by inorganic and organic mercury based on interference with various neurotransmitters involved in the regulation of PRL secretion. This study evaluated the cytoprotective effect of PRL on human lymphocytes exposed to MeHg in vitro, including observation of the kinetics of HL-60 cells (an acute myeloid leukemia lineage) treated with MeHg and PRL at different concentrations, with both treatments with the individual compounds and combined treatments. All treatments with MeHg produced a significant increase in the frequency of chromatid gaps, however, no significant difference was observed in the chromosomal breaks with any treatment. A dose-dependent increase in the mitotic index was observed for treatments with PRL, which also acts as a co-mitogenic factor, regulating proliferation by modulating the expression of genes that are essential for cell cycle progression and cytoskeleton organization. These properties contribute to the protective action of PRL against the cytotoxic and mutagenic effects of MeHg. PMID:25247425

  9. NAD+ Supplementation Attenuates Methylmercury Dopaminergic and Mitochondrial Toxicity in Caenorhabditis Elegans

    Science.gov (United States)

    Caito, Samuel W.; Aschner, Michael

    2016-01-01

    Methylmercury (MeHg) is a neurotoxic contaminant of our fish supply that has been linked to dopaminergic (DAergic) dysfunction that characterizes Parkinson’s disease. We have previously shown that MeHg causes both morphological and behavioral changes in the Caenorhabditis elegans DAergic neurons that are associated with oxidative stress. We were therefore interested in whether the redox sensitive cofactor nicotinamide adenine dinucleotide (NAD+) may be affected by MeHg and whether supplementation of NAD + may prevent MeHg-induced toxicities. Worms treated with MeHg showed depletion in cellular NAD + levels, which was prevented by NAD + supplementation prior to MeHg treatment. NAD + supplementation also prevented DAergic neurodegeneration and deficits in DAergic-dependent behavior upon MeHg exposure. In a mutant worm line that cannot synthesize NAD + from nicotinamide, MeHg lethality and DAergic behavioral deficits were more sensitive to MeHg than wildtype worms, demonstrating the importance of NAD + in MeHg toxicity. In wildtype worms, NAD + supplementation provided protection from MeHg-induced oxidative stress and mitochondrial dysfunction. These data show the importance of NAD + levels in the response to MeHg exposure. NAD + supplementation may be beneficial for MeHg-induced toxicities and preventing cellular damage involved in Parkinson’s disease. PMID:26865665

  10. Methylmercury bioaccumulation in stream food webs declines with increasing primary production

    Science.gov (United States)

    Walters, David; D.F. Raikow,; C.R. Hammerschmidt,; M.G. Mehling,; A. Kovach,; J.T. Oris,

    2015-01-01

    Opposing hypotheses posit that increasing primary productivity should result in either greater or lesser contaminant accumulation in stream food webs. We conducted an experiment to evaluate primary productivity effects on MeHg accumulation in stream consumers. We varied light for 16 artificial streams creating a productivity gradient (oxygen production =0.048–0.71 mg O2 L–1 d–1) among streams. Two-level food webs were established consisting of phytoplankton/filter feeding clam, periphyton/grazing snail, and leaves/shredding amphipod (Hyalella azteca). Phytoplankton and periphyton biomass, along with MeHg removal from the water column, increased significantly with productivity, but MeHg concentrations in these primary producers declined. Methylmercury concentrations in clams and snails also declined with productivity, and consumer concentrations were strongly correlated with MeHg concentrations in primary producers. Heterotroph biomass on leaves, MeHg in leaves, and MeHg in Hyalella were unrelated to stream productivity. Our results support the hypothesis that contaminant bioaccumulation declines with stream primary production via the mechanism of bloom dilution (MeHg burden per cell decreases in algal blooms), extending patterns of contaminant accumulation documented in lakes to lotic systems.

  11. Beaver ponds increase methylmercury concentrations in Canadian shield streams along vegetation and pond-age gradients.

    Science.gov (United States)

    Roy, Virginie; Amyot, Marc; Carignan, Richard

    2009-08-01

    Beaver impoundments flood forested areas and may be important production sites for methylmercury (MeHg) because of the resulting enhanced microbial activity and oxygen depletion. The influence of 17 beaver impoundments on streamwater chemistry (total mercury (THg), MeHg, nutrients, cations, and anions)] was investigated by sampling sites located along vegetation and pond-age gradients in southwestern Quebec (Canada). Recently inundated beaver ponds (beaver ponds as suggested by depletions of dissolved oxygen, sulfate and nitrite-nitrate concentrations, and increases in nutrients (e.g., dissolved organic carbon, total phosphorus, and total nitrogen) in outlets compared to inlets. Acidic waters at coniferous sites may have stimulated more MeHg production than in mixed woodland regions. Lower methylation efficiencies in older ponds (> 20 years old) may be due to the degradation of less labile organic matter as ponds age. Beavers actively alter watersheds by building impoundments, and our findings indicate that this landscape disturbance may be a significant source of MeHg to downstream water bodies.

  12. Methylmercury inhibits gap junctional intercellular communication in primary cultures of rat proximal tubular cells

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Minoru; Sumi, Yawara [Department of Chemistry, St. Marianna University School of Medicine, Kawasagi (Japan); Kujiraoka, Toru [Department of Physiology, St. Marianna University School of Medicine, Kawasagi (Japan); Hara, Masayuki [Department of Anatomy, St. Marianna University School of Medicine, Kawasagi (Japan); Nakazawa, Hirokazu [Department of Chemistry, Faculty of Sciences, Meisei University (Japan)

    1998-03-01

    Methylmercury (MeHg) causes renal injury in addition to central and peripheral neuropathy. To clarify the mechanism of nephrotoxicity by MeHg, we investigated the effect of this compound on intercellular communication through gap junction channels in primary cultures of rat renal proximal tubular cells. Twenty minutes after exposure to 30 {mu}M MeHg, gap junctional intercellular communication (GJIC), which was assessed by dye coupling, was markedly inhibited before appearance of cytotoxicity. When the medium containing MeHg was exchanged with MeHg-free medium, dye coupling recovered abruptly. However, the dye-coupling was abolished again 30 min after replacement with control medium, and the cells were damaged. Intracellular calcium concentration, [Ca{sup 2+}]{sub i}, which modulates the function of gap junctions, significantly increased following exposure of the cells to 30 {mu}M MeHg and returned to control level following replacement with MeHg-free medium. These results suggest that the inhibiting effect of MeHg on GJIC is related to the change in [Ca{sup 2+}]{sub i}, and may be involved in the pathogenesis of renal dysfunction. (orig.) With 5 figs., 23 refs.

  13. Gene expression changes in female zebrafish (Danio rerio) brain in response to acute exposure to methylmercury

    Science.gov (United States)

    Richter, Catherine A.; Garcia-Reyero, Natàlia; Martyniuk, Chris; Knoebl, Iris; Pope, Marie; Wright-Osment, Maureen K.; Denslow, Nancy D.; Tillitt, Donald E.

    2011-01-01

    Methylmercury (MeHg) is a potent neurotoxicant and endocrine disruptor that accumulates in aquatic systems. Previous studies have shown suppression of hormone levels in both male and female fish, suggesting effects on gonadotropin regulation in the brain. The gene expression profile in adult female zebrafish whole brain induced by acute (96 h) MeHg exposure was investigated. Fish were exposed by injection to 0 or 0.5(mu or u)g MeHg/g. Gene expression changes in the brain were examined using a 22,000-feature zebrafish microarray. At a significance level of p

  14. Assessing exposure risks for freshwater tilapia species posed by mercury and methylmercury.

    Science.gov (United States)

    Cheng, Yi-Hsien; Lin, Yi-Jun; You, Shu-Han; Yang, Ying-Fei; How, Chun Ming; Tseng, Yi-Ting; Chen, Wei-Yu; Liao, Chung-Min

    2016-08-01

    Waterborne and dietborne exposures of freshwater fish to mercury (Hg) in the forms of inorganic (Hg(II)) and organic (methylmercury or MeHg) affect their growth, development, and reproduction. However, an integrated mechanistic risk model framework to predict the impact of Hg(II)/MeHg on freshwater fish is lacking. Here, we integrated biokinetic, physiological and biogeographic data to calibrate and then establish key risk indices-hazardous quotient and exceedance risk-for freshwater tilapia species across geographic ranges of several major rivers in Taiwan. We found that Hg(II) burden was highest in kidney followed by gill, intestine, liver, blood, and muscle. Our results showed that Hg was less likely to pose mortality risk (mortality rate less than 5 %) for freshwater tilapia species. However, Hg is likely to pose the potential hazard to aquatic environments constrained by safety levels for aquatic organisms. Sensitivity analysis showed that amount of Hg accumulated in tilapia was most influenced by sediment uptake rate. Our approach opens up new possibilities for predicting future fish population health with the impacts of continued Hg exposure to provide information on which fish are deemed safe for human consumption.

  15. Altered pairing behaviour and reproductive success in white ibises exposed to environmentally relevant concentrations of methylmercury.

    Science.gov (United States)

    Frederick, Peter; Jayasena, Nilmini

    2011-06-22

    Methylmercury (MeHg) is the most biologically available and toxic form of mercury, and can act as a powerful teratogen, neurotoxin and endocrine disruptor in vertebrates. However, mechanisms of endocrine impairment and net effects on demography of biota are poorly understood. Here, we report that experimental exposure of an aquatic bird over 3 years to environmentally relevant dietary MeHg concentrations (0.05-0.3 ppm wet weight) resulted in dose-related increases in male-male pairing behaviour (to 55% of males), and decreases in egg productivity (to 30%). Dosed males showed decreased rates of key courtship behaviours, and were approached less by courting females in comparison to control males. Within dosed groups, homosexual males showed a similar reduction when compared with dosed heterosexual males. We found an average 35 per cent decrease in fledgling production in high-dose birds over the study duration. These results are of interest because (i) MeHg exposure is experimentally tied to demographically important reproductive deficits, (ii) these effects were found at low, chronic exposure levels commonly experienced by wildlife, and (iii) effects on reproductive behaviour and sexual preference mediated by endocrine disruption represent a novel and probably under-reported mechanism by which contaminants may influence wild populations of birds.

  16. Shallow methylmercury production in the marginal sea ice zone of the central Arctic Ocean.

    Science.gov (United States)

    Heimbürger, Lars-Eric; Sonke, Jeroen E; Cossa, Daniel; Point, David; Lagane, Christelle; Laffont, Laure; Galfond, Benjamin T; Nicolaus, Marcel; Rabe, Benjamin; van der Loeff, Michiel Rutgers

    2015-05-20

    Methylmercury (MeHg) is a neurotoxic compound that threatens wildlife and human health across the Arctic region. Though much is known about the source and dynamics of its inorganic mercury (Hg) precursor, the exact origin of the high MeHg concentrations in Arctic biota remains uncertain. Arctic coastal sediments, coastal marine waters and surface snow are known sites for MeHg production. Observations on marine Hg dynamics, however, have been restricted to the Canadian Archipelago and the Beaufort Sea (Ocean (79-90 °N) profiles for total mercury (tHg) and MeHg. We find elevated tHg and MeHg concentrations in the marginal sea ice zone (81-85 °N). Similar to other open ocean basins, Arctic MeHg concentration maxima also occur in the pycnocline waters, but at much shallower depths (150-200 m). The shallow MeHg maxima just below the productive surface layer possibly result in enhanced biological uptake at the base of the Arctic marine food web and may explain the elevated MeHg concentrations in Arctic biota. We suggest that Arctic warming, through thinning sea ice, extension of the seasonal sea ice zone, intensified surface ocean stratification and shifts in plankton ecodynamics, will likely lead to higher marine MeHg production.

  17. Tributyltin chloride increases phenylephrine-induced contraction and vascular stiffness in mesenteric resistance arteries from female rats

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro Júnior, Rogério Faustino, E-mail: rogeriofaustinoribeiro@hotmail.com [Department of Physiological Sciences, Federal University of Espirito Santo, Vitoria, ES (Brazil); Marques, Vinicius Bermond; Nunes, Dieli Oliveira; Ronconi, Karoline de Sousa [Department of Physiological Sciences, Federal University of Espirito Santo, Vitoria, ES (Brazil); Araújo, Julia F.P. de [Department of Morphology, Federal University of Espírito Santo (Brazil); Rodrigues, Paula Lopes; Padilha, Alessandra Simão; Vassallo, Dalton Valentim [Department of Physiological Sciences, Federal University of Espirito Santo, Vitoria, ES (Brazil); Graceli, Jones B. [Department of Morphology, Federal University of Espírito Santo (Brazil); Stefanon, Ivanita [Department of Physiological Sciences, Federal University of Espirito Santo, Vitoria, ES (Brazil)

    2016-03-15

    Tributyltin chloride (TBT) is an organotin compound that reduces estrogen levels in female rats. We aimed to investigate the effects of TBT exposure on vascular tonus and vascular remodelling in the resistance arteries of female rats. Rats were treated daily with TBT (500 ng/kg) for 15 days. TBT did not change arterial blood pressure but did modify some morpho-physiological parameters of third-order mesenteric resistance arteries in the following ways: (1) decreased lumen and external diameters; (2) increased wall/lm ratio and wall thickness; (3) decreased distensibility and increased stiffness; (4) increased collagen deposition; and (5) increased pulse wave velocity. TBT exposure increased the phenylephrine-induced contractile response in mesenteric resistance arteries. However, vasodilatation responses induced by acetylcholine and sodium nitroprusside were not modified by TBT. It is suggested that TBT exposure reduces vascular nitric oxide (NO) production, because:(1) L-NAME incubation did not cause a leftward shift in the concentration–response curve for phenylephrine; (2) both eNOS protein expression; (3) in situ NO production were reduced. Incubation with L-NAME; and (4) SOD shifted the phenylephrine response curve to the left in TBT rats. Tiron, catalase, ML-171 and VAS2870 decreased vascular reactivity to phenylephrine only in TBT rats. Moreover, increased superoxide anion production was observed in the mesenteric resistance arteries of TBT rats accompanied by an increase in gp91phox, catalase, AT{sub 1} receptor and total ERK1/2 protein expression. In conclusion, these findings show that TBT induced alterations are most likely due to a reduction of NO production combined with increased O{sub 2}{sup −} production derived from NADPH oxidase and ERK1/2 activation. These findings offer further evidence that TBT is an environmental risk factor for cardiovascular disease. - Highlights: • Tributyltin chloride reduces estrogen levels in female rats.

  18. Methylmercury disrupts the balance between phosphorylated and non-phosphorylated cofilin in primary cultures of mice cerebellar granule cells A proteomic study

    International Nuclear Information System (INIS)

    Vendrell, Iolanda; Carrascal, Montserrat; Campos, Francisco; Abian, Joaquin; Sunol, Cristina

    2010-01-01

    Methylmercury is an environmental contaminant that is particularly toxic to the developing central nervous system; cerebellar granule neurons are especially vulnerable. Here, primary cultures of cerebellar granule cells (CGCs) were continuously exposed to methylmercury for up to 16 days in vitro (div). LC50 values were 508 ± 199, 345 ± 47, and 243 ± 45 nM after exposure for 6, 11, and 16 div, respectively. Proteins from cultured mouse CGCs were separated by 2DE. Seventy-one protein spots were identified by MALDI-TOF PMF and MALDI-TOF/TOF sequencing. Prolonged exposure to a subcytotoxic concentration of methylmercury significantly increased non-phosphorylated cofilin both in cell protein extracts (1.4-fold; p < 0.01) and in mitochondrial-enriched fractions (1.7-fold; p < 0.01). The decrease in P-cofilin induced by methylmercury was concentration-dependent and occurred after different exposure times. The percentage of P-cofilin relative to total cofilin significantly decreased to 49 ± 13% vs. control cells after exposure to 300 nM methylmercury for 5 div. The balance between the phosphorylated and non-phosphorylated form of cofilin regulates actin dynamics and facilitates actin filament turnover. Filamentous actin dynamics and reorganization are responsible of neuron shape change, migration, polarity formation, regulation of synaptic structures and function, and cell apoptosis. An alteration of the complex regulation of the cofilin phosphorylation/dephosphorylation pathway could be envisaged as an underlying mechanism compatible with reported signs of methylmercury-induced neurotoxicity.

  19. Extremal surface barriers

    International Nuclear Information System (INIS)

    Engelhardt, Netta; Wall, Aron C.

    2014-01-01

    We present a generic condition for Lorentzian manifolds to have a barrier that limits the reach of boundary-anchored extremal surfaces of arbitrary dimension. We show that any surface with nonpositive extrinsic curvature is a barrier, in the sense that extremal surfaces cannot be continuously deformed past it. Furthermore, the outermost barrier surface has nonnegative extrinsic curvature. Under certain conditions, we show that the existence of trapped surfaces implies a barrier, and conversely. In the context of AdS/CFT, these barriers imply that it is impossible to reconstruct the entire bulk using extremal surfaces. We comment on the implications for the firewall controversy

  20. Psychomotor Ability in Children Prenatally Exposed to Methylmercury: The 18-Month Follow-Up of Tohoku Study of Child Development.

    Science.gov (United States)

    Tatsuta, Nozomi; Murata, Katsuyuki; Iwai-Shimada, Miyuki; Yaginuma-Sakurai, Kozue; Satoh, Hiroshi; Nakai, Kunihiko

    2017-05-01

    Fish contain nutrients essential to the developing fetal brain, but they are contaminated with methylmercury. The Tohoku Study of Child Development, now underway in the Sanriku coastal area of Miyagi prefecture, Japan, follows mother-child pairs to examine the risks and benefits of fish consumption during pregnancy, especially the effects of prenatal exposures to methylmercury, selenium, and docosahexaenoic acid (DHA) on child neurodevelopment. Children aged 18 months were administered the Bayley Scales of Infant Development second edition (BSID-II) and Kyoto Scale of Psychological Development (KSPD) in 2004-2008. Complete data of cord-blood total mercury (THg), cord-plasma selenium, maternal-plasma DHA, the above test scores, and confounders for 566 mother-child pairs were available. The median cord-blood THg level was 15.7 (range, 2.7-96.1) ng/g. Since the BSID-II and KSPD scores were significantly lower in the 285 boys than in the 281 girls, analyses were conducted separately. The Psychomotor Development Index (PDI) of BSID-II was significantly correlated with cord-blood THg only in the boys, and significance of the association remained unchanged after adjusting for possible confounders; i.e., a 10-fold increase in cord-blood THg was associated with a 8.3-point decrease in the score of the PDI. Other significant correlations of THg were not seen in the boys or girls. Selenium and DHA showed no significant correlations with the BSID-II or KSPD scores in either sex. In conclusion, intrauterine methylmercury exposure may affect psychomotor development, and boys appear to be more vulnerable to the exposure than girls.

  1. Alteration of putative amino acid levels and morphological findings in neural tissues of methylmercury-intoxicated mice

    Energy Technology Data Exchange (ETDEWEB)

    Hirayama, K.; Inouye, M.; Fujisaki, T.

    1985-04-01

    Methylmercury chloride was administered PO to male Kud:ddY mice at a dose of 5 mg/kg/day for 20 days. The contents of taurine, aspartate, glutamate, glycine, and ..gamma..-aminobutyric acid were determined in tissue and crude synaptosomal (P/sub 2/) fraction of cerebellum, cerebral cortex, and spinal cord of methylmercury-treated mice with or without ataxia. In the cerebellum of ataxic mice, increased levels of taurine and glycine were found in the tissue and P/sub 2/ fraction, and increased levels of glutamate were found in the P/sub 2/ fraction. In the cerebral cortex, the levels of ..gamma..-aminobutylic acid decreased in the tissue and in the P/sub 2/ fraction of ataxic mice, but increased levels were found in the tissue of non-ataxic mice. A decreased asparate level in the cerebral cortex of ataxic mice and an increased taurine level in the cerebral cortex of non-ataxic mice were also found. In the spinal cord of ataxic mice, taurine increased in the tissue and in the P/sub 2/ fraction. Glutamate level decreased in the spinal cord of ataxic mice, but increased in the P/sub 2/ fraction of non-ataxic mice. Increased glycine levels in the P/sub 2/ fraction of the spinal cord were also found in non-axtaxic mice. Histologically, some degenerative changes were demonstrated in the cerebral and cerebellar cortices of ataxic mice. Such changes were also present to a mild degree in non-ataxic mice. In conclusion, methylmercury treatment altered the levels of putative neurotransmitter amino acids in neutral tissue of mice. These alterations might be caused by specific neural cell dysfunction and could be related to the appearance of ataxia.

  2. The Environmental Pollutant Tributyltin Chloride Disrupts the Hypothalamic-Pituitary-Adrenal Axis at Different Levels in Female Rats.

    Science.gov (United States)

    Merlo, Eduardo; Podratz, Priscila L; Sena, Gabriela C; de Araújo, Julia F P; Lima, Leandro C F; Alves, Izabela S S; Gama-de-Souza, Letícia N; Pelição, Renan; Rodrigues, Lívia C M; Brandão, Poliane A A; Carneiro, Maria T W D; Pires, Rita G W; Martins-Silva, Cristina; Alarcon, Tamara A; Miranda-Alves, Leandro; Silva, Ian V; Graceli, Jones B

    2016-08-01

    Tributyltin chloride (TBT) is an environmental contaminant that is used as a biocide in antifouling paints. TBT has been shown to induce endocrine-disrupting effects. However, studies evaluating the effects of TBT on the hypothalamus-pituitary-adrenal (HPA) axis are especially rare. The current study demonstrates that exposure to TBT is critically responsible for the improper function of the mammalian HPA axis as well as the development of abnormal morphophysiology in the pituitary and adrenal glands. Female rats were treated with TBT, and their HPA axis morphophysiology was assessed. High CRH and low ACTH expression and high plasma corticosterone levels were detected in TBT rats. In addition, TBT leads to an increased in the inducible nitric oxide synthase protein expression in the hypothalamus of TBT rats. Morphophysiological abnormalities, including increases in inflammation, a disrupted cellular redox balance, apoptosis, and collagen deposition in the pituitary and adrenal glands, were observed in TBT rats. Increases in adiposity and peroxisome proliferator-activated receptor-γ protein expression in the adrenal gland were observed in TBT rats. Together, these data provide in vivo evidence that TBT leads to functional dissociation between CRH, ACTH, and costicosterone, which could be associated an inflammation and increased of inducible nitric oxide synthase expression in hypothalamus. Thus, TBT exerts toxic effects at different levels on the HPA axis function.

  3. Morphological and transcriptomic effects of endocrine modulators on the gonadal differentiation of chicken embryos: The case of tributyltin (TBT).

    Science.gov (United States)

    Scheider, Jessica; Afonso-Grunz, Fabian; Jessl, Luzie; Hoffmeier, Klaus; Winter, Peter; Oehlmann, Jörg

    2018-03-01

    Morphological malformations induced by tributyltin (TBT) exposure during embryonic development have already been characterized in various taxonomic groups, but, nonetheless, the molecular processes underlying these changes remain obscure. The present study provides the first genome-wide screening for differentially expressed genes that are linked to morphological alterations of gonadal tissue from chicken embryos after exposure to TBT. We applied a single injection of TBT (between 0.5 and 30 pg as Sn/g egg) into incubated fertile eggs to simulate maternal transfer of the endocrine disruptive compound. Methyltestosterone (MT) served as a positive control (30 pg/g egg). After 19 days of incubation, structural features of the gonads as well as genome-wide gene expression profiles were assessed simultaneously. TBT induced significant morphological and histological malformations of gonadal tissue from female embryos that show a virilization of the ovaries. This phenotypical virilization was mirrored by altered expression profiles of sex-dependent genes. Among these are several transcription and growth factors (e.g. FGF12, CTCF, NFIB), whose altered expression might serve as a set of markers for early identification of endocrine active chemicals that affect embryonic development by transcriptome profiling without the need of elaborate histological analyses. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  4. Protein phosphatases 2A as well as reactive oxygen species involved in tributyltin-induced apoptosis in mouse livers.

    Science.gov (United States)

    Zhang, Yali; Chen, Yonggang; Sun, Lijun; Liang, Jing; Guo, Zonglou; Xu, Lihong

    2014-02-01

    Tributyltin (TBT), a highly toxic environmental contaminant, has been shown to induce caspase-3-dependent apoptosis in human amniotic cells through protein phosphatase 2A (PP2A) inhibition and consequent JNK activation. This in vivo study was undertaken to further verify the results derived from our previous in vitro study. Mice were orally dosed with 0, 10, 20, and 60 mg/kg of body weight TBT, and levels of PP2A, reactive oxygen species (ROS), mitogen-activated protein kinase (MAPK), Bax/Bcl-2, and caspase-3 were detected in the mouse livers. Apoptosis was also evaluated using the TUNEL assay. The results showed that PP2A activity was inhibited, ROS levels were elevated, and MAPKs including ERK, JNK, and p38 were activated in mouse livers treated with the highest dose of TBT. Additionally, the ratio of Bax/Bcl-2 was increased, caspase-3 was activated, and apoptosis in mouse livers could be detected in the highest dose group. Therefore, a possible signaling pathway in TBT-induced apoptosis in mouse livers involves PP2A inhibition and ROS elevation serving a pivotal function as upstream activators of MAPKs; activation of MAPKs in turn leads to an increase in the Bax/Bcl-2 ratio, ultimately leading to the activation of caspase-3. The results give a comprehensive and novel description of the mechanism of TBT-induced toxicity. Copyright © 2011 Wiley Periodicals, Inc., A Wiley Company.

  5. Toxicity of Tributyltin in Juvenile Common Carp (Cyprinus Carpio): Physiological Responses, Hepatic Gene Expression, and Stress Protein Profiling.

    Science.gov (United States)

    Li, Zhi-Hua; Zhong, Li-Qiao; Mu, Wei-Na; Wu, Yan-Hua

    2016-02-01

    In this study, the effects of tributyltin (TBT) on biochemical parameters (antioxidant responses and Na(+) -K(+) -ATPase) in different tissues were investigated by using juvenile common carp (Cyprinus Carpio) as well as growth and ion regulation-related genes expression and stress-related proteins profiling in fish liver. Oxidative stress indices and Na(+) -K(+) -ATPase showed tissues-specific responses in fish exposed to different TBT concentrations. All tested genes related to GH/IGF-I axis and ion-regulation were significantly induced in the TBT group with lower concentrations (except for the igfbp3 in 10 μg/L) and were inhibited in 20 μg/L. In addition, the profiling of two proteins Hsp 70 and MT were increasing in a dose-dependent manner under TBT stress. In short, TBT-induced biochemical and molecular responses in different tissues were reflected in the measured parameters in the test. On the basis of TBT residue levels in the natural environment, more long-term experiments at lower concentrations will be necessary in the future. © 2015 Wiley Periodicals, Inc.

  6. Effects of chronic exposure to tributyltin on tissue-specific cytochrome P450 1 regulation in juvenile common carp.

    Science.gov (United States)

    Li, Zhi-Hua; Zhong, Li-Qiao; Mu, Wei-Na; Wu, Yan-Hua

    2016-01-01

    1. The purpose of this study was to compare tributyltin (TBT)-induced cytochrome P450 1 (CYP450 1) regulation in liver, gills and muscle of juvenile common carp (Cyprinus carpio). 2. Fish were exposed to sublethal concentrations of TBT (75, 0.75 and 7.5 μg/L) for 60 days. CYP450 1A was measured at the enzyme activity level as 7-ethoxyresorufin-O-deethylase (EROD) activity, as well as the mRNA expression of CYP450 1 family genes (CYP1A, CYP1B, CYP1C1 and CYP1C2) in fish tissues. 3. Based on the results, the liver displayed the highest absolute levels of EROD activity, both under nonexposed and exposed conditions. Additional, EROD activities and CYP1A gene levels showed a good correlation in all three organs. According to the mRNA expression of CYP450 1 family genes, it suggested that CYP1A was to accommodate most EROD activity in fish, but other CYP450 forms also involved in this proceeding. 4. Overall, the study revealed both similarities and differences in the concentration-dependent CYP450 1 responses of the three target organs, which could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity.

  7. Assessment of adsorption behavior of dibutyltin (DBT) to clay-rich sediments in comparison to the highly toxic tributyltin (TBT)

    International Nuclear Information System (INIS)

    Hoch, Marion; Alonso-Azcarate, Jacinto; Lischick, Martin

    2003-01-01

    Adsorption of dibutyltin to marine sediments is influenced by the type of predominating clay material. - The sorption behavior of dibutyltin (DBT) to four types of natural clay-rich sediments as a function of pH and salinity was studied. The strongest affinity of DBT was found to the montmorillonite-rich sediment, which is characterized by the highest specific surface area and cation exchange capacity of the four used sediments. K d values range between 12 and 40 (l/kg) on simulated marine conditions (pH 8, salinity 32%o). A maximum of DBT adsorption was found at a salinity of 0%o and pH 6. Desorption occurred over the entire studied pH range (4-8) when contaminated sediments interact with butyltin-free water. The maximum of desorption coincided with the minimum of adsorption, and vice versa. The results of DBT adsorption are compared with tributyltin (TBT), and the mechanism of the adsorption process is discussed

  8. Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water

    Energy Technology Data Exchange (ETDEWEB)

    Jin Jing [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Yang Lihua [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Chan, Sidney M.N. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Luan Tiangang, E-mail: cesltg@mail.sysu.edu.cn [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Li Yan [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Tam, Nora F.Y., E-mail: bhntam@cityu.edu.hk [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong)

    2011-01-30

    The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency.

  9. Evaluation of tributyltin toxicity in Chinese rare minnow larvae by abnormal behavior, energy metabolism and endoplasmic reticulum stress.

    Science.gov (United States)

    Li, Zhi-Hua; Li, Ping

    2015-02-05

    Tributyltin (TBT) is a ubiquitous contaminant in aquatic environment, but the detailed mechanisms underlying the toxicity of TBT have not been fully understood. In this study, the effects of TBT on behavior, energy metabolism and endoplasmic reticulum (ER) stress were investigated by using Chinese rare minnow larvae. Fish larvae were exposed at sublethal concentrations of TBT (100, 400 and 800 ng/L) for 7 days. Compared with the control, energy metabolic parameters (RNA/DNA ratio, Na(+)-K(+)-ATPase) were significantly inhibited in fish exposed at highest concentration (800 ng/L), as well as abnormal behaviors observed. Moreover, we found that the PERK (PKR-like ER kinase)-eIF2α (eukaryotic translation initiation factor 2α) pathway, as the main branch was activated by TBT exposure in fish larvae. In short, TBT-induced physiological, biochemical and molecular responses in fish larvae were reflected in parameters measured in this study, which suggest that these biomarkers could be used as potential indicators for monitoring organotin compounds present in aquatic environment. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Towards tributyltin quantification in natural water at the Environmental Quality Standard level required by the Water Framework Directive.

    Science.gov (United States)

    Alasonati, Enrica; Fettig, Ina; Richter, Janine; Philipp, Rosemarie; Milačič, Radmila; Sčančar, Janez; Zuliani, Tea; Tunç, Murat; Bilsel, Mine; Gören, Ahmet Ceyhan; Fisicaro, Paola

    2016-11-01

    The European Union (EU) has included tributyltin (TBT) and its compounds in the list of priority water pollutants. Quality standards demanded by the EU Water Framework Directive (WFD) require determination of TBT at so low concentration level that chemical analysis is still difficult and further research is needed to improve the sensitivity, the accuracy and the precision of existing methodologies. Within the frame of a joint research project "Traceable measurements for monitoring critical pollutants under the European Water Framework Directive" in the European Metrology Research Programme (EMRP), four metrological and designated institutes have developed a primary method to quantify TBT in natural water using liquid-liquid extraction (LLE) and species-specific isotope dilution mass spectrometry (SSIDMS). The procedure has been validated at the Environmental Quality Standard (EQS) level (0.2ngL(-1) as cation) and at the WFD-required limit of quantification (LOQ) (0.06ngL(-1) as cation). The LOQ of the methodology was 0.06ngL(-1) and the average measurement uncertainty at the LOQ was 36%, which agreed with WFD requirements. The analytical difficulties of the method, namely the presence of TBT in blanks and the sources of measurement uncertainties, as well as the interlaboratory comparison results are discussed in detail. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Caspase-10 Is the Key Initiator Caspase Involved in Tributyltin-Mediated Apoptosis in Human Immune Cells

    Directory of Open Access Journals (Sweden)

    Harald F. Krug

    2012-01-01

    Full Text Available Tributyltin (TBT is one of the most toxic compounds produced by man and distributed in the environment. A multitude of toxic activities have been described, for example, immunotoxic, neurotoxic, and endocrine disruptive effects. Moreover, it has been shown for many cell types that they undergo apoptosis after treatment with TBT and the cell death of immune cells could be the molecular background of its immunotoxic effect. As low as 200 nM up to 1 μM of TBT induces all signs of apoptosis in Jurkat T cells within 1 to 24 hrs of treatment. When compared to Fas-ligand control stimulation, the same sequence of events occurs: membrane blebbing, phosphatidylserine externalisation, the activation of the “death-inducing signalling complex,” and the following sequence of cleavage processes. In genetically modified caspase-8-deficient Jurkat cells, the apoptotic effects are only slightly reduced, whereas, in FADD-negative Jurkat cells, the TBT effect is significantly diminished. We could show that caspase-10 is recruited by the TRAIL-R2 receptor and apoptosis is totally prevented when caspase-10 is specifically inhibited in all three cell lines.

  12. Tributyltin and triphenyltin exposure promotes in vitro adipogenic differentiation but alters the adipocyte phenotype in rainbow trout.

    Science.gov (United States)

    Lutfi, Esmail; Riera-Heredia, Natàlia; Córdoba, Marlon; Porte, Cinta; Gutiérrez, Joaquim; Capilla, Encarnación; Navarro, Isabel

    2017-07-01

    Numerous environmental pollutants have been identified as potential obesogenic compounds affecting endocrine signaling and lipid homeostasis. Among them, well-known organotins such as tributyltin (TBT) and triphenyltin (TPT), can be found in significant concentrations in aquatic environments. The aim of the present study was to investigate in vitro the effects of TBT and TPT on the development and lipid metabolism of rainbow trout (Onchorynchus mykiss) primary cultured adipocytes. Results showed that TBT and TPT induced lipid accumulation and slightly enhanced peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer binding protein alpha (C/EBPα) protein expression when compared to a control, both in the presence or absence of lipid mixture. However, the effects were higher when combined with lipid, and in the absence of it, the organotins did not cause complete mature adipocyte morphology. Regarding gene expression analyses, exposure to TBT and TPT caused an increase in fatty acid synthase (fasn) mRNA levels confirming the pro-adipogenic properties of these compounds. In addition, when added together with lipid, TBT and TPT significantly increased cebpa, tumor necrosis factor alpha (tnfa) and ATP-binding cassette transporter 1 (abca1) mRNA levels suggesting a synergistic effect. Overall, our data highlighted that TBT and TPT activate adipocyte differentiation in rainbow trout supporting an obesogenic role for these compounds, although by themselves they are not able to induce complete adipocyte development and maturation suggesting that these adipocytes might not be properly functional. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Enhancement of tributyltin degradation under natural light by N-doped TiO{sub 2} photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Bangkedphol, S., E-mail: sornnarin.bangkedphol@strath.ac.uk [David Livingstone Centre for Sustainability, Department of Civil Engineering, University of Strathclyde, Glasgow, Scotland G1 1XN (United Kingdom); Keenan, H.E. [David Livingstone Centre for Sustainability, Department of Civil Engineering, University of Strathclyde, Glasgow, Scotland G1 1XN (United Kingdom); Davidson, C.M. [WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, Scotland G1 1XL (United Kingdom); Sakultantimetha, A. [David Livingstone Centre for Sustainability, Department of Civil Engineering, University of Strathclyde, Glasgow, Scotland G1 1XN (United Kingdom); Sirisaksoontorn, W.; Songsasen, A. [Department of Chemistry and Centre for Innovation in chemistry, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand)

    2010-12-15

    Photo-degradation of tributyltin (TBT) has been enhanced by TiO{sub 2} nanoparticles doped with nitrogen (N-doped TiO{sub 2}). The N-doped catalyst was prepared by a sol-gel reaction of titanium (IV) tetraisopropoxide with 25% ammonia solution and calcined at various temperatures from 300 to 600 deg. C. X-ray diffraction results showed that N-doped TiO{sub 2} remained amorphous at 300 deg. C. At 400 deg. C the anatase phase occurred then transformed to the rutile phase at 600 deg. C. The crystallite size calculated from Scherrer's equation was in the range of 16-51 nm which depended on the calcination temperature. N-doped TiO{sub 2} calcined at 400 deg. C which contained 0.054% nitrogen, demonstrated the highest photocatalytic degradation of TBT at 28% in 3 h under natural light when compared with undoped TiO{sub 2} and commercial photocatalyst, P25-TiO{sub 2} which gave 14.8 and 18% conversion, respectively.

  14. Pharmacological evaluation of the mechanisms involved in increased adiposity in zebrafish triggered by the environmental contaminant tributyltin.

    Science.gov (United States)

    Ouadah-Boussouf, Nafia; Babin, Patrick J

    2016-03-01

    One proposed contributing factor to the rise in overweight and obesity is exposure to endocrine disrupting chemicals. Tributyltin chloride (TBT), an organotin, induces adipogenesis in cell culture models and may increases adipose mass in vivo in vertebrate model organisms. It has been hypothesized that TBT acts via the peroxisome proliferator activated receptor (PPAR)γ-dependent pathway. However, the mechanisms involved in the effects of TBT exposure on in vivo adipose tissue metabolism remain unexplored. Semitransparent zebrafish larvae, with their well-developed white adipose tissue, offer a unique opportunity for studying the effects of toxicant chemicals and pharmaceuticals on adipocyte biology and whole-organism adiposity in a vertebrate model. Within hours, zebrafish larvae, treated at environmentally-relevant nanomolar concentrations of TBT, exhibited a remarkable increase in adiposity linked to adipocyte hypertrophy. Under the experimental conditions used, we also demonstrated that zebrafish larvae adipose tissue proved to be highly responsive to selected human nuclear receptor agonists and antagonists. Retinoid X receptor (RXR) homodimers and RXR/liver X receptor heterodimers were suggested to be in vivo effectors of the obesogenic effect of TBT on zebrafish white adipose tissue. RXR/PPARγ heterodimers may be recruited to modulate adiposity in zebrafish but were not a necessary requirement for the short term in vivo TBT obesogenic effect. Together, the present results suggest that TBT may induce the promotion of triacylglycerol storage in adipocytes via RXR-dependent pathways without necessary using PPAR isoforms. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Tributyltin bioaccumulation and toxic effects in freshwater gastropods Pomacea canaliculata after a chronic exposure: field and laboratory studies.

    Science.gov (United States)

    Martínez, María L; Piol, María N; Sbarbati Nudelman, Norma; Verrengia Guerrero, Noemí R

    2017-07-01

    Freshwater samples and gastropod mollusks (Pomacea canaliculata) were collected at 5 sampling stations located along the lower Río de la Plata basin, Argentina, to assess the extent of tributyltin (TBT) contamination. Determined data revealed the presence of TBT and some of its breakdown products (dibutyltin: DBT, and monobutyltin: MBT) in all freshwater samples and also in soft tissues of P. canaliculata gastropods. Chronic bioassays (6 months) were performed using female gastropods that had been reared under laboratory conditions and exposed to a similar TBT concentration than the value determined in freshwater samples (1 µg L -1 ). The aims of this study were to evaluate the extent of TBT accumulation, the tissue distribution, and the effects on selected biomarkers (activity of superoxide dismutasa: SOD, activity of catalase: CAT, levels of total glutathione: t-GSH, lipid peroxidation, and activity of acetylcholinesterase: AChE). Gonads presented the highest accumulation, followed by the cephalopedal region, albumin gland, and finally hepatopancreas. Both metabolites, DBT and MBT, were also found. All exposed female animals presented development of a penis reflecting the potential of TBT as an endocrine disrupting chemical for this gastropod species. Results on the selected biomarkers confirmed additional adverse effects induced by TBT. An increase in CAT activity and changes in t-GSH levels are indicative of alterations on the cellular redox status. The inhibition of AChE could reflect signs of neurotoxicity. Altogether, these results reveal a negative impact on the health of this gastropod population.

  16. Action of tributyltin (TBT) on the lipid content and potassium retention in the organotins degradating fungus Cunninghamella elegans.

    Science.gov (United States)

    Bernat, Przemysław; Słaba, Mirosława; Długoński, Jerzy

    2009-09-01

    The purpose of the presented paper was to study the effect of high concentrations of tributyltin (TBT) on the potassium retention and fatty acid (FA) composition of the fungus Cunninghamella elegans recognized as a very efficient TBT degrader. An increase in TBT had a strong influence on the potassium concentration in the fungus. In growth medium without TBT, the potassium content of the fungal cells was 5.8 mg K(+) g dry weight(-1). The maximum concentration of K(+) was 15.06 mg g(-1) dry weight at 30 mg l(-1) of TBT. The major FAs that characterized the tested strain were C16:0, C18:1, C18:2, C18:3 and C18:0. TBT in the concentration range 5-30 mg l(-1) strongly influenced the FA composition. In the presence of the organotin, the degree of saturation increased. It suggests that the observed changes promote an increase in the lipid ordering of the membrane by reducing its permeability and inhibiting potassium ion efflux.

  17. In vitro approaches to evaluate toxicity induced by organotin compounds tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) in neuroblastoma cells.

    Science.gov (United States)

    Ferreira, Martiña; Blanco, Lucía; Garrido, Alejandro; Vieites, Juan M; Cabado, Ana G

    2013-05-01

    The toxic effects of the organotin compounds (OTCs) monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) were evaluated in vitro in a neuroblastoma human cell line. Mechanisms of cell death, apoptosis versus necrosis, were studied by using several markers: inhibition of cell viability and proliferation, F-actin, and mitochondrial membrane potential changes as well as reactive oxygen species (ROS) production and DNA fragmentation. The most toxic effects were detected with DBT and TBT even at very low concentrations (0.1-1 μM). In contrast, MBT induced lighter cytotoxic changes at the higher doses tested. None of the studied compounds stimulated propidium iodide uptake, although the most toxic chemical, TBT, caused lactate dehydrogenase release at the higher concentrations tested. These findings suggest that in neuroblastoma, OTC-induced cytotoxicity involves different pathways depending on the compound, concentration, and incubation time. A screening method for DBT and TBT quantification based on cell viability loss was developed, allowing a fast detection alternative to complex methodology.

  18. Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water.

    Science.gov (United States)

    Jin, Jing; Yang, Lihua; Chan, Sidney M N; Luan, Tiangang; Li, Yan; Tam, Nora F Y

    2011-01-30

    The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. DNA damage and transcriptional changes induced by tributyltin (TBT) after short in vivo exposures of Chironomus riparius (Diptera) larvae.

    Science.gov (United States)

    Morales, Mónica; Martínez-Paz, Pedro; Ozáez, Irene; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2013-08-01

    Tributyltin (TBT) is a widespread environmental contaminant in aquatic systems whose adverse effects in development and reproduction are related to its well-known endocrine-disrupting activity. In this work, the early molecular effects of TBT in Chironomus riparius (Diptera) were evaluated by analyzing its DNA damaging potential and the transcriptional response of different endocrine-related genes. Twenty-four-hour in vivo exposures of the aquatic larvae, at environmentally relevant doses of TBT, revealed genotoxic activity as shown by significant increases in DNA strand breaks quantified with the comet assay. TBT was also able to induce significant increases in transcripts from the ecdysone receptor gene (EcR), the ultraspiracle gene (usp) (insect ortholog of the retinoid X receptor), the estrogen-related receptor (ERR) gene and the E74 early ecdysone-inducible gene, as measured by real-time RT-PCR. In contrast, the expression of the vitellogenin (vg) gene remained unaltered, while the hsp70 gene appeared to be down-regulated. The ability of TBT to up-regulate hormonal target genes provides the first evidence, at genomic level, of its endocrine disruptive effects and also suggests a mechanism of action that mimics ecdysteroid hormones in insects. These data reveal for the first time the early genomic effects of TBT on an insect genome. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Imposex and novel mechanisms of reproductive failure induced by tributyltin (TBT) in the freshwater snail Pomacea canaliculata.

    Science.gov (United States)

    Giraud-Billoud, Maximiliano; Vega, Israel A; Wuilloud, Rodolfo G; Clément, María E; Castro-Vazquez, Alfredo

    2013-10-01

    The effects of tributyltin (TBT) on mortality and reproduction were studied in the invasive snail Pomacea canaliculata. The nominal median lethal concentration (LC50) was 9 µg TBT/L, after 28 d. The nominal no-observed effect on lethality concentration (NOECL) was 6 µg TBT/L after the same period. Male-female couples and females that had been group-mated but were isolated from males during the experiment (isolated females) were exposed (for 28 d) to either 0 µg/L or 6 µg/L of TBT (nominal NOECL-exposed). Copulation and oviposition frequencies, egg clutch mass, and percentage of egg fertility were recorded. Gonads (both sexes) and the seminal receptacle (females) were studied histologically at the end of the experiment. A significant decrease in copulation frequency was observed in mated-exposed females. Exposure also decreased oviposition frequency of mated-exposed and isolated-exposed females, but only the latter reached significance. No differences in either egg clutch mass or percentage of fertility were observed at first oviposition, but both parameters were drastically reduced in subsequent egg clutches of exposed females. No histological alterations were observed in gonads of TBT-exposed animals; however, sperm storage in the seminal receptacle was drastically decreased in exposed females. Imposex but no oviductal obstruction was observed in all exposed females. It is concluded that TBT induces reproductive failure in P. canaliculata by decreasing copulation frequency and by severely affecting sperm storage by the female. © 2013 SETAC.

  1. Aeromonas molluscorum Av27 is a potential tributyltin (TBT) bioremediator: phenotypic and genotypic characterization indicates its safe application.

    Science.gov (United States)

    Cruz, Andreia; Areias, Dário; Duarte, Ana; Correia, António; Suzuki, Satoru; Mendo, Sónia

    2013-09-01

    Aeromonas molluscorum Av27 is an estuarine bacterium highly resistant to tributyltin (TBT). Also, the strain is able to degrade TBT into the less toxic compounds dibutyltin and monobutyltin. Therefore, this bacterium has potential to be employed in bioremediation processes. In this context, defining its biological safety is crucial. With that purpose a number of intrinsic characteristics, usually present/associated with virulent strains, were investigated. Few virulence factors were detected in strain Av27. For instance, a DNase gene is present, but it is not apparently expressed in vitro. Motility, adherence factor and phospholipase activity were also detected. Additionally, cytotoxicity to Vero cells was negative. Resistance to penicillin (10 μg ml(-1)), amoxicillin/clavulanic acid (30 μg ml(-1)) and cephalothin (30 μg ml(-1)) and also to the vibriostatic agent O/129 was observed. Five plasmids (4, 7, 10, 100 kb and one greater than 100 kb) were identified. No Class I and II integrons were detected. Study of the optimal growth conditions showed that Av27 easily adapts to different environmental conditions. Overall, the results suggest that A. molluscorum Av27 can be considered safe to use to bioremediate TBT in contaminated environments.

  2. Tributyltin induces G2/M cell cycle arrest via NAD(+)-dependent isocitrate dehydrogenase in human embryonic carcinoma cells.

    Science.gov (United States)

    Asanagi, Miki; Yamada, Shigeru; Hirata, Naoya; Itagaki, Hiroshi; Kotake, Yaichiro; Sekino, Yuko; Kanda, Yasunari

    2016-04-01

    Organotin compounds, such as tributyltin (TBT), are well-known endocrine-disrupting chemicals (EDCs). We have recently reported that TBT induces growth arrest in the human embryonic carcinoma cell line NT2/D1 at nanomolar levels by inhibiting NAD(+)-dependent isocitrate dehydrogenase (NAD-IDH), which catalyzes the irreversible conversion of isocitrate to α-ketoglutarate. However, the molecular mechanisms by which NAD-IDH mediates TBT toxicity remain unclear. In the present study, we examined whether TBT at nanomolar levels affects cell cycle progression in NT2/D1 cells. Propidium iodide staining revealed that TBT reduced the ratio of cells in the G1 phase and increased the ratio of cells in the G2/M phase. TBT also reduced cell division cycle 25C (cdc25C) and cyclin B1, which are key regulators of G2/M progression. Furthermore, apigenin, an inhibitor of NAD-IDH, mimicked the effects of TBT. The G2/M arrest induced by TBT was abolished by NAD-IDHα knockdown. Treatment with a cell-permeable α-ketoglutarate analogue recovered the effect of TBT, suggesting the involvement of NAD-IDH. Taken together, our data suggest that TBT at nanomolar levels induced G2/M cell cycle arrest via NAD-IDH in NT2/D1 cells. Thus, cell cycle analysis in embryonic cells could be used to assess cytotoxicity associated with nanomolar level exposure of EDCs.

  3. AMP-activated protein kinase-mediated glucose transport as a novel target of tributyltin in human embryonic carcinoma cells.

    Science.gov (United States)

    Yamada, Shigeru; Kotake, Yaichiro; Sekino, Yuko; Kanda, Yasunari

    2013-05-01

    Organotin compounds such as tributyltin (TBT) are known to cause various forms of cytotoxicity, including developmental toxicity and neurotoxicity. However, the molecular target of the toxicity induced by nanomolar levels of TBT has not been identified. In the present study, we found that exposure to 100 nM TBT induced growth arrest in human pluripotent embryonic carcinoma cell line NT2/D1. Since glucose provides metabolic energy, we focused on the glycolytic system. We found that exposure to TBT reduced the levels of both glucose-6-phosphate and fructose-6-phosphate. To investigate the effect of TBT exposure on glycolysis, we examined glucose transporter (GLUT) activity. TBT exposure inhibited glucose uptake via a decrease in the level of cell surface-bound GLUT1. Furthermore, we examined the effect of AMP-activated protein kinase (AMPK), which is known to regulate glucose transport by facilitating GLUT translocation. Treatment with the potent AMPK activator, AICAR, restored the TBT-induced reduction in cell surface-bound GLUT1 and glucose uptake. In conclusion, these results suggest that exposure to nanomolar levels of TBT causes growth arrest by targeting glycolytic systems in human embryonic carcinoma cells. Thus, understanding the energy metabolism may provide new insights into the mechanisms of metal-induced cytotoxicity.

  4. Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water

    International Nuclear Information System (INIS)

    Jin Jing; Yang Lihua; Chan, Sidney M.N.; Luan Tiangang; Li Yan; Tam, Nora F.Y.

    2011-01-01

    The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency.

  5. Bis(tributyltin)oxide (TBTO) decreases the food allergic response against peanut and ovalbumin in Brown Norway rats

    International Nuclear Information System (INIS)

    Jonge, Jonathan D. de; Ezendam, Janine; Knippels, Leon M.J.; Odink, Jennie; Pourier, Milanthy S.; Penninks, Andre H.; Pieters, Raymond; Loveren, Henk van

    2007-01-01

    Other factors than the allergen itself may be of importance in the development of food allergy. This report describes the influence of the immunosuppressive compound bis(tributyltin)oxide (TBTO), present in the food chain, on the development of food allergy to peanut or ovalbumin in Brown Norway (BN) rats. To study these effects BN rats were sensitized to either 1 or 10 mg peanut or ovalbumin by daily oral gavage and the TBTO-groups were fed a diet containing 80 mg TBTO per kg diet. Co-exposure to TBTO not only resulted in decreased general immunologic parameters such as weights of mesenteric lymph nodes and Peyer's patches, lymphocyte proliferation rates in splenocytes, but also on allergic parameters. In the peanut allergen-model TBTO decreased allergen-specific Th2 cytokine production by spleen cells, number of eosinophilic and basophilic granulocytes in the blood and production of mast cell protease II after oral food challenge. In the ovalbumin allergen-model TBTO decreased the number of eosinophilic and basophilic granulocytes, allergen-specific IgE and production of mast cell protease II after oral food challenge. The data imply that in the process of risk assessment of food allergy attention should be given to immunomodulating compounds present in the diet

  6. Statistics of Extremes

    KAUST Repository

    Davison, Anthony C.; Huser, Raphaë l

    2015-01-01

    Statistics of extremes concerns inference for rare events. Often the events have never yet been observed, and their probabilities must therefore be estimated by extrapolation of tail models fitted to available data. Because data concerning the event

  7. Analysis of extreme events

    CSIR Research Space (South Africa)

    Khuluse, S

    2009-04-01

    Full Text Available ) determination of the distribution of the damage and (iii) preparation of products that enable prediction of future risk events. The methodology provided by extreme value theory can also be a powerful tool in risk analysis...

  8. Acute lower extremity ischaemia

    African Journals Online (AJOL)

    Acute lower extremity ischaemia. Acute lower limb ischaemia is a surgical emergency. ... is ~1.5 cases per 10 000 persons per year. Acute ischaemia ... Table 2. Clinical features discriminating embolic from thrombotic ALEXI. Clinical features.

  9. Mercury and Methylmercury Concentrations in Muscle Tissue of Fish Caught in Major Rivers of the Czech Republic

    Directory of Open Access Journals (Sweden)

    K. Kružíková

    2008-01-01

    Full Text Available The aim of the study was to evaluate mercury contamination at twelve outlet sites of rivers in the Czech Republic (Labe, Ohře, Vltava, Berounka, Sázava, Otava, Lužnice, Svratka, Dyje, Morava and Odra. As an indicator, we used muscle tissue of the chub (Leuciscus cephalus caught at selected sites in 2007. A total of 96 fish were examined. Total mercury was determined by atomic absorption spectrophotometry using the AMA 254 analyzer and methylmercury was determined by gas chromatography with electron-capture detection. Total mercury (THg and methylmercury (MeHg concentrations ranged 0.039–0.384 mg kg-1 fresh weight and 0.033–0.362 mg kg-1 fresh weight, respectively. Mercury bound in methylmercury (HgMe made up on average about 82.2% of total mercury. The highest mercury concentrations were found in fish from Obříství, a site on Labe (THg 0.263 ± 0.086 mg kg-1; MeHg 0.256 ± 0.084 mg kg-1. Mercury concentrations in fish from rivers that cross the borders of the Czech Republic (Labe, Odra and Morava were low. The Czech Republic therefore does not contribute significantly to river pollution outside its national borders. Hazard indices of the sites monitored were well below 1, and reached 1.365 only in Obříství on Labe for fisherman’s family members (i.e. in the case of annual consumption of 10 kg fish. This indicates possible hazards involved in eating meat of fish caught in that location. Based on PTWI for methylmercury, the maximum amount of fish meat allowed for consumption per week was calculated. The site with the lowest value was Obříství on Labe (0.44 kg. The results of this study present a partial contribution to health risk assessment on the major rivers in Czech Republic.

  10. A longitudinal analysis of prenatal exposure to methylmercury and fatty acids in the Seychelles.

    Science.gov (United States)

    Stokes-Riner, Abbie; Thurston, Sally W; Myers, Gary J; Duffy, Emeir M; Wallace, Julie; Bonham, Maxine; Robson, Paula; Shamlaye, Conrad F; Strain, J J; Watson, Gene; Davidson, Philip W

    2011-01-01

    Maternal fish consumption during pregnancy exposes the fetus simultaneously to methylmercury (MeHg) and long chain polyunsaturated fatty acids (LCPUFA). Data from the Seychelles Child Development Nutrition Study (SCDNS) showed a negative association of MeHg with child development when children were 30 months of age, only when controlling for LCPUFA. Concomitantly, n-3 LCPUFA were found to have a significant positive association only at 9 months. These findings suggest that the effects of MeHg and LCPUFA may vary with age over the first few years of life. We address this by including outcomes at two ages and adjusting for the child's age at testing. A longitudinal analysis utilizing linear mixed models was performed to assess the associations of maternal hair total mercury (THg, a biomarker for MeHg) and maternal LCPUFA with children's Bayley Scales of Infant Development Psychomotor Developmental Index (BSID-II PDI) at 9 and 30 months of age, and to determine whether these associations change over time. Data from 228 children were included. Maternal hair MeHg had a negative effect on BSID PDI, while maternal n-3 LCPUFA had a positive effect. These effects did not change significantly from 9 to 30 months in this analysis. The longitudinal analysis provides increased power for estimating the relationships of prenatal MeHg and LCPUFA exposures during child development. Significant associations of these exposures in opposite directions confirm the importance of LCPUFA in development and the need to adjust for maternal nutrition when studying prenatal MeHg exposure. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Mercury cycling in stream ecosystems. 3. Trophic dynamics and methylmercury bioaccumulation

    Science.gov (United States)

    Chasar, L.C.; Scudder, B.C.; Stewart, A.R.; Bell, A.H.; Aiken, G.R.

    2009-01-01

    Trophic dynamics (community composition and feeding relationships) have been identified as important drivers of methylmercury (MeHg) bioaccumulation in lakes, reservoirs, and marine ecosystems. The relative importance of trophic dynamics and geochemical controls on MeHg bioaccumulation in streams, however, remains poorly characterized. MeHg bioaccumulation was evaluated in eight stream ecosystems across the United States (Oregon, Wisconsin, and Florida) spanning large ranges in climate, landscape characteristics, atmospheric Hg deposition, and stream chemistry. Across all geographic regions and all streams, concentrations of total Hg (THg) in top predator fish and forage fish, and MeHg in invertebrates, were strongly positively correlated to concentrations of filtered THg (FTHg), filtered MeHg (FMeHg), and dissolved organic carbon (DOC); to DOC complexity (as measured by specific ultraviolet absorbance); and to percent wetland in the stream basins. Correlations were strongest for nonurban streams. Although regressions of log[Hg] versus ??15N indicate that Hg in biota increased significantly with increasing trophic position within seven of eight individual streams, Hg concentrations in top predator fish (including cutthroat, rainbow, and brown trout; green sunfish; and largemouth bass) were not strongly influenced by differences in relative trophic position. Slopes of log[Hg] versus ??15N, an indicator of the efficiency of trophic enrichment, ranged from 0.14 to 0.27 for all streams. These data suggest that, across the large ranges in FTHg (0.14-14.2 ng L-1), FMeHg (0.023-1.03 ng L-1), and DOC (0.50-61.0 mg L-1) found in this study, Hg contamination in top predator fish in streams likely is dominated by the amount of MeHg available for uptake at the base of the food web rather than by differences in the trophic position of top predator fish. ?? 2009 American Chemical Society.

  12. Benthic and pelagic pathways of methylmercury bioaccumulation in estuarine food webs of the northeast United States.

    Directory of Open Access Journals (Sweden)

    Celia Y Chen

    Full Text Available Methylmercury (MeHg is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine. MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides. Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column.

  13. Robust microwave-assisted extraction protocol for determination of total mercury and methylmercury in fish tissues

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, L. Hinojosa; Rahman, G.M. Mizanur [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); Kingston, H.M. Skip [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States)], E-mail: kingston@duq.edu

    2009-01-12

    A rapid and efficient closed vessel microwave-assisted extraction (MAE) method based on acidic leaching was developed and optimized for the extraction of total mercury (Hg), inorganic mercury (Hg{sup 2+}) and methylmercury (CH{sub 3}Hg{sup +}) from fish tissues. The quantitative extraction of total Hg and mercury species from biological samples was achieved by using 5 mol L{sup -1} HCl and 0.25 mol L{sup -1} NaCl during 10 min at 60 deg. C. Total Hg content was determined using inductively coupled plasma mass spectrometry (ICP-MS). Mercury species were measured by liquid chromatography hyphenated with inductively coupled plasma mass spectrometry (LC-ICP-MS). The method was validated using biological certified reference materials ERM-CE464, DOLT-3, and NIST SRM-1946. The analytical results were in good agreement with the certified reference values of total Hg and CH{sub 3}Hg{sup +} at a 95% confidence level. Further, accuracy validation using speciated isotope-dilution mass spectrometry (SIDMS, as described in the EPA Method 6800) was carried out. SIDMS was also applied to study and correct for unwanted species transformation reactions during and/or after sample preparation steps. For the studied reference materials, no statistically significant transformation between mercury species was observed during the extraction and determination procedures. The proposed method was successfully applied to fish tissues with good agreement between SIDMS results and external calibration (EC) results. Interspecies transformations in fish tissues were slightly higher than certified reference materials due to differences in matrix composition. Depending on the type of fish tissue, up to 10.24% of Hg{sup 2+} was methylated and up to 1.75% of CH{sub 3}Hg{sup +} was demethylated to Hg{sup 2+}.

  14. Neurobehavioral toxicity in progeny of rat mothers exposed to methylmercury during gestation

    Directory of Open Access Journals (Sweden)

    Dinesh N. Gandhi

    2014-03-01

    Full Text Available INTRODUCTION: Methylmercury (MeHg is recognized as one of the most hazardous environmental pollutants. This may be a concern to long-term consumption of contaminated fish and seafood for health risk to pregnant women and their children. AIM: An animal study was conducted to assess the effect of MeHg exposure on rodent offspring following in utero exposure. METHODS: Pregnant Wister rats were treated by gavage with MeHg at dose levels of 0.5, 1.0 and 2.0 mg/kg/day from gestation day (GD 5 till parturition, and then were allowed to deliver. RESULTS: Dams treated with 2.0 mg/kg/day MeHg group showed signs of toxicity such as gait alterations and hyperactivity resulting in the failure to deliver sustainable viable pups. MeHg had significant effects on body weight gain of dams during GD 5 till parturition. MeHg had no significant effects on the ages of physical developments such as pinna detachment, incisor eruptions or eye opening as well as alter cliff avoidance, surface righting, swimming ontogeny, startle reflex, pivoting, negative geotaxis, or forelimb and hindlimb grip strength in either sex. Exposure to 1.0 mg/kg/day MeHg treatment group prolonged gestation period, retard mid-air righting in male pups, shortened forelimb grip strength measured on rotating rod in either sex and enhanced open field behaviour in male pups. Data obtained from Functional Observation Battery (FOB also revealed impairment of neuromotor performance in male pups. The male pups appeared to be more susceptible than the female pups. CONCLUSION. Overall, the dose level of MeHg in the present study produced a few adverse effects on the neurobehavioral parameters, and it may alter neuromotor performance of the male pups.

  15. Sources of water column methylmercury across multiple estuaries in the Northeast U.S.

    Science.gov (United States)

    Balcom, Prentiss H; Schartup, Amina T; Mason, Robert P; Chen, Celia Y

    2015-12-20

    Estuarine water column methylmercury (MeHg) is an important driver of mercury (Hg) bioaccumulation in pelagic organisms and thus it is necessary to understand the sources and processes affecting environmental levels of MeHg. Increases in water column MeHg concentrations can ultimately be transferred to fish consumed by humans, but despite this, the sources of MeHg to the estuarine water column are still poorly understood. Here we evaluate MeHg sources across 4 estuaries and 10 sampling sites and examine the distributions and partitioning of sediment and water column MeHg across a geographic range (Maine to New Jersey). Our study sites present a gradient in the concentrations of sediment, pore water and water column Hg species. Suspended particle MeHg ranged from below detection to 187 pmol g -1 , dissolved MeHg from 0.01 to 0.68 pM, and sediment MeHg from 0.01 to 109 pmol g -1 . Across multiple estuaries, dissolved MeHg correlated with Hg species in the water column, and sediment MeHg correlated with sediment total Hg (HgT). Water column MeHg did not correlate well with sediment Hg across estuaries, indicating that sediment concentrations were not a good predictor of water MeHg concentrations. This is an unexpected finding since it has been shown that MeHg production from inorganic Hg 2+ within sediment is the primary source of MeHg to coastal waters. Additional sources of MeHg regulate water column MeHg levels in some of the shallow estuaries included in this study.

  16. Subchronic effects of methylmercury on plasma and organ biochemistries in great egret nestlings

    Science.gov (United States)

    Hoffman, D.J.; Spalding, M.G.; Frederick, P.C.

    2005-01-01

    In recent years, high concentrations of mercury have been found in wading birds in Florida, USA. Great egret (Ardea alba) chicks (2 weeks old) were dosed orally daily with the equivalent of 0, 0.5, or 5 ug/g Hg as methylmercury chloride in the diet for up to 12 weeks. Weakness of the legs or paralysis occurred in all high-dosed birds. Geometric mean blood Hg concentrations were 0.17, 10.3, and 78.5 ug/g (wet wt), respectively. Mercury concentrations for organs (ug/g wet wt), including brain (0.22, 3.4, and 35, respectively), liver (0.34, 15.1, 138, respectively), and kidney (0.28, 8.1, and 120, respectively), increased in a dose-dependent manner. Total glutathione (GSH) peroxidase activity was significantly lower in the plasma, brain, liver, and kidney of the high-dosed group. Plasma aspartate aminotransferase activity increased with mercury treatment, whereas lactate dehydrogenase activity decreased. Four other plasma chemistries were decreased significantly in the high-dosed group and included uric acid, total protein, albumin, and inorganic phosphorus. Lipid peroxidation increased in liver (low and high dose) and brain (high dose). Tissue changes in concentrations of reduced thiols included decreased total thiols and protein-bound thiols in liver, decreased protein-bound thiols in kidney, and increased GSH in kidney and brain. Activities of GSH S-transferase and oxidized glutathione reductase increased in liver. In kidney, GSH S-transferase and glucose-6-phosphate dehydrogenase activities increased with mercury dose. These findings, including apparent compensatory changes, are compared to other Hg studies where oxidative stress was reported in egrets, herons, and diving ducks in the field and mallards in the laboratory.

  17. Toxicity reference values for methylmercury effects on avian reproduction: Critical review and analysis.

    Science.gov (United States)

    Fuchsman, Phyllis C; Brown, Lauren E; Henning, Miranda H; Bock, Michael J; Magar, Victor S

    2017-02-01

    Effects of mercury (Hg) on birds have been studied extensively and with increasing frequency in recent years. The authors conducted a comprehensive review of methylmercury (MeHg) effects on bird reproduction, evaluating laboratory and field studies in which observed effects could be attributed primarily to Hg. The review focuses on exposures via diet and maternal transfer in which observed effects (or lack thereof) were reported relative to Hg concentrations in diet, eggs, or adult blood. Applicable data were identified for 23 species. From this data set, the authors identified ranges of toxicity reference values suitable for risk-assessment applications. Typical ranges of Hg effect thresholds are approximately 0.2 mg/kg to >1.4 mg/kg in diet, 0.05 mg/kg/d to 0.5 mg/kg/d on a dose basis, 0.6 mg/kg to 2.7 mg/kg in eggs, and 2.1 mg/kg to >6.7 mg/kg in parental blood (all concentrations on a wet wt basis). For Hg in avian blood, the review represents the first broad compilation of relevant toxicity data. For dietary exposures, the current data support TRVs that are greater than older, commonly used TRVs. The older diet-based TRVs incorporate conservative assumptions and uncertainty factors that are no longer justified, although they generally were appropriate when originally derived, because of past data limitations. The egg-based TRVs identified from the review are more similar to other previously derived TRVs but have been updated to incorporate new information from recent studies. While important research needs remain, a key recommendation is that species not yet tested for MeHg toxicity should be evaluated using toxicity data from tested species with similar body weights. Environ Toxicol Chem 2017;36:294-319. © 2016 SETAC. © 2016 SETAC.

  18. Toxic effects of dietary methylmercury on immune function and hematology in American kestrels (Falco sparverius)

    Science.gov (United States)

    Fallacara, Dawn M.; Halbrook, Richard S.; French, John B.

    2011-01-01

    Fifty-nine adult male American kestrels (Falco sparverius) were assigned to one of three diet formulations including 0 (control), 0.6, and 3.9 μg/g (dry wt) methylmercury (MeHg). Kestrels received their diets daily for 13 weeks to assess the effects of dietary MeHg on immunocompetence. Immunotoxic endpoints included assessment of cell-mediated immunity (CMI) using the phytohemagglutinin (PHA) skin-swelling assay and primary and secondary antibody-mediated immune responses (IR) via the sheep red blood cell (SRBC) hemagglutination assay. Select hematology and histology parameters were evaluated to corroborate the results of functional assays and to assess immunosuppression of T and B cell-dependent components in spleen tissue. Kestrels in the 0.6 and 3.9 μg/g MeHg groups exhibited suppression of CMI, including lower PHA stimulation indexes (p = 0.019) and a 42 to 45% depletion of T cell-dependent splenic lymphoid tissue (p = 0.006). Kestrels in the 0.6 μg/g group exhibited suppression of the primary IR to SRBCs (p = 0.014). MeHg did not have a noticeable effect on the secondary IR (p = 0.166). Elevation of absolute heterophil counts (p p p = 0.003) was apparent in the 3.9 μg/g group at week 12. Heterophilia, or the excess of heterophils in peripheral blood above normal ranges, was apparent in seven of 17 (41%) kestrels in the 3.9 μg/g group and was indicative of an acute inflammatory response or physiological stress. This study revealed that adult kestrels were more sensitive to immunotoxic effects of MeHg at environmentally relevant dietary concentrations than they were to reproductive effects as previously reported.

  19. Methylmercury transport across the blood-brain barrier by molecular mimicry

    International Nuclear Information System (INIS)

    Kerper, L.E.; Ballatori, N.; Clarkson, T.W.

    1990-01-01

    The mechanism by which methylmercury (MeHg) crosses the blood-brain barrier is not known. Co-administration of MeHg with L-cysteine by intravenous injection has been shown to accelerate MeHg uptake into brain tissue in rats. Since the complex of MeHg with L-cysteine is structurally similar to L-methionine, a substrate for the L (leucine-preferring) neutral amino acid transport system, this amino acid carrier may be involved in MeHg uptake into brain. To examine this hypothesis, the rapid carotid infusion technique was used in the rat. The concentration-dependence of initial rates of Me 203 Hg uptake into rat brains following injection of Me 203 Hg-L-cysteine complex was non-linear, exhibiting characteristics of saturable transport (K m 250 μM, V max 700 pmol·g -1 ·15 s -1 ). A slower, nonsaturable uptake was seen following MeHg-D-cysteine injection. MeHg-L-cysteine uptake was inhibited by co-injection of L-methionine (K i 200 μM), D-methionine (K i 600 μM), and amino acid analog 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (K i 1.4 mM), but not by amino acid analog α-methylaminoisobutyric acid. Transport of 14 C-L-phenylalanine was inhibited by MeHg-L-cysteine, but not by MeHgCl. The results suggest that MeHg may enter brain capillary endothelial cells as a cysteine complex, via amino acid transport system L

  20. Subcellular Targeting of Methylmercury Lyase Enhances Its Specific Activity for Organic Mercury Detoxification in Plants1

    Science.gov (United States)

    Bizily, Scott P.; Kim, Tehryung; Kandasamy, Muthugapatti K.; Meagher, Richard B.

    2003-01-01

    Methylmercury is an environmental pollutant that biomagnifies in the aquatic food chain with severe consequences for humans and other animals. In an effort to remove this toxin in situ, we have been engineering plants that express the bacterial mercury resistance enzymes organomercurial lyase MerB and mercuric ion reductase MerA. In vivo kinetics experiments suggest that the diffusion of hydrophobic organic mercury to MerB limits the rate of the coupled reaction with MerA (Bizily et al., 2000). To optimize reaction kinetics for organic mercury compounds, the merB gene was engineered to target MerB for accumulation in the endoplasmic reticulum and for secretion to the cell wall. Plants expressing the targeted MerB proteins and cytoplasmic MerA are highly resistant to organic mercury and degrade organic mercury at 10 to 70 times higher specific activity than plants with the cytoplasmically distributed wild-type MerB enzyme. MerB protein in endoplasmic reticulum-targeted plants appears to accumulate in large vesicular structures that can be visualized in immunolabeled plant cells. These results suggest that the toxic effects of organic mercury are focused in microenvironments of the secretory pathway, that these hydrophobic compartments provide more favorable reaction conditions for MerB activity, and that moderate increases in targeted MerB expression will lead to significant gains in detoxification. In summary, to maximize phytoremediation efficiency of hydrophobic pollutants in plants, it may be beneficial to target enzymes to specific subcellular environments. PMID:12586871

  1. Mercury and methylmercury dynamics in a coastal plain watershed, New Jersey, USA

    Science.gov (United States)

    Barringer, J.L.; Riskin, M.L.; Szabo, Z.; Reilly, P.A.; Rosman, R.; Bonin, J.L.; Fischer, J.M.; Heckathorn, H.A.

    2010-01-01

    The upper Great Egg Harbor River watershed in New Jersey's Coastal Plain is urbanized but extensive freshwater wetlands are present downstream. In 2006-2007, studies to assess levels of total mercury (THg) found concentrations in unfiltered streamwater to range as high as 187 ng/L in urbanized areas. THg concentrations were pH and concentrations of dissolved oxygen and nitrate decreased with flushing of soils after rain. Most of the river's flow comes from groundwater seepage; unfiltered groundwater samples contained up to 177 ng/L of THg in urban areas where there is a history of well water with THg that exceeds the drinking water standard (2,000 ng/L). THg concentrations were lower (<25 ng/L) in unfiltered groundwater from downstream wetland areas. In addition to higher THg concentrations (mostly particulate), concentrations of chloride were higher in streamwater and groundwater from urban areas than in those from downstream wetland areas. Methylmercury (MeHg) concentrations in unfiltered streamwater ranged from 0.17 ng/L at a forest/wetlands site to 2.94 ng/L at an urban site. The percentage of THg present as MeHg increased as the percentage of forest + wetlands increased, but also was high in some urban areas. MeHg was detected only in groundwater <1 m below the water/sediment interface. Atmospheric deposition is presumed to be the main source of Hg to the wetlands and also may be a source to groundwater, where wastewater inputs in urban areas are hypothesized to mobilize Hg deposited to soils. ?? 2010 US Government.

  2. Assessment of human health risk associated with methylmercury in the imported fish marketed in the Caribbean.

    Science.gov (United States)

    Fuentes-Gandara, Fabio; Herrera-Herrera, Claudia; Pinedo-Hernández, José; Marrugo-Negrete, José; Díez, Sergi

    2018-08-01

    The decline in marine and freshwaters catches in recent years in Colombia has led to a change in dietary habits, with an increase in the purchase and consumption of imported fish. This is of particular concern as fish are sometimes caught in mercury-contaminated waters, and are subsequently sold canned or uncanned. In addition, canned tuna has received little attention as it is widely assumed that concentrations are low. In this study, total mercury (THg) and methylmercury (MeHg) concentrations were evaluated in three imported fish species marketed in Colombia, Prochilodus lineatus, Prochilodus reticulatus, and Pangasianodon hypophthalmus, plus four brands of canned tuna and one of sardines. One brand of tuna showed the highest mean concentrations of THg (0.543 ± 0.237 μg/g, wet weight, ww) and MeHg (0.518 ± 0.337 μg/g ww), while concentrations in P. hypophthalmus were approximately 30 times lower (≈0.02 µg/g ww). The estimated weekly intake (EWI) in children was above the provisional tolerable weekly intake (PTWI) of MeHg established by the Joint FAO/World Health Organization (WHO) Expert Committee on Food Additives (JECFA) in 2007, 1.6 μg/kg body weight (bw) per week, for all the canned tuna brands. Values for adults were below PTWI, whereas for women of childbearing age, values were above PTWI only for brand D of canned tuna. The estimate of the potential risk indicated that MeHg levels in canned tuna can generate negative effects in vulnerable groups, while the EWI of fresh fish did not pose a threat to the general population. Therefore, establishing strategies to address the high consumption of canned tuna, and continuous monitoring to control commercial food, are recommended to decrease Hg exposure. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Dietary exposure of Hong Kong secondary school students to total mercury and methylmercury from fish intake.

    Science.gov (United States)

    Tang, Anna Shiu Ping; Kwong, Ka Ping; Chung, Stephen Wai Cheung; Ho, Yuk Yin; Xiao, Ying

    2009-01-01

    Fish is the main source of dietary exposure to methylmercury (MeHg), which is a public health concern owing to its potential neurotoxicity. To evaluate the public health risk, this study estimated the total mercury (tHg) and MeHg exposure from fish intake in Hong Kong secondary school students. Median tHg and MeHg concentrations of 280 samples purchased from different commercial outlets (covering 89 species of whole fish and three types of canned tuna), together with the local food consumption data of secondary school students obtained by semi-quantitative food frequency questionnaire in 2000, were used to estimate dietary exposure from fish intake for the average and high consumer (95th percentile exposure). For tHg, the median concentration was 63 µg kg(-1) (range 3-1370 µg kg(-1)) and estimated exposures ranged 0.5-0.6 µg kg(-1) body weight (bw) week(-1) for an average consumer and 1.6-1.9 µg kg(-1) bw week(-1) for a high consumer. For MeHg, median concentration was 48 µg kg(-1) (range 3-1010 µg kg(-1)) and estimated dietary exposures were 0.4-0.5 µg kg(-1) bw week(-1) for an average consumer and 1.2-1.4 µg kg(-1) bw week(-1) for a high consumer. These values are below the respective provisional tolerable weekly intake (PTWI) established by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA). The health risk is greater for high consumers since MeHg exposures may approach or exceed the PTWI when other dietary sources are taken into account.

  4. Survey of total mercury and methylmercury levels in edible fish from the Adriatic Sea.

    Science.gov (United States)

    Storelli, M M; Giacominelli-Stuffler, R; Storelli, A; D'Addabbo, R; Palermo, C; Marcotrigiano, G O

    2003-12-01

    Total mercury and methylmercury concentrations were measured in the muscle tissue of different fish species from the Adriatic Sea to ascertain whether the concentrations exceeded the maximum level fixed by the European Commission. Large species-dependent variability was observed. The highest total mercury mean concentrations were in benthic (0.20-0.76 microg g(-1) wet wt) and demersal fish (0.22-0.73 microg g(-1) wet wt), while pelagic species showed the lowest levels (0.09-0.23 microg g(-1) wet wt). In 15% of frost fish, in 42% of skate and in 30% of angler fish samples total mercury concentrations exceeded the maximum level fixed by the European Commission (Hg = 1 microg g(-1) wet wt); for the species for which the maximum level was set to 0.5 microg g(-1) wet wt, concentrations exceeding the prescribed legal limit were observed in 6.4% of bokkem, in 6.6% of pandora, in 20% of megrin, in 12.5% of four-spotted megrim, in 16% of striped mullet, in 5.0% of forkbeard and in 5.3% of picarel samples. In all the different species, mercury was present almost completely in the methylated form, with mean percentages between 70 and 100%. Weekly intake was estimated and compared with the provisional tolerable weekly intake recommended by the FAO/WHO Expert Committee on Food Additives. A high exposure was associated with the consumption of only skates, frost fish and angler fish, thought the consumption of the other species, such as, megrim, four spotted megrim, red fish striped mullet and forkbeard, resulted in a weekly intake slightly below the established provisional tolerable weekly intake.

  5. Effects of methylmercury on approach and avoidance behavior of mallard ducklings

    Science.gov (United States)

    Heinz, G.H.

    1975-01-01

    Mallard ducks were fed a control diet or a diet containing 0.5 or 3 ppm mercury (as methylmercury dicyandiamide) based on the dry feed. These mercury diets are approximately equivalent to 0.1 and 0.6 ppm mercury in a natural succulent diet. I measured for the ducklings the approach behavior in response to a tape-recorded maternal call and the avoidance of a frightening stimulus....There were no significant differences among controls and ducklings from mercury-treated parents in the percentage of ducklings that approached the tape-recorded call. Control ducklings, however, moved back and forth toward the call more than ducklings from mercury-treated parents and also spent more time in the end of the runway near the loudspeaker than ducklings whose parents were fed a diet containing 0.5 ppm mercury....Compared to control ducklings, ducklings from parents fed a diet containing 0.5 or 3 ppm mercury were hyper-responsive in the test of avoidance of a frightening stimulus....Mallard eggs collected in the wild have been found to contain levels of mercury exceeding the 1 ppm (wet-weight) found in the eggs of hens fed a diet containing 0.5 ppm, but there are no reports of mallard eggs collected in the wild that were found to contain as much mercury (6 to 9 ppm) as eggs from hens fed a diet containing 3 ppm mercury. On a dry-weight basis, the concentration of mercury in the eggs was about 6 times as great as that in the feed for ducks fed the 0.5 ppm mercury diet and about 6 to 9 times as great for ducks fed the 3 ppm mercury diet.

  6. A systems approach to risk assessment: Application to methylmercury from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Saroff, L. [Dept. of Energy, Washington, DC (United States); Lipfert, F.W.; Moskowitz, P.D. [Brookhaven National Lab., Upton, NY (United States)

    1995-01-01

    The Department of Energy (DOE) asked Brookhaven National Laboratory (BNL) to perform a probabilistic assessment of the health risks associated with Hg from coal-fired power plants. The objective of the assessment is