The aims of this study include (1) Examine the total mercury and organic mercury concentrations in the muscle and liver tissues of dolphinfish, Coryphaena hippurus that collected in Tungkang and Taitung, Taiwan, in order to understand their safety consumption by human beings due to their high trophic level in a marine ecosystem; (2) Investigate the species difference in comparison to other marine high trophic organisms, e.g. shark, tuna; (3) Look for the pattern of Hg bioaccumulation to see whether it matches the three models defined by Holsbeek et al. A total of 209 samples of Coryphaena hippurus were collected from Tungkang and Taitung. In the 34 samples from Tungkang, males and females were 11 and 23, respectively, whereas 197 samples from Taitung included 92 males and 83 females. Samples from Tungkang were investigated individually, but those from Taitung were pooled by size into 58 samples, 27 males and 24 females. The Hg levels in the samples were wet digested and determined by cold vapor atomic absorption spectrophotometer. The results showed that there was no gender and site difference in the relationship between fork length and body weight in both Tungkang and Taitung samples. The relationship was BW = 0.00005 FL2.7443. The mean and range of total and organic Hg concentrations in muscles and livers of dolphinfish were 0.138 (0.045~0.506) and 0.103 (0.009~0.388), and 0.103 (0.037~0.260) and 0.077 (0.003~0.249), respectively. These concentrations were lower than the WHO food safety level for human consumption and Hg concentrations of shark and tuna. The total Hg concentrations in the muscles were significantly higher than those in livers in both sites. However, only samples of Taitung revealed the organic Hg concentrations of muscles were higher than those of livers. Concerning the site difference, the muscle concentrations of organic Hg, and the liver concentrations of total and organic Hg in Taitung were higher than those of Tungkang. There was positive linear relationship between total and organic Hg as well as in muscle and liver. However, no significant relationship was found between the Hg concentrations and fork length/body weight. The Hg bioaccumulative model of dolphinfish was similiar with Holsbeek et al.¡¦s models. In muscle, the largest sizes of the fish contained the highest organic Hg levels. In companying with no variation of total and inorganic Hg, it looks like Type I model of Holsbeek et al.¡¦s results.

Thesis (Ph. D.)--University of Chicago, 1929. / Lithoprinted. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois."

<p>Interaction between mercury and selenium has previously been observed both in man and in animals. The aim of this work was to study expressions of interaction between mercury and selenium in human K-562 cells. Inorganic and organic forms of mercury and selenium were used and cells were either pre-treated with selenium or simultaneously exposed to selenium and mercury. Concentrations of selenium and mercury chosen were indicated by a study of growth inhibition in the individual compounds: a low concentration of selenium and selenomethionine induced slight cell growth inhibition, while a high concentration resulted in a notable growth inhibition. Two mercury concentrations were chosen: one with minimal toxicity and another with high cell toxicity. In addition, uptake and retention patterns of selenomethionine and selenite differed in both selenocompounds.</p><p>All simultaneous treatments with 3.5 μM methylmercury produced a reduction in cellular mercury with increased selenium concentration. This was particularly obvious in selenite treatments. Growth curves from the simultaneous 3.5 μM methylmercury and selenite treatments indicated protection with increased selenite concentrations. In both exposure protocols, the 5 μM methylmercury treatments were toxic to the cells. </p><p>In both study protocols, cells exposed to selenite and mercuric chloride manifested increased cellular mercury uptake with increased selenium concentration. In all selenite and 35 μM mercuric chloride treatments, no inhibition of growth was observed, while the 50 μM mercuric chloride treatments were toxic to the cells. Selenite-dependent protection was achieved in both exposure protocols when considering the cellular uptake of mercury. With few exceptions, selenomethionine produced similar effects as selenite on mercuric chloride uptake and growth inhibition.</p>

Interaction between mercury and selenium has previously been observed both in man and in animals. The aim of this work was to study expressions of interaction between mercury and selenium in human K-562 cells. Inorganic and organic forms of mercury and selenium were used and cells were either pre-treated with selenium or simultaneously exposed to selenium and mercury. Concentrations of selenium and mercury chosen were indicated by a study of growth inhibition in the individual compounds: a low concentration of selenium and selenomethionine induced slight cell growth inhibition, while a high concentration resulted in a notable growth inhibition. Two mercury concentrations were chosen: one with minimal toxicity and another with high cell toxicity. In addition, uptake and retention patterns of selenomethionine and selenite differed in both selenocompounds. All simultaneous treatments with 3.5 μM methylmercury produced a reduction in cellular mercury with increased selenium concentration. This was particularly obvious in selenite treatments. Growth curves from the simultaneous 3.5 μM methylmercury and selenite treatments indicated protection with increased selenite concentrations. In both exposure protocols, the 5 μM methylmercury treatments were toxic to the cells. In both study protocols, cells exposed to selenite and mercuric chloride manifested increased cellular mercury uptake with increased selenium concentration. In all selenite and 35 μM mercuric chloride treatments, no inhibition of growth was observed, while the 50 μM mercuric chloride treatments were toxic to the cells. Selenite-dependent protection was achieved in both exposure protocols when considering the cellular uptake of mercury. With few exceptions, selenomethionine produced similar effects as selenite on mercuric chloride uptake and growth inhibition.

White muscle samples of bigeye tuna, Thunnus obesus, collected in the Atlantic Ocean and the Indian Ocean were analyzed for total (THg) and organic mercury (OHg) concentrations. A total of 231 white muscle samples showed that THg and OHg concentrations ranged from 0.217 to 0.386 (0.786 ¡Ó 0.386) and 0.143 to 2.222 (0.595 ¡Ó 0.238) mg/kg wet weight, which did not differ with other previous studies. THg and OHg were linearly correlated with fork length (cm) and body weight (kg). The THg and OHg concentrations of 121 bigeye tuna samples collected in the Atlantic Ocean were linearly correlated with fork length, body weight and age. The OHg of 110 bigeye tuna in the Indian Ocean were linearly correlated with fork length, body weight and age, but only the the THg concentrations were linearly correlated with fork length. The average THg and OHg concentrations of bigeye tuna from the Atlantic Ocean showed significantly higher value than those from the Indian Ocean (p< 0.05). Furthermore, the slope of the regression lines between mercury concentrations (THg and OHg) and fork length in the bigeye tuna from the Atlantic Ocean was significantly higher than those from the Indian Ocean (p< 0.05). It¡¦s suggested that different Hg accumulation patterns exist in the two oceans. In the Atlantic and Indian Ocean, 1.7% and 0% of the bigeye tuna, respectively, had OHg concentrations of the muscles above the authorized limit (< 2 mg/kg wet weight) set by the Department of Health, Taiwan, and 13% and 2.7%, respectively, of the levels exceeded the safety food standard (< 1 mg/kg wet weight) set by WHO and FDA. Accordingly, for adult men and women with 65 kg and 55 kg of body weight, the maximum allowable weekly intake of bigeye tuna are suggested to be 170 and 145 g, respectively.

The objects of this study were to investigate the differences of total mercury(THg), organic mercury(OHg) concentrations in the muscles of albacore and bigeye tuna from the Pacific Ocean, and the THg and OHg concentration in the livers , and the trace elements (Cu, Fe, Mn and Zn) in the muscles and livers of albacore, in order to evaluate the bioaccumulative status of the oceanic migratory fishes. Meanwhile, The relationships between mercury concentration and size (length and weight) and age were established, and the differences of mercury concentrations in the tuna between species and geography were examined. And that the safety consumption level was also discussed. One hundred eighty-five albacore and 134 bigeye tuna were sampled from the period October 2001 to April 2006 and from September 2005 to November 2006, respectively, in the Western and Central Pacific Ocean. The results showed that the average THg (mg/kg flesh wt.) and OHg (mg/kg flesh wt.) of muscles were 0.435¡Ó0.145 and 0.279¡Ó0.087, respectively, for albacore, and 0.935¡Ó0.655 and 0.544¡Ó0.396, respectively, for bigeye tuna. The THg and OHg of livers of albacore were 0.426¡Ó0.363 and 0.193¡Ó0.121, respectively. The average OHg percentages of the THg in albacore and bigeye tuna were 67¡Ó19 % and 62¡Ó20 %, respectively. Except there was no significant correlation between OHg and age in the liver of albacore, the THg and OHg in the muscles, and THg in the livers of albacore, and THg in the muscles of bigeye tuna showed a positive correlation with size and age. The THg and OHg levels in the muscles of albacore were lower than those of bigeye tuna, and the accumulative rates of THg and OHg in albacore were lower than those in bigeye tuna. No significant different of muscles-THg and -OHg concentrations of albacore from the four samplind areas. However, the THg and OHg levels in muscle of bigeye tuna showed that north group higher than those in equator. The concentrations of THg were similar in muscle and liver of albacore, but those OHg, Cu, Fe, Mn and Zn concentrations in liver were significantly higher than those in muscle. A detoxificated mechanism may be commenced when the concentration of THg in liver of albacore exceed 0.8 mg/kg, to maintain the muscle concentration of THg at a level about 0.7 mg/kg. The OHg concentrations of all albacore and 88% of bigeye tuna were below WHO food safety standard for migratory fishes(1.0 mg/kg). The consumption amount of albacore and bigeye tuna were no more than 300 and 150g, respectively, will not exceesed the PTWI(provisional tolerable weekly intake) set by WHO, that will not cause any health threat for consumer.

Mercury (Hg) compounds are some of the most toxic compounds of any heavy metal on earth. Due to long-range transport from point sources Hg can be found world-wide in air, soil, water, and living organisms. Mercury compounds can cause a number of adverse effects, with the unborn fetus, infants, and children being most susceptible. Zebrafish (Danio rerio) are an excellent vertebrate model system for toxicological studies, including developmental effects. The overall objective of this research was to investigate the effects of inorganic forms of Hg in zebrafish larvae. Unique accumulation patterns were observed using synchrotron X-ray fluorescence imaging after zebrafish were exposed to one of four Hg compounds (i.e. mercuric chloride, mercury bis-L-cysteineate, methylmercury chloride, methylmercury L-cysteineate). Specifically, we noted chemical form dependant and tissue-specific Hg accumulation including the sensory cells of the olfactory epithelia and the neuromasts. Phenylthiourea (PTU) is commonly used to block zebrafish melanogenesis to generate transparent larvae to aid with enhanced visualization of immunohistochemical and vital stains. It was determined that PTU dramatically alters Hg toxicity through chemical interaction with Hg so that further studies were conducted in the absence of PTU. To investigate the effects of Hg on primary neurons, the immunohistochemistry protocol using anti-acetylated tubulin was performed and the results demonstrated that mercuric chloride damages primary neurons particularly in the olfactory pits. To study potential detoxification of Hg in zebrafish we examined the efficacy of two sequestration agents, dimercaptosuccinic acid and alpha lipoic acid, as well as endogenous selenium. The levels of Hg were not significantly lower following treatment with either sequestration agent under the conditions used in this research. Previous work examining the antagonistic relationship between Hg and selenium has been conducted by dosing animals with both Hg and selenium (Se). We discovered a mixed chalcogenide of the general form HgSxSe(1-x) forming in vivo following exposure to mercuric chloride without the addition of selenium. Indeed the selenium may have been remobilized from natural stores in the pigment spots. The research presented herein demonstrates that the target tissues for Hg depend strongly on chemical form. In particular inorganic Hg can accumulate in a number of important tissues including sensory systems. The formation of insoluble and non-toxic HgSxSe(1-x) in zebrafish larvae suggests that endogenous selenium may play critical roles in modulating toxicity.

Orientador: Wilson de Figueiredo Jardim / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T20:31:57Z (GMT). No. of bitstreams: 1 Bisinoti_MarciaCristina_D.pdf: 1949476 bytes, checksum: a702f967a817c83e250f6e74b334ddd3 (MD5) Previous issue date: 2005 / Doutorado / Quimica Analitica / Doutor em Ciências

O Reservatório Rio Grande, localizado na Região Metropolitana de São Paulo (RMSP), é um importante manancial de abastecimento de água dessa região. Foram analisadas amostras de água de fundo e de sedimentos coletadas nesse reservatório em 4 pontos, em 4 campanhas, de setembro de 2008 a janeiro de 2010, sendo estas quantificadas em relação à concentração de Hg total pela técnica de CV AAS. Em seguida, adaptou-se uma metodologia da literatura para quantificação de Hg orgânico em sedimentos, que consistiu na extração dos compostos organomercuriais com diclorometano em meio ácido e, posterior destruição dos compostos orgânicos com cloreto de bromo. A validação dessa metodologia, em termos de precisão e exatidão, foi realizada por meio da análise dos materiais de referência BCR CRM 580 e IAEA 405. Para avaliação dos mecanismos de metilação e desmetilação de Hg nesse ambiente, foram determinados os seguintes parâmetros físicos e químicos, in situ: pH, temperatura da água, potencial redox (EH), transparência e profundidade. Nos sedimentos foram determinados também a granulometria, carbono orgânico total, bactérias redutoras de sulfato, N total e P total, além de Co, Cu, Fe e Mn. A seleção destes parâmetros esteve relacionada diretamente a fatores que influenciam o comportamento do MeHg em sedimentos e sua zona de transição. Foram encontradas concentrações para Hg total variando entre 1,0 e 71,0 mg kg- 1 e de Hg orgânico entre <10,0 a 47,2 &mu;g kg-1 e taxas de metilação entre 0,06 e 1,4% em sedimentos, ao longo do reservatório. Discutiram-se também as diferentes condições de metilação e suas influências, ao longo do reservatório. Como estudo suplementar, avaliou-se a concentração de outros metais e elementos traço presentes nos sedimentos, por meio da técnica de ativação neutrônica. Foram quantificados os elementos As, Ba, Br, Co, Cr, Cs, Hf, Fe, Na, Rb, Sb, Sc, Zn e os elementos terras raras Ce, Eu, La, Lu, Nd, Sm, Tb e Yb. Os fatores de enriquecimento calculados em relação aos valores da crosta terrestre utilizando-se Sc como elemento normalizador apresentaram valores acima de 2,0 para os elementos As, Br, Sb, U e Zn. Verificou-se uma forte influência antrópica para alguns dos elementos analisados, principalmente nos pontos localizados na entrada do reservatório, que recebem descarga de efluentes domésticos e industriais dos rios que alimentam o reservatório. / The Rio Grande reservoir is located in the metropolitan area of São Paulo and it is a very important water supply for this region. In the present study bottom waters and sediment samples collected in this reservoir, in four sampling points, in four campaigns, from September 2008 to January 2010, were analyzed. Firstly total Hg was determined in sediment and bottom waters by cold vapor atomic absorption technique (CV AAS). Following, the analytical methodology for organic Hg was adapted from literature, where the organomercurial compounds were extracted with dichloromethane in acid medium and subsequent destruction of organic compounds by bromine chloride. The validation of this methodology, in terms of precision and accuracy, was performed by means of IAEA 405 and BCR-CRM 580 reference materials analyses. For methylation and demethylation processes evaluation in this environment, the following physical and chemical parameters were assessed, in situ: pH, water temperature, redox potential (EH), transparency and depth. For the sediment samples, granulometry, total organic carbon, sulphate-reducing bacteria, total N and P, besides the metals Co, Cu, Fe and Mn were evaluated. The selection of these parameters was related to the factors that influence the behavior of MeHg in the sediments and its transition zone. Total Hg ranging from 1.0 to 71.0 mg kg-1 and organic mercury from <10.0 to 47.2 &mu;g kg-1 in sediments and methylation rates from 0.06 to 1.4% were found, along the reservoir. Different methylation conditions along the reservoir and its influences were also discussed. As supplementary study the concentration of some metals and trace elements in the sediments by neutron activation analysis technique was determined. As, Ba, Br, Co, Cr, Cs, Hf, Fe, Na, Rb, Sb, Sc and Zn and rare earth elements Ce, Eu, La, Lu, Nd, Sm and Yb were determined. The enrichment factor in relation to earth crust values using Sc as normalizer element reached values higher than 2.0 for the elements As, Br, Sb, Th, U and Zn, indicating a strong enrichment. A strong anthropogenic influence was verified for some of the elements analyzed, mainly in the points located in the entrance of the reservoir that receives domestic and industrial effluents from the rivers that reach the reservoir.

O Reservatório Rio Grande, localizado na Região Metropolitana de São Paulo (RMSP), é um importante manancial de abastecimento de água dessa região. Foram analisadas amostras de água de fundo e de sedimentos coletadas nesse reservatório em 4 pontos, em 4 campanhas, de setembro de 2008 a janeiro de 2010, sendo estas quantificadas em relação à concentração de Hg total pela técnica de CV AAS. Em seguida, adaptou-se uma metodologia da literatura para quantificação de Hg orgânico em sedimentos, que consistiu na extração dos compostos organomercuriais com diclorometano em meio ácido e, posterior destruição dos compostos orgânicos com cloreto de bromo. A validação dessa metodologia, em termos de precisão e exatidão, foi realizada por meio da análise dos materiais de referência BCR CRM 580 e IAEA 405. Para avaliação dos mecanismos de metilação e desmetilação de Hg nesse ambiente, foram determinados os seguintes parâmetros físicos e químicos, in situ: pH, temperatura da água, potencial redox (EH), transparência e profundidade. Nos sedimentos foram determinados também a granulometria, carbono orgânico total, bactérias redutoras de sulfato, N total e P total, além de Co, Cu, Fe e Mn. A seleção destes parâmetros esteve relacionada diretamente a fatores que influenciam o comportamento do MeHg em sedimentos e sua zona de transição. Foram encontradas concentrações para Hg total variando entre 1,0 e 71,0 mg kg- 1 e de Hg orgânico entre <10,0 a 47,2 &mu;g kg-1 e taxas de metilação entre 0,06 e 1,4% em sedimentos, ao longo do reservatório. Discutiram-se também as diferentes condições de metilação e suas influências, ao longo do reservatório. Como estudo suplementar, avaliou-se a concentração de outros metais e elementos traço presentes nos sedimentos, por meio da técnica de ativação neutrônica. Foram quantificados os elementos As, Ba, Br, Co, Cr, Cs, Hf, Fe, Na, Rb, Sb, Sc, Zn e os elementos terras raras Ce, Eu, La, Lu, Nd, Sm, Tb e Yb. Os fatores de enriquecimento calculados em relação aos valores da crosta terrestre utilizando-se Sc como elemento normalizador apresentaram valores acima de 2,0 para os elementos As, Br, Sb, U e Zn. Verificou-se uma forte influência antrópica para alguns dos elementos analisados, principalmente nos pontos localizados na entrada do reservatório, que recebem descarga de efluentes domésticos e industriais dos rios que alimentam o reservatório. / The Rio Grande reservoir is located in the metropolitan area of São Paulo and it is a very important water supply for this region. In the present study bottom waters and sediment samples collected in this reservoir, in four sampling points, in four campaigns, from September 2008 to January 2010, were analyzed. Firstly total Hg was determined in sediment and bottom waters by cold vapor atomic absorption technique (CV AAS). Following, the analytical methodology for organic Hg was adapted from literature, where the organomercurial compounds were extracted with dichloromethane in acid medium and subsequent destruction of organic compounds by bromine chloride. The validation of this methodology, in terms of precision and accuracy, was performed by means of IAEA 405 and BCR-CRM 580 reference materials analyses. For methylation and demethylation processes evaluation in this environment, the following physical and chemical parameters were assessed, in situ: pH, water temperature, redox potential (EH), transparency and depth. For the sediment samples, granulometry, total organic carbon, sulphate-reducing bacteria, total N and P, besides the metals Co, Cu, Fe and Mn were evaluated. The selection of these parameters was related to the factors that influence the behavior of MeHg in the sediments and its transition zone. Total Hg ranging from 1.0 to 71.0 mg kg-1 and organic mercury from <10.0 to 47.2 &mu;g kg-1 in sediments and methylation rates from 0.06 to 1.4% were found, along the reservoir. Different methylation conditions along the reservoir and its influences were also discussed. As supplementary study the concentration of some metals and trace elements in the sediments by neutron activation analysis technique was determined. As, Ba, Br, Co, Cr, Cs, Hf, Fe, Na, Rb, Sb, Sc and Zn and rare earth elements Ce, Eu, La, Lu, Nd, Sm and Yb were determined. The enrichment factor in relation to earth crust values using Sc as normalizer element reached values higher than 2.0 for the elements As, Br, Sb, Th, U and Zn, indicating a strong enrichment. A strong anthropogenic influence was verified for some of the elements analyzed, mainly in the points located in the entrance of the reservoir that receives domestic and industrial effluents from the rivers that reach the reservoir.