RESUMO
Bioaccumulation of mercury and methylmercury in fish represents a serious risk to human beings. Extreme climate events like droughts may increase the trophic transfer of contaminants and net methylation of mercury. The present study assessed the influence of the 2014 drought on total mercury and methylmercury levels in fish from the lower Paraiba do Sul river basin. Contaminant levels were compared for Pimelodus fur, Pachyurus adspersus, Pimelodella lateristriga, Oligosarcus hepsetus, and Crenicichla lacustris captured in five sites in 2013 (Nâ¯=â¯212) and 2014 (Nâ¯=â¯231). The results indicate that levels of contaminants were higher during the drought in most species. Rainfall was weakly and negatively correlated with total mercury levels in most of the species. The weak relationship between these two variables was due to the indirect influence of rainfall on mercury bioaccumulation. In summary, drought increased the levels of two contaminants in fish.
Assuntos
Secas , Monitoramento Ambiental , Peixes/metabolismo , Mercúrio/análise , Compostos de Metilmercúrio/análise , Animais , Brasil , Perciformes/metabolismo , Rios , Poluentes Químicos da Água/análiseRESUMO
Total mercury (THg) concentrations measured in two freshwater shrimp species (Macrobrachium depressimanum and Macrobrachium jelskii) showed a relationship with the location of artisanal and small-scale gold mining (ASGM) from the Madeira River Basin, Western Amazon. Between August 2009 and May 2010, 212 shrimp samples were collected in the confluence of the Madeira River with three of its tributaries (Western Amazon). THg concentration was quantified in the exoskeleton, hepatopancreas and muscle tissue of the shrimps by cold vapor atomic absorption spectrophotometry. There were no significant differences between the two shrimp species when samples came from the Madeira River, but Hg concentrations were significantly lower in a tributary outside the influence of the gold mining area. Average THg concentrations were higher in the hepatopancreas (up to 160.0 ng g-1) and lower in the exoskeleton and muscle tissue (10.0-35.0 ng g-1 and < 0.9-42.0 ng g-1, respectively). Freshwater shrimps from the Madeira River respond to local environmental levels of Hg and can be considered as biomonitors for environmental Hg at this spatial scale. These organisms are important for moving Hg up food webs including those that harbor economic significant fish species and thus enhancing human exposure.
Assuntos
Ouro , Mercúrio/análise , Mineração , Palaemonidae , Poluentes Químicos da Água/análise , Exoesqueleto/química , Animais , Brasil , Monitoramento Ambiental , Hepatopâncreas/química , Músculos/química , RiosRESUMO
This is one of the first studies to evaluate the effect of biometric variables (total length and weight), diet, and abiotic matrices (sediment and water column) on the bioaccumulation of methylmercury in tissues (muscle, liver, and gills) of four fish (two carnivore-invertivores, Pimelodus fur and Pachyurus adspersus; one carnivore-piscivore, Oligosarcus hepsetus; and one omnivore, Pimelodella lateristriga) in the lower section of a river in southeastern Brazil. Samples of fish (n = 120), water (n = 5) and sediment (n = 5) were collected at five sites characterized by pollution with mercury due to the use of organomercury fungicides and stream bed gold mining, commonly carried out in that section of the river in the 1980s. The results show that biometric variables are strongly correlated with methylmercury levels in muscle (r = 0.61, p < 0.0005) of P. fur. As a rule, concentrations of total mercury and methylmercury did not vary considerably between the organs of the species of different food habits, because of the environmental conditions in the study area. Despite the low concentrations of mercury in sediments (<0.05 mg kg-1 wet. wt), this compartment is a representative source of this pollutant for the organisms investigated, due to the close contact these animals keep with it in view of the low water columns in that section of the river.
Assuntos
Monitoramento Ambiental , Peixes/metabolismo , Cadeia Alimentar , Compostos de Metilmercúrio/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Brasil , Brânquias/química , Ouro , Mercúrio/análise , Mineração , Rios , Poluentes Químicos da Água/análiseRESUMO
Damming rivers to construct hydroelectric reservoirs results in a series of impacts on the biogeochemical Hg cycle. For example, modifying the hydrodynamics of a natural watercourse can result in the suspension and transport of Hg deposits in the water column, which represents an exposure risk for biota. The objective of this study was to evaluate the influences of seasonality on the dispersion of total Hg in the Hydroelectric Power Plant (HPP)-Samuel Reservoir (Porto Velho/Brazil). Sampling campaigns were performed during the three following hydrological periods characteristic of the region: low (Oct/2011), ebbing (May/2012), and high (Feb/2013) water. Sediment profiles, suspended particulate matter (SPM), and aquatic macrophytes (Eicchornia crassipes and Oryza spp.) were collected, and their Hg concentrations and isotopic and elemental C and N signatures were determined. The drainage basin significantly influenced the SPM compositions during all the periods, with a small autochthonous influence from the reservoir during the low water. The highest SPM Hg concentrations inside the reservoir were observed during the high water period, suggesting that the hydrodynamics of this environment favor the suspension of fine SPM, which has a higher Hg adsorption capacity. The Hg concentrations in the sediment profiles were ten times lower than those in the SPM, indicating that large particles with low Hg concentrations were deposited to form the bottom sediment. Hg concentrations were higher in aquatic macrophyte roots than in their leaves and appeared to contribute to the formation of SPM during the low water period. In this environment, Hg transport mainly occurs in SPM from the Jamari River drainage basin, which is the primary source of Hg in this environment.
Assuntos
Sedimentos Geológicos/análise , Mercúrio/análise , Material Particulado/análise , Centrais Elétricas , Rios/química , Poluentes Químicos da Água/análise , Brasil , Monitoramento Ambiental , Sedimentos Geológicos/química , Mercúrio/química , Material Particulado/químicaRESUMO
Indigenous, introduced and farmed fish species were collected from the Jaguaribe Basin, NE Brazil to assess total and methyl mercury concentrations in muscle tissue and to determine its relationship with fish origin. The results obtained from introduced species were compared to the Hg content of their original area of occurrence, which is located in the Amazon region. Farmed and wild individuals of Oreochromis niloticus (tilapia) were also compared. Introduced species presented lower Hg contents compared to their Amazonian counterparts. Wild individuals of O. niloticus also presented higher Hg contents than farmed individuals with similar sizes. However, methyl Hg concentrations were not significantly different between the two groups. Total Hg and methyl Hg concentrations were higher in carnivorous species, especially those from the Amazon region, and surpassed the Brazilian guidelines for fish consumption. Based on their Hg content, Jaguaribe basin fish do not pose a significant threat to human consumption.
Assuntos
Peixes/fisiologia , Mercúrio/análise , Rios/química , Poluentes Químicos da Água/análise , Animais , Brasil , Ciclídeos , Monitoramento Ambiental , Pesqueiros , Contaminação de Alimentos/análise , Sedimentos Geológicos/química , Músculo Esquelético/químicaRESUMO
Mercury is a xenobiotic metal that is a highly deleterious environmental pollutant. The biotransformation of mercury chloride (HgCl2) into methylmercury chloride (CH3HgCl) in aquatic environments is well-known and humans are exposed by consumption of contaminated fish, shellfish and algae. The objective of the present study was to determine the changes induced in vitro by two mercury compounds (HgCl2 and CH3HgCl) in cultured human lymphocytes. Short-term human leukocyte cultures from 10 healthy donors (5 females and 5 males) were set-up by adding drops of whole blood in complete medium. Cultures were separately and simultaneously treated with low doses (0.1 to 1000 microg/l) of HgCl2 and CH3HgCl and incubated at 37 degrees C for 48 h. Genotoxicity was assessed by chromosome aberrations and polyploid cells. Mitotic index was used as a measure of cytotoxicity. A significant increase (P < 0.05) in the relative frequency of chromosome aberrations was observed for all concentrations of CH3HgCl when compared to control, whether alone or in an evident sinergistic combination with HgCl2. The frequency of polyploid cells was also significantly increased (P < 0.05) when compared to control after exposure to all concentrations of CH3HgCl alone or in combination with HgCl2. CH3HgCl significantly decreased (P < 0.05) the mitotic index at 100 and 1000 microg/l alone, and at 1, 10, 100, and 1000 microg/l when combined with HgCl2, showing a synergistic cytotoxic effect. Our data showed that low concentrations of CH3HgCl might be cytotoxic/genotoxic. Such effects may indicate early cellular changes with possible biological consequences and should be considered in the preliminary evaluation of the risks of populations exposed in vivo to low doses of mercury.
Assuntos
Linfócitos/efeitos dos fármacos , Compostos de Metilmercúrio/toxicidade , Feminino , Humanos , Masculino , Índice Mitótico , Testes de MutagenicidadeRESUMO
Mercury is a xenobiotic metal that is a highly deleterious environmental pollutant. The biotransformation of mercury chloride (HgCl2) into methylmercury chloride (CH3HgCl) in aquatic environments is well-known and humans are exposed by consumption of contaminated fish, shellfish and algae. The objective of the present study was to determine the changes induced in vitro by two mercury compounds (HgCl2 and CH3HgCl) in cultured human lymphocytes. Short-term human leukocyte cultures from 10 healthy donors (5 females and 5 males) were set-up by adding drops of whole blood in complete medium. Cultures were separately and simultaneously treated with low doses (0.1 to 1000 æg/l) of HgCl2 and CH3HgCl and incubated at 37°C for 48 h. Genotoxicity was assessed by chromosome aberrations and polyploid cells. Mitotic index was used as a measure of cytotoxicity. A significant increase (P < 0.05) in the relative frequency of chromosome aberrations was observed for all concentrations of CH3HgCl when compared to control, whether alone or in an evident sinergistic combination with HgCl2. The frequency of polyploid cells was also significantly increased (P < 0.05) when compared to control after exposure to all concentrations of CH3HgCl alone or in combination with HgCl2. CH3HgCl significantly decreased (P < 0.05) the mitotic index at 100 and 1000 æg/l alone, and at 1, 10, 100, and 1000 æg/l when combined with HgCl2, showing a synergistic cytotoxic effect. Our data showed that low concentrations of CH3HgCl might be cytotoxic/genotoxic. Such effects may indicate early cellular changes with possible biological consequences and should be considered in the preliminary evaluation of the risks of populations exposed in vivo to low doses of mercury.
Assuntos
Feminino , Humanos , Masculino , Linfócitos/efeitos dos fármacos , Compostos de Metilmercúrio/toxicidade , Índice Mitótico , Testes de MutagenicidadeRESUMO
Here we describe two new cases of complete deficiency of factor I (fI) in two sisters from a consanguineous Brazilian family. The eldest sibling (20-year-old) developed systemic lupus erythematosus (SLE) early during childhood while the youngest had been committed on several occasions owing to repeated infections although she was asymptomatic for auto-immune diseases. We also detected lower concentrations of C3 and factor B in both sisters. Biological functions dependent on complement activation such as the production of opsonins and killing of phagocytozed micro-organisms, chemotactic factors and haemolytic activity were all significantly reduced in both probands. Consistent with the absence of fI and low levels of fH, a deregulated production of C3b was observed by bidimensional electrophoresis in sera of both the probands.
Assuntos
Infecções Bacterianas/complicações , Transtornos de Proteínas de Coagulação/genética , Transtornos de Proteínas de Coagulação/imunologia , Fator H do Complemento/metabolismo , Fibrinogênio/genética , Lúpus Eritematoso Sistêmico/complicações , Adulto , Inibição de Migração Celular , Células Cultivadas , Pré-Escolar , Transtornos de Proteínas de Coagulação/complicações , Ativação do Complemento , Complemento C3/metabolismo , Complemento C3b/metabolismo , Saúde da Família , Feminino , Fibrinogênio/metabolismo , Predisposição Genética para Doença , Humanos , Imunoeletroforese Bidimensional , FagocitoseRESUMO
Mercury is being released in the Amazon in an abusive way due to goldmining activities. The Tapajós river basin was the first to be intensively exploited in the modern Amazon gold rush. Fish and hair samples as the best indicators of human methylmercury contamination were investigated in the main cities and villages along the Tapajós river basin. The upper basin has typical fish fauna with much larger carnivorous fish with higher mercury levels reaching an average value of 0.69 microgram.g-1 wet wt. in 43 fish. This was accompanied by high levels in hair of the human population living in the same area. The maximum hair value reach 151 micrograms.g-1 dry wt. with two villages presenting an average value close to 25 micrograms.g-1 dry wt. An analytical laboratory intercalibration exercise was performed between Japanese and Brazilian laboratories for total mercury analysis. Critical fish, areas, and more exposed human groups are identified.
Assuntos
Peixes , Cabelo/química , Mercúrio/análise , Compostos de Metilmercúrio/análise , Poluentes Químicos da Água/análise , Animais , Brasil , Contaminação de Alimentos , Água Doce , Ouro , Humanos , MineraçãoRESUMO
OBJECTIVE: Although commonly used, the 1982 revised criteria for the classification of Systemic Lupus Erythematosus (SLE) have not been completely evaluated in pediatric patients. This study was aimed at evaluating the sensitivity and specificity of the 1982 revised criteria when applied to pediatric patients. METHODS: One hundred and three children with SLE and 101 children with other rheumatic diseases were selected from 5 rheumatology centers in Brazil. Diagnosis of SLE by the 1982 criteria were compared with our clinical diagnosis. The diagnosis of other diseases was made according to internationally accepted classification criteria or, when these were not available, according to the physician's own experienced judgement. RESULTS: The median number of criteria fulfilled by the patients with SLE and the controls were 6 and 1, respectively. The most common criteria observed in children with SLE were: abnormal antinuclear antibody titers (94%), arthritis (83%), immunologic disorder (83%), hematologic disorder (70%), malar rash (67%), and photosensitivity (58%). When the immunologic disorder was broken down into its constituent elements, antibodies to dsDNA and Sm were observed in 73.0% (65/89) and 31.4% (15/48), respectively. The sensitivity and specificity observed were 96% and 100%, respectively. CONCLUSION: The 1982 classification criteria can be successfully applied to children with SLE. These criteria may serve as a basis for multi-center collaborative studies on children with SLE.