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Indirect cathodic-stripping voltammetric determination of ceftazidime as a mercury salt

Ferreira, V. S.; Zanoni, Maria Valnice Boldrin; Fogg, A. G.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 255-259
ENG
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At accumulation potentials close to +0.1 V at a hanging mercury drop electrode, ceftazidime is accumulated at pH 9.5, probably in a hydrolysed or otherwise chemically altered form, in an anodic process to give an adsorbed mercury salt. The accumulation of this mercury salt allows the indirect cathodic-stripping voltammetric determination of ceftazidime using the reduction peak of the mercury salt at -0.70 V. The high sensitivity of the method coupled with high sample dilution allows ceftazidime to be determined in milk samples at the 28 mu g ml(-1) level without prior separation. In order to determine lower levels of ceftazidime in milk (ca. 10 ng ml(-1)) a separation process would be required. (C) 1998 Elsevier B.V. B.V. All rights reserved.

DEVELOPMENT OF A CHEMICALLY MODIFIED ELECTRODE BASED ON CARBON PASTE AND FUNCTIONALIZED SILICA-GEL FOR PRECONCENTRATION AND VOLTAMMETRIC DETERMINATION OF MERCURY(II)

Aleixo, L. M.; Souza, MDB; Godinho, OES; Neto, G. D.; Gushikem, Y.; Moreira, J. C.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 143-148
ENG
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A mercury-sensitive chemically modified electrode (CME) based on modified silica gel-containing carbon paste was developed. The functional group attached to the silica gel surface was 3-(2-thiobenzimidazolyl)propyl, which is able to complex mercury ions. This electrode was applied to the determination of mercury(II) ions in aqueous solution. The mercury was chemically preconcentrated on the CME prior to voltammetric determination by anodic stripping in the differential-pulse mode. A calibration graph covering the concentration range from 0.08 to 2 mg l-1 was constructed. The precision for six determinations of 0.122 and 0.312 mg l-1 Hg(II) was 3.2 and 2.9% (relative standard deviation), respectively. The detection limit for a 5-min preconcentration period was 0.013 mg l-1. A study for foreign ions was also made.

Fast ultrasound-assisted treatment of urine samples for chronopotentiometric stripping determination of mercury at gold film electrodes

Munoz, RAA; Felix, F. S.; Augelli, M. A.; Pavesi, T.; Angnes, L.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 93-98
ENG
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This work describes an efficient, fast, and reliable analytical methodology for mercury determination in urine samples using stripping chronopotentiometry at gold film electrodes. The samples were sonicated in the presence of concentrated HCl and H2O2 for 15 min in order to disrupt the organic ligands and release the mercury. Thirty samples can be treated over the optimized region of the ultrasonic bath. This sample preparation was enough to allow the accurate stripping chronopotentiometric determination of mercury in the treated samples. No background currents and no passivation of the gold film electrode due to the sample matrix were verified. The samples were also analyzed by cold vapour atomic absorption spectrometry (CV-AAS) and good agreement between the results was verified. The analysis of NIST SRM 2670 (Toxic Metals in Freeze-Dried Urine) also validated the proposed electroanalytical method. Finally, this method was applied for mercury evaluation in urine of workers exposed to hospital waste incinerators. (c) 2006 Elsevier B.V. All rights reserved.

A Preliminary and Qualitative Metallomics Study of Mercury in the Muscle of Fish from Amazonas, Brazil

Moraes, Paula M.; Santos, Felipe A.; Padilha, Cilene C. F.; Vieira, Jose C. S.; Zara, Luiz F.; Padilha, Pedro de M.
Fonte: Humana Press Inc Publicador: Humana Press Inc
Tipo: Artigo de Revista Científica Formato: 195-199
ENG
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 10/51332-5; Processo FAPESP: 09/54856-8; This paper presents preliminary findings for a metallomics study of mercury in the muscle of the fish species from Amazonas, Brazil, after protein separation by two-dimensional polyacrylamide gel electrophoresis and subsequent evaluation of mercury by synchrotron radiation X-ray fluorescence. The fluorescence spectra revealed mercury in two protein spots. The mercury-containing protein spots showed molecular weights of 20.8 +/- 0.7 and 19.8 +/- 0.5 kDa and isoelectric points of 5.6 +/- 0.2 and 7.5 +/- 0.3, respectively.

Seasonal behavior of mercury species in waters and sediments from the Negro River Basin, Amazon, Brazil

Bisinoti, Márcia Cristina; Sargentini Jr., Ézio; Jardim, Wilson F.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 544-553
ENG
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Total (HgT), reactive (HgR) and organic (Hg ORG) mercury species have been quantified in non-filtered waters collected from the Negro River Basin, Amazon (from January/2002 through January/2004), in both black and white water bodies. Black waters presented the highest HgT, HgORG and HgR concentration (29.1 ng L-1, 1.63 ng L-1 and 3.9 ng L-1, respectively), while, white waters presented the lowest HgT, Hg ORG and HgR concentration (8.8 ng L-1, 0.49 ng L-1 and 1.2 ng L-1, respectively). An inverse correlation between HgT and the water level over the basin was obtained, although the HgORG concentration has increased in the first rainy months and then decreased as the water level rose. Total mercury in surface sediments (0-10 cm) ranged from 70 to 271 mg kg-1 being the methylmercury 0.47-1.79 % of this stock. The results indicate that HgR and the labile dissolved organic matter were introduced into the aquatic environment during the flooding season, especially in the earlier stages, thus contributing to mercury methylation. ©2007 Sociedade Brasileira de Química.

Metallomic study of mercury in fish from Amazon region - Brazil

Moraes, P. M.; Santos, F. A.; Padilha, C. F.; Castro, G. R.; Zara, L. F.; Padlha, P. M.; Pirrone, N.
Fonte: E D P Sciences Publicador: E D P Sciences
Tipo: Conferência ou Objeto de Conferência Formato: 2
ENG
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This paper presents preliminary findings for a metallomics study of mercury in the muscle of the fish from Amazonas region - Brazil, after protein separation by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and subsequent evaluation of mercury by Thermal Decomposition and Amalgamation Coupled with Atomic Absorption (TTA-CAAS). It was found that mercury is present in 18 protein spots of dourada muscle (Brachyplatystoma rousseauxii) and 9 protein spots of pacu muscle (Myleus sp.). The protein spots in which they were determined the presence of mercury present molecular weight of 13.5 and 21.4 kDa and isoelectric point of 3.8 and 9.2, respectively.

Towards the abatement of environmental mercury pollution: An electrochemical characterization

Giannetti, B. F.; Moreira, W. A.; Bonilla, S. H.; Almeida, CMVB; Raboczkay, T.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 213-220
ENG
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Electrochemical experiments in acetic acid-acetate buffer (pH 4.5) are conducted in order to understand metallic and ionic mercury adsorption processes on the pyrite surface. The nature as well as the extent of the spontaneous interaction between pyrite and mercuric ions was evaluated. The spontaneous reduction of mercury species onto pyrite surface was confirmed. These results represent a first step for the use of mining wastes rich in pyrite for mercury pollution abatement. (c) 2005 Elsevier B.V. All rights reserved.

Estudo das emissões de mercurio na combustão de carvão mineral brasileiro em leito fluidizado rapido; Assessment of mercury emissions from brazilian coal combustion in fast fluidized bed

Jhon Jairo Ramirez Behainne
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 01/06/2007 PT
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Este trabalho teve o propósito de avaliar as emissões totais de mercúrio produzidas pela combustão de misturas de carvão mineral brasileiro CE-4500 com dolomita em regime de fluidização rápida. Amostras do gás de combustão foram coletadas na chaminé do sistema após o filtro de mangas do combustor, através de uma sonda isocinética de laboratório operada com base nos métodos U.S.E.P.A. n. 29 e ASTM-D-6784 (Ontario-Hydro). Resíduos sólidos gerados pelo processo também foram coletados, e junto com as amostras obtidas na chaminé, foram analisados através da técnica de espectrofotometria de fluorescência atômica de vapor frio. Em onze testes experimentais, obteve-se informação relacionada com os perfis axiais de pressão estática e temperatura, a concentração de O2, CO e NOx nos gases de combustão, o rendimento de captura do separador de partículas do sistema e a eficiência da conversão de carbono no processo. Os resultados do estudo revelaram que, em média, 6% do mercúrio total liberado nos efluentes do processo saiu pela chaminé com o gás de combustão e com as partículas não coletadas pelo filtro de mangas. Adicionalmente foi demonstrado que o valor da relação molar cálcio-enxofre não influencia significativamente nas emissões totais do poluente no gás de combustão. O balanço de mercúrio no processo mostrou um desvio médio de 40%...

Otimização e aplicação de câmaras para medição de fluxos de mercúrio gasoso dissolvido na interface água/atmosfera em lagos da bacia do Rio Negro - AM; Development, validation and application of chambers for mercury fluxes determinations in the water/atmosphere interface over lakes in the Negro River Basin - Amazon region - Brazil

Leonardo Augusto Silvestre Silva
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 31/08/2006 PT
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Neste trabalho, o objetivo principal foi a construção e otimização de câmaras visando a quantificação dos fluxos de mercúrio dissolvido gasoso (MDG), na interface água / atmosfera em lagos da Bacia Hidrográfica do Rio Negro - AM. Foram realizados trabalhos de campo utilizando-se câmaras construídas em acrílico incolor nos quais foram determinadas as concentrações de mercúrio na atmosfera externa e interna da câmara. O ar foi bombeado através de colunas preenchidas com areia de quartzo recoberta com ouro, capazes de pré-concentrar o MDG por amalgamação. A quantificação do mercúrio foi realizada empregando-se a técnica de Espectrometria de Fluorescência Atômica do Vapor Frio (CVAFS), em um equipamento operando embarcado. Em campanha realizada no mês de Janeiro de 2003, os fluxos de MDG registrados no Lago Araca (águas brancas) foram, em pmol m-2 h-1: -20,68; + 8,16 e - 0,54 em períodos sem incidência de luz, e + 29,54 ; + 32,72 em períodos iluminados. Já no Lago Iara (águas negras), os valores encontrados para MDG em períodos sem incidência de luz foram: + 28,77; + 19,00 ; + 22,35, assim como + 5,39 e - 4,85 em períodos iluminados. Os resultados sugerem que os fluxos de MDG nos lagos da Bacia do Rio Negro seguem a tendência de serem invasivos para períodos não iluminados e evasivos para períodos iluminados em águas brancas...

Emissões de mercúrio originárias das queimadas da floresta amazônica e de canaviais; Mercury emission originated from fires of amazon forest and sugar cane

Paula Albernaz Machado Michelazzo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/11/2007 PT
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A influência das queimadas de biomassa sobre as concentrações do mercúrio na atmosfera foi avaliada nas regiões de Piracicaba (SP) (cana-deaçúcar) e Alta Floresta (MT) (floresta amazônica). Os resultados obtidos em Piracicaba para mercúrio gasoso (8,6 ± 4,0 ng m ¿ jun/04; 10,9 ± 5,5 ng m ¿ ago/04 e 8,3 ± 7,6 ng m ¿ fev/05) e particulado (120 ± 53 ng m-3 ¿ jun/04; 435 ± 566 ng m ¿ ago/04 e 143 ± 99 ng m ¿ fev/05) indicam a influência de fontes de emissão de Hg na concentração deste elemento na atmosfera da região. Em Alta Floresta os valores médios de Hg atmosférico para as duas áreas estudadas (4,3 ± 3,5 ng m antes e 40 ± 33 ng m depois da queimada (2004) e 2,1 ± 2,3 ng m antes e 15,0 ± 11,9 ng m depois da queimada (2005)) mostram a influência das queimadas na emissão de Hg na região. A determinação das concentrações de Hg no solo antes e depois da queimada permitiu demonstrar que somente o Hg presente na camada superficial do solo (0-2 cm) pode ser emitido durante as queimadas. A partir das concentrações de Hg no solo e na vegetação foi possível calcular o estoque de Hg na vegetação e no solo (0-1 cm) (4,5 e 9,5 g ha, respectivamente) e os fatores de emissão de Hg para as áreas de 2004 (2...

Monitoring acid-volatile sulphide by a fast scan voltammetric method: application to mercury contamination studies in salt marsh sediments

Carapuça, H. M.; Valega, M.; Pereira, E.; Duarte, A. C.
Fonte: Elsevier Masson Publicador: Elsevier Masson
Tipo: Artigo de Revista Científica
ENG
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The present work demonstrates the application of fast scan linear sweep cathodic stripping voltammetry to the determination of acid-volatile sulphide (AVS) in salt marsh sediments. This approach combines very fast analysis with relatively high sensitivity without the need for additional reagents or derivatization procedures. The purge-and-trap AVS methodology was used. The sulphide content in the trapping NaOH solution was directly measured by voltammetry with a high scan rate (1000 mV s−1). The limit of detection (3σ) was 0.34 μmol L−1 for a deposition time of 5 s. Vertical distribution of AVS in sediments was determined in salt marsh sediments of a Portuguese coastal lagoon vegetated with H. portulacoides and correlated to the total dissolved mercury content in pore waters. At the depth of higher root biomass (around 20 cm), AVS concentrations (range 0.24–24.8 μmol g−1) were low in comparison to other depths, probably due to modifications in sediments that occur in the vicinity of the roots. The highest dissolved mercury concentrations (835 and 675 ng L−1), were found at the surface layer and at 20 cm depth, with an opposite trend from that of AVS. A possible explanation is that root activity reduced AVS concentrations at the depth of higher root biomass and resulted in elevated pore water concentrations of mercury. Concentrations of mercury in pore water from layers above and below the high root biomass were consistently lower (less than 152 ng L−1).

Mercury contamination in sandy soils surrounding an industrial emission source (Estarreja, Portugal)

Inacio, M. M.; Pereira, V.; Pinto, M. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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This study reports the degree and the extent of mercury contamination in sandy soils surrounding a chloralkali plant at Estarreja, Portugal. Total mercury concentration in the soils studied is at a maximum in the upper 5 cm, ranging from 117 to 49,233 μg kg−1. The profile distribution pattern for total mercury together with the results of a sequential extraction suggest that the element is strongly retained by the soil components. An upper limit of acceptable levels of mercury for this area is proposed based both on statistics and regulatory guidelines from other countries. Taking that limit, geostatistical methods were used to delimit a zone of heavy contamination. Atmospheric fall-out seems to be the main source of contamination of the soils studied.

The macrobenthic community along a mercury contamination in a temperate estuarine system (Ria de Aveiro, Portugal)

Nunes, M.; Coelho, J. P.; Cardoso, P. G.; Pereira, M. E.; Duarte, A. C.; Pardal, M. A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
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Mercury is a widely distributed environmental pollutant and a toxic element to all living organisms. This study represents an attempt to evaluate its correlation with the macrobenthic community structure in a temperate estuarine system, the Ria de Aveiro (Portugal). The macrobenthic community structure showed significant differences along the mercury gradient. Overall, the increase of mercury contamination was associated with reduced total abundance, lower species richness, and dominance of tolerant taxa. The polychaetes Hediste diversicolor and Alkmaria romijni, and the isopod Cyathura carinata were associated with high levels of mercury in sediment, while the bivalves Scrobicularia plana, Cerastoderma edule and Abra alba showed higher density in lesser contaminated sites. Furthermore, highly contaminated sites showed substantially lower abundances of surface-deposit feeders and herbivores, and higher abundances of subsurface-deposit feeders and omnivores. Salinity was also a significant factor affecting the community, being responsible for seasonal variations in the macrobenthic assemblages.

Mercury Removal from Aqueous Solution and Flue Gas by Adsorption on Activated Carbon Fibres

Nabais, Joao; Carrott, Peter; Ribeiro Carrott, Manuela
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica Formato: 28711 bytes; application/pdf
ENG
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The use of two activated carbon fibres, one laboratorial sample prepared from a commercial acrylic textile fibre and one commercial sample of Kynol1, as prepared/received and modified by reaction with powdered sulfur and H2S gas in order to increase the sulfur content were studied for the removal of mercury from aqueous solution and from flue gases from a fluidized bed combustor. The sulfur introduced ranged from 1 to 6 wt.% depending on the method used. The most important parameter for the mercury uptake is the type of sulfur introduced rather than the total amount and it was found that the H2S treatment of ACF leads to samples with the highest mercury uptake, despite the lower sulfur amount introduced. The modified samples by both methods can remove HgCl2 from aqueous solutions at pH 6 within the range 290–710 mg/g (ACF) which can be favourably compared with other studies already published. The use of a filter made with an activated carbon fibre modified by powdered sulfur totally removed the mercury species present in the flue gases produced by combustion of fossil fuel.

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

AMORIM,MARÚCIA I. M.; MERGLER,DONNA; BAHIA,MARCELO O.; DUBEAU,HÉLÈNE; MIRANDA,DANIELA; LEBEL,JEAN; BURBANO,ROMMEL R.; LUCOTTE,MARC
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2000 EN
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The mercury rejected in the water system, from mining operations and lixiviation of soils after deforestation, is considered to be the main contributors to the contamination of the ecosystem in the Amazon Basin. The objectives of the present study were to examine cytogenetic functions in peripheral lymphocytes within a population living on the banks of the Tapajós River with respect to methylmercury (MeHg) contamination, using hair mercury as a biological indicator of exposure. Our investigation shows a clear relation between methylmercury contamination and cytogenetic damage in lymphocytes at levels well below 50 micrograms/gram, the level at which initial clinical signs and symptoms of mercury poisoning occur. The first apparent biological effect with increasing MeHg hair level was the impairment of lymphocyte proliferation measured as mitotic index (MI). The relation between mercury concentration in hair and MI suggests that this parameter, an indicator of changes in lymphocytes and their ability to respond to culture conditions, may be an early marker of cytotoxicity and genotoxicity in humans and should be taken into account in the preliminary evaluation of the risks to populations exposed in vivo. This is the first report showing clear cytotoxic effects of long-term exposure to MeHg. Although the results strongly suggest that...

Semiquantitative mercury determination in fish: a tool for poisoning prevention

YALLOUZ,ALLEGRA V.; CALIXTO,TATIANA; HACON,SANDRA
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2002 EN
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Human exposure to mercury intoxication through contaminated fish ingestion has been well studied, mainly among Japanese population. The Brazilian population, particulaly in the Amazon region, is now in focus due to findings of fish contamination. Major health impacts caused by mercury affect mostly people who have a regular fish diet. A continuous checking for mercury content in the most consumed fish could prevent human intoxication. A simple, non-instrumental method to allow a continuous checking of the mercury content in fish was developed. Based on this method, we are proposing a prevention action where community agents can be trained to perform fish analysis. Technical Schools and Universities located nearby the affected areas would be in charge of quality control programs for the fish analysis as well as for the selection, training and update for operators.

Long-term loss of color vision after exposure to mercury vapor

Feitosa-Santana,C.; Costa,M.F.; Lago,M.; Ventura,D.F.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2007 EN
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We evaluated the color vision of 24 subjects (41.6 ± 6.5 years; 6 females) who worked in fluorescent lamp industries. They had been occupationally exposed to mercury vapor (10.6 ± 5.2 years) and had been away from the source of exposure for 6.4 ± 4.04 years. Mean urinary concentration of mercury was 40.6 ± 36.4 µg/g creatinine during or up to 1 year after exposure and 2.71 ± 1.19 µg/g creatinine at the time of color vision testing or up to 1 year thereafter. All patients were diagnosed with chronic mercury intoxication, characterized by clinical symptoms and neuropsychological alterations. A control group (N = 36, 48.6 ± 11.9 years, 10 females, 1.5 ± 0.47 µg mercury/g creatinine) was subjected to the same tests. Inclusion criteria for both groups were Snellen VA 20/30 or better and absence of known ophthalmologic pathologies. Color discrimination was assessed with the Farnsworth D-15 test (D-15) and with the Lanthony D-15d test (D-15d). Significant differences were found between the two eyes of the patients (P < 0.001) in both tests. Results for the worst eye were also different from controls for both tests: P = 0.014 for D-15 and P < 0.001 for D-15d. As shown in previous studies, the D-15d proved to be more sensitive than the D-15 for the screening and diagnosis of the color discrimination losses. Since color discrimination losses were still present many years after the end of exposure...

Comparative effects of organic and inorganic mercury on in vivo dopamine release in freely moving rats

Faro,L.R.F.; Rodrigues,K.J.A.; Santana,M.B.; Vidal,L.; Alfonso,M.; Durán,R.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2007 EN
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The present study was carried out in order to compare the effects of administration of organic (methylmercury, MeHg) and inorganic (mercury chloride, HgCl 2 ) forms of mercury on in vivo dopamine (DA) release from rat striatum. Experiments were performed in conscious and freely moving female adult Sprague-Dawley (230-280 g) rats using brain microdialysis coupled to HPLC with electrochemical detection. Perfusion of different concentrations of MeHg or HgCl 2 (2 µL/min for 1 h, N = 5-7/group) into the striatum produced significant increases in the levels of DA. Infusion of 40 µM, 400 µM, or 4 mM MeHg increased DA levels to 907 ± 31, 2324 ± 156, and 9032 ± 70% of basal levels, respectively. The same concentrations of HgCl 2 increased DA levels to 1240 ± 66, 2500 ± 424, and 2658 ± 337% of basal levels, respectively. These increases were associated with significant decreases in levels of dihydroxyphenylacetic acid and homovallinic acid. Intrastriatal administration of MeHg induced a sharp concentration-dependent increase in DA levels with a peak 30 min after injection, whereas HgCl 2 induced a gradual, lower (for 4 mM) and delayed increase in DA levels (75 min after the beginning of perfusion). Comparing the neurochemical profile of the two mercury derivatives to induce increases in DA levels...

Performance on neurological development tests by riverine children with moderate mercury exposure in Amazonia, Brazil

Tavares,Lydia Maria Bocayuva; Câmara,Volney Magalhães; Malm,Olaf; Santos,Elisabeth C. de Oliveira
Fonte: Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz Publicador: Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2005 EN
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The nervous system can be damaged when the population is exposed to methyl mercury (MeHg) by ingesting fish, and children deserve special attention due to their increased susceptibility as compared to adults. A comparative cross-sectional study was performed in order to investigate the use of a battery of neurological development tests in two groups of 209 riverine children from 3 to 7 years old: a group exposed to moderate levels of MeHg (n = 75) and a control group (n = 134). The study included a questionnaire, the collection of scalp hair samples for determination of total mercury concentration, and performance on a test for evaluating neurological function in children. Riverine children presented higher exposure to MeHg (mean hair Hg = 5.37 ± 3.35µg.g-1) in comparison to the control group (mean Hg = 2.08 ± 1.37µg.g-1). Both groups showed a high proportion of children with what was considered "non-normal" performance, suggesting that the results could not be related to mercury exposure and that this type of test presented limitations for use with river-dwelling Amazon communities.

Evaluation of mercury contamination in sediments from Santos - São Vicente Estuarine System, São Paulo State, Brazil

Hortellani,Marcos Antonio; Sarkis,Jorge Eduardo Souza; Bonetti,Jarbas; Bonetti,Carla
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2005 EN
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The distribution of mercury contamination in the Santos - São Vicente Estuarine System was observed through the analysis of 31 sediments samples collected from that system, including mangrove areas under urban, industrial and harbor influence zones. The range of values obtained was between 0.04 and 1.19 µg g -1. About 90% of samples presented Hg > 0.13 µg g-1 levels, which is the limit established by Canadian legislation and adopted by the environmental control agency of São Paulo State - Brazil (CETESB), below which no adverse effect on the biological community has been observed. About 35% of these samples presented concentrations of Hg > 0.70 µg g-1, the probable level of occurrence of adverse effect on the biological community. These results indicate an increase in the mercury levels caused by industrial, port and urban activities. A statistical study was carried out, using the SPSS-10.0 software, to verify relationships among all the investigated parameters. Normalization of mercury with mud content was used to detect the degree of mercury contamination in this area.