Regina Celi Sarkis Müller

Comparative study of human exposure to mercury in riverside communities in the Amazon region

Four populations in the Amazon area were selected for a comparative study of mercury-exposed and non-exposed populations: São Luiz do Tapajós, Barreiras, Panacauera, and Pindobal Grande. The highest mercury levels in human hair samples were found in São Luiz do Tapajós and Barreiras, greatly exceeding the limits established by the World Health Organization. Panacauera showed an intermediate level below 9 microg/g. This was the first comparative and simultaneous evaluation of mercury exposure in the Amazon area. Also, thanks to this type of monitoring, we were able to eliminate the uncertainties about the reference dose. On the basis of these data, we can conclude that the mercury levels detected in exposed populations of the Tapajós River basin may be dangerous not only because they are above the World Health Organization limits, but also because the simultaneous mercury detection in non-exposed populations with similar characteristics provided a valid control and revealed lower mercury levels. Our results support the importance of continuous monitoring in both exposed and non-exposed populations.

Evaluation of total mercury concentrations in fish consumed in the municipality of Itaituba, Tapajós River Basin, Pará, Brazil.

The environmental exposure to mercury by riverine and Indian communities can occur through the ingestion of fish and products contaminated by mercury compounds. The present study aims to evaluate the total mercury concentration in the different fish species most consumed in the municipality of Itaituba, Tapajós river basin, where there are intense gold-mining activities. These fish samples were analyzed by atomic absorption spectrophotometry by cold vapor technique, Automatic Mercury Analyzer HG-3500. The largest mercury concentrations were found in the carnivorous species ranging from 112.4 to 2250 microg/g, while the detritivorous, herbivorous and omnivorous species presented total mercury levels ranging from 3.2 to 309.8 microg/g, which is below the limit established by the World Health Organization. This paper also reports and identifies which species are more polluted and present a statistical relationship among concentration and weight of the carnivorous species studied in detail, Brachyplatystoma flavicans (dourada) (r2 = 0.691) and Pseudoplatystoma sp. (surubim) (r2 = 0.654).

Correlation between mercury and selenium concentrations in Indian hair from Rondônia State, Amazon region, Brazil

Total mercury and selenium concentrations were determined in hair samples collected from Wari (Pacaás Novos) Indians living in Doutor Tanajura village, Gujará-Mirim city, Rondĵnia State. The mercury concentrations in some samples are much higher than the values determined in samples from individuals not exposed to mercury contamination, occupationally or environmentally. The selenium concentrations are in the normal range. A correlation was observed between the mercury and selenium concentration and the values of the molar ratio approach 1 at low Hg concentrations. This fact is related to the equimolar complex formed by [(Hg-Se)n]m-Seleprotein P, which can decrease the bioavailable mercury in the organism.

Determinação direta de selênio em água de coco e em leite de coco utilizando espectrometria de absorção atômica com atomização eletrotérmica em forno de grafite

Selenium is both essential and toxic to man and animals, depending on the concentration and the ingested form. Most fruits and vegetables are poor sources of selenium, but coconut can be a good selenium source. Samples were suspended (1 + 4 v/v) in a mixture of tertiary amines soluble in water (10% v/v CFA-C). This simple sample treatment avoided contamination and decreased the analysis time. The standard additions method was adopted for quantification. The action of the autosampler was improved by the presence of the amines mixture in the suspension. A Varian model AA-800 atomic absorption spectrometer equipped with a graphite furnace and a GTA 100 autosampler was used for selenium determination in coconut water and coconut milk. Background correction was performed by means of the Zeeman effect. Pyrolytically coated graphite tubes were employed. Using Pd as chemical modifier, the pyrolysis and the atomization temperatures were set at 1400 and 2200oC, respectively. For six samples, the selenium concentration in coconut water varied from 6.5 to 21.0 mg L-1 and in coconut milk from 24.2 to 25.1 mg L-1. The accuracy of the proposed method was evaluated by an addition-recovery experiment and all recovered values are in the 99.5-102.3% range. The main advantage of the proposed method is that it can be directly applied without sample decomposition.

Mercury Speciation in Hair of Children in Three Communities of the Amazon, Brazil

Children from riverside communities located downstream of gold mining areas may be chronically exposed to relatively high levels of MeHg through the consumption of fish of this region. The objective of this study was to evaluate and compare levels of THg and MeHg in hair of children less than 12 years in communities near mines in the municipality of Itaituba and in communities far from prospecting areas in the city of Abaetetuba. The communities of Itaituba (Barreiras and São Luiz do Tapajós) had THg mean levels of 5.64 ± 5.55 μg·g−1 (0.43–27.82) and 11.41 ± 7.16 μg.g−1 (1.08–28.17), respectively, and an average count of MeHg relative to THg of 92.20% and 90.27%, respectively. In the Maranhão community, the THg average concentrations results were 2.27 ± 2.11 μg·g−1 (0.13–9.54) and the average values were 93.17% for MeHg. Children of Itaituba had average levels of mercury above the limit established by the World Health Organization (10 μg·g−1) and the strong correlation coefficient between the communities (R = 0.968 and P = 0.0001) suggests the hair as an excellent biomarker of human exposure to organic mercury in riverside populations of the Tapajós, which has the intake of fish daily as main source of protein dietary.

Determination of total mercury in workers’ urine in gold shops of Itaituba, Pará State, Brazil

Gold extraction and its commercialization in the Amazon region is mainly by rudimentary procedures. Therefore, during the process of extraction and recovery of this precious metal, large amounts of mercury vapors are thrown into the environment. This paper is an attempt to establish a correlation between the concentration of total mercury in the urine of workers at the gold shop in the Municipality of Itaituba, Pará, and the information related to the lifestyles of each individual studied. Through statistical analysis, it was possible to divide the workers into three groups: people with normal mercury concentrations, [Hg] < or = 10 ppb, (29%); with concentrations at the biological limit of tolerance, [Hg] up to 50 ppb, (49%); and contaminated people, [Hg] > or = 50 ppb (22%). It may be concluded that fish consumption, time of alcohol consumption, number of amalgam fillings, as well as working hours, are important variables when evaluating mercurial contamination of people who are occupationally exposed to mercury vapors.

Classification of honeys from Pará State (Amazon region, Brazil) produced by three different species of bees

Vinte e sete amostras de mel, produzidas em dez cidades do Estado do Para (Regiao Amazonica, norte do Brasil) por tres especies diferentes de abelhas (Apis mellifera, Melipona fasciculata e Melipona flavoneata), foram analisadas em seus teores de elementos minerais (Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Sr e Zn) e alguns parâmetros fisicoquimicos (cor, umidade, densidade, pH, solidos insoluveis e soluveis totais, cinzas, condutividade eletrica, indice de formol, acidez livre, hidroximetilfurfural, acucares redutores e totais e sacarose). Os teores minerais foram determinados via espectrometria de emissao atomica por plasma acoplado indutivamente (ICP OES) e as analises dos parâmetros fisico-quimicos seguiram metodologias oficiais. Os resultados das analises fisico-quimicas apresentaram-se de acordo com a legislacao nacional e internacional, bem como com outros trabalhos similares ao redor do mundo. A analise estatistica multivariada (analise por agrupamento hierarquico (HCA) e por componentes principais (PCA)) foi aplicada aos resultados dos teores metalicos e aos parâmetros fisico-quimicos, sendo possivel a separacao das amostras de mel conforme a especie produtora.

Avaliação do uso da casca do fruto e das folhas de Caesalpinia ferrea Martius como suplemento nutricional de Fe, Mn e Zn

As plantas medicinais podem ser usadas como fontes alternativas de nutrientes minerais na dieta alimentar. Elementos como ferro, manganes e zinco apresentam biodisponibilidade variavel em funcao de suas formas quimicas (especies) presentes em um alimento. Este trabalho tem como objetivo avaliar o teor e a biodisponibilidade de ferro, manganes e zinco em extratos da casca do fruto e das folhas de Caesalpinia ferrea Martius por Espectrometria de Absorcao Atomica com Chama (FAAS). Os agentes extratores testados foram as solucoes de NaOH 0,05 mol. L-1, tampao Tris-HCl 0,05 mol.L-1 (pH= 8), tampao Tris-HCl 0,05 mol.L-1 (pH = 8) em dodecil sulfato de sodio (SDS) 1% (m/v), HCl 0,05 mol.L-1 e agua quente (60 oC). A casca do fruto e as folhas de Caesalpinia ferrea Martius apresentaram niveis altos de ferro e manganes quando comparados aos de outras plantas medicinais. Os elementos estudados mostraram predominante associacao com compostos de alta e baixa massa molecular, especies soluveis e insoluveis em agua. Dentre os elementos analisados, o ferro apresentou melhor biodisponibilidade na casca do fruto e nas folhas. Manganes e zinco se mostraram mais biodisponivel nas folhas. A casca do fruto e as folhas de Caesalpinia ferrea Martius podem ser uma fonte alternativa de ferro, manganes e zinco na dieta alimentar.

Classificação multivariada de ervas medicinais da Região Amazônica e suas infusões de acordo com sua composição mineral

In this study, the mineral composition of leaves and teas of medicinal plants was evaluated. Ca, Cu, Fe, Mg, Mn e Zn were determined in the samples using flame atomic absorption spectrometry. Principal component analysis was applied to discriminate the samples studied. The samples were divided within the 2 groups according to their mineral composition. Copper and iron were the variables that contributed most to the separation of the samples followed by Ca, Mg, Mn and Zn. The information in the principal component analysis was confirmed by the dendrogram obtained by hierarchical cluster analysis.

Avaliação de minerais em plantas medicinais amazônicas

Amazonia brasileira oferece um apreciavel potencial de plantas com propriedades terapeuticas, embora a maioria seja pouco conhecida. Dessa forma, com o objetivo de verificar a potencialidade nutricional de ervas medicinais, determinou-se a concentracao de Ca, Mg, Fe, Cu e Zn nas folhas e nos chas das especies: Piper callosum Ruiz & Pav., Piperaceae, Mikania lindleyana DC., Asteraceae e Arrabidaea chica (Humb. & Bonpl.) B. Verl., Bignoniaceae. As amostras de plantas depois de terem sido processadas, foram submetidas a digestao e em seguida realizada as leituras dos metais em um espectrofotometro de absorcao atomica. Para o cha de Arrabidaea chica foram detectados teores de Ca (6955 a 20058 mg/L), Mg (2390 a 3094 mg/L) e Fe (40 a 61 mg/L). Para o cha de Mikania lindleyana alem da presenca de altos valores de Ca (17722 a 22336 mg/L), Mg (4531 a 9370 mg/L) e Fe (20 a 87 mg/L) foram encontrados de 7 a 16 mg/L de Cu e 9 a 41 mg/L de Zn. O cha do Piper callosum apresentou em media 2036 a 4344 mg/L de Ca, 618 a 4023 mg/L de Mg e 39 a 60 mg/L de Fe. Comparando-se os resultados dos minerais com os valores recomendados pela Organizacao Mundial da Saude, conclui-se que os metais presentes nos chas das plantas poderiam contribuir na complementacao das dietas alimentares das pessoas que as utilizam.