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Resumo Introdução: Os determinantes sociais interferem no processo saúde-doença de população ribeirinha, associados ao isolamento territorial, acesso restrito de bens e serviços de saúde. Objetivo: Identificar fatores associados às condições de saúde de crianças e adolescentes e suas mães, de duas comunidades ribeirinhas no rio Madeira, Amazonas, Brasil. Método: Estudo transversal, realizado em abril e agosto de 2017 em duas comunidades ribeirinhas amazônica, com mães, crianças e adolescentes até 19 anos. Foi avaliada as condições sociodemográficas, características maternas, de saúde, das crianças e adolescentes. Foi realizada análise de regressão de Poisson por meio do Stata 13. Resultados: Das 94 mães participantes, 56,4% declararam condições de saúde de seus filhos como regulares a ruins. A condição regular e ruim de saúde de crianças e adolescentes foi associada ao local de moradia, número de eletrodomésticos, consumo diário de salgadinhos, doces e suco artificial, ter doença crônica e ter histórico de internação hospitalar uma vez na vida (p

The effects of methylmercury (MeHg) on exposed populations are a public health problem. In contrast to widely studied neurological damage, few cardiovascular changes have been described. Our group evaluated the cardiotoxicity of a cumulative dose of 70 mg.kg−1 fractioned over a 14-day exposure period in mice (MeHg70 group). The effects of MeHg on proteins relevant to cardiac mitochondrial function were also investigated. The results obtained showed a reduction in oxygen consumption in the two settings. In cardiac tissue samples in oxygraphy studies, this reduction was related to a lower efficiency of complexes II and V, which belong to the oxidative phosphorylation system. In vivo, mice in the MeHg70 group presented lower oxygen consumption and running tolerance, as shown by ergometric analyses. Cardiac stress was evident in the MeHg70 group, as indicated by a marked increase in the level of the mRNA encoding atrial natriuretic peptide. Electrocardiogram studies revealed a lower heart rate at rest in the animals from the MeHg70 group, as well as prolonged left ventricular depolarisation and repolarisation. Through echocardiographic analysis, reductions in the left ventricular ejection fraction and left ventricular wall thickness of approximately 10% and 20%, respectively, were detected. These results indicate that the oral intake of MeHg can decrease cardiac function and oxidative metabolism. This finding highlights the importance of monitoring MeHg levels in humans and animals in contaminated areas, as well as periodically carrying out cardiac function tests.

Mercury (Hg) is a chemical element that poses risks to human health due to its high toxicity and environmental persistence. We determined the total Hg (THg) and methyl Hg (MeHg) concentrations in hair samples from residents of the Demarcação District (Porto Velho, Rondônia) in the Brazilian Amazon, as well as in water and fish samples, to evaluate factors influencing human exposure. The average THg concentration in human hair was 7.86 ± 6.78 mg kg−1 and it was significantly higher in men, with an increasing trend related to age. There was no significant difference between female age groups. Human exposure to Hg through water was negligible compared to fish consumption. The average weekly intake estimates in the community varied between 1.54 and 4.62 μg kg−1, substantially higher than the recommended limit. The fish species with the highest amounts safe for daily consumption were herbivores and detritivores. Our results contribute to an understanding of how exposure to Hg affects the health of riverside populations and provide insights for new research to develop methods to mitigate such exposure and thus improve the quality of life of Amazonian people.

This study presents a 35-year record of total mercury (Hg) concentrations in the detritivore fish Prochilodus nigricans (Curimatã) and the carnivore Cichla pleiozona (Tucunaré), two of the most widely distributed, ecologically important and consumed fish species in the upper Madeira River Basin in the Western Brazilian Amazon. Fish samples from the major Madeira River and marginal lakes and tributaries were compared. Irrespective of site, Hg concentrations were higher in the carnivore fish compared to the detritivore. Hg concentrations increased 5-fold in C. pleiozona in the past three decades, whereas they remained relatively constant in P. nigricans when analyzing the entire 35-year period. When analyzed separately, fish in the main river and marginal lake and tributaries presented the same pattern of Hg variation, with a significant increase in Hg concentrations in the carnivore and in the detritivore in marginal lakes and tributaries but not in the main river. This was in line with the increase in methyl-Hg production in tributaries, mostly associated with deforestation in the past decade in the basin. Although an increase in direct emissions from artisanal gold mining also occurred in the past decade, this caused virtually no impact on fish Hg concentrations, suggesting atmospheric emission and deposition in forests and further export to water systems as an intermediate link with fish Hg concentrations.

O objetivo deste trabalho foi avaliar a utilização de efluente doméstico tratado para o crescimento de Scenesdesmus sp e Chlorella sp e o potencial dessas microalgas para a remoção de nutrientes. Os efluentes foram coletados em maio (experimento com Scendesmus sp) e setembro de 2016 (experimento com Chlorella sp). Diluiu-se o efluente com água destilada em concentrações de 25% e 50%, e houve um tratamento sem diluição. No controle utilizou-se meio ASM-1. O experimento durou 15 dias, e a cada três dias foram realizadas análises de nutrientes, densidade de microlagas, pH e temperatura. O maior aumento na densidade foi obtido no T100%. Houve a redução dos teores dos nutrientes para as duas microalgas testadas. No T25%, para a Scenesdesmus sp a redução foi de 81,3% para amônia e 44% para o fósforo. Já para a Chlorella sp a remoção de amônia foi de 70% e a de fósforo de 60%. O efluente foi eficiente para o crescimento das cepas e paralelamente reduziu as concentrações de nutrientes.

From 1980 to 2020, the Paciá River Drainage Basin (BHRP – Bacia Hidrográfica do Rio Paciá), located in the Southern Amazon agricultural frontier, underwent an accelerated process of change in human land use and occupation. This study aimed to identify and analyze deforestation patterns, relating them to landscape metrics and the stages of expansion of the agricultural frontier. The methodology was based on the following phases: 1) organizational structure of GIS (Geographic Information System) modeling; 2) mapping and classification of deforestation patterns; 3) mapping of the expansion stages of the agricultural frontier. Diffuse and geometric patterns represented 72.5% of the polygons analyzed, corresponding to 15.64% of deforestation. However, linear and consolidated patterns, which referred to 12.5% of the polygons, represented 65.5% of the deforested areas in the BHRP. The spatial arrangements of deforestation polygons are associated with two evolutionary stages of the Amazon agricultural frontier: permanent/consolidated, which is located along the Transamazon highway, and pioneer/diffuse, located along the banks of rural roads and the main course of the Paciá River.

In order to assess the influencing factors of the presence of mercury in a river within the Savanna biome (Cerrado), we surveyed total mercury (THg) in bottom sediment from 50 lakes along 750 km of the Middle Araguaia floodplain. The sampling sites included non-urban and urban surroundings over three distinct geomorphologies. We measured water physicochemical parameters at each site and tested statistically if land use nested within the geological formation influenced the THg concentration in bottom sediments and related water parameters. Multivariate results indicate that the interaction between geological groups and land use is statistically significant (p < 0.05). Nested ANOVA and Tukey HSD tests confirmed that the geological formation with its nested land use influences the THg, pH, DO, conductivity, and TDS (p < 0.05). THg was significantly lower in Quaternary terrains (p < 0.05) and differed significantly between non-urban and urban areas in Neoproterozoic terrains (p = 0.02). The spatial projections of the THg eigenvector on the main axes with the scoring factors of the Neoproterozoic/Paleoproterozoic terrains, and urban/non-urban, confirmed the spatial correlations. These results indicate that the association of land use and geology could be the main driver of THg in the bottom sediments of lakes from the Middle Araguaia floodplain.

This study evaluates the use of mercury (Hg) concentrations in fish muscle tissue to determine a species’ trophic position (TP) in its environment. A campaign conducted in 2019 along 375 km in the middle Araguaia River basin, Brazil, resulted in 239 organisms from 20 species collected. The highest total mercury (THg) concentrations were found in Pellonacastelnaeana (6.93 µg·g−1, wet weight) and in Triportheus elongatus (3.18 µg·g−1, wet weight), whose TPs were different according to the FishBase database. However, they occupied the same trophic level in this study. The intra-specific comparison showed a difference in Hg concentrations between individuals captured in distinct sites. The study of the biota–sediment accumulation factor (BSAF) showed that spatiality interferes with a species’ TP. Statistical analyses revealed that when we used a predicted species’ TP based on each individual’s size, it explained 72% of the variability in THg concentration across all fish species. Multiple regression analysis confirmed that standard length and FishBase values are positively associated with THg (R2 = 0.943). These results point to Hg as a viable indicator of a fish species’ TP since it reflects regional, biological, and environmental factors, as demonstrated here for the middle Araguaia River.

A população de Lábrea – AM está estimada em 46.069 habitantes, dos quais quase 70% vive em área urbana. A migração da população campo-cidade tem propiciado a expansão indiscriminada do espaço urbano de Lábrea. Por isso, é comum encontrar domicílios em áreas impróprias para instalação de moradias, não só do ponto de vista da fragilidade ambiental, mas também do ponto de vista geotécnico. Assim, o estudo teve o objetivo de realizar o diagnóstico da fragilidade ambiental potencial na área urbana do município de Lábrea. Os procedimentos metodológicos foram organizados em etapas: 1) arquitetura organizacional dos dados no SIG; 2) preparação de base cartográfica e processamento digital de imagem e; 3) determinação das classes de fragilidade potencial, a partir do método de individualização de unidades ecodinâmicas instáveis e estáveis. A cidade de Lábrea apresenta áreas com fragilidade ambiental potencial fraca, média e forte, correspondendo a 33,18%, 7,3% e 51,63% respectivamente. As unidades morfológicas de planície e os vales fluviais mostraram-se mais sensíveis às mudanças do sistema natural. Por outro lado, as unidades de depressão e terraços fluviais apresentaram média e fraca fragilidade ambiental, condições favoráveis ao processo de ampliação planejada da urbanização.

Mercury (Hg) biomagnification in fish food chains is a relevant subject due to the high fish consumption of the Amazonian population and the high toxicity of this metal. In the Amazon, floodplain lake hydrodynamics change considerably along the four seasons of the hydrological cycle (rising water, high water, falling water and low water), which can influence Hg bioaccumulation in fish. The main aim of this study was to evaluate if Hg biomagnification is influenced by seasonality in a floodplain lake (Puruzinho Lake) in the Brazilian Amazon. Additionally, the influence of food chain modeling on measurement of Hg biomagnification was tested. Hg concentrations and stable isotope signatures (carbon and nitrogen) were estimated in four species, Mylossoma duriventre (herbivorous), Prochilodus nigricans (detritivorous), Cichla pleiozona (piscivorous) and Serrasalmus rhombeus (piscivorous). The “trophic magnification slope” (TMS) of the food chain composed by the four species was calculated and compared among the four seasons. There was no significant seasonal variation in TMS among rising water, high water, falling water and low water seasons (p = 0.08), suggesting that Hg biomagnification does not change seasonally. However, there was significant variation in TMS among different food chain models. Lower TMS was observed in a food chain composed of detritivorous and piscivorous fish (0.20) in comparison with a food chain composed of the four species (0.26). The results indicate food chain modeling influences TMS results.

The current study combined chemical data on trace elements and polycyclic aromatic hydrocarbons (PAH) from sediment and used a multibiomarker approach in the catfish Sciades herzbergii to evaluate two different sites in São Marcos Bay, Brazil. Higher diffuse contaminations by trace elements and PAH were detected in the sediment of Porto Grande (PG) harbor than in the Ilha dos Caranguejos (IC) reference area. A multibiomarker was used in catfish to evaluate the bioavailability of PAH in bile and the effects of pollutants in target tissues. The parameters considered were oxidative stress biomarkers (SOD, CAT, GSH, GST and LPO) and histopathological alterations and were compared between two seasons. The biological responses revealed adverse effects on the population, as indicated by the presence of trace elements and PAH as stressors. Principal component analysis (PCA) of the biomarkers corroborated these results and indicated that fish from the PG site during the rainy season in 2019 exhibited many biological effects compared to 2018. Overall, the present study showed that environmental contamination increased over the years and provides information on the contamination of sediments in the São Marcos Bay, Brazil. The results showed that the presence of contaminants was correlated with the health status of the catfish S. herzbergii.

Freshwater invertebrates occupy important roles in ecological processes and are frequently used as indicators of water quality. Their existence, however, is still obscure in many regions of the country, i.e. very few relevant studies have been conducted regarding their presence especially in the Amazon region. Thus, this study aimed to present an inventory of aquatic macroinvertebrates from the marginal region of an Amazonian lake. This study was conducted in a floodplain area, at the Extractivist Reserve of Cuniã Lake (margin of the Madeira River).To sample macrofauna, were collected sediment and aquatic macrophytes near the marginal region in seven sites during low-water season (August 2015) and the high-water season (February 2016). The environmental variables (water temperature (ºC), electric conductivity (μS /cm), pH, and dissolved oxygen (mg/L) were measured at each site and concentrations of organic matter in the sediment were also determined. A total of 28 taxa were recorded. The most significant taxa for the lake were the genera: Campsurus (Ephemeroptera: Polymitarcydae) and Tenagobia (Hemiptera: Corixidae. The lake presents diverse macrofauna, indicating good environmental quality and organic enrichment, which highlights the importance of flood in composition of local macrofauna.

A cohort of 100 exclusively breastfed children was formed to study association between neurodevelopment and Hg exposure [1]. Detailed questionnaires were administered by trained interviewers to the mothers, and measurements of early child development were collected at 6, 36 and 60 months by trained nurses and psychologists using the Gesell Developmental Schedules. The association between prenatal and postnatal organic Hg (methyl-Hg from fish consumption and ethyl-Hg from Thimerosal-containing vaccine) exposures with Gesell scores of the four domains [Adaptive ability, Language development, Motor abilities (gross motor), and Personal-social ability] were studied in preschool children. Keywords: Child development, Fish, Mercury exposure, Hair mercury

The Jaci-Paraná District has an average population of 18.000 inhabitants and is situated at 87 km from the city of Porto Velho, Rondônia, Western Amazon. In this district sanitation is non-existent. Thus, the water abstraction is carried from wells, mainly "amazons" and sewage wastes are thrown in the open, black pits or small streams. This study aimed to evaluate the quality of groundwater resources through the following parameters: electrical conductivity, apparent color, pH, ionic constituents, such as fluoride, chloride, nitrite, bromide, nitrate, phosphate, sulfate, lithium, sodium, ammonium, potassium, calcium and magnesium, and microbiological analysis of fecal coliforms and total coliforms. The collection of samples was conducted in the months of December/2011 and May/2012. All 82 samples were contaminated by total coliforms and 42.3% of water samples had nitrate levels above the maximum value allowed by the MS Ordinance 2914/2011 for potability of water, which is 10 mg L-1.

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.

ABSTRACT The studies on metals in Madeira River’s principal flow show high variability of Co, Cr, Cu, Fe, Ni, Pb and Zn concentrations. However, the transfer of these metals from the main river channel, whose physical and chemical characteristics differ from those of lakes, has not been fully characterized. The objective of this study was to discuss how the transfer of Madeira River’s metals changes the spatial dynamics of these metals in sediments of the Puruzinho Lake (AM). The principal component analysis pointed to differences in the order of the data, creating two distribution zones of metals. The average concentrations of Co, Cu, Cr, Mn and Fe are higher in the area under the influence of the suspended solids coming from the Madeira River. The zoning of metals in lakes is structured by the forces acting across the river’s course at the same time as plains flood and generates ecotones.

This study was conducted in the Western Amazon, in an area located on the campus of the Federal University of Rondônia in Porto Velho, Rondônia. Were analyzed in soil samples of mercury (Hg) and organic matter (OM) concentrations in a stretch of open rain forest. The average Hg concentration was 150 ± 28g.kg-1, whereas the concentration of OM was approximately 21.87 ± 5.87%. The method used to obtain the spatial distribution patterns of Hg and OM concentrations was the indicator kriging (KI), which showed that the occurrence of Hg distribution patterns obeys controlled by geological factors in the region, rich in granitic rocks, and the morphological parameters such as soil texture clay, which has a high degree of adsorption of heavy metals. The distribution of OM in turn, is related to the large amount of litter accumulated on the soil surface, together with the presence of microorganisms, fungi and small invertebrates. The conversion of this material into humus favors vegetation growth and its high concentration influences the amount of heavy metals in soil. The model set variography showed spatial dependence among the mercury levels in the soil of the area studied in relation to the use of the bygone area. The OM and Hg determination was approximately of 0.173 and significant (p = 0.0001). Keywords: Geostatistics; Indicative Kriging; Organic Matter; Western Amazonia.

The groundwater of the Parecis Aquifer (PA) represents the only source of public drinking water supply in the VilhenaCity, RO. In this way, an evaluation of water quality determined by physical, chemical and microbiological analyzes can provide data to understand the consumed water conditions. In the present study, two groundwater collections were performed in 12 wells distributed around the city: the first one in the dry season, in August 2013; and the second one in rainy season, in December of 2013. The parameters analyzed were the ionic constituents (F-, Cl-, NO2-,Br-,NO3-,PO4-3,SO4-2,Na+,NH4+, K+,Ca2+ eMg2+) that were quantified by ion chromatography, while for microbiological analysis, the method utilized was the chromogenic media used in membranes filtration. The parameters pH and turbidity were measured using a portable pH meter, and a portable turbidimeter. The results showed values below the limits established by CONAMA Resolution396/2008 and the MS Directive 2914/2011for turbidity and all of ionic constituents, except for nitrate (6 wells)and ammonium (1 well), as well as presence of acid pH. The rainy season presented more contamination by Escherichia coli and total coliforms than the dry period, and it can be associated with bad conditions of wells, besides it is an unconfined aquifer, it has been facilitating the flow of possible contaminants. The results shown the importance of a constant monitoring in the water quality in communities that have been using alternative sources, avoiding problems related to human health.

The aim of this study was to evaluate the quality of fish meat in relation to inorganic contaminants (Zn, Pb, Cu, Cr, Ni and Hg), following the Brazilian Health Surveillance Agency (ANVISA) standards in five Amazonian fish exposed to untreated urban sewage. Trace metal concentrations were evaluated in the muscle tissues of Schizodon fasciatus (herbivorous), Potamorhina latior (detritivorous), Triportheus angulatus (omnivorous), Plagioscion squamosissimus (carnivorous) and Rhaphiodon vulpinus (piscivorous), sampled upstream and downstream of Santo Antônio’s Hydroelectric Dam, Madeira River (Porto Velho City, Brazil). An acid chemical digestion was used to extract trace metals from the tissues, and atomic absorption spectrometry methods were used to quantify the trace metal concentrations. Fish samples showed values above allowed limits for Cr (0.10 mg.kg-1 ), except in Plagioscion squamosissimus (0.09 mg.kg-1 ). Potamorhina latior specimens sampled downstream showed higher values for Cr (p

The study was conducted in Puruzinho lake (Humaitá, AM) considering seasonal periods of rainy and dry in way to elucidate the flood pulse importance in the deposition, remobilization and distributions of mercury and organic matter in bottom sediments in the Madeira River Basin (Brazilian Amazon). Bottom sediments and soils samples were analyzed for total mercury and organic matter. Mercury concentrations obtained in bottom sediment were 32.20-146.40 ng g-1 and organic matter values were 3.5 - 18.0%. The main region for accumulation of mercury and organic matter was in the central and deepest lake area In the rainy season there was a greater distribution of Hg and organic matter, mainly controlled by means of income of the Madeira river water during flooding, while the predominant process in the dry season was the remobilization of total Hg due to the resuspension of bottom sediments.

O objetivo deste estudo foi estimar a prevalência de hipertensão em adultos residentes nas comunidades ribeirinhas do rio Madeira, previamente à operação da Usina Hidrelétrica Santo Antônio. Estudo transversal da prevalência de hipertensão arterial realizado com 841 adultos. Informações sobre condições sociodemográficas, morbidade referida, hábitos de vida, consumo de peixe e dados antropométricos foram avaliados. O método de regressão logística foi utilizado para estimar a odds ratio e seus respectivos intervalos de confiança. Entre os ribeirinhos, 26% (IC95%: 23%29%) dos adultos apresentaram hipertensão: 29% entre os homens (IC95%: 24%-33%) e 23% entre as mulheres (IC95%: 19%-27%). Nos homens, os fatores associados à hipertensão foram idade, IMC, glicemia e local de residência. Entre as mulheres, os fatores preditivos foram idade, triglicerídeos e glicemia. Os resultados deste estudo podem contribuir com a formulação de estratégias de monitoramento para prevenção de eventos cardiovasculares por parte dos órgãos de saúde estadual e municipal.

Os sistemas agroflorestais (SAF’s) além de gerar renda e alimentos, apresentam potencial para atenuar a liberação de carbono do solo, causada pela mudança no uso da terra na Amazônia. Nosso objetivo foi avaliar a variabilidade de atributos físico-químicos do solo e dos estoques de carbono (EC) orgânico do solo em SAF’s do assentamento rural Umari, sul do Amazonas. Foram utilizados quatro métodos: i) preparação de base cartográfica e processamento digital de imagem, ii) construção parcela fixa e monólito de solo, iii) análise física e química de solo e iv) análise estatística e geoestatística. No SAF19 e SQF15 observou-se os maiores EC (21,02 Mg C. ha-1 e 18.86 Mg C. ha-1) na camada de 0 -10cm de profundidade no período chuvoso e os menores EC (2,58 Mg C. ha-¹) foram registrados na agrícola itinerante. Os SAF’s com maior tempo de adoção promoveram o aumento do EC e a recuperação de atributos químicos do solo do PA-Umari.

Over the last 20 years several projects carried on the Madeira River basin in the Amazon produced a great amount data on total Hg concentration in different fish species. In this paper we discuss temporal trends in Hg contamination and its relation to body weight in some of those fishes, showing that even within similar groups, such as carnivorous and non-migratory fish, the interspecies variability in Hg accumulation is considerable.Vários estudos têm sido desenvolvidos nos últimos 20 anos na bacia do Rio Madeira (Amazônia) com o objetivo de diagnosticar a presença de mercúrio em peixes e compreender o ciclo deste elemento no meio ambiente tropical. Neste artigo são discutidas tendências temporais na concentração de Hg e sua relação com a massa corporal de algumas espécies de peixes com diferentes hábitos alimentares, coletadas no Rio Madeira e no reservatório da hidroelétrica de Samuel, no Rio Jamari, Estado de Rondônia. Foi avaliada uma amostragem de peixes de 14 anos (1987 - 2000) com 86 espécies e um total de 1100 espécimes.

The extraction of gold in the Amazon, since 1970, has grown fast from a politic that was resulted in the creation of gold extraction reserves in this region. In the Madeira River the gold exploration is noticeable because of the deposition of mercury in the environment. This metal is toxic and it resists to degradation process, transforming itself chemically, till it gets to its organic form, known as very toxic. Its extensive usage in the gold recover has caused impacts to the environment and consequently to the population, according to studies already done. This study has as its goal to value the pollution by Hg in soils and the variation according to soil fractions. The soils were collected by profiles in 10 areas in the Madeira River. The determination of organic matter was done, according (BRASIL, 1999).To Hg determination it was selected the fraction

A expansão dos sistemas agropecuários tem transformado o espaço agrário sul amazônico, em especial o meio rural do município de Lábrea – AM. Neste ambiente as grandes manchas de solo foram classificadas em mapeamentos exploratórios como de baixíssima fertilidade. Mas, em áreas menores pode haver solos férteis, originários de processos naturais ou antropogênicos. Neste contexto o objetivo deste estudo foi realizar o levantamento das principais classes de solo e suas características geoquímicas em diferentes sistemas de uso da terra na microbacia hidrográfica do rio Paciá – Amazonas. Os procedimentos metodológicos foram organizados em etapas: 1) preparação da base cartográfica e processamento digital de imagens; 2) observação do uso e cobertura da terra e amostragem do solo; 3) procedimentos laboratoriais; 4) análise espacial e não-espacial. Os resultados indicam que os solos são ácidos, com pH entre 3,9 a 5,1, exceto na área de várzea onde a acidez é moderada. Na área de estudo, identificou-se a ocorrência de cinco classes de solo: Latossolo, Argissolo, Gleissolo, Neossolo e Plintossolo.

Top marine predators present high mercury concentrations in their tissues as consequence of biomagnification of the most toxic form of this metal, methylmercury (MeHg). The present study concerns mercury accumulation by Guiana dolphins (Sotalia guianensis), highlighting the selenium-mediated methylmercury detoxification process. Liver samples from 19 dolphins incidentally captured within Guanabara Bay (Rio de Janeiro State, Brazil) from 1994 to 2006 were analyzed for total mercury (THg), methylmercury (MeHg), total organic mercury (TOrgHg) and selenium (Se). X-ray microanalyses were also performed. The specimens, including from fetuses to 30-year-old dolphins, comprising 8 females and 11 males, presented high THg (0.53-132 µg/g wet wt.) and Se concentrations (0.17-74.8 µg/g wet wt.). Correlations between THg, MeHg, TOrgHg and Se were verified with age (p

O presente estudo teve o objetivo de avaliar as mudanças no uso da terra e seus efeitos na qualidade da água na microbacia do rio Preto - RO. Esta foi escolhida por ser uma área de projetos de assentamento para colonos, o que viabilizou o processo de ocupação do estado de Rondônia. A metodologia foi dividida em três etapas: preparação da base cartográfica e processamento digital de imagens de satélite, atividade de campo com aplicação de formulário sobre o uso da terra e coleta de amostras de água, e integração das informações através de Sistema de Informação Geográfica - SIG. Na área sobre influência da agricultura cafeeira a concentração de OD foi 1,61 mg/l, a temperatura de 27,5º C, pH entre 4,4 e 4,7 e média de condutividade 15,8 S25/cm. Foi constatado mudança no uso da terra, que está relacionada ao desenvolvimento econômico recente e histórico de colonização. Como consequência trechos de rios apresentam padrão de qualidade de água inferior ao recomendado pela legislação CONAMA Nº 357/2005.

Objetivo : Estudar a prevalência de zumbido, verificando se há associação entre a queixa desse sintoma e o teor de mercúrio e mensurar seu impacto na qualidade de vida. Métodos : Estudo seccional em toda a população do Lago do Puruzinho, localizada na margem esquerda do Rio Madeira, cidade de Humaitá, Estado do Amazonas, Brasil. Todos os residentes maiores de 18 anos, de ambos os gêneros, foram submetidos à anamnese, avaliação otorrinolaringológica e exame audiológico. Os indivíduos que apresentaram queixa de zumbido responderam à versão traduzida do questionário Tinnitus Handicap Inventory (THI). Também foram pesquisados os teores de mercúrio total no cabelo desses indivíduos. Resultados: Para análise dos resultados sobre a queixa de zumbido, os sujeitos foram divididos em dois grupos quanto à presença ou não de zumbido. O Grupo 1 foi composto por indivíduos que apresentaram queixa de zumbido e o Grupo 2, por indivíduos sem zumbido. Foi observado que 40% dos indivíduos apresentaram escores do THI compatíveis com handicap leve. A análise da associação da presença de zumbido com os teores de mercúrio total no cabelo mostrou que ambos os grupos apresentaram níveis elevados de mercúrio, porém não ocorreram diferenças entre os grupos. Conclusão : Um quarto dos ribeirinhos apresentou queixa de zumbido e exposição significativa ao mercúrio, mas não houve associação entre o zumbido e os níveis elevados de mercúrio.

ABSTRACT Objective: to verify mercury exposure prevalence and identify its possible associated factors in two riverside communities in the Madeira River basin of the Western Brazilian Amazon. Method: a cross-sectional study comprising 95 children and adolescents. Age cycle, school attendance, Bolsa Família, number of siblings, meals, fish consumption, height by age were measured. Binary logistic regression was used to verify relationships between mercury exposure and its possible associated factors. Results: the general prevalence of mercury exposure was 46.3%; children, 35.4%; and adolescents, 57.4%. Associated factors were fish consumption (aOR=1.84; 95%CI 1.56-2.16), age cycle (aOR=2.50; 95%CI 1.09-5.7), parasites (aOR=1.22; 95%CI 1.02-2.71), and short stature (aOR=1.32; 95%CI 1.05-2.02). Conclusion: mercury exposure prevalence in riverside children and adolescents was considered worrying, with association with fish consumption, adolescence, parasites, and short stature.