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The Brazilian Amazon is heavily impacted by mining activities, especially by gold and cassiterite mining. Pb is a contaminant released during cassiterite extraction, and it stands out for its high toxicity. The present study aimed to evaluate the effect of flood pulse on Pb dynamics in four fish species with different feeding habits (Cichlapleiozona: carnivorous, Mylossomaduriventre: herbivorous, Prochilodus nigricans: detritivorous, and Serrasalmus rhombeus: piscivorous) over four hydrological periods in Puruzinho Lake (Brazilian Amazon), which receives water from the Madeira River. The risk assessment for daily Pb intake through the consumption of these fish by the local riverside population was also carried out. Fish species were sampled during four Amazonian hydrological periods: rising water, high water, falling water, and low water. Pb and stable isotopes (δ

The isotopic signatures of carbon in primary consumer fish species in the Madeira River basin (Western Amazon) follow a pattern, with basal species feeding mainly on C

O objetivo deste trabalho é reunir em revisão narrativa da literatura textos disponíveis sobre os impactos de saúde em comunidades indígenas pela poluição atmosférica de incêndios florestais e queimadas. Foi realizado busca utilizando descritores relacionados à poluição do ar, serviços de saúde indígena e incêndios florestais, totalizando 13 artigos. Foram considerados artigos científicos completos publicados entre 2012 e 2022 nas bases eletrônicas PUBMED e SCOPUS. Observa-se escassez de estudos específicos sobre impactos da poluição atmosférica na saúde, possíveis agravos que acometem os povos indígenas no Brasil e déficit na literatura científica sobre o monitoramento da qualidade do ar em terras indígenas. A poluição do ar é um fator limitante para o desenvolvimento humano, e há deficiência de ações de monitoramento e vigilância em saúde dos povos tradicionais na Amazônia Brasileira. É imprescindível que se elabore estratégias que favoreçam o mapeamento das áreas críticas e o monitoramento da qualidade do ar, proporcionando o conhecimento integrado do modo de vida e do grau de vulnerabilidade a que estão expostos os povos indígenas.

Exposure to mercury (Hg) and pesticides (o.p'DDT, p.p'DDT, o.p'DDE, and p.p'DDE) in the Amazon through eating fish is of concern due to the large participation of this food in the diet of traditional fishing communities. The aim of this study was to evaluate the estimated daily intake (EDI) and the incremental lifetime cancer risk associated with Hg and o.p'DDT, p.p'DDT, o.p'DDE, and p.p'DDE in an Amazonian community. The results showed that for Hg, the EDI from carnivorous and detritivorous fish had the highest values, while for pesticides, the EDI from detritivorous fish intake had the highest value. The incremental lifetime cancer risk was below the permitted limit. A recommendation for controlling the high risk of exposure includes the reduction of detritivorous fish ingestion and/or replacement with herbivorous fish, which had lower EDI. We highlight the importance of investigating the human dietary patterns when estimating risk of exposure to Hg and pesticides.

The Machado River is the main tributary of the Madeira River in the state of Rondônia, a region that has been impacted by deforestation, livestock, urban development, alluvial gold mining and urban and industrial effluents that likely contribute to the introduction of mercury (Hg) in the aquatic system. We aimed to determine the concentrations of total Hg (THg) in muscle and liver of Plagioscion squamosissimus, a main fishing resource in the region. Fish were sampled for two years at five sites, along a 90-km stretch of the middle Machado River. THg concentrations were analyzed in 64 muscle and 54 liver samples by cold vapor atomic absorption spectrophotometry (FIMS-400). THg levels were related with fish size and sex and with periods of the hydrological cycle. THg concentrations in both organs were positively and significantly related with fish body size. There was no significant variation in THg among periods of the hydrological cycle. Mean THg concentrations in muscle (1.09 ± 0.72 mg kg-1) and liver (1.28 ± 1.23 mg kg-1) were higher than the limit established by the WHO. Our results suggest that residual mercury from former alluvial gold extraction and lixiviation of mercury naturally occurring in the soil due to large-scale deforestaion is accumulating in the aquatic food chain in the Machado River. We conclude that it is necessary to monitor the levels of mercury in commercially important fish species in the region.

Metals refer to one of the main and most dangerous groups of water contaminants, so this research aimed to investigate the groundwater of Dois de Abril micro basin creek regarding the presence of metals and the spatial distribution of the elements regarding the underground flow direction. To that end,15 collections were performed in wells in February, March (High Waters – AA) and September 2019 (Low Waters – AB). The samples were analyzed for 14 inorganic chemicals by means of Inductively Coupled Plasma Optical Emission spectroscopy (ICP-OES). And through the Surfer 8.0 software, the flow direction was obtained using the potentiometric surface of the tubular wells registered in the Groundwater Information System - SIAGAS. Wilcoxon and Spearman tests were applied for the discussion of the results. The averages obtained are within the Maximum Allowed Values – MAV by the national human consumption legislation, but some wells presented high values for aluminum, iron, lead and barium, due to geochemistry and geology of the region, low pH values and the use and occupation of the soil. The trend of the underground flow direction of the municipality contributes to the main river that crosses the city. The flow direction and statistical tests applied were sufficient to discuss the results.

In the Amazon, the leaching from soil left unprotected by deforestation increases the entry of iron, among other elements, in aquatic ecosystems, which can cause cyanobacterial blooms. This study aimed to investigate the physiological response of a strain of Microcystis panniformis to iron variation. The strain was isolated from a reservoir located in the Western Amazon and produces microcystin-LR. After a period of iron deprivation, the cultures were submitted to three conditions: control (223 μgFe.L−1), treatment with 23 μgFe.L−1, and absence of iron. At regular intervals for eight days, the cell density, levels of chlorophyll a and microcystins were determined. On the second and fourth day, transcription of genes responsive to iron limitation was quantified. Starting on the fourth day of the experiment, the different iron concentrations affected growth, and on the eighth day in the iron-free condition cell density was 90% lower than in control. Chlorophyll cell quota in 23 μgFe.L−1 and control presented similar values, while without iron the cells became chlorotic as of the fourth day Toxin concentration in cells grow in 0 μgFe.L−1 in relation to the control. Higher transcription levels of the feo and fut genes were observed in the 0 μgFe.L−1 and 23 μgFe.L−1 treatments, indicating that the cells were activating high-affinity capture systems to reestablish an adequate concentration of intracellular iron. The increasing deforestation in the Jamari River Basin (Amazon region), can contribute to the occurrence of toxic cyanobacterial blooms due to the greater entrance of iron in water bodies.

In the Amazon, mercury (Hg) contamination comes from ASGM operations along with soil remobilization processes associated with deforestation. The objective of this study was to evaluate the exposure to methylmercury (MeHg) and total mercury (THg) in 88 samples of skin and blubber tissue obtained from live captured river dolphins (Inia boliviensis, Inia geoffrensis, and Inia spp.) in the Madeira River Basin. THg and MeHg measurements were performed by CV-AAS and GC-AFS, respectively. We also calculated the daily intake rate (DIR) of THg (wet weight) by Inia spp. THg levels in blubber tissue of adult river dolphins (Inia spp.) ranged from 0.015 to 3.804 mg kg-1, while MeHg concentrations in blubber tissue varied from 0.04 to 2.65 mg kg-1 and in skin tissue from 0.09 to 0.66 mg kg-1. There were no significant differences in MeHg concentration in blubber (p = 0.616) and skin (p = 0.498) tissue samples between adult males and females in the different sampling locations. The adult animals showed differences in THg and MeHg concentrations significantly higher than in the calves. The estimate of the DIR of the genus Inia ranged from 1.17 to 12.35 μg kg-1 day-1 (bw), from the consumption of fish species with herbivorous to piscivorous habits, respectively. More biological and ecological data, such as the precise determination of age, mediated length, weight, and diet of river dolphins, are necessary to verify the Hg biomagnification. However, our data indicate that bioaccumulation is an active process in the dolphins of the Madeira River Basin.

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.

The green turtle (Chelonia mydas) is known to present an herbivorous diet as an adult; however, juveniles may have an omnivore habit, and these changes in food preference may affect the uptake and accumulation of pollutants, such as mercury (Hg). In order to better understand the influence of this ontogenetic shift on Hg accumulation, this study evaluates the concentrations of total mercury (THg), methyl mercury (MeHg), and stable isotopes of carbon and nitrogen (δ13C and δ15N) in a group of juveniles of the green turtle. Tissue samples (liver, kidney, muscle, and scutes) were sampled from 47 turtles stranded dead on the coast of Bahia, NE, Brazil, between 2009 and 2013. The turtles analyzed showed a size range of 24.9–62.0 cm and an average of 36.4 ± 7.2 cm of curved carapace length. The scutes showed to be a viable method for Hg monitoring in the green turtles. The concentrations of THg and MeHg decreased with increasing size. The isotope values of δ15N and δ13C did not show a clear relationship with the size, suggesting that the green turtles used in our work would be occupying similar trophic levels, and foraging habitat.

Cr contamination is a growing concern in the Amazon. Along with the rise of cattle farming in the region, tanneries are becoming more common and threatening environmental quality, since the effluents from this activity are rich in Cr. The objective of this study was to evaluate the seasonal and spatial dynamics of Cr in fish with different feeding habits from Puruzinho Lake, located in the Madeira River basin, also determining the daily intake of Cr associated with the consumption of these fish by the population that lives around the lake. Seasonality and feeding habits directly affected Cr dynamics in fish (p 0.0001), with medians of Cr concentration ranging between 0.07 mg kg

Groundwater is heavily exploited for a variety of uses. Depending on their structure, the wells from which water is extracted can act as an entry point/gateway for a variety of microbiological contaminants, which can cause numerous adverse health effects. This study aimed to identify the microorganisms present in the groundwater in the Western Amazonian city of Porto Velho, using a methodology that can be deployed in other city centers. We collected 74 water samples from both dug and drilled wells in March, August and November 2018. Total coliforms were detected in 96% of dug wells and 74% of drilled wells. Thermotolerant coliforms were found in 90% of dug wells and 61% of drilled wells. Biochemical identification indicated 15 genera of bacteria. The genera Escherichia, Enterobacter, Cronobacter and Citrobacter had the highest prevalence. The genera Pseudomonas and Enterococcus were also detected. Thermotolerant coliforms showed higher values when the water flow was higher. Our results indicate high fecal contamination and higher susceptibility to contaminants in shallow wells compared to deep wells. These findings reflect the precariousness of WASH (water, sanitation and hygiene) services and the importance of effective actions to combat groundwater degradation, improve the quality of the environment, and protect public health.

The aim of this study was to evaluate the physical, chemical and microbiological groundwater parameters as well as the mapping of groundwater flow in an urban area of Presidente Médici county in Rondônia State, Southern Amazon. The water samples were collected in 11 wells in April and June of 2017, which corresponds to the dry season in the studied region. Groundwater was acidic, with a large range of nutrients concentration, low turbidity and presence of fecal coliforms in most sampled wells. The parameters that were in disagreement with Consolidation Ordinance No 05/2017/MS and CONAMA no 396/08 Resolution, were pH, turbidity, total coliforms, Escherichia coli, and nitrate. Regarding the microbiological parameter, most of the sampling sites were in disagreement with the established by the legislation that it recommends to be absent in 100mL, when it is destined for human consumption. Densities found were higher than 112,000UFC/100mL for total coliforms and higher than 56,000UFC/100mL for Escherichia coli. The pH ranged from 4.1 to 6.4, and the turbidity showed a maximum value of 6.7 uT. The nitrate concentrations were above the established level (10 mg.L-1) in April in 72.7%, and in June 50% of the wells, with a maximum of 48.5 mg.L-1. The study of the direction of the underground flow demonstrated the predominance of the flow towards the nearest river, as well as potential contributors of microbiological influences. The results indicate contamination of the groundwater by domestic sewage, being proved by the presence of coliforms and nitrate, being the water unfit for human consumption without adequate treatment.

Total mercury (T-Hg) was determined in fish and wild animal meat consumed in indigenous villages in the Brazilian Amazon region, where there is no history of gold mining. The analyses were performed in an atomic absorption spectrophotometer by generation of cold vapour. Regardless of the dietary habit, 42.0% of the fish had levels of T-Hg higher than the values considered as safe for human health by the World Health Organisation. Exposure to mercury in the villages was higher due to the consumption of fish compared to the consumption of meat of wild animals. Carnivorous species showed a higher concentration of T-Hg, both in fish and in wild animals. It is preferred to consume meat from fish and non-predatory wild animals, which can reduce the risk of diseases resulting from high concentrations of mercury in the body of the studied indigenous people.

In the Amazon rainforest, methylmercury (MeHg) is easily biomagnified and bio-accumulated in the aquatic food chain. This unique biome has been studied for occupational and environmental issues related to human health and contamination through fish consumption; however, wildlife studies have not yet addressed fish-eating birds. Different species of birds categorized by foraging strategies and life-stages were studied in the Madeira River Basin (Western Amazon rainforest). Feather and tissue (muscle, liver, kidneys, lungs, heart, brain, and blood) samples were collected opportunistically from six bird species feeding on fish and aquatic fauna and a scavenger (a saprophagous species) during the low-water season (July 2017). All collected samples were analyzed for total Hg (THg); methyl-Hg (MeHg) was determined only in feathers. The mean THg concentrations in feathers (dw) were as follows: Ardea cocoi (4.05 μg g−1, n = 51) > Egretta thulla (3.94 μg g−1, n = 5) > Ardea alba (3.80 μg g−1, n = 61) > Anhinga anhinga (3.69 μg g−1, n = 8) > Nannopterum brasilianus (3.07 μg g−1, n = 10). The scavenger Coragyps atratus showed mean THg in feathers (9.93 μg g−1, n = 30) to be significantly higher than in fish-eating birds. Across species, THg levels in feathers correlated significantly with THgmuscle (p = 0.022) and THgbrain (p = 0.002). THg concentrations varied in tissues (feather > liver > kidneys > lungs > heart > muscle > blood > brain). The Hgbrain:Hgfeather, Hgbrain:Hgmuscle, and Hgbrain:Hgblood ratios were 0.031, 0.503 and 0.516, respectively. The mean [MeHg:THg] ratio in feathers from aquatic birds varied between species from 14 to 74% with a mean of 38%. Scavenger birds that forage in the terrestrial Amazonian environments concentrate more THg than species that forage in the aquatic environment. None of the aquatic species showed THg concentration in internal organs that were above threshold for risk of Hg toxicity; additionally, they are not listed in the categories of threat by the International Union for Conservation of Nature (IUCN).

The concentration of chlorine in water declines as it reacts with various substances, causing decay of the residual free chlorine until its total consumption. In light of the typical characteristics of the water from protected dug wells and tube wells, this study aimed to evaluate the decay kinetics of free chlorine in the water of alternative individual supply (AIS) solutions used in the city of Porto Velho in the Brazilian Amazon region. The free chlorine decay constant in the water was evaluated by “bottle tests,” applying a first-order model. According to the results, the type of well and initial chlorine concentration significantly influences the free chlorine decay speed. The water samples from the tubular wells had lower chlorine demand levels, attributed to their better water quality. The simulation of the residual chlorine decay in the different supply sources is an important tool to support safe disinfection processes.

Groundwater quality can be affected by many factors. The objective of this study was to assess the quality of groundwater and map the flow direction, to identify possible sources of contamination in the districts of Nova Londrina and Nova Colina (Ji-Paraná, Rondônia). Water samples were collected in September 2015 and February 2016 in 20 wells in Nova Londrina and in December 2016 and April 2017 in 15 wells in Nova Colina. The turbidity, pH and electrical conductivity (EC) were measured in loco. The microbiological parameters were determined by the membrane filtration method in a chromogenic medium, and the total dissolved solids (TDS) were measured by the gravimetric method. The nutrients ammonia, nitrite, nitrate, dissolved phosphorus and total phosphorus were ascertained by the spectrophotometric method and the underground flow was obtained by applying the Surfer 8.0 software. Through principal component analysis (PCA) it was possible to detect that the TDS, total coliforms, pH and EC had important contributions to formation of the groundwater axes in Nova Londrina, while the variables EC, nitrate and well and cesspit depths contributed in Nova Colina. The groundwater flow did not differ among the months studied, and was mainly in the northwest-southeast direction in Nova Londrina and from the southeast to other regions in Nova Colina.

Este trabalho teve por objetivo avaliar a qualidade da água subterrânea do aquífero livre na microbacia do igarapé Nazaré (Ji-Paraná-RO), por meio de análises físico-químicas e microbiológicas. Foram realizadas 4 coletas de amostras de água em 15 poços rasos nos meses de (março, junho, setembro e dezembro de 2019). Os parâmetros condutividade elétrica, temperatura e o pH foram determinadas in loco por meio de sonda multiparâmetros. A turbidez e os sólidos totais dissolvidos foram determinados no laboratório com sondas especificas. O oxigênio dissolvido foi determinado pelo método titulométrico, a alcalinidade total foi obtida por titulação potenciométrica. As análises dos nutrientes foram realizadas por métodos espectrofotométricos, e as análises microbiológicas realizadas conforme o método de membrana filtrante em meio cromogênico. De acordo com os Valores Máximos Permitidos estabelecidos pela Portaria de Consolidação n° 5/2017 do Ministério da Saúde e com a Resolução do Conselho Nacional do Meio Ambiente CONAMA n° 396/2008, estiveram em desconformidade com tais legislações os coliformes totais, Escherichia coli, pH, turbidez e o nitrato. A análise de componentes principais não evidenciou diferença entre os períodos avaliados. Os resultados indicaram que a água dos poços encontra-se fora do padrão de potabilidade permitido para o consumo, podendo apresentar riscos à saúde humana.

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.

The present study aims to understand how ecological and biological factors affect the Hg levels in stingrays occurring in the Northeastern Brazilian coast. Total mercury (Hg), methylmercury (MeHg) and stable isotope (δ13C and δ15N) analyses were performed in five species. Hypanus americanus and Gymnura micrura showed the highest total Hg concentrations (300 and 176 ng.g−1, respectively). Hypanus guttatus exhibited a significant correlation between total Hg and size. Both species of the genus Hypanus presented the highest percentage of MeHg, around 100%, whereas the other species showed median percentages below 50%. The δ13C and δ15N signatures suggest that all studied species present the same foraging habitat but different trophic positions. Trophic position and animal size were the main factors influencing total Hg and MeHg concentrations in batoid species. The genus Hypanus, present in the Brazilian fish markets, showed concentrations above the accepted limits for human consumption.

The simple view of the classical phytoplankton–zooplankton–fish food chain (CFC) has been replaced by a more complex framework, integrating microbial compartments (microbial food web, MFW). Few studies considered all components of the pelagic MFW in freshwaters and mostly are from temperate regions. We investigated carbon partitioning in the CFC and the MFW in an Amazonian floodplain system and analyzed the strength of interactions among components through structure equation modeling. We hypothesized that (i) MFW contributes highly to total plankton biomass throughout the year; and (ii) all plankton communities increase in biomass during low water, increasing the role of trophic interactions. We collected 30 subsurface samples (nutrients and plankton communities). MFW predominated over CFC in carbon biomass, and plankton components and their interactions changed according to the contrasting water level. Because phosphorus can be a potentially limiting resource for strict primary producers, higher biomass and a more complex MFW occurred during low water. We concluded that hydrology is a key factor shaping biotic interactions during low-water periods, and that MFW plays a key role in floodplain lakes, being potential mixotrophy an important strategy for phytoplankton.

Damming rivers to generate electricity creates a lentic environment that favors methylmercury (MeHg) formation. Reservoirs in the Amazon are critical environments for MeHg formation, considering its old soils and the use of Hg in gold mining in the region. The objective of this study was to evaluate MeHg accumulation in three environmental compartments (aquatic macrophytes, suspended particulate matter (SPM) and sediment) of the Samuel reservoir (Western Amazon, Brazil), during the low water, ebb and high water hydrological periods, characterizing the dry season, the end of the rainy season and the rainy season, respectively. MeHg concentrations were determined through GC-AFS. The aquatic macrophytes presented higher %MeHg in their roots (up to 12%) compared to their other tissues. This ratio was 1.7 and 5.9 times higher than those observed for SPM and the sediment, but MeHg concentrations were the lowest (0.5–4.5 ng g−1) among the three environmental compartments. Contrary, the highest MeHg concentration was observed in SPM (104 ng g−1) during the low water period. The MeHg concentration in the sediment profile decreased with increasing depth (0.93–0.48 ng g−1) and with decreasing organic matter lability (increasing C:N ratio). In the SPM, on the other hand, MeHg concentration showed a positive association with increasing C:N ratio. We conclude that MeHg dynamics in the SPM are associated with the hydrological periods, with peaks during the low water period. The organic matter lability of the sediments is more limiting to the production of MeHg than the total Hg concentrations.

The energy transfer in the aquatic food chain is an important way for mercury (Hg) to enter other trophic levels. The objective of this work was to evaluate the Hg concentrations in plankton upstream and downstream of the Samuel Hydroelectric Reservoir, Rondonia, Brazil. Phytoplankton and zooplankton samples were collected with 20-μm and 68-μm nylon nets. An aliquot was removed for taxonomic analysis and another for total mercury determination, performed by cold vapor atomic absorption spectroscopy. Water physical-chemical parameters were also measured. The Hg concentrations in total plankton (phytoplankton and zooplankton samples) obtained at the three sampling upstream stations showed the same behavior, with the highest values registered in June 2005 (232 μg kg-1, 118 μg kg-1, 128 μg kg-1). The lowest values at stations J1 and M1 were recorded in November 2005 (4 μg kg-1 and 22 μg kg-1, respectively), while the lowest values at stations M4 and M8 were recorded in October 2005 (22 μg kg-1 and 5 μg kg-1, respectively). The Hg results found in the plankton in this study corroborate the results of other recent studies in the same region. The statistical analyses revealed that Hg concentrations in plankton do not explain the distribution of these organisms at the four sampling stations of Samuel Reservoir. Graphical Abstract.

This study was to evaluate the exposure to methylmercury (HgMe) and the potential health risk of Tupari Indians through the consumption of their main foods. Were collection of samples of plant foods and muscle tissue from different species of fish and wild animals consumed in three villages of the Rio Branco Indigenous Land in Rondonia, in the Brazilian Amazon. The HgMe was measured in an atomic fluorescence spectrophotometer with gas chromatography. The statistical treatment of the data was performed by software R. Of the six different plant species, only sweet potato (Ipomoea batatas) had mean concentrations of HgMe above the limit of detection of the analytical technique for the three villages. There was a significant difference in the levels of HgMe between the species of wild animals and fish belonging to the same alimentary habit. Carnivores presented higher levels of HgMe than those obtained for non-predators, both for fish and for wild animals. The results of the assessment of the potential risk to indigenous health indicated a total HgMe of the weekly ingestion rate (WIR) of between 8.4 and 15.0 μg / kg of body weight for the villages evaluated, extrapolating all reference doses ( RfD) regarding for the Provisional Tolerable Weekly Intake (PTWI). The risk quotients (RQ) varied from 5.3 to 21.4, considerably exceeding the limit (RQ ≤ 1), which allows to consider the impossibility of toxic effects of HgMe. The fishes accounted for the highest percentage of WIR of HgMe for all villages, with an emphasis on predatory species. Considering the nutritional value of fish meat, it is suggested the continuity of the consumption of this meat in the villages with preference for non-carnivores.

Scientific studies suggest that eating habits of traditional communities all over the world have been suffering changes as a result of gradual replacement of regional products with imported ones and also because of the increase of consumption of carbohydrates and trans fats. The nutritional state of populations, as riverine people in the Amazon region, has been widely affected by factors as changes in the eating and epidemiologic patterns. This study aims at the identification of the perception of dwellers of a riverine community the Brazilian Amazon region on their eating habits, their health and on the changes caused by development. This is a qualitative study, in which we used ethnographic semi structured interviews as a tool to collect data, conducted through a semi structured script, and applied to 16 dwellers/heads of families, in which 11 are men and 5 are women. The interviews were recorded in audio, full text transcribed and analyzed, and resulted in a descriptive system of categories and subcategories. As a result, we identified an increase of purchase capacity, greater participation in the market economy, lack of effective and continuous actions by the administrators of basic health services in the city. These joint factors contribute to the process of nutritional transition that is occurring in the community, as well as to the increase of health vulnerability of the dwellers.

Background The Madeira River (Amazon Basin) has been impacted by activities related to artisanal and small-scale gold mining (ASGM), deforestation and burning (for timber, agriculture, and hydroelectric dam projects). All these activities contribute to environmental mercury (Hg) release and cycling into the Amazon ecosystem and thus to changing lifestyles. Method We assessed exposure to total and MeHg in two small riverine communities of the Madeira River (Amazon): Lago Puruzinho (LP, n = 26 families) and Sao Sebastiao do Tapuru (SST, n = 31 families). Samples of human hair (n = 137), blood (n = 39), and feces (n = 41) were collected from adults and children (0–15 years of age). Results In women of childbearing age from LP village, the mean blood total-Hg (THg) (45.54 ± 24.76 μg.L−1) and MeHg (10.79 ± 4.36 μg.L−1) concentrations were significantly (p = 0.0024; p Conclusion Women and children excrete THg in feces in comparable concentrations. However, the mean fish consumption rate and blood MeHg are higher in the most remote villagers. Mother`s hair-Hg concentration is a good predictor of children’s hair-Hg.

Wetlands are the largest global source of atmospheric methane (CH4), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain, the largest natural geographic source of CH4 in the tropics, consistently underestimate the atmospheric burden of CH4 determined via remote sensing and inversion modelling, pointing to a major gap in our understanding of the contribution of these ecosystems to CH4 emissions. Here we report CH4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests6 and tropical peat swamp forests, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ13C) of −66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH4 a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a ‘top-down’ regional estimate of CH4 emissions of 42.7 ± 5.6 teragrams of CH4 a year for the Amazon basin, based on regular vertical lower-troposphere CH4 profiles covering the period 2010–2013. We find close agreement between our ‘top-down’ and combined ‘bottom-up’ estimates, indicating that large CH4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH4 source when trees are combined with other emission sources.