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Cited by 69Mercury impact and mitigation studiesEnvironmental Toxicology and EcotoxicologyArsenic contamination and mitigation

Health Risk Assessment of Mercury Exposure from Fish Consumption in Munduruku Indigenous Communities in the Brazilian Amazon

Open access
Vasconcellos, Ana Claudia Santiago de, Hallwass, Gustavo, Bezerra, Jaqueline Gato, Aciole, Angélico Nonato Serrão, Meneses, Heloisa Nascimento de Moura, Lima, Marcelo de Oliveira, Jesus, Iracina Maura de, Hacon, Sandra de Souza +1 more·2021·International Journal of Environmental Research and Public Health
DOI 10.3390/ijerph18157940PMC PMC8345402
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Abstract

Fish serves as the principal source of animal protein for the indigenous people of the Amazon, ensuring their food and nutritional security. However, gold mining causes mercury (Hg) contamination in fish, and consequently increases health risks associated with fish consumption. The aim of this study was to assess the health risk attributed to the consumption of mercury-contaminated fish by Munduruku indigenous communities in the Middle-Tapajós Region. Different fish species were collected in the Sawré Muybu Indigenous Land to determine mercury levels. The health risk assessment was carried out according to the World Health Organization (WHO 2008) methodology and different scenarios were built for counterfactual analysis. Eighty-eight fish specimens from 17 species and four trophic levels were analyzed. Estimates of Hg ingestion indicated that the methylmercury daily intake exceeds the U.S. EPA (United States Environmental Protection Agency) (2000) reference dose from 3 to 25-fold, and up to 11 times the FAO (Food and Agriculture Organization)/WHO (2003) dose recommendation. In all situations analyzed, the risk ratio estimates were above 1.0, meaning that the investigated Munduruku communities are at serious risk of harm as a result of ingestion of mercury-contaminated fish. These results indicate that, at present, fish consumption is not safe for this Munduruku population. This hazardous situation threatens the survival of this indigenous population, their food security, and their culture.

AI snapshot

Written from the paper’s full text.

TL;DR

Mercury in fish from the Sawré Muybu Indigenous Land in the Brazilian Amazon exceeded safe intake thresholds for the Munduruku, with estimated methylmercury intakes 3–25 times the U.S. EPA reference dose and up to 11 times FAO/WHO recommendations. In all scenarios and population strata, risk ratios were >1.0, indicating that current fish consumption is not safe for this population.

Key findings

  • Of 88 fish specimens from 17 species and four trophic levels, mean total mercury was 0.10 µg/g (SD = 0.09; n = 57) in non-piscivorous fish and 0.44 µg/g (SD = 0.34; n = 31) in piscivorous fish; trophic-level differences were significant (H = 60.2; df = 3; p < 0.0001).
  • Bioaccumulation was found only in piscivorous species, with a positive relationship between fish size and total mercury (y = −0.041 + 0.0151X; R² = 0.36; F = 15.4; df = 27; p = 0.0005).
  • 96% of families reported consuming fish regularly (≥3 times a week); estimated daily fish consumption was 216.75 g for adult men, 168.58 g for women of childbearing age, 72.25 g for children over 5 years, and 24.08 g for children under 5 years.
  • Estimated methylmercury intake exceeded the U.S. EPA reference dose by 3- to 25-fold and exceeded FAO/WHO recommendations by up to 11 times; in the current scenario, women of childbearing age ingested 7 times the U.S. EPA dose and 3 times the FAO/WHO safe intake, while the critical scenario reached 23 times and 10 times those limits, respectively.

Methods

  • Fish were captured by Munduruku fishermen using gillnets and handlines in the Sawré Muybu Indigenous Land, Middle-Tapajós Region, Pará, Brazil, during 29 October–9 November 2019; 88 specimens were measured, identified, and sampled for dorsal muscle total mercury by cold vapor atomic absorption spectrometry.
  • Interviews with household heads and weight measurements were conducted in 35 domiciles across three villages; fish consumption was estimated from catch effort, assuming adult men consumed 45%, adult women 35%, children aged 5–12 years 15%, and children aged 2–5 years 5% of captured fish.
  • Health risk assessment followed WHO (2008) methodology, using four scenarios (rainy season, dry season, current, critical) and calculating risk ratios against U.S. EPA (0.1 µg Hg/kg bw/day) and FAO/WHO (0.23 µg Hg/kg bw/day for childbearing-age women and children; 0.45 µg Hg/kg bw/day for adults) reference doses.

Limitations

  • The paper states that measuring actual fish intake in culturally differentiated communities is difficult, that recall methods can over- or underestimate consumption, and that the catch-effort estimate relies on assumptions about fishing effort and intra-household distribution.
  • The paper states that children aged 2–5 years showed a mismatch between estimated intake and hair mercury, possibly due to other exposure routes such as breastfeeding and intrauterine transfer, or because fish consumption was underestimated for this group.
  • The paper states that safe intake doses were derived from longitudinal studies in Seychelles, the Faroe Islands, and New Zealand, populations that differ strongly from Amazonian populations, and that a long-term study is needed to estimate safe doses for Amazonian groups; evident from the text, the study is cross-sectional, based on a single short field campaign in three villages and 35 households, and its risk assessment assumes 100% of fish mercury is methylmercury and 100% is absorbed.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3390/ijerph18157940

Cites

54 of 54 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

19 of 61 cited sources checked · 9 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Amazonian people have one of the highest fish consumption rates in the world.

    “Therefore, it is not surprising that Amazonian people have one of the highest fish consumption rates in the world [10,11,12].”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [10] Isaac, V.J., and Almeida, M.C. (2011). El Consumo de Pescado en la Amazonía Brasileña, FAO.

      Not checked in the free run.

    • cites [11] Isaac, 2015, Food consumption as an indicator of the conservation of natural resources in riverine communities of the Brazilian Amazon, An. Acad. Bras. Ciências source

      The Conclusions say fish consumption rates are among the highest in the world, but the study concerns riverine communities of the Brazilian Amazon, not Amazonian people generally. The Discussion reports 169 kg per person annually in those communities, more than double the average in Japan and other countries with fish-based diets. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [12] Begossi, 2019, Fish consumption on the Amazon: A review of biodiversity, hydropower and food security issues, Braz. J. Biol. source

      The Introduction reports that fish make up a major portion of Amazonian diets and gives average consumption as 169 kg per person per year. It does not compare that rate with rates elsewhere or establish that it is among the world's highest. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
  • Premisecitation

    Mercury used in garimpos is converted into methylmercury, the most dangerous mercurial form to human health.

    “The mercury used in garimpos is converted into methylmercury (MeHg), the most dangerous mercurial form to human health.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [27] Macchi, 2021, Mercury: What can we learn from the Amazon?, Environ. Int. source
  • Premisecitation

    Illegal gold mining has had a sharp increase in the past years due to incentives from the federal government, mainly due to Bill 191/2020.

    “recent studies carried out in the Amazon region indicate that illegal gold mining has had a sharp increase in the past years due to incentives from the federal government, mainly due to Bill 191/2020 presented by President Jair Bolsonaro to Parliament.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [20] Carvalho, 2021, The Brazilian Amazon deforestation rate in 2020 is the greatest of the decade, Nat. Ecol. Evol.

      Not checked in the free run.

    • cites [25] Ferrante, 2019, Brazil’s new president and “ruralists” threaten Amazonia’s environment, traditional peoples and the global climate, Environ. Conserv. source

      The paper’s main text says Bolsonaro wanted to open protected and Indigenous lands to mining, and that his supporters promoted this policy. It does not report a sharp increase in illegal gold mining, establish that government incentives caused one, or mention Bill 191/2020; searches for gold mining and the bill found no such passage. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Premisecitation

    Fillion et al. showed an odds ratio equal to 2.91 (CI 95% 1.26-7.28) for elevated systolic blood pressure among individuals with hair Hg levels above 10 μg/g.

    “Fillion et al. [30] investigated riverine communities in the Amazon and showed an odds ratio equal to 2.91 (CI 95% 1.26–7.28) for elevated systolic blood pressure among individuals with hair Hg levels above 10 µg/g.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Fillion et al. [30] Fillion, 2006, A preliminary study of mercury exposure and blood pressure in the Brazilian Amazon, Environ. Health source
  • Findingcitation

    The analysis of mercury levels in hair of the Munduruku population revealed that there are individuals which presented mercury levels above 20 μg/g.

    “The analysis of the mercury levels in hair of the Munduruku population revealed that, in fact, there are individuals which presented mercury levels above 20 µg/g (more details in Basta et al. [34]).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Basta et al. [34] Basta, P.C., Viana, P.V.S., Vasconcellos, A., Périssé, A., Hofer, C., Paiva, N.S., Kempton, J.W., Ciampi de Andrade, D., Oliveira, R.A.A., and Achatz, R.W. (2021). Mercury exposure in Munduruku indigenous communities from Brazilian Amazon: Methodological background and an overview of the principal results. Int. J. Environ. Res. Public Health, 18, in press. source
  • May combine two claims. 36
  • Classified as probably not a substantial claim. 13
  • The quote only partly states this claim. 1

  • May combine two claims.

    Premisecitation

    The increase in illegal gold mining is largely concentrated in indigenous areas, mainly affecting the Yanomami and Munduruku traditional territories.

    “The situation becomes even more serious because this increase is largely concentrated in indigenous areas, mainly affecting the Yanomami and Munduruku traditional territories [20,25].”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [20] Carvalho, 2021, The Brazilian Amazon deforestation rate in 2020 is the greatest of the decade, Nat. Ecol. Evol.

      Not checked in the free run.

    • cites [25] Ferrante, 2019, Brazil’s new president and “ruralists” threaten Amazonia’s environment, traditional peoples and the global climate, Environ. Conserv. source

      The main text reports increased attacks involving prospectors and proposals to open indigenous lands to mining, but it does not report an increase in illegal gold mining or where such an increase is concentrated. Searches for Yanomami, Munduruku, and gold mining found no passage identifying those territories as chiefly affected. (LLM, conf=0.74)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Methylmercury undergoes bioaccumulation and biomagnification through aquatic trophic chains, and consumption of contaminated fish and other organisms provides the main route of human exposure.

    “Methylmercury undergoes bioaccumulation and biomagnification through aquatic trophic chains and, consequently, the consumption of contaminated fish and other organisms (e.g., crabs, shrimp, turtle, etc.) provides the main route of human exposure to this persistent environmental contaminant [27].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [27] Macchi, 2021, Mercury: What can we learn from the Amazon?, Environ. Int. source

  • May combine two claims.

    Premisecitation

    Methylmercury is especially harmful to pregnant women because the fetal brain is more sensitive, causing neurodevelopment problems.

    “This mercurial form is especially harmful to pregnant women because the fetal brain is more sensitive to the action of methylmercury, causing many neurodevelopment problems to occur, including mental retardation, learning delays, visual and auditory alterations, and other harmful effects [31,32,33].”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [31] Vasconcellos, 2018, Burden of Mild Mental Retardation attributed to prenatal methylmercury exposure in Amazon: Local and regional estimates, Cienc. Saude Coletiva source

      The Introduction and “MMR MeHg-attributed” section say that the fetus is vulnerable to methylmercury exposure and link prenatal exposure to impaired brain development, cognitive loss, and mild mental retardation. The citing sentence also lists learning delays and visual and auditory alterations; our copy does not specifically support those outcomes. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites [32] Poulin, J., Gibb, H., Prüss-Üstün, A., and World Health Organization (2008). Mercury: Assessing the Environmental Burden of Disease at National and Local Levels, World Health Organization.

      Not checked in the free run.

    • cites [33] McCarty, 2010, Mercury exposure and children’s health, Curr. Probl. Pediatric Adolesc. Health Care

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Ingested methylmercury is rapidly absorbed by the human gastrointestinal tract, principally affecting the central nervous and cardiovascular systems.

    “Ingested methylmercury is rapidly absorbed by the human gastrointestinal tract, principally affecting the central nervous and cardiovascular systems [28,29,30].”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [28] Lacerda, 2020, Comparison of visual functions of two Amazonian populations: Possible consequences of different mercury exposure, Front. Neurosci. source

      The Discussion (page unavailable) says methylmercury from food is absorbed in the duodenum and accumulates in nervous tissue; the Introduction (page unavailable) describes neurological effects. The paper does not say gastrointestinal absorption is rapid or identify the cardiovascular system as a principal target. Its statement that absorption is fast refers instead to inhaled mercury vapor entering through the lungs. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [29] Salonen, 1995, Intake of mercury from fish, lipid peroxidation, and the risk of myocardial infarction and coronary, cardiovascular, and any death in eastern Finnish men, Circulation source
    • cites [30] Fillion, 2006, A preliminary study of mercury exposure and blood pressure in the Brazilian Amazon, Environ. Health source

      The Background (page unavailable) identifies fish as a major route of human methylmercury exposure, and the Discussion reports associations between methylmercury exposure and cardiovascular function. Our copy does not say that ingested methylmercury is rapidly absorbed through the gastrointestinal tract. It also describes cardiovascular findings as inconsistent, so it does not establish the claim that methylmercury principally affects the cardiovascular system. (LLM, conf=0.85)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Hu et al. meta-analysis suggests that hair mercury concentration of 2-3 μg/g might be considered as a threshold for risk of developing hypertension.

    “Hu et al. [47] in a meta-analysis suggest that hair mercury concentration of 2–3 µg/g might be considered as a threshold for risk of developing hypertension.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Hu et al. [47] Hu, 2018, Mercury exposure, blood pressure, and hypertension: A systematic review and dose–response meta-analysis, Environ. Health Perspect. source

  • May combine two claims.

    Premisecitation

    Brabo et al. observed that piscivorous species had mean mercury levels of 0.293 μg/g, while non-piscivorous species had average mercury levels equal to 0.112 μg/g in the Sai Cinza region.

    “Brabo et al. [56] investigated fish contamination in the Sai Cinza region, also inhabited by indigenous Munduruku. They observed that the piscivorous species had mean mercury levels of 0.293 µg/g, while the non-piscivorous species had average mercury levels equal to 0.112 µg/g.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Brabo et al. [56] Brabo, 1999, Mercury levels in fish consumed by the Sai Cinza indigenous community, Munduruku Reservation, Jacareacanga County, State of Para, Brazil, Cad. Saúde Pública source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Many studies have already shown mercury contamination in the fauna of the Tapajós River Basin at least two decades ago.

    “Many studies have already shown mercury contamination in the fauna of the Tapajós River Basin at least two decades ago [55,56,57,58,59,60,61,62,63,64,65].”
    Quote in the paperNot a substantial claim3 of 10 sources checked
    • cites [55] Malm, 1995, An assessment of Hg pollution in different goldmining areas, Amazon Brazil, Sci. Total Environ. source
    • cites [56] Brabo, 1999, Mercury levels in fish consumed by the Sai Cinza indigenous community, Munduruku Reservation, Jacareacanga County, State of Para, Brazil, Cad. Saúde Pública source
    • cites [57] Roulet, 2000, Increase in mercury contamination recorded in lacustrine sediments following deforestation in the central Amazon, Chem. Geol. source
    • cites [58] Loureiro, 2000, Mercury exposures in riverside Amazon communities in Para, Brazil, Environ. Res. source
    • cites [59] Barbosa, 2005, Fish consumption (Hair Mercury) and nutritional status of Amazonian Amer-Indian Children, Am. J. Hum. Biol. Off. J. Hum. Biol. Assoc. source
    • cites [60] Telmer, 2006, The source and fate of sediment and mercury in the Tapajós River, Pará, Brazilian Amazon: Ground-and space-based evidence, J. Environ. Manag. source
    • cites [61] Hacon, 2008, An overview of mercury contamination research in the Amazon basin with an emphasis on Brazil, Cad. Saúde Pública source

      The Introduction (page not specified) says mercury contamination of Amazonian biota was well documented and describes Tapajós residents consuming contaminated food. The Results and discussion (page not specified) identifies the Tapajós as a major research site. These passages support the general point, but do not establish that many studies had specifically demonstrated contamination of Tapajós fauna at least two decades before the citing sentence. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [62] Passos, 2008, Daily mercury intake in fish-eating populations in the Brazilian Amazon, J. Expo. Sci. Environ. Epidemiol. source
    • cites [63] Faial, 2015, Mercury levels assessment in hair of riverside inhabitants of the Tapajós River, Pará State, Amazon, Brazil: Fish consumption as a possible route of exposure, J. Trace Elem. Med. Biol. source
    • cites [64] Freitas, J.S., Lacerda, E., Maria, C., Rodrigues, D., Corvelo, T.C.O., Silveira, L.C.L., and Souza, G.S. (2019). Mercury exposure of children living in Amazonian villages: Influence of geographical location where they lived during prenatal and postnatal development. An. Acad. Bras. Ciências, 91. source

  • May combine two claims.

    Premisecitation

    Frequently, the fish intake of riverside communities exceeds 300 g per day, resulting in annual average consumption that could surpass 100 kg per capita.

    “Frequently, the fish intake of riverside communities exceeds 300 g per day, resulting in annual average consumption that could surpass 100 kg per capita [10,45,46].”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites [10] Isaac, V.J., and Almeida, M.C. (2011). El Consumo de Pescado en la Amazonía Brasileña, FAO.

      Not checked in the free run.

    • cites [45] Cerdeira, 1997, Consumo de pescado e outros alimentos pela população ribeirinha do lago grande de Monte Alegre, PA-Brasil, Acta Amaz. source
    • cites [46] Batista, V.D., Isaac, V.J., and Viana, J.P. (2004). Exploração e Manejo Dos Recursos Pesqueiros da Amazônia. A Pesca e os Recursos Pesqueiros na Amazônia Brasileira, Ibama/ProVárzea.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Fish consumption among Munduruku indigenous people can be considered high, at least three meals per day, varying slightly between different groups.

    “On the other hand, fish consumption among Munduruku indigenous people can be considered high (at least three meals per day), varying slightly between different groups [56,58,59].”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [56] Brabo, 1999, Mercury levels in fish consumed by the Sai Cinza indigenous community, Munduruku Reservation, Jacareacanga County, State of Para, Brazil, Cad. Saúde Pública source

      The Resultados passage (page not specified in the excerpt) reports that fish was a daily dietary staple for all 330 interviewees in Sai Cinza and was eaten at least three times a day. It does not compare consumption between different Munduruku groups or establish that it varies slightly between them. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [58] Loureiro, 2000, Mercury exposures in riverside Amazon communities in Para, Brazil, Environ. Res. source
    • cites [59] Barbosa, 2005, Fish consumption (Hair Mercury) and nutritional status of Amazonian Amer-Indian Children, Am. J. Hum. Biol. Off. J. Hum. Biol. Assoc. source

  • May combine two claims.

    Premisecitation

    The mean mercury level in male hair was 8.83 μg/g (SD: 4.56) and in women of childbearing age, the mean hair mercury level was 7.71 μg/g (SD: 3.88).

    “The mean mercury level in male hair was 8.83 µg/g (SD: 4.56) and in women of childbearing age, the mean hair mercury level was 7.71 µg/g (SD: 3.88).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [34] Basta, P.C., Viana, P.V.S., Vasconcellos, A., Périssé, A., Hofer, C., Paiva, N.S., Kempton, J.W., Ciampi de Andrade, D., Oliveira, R.A.A., and Achatz, R.W. (2021). Mercury exposure in Munduruku indigenous communities from Brazilian Amazon: Methodological background and an overview of the principal results. Int. J. Environ. Res. Public Health, 18, in press. source

      Results §3.2.1 reports an overall hair-mercury mean of 7.7 µg/g (SD 4.5) and some village-specific means for men and women. Searches for 8.83, 7.71, and the claimed subgroup statistics found no passage in our copy reporting either claimed mean and SD. (LLM, conf=0.74)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data

    Average mercury levels in non-piscivorous fish (n = 57) was 0.10 μg/g (SD = 0.09) and in piscivorous fish (n = 31) was 0.44 μg/g (SD = 0.34).

    “The average mercury levels in samples of non-piscivorous fish (n = 57) was 0.10 µg/g (SD = 0.09) and the average for piscivorous fish (n = 31) was 0.44 µg/g (SD = 0.34).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Average daily fish consumption estimates: adult men 216.75 g (45%), childbearing age women 168.58 g (35%), children over 5 72.25 g (15%), children under 5 24.08 g (5%).

    “The average daily fish consumption estimates for the studied groups were the following: adult men consume 216.75 g (corresponding to 45% of the fish available for consumption), childbearing age women consume 168.58 g (35%), children over 5 years consume 72.25 g (15%), and children under 5 years consume 24.08 g (5%) (Table 2).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The effort of the Munduruku fishermen to catch fish during this fieldwork was similar to the fishing effort usually devoted by the heads of households.
    • The authors state this as an assumption: Adult men consume 45% of the fish captured, adult women consume 35%, children aged 5 to 12 years consume 15%, and children from 2 to 5 years old consume 5%.

  • May combine two claims.

    Findingown data

    Estimates of Hg ingestion indicated that the methylmercury daily intake exceeds the U.S. EPA (2000) reference dose from 3 to 25-fold, and up to 11 times the FAO/WHO (2003) dose recommendation.

    “Estimates of Hg ingestion indicated that the methylmercury daily intake exceeds the U.S. EPA (United States Environmental Protection Agency) (2000) reference dose from 3 to 25-fold, and up to 11 times the FAO (Food and Agriculture Organization)/WHO (2003) dose recommendation.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites U.S. EPA (2000)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites FAO/WHO (2003)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • The authors state this as an assumption: 100% of the mercury detected in the fish sample is in the form of methylmercury.
    • The authors state this as an assumption: 100% of the methylmercury available in the fish muscle tissue is absorbed in the human’s gastrointestinal tract.

  • May combine two claims.

    Findingown data

    Among participants, 53 were women of childbearing age, 58 were adult men, 24 were children aged 5 to 12, and 42 were children aged 2 to 5.

    “Among the participants, 53 were women of childbearing age (12 to 49 years old), 58 were adult men (≥12 years old), 24 were children aged 5 to 12 years old, and 42 were children aged 2 to 5 years.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    Families are composed on average of 4 members (two adults and two children).

    “The interviews revealed that families are composed on average of 4 members (i.e., two adults and two children).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Average weights: women of childbearing age 49.89 kg, adult men 56.45 kg, children over 5 24.45 kg, children under 5 14.07 kg.

    “According to the data collected in the fieldwork, the women of childbearing age had an average weight of 49.89 kg, adult men were 56.45 kg, children over 5 years old were 24.45 kg, and children under 5 years old were 14.07 kg (Table 2).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    During fieldwork, 35 domiciles were visited: 20 in Sawré Muybu, 8 in Poxo Muybu, and 7 in Sawré Aboy.

    “During the fieldwork, our team visited 35 domiciles: 20 in the Sawré Muybu village, 8 in the Poxo Muybu village, and 7 in the Sawré Aboy village.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    There was a significant difference in total mercury concentration in muscle tissues among trophic levels (H = 60.2; df = 3; p < 0.0001), confirming biomagnification.

    “The biomagnification in the trophic chain of fish was confirmed, as there was a significant difference in the concentration of total mercury in muscle tissues among trophic levels (H = 60.2; df = 3; p < 0.0001) (Figure 1a).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Bioaccumulation was found only in piscivorous species, with a positive and significant relationship between fish size and THg concentration (y = −0.041 + 0.0151X; R2 = 0.36; F = 15.4; df = 27; p = 0.0005).

    “In addition, bioaccumulation was found only in piscivorous species, where there was a positive and significant relationship between the size of the fish and the THg concentration in the muscle tissues (y = −0.041 + 0.0151X; R2 = 0.36; F = 15.4; df = 27; p = 0.0005) (Figure 1b).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In all scenarios created for counterfactual analysis, the estimated risk ratios are greater than 1.0, indicating that the intake of mercury by the groups studied is higher than the limits proposed by health agencies.

    “In all of the scenarios created for counterfactual analysis, the estimated risk ratios are greater than 1.0, indicating that the intake of mercury by the groups studied is higher than the limits proposed by health agencies.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The mean amount of fish caught on a typical fishing day represents the amount of fish that a Munduruku family consumes over a week.
    • The authors state this as an assumption: The current scenario represents the mercury exposure scenario that most closely matches the local reality.
    • Rests on an assumption: The safety parameters proposed by FAO/WHO and U.S. EPA are applicable to the Munduruku population for assessing risk from mercury intake.

  • May combine two claims.

    Findingown data

    In the critical scenario, women of childbearing age ingest 10 times more mercury than the limit proposed by FAO/WHO, and 23 times more mercury than the safe limit proposed by U.S. EPA.

    “In this case, women of childbearing age ingest 10 times more mercury than the limit proposed by the FAO/WHO, and 23 times more mercury than the safe limit proposed by the U.S. EPA.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: 100% of the mercury detected in the fish sample is in the form of methylmercury.
    • The authors state this as an assumption: 100% of the methylmercury available in the fish muscle tissue is absorbed in the human’s gastrointestinal tract.

  • May combine two claims.

    Findingown data

    Piscivorous fish were the only trophic level where a positive relationship between fish size and total Hg concentration was found, indicating bioaccumulation.

    “Indeed, piscivorous fish were the only trophic level where we found a positive relationship between fish size and total Hg concentration, indicating bioaccumulation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The population stratum of children aged 2 to 5 years did not indicate compatibility between intake and concentration in hair; the daily intake was estimated at 0.37 μg/bw kg/day and the average hair concentration was 6.68 μg/g (SD: 3.44).

    “Only the population stratum constituted by children aged 2 to 5 years did not indicate compatibility between intake and concentration in hair. In this case, the daily intake was estimated at 0.37 µg/bw kg/day and the average concentration in hair was 6.68 µg/g (SD: 3.44).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The mean amount of fish caught on a typical fishing day represents the amount of fish that a Munduruku family consumes over a week.
    • The authors state this as an assumption: The current scenario represents the mercury exposure scenario that most closely matches the local reality.

  • May combine two claims.

    Findingown data

    Risk ratio estimate for the critical scenario was 5.0 and 5.75 in children and adults, respectively.

    “The risk ratio estimate for the critical scenario was 5.0 and 5.75 in children and adults, respectively (Table 3).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    Quality assurance/quality control for mercury analysis used reference materials DOLT-4 and DORM-3, a method blank, a 6-point calibration curve, and had RSD 8.32% and LOD/LOQ 0.0083/0.027 ng/mg.

    “To guarantee the Quality Assurance (QA)/ Quality Control (QC), we used for the mercury analysis in fish samples the following parameters: (i) reference materials dogfish liver certified reference material for trace metals (DOLT-4) (% of recovery: 92.24 ± 7.73; 70.92 to 100) and fish protein certified reference material for trace metals (DORM-3) (% of recovery: 96.22 ± 4.69; 87.16 to 100) from the”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Fish is a vital element for Amazonian populations, especially for indigenous and riverine populations.

    “These reasons make fish a vital element for Amazonian populations, especially for indigenous and riverine populations.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Gold mining causes mercury contamination in fish, and consequently increases health risks associated with fish consumption.

    “However, gold mining causes mercury (Hg) contamination in fish, and consequently increases health risks associated with fish consumption.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [23] Malm, 1998, Gold mining as a source of mercury exposure in the Brazilian Amazon, Environ. Res. source
    • cites [24] Kalamandeen, 2020, Limited biomass recovery from gold mining in Amazonian forests, J. Appl. Ecol. source

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based). May combine two claims.

    Interpretationreasoning

    This hazardous situation threatens the survival of this indigenous population, their food security, and their culture.

    “This hazardous situation threatens the survival of this indigenous population, their food security, and their culture.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Fish serves as the principal source of animal protein for the indigenous people of the Amazon, ensuring their food and nutritional security.

    “Fish serves as the principal source of animal protein for the indigenous people of the Amazon, ensuring their food and nutritional security.”
    • Also stated in: § 1. Introduction · plain
      “Fish has an important role in food security, since 17% of all animal protein consumed in the world is provided by fish [1].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [1] FAO (2020). The State of World Fisheries and Aquaculture, FAO.

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    The health risk assessment was carried out according to the World Health Organization (WHO) methodology.

    “The health risk assessment was carried out according to the methodology proposed by World Health Organization (WHO) [39].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [39] World Health Organization (2008). Guidance for Identifying Populations at Risk from Mercury Exposure, Mercury Publications.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Mercury is a toxic heavy metal that contaminates the atmosphere, waters, sediments, and organisms.

    “Mercury is a toxic heavy metal that contaminates the atmosphere, waters, sediments, and organisms [23,24].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [23] Malm, 1998, Gold mining as a source of mercury exposure in the Brazilian Amazon, Environ. Res. source
    • cites [24] Kalamandeen, 2020, Limited biomass recovery from gold mining in Amazonian forests, J. Appl. Ecol. source

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationreasoning

    The mercury contamination observed in fish and the indigenous Munduruku is a direct consequence of gold mining and the Brazilian authorities' longstanding refusal to condemn this activity, threatening the health and rights of the native peoples.

    “The mercury contamination observed in fish and the indigenous Munduruku is a direct consequence of gold mining and the Brazilian authorities’ longstanding refusal to condemn this activity, threatening the health and rights of the native peoples.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The larger the size of piscivorous fish, the higher the mercury concentration in their tissues and thus the higher the health risk for people who eat the larger ones.

    “Therefore, the larger the size of piscivorous fish, the higher the mercury concentration in their tissues and thus the higher the health risk for people who eat the larger ones.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Salonen et al. concluded that hair mercury levels above 2.0 μg/g represent a risk 69% higher for an acute myocardial infarction.

    “Salonen et al. [29], in a longitudinal study with Finnish men, concluded that hair mercury levels above 2.0 µg/g represent a risk 69% higher for an acute myocardial infarction.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Salonen et al. [29] Salonen, 1995, Intake of mercury from fish, lipid peroxidation, and the risk of myocardial infarction and coronary, cardiovascular, and any death in eastern Finnish men, Circulation source

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    The contamination of fish by mercury and all related health damages are caused (or intensified) by exploitation of gold.

    “it is essential to clarify that the contamination of fish by mercury and all related health damages are caused (or intensified) by exploitation of gold.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The population living in the Middle-Tapajós Region consumes contaminated fish and compromises their health.

    “Consequently, the population living in this region consumes contaminated fish and compromises their health.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationnone given

    The current gold mining activity in the Middle-Tapajós Region is causing environmental devastation, social conflict, and increasing mercury levels in the environment.

    “The current gold mining activity in the Middle-Tapajós Region is causing environmental devastation, social conflict, and increasing mercury levels in the environment.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    The mean mercury levels detected in piscivorous species are about 4 times greater than non-piscivorous species, highlighting methylmercury biomagnification.

    “These studies corroborate the present results that the mean mercury levels detected in piscivorous species are about 4 times greater than non-piscivorous species, highlighting the methylmercury biomagnification.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    Illegal gold mining is the principal cause of mercury contamination in the region.

    “In conclusion, we recommend the immediate closure of illegal gold mining in the Brazilian Amazon, the principal cause of mercury contamination in the region.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductreasoning

    Children aged 5 to 12 years had a mercury daily intake dose matching the levels of mercury in hair; the intake dose was estimated at 0.64 μg/bw kg/day and the average hair mercury level was 7.62 μg/g (SD: 5.44).

    “Children from 5 to 12 years old also had a mercury daily intake dose matching with the levels of mercury in hair. The intake dose was estimated at 0.64 µg/bw kg/day and the average level of mercury in hair was 7.62 µg/g (SD: 5.44).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The mean amount of fish caught on a typical fishing day represents the amount of fish that a Munduruku family consumes over a week.
    • The authors state this as an assumption: The current scenario represents the mercury exposure scenario that most closely matches the local reality.

  • May combine two claims.

    Premisecitation

    The limits established by FAO/WHO were adopted in 1991 and do not consider health effects produced by the ingestion of methylmercury in the fish.

    “these limits established by the FAO/WHO were adopted in 1991 and do not consider health effects produced by the ingestion of methylmercury in the fish [67].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [67] FAO/WHO (2020, June 22). Joint FAO/WHO Expert Committee on Food Additives (JECFA), Report of the Tenth Section, Rotterdam, The Netherlands 4 to 8 April 2016. Available online: http://www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=https%253A%252F%252Fworkspace.fao.org%252Fsites%252Fcodex%252FMeetings%252FCX-735-10%252FReport%252FREP16_CFe.pdf.

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The longitudinal studies mentioned above considered populations that differ strongly from Amazonian populations and probably present mercury exposure thresholds for toxic health outcomes quite different from the indigenous communities.

    “However, the longitudinal studies mentioned above considered populations that differ strongly from the Amazonian populations and, probably, present mercury exposure thresholds for toxic health outcomes quite different from the indigenous communities.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    FAO/WHO recommended limits are 0.5 μg MeHg/g for non-piscivorous fish and 1.0 μg MeHg/g for piscivorous fish.

    “the limits recommended by FAO/WHO [67] (0.5 µg MeHg/g for non-piscivorous fish and 1.0 µg MeHg/g for piscivorous fish).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [67] FAO/WHO (2020, June 22). Joint FAO/WHO Expert Committee on Food Additives (JECFA), Report of the Tenth Section, Rotterdam, The Netherlands 4 to 8 April 2016. Available online: http://www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=https%253A%252F%252Fworkspace.fao.org%252Fsites%252Fcodex%252FMeetings%252FCX-735-10%252FReport%252FREP16_CFe.pdf.

      Not checked in the free run.

43 of 43

  • The authors state this as an assumption.

    The effort of the Munduruku fishermen to catch fish during this fieldwork was similar to the fishing effort usually devoted by the heads of households.

    “we assumed as a premise that the effort of the Munduruku fishermen to catch fish during this fieldwork was similar to the fishing effort usually devoted by the heads of households.”

  • The authors state this as an assumption.

    Adult men consume 45% of the fish captured, adult women consume 35%, children aged 5 to 12 years consume 15%, and children from 2 to 5 years old consume 5%.

    “we assumed that adult men consume 45% of the fish captured, adult women consume 35%, children aged 5 to 12 years consume 15%, while children from 2 to 5 years old consume only 5%.”

  • The authors state this as an assumption.

    100% of the mercury detected in the fish sample is in the form of methylmercury.

    “(i) 100% of the mercury detected in the fish sample is in the form of methylmercury”

  • The authors state this as an assumption.

    100% of the methylmercury available in the fish muscle tissue is absorbed in the human’s gastrointestinal tract.

    “(ii) 100% of the methylmercury available in the fish muscle tissue is absorbed in the human’s gastrointestinal tract.”

  • The authors state this as an assumption.

    The mean amount of fish caught on a typical fishing day represents the amount of fish that a Munduruku family consumes over a week.

    “Thus, the mean amount of fish caught on a typical fishing day represents the amount of fish that a Munduruku family consumes over a week.”

  • The paper relies on this without support.

    Memory-based methods (recall method) about what was consumed by the family in the past 24 h or in the past few days generally produce over- or underestimated data that rarely translate into reality and cause errors in estimates.

    “Memory-based methods (recall method) about what was consumed by the family in the past 24 h or in the past few days generally produce over or underestimated data that rarely translate into reality and cause errors in estimates.”

  • The authors state this as an assumption.

    The current scenario represents the mercury exposure scenario that most closely matches the local reality.

    “The current scenario was built to represent the mercury exposure scenario that most closely matches the local reality.”

  • The paper relies on this without support.

    Piscivorous fish have higher levels of mercury.

    “In the rainy season, according to the interview reports, 60% of fish most consumed by the Munduruku families are piscivorous and therefore have higher levels of mercury.”

  • The paper relies on this without support.

    The safety parameters proposed by FAO/WHO and U.S. EPA are applicable to the Munduruku population for assessing risk from mercury intake.

    “According to the safety parameters proposed by FAO/WHO [41] and U.S. EPA [40], the entire study population is at risk of becoming ill due to the consumption of methylmercury contaminated fish.”
9 of 9

Cites

Flagged first, then by citations

1 of the 55 references couldn’t be matched to a known paper.

Research works printed but not linked: 3

  1. FAO/WHO (2003, January 10–19). Evaluation of certain food additives and contaminants: Sixty-first report of the Joint FAO/WHO Expert Committee on Food Additives. Proceedings of the Joint FAO/WHO Expert Committee on Food Additives (JECFA), Rome, Italy.
  2. Lima, 2017, Emotional and motor symptoms in riverside dwellers exposed to mercury in the Amazon, Rev. Bras. De Epidemiol., 20, 212
  3. Holmes, 1984, Non-dietary modifiers of nutritional status in tropical forest populations of Venezuela, Interciencia, 9, 386

Cited by

Sorted by citations

Related

Authors
Vasconcellos, A. C. S. D., Hallwass, G., Bezerra, J. G., Aciole, A. N. S., Meneses, H. N. D. M., Lima, M. D. O., Jesus, I. M. D., Hacon, S. D. S., & Basta, P. C.
Affiliations
  • Laboratory of Professional Education in Health Surveillance, Joaquim Venâncio Polytechnic School of Health, Oswaldo Cruz Foundation, 21040-900 Rio de Janeiro, Brazil
  • Laboratory of Human Ecology, Fish, Fisheries and Conservation, Postgraduate Program in Biosciences, Federal University of West Para, 68270-000 Oriximiná, Brazil
  • Laboratory of Molecular Epidemiology, Postgraduate Program in Health Sciences, Federal University of West Para, 68040-470 Santarém, Brazil
  • Ministério da Saúde (BR)
  • Escola Nacional de Saúde Pública Sergio Arouca (BR)
Corresponding author
Basta, Paulo Cesar
ORCID
Venue
International Journal of Environmental Research and Public Health
Publisher
MDPI AG
Published
2021-07-27
Volume
18
Issue
15
Pages
7940
ISSN
1660-4601 (ISSN-L)
DOI
10.3390/ijerph18157940
PMC
PMC8345402
OpenAlex
W3185103398
Semantic Scholar
41478765c49e8cf49126e19801e7a011e478ea31
Cited by
69
References
55
Citations by year
2026: 12 · 2025: 14 · 2024: 22 · 2023: 13 · 2022: 3 · 2021: 5
FWCI
4.26
Type
journal article
Language
en
Open access
Licence
Locations
  • International Journal of Environmental Research and Public Health (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • RePEc: Research Papers in Economics (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (submittedVersion, other-oa)
Topics
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Mercury impact and mitigation studies
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Environmental Toxicology and Ecotoxicology
  • Physical Sciences › Environmental Science › Environmental Chemistry › Arsenic contamination and mitigation
Keywords
mercury contamination, fish consumption, methylmercury, health risk assessment, gold mining, Tapajós River, trophic levels, food security, indigenous peoples, counterfactual scenarios
MeSH terms
Animals, Brazil, Environmental Exposure, Environmental Monitoring, Fishes, Food Contamination, Humans, Mercury, Methylmercury Compounds, Mining, Risk Assessment

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-11-03.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-11-03.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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