Mercury exposure in Munduruku indigenous communities from Brazilian Amazon: methodological background and an overview of the principal results

This research was funded by the Vice-Presidency of Environment, Care and Health Promotion (VPPAS) of Fundação Oswaldo Cruz (Fiocruz) through Decentralized Execution of Resources Document No. 175/2018, Process: 25000.209221/2018-18, signed between the Fiocruz and the Special Department for Indigenous Health, both under the Ministry of Health. The non-governmental organization WWF-Brazil offered financial support to disseminate the results of the research.Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública. Departamento de Endemias Samuel Pessoa. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública. Centro de Referência Professor Hélio Fraga. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Escola Politécnica de Saúde Joaquim Venâncio. Laboratório de Educação Profissional em Vigilância em Saúde. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública. Departamento de Endemias Samuel Pessoa. Rio de Janeiro, RJ, Brazil.Universidade Federal do Rio de Janeiro. Faculdade de Medicina. Instituto de Pediatria e Puericultura Martagão Gesteira. Rio de Janeiro, RJ, Brazil.Universidade Federal do Rio de Janeiro. Instituto de Estudos em Saúde Coletiva. Rio de Janeiro, RJ, Brazil.Imperial College London. Faculty of Medicine. Medical School Building. St Mary’s Hospital. Norfolk Place, London, UK.Universidade de São Paulo. Faculdade de Medicina. Hospital das Clínicas. Centro de Dor, Departamento de Neurologia. São Paulo, SP, Brazil.Universidade de São Paulo. Faculdade de Medicina. Hospital das Clínicas. Centro de Dor, Departamento de Neurologia. São Paulo, SP, Brazil.Universidade de São Paulo. Instituto de Psicologia. Programa de Pós-Graduação em Psicologia Clínica. São Paulo, SP, Brazil.Centro Universitário Estadual da Zona Oeste. Laboratório de Pesquisa de Ciências Farmacêuticas. Rio de Janeiro, RJ, Brazil.Universidade Federal do Oeste do Pará - Unidade Tapajós. Programa de Pós-Graduação em Ciências da Saúde. Santarém, PA, Brazil.Universidade Federal do Oeste do Pará. Programa de Pós-Graduação em Biociências. Santarém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Secretaria Especial de Saúde Indígena Tapajós. Distrito Sanitário Especial Indígena Rio Tapajós. Itaituba, PA, Brazil.Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública. Departamento de Endemias Samuel Pessoa. Rio de Janeiro, RJ, Brazil.The Amazonian indigenous peoples depend on natural resources to live, but human activities’ growing impacts threaten their health and livelihoods. Our objectives were to present the principal results of an integrated and multidisciplinary analysis of the health parameters and assess the mercury (Hg) exposure levels in indigenous populations in the Brazilian Amazon. We carried out a cross-sectional study based on a census of three Munduruku indigenous villages (Sawré Muybu, Poxo Muybu, and Sawré Aboy), located in the Sawré Muybu Indigenous Land, between 29 October and 9 November 2019. The investigation included: (i) sociodemographic characterization of the participants; (ii) health assessment; (iii) genetic polymorphism analysis; (iv) hair mercury determination; and (v) fish mercury determination. We used the logistic regression model with conditional Prevalence Ratio (PR), with the respective 95% confidence intervals (CI95%) to explore factors associated with mercury exposure levels ≥6.0 µg/g. A total of 200 participants were interviewed. Mercury levels (197 hair samples) ranged from 1.4 to 23.9 μg/g, with significant differences between the villages (Kruskal–Wallis test: 19.9; p-value < 0.001). On average, the general prevalence of Hg exposure ≥ 6.0 µg/g was 57.9%. For participants ≥12 years old, the Hg exposure ≥6.0 µg/g showed associated with no regular income (PR: 1.3; CI95%: 1.0–1.8), high blood pressure (PR: 1.6; CI95%: 1.3–2.1) and was more prominent in Sawré Aboy village (PR: 1.8; CI95%: 1.3–2.3). For women of childbearing age, the Hg exposure ≥6.0 µg/g was associated with high blood pressure (PR: 1.9; CI95%: 1.2–2.3), with pregnancy (PR: 1.5; CI95%: 1.0–2.1) and was more prominent among residents in Poxo Muybu (PR: 1.9; CI95%: 1.0–3.4) and Sawré Aboy (PR: 2.5; CI95%: 1.4–4.4) villages. Our findings suggest that chronic mercury exposure causes harmful effects to the studied indigenous communities, especially considering vulnerable groups of the population, such as women of childbearing age. Lastly, we propose to stop the illegal mining in these areas and develop a risk management plan that aims to ensure the health, livelihoods, and human rights of the indigenous people from Amazon Basin