In the Brazilian Amazon, where the majority of Yanomami villages are settled, mercury (Hg) exposure due to artisanal small-scale gold mining (ASGM) has been reported since the 1980s. This study assessed mercury exposure in the Yanomami reserve and whether the level of contamination was related to the ASGM geographical location. It was conducted using a cross-sectional study of 19 villages. Direct interviews were performed and hair samples were used as a bioindicator of Hg exposure. The Prevalence-Ratio (PR) was estimated as an indicator of association between ASGM geographical locations and human exposure to mercury. Mercury levels (239 hair samples) ranged between 0.4 and 22.1 μg·g−1 and presented substantial differences amongst the villages. In the Waikas-Aracaça region, where current ASGM was reported, we observed the highest Hg concentrations (median = 15.5 μg·g−1). Almost all participants presented with hair-Hg levels >6 μg·g−1 (prevalence = 92.3%). In the Paapiu region, we observed the lowest concentrations (median = 3.2 μg·g−1; prevalence = 6.7%). Our findings showed that the Waikas Ye’kuana and Waikas Aracaca villages presented with 4.4 (PR = 4.4; Confidence Interval (CI) 95% = 2.2–9.0) and 14.0 (PR = 14.0; CI 95% = 7.9–24.9) times higher prevalence of hair-Hg concentration, respectively, compared with Paapiu. Considering seasonal variation of Hg-exposure, the lowest concentrations were observed during the wet season (June–September) and the highest in the dry season (December–April). Our study suggests that there is an association between mercury exposure and ASGM geographical locations.

Resumo O objetivo do estudo foi avaliar o estado nutricional de crianças e mulheres indígenas Yanomami e elucidar fatores associados. Estudo transversal, realizado em 17 aldeias, em 2014. Para a avaliação do estado nutricional utilizou-se as curvas de crescimento de 2006 e os escores-Z (ESZ) de estatura/idade (E/I), peso/idade (P/I), peso/estatura (P/E), os quais foram gerados nos programas WHO-Anthro e WHO-AnthroPlus. Estatura inferior a 145cm foi o descritor de baixa estatura materna nas > 18 anos. A regressão de Poisson e as análises estatísticas foram efetuadas no software R, versão 3.1.2. Nos < 5 anos a prevalência de baixa E/I foi 83,8%, de baixo P/I 50%, de baixo P/E 5,4% e de sobrepeso 2,7%. Em 59,5% das crianças observou-se muito baixa E/I e em 68,1% das mães baixa estatura. As crianças de 36-59 meses apresentaram maior risco de baixa estatura severa, em comparação com as de 0,1-23 (RP = 1,3; IC 95%: 1,1-2,3), assim como os filhos de mães com estatura < 145cm, em relação aos filhos de mães com estatura > 144cm (RP = 2,1; IC 95%;1,2-3,6). As alarmantes prevalências de baixa estatura severa revelam a grave situação nutricional das crianças. Já a associação de baixa estatura severa nas crianças e baixa estatura materna reflete o caráter intergeracional do problema.

The aim of this study was to assess the health risk attributable to the consumption of mercury-contaminated fish for the urban and non-urban populations living in the Roraima state, Amazon, Brazil. Seventy-five fish specimens distributed across twenty different species, comprising four trophic levels (i.e., herbivore, omnivore, detritivore, and carnivore), were collected at four locations in the Branco River Basin. The fish samples were sent to the Toxicology Laboratory at Evandro Chagas Institute to determine the total-Hg levels by using the cold vapor atomic system (CVAAS). The total-Hg levels ranged from 0 to 3.159 µg/g. The average concentration in non-carnivorous species (n = 32) was 0.116 µg/g, and among carnivorous fish (n = 43), it was 0.869 µg/g. The weighted average of contamination levels for all samples was 0.545 µg/g. The health risk assessment was conducted according to the methodology proposed by the World Health Organization and different scenarios of human exposure were considered, based on three levels of fish consumption (low: 50 g/day; moderate: 100 g/day and high: 200 g/day). Women of childbearing age ingest 5 to 21 times more mercury than the dose considered safe by the U.S. EPA and intake a dose from 2 to 9 times higher than the safe dose proposed by FAO/WHO. Children under 5 years of age ingest from 18 to 75 times the dose proposed by the U.S. EPA and from 8 to 32 more mercury than the limit proposed by FAO/WHO. In summary, regardless of the level of fish consumption, type of residency (urban or non-urban), and the subset of the population analyzed, anyone who consumes fish from the locations sampled is at high risk attributable to mercury ingestion, with the only exception of adult men, who consume an average of 50 g of fish per day.