Abstract: Introduction: In some Amazonian river basins, hair mercury concentration is above the recommended levels. We evaluated the influence of birth geographical location in the hair mercury level of Amazonian riverine children. Materials and Methods: Hair mercury concentration was measured in 219 children living in four Amazonian riverine communities: Tapajós River (São Luiz do Tapajós and Barreiras villages, n = 110), Tocantins River (Limoeiro do Ajurú village, n = 61), and Caeté River (Caratateua village, n = 48). We used Poisson regression analysis to evaluate the association between native and non-native children from each village and its hair mercury concentration. Results: Higher mercury exposure was found in native children from São Luiz do Tapajós (range = 0.81-22.38 µg/g) followed by native children from Barreiras (range = 0.48-13.46 µg/g), non-native children from São Luiz do Tapajós (range = 0.26-22.18 µg/g), non-native children from Barreiras (range = 0.43-20.76 µg/g), followed by the children from Caeté and Tocantins river basins. We observed that Tapajós villages’ native children had higher prevalence of mercury exposure children than other children (p < 0.05). Conclusions: Birth geographical location has association to mercury levels in the hair of children who lived in a same community with history of mercury exposure.

Resumo Comunidades ribeirinhas estão expostas ao mercúrio devido à dieta composta por elevada ingestão de peixes. Com o objetivo de avaliar os níveis de exposição na região do Tapajós, identificando também a frequência de ingestão de pescado, realizou-se um estudo em adultos residentes nas comunidades ribeirinhas do município de Itaituba/PA. Foram coletadas amostras de cabelo para a determinação de mercúrio total e dados de frequência semanal de ingestão de peixes. A concentração média de mercúrio total variou de 7,25µg/g (em 2013) para 10,80µg/g (em 2014), não sendo observada diferença significativa (p = 0,1436). Quanto à frequência de ingestão de pescado, a maioria dos indivíduos avaliados apresentou um alto consumo, tanto em 2013 quanto em 2014. Índices elevados de mercúrio total foram observados somente naqueles com alto consumo de pescado em ambos anos. Ressalta-se a importância da continuação do monitoramento dos níveis de exposição em humanos, fundamentando-se nos índices de tolerância de 6µg/g preconizado pela Organização Mundial de Saúde, e na investigação quanto ao consumo de peixes para que as estratégias de controle e prevenção sejam melhoradas.

Abstract Riverine communities are exposed to mercury due to the high ingestion of fish in their diet. In order to evaluate the levels of exposure in the Tapajós region, also assessing the fish ingestion frequency, a study was conducted in adults living in riverine communities in the municipality of Itaituba in the State of Pará. Hair samples were collected for the determination of total mercury and the weekly frequency data of fish ingestion was recorded. The mean concentration of total mercury varied from 7.25μg/g (in 2013) to 10.80μg/g (in 2014), with no significant difference being observed (p = 0.1436). As for fish ingestion frequency, the majority of the individuals evaluated revealed high consumption both in 2013 and in 2014. High levels of total mercury were observed only in those with high consumption of fish in both years. The importance of ongoing monitoring of exposure levels in humans should be stressed, basing itself on indices of tolerance of 6μg/g recommended by the World Health Organization, and investigation about the consumption of fish such that strategies for control and prevention are improved.

Resumo Comunidades ribeirinhas estão expostas ao mercúrio devido à dieta composta por elevada ingestão de peixes. Com o objetivo de avaliar os níveis de exposição na região do Tapajós, identificando também a frequência de ingestão de pescado, realizou-se um estudo em adultos residentes nas comunidades ribeirinhas do município de Itaituba/PA. Foram coletadas amostras de cabelo para a determinação de mercúrio total e dados de frequência semanal de ingestão de peixes. A concentração média de mercúrio total variou de 7,25µg/g (em 2013) para 10,80µg/g (em 2014), não sendo observada diferença significativa (p = 0,1436). Quanto à frequência de ingestão de pescado, a maioria dos indivíduos avaliados apresentou um alto consumo, tanto em 2013 quanto em 2014. Índices elevados de mercúrio total foram observados somente naqueles com alto consumo de pescado em ambos anos. Ressalta-se a importância da continuação do monitoramento dos níveis de exposição em humanos, fundamentando-se nos índices de tolerância de 6µg/g preconizado pela Organização Mundial de Saúde, e na investigação quanto ao consumo de peixes para que as estratégias de controle e prevenção sejam melhoradas.

Abstract Riverine communities are exposed to mercury due to the high ingestion of fish in their diet. In order to evaluate the levels of exposure in the Tapajós region, also assessing the fish ingestion frequency, a study was conducted in adults living in riverine communities in the municipality of Itaituba in the State of Pará. Hair samples were collected for the determination of total mercury and the weekly frequency data of fish ingestion was recorded. The mean concentration of total mercury varied from 7.25μg/g (in 2013) to 10.80μg/g (in 2014), with no significant difference being observed (p = 0.1436). As for fish ingestion frequency, the majority of the individuals evaluated revealed high consumption both in 2013 and in 2014. High levels of total mercury were observed only in those with high consumption of fish in both years. The importance of ongoing monitoring of exposure levels in humans should be stressed, basing itself on indices of tolerance of 6μg/g recommended by the World Health Organization, and investigation about the consumption of fish such that strategies for control and prevention are improved.