Ingestion of fish is considered the main pathway of human exposure to methylmercury (MeHg), particularly for riverside populations, where fish is the main source of protein. The objective of this study was to estimate concentration of MeHg based on total concentration of mercury in muscles of three species of carnivorous fish: Boulengerella cuvieri (bicuda), Serrasalmus rhombeus (piranha), and Hydrolycus armatus (cachorra), collected from Teles Pires River, Brazil. Furthermore, we calculated human health risk related to MeHg contamination caused by fish consumption. Fish were collected in 20 field campaigns from December 2011 to September 2016 at Teles Pires River, in area of influence of Colíder hydroelectric plant. Risk index (RI) related to ingestion of MeHg through fish intake was calculated considering that MeHg corresponds to around 90% of mercury in fish. There were no significant differences in average mercury concentration between all species: S. rhombeus (0.304 mg/kg^–1), H. armatus (0.229 mg/kg^–1), and B. cuvieri (0.199 mg/kg^–1). RI calculated for sensitive groups (lactating women, breastfeeding infants and children) and RI calculated for general population presented average values, suggesting adverse health effects. This first assessment on MeHg and human exposure to people from Teles Pires River area through fish consumption suggests that mercury concentrations might be posing health adverse effects on people of this sensitive group. Further studies involving more fish specimens and considering fish biological factors are needed to fully understand health risks of mercury exposure to humans in this region.

The composition of the diet of two species of characids (Knodus heteresthes and Moenkhausia lepidura) was evaluated in the Teles Pires and Juruena Rivers, sampled in September and October 2016. We analyzed 226 stomachs of K. heteresthes and 425 of M. lepidura. The analysis of the stomach contents was based on volumetric and frequency of occurrence methods, applying the food importance index. For the similarity of the diets between the species we calculated the niche overlap with Pianka’s index. Both species in the Juruena River have a dietary preference for arthropods (IAi > 0.95). In the Teles Pires River the diet is concentrated in three sources for both species: arthropods (IAi > 0.52), vegetables (IAi > 0.33) and fish (IAi > 0.12). The diet was dissimilar when compared to environments (ANOSIM, R ≥ 0.57, p < 0.001) with high trophic niche overlap (α > 0.97), regardless of the sampled environment. In the Teles Pires River, both species were classified as omnivorous with an insectivorous tendency and in the Juruena River the insectivorous behaviour occurs.

A região Centro-Oeste do Brasil apresenta uma contribuição substancial para a produção agrícola nacional, o que implica também grande consumo de agrotóxicos. Objetivou-se neste estudo analisar a dinâmica das vendas de agrotóxicos em território nacional através de uma série de oito anos (2009 a 2017), com ênfase nos Estados de Mato Grosso e Goiás. Obteve-se os dados de área plantada de lavouras permanentes e temporárias, e vendas de agrotóxicos para Brasil, Mato Grosso e Goiás, tratando-se de um estudo epidemiológico do tipo ecológico. Dessa forma, esse estudo apresenta a espacialização da área plantada por hectares nos municípios brasileiros e o consumo de agrotóxico observando uma expansão crescente nestas séries históricas. Os resultados mostraram nestes oito anos (2009 a 2017) que Brasil, Mato Grosso e Goiás tiveram um aumento ano após ano de área, equiparado à venda. A partir dos dados de venda de agrotóxicos, pode-se inferir o avanço do agronegócio o que pode ser minimizado nesses municípios brasileiros estabelecendo estratégias de prevenção para diminuir danos causados pelos agrotóxicos.