Trophic structure and mercury biomagnification in tropical fish assemblages, Iténez River, Bolivia.

We examined mercury concentrations in three fish assemblages to estimate biomagnification rates in the Iténez main river, affected by anthropogenic activities, and two unperturbed rivers from the Iténez basin, Bolivian Amazon. Rivers presented low to moderate water mercury concentrations (from 1.25 ng L(-1) to 2.

Mercury bioaccumulation patterns in fish from the Iténez river basin, Bolivian Amazon.

The bioaccumulation mechanism expresses an increment of mercury concentration along the lifetime of each individual. It is generally investigated along the age or size range of organisms from a same population. Water chemistry and trophic position are important factors that may influence the emergence of bioaccumulation patterns.

Hydroelectric reservoir inundation (Rio Madeira Basin, Amazon) and changes in traditional lifestyle: impact on growth and neurodevelopment of pre-school children.

Objective: To assess the dependence on fish consumption of families and its impact on nutritional status and neurodevelopment of pre-school children.

Design: Cross-sectional study that measured children's hair mercury (HHg) as an indicator of family fish consumption, growth (anthropometric Z-scores, WHO standards) and neurological (Gesell developmental scores (GDS)) development.

Setting: Traditional living conditions among families residing in the area adjacent to the Samuel Dam (Western Amazon) hydroelectric reservoir.

Transfer of mercury and methylmercury along macroinvertebrate food chains in a floodplain lake of the Beni River, Bolivian Amazonia.

We have evaluated the mercury and methylmercury transfers to and within the macroinvertebrate communities of a floodplain lake of the Beni River basin, Bolivia, during three hydrological seasons and in two habitats (open water and vegetation belt). Using the stable isotopes delta(13)C and delta(15)N, six trophic chains were identified during a previous study. Four are based on only one source: seston, organic matter from the bottom sediment, periphyton and macrophytes.

Elevated blood lead levels in a riverside population in the Brazilian Amazon.

Lead (Pb) is recognized as one of the most toxic metals. Sources of Pb exposure have been widely documented in North America, and the removal of Pb additives from gasoline was reflected in a dramatic lowering of blood Pb concentration. In Latin America, the removal of Pb from gasoline resulted in decreased exposure, but Pb levels in many areas remain high due to occupational and environmental sources of exposure.