Human ecology of the riverine people (caboclos or ribeirinhos) along the upper Madeira River with focus on mercury pollution through fish consumption

Mercury (Hg) has been released into the Amazonian ecosystems as a result of gold mining activities. Organic Hg may be bioaccumulated up the aquatic food chain, of which humans are a top predator. The indigenous riverine population in the Amazon (caboclos or ribeirinhos) who rely on fish as their chief protein food source are therefore exposed to organic Hg, which is known to have neurotoxic effects on humans, especially during the prenatal and early postnatal development of the nervous system.; The interrelationship of gold mining and subsistence fishing are discussed within a broad range of related topics. The Brazilian context in which the gold mining had occurred is considered. From 297 household interviews the information on demography, including occupational activities, fertility, housing, health issues, are addressed for the study population. Also, Hg analysis in 577 fish samples and in hair samples from 550 individuals are presented. Fishing and agriculture are the major activities among the study population. A dietary questionnaire regarding food intake and fish consumption provided important information for the Hg exposure evaluation, which includes: 1) Estimate of Hg ingestion by the whole population (i.e., all age/gender sub-groups); (2) Risk assessment of Hg ingestion for the whole population; (3) Regression models to predict the infant hair Hg concentration; and (4) The native beliefs on fish consumption are compared to the fish Hg concentrations by species.; This dissertation provides a wide range of information within the contextual discussion of the study population regarding their use of the local environmental resources, including the potential consequences of critical levels of Hg exposure through fish consumption. A broader knowledge of the population is necessary to develop the further recommendations. A fish advisory through workshops and community organization is proposed to be carried out among the study population in order to address the current social needs and to prevent the potentially critical Hg exposure.