Mercury is a dangerous metal and an important source of environmental contamination in Brazil
and particularly in the Amazon. The main target organ of this metal is the CNS where it causes
damage that can lead to classic symptoms: ataxia, paresthesia, dysarthria, and changes in the
developing nervous system of children. The mercury contamination in the Amazonian rivers
increases the amount found in fish, especially those at the top of the food chain, exposing
people to mercury poisoning the rivers, since the fish is a central element in the diet of these
populations. Therefore, it is essential periodic monitoring of mercury levels in fish species
consumed in the region. Our study proposes to identify the levels of methylmercury and
inorganic mercury in fish species consumed by the riverside populations of the Tapajós region
and compare them with the levels found in the same species obtained in the region of Belém
also perform a comparison with results obtained by Dos Santos et al. (2000) and analyzing the
current level and the old. Fish were collected in the municipal market Itaituba, Tapajós, and
market the Ver-o-Peso in Belém. Muscle samples of each fish were dried and analyzed by the
Universidad de Castilla-La Mancha (Spain) for quantification of methylmercury and inorganic
mercury. The results obtained in this study showed that only piscivorous fish from the Tapajós
region have levels of methylmercury above the limit recommended by WHO (0.5 μg / g). All in
all study groups, levels of inorganic mercury are well below this limit. The species was the most
contaminated Brachyplatystoma flavicans (Dourada) and even to exceed five times the WHO
limit of tolerance. With our data, we can say that the fish of the Tapajós region are still currently
exposed to high concentrations of mercury. The non-fish-eating species had low concentrations
of organic mercury, is fit for human consumption. This study supports the importance of
continued monitoring of the environments considered exposed and not exposed in the Amazon.
Knowledge originated by this monitoring definitely foster the development of prevention
strategies and government actions before the problem of mercury contamination in the Amazon.
Keywords: inorganic mercury, methylmercury, fish, Tapajós, Belém
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