Perfil genotóxico e bioacumulação de metais em Hoplias malabaricus (Bloch, 1794) de tributários dos rios Negro e Solimões

Abstract

xi Abstract The presence of metals in the biot and water bodies is a cause of concern in animal and human health in the Amazon. Despite of the compounds input towards human activities on amazonian rivers, such as mining and urban pollution, their natural backgrounds are also known. Mercury, for example, is present in high concentrations on soil of the Rio Negro basin. Bioaccumulation of metals (Hg, Cu, Zn, Cr, Fe, Mn, Ni, Pb and Co) and genotoxic effects were evaluated in the amazonian species of carnivorous fish Hoplias malabaricus, an important food source for amazon “ribeirinha” communities. Fishes were evaluated in two basins with different limnological characteristics. Solimões-Amazonas River contains high levels of suspended solids, neutral pH and low concentrations of dissolved organic carbon. Rivers from Negro basin contains acidic pHs and high concentration of dissolved organic carbon due to the presence of humic substances. The concentrations of mercury (1 mg/kg) on fish muscle have been exceeded Brazilian law recommendation only in one sampling area from Negro river basin and the concentrations of chromium (0,1 mg/kg) on fish muscle have been exceeded Brazilian law recommendation only in two sampling areas fish from Solimões-Amazonas river basin. The Principal Component Analysis (PCA) showed environmental variables: pH, dissolved oxygen, temperature and electrical conductivity, influencing on bioaccumulation of metals and their genotoxic effects in Hoplias malabaricus. Fish from Rio Negro tributaries are more affected by genotoxic effects of metals than fish from Rio Solimões-Amazonas tributaries. Nevertheless the occurrence of micronucleus and nuclear abnormalities was observed in both basins, and where significantly higher on fish from Negro river compared to fish from Solimões-Amazonas river basin. ENA proved a better biomarker for black water besides MNs for white water. Therefore, since genotoxic damage are influenced by bioaccumulation of metals evaluated even at concentrations below the limits established as safe for fish consumption by ANVISA, the population who eats Hoplias malabaricus is predisposed to absorb accumulated contaminants in their their tissues and may be affected by the problems that affect them. This data can contribute to the discussion of the