Metals characterization in surface sediments of rivers in the Central Amazonian region

The evaluation of sediment quality is a relevant tool in environmental studies, being a dynamic processes influenced by weathering, soil runoff, atmospheric precipitation1,2. Amazon is one of the most relevant biome of the world, but due to its great extension area, almost there are not researches in the region of Itacoatiara, the third most populous city in the state. A total of 8 superficial sediments were collected, being 3 in White water rivers (WW)(Amazonas 1 and 2, Madeira), and others 5 samples in Black water rivers (BW) (Anebá, Carú 1 and 2, Urubu 1, 2 and 3), during the dry season. Sediments were collected using a Ekman-Birge grab according the protocols of sampling and preservation recommended (CETESB, 2011).4 Al, Cu, Zn, Pb, Ni, Fe, Cr e Cd were quantified by Flame or Graphite Furnace Atomic Absorption Spectrometer (240AA and 280Z, Varian) (USEPA, 1996). 5Metals were related to the guidelines of the Canadian Council of Ministers of the Environment as showed in Table 1.6 For all the sediments the results were below concentrations to Probable Effects Level (PEL) and Threshold Effects Levels (TEL), except for Cu. Overall, metal concentrations in sediments from WW samples (Madeira, Amazonas 1 and 2) were bigger than sediments from BW. Despite these rivers getnearestfromurbanareas, metals determination allowed to infer that all sediments sampled had values within the limits of the insurance for the maintenance of aquatic life in Central Amazonian.