Distribution of heavy metals in environmental samples near smelters and mining areas in Brazil

The State of Minas Gerais possesses one of Brazil's important smelting reso urces. Aquatic contamination produced from mining activities and smelting o f ores in the region may be harmful to the human population. However, no st udies on levels of heavy metal have been carried out in the area. Thus, to assess the extent of pollution resulting from the metalliferous industry, r iver water, sediment, plant and fish samples were collected up and down-riv er from the smelters and mining areas in Conselheiro Lafaiete and Ouro Bran co and analysed to detect metal inputs. Samples of mineralized, contaminate d and non-contaminated regions were also collected in the State of Minas Ge rais to obtain control values. The metals examined included Fe, Al, Mn, Pb, Cu, Zn, Co, Cd, Ni, and Cr and were selected due to their toxicity and occ urence in ores. Metal inputs in the samples analysed appeared to be related to effluent discharges into the rivers. High concentrations (in mu g l(-1) ) of Mn (697), Fb (153) and Cd (12.7) were found in river water collected f rom the smelting region when compared with control areas. The river sedimen ts showed high concentrations (in mu g g(-1)) of Mn (32276), Cd (1.4), Cu ( 70.6), Ni (170), and Cr (174). The concentrations of Mn and Cr in the plant s were higher than those normally found in these materials. Chromium concen tration in fish was found to be five times higher than the Brazilian recomm ended value for human intake.