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Heavy Metal Dispersion from Industrial Wastes in the Vale Do Aço, Minas Gerais, Brazil

1996; Taylor & Francis; Volume: 17; Issue: 5 Linguagem: Inglês

10.1080/09593330.1996.9618369

1479-487X

Cláudio Pereira Jordão, Julião Pereira, Walter Brune, J. L. Pereira, P. C. Braathen,

Heavy metals in environment

The Vale do Aço (literally ‘Steel Valley’) represents one of Brazil's most outstanding smelting resources. The Vale do Aço lies located between two confluent rivers which jointly constitute, by their tributary streams, the water supply of its half a million inhabitants. The smelting of the ores may well be harmful to people in the way of slow but chronic poisoning. No reliable figures are available for iron nor for trace metal occurrences in water, neither for natural waters nor for water treated for potable purposes. Thus, with the purpose of establishing a preliminary report to trace out industrialisation outcomes, samples of potable and river waters, soil, sediment, plant and fish were taken at nine sites up- and down-river with respect to the most important smelteries. Samples gathered at the middle of the rainy and dry seasons were analysed to detect metal dispersions. Samples from a fountainhead as well as from a dam were also investigated to obtain regional background values. The concentration of the metals Fe, Al, Mn, Cr, Cd, Pb, Cu, Zn, Co, Ni, Mg, Ca and Mo was measured in these samples by atomic absorption spectrophotometry, while Na and K were determined by flame photometry. High concentrations of Fe, Al, Mn, and Zn were found in river waters, while potable water showed no substantial contamination. The sediments were contaminated with Cr, Cd and Mn. The heaviest contamination of sediments was generally observed in the dry season, probably as a consequence of the fact that smaller water volumes obviously tend to exhibit higher concentrations of pollutants. Most of the metals found in the soil samples showed higher concentration in the rainy season than in the dry season. The Cd, Cr and Pb were found at higher levels in the analysed plant than in those normally observed in vegetables. The Cr concentration in fish exceeded 50 times the Brazilian recommendation value for human intake.