J. Phys. IV France 107 (2003) 1305
Heavy metals in six Brazilian watersheds: Levels of contamination in the state of São PauloA.C. Tomazelli1, 2 and L.A. Martinelli1
1 Centro de Energia Nuclear na Agricultura, USP, Av. Centenario 303, Caixa Postal 96, 13400-970 Piracicaba, Brazil
2 Faculdade de Filosofia Giências e Letras de Ribeirao Preto, USP, Brazil
The levels of Cd, Pb, and Hg were determined in bed sediments and suspended particulate material collected in six Brazilian watersheds (Alto Paranapanema, Peixe, Aguapeí, São José dos Dourados, Mogi-Gauçu, and Piracicaba) in the State of São Paulo (Southeast, Brazil), bimonthly from January to December, 2001. The levels of Cd and Pb in total and exchangeable fraction of the sediment were determined in the fraction lower than 63 by GFAAS. Cd and Pb in suspended particulate material were determined in the fraction lower than 0.45 m by GFAAS. The levels of Hg were determined by AFS. The levels of metals did not show temporal variability. Pb concentrations were low in all basins. Exchangeable Pb did not represent a significant fraction of the sediment. Cd concentrations were higher in the Piracicaba River basin, as a result from anthropogenic activities in the basin, such as industrial and domestic effluents damped in the river. Exchangeable Cd was up to 60% of the total Cd in the sediments. Hg concentrations were higher in the Peixe basin. All metals analyzed did not show high values, but the sources of Cd to the Piracicaba River and Hg to the Peixe River have to be evaluated.
© EDP Sciences 2003