J. Phys. IV France 107 (2003) 1049
Temporal evaluation of Cu, Mn, Pb and Zn potential mobilities in stream sediments of a copper mining area in South BrazilM.H.D. Pestana1 and M.L.L. Formoso2
1 Fundaçao Estadual de Proteçao Ambiental Henrique Luis Roessler, FEPAM, rua Carlos Chagas 55, 90030-020 Porto Alegre, Brazil
2 Centro de Estudos em Petrologia e Geoquimica (CPGq), Instituto de Geociências, Universidade Federal do Rio Grande do Sul, UFRGS, Av. Bento Gonçalves, CEP. 9500, 91509-000 Porto Alegre, Brazil
Sequential extractions were applied to the silt-clay fraction of stream sediments to evaluate temporal modifications on Cu, Mn, Pb and Zn potential mobilities, during different stages of copper mining activities, in September, 1993 and September, 1996. Cu and Pb partitioning, obtained flow a five-step extraction scheme showed the oxidizable `phase' as the most important for Cu and Pb, while the so-called carbonatic and the exchangeable `phases' were significant in the Zn and Mn partitionings. Cu presented the greatest variability between both, sites and sampling periods. The results suggest that metal partitioning, especially that of Cu, can be reflecting sulfide oxidation processes, probably enhanced by tailings exposure.
© EDP Sciences 2003