PARTITIONING OF METALS IN SEDIMENTS FROM THE LOWER PARAÍBA DO SUL RIVER, SE, BRAZIL

Abstract

This investigation aims to determine the extent of heavy metal dispersal from the heavilyindustrialized middle river segment of the Paraiba do Sul River to the lower stretch of the river and estuary. This analysis was carried out in sediments from river channel, floodplain and estuary of the lower river basin by using total and slightly modified BCR sequential extraction procedures. Overall, the lower river basin shows smaller metal concentrations than industrialized river segment. For Cu, Cr, Ni the small spatial variation of total metal distribution and predominance of residual phase suggests reduced influence from middle river basin and distribution of such metals along the lower river basin controlled by local sources such as soil particles erosion. In contrast, the decay pattern observed as distance increased from the middle river basin for Cd, Pb, and Zn suggests that the metal dispersion from the middle river segment is reaching the lower stretch of the river. These metals are associated with reactive forms, which are environmentally significant with respect to chemical mobilization and ecotoxicology.