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On-line version ISSN 1678-4596
COSTA, Claudia das Neves; MEURER, Egon José; BISSANI, Carlos Alberto and TEDESCO, Marino José. Sequential fractionation of cadmium and lead in soils. Cienc. Rural [online]. 2007, vol.37, n.5, pp. 1323-1328. ISSN 1678-4596. http://dx.doi.org/10.1590/S0103-84782007000500016.
The hazard environment impact and soil pollution by heavy metals should be evaluated not only by total concentration but mainly by their bioavailability because this property is better related with plant uptake. The objective of this experiment was to evaluate, trough sequential chemical extractions, the bioavailability of cadmium and lead in six soils of Rio Grande do Sul State, Brazil. The soil samples investigated come from a long term experiment in which 10 years ago three levels of Cd and Pb were applied (1.25, 2.50 and 5.0mg Cd and 250, 500, 1000mg Pb kg-1 soil). The sequential extractions detected differences among the adsorption forms of the two metals in the soils. The Cd was detected in all fractions, mainly in the exchangeable and organic, while Pb concentrated on the organic and residual fractions. The Cd presented larger mobility in soils, especially in those with smaller clay content; mobility of lead was very low in all soils.
Keywords : heavy metals; sequential chemical extractions; bioavailability.