Water column variances in the aquatic environment, motivated by either natural or anthropogenic processes, may impact the stability of trace metals in the sediment of Santos Port Complex (SPC), located in southeast Brazil. Trace metals such as Cu, Zn, Ni, Pb, and Cd potentially negatively affect ecological and biological compartments in estuarine water. To evaluate the status of the sediment of the SPC, the present article investigated the geochemical fraction of sedimentary trace metals by applying the BCR (European Community Bureau of Reference) sequential extraction approach. Organic matter and fine grain size, characteristic of an estuarine environment, showed a direct influence on the concentration dynamics of trace metals in sediments, especially for Pb, Cd, and Ni. In the specific case of Zn and Cu, there was a potential source of contamination in the port. The largest fraction of the metals studied was non-residual, potentially mobilizable in an environment where variation in the physicochemical parameters of the water column is highly variable, something frequent in estuarine environments.
Keywords: trace metal speciation; Santos Harbor; sediment; environmental impact.