The rol of Bahia Blanca estuarine sediments for trapping and accumulation of heavy metals

MARCOVECCHIO, J.E.; FERRER, L.; BOTTÉ, S.E.

Mar del Plata

Congreso; 2001: AN OCEAN ODISSEY. JOINT ASSEMBLIES OF THE IAPSO-IABO; 2001

IAPSO-IABO

Bahía Blanca is a large estuarine environment located within the south littoral of Buenos Aires Province. Water interchange within the bay is influenced by a semi diurnal tidal regime, and the hydrography of the estuary is strongly influenced by climatic conditions. Several streams and channels flow into the bay, most of them affected by anthropic activities. This estuary is extensively used by fishing boats, oil tankers and cargo vessels, requiring regular dredging. Moreover, this coastal marine system receives contaminant inputs from municipal waste-waters, direct industrial discharges, harbour related operations, runoff water which carries materials from land development areas and aerial fallout from atmospheric pollutants. The above mentioned has supported the development of along-term study programme for the evaluation of heavy metals occurrence, concentration and distribution in the estuarine sediments, as well as their corresponding geochemical partitioning in the less than 63µ grain size fraction of the sediment. Total concentrations of heavy metals (Cd, Zn, Cu, Cr, Pb) have been determined through flameless AAS, while the geochemical partitioning of these metals has been studied by the same way but after a sequential extraction system. The obtained results have allowed to characterize spatial distribution of the evaluated metals, as well as to identify their accumulation areas and potential sources. Moreover, a theoretical scheme of transference of these metals to other compartments within the system was proposed. Finally, the environmental status of the estuary was addressed within the described framework