GEOCHEMICAL CONTROL OF HEAVY METAL CONCENTRATIONS AND DISTRIBUTION WITHIN BAHIA BLANCA ESTUARY (ARGENTINA)

MARCOVECCHIO, J.E; BOTTÉ, S.E.; FERNÁNDEZ SEVERINI, M.D.; DELUCCHI, F.

Aquatic Geochemistry

Springer Netherlands

Lugar: Published online: 6 November 2009; Año: 2009 vol. 16 p. 251 - 266

1573-1421

Chromium and lead concentrations and distribution have been fully studied within Bahía Blanca estuary inner area, which is strongly influenced by urban and industrial stress. Not only metals dissolved in estuarine water but also those included in sediments and suspended particulate matters (SPM) were measured. In all cases, internationally standardized protocols were applied to metal measurements, including analytical quality check test through analysis of certified reference materials.Total metal contents from surface sediments and SPM were compared with those from a historical database of the area, as well as with values representing the natural geochemical baseline within the system. Results showed that heavy metal pollution is mainly localized in the areas both close to the industrial effluents discharge system and to the urban sewage outfall discharge. Data from sequential extractions indicate that metals from anthropogenic sources(i.e. Pb) are potentially more mobile than those inherited from geological parent material (i.e. Cr). The influences of other potential sources of metals (i.e. streams, runoff) were also considered.Heavy metals adsorbed to SPM were particularly examined considering the influence of this process on both bioavailability and toxicity of trace metals in natural waters.Finally, the normalization of measured metal concentrations against background reference elements (i.e. Al or Fe) has allowed identifying the lithogenic or the anthropogenic origin of these pollutants within Bahía Blanca estuary.