CONICET | Buscador de Institutos y Recursos Humanos

Estuaries usually behave as a geochemical trap for dissolved materials, firstly increasing their concentration and eventually transferring them to cohesive sediments through different processes. Many anthropogenic pollutants are associated to clay minerals, or have at least a similar dynamical behavior. Such reasons sustain the fact that potentially dangerous substances (including heavy metals) spread out to be concentrated in those places where low environmental energy allows fine sediment to settle as tidal flats and artificial mooring sites.Bahía Blanca estuary presents good chances for man-activity introduction of pollutants into the environment, as it includes the most important artificial deep harbor system within Argentina, as well as industrial nucleous and large cities. Once these substances are deposited, no negative consequences on the environment are produced because immobilization. However, the Bahía Blanca Estuary mooring sites are periodically dredged by water injection (ca. 400,000 m3/yr), potentially promoting the transference of those originally immobilized substances to bioavailable compounds, and so its dissemination through the environment. To determine the concentration of potentially dangerous elements which naturally occur on sediments within the environment is necessary in order to be able to assess the man-originated chemical pollution degree on materials which are being dredged. In this study these values were determined by analyses of a total of 32 sediment samples (Fig. 1) from a functional tidal flat from a southern island and from non-functional tidal flats deposited between 3500 and 3300 years ago and samples from or close to the potential pollutant input (mooring sites, sewage and industrial outfalls).

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