Riverine transfer of heavy metals from Patagonia to the southwestern Atlantic Ocean |
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Authors: | D Gaiero J Probst P Depetris L Lelyter S Kempe |
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Institution: | Centro de Investigaciones Geoquímicas y de Pocesos de la Superficie, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Avda. Vélez Sarsfield 299, 5000 Córdoba, Argentina, Laboratoire des Mécanismes de Tranferts en Géologie, UMR CNRS/Université Paul Sabatier no?5563, 38, rue des 36 Ponts, 31400 Toulouse, France, Equipe de Recherche en Physico-Chimie et Biotechnologies, Université de Caen, Bd. du Marechal Juin, 14032 Caen, France, Geologisch-Pal?ontologisches Institut, Technische Universit?t Darmstadt, Schnittspahnstrasse 9, Darmstadt 64287, Germany,
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Abstract: | The occurrence and geochemical behaviour of Fe, Mn, Pb, Cu, Ni, Cr, Zn and Co are studied in riverine detrital materials
transported by Patagonian rivers. Their riverine inputs have been estimated and the nature of these inputs to the Atlantic
Ocean is discussed. Most of the metals are transported to the ocean via the suspended load; there is evidence that Fe oxides
and organic matter are important phases controlling their distribution in the detrital non-residual fraction. Most heavy metal
concentrations found in bed sediments, in suspended matter, and in the dissolved load of Patagonian rivers were comparable
to those reported for non-polluted rivers. There is indication that human activity is altering riverine metal inputs to the
ocean. In the northern basins – and indicating anthropogenic effects – heavy metals distribution in the suspended load is
very different from that found in bed sediments. The use of pesticides in the Negro River valley seems correlated with increased
riverine input of Cu, mostly bound to the suspended load. The Deseado and Chico Rivers exhibit increased specific yield of
metals as a consequence of extended erosion within their respective basins. The Santa Cruz is the drainage basin least affected
by human activity and its metal-exporting capacity should be taken as an example of a relatively unaffected large hydrological
system. In contrast, coal mining modifies the transport pattern of heavy metals in the Gallegos River, inasmuch as they are
exported to the coastal zone mainly as dissolved load.
Electronic Publication |
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Keywords: | Heavy metals Riverine inputs Suspended particulate matter Bed sediments Patagonia |
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