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Titre :
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Trace metals in the Westerschelde estuary: a case-study of a polluted, partially anoxic estuary
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Auteurs :
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W. Baeyens
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Type de document :
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article/chapitre/communication
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Année de publication :
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1997
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Format :
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167 p.
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Note générale :
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Diffusion tous publics
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Langues:
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= Anglais
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Catégories :
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POLLUTION DE L'EAU
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Mots-clés:
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SCHELDT ESTUAIRE
;
ESTUAIRE
;
TRACE
;
METAUX
;
ETUDE D'ENVIRONNEMENT
;
MODELE
;
TOXICITE
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Résumé :
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Four aspects make the Scheldt estuary very particular and different from other estuaries: - the Schldt is a tide-governed estuary, which means greater residence times; - the upper estuary receives larges inputs of biodegradable organic matter which leads to oxygen depletion in winter and to anoxic conditions in summer; - inputs of toxic pollutants from the industrial zone of Antwerp occur in th upper estuary; - the anoxic zone, the zone of pollutant input and the zone of the turbidity maximum coincide geographically. The Scheldt estuary is therefore an ideal field laboratory for the study of biogeochimical processes which do not occur elsewhere, or occur only partially, to a very slight extent or in a specific compartment such as the sediments. More specifically, redox processes involving trace metals, the formation of non-labile metal complexe or the methylation of mercury occur as a result of anoxic conditions and the high load of organic matter. Several models describing in detail the transport, sedimentation and speciation of the trace metals in this well-mixed estuary (all major estuaries in EC countries adjacent to the North Sea or the Atlantic Ocean are well-mixed) are presented in this volume. A comparison of the metal concentrations over a 15-year period shows a net reduction in the pollution level.
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Source :
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Hydrobiologia, vol. 366, n° 8
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