J. Phys. IV France
Trace metals inputs in the Adour urban estuary:
Influence and impact of human pressure
D. Point, G. Bareille, T. Stoichev, D. Amouroux and O.F.X. Donard
Laboratoire de Chimie Analytique Bio-Inorganique et Environnement,
UMR 5034 du CNRS-UPPA, Hélioparc Pau Pyrénées, 64053 Pau, France
Although the contamination of number of estuarine environments in the European Atlantic Coast has largely been studied [1-2],
the Adour urban estuary watershed (southwestern, France) is poorly known. The estuarine
part is characterized by an important anthropogenic pressure close to its mouth with large urban and industrial
activities of Bayonne city.
An environmental assessment program was funded to evatuate and quantify the anthropogenic pressure
ecosystem. A preliminary sampling strategy approach was adopted to identify 25 specific sources of contaminants,
monitored more extensively under four campaigns. Data treatment allows to trace effluent source and origin resulting in a
specific classification. Trace metal concentrations were determined (filtrate (
m) and particulate fractions) for each effluent and combined with discharge flow measurements to establish anthropogenic net
effluents presents the highest concentrations observed, followed by waste landfield drainage and sewage effluents.
The large variability in terms of effluent characteristics and concentrations observed, can be explained by strong
relationship between trace elements and both organic matter level (TOC) and flow rate.
This study point out the dominance
of upstream inputs compared to downstream localized sources, but their influence
into the estuarine ecosystem during low discharge conditions (summer) lead to a maximum metal impact
© EDP Sciences 2003