4 research outputs found
Coprostanol levels and organic enrichment in sediments of the Bilbao estuary (north of Spain)
An assessment was made of the distribution of the faecal sterol coprostanol (COP) in sediments in the Bilbao estuary. Concentrations of COP ranged from 135.15 to 10.77 mu g g(-1) dry weight, from the inner to the open estuary, with a mean value of 51.43 mu g g(-1); the highest concentrations were found near the mouths of several tributaries flowing into the estuary. Comparisons with ether published values indicate that sediments from the Bilbao estuary are affected by sewage pollution in a similar degree to that reported for other estuaries in the world. Organic enrichment and anaerobic sediment conditions prevail in three-fourths of its watercourse bed. Since the spatial distribution of several organic sedimentary parameters could be clearly correlated with COP levels, we can conclude the existence of major pollution by the addition of untreated sewage, coming from mainly domestic sources. The implementation of a sewerage treatment plan by the local water authority needs the monitoring of reliable sewage tracers, such as faecal sterols, to assess the effectiveness of the plan in reducing the effects of pollution.La rĂ©partition du stĂ©rol fĂ©cal coprostanol (COP) a Ă©tĂ©Ă©valuĂ©e dans les sĂ©diments de l'estuaire de Bilbao. Les concentrations en COP dĂ©croissent de 135,15 Ă 10,77 ÎŒg gâ1 de poids sec, de l'intĂ©rieur vers le large, avec une valeur moyenne de 51,43 ÎŒg gâ1, les valeurs les plus Ă©levĂ©es Ă©tant trouvĂ©es Ă l'embouchure de plusieurs affluents. La comparaison avec d'autres rĂ©sultats publiĂ©s indique que les sĂ©diments de l'estuaire de Bilbao sont atteints par la pollution des Ă©goĂ»ts Ă un niveau comparable Ă celui d'autres estuaires dans le monde. L'enrichissement organique et les conditions anaĂ©robiques rĂšgnent sur les Full-size image (<1 K) du lit du cours d'eau. Comme la rĂ©partition spatiale de plusieurs paramĂštres de la sĂ©dimentation organique est corrĂ©lĂ©e aux niveaux de COP, on peut conclure Ă une pollution majeure par des rejets non traitĂ©s, provenant principalement de sources domestiques. La rĂ©alisation d'un plan de traitement des rejets par l' âAutoritĂ© de l'Eauâ locale exige le suivi de traceurs pertinents, comme les stĂ©rols fĂ©caux, pour apprĂ©cier l'efficacitĂ© du plan sur la rĂ©duction de la pollution