ANTHROPOGENIC HEAVY-METAL POLLUTION IN THE SEDIMENTS OF THE BARCELONA CONTINENTAL-SHELF (NORTHWESTERN MEDITERRANEAN)

The surface sediments of the Barcelona continental shelf are greatly affected by anthropogenic contamination of heavy metals discharged by the littoral sewers and the Besos River. This pollution affects mainly the sediment of the inner Besos prodelta, decreasing gradually southward and more sharply seaward from the river and sewer mouths. In the outer part of the prodelta heavy metal pollution is relatively low, except in the area where the waste discharged through the pipeline of the Barcelona-Besos wastewater treatment plant accumulates. This waste produces a strong metal anomaly with a sharp bordering gradient. The relict sandy sediment of the outer part of the shelf is hardly affected by heavy metal pollution.