Distribution and heavy metal pollution of the suspended particulate matter on the barcelona continental shelf (North-Western Mediterranean).

The distribution of heavy metal pollution associated with suspended particulate matter on the Barcelona continental shelf has been studied to evaluate the environment l impact of anthropogenic metals in this Mediterranean area. The main sources of heavy metal pollution on this continental shelf are the Besós River and the sewage sludge produced in the Barcelona-Besós wastewater treatment plant. The levels of Pb, Cr, Cu, Cd and Ni are very high around the mouths of the river and the pipeline of the wastewater treatment plant. The highest suspended sediment and heavy metal concentrations are along the inner and mid-shelf due to aggregation processes and the low energy of the dominant currents flowing in the study area. However, a significant amount of polluted suspended sediment is transferred to the slope by advective processes. This amount may be increased significantly by the action of wave-induced currents during strong storms. Trawl fishing may also contribute to the shelf-slope transfer of contaminated particles.