Determination of source concentrations of dissolved and particulate trace metals in the Southern North Sea

During the NERC North Sea Project, concentrations of dissolved and particulate Cd, Cu, Pb, Ni and Zn, together with suspended particulate matter (SPM), were determined at over 100 locations on each of four survey cruises. In an earlier study, McManus & Prandle (1994) described an inverse modelling technique to derive source concentrations. The inclusion of an SPM routine in this model (McManus & Prandle, submitted), and the use of partitioning coefficients (KD) means that this technique can now be used to determine source concentrations for particulate metals, as well as to refine the earlier dissolved estimates. These derived dissolved and particulate source concentrations are shown to be in fairly good agreement with values cited in the 1993 Quality Status Report (QSR; North Sea Task Force and International Council for the Exploration of the Sea, 1993). Moreover, the discrepancy in the earlier study between the 1987 QSR and model distributions for Pb (due to the neglect of scavenging by particulate material) is now resolved (International Conference on the Protection of the North Sea, 1987).