SynopsisThe Clyde Estuary receives a relatively high pollutant load derived from the domestic and industrial wastes of half of Scotland's population. In order to monitor contaminant concentrations throughout the area, the Clyde River Purification Board (CRPB) initiated in 1980 an extensive ‘mussel-watch’ programme, having selected the common mussel as the most suitable indicator organism.This 1980 survey served not only to identify shores with elevated trace metal concentrations and those which were relatively unpolluted, but also to assess changes in overall contamination of the area in comparison with previous surveys.Following the success of the 1980 survey it has been gradually extended over the years, both in the number and geographical spread of sites visited, and in the substrates and determinands measured, as the CRPB's monitoring requirements have changed.The 1984 CRPB ‘mussel-watch’ survey involved the collection of over 1200 mussels at twenty-four sites throughout the Firth of Clyde (Fig. 1), with subsequent determination of concentrations of the trace metals Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn, and of other toxic, persistent substances such as organochlorine pesticides and PCB residues.Attention is focussed here on trace metal body burdens for Clyde mussels collected during the 1984survey.
