The common mussel Mytilus edulis as an indicator of trace metals in Scandinavian waters. I. Zinc and cadmium

Abstract

Concentrations of zinc and cadmium in whole soft parts of mussels, Mytilus edulis (L.), collected from 54 locations in Scandinavian waters were determined. Local variations in concentrations of the two metals found in samples taken close to industrial sources of zinc and cadmium confirmed the ability of the mussel to act as an accurate indicator of pollution by these metals over the entire range of salinities in which this species can exist. In addition, offshore samples remote from industrial discharges revealed higher concentrations of zinc and cadmium in mussels from lowsalinity areas (Gulf of Finland, Southern Bothnian Sea, Baltic proper) than in those from high-salinity areas (Kattegat, Eastern Skagerrak). Major decreases in metal concentrations present in the mussel were apparent in the regions of the Sound and the Great Belt, which are areas of rapid salinity change due to mixing of Baltic water with water from Kattegat. Comparison of these results with those reported for zinc and cadmium in water throughout the study area suggested the existence of a higher biological availability of these metals in regions of low salinity; possible reasons for this are discussed. Data from the present survey are also compared to those reported for mussels taken elsewhere. This comparison reveals the Baltic area to be considerably polluted by trace metals; in contrast, the waters of Kattegat and skagerrak are considered to be relatively unpolluted.