TRACE-METALS IN FISH USED FOR TIME TREND ANALYSIS AND AS ENVIRONMENTAL INDICATORS

A series of regressive models described in the ICES guide-lines for the time-trend investigation in levels of contaminants in fish, has been tested and evaluated on the basis of 11 years of monitoring data. Metal concentrations (Cd, Cu, Hg, Pb, and Zn) in plaice (Pleuronectes platessa) from three stations along the Jutland coast of the North Sea and concentrations in flounder (Platichthys flesus) from one station in the Sound and the Great Belt, respectively, have been used. A new graphic method that facilitates the statistical understanding has been developed. Time trends analysis showed a recent decrease in Pb concentrations, while the yearly variation among the rest of the concentrations was high. The largest Hg concentrations were found in the Sound. The differences in concentrations between species were small, except for Cu. An environmental index that incorporates all trace metal concentrations in the fish is suggested and problem areas are pinpointed.