Environmental specimen banking. Herring gull eggs and breams as bioindicators for monitoring long-term and spatial trends of chlorinated hydrocarbons

The German Environmental Specimen Bank (GESB) has been an important tool in contaminant monitoring and ecotoxicological research for more than one decade. The annual monitoring program provides a long-term database to determine trends in contaminant burdens in biota samples. Results of ten years of experience in the determination of chlorinated hydrocarbons (CHCs) in herring gull eggs collected in the North Sea and the Baltic Sea are presented. In addition, the study reports CHC concentrations in bream livers from the River Elbe between 1993-1997. Most of the compounds studied show a significant decline over time, especially in samples from East Germany. For specimens taken in West Germany, only small decreases or no changes of CHC levels were observed.