THE NEED FOR ADEQUATE BIOLOGICAL SAMPLING IN ECOTOXICOLOGICAL INVESTIGATIONS - A RETROSPECTIVE STUDY OF 20 YEARS POLLUTION MONITORING

The measurement of concentrations of persistent bioaccumulating chemicals in ecological samples is an important tool in ecotoxicological science. It is important to consider the need for both chemical and biological precision when designing research programmes for studying enviromental pollution. The balance between chemical and biological precision is discussed on the basis of a database from the Swedish Contaminant Programme covering the period 1969-1989. The negative consequences of the analysis of pooled samples instead of individual specimens are demonstrated. The importance of various biological parameters such as sampling sites, content of fat and age of the specimens analyzed is shown. The prerequisite of a sufficiently long lime-span and frequency of sampling in monitoring studies is shown.