English Abstract Purpose of this study was the validation of several
effect assessment extrapolation procedures with toxicity data derived from
experiments in more complex aquatic systems. A second goal was the
comparison of the results of multiple species-experiments with toxicity data
of single species-experiments for related species. With restrictions, due
to paucity of data, it is concluded that single species toxicity data are a
good starting point for establishing 'safe' concentrations for the aquatic
ecosystem. Furthermore extrapolation procedures seem to be a good basis for
establishing these 'safe' concentrations if sufficient toxicity data are
available for sensitive taxonomic groups. From the results of this study it
was not possible to prefer one of the validated extrapolation
procedures.
