A proposed method for calculating taxonomic-group-specific variances for use in ecological risk assessment

A method for calculating variances for toxicological parameters, in particular, for LCS0-values is presented as one possible increment of risk assessment. It is based on the statistical analysis of several substance-specific data subsets containing at least 3 data per chemical for the taxonomic group of interest. When analyzing homogeneous data, i. e. substance-specific data generated in the same laboratory, respectively, for the class of Osteichthyes a mean variance value of 0.12 log units was found whereas analysis of interlab data yielded a value of 0.23. Extending these studies to freshwater invertebrates resulted in a much greater variance value, namely approx. 0.5.