TR 086 – Derivation of Assessment Factors for Human Health Risk Assessment


TR 086 : Derivation of Assessment Factors for Human Health Risk Assessment | February 2003

In general, the risks to human health posed by chemical substances are assessed by the extrapolation of heterogeneous animal data to man. In this report, the extrapolation elements used in the process are reviewed. These include the establishment of the appropriate ‘no observed adverse effect level’ (NOAEL) for the critical effect, the difference in exposure duration between the experimental data and the assumed lifetime exposure for humans, the route to route extrapolation when the route of exposure is different for humans and the consideration of differences in sensitivity of response both between species (interspecies) and within a species (intraspecies).

For cases in which appropriate substance-specific information is lacking, guidance is provided for the derivation of plausible numerical values to account for the uncertainties and variabilities in defining a ‘safe dose’ for man. The default assessment factors recommended are considered to be justifiable, based on current science and transparent assumptions; they are provided as useful ‘interim guides’ in the risk assessment process.

The factors replace those proposed in ECETOC Technical Report 68, and are intended to be used with the guidance provided, and only in the absence of appropriate substance-specific information. In cases where no default assessment factors are proposed, guidance is given on the type of additional information needed for the particular element of extrapolation.

The approach proposed in this report is particularly useful for general industrial chemicals, where detailed toxicological studies are not always available or easily conducted.

Professional expert judgement should be applied when using the recommended approach and the related guidance.