Guidance document on the derivation of maximum permissible risk levels for human intake of soil contaminants

This report contains a basic step-to-step description of the procedure followed in the derivation of the human-toxicological Maximum Permissible Risk (MPR ; in Dutch: Maximum Toelaatbaar Risico, MTR) for soil contaminants. In recent years this method has been applied for a large number of compounds (the results have been published as separate RIVM reports). In the report the different steps in the procedure are discussed briefly and an outline of the kind of problems to be dealt with, is provided. General issues of regulatory risk assessment aimed at the derivation of health-based limit values are addressed and reference is made to some basic background literature. Overall, the approach for MPR-derivation as described here, is a pragmatic one in that use is made of existing toxicological evaluations by national and international bodies. Thus, it is attempted to avoid unwanted duplication of effort. In case no adequate review was available for a particular compound, a complete literature search for original publications is done. The results, however, were used selectively. The MPR-derivation as a whole proceeds in a structured manner, it is nevertheless stressed throughout the report that, unavoidably, for an adequate evaluation of the data on the different toxicological endpoints some professional judgement is needed