Validatie van risicogrenzen voor de bodem. Verslag van een workshop gericht op de opzet van een onderzoekprogramma

A workshop was organized June 10th last by the RIVM and the Directorate-General of Environmental Protection (Ministry of Housing, Physical Planning and Environment) on validation of ecotoxicological derived risk levels for soil ecosystems. The intention of the workschop was to give priorities and to discuss methodological and theoretical possibilities for a research program directed to the validation of risk levels. Several short introductions were given by policy makers and scientists. These introductions are included in this report as separate chapters (2,3,4 and 5). An account of the discussion is given in chapter 6. Reactions received later are incorporated as chapter 7. Conclusions and suggestions are formulated by the organizers of the workshop and presented in chapter 8. The actual procedure used by the ministry for deriving standards for substances in the environment was taken as a departure for discussion. Three aspects to be proved were recognized in this procedure. (1) Field relevance of toxicity data derived in laboratory single species tests. (2) Validation of the assumptions underlying the methodology used for deriving risk levels. (3) Consequences for the ecosystem when the NOEC values for 5 or 50% of the species are exceeded. At short notice validation of all these aspects is unreliable. Since the first aspect was considered as the most basic in the context of the actual procedure and critical for the entire procedure it was advised to direct the limited research potential to this aspect.