Validation of toxicity data and risk levels for soils: Progress report
Validatie toxiciteitsgegevens en risicogrenzen bodem: voortgangsrapportage 1995
van Beelen P, Notenboom J
RIVM Report 607505002
The progress of a research project on the field relevance of ecotoxicological laboratory tests has been described. The toxicity of zinc for several soil organisms is experimentally investigated at laboratory and semi-field conditions. Results are mutually compared with field observations along a gradient of metal contaminated soils, dominated by zinc. Several extraction techniques from soil chemistry (total, water, and CaCl2 extractions) are applied to investigate whether differences in zinc toxicity can be related to differences in the strength of metal binding to the solid phase. At this manner, however, an unequivocal correction for bioavailability between the different soils for the different organisms appeared not possible. This shows that risk assessment based on the content of extractable pollutants is not always better than risk assessment based on the total pollutant content. The differences between effect levels in laboratory tests and in the field for a particular species are relatively small when availability is assumed to be similar. This does not indicate that the premises used for the ecotoxicological risk assessment are falsified, but it emphasises the importance of a good correction for the availability of metals in different soils.