Comparison and Characterization of OECD Artificial Soils

Abstract

OECD artificial soil is a widely used substrate in soil toxicity tests. Despite its apparent necessity as a defined mixture relevant for solid phase exposure, several problematic issues have been revealed recently which must be considered seriously. It is not clear if the OECD artificial soil is really a standardized reference material omitting the influences of varying natural soil properties or if there is still significant variability present, which may influence toxicity results. Under the auspices of the EU ringtest for the ecotoxicity of wastes, a new project has been started with the aim of addressing the variability of nearly 20 artificial soils. Although the collected soils were declared to have been prepared strictly according to OECD guidelines, they were different even at the first look and the organic carbon content in the artificial soils varied from 1.4 to 6.0%. This indicates the variability in the organic carbon content of peat from different sources, producers and countries. The cadmium sorption experiment on selected soils suggests that the cadmium K d varies among artificial soils over one order of magnitude. It is apparent from our pilot results that there are differences between the OECD artificial soils from various labs in the EU.