DOI: http://dx.doi.org/10.1065/jss2004.08.110
Goal, Scope and Background. In terrestrial ecotoxicology, standardised test methods using plants, earthworms and insects are available for the evaluation of effects induced by heavy metals, organic chemicals and, in particular, pesticides. Currently, these tests are performed either by using so-called Artificial Soils or (more or less) arbitrarily selected natural soils. Consequently, the test results depend not only on the intrinsic physico-chemical properties of the test chemical, but are also significantly influenced by the variable properties of the chosen soil. In order to standardise the test conditions and, at the same time, to relate the test results to representative soil types within the EU, it is proposed to modify the EURO-Soil concept for testing purposes.
Main Features. The EURO-Soil concept, i.e. the selection of a limited number of soils that are representative for Europe, was originally developed for the performance of standardised environmental fate tests. Despite many problems in detail, soils from six sites all over Europe were identified that cover a wide range of soil properties (e.g. texture, pH, organic matter content) and, therefore, very different conditions concerning the bioavailability and, in turn, the effects of chemicals. Obviously, the routine use of EURO-Soils as a control or test substrate would require large amounts of soil. Therefore, it is proposed to modify this concept in such a way that all soils similar to one of the six EURO-Soils can be used for ecotoxicological tests.
Results and Discussion. It is assumed that the six EURO-Soils are representative for wide areas of the European Union, but at the same time it is neglected that some soils typical for, e.g. Northern Scandinavia, have to be identified in the future. All soils having similar properties (i.e. texture, pH, C/N ratio, and organic matter content) as one of the original EURO-Soils are called SIM-Soils. In this contribution, "ranges" are proposed for four main properties and the six EURO-Soils, thus allowing the identification of the SIM-Soils. However, since these properties cover a continuum, soils cannot be classified easily into a small number of classes; expert knowledge is required in order to decide whether a natural soil belongs to a certain SIM-Soil class or not. In the long run, this classification must take biological parameters like their suitability for standard test organisms into account as well.
Recommendation and Outlook. The soils selected so far (at least one for each EURO-Soil) are actually tested using different biological test methods. Further tests are necessary in order to decide which tests can be done in which soil and whether new test systems, e.g. covering acid soils, have to be developed. However, it is already clear that the standard test species differ distinctly regarding their sensitivity towards soil properties. It is recommended to use the SIM-Soils in order to provide the authorities with more field-relevant data when assessing chemicals in the terrestrial environment. |
