The Reference-Matrix Concept Applied to Chemical Testing of Soils

The concepts and philosophy on the use of reference matrices, which had been developed within an IUPAC Project on reference soils, are developed and exemplified on the example of soils. These reference matrices are intended for the assessment of extrinsic properties of chemicals. It is shown how, reference matrices together with well-established reference substances are forming a harmonised testing system, which allows extrapolating laboratory findings via the use of appropriate models to real processes defining the pathways and fate of environmental chemicals. Thus, well-defined reference matrices offer interesting perspectives of increasing environmental realism in chemical risk assessment. Given the increasing globalisation and given the implementation of new legislation in various countries, most notably in Europe (new chemical regulation � REACH -, Water Framework Directive and the newly established Soil Framework Directive), there is an even greater need for having available well-defined reference matrices. This need goes along with the need to test the environmental fate and effects also new materials such as artificially nanoparticles. It is therefore to be foreseen that apart from terrestrial reference matrices, guidance on additional reference matrices like sediment and even biological materials is an issue for further research. The concept outlined in this contribution provides suitable guidelines for selecting such matrices. It is to be noted, however, that agreement on the optimal application of reference matrices and the interpretation of the results obtained in tests using reference materials, needs to be obtained between scientists, risk assessors, reference laboratories and international standardization organisations.

JRC.H.5 - Rural, water and ecosystem resources