Soil Screening Values (SVs) are generic quality standards that are used to regulate land contamination. Soil SVs adopted in European countries are widely variable in multiple aspects. The use of SVs varies from setting long term quality objectives, via triggering further investigations, to enforcing remedial actions. Derivation methods of SVs have scientific and political bases; they also differ from country to country, and SVs numerical values vary consequently. In relation to the common market and common environmental policies in Europe, this variability has raised concern among both regulators and risk assessors. As reported in the Soil Thematic Strategy discussion documents (Van Camp et al., 2004), a further alignment of European SVs derivation methods is generally supported. To what extent this can be done and the possible drawbacks are still matter for discussion. The idea of a toolbox approach, which addresses the harmonization of specific building blocks of SVs derivation procedures while giving wide room for national diversities, was already discussed and encountered significant favor in an expert meeting in Ispra in February 2005 (Carlon, 2005). Nevertheless, it was also clear at that time that a detailed analysis of commonalities and differences among European national approaches, essential for the evaluation of the technical feasibility of harmonization, was lacking. In particular, besides the identification of differences, a further insight was necessary on the reasons for the differences. Based on this consideration, the idea of the present review was launched.
The present review analyses the bases of screening values used in EU Member States and initiated a discussion on the reasons for their differences. Specific objectives of the review were the following:
• to describe the state of the art of SVs derivation methods and their application in Europe,
• to assess commonalities and main differences among national methods,
• to gain a further insight in reasons of differences,
• to identify opportunities for harmonization.
The work focused on soil contamination, but also investigated the relation between the soil and groundwater SVs.