Derivation of ecotoxicological quality criteria for surface waters

Many surfacewater are polluted with micropollutants such as pharmaceuticals, pesticides and industrial chemicals, which can harm aquatic organisms even at very low concentrations. The most high-risk micropollutants in surface waters must be measured and assessed so that the cantons and the federal government can take measures to reduce them. In order to identify the most relevant micropollutants, recurring special analyses are required, for which ad-hoc quality criteria are needed to assess the risk. In addition, the highest-risk micropollutants must be recorded and ecotoxicologically assessed in the national surface water quality monitoring programme NAWA. Ecotoxicological quality criteria are also required here for risk assessment. The Ecotox Centre develops these quality criteria on behalf of the FOEN.

The EU has determined new proposed quality criteria for micropollutants for the Water Framework Directive, which are due to come into force around summer 2024. The Ecotox Centre is examining the transferability of these proposed limit values to Switzerland and is working on the completion of the dossiers in the EU for micropollutants already prioritised in Switzerland. In addition, the Ecotox Centre develops ad-hoc quality criteria to assess the risk for the micropollutants covered by the current special campaign. For the micropollutants prioritised via the NAWA selection process, the Ecotox Centre derives the necessary quality criteria to correctly assess the existing risk in water bodies. In addition, a certain number of existing quality criteria are updated on the basis of new scientific findings.