Ecotoxicity of surface sediments of Lake Geneva

In surface waters, sediments play an important role not only as a sink, but also as a source of pollutants. Mainly hydrophobic pollutants adsorb to particles and can be re-released depending on the environmental conditions, thereby contributing to water pollution. The sediments of Lake Geneva were last analysed 27 years ago. Therefore, a fresh assessment of the sediment quality is necessary. Therefore, CIPEL (Commision internationale pour la protection des eaux du Léman) has funded the project SedLem15 piloted by the Forel Institute (University of Geneva) that aims to address this gap. In this collaborative monitoring project, 80 sediment samples are being analyzed for 45 sediment-relevant compounds and sediment characteristics. Four samples of zoobenthos have been also analysed for the biological quality of the lake. The Ecotox Centre contributes by testing 30 selected samples for toxicity to ostracod and for oestrogenic mode of action, and few samples for toxicity to chironomids and macrophytes in the laboratory. The influence of the mode of conservation (fresh vs. frozen vs. freeze-dried) on the toxicity to ostracods will be also evaluated. This contribution will provide valuable information for the application and interpretation of laboratory results to evaluate sediment quality. A map of ecotoxicity of the Lake Leman will be also provided to complete the chemical approach.

Applied test systems

• Chronic Toxicity Test with Chironomids
• Sediment Contact Test with Myriophyllum aquaticum
• Sediment Contact Test with Heterocypris incongruens
• Yeast Estrogen Screen test assisted by enzymatic digestion with lyticase (LYES test)
• Combined Algae Test

Final report

Micropolluants métalliques et organiques dans les sédiments superficiels du Léman