Beate I. Escher Beate I. Escher Jörg Ahlheim Jörg Ahlheim Alexander Böhme Alexander Böhme Dietrich Borchardt Dietrich Borchardt Werner Brack Werner Brack Georg Braun Georg Braun John K. Colbourne John K. Colbourne Janek Paul Dann Janek Paul Dann Joern Gessner Joern Gessner Annika Jahnke Annika Jahnke Maria König Maria König Nils Klüver Nils Klüver Martin Krauss Martin Krauss Jungeun Lee Jungeun Lee Xiaojing Li Xiaojing Li Stefan Lips Stefan Lips Luisa Orsini Luisa Orsini Karsten Rinke Karsten Rinke Mechthild Schmitt-Jansen Mechthild Schmitt-Jansen Stefan Scholz Stefan Scholz Tobias Schulze Tobias Schulze Stephanie Spahr Stephanie Spahr Nadin Ulrich Nadin Ulrich Markus Weitere Markus Weitere Elisabeth Varga Elisabeth Varga Nature 2024 Prymnesins produced by an algal bloom of Prymnesium parvum led to the death of several hundred tons of freshwater fish in the Oder River in summer 2022. We investigated effects on aquatic life and human cell lines from exposure to extracts of contaminated water collected during the fish kill. We detected B-type prymnesins and >120 organic micropollutants. The micropollutants occurred at concentrations that would cause the predicted mixture risk quotient for aquatic life to exceed the acceptable threshold. Extracts of water and filters (biomass and particulates) induced moderate effects in vivo in algae, daphnids and zebrafish embryos but caused high effects in a human neuronal cell line indicating the presence of neurotoxicants. Mixture toxicity modelling demonstrated that the in vitro neurotoxic effects were mainly caused by the detected B-type prymnesins with minor contributions by organic micropollutants. Complex interactions between natural and anthropogenic toxicants may underestimate threats to aquatic ecosystems. PDFDocument eng 2025-02-20T08:57:50.371740Z 2024 Effluents Water Risk 1295136 b application/pdf http://creativecommons.org/licenses/by/4.0/