April 21, 2026 by Lucy Kennelly

wca are collaborating with the University of Saskatchewan, the Finnish Environment Institute (SYKE), Australia’s Department of Climate Change, Energy, the Environment and Water (DCCEEW), the UK Centre for Hydrology and Ecology (UKCEH) and industry clients to develop the first chronic bioavailability model for uranium.

In parts of Europe, natural background concentrations of uranium can exceed the existing Environmental Quality Standard (EQS). It is widely recognised that many biological and chemical factors can influence the behaviour and ecotoxicity of metals, including uranium, in surface freshwaters. To account for these factors, and provide a means to utilise an ecologically relevant metric to assess potential environmental risks from metals, it is necessary to consider uranium bioavailability. Bioavailability models are widely used to predict the ecotoxicity of metals from abiotic factors such as pH, hardness and dissolved organic carbon (DOC). An attempt has previously been made to develop a bioavailability model for uranium (the STAR project), but this used limited, mostly acute, datasets and was not finalised.

Our chronic bioavailability model is being developed based on long-term toxicity tests with algae (Chlorella vulgaris), aquatic invertebrates (Hydra viridissima), and fish (Danio rerio) conducted by DCCEEW and the University of Saskatchewan. These tests are investigating the influence of several toxicity modifying factors including pH, hardness and DOC, with additional tests to assess the effects of other potential competing ions such as sodium. The model will be validated by testing at SYKE and the University of Saskatchewan with different species from the three trophic levels (Raphidocelis subcapitata, Daphnia longispina /Daphnia magna, and Oncorhynchus mykiss) in natural field-collected waters from Sweden, Finland and Canada, covering a wide range of water chemistry conditions.

The development and validation of the model is expected to be completed by the end of the calendar year. The model will then be applied to derive European and Swedish-specific EQS in line with EU guidance, and a simplified, user-friendly tool based on the model will be produced.

Our activities at SETAC Maastricht for this project:

We are presenting three posters on Monday in the Exhibition Hall under Session 3.12 “Fate and Toxicity of Metals: Recent Scientific Advancements and Their Application in Environmental Regulations”. Lucy will be presenting her poster in the Poster Corner for Session 3.12 in the Expo Foyer (Level 1, MECC) on Monday at 16:00 – 16:45.

Posters:

• The Development and Regulatory Implementation of a Bioavailability Model for Uranium (Lucy Kennelly)
• Uranium toxicity to algae and water flea in natural freshwaters. Validating Biotic Ligand Model for uranium (Matti Leppänen, presented by Lucy Kennelly)
• Uranium Toxicity to Zebrafish in Reconstituted Freshwater at Different pH and Ionic Composition (Karsten Liber)

We also have a poster on Thursday in the Exhibition Hall:

• Uranium toxicity to freshwater biota at varying pH, hardness and dissolved organic carbon (Melanie Trenfield, presented by Lucy Kennelly)

In addition, Lucy will be presenting our work in the Metals Interest Group (MIG) meeting, which will take place in the MECC Café on Tuesday at 18:00 – 20:00.

If you would like to discuss this project with us at SETAC, you can find Lucy at the wca stand in the exhibition hall (Booth 81).

Get in touch

For more information on this project, the bioavailability of metals, EQS derivation, or anything else you’d like to discuss, please contact us.