Circular and nature-based innovations for stabilizing radiological contamination in soil

Sustainable management of nuclear legacy and NORM-contaminated sites remains a major environmental challenge. Traditional remediation methods, such as soil excavation, often generate large volumes of radioactive waste and incur high costs. This PhD project directly supports SCK CEN’s strategic objective to bring forward novel solutions to remediate nuclear legacy sites or NORM sites by developing and validating nature-based remediation strategies that stabilize residual radionuclide contamination in soils.

The research will examine how plant–microbe interactions, combined with selected circular soil amendments, specifically phosphogypsum residues and biochar- can affect the leachability, retention, and bioavailability of radionuclides in historically contaminated soils, supplemented with mechanistic tests on spiked soils where needed. Through laboratory assays, microcosm experiments, and semi-field validation, the project will identify the biotic and geochemical processes that most effectively stabilize radionuclides under realistic conditions and will contribute to identifying cost-effective and environmentally responsible approaches for long-term site management. Special focus will be given to the use of residual industrial materials such as phosphogypsum and biochar as stabilizing agents, demonstrating how waste products can be repurposed into remediation tools. Experimental data will be integrated into a simplified first order soil–vegetation–atmosphere (SVAT) model, a “box” model, enabling the prediction of radionuclide stabilization dynamics over time based on the obtained transfer rates between soil and plant components. The innovative strength of this project lies in its multidisciplinary integration of environmental radioecology, biogeochemistry, and systems modelling within a sustainability framework. It moves beyond end-of-pipe solutions to propose in-situ, low-impact, and circular approaches for the management of contaminated sites. The expected outcome will generate scientific insights into radionuclide behavior and mobility in soil types that can support recommendations on novel remediations strategies compared to traditional remediation approaches.