Integrating uranium radiological ingestion risk into environmental safety assessment alongside radium

Uranium's radiological ingestion risk remains underrecognized relative to radium. Using WHO/ICRP benchmarks and ICRP dose coefficients, this study shows that uranium-238 produces about 1.6 times more ingestion cancer risk than radium-226 at guideline concentrations. A U/Ra ratio of ~6 marks the threshold above which uranium becomes the larger contributor to radiological ingestion risk, a condition often met in near-surface environments. These findings indicate that uranium's radiological role has been consistently understated and support its inclusion alongside radium in regulatory and monitoring frameworks. Recognizing uranium's radiological impact alongside radium would also strengthen the coherence of protection frameworks linking nuclear and environmental domains.