Uranium decay daughters from isolated mines: Accumulation and sources

Area of Science:

• Environmental Science
• Geochemistry
• Nuclear Science

Background:

• Former uranium mine sites can be sources of radioactive contamination.
• Understanding radionuclide distribution is crucial for environmental remediation.

Purpose of the Study:

• To precisely locate radioactive contamination pools near a former French uranium mine.
• To identify specific radionuclides and their distribution from soil to mineral phases.
• To assess the mobility of key radionuclides using sequential extraction.

Main Methods:

• In situ gamma spectrometry at multiple scales.
• Sequential extraction techniques for radionuclide mobility assessment.
• Mineralogical analyses coupled with extraction data.

Main Results:

• An accumulation area downstream of the mine was identified, concentrating significant radioactivity.
• Disequilibria in uranium decay chains suggest mining process influence.
• Radium-226 was found in the residual phase, associated with barium sulfate (Ba(Ra)SO4).
• Uranium was primarily located in the reducible fraction, potentially adsorbed onto mineral surfaces.

Conclusions:

• The study successfully mapped contamination hotspots and identified radionuclide carriers.
• Barium sulfate acts as a sink for Radium-226, while uranium mobility is linked to reducible soil components.
• Findings provide critical data for targeted remediation strategies at uranium mining sites.