Microanalytical X-ray imaging of depleted uranium speciation in environmentally aged munitions residues.
Use of depleted uranium (DU) munitions has resulted in contamination of the near-surface environment with penetrator residues. Uncertainty in the long-term environmental fate of particles produced by impact of DU penetrators with hard targets is a specific concern. In this study DU particles produced in this way and exposed to the surface terrestrial environment for longer than 30 years at a U.K. firing range were characterized using synchrotron X-ray chemical imaging. Two sites were sampled: a surface soil and a disposal area for DU-contaminated wood, and the U speciation was different between the two areas. Surface soil particles showed little extent of alteration, with U speciated as oxides U3O7 and U3O8. Uranium oxidation state and crystalline phase mapping revealed these oxides occur as separate particles, reflecting heterogeneous formation conditions. Particles recovered from the disposal area were substantially weathered, and U(VI) phosphate phases such as meta-ankoleite (K(UO2)(PO4) · 3H2O) were dominant. Chemical imaging revealed domains of contrasting U oxidation state linked to the presence of both U3O7 and meta-ankoleite, indicating growth of a particle alteration layer. This study demonstrates that substantial alteration of DU residues can occur, which directly influences the health and environmental hazards posed by this contamination.
Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield , Mappin Street, Sheffield S11 7GL, United Kingdom.
Daniel E
DE
Crean
Francis R
FR
Livens
Martin C
MC
Stennett
Daniel
D
Grolimund
Camelia N
CN
Borca
Neil C
NC
Hyatt
D004577:Electron Probe Microanalysis; D006801:Humans; D008855:Microscopy, Electron, Scanning; D054043:Nuclear Weapons; D010084:Oxidation-Reduction; D010087:Oxides / Q000032:analysis; D011834:Radiation Monitoring / Q000379:methods*; D012987:Soil / Q000737:chemistry; D012990:Soil Pollutants, Radioactive / Q000032:analysis* / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D017356:Synchrotrons; D006113:United Kingdom; D014501:Uranium / Q000032:analysis* / Q000737:chemistry; D017974:Uranium Compounds / Q000032:analysis* / Q000737:chemistry
D010087:Oxides; D012987:Soil; D012990:Soil Pollutants, Radioactive; D017974:Uranium Compounds; D014501:Uranium