Determination of Depleted Uranium in Environmental samples using Thermal Ionization Mass Spectrometry

The military use of depleted uranium (DU) initiated the need for an efficient and reliable method to detect and quantify DU contamination in environmental samples. A chemical and mass spectrometric procedure for uranium isotopic analysis using a thermal ionization mass spectrometer (TIMS) equipped with a wide aperture retardation potential energy filter has been developed and applied to determination of 238U, 236U, 235U and 234U isotopes in south Serbian soil samples. Soil samples were digested using a microwave digestor. The concentration of uranium in soil samples has been determined by inductively coupled plasma mass spectrometry. The isotope ratios were measured for two certified reference materials using a VG Sector 54-30 TIMS in dynamic mode with Faraday cup and Daly ion-counting system. Precision of the 235U/238U ratio was achieved by a correction factor of 0.22% amu as a function of ion beam intensity with a sample load of 250 ng of U. The resulting reproducibility for standards and soil samples are better than 0.2% at two standard deviations. Based on the uranium content and 235U/238U atom ratio in south Serbia soil samples, it will help to assess the influence of DU added to the surface environment. Detection of 236U in soil samples due to DU contamination can be useful as a marker for anthropogenic uranium in the environment.The 32nd FACSS and 51st ICASS Meetin