Characterisation of the IAEA-375 Soil Reference Material for radioactivity

The Joint Research Centre Institute for Reference Materials and Measurements (JRC-IRMM) participated in a research project initiated by the International Atomic Energy Agency (IAEA) to upgrade some of its existing reference materials (RMs). The aim of the work described in this article was to determine the activity concentration of a series of radionuclides in the IAEA-375 soil RM with values traceable to the SI units. The radionuclides ⁴⁰K, ¹³⁴Cs, ¹³⁷Cs, ²¹²Pb, ²¹²Bi, ²¹⁴Pb and ²¹⁴Bi were measured by γ-ray spectrometry after drying the sample and placing it in a suitable container. The ⁹⁰Sr was assessed by liquid scintillation counting after dissolution of the soil by wet digestion and chemical separation of Sr by extraction chromatography. This soil RM was used later as basis for the 2010 EC Interlaboratory Comparison on Radionuclides in Soil. - Highlights: • Upgrade of the IAEA-375 Soil Reference Material (RM). • Massic activity values traceable to the SI units. • ⁴⁰K, ¹³⁴Cs, ¹³⁷Cs, ²¹²Pb, ²¹²Bi, ²¹⁴Pb and ²¹⁴Bi measured by γ-ray spectrometry. • Chemical separation of Sr by extraction chromatography. • ⁹⁰Sr assessed by liquid scintillation counting. • The RM was used for the 2010 EC Interlaboratory Comparison on Radionuclides in Soil.