Characterisation of the IAEA-375 soil reference material for radioactivity measurements

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JRC scientists contributed to the upgrading of reference materials owned by the International Atomic Energy Agency (IAEA) by providing activity concentrations of a series of radionuclides in the IAEA-275 soil reference material. This well-characterised material was then used in an inter-laboratory comparison study in 2010 organised by the JRC.

Radioactivity levels in foodstuff and the environment are of particular concern; the dose to which humans are exposed depends directly on the level of radioactivity in the environment in which they live and the food they consume. The soil is a natural matrix important in environmental monitoring, as it affects humans both directly and via the food chain.
The JRC-Institute for Reference Materials and Measurements (IRMM) participated in a Coordinated Research Project (CRP) of the International Atomic Energy Agency (IAEA). This project aimed to upgrade existing reference materials and assign property values traceable to the International System of Units (SI). The JRC-IRMM received 6 bottles containing the IAEA-375 Soil Reference Material to determine the activity concentration of a series of radionuclides. The radionuclides 40K, 134Cs, 137Cs, 212Pb, 212Bi, 214Pb and 214Bi were measured by gamma-ray spectrometry after drying the sample and placing it in a suitable container. The 90Sr was assessed by liquid scintillation counting after the dissolution of the soil by wet digestion and chemical separation of Sr by extraction chromatography. This soil, CRM was used as the basis for the 2010 EC Interlaboratory Comparison on Radionuclides in Soil organised by the JRC-IRMM.

Certified reference materials (CRM) can be used to calibrate instruments, to evaluate and compare radiochemical separation and measurement procedures and ensure the comparability of measurement results among laboratories, especially those working in surveying and monitoring radioactive materials in the environment and the foodstuff. Few reference materials of environmental matrices, certified for their radioactivity contents, exist and even fewer whose values are traceable to the SI units.

Read more in: T. Altzitzoglou and A. Bohnstedt: “Characterisation of the IAEA-375 Soil Reference Material for radioactivity“, Applied Radiation and Isotopes 109 (2016) 118–121, doi:10.1016/j.apradiso.2015.11.053

JRC publication: “Characterisation of the IAEA-375 Soil Reference Material for radioactivity