The bone ash standard reference material (SRM), a blend of 4% contaminated human bone and 96% diluent bovine bone, has been developed for radiochemical method validation and quality control for radio-bone analysis. The massic activities of 90Sr, 226Ra, 230Th, 232Th, 234U, 235U, 238U, 238Pu, ((239+240))Pu and ((243+244))Cm were certified using a variety of radiochemical procedures and detection methods. Measurements confirmed undetectable radionuclide heterogeneity down to a sample size of 5 g, thereby implying adequate blending of particulate materials with dilution factors of up to 17,900. The results among most of the intercomparison laboratories and their methods were consistent. Disequilibrium was observed for decay chains: 234U(0.67 mBq/g)- 230Th(O.47 mBq/g)-226Ra(15.1 mBq/g)-210Pb(23 mBq/g)-210Po(13 mBq/g) and 232Th(0.99 mBq/g)-228Ra(6.1 mBq/g)-228Th(7.1 mBq/g). The disequilibria were the results of mixing occupationally contaminated human bone with natural bovine bone and the fractionation during internal biological processes. The massic activity of 210Pb, 228Th and 241Am were not certified because of insufficient 228Ra and 241Pu data and lack of knowledge in how 222Rn and its daughters will be fractionated in the SRM bottle over time.
|Number of pages||6|
|Journal||Applied Radiation and Isotopes|
|Publication status||Published - Aug 1998|
|Event||Proceedings of the 1997 Conference on Radionuclide Metrology and its Applications, ICRM'97 - Gaithersburg, MD, USA|
Duration: 19 May 1997 → 23 May 1997
Bibliographical noteFunding Information:
The authors gratefully thank the Standard Reference Materials Program of National Institute of Standards and Technology for funding this work. Dr Simon Jerome (National Physics Laboratory, U.K.) is also thanked for assistance in the European intercomparison measurements and comments in preparing of this manuscript.