Intercomparison of laboratory analyses of radionuclides in environmental samples, 2004-2005

An intercomparison exercise of radionuclides in environmental samples and foodstuffs has been carried out. A total of 821 analytical results were received from 38 laboratories. Half of the laboratories are from the Nordic countries and the other half from Estonia, Latvia, Lithuania, Poland, Russia and Hungary. The concentrations of radionuclides in the samples were unknown for what reason the evaluation was based on comparison with median values. However, one of the samples (soil) was a certified reference material (IAEA-375), and for this sample good agreement was found between the median values and the certified values. The comparison shows generally good agreement between laboratories with some exceptions. Results for which the agreement is not good include 90Sr, 241Am, 210Pb and total alpha and total beta. Less than half of the participants meet the evaluation criteria concerning these results. For these analyses there seems to be a particular need for improved analytical quality and testing of the results in international intercomparison exercises. (au)