have actively participated in many other 
intercomparisons, in many cases coordinated 
by the IAEA and NKS (Nordic Nuclear Safety 
Research). 
5 Conclusions 
The radiochemical procedures and counting 
techniques used by laboratories are well- 
tested, up-to-date, and similar to those 
used by laboratories worldwide. The eight 
intercomparisons organized by the MORS 
group during the period 1999-2006 confirm 
that the data produced by the MORS group 
is of very good quality and can be considered 
comparable. Less than five percent of the 
results were considered outliers. At the 
same time the reported uncertainties vary 
considerably between laboratories. Each 
laboratory calculates uncertainties in its own 
particular way, and the harmonization of 
uncertainty calculations would improve the 
comparability of the data. 
References 
Ikaheimonen, T.K. & V. Vartti (2007): 
An intercomparison of Radionuclide 
Analyses in a Baltic Sea Sediment 
Sample. In: HELCOM (2007): Long- 
lived radionuclides in the seabed of the 
Baltic Sea. Balt. Sea Environ. Proc. No. 
110:25-41. 
Ikaheimonen, T.K. & S. Mulsow 
(2003): Data quality. In: HELCOM (2003): 
Radioactivity in the Baltic Sea 1992-1998. 
Balt. Sea Environ. Proc. No. 85:49-54.