4 Modelling and Dose Calculations 41 
4.1 Model work 41 
4.2 Dose calculations 42 
5 Radioactivity in the Baltic Sea 
Compared to Other Sea Regions 47 
6 Conclusions 50 
7 Recommendations 52 
8 Acknowledgements 53 
Appendix: Data Quality 54 
1. Introduction 54 
2. Analytical procedures used by MORS laboratories 54 
3. Quality assurance, internal and external checking 54 
4. Intercalibration excercises (1999-2006) 
organized by the MORS group 54 
4.1 Sediment 54 
4.2 Seawater 55 
5. Conclusions 55