26 
Compilation of Summaries 
over the Norwegian Deep for 137 Cs and 90 Sr can be explained by the Baltic Sea 
outflow, which still carries higher concentrations than the water of the North 
Sea as a result of the Chernobyl reactor accident fallout, and the limited water 
exchange in the Baltic Sea. 
On the basis of the activity ratios, the increased activity concentrations of tran- 
suranic elements in the area of the Elbe and its estuary definitely did not origi 
nate from the global weapon fallout, but cannot be assigned to a local source. 
In the latter case, other man-made radionuclides would also have to be found 
in significantly higher concentrations, which was not the case. With our current 
level of understanding, the only theory that remains is that of enrichment in the 
tidal Elbe via natural transportation processes due to the enrichment of sus 
pended matter. The increased concentrations to the north and east of the Brit 
ish Isles can be explained by re-suspension material from Irish Sea sediments. 
The occasional, anomalous increase of 238p u /(23o+240)p u activity ratios in the cen 
tral North Sea in 2009 can be attributed to a clean-up operation near to the 
Dounreay facility. 
The specific activity in surface sediment samples of the German Bight has con 
tinuously declined in the past ten years with regard to 137 Cs and ( 239+24 °)pu, which 
gives hints to the re-suspension of contaminated sediment with these radionu 
clides. The sediment in the central German Bight shows a typical “Sellafield” 
derived radionuclide vector, while there is a pure fallout ratio southeast of Heli 
goland. 
Based on the information presently available, radiological consequences are 
not expected. The average total effective dose is 4 mSv per year and per per 
son in Germany, half of which can be attributed to medical and particularly di 
agnostic X-ray measures. The contamination of the North Sea from radionu 
clides only contributes to the population’s exposure to radiation via the route 
“consumption of fish or seafood”. Consumption of about 14 kg per year per 
person (average statistical consumption rate in Germany in 2013) results in a 
maximum effective dose of 0.3 pSv/a, which remains considerably lower than 
the “trivial dose for an individual source” according to the Radiation Protection 
Ordinance (10 pSv/a) and can therefore be neglected from the point of view of 
radiation protection. As there is no significant dose contribution for the popula 
tion resulting from the enrichment of radionuclides in the food chain, this may 
be deemed the case for flora and fauna as well.