Background Po activity concentrations in Greenland marine biota and dose assessment.

Polonium-210 (Po) is a radionuclide sentinel as it bioaccumulates in marine organisms, thereby being the main contributor to committed dietary doses in seafood consumers. Although seafood and marine mammals are an important part of the traditional Inuit diet, there is a general lack of information on the Po concentrations in the Greenlandic marine food chain leading to the human consumer. Here, we determine background Po concentrations in edible parts of different marine organisms from Greenland and provide a dose assessment. Blue mussels (Mytilus edulis), organs of ringed seal (Pusa hispida) and polar bear (Ursus maritimus) displayed significantly elevated Po concentrations in respect to all other studied organisms (p < 0.001). Po concentrations ranged from 0.02 Bq kg, w.w. in Greenland halibut (Reinhardtius hippoglossoides) muscle to 78 Bq kg, w.w. and 202 Bq kg, w.w. in ringed seal muscle and kidneys, respectively. Po concentration ratio for edible parts increases in the order bladderwrack (Fucus Vesiculosus), northern shrimp (Pandalus borealis), blue mussels, and from fish species to ringed seal and polar bear. Po distribution in fish, ringed seal, and polar bear follows a general pattern, the lowest concentrations were in muscle, and the highest concentrations were in the organs involved in metabolism. The derived Po annual absorbed dose in edible parts of studied marine organisms are several orders of magnitude lower than the recommended dose rate screening value of 10 μGy h. Effective doses from intake of Po to Greenland average children (1.4 mSv y), and high seafood and marine mammal consumers (2 mSv y for adults and 3.6 mSv y for children) are higher than the world average annual effective dose due to ingestion of naturally occurring radionuclides.