Radioactivity In Marine Organisms From Northeast Atlantic Ocean

Abstract

Naturally‐occurring radionuclides such as 238U, 234U, 230Th, 226Ra, 210Po, 210Pb and 232Th, and artificial radionuclides such as 137Cs, 239+240Pu and 241Am, were measured in a large number of marine species. In common fish species, typical concentrations of 210Po ranged from 102 to 104 mBq kg−1 (wet weight), 226Ra concentrations ranged from 1×102 to 5×l02 mBq kg−1, 238U was at about 10 mBq kg−1 and 232Th at about 0.5 mBq kg−1. Radiation doses to marine organisms originated by naturally‐occurring and artificial radionuclides accumulated in tissues and by external radiation sources were computed and compared. Internal sources generally give higher contribution to the absorbed radiation dose than external sources. Amongst radionuclides accumulated in fish muscle and acting as internal radiation sources, natural 210Po and 40K give the largest contribution to the absorbed radiation dose, while artificial radionuclides such as 137Cs and 239+240Pu contribute with less than 0.5% to the absorbed radiation dose from all internal sources.