NUKLEONIKA 2006, 51(Suppl. 2):s45-s51

The paper presents the results of determination of natural [polonium (²¹⁰Po), uranium (²³⁴U, ²³⁵U, ²³⁸U)] and artificial radionuclides [iron (⁵⁵Fe), nickel (⁶³Ni), and plutonium (²³⁸Pu, ^239+240Pu, ²⁴¹Pu)] in Poland and the southern Baltic Sea ecosystem as well as the recognition of their accumulation process in the trophic chain. All presented results is a summary of long lasting studies realized by the present authors. Results of this study indicated that the principal sources of ⁵⁵Fe and ⁶³Ni in the Baltic Sea environment is the release from Swedish nuclear power plants. Investigation on the polonium ²¹⁰Po and plutonium ²³⁸Pu, ^239+240Pu and ²⁴¹Pu concentration in Baltic and land biota revealed that these radionuclides are strongly accumulated by some species. Moreover, it was found that fish, mushrooms, cigarettes constitutes important sources of ²¹⁰Po for people. The Baltic Sea algae, benthic animals and fish concentrate uranium only to a small degree. In Baltic sediments, the concentration of uranium increases with core depth and it is connected with the diffusion of ²³⁴U, ²³⁵U and ²³⁸U from sediments. The values of ²³⁴U/²³⁸U activity ratio in the sediments indicated that the reduction process of U(VI) to U(IV) and the removing of autogenic uranium from seawater to sediments in the Gdańsk Deep constitutes a small part only.