Bioaccumulation and distribution of plutonium in fish from Gdansk Bay

In this paper, the results of 238Pu and 239+240Pu determinations in four representative species of Baltic fish collected in Gdansk Bay: flounder, herring, cod and sprat, are presented and discussed. The plutonium isotopes are amongst the more radiotoxic nuclides. In the marine environment, the highest concentrations of plutonium are found in the sediments, but the complex biogeochemical cycle of the element means that it is also found in all other compartments. The activities of the fish samples were measured using alpha spectrometry and the concentrations of plutonium 238Pu and 239+240Pu were estimated for particular organs and tissues and the whole body. The 239+240Pu concentrations for fish species were: flounder 0.94 mBq kg−1 w.w., herring 2.22 mBq kg−1 w.w., cod 2.35 mBq kg−1 w.w. and sprat 0.33 mBq kg−1 w.w. On the basis of the 238Pu/239+240Pu activity ratio in the organs and tissues, the proportion of Chernobyl-derived plutonium in the Baltic Sea was calculated. The lowest values of Chernobyl plutonium were accumulated in flounder stomach, herring skin, cod intestine, the highest in cod gills and skin.