In this paper, the results of Pu-238 and Pu239+240 determinations in four r
epresentative species of Baltic fish collected in Gdansk Bay: flounder, her
ring, cod and sprat, are presented and discussed. The plutonium isotopes ar
e amongst the more radiotoxic nuclides. In the marine environment, the high
est concentrations of plutonium are found in the sediments, but the complex
biogeochemical cycle of the element means that it is also found in all oth
er compartments. The activities of the fish samples were measured using alp
ha spectrometry and the concentrations of plutonium Pu-238 and Pu239+240 we
re estimated for particular organs and tissues and the whole body. The Pu23
9+240 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 k
g(-1) w.w. On the basis of the Pu-238/Pu239+240 activity ratio in the organ
s and tissues, the proportion of Chernobyl-derived plutonium in the Baltic
Sea was calculated. The lowest values of Chernobyl plutonium were accumulat
ed in flounder stomach, herring skin, cod intestine, the highest in cod gil
ls and skin. (C) 2001 Elsevier Science Ltd. All rights reserved.