Radioactivity in Fucus vesiculosus L. from the Baltic Sea following the Chernobyl accident

Abstract

The brown alga Fucus vesiculosus L. has been used as a bioindicator for the investigation of the impact of the Chernobyl accident on the spatial and temporal distribution of radionuclides in the Baltic Sea. The investigations were performed in July 1986, about 2 months after the accident, and in August–September 1987. In July 1986 the gamma-emitting radionuclides 134Cs, 137Cs, 103Ru, 106Ru and 110 m Ag were detected in F. vesiculosus along the Swedish east, south and southwest coasts. The activity concentrations of 137Cs varied from 600 Bq/kg (dry wt) at the northernmost locality (Simpnäs) to 20 to 25 Bq/kg (dry wt) at the southeast coast. In August–September 1987 the activity concentrations of radiocaesium had increased by a factor of 2 to 3 at most localities off the Swedish east coast, compared with the results from 1986. We did not observe any increase of transuranic radionuclides or 99Tc in the algae. The subsequent extent of the radionuclide contamination in the Baltic Sea, primarily caesium, from Chernobyl was studied at one locality on the Swedish south coast from April 1987 to November 1988. A pronounced increase in the activity concentrations was observed during 1988, indicating an outflow of water, containing relatively higher levels of Chernobyl derived radionuclides, from the Baltic Sea.