Levels of Tc-99 in seawater and biota samples from Norwegian coastal waters and adjacent seas

In 1994, the Enhanced Actinide Removal Plant at British Nuclear Fuels' Sell afield began operation, treating the backlog and continuous throughput of r adioactive wastes from reprocessing. This led to a significant increase in the levels of technetium-99 (Tc-99) discharged from Sellafield compared wit h the early 1990s. This study was conducted in order to establish the level s of Tc-99 in sea water and biota (calculating concentration factors where possible) arising from these newly increased discharges. sea mater activity levels of 0.9-8.5 Bq/m(3) mere recorded in 1996 compared with levels <1 Bq l/m(3) in the period 1990-1992. A clear increase in Tc-99 levels in seaweed samples was observed in Outer Oslofjord between 1996 and 1997. For all sit es, highest levels of Tc-99 were observed in seaweed and lobster samples (m aximum levels of 170 and 270 Bq/kg, dry weight, respectively). The results suggest that the initial plume of Tc-99 from the increased discharges, had reached the Norwegian coast sometime before November 1996, (C) 1999 Elsevie r Science Ltd. All rights reserved.