Community Research and Development Information Service - CORDIS

FP5

Processes Regulating Remobilisation, Bioavailability, and Translocation of Radionuclides in Marine Sediments (REMOTRANS)

Project ID: FIGE-CT-2000-00085
Funded under: FP5-EAECTP C

Abstract

Marine sediments in European waters have become contaminated by artificial radionuclides as a result of a variety of planned and unplanned human activities. For example, radioactive waste has been discharged into the Irish Sea as a consequence of reprocessing radioactive waste at Sellafield (formerly Windscale) since 1952. In the intervening period approximately 610 TBq of 239+240Pu and 41 PBq of 137Cs have been discharged. As plutonium is a particle reactive substance, much of it has been removed from the water column and has found its way to the fine grained, muddy sediments of the west coast of Britain. Radiocaesium is more conservative in seawater but it can be scavenged by particulates, especially in coastal waters in association with clay particles. In addition, there have been significant releases of 99Tc during different periods and also radionuclides such as 237Np and 129I. These more conservatively behaving radionuclides have been used as tracers for the water movements and mixing from the source. Releases from the French reprocessing facility, La Hague, have also contributed to increased concentrations of artificial radioactivity in European waters, in particular 129I and 125Sb, but the overall contribution has been relatively small.
The Baltic Sea was the sea which was most contaminated following the Chernobyl accident. The inventory of 137Cs is estimated to be 5 PBq. The Baltic Sea is a marginal sea and is especially vulnerable due to its lower salinity, which causes higher Concentration Factors (CFs) in biota. While caesium is substantially more conservative than plutonium, much of the activity in the shallow Baltic sea has also been deposited in the sediments.

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Record Number: 8340 / Last updated on: 2007-02-01
Category: PROJ