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Contenu archivé le 2022-12-23

The modelling and study of the mechanisms of transfer of radioactive material from terrestrial ecosystems to and in water bodies

Objectif

The possibility of significant remobilisation of radionuclides from a catchment suggests that lakes and rivers (and ground waters in some catchments) may contain significant concentrations of caesium and strontium for much longer times than might have been expected. The objectives of this project are to investigate the processes of remobilisation of radionuclides from lake and river catchments.

Concentrations of radioactivity in fish collected after the Chernobyl accident showed a considerable amount of scatter; these differed by two orders of magnitude for fish of the same species collected on the same day. This variability is reduced in some species, but apparently not in all, when allowances are made for differences in fish size. Major objectives of the project are to determine the importance of feeding physiology on the variability of radionuclide levels in fish at different trophic levels, to incorporate the basic processes into a functional model radionuclide transfer to fish and to incorporate this information into sampling programmes for dose estimation in man.

Experimental projects should be undertaken with the following main objectives:

radiocaesium mobilisation from fresh water sediments and flooded peat soils should be quantified.

the importance of frayed edge sites on illite mineral grains for the long term immobilisation of caesium should be investigated together with its displacement by inorganic and/or organic chemical species.

the importance of particle resuspension and subsequent radionuclide reequilibration should be investigated as a potential means of remobilisation; the dominant remobilisation processes should be defined, correlating pore water chemistry and caesium.

estimates should be made of in situ Kd values and the environmental parameters which cause variations in space and time should be identified.

the results of the experimental programmes should be used in conjunction with other data to further improve models for assessing the migration of radionuclides to water bodies with a major emphasis on the catchment-to-water pathway.

Dynamics of accumulation of radionuclides in fish

the relationship between the concentrations of caesium-137 and strontium-90 in fish species of different trophic levels and in their food (zooplankton, marofauna) should be investigated.

the role of age and size on radionuclide uptake in fish.

stochastic models should be developed for assessing the variability of radionuclide contamination in fish.

Thème(s)

Data not available

Appel à propositions

Data not available

Régime de financement

CSC - Cost-sharing contracts

Coordinateur

NERC Institute of Freshwater Ecology
Contribution de l’UE
Aucune donnée
Adresse
The River Laboratory East Stoke
BH20 6BB Wareham
Royaume-Uni

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Coût total
Aucune donnée

Participants (3)