Objective
Pathways of human exposure to radioactivity can only be recognised and quantified when the processes controlling transport and availability of radionuclides in the different compartments of the ecosphere are known. This project focuses on the fluxes and availability of radionuclides to the biosphere in freshwaters and follows a process-based approach in order to meet the two major objectives:
(1) The development of mechanistically-based and, hence, generally applicable whole-ecosystem models, to be applied in support of
(2) the advancement of a sound theoretical basis for chemical and hydrological countermeasures.
We believe that fundamental knowledge of individual processes has developed to the extent that it can now be made applicable in the form of submodels to be incorporated into whole-ecosystem radionuclide transport models. First steps in this direction have already been taken by members of this group and we have strong indications that both predictive power and general applicability of the ecosystem models can be greatly improved. The submodels are based on the pharmacokinetics of membrane transport for bioaccumulation/elimination, and on ion-exchange for solid/water partitioning. Submodels are also being developed for secondary contamination from catchments and diffusional sediment/water exchange. The models will be kept as small as possible, while maintaining a high predictability and general applicability, to allow their linkage to decision support systems and their use for management purposes. The project focuses on identifying essential environmental parameters controlling radionuclide mobility/bioavailability, such as radionuclide speciation, binding sites on particles and "fixation" properties, and elements controlling radionuclide binding to particles and uptake by biota. Knowledge of these parameters and effects is mandatory for the construction of generally applicable models. Because of their impact on radionuclide behaviour, it is these "operative' parameters that should form the theoretical basis of restorative techniques for the reduction of radionuclide mobility and availability to the aquatic food chain.
We intend to investigate whether the identified "operative" parameters can be manipulated and to assess the effect on the different geochemical and biological compartments of the ecosystem. We believe that such an assessment can only be reliably made by using a whole-ecosystem model which includes the fundamental mechanisms of radionuclide transfer between these compartments, i.e. our first objective.
Work Packages include the development of mechanistic submodels for bioaccumulation/elimination, solid/liquid partitioning and availability, and mechanistically-based whole-ecosystem models; development and assessment of chemical/hydrological counter-measures; and validation of the above models under controlled laboratory conditions, large-scale controlled flow chambers, and in-situ. Our objectives will be delivered as
(1) whole-ecosystem models including mechanistic submodels,
(2) manuals on how to use them and to obtain/estimate the necessary parameters,
(3) an assessment of countermeasures and recommendations to the EC.
Programme(s)
Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
PETTEN
Netherlands