Mechanisms of mobility and bioavailability in the terrestrial environment

Evaluation of risk associated with food chain contamination actually largely relies on models using empirical parameter values for radionuclide mobility and soil-to-plant transfer. Knowledge on the physico-chemical conditions governing the radionuclide availability and speciation in the exposure medium and hence its bioavailability, uptake and redistribution in biota is indispensable when wishing to assess the impact of radioactive contamination on men, non-human biota or on an ecosystem.

Research on the behaviour of radionuclides

Through experimental research we aim at understanding the soil, plant and rhizopshere processes governing radionuclide availability and transfer in the food chain in order to come to a better predictability of the transfer and resulting radiation exposure for man and environment. To this end we have the required infrastructure available (plant growth chambers, green houses, lysimeters, measurement equipment). Study tools and models are developed to better study specific processes. The research is partially performed in the context PhDs and is done in collaboration with Belgian universities and international organisations.

Radionuclides of natural origin

Study of the behaviour of radionuclides in the terrestrial environment has the last 5 years mainly concentrated on radionuclides of natural origin (with emphasis on uranium and radium). These radionuclides are important with respect to environmental contamination linked with exploitation of materials containing naturally occurring radionuclides (NORM: e.g. P-industry and Ra refinery in Belgium) but are also radionuclides of concern in waste disposal. In this context, in depth research has been performed to predict U and Ra mobility and soil-to-plant transfer based on soil characteristics and on the role of plant characteristics and rhizosphere interaction on transfer.
We also studied the feasibility of enhanced phytoextraction for the remediation of U contaminated land. In the frame of the EC-MYRRH project we studied the effect of mycorrhiza on the transfer of U.

Radiocaesium

In the aftermath of the Chernobyl accident we have been involved in a large number of projects dealing with contaminated land management. One of the radionuclides of major importance in the medium to long term after an accidental atmospheric release is radiocaesium. In the context of post-emergency land management issues, we actually screen and study soil testing methods and bioassays with the aim to come up with a system of soil vulnerability classification based on soil and plant characteristics.

Heavy metals

We also collaborate with universities and research institutes to unravel the processes governing transfer of heavy metals by using radioactive tracers.

Future developments

Future research will concentrate on study of critical radionuclides in radioactive waste disposal (e.g. Nb, Ni, Se, …) and for the MYRRHA fast spectrum reactor.

People: Vandebroek Louis, Vandenhove Hildegarde, Van Hees May, Wannijn Jean