Mobility of the Dissolved Organic Matter through Intact Boom Clay Cores

Performance assessment studies are expected to predict the enhancement of the migration of trivalent lanthanides and actinides due to their complexation with organic matter, which play a role as a transport agent [1]. Therefore, the mobility of the dissolved organic matter in the interstitial Boom Clay water is studied. For the first time, the mobile fraction present in the clay water is concentrated and labelled with a radioisotope to study the mobility of the organic matter in clay and the interaction of the mobile with the non-mobile. The isotopes tested as label are ¹²⁵I and ¹⁴C. The ¹²⁵I label proved to be unstable and hence discarded. The labelled organic matter is then diluted for migration experiments on Boom Clay cores under anaerobic conditions. The influence of the molecular size on its mobility is studied by the separation of the labelled organic matter in different size fractions.