REACTIVE TRANSPORT MODELING OF URANIUM IN GROUNDWATER

Modeling migration of uranium in groundwater is important for both groundwater protection and rehabilitation strategies of uranium mining sites due to the fact that uranium is both a radioactive element and an element with high chemical toxicity. Advection, dispersion, dilution, sorption and chemical interactions both in water and between water and solids have to be taken into account. This paper presents results which have been done in the context of the feasibility study for the in situ leaching mine Koenigstein near Dresden(Germany). Since reactive transport modeling is consuming a lot of CPU time all runs were performed 1 d but taken into account dilution by means of a simple mixing approach. PHREEQC version 2.2 proved to be a powerful tool for this kind of investigations. The database WATEQ4F which comes with PHREEQC containing 48 elements, more than 400 species and more than 300 minerals, was modified with respect to uranium and radium making it more consistent and reliable.