Modelling Radionuclides Transport and Dose Assessment in a Groundwater System in Somita- Taparko Goldmine in Burkina Faso

Abstract

Radionuclides transport and dose assessment to the public in a groundwater system are described using theoretical and experimental methods. It is known that radionuclides could accumulate during mining and mineral ore processing and reach into water bodies, and thus contribute to the radiation dose received by the public who consume this water. As groundwater is inaccessible, a mathematical model with a numerical method is used to describe the relevant physical processes during radionuclide transport in the groundwater system. A computer programme has been written in MatLab to implement the numerical solution. The activity concentration and annual committed effective dose to the public from natural radionuclides (NORM) are determined for both theoretical and experimental methods. The NORM elements of interest are 238U, 232Th and 40K. The results obtained from the study revealed that the concentration of NORM in Taparko groundwater system increases with time at the point of release and becomes constant at a certain time. The concentration then decreases rapidly as far as from the release point. The average activity concentrations for theoretical method were 0.3 Bq/L, and 0.05 Bq/L for 238U and 232Th respectively at 600 m from the discharged point where the water from boreholes and wells is used by the public. For experimental analysis the mean activity concentrations were 5.57 Bq/L, 0.58Bq/L and 4.78 Bq/L for 238U, 232Th and 40K respectively. The corresponding average annual committed effective doses estimated were 0.13mSv/y, 0.28 mSv/y, for theoretical and experimental methods respectively. The theoretical and experimental results indicate insignificant exposure of the public to Natural Occurring Radioactive Materials (NORM) from the activities of the Goldmine.