Spatial Distribution of Cesium-137 in the Northeastern Part of Burkina Faso

The concentration of cesium-137 is determined in the northeastern part of Burkina Faso in order to evaluate its contribution to the radiological anomaly of the locality. The measured values of specific activity, for a soil depth of 20 cm, vary between <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.52\pm 0.06Bq\cdot kg^{-1}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.59\pm 0.09Bq\cdot kg^{-1}$</tex> with an average value of 0.97 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Bq\cdot kg^{-1}$</tex>. The presence of cesium-137 in this region shows that it suffered contamination following a nuclear test. However, this contamination remains negligible. In addition, the measurement of the specific activities of cesium-137 for a depth of 40 cm at Nyapsi locality shows that the presence of this radionuclide is almost zero at this depth. Furthermore, the statistical analysis of the available data shows a slight correlation of cesium-137 with uranium-238 and thorium-232 and an absence of correlation with potassium-40. This slight correlation is supported by a very strong correlation between uranium-238 and thorium-232. The spatial distribution of cesium-137 is heterogeneous and its contribution to the radiological anomaly of the locality is negligible.