Determination of Naturally Occurring Radionuclides and Heavy metals in Pegmatite Rock Using Energy Dispersive X-ray Fluorescence (EDXRF)

Aims: This study was to analyse pegmatite rock samples in order to determine the concentrations of naturally occurring radionuclides and heavy metals present in the samples.

Study Design: The samples were analysed using non-destructive Energy Dispersive X-ray fluorescence (EDXRF) spectrometer.

Place and Duration of Study: This work was carried out at the Centre for Energy and Research Development (CERD), Obafemi Awolowo University, Ile- Ife, Osun State, Nigeria between September 2016 and June 2017.

Methodology: In this study, analysis of ten randomly selected rock samples were carried out using EDXRF to determine the concentrations of the naturally occurring radionuclides and heavy metals presence. The elements detected were divided into three groups which include: radionuclides, major and minor elements which were related together using the Pearson correlation coefficient.

Results: The EDXRF analysis confirmed the presence of U (1.54 %), Th (0.40 %), and K (7.85 %) with concentrations higher than their permissible world values of 0.0002.8 %, 0.0007.4 %, and 1.3 %, respectively. The samples contained seven major elements (Fe, Mn, Pb, Ti, La, Ca, and Ta) and fourteen minor elements including some heavy metals (Zn, Sr, Zr, Cr, Nb, Mg, Ce, Re, Hf, V, Al, Nd, Sc, and Y). The results showed a large quantity of Fe with an average value of 37.67 %.

Conclusion: The presence of natural radionuclides and toxic metals like Cr, Pb, and Mn in significant quantity in some of the samples is of serious environmental and public concern. There is an absolute possibility that the heavy metal and the radionuclides find their ways into the natural ecosystem as a result of anthropogenic activities such as mining. This could pose miners, dwellers, and the general populace to a serious health risk.