Heavy Metal Pollution Assessment Using Energy-Dispersive X-ray Fluorescence and Multivariate Statistical Approach of Soil from Phosphate Ore Sites, Southern Region of Togo

Optimization of different types of exposure to workers, public, and vegetation is a major issue for several institutions. The main exposure is due to the activities related to various ores of the subsoil such as phosphate which generates heavy metals during its exploitation. This study used the energy-dispersive X-ray spectrometry to investigate the heavy metal pollution that affects life on earth. Fifteen different heavy metals were detected in soil samples from sites dedicated to phosphate ore activities in southern Togo. Results showed that the concentrations of the different heavy metals decreased in the following order: Ca > Fe > K > Ti > Sr > Zn > Zr > Y > Ni > Cu > Pb > U > Br > Rb > Th. Cadmium was not detected while lead remained the most toxic element with a maximum level of 52.4 mg kg −1 . Basic statistics depicts strong positive correlations between Ni, Cu, Zn, and Fe which shows that their respective concentrations increased together. Principal component analysis was used to categorize all these data into three groups using two principal axes which recover 88.06% information. The geoacumulation index from Hahotoé-Kpogamé-Kpémé soil samples varies from class 0 to class 4 displaying that these areas are moderately polluted and was mainly due to Pb metal concentration. The potential ecological risk levels vary from 157 to 385, which corresponds to moderate and considerable levels. Therefore, these areas could be assumed to be safe regarding these levels. The moderate level observed on these various sites does not present a warning sign but should lead the legislators to establish routine monitoring in order to detect any change in the level of pollution due to heavy metals.