Geochemical characterization of soil samples from gold mining areas using PIXE spectroscopy

Particle-induced x-ray emission (PIXE) spectroscopy has been used to characterize soil samples from two relatively old gold mine sites (Iperindo and Itagunmodi) in the Ilesha schist belt of Southwestern Nigeria. This is with a view to identifying the indicator or pathfinder elements of gold for fingerprinting and toxicity potential assessment purposes. Average elemental concentrations of 19 major, minor, and trace elements were determined, and the geochemical data of Mn, Ni, Cu, Zn, Ag, As, Pb, and Au together with multivariate factor and cluster statistical analyses allowed to identify As and Ag as the pathfinder elements of gold. The high concentration of the determined pathfinder elements (As and Ag) as well as other toxic metals (Pb and Cu) implies a relatively high metal contamination risk to the miners and the ecosystem. The major hazard is represented by the abandoned mining wastes, pits, and ponds, already serving as fish ponds.