Analysis of sediment samples for some trace and major metals from Okaba coal mine in Kogi State, Nigeria by energy-dispersive x-ray fluorescence spectrometry: Effect of seasonal variations on the concentrations of these metals

Abstract

Coal sediment samples from Okaba coal mine in Kogi State, Nigeria, were subjected to analysis for some metallic and non-metallic compositions. Of 35 elements determined by energy-dispersive X-ray fluorescence  spectrometry, a number of anomalously high levels were recorded. Elements determined are Al, Si, P, S, K, Ca, Ti, Cr, Mn, V, Fe, Ni, Cu, Zn, Rb, Zr, Ru, Ba, Sr, Y, Se, Os, Bi, Sb, Pb, Mg, Na, Se, Br, As, Cl, Au, Nb, Hg and W. Most of the known or potential metal contaminants are included in this list. The extent of contamination of sediments by metals analysed is greatest for Fe and then in decreasing order Al, K, Ti, Ru, Zr, Sb, Pb, Ba, Cu, V, Mn, Sr, Cr, Y, Bi, Rb, As, Au, Sc and Os. Results are presented. It was observed from seasonal variations that flooding and leaching contributed to the increase in the concentrations of the metals studied at the downstream. Metals such as Mg, Na, Se, Os, Bi, Nb, Hg and W were not detected at all levels. Thus the coal mine contributed greatly to these concentrations in all the sediment samples. Seasonal variations play an important role in the concentrations of the metals studied. This was evident at the downstream part of the sediment samples were elevated concentrations were observed.

Keywords: coal, trace metals, ED-XRF, sediments, seasonal variation.