Assessment of environmental and radiological health hazards due to heavy metals and radionuclides contents in utility water reservoirs' sediments

Abstract

Heavy metals and natural radionuclides in sediments of Awara and Osse reservoirs, Ondo State, Nigeria have been measured using X-ray fluorescence and γ-ray spectrometry techniques. Heavy metals detected in the two reservoirs include K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Ba, Pb and Th. The average concentrations of the measured heavy and trace metals in the sediment of Awara dam vary as Fe>K>Ca>Mn>Ti> Sr>Cr>V>Rb>Zn>Ni>Cu while those of Osse dam vary as Ba>K>Fe>Ca> Mn>Sr>Ti>V>Rb>Cr>Zn>Ni>Th>Pb>Cu. Geoaccumulation index and enrichment factor evaluation of potentially toxic heavy metal contents in both reservoirs revealed that the two reservoirs are uncontaminated with hazardous heavy metals. Naturally occurring radionuclides (40K and 232Th) detected in the two reservoirs show values that are higher than their mean crustal value, while 226Ra is lower than the world mean crustal value. There is little or no ecological or radiological risk associated with the sediment of the two reservoirs.