Speciation of Cr, Fe, Cu, Pb in the surface and under water sediment of Trans–Ekulu river, Enugu State, Nigeria

Abstract

This study investigated the distribution and speciation of Cr, Fe, Cu and Pb between the surface and bottom sediments of Trans-Ekulu river Enugu, Nigeria, using flame atomic absorption spectrometric technique. The results showed that the concentrations of Fe vary significantly in the two sediment samples. Iron was observed at elevated concentrations in exchangeable, carbonate bound and Fe-Mn oxide bound fractions (76.04 to 81.03 µg/g). Very low concentration in comparison was recorded at the organic matter bound fraction (5.01 µg/g). This observation was in contrast to bottom sediment where Fe recorded an elevated concentration at the organic matter bound fraction (73.01 µg/g) and reduced concentrations at the exchangeable and carbonate bound fractions (2.01 µg/g and 4.02 µg/g) respectively. The result also indicated an increase in Cr concentrations at Fe-Mn oxide fraction of the bottom sediment (14.04 µg/g) compared to the surface sediment where Cr was not detected at the Fe-Mn oxide phase. Copper and Pb were generally not detected in the fractions studied. However, Cu was observed at Fe-Mn oxide phase for the bottom sediment (25.01 µg/g) and reduced phase for the surface sediment (7.01 µg/g). These results indicate an objectionable values in the concentration of the parameters analysed. Keywords : Speciation, metals, Enugu, sediments, AAS.