Evaluation of Heavy Metals in Stream Sediments from Abakaliki Pb – Zn Ore Mining Areas of Ebonyi State, Nigeria

Abstract

This research is an assessment of toxic metals in stream sediments from the Abakaliki Pb-Zn mine area of Ebonyi state. Heavy metals in stream sediment samples were analysed using Atomic Absorption Spectrometer (AAS). Physicochemical parameters were determined show that pH is generally low (3.65) resulting from the dissolution of the sulphide Ore. The heavy metal mean trend indicates that Fe > Zn >Pb> Cr >Cu > Ni > AS > Cd in the stream sediment samples. Fe, Zn, Cu, Pb and Cr were observed to be high. The variations for the heavy metals suggest that mining operation is responsible for the distribution and redistribution of chemical elements. The values of contamination factor for the stream sediment indicate moderate contamination for Cd, As and Ni while Fe, Zn, Pb, Cu and Cr show very high contamination. The result of enrichment factor (EF) using Fe concentration as normalizing value show that Ni, Cd, Cr, As, and Cu have depletion to mineral enrichment while Pb and Zn show moderate enrichment. The result of the Correlation analysis and principal component analysis (R-Mode and Q-mode) applied to the data analysis show that Zn, Pb, Cd, Cu, and Cr heavy metals originated from similar sources but may have been influenced by mining operation while Ni and As are attributed to a geogenic source. Proper sewage disposal practice and soil remediation are recommended.