Heavy metal mobility, bioavailability, and potential toxicity in sediments of the Korle lagoon in Ghana

Abstract

This study aimed to identify the mobility, bioavailability, and potential toxicity of heavy metals (HM) in sediments of the Korle lagoon using metal partition. Sediments were analysed using the BCR (Bureau of reference) method. As (60%), Pb (50%), Zn (57%) and Fe (40%) were found in high concentration in the ion exchangeable fraction. The oxidisable fraction was dominated by Cu (51%), Cd (95%), Cr (61%), Ni (63%), As (35%), Fe (21%), Hg (30%), Pb (19%) and Zn (11%). The reducible fraction was dominated by Zn (29%), Pb (24%) and Hg (19%). The residual fraction was dominated by Hg (49%) and Fe (34%). PCA was used to identify pH and organic matter as the most important factors controlling the mobility and bioavailability of HM in the sediments. Arsenic, Pb, Zn and Fe were found to have the highest mobility. Chromium, Cu and Ni have medium mobility. Hg has low mobility. Most of the HM show potential bioavailability and toxicity.