Abstract for Post: Chemical Speciation and Risk Implications of Some Heavy Metals in Sediment Profiles of Urban Stream Stretches, Yenagoa City, Bayelsa State, Nigeria
Author(s): Leizou, Kaywood Elijah and Azibaola Kesiye Inengite
Chemical speciation of selected Heavy metals using sequential extraction procedure was performed in the sediments collected from urban stream stretches, Yenagoa City, Bayelsa State, South-South, Nigeria, in order to ascertain their mobility, bioavailability and human health risk implications. Speciation study applying the five-step sequential extraction scheme revealed that Pb and Mn in sediment prevail mostly in exchangeable, carbonate and Fe/Mn-oxide fractions. Cu, Zn and Cr were more prevalent in organic and residual fractions, while Cd was below detection limit. Eco-toxicological assessment of the stream sediments using the mobility factor and percentage bioavailability reveals the following sequence: Mn >Cu>Zn >Pb >Cr>Cd and Cr>Zn>Mn>Pb>Cd>Cu respectively. The heavy metal contamination in sediments was further determined using sediment quality guidelines developed for metals in freshwater ecosystems (ecotoxicological sense of heavy metals) reveals that the studied heavy metals in sediments of urban stream stretches of the Yenagoa City, do not exceed consensus-based TEC values which can lead to adverse impact on the ecosystem and human health risk implications.