ASSESSMENT OF HEAVY METAL CONTAMINATION IN NTSINI RIVER SEDIMENTS FROM THE COASTAL PROTECTED AREA OF LIBREVILLE, NORTHWEST GABON

An investigative study was conducted to determine the heavy metal contamination in sediments from the Ntsini River in the protected area Akanda National Park to Libreville, Gabon. A total of twelve sediment samples were collected from four locations (Ngwamba, Moka, Pages and Nendé). Sediments were analyzed for the six selected metals: Cd, Cr, Cu, Ni, Pb, and Zn using an Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). The high metal concentrations in the sediments were as follows: Zn > Cr > Ni > Pb > Cu > Cd. The highly significant positive Pearson correlations between the elements Cr, Cu, Ni, Pb and Zn indicate a common anthropogenic source of these metal elements. The CF shows an enrichment at all site for the metals Cd, Pb, and Zn. However, the CD indicates an exceptional Nendé station with moderate contamination for Cd. In this work, the results reveal low ecological risks (RI) for the metal Cr, Cu, Pb, Zn, and Ni in all stations, only Cd presents a moderate ecological risk in two stations: Ngwamba and Nendé. Therefore, effective mitigation strategies in response to metal contamination relevant to the Ntsini River in the Akanda National Park in Gabon are required to protect water quality and the health of local communities.