title: Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques.
abstract: Trace metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources.
authors.affiliation: Environmental Chemistry Unit, Department of Chemistry, Covenant University, Ota, Nigeria.
authors.forename: Nsikak U
authors.initials: NU
authors.lastname: Benson
authors.affiliation: Faculty of Marine Sciences, University of Calabar, Calabar, Nigeria.
authors.forename: Francis E
authors.initials: FE
authors.lastname: Asuquo
authors.affiliation: Environmental Chemistry Unit, Department of Chemistry, Covenant University, Ota, Nigeria.
authors.forename: Akan B
authors.initials: AB
authors.lastname: Williams
authors.affiliation: Department of Microbiology, University of Uyo, Uyo, Nigeria.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Essien
authors.affiliation: Department of Chemical Science, Ritman University, Ikot Ekpene, Akwa Ibom State, Nigeria.
authors.forename: Cyril I
authors.initials: CI
authors.lastname: Ekong
authors.affiliation: Department of Chemistry, University of Uyo, Uyo, Akwa Ibom State, Nigeria.
authors.forename: Otobong
authors.initials: O
authors.lastname: Akpabio
authors.affiliation: Industrial and Environmental Chemistry Unit, Department of Pure and Applied Chemistry, Ladoke Akintola, University of Technology, Ogbomoso, Nigeria.
authors.forename: Abaas A
authors.initials: AA
authors.lastname: Olajire
mesh_terms: D016000:Cluster Analysis; D003300:Copper / Q000032:analysis; D004463:Ecology; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods; D019015:Geologic Sediments / Q000032:analysis*; D019216:Metals, Heavy / Q000032:analysis*; D009532:Nickel / Q000032:analysis; D025341:Principal Component Analysis; D014131:Trace Elements / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D019216:Metals, Heavy; D014131:Trace Elements; D014874:Water Pollutants, Chemical; D003300:Copper; D009532:Nickel