TITLE:
Assessment of Heavy Metal Contamination in Sea Bed Sediment of the Bight of Bonny, Southern Atlantic Coast of Nigeria Using Index Model Analysis
AUTHORS:
Justin Nnaemeka Okorondu, Elechi Owhoeke, Bridget Edewede Diagi, Joseph Ikechukwu Nwachukwu, Lucy C. Izunobi
KEYWORDS:
Pollution Assessment, Heavy Metal, Sediment, Enrichment Factor, Geo-Accumulation Index, Pollution Load Index
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.9 No.12,
December
31,
2021
ABSTRACT: The
heavy metal contamination status of Bight of Bonny sea bed sediment was investigated. Sediment samples were collected
from eleven locations grouped into three stations. The samples were analyzed to
determine the heavy metals (Fe, Pb,
Ni, Zn, Mn, Co, Cd, Cu, Cr) concentration using atomic absorption
spectrophotometer. Index model analyses, such as geo-accumulation index
(I-geo), Enrichment factor (EF), and Pollution load index (PLI) were used for
pollution assessment of sea bed sediment. The most predominant heavy metals in
the upstream sediment were Fe; 13.57 ± 1.838 mg/kg, cobalt; 7.987 ± 3.550
mg/kg, and Ni; 1.020 ± 0.802 mg/kg, midstream sediment were Fe; 8.554 ± 3.010
mg/kg, Co; 8.520 ± 4.00 mg/kg, and Ni; 1.140 ± 0.879 mg/kg, while the
downstream sediment result had Fe; 11.12 ± 3.825 mg/kg, Co; 7.275 ± 1.700
mg/kg, and Cd; 1.025 ± 0.159 /kg. The I-geo results indicate that Cu, Mn, Pb,
Cr, Fe, Zn, Ni, and Co were in their background concentrations while Cd had
I-geo > 3 which implies a
moderately or heavily polluted environment.
The EF indicates metal enrichment from anthropogenic sources for Co, Ni, Pb, Cd, Cu, and Cr while Fe and Mn
predicate biogenic origin. The PLI of the heavy metals in the three sample
stations of sea bed sediment was found to be generally low (cumulation index strongly suggest the Bight
of Bonny sea bed sediment contamination by Cd from anthropogenic sources.