Biological Evidence 2018, Vol.8, No.3, 21-31
21
Research Article Open Access
Environmental Risk Assessment of Heavy Metals in Sediment of Nun River
around Gbarantoru and Tombia Towns, Bayelsa State, Nigeria
Ogaga Augustine Aghoghovwia
1
, Sylvester Chibueze Izah
2
, Faith Ayakpo Miri
1
1 Department of Fisheries and Aquatic Studies, Faculty of Agriculture, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria
2 Department of Biological Sciences, Faculty of Science, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria
Corresponding author email:
Biological Evidence, 2018, Vol.8, No.3 doi:
10.5376/be.2018.08.0003
Received: 08 Apr., 2018
Accepted: 21 May, 2018
Published: 01 Jun., 2018
Copyright © 2018
Aghoghovwia et al., This is an open access article published under the terms of the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Aghoghovwia O.A., Izah S.C., and Miri F.A., 2018, Environmental risk assessment of heavy metals in sediment of Nun River around Gbarantoru and
Tombia Towns, Bayelsa State, Nigeria, Biological Evidence, 8(3): 21-31 (doi:
10.5376/be.2018.08.0003
)
Abstract
This study evaluated the environmental risk assessment of sediment heavy metals of Nun River at Gbarantoru and
Tombia town in Bayelsa state, Nigeria. Sediment samples were collected in triplicate from three locations (viz: Location A around oil
and gas installations, B- Gbarantoru and C- Tombia town). The samples were dried, processed and heavy metals concentration was
determined using atomic adsorption spectrometry. Heavy metals results in the sediment ranged from 0.005 – 0.012 mg/kg cadmium,
0.001 – 0.003 mg/kg chromium, 0.001 – 0.002 mg/kg cobalt, 0.001 – 0.032 mg/kg nickel, 0.007 – 0.017 mg/kg lead, 0.082 – 0.126
mg/kg zinc and 0.138 – 0.314 mg/kg iron. There was significant variation (P<0.05) among the different various locations. The heavy
metals showed positive significant correlations (P<0.05). The results showed low to moderate risk for contamination factor, degree of
contamination and pollution load index; low to moderate contamination for index of geo-accumulation. Over 50% of the heavy
metals in the various locations had positive quantification of contamination, which suggest pollution due to anthropogenic activities.
On the overall, the ecological risk was within low risk. Hence, there is the need for sustainable management of anthropogenic
activities that could impact on water and sediment quality.
Keywords
Anthropogenic activities; Contamination; Ecological risk assessment; Nun River
Background
The aquatic ecosystem is a habitat to several species of fish including shelled and fin fishes (Ogamba et al.,
2017a). In the coastal region of Nigeria, especially in Bayelsa state, the aquatic ecosystem is the major recipients
of municipal wastes as well as sewage (Izah and Angaye, 2016a; b; Seiyaboh and Izah, 2017a). Authors have
variously reported that pier toilet system are built in surface water system in Bayelsa state (Agedah et al., 2015;
Ogamba et al., 2015a; Seiyaboh et al., 2017a; Kigigha et al., 2018). Wastewater resulting from bathroom is also
channeled directly to the surface water resources (Epie creek) in Bayelsa state (Ben-Eledo et al., 2017a; b).
Surface water equally receives waste resulting from slaughterhouse activities in Bayelsa state (Ogamba et al.,
2015b; Seiyaboh and Izah, 2017b). Agricultural activities are another indirect cause of water pollution. Remains
of empty cans of herbicides, and runoff from fields, where chemical fertilizers were applied end up in nearby
aquatic ecosystem.
In addition, several oil and gas installations are found in the Niger Delta region. Activities such as dredging,
canalization, oil and gas exploration on water are some of the activities that could lead to variation in aquatic
ecosystem. Ohimain et al. (2008) reported variation in surface water heavy metals due to dredging. Angaye et al.
(2015) reported effects of wastes leachate on heavy metals level in some dumpsites aligning surface water.
Typically, heavy metals in the environment are majorly due to anthropogenic activities and to lesser extent by
natural effects (Ogamba et al., 2017a). Authors have variously reported that heavy metals are metalloid with
relative high atomic weight and specific gravity of ≥ 5 cm
3
(Idris et al. 2013; Izah et al., 2016, 2017a; Izah and
Anagye, 2016a). Heavy metals have the tendency to persist in the environment and bioaccumulate in living things
(Izah and Angaye, 2016a). Some of heavy metals including manganese, chromium, nickel, cobalt, iron, copper,
