Ojelade, O.C., Oyebanji, F.F., Ayantobo, O.O., Adeleke, A.J., Akinremi, S.A., Fatoke, S.O., Mafolasere, M.K. and Okeowo, V.O |
ABSTRACT
The concentrations of some heavy metals (Lead, Cadmium, Zinc and Copper) were determined in water,
sediment
and tissue (Chrysicthys nigrodigitatus) samples collected from three (3) locations in
the Lower Ogun River, Akomoje, Ogun state, Nigeria. Samples of silver catfish (Chrysicthys
nigrodigitatus) were collected monthly from fish farmers at the landing site early in the morning
from January to June 2017. The specimens were transported in an ice-chest to the laboratory
within 30 minutes of collection for subsequent laboratory analysis. The concentrations of
heavy metals were identified and analyzed using Flame Atomic Absorption Spectrophotometer. Heavy
metals in the water, sediment and tissue fluctuated throughout the sampling months, in which the
highest and lowest values were recorded during the wet and dry seasons respectively. The
concentration of different metals in water, sediment and tissues followed the same order: Zn > Cu
> Pb> Cd. The mean concentrations of heavy metals in soft tissues of Chrysichthys nigrodigitatus
were as follows: Zn: 12.341 µg/kg; Cu: 3.876 µg/kg; Pb: 2.890 µg/kg and Cd: 2.606 µg/kg. Gills
(7.606 µg/kg) of the examined fish contained the highest concentrations of all of the measured
metals, while the flesh (2.390µg/kg) retained the lowest. However, despite the level of
contamination of Ogun River by heavy metals, the level of the metals in the tissue (edible part) of
C. nigrodigitatus did not exceed the recommended permissible limit thus implying that fish in the
Lower Ogun River is considered safe for human consumption.
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Keywords: |
Heavy metal, Chrysicthys nigrodigitatus, sediment, tissue, Lower Ogun River |
