ASSESSMENT OF HEAVY METALS IN WILD AND FARMED AFRICAN CATFISH CLARIAS GARIEPINUS (BURCHELL, 1822) IN SELECTED RIVERS AND FISHFARMS IN KADUNA STATE, NIGERIA
ASSESSMENT OF HEAVY METALS IN WILD AND FARMED AFRICAN CATFISH CLARIAS GARIEPINUS (BURCHELL, 1822) IN SELECTED RIVERS AND FISHFARMS IN KADUNA STATE, NIGERIA
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Date
2017-07
Authors
ONYIDOH, Henry Eric
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Abstract
The presence and bioaccumulation pattern of some heavy metal concentrations in wild and farmed African catfish, Clarias gariepinus (Burchell, 1822) muscles collected from selected rivers and fish farms in Kaduna State, Nigeria, were assessed. Fish and water samples used for the assessment were collected during the wet and dry seasons from River Kaduna, River Galma in Zaria; and from two fish farms in Sabon Tasha, Kaduna and Dakace, Zaria. Physico-chemical parameters, such as Puissance Hydrogen (pH), temperature, Turbidity etc., were also analysed. The analyses of heavy metals, Iron (Fe), Lead (Pb), Nickel (Ni), Cadmium (Cd) and Mercury (Hg), in all water and Clarias gariepinus muscle samples was carried out in the Multi-User Science Research Laboratory, Department of Chemistry, Ahmadu Bello University, Zaria, using Thermo-element Solar S4 Atomic Absorption Spectrophotometer (AAS), while the Varian Generation Accessory (VGA 77) with closed end cell was used for Hg determination. The results obtained were subjected to t-test analysis to determine the level of significance (p < 0.05) between the means, while Pearson correlation coefficient was employed to determine the relationships. pH was highest in River Kaduna during the wet season, in the upstream (7.04), while there was a dip in the downstream (6.67) during the dry season. Seasonal variations in temperature were evident, as the ranges obtained in the rivers were from 27.03°C – 30.68°C and the farms ranged from 23.76°C – 27.42°C, which were within World Health Organization (WHO) recommended threshold (30°C – 36°C). Dissolved Oxygen (DO) varied widely in the rivers (5.11mg/l – 7.04mg/l) as well as in the farms (9.29mg/l – 10.74mg/l). Total dissolved solids (TDS)obtained in this study were all very high (Rivers: 54.91mg/l – 82.09mg/l, Farms: 28.43mg/l – 42.03mg/l), but were all lower than the WHO standardindicativeofportability (1000 – 1600mg/l). Heavy metal concentrations in water samples and heavy metal bio-accumulation in both wild and farmed C. gariepinus muscles showed irregular distributions with descending order of:Fe >Pb>Hg>Ni > Cd. Fe
levels were the highest in both rivers water samples (3.23mg/l), closely followed by Pb (0.78) and Hg (0.69mg/l), while the farms also had Fe as the dominant element (1.31mg/l), with Pb (0.26mg/l) and Hg (0.09mg/l), respectively. Both water bodies had Ni concentration (0.2mg/l) higher than the WHO limits of 0.02mg/l, while the farms‟ concentration (0.03mg/l) was slightly higher than WHO threshold limit. In the muscle of C. gariepinus, Fe concentrations were also high in rivers (3.53mg/kg), while the Farms was 1.44mg/kg, all above the FAO recommended limit (0.5mg/kg) in fish. Generally, only Cd didnot exceed the maximum permissible limits in the tissues ofC. gariepinus. However, with Fe, Hg, Pb and Ni all higher than the acceptable limits, most especially in the rivers, this could pose a serioushealth risk to consumers. Thus, a close periodical and regular monitoring of heavy metal pollution in the water bodies is strongly advocated.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF MASTER OF SCIENCE (MSc.) IN EDUCATIONAL BIOLOGY
DEPARTMENT OF BIOLOGY
FACULTY OF LIFE SCIENCES
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA
Keywords
ASSESSMENT,, HEAVY METALS,, WILD,, FARMED AFRICAN CATFISH CLARIAS GARIEPINUS,, (BURCHELL, 1822),, SELECTED RIVERS,, FISHFARMS,, KADUNA STATE,, NIGERIA