Gobal Advanced Research Journal of Environmental Science and Toxicology (GARJEST) ISSN: 2315-5140
October 2012 Vol. 1(7), pp. 183-189
Copyright © 2012 Global Advanced Research Journals
Full Length Research Paper
Heavy metal concentration in some fishes (Chrysichthys nigrodigitatus, Clarias gariepinus and Oreochromis niloticus) in the Great Kwa River, Cross River State, Nigeria
Fidelis Bekeh Ada1*, Edet Ekpenyong2 and Bayim Peter-Robins Bayim3
1Department of Fisheries and Aquatic Sciences, Faculty of Agriculture and Forestry, Cross River University of Technology, Obubra Campus, Cross River State, Nigeria.
2Department of Zoology and Environmental Biology, Faculty of Sciences, University of Calabar, Cross River State, Nigeria.
3Department of Chemical Science, Faculty of Sciences, Cross River University of Technology, Calabar Campus, Cross River State, Nigeria.
*Corresponding Author E-mail: firstname.lastname@example.org
Accepted 13 October, 2012
Heavy metal concentration in the tissues of three important food fishes namely: Chrysichthys nigrodigitatus, Clarias gariepinus and Oreochromis niloticus were investigated. This was aimed at finding their fitness for consumption become fish is usually at the apex of aquatic food chain capable of bioaccumulating heavy metals. Specimens were purchased once a month from the local fishers at Ekpene Esuk Essighi and Esuk Mba landing sites. Gills, kidney, liver, stomach and muscles were washed and oven dried at 105 0C until constant weight. Heavy metals concentrations were obtained spectophotometrically using Perkin-Elmer Analyst 300 Atomic Absorption spectroscopy (AAS). A one way Analysis of variance (ANOVA) was used to test the difference in concentrations of heavy metals in the different tissues. Differences in means were separated by the use of Duncan’s multiple range tests (DMRT). In Chrysichthys, zinc was highest in stomach (177.70+1.48 mg/kg) and lowest in muscle (32.37+1.00 mg/kg) Chromium was not detected in muscle but highest in gills (0.34+0.01 mg/kg). Cadmium ranged from 0.004+0.001 mg/kg in muscle to 0.02 in kidney. Nickel was 0.00+0.00 mg/kg in kidney to 0.012+0.001 mg/kg in liver. Lead was high in the gills of Chrysichthys. Clarias has the highest concentration of zinc in gut (99.43+ 0.87 mg/kg and lowest in muscle. Chromium and Nickel were the least concentrated metal in tissues of Clarias. Cadmium was high in the gills (0.06+0.01 mg/kg) and lowest in muscle (0.002+0.001 mg/kg). Lead had the highest concentration in gills (0.044+0.014 mg/kg) and 0.001+0.001 mg/kg in muscle. In Oreochromis, lowest zinc was in muscle (28.41+0.58 mg/kg) highest in kidney (66.48+ 0.002 mg/kg) Chromium was not detected in any tissue. Cadmium was found in gills (0.002+0.001mg/kg), kidney (0.05+0.001 mg/kg) and liver (0.273+0.01mg/kg). Nickel was found in liver in trace amount only. Lead was not present in muscle but highest in gills (0.213+0.025 mg/kg). Of all the tissues, muscle was the one with least concentration of metals. These concentrations were allowable in food fish.
Keywords: Chrysichthys, Clarias, Oreochromis, Heavy metals, Great Kwa River.
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- Edet Ekpenyong on Google Scholar
- Edet Ekpenyong on Pubmed
- Bayim Peter-Robins Bayim on Google Scholar
- Bayim Peter-Robins Bayim on Pubmed