Seasonal Variation of Metal Concentrations in Catfish, Blue Crab and Crayfish from Warri Coastal Water of Delta State, Nigeria

Abstract

The concentrations of Pb, Ni, Fe and Cd were determined using Atomic Absorption Spectrophotometer-Varian Spectral AA220 in catfish, blue crab and crayfish from Warri coastal water of Delta state. Of all the heavy metals examined, the line charts presented in Fig. 2, 3 and 4 indicate that Cd and Pb have the highest concentration while Fe and Ni have the least concentration in the three fauna considered for the experiment at both dry and wet seasons of 2008. The mean concentration values for catfish are: 0.002-2.52 mg/kg, 0.22-3.50 mg/kg, 0.002-1.48 mg/kg and 0.009-18.13 mg/kg; blue crab: 0.82-3.40 mg/kg, 0.35-2.50 mg/kg, 0.06-1.61 mg/kg and 1.62-12.88 mg/kg and crayfish: 0.22-8.00 mg/kg, 0.01-2.25 mg/kg, 0.004-0.55 mg/kg and 0.038-18.13 mg/kg for heavy metals of Pb, Ni, Fe and Cd respectively. The concentrations of the metals determined varied from one location to another and from one specie to another. Hence, Egbokodo location has the highest Cd content in catfish while Jeddo and Ughoton locations have highest Cd content in crayfish and blue crab respectively. Lastly, the order of increasing in concentration of the metals is Fe<Ni<Pb<Cd.