Heavy Metals in Heterobranchus Longifilis (Cuvier And Valenciennes, 1840) Cultured in Earthen Ponds in Selected Communities in Warri Metropolis, Nigeria

Abstract

The concentrations of Cadmium (Cd), Copper (Cu), Lead (Pb) and Zinc (Zn) in Heterobranchus longifilis (Mean total length= 40.52 cm; mean weight=563.25 g) cultured in earthen ponds in Warri, Nigeria, were determined by Atomic Absorption Spectrometric technique in order to provide baseline data and to ascertain the suitability of such fish for consumption. The mean concentrations of metals in H. longifilis, ranged from 0.13 mg/kg for Cd in January to 72.51 mg/kg for Cu in June with significant differences (p<0.05) observed in the mean concentrations of Cu, Pb and Zn in fish between months. The mean concentrations of metals in H.longifilis, ranged from 0.12 mg/kg for Cd at Jeddo to 69.27 mg/kg for Cu at Ubeji with significant differences (p<0.05) observed in the mean concentration of Zn in fish between stations. The bioaccumulation quotient (BQ) values ranged from 0.50 for Cd at Jeddo to 37.24 for Cu at Oboroke while the hazard quotient (HQ) ranged from 0.39 for Zn to 3.43 for Pb. The maximum acceptable risk (MAR) values anged from 0.02 for Pb at Ekpan to 6.29 for Zn at Ubeji while the estimated average daily intake (EADI) of heavy metals ranged from 0.09 mg/person/day for Cd to 36.13 mg/person/day for Cu. It was concluded that Cd, Cu and Pb were the metals that presented a potential risk to the consuming public and that the heavy metal content in earthen ponds should be routinely monitored in order to keep metal levels within safe limits.Keywords: Heavy metals, Hazard quotient, Heterobranchus longifilis