Residual Levels of Polychlorinated biphenyls (PCBs) in the Atlantic Mackerel (Scomber scombrus, Linnaeus, 1758) Marketed within a Niger Delta Community

Abstract

The residual levels of polychlorinated biphenyls (PCBs) in the Atlantic Mackerel, Scomber scrombrus (mean length 44.87 cm, mean weight 478.35 g) marketed in Asaba, Delta State, Nigeria, were determined by Gas Chromatographic (GC) technique in order to ascertain its suitability for human consumption. The summary statistics for the mean concentrations of detectable PCBs in S. scrombrus ranged from 0.04 mg/kg (PCB 153) to 0.65 mg/kg (PCB 126), with a total of 0.93 mg/kg while the mean concentrations of PCBs in S. scrombrus by market ranged from 0.02 mg/kg (PCB 153) at Cable market to 0.82 mg/kg (PCB 126) at Abraka market with no observed significant difference (p>0.05) in the mean concentrations of PCB 153 and PCB 169 in fish between markets. The toxicity quotient (TQ) values for PCBs in S. scrombrus ranged from 0.02 (PCB 153) to 0.33(PCB 126) while the estimated daily intake (EDI) values in mg/person/day for PCBs ranged from 0.00072 (PCB 138) to 0.026 (PCB 126). A toxic equivalency (TEQ) value of 0.0656 was recorded with PCB 126 having the highest Sub-TEQ value of 0.065 while the total PCB content in S. scrombrus according to market ranged from 0.67 mg/kg (Cable market) to 1.20 mg/kg (Abraka market). The observed PCB levels in fish fell below International threshold values indicating suitability for human consumption. However constant monitoring of this aquatic species for hazardous levels of PCBs was highly recommended.