Abstract
The research determined the concentrations of Arsenic (As), Cadmium (Cd), Copper (Cu) and Lead (Pb) in the myonematic tissues of selected frozen marine fish species purchased from markets in Warri town, Delta state, Nigeria, in order to ascertain their suitability for human consumption, in the wake of paucity of data regarding the metal levels in such fish in the town, employing Atomic Absorption Spectrometric technique. The mean concentrations of heavy metals in Trachurus trachurus ranged from below detection limit (BDL) for As in all markets to 0.81 mg/kg (Cu) at Igbudu market with significant differences (P<0.05) observed in the mean concentration of Cu in fish between markets. The mean concentrations of heavy metals in Clupea harengus ranged from BDL for As in all markets to 0.60 mg/kg (Cu) at Igbudu market while the mean concentrations of heavy metals in Gadus morhua ranged from BDL for As in all markets to 0.62 mg/kg (Cu) at Igbudu market. The mean concentrations of heavy metals in Scomber scombrus ranged from BDL for As in all markets to 0.75 mg/kg (Cu) at Igbudu market with significant differences (P<0.05) observed in the mean concentration of Pb in fish between markets. The toxicity quotient (TQ) values ranged from zero (0) for As in all fishes to 1.43 (Pb) in S. scombrus. Lead was the metal of potential health significance as its mean concentration in S. scombrus was well above international thresholds. Such fish must thus be eaten with caution to avoid deleterious health effects over time.

Key words: Frozen fish, heavy metals, toxicity quotient