The Determination of Lead, Arsenic, Mercury, Cadmium Contents in Some Edible Fish Species Retailed in Ibadan, Nigeria

Objective: The objective of this present study was to measure the contributions of some toxic heavy metals; namely lead, cadmium, arsenic and chromium in some edible fishes of marine origin (seafood) to the overall dietary intake of heavy metals in Ibadan, Nigeria. Materials and Methods: The samples under investigation were popular edible fish species namely; Scomber scombrus (mackerel), Haerengula jaguana (Sardine), Gadus morhua (Stockfish) and Exocoetidae volitans (flying fish) retailed in five open markets in Ibadan Metropolis, Nigeria. Sampling involved randomly procuring frozen forms of each of the experimental sample with an average length of 33.2cm in triplicate from each of the five markets on weekly basis for a month. A total of sixty samples per variety of fish used in this study was prepared for analysis by processes of homogenization and digestion of the whole fish (after their intestines have been removed); after which their individual lead, cadmium, arsenic and chromium contents were estimated by atomic absorption spectrophotometry. Results: The results revealed mean concentrations ranges in mg/kg as follows: lead (0.24 – 1.08), arsenic (0.02 – 0.19), mercury (0.16 – 0.64), and cadmium (0.13 – 0.36) in the fish samples analyzed. The mean concentrations and the estimated tolerable weekly intake (TWI) values respectively exceeded acceptable WHO/FAO permissible and tolerable weekly limits Conclusion: It can be concluded based on the findings of this present study that dietary fishes of marine origin may significantly contribute to an overall ingestion of heavy metals by the population of Ibadan. Further investigations on this present subject matter are hereby suggested