Levels of Zinc, Iron and Lead in Canned Fish Sold in Jos, Nigeria

Abstract

Introduction: Both nutritional metals such zinc and iron, and toxic metals, such as lead, present in food above certain permissible levels, pose danger to consumers. Fish harvested from contaminated waters tend to have high levels of these metals. Moreover, the level of contamination could be aggravated by processing and canning. Aim: In this research, we determined the extent to which zinc, iron and lead are present in canned fish commonly sold in Nigerian markets. Place and Duration of Study: This research was conducted in the Department of Science Laboratory Technology of the University of Jos, Nigeria, between the months of November, 2010 16 and May, 2011. Materials and Methods: Canned tuna and sardine produced by different manufacturers were obtained in Jos market, Nigeria. Measurement of metal concentration in the canned fish was carried out by using atomic absorption spectrometer. Results: The range obtained for the elements analyzed in µg/g (dry weight) in both the fish and fish oil are as follows: Zn, 22.06±0.05 - 216.67±0.52; Fe, 13.48±0.29 - 182.32±0.12; and Pb, 13.63±0.22 – 235.12±0.10. Conclusion: The metals levels were generally above their respective FAO/WHO recommended limits. Statistical analysis showed significant difference (p = 0.05) between the metal concentrations in canned fish from one manufacturer and the other. We recommend that further research on metal content of canned fish sold in Nigeria be done with a view to ascertaining the level of these metals ingested by the populace.