EC Nutrition

Fish is mostly consumed in many parts of the world by human population, as it provides nutrients of high biological value. Fish is a highly perishable commodity and that is why various processing methods are applied to safeguard it for use. Most of these processing methods can predispose fish to certain heavy metals that maybe detrimental to health and well-being of the human.

There are increased global reports on heavy metals contamination of food samples especially imported fish and this phenomenon has raised lots of concerns among nutritionists and health workers, and environmental toxicologist. Hence, the aim of this research work is to evaluate the quantities of heavy metals; Lead (Pb), Cadmium (Cd), Chromium (Cr), Mercury (Hg) and Arsenic (As) present in canned fishes and selected local fish samples in Nigeria. Heavy metals were determined using UNICAM 939 Atomic Absorption Spectrophotometer at different wavelengths. The results shows that cadmium content was generally low in all the samples ranging from 0.0024 - 0.0099 ppm while the local fishes showed the highest amount ranging from 0.0074 - 0.0099 ppm. Lead content ranged from 0.017 - 0.026 ppm. The local fish samples tend to have lower lead levels while the canned fishes had higher level of lead in their tissues. The result also shows that chromium content was generally high in all the samples ranging from 0.037 - 0.058 ppm while the selected fishes show the lowest amount ranging from 0.027 - 0.031 ppm. Mercury levels were present in some selected fishes ranging from 0.0037 - 0.0046 ppm while the canned ones had mercury level in the range of 0.0022 - 0.0039 ppm. The highest mercury level (0.0046 ± 0.01) was observed in sample 3, a locally consumed freshwater fish. The level of arsenic in all the samples ranged from 0.0079 - 0.015 ppm. Hazard quotient result shows that the HQ was less than 1 (< 1) generally for all the samples except for Cr level that was greater than 1 (> 1) in sample numbers 11 and 14 with HQ of 1.02 and 1.16 respectively. Therefore, the risk of exposure to majority of the tested samples shows that adverse effects are not likely to occur except for samples number 11 and 14. The levels of these heavy metals in the fish samples were below tolerable and permissible level which may not pose any harm to consumers. However, nutrition education will help to create awareness as well as protecting consumers against heavy metals bioaccumulation in the body.

 Keywords: Heavy Metals; Canned Fish; Hazard Quotient

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