HEAVY METALS IN CANNED FISHES STORED IN VEGETABLE OIL MARKETED IN BENIN CITY, EDO STATE, NIGERIA.  

Introduction

Canned fishes are widely consumed by an average Nigerian, especially children, and fish also constitute more than 60% of the protein intake in adults especially in the rural areas (Adeleye, 1992). Fish is highly perishable; method of capture, handling, storage and processing all contributes to rapid deterioration of its quality and limiting the shelf life of the product (Sallem, 2007). The objectives of this study was to determine the heavy metal content levels of the different brands of canned fish products stored in vegetable oil.

Method

During this study, five heavy metals (Fe, Zn, Mn, Ni and V) in seven canned fish brands stored in vegetable oil which are sold in Benin-city were determined using Atomic Absorption Spectroscopy (AAS). The samples were analysed between January - September, 2015.

Result

Iron (Fe), Zinc (Zn), Manganese (Mn), Nickel (Ni) and Vanadium (V) were detected in all canned fish samples except for V which was below detection level. The heavy metal content expressed in mg/kg, varied from 2.21-21.38mg/kg for Iron, from 5.41-52.35mg/kg for Zinc, 0.05-0.72mg/kg for Manganese, 0.42- 7.00mg/kg for Nickel, from 0.02-0.16mg/kg for Vanadium. The contents of Iron, Zinc, Manganese, Nickel and Vanadium were not significantly different (P>0.05) except for Nickel content in the different canned fish samples when compared to the permitted level according to FAO, WHO and EU legislation. Comprehensive and intermittent monitoring of heavy metals in canned fish is needed to assess the safety of these products with respect to human health. Also there should be reduction of the consumption of canned fish as frequent consumption may result in bioaccumulation of the metals and increase health risks. And that the government should enforce laws that will prevent the dumping of untreated wastes into the aquatic environment.