Analysis of Heavy Metal Concentrations in Smoked Fish from the Major Food Markets in the Accra-Tema Metropolis

Abstract

Introduction: Heavy metals contaminate soils, water bodies, and also the ambient environment. Fish could be contaminated by heavy metals through pollution of water bodies, as a result of industrial discharge, agricultural run-offs, mining activities, and weathering of rocks. Many of the food markets in Ghana are open markets where foodstuffs are usually displayed in the open, often exposed to the environment. Processed fish, especially smoked fish is a major source of protein and a delicacy in Ghana. Smoked fish, as in other foodstuffs is sold on flat trays and open baskets, which results in direct exposure to the environment. Contamination of fish may occur at source (in aquatic environment), or through ambient exposure to elemental heavy metal dust. Objective: To assess the concentrations of Arsenic (As), Mercury (Hg), Lead (Pb), and Nickel (Ni) in smoked fish from major food markets in the Accra-Tema Metropolis. Method: Smoked fish was sampled from six (6) major food markets in the Accra-Tema Metropolis and analyzed for heavy metals (Pb, As, Hg and Ni) contamination using a Pinnacle 900T Atomic Absorption Spectrophotometer (AAS). Results: The mean concentrations of mercury and nickel were (0.365-0.738 mg/kg) and (0.47 – 0.52 mg/kg) respectively, whereas lead and arsenic were not detected. The mean concentrations of Ni and Hg were detected in all fishes sampled: Tilapia (Oreochromis niloticus), Mudfish (Clarias anguillaris), Tuna (Thunnus albacores) and Salmon (Oncorhynchus sp.) Conclusion: The study revealed that smoked fish sold on the open markets have various levels of mercury and nickel, with marine fishes recording the highest levels of these metals.