Full Length Research Paper
Amin O. Igwegbe, Charles A. Ne
Abstract
This study was designed to evaluate the effects of season and a fish preservation process  namely salting and sun-drying (using a solar-tent-dryer) on the levels of lead, cadmium, mercury and arsenic in the fresh and processed fish species: Tilapia nilotica (Tilapia), Synodontis guntheri (Kurungu), Heterotis niloticus (Bargi), and Clarias anguillaris (Catfish). The objective was to determine whether the preservation method may lead to an increase in the levels of the metals in the treated fresh fish samples harvested from three different locations during the dry and rainy seasons. Samples were wetdigested, and the heavy metals were quantified with an AAS (for lead and cadmium) and ICP-OES (for mercury and arsenic). Results indicated significant (P0.05) differences between the levels of the heavy metals in fresh fish harvested during the dry and rainy seasons on one hand and the concentrations of the metals in salted and sun-dried samples on the other hand. Cadmium and arsenic were the lowest recorded metals in both the fresh and treated fish samples during the two seasons and in all the locations. The sequence of the heavy metal concentrations in all the fish samples was Pb>Hg>Cd>As. The heavy metal concentrations in the fresh and salted sun-dried fish from all the locations were however lower than the internationally recommended threshold levels. It was concluded that many factors including season during growth of fish, handling and processing, could influence the levels of toxic heavy metal contamination in fresh fish and processed product; and that, although salt does have its limitations and disadvantages, its utilization conditions must be optimized to provide safe food for consumers, at the same time addressing their needs and concerns.