All rights reserved This work by Wilolud Journals is licensed under a Creative Commons Attribution 3.0 Unported License 43 ______________________________________________________________________ Continental J. Applied Sciences 8 (1): 43 - 48, 2013 ISSN: 1597 – 9928 © Wilolud Journals, 2013 http://www.wiloludjournal.com Printed in Nigeria doi:10.5707/cjapplsci.2013.8.1.43.48 HEAVY METAL CONCENTRTIONS IN SOME ORGANS OF AFRICAN CATFISH (Clarias gariepinus) FROM EKO-ENDE DAM, IKIRUN, NIGERIA. A. Adeyeye and P. B. Ayoola Department of Science Laboratory Technology, Ladoke Akintola University of Technology, P. M. B. 4000, Ogbomoso, Nigeria. ABSTRACT The contents of the heavy metals Fe, Zn, Cu, Mn, Pb, Cd and As were examined in the liver, heart, gills, kidney and muscles of the fish Clarias gariepinus from Eko-Ende dam in Ikirun, the capital of Ifelodun Local Government of Osun State, Nigeria. C. gariepinus is the fish of choice and the most demanded in the southwest of Nigeria. The highest metal concentrations were in the liver and the gills while the lowest was in the muscles. The general deceasing order of metal accumulation in the organs was Fe > Zn > Cu > Mn > Cd. Lead and arsenic were not detected in any organ. The values were of lower concentrations than found in many other dams and rivers in Nigeria and some other countries. The values were also lower than the FAO/WHO recommended maximum limits in fish samples, making the fish to be safe and not of any hazards for the consumers. KEYWORDS: Heavy metals; organs; Clarias gariepinus; Eko-Ende dam; Nigeria. Received for Publication: 03/11/12 Accepted for Publication: 24/01/13 Corresponding Author: INTRODUCTION The indispensable need for portable water has necessitated the need for construction of dams in various locations in Nigeria, and particularly in the southwest of the country, as reservoirs to supply portable water and thereby prevent water-borne diseases and improve the quality of life of the people. These dams also serve as sources of various species of fish for the populace. However, the contamination of fresh waters with a wide range of pollutants has become a matter of concern over the last few decades. Among the pollutants, the natural aquatic systems may extensively be contaminated with heavy metals released from domestic, industrial and other man- made activities, and through weathering of rocks and leaching of soils. Such metals may be precipitated, adsorbed on solid surface, remain soluble or suspended in water, or may be taken up by fauna and flora and eventually be accumulated in marine organisms including fish that are consumed by human beings (Adefemi et al., 2008). Compared to other types of aquatic pollution, heavy metal pollution is less visible but its effects on the ecosystem and on man are intensive and extensive (Edem et al., 2009). The fact that the toxic heavy metals are non-biodegradable and have the ability to accumulate in the environment makes them deleterious to the aquatic environment and consequently to man who depend on aquatic products including fish as sources of food. Fishes particularly are notorious for their ability to concentrate metals in their body tissues to dangerously poisonous levels (Kakulu & Osibanjo, 1988). The Minamata catastrophic disease of the 1950s and 1960s in Japan, caused by methyl mercury poisoning of people who consumed contaminated fish over a period of time is an example (Lars Jarup, 2003). Therefore, since they play an important role in human nutrition, fish need to be screened to ensure that unnecessarily high levels of the toxic heavy metals are not being transferred to man through them. African catfish (Clarias gariepinus) is of great commercial importance because it is the most widely consumed freshwater fish in Nigeria (Olaifa et al., 2004). It is therefore a good choice to study its response to environmental contaminants, particularly the heavy metals. Eko-Ende dam is a major source of portable water to Ifelodun Local Government of Osun State, in the southwest of Nigeria, comprising of Ikirun and some other major towns and several other villages. It is also a veritable source of fish for the Local Government as well as the neighbouring Osogbo, the State capital. African catfish, C. gariepinus, is the most common and the most preferred fish from the dam. However, there has been a paucity of data concerning the heavy metal contents of