Research Article Open Access Volume 5 • Issue 5 • 1000303 J Environ Anal Toxicol ISSN: 2161-0525 JEAT, an open access journal Open Access Research Article Olusola and Festus, J Environ Anal Toxicol 2015, 5:5 DOI: 10.4172/2161-0525.1000303 *Corresponding author: Olusola JO, Department of Chemistry, Federal University of Technology, Akure, Nigeria, Tel: 234-806-644-7549; E-mail: layinkx@gmail.com/ demolaktp@yahoo.co.uk Received May 20, 2015; Accepted June 17, 2015; Published June 22, 2015 Citation: Olusola JO, Festus AA (2015) Levels of Heavy Metal in Some Selected Fish Species Inhabiting Ondo State Coastal Waters, Nigeria. J Environ Anal Toxicol 5: 303. doi:10.4172/2161-0525.1000303 Copyright: © 2015 Olusola JO, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Levels of Heavy Metal in Some Selected Fish Species Inhabiting Ondo State Coastal Waters, Nigeria Johnson Olayinka Olusola* and Aiyesanmi Ademola Festus Department of Chemistry, Federal University of Technology, Akure, Nigeria Keywords: Heavy metals; Bioaccumulation; Fish; Coastal water Introduction Fish and fshery products are generally regarded as important part of a healthy diet. In developing world, fsh and fshery products apart from being a source of cheap animal protein, are widely consumed since they have high quality protein and other essential nutrients and are low in saturated fat and contain omega 3 fatty acids. Over the last ffy years, there has been an increase in the number of chemical compounds identifed to be present in natural waters. Majority of these chemicals originate from various industrial activities and increasing urbanization facilitates their entry into rivers, lakes and ocean [1]. Ondo State is located in South Western Nigeria and has coastal areas estimated to be about 60,000 hectares. It is an oil producing state along other Niger Delta State such as Delta, Rivers, Bayelsa, Akwa Ibom etc. Te surface area of marine and brackish water resources in Nigeria covers estimated area of 233,000 km 2 [2] and the brackish-marine fshery potential has been estimated at 273,500 metric tonnes per annum [3]. Te main marine-brackish water areas in Nigeria are found along the coastal zone which are characterized by expansive estuarine lagoon and mangroves swamps fronted by beach ridge barriers this extend from Lagos lagoon through Ondo State coaster waters to the Niger Delta in the South-south of Nigeria. Sustainability of fsheries resources in the coastal waters is now threatened by the introduction of oil into the ocean via oil spillage for the great majority of species which spend their earliest stages near coast, estuarine, brackish or freshwater. Exploration and exploitation activities of oil companies such as Shell, Chevron, Texaco etc. in the coastal region of Ondo State, Nigeria is one major way by which the natural coastal waters of Ondo State, Nigeria is being polluted. Oil spills could occur as result of release of crude oil from tankers, ofshore platforms, drilling rigs and well, as well as spills of refned petroleum product (such as gasoline, diesel etc.) and their by-products and heavy fuel used by large ship. Oil spillage into water afects the ecosystem and its component negatively. Among animal species, fsh are the inhabitant that cannot escape from the detrimental efects of these pollutants. Fish are widely used to evaluate the health of aquatic ecosystems because pollutants build up in the food chain and are responsible for adverse efects and death in the aquatic systems [4]. Te major sources of heavy metals in water especially in the oil producing areas (like the study area) include crude oil, drilling fuids, or mud, agricultural activities, domestic wastes and natural sources that make up the background concentration. As heavy metal cannot be degraded, they are deposited, assimilated or incorporated in water, sediments and aquatic animals and thus causing heavy metal pollution in water bodies [5]. Terefore, heavy metals can be bioaccumulated and biomagnifed via the food chain and fnally assimilated by human consumers resulting in health risks [6]. Arius latisculatus known as roughhead sea catfsh belongs to the family Ariidea. Tey live mainly in marine waters, freshwater and brackish waters. Ariidea catfsh are found in shallow temperate and tropical seas around the coastlines of Africa, North and South America, Asia and Australia. Cynoglossus browni, commonly known as the Nigerian tonguesole is a species of tonguefsh. It is commonly found in Eastern Atlantic Ocean of the coast of West Africa. Caranx lugubris and Caranx senegallus referred to as Black jack and Senegal jack respectively, belongs to the jack family Carangidae. Te species is distributed through the tropical waters of the eastern Atlantic Ocean, to the West African coast. Carangidae are predatory fshes, taking a variety of small fshes, crabs and shrimps Sardinella aurita is a genus of fshes in the family Clupeidae, Sardinella species are generally coastal, schooling, marine fsh. Juveniles are ofen found in lagoons and estuaries, and adults are more common Abstract The distribution and level of six heavy metals viz: Cr, Cd, Pd, Cu, Zn, and Ni in different organs gill, head, bone, muscle and eye of fve fsh species Arius latisculatus, Cynoglossus browni, Caranx lugubris, Sardinella aurita, Caranx senegallus, and associated water collected from the coastal waters of Ondo State, Southwestern Nigeria were investigated in this study. The concentrations of Zn (0.10-0.36 mg/kg), Cu (0.18-0.27 mg/kg), Ni (BDL-0.01 mg/kg) and Cr (0.04-0.63 mg/kg) found in the water samples were within the Maximum Permissible Level (MPL), while higher concentrations above the MPL were recorded for Cd (0.08-0.19 mg/kg) and Pb (0.34-0.79 mg/kg). Zn was the most abundant heavy metals found in all fsh species organs investigated. Higher concentrations of the metals were recorded in the gills and eyes compared to other organs in most of the fsh species. While the concentration of Zn (0.28 mg/ kg-4.14 mg/kg), Cu (BDL-5.72 mg/kg), Ni (BDL-0.01 mg/kg), and Cr (BDL-3.41) in the fsh tissues were within the Maximum Allowable Level (MAL) for a food source, the fndings of this study Cd (BDL-3.18 mg/kg) and Pd (BDL-1.14 mg/kg) showed values exceeding the maximum allowable level, thus constituting potential health hazard to consumers of these fsh species. Transfer factors of most metals in fsh from water were greater than or equal to 1 suggesting bioaccumulation of the metals by the fsh from water column, while distribution of the heavy metals in the different fsh parts were organ specifc. Journal of Environmental & Analytical Toxicology J o u r n a l o f E n v i r o n m e n t a l & A n a l y t i c a l T o x i c o l o g y ISSN: 2161-0525