ntal & A me na n ly o t ir ic v a Olusola and Festus, J Environ Anal Toxicol 2015, 5:5 n l T E o Journal of f x o i l c DOI: 10.4172/2161-0525.1000303 o a n l o r g u y o J Environmental & Analytical Toxicology ISSN: 2161-0525 ResearchResearch Article Article OpenOpen Access Access 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 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 five fish 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 fish species organs investigated. Higher concentrations of the metals were recorded in the gills and eyes compared to other organs in most of the fish 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 fish tissues were within the Maximum Allowable Level (MAL) for a food source, the findings 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 fish species. Transfer factors of most metals in fish from water were greater than or equal to 1 suggesting bioaccumulation of the metals by the fish from water column, while distribution of the heavy metals in the different fish parts were organ specific. Keywords: Heavy metals; Bioaccumulation; Fish; Coastal water of aquatic ecosystems because pollutants build up in the food chain and are responsible for adverse effects and death in the aquatic systems Introduction [4]. The major sources of heavy metals in water especially in the oil Fish and fishery products are generally regarded as important part producing areas (like the study area) include crude oil, drilling fluids, or mud, agricultural activities, domestic wastes and natural sources of a healthy diet. In developing world, fish and fishery products apart that make up the background concentration. As heavy metal cannot from being a source of cheap animal protein, are widely consumed since be degraded, they are deposited, assimilated or incorporated in water, they have high quality protein and other essential nutrients and are sediments and aquatic animals and thus causing heavy metal pollution low in saturated fat and contain omega 3 fatty acids. Over the last fifty in water bodies [5]. Therefore, heavy metals can be bioaccumulated years, there has been an increase in the number of chemical compounds and biomagnified via the food chain and finally assimilated by human identified to be present in natural waters. Majority of these chemicals consumers resulting in health risks [6]. originate from various industrial activities and increasing urbanization facilitates their entry into rivers, lakes and ocean [1]. Ondo State is Arius latisculatus known as roughhead sea catfish belongs to the family located in South Western Nigeria and has coastal areas estimated to Ariidea. They live mainly in marine waters, freshwater and brackish waters. be about 60,000 hectares. It is an oil producing state along other Niger Ariidea catfish are found in shallow temperate and tropical seas around Delta State such as Delta, Rivers, Bayelsa, Akwa Ibom etc. The surface the coastlines of Africa, North and South America, Asia and Australia. area of marine and brackish water resources in Nigeria covers estimated Cynoglossus browni, commonly known as the Nigerian tonguesole is a area of 233,000 km2 [2] and the brackish-marine fishery potential has species of tonguefish. It is commonly found in Eastern Atlantic Ocean off been estimated at 273,500 metric tonnes per annum [3]. the coast of West Africa. Caranx lugubris and Caranx senegallus referred to as Black jack and Senegal jack respectively, belongs to the jack The main marine-brackish water areas in Nigeria are found along family Carangidae. The species is distributed through the tropical waters the coastal zone which are characterized by expansive estuarine lagoon of the eastern Atlantic Ocean, to the West African coast. Carangidae and mangroves swamps fronted by beach ridge barriers this extend are predatory fishes, taking a variety of small fishes, crabs and shrimps from Lagos lagoon through Ondo State coaster waters to the Niger Sardinella aurita is a genus of fishes in the family Clupeidae, Delta in the South-south of Nigeria. Sustainability of fisheries resources Sardinella species are generally coastal, schooling, marine fish. Juveniles in the coastal waters is now threatened by the introduction of oil are often found in lagoons and estuaries, and adults are more common 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, *Corresponding author: Olusola JO, Department of Chemistry, Federal University Chevron, Texaco etc. in the coastal region of Ondo State, Nigeria is one of Technology, Akure, Nigeria, Tel: 234-806-644-7549; E-mail: [email protected]/ [email protected] 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 Received May 20, 2015; Accepted June 17, 2015; Published June 22, 2015 from tankers, offshore platforms, drilling rigs and well, as well as spills Citation: Olusola JO, Festus AA (2015) Levels of Heavy Metal in Some Selected of refined petroleum product (such as gasoline, diesel etc.) and their Fish Species Inhabiting Ondo State Coastal Waters, Nigeria. J Environ Anal Toxicol 5: 303. doi:10.4172/2161-0525.1000303 by-products and heavy fuel used by large ship. Oil spillage into water affects the ecosystem and its component negatively. Among animal Copyright: © 2015 Olusola JO, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits species, fish are the inhabitant that cannot escape from the detrimental unrestricted use, distribution, and reproduction in any medium, provided the effects of these pollutants. Fish are widely used to evaluate the health original author and source are credited. J Environ Anal Toxicol ISSN: 2161-0525 JEAT, an open access journal Volume 5 • Issue 5 • 1000303 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 Page 2 of 8 off the coast. They mainly abundant in warmer waters in both sides The main objectives of the present work is to determine the of the Atlantic Ocean, throughout the Mediterranean Sea, and in concentration of dissolved heavy metals (Pd, Cd, Cr, Zn, Cu, and Ni) in the Indian and the Western Pacific Oceans [7]. Most of this fish species water column of Ondo State coastal waters, estimate the accumulation feed in a variety of ways, ranging from sieving phytoplankton or grazing of these heavy metals in the muscle, eyes, gills, head, and bones of algae, to suction feeding on benthic invertebrates and to devouring other some commercially important fish species from the coastal waters; fishes whole or in portions [8]. and compare the levels of toxic metals in the examined fish species and water column with maximum allowable limits (MAL). The examined fish species have been used as bio-indicators to monitor heavy metals concentrations in the coastal environment, Materials and Methods due to their wide range of distribution, feeding rate, their important position in the food chain, and also because they produce evidence of Study area relatively stable concentration. The major occupation of the inhabitants The study was carried out in Ilaje Local Government Area (ILGA) in the coastal region is fishing, the water body and the examined fish (Figure 1) in the coastal area of Ondo State, Nigeria in January 2014. species remains the sole source of livelihood for the inhabitants. As ILGA is at the extreme Southern part of Ondo state. ILGA shares such, having understood that oil explorations and other industrial boundaries with Okitipupa Local Government Area in the North; activities could result into heavy metal pollution of the aquatic system, the Atlantic Ocean in the South; Ijebu Waterside Local Government it becomes imperative to continuously monitor the effect of this activity Area (Ogun State) in the West and Delta state in the East. Ilaje local on the ecosystem. Recent studies have shown that because of high rates government area is considered as one of the most important fishing of pollution in aquatic environments especially in developed world areas in the coast which have rich biodiversity that contains a diverse as a result of increased urbanization and industrialization activities, assemblage of fish, shellfish (shrimps, crabs, lobster, gastropods fishes and fishery products contain traces of heavy metals which can be and cephalopoda), reptiles and other living organisms [10]. ILGA detrimental to the health of consuming public [9].