Evaluations of the Levels of Heavy Metals in River Water and Selected Species of Fish from Ogba River in Benin City, Nigeria

Idowu Izegaegbe Joshua,Eshoe Gift Iyi-Aguebor

doi:10.4314/jasem.v21i6.16

Abstract

Ogba River provides source of drinking water in Benin City metropolis and also serves as repository for urban drainage and agrochemical wastes which could potentially impact the water and biota such as fish. This study was therefore aimed at assessing the concentrations of copper, cadmium, chromium and lead in water and fish from Ogba River (Nigeria). The dominant fish species encountered in the study are Clarias gariepinus, Hemichromis fasciatus and Tilapia mariae with mean weight of 127.86g, 116.60 and 74.46g respectively. Water and whole fish tissues were acid digested and analyzed for metal concentrations using the atomic absorption spectrophotometer. The results showed that in water and fish species, copper concentrations of 0.211 mg/l and 0.760 mg/kg were highest in station one, while chromium concentrations of 0.002 mg/l and 0.040 mg/kg were lowest in station two. There was significant difference in the mean concentration of the heavy metals in the selected fish species (P<0.05). The need for enforcement of regulations inhibiting unwise use of aquatic resources and regular monitoring of environmental matrices (water, sediment, and fauna) is advocated given that fish from Ogba River is unfit for human consumption. Key words: Heavy metals, Ogba River, fish.

Highlights

Heavy metals are found as natural components in aquatic ecosystems and anthropogenic influences can result to enrichment
Fish has been widely used as a suitable bio-indicator of metal contamination due to their relative ease of accumulation and the potential to biomagnify in man via consumption (Izegaegbe and Oloye, 2017, Wanboje and Oronsanye, 2013) Studies have demonstrated that fish on exposure to high amounts of heavy metals can accumulate reasonable quantities into tissues (Wangboje and Oronsaye, 2001)
The human health risk arising from the consumption of fish contaminated heavy metals is a growing concern in Nigeria, a region which is heavily populated and where large populaces depend on fish for protein sources

Summary

Introduction

Heavy metals are found as natural components in aquatic ecosystems and anthropogenic influences can result to enrichment. The human health risk arising from the consumption of fish contaminated heavy metals is a growing concern in Nigeria, a region which is heavily populated and where large populaces depend on fish for protein sources. This invariably underscores the importance of possible health hazard associated with heavy metal tainted fish. Studies on Ogba River have been reported (Obasohan and Oronsaye, 2004, Wangboje and Oronsanye, 2001, Obasohan et al; 2006, Obasohan, 2007) to be contaminated with heavy metals in the environmental matrices (water, sediment and fish fauna). The objective of this paper is to investigate the levels of some heavy metals in river water and selected fish species in Ogba River in Benin City, Nigeria

Objectives

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Results