DETERMINATION OF HEAVY METAL CONCENTRATIONS IN FISH AND WATER OF IKPOBA RIVER

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CHAPTER ONE

INTRODUCTION 

1.1 BACKGROUND TO THE STUDY    

Water pollution is any form of damage to the physical, chemical and biological characteristics of water which then affect the quality and suitability for any designated use or purpose1, 2. Hence, it is an issue of great importance to protect the water sources from faecal, agricultural and industrial contamination or pollution which is continually threatening terrestrial and aquatic ecosystem due to increasing exposure of untreated wastes and chemical agents that are capable of causing damage to the environment3-5. For example, it has been reported that storm water runoff from urban areas contains numerous pollutants like polycyclic aromatic hydrocarbons (PAHs), heavy metals (HMs), biocides and suspended solids which are toxic or harmful to the aquatic environment and also have potential negative ecological impacts on receiving waters6. The negative impacts include eutrophication, oxygen depletion and chronic toxic effect towards aquatic flora and Fauna. The contamination of the environment, particularly the aquatic ecosystems by harmful waste indicators such as heavy metals and polycyclic aromatic hydrocarbons is a serious problem in the society because the environment is a direct receptacle for waste products generated in the space within the environment7, 8.

Here, however, heavy metals and polycyclic aromatic hydrocarbons are of particular concern due to their prevalent toxicity to aquatic organisms and are persistent in the environment9, 10. The toxicity of the aquatic environment poses threat to man for the fact that safe and suitable potable water supply for drinking and other uses are lacking especially in the rural settlement in Nigeria which makes rural dwellers to depend on rivers, streams, natural ponds, Lakes, shallow hand dug wells and collection of rainfalls to meet their water needs as well as depending on aquatic animals which are capable of bio-accumulating pollutants like Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) as sources of food11-13.

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) have been reported to have very carcinogenic, mutagenic and teratogenic effect on aquatic animals and humans who consume them or have direct encounter with the pollutants, especially with occupational exposure8, 14-19, therefore it is consequential to take the environmental study of Heavy metals and polycyclic aromatic hydrocarbons very seriously to avert their possible effect and costly consequence of their contamination effects if not checked.

                                                                             
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