TABLE OF CONTENTS
Title Page
Certification
Acknowledgment
Abstract
Table of Content
List of Figures
List of Tables
List of Abbreviations
CHAPTER ONE: INTRODUCTION
1.1. Introduction
1.2. Physical and Chemical Characteristics of PAHs
1.3. Sources and Emission of PAHs
1.3.1. Stationary Sources
1.3.1.1. Domestic Sources
1.3.1.2. Industrial Sources
1.3.2. Mobile Sources
1.3.3. Agricultural Sources
1.3.4. Natural Sources
1.3.5 Uses of PAHs
1.4. Routes of Exposure for PAHs
1.4.1 Air
1.4.2 Water
1.4.3 Soil
1.4.4. Foodstuffs
1.4.5. Other Sources of Exposure
1.5. Individuals at Risk of Exposure
1.6. Standards and Regulation for PAH Exposure
1.7. Metabolism of PAHs
1.7.1. Fate of PAHs in Soil and Groundwater Environment
1.7.2. Fate of PAHs in Air and their Ecotoxicological consequences
1.8 Human Health Effects
1.8.1 Acute or Short-Term Health Effects
1.8.2. Chronic or Long-Term Health Effects
1.8.3 Carcinogenicity
1.8.4. Teratogenicity
1.8.5. Genotoxicity
1.8.6. Immunotoxicity
1.8.7. effect of PAHs Pathogenic Change
1.9. Fish
1.9.1. Food Smoking
1.10. Rationale of Study
1.11. Aims and Objectives
CHAPTER TWO: MATERIALS AND METHODS
2.0 Material and methods
2.1. Materials
2.1.1. Apparatus and Equipment
2.1.2. Chemicals
2.1.3. Fish Samples
2.1.4. Study Site
2.2. Methods
2.2.1. Collection of Fish Samples and Drying
2.2.2. Sample Preparation for the Analysis of Dried Fishes
2.2.3. Preparation of Florisil for clean-up
2.2.4. Instrument Analysis
CHAPTER THREE: RESULTS
Result
CHAPTER FOUR
4.0. Discussion
Conclusion
Reference
Appendices
ABSTRACT
Preservation of fish by drying over different types of heat regimes have been known. However, there has not been a comprehensive comparison in terms of the possible contamination associated with these drying regimes. This work was set to evaluate the levels of PAHs that are likely to accumulate in the bodies of fresh water fishes dried under heat from charcoal, sun (sun drying), electric oven and polythene augmented drying regimes (burning of used cellophone materials). The levels of sixteen PAHs were determined in fish samples harvested from Otuocha River in Anambra State, Nigeria. The fish samples were dried, pulverized and subjected to soxhlet extraction using n-hexane at 600c for 8hrs. The water content of the eluants were further removed with florisil clean-up before Gas chromatographic – mass spectrometric analysis. Results obtained showed that sun-dried fish had PAHs concentration to be 35.7+ 0.2µg/g; oven dried gave 47.7+ 0.2µg/g and charcoal dried 79.53+ 0.2µg/g, while drying with firewood resulted in 188.1+ 0.2µg/g. Charcoal drying augmented with polythene resulted into PAHs level of 166.2+ 0.1µg/g while fish dried under heat generated from burning firewood and polythene material resulted into PAHs concentration of 696.3+0.2µg/g. Preliminary analysis of the fresh water samples and the undried fish samples (control) revealed that the fresh water contained total PAHs level of 2.86+ 0.1µg/ml, while the fresh fish 4.97+ 0.2µg/g. The concentration of PAHs in all the dried fish under different drying agents were significantly higher than the control. The result is more worrisome in that even the fishes dried under the sun have PAHs significantly higher than that of the control (p
CHAPTER ONE
1.1 INTRODUCTION
Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds consisting of two or more fused benzene rings (linear, cluster or angular arrangement), or compounds made up of carbon and hydrogen atoms grouped into rings containing five or six carbon atoms. They are called “PAH derivatives” when an alkyl or other radical is introduced to the ring, and heterocyclic aromatic compounds (HACs) when one carbon atom in a ring is replaced by a nitrogen, oxygen or sulphur atoms. PAHs originate mainly from anthropogenic processes particularly from incomplete combustion of organic fuels. PAHs are distributed widely in the atmosphere. Natural processes, such as volcanic eruptions and forest fires, also contribute to an ambient existence of PAHs (Suchanova et al., 2008). PAHs can be present in both particulate and gaseous phases, depending on their volatility. Low molecular weight PAHs (LMW PAHs) that have two or three aromatic rings (molecular weight from 152 to 178g/mol) are emitted in the gaseous phase, while high molecular weight PAHs (HMW PAHs), molecular weight ranging from 228 to 278g/mol, with five or more rings, are emitted in the particulate phase, (ATSDR, 1995) . In the atmosphere, PAHs can undergo photo-degradation and react with other pollutants, such as sulfur dioxide, nitrogen oxides, and ozone. Due to widespread sources and persistent characteristics, PAHs disperse through atmospheric transport and exist almost everywhere. There are hundreds of PAH compounds in the environment but in practice PAH analysis is restricted to the determination of six (6) to sixteen (16) compounds. Human beings are exposed to PAH mixtures in gaseous or particulate phases in ambient air. Long term exposure to high concentration of PAHs is associated with adverse health problems. Since some......================================================================
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