ABSTRACT
This study was done to evaluate the risk of heavy metals pollution of soils within the vicinities of refuse dumpsites in Calabar south, LGA. Soil samples were collected from a depth of 0-20cm with the use of a soil auger from ten (10) dumpsites using the stratified sampling method. The samples were well labelled in polythene bags and transported to the laboratory where it was air-dried and subjected to physico-chemical analysis. Heavy metals such as lead (Pb), cadmium (Cd), chromium (Cr), mercury (Hg) and nickel (Ni) were analytically determined by using the atomic absorption spectrophotometer and a statistical analysis was carried out with the use of SPSS and Microsoft excel 2007. The mean concentration of nickel (Ni) ranged between 0.93-1.64, the mean concentration of chromium (Cr) ranged between 0.18-0.36, the mean concentration of cadmium (Cd) ranged between 0.05-0.52, the mean concentration of lead (Pb) ranged between 0.01-0.03 and the mean concentration of mercury remained constant at ( Cr > Cd > Pb > Hg. The dumpsites encourage the accumulation of heavy metal in soils because of the various components of refuse generated in the society. Based on the study, the following recommendations are made; containers/waste bins should be kept at different sites/areas for dumping of wastes of different categories instead of dumping the waste on the soil which later causes pollution, soil & groundwater monitoring programs should be initiated, establish guidelines for reclamation of areas contaminated by heavy metals, liming should be carried out on affected soils.
TABLE OF CONTENTS
TITLE PAGE i
CERTIFICATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT v
TABLE OF CONTENTS
CHAPTER ONE: INTRODUCTION
1.1 Justification of the Study 1
1.2 Aim and Objectives of the Study 2
CHAPTER TWO: LITERATURE REVIEW
2.1 Sources/Classification of Heavy Metals 3
2.1.1 Sources of Lead 3
2.1.2 Sources of Mercury 5
2.1.3 Sources of Cadmium 7
2.1.4 Sources of Chromium 9
2.1.8 Sources of Nickel 12
2.2 Disposal Systems for Municipal Solid Waste (MSW) 15
2.3 Waste Management Strategies Used In Municipal Solid Waste (MSW) 16
2.3.1 Open Disposal/Open Dumps 18
2.3.2 Landfills/Sanitary Landfills 19
2.3.3 Ocean Disposal 20
2.3.4 Incineration Plants 20
2.4 Accumulation/Contamination of Heavy Metals in the Environment 21
2.5 Effects of Heavy Metals Contamination 23
2.5.1 Lead Effects 24
2.5.2 Mercury Effects 26
2.5.3 Cadmium Effects 27
2.5.4 Chromium Effects 29
2.5.8 Nickel Effects 30
2.6 Preventing Contamination by Heavy Metals/Remediation 31
2.6.1 Immobilization Techniques 34
2.6.2 Soil Washing 35
2.6.3 Phytoremediation 37
CHAPTER THREE: MATERIALS AND METHODS
3.1 Location/Study Sites 39
3.2 Materials 40
3.3 Method of Sampling 40
3.4 Sample Preparations 40
3.5 Chemical Analysis 41
3.6 Statistical Analysis 41
CHAPTER FOUR: RESULTS AND DISCUSSION
4.1 Results 42
4.2 Discussion 43
4.2.1 Lead (Pb) 44
4.2.2 Cadmium (Cd) 44
4.2.3 Chromium (Cr) 45
4.2.4 Nickel (Ni) 45
4.2.5 Mercury (Hg) 46
CHAPTER FIVE: CONCLUSION AND RECOMMENDATION
5.1 Conclusion 47
5.2 Recommendation 47
REFERENCES
APPENDIX
