DETERMINATION OF THE LEVELS OF POLYCYCLIC AROMATIC HYDROCARBONS PAHs AND HEAVY METALS IN SOILS AND PLANT FOOD CULTIVARS FROM SOME OIL EXPLORATION COMMUNITIES OF BAYELSA STATE
ABSTRACT
Soils and vegetation in three selected communities in Bayelsa state were investigated for presence of recalcitrant Polycyclic aromatic hydrocarbons PAHs and heavy metals in the soils and edible plant food cultivars Two of the communities, Angiama and Oporoma are crude oil impacted areas having had oil spillage accidents in 2010 and 2008 respectively while Yenagoa a non crude oil impacted area is used as control Physicochemical properties of soils from these study areas were investigated using standard methods, the polycyclic aromatic hydrocarbon PAHs in the soil and food cultivars were determined using Gas Chromatography Mass Spectrophotometer while heavy metals were analysed by Atomic Absorption Spectrophotometer The result of the investigation reveal that oil spillage degrades the soil as revealed by the significant reduction in pH , moisture content and bulk density of soils from Angiama and Oporoma communities compared with Yenagoa Soil from Angiama had the highest percentage organic carbon 440053 and total hydrocarbon 846401011mg/kg followed by Oporoma 213012 and 52000500mg/kg respectively and Yenagoa 130108 and 6220026mg/kg respectively The anion levels of soil nitrate NO3 2 and phosphate PO4 3 were significantly highest in soil residues from Yenagoa than in Angiama and Oporoma while the levels of exchangeable cations Ca2, Mg2, K,and Na were highest in Angiama than in Oporoma and Yenagoa soils The values were significantly different at plt;005This suggest that exchangeable cations accompany oil spill High molecular weight recalcitrant PAHs Benzoa pyrene, benzoa anthracene, BenzoK fluoranthene, Benzobfluoranthene were present in both Angiama and Oporoma soil but were not detected in Yenagoa Except for phenanthrene, low molecular weight PAHs were not detected in soil samples from Yenagoa, occurred sparingly in Oporoma but were predominant in Angiama Food cultivars from both Angiama and Oporoma were equally proportionately contaminated with these high molecular weight PAHs The leafy vegetables pumpkin and scent leaf were far more contaminated than the tubers yam and cassava Heavy metal contaminants of soils and food cultivars mirror exactly the same trend associated with recalcitrant PAHs These results reveal that oil spillage activity is responsible for the preponderance of PAHs and heavy metals in the soils of the Niger Delta It also demonstrates that by the process of natural weathering polluted soils are remedied over time Given the appreciable accumulation of these crude fraction toxicants in food cultivars, it is suggested that the foods remain a major endogenous source of PAHs and heavy metals among the people of the area
TABLE OF CONTENTS
Title page ii
Certification iii
Approval iv
Dedication v
Acknowledgement vi
Abstract vii
Table of content viii
List of tables ix
List of figures x
List of Abbreviations xi
Chapter One
10 Introduction 1
11 Statement of the problem 2
12 Aims and objectives 3
13 Significant of the study 3
14 Relevance of the study 4
15 Description of the study areas with maps and pollution history 4
Chapter Two
20 Literature review 8
21 Occurrence of Polycyclic aromatic hydrocarbons PAHs 8
22 List of Polycyclic aromatic hydrocarbons PAHs 9
23 Classification of PAHs 10
24 Transport and Partitioning of PAHs 11
241 Vapour pressure 11
242 Henrys Law 12
243 Solubility 12
244 Octanol water Kow and Organic Carbon Koc Partition Coefficient 13
25 Health hazards oh PAHs 14
251 Respiratory effect 14
252 Immunological effects 14
253 Reproductive effects 15
254 Developmental effects 15
255 Genotoxic effects 16
256 Cancinogenic effect 18
26 Pollution sources of PAHs 19
261 Air 20
262 Water 20
263 Soil 21
27 Heavy metal contaminants of crude oil 21
271 Lead Pb 22
272 Cadmium Cd 24
273 Copper 26
274 Zinc Zn 28
275 Iron fe 30
276 Nickel Ni 31
28 Crude oil spills and the environment 32
29 Recalcitrant PAHs 34
210 Uptake of PAHs and Heavy metals by food crops 35
Chapter Three
30 Materials and Methods 38
31 Materials 38
311 Equipments/Apparatus 38
312 Chemicals and Reagents 38
32 Methods 39
321 Sample collections and preparation 39
3211 Sample collection 39
3212 Sample preparation 40
322 Analytical methods 41
3221 Characterization of soil samples 41
3222 Physicochemical analysis of soil samples 41
3223 Determination of PAHs 45
3224 Determination of heavy metal contaminant 47
3225 Result Analysis 48
Chapter Four
40 Results 49
41 Physicochemical properties of soils from polluted areas 49
42 Residual polycyclic aromatic hydrocarbon constituents of soils from the study areas 51
43 Polycyclic aromatic hydrocarbon levels in tuber cultivars from the study areas 53
44 Polycyclic aromatic hydrocarbon levels in plant leaves from the study areas 56
45 The composite pattern of PAHs distribution in soils and plant food cultivars in Yenagoa 59
46 The composite pattern of PAHs distribution in soils and plant food cultivars in Angiama 60
47 The composite pattern of PAHs distribution in soil and plant food cultivars from Oporoma 62
48 Heavy Metal Constituents of soils from the study areas 64
49 Heavy Metal Constituents in tuber cultivars from the study areas 65
410 Heavy Metal Constituents in plant leaves from the study areas 68
411 Composite pattern of heavy metal distribution in soils and food cultivars in Yenagoa 71
412 Composite pattern of heavy metal distribution in soils and food cultivars in Angiama 72
413 Composite pattern of heavy metal distribution in soils and food cultivars in Oporoma 74
Chapter five
50 Discussion 66
51 Physicochemical properties of soil from the study areas 66
52 Residual Polycyclic aromatic hydrocarbon constituents of soils from the study areas 67
521 Polycyclic Aromatic hydrocarbon levels in tuber cultivars from the study areas 69
523 Polycyclic Aromatic hydrocarbon levels in plant leave from the study areas 70
53 Heavy metal concentration in soil from the study areas 72
531 Concentrations of Heavy metal in tuber cultivars from the study areas 73
532 Heavy metal concentration in plant leaves from the study areas 73
Conclusion 78
Contribution to knowledge 78
References 79
Appendices 88
: INTRODUCTION1.1 Background to the Study 11.2 Statement of the Problem 101.3 Purpose of the Study 131.4 Scope o...
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