The aim of this research is to determine the level of heavy metals contamination of agricultural soil and to reduce its concentration in the soil. Soil sampled at Inua Eyet Ikot, Mkpanak, Ibeno Local Government Area of Akwa Ibom State was analyzed to check for the initial heavy metal concentration of the soil. Poultry litter as a nutrient additive bearing microorganisms, bacteria and fungi was introduced to the soil to reduce the concentration of heavy metals. The sampled soil was mixed with poultry litter at three different proportions i.e. poultry litter to crude oil contaminated soil namely PL 20% + COCS, PL 40% + COCS and PL 50% + COCS. Heavy metals Copper(Cu), Iron (Fe), Manganese (Mn), Lead (Pb), Cadmium (Cd), Arsenic (As), Chromium (Cr), Nickel (Ni) concentration in the soil before and after 8 weeks were measured and analyzed by Atomic Absorption Spectrophotometer (AAS) analysis which was carried out using wet oxidation method (digestion) for soils. The treatment category PL 50% + COCS proved to be more effective in the reduction of heavy metals in the soil as it reduced Copper, Iron, Manganese, Lead, Cadmium, Arsenic, Chromium and Nickel by 87.5%, 92.2%, 93.37%, 49.72%, 67%, 66.8%, 76.1% and 73.7%. Reductions in all treatment categories were statistically analyzed by Analysis of Variance (ANOVA) and was found to be significantly different from the untreated soil at probability value P<0.05, with the significance level at 95%. The research findings indicate that poultry litter, which has microorganisms in it, enhances reduction of the concentration of heavy metals in contaminated soils.
Keywords: heavy metals, poultry litter, bioremediation, crude oil contaminated soil
ABSTRACT viii
CHAPTER ONE
1.0 INTRODUCTION 1
1.1 Background of Study 1
1.2 Statement of Problem 2
1.3 Aims and Objectives of Study 3
1.4 Significance of Study 3
1.5 Scope of Study 4
1.6 Limitation of Study 4
CHAPTER TWO
2.0 LITERATURE REVIEW 5
2.1 The Properties of Refine Gas Oil and Crude oil 5
2.2 Physical and Chemical Properties of Hydrocarbon and their Biodegradation. 6
2.3 Effects of Crude Oil On Soil Physical Properties 6
2.4 Effects of Petroleum and Oil – Based Products on Soil 7
2.5 Heavy Metals in Contaminated Soils and its Effects 8
2.6 Methods of Cleaning up Petroleum – Contaminated Soils 9
2.6.1 Ex-situ approach 9
2.6.1.1 Excavation 9
2.6.1.2 Soil washing 10
2.6.2 In – situ Approach 10
2.6.2.1 Bioremediation 11
2.6.2.2 Phytoremediation 11
2.7 Micro – Organisms in Bioremediation 11
CHAPTER THREE
3.0 Materials and Methods 13
3.1 Description of the Study Area 13
3.1.1 Study area location map 14
3.1.2 Field Sampling 15
3.2 Experimental Design 18
3.3 Particle Size Distribution and Bulk Density 18
3.3.1 Apparatus 18
3.3.2 Media 18
3.3.3 Reagents 18
3.3.4 Equipment 18
3.4 Soil Moisture Content and Hydraulic Conductivity 20
3.4.1 Apparatus 20
3.4.2 Equipment 20
3.5 Microbiological Analysis 21
3.5.1 Serial dilution of samples 21
3.5.1.1 Apparatus 21
3.5.2 Estimation of Microbial Load from the samples 21
3.5.2.2 Media 22
3.5.3 Incubation of culture plates and counting of microbial colonies 23
3.5.3.2 Equipment 23
3.5.4 Purification and maintenance of microbial isolates 23
3.5.4.1 Apparatus 23
3.5.4.2 Media 23
3.5.5 Characterization and Identification of microbial isolates 23
3.5.5.1 Equipment 23
3.5.6 pH Analysis 25
3.5.6.1 Apparatus 25
3.5.6.2 Equipment 25
3.5.7 Heavy Metals Analysis 26
3.5.7.1 Apparatus/Materials 26
3.5.7.2 Equipment 26
3.5.7.3 Reagents 26
3.6 Statistical Analysis 27
CHAPTER FOUR
4.0 RESULTS AND DISCUSSION 28
4.1 Particle Size Distribution and Bulk Density 28
4.2 Soil Moisture Content 30
4.3 Total Microbial Count 32
4.4 Microbial Isolates 35
4.5 pH Analysis 36
4.6 Heavy Metals Analysis Results 38
4.7 Heavy Metal Analysis Discussion 44
4.7.1 Copper (Cu) 44
4.7.2 Iron (Fe) 45
4.7.3 Manganese (Mn) 45
4.7.4 Lead (Pb) 45
4.7.5 Cadmium (Cd) 46
4.7.6 Arsenic (As) 46
4.7.7 Chromium (Cr) 47
4.7.8 Nickel (Ni) 47
CHAPTER FIVE
5.0 CONCLUSION AND RECOMMENDATIONS 48
5.1 Conclusion 48
5.2 Recommendation 48
LIST OF FIGURES Page
Figure 3.1a Akwa Ibom State showing the Study Area 14
Figure 3.1b Crude oil contaminated site showing Study Area and 15 Sample Location
Figure 4.1 Soil Particle Size Distribution (0 – 15cm) at 8 weeks 29 after treatments
Figure 4.2 Relative proportions of sand, silt and clay in the treatments 30 categories
Figure 4.3 Percentage moisture content of the treatment categories 32
Figure 4.4 THBC, FC and TCC counts 34
Figure 4.5 CC, HUB and HUF counts 45
Figure 4.6 pH levels of treatments and soil before and after 8 weeks 38
Figure 4.7 Initial and final concentration of Heavy metals in untreated soil 42
before and after 8 weeks
Figure 4.8 Initial and final concentration of Heavy metals in 43
PL 20% + COCS before and after 8 weeks.
Figure 4.9 Initial and final concentration of Heavy metals in 44
PL 40% + COCS before and after 8 weeks.
Figure 4d Initial and final concentration of the Heavy metals in 45
PL 50% + COCS before and after 8 weeks.
LIST OF TABLES
Page
Table 2.1 Microbial Genera Degrading Hydrocarbon in Soils 12
Table 4.1 Particle size distribution of the treatment categories 28
Table 4.2 Some characteristics of the top 0 – 15 cm soil of the 29 experimental site and poultry litter.
Table 4.3 Relative Proportions of sand, silt and clay in the treatments 30
Table 4.4 Percentage Moisture Content of Experimental groups 31
Table 4.5 THBC, FC and TCC Counts 33
Table 4.6 CC, HUB and HUF Counts 34
Table 4.7 Microbial Isolates of the Samples. 36
Table 4.8 Occurrence and Distribution of the Diverse Microbial Isolates 37
Table 4.9 Initial Concentration levels of Heavy metals 39
Table 11 Final Concentration levels of Heavy metals 39
Table 12 ANOVA at Week 0 40
Table 13 ANOVA at Week 8 41
LIST OF PLATES
Page
Plate3.1 Picture of soil sample collected in a plastic container 16
Plate 3.2 Picture of the poultry litter in a plastic container 16
Plate 3.3 Picture of device used as GPS device 17
Plate 3.4 Serial Dilution of Samples 22
Plate 3.5 Bacteria Isolates 24
Plate 3.6 Fungi Isolates 24
Plate 3.7 pH Analysis 25
Plate 3.8 Atomic Absorption Spectrophotometer 27
