ABSTRACT

The microbiological and physicochemical characteristics of soil contaminated with petroleum products were carried out. A total of 3 sampling sites ( Filling station, mechanic workshop and areas around power generating plant) were investigated. The media used were Nutrient agar, Sabouraud dextrose agar, Mineral salt agar for Isolation of total heterotrophic bacteria and fungi and hydrocarbon-utilizing bacteria and fungi, respectively. The pour plate method is used for the isolation of microorganisms. The total heterotrophic bacterial count ranged from 1.4×107±0.36 - 1.7×108±0.06 cfu/g, while the total heterotrophic fungal count ranged from 6.0×105±0.63 - 9.0×106±4.0 cfu/g. The hydrocarbon-utilizing bacterial count ranged from 3.0×105±0.81 - 2.3×106±0.17 cfu/g, while hydrocarbon-utilizing fungal count ranged from 1.0×106±0.2 - 1.4×106±0.2 cfu/g. The microorganisms isolated were Bacillus species, Escherichia coli, Staphylococcus species, Klebsiella species, Micrococcus species, Penicillium species, Aspergillus species, Rhizopus species and Mucor species. The result of the physicochemical parameters ranged as follows: Oil and grease, 520mg/kg to 615mg/kg; total organic carbon, 22.10% to25.65%; pH, 3.8 to 4.3; Conductivity, 129µS/cm to 134µS/cm; Phosphate, 1.92 mg/kg to 2.26 mg/kg; Sulphate, 12.70mg/kg to 16.30mg/kg; Nitrate, 1.72mg/kg to 2.19mg/kg; Total Iron, 39.5mg/kg to 53.4mg/kg; Copper, 1.92mg/kg to 2.26mg/kg; Nickel, 0.081mg/kg to 0.102mg/kg; Cadmium, 0.049mg/kg to 0.085mg/kg, Barium, 0.034mg/kg to 0.046mg/kg; Manganese, 7.08mg/kg to 9.47mg/kg; Sodium, 13.7mg/kg to 18.4mg/kg; Magnesium, 1.86mg/kg to 3.72mg/kg; Potassium, 4.11mg/kg to 5.21mg/kg; and Calcium, 129mg/kg to 169mg/kg. It has been observed that the used petroleum had impacted negatively on the soil within the vicinity of the polluted sites and could affect vegetation around the area.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

List of Tables x

Abstract ix

CHAPTER ONE: INTRODUCTION 1

1.1  Aims and objectives 3

CHAPTER TWO: LITERATURE REVIEW 4

2.1  The Biology of Soil 4

2.2  Petroleum and its Derivatives 5

2.3  Environmental contamination of soil 6

2.4  Sources of Petroleum contamination in soil 6

2.5  Effect of petroleum contamination 6

2.6  Effect of soil contamination on ecosystem 7

2.7  Clean up of soil 7

2.7.1 Bioremediation of sites contaminated by petroleum derivatives 10

2.8  The physical characteristics of soil 11

1.8.1 Soil texture 11

1.8.2 Soil structure 12

1.8.3 Soil tilth 13

1.8.4 Soil water 13

1.8.5 Soil organic matter 14

1.9  Chemical properties of soil 14

1.9.1 Cat ion exchange 14

1.9.2 Soil pH 15

1.9.3 Soil salinity 16

1.9.4 Heavy metals 16

CHAPTER THREE: MATERIALS AND METHODS 19

3.1 Study area 19

3.2 sample collection 19

3.3 Microbiological methods 19

3.3.1 Media 19

3.4  Enumeration of Total Heterotrophic Bacteria and Fungi 20

3.5  Enumeration of hydrocarbon-utilizing Bacteria and Fungi 20

3.6  Characterization and identification of Hydrocarbon utilizing isolates 21

3.6.1 Macroscopic Examination 22

3.6.2 Microscopic Examination 22

3.6.3 Gram staining 22

3.6.4 Lacto phenol cotton blue 22

3.6.5 Spore Staining 23

3.6.6 Motility Test 23

3.7  Biochemical Tests 24

3.7.1 Catalase test 24

3.7.2 Citrate test 24

3.7.3 Oxidase test 24

3.7.4 Indole test 24

3.7.5 Urease test 25

3.7.6 Coagulase test 25

3.7.7 Methyl red- Voges proskquer test 25

3.7.8 Triple Sugar Iron Agar (TSIA) Test 25

3.7.9 Starch Hydrolysis Test 26

3.7.10 Sugar Fermentation Test 26

3.8  Determination of physicochemical parameters 27

3.8.1 pH Determination 27

3.8.2 Electrical Conductivity 27

3.8.3 Determination of sulphates 27

3.8.4 Determination of nitrates 28

3.8.5 Determination of phosphates 28

3.8.6 Heavy metal Analysis 29

3.8.7 Determination of oil and grease and Total Petroleum Hydrocarbon(TPH) 29

3.8.8 Determination of Total Organic Carbon 29

3.8.9 Determination of Exchangeable Cat ions 30

CHAPTER FOUR: RESULTS 31

CHAPTER FIVE: DISCUSSION, CONCLUSION, RECOMENDATION 41

5.1  Discussion 41

5.2  Conclusion 44

5.3  Recommendation 44

References

Appendix