Assessment Of Heavy Metal Pollution in Water, Soil and Rice Grown Around River Yobe, Nigeria

ABSTRACT The study was carried out to determine the levels of pollution, by selected metals. in water, soil and rice grown around River Yobe, Nigeria. The samples were collected from four different locations and were analyzed for physicochernical parameters, heavy metals and pollution indices. The pH of water and soil samples were found to be within the range of 6.47 ± 0.05 — 6.85 ± 0.13 and 6.00 — 7.70 respectively. The EC, Alkalinity, chloride, hardness, TDS and turbidity of the water samples were in the ranges of 2.12 ± 0.27—2.67 ± 0.35 ds/m; 67.23 + 0.43 —92.33 ± 0.58 mg/L; 0.73 ± 0.02—0.89 ± 0.08 mg/L; 26.67 + 2.31 — 35.67 ± 0.58 mg/L 1357 ± 1.08— 1708 + 1.99 mg/L and 2.23 ± 0.77— 164.20 ± 0.32 FTTJ respectively. The nutrient concentrations in this study showed that the soils samples had low (< 100 kg! Acre) levels of’ nitrogen. Also phosphorous levels in sites P1 and P3 were found to be low in concentrations while medium (100-200 kg! Acre) levels were registered in sites P2 and P4. High (> 200 kg/Acre) level of potassium level was recorded in the sampling sites. MC and AC of plants were within the recommended ranges. The study found out that in water samples Ci’, Fe and Pb had higher values than the permissible limit set by NSDWQ. In the soil samples, the concentrations of Cr, Cu, Fe and Pb were found to be above the WHO permissible limits. In rice grain samples Cu and Zn concentrations were also above the WHO standard limits. In rice leave samples the concentrations Cr and Zn were found to be within the acceptable limits. The contamination factor and geoaccumulation index in all the sampling sites indicated low to moderately contamination levels while the transfer of Pb from soil to plants was found to be in high levels. The findings of this research work proved that the samples collected were polluted by the metals under study.

TABLE OF CONTENTS

DECLARATION

APPROVAL

.

Ii

DEDICATION

ACKNOWLEDGMENTS iv

LIST OF FIGURES V

LISTOF TABLES vi

ABBREVIATIONS ii

TABLE OF CONTENTS iii

ABSTRACT

CHAPTER ONE

INTRODUCTION I

1 .0 Background of the Study

.1 Problem Statement 3

1.2 Objectives 3

1.2.1 General objective 3

1.2.2 Specific objectives 3

1 .3 Research Questions 4

1 .4 Research Hypothesis 4

1.5 Scope of the Study 4

1.5.1 Geographical scope 4

1.5.2 Time scope 5

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1.5.3 Content scope

1 .6 Justification

1 .7 Significance ofthe Study 5

1.8 Definition of terms 6

CHAPTER TWO 7

LITERATURE REVIEW 7

2.0 Introduction 7

2.2 Heavy Metal Pollution 7

2.3 Metal Pollution in a River 9

2.3 Effects of Durnpsites in the Environment I 0

2.4 Heavy Metals in Soils 13

2.5 Heavy Metal in Food Crops 14

2.6 Pollution Indices Used for Soil Analysis 1 6

2.7 Transfer Factors (TF) 1 6

2.8 Geo-accurnulation Index (GEOI) 1 7

2.9 Contamination Factor (CF) 1 8

CHAPTER THREE 20

MATERIALS AND METHODS 20

3.0 Study Area 20

3.1 Research Design 21

3.2 Sample Collection 21

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3.2.1 Water sampling .21

3.2.2 Plant sampling 21

3.2.3 Soil sampling 22

3.3 Samples Preparation 22

3.3.1 Plant 22

3.3.2 Soil 22

3.4. Analysis of Water Samples 23

3.4.1 pH of water 23

3.4.2 Conductivity of water 23

3.4.3 Total hardness of water 23

3.4.4 Determination of heavy metal concentrations 23

3.5 Analysis of Plant Samples 24

3.5.1 Determination of moisture content of plant samples 24

3.5.2 Determination of ash content of plant samples 24

3.5.3 Digestion of plant samples (leave) 24

3.5.4 Digestion of plant samples (grain) 25

3.5.5 Determination of heavy metal concentration 25

3.6 Analysis of Soil Samples 26

3.6.1 Determination of soil pH 26

3.6.2 Estimation of available nitrogen in soil 26

3.6.3 Estimation of available phosphorus in soil 26

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3.6.4 Estimation of available potassium in soil .27

3.6.5 Digestion of soil samples 28

3.7 Quality Control 29

3.8 Data Analysis 29

3.9 Determination of Pollution Indices of Soil around the Dumpsites 30

3.91 Contamination factor 30

3.9.2 Geo-accurnulation index 30

3.9.3 Transfer factor 30

CHAPTER FOUR 32

RESULTS AND DISCUSSION 32

4.1 Physicochernical Properties of Samples 32

4.1.1 Results of physicochemical parameters of water samples 32

4.1.2 Proximate compositions of plant samples 35

4.1.3 Nutrient in soil samples 36

4.2 Evaluation of Heavy Metal Concentrations 37

4.2.1 Heavy metal concentrations in river water 37

4.2.2 Heavy metal concentrations in soil samples 41

4.2.3 Heavy metal concentrations in rice grain samples 44

4.2.4 Heavy metal concentrations in rice leaf samples 48

4.3 Data Analysis 51

4.3.1 Analyses of variance SI

4.3.2 Correlation .52

4.4 Pollution Indices 53

4.4.1 Transfer factor from soil to grain and soil to leaves samples 55

4.4.2 Contamination factor (CF) 55

4.4.3 Ceo-accumulation indices 57

CHAPTER FIVE 58

CONCLUSIONS AND RECOMMENDATIONS 58

5.1 Conclusions 58

5.2 Recommendations 60

5.3 Further Research 60

REFERENCES 61

APPENDICES 71