vii
TABLE OF CONTENT
CHAPTER
TITLE
PAGE
DECLARATION ........................................................................... ii
DEDICATION
........................................................... iii
ACKNOWLEDGEMENT............................................................. v
ABSTRACT
........................................... vi
ABSTRAK .................................................................................... vii
TABLE OF CONTENTS
..................................................... viii
LIST OF TABLES ....................................................................... xii
LIST OF FIGURES .................................................................... xiv
LIST OF GLOSSARY .............................................................. xviii
1
INTRODUCTION ......................................................................... 1
1.1 Background ..................................................................................... 1
1.2 Statement of the Problem .................................................................. 4
1.3 Objectives ......................................................................................... 5
1.4 Significance of the Study .................................................................. 5
1.5 Scope of the Study ............................................................................ 5
1.6 Outline of the Thesis ......................................................................... 6
viii
2
LITERATURE REVIEW ............................................................. 7
2.1 Introduction ....................................................................................... 7
2.2 Definition of Heavy Metals ............................................................... 8
2.3 Sources of Heavy Metals in the Environment .................................. 9
2.4 Pollution ......................................................................................... 13
2.5 Toxicity of Heavy Metals................................................................ 15
2.6 Impact of Heavy Metals on the Environment ................................. 16
2.6.1 Heavy Metals Impact On Water .......................................... 16
2.6.2 Heavy Metals Impact On Soil and Plant ............................ 17
2.7 Effect of Heavy Metals on Animal Health ...................................... 19
2.8 Effect of Heavy Metals on Human Health ...................................... 20
2.9 Sorghum and Alfalfa ...................................................................... 22
2.10 Sources and Status of Water in Oman ............................................ 23
2.11 Heavy Metals Analysis ................................................................... 24
2.11.1 Atomic Absorption Spectrometry.................................. .....24
2.11.2 Inductively Coupled Plasma Spectrometry ......................... 27
2.12 Monitoring of Heavy Metals ......................................................... 32
3
EXPERIMENTAL ....................................................................... 36
3.1 Chemicals and Reagents ................................................................. 36
3.2 Instruments and Apparatus ............................................................. 36
3.3 Sampling Area................................................................................. 37
3.4 Sample collection ............................................................................ 37
3.4.1 Collection of Water Samples .............................................. 44
3.4.2 Collection of Soil Samples .................................................. 44
3.4.3 Collection of Plant Samples ................................................. 44
3.5 Extraction Procedure for the Soil Sample ...................................... 44
ix
3.6 Digestion Procedure for the Plant Sample ..................................... 45
3.7 Preparation of Standards and QCs Solutions ................................. 45
3.8 Sample Analysis .............................................................................. 47
3.8.1 pH of Water and Soil Samples ........................................... 47
3.8.2 Electric Conductivity (EC) of Soil...................................... 48
3.8.3 Total Nitrogen (N) of Soil .................................................. 48
3.8.4 Heavy Metals of Water, Plant and Soil............................... 48
3.9 Data Analysis .................................................................................. 49
4
RESULTS AND DISCUSSION .................................................. 50
4.1 Sampling Sites
4.2 Soil Taxonomy
…..50
……………………………………………... 52
4.3 pH and Electrical Conductivity (EC) and Total Nitrogen Values .. 56
4.4 Concentration of Heavy Metals in Soil ........................................... 59
4.4.1 Variation of Heavy Metal Content in 20 Farms ................ 59
4.4.2 Overall Mean Concentration of Heavy Metal in Four ...........
Regions .............................................................................. 62
4.5 Concentration of Heavy Metals in Plant ......................................... 67
4.5.1 Variation of Heavy Metal Content in 20 Farms ................ 67
4.5.2 Overall Mean Concentration of Heavy Metal in Four ...........
Regions in Plant ................................................................. 71
4.5.3 AAS Analysis of Heavy Metals in Plant ............................ 74
4.6 pH and EC of in Well Water ......................................................... 75
4.7 Concentration of Heavy Metals in Well Water ............................... 77
4.7.1 Variation of Heavy Metal Content in 20 Farms .................. 77
4.7.2 Overall Mean Concentration of Heavy Metal in Four .............
Regions .............................................................................. 80
x
4.8
4.9
5
Correlation between Concentration of Nickel in Soil, Plant and
Water Samples
85
Proposed Maximum Permissible Level of Heavy Metals in
Omani Soil and Well Water
87
CONCLUSION AND FUTURE WORK .................................... 89
5.1 Conclusions ............................................................................. 89
5.2 Future Work
91
REFERENCES ...................................................................................... 92
Appendix A-M
100 - 112
xi
LIST OF TABLES
TABLE NO.
TITLE
PAGE
2.1
Water balance in million cubic metres per year
24
2.2
Comparison between ICP-OES, FAAS and GAAS.
32
2.3
Maximum permissible levels of selected heavy metals in water,
33
soil and plant samples.
3.1
Latitude and Longitude coordinates of twenty farms selected
for the determination of levels of heavy metals in water, soil
and plant.
3.2
Calibration Standards (STD) concentrations of element under
study for ICP-OES
3.3
53
The pH, EC and total N range in soil samples of four regions in
the Sultanate of Oman
4.3
47
Taxonomy of soil of the selected farms (n=20) sampled for the
determination of heavy metal contents in water, soil and plants.
4.2
46
Calibration Standards (STD) concentrations of Cd, Cu, Cr, Mn,
and Zn for AAS.
4.1
38
57
Comparison of mean heavy metal concentrations (µg/g)
between Batinah North, Batinah South, Dakhliah and Sharqiah
regions in the Sultanate of Oman.
4.4
The mean concentration of heavy metals of plant of four
66
72
xii
regions in the Sultanate of Oman
4.5
Concentrations of Cd, Cu, Mn, and Zn in plant samples using
AAS
4.6
74
The pH and EC values in water samples of four regions in the
Sultanate of Oman
4.7
Classification of saline waters
4.8
Comparison of mean heavy metal concentrations in water
76
76
between Batinah North, Batinah South, Dakhiliyah and
Sharqiyah regions in the Sultanate of Oman
4.9
84
Proposed maximum permissible level of heavy metals in saoil
and water in the Sultanate of Oman
88
xiii
LIST OF FIGURES
FIGURE NO.
2.1
TITLE
PAGE
The relationship between health effect and the amount of
elements, for (a) Essential elements, and (b) toxic elements
2.2
16
The soil-plant system showing the key components relating to
the dynamics of heavy metals
18
2.3
Photographs of a) Sorghum and b) Alfalfa
22
2.4
Schematic diagram of (a) Graphite furnace and (b) Flame
burner
25
2.5
Schematic diagram of A hollow cathode lamp
26
2.6
Schematic diagram of flame atomic absorption spectrometry
27
2.7
Schematic diagram of Inductively Coupled Plasma- Optical
Emission spectrometry (ICP-OES)
28
2.8
Schematic diagram of Nebulizer
29
2.9
Schematic diagram of a typical ICP source called torch.
Position A shows radial viewing of the torch.
30
2.10
Temperature in typical ICP source
31
3.1
Map showing the locations of the four selected regions of
Oman sampled for measuring the heavy metal contents of 39
xiv
water, soil and plants.
3.2
Map showing the locations of 5 selected farms selected from
Batinah North (BN) region of Oman sampled for measuring the
heavy metal contents of water, soil and plants.
3.3
40
Map showing the locations of 5 selected farms selected from
Batinah South (BS) region of Oman sampled for measuring the
heavy metal contents of water, soil and plants.
3.4
41
Map showing the locations of 5 selected farms selected from
Dakhiliyah (DH) region of Oman sampled for measuring the
heavy metal contents of water, soil and plants.
3.5
42
Map showing the locations of 5 selected farms selected from
Sharqiah (SH) region of Oman sampled for measuring the
heavy metal contents of water, soil and plants.
4.1
Map of Oman showing the sampling regions. Inset showing
economic activity of the related sampling regions
4.2
43
51
Satellite map showing the locations of 5 selected farms each
from Batinah North & South regions of Oman sampled for
measuring the heavy metal contents of soil.
4.3
54
Satellite map showing the locations of 5 selected farms each
from Sharqiyah & Dakhiliyah regions of Oman sampled for
measuring the heavy metal contents of soil
4.4
55
The concentration of heavy metals in soil (µg/g) of Batinah
North and South regions in The Sultanate of Oman during
November, 2009 to July, 2010.
4.5
60
The concentration of heavy metals in soil (µg/g) of Dakhiliyah
& Sharqiyah regions in The Sultanate of Oman during
November, 2009 to July, 2010.
4.6
61
The overall mean level of heavy metals in soil (µg/g) of four
regions in The Sultanate of Oman during November, 2009 to 63
xv
July, 2010.
4.7
The concentration of heavy metals in soil (µg/g) of four regions
in The Sultanate of Oman during November, 2009 to July, 2010 64
4.8
The concentration of Cd, Co, Cu and Cr in soil (µg/g) of 20
farms in The Sultanate of Oman during November, 2009 to
July, 2010.
4.9
68
The concentration of Fe, Pb, Mn and Mo in plant (µg/g) of 20
farms in The Sultanate of Oman during November, 2009 to
July, 2010
4.10
69
The concentration of Ni, V and Zn in plant (µg/g) of 20 farms
in The Sultanate of Oman during November, 2009 to July,
2010.
4.11
70
The overall mean level of heavy metals in plant (µg/g) of four
regions in The Sultanate of Oman during November, 2009 to
July, 2010.
4.12
73
The concentration of heavy metals in plant (µg/g) of four
regions in The Sultanate of Oman during November, 2009 to
July, 2010.
4.13
73
The concentration of heavy metals in water (mg/L) of (a)
Batinah North and (b) Batinah South regions in The Sultanate
of Oman during November, 2009 to July, 2010.
4.14
78
The concentration of heavy metals in water (mg/L) of (a)
Dakhiliyah and (b) Sharqiyah regions in The Sultanate of
Oman during November, 2009 to July, 2010.
4.15
The overall mean level of heavy metals in water (mg/L) of four
79
81
xvi
regions in The Sultanate of Oman during November, 2009 to
June, 2011.
4.16
The concentration of heavy metals in water (mg/L) of four
sampling in The Sultanate of Oman during November, 2009 to
June, 2011.
4.17
82
Concentration of heavy metals in water (mg/L) of four regions
in The Sultanate of Oman during November, 2009 to July,
2010.
4.18
83
Correlations of plots of concentration of Ni (a) in soil and plant
(b) in soil and water and (c) in plant and water
86
xvii
LIST OF GLOSSARY
AAS
Atomic Absorption Spectrometry
FAAS
Flame Atomic Absorption Spectrophotometer
GPS
Global Positioning System.
GFAAS
Graphite Atomic Absorption Spectrophotometer
ICP-OES
Inductively Coupled Plasma- Optical Emission
spectrometry.
PTWIs
Provisional Tolerable Weekly Intakes
PMTDIs
Provisional Maximum Tolerable Daily Intakes
JECFA
Joint Expert Committee on Food Additives
FAO
Food and Agriculture Organization
MPL
Maximum Permissible Level
TN
Total Nitrogen
USEPA
United State Environmental Protection Agency
WHO
World Health Organization