UNIVERSITI TUN HUSSEIN ONN MALAYSIA

STATUS CONFIRMATION FOR MASTER’S THESIS ELECTROKINETIC-ASSISTED PHYTOREMEDIATION OF HEAVY METAL

IN RIVERBANK SOIL

ACADEMIC SESSION : 2015/2016 I, SUHAILLY BINTI JAMARI, agree to allow this Master’s Thesis to be kept at the Library under the following terms: 1. This Master’s Thesis is the property of the Universiti Tun Hussein Onn Malaysia. 2. The library has the right to make copies for educational purpose only. 3. The library is allowed to make copies of this report for educational exchange between higher

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Approved by,

(WRITER’S SIGNATURE) (SUPERVISOR’S SIGNATURE) ASSOC. PROF. DR.ZAIDI BIN EMBONG

Permanent Address: D16, KAMPUNG PARIT RAJA AHMAD,

83500 PARIT SULONG, BATU PAHAT,

JOHOR DARUL TAKZIM.

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ELECTROKINETIC-ASSISTED PHYTOREMEDIATION OF HEAVY METAL IN

RIVERBANK SOIL

SUHAILLY BINTI JAMARI

A thesis submitted in

fulfillment of the requirement for the award of the Degree of

Master of Science

Faculty of Science, Technology and Human Development

Universiti Tun Hussein Onn Malaysia

JUNE 2016

ii

I hereby declare that the work in this thesis is my own except for quotations and

summaries which have been duly acknowledged

Student : ...........................................................

SUHAILLY BINTI JAMARI

Date : ...........................................................

Supervisor : ...........................................................

ASSOC. PROF. DR. ZAIDI BIN EMBONG

iii

For my beloved family

Muhammad Syazwan bin Shariffudin Sasidharan

Muhammad Zhariff Zhakwan bin Muhammad Syazwan

Muhammad Zhariff Zhafran bin Muhammad Syazwan

Saodah binti Sapuan

Shariffudin Sasidharan bin Abdullah

Rohana binti Haron

And all my family members

iv

ACKNOWLEDGEMENT

Bismillahirrahmanirrahim

The whole journey of this study was conducted to prove that EK technique does

contribute to the improvement of phytoremediation method. In 2012, the study was

started by selecting the suitable sampling site and collecting soil samples at the Sedi

River with the endless support of my supervisor; Associate Professor Dr. Zaidi bin

Embong, and fieldwork assistant; Mr. Mohd. Hanafi bin Mokhtar. Despite of his

disability, Associate Professor Dr. Zaidi bin Embong tirelessly taught and guided me on

how the study should be done.

The whole year of 2013 was spent on conducting the EK assisted phytoremedition

study and in year 2014, the treated soil and plant samples were completely analyzed. The

challenges in sample analysis process were to meticulously prepare the samples prior to

analysis which sometimes took almost ten times of repetitions. The limited number of

analyses equipments versus high number of students using it was also delaying the lab

work. There was one time where the sample analysis process was delayed for almost two

months due to equipment malfunction. Year 2015 was spent on analyzing the data and

results obtained from the sample analysis processes. After all blood, sweat and tears, the

findings of this study were compiled in this thesis. Therefore, I would like to express my

earnest gratitude to my supervisor, Assoc. Prof. Dr. Zaidi bin Embong for his way of

guidance, supervision and support throughout my research. My appreciation also goes to

Mr. Mohd. Hanafi bin Mokhtar for assisting me in fieldwork tasks. I would also like to

extend my appreciation to:

- Physics Laboratory 3 (FSTPi) staff; Mr. Asrul and Mr. Iskandar

- RECESS staff; Mdm Salina Sani, Mr. Amir Zaki and Mr. Mudzaffar Syah

v

- Environmental Analysis Laboratory (FKAAS) staff; Mdm Nadiah, Mdm

Fazliana and Mr. Redzuan

- Materials Science Laboratory (FKMP) staff; Mr. Tarmizi and Mr. Anuar

- RECESS postgraduates members

My family occupies a special place in this acknowledgement. I find no words to

express my appreciation to my dearest husband and sons; Muhammad Syazwan bin

Shariffudin Sasidharan, Muhammad Zhariff Zhakwan bin Muhammad Syazwan and

Muhammad Zhariff Zhafran bin Muhammad Syazwan for their love, patience and

everlasting support, together with my mother, my parents in laws and all my family

members.

Not to forget, I would like to express my gratitude to the government as this work

was funded by the Ministry of Higher Education of Malaysia under the Exploratory

Research Grant Scheme Vot. E008 entitled “Electrokinetic-assisted Phytoremediation of

Heavy Metal in Riverbank Soil”.

To finish, I thank Allah for His grace, mercy and love that I could be at this point

of my life. I am aware that although I have been far from Him for so many times, but He

has always been with me. Thank you Allah.

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ABSTRACT

Electrokinetic (EK)-assisted phytoremediation is one of the environmental remediation

methods that have a big potential in enhancing the ability of plant heavy metal uptake in

soils. This study was conducted to investigate the difference in heavy metal composition

concentration of riverbank soil and the change of soil pH between pre and post

phytoremediation and EK assisted phytoremediation treatment. The selected

phytoremediation plant is Dieffenbachia ‘Tropic Rain”. The phytoremediation plant

treatment was fertilized with organic and chemical fertilizer while the EK

phytoremediation plant was induced with EK system (a pair of EK electrodes connected

to a direct current (DC) power supply with a magnitude of 6 V/cm-1 electric field) for 4

hours/day. The soil and plant samples from pre and post treatments were analyzed using

and X-ray Fluorescence Spectrometer (XRF), Scanning Electron Microscope / Energy

Dispersive X-ray Spectroscopy (SEM/EDX) and Inductively Coupled Plasma Mass

Spectrometer (ICP-MS). After 12 months of EK assisted phytoremediation treatment, the

soil pH near the cathode increase 48.8% from pH 4.32 to pH 6.43 while in anode region

the pH decrease 28% from pH 4.32 to pH 3.11. The element concentrations in cathode

region for most elements of interest (Ni, Cu, Zn, As and Pb) were higher than anode and

middle region with the highest is (47.3 ± 0.6) ppm Pb. The elemental concentration of Ni,

Cu, Zn, As and Pb by EK assisted phytoremediation plants were slightly higher than the

elements absorbed by the phytoremediation treated plants alone in the “chemical” and

“organic” slots with the highest is (7.98 ± 0.68) ppb Zn. This showed that the EK assisted

remediation treatment has increased the plant’s absorption during the phytoremediation

process.

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ABSTRAK

Pemulihan fito berelektrokinetik (pemuliharaan fito EK) adalah salah satu langkah

pemulihan alam sekitar yang mempunyai potensi yang besar untuk meningkatkan

keupayaan penyerapan logam berat oleh pokok dalam proses pemuliharaan tanah. Kajian

ini dijalankan untuk mengkaji kepekatan komposisi logam berat di dalam tanah tebing

sungai dan perubahan dalam pH tanah menggunakan teknik pemuliharaan fito dan teknik

pemulihan fito EK. Pokok yang dipilih untuk kajian ini adalah Dieffenbachia ‘Tropic

Rain”. Untuk teknik pemulihan fito, pokok dibajai dengan baja organik dan kimia

manakala teknik pemulihan fito EK dibekalkan dengan sistem EK yang mengandungi

sepasang elektrod yang disambung kepada punca kuasa arus terus (DC) dengan medan

elektrik sebanyak 6 V/cm-1 selama 4 jam sehari. Sampel tanah dan pokok dianalisa

menggunakan Spektrometer Pendafluor Sinar-X (XRF), Mikroskop Imbasan Elektron /

Spektrometer Sinar-X Sebaran Tenaga (SEM/EDX) dan Spektrometer Jisim Terganding

Plasma Beraruh (ICP-MS). Selepas 12 bulan rawatan pemulihan fito EK, pH tanah

kawasan katod meningkat 48.8% daripada pH 4.32 ke pH 6.43. pH tanah di kawasan

anod menurun 28% daripada pH 4.32 ke pH 3.11. Kepekatan unsur Ni, Cu, Zn, As dan

Pb di katod lebih tinggi berbanding anod dan kawasan tengah dengan kepekatan tertinggi

ialah (47.3 ± 0.6) ppm Pb. Kepekatan unsur Ni, Cu, Zn, As dan Pb yang terserap di dalam

pokok yang di rawat dengan teknik pemulihan fito EK didapati lebih tinggi daripada

unsur di pokok dengan rawatan teknik pemulihan fito sahaja (di dalam slot “kimia” dan

“organik”) dengan nilai paling tinggi adalah (7.98 ± 0.68) ppb Zn. Hal ini menunjukkan

bahawa teknik pemulihan fito EK berjaya membantu penyerapan unsur oleh pokok

semasa proses pemulihan fito.

viii

CONTENTS

TITLE i

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT vi

ABSTRAK vii

CONTENTS viii

LIST OF TABLES xii

LIST OF FIGURES xiv

LIST OF SYMBOLS AND ABREVIATIONS xviii

LIST OF EQUATIONS xx

LIST OF APPENDIXES xxi

CHAPTER 1 INTRODUCTION 1

1.1 Background of the Study 1

1.2 Problems Statement 3

1.3 Aim and Objectives of the Study 4

1.4 Scope of Study 5

1.5 Significance of Study 6

1.6 Structure of Thesis 6

CHAPTER 2 LITERATURE REVIEW 8

2.1 Introduction 8

2.2 The Issues of River Contamination Worldwide 9

2.3 The Issues of River Contamination in Malaysia 17

2.4 Remediation Techniques on Heavy Metals-Contaminated Soil

And Sediment 19

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2.4.1 Amendment 20

2.4.2 Sandcap 21

2.4.3 Washing 22

2.5 Phytoremediation 23

2.5.1 Techniques of phytoremediation 24

2.5.2 Mechanism of ion movement from soil to root 26

2.5.3 Ion absorption by plants 27

2.5.4 Hyperaccumulator 29

2.5.5 Phytoremediation plant candidate 31

2.6 Electrokinetics remediation 34

2.6.1 Electrokinetics transport processes 34

2.6.2 Physico-chemical processes in electrokinetics

remediation 36

2.7 Electrokinetic-Assisted Phytoremediation 39

2.8 Summary of Chapter 45

CHAPTER 3 METHODOLOGY OF RESEARCH 47

3.1 Introduction 47

3.2 Sampling Site Determination 48

3.2.1 Three potential sites 48

3.2.1.1 Sedi River, Yong Peng 49

3.2.1.2 Sembrong River, Kampung Sawah Sagil 50

3.2.1.3 Batu Pahat River, Batu Pahat 50

3.2.2 The equipments for sampling site determination 51

3.2.2.1 Ludlum Model 19 MicroR survey meter 52

3.2.2.2 Soil pH and Moisture Tester (DM-15) Takemura

Japan Test 53

3.2.3 Soil sample assessment and site determination 53

3.3 Soil Sample Collection 55

3.4 Phytoremediation Plant Candidate 57

3.5 Phytoremediation Reactor 57

3.6 Electrokinetics (EK) Set-up 60

x

3.6.1 The equipment for electrokinetic (EK) set-up 61

3.6.1.1 DC power supply (GW Instek

model GPR-11H30D) 62

3.7 Phytoremediation Observation 62

3.8 Sample Preparation 63

3.8.1 Sample for soil pH analysis 63

3.8.2 Sample for soil elemental composition analysis 63

3.8.3 Sample for plant elemental composition analysis 67

3.8.4 The equipments for sample preparation 71

3.8.4.1 Fritsch Planetary Mono Mill Pulverisette 6 71

3.8.4.2 Breitlander Laboratory Press PE-MAN 72

3.8.4.3 Favorit Stirring Hotplate HS0707V2 74

3.9 Sample Analysis 74

3.9.1 Soil pH analysis 75

3.9.2 Soil elemental composition analysis 75

3.9.2.1 XRF analysis for soil sample 76

3.9.2.2 SEM/EDX analysis for soil sample 77

3.9.3 Plant elemental composition analysis 78

3.9.3.1 SEM/EDX analysis for plant sample 78

3.9.3.2 ICP-MS analysis for plant sample 79

3.9.4 The equipments for sample analysis 80

3.9.4.1 Lutron Pen pH Meter Model PH-222 80

3.9.4.2 Bruker AXS S4 Pioneer 81

3.9.4.3 EDX spectrometer model JEOL JSM-6380-LA 82

3.9.4.4 ICP-MS (Perkin-Elmer Sciex model ELAN

9000) 83

3.10 Data Analysis 84

3.11 Summary of Chapter 84

CHAPTER 4 RESULTS AND ANALYSIS 86

4.1 Introduction 86

4.2 The changes of riverbank soil pH 87

xi

4.2.1 Comparison of soil pH between pre and post

phytoremediation and post EK assisted phytoremediation

treatments 88

4.3 Heavy metals mobility in riverbank soil 91

4.3.1 XRF analysis for soil samplesof pre and post

phytoremediation and post EK assisted

phytoremediaton treatment 91

4.3.2 SEM/EDX analysis for soil samples of pre and post

phytoremediation and post EK assisted

phytoremediaton treatment 98

4.3.3 Comparison between XRF and SEM/EDX

analyses on riverbank soil samples 104

4.4 The absorption of heavy metals by phytoremediation plants 110

4.4.1 SEM/EDX analysis for plant powder samples of pre and

post phytoremediation and post EK assisted

phytoremediaton treatment 110

4.4.2 ICP-MS analysis for plant samples of pre and post

phytoremediation and post EK assisted

phytoremediaton treatment 116

4.4.3 Comparison between SEM/EDX and ICP-MS

analyses on phytoremediation plant samples 121

4.5 Summary of Chapter 126

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS 127

5.1 Conclusions 127

5.2 Recommendations 128

REFERENCES 130

VITA 139

APPENDIX 140

xii

LIST OF TABLES

Table 1.1: Summary of some different remediation process 4

Table 2.1: Anthropogenic sources of several heavy metals in the environment 9

Table 2.2: Harmful effects of several heavy metals on human health 15

Table 2.3: Summary of the different techniques of phytoremediation process 25

Table 2.4: Several hyperaccumulator plant species and their metal-

accumulating capacities 30

Table 2.5: Summary of laboratory studies of EK assisted phytoremediation 45

Table 3.1: Site coordinates, soil and river water pH and environmental radiation

dose-rate readings 54

Table 3.2: Elemental composition data of the three sites using XRF analysis 55

Table 4.1: Soil pH for pre and post phytoremediation and post EK assisted

phytoremediation treatment 88

Table 4.2: Soil elemental concentration of Ni, Cu, Zn, As and Pb for pre

and post phytoremediation and post EK assisted phytoremediation

treatment by XRF analysis 92

Table 4.3: Soil elemental concentration of Ni, Cu, Zn, As and Pb for pre and

post phytoremediation and post EK assisted phytoremediation treatment

by SEM/EDX analysis 99

Table 4.4: Plant elemental concentration of Ni, Cu, Zn, As and Pb for pre

and post phytoremediation and post EK assisted phytoremediation

treatment by SEM/EDX analysis 111

Table 4.5: Plant elemental concentration of Ni, Cu, Zn and Pb for pre

and post phytoremediation and post EK assisted phytoremediation

xiii

treatment by ICP-MS analysis 117

xiv

LIST OF FIGURES

Figure 1.1: Heavy metal contamination in river system 2

Figure 1.2: The transport mechanism of heavy metal in the environment 3

Figure 2.1: Typical macroinvertebrates in different substrata 12

Figure 2.2: Heavy metals accumulation route 14

Figure 2.3: One of Minamata disease effect 17

Figure 2.4: The sample collection of Pahang River water for potential bauxite

mining pollution 18

Figure 2.5: The work of sand cap remediation technique 21

Figure 2.6: Typical process diagram of soil washing remediation technique 22

Figure 2.7: Techniques of phytoremediation process 24

Figure 2.8: Cross section of a plant root. Site of passive uptake is the apparent

free space which is outside the Casparian strip in the cortex 27

Figure 2.9: Diagram of a plant cell. Active uptake occurs at the plasmalemma 28

Figure 2.10: The plants use in the phytoremediation techniques : Dumb cane

(Dieffenbachia ‘Tropic Rain’) 32

Figure 2.11: Application of EK in the contaminated soil 35

Figure 2.12: EK assisted phytoremediation system 39

Figure 2.13: Schematic diagram of the electrodic phytoremediation system 40

Figure 2.14: A photo of ryegrass plant 41

Figure 2.15: A photo of (a) rapeseed (Brassica napus), and (b) tobacco

(Nicotiana tabacum) 42

Figure 2.16: The schematic diagram of the pot experiment 43

xv

Figure 2.17: The schematic diagram of lead removal from contaminated soil by

electrokinetic-assisted phytoremediation system 44

Figure 3.1: Three location of sampling sites; (i) Sedi River, (ii) Sembrong River,

(iii) Batu Pahat River 49

Figure 3.2: Google Streetview image of Sedi River from Jalan Besar, Yong Peng 49

Figure 3.3: Soil sampling work at Sembrong River, Kampung Sawah Sagil 50

Figure 3.4: Soil sampling work at Batu Pahat River, Batu Pahat 51

Figure 3.5: The portable Ludlum Model 19 MicroR Meter (left) and Soil pH

and Moisture Tester (DM-15) Takemura Japan Test (right) 52

Figure 3.6: The background radiation dose-rate measurement 52

Figure 3.7: The soil pH measurement using pH meter 53

Figure 3.8: The sampling site at Sedi River 55

Figure 3.9: Soil sample collection at the riverbank 56

Figure 3.10: The collected riverbank soil samples using clay pots 56

Figure 3.11: The phytoremediation reactor 57

Figure 3.12: A schematic design of phytoremediation reactor : (a) side view

of the reactor and (b) top view of the reactor. 58

Figure 3.13: The sequence order of the slot on the phytoremediation reactor 59

Figure 3.14: Two types of fertilizers used in this study; a) chemical (inorganic)

fertilizer, and b) organic fertilizer 60

Figure 3.15: The EK set-up 61

Figure 3.16: The DC power supply (GW Instek model GPR-11H30D) 62

Figure 3.17: The oven (model Memmert) 64

Figure 3.18: (a) The collected soil sample from cell, (b) The oven dried soil sample 64

Figure 3.19: The Fritsch Planetary Mono Mill Pulverisette 6 65

Figure 3.20: The ground soil sample in the grinding bowl 65

Figure 3.21: Endecotts Lab Test Sieve 50 µm 66

Figure 3.22: The Breitlander Laboratory Press PE-MAN and die sets 67

Figure 3.23: The pellets of soil samples for XRF analysis 67

Figure 3.24: The decontaminated plant samples; a) organic plant sample,

b) EK assisted phytoremediation plant sample, and c) chemical

xvi

plant sample 68

Figure 3.25: The samples heated on hot plate for nitric-perchloric acid digestion 70

Figure 3.26: Whatman Filter Paper No. 5 71

Figure 3.27: The working principle of the grinder 72

Figure 3.28: The Breitlander Laboratory Press PE-MAN 73

Figure 3.29: Die sets for Breitlander Laboratory Press PE-MAN 73

Figure 3.30: Favorit Stirring Hotplate HS0707V2 74

Figure 3.31: The pH measurement using Lutron Pen pH Meter Model PH-222 75

Figure 3.32: The XRF spectrometer (Bruker AXS S4 Pioneer) 76

Figure 3.33: a) Carbon conductive tape, b) The sample on stub for SEM/EDX

analysis 77

Figure 3.34: Typical EDX spectrum of soil sample 78

Figure 3.35: The ICP-MS (Perkin-Elmer Sciex model ELAN 9000) spectrometer 79

Figure 3.36: Lutron Pen pH Meter Model PH-222 80

Figure 3.37: Bruker AXS S4 Pioneer 81

Figure 3.38: EDX spectrometer model JEOL JSM-6380-LA 82

Figure 3.39: The ICP-MS schematic 83

Figure 4.1: The trend of soil pH for pre and post phytoremediation and post EK

assisted phytoremediation treatment 90

Figure 4.2: Soil elemental concentration of; (a) Ni, (b) Cu, (c) Zn, (d) As and

(e) Pb for pre and post phytoremediation and post EK assisted

phytoremediation treatment by XRF Analysis 94

Figure 4.3: Soil elemental concentration of; (a) Ni, (b) Cu, (c) Zn, (d) As and

(e) Pb for pre and post phytoremediation and post EK assisted

phytoremediation treatment by SEM/EDX Analysis 101

Figure 4.4: Comparison between elemental concentrations of; (a) Ni, (b) Cu, (c) Zn,

(d) As and (e) Pb by XRF and SEM/EDX analyses on riverbank soil

samples 105

Figure 4.5: Plant elemental concentration of; (a) Ni, (b) Cu, (c) Zn, (d) As and

(e) Pb for pre and post phytoremediation and post EK assisted

phytoremediation treatment by SEM/EDX Analysis 112

xvii

Figure 4.6: Plant elemental concentration of; (a) Ni, (b) Cu, (c) Zn, (d) Pb for

pre and post phytoremediation and post EK assisted

phytoremediation treatment by ICP-MS Analysis 119

Figure 4.7: Comparison between elemental concentrations of; (a) Ni, (b) Cu,

(c) Zn and (d) Pb by SEM/EDX and ICP-MS analyses on

phytoremediation plant samples 122

xviii

LIST OF SYMBOLS AND ABREVIATIONS

EK electrokinetics

XRF X-ray Fluorescence

SEM/EDX Scanning Electron Microscopy / Energy Dispersive X-ray

ICP-MS Inductively Coupled Plasma Mass Spectrometer

Ni Nickel

Cu Copper

Zn Zinc

As Arsenic

Pb Plumbum/lead

Z Atomic number

EDTA ethylenediamine tetracetic acid

EGTA ethylene glycol-bis-[2-aminoethylether]-N,N,N,N, tetracetic acid

EDDS SS-ethylene diaminedisuccinic acid

C carbon

H hydrogen

O oxygen

RECESS, UTHM Research Centre for Soft Soil, Universiti Tun Hussein Onn Malaysia

FKAAS, UTHM Faculty of Civil and Environmental Engineering, Universiti Tun

Hussein Onn Malaysia

HNO3 nitric acid

H2SO4 sulphuric acid

HClO4 perchloric acid

H2O2 hydrogen peroxide

xix

Si Silicon

Hg Mercury

Se Selenium

ppm parts per million

ppb parts per billion

xx

LIST OF EQUATIONS

NO. EQUATION PAGE

2.1 2H2O ↔ 4H+ + O2 + 4e- 36

2.2 4H2O + 4e- ↔ 4OH- + 2H2 36

3.1 T-test =

−−

1nSµχ

84

3.2 χ =

Σ

nx

84

3.3 S2 = ∑ −

−)( 2

11 χxn or S2 = ∑ − )( 21 χxn 84

xxi

LIST OF APPENDIXES

APPENDIX TITLE PAGE

A X-ray Micro-Analysis of Trace Elements (Ni, Cu, Zn)

Composition in Riverbank Soil by Electrokinetic-

Assisted Phytoremediation 140

B Elemental Composition Study of Heavy Metal (Ni, Cu, Zn) in

Riverbank Soil by Electrokinetic-Assisted Phytoremediation using

XRF and SEM/EDX 146

C XRF And EDX Analysis of Trace Element In River Bank Soil

By The Effect of Electrokinetic-Assisted Phytoremediation 153

D DC power supply (GW Instek model GPR-11H30D) 159

E Fritsch Planetary Mono Mill Pulverisette 6 182

F Breitlander Laboratory Press PE-MAN 190

G Lutron Pen pH Meter Model PH-222 192

H ICP-MS (Perkin-Elmer Sciex model ELAN 9000) 194

CHAPTER 1

INTRODUCTION

1.1 Background of the Study

Nowadays, heavy metals originating from anthropogenic activities are frequently detected in

sediments and water columns of river/lake, which cause a considerable number of the world’s

rivers/lakes severely contaminated. There are two classifications of heavy metal which are

essential and non-essential to the biological systems of living organism. Essential heavy

metals are necessary biological function of living organism while non-essential heavy metals

have no importance in living organisms (Ali, Khan &Sajad, 2013).

Anthropogenic activities are including mining, smelting, electroplating, agriculture

and etc. The contaminationcaused by the industrial and agricultural activities has been

emphasized in studies around the world due to the adverse biological effects on the health of

the aquatic environment. The effects are including aquatic life mortality and

immobilization.Figure 1.1 shows the heavy metal contamination in the river due to

anthropogenic activities. The fishes are dead due to high concentration of heavy metals in the

river water. Clearly, with this condition of river, it could be concluded that it is not safe for

human consumption.

The buildup of potentially toxic metals carries a huge risk to the beneficial uses and

sustainability of the natural resources such as water, plants and aquatic animals (Duan et

al.,2009; Ezemonye, Ogeleka, &Okieimen, 2009; Sultan &Shazili, 2010) and furthermore

could risk the life of human being. The migration of particle-reactive heavy metals from

riverbank sediment into bottom sediment through water diffusion may quickly adsorb onto

2

suspended matter and ultimately move to bottom sediment. In aquatic environment, heavy

metal is usually distributed as follows: water-soluble species, colloids, suspended forms and

sedimentary phases. However, heavy metals could not be removed by natural processes of

decomposition like organic pollutants does (Penget al., 2008).

Figure 1.1: Heavy metal contamination in river system(Glennie& Cox, 2014)

As heavy metals usually possess significant toxicity to aquatic organisms and affect

human health through food chain, therefore, riverbank soil /riverbank sediment remediation

need to be considered as the priority in order to reduce or prevent the heavy metal migration

into the river stream system.To clean up the heavy metal contamination in riverbank sediment

system, various techniques of remediation are able to be applied on the sites depending on the

condition and severity of the contamination level.

Some of the techniques are sand cap remediation technique, electrochemical

technique, excavation and bioremediation technique, just to name a few. However, an

extensive eco-technological technique such as phytoremediation can be a potential

remediation options for the existing areas of land disposed dredged sediments and for the

future treatment of the large volumes of contaminated dredged sediments. Figure 1.2 shows

the transport mechanism of heavy metal in the environment.

3

Figure 1.2: The transport mechanism of heavy metal in the environment(Sagasiki

Environmental Developments Co.,Ltd, 2002 )

1.2 Problems Statement

Contamination of inorganic metal in river, estuarine and marine sediment by anthropogenic

activities are frequently detected and risking the aquatic life. This irresponsibility act could

also threaten the life of human being. Besides mortality, heavy metal contamination could let

human being end up with various health problems such as dysfunctional of physical abilities,

mental problem and permanent handicap.Salem, Eweida, and Farag (2000) found the

relationship between high heavy metals concentration in drinking water and health problem in

human being in their study in Great Cairo Cities. The consumed heavy metals contaminated

drinking water lead to renal failure, hair loss, liver cirrhosis, and chronic anemia.

Realized with the seriousness of these issues, researchers all over the world has

conducted experiments and studies on how to restore or remediate the contaminated site to its

original condition, or at least to reduce the dreadful condition to a better state. The types of

remediation techniques were implemented depends on many factors such as the suitability of

the technique with the contaminated site, the types of heavy metal to be remediate, the cost

4

needed to conduct the study and many more. Table 1.1 summarized some of the common

remediation technique for heavy metal contamination.

Table 1.1: Summary of somedifferent remediation process(Peng, et al., 2008)

Phytoremediation is a developing innovative technique which uses living green plants

for reduction and/or removal of contaminants from contaminated soil, water, sediments, and

air. The main advantage of phytoremediation is it is low expense and can be used for in situ

application in large scales. As the plant could not rapidly absorb the increased soluble heavy

metals in riverbank sediment solution in a short time, another remediation technique needs to

be combined with this technique to improve the heavy metal absorption by the plant (Ali et

al., 2013; Anjum et al., 2013; Raskin& Ensley, 2000).

Therefore, a suitable remediation technique needs to be developed to control the risk

of heavy metals leaching into river stream system, as well as to decrease the heavy metal

mobility in sediment and uptake by marine life. This could be achieved by applying a new

remediation technique which uses a combination of phyto- and electrokinetic (EK) -

remediation, known as “EK AssistedPhytoremediation”. This new remediation technique will

also provide an alternative eco-technological technique to prevent the heavy metal in

riverbank soil from leaching into the river stream which can accumulate in sediment.

1.3 Aim and Objectivesof the Study

Remediation process Description

Amendments Decrease metal mobility and bioavailability by precipitation or sorption

Washing Heavy metals are shifted from the dredged sediment to washing solution such as acid washing, chelating agents or surfactant

Sand cap

Capping the contaminated sediment with sandy material, such as clean sediment, sand or gravel to decrease the direct contact between water and the contaminated sediment

Electrochemical remediation

Application of low DC current to electrodes which inserted to sediment and decontaminates the area

Phytoremediation The use of plant to detoxify contaminants

5

This study was conducted with the aim to reduce the heavy metal contamination in the river

system through EK-assisted phytoremediation technique. By applying this technique to the

riverbank of river, the problem of heavy metal leaching into the river systems could be control

thus reducing the mobility of heavy metal in sediment and uptake by marine life. There are

several things to be monitored during the study which are the change of soil pH and the

concentration of heavy metal in soil and plant for pre and post treatment. Thus, the following

objectives are to be achieved in order to fulfill the aim of the study;

a) To investigate and analyze the changes on the riverbank soil pH influencedbyEK

assisted phytoremediation treatment.

b) To study and analyze the improvement of heavy metal mobility in the riverbank soil

with the assistance of EK technique.

c) To compareand critically analyze the increase of heavy metal absorption in

Dieffenbachia ‘Tropic Rain’ between EK assisted phytoremediation treatment and

ordinaryphytoremediation treatment.

1.4 Scope of Study

This study was conducted as a response to the increase of heavy metal contamination in the

environment not only in Malaysia but up to worldwide level. It focuses on the physico-

chemical changes in the ex-situ phytoremediation of the riverbank soil with the aim to reduce

the heavy metal leaching into the river system and decreasing the heavy metal mobility in

sediment. Initially, three soil samples from three potential sampling sites in the area of Batu

Pahat rivers were collected. They are Sedi River, Yong Peng, Batu Pahat River, Batu Pahat

and Sembrong River, Kampung Sawah Sagilin which they have a close proximity to industrial

factories, residential area and agricultural activities.

Assessment of heavy metal concentration by X-Ray Fluoresence (XRF) analysis were

conducted on those samples. The selected sampling site, which is Sedi River, Yong Peng, was

determined from the assessment by which sample has the highest concentration of heavy

metal among all. The phytoremediation technique was conducted on the collected Sedi River

soil samples and assisted by EK techniques in order to improve the heavy metal absorption

capability by the phytoremediation plant; Dieffenbachia ‘Tropic Rain’ in the contaminated

6

riverbank soil environments. Dieffenbachia ‘Tropic Rain’ is selected as the phytoremediation

plant because they are abundant and grows well with no signs of deterioration in the sampling

area.

The study was conducted for 12 months duration. In this study, the soil and plant

composition were examined using various types of chemical analytical methods such as X-

Ray Fluoresence (XRF), Scanning Electron Microscopy/Energy Dispersive X-ray

spectroscopy (SEM/EDX) and Inductively Coupled Plasma Mass Spectrometer (ICP-MS). It

is expected that this studycan lead to the establishment of noble eco-technology remediation

technique which provides a “phytoremediation barrier” along the riverbank that capablein

reducing the heavy metal mobility into the river stream.

1.5 Significance of Study

River contamination is currently one of the major issues that need to be solved promptly. As

there are various types of remediation techniques for contaminated soil and river, the results

or findings of this study could give a better understanding on the concept of EK assisted

phytoremediation treatment. The implementation of EK assisted phytoremediation treatment

using tropical plant; Dieffenbachia ‘Tropic Rain’ could fulfill the aim to reduce the heavy

metal concentration in riverbank contaminated soil and establish a new retarding mechanism

of heavy metal ion mobility from the riverbank soil to the river stream. By reducing the heavy

metal leaching into the river system, the water quality of the river is able to be improved and

safer for human consumption. It is not only beneficial to human, but also to other living

organism and aquatic life.

1.6 Structure of Thesis

There are a total offive chapters consisted in this thesis including this introductory chapter.

They are introduction, literature review, methodology of research, results and analysis and

conclusions and recommendations chapters. The summary of each chapters are described as

follow:

a) Chapter 1: Introduction

7

This chapter gives details on the background of the study, problem statements,

research aims and objectives, scope of the study and the contribution of this

study.Some highlighted issuesof heavy metal contamination in environment are also

included in this chapter.

b) Chapter 2: Literature Review

This chapterpinpointed the international and national issues of heavy metal

contamination in the environment, especially the river contamination issues. The

history of remediation methods implemented to overcome the problem of

environmental contamination is also reviewed. Lastly, the focus of the review is on

EK-assisted phytoremediation technique which is conducted in this study and listed

the relevant history of EK-assisted phytoremediation experiments to the study.

c) Chapter 3: Methodology of Research

The chapter described how the study was conducted. The process of determining

Sedi River as the sampling site, the sample collection process andthe construction of

phytoremediation reactor was explained in detail. Moving further into the chapter,

the discussion was about thesoil and plant sample preparation which include the

process of turning the soil sample into powder and pellet form and preserving plant

sample by acid digestion method. The sample analysis process whichwereperformed

in this study using XRF spectrometer, SEM/EDX spectrometer and ICP-MS

spectrometer. The descriptions of all equipments utilized in this study were also

discussed.

d) Chapter 4: Results and Analysis

This chapter focuseson the obtained results from the phytoremediation and EK

assisted phytoremediation treatments based on the soil pH as well as soil and plant

elemental concentrations data analysis and discussing the early conclusions from the

findings.The soils were analyzed by means of XRF and SEM/EDX and plant

samples were analyzed using SEM/EDX and ICP-MS.

e) Chapter 5: Conclusions

This chapter provides conclusions of the study and determining whether the results

that were obtained in Chapter 4 achieving the three objectives of the study.

8

Limitations and recommendations of future work are also described as to improve

the future study.

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

The need for implementing a meticulous literature review is very crucial in any research. In

this chapter, the focal points of the discussion in the early sections are concerning the

enhancement of environmental contamination issues from year to year. This chapter is

critically discusesthis serious issue which does not only occur in Malaysia but up to

worldwide level.The source of the contamination; heavy metals, are discussed in the sections

and pinpoint the route of heavy metals pathway to the environment. The heavy metals

contamination issue does not only affected the environment, but also threatening human life.

Thus, the effects of heavy metals contamination to the water column of river, aquatic life and

most importantly human are also discussed in the chapter.

The chapter discussesfurther on the remediation methods employed by the authorities

and environmental professionals to overcome the crisis. There are various remediation

techniques to be employed depending on the condition of the contamination, location site of

the contamination, types of contaminants involved and the suitability of the method to the

solve the particular contamination issue. In this chapter, it illustrated and discussed some

remediation methods, including the one that was selected for this research; electrokinetic

(EK)-assisted phytoremediation method which have more advantages than the other method

9

and more suitable to be applied in this study. The explanation of the selected method is

discussed further in the last sections.

2.2 The Issues of River Contamination Worldwide

Heavy metalsmigrateinto the ecosystem from natural and anthropogenic sources(Ali, et al.,

2013). Anthropogenic sources of heavy metal from agriculture, mining, smelting,

electroplating, and other industrial activities have resulted in the accumulation of detrimental

concentration of metal such as As, Cd, Cr, Cu, Ni, Pb and Zn in soil (Raskin & Ensley, 2000).

Heavy metals are classified as essential and non-essential in terms of their role in biological

systems. Essential heavy metals such as Fe, Mn, Cu, Zn and Ni are necessary and needed for

vital physiological and biological function of living organismwhile non-essential heavy

metals such as Cd, Pb, As, Hg and Cr are not needed by living organisms (Ali, et al., 2013).

Table 2.1 listed the anthropogenic sources of several heavy metals in the environment.

Table 2.1: Anthropogenic sources of several heavy metals in the environment(Ali, et al.,

2013)

Heavy metal Sources As Pesticides and wood preservatives

Cd Paints and pigments, plastic stabilizers, electroplating, incineration of cadmium-containing plastics, phosphate fertilizers

Cr Tanneries, steel industries, fly ash Cu Pesticides, fertilizers

Hg Release from Au–Ag mining and coal combustion, medical waste

Ni Industrial effluents, kitchen appliances, surgical instruments, steel alloys, automobile batteries

Pb Aerial emission from combustion of leaded petrol, battery manufacture, herbicides and insecticides

The migration of particle-reactive heavy metals from the riverbank sediment into the

bottom sediment through water diffusion may quickly adsorb onto the suspended matter and

ultimately move to the bottom sediment. In aquatic environment, heavy metal is usually

spread out as follows: water-soluble species, colloids, suspended forms and sedimentary

10

phases(Peng, et al., 2008). Heavy metals may chemically or physically interact with the

natural compound, which changes their forms of existence in the environment. In general,

they may react with particular species, change oxidation states and precipitate (Dube, et al.,

2000). Heavy metals may be bound or absorbed by particular natural substances, which may

increase or decrease their mobility.

The transport mechanism of heavy metals through soil has long presented great

interest to both environmental and soil scientists because of the possibility of groundwater

contamination through metal leaching. In general many soils contain a wide range of heavy

metals with varying concentration ranges depending on the surrounding geological

environment and anthropogenic and natural activities occurring or once occurred. Therefore,

in this research, there are five elements of interest to be studied which is Ni, Cu, Zn, As and

Pb. These metals are commonly present in soil essentially or non-essentially and explain

further as follow:

a) Copper, Cu is a transition metal in rosy-pink color with an atomic number of 29 and

an atomic weight of 63.54. Pure Cu is ductile with a melting point of 1083oC. Cu

majorly presents in the divalent oxidation state (Cu2+) in aqueous solution while some

exist as univalent compounds and complexes of Cu in nature (Wright & Welbourn,

2002). Its sorption reactions are pH dependence. pH stands for potential of hydrogen

(H+). It represents the negative log of the hydrogen ion (H+) concentration on the scale

from 0 to 14, with 7.0 indicates that the medium is in neutral state, less than 7.0 is

classified as “acidic” and greater than 7.0 is “ alkaline” (Jones, 2012). Cuis typically

dissolved well in acidic to neutral medium rather than in alkaline state. Thus, Cu is

fairly soluble in water(Wright & Welbourn, 2002). Anthropogenic activities such as

agricultural and waste disposal activity have deposited pesticides, fertilizer and

sewage sludge which mobilize Cu into the environment and contaminating soils and

water bodies (Khan, Ahmad, & Rahman, 2007).The mobility of Cu in soils is also pH-

dependence where it associates with the soil properties; Cu is highly mobile in acid

medium, fairly mobile in oxidising conditions and a very limited mobility in alkaline

conditions (Wright & Welbourn, 2002).

b) Zinc, Znis a relatively malleable, bluish-white chemical element with an atomic

number of 30. It has an atomic weight of 65.39,a melting point of 419.6oC, a boiling

11

point of 907oC anda density of 7.133 g cm-3(Anjum, et al., 2013).Zn is commonly

found in divalent oxidation state (Zn2+) and is composed of five stable isotopes. In

certain soils, Zn encompasses a high concentration level while in natural water, it

forms a fairly weak complex (hydrated Zn2+ at pH between 4 and 7)(Wright &

Welbourn, 2002).

c) Nickel, Ni is a soft, silvery-white metal with an atomic number of 28. Due to its high

ductility, fair strength and hardness and good thermal conductivity, Ni is easily

fabricated with steel–making procedure. Ni is a transition metal under group VIIIa. Its

prevalent valence states are 0 and +2 but majorly found as Ni2+ species. Pristine

streams, rivers and lakes contain a range of 0.2 – 10 mg L-1 total dissolved Ni, surface

water near Ni mines and smelters contain up to 6.4 mg L-1 while seawater contains

approximately 1.5 mg L-1(Wright & Welbourn, 2002). Interventions of Ni in

environment;particularly in water bodies are frequently due to industrial effluent; ghee

and oil, surgical instrument, steel alloys and automobile batteries industries (Tariq,

Ali, & Shah, 2006)

d) Arsenic, As is a chemical element with an atomic number 33, an atomic mass of 74.92

and a specific density of 5.73(Wright & Welbourn, 2002). As present in various

minerals, typically hand in hand with sulfur and other metals and also in a form of a

pure elemental crystal. Chemicals and glasses manufacturing and smelting process of

Cu, Zn and Pb had liberated As into the environment. The manufacturing of As-

contained pesticides releases As in a form of arsine gas. As in water bodies lead to

contamination of shellfish, cod and haddock(Anjum, et al., 2013). Other sources of As

in environment are paints, rat poisoning, fungicides and wood

preservatives(Thangavel & Subbhuraam, 2004).

e) Lead, Pb is a bright luster, bluish-white metal with an atomic number of 82 and an

atomic weight of 207. Pb is commonly used in metal product manufacturing due to its

high melting point (327.5oC) and its resistance towards corrosion. Pb exists naturally

in trace amount at an average of 20 ppm in Earth’s crust. It mobilized by the process

of weathering and volcanic emission and ultimately mobile by anthropogenic activities

(Wright & Welbourn, 2002). The typical state of Pb is inorganic compound state of

Pb(II). It can also being found as Pb(IV) which formed covalent compounds of

12

tetraalkylPb (tetraethyl Pb), used as an additive octane enhancer for gasoline for

years.Industry fields most commonly utilize Pb in battery manufacturing and they can

produce up to 2.5 million tons of Pb every year (Wright & Welbourn, 2002). Pb is

distributed in soils from natural geological sources and airborne particles; mostly

resulted from gasoline combustion. The smaller the Pb particle size is, the farther it is

being scattered, thus contaminating a widersurface area. As Pb compounds are rather

insoluble and extremely immobile in soils and sediments, the discharges from

industrial activities that are being channeled into the river streams tend to settle down

rapidly into the bed sediments. This state of affair may affect sediment-dwelling

organisms and worst; enter the food chain by this route (Khan et al., 2007; Wright

&Welbourn, 2002).

Contamination of inorganic metal in the river, estuarine and marine sediment by

anthropogenic activities have been frequently detected and have drawn massive attention to

researchers around the world due to the risk effects caused to the aquatic life. Freshwater and

streambed sediments are the primary refuge for aquatic life. Many species of aquatic life such

as invertebrates make algae and bacteria as their source of food. Some of them feed on leaves

and organic matters which enters the river. Vertebrates like fish gain food and energy from

freshwater benthic macroinvertebrates. Macroinvertebrates are animal with no backbones

which are larger than 0.5 mm. They play an essential role in aquatic ecosystems as they leave

behind nutrient when they die which are reusable by other animals and aquatic plants in the

food chain (Duan et al, 2009). Figure 2.1 shows a photo of typical microinvertebrates in

different substrata.

13

Figure 2.1: Typical macroinvertebrates in different substrata(Duan et al, 2009)

Shrimp is one of the benthic community members in Niger Delta ecological zone of

Nigeria and most rivers in the world. They are among the most sensitive invertebrates when it

comes to contaminants exposure. It was proved in a study conducted by Ezemonyeet al.(2009)

which evaluated the toxic effects of an industrial detergent (Neatex) on shrimp for10 daysof

exposure. At the end of the study, they found that the exposure of various concentration of

Neatex to the shrimps had resulted immobilization and mortality. The surviving organisms

frequently moved out of the sediment and swam erratically in the overlying water as a sign of

stress.As a conclusion, the surfactant-containing chemicals discharge into the water column;

whether it is accidentally or intentionally discharge,could possibly jeopardize environmental

sustainability of this ecologically important benthic species (Ezemonye et al., 2009).

In 2006 to 2007, Yi et al. (2008) have investigated the concentration of heavy metals

(Cr, Cd, Hg, Cu, Fe, Zn, Pb and As) in water, sediment, and fish/invertebrate in the middle

and lower reaches of the Yangtze River. The Yangtze River basin is severely contaminated

with 14.2 billion tons of waste water were discharged into it annually. Most of the waste

water is from industry and mining enterprises and the sewage of nearby cities where 80% of it

were discharged without proper treatment.In the study, they found that the heavy metal

concentration in sediment were higher than in the water by 100 to 10,000 times. On the other

hand, the concentrations of heavy metals in fish and invertebrate tissues were intermediate

between the sediment and the water samples.

The heavy metals concentration wasdistributed in the following order: bottom material

>demersal fish and benthic fauna > middle-lower layer fish > upper-middle layer fish >

water.Fish living near the river bed and making benthic invertebrates as their food source

possess a higher concentrations of heavy metals compared to fish living in the upper or

middle zones of the water column. The levels of Cu, Zn and Fe in fish were higher than Hg,

Pb, Cd, Cr, and As. This indicates that the fish are absorbing more necessary trace elements

(Cu, Zn and Fe) compared to the non-essentials elements.Heavy metals are accumulated

through the food chain via the following route: sediment - zoobenthos – benthonic sarcophagi

– human (Yi et al., 2008); as shown in Figure 2.2.

14

Figure 2.2: Heavy metals accumulation route (Yi et al, 2008)

The significance of the riverine, estuarine and marine sediment contamination by

inorganic metals has been emphasized in studies around the world due to the adverse

biological effects on the health of the aquatic environment. Contaminants originating from

urban, industrial and agricultural activities, atmospheric deposition and from natural

geological sources may accumulate in sediments up to several times the background

concentrations and may serve as the potential storage (> 90% of the heavy metal loads) for

both the inorganic and organic contaminants (Calmano, Hong, & Forstner, 1993). Therefore,

the buildup of potentially toxic metals carries a huge risk to the beneficial uses and

sustainability of the natural resources such as water, plants and aquatic animals.

Besides being the habitat for aquatic life, river is required in domestic, industrial and

agricultural applications. It is also one of the potable watersources in the world and a part of

an essential basicnecessity for healthy living. In Nigeria which has a population of about 170

million people, water pollution has been a great challenge as industrialization causes heavy

metals concentration to exceed the permissible limits. The concentration of heavy metals like

mercury, lead, cadmium, iron, cobalt, manganese, chromium, nickel, zinc, and copper often

exceed the maximum permissible limit recommended by standard organization of Nigeria and

World Health Organization. It is no longer safe for human consumption as it could lead to

various health impacts and mortality (Izah, Chakrabarty and Srivastav, 2016).

A study was conducted by Salem et al. (2000) on the relationship of heavy metals in

drinking water and their impact on human health. The drinking water samples were collected

from various areas from the Great Cairo Cities such as Heliopolice, El-Zaitoon, El-Mataria,

15

El-Salam, and El-Marg areas.The collected samples were from residential tap water of

patients who lived in these areas and diagnosed with renal failure, liver cirrhosis, hair loss,

and chronic anemia diseases. These samples were analyzed byusing ICP spectrometer (Perkin

Elmer ICP-400) and the method of Sam and Stanley 1963 was implemented to analyze urine

samples from all these patients to detect the possible presence of heavy metals in their urine.

The result of the study reveals that the contamination of drinking water supply to this

area is due to industrial wastes and agricultural activities. These anthropogenic activities

released hazardous and toxic materials in the groundwater thus contaminating the drinking

water supply. The study also shows that there are connections between the disease and the

contaminated drinking water. The disease of renal failure is related with drinking Pb- and Cd-

contaminated water supply, liver cirrhosis with Cu- and Mo-contaminated drinking water, hair

loss to Ni and Cr, and chronic anemia to Cu and Cd (Salem et al., 2000). Therefore, it is

proved that the presence of high level heavy metals in human drinks could threaten the health

of human being. Beside the above mentioned elements, there are several other harmful effects

caused by various heavy metals towards human’s health which are listed in Table 2.2.

Table 2.2: Harmful effects of several heavy metals on human health(Ali, et al., 2013)

Heavy metal Harmful effects

As As (as arsenate) is an analogue of phosphate and thus interferes with essential cellular processes such as oxidative phosphorylation and ATP synthesis

Cd Carcinogenic, mutagenic, and teratogenic; endocrine disruptor; interferes with calcium regulation in biological systems; causes renal failure and chronic anemia

Cr Causes hair loss

Cu Elevated levels have been found to cause brain and kidney damage, liver cirrhosis and chronic anemia, stomach and intestinal irritation

Hg

Anxiety, autoimmune diseases, depression, difficulty with balance, drowsiness, fatigue, hair loss, insomnia, irritability, memory loss, recurrent infections, restlessness, vision disturbances, tremors, temper outbursts, ulcers and damage to brain, kidney and lungs

Ni

Allergic dermatitis known as nickel itch; inhalation can cause cancer of the lungs, nose, and sinuses; cancers of the throat and stomach have also been attributed to its inhalation; hematotoxic, immunotoxic, neurotoxic, genotoxic, reproductive toxic, pulmonary toxic, nephrotoxic, and hepatotoxic; causes hair loss

16

Table 2.2 (continued): Harmful effects of several heavy metals on human health(Ali, et al.,

2013)

Heavy metal Harmful effects

Pb

Its poisoning causes problems in children such as impaired development, reduced intelligence, loss of shortterm memory, learning disabilities and coordination problems; causes renal failure; increased risk for development of cardiovascular disease.

Zn Over dosage can cause dizziness and fatigue.

Japan is one of the leading countries in industrialization and urbanization. During

1950s to1960s, Japan experienced a rapid economic growth and economic development

becomes the top priority. They hardly pay attention to environmental including water

resources. Industrial waste waterwas discharged into the river without proper treatment

resulting mercury contamination spread in the Minamata Bay. This irresponsible act resulted a

strange disease suffered by the community of Minamata. It was first found on a 7-year-old

little girl in late 1950s. She was diagnosed to suffer cerebral palsy at one private clinic, when

she was said to be malnourished by a municipal hospital pediatric department few days before

and diagnosed as infantile paralysis by another private clinic they visited five days before that.

The same mysterious symptoms were later suffered by several other patients in the

neighborhood and also to cats in this patients’ house. The cat started to be listless and curled

up. It staggers around in its cage a bit. Mild paralysis of the hind legs was observedwhen the

cat was allowed to walk outside. The cat’s symptoms progressed until one day, it ran around

in circles, gradually weakened, become completely listless, and lost all appetite. This

unknown disease with unknown cause was once called as “strange disease” back then and in

May 1956, it was called as “Minamata disease”. Now after 60 years of Minamata disease

outbreak, Japan still pay a high price on its economic growth and ignorance towards the

environment as there are still many patients suffering from the disease(Sugiyama, 2015).

Figure 2.3 shows on of the Minamata disease effect.

17

Figure 2.3: One of Minamata disease effect (Trust, 2010)

2.3 The Issues of River Contamination in Malaysia

Rivers in Malaysia have made immense contributions to the overall development of this

country. They have provided power generation, water for domestic, agricultural and industrial

consumption and have served as means of transportation and communication for the people.

Malaysia is gifted with rainfall and water resources. It is estimated that 566 billion m3 of

water running-off into the river system with an average rainfall of 3,000 mm each year

(Weng, 2005). In Malaysia, the major source of fresh water contributes some 97 per cent of

total water supply (Gasim, et al.,2009). The water is needed for drinking water supply,

sanitation, agriculture, industrialization, urbanization, fisheries, transportation, and recreation

and to produce hydroelectric power. The demand for water increases about 4% yearly and it is

estimated that about 20 billion per meter square (b/m3) of water is needed by the year

2020(Environment, 2005).

In Malaysia, like other countries in the world, the level of metal pollution in

freshwater bodies, especially the rivers, is no longer within safe limits for human

consumption. In year 2002, the Department of Environment (DOE) reported that industries

such as textile, metal finishing and electroplating, food and beverages, and animal feed could

not achieve more than 65% compliance. Some industries were operating either without

effluent treatment system (ETP) or with inefficient ETP. These industries had difficulties in

complying with parameters such as nickel, copper, lead, zinc and iron(Environment, 2002).As

a result, there is a gradual increase of heavy metal concentrations in sediment and water in

18

rivers which has reached alarming proportions. Statistics published by the Department Of

Environment for year 2004 revealed 8 per cent of our rivers to be polluted, 44 per cent

slightly polluted and the remaining 48 per cent to be clean (Kailasam, 2011). This indicates

that river basins in Malaysia are facing serious environmental problems.Figure 2.4 shows the

collection of Pahang River water sample to determine the level of bauxite.

Figure 2.4: The sample collection of Pahang River water for potential bauxite mining

pollution (Edward, 2016)

The trace metals in such waters may undergo rapid changes; affecting the rate of

uptake or release by sediments, thus influencing living organisms via the water sediment

chain. The levels of heavy metal concentration in river sediment in Malaysia have been

reported by other researchers. In the south region of Malaysia, the monitoring of heavy metal

concentration in Johor Strait (Danga Station and Pendas Station) has been polluted for

decades by chemicals or effluent from factories along the river. As observed through the years

of 1991, 2006, and 2009, the concentration of Zn in the Danga area was 31.428 ppm in 1991,

0.243 ppm in 2006 and 0.339 in 2009 while the concentration of Zn for the Pendas area were

16.092 ppm in 1991 to 0.753 ppm in 2009. The concentration of Cd in Danga Station ranged

from 0.0001 ppm in 2006 to 0.059 ppm in 1991 and up to 0.107 ppm in 2009. Pb

concentration for Danga Station in 2006 was 0.773 ppm, and 2.253 ppm in 2009, which

19

exceeded the required permissible level of 0.1 mg L−1 for Pb concentrations (Hadibarata, et

al., 2012).

It was also reported that the sediment inSkudai River, Johor Bahrucontains various

types of heavy metal such as As, Pb, Cr, Cu, Cd, Ni, Hg Sr, Y, Nb, Mo and Zn with the

concentration of most elements were in range of 1 ppm (parts per million) to 300 ppm

(Embong, 1998; Thanapalasingam, 2005). For the XRF analysis of Skudai River sediment,

the concentration of Zn, As and Pb have been found in the range of 210ppm -310 ppm, 10

ppm -40 ppm and 20 ppm- 50 ppm respectively (Embong, 1998). Meanwhile, in the east coast

region of Malaysia, it was reported that there were about 31elements (Al, Fe, K, Na, Mg, Ca,

Mn, Ba, Cr, Zr, Ni, Sr, Zn, Y, Li, Cu, Mo, Nb, Th, Co, Ga, W, Ta, Be, Ti, Ge, Se, Bi, Te, Sc

and Re) in Terengganu River basin which ranges from 0.05 μg/kg to 40.01 mg/kg(Sultan &

Shazili, 2010).

2.4 Remediation Techniques on Heavy Metals-Contaminated Soil and Sediment

Heavy metal contaminated sites are unusable resources until it is restored to a safer level. As

the concentrations of heavy metals in the environment increase rapidly from year to year,

cleaning them up from the contaminated soil is very crucial in order to detract their impact on

the ecosystems. The sites could be restored for beneficial practice with sufficient site

remediation planning and proper management of remediation technologies.Remediation of

soil contamination can be achieved by(Yeung, 2009b):

a) In-situ removal of contaminants from the contaminated site for further off-site

treatment of the contaminants removed

b) Ex-situ removal of contaminants from the contaminated soil after the soil has been

excavated from the contaminated site

c) In-situcontainment of the contaminants with the toxicity of the contaminants remains

unchanged but the contaminants are isolated from human contacts for a predetermined

period of time

d) Excavation of the contaminated soil and transport it to an engineered containment

system for long-term isolation

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e) In-situtransformation of the contaminants so that the mobility and/or the toxicity of the

contaminants are significantly reduced so as to reduce the risk of soil contamination to

public health and the environment

f) Any combinations of these remediation mechanisms.

There are various methods such as amendments, washing, sand cap, flotation, ultrasonic-

assisted extraction, electrochemical remediation, phytoremediation and many more were

employed on the contaminated sites with the aim of remediating the contaminated soil and

sediment. Remediation is not only implemented to restore the soil and sediment for beneficial

use only, but it is also done to reduce its potential harmful effects towards living organisms.

The descriptions of some remediation techniques are discussed as follow:

2.4.1 Amendment

Amendment is one of the remediation techniques applicable on contaminated soil and

sediment. It could possess high cation exchange capacity (CEC), lower metal mobility and

bioavailability in sediment by precipitation or sorption, and decreasing their solubility.

Minerals like apatite, zeolites, steel shot, or beringiteare inexpensive amendment

andfrequently used during in situ metal immobilization.Compared to the amendments used in

soil, the one that was used in sediment usually has higher sorption capacity, lower water

solubility, higher stability under reducing and oxidizing conditions and lower cost (Peng et

al., 2008).

Amendment technique on sediment remediation is usually using apatite. It usually

formulated in the form of Ca10–a−bNaaMgb(PO4)6−x(CO3)xF2+0.4x with isomorphic substitution

of carbonate for phosphate, F for hydroxy, and minor substitution of Ca2+ by Na+ and

Mg2+atoms(Peng et al., 2008). During the remediation process, metal are incorporated with

Ca2+ in the lattice through ion exchange. Phosphate iscorrespondingly released as apatite are

dissolute in the reaction and forming a new metal-phosphate solid phase (such as

Ca10−xPbx(PO4)6(OH)2). Through this process, apatite minerals are able to mobilize almost

all Pb, Mn, Co, Cu, Cd, Zn, Mg, Ba, U, and Th in sediment (Peng et al., 2008).

21

2.4.2 Sandcap

Sand cap is a remediation technique which utilizes sandy material such as clean sediment,

sand or gravel as a capping in order to decrease the direct contact area between the

contaminated sediments with water. With this technique, the mobile and the exchangeable

metals are transformed from the contaminated sediment into the clean cap and combined with

particles in more stable forms. The heavy metal concentration in water could be reduce for up

to 80% by placing the coarse-grained cap, provided if the thickness is approximately 50 cm

(Peng et al., 2008).

This inexpensive method is a good selection for contaminated sediment remediation to

reduce transfer rate of metal in sediment but has a small immobilization effect of heavy metal.

Thus, this method is usually coupled or assisted with some other kind of remediation

technique such as amendment (such as apatite, rock phosphate, lime or zeolite) to enhance its

effectiveness(Peng et al., 2008).Figure 2.5 shows the work of sand cap remediation technique.

Figure 2.5: The work of sand cap remediation technique (J. F. Brennan Co. Inc.

2013)

2.4.3 Washing

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A simple ex situ of sediment washing remediation technique involves adding washing water

to the dredged sediment and heavy metals are transferred to the wash solution. This method is

usually applied on sands, gravels, or weaker bound metals in the form of exchangeable,

hydroxides, carbonates and reducible oxides fraction. Several additives such as acid washing

(e.g. H2SO4 and HNO3), chelating agents (e.g. EDTA, DTPA and EDDS) or surfactants (e.g.

rhamnolipid) are utilized in order to improve the performance of sediment washing (Peng et

al., 2008).

As for soil washing, it could be used as a pretreatment process to reduce the volume

of feedstock for other remediation technology. Initially, the excavated soil was mechanically

screened to remove various oversize materials, and separated to generate coarse- and fine-

grained fractions of the contaminated soil. The separated soil was then treated by individual

fractions, i.e. soil washing and management of the residual generated. The extracting fluid

requires further treatment afterwards to remove and destroy the contaminants (Yeung,

2009b).Figure 2.6 shows a typical process diagram of soil washing remediation technique.

Figure 2.6: Typical process diagram of soil washing remediation technique (HBR

Limited, 2013)

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Some remediation technology such as soil washing requires the usage of chemical

solutions in decontaminating the polluted area. In watertight or low permeable soil area, the

possibility of insufficient reagent penetration through the soil has become the major limitation

of this remediation process. For some other processes such as stabilization, solidification and

vitrification, the texture and property of soil mass may change due to the extreme or intense

treatment implemented. The post treatment soils are sometime unfit for agriculture or natural

preserve purpose.

Besides removing or decontaminating pollutant from the soil, there are treatments that

choose to only stabilize the heavy metal in its particular area such as stabilization and

solidification, bioremediation and vitrification. However, this kind of remediation technique

has a potential of heavy metal mobility in future (Cameselle, Chirakkara, & Reddy, 2013).

Every remediation technology requires much energy usage besides its long term application

and high cost demand. Among all these frequently applied methods, phytoremediation

emerges to be a great green solution to the problems of heavy metals contamination in soil,

rivers and sediments due to its low expenses and suit to be applied in large scale of in situ

application.

2.5 Phytoremediation

The term “phytoremediation” is a combination of two words; a Greek word “phyto” means

“plant” and a Latin word “remedium” means “to correct or remove an evil” (Ali, et al., 2013).

Phytoremediation is the use of living green plants for in situ risk reduction and/or removal of

contaminants from contaminated soil, water, sediments, and air. Phytoremediation can be

defined as destruction, inactivation, or immobilization of pollutant in an undamaging form,

which is primarily mediated by photosynthetic plants (Terry & Banuelos, 2000). Specially

selected or engineered plants are employed in the process. Plants that suit to hold the role of a

phytoremediator should possess the ability to accumulate the target metal(s) in its above-

ground parts (shoots) and able to withstand the concentration of metal accumulated in its

tissues. In addition to that, a fast growth plant with highly effective (i.e. metal accumulating)

biomass and easily harvestable would also an ideal candidate for the phytoremediation

process (Kärenlampi, et al., 2000).

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2.5.1 Techniques of phytoremediation

Fundamental and applied research has unambiguously validated that selected plant species

own the genetic potential to remove, degrade, metabolize, or immobilize a wide range of

contaminants by different process based on the nature of their remediation process known as

phytoextraction, rhizofiltration, pythostabilisation, phytovolatilization, phytodegradationand

phytodesalination(Anjum, et al., 2013; Raskin & Ensley, 2000). Each technique demonstrates

different ways a plant could be utilized to remediate contaminant from its sources. Figure 2.7

illustrates the techniques of phytoremediation process.

Figure 2.7: Techniques of phytoremediation process(Cameselle et al., 2013)

The descriptions of each technique are summarized in Table 2.3. In this research, the

focus will be given to phytoextraction which is the use of metal-accumulating plants that can

transport, translocate and concentrate metals from the contaminated soil to the roots and

aboveground shoots (Raskin & Ensley, 2000; Terry & Banuelos, 2000). This remediation

technique is implemented to recover metals from contaminated soils using inedible crops

(Anjum, et al., 2013). A plant that is unattractive to animal is suitable for phytoextraction in

order to minimize the potential risk of transferring the metals to the higher trophic level of

terrestrial food chain. Most importantly, the plant used for phytoextraction should have high

metal tolerance and able to accumulate metal in a large amount (Thangavel & Subbhuraam,