DETERMINATION OF CADMIUM, LEAD AND NICKEL AMOUNT IN
PICKLED VEGETABLES
SAFNIBTJIMAT
ffRPUSTAKAA" UNIVERSITI MAlAYSIA SA8A"
THIS DISSERTATION IS SUBMITTED AS PARTIAL FULFILMENT OF
THE REQUIREMENTS FOR THE AWARDING OF BACHERLOR OF
SCIENCE WITH HONOURS
INDUSTRIAL CHEMISTRY PROGRAMME
SCHOOL OF SCIENCE AND TECHNOLOGY
UNIVERSITI MALAYSIA SABAH
2008
PUMS99:1
UNIVERSITI MALAYSIA SABAH
BORANG PENGESAHAN STATUS TESIS@
JUDUL: 061v.""ir)(,·U()r) ,,( 'Yl<IIT'iulY', le'oO Of'd r" ... ke-/ nlY'~~lI,...t I,.. I-~i:~kd
V~~.bltS
SA Y A S.6.~N IS' .::r T"'lA-t (HURUF BESAR)
SESI PENGAJIAN: toTO/'C. - <. "f / (~ I
mengaku membenarkan tesis (LPSMlSarjana/Doktor Falsafah) ini disimpan di Perpustakaan Universiti Malaysia Sabah dengan syarat-syarat kegunaan seperti berikut:- .
1. Tesis adalah hakmilik Universiti Malaysia Sabah. 2. Perpustakaan Universiti Malaysia Sabah dibenarkan membuat salinan untuk tujuan pengajian
sahaja. 3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institutsi
pengajian tinggi. 4. Sila tandakan (I)
D D
SULIT
TERHAD
(Mengandungi maklumat yang berdarjah keselamatan atau Kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972)
(Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasilbadan di mana penyelidikan dijalankan)
1
Disahkan Oleh NURULAIN 811 TIISMAIL IZ( TIDAl( TERHAD
~it~> ~ LlBRARAN
lINIVEBSITI MAL YSIA SABAH (T NDATANGAN USTAKAWAN) I (T A~P.A1ANGAN PENULlS) --
Alamat Tetap:~i.DEOS'~ ~F.l !'~6. -:r ~"'1Al\; ~t J$.6.,
------.------~----------S3CJIC (+~c'-G 1(l:.;!."'A !(.6.'-~ Nama Penyelia
Tarikh:_._ ._
CAT ATAN:- ·Potong yang tidak berkenaan. ··lika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa
/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT dan TERHAD.
@Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan atau disertai bagi pengajian secara kerja kursus dan Laporan Projek Sarjana Muda (LPSM).
i i !
TI
DECLARA TION
Hereby, I admit that this dissertation is original except for quotations, excerpts,
summaries and references, which have been duly acknowledged.
May, 2008
SAFNIJIMAT
HS200S-1229
m
VERI FICA TION
Name : Safni bt Jimat
Title : Determination of cadmium, lead and nickel amount in pickled vegetables
( D azmal Effendi Arshad )
( Prof. Madya Dr Martus Jo~ony ) ~.
( Supt. (K) Prof Madya Dr SharifT A.K Omang )
May, 2008
iv
ACKNOWLEDGEMENT
Alhamdulillah, thanks Allah finally my final project is finish. First and foremost, I
would like to thank to my supervisor, Dr Sazmal Effendi Arshad for all his advices,
times and guidance in helping me to accomplish this dissertation. I also would like to
thank to Prof Madya Dr Marcus Jopony as our final project coordinator with all his
suggestions and comments all along to finish this dissertation.
Besides that, I would like to thank to all lab assistance, En Sani, En Yusri, and
En Samudi for their help, in apparatus and chemical preparation, and also
instrumentation usage as well. To all my friends and coursemates who be so
understanding, sharing information and helping me in solving problem.
Last but not least, to my beloved mom. Thanks for all your supports. And to all
party that have been helping me directly or indirectly in process to complete my
dissertation.
v
ABSTRACT
This study is carried out to detennine the concentration of lead, cadmium and nickel in
pickled vegetables. Pickled Chinese mustard plant, pickled cabbage and pickled lettuce
have been choose for this study. Samples are collected from local market around Kota
Kinabalu. Two sample preparation methods are used in these studies which are dry ashing
method and wet digestion method. Finally, these samples are analyzed by using Flame
Atomic Absorption Spectroscopy (FAAS). The amount of lead and cadmium are higher
in sample prepared by wet digestion method. While the amount of nickel are higher in
sample prepared by dry ashing method. Pickled cabbage have higher amount for all metal
which are averagely 2.37 Ilg!g for cadmium, 20.54 Ilg/g for lead and 23.4 Ilg/g for nickel.
Whereas, pickled lettuce have the lowest amount for all metal which are averagely 0.72
Ilg/g for cadmium, 2.54 Ilg/g for lead and 7.45 Ilg/g for nickel. For pickled chinese
mustard plant, the amount of cadmium is averagely 2.11 Ilg!g, 14.07 Ilg/g for lead and
19.30 Ilg/g for cadmium.
vi
ABSTRAK
Kajian ini menjurus kepada penentuan kandungan logam plumbum, kadmium dan
nikel dalam sayuran jeruk. Tiga sampel sayur jeruk yang di pilih adalah sawi jeruk,
kubis jeruk dan salad jeruk. Semua sampel ini diperolehi daripada pasar dan kedai di
sekitar Kota Kinabalu. Dua kaedah penyediaan sampel digunakan dalam kajian in~
iaitu kaedah penghadaman basah dan pengabuan kering. Sampel kemudiaannya akan
di analisa menggunakan spektrokopi serapan atom nyalaan (F AAS). Kandungan
logam cadmium dan plumbum dalam sampel adalah lebih tinggi melalui penyediaan
sampel kaedah penghadaman basah. Manakala kandungan logam nikel dalam sam pel
adalah lebih tinggi menerusi kaedah penyedian sampel pengabuan kering. Kubis jeruk
mencatatkan kandungan logam nikel paling tinggi iaitu purata 23.4 Ilglg. Begitu juga
dengan kandungan logam plumbum iaitu purata 20.54 Ilg/g dan logam cadmium iaitu
purata 2.37 Ilg!g. Manakala salad jeruk mencatatkan kandungan logam paling rendah
iaitu purata 7.45 Ilg!g untuk logam nikel, purata 2.54 J.1g1g untuk logam plumbum dan
purata 0.72 Ilglg untuk logam cadmium. Untuk sawi jeruk pula kandungan logam
nikel ialah purata 19.30 11 gig, purata kandungan logam plumbum 14.07 Ilg!g dan
purata 2.11 Ilg!g bagi logam cadmium.
UMS UNIVERSITI MALAYSIA SABAH
TABLES OF CONTENT
TITLE
DECLARATION
VERIFICATION
ACKNOWLEDGEMENT
ABSTRACT
ABSTRAK.
TABLES OF CONTENT
LIST OF TABLE
LIST OF FIGURE
LIST OF SYMBOL
LIST OF FORMULA
LIST OF APPENDIX
CHAPTER 1 INTRODUCfION
1.1 Introduction
1.2 Objective
1.3 Scope of study
CHAPTER 2 LITERATURE REVIEW
2.1 Metal
2.1.1 What is Metal?
2.l.2 Metal in Food
2.1.3 Toxicity
2.2 Metal as Mineral and Toxic Metal
2.2.1 Lead
2.2.2 Cadmium
2.2.3 Nickel
2.3 Pickled Vegetables
2.3.1 The Processes of Pickled Vegetables
vfi
Pages
ii
iii
iv
v
vi
VlI
IX
X
XI
xii
xiii
1
1
3
4
5
5
5
7
9
10
12
14
17
19
® 1JSlII~~IA~
2.3.2 The Importance of Pickled Vegetables
2.4 Atomic Absorption Spectroscopy (AAS)
2.4.1 FAAS in Food Analysis
CHAPTER 3 METHODOLOGY
3.1 Sample
3.2 Apparatus and Chemical Preparation
3.3 Sample Preparations
3.3.1 Dry Ashing Method
3.3.2 Wet Digestion Method
3.4 Instrumentation
3.5 Standard Solution Preparation
3.5.1 Lead Standard Solution
3.5.2 Cadmium Standard Solution
3.5.3 Nickel Standard Solution
3.6 Calibration Graph
3.7 Data Interpretation
CHAPTER 4 RESULTS AND DISCUSSION
Change of Colour Before and After Digestion
viii
22
24
25
27
27
28
29
29
30
31
32
33
33
33
34
34
35
35 4.1
4.2
4.3
Heavy Metal Concentration 36
Determination of Heavy Metal Concentration Based on Data Interpretation 36
4.4.1 Cadmium 36
4.4.2 Lead 39
4.4.3 Nickel
4.4 Comparison Between Dry Ashing and Wet Digestion Method
CHAPTER 5 CONCLUSION
REFERENCES
APPENDIX
41
43
48
49
54
Table 2.1
Table 3.1
Table 4.1
LIST OF TABLE
Example of heavy metal usage
Parameters used for AAS instrument
The colour change in sample during the analysis
ix
Page
6
31
34
x
LIST OF FIGURE
Page
Figure 3.1 Pickled chinese mustard plant 27
Figure 3.2 Pickled cabbage 28
Figure 3.3 Pickled lettuce 28
Figure 3.4 Apparatus use in this study 29
Figure 4.1 Cd amount (~glg) in sample by wet digestion method 36
Figure 4.2 Cd amount (~g/g) in sample by dry ashing method 36
Figure 4.3 Lead amount (~g/g) in sample by wet digestion method 38
Figure 4.4 Lead amount (I.lg/g) in sample by dry ashing method 39
Figure 4.5 Ni amount (I.lglg) in sample by wet digestion method 40
Figure 4.6 Ni amount (I.lg/g) in sample by dry ashing method 41
Figure 4.7 Comparison of heavy metal concentration in pickled cabbage
between wet digestion and dry ashing method 43
Figure 4.8 Comparison of heavy metal concentration in pickled
chinese mustard plant between wet digestion and
dry ashing method 44
Figure 4.9 Comparison of heavy metal concentration in pickled lettuce
between wet digestion and dry ashing method 45
xi
LIST OF SYMBOL
FAAS Flame Atomic Absorption Spectroscopy
Pb lead
Cd cadmium
Ni nickel
HCI hydrochloric acid
HCI04 perchloric acid
HN03 nitric acid
°C degree Celsius
kg kilogram
g gram
~g/g microgram per gram
~m micrometer
~g!L microgram per liter
~L microliter
L liter
ppm part per million
WHO World Health Organization
% percentage
Formula 3.1
Formula 3.2
LIST OF FORMULA
Standard solutions preparations
Data interpretation
Page
32
34
xii
xiii
LIST OF APPENDIX
Page
Appendix A Tables of results for wet digestion method 54
Appendix B Tables of results for dry ashing method 55
Appendix C Calibration graph for lead 56
Appendix D Calibration graph for cadmium 57
Appendix E Calibration graph for nickel 58
Appendix F Pictures of furnace 59
Appendix G Pictures of Flame Atomic Absorption Spectroscopy 60
Appendix H Pictures of samples during wet digestion process 61
Appendix I Pictures of samples from dry ashing method 62
Appendix J Pictures of samples from wet digestion method 63
UMS UNIVERSITI MALAYSIA SABAH
CHAPTER 1
INTRODUCTION
1.1 Introduction
Fermented foods are food substrates that are invaded or overgrown by edible
microorganisms whose enzymes, particularly amylases, proteases, lipases hydrolyze
the polysaccharides, proteins and lipids to nontoxic products with flavours, aromas
and textures pleasant and attractive to the human consumer. If the products of enzyme
activities have unpleasant odours or undesirable, unattractive flavours or the products
are toxic or disease producing, the foods are described as spoiled (Steinkraus, 1997).
Fermented vegetables can bring many benefits to people in developing
countries. Fermented foods play an important role in providing food security,
enhancing livelihoods and improving the nutrition and social well being of millions of
people around the worlds.
(!)UMS . ~ UNIVERSITI MALAYSIA SABAH
2
There are several options for preserving vegetables including drying, freezing,
canning and pickling. Vegetables can become crisp, tangy, sweet and sour with the
process pickling. The flavour changes easily by varying the amount of vinegar, salt,
sugar or seasonings.
Pickled products have definite geographical or regional preferences Pickling is
one of the oldest forms of food preservation. It has been traced back to the dawn of
civilization, 4500 years ago when people learned to preserve cucumbers by pickling
them in salty brine (Steinkraus, 1997).
While fermented foods are themselves generally safe, it should be noted that
fermented foods by themselves do not solve the problems of contaminated drinking
water, environments heavily contaminated with human waste, improper personal
hygiene in food handlers, flies carrying disease organisms, unfermented foods
carrying food poisoning or human pathogens and unfermented foods, even when
cooked if handled or stored improperly. Also improperly fermented foods can be
unsafe (Steinkraus, 1997).
Food pollution are caused by heavy metal pollution which they can exist
naturally and also through anthropogenic. The toxicity of the metal can be seen in
some issues. As example is Couch-couch Disease that happen in Japan at 1960. It was
caused by the watering systems that are polluted with cadmium (Suriah, 1993). Other
than that, there are some of the metal that exists as macromineral and micromineral in
this world. They have their own uses and toxicity towards the humanity.
UMS UNIVERSITI MALAYSIA SABAH
3
Nowadays, the anxiety towards the metal pollution has grown up because of
the dangerous of toxic metal and other chemical substances that can affect human
health and the environment. Heavy metals are known as the most dangerous pollutant.
When it comes to environment, it is hardly to destroy and removed, especially when it
has been adsorbed by soil. It will be accumulate by time. Then it enters into the
biosphere or food chain and further will affect human health (Xing and Chen, 2000).
In this study, Atomic Absorption Spectroscopy (AAS) are used to determine
the metal concentration in the sample. AAS is the most simple, sensitivity, fast and
precise method in metal analysis (Howerde, 1999). AAS is an analytical method for
the determination of elements, based upon the absorption of radiation by free atoms.
Between all of absorption spectroscopy method, Flame Atomic Absorption
Method (F AAS) is used in this study. F AAS have detection limit higher than Graphite
Furnace Atomic Absorption Spectroscopy (GF AAS), thus it is usually used to detect
higher analyte concentration in the sample (Harvey, 2000). GF AAS allows
determination of a wider range of elements and easily extends into the J.lg/kg range of
concentration.
1.2 Objectives
a) To determine the amount oflead, cadmium and nickel in pickled vegetables.
b) To compare between dry ashing method and wet digestion in determination of
lead, cadmium and nickel in pickled vegetables. UMS UNIVERSITI MALAYSIA SABAH
4
c) To compare the amount of lead, cadmium and nickel between three sample
(Chinese mustard plant pickled, cabbage pickled and lettuce pickled).
1.3 Scope of Study
Major scope in this study in to determine the amount of lead, nickel and cadmium in
three samples that has been choose which are Chinese mustard plant, cabbage and
lettuce pickled. The amount of metal in this sample maybe different due to the process
and also the origin of the vegetables before it are made to pickled.
Samples are focus to the solid part of the samples which means the vegetables
leaves. This is because, consumer eat the vegetables leaves. So, that is where human
get metal inside their body through their eating. The liquid parts in the pickled which
contain vinegar are just used to ferment the vegetables.
This study use F AAS as instrument to detect the concentration level in the
pickled sample. Besides th~t, this study also differentiates two sample preparation
methods, dry ashing and wet digestion. These two sample preparation methods are
widely used in the detennination process of heavy metal in food. So this study will
determine which sample preparation methods are more suitable for detection of lead,
cadmium and nickel in food especially in vegetables.
CHAPTER 2
LITERATURE REVIEW
2.1 Metal
2.1.1 What is Metal?
Metal is the element that can form cation and ionic bonding. It can be differentiate
through its ionization characteristics and also the bond with metalloid and non-metal
element. In the periodic table, metals are separated by nonmetal element and half
metal element. The major characteristics of metal are they have high density, ductile,
high boiling point, hard and also good heat and electric conductor.
Metals can be categorized into transition metal and heavy metal. The origin
existences of heavy metal are through the geological process such as weathering,
erosion and adsorption (Ahmad Badri, 1987). The heavy metals usually have their
toxic effect towards organisms for example, lead, cadmium, aluminium s UNIVERSITI MALAYSIA SABAH
6
other heavy metals. Most of these metal elements give benefits to organisms in low
quantity but in the higher concentration, it will present as toxic (Murugadas, 1997).
Heavy metals can be categorized as the metals elements that have density more
than 5 glm3 (Anond, 1990). Heavy metal in the periodic table is include 38 elements
which elements with atomic number start from 22 to 34 (Titanium until Selenium), 40
to 52 (Zirkonium until Tellerium) and 72 to 83 (Hafnium until Bistmuth) (Jennet et
a/.,1980).
One of the special ability of metals is that they are different from other organic
element. They will not be destroyed in the environment and can be transferred from
one environment to another (Micheal, 2004).
Recently, heavy metal has been used in various sectors as industrial,
agriculture, development, transportation, food and others. The examples of heavy
metal used are listed in the Table 2.1.
Table 2.1 Examples of heavy metal usage (Manahan, 1994).
Cadmium metal plated, alloy, machinery equipment, pigment in paint, glass,
enema, textile
Lead battery storage, pigment, gasoline additive, weapons
Nickel alloy, coins, battery storage, catalyst s
7
2.1.2 Metal in Foods
Human and animal cannot live and grow without metal existence in their body. It is
found that 21 types of metal are the micromineral metal or called as micronutrient
which are necessary in food such as ferum, copper, manganese and zinc (Crause and
Mohan, 1978).
Based on Food Act 1983 and Food Rules and Regulation 2000, food pollution
is categorized as any foreign elements, dangerous toxic that contains or exist in food
including metal pollution, microorganisms, pesticide waste not including seasoning,
food stabilizer or other substance that are permitted in food.
In general, the heavy metal pollution happens in the environment. The
environment is where the food is come from. The place where the foods come can
influenced the metal content in it. This pollution is caused by the natural factor and
anthropogenic factor (Novothy, 1995). This is, of course a reflection of environmental
variations, particularly with relation to soil composition.
These pollution aspects have been discussed by mass media recently especially
about chemical and additive in food issues. The presence of these heavy metal in food
are one of the case that are worried the society because it can affect the human health.
It is known that serious systemic health problems can develop as a result of xc s I e S UNIVERSITI MAlAYSIA SABAH
8
accumulation of dietary heavy metals such as cadmium, chromium and lead in the
human body (Sharma el al., 2005).
The problem of metal contaminations during food processing occurs
frequently as a result of misuse of equipment or the overlooking of the consequences
of using unsuitable metals in apparently insignificantly ways. Moreover, metal
contamination in food is also from polluted environment. As example, vegetables
absorb heavy metals from soil as well as from surface deposits on the parts of
vegetables exposed to polluted air. Moreover, the presence of heavy metals in
fertilizers contributes an additional source of metal pollution for vegetables (Yusuf et
aI., 2002).
Furthermore, food processing equipments and containers have long been
recognised as sources of chemical as well as microbiological contamination of food. It
is said that the Romans suffered from chronic poisoning by lead leached from the
glazed pottery vessel that they used to store wine. In more modern times, the use of
similar vessels to hold pickled olives has resulted in lead poisoning in Yugoslavia
(Conor, 1991).
Besides lead, cadmium and nickel also can poisoned food from the food
processing equipment. Cadmium which is often used in engineering to plate small
pieces of equipment is readily soluble in weak acid solutions. If ~s uu1\!l S UNIVERSITI MALAYSIA SABAH
9
processing plants should be confined to parts which do not come directly into contact
with food. Unfortunately, cadmium-plated vessels have been used improperly on
occasion and cause poisoning of foodstuff Nickel also is a useful plating metal and
which. can be dissolved if it comes into contact with food. Nickel is not considered to
be a toxic metal, but it is very effective catalyst. It can cause oxidative spoilage and
rancidity in fat-containing foods. Scraped-surface heat exchangers are often nickel~
coated. If they are moved in a food plant for a different duty from what they were
designed for originally, corrosion can occur which resulting in contamination food
products (Conor, 1991).
Metal existence in food can cause a variety of colour changes in food during
cooking and storage. The flavour of a food product can also be adversely affected by
the presence of a metal contaminant. For example is from the can corrosion. Corrosion
product of steel, especially iron salts will cause loss of odour as well as development
of a stringer, metallic or bitter taste.
2.1.3 Toxicity
The reaction between chemical substances the biological system usually is caused of
metal toxicity. And then the biological system will caused the chemical reaction to
take place (Louis, 1996).
UMS UNIVERSITI MALAYSIA SABAH
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Metals are toxic because it has ability form bond with membrane, and
indirectly it will affect the membrane function. Consequently, the electron, sugars and
other substance transportation across the membranes will be disturbed. The effect of
the metal toxicity also will cause alteration of substance and elements in the
membrane. (Ernest, 1996).
Some of the metals are extremely toxic and can lead to dangerous diseases.
Lead and cadmium are heavily toxic element. Ferum, zinc, nickel, selenium and others
micronutrient are metal that are need in human body for growth but it will become
dangerous if the quantity are too high.
2.2 Metal as Mineral and Toxic Metal
To maintain living and health, all physiology activity has to be process and operate in
their actual way. If not, any disturbance in metabolism activities can cause pain and
death. This activity need specific control agent. Besides hormones and its "special
assistance" as a connector to cell enzyme, micronutrien as vitamin and mineral are
also need to play an important role in the metabolism activities.
Among the metals found in the human body, only a small number are believed
to be essential for normal life. Most of the metals present are artefact, with no
UMS UNIVERSITI MALAYSIA SABAH
REFERENCES
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Concon, 1M., 1988. Food TOXicology: Principles and concepts (part B). Marcel Dekker, New York.
Conor, R, 1991. Metal contamination of food. 2nd Ed. Elsevier science Publishers Ltd., New York.
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Hansen, lC., 1988. Exposure to Heavy Metals (Hg, Se, Cd & Pb) in Greenlanders: A Review of an Arctic Environmental Study. Doctoral Thesis. University of Aarhus, Department of Environmental and Occupational Medicine,
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Howerde, E.S., 1999. Laboratory Test For the Assessment of Nutritional Status. 2nd Ed. Boca Raton, London.
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