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

10

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

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Buell, P. and Girad, J., 1994. Chemistry: An Environmental Perspective. Prentice Hall, United States of America.

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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.

Considine, D.M., 1995. Van Nostrand s Scientific Encyclopedia. 8th Ed. Thomson Publishing, United States of America, 2066-2068.

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Dunnick, J.K and Fowler, B.A., 1988. Cadmium. In: Seiler, HG., and Siegel, H. (editor) Handbook on Toxicity of InorganiC Compounds. Marcel Dekker Inc., New York.

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Friberg, L., Nordberg, o.F., and Vouk., 1979. Handbook on the Toxicology of Metal. Elsevier or North-Holland Biomedical Press, Netherland, 1-378 pg.

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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,

Harrison, RM. and Laxen, D.P.H., 1984. Lead Pollution: Cause and Control. Chapman and Hall, New York.

Harvey, D., 2000. Modem Analytical Chemistry. McGraw Hill, New York

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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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Jennet, lC., EIDer, S.W. and Wixson, B.G., 1980. Mobilazation and Toxicology a Species of Sedimentary Contamination. In: Beaker, RA (editor). Contamination and Sediments 1: Fate and Transport Care Studies, Modelling, Toxicity. Ann Arbor Science Publisher Inc., Orichigan. 429-444.

John, G., 1984. Analysis of Food Contaminants. Elsevier Applied Science Publishers, New York.

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Louis, W.C., 1996. An Introduction to Neurotoxicology of Metal. In: Louis, W.C., Lazlo, M., and Tsuguyoshi, S. (editor) Toxicology of Metal. Lewis Publisher, New York, 509-511.

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