investigation the heavy metal contents in surface water and sediment collected in thadluang marsh

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VIETNAM NATIONAL UNIVERSITY, HANOI
VNU UNIVERSITY OF SCIENCE


PHETDALAPHONE BOUTTAVONG


INVESTIGATION THE HEAVY
METAL CONTENTS IN SURFACE WATER AND
SEDIMENT COLLECTED IN THADLUANG
MARSH (LAO PDR)



MASTER THESIS






HANOI, 2011


Phetdalaphone BOUTTAVONG

2009-2011



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VIETNAM NATIONAL UNIVERSITY, HANOI
VNU UNIVERSITY OF SCIENCE


PHETDALAPHONE BOUTTAVONG

INVESTIGATION THE HEAVY METAL
CONTENTS IN SURFACE WATER AND SEDIMENT
COLLECTED IN THADLUANG
MARSH (LAO PDR)


MASTER THESIS


Supervisor: Assoc. Prof. PhD. Ta Thi Thao





HANOI, 2011
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Abstract
In Vientiane, water and sanitation management in the urban area is experiencing
stagnant pollution. Unsanitary conditions and threat of seasonal pollution in selected
spots is likely to occur and increase with the growing urban population. The
sanitation system entails an on-site disposal of human waste without introduction of
full water-borne sewerage with treatment facility and safe disposal arrangement. The
majorities of households relies on water flush latrines and are connected to a pit or
chamber for containment of excreta. However, due to the low permeability of the soil
and the high groundwater table around Vientiane, many soak-a-ways fail to operate
effectively resulting in discharge of sewage from tanks into drainage channels or low
lying areas. This pollution leads to effluent overflows, environmental degradation
and health hazards.
For the sake of assessment in what extent is water polluted, an analytical method
with high sensitivity and the capability and providing a good accuracy and precision
should be used. Atomic absorption spectroscopy (AAS) is a spectroanalytical
procedure for the qualitative and quantitative determination of chemical elements
employing the absorption of optical radiation (light) by free atoms in the gaseous
state. In analytical chemistry the technique is used for determining the concentration
of a particular element (the analyte) in a sample to be analyzed. The technique makes
use of absorption spectrometry to assess the concentration of an analyte in a sample.
My study focuses on heavy metals content in surface water and sediment collected in
ThadLuang Marsh in Vientiane Capital City. Providing an overview about
alarmingly polluted situation, this research based on determination of Copper, Lead,

Cadmium and Zinc by Flame – Atomic absorption spectroscopy.






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Acknowledgements

I would like to thank, DAAD, Deutscher Akademischer Austauschdienst (German
Academic Exchange Service) and Technich University Dresden for providing the
scholarship of the Master’s program. My sincere thanks also due to the Dean of
faculty Environmental of sciences in National University of Lao P.D.R for the kind
permission offered me to study.
Thank Assoc. Prof. Dr. Ta Thi Thao - my supervisors for encouragement,
constructive guidance's
I would like to express the profound gratitude and the great appreciation to my
advisor Prof. Bernd Bilitewski for his excellent guidance, excellent encouragement
and valuable suggestions throughout this study. Special appreciation is extended to
Prof. Dr. Nguyen Thi Diem Trang and Prof. Dr. Do Quang Trung committee
members for their valuable recommendation and dedicated the valuable time to

evaluate my work and my study during being in Vietnam.
During studying in Hanoi University of Science, I felt very lucky, it give me the
opportunity to have lots of good friends, good memories, so I would like to say
thanks and pleasure to meet all of you. Even though we came from different
countries, we can make friend together. I hope and wish that I would work together
and meet each other again in some conferment.
Finally I would like to express deep appreciation to my lovely family and relatives
for their love, kind support, and encouragement for the success of this study. This
thesis is dedicated for you.





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Contents
List of Figures 7
List of Tables 8
List of Abbreviations 9
INTRODUCTION 10
CHAPTER 1: OVERVIEW OF WATER AND SEDIMENT POLLUTION IN
THADLUANG MARSH 10
1.1. Topography of ThadLuang marsh 13

1.2. Present status of water and sediment pollution in ThadLuang marsh 14
1.3. Toxicity of Cadmium Cd, Copper Cu, Lead Pb, Zinc Zn 16
1.3.1. Cadmium Cd 16
1.3.2. Copper Cu 17
1.3.3. Lead Pb 18
1.3.4. Zinc Zn 20
1.4. Analytical methods for determination of heavy metals in water and sediment
samples 22
1.4.1. Electrochemical methods 22
1.4.2. Spectrophotometric methods 24
CHAPTER 2: EXPERIMENTS 28
2.1. Research Objects and research contents 28
2.1.1. Research objects 28
2.1.2. Research contents 28
2.2. Chemicals and Apparatus 29
2.2.1. Chemicals 29
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2.2.2. Apparatus 29
2.2.3. Equipments 30
2.3 Sampling and Sample Preparation 30
2.3.1. Study Area 30
2.3.2. Sampling and sample preparation 35
2.3.3. Sediment samples 35
2.4. Analytical methods for determination of Cu, Pb, Cd, Zn 36
2.4.1. Flame atomic absorption spectroscopy method (F-AAS): determination of

heavy metal content in sediment samples 36
2.4.2. Inductive couple plasma – mass spectrophotometry (ICP-Ms) for the
determination of heavy metal contents in surface water samples 40
2.4.3. Quality control of analytical methods 43
CHAPTER 3: RESULTS AND DISCUSSION 45
3.1. Optimizations of some chemical factors influencing to absorbance in F- AAS
method 45
3.1.1. Study the effects of sample matrix and matrix modifier to F-AAS 45
3.1.2. Calibration curves of Pb, Cd, Zn and Cu measurements. 49
3.1.3. Limit of detection (LOD) and Limit of quantitation (LOQ) 53
3.1.4. Effect of interferences to the determination of Pb, Cd and Cu, Zn by
FAAS. 54
3.2. Determination of Pb, Cu, Zn, Cd in surface water samples using ICP-MS 57
3.2.1. Calibration curves for the determination of Cu, Zn, Pb and Cd in water
samples. 57
3.2.2. Method validation 59
3.3. Total concentrations of Cu, Pb, Cd, Zn in surface water and sediment of
ThadLuang marsh 60
3.3.1. Water sample: 60
3.3.2. Sediment sample 60
3.4. Application of GIS to find out spartial distribution of heavy metals 64
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CHAPTER 4: CONCLUSION ….66
REFERENCE 65

List of figures
Figure 1.1: Target Villages around ThadLuang Marsh
Figure 2.1: Spectrometer atomic absorption novAA 6800, Shimazhu
Figure 2.2: The map of Thatluang marsh showing water sampling sites.
Figure 2.3: The map of Thadluang marsh showing sediment sampling sites.
Figure 2.4: Operation principle of an atomic absorption spectrometer
Figure 2.5: Block diagram of atomic absorption spectrometer
Figure 2.6: Instrumentation for low-resolution ICP-MS.
Figure 3.1: The investigation of linear ranges for the determination of Pb, Cd, Zn and
Cu using F-AAS
Figure 3.2: The calibration curves for the determinations of Pb, Cd, Zn and Cu in
standard solutions
Figure 3.3: Calibration curves for the determination of Cu, Cd, Pb and Zn using ICP-
MS.
Figure 3.4: The Map of water quality of Thadluang Marsh.
Figure 3.5: The Map of sediment quality of Thadluang Marsh.









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List of tables
Table 1.1: Some data published on pollution in ThadLuang marsh
Table 2.1: Characteristics of the sampling points in Thadluang marsh
Table 2.2: Characteristics of the sediment points in Thadluang marsh
Table 2.3: The optimal conditions of F-AAS for measuring Pb, Cd, Zn, Cu
Table 2.4: The experimental conditions for determination of Cu, Pb, Cd and Zn using
ICP- MS techniques
Table 3.1: Investigation of HNO
3
and NH
4
CH
3
COO effects on analysis of Pb, Cd, Cu
and Zn
Table 3.2: Two - way ANOVA table for evaluating effects of HNO
3
and
NH
4
CH
3
COO
Table 3.3: Influence of types of acid media HCl, HNO
3

and H
2
SO
4
effects on Cu
2+

and Pb
2+
analysis
Table 3.4: The absorbance of each metal atom (after subtracting the absorbance of
the blank solution) vs. their concentrations
Table 3.5: The absorbance of each heavy metal standard solutions in the linear range
of concentrations
Table 3.6: LOD and LOQ of the determination of Pb, Cd, Zn and Cu using F-AAS
method
Table 3.7: Result of errors and repeatability of the measurements
Table 3.8: Accuracy and recovery of CRM using FAAS and ICP-MS
Table 3.9: The concentration of Pb, Cd, Zn, Cu in surface water samples of
ThadLuang Marsh (g/L)
Table 3.10: Heavy metal content (mg/kg) in sediment collected in Thadluang marsh.
Table 3.11: Proposed Surface Water Quality standard

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List of abbreviations

Lao PDR
The Lao People’s Democratic Republic
EDTA
Ethylene-diamine-tetracetic acid
DME
Dropping mercury electrode
SMDE
Static mercury drop electrode
AES
Atomic emission spectroscopy
F-AAS
Flame Atomic absorption spectroscopy
ICP-Ms
Inductive couple plasma – mass spectrophotometry
ANOVA
The analysis of variance
LOL
The limit of linearity
LOD
Limit of detection
LOQ
Limit of quantitation

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INTRODUCTION

The Lao People’s Democratic Republic (Lao PDR) is a small landlocked and
sparsely populated country in the South East Asia. Laos is characterized by two main
geographical zones: the central plains along the Mekong River and the mountainous
regions to the north, east and south. Lao PDR has a land area of 236,800 square
kilometers (sq. km.). It is long and slender, the length from north to south is nearly
1,000 kilometers and the width has only 150 kilometers to 400 kilometers. [STEA,
2004] The total population is approximately 5,621,982 people, in which women
accounted for 51%, according to the 2005 population and housing census. The
population density of the country is around 24 people per hectare which is the lowest
population densities in Asia. 39% of Lao population is classified as poor and 36% are
under poverty line. [MRC, 2006] Their living condition depends on nature, hunting
wildlife, foraging for forest products and practicing slash and burn cultivation for
their crops with a low profit in order to survive.

Lao PDR has rich water resources, mainly good quality fresh water. The amount of
average water flow in the Mekong and its tributaries amount to about 8,500 m
3
/s.
Currently most of the water occurs in the agricultural sector, for instance, irrigation,
fisheries, plantations and livestock watering. 60 percent of urban population and 51
percent of rural population has access to clean water. [Draft Agreement, March 2009]
The total of annual water flow in Lao PDR is estimated at 270 billion cubic meters,
equivalent to 35% of the average annual flow of the whole Mekong Basin. The
monthly distribution of the flow of the rivers in Lao PDR closely follows the pattern
of rainfall: about 80% during the rainy season (May-October) and 20% in the dry
season, from November to April. For some rivers in the central and southern parts of
the country (particularly Se Bang Fai, Se Bang Hieng and Se Done) the flow in the
dry season is less: around 10 to 15% of the annual flow. [Agricultural Statistics
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[April 2005]. The rivers outside the Mekong Basin flow through Viet Nam into the
South China Sea. These rivers are Nam Ma, Nam Sam, and Nam Neune. The limited
information on these rivers restricts assessment of their potential.
Most of the water use occurs in the agricultural sector such as irrigation, fisheries,
plantations and livestock watering. In addition the water is used for hydro-power; the
country has the potential to produce 23,000 megawatts of electricity. Currently 5% of
that capacity has been exploited. [Would Back, 2007] The plenteous supply of water
in Lao PDR, especially in the rainy season, provides good condition for water
transport, industrial development and water supply. Sixty percent of urban
population and 51 % of rural population has access to clean water.

Currently there are some problems related to waste and polluted water in major urban
areas from varied community use (residential density, hotels, hospitals and
entertainments centers). In addition there is water pollution from agricultural and
industrial sectors, including mineral exploitation. This is not a major problem now,
but the problem could escalate. The degradation of natural water and water
catchments from sedimentation, land erosion and drying out continues.
However, as continued development takes place in all of these areas, increasing
scarcity and competition for water can be expected. Increasing impacts of
development on water quality and on human health and the natural environment will
also take place. Finally, floods and drought can have serious negative impacts and
may, in fact, increase as climate change takes place.
Vientiane Capital is located on an alluvial plain along the left bank of Mekong River
east to west. The area of Vientiane is about 3,920 km
2
and the elevation of the ground
ranges from 160 m to 170 m above the sea level. The city comprises 9 districts;
Chanthabuly, Hadxayfong, Meungparkngum, Naxaithong Sangthong, Sikhottabong,
Sisattanak, Saysettha and Xaythany. The population is around 672,912 people. The
area designated for urbanization extends along the left bank of Mekong River and
occupies an area of 210 km
2
. [JICA, 2009] For Thadluang wetland, its water quality
is a part of the water quality-monitoring project of Mekong Secretariat, in the vicinity
of Vientiane Capital City. Main problems found are wastewater and sewage (from
the city area) discharged into the marsh.
Especially, no sooner do many factories appear and develop increasing fast than
water is polluted by heavy metals is over allowable limit. Owing to not taking part in
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biochemical process, heavy metals such as Cd, Pb, Zn, Cu … are accumulated in
human body, which leads to harmfulness for organism. The fact that water is polluted
by heavy metal is often seen in rivers near industrial area, big cities and minerals
exploiting area. The main reason leading to heavy metals pollution is pouring into
water environment a large amount of industrial and untreated wastewater. Pollution
by heavy metals accumulated through foods directly into organism has negative
effects on life environment. In order to reduce consequence of this problem, it is
necessary to cultivate measures of water treatment.

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CHAPTER 1: OVERVIEW OF WATER AND SEDIMENT
POLLUTION IN THADLUANG MARSH
1.1. Topography of Thad Luang marsh
The ThadLuang Marshland is the largest remaining wetland in Vientiane
Municipality, located on the eastern edge of the capital city of Lao PDR. The marsh
itself is approximately 20 km
2
and is a part of the ThadLuang Basin drained from
Vientiane City and surrounding areas. A large portion of the wetland has been
converted to rice cultivation although changes in water regimes have resulted in
annual floods and cultivation has been limited to between 700 - 1000 ha
(approximately half of the wetland area) in recent years. The remaining area is
covered with permanent and seasonal aquaculture ponds, shrub and grassland, and
peat land. [NUOL, March, 2002] Water draining into the ThadLuang Marshland
comes primarily from irrigation canal at the Donnokkoom rice field, Hong Ke and
Hong Xeng stream, which collects its water from drainage canals running throughout
Vientiane. Water running out of the marsh follows Houay Mak Hiao River dumping
into the Mekong 64 km south east of Vientiane.

Based on a recent government survey in the That Lung area, about 90 percent
of households around ThadLuang Marsh are classified as poor and only 10 percent of
households as relatively better off category. Because of the structure of rural
employment, the livelihoods of households around ThadLuang Marsh are highly
depended upon the ThadLuang marsh, and the water resources availability at the
marsh. This is because agriculture and sale of agriculture produce are the primary
income generating activity for over 70 % of households living around the ThadLuang
marsh. About 7 percent of the total households there are without a primary form of
income from agriculture (farming), and it is likely that they rely heavily on collecting
fish and aquatic produce from the marsh area. [STO, 2009] Therefore, being one of
main reasons leading to poverty, water and sediment pollution in ThadLuang marsh
affect significantly on life of people here.



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Figure 1.1.Villages around ThadLuang Marsh

1.2. Present status of water and sediment pollution in ThadLuang marsh
ThadLuang Marsh receives domestic sewage discharge from a large
proportion of Vientiane city by way of several canals. While Vientiane has a
sewerage system, there is currently no functioning waste treatment facility near the

urban area. Sewage is either hauled to a waste treatment plant 17 km outside of the
city limits or, more commonly, discharged into natural water bodies, either as raw
wastes or as seepage from septic tanks. Sewerage and sanitation systems rely on the
infiltration of wastewater into the ground. However due to the low soil permeability
and the high groundwater table in Vientiane, many soak ways fail to operate
efficiently meaning that sewage is discharged from tanks and drains directly into
urban wetlands. As a result of considerable quantity of household waste and sewage
is discharged into Nong Chang, and then flows into ThadLuang Marsh before
entering the Mekong. Textile, detergent and paper plants discharge directly into open
drains without any treatment, and contribute wastewaters into ThadLuang Marsh.
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There are two tanneries although the larger of these has sophisticated treatment
facilities, in practice wastes bypass these and are discharged untreated. The brewery
on the southern shore of ThadLuang passes waste through an oxidation pond.
Because of the importance of ThadLuang with issues directly relating to
Vientiane environment, it is irrefutable that researching water pollution in
ThadLuang is necessary and must be done immediately. Some data published on
pollution in ThadLuang marsh is shown in table 1.1.

Table 1.1: Some data published on pollution in ThadLuang marsh.
Parameters
Unit
2002
2003
Standard

(STEA, 2000)

pH
(mg/l)
7.8
8.8
6 – 9.5
Temperature
o
C
28
32.6
*
Electrical Conductivity (EC)
(micro/cm)
266
438
*
Dissolve Oxygen (DO)
mg/l
2.8
1.1
>2
Biological Oxygen Demand (BOD)
mg/l
39
78.3
4
Ammonia nitrogen (NH
3

-N)
mg/l
0.294
0.389
0.2
Nitrate-Nitrogen (NO
3
-N)
mg/l
3.064
3.991
<5.0
PO
4
-P
(mg/l)
5.4
6.45
30
Total-N
(mg/l)
5.6
3.19
*
Total-P
(mg/l)
*
5.951
*

This table only mentions about some norms such as BOD, COD, EC, DO …
Most scientific research has shown that there is no data on heavy metals pollution
until now. This study will provide more information to this missing part. According
to this table, pH, BOD, Ammonia nitrogen (NH
3
-N) and PO
4
-P parameters are much
higher than standard while Dissolve Oxygen (DO) and Nitrate-Nitrogen (NO
3
-N) are
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lower. There is sound that water pollution appears compared to Surface Water
Quality Standard in Lao PDR. Also, by the fact that it exist wastewater and sewage
(from the city area) discharged into the marsh. Especially, no sooner do many
factories appear and develop increasing fast than water is polluted by heavy metals is
over allowable limit.

1.3. Toxicity of Cadmium Cd, Copper Cu, Lead Pb, Zinc Zn
1.3.1. Cadmium Cd
The most dangerous form of occupational exposure to cadmium is inhalation
of fine dust and fumes, or ingestion of highly soluble cadmium compounds.
Inhalation of cadmium-containing fumes can result initially in metal fume fever but
may progress to chemical pneumonitis, pulmonary edema, and death. [Ayres, Robert
U, 2003]

Cadmium is also an environmental hazard. Human exposures to environmental
cadmium are primarily the result of fossil fuel combustion, phosphate fertilizers,
natural sources, iron and steel production, cement production and related activities,
nonferrous metals production, and municipal solid waste incineration. However,
there have been a few instances of general population toxicity as the result of long-
term exposure to cadmium in contaminated food and water. In the decades leading up
to World War II, Japanese mining operations contaminated the Jinzū River with
cadmium and traces of other toxic metals.[National Research Council (U.S.), 1969) ]
As a consequence, cadmium accumulated in the rice crops growing along the
riverbanks downstream of the mines. Some members of the local agricultural
communities consuming the contaminated rice developed itai-itai disease and renal
abnormalities, including proteinuria and glucosuria.
The victims of this poisoning were almost exclusively post-menopausal
women with low iron and other mineral body stores. Similar general population
cadmium exposures in other parts of the world have not resulted in the same health
problems because the populations maintained sufficient iron and other mineral levels.
Thus, while cadmium is a major factor in the itai-itai disease in Japan, most
researchers have concluded that it was one of several factors. Cadmium is one of six
substances banned by the European Union's Restriction on Hazardous Substances
(RoHS) directive, which bans certain hazardous substances in electrical and
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electronic equipment but allows for certain exemptions and exclusions from the
scope of the law.
Although some studies linked exposure to cadmium with lung and prostate
cancer, there is still a substantial controversy about the carcinogenicity of cadmium.

More recent studies suggest that arsenic rather than cadmium may lead to the
increased lung cancer mortality rates. Furthermore, most data regarding the
carcinogenicity of cadmium rely on research confounded by the presence of other
carcinogenic substances.
Tobacco smoking is the most important single source of cadmium exposure in
the general population. It has been estimated that about 10% of the cadmium content
of a cigarette is inhaled through smoking. The absorption of cadmium from the lungs
is much more effective than that from the gut, and as much as 50% of the cadmium
inhaled via cigarette smoke may be absorbed. [Jarup, L. (1998)]
On average, smokers have 4-5 times higher blood cadmium concentrations
and 2 - 3 times higher kidney cadmium concentrations than non - smokers. Despite
the high cadmium content in cigarette smoke, there seems to be little exposure to
cadmium from passive smoking. No significant effect on blood cadmium
concentrations has been detected in children exposed to environmental tobacco
smoke.
Cadmium exposure is a risk factor associated with early atherosclerosis and
hypertension, which can both lead to cardiovascular disease.
1.3.2. Copper Cu
Copper toxicity refers to the consequences of an excess of copper in the body.
Copper toxicity can occur from eating acid food that has been cooked in un-coated
copper cookware, or from exposure to excess copper in drinking water or other
environmental sources.
Copper in the blood exist in two forms: bound to ceruloplasmin (85–95%) and
the rest "free" loosely bound to albumin and small molecules. Free copper causes
toxicity as it generates reactive oxygen species such as superoxide, hydrogen
peroxide, the hydroxyl radical. These damage proteins, lipids and DNA.

[Federal
Register, 1976]
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Acute symptoms of copper poisoning by ingestion include vomiting,
hematemesis (vomiting of blood), hypotension (low blood pressure), melena (black
"tarry" feces), coma, jaundice (yellowish pigmentation of the skin), and
gastrointestinal distress. Individuals with glucose-6-phosphate deficiency may be at
increased risk of hematologic effects of copper. Hemolytic anemia resulting from the
treatment of burns with copper compounds is infrequent.
Chronic (long-term exposure) effects of copper exposure can damage the liver
and kidneys. Mammals have efficient mechanisms to regulate copper stores such that
they are generally protected from excess dietary copper levels.
The U.S. Environmental Protection Agency's Maximum Contaminate Level (MCL)
in drinking water is 1.3 milligrams per Liter. The MCL for copper is based on the
expectation that a lifetime of consuming copper in water at this level is without
adverse effect (gastrointestinal effect). The U.S EPA lists evidence that copper
causes testicular cancer as "most adequate" according to the latest research at
Sanford-Burnham Medical Research Institute. The Occupational Safety and Health
Administration (OSHA) has set a limit of 0.1 mg/m3 for copper fumes (vapor
generated from heating copper) and 1 mg/m3 for copper dusts (fine metallic copper
particles) and mists (aerosol of soluble copper) in workroom air during an 8-hour
work shift, 40-hour workweek. [Curtis D. Klassen, Ph.D., McGraw-Hill]
1.3.3. Lead Pb
Lead is a poisonous metal that can damage nervous connections (especially in
young children) and cause blood and brain disorders. Lead poisoning typically
results from ingestion of food or water contaminated with lead; but may also occur
after accidental ingestion of contaminated soil, dust, or lead based paint. Long-term
exposure to lead or its salts (especially soluble salts or the strong oxidant PbO

2
) can
cause nephropathy, and colic-like abdominal pains. The effects of lead are the same
whether it enters the body through breathing or swallowing. Lead can affect almost
every organ and system in the body. The main target for lead toxicity is the nervous
system, both in adults and children. Long-term exposure of adults can result in
decreased performance in some tests that measure functions of the nervous system. It
may also cause weakness in fingers, wrists, or ankles. Lead exposure also causes
small increases in blood pressure, particularly in middle-aged and older people and
can cause anemia. Exposure to high lead levels can severely damage the brain and
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kidneys in adults or children and ultimately cause death. In pregnant women, high
levels of exposure to lead may cause miscarriage. Chronic, high-level exposure has
shown to reduce fertility in males. The antidote/treatment for lead poisoning consists
of dimercaprol and succimer.
The concern about lead's role in cognitive deficits in children has brought
about widespread reduction in its use (lead exposure has been linked to learning
disabilities). Most cases of adult elevated blood lead levels are workplace-
related. High blood levels are associated with delayed puberty in girls. Lead has been
shown many times to permanently reduce the cognitive capacity of children at
extremely low levels of exposure.
During the 20th century, the use of lead in paint pigments was sharply reduced
because of the danger of lead poisoning, especially to children.

By the mid-1980s, a

significant shift in lead end-use patterns had taken place. Much of this shift was a
result of the U.S. lead consumers' compliance with environmental regulations that
significantly reduced or eliminated the use of lead in non-battery products,
including gasoline, paints, solders, and water systems. Lead use is being further
curtailed by the European Union's RoHS directive. Lead may still be found in
harmful quantities in stoneware, vinyl (such as that used for tubing and the insulation
of electrical cords), and brass manufactured in China. Between 2006 and 2007 many
children's toys made in China were recalled, primarily due to lead in paint used to
color the product. [Stellman, Jeanne Mager (1998).]
Older houses may still contain substantial amounts of lead paint. White lead
paint has been withdrawn from sale in industrialized countries, but the yellow lead
chromate is still in use; for example, Holland Colours Holcolan Yellow. Old paint
should not be stripped by sanding, as this produces inhalable dust.
Lead salts used in pottery glazes have on occasion caused poisoning, when
acidic drinks, such as fruit juices, have leached lead ions out of the glaze. It has been
suggested that what was known as "Devon colic" arose from the use of lead-lined
presses to extract apple juice in the manufacture of cider. Lead is considered to be
particularly harmful for women's ability to reproduce. Lead (II) acetate (also known
as sugar of lead) was used by the Roman Empire as a sweetener for wine, and some
consider this to be the cause of the dementia that affected many of the Roman
Emperors.
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Lead as a soil contaminant is a widespread issue, since lead is present in
natural deposits and may also enter soil through (leaded) gasoline leaks from
underground storage tanks or through a waste stream of lead paint or lead grindings

from certain industrial operations.
Lead can also be found listed as a criteria pollutant in the United States Clean
Air Act section 108. Lead that is emitted into the atmosphere can be inhaled, or it can
be ingested after it settles out of the air. It is rapidly absorbed into the bloodstream
and is believed to have adverse effects on the central nervous system, the
cardiovascular system, kidneys, and the immune system. [Hong, Youlian and
Bartlett, Roger, ed (2008)].
In the human body, lead inhibits porphobilinogen synthase and ferrochelatase,
preventing both porphobilinogen formation and the incorporation of iron into
protoporphyrin IX, the final step in hemi synthesis. This causes ineffective hemi
synthesis and subsequent microcytic anemia. At lower levels, it acts as a calcium
analog, interfering with ion channels during nerve conduction. This is one of the
mechanisms by which it interferes with cognition. Acute lead poisoning is treated
using disodium calcium edentate: the calcium chelae of the disodium salt of
ethylene-diamine-tetracetic acid (EDTA). This chelating agent has a greater affinity
for lead than for calcium and so the lead chelae is formed by exchange. This is then
excreted in the urine leaving behind harmless calcium.

1.3.4. Zinc Zn
Although zinc is an essential requirement for good health, excess zinc can be
harmful. Excessive absorption of zinc suppresses copper and iron absorption. The
free zinc ion in solution is highly toxic to plants, invertebrates, and even vertebrate
fish. The Free Ion Activity Model is well-established in the literature, and shows that
just micro molar amounts of the free ion kills some organisms. A recent example
showed 6 micro molar killing 93% of all Daphnia in water. [Barceloux, Donald G.;
(1999)].
The free zinc ion is a powerful Lewis acid up to the point of being corrosive.
Stomach acid contains hydrochloric acid, in which metallic zinc dissolves readily to
give corrosive zinc chloride. Swallowing a post-1982 American one cent piece
(97.5% of zinc) can cause damage to the stomach lining due to the high solubility of

the zinc ion in the acidic stomach.
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There is evidence of induced copper deficiency at low intakes of 100–300 mg
Zn/day; a recent trial had higher hospitalizations for urinary complications compared
to placebo among elderly men taking 80 mg/day [Fosmire GJ (1990)]. The USDA
RDA is 11 and 8 mg Zn/day for men and women, respectively. Even lower levels,
closer to the RDA, may interfere with the utilization of copper and iron or adversely
affect cholesterol. Levels of zinc in excess of 500 ppm in soil interfere with the
ability of plants to absorb other essential metals, such as iron and manganese. There
is also a condition called the zinc shakes or "zinc chills" that can be induced by the
inhalation of freshly formed zinc oxide formed during the welding of galvanized
materials.
The U.S. Food and Drug Administration (FDA) has stated that zinc damages
nerve receptors in the nose, which can cause anomies. Reports of anomies were also
observed in the 1930s when zinc preparations were used in a failed attempt to
prevent polio infections. On June 16, 2009, the FDA said that consumers should stop
using zinc-based intranasal cold products and ordered their removal from store
shelves. The FDA said the loss of smell can be life-threatening because people with
impaired smell cannot detect leaking gas or smoke and cannot tell if food has spoiled
before they eat it. Recent research suggests that the topical antimicrobial zinc
pyrithione is a potent heat shock response inducer that may impair genomic integrity
with induction of PARP-dependent energy crisis in cultured human keratinocytes
and melanocytes.
In 1982, the United States Mint began minting pennies coated in copper but
made primarily of zinc. With the new zinc pennies, there is the potential for zinc

toxic sis, which can be fatal. One reported case of chronic ingestion of 425 pennies
(over 1 kg of zinc) resulted in death due to gastrointestinal bacterial and fungal
sepsis, while another patient, who ingested 12 grams of zinc, only showed lethargy
and ataxia (gross lack of coordination of muscle movements). Several other cases
have been reported of humans suffering zinc intoxication by the ingestion of zinc
coins.
Pennies and other small coins are sometimes ingested by dogs, resulting in the
need for medical treatment to remove the foreign body. The zinc content of some
coins can cause zinc toxicity, which is commonly fatal in dogs, where it causes a
severe hemolytic anemia, and also liver or kidney damage; vomiting and diarrhea are
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possible symptoms. Zinc is highly toxic in parrots and poisoning can often be fatal.
The consumption of fruit juices stored in galvanized cans has resulted in mass parrot
poisonings with zinc.
1.4. Analytical methods for determination of heavy metals in water and
sediment samples
1.4.1. Electrochemical methods
1.4.1.1. Polarography
Polarography is a subclass of voltammetry where the working electrode is
a dropping mercury electrode (DME) or a static mercury drop electrode (SMDE)
useful for its wide cathodic range and renewable surface. It was invented by Jaroslav
Heyrovský, who was for this invention awarded by Nobel’s prize in 1959.
Polarography is an voltammetric measurement whose response is determined
by combined diffusion/convection mass transport. Polarography is a specific type of
measurement that falls into the general category of linear-sweep voltammetry where

the electrode potential is altered in a linear fashion from the initial potential to the
final potential. As a linear sweep method controlled by convection/diffusion mass
transport, the current vs. potential response of a polarographic experiment has the
typical sigmoidal shape. What makes polarography different from other linear sweep
voltammetry measurements is that polarography makes use of the dropping mercury
electrode (DME) or the static mercury dropping electrode.
A plot of the current vs. potential in a polarography experiment shows the
current oscillations corresponding to the drops of Hg falling from the capillary. If one
connected the maximum current of each drop, a sigmoidal shape would result. The
limiting current (the plateau on the sigmoid), called the diffusion current because
diffusion is the principal contribution to the flux of electro active material at this
point of the Hg drop life.
The method has been used for the determination of heavy metals. In Vietnam,
Tu Van Mac and Tran Thi Sau has studied about determination of copper, lead and
cadmium in beer in Hanoi by alternating current differential pulse polarography with
sensitivity accounting for 1ppb. [Tu Van Mac, Tran Thi Sau]
Thanh Thuc Trinh, Nguyen Xuan Lang and their colleagues has applied
polarimetry on determination of Zinc, Cadmium, Lead and Copper in some kinds of
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food and agricultural soil. It is experimented in environment of acetate buffer with
system of 3 polars: hanging mercury drop electrode, reference electrode Ag/AgCl,
auxiliary electrode Pt and electrodeionization potential accounting for -1.05V in 60
seconds [Thanh Thuc trinh, Nguyen Xuan Lang].
1.4.1.2. Voltammetry
Voltammetry is a category of electroanalytical methods used in analytical

chemistry and various industrial processes. In voltammetry, information about
an analyte is obtained by measuring the current as the potential is varied.
Voltammetry experiments investigate the half cell reactivity of ananalyte.
Voltammetry is the study of current as a function of applied potential. These curves I
= f(E) are called voltammograms. The potential is varied arbitrarily either step by
step or continuously and the actual current value is measured as the dependent
variable. The opposite, i.e., amperometry, is also possible but not common. The
shape of the curves depends on the speed of potential variation (nature of driving
force) and on whether the solution is stirred or quiescent (mass transfer). Most
experiments control the potential (volts) of an electrode in contact with the analyte
while measuring the resulting current (amperes). [Zoski, Cynthia G. (2007-02-07)].
Professor Petrovic and his colleagues used Differential pulse stripping
voltametry to determine Cd and Pb in water after separating them from humic acid
by thin layer chromatographic method. [Petrovic and Dewal, 1998]
Selehattin Yilmaz, Sultan Yagmur, Gulsen Saglikoglu, Murat Sadikoglu
studied about direct determination of zinc heavy metal in the tap water carried out by
differential pulse anodic stripping voltammetry technique at the glassy carbon
electrode (GCE). The zinc ions were deposited by reduction at -1.5 V on a bare
glassy carbon surface. Then, the deposited metal was oxidized by scanning the
potential of the electrode surface from -1.5 to -0.8 volt using a differential puls mode.
The stripping current arising from the oxidation of metal was connected with the
concentration the metal in the sample. The concentration of zinc heavy metal found
in tap water sample was determined to be 180 mg L
-1
using 0.2 mol L
-1
acetate buffer
(pH: 3.50) [Selehattin Yilmaz, 2009].
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1.4.2. Spectrophotometric methods
1.4.2.1. Ultraviolet-visible spectrophotometer
Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometer (UV-
Vis or UV/Vis) refers to absorption spectroscopy or reflectance spectroscopy in
the ultraviolet-visible spectral region. This means it uses light in the visible and
adjacent (near-UV and near-infrared (NIR)) ranges. The absorption or reflectance in
the visible range directly affects the perceived color of the chemicals involved. In
this region of the electromagnetic spectrum, molecules undergo electronic
transitions. [ Prabhakar, Dubinskii, Editors and Dekker (2002)]. This technique is
complementary to fluorescence spectroscopy, in that fluorescence deals with
transitions from the excited state to the ground state, while absorption measures
transitions from the ground state to the excited state. UV/Vis spectroscopy is
routinely used in analytical chemistry for the quantitative determination of different
analytes, such as transition metal ions, highly conjugated organic compounds, and
biological macromolecules. Determination is usually carried out in solutions.
Gao Hong – Wen (China) used dithizone combining with Cd separation cells
filter to determination of Cd (II) in sea water by UV/Vis spectroscopy with LOD is
0.006 ppm. [Gao Hong – Wen (1995),]
A.M Garcia Rodriguez, A Garcia de Torres and J.M Cano Pavon studied
about simultaneous determination of iron, cobalt, nickel and copper by UV-visible
spectrophotometry with multivariate calibration. Linear determination ranges of Co,
Ni, Fe and Cu are 0.2–1.3 mg/ml, 0.1–1.2 mg/ml, 0.1–1.1 mg/ml and 0.2–1.2 mg/ml
respectively.A method for the simultaneous spectrophotometric determination of the
divalent ions of iron, cobalt, nickel and copper based on the formation of their
complexes with 1,5-bis(di-2-pyridylmethylene) thiocarbonohydrazide (DPTH) is
proposed.[A.M Garcia, A Garcia and J.M Cano (1998)]

1.4.2.2. Atomic emission spectroscopy (AES)
Atomic emission spectroscopy (AES) is a method of chemical analysis that
uses the intensity of light emitted from a flame, plasma, arc, or spark at a particular
wavelength to determine the quantity of an element in a sample. The wavelength of
the atomic spectral line gives the identity of the element while the intensity of the
emitted light is proportional to the number of atoms of the element. A sample of a
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material (analyte) is brought into the flame as a gas or sprayed solution. [Stefánsson
A, Gunnarsson I, Giroud N (2007)]. The heat from the flame evaporates the solvent
and breaks chemical bonds to create free atoms. The thermal energy also excites the
atoms into excited electronic states that subsequently emit light when they return to
the ground electronic state. Each element emits light at a characteristic wavelength,
which is dispersed by a grating or prism and detected in the spectrometer. A frequent
application of the emission measurement with the flame is the regulation of alkali
metals for pharmaceutical analytics
Krzysztof Jankowski

, Jun Yao, Krzysztof Kasiura, Adrianna Jackowska,
Anna Sieradzka studied about multielement determination of heavy metals in
water samples by continuous powder introduction microwave-induced plasma atomic
mission spectrometry after preconcentration on activated carbon. The experimental
setup consisted of integrated rectangular cavity TE and vertically positioned plasma
torch. The satisfactory signal stability required for sequential analysis was attained
owing to the vertical plasma configuration, as well as the plasma gas flow rate
compatibility with sample introduction flow rate. The elements of interest (Cd, Cu,

Cr, Fe, Mn, Pb, Zn) were preconcentrated in a batch procedure at pH 8–8.5 after
addition of activated carbon and then, after filtering and drying of the activated
carbon suspension, introduced to the MIP by the CPI system. [Krzysztof Jankowski

,
Jun Yao, Krzysztof Kasiura, Adrianna Jackowska, Anna Sieradzka (2004)].
1.4.2.3. Atomic absorption spectroscopy (AAS)
Atomic absorption spectroscopy (AAS) is a spectroanalytical procedure for
the qualitative and quantitative determination of chemical elements employing the
absorption of optical radiation (light) by free atoms in the gaseous state. In analytical
chemistry the technique is used for determining the concentration of a particular
element (the analyte) in a sample to be analyzed. AAS can be used to determine over
70 different elements in solution or directly in solid samples. The technique makes
use of absorption spectrometry to assess the concentration of an analyte in a sample.
It requires standards with known analyte content to establish the relation between the
measured absorbance and the analyte concentration and relies therefore on Beer-
Lambert Law. In short, the electrons of the atoms in the atomizer can be promoted to
higher orbitals (excited state) for a short period of time (nanoseconds) by absorbing a
defined quantity of energy (radiation of a given wavelength). [B.V L’vov (2005)]
This amount of energy, i.e., wavelength, is specific to a particular electron transition