ANALYSIS OF SOME METALS IN SOME UNBRANDED TEA PURCHASED IN SOME
SELECTED MARKETS WITHIN KADUNA METROPOLISE.
BY
MUHAMMAD IDRIS RABAKPAN
KPT/CST/19/40370
DEPARETMENT OF APPLIED CHEMISTRY
COLLEGE OF SCIENCE AND TECHNOLOGY
SCHOOL OF APPLIERD SCIENCE KADUNA POLYTECHNIC
JULY, 2022
i
TITLE PAGE
ANALYSIS OF SOME METALS IN SOME UNBRANDED TEA PURCHASED IN SOME
SELECTED MARKETS WITHIN KADUNA METROPOLISE.
BY
MUHAMMAD IDRIS RABAKPAN
KPT/CST/19/40370
DEPARTMENT OF APPLIED CHEMISTRY
COLLEGE OF SCIENCE AND TECHNOLOGY
SCHOOL APPLIED CHEMISTRY
KADUNA POLYTECHNIC
THIS PROJECT IS SUBMITTED TO DEPARTMENT OF APPLIED
CHEMISTRY, COLLEGE OF SCIENCE AND TECHNOLOGY, SCHOOL
APPLIED CHEMISTRY KADUNA POLYTECHNIC.
IN PARIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD
OF HIGHER NATIONAL DIPLOMA (HND) IN SCIENCE LABORATORY
TECHNOLOGY (CHEMISTRY/BIOCHEMISTRY)
JULY, 2022
ii
DECLARATION
I here by declare that this research project has been conducted by me under the supervision of
Dr. S.S. Mohammed of Applied chemistry department, Kaduna polytechnic. It is completely
my work and has notbeen submitted in any form for another degree of higher national
diploma.
__________________________
__________________________
MUHAMMAD IDRIS RABAKPAN
DATE
KPT/CST/19/40370
iii
APPROVAL PAGE.
This is to certify that this research work is an original work undertaken by MUHAMMAD
IDRIS RABAKPAN. It is submitted to the department of applied chemistry in partial
fulfilment of the requirement for the award of higher national diploma in science laboratory
technology(S.L.T) in co-ordnance with the rules and regulation of project.
___________________________
____________________________
DR. S.S. MOHAMMED
DATE
(PROJECT SUPERTVISOR)
___________________________
____________________________
DR. M. M. IMAM
DATE
(PROJECT CORDINATOR)
___________________________
____________________________
DR. M.I. KAMGIWA
DATE
(HEAD OF DEPARTMENT)
___________________________
____________________________
EXTERNAL SUPERVISOR
DATE
iv
DEDICATION
This project report is dedicated to almighty Allah, for his faithfulness and mercy, who
bestowed on me the strength and power to see the successful completion of this program
Also, it is dedicated to my loving parents for their parental decision to educate me, and their
support to see the achievement of this goal,
v
ACKNOWLEDGEMENT
With a heart full of gratitude, I express my gratitude to Almighty Allah, the finisher of our
faith and made it possible for me to carry out this research successful.
I wish to acknowledge and express my sincere gratitude toward my supervisor DR. S.S.
MOHAMMED who took the pain to read through every page of this write up and never
relented in contributing useful ideas and suggestions throughout the period of my project.
My appreciation goes to my Head OF Department MAL. MOHAMMED SANI MSHILIA
and the entire member and staff of applied chemistry department whose effort made it
possible for me to acquire the maximum knowledge in chemistry/ biochemistry.
My profound gratitude goes to my beloved sister and her husband for the caring advice and
encouragement.
And finally to my beloved family and friend of same academic pursuit who have also
contributed, I acknowledge your support and may God bless you abundantly
vi
TABLE OF CONTENT
TITLE PAGE .................................................................................................................................................... ii
DECLARATION ............................................................................................................................................. iii
APPROVAL PAGE. ....................................................................................................................................... iv
DEDICATION .................................................................................................................................................. v
ACKNOWLEDGEMENT .............................................................................................................................. vi
TABLE OF CONTENT ................................................................................................................................. vii
ABSTRACT ...................................................................................................................................................... x
CHAPTER ONE
1.0
Introduction .......................................................................................................................................... 1
1.1
Background of the Study .................................................................................................................... 1
1.2
Unbranded tea of interest .................................................................................................................... 4
1.2.1
Green Tea .............................................................................................................................................. 4
1.2.2
Black Tea .............................................................................................................................................. 4
1.3
Significance of the Study .................................................................................................................... 5
1.4
Statement of the Problems .................................................................................................................. 5
1.5
Aim ........................................................................................................................................................ 6
1.6
Objectives ............................................................................................................................................. 6
CHAPTER TWO
LITERATURE REVIEW ................................................................................................................................ 7
2.0
Metals ................................................................................................................................................... 7
2.1
Metal in Tea......................................................................................................................................... 8
2.2
Toxic Effect Of Metals ....................................................................................................................... 9
2.3
Metal analysis ..................................................................................................................................... 10
2.4
Heavy metal of Interest ..................................................................................................................... 11
2.4.1
Lead (Pb) ............................................................................................................................................. 11
2.4.2
Cadmium (Cd) .................................................................................................................................... 11
2.4.3
Zinc ...................................................................................................................................................... 12
2.4.4
Calcium ............................................................................................................................................... 13
2.4.5
Magnesium ......................................................................................................................................... 14
2.5
Chemical Constituents of Tea .......................................................................................................... 14
vii
2.5.1
Polyphenols ........................................................................................................................................ 16
2.5.2. Minerals ................................................................................................................................................. 16
2.6
Aroma, Taste and Color of Tea ........................................................................................................ 16
2.6.1
Aroma of Made Tea........................................................................................................................... 17
2.6.2. Taste of Made Tea ............................................................................................................................... 17
2.6.3
Color of Made Tea ............................................................................................................................. 17
2.7
Biological Activity of Tea Chemical Constituents........................................................................ 18
2.7.1. Tea Polyphenols and Antioxidant Activity ...................................................................................... 18
2.7.2
Tea Polyphenols and the Risk of Cancer ........................................................................................ 18
2.7.3
Tea Polyphenols and the Risk Coronary Heart Disease ............................................................... 18
2.7.4
Antibacterial and antiviral effects of tea ......................................................................................... 19
2.7.5
Anti-Inflammatory Effects of Tea ................................................................................................... 20
2.7.6
Diabetes and Renal Failure Effects of Tea ..................................................................................... 20
2.7.7
Functionalities of tea and Tea Polyphenols in Animal Models ................................................... 21
2.7.8
Effects of Tea Polyphenols Against Other Diseases ..................................................................... 21
CHAPTER THREE
3.0
METHOD ........................................................................................................................................... 23
3.1
Preparation of standard solution ...................................................................................................... 23
3.1.1
Preparation of zinc chloride (ZnCl2) standard solution ................................................................ 23
3.1.2
Preparation of Calcium chloride (CaCl2) standard solution ......................................................... 23
3.1.3
Preparation of cadmium chloride (CdCl2) standard solution ....................................................... 24
3.1.4
Preparation of lead Chloride (PbCl2) standard solution ............................................................... 24
3.1.5
Preparation of Magnesium chloride (MgCl2) standard solution .................................................. 24
3.2
Sampling Collection and Sampling Preparation ............................................................................ 25
3.3
Material and Method ......................................................................................................................... 27
3.4
List of Apparatus and Instrument .................................................................................................... 28
3.5
List of Reagent ................................................................................................................................... 28
3.6
Methodology ...................................................................................................................................... 29
3.6.1
Sample Ashing and Digestion .......................................................................................................... 29
3.7
Instrumentation .................................................................................................................................. 30
3.7.1. Beer Lambert Law ............................................................................................................................. 30
viii
3.8
Basic Principle ................................................................................................................................... 31
CHAPTER FOUR
4.0.
RESULT ............................................................................................................................................. 32
CHAPTER 5
5.0.
DISCUSSION, RECOMMENDATION, CONCLUSSION. ....................................................... 35
5.1.
Discussion ........................................................................................................................................... 35
5.3
Conclusion .......................................................................................................................................... 40
5.4
Recommendation ............................................................................................................................... 41
Appendix .......................................................................................................................................................... 49
ix
ABSTRACT
Tea leaves can be source of mineral component and trace element as well as some
undesirable substances due to exposure to the environment. In this study, Mg, Zn, Ca, Cd, Pb
were analysed by atomic absorption spectrometer (AAS). Among the metals analysed, Ca
was the most abundant, ranging from 71.57±0.10mg/g to 116.74±0.10mg/g in all the tea
samples, Mg, Zn were also found in reasonable amounts. Fortunately, toxic heavy metals Cd
was not detected and Pb had the lowest concentration in all the sample with concentration
ranging from 0.26±0.10 to 0.82±0.11 across all the samples purchased in the various market.
x
CHAPTER ONE
1.0
Introduction
1.1
Background of the Study
Tea (Camellia sinensis ) is an ancient crop that has been cultivated for thousands of years
(Jianwei et al., 2016). Tea plant belongs to the Theaceaefamily. It is a woody perennial tree
crop and it is diploid crop with a chromosomal number of 30, though some triploid cultivar
(C. sinensisvar. macrophylla and C. rosaeflora) have been reported (Devarumath et al.,
2002). Drinking tea plays an important part in our lives, it is such a universal phenomenon
with millions of people around the world take the tea on a daily basis. It is very unimaginable
assuming a world without tea but the Eastern world has been using tea for more than 5000
years (Jianwei et al., 2016). Tea is composed by different types of many components. These
components have various effects depending upon the amount of tea ingested and its quality.
Tea has various useful properties which are helpful for human body. In Indian, every person
are regular user of Tea, but they are not aware of all the presented permitted materials in tea
which play harmful effect. Different brands and non-brands Tea Powder are available which
contain different types of not permitted materials. Tea is divided into10 types, Anti-Acidity
Tea, Anti-Aging Herbal Tea, Anti-Cough Tea, Green Tea, Herbal Tea, Lemongrass Tea,
Moringa Green Tea, Organic Tea, Orthodox Tea, and Slimming Tea (Muthumani and
Kumar, 2007).
Tea leaves are probably the earliest and most consumed herbs. Black tea is processed from
the young tender shoot of Camellia sinensis (L.) O. Kuntze. Black tea is produced from tea
plant after a series of physical and chemical reactions in the various tea processing
procedures (Xiaoli et al., 2012). It is the most widely consumed fluids next to water.
1
Approximately worldwide annual production of dry leaves and consumption reaches up to
1.8 million tons and 40 L per year, respectively (Seetohul et al., 2006).Tea quality mainly
depends on the variety of leaf, growing environment, plucking standard, plucking interval
and plucking season, manufacturing methods, size of ground tea leaves and infusion
preparation. Quality is measured on the basis of liquor brightness, briskness, color, aroma
and flavor and leaf appearance (Ramadurai, 2000; Astill et al., 2001).Tea leaf is
distinguished by its remarkable content of methylxanthines and polyphenol and they are
predominantly responsible for those unique properties of tea that account for its popularity as
beverage. Taste, flavor, aroma color, brightness and astringency in tea infusions are
influenced by polyphenols, caffeine, sugars, organic acids, amino acids and volatile flavor
compounds (Obanda et al., 2004).The tea plant Camellia sinensisis is produced in Southeast
Asia, but is currently cultivated in over 30 countries around the world. C. sinensisis the
species of plant whose leaves and leaf buds are used to produce the tea, is of the genus
Camellia, a genus of flowering plants in the family Theaceae. The Tea is consumed
worldwide, although in greatly different amounts; it is generally accepted that, next to water,
tea is the most consumed beverage in the world, with per capita consumption of less than120
mL/d (Katiyar et al., 1996).
The fresh tea leaves are usually used for tea manufacturing and are harvested by hand
plucking or mechanical plucking. Compared to mechanical plucking, hand plucking is more
labor intensive and time consuming and less efficient, but with higher uniformity. The well
known high quality green teas are mostly produced from hand-plucking fresh tea leaves from
China. According to the different ways of processing, especially the extent of fermentation,
2
tea is usually divided into three basic types: green tea (non-fermented), oolong tea (semifermented) and black tea (fully fermented). (Balentine, 2007)
Alternatively, with the combination of the ways of processing and the characteristic quality
of manufactured tea, tea is classified into six types: green tea, yellow tea, dark tea (containing
brick tea and pu-erh tea), white tea, oolong tea and black tea. The so-called fermentation in
tea processing is not the anaerobic breakdown of energy-rich compound (as a carbohydrate to
carbon dioxide and alcohol or to an organic acid), but in essence is mainly the oxidative
polymerization and condensation of catechins catalyzed by endogenous polyphenol oxidase
and peroxidase (Katiyar and Mukhtar 2006).
The oxidation products such as theaflavins and therubigins contribute to tea color and taste of
the black tea. Moreover, tea quality is also determined by the processing techniques
employed. The three basic types of tea; green, oolong and black have different quality
characteristics, including aroma, taste and color, and appearance. Of the total amount of tea
produced and consumed in the world, 78% is black, 20% is green, and less than 2% is oolong
tea. Black tea is consumed primarily in Western countries and in some Asian countries,
whereas green tea is consumed primarily in China, Japan, India, and a few countries in North
Africa and the Middle East. Oolong tea production and consumption are confined to
southeastern China and Taiwan (Katiyar and Mukhtar 2006). Kukicha (twig tea) is also
harvested from C. sinensis, but uses twigs and stems rather than leaves. Tea currently is the
hot topic in both nutritional and therapeutic research worldwide. This is not so because tea is
the most preferred drink after water, but because of the presence of crucial therapeutic
compounds in tea which are more bio-stable and direct acting than those found in other
plants. The activities of these compounds are so all pervading that they are virtually broad
3
spectrum in their actions. Besides, the natural integration of aromatic and therapeutic
compounds in tea is a rather unique attribute (Sakanaka, et al., 2008).
1.2
Unbranded tea of interest
1.2.1
Green Tea
Green tea is consumed as a popular beverage worldwide, particularly in Asian countries like
China, Korea and Japan. There is hardly any other food or drink reported to have as many
health benefits as green tea. The Ancient Chinese Proverb ‘Better to be deprived of food for
three days, than tea for one’ day indicates the importance of tea in the day-to-day life of
Chinese. The Chinese have known about the medicinal benefits of green tea since ancient
times, using it to treat everything from headaches to depression (Shimoda et al., 2014). The
chemical composition of green tea varies with climate, season, horticultural practices and
position of the leaf on the harvested shoot. The major components of interest are the
polyphenols. The major polyphenols in green tea are flavonoids. The four major flavonoids
in green tea are the catechins, epicatechin (EC), epigallocatechin (EGC), epicatechin gallate
(ECG) and epigallocatechin gallate (EGCG). Epigallocatechin gallate is viewed as the most
significant active component. The leaf bud and first leaves are richest in EGCG. The usual
concentration of total polyphenols in dried green tea leaves is , 8–12%. Other compounds of
interest in dried green tea leaves include gallic acid, quercetin, kaempferol, myricetin, caffeic
acid and chlorogenic acid (Liang et al., 2003).
1.2.2
Black Tea
Black tea is produced from tea plant after a series of physical and chemical reactions in the
various tea processing procedures (Xiaoli et al., 2012). It is the most widely consumed fluids
4
next to water. Approximately worldwide annual production of dry leaves and consumption
reaches up to 1.8 million tons and 40 L per year, respectively (Seetohul et al., 2006).
1.3
Significance of the Study
This research will provide new sights into the benefits of tea (Camellia synesis) in the body
and some effects of heavy metals. Through this research, the community will further realize
promoting the drinking of tea, especially green tea, as a preventive measure against various
diseases. People and medical institutions may also consider tea as an alternative supplement
against some disease such as; anti cancer, skin treatment, anti fungal, cholesterol reduction
etc. moreover, the analysis that is presented in the study will convey valuable information for
future research that will explore the various benefits of tea plants (Camellia synesis) and the
content of heavy metals in the tea.
1.4
Statement of the Problems
This study was conducted to obtain comprehensive information on heavy metals in most
current green and black varieties of tea within Kaduna metropolis. The level of seven heavy
metals including Ca, Mg, Cd, Pb, and Zn was monitored in green and black tea within
Kaduna metropolis
5
1.5
Aim
To Analyze Some Metals in Unbranded Tea samples Within Kaduna Metropolis,
1.6
Objectives
1. To investigate the concentration of some metals (Ca, Mg, Cd, Pb, and Zn) in unbranded tea
samples (green tea and black tea) purchased within Kaduna metropolises.
2. To compare the various concentrations of these metals (Ca, Mg, Cd, Pb and Zn) in green and
black tea the unbranded samples
3. To find out whether the levels of these metals are within the tolerable limit suggested by the
(World Agencies and Organization)
6
CHAPTER TWO
LITERATURE REVIEW
2.0
Metals
“Metals” are natural elements characterized by their rather high atomic mass and their high
density. Although typically occurring in rather low concentration, they can be found all
through the crust of our planet. Commonly, a density of at least 5 g cm−3 is used to define a
heavy metal and to differentiate it from other, “light” metals. Other, broader definitions for
“heavy metals” require an atomic mass higher than 23 or an atomic number exceeding 20;
these definitions are highly error prone and confusing. Both alternative definitions cause the
inclusion even of nonmetals; resorting to the atomic mass criterion, the maximum number of
elements classified as “ metals” rockets high to 99 out of the in total 118 building blocks of
our universe. Looking at the periodic table of elements, we learn that metals sensustricto
(according to the density criterion) occupy the lion’s share, namely, columns 3–16, of the
periods 4 to 6, encompassing the transition metals, post-transition metals, and lanthanides
(Mitscher et al., 2007). Some metals like copper, selenium, or zinc are essential trace
elements, with functions indispensible for various biological processes also driving the entire
human metabolism. The metal cobalt, acting as the central atom in the vitamin B12 complex,
is a key player in the reductive branch of the propionic acid fermentation pathway; without
this special metal compound, the gourmet would have to do without the unique lavor of
Emmentaler cheese. Many metals are of outstanding technological significance, e.g.,iron,
zinc, tin, lead, copper, tungsten, etc. Recently, different metals act as the central atom of
artificially designed “bioinorganic” catalysts for special chemical transformations (Okubo,
and Juneja 2017).
7
Moreover, among them we find precious noble elements like gold, silver, iridium, rhodium,
or platinum. On the other hand, many of them, e.g., mercury, cadmium, arsenic, chromium,
thallium, lead, and others, classically represent the “dark side of chemistry”; they exert toxic
effects already at low concentration (Sakanaka and Kim 2007).
2.1
Metal in Tea
Exposure to various metal containing components of tea varied widely and may have varying
health implications. Depending on the origin of tea leaves, metals accumulation can be
derived naturally by soil contamination, use of pesticides and fertilizers. Some trace metals
Cr, Fe, Co, Ni, and Zn are essential for growth of organisms, while other heavy metals Pb,
Cd, Hg and As are not only biologically non essential, but toxic (Stensvold et al., 2012). A
very important biological property of metals is their tendency to bioaccumulations.
Bioaccumulation is therefore essential in hazard evaluation strategies. For example,
calculation of percent available of Aluminum (Al) and Zinc (Zn) in tea consumed by human
showed that tea can provide 37.2% of the daily dietary intake of Al, the percent available for
absorption in the intestine is only 1.78% for overall mean concentration. Similarly, daily
dietary intake of Zn was 2.13% while percentage available for absorption in the intestine was
0.72%. Thus chronic metal toxicity is often characterized by tissue/organ damage resulting in
mortalities which are related to secondary physiological disturbances. The extent of
physiological disturbances depends upon uptake and bioaccumulation of metals (Toda et al.,
2008).
8
2.2
Toxic Effect Of Metals
A toxic metal is any relatively dense metal or metalloid that is noted for its potential toxicity,
especially in environmental contexts. The term has particular implementation to cadmium,
mercury lead and arsenic, all of which appear in the world agencies organizations, list often
(10) chemicals of major public concern. Other examples include selenium, copper,\chromium,
cobalt, nickel, manganese, copper, zinc, antimony, silver and thallium (Sakanaka et al.,
2010). Metals are dangerous because they tend to bioaccumulate. Also bio accumulation can
refer to an increase in the concentration of a chemical composition in the environment,
(Muktar and Ahmad 2000). Metals toxicity can result in damaged or reduced mental and
central nervous function, kidney, liver and other vital organs. Metal toxicity depends on
several factors including the dose, route of exposure and chemical species, as well as the
ase, sender, genetics and nutritional status of-exposed individuals. Although it is
acknowledged that heavy metals have many adverse effects and last for a long period of
time.' Long-term exposure may result in slowly progressing physical, muscular and
neurological degenerative processes that mimic Alzheimer's Disease, Parkinson's Disease
muscular dystrophy and multiple sclerosis. Allergies are not uncommon and repeated.
Long-term contact with some metals or their compounds may even cause cancer (Mitscher et
al., 2007). Metal toxicity has proven to be a major threat and there are several health risks
associated with it. The toxic effect of these metals, even though they do not have any
biological role, remain present in some human bodies as well as affect its proper
functioning. They sometimes acts as a pseudo element of the body while at certain times
they may even interfere with metabolic processes. Few metals, such as aluminum, can be
removed through elimination activities, while some metals get accumulated in the body and
food chain, exhibiting a chronic nature. Various public health measures have been
9
undertaken to control, prevent and treat metals toxicity occurring at various levels. Such as
occupational exposure, accidents and environmental factors. Metal toxicity also depends on the
duration of exposure, i.e. Acute or chronic. This can lead to various disorders and can also
result in excessive damage due to oxidative-stress induced by free radical formation (Thelle
2015). Toxic metals to a large extent are disposed in the environment through industrial
effluents, organic wastes, refuse burning, transport and power generation. Particulate
metallic pollutants are ultimately washed, and leached into surface of water, air is also a route
of environmental pollution (Tamura et al., 2019). Metals containing industrial effluents
constitute a major source of metallic pollution of hydrosphere (Tamura et al., 2019).
2.3
Metal analysis
Classification of heavy metals analysis involves well-established techniques, such as wet
chemical methods (gravimetric, titrimetric, colorimetric, etc.), coupled plasma/atomic
emission spectrometry (ICP/AES), inductively coupled plasma with mass spectrometric
detection (ICP/MS), or atomic absorption spectroscopy (AAS). Moreover, diverse ion
selective electrodes are frequently reported for metal determination (Toda et al., 2008).
Currently, new, robust, sensitive, selective, inexpensive, and fast optical, chemical, and
biological. Sensory systems are currently in status of development. Such advances in
analytical chemistry are currently tightly connected to nanotechnology (Shimoda et al.,
2014). Moreover, so-called lab-on-paper sensors were also developed for heavy metal
analysis as demonstrated for quantification of mercury, silver, copper, cadmium, lead,
chromium, and nickel. This sensor, operated by an immobilized enzyme, is an example for
so-called biosensors, which synergistically combine the scientific fields of biotechnology and
microelectronics; such “biosensors” consist of an immobilized biological component in
10
combination with a transducer. As a very recent technology, so-called genetically encoded
fluorescent sensors can be used for monitoring metals inside biological cells and were
already assessed for determination of metals like zinc, copper, lead, cadmium, mercury, or
arsenic (Moncrieff 2017)
2.4
Heavy metal of Interest
2.4.1
Lead (Pb)
Lead is a harmful environmental pollutant which has high toxic effects to many body organs.
Even though Pb can be absorbed from the skin, it is mostly absorbed from respiratory and
digestive systems. Pb exposure can induce neurological, respiratory, urinary, and
cardiovascular disorders due to immune modulation, oxidative, and inflammatory
mechanisms. Furthermore, Pb could disturb the balance of the oxidant–antioxidant system
and induce inflammatory responses in various organs. Exposure to Pb can produce alteration
in physiological functions of the body and is associated with many diseases (Yokozawa et
al., 2015; Zayuan et al., 2008; Kao and P’eng 2015). Pb is highly toxic which has adverse
effects on the neurological, biological, and cognitive functions in the bodies. The
international level-of-concern for Pb poisoning is 10 μg/dl in the blood (Burki, 2012;
Kianoush et al.,2013). Adulteration of opium with Pb has been considered as a threat to
human health in recent years (Katiyar and Mukhtar 2006).
2.4.2
Cadmium (Cd)
Cadmium (Cd), although rare, occurs naturally in soil and minerals such as sulfide, sulfate,
carbonate, chloride, and hydroxide salts as well as in water. High levels of Cd in water, air,
and soil can occur following industrial activities which could be a substantial human
11
exposure to Cd. Moreover, the ingestion of contaminated food will cause major exposure to
Cd. Cadmium exposure may also occur through smoking, which is capable of elevating
blood and urine Cd concentrations. Presence of Cd in contaminated water could disturb the
necessary mechanisms in the body, possibly resulting in short-term or long-term disorders
(Lean et al., 1999; lee et al., 2008; Kohlmeier et al., 2007). Cd is classified by the
International Agency for Research on Cancer (IARC) as carcinogenic to humans (Group 1)
(Katiyar et al., 2013). Occupational exposure to Cd may occur in alloy, battery, and glass
production and in electroplating industries. Due to the importance of the subject, Cd level in
the air is routinely monitored in some countries (Hara, et al., 2015b). Rice, grains, and sea
food have been found to be polluted by Cd (Hara, 2015a); nonetheless, after oral intake, a
small portion of Cd is absorbed. Tragically, the outbreak of Itai-itai disease in Japan was due
to the mass Cd contamination of food and water supplies (Fujita 2014).
Other Metals of Interest
2.4.3
Zinc
Zinc is a transition metal with the following characteristics: period 4, group IIB, atomic
number 30, atomic mass 65.4, density 7.14 g cm−3, melting point 419.5°C, and boiling point
906°C. Zinc occurs naturally in soil (about 70 mg kg−1 in crustal rocks), but Zn
concentrations are rising unnaturally, due to anthropogenic additions. Most Zn is added
during industrial activities, such as mining, coal, and waste combustion and steel processing
(Hara et al., 2015c). Many foodstuffs contain certain concentrations of Zn. Drinking water
also contains certain amounts of Zn, which may be higher when it is stored in metal tanks.
Industrial sources or toxic waste sites may cause the concentrations of Zn in drinking water
to reach levels that can cause health problems. Zinc is a trace element that is essential for
12
human health. Zinc shortages can cause birth defects. The world’s Zn production is still on
the rise which means that more and more Zn ends up in the environment. Water is polluted
with Zn, due to the presence of large quantities present in the wastewater of industrial plants.
A consequence is that Zn-polluted sludge is continually being deposited by rivers on their
banks. Zinc may also increase the acidity of waters. Some fish can accumulate Zn in their
bodies, when they live in Zn-contaminated waterways. When Zn enters the bodies of these
fish, it is able to bio magnify up the food chain. Water-soluble zinc that is located in soils can
contaminate groundwater. Plants often have a Zn uptake that their systems cannot handle,
due to the accumulation of Zn in soils. Finally, Zn can interrupt the activity in soils, as it
negatively influences the activity of microorganisms and earthworms, thus retarding the
breakdown of organic matter (Drwaosti et al., 2007).
2.4.4
Calcium
Calcium ranks fifth in the order of abundance of elements in earth’s crust, the percentage
being estimated at 3.64. Calcium does not occur free in nature being an active element. It
occurs largely in the form of carbonates and sulphates. As carbonates, it occurs in the form of
lime stone, chalk, calcite, marble, Iceland spar, dolomite stalactite, stalagmite etc. and
sulphate, it occurs in the form of Gypsum and its anhydride form calcium also occurs as a
phosphate in the phosphorite rock. CaSiO3 in many complex rocks, fluoride in the form of
fluorspar (Caf2). (Hara et al., 2015d).
13
2.4.5
Magnesium
Magnesium is the eighth most abundant element in the Earth's crust (Hara et al., 2015e) and
the fourth most common element in the Earth (after iron, oxygen and silicon), making up
13% of the planet's mass and a large fraction of the planet's mantle. It is the third most
abundant element dissolved in seawater, after sodium and chlorine (Ishigami and Hara 2013).
Magnesium occurs naturally only in combination with other elements, where it invariably has
a +2 oxidation state. The free element (metal) can be produced artificially, and is highly
reactive (though in the atmosphere it is soon coated in a thin layer of oxide that partly
inhibits reactivity – see passivation). The free metal burns with a characteristic brilliant-white
light. The metal is now obtained mainly by electrolysis of magnesium salts obtained from
brine, and is used primarily as a component in aluminum-magnesium alloys, sometimes
called magnalium or magnelium. Magnesium is less dense than aluminium, and the alloy is
prized for its combination of lightness and strength (Diker et al., 2015).
This element is the eleventh most abundant element by mass in the human body and is
essential to all cells and some 300 enzymes. Magnesium ions interact with polyphosphate
compounds such as ATP, DNA, and RNA. Hundreds of enzymes require magnesium ions to
function. Magnesium compounds are used medicinally as common laxatives, antacids (e.g.,
milk of magnesia), and to stabilize abnormal nerve excitation or blood vessel spasm in such
conditions as eclampsia (Diker and Hascelik 2017).
2.5
Chemical Constituents of Tea
The chemical composition of tea leaves has been thoroughly studied. The main constituents
of tea leaves belong to the polyphenol group accounting for 25 to 35% on a dry weight basis
(Balentine, 2017; Hara et al., 2015d). The polyphenols in tea mainly include the following
14
six groups of compounds: flavanols, hydroxyl-4-flavanols, anthocyanins, flavones, flavanols
and phenolic acids. Important and characteristic tea polyphenols are the flavanols of which
catechins (flavan-3-ols) are pre- dominant and the major ones these are:
(-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)- epigallocatechin (EGC), (-)epigallocatechin gallate (EGCG), (+)-catechin (C), and (+)-gallocatechin (GC) (Hara et al.,
2015a; Liang et al., 2003; Mukhtar and Ahmad 2000). These compounds contribute to the
bitterness, astringency and sweet aftertaste of tea beverages (Hara et al., 2015b).
Tea contains also flavanols, mainly quercetin, kaempferol, myricetin, and their glycosides. In
black tea, the oxidation of polyphenols during processing leads to the formation of catechins
and gallic acid complexes such as theaflavins, theaflavin acids, thearubigins or theasinensis,
and of proanthocyanidin polymers (Balentine et al., 2017; Hara et al., 2015c; Lee et al.,
2008). Methylxanthines are present with 2 to 4% as caffeine and a small amount of
theophylline and of theobromine (Hara et al., 2015a). Tea contains many amino acids, but
theanine, specific to the tea plant, is the most abundant, accounting for 50% of the total
amino acids. Amino acid degradation is involved in the biogenesis of the tea aroma
(Balentine et al., 2017). Chlorophyll, carotenoids, lipids and volatile compounds are not
major constituents in a tea brew but they also play an important role in the development of
the aroma (Hara et al., 2015d). Volatile fractions of tea leaves have been studied in detail and
more than 600 different molecules have been isolated (Hara et al., 2015c; Shimoda et al.,
2014). These include terpenoids and degradation products of amino acids, carotenoids and
linoleic acid (Hara et al., 2015a). Tea also contains carbohydrates, vitamins E, K, A, low
levels of B vitamins and vitamin C (in green tea only). Tea also provides useful amounts of
potassium, manganese and fluoride ions to the diet (Hara et al., 2015d).
15
2.5.1
Polyphenols
Polyphenols are a large family of naturally occurring organic compounds characterized by
multiples of phenol units. They are abundant in plants and structurally diverse. Polyphenols
include flavonoids, tannic acid, and ellagitannin, some of which have been used historically
as dyes and for tanning garments. (-) Epicatechin (EC), (-) epicatechin gallate (ECG), (-)
epigallocatechin (EGC), (-) epigallocatechin gallate (EGCG), (+) catechin (C), (+)
gallocatechin (GC), theflavin, theflavin-3-O-gallate, theflavin-3’-O-gallate, theflavin-3,3’-diO-gallate, isotheflavin, theflavin isomer, theflavic acid, epitheflavic acid, epitheflavic acid3;-Ogallate, etc (Weisburger 2000)
2.5.2. Minerals
Mineral constitutes about 4 to 9% of the inorganic matter of tea (fluorine, potassium,
aluminum, iodine, selenium, nickel, and manganese.(Hara et al., 2015).
2.6
Aroma, Taste and Color of Tea
These characteristics are developed during the manufacturing process after the harvesting of
tea flushes. Tea flush is generally a reference to young shoots of tea that consists of terminal
bud and two adjacent leaves. In fresh tea flush there exists a wide variety of non-volatile
compounds such as polyphenols, flavonols and flavonol glycosides, flavones, phenolic acids
and depsides, amino acids, chlorophyll and other pigments, carbohydrates, organic acids,
caffeine and other alkaloids, minerals, vitamins and enzymes (Hara et al., 2015d).
16
2.6.1
Aroma of Made Tea
Aroma is one of the critical aspects of tea quality which can determine acceptance or
rejection of a tea before it is tasted. Early research on tea aroma can be traced back over 170
years (Mulder, 1838), but progress on a more scientific basis has been achieved by the
application of modern analytical techniques since 1960’s, when gas chromatography was
widely used, especially when capillary column techniques are available (Agarwal et
al.,2013).
2.6.2. Taste of Made Tea
Taste of food is mainly composed of five basic sensations; that is, sweetness, astringency,
sourness, bitterness and umami (Tamura et al., 2019). A delicious cup of tea infusion is an
ingenious balance of various taste sensations. Astringency is a drying, puckering sensation in
the mouth that affects the whole of the tongue more or less uniformly (Lea and Arnold 2018).
Bitterness is usually unpleasant, but sometimes desirable in moderate amounts, and is
perceived predominantly at the back of, and sometimes along side of, the tongue (Moncrieff,
2017).
2.6.3
Color of Made Tea
Shade of color in made tea and the infusion color are two attributes besides aroma and taste
in the evaluation of various kinds of tea. Green tea infusion contains no highly colored
products formed by the oxidation of polyphenolic compounds, and the desired color is
greenish or yellowish green without any trace of red or brown color. The green color is the
main shade of color in the infused leaf and the infusion of green tea. It is mainly determined
17
by the chlorophyll content and the ratio of chlorophyll A which is dark green and chlorophyll
B which is yellowish-green in color.
2.7
Biological Activity of Tea Chemical Constituents
2.7.1. Tea Polyphenols and Antioxidant Activity
Antioxidants protect the body against the damaging effects of free radicals produced
naturally within the body. But over production of these free radicals due to environmental
pollution, smoking or physiological disorders may disrupt the body’s own antioxidant system
and resulting in the production of free radicals far in excess of what is good for health. An
imbalance between free radical production and natural antioxidants could cause damage to
proteins and DNA, the genetic material within the cells.. A plethora of evidence suggests
strong antioxidant potentials of tea flavonoids in containing or suppressing the production of
excess free radicals (Weisburger, 2000).
2.7.2
Tea Polyphenols and the Risk of Cancer
Abundant experimental and epidemiologic evidence accumulated mainly in the past decade
from several centers worldwide provides a convincing argument that polyphenolic
antioxidants present in green and black tea can reduce cancer risk in a variety of animal
tumor bioassay systems (Katiyar and Mukhtar 2006; Dreaosti et al., 2007; Kohlmeier et al.,
2007).
2.7.3
Tea Polyphenols and the Risk Coronary Heart Disease
Coronary heart disease is most prevalent in the Western world, probably as a result of the
lifestyle in this part of the world, which includes a diet high in saturated fats and low physical
18
activity, and the large proportion of the population who smoke cigarettes and have high
blood pressure. A variety of epidemiologic studies showed the preventive effect of green tea
consumption against atherosclerosis and coronary heart disease (Weisburger 2006; Thelle
2015). Tea consumption has also been shown to reduce the risk of high blood cholesterol
concentrations and high blood pressure (Stensvoldet al., 2012).
2.7.4
Antibacterial and antiviral effects of tea
Green tea catechins have demonstrated antibacterial activity against both “gram-positive”
and “gram-negative” bacteria which can be harmful to humans. Tea extracts inhibit enteric
pathogens such as Staphylococcus aureus, S. epidermis, Plesiomonas shigelloides (Toda et
al., 2009), Salmonella typhi, S. tiphimurium, S. enteritidis, Shigella flexneri, S. disenteriae
and Vibrio cholerae, V. parahaemolyticus (Mitscher et al., 2007; Toda et al., 2009; Toda et
al., 2008), Campylobacter jejuniand C. coli (Diker et al., 2015) but are not effective against
Escherichia coli, Pseudomonas aeruginosa or Aeromonas hydrophila (Toda et al., 2009).
Black and green tea extracts can also kill Helicobacter pylori associated with gastric, peptic
and duodenal ulcer diseases (Diker et al., 2017). However, the tea concentration used in these
studies exceeded normal human consumption levels. Tea polyphenols can selectively inhibit
the growth of clostridia and promote the growth of bifid bacteria in human large intestine.
The bacterial balance in intestinal microflora may be important for the prevention of colon
cancer (Okubo et al., 2017). Antimicrobial activity against cariogenic and periodontal
bacteria has been reported. Tea polyphenols inhibit Streptococcus mutans (Sakanaka et al.,
2009), S. sobrinus (Sakanaka et al., 2010) and Porphyromon as gingival is, bacteria
responsible for tooth decay (Kakuda et al., 2014; Sakanaka et al., 2008). They hinder the
synthesis of insoluble glucans by glucosyltransferases, and the sucrose-dependant bacteria
19
cell adherence to tooth and epithelium, by reducing collagenase activity (Mitscher et al.,
2007; Sakanaka et al., 2010, 2007).
2.7.5
Anti-Inflammatory Effects of Tea
In several studies from our laboratory and elsewhere, the polyphenolic fraction from green
tea was shown to protect against inflammation caused by certain chemicals, such as 12Otetradecanoylphorbol- 13- acetate, a principal irritant in croton oil (Katiyaret al., 2012,
2013, 2006), or by ultraviolet radiation B (290 to 320 nm) (Agarwal et al., 2013). Green tea
has also been shown to be effective against the immunosuppression caused by ultraviolet
radiation B (Katiyar et al., 2005a, 2006). In addition, green tea polyphenols have shown
protection against cytokines induced by tumors (Katiyar et al., 2005b).
2.7.6
Diabetes and Renal Failure Effects of Tea
Diabetes is associated with high blood glucose content. Green and black tea extracts can
decrease significantly the blood glucose level of aged rats by reducing the glucose absorption
and uptake in different ways (Zeyuan et al., 2008). It is reported that tea polyphenolics
inhibit alpha amylase activity in saliva, reduce the intestinal amylase activity which in turn
lowers the hydrolysis of starch to glucose and reduces glucose assimilation (Hara et al.,
2015f). It was also found that tea reduces the glucose mucosal uptake because
polysaccharides inhibit the glucose absorption and the diphenylamine of tea promotes its
metabolism (Zeyuan et al., 2008).
Polyphenols can also decrease digestive enzyme activity and reduce glucose absorption
(Zeyuan et al., 2008). They decrease uremic toxin levels and the methyl guanidine of
hemodialysis patients (Sakanaka et al., 2007). Polyphenols also protect against oxidative
20
stress associated with late complications in diabetes pathology and are useful to maintain a
balance between pro- and anti-oxidants in the organism (Zeyuanet al., 2008). Tea
consumption is associated with an increase in urine volume and electrolyte elimination,
notably sodium, along with a blood pressure decrease (systolic and diastolic values) in
hypertensive adenine-induced rats (Yokogoshi et al., 2015).
2.7.7
Functionalities of tea and Tea Polyphenols in Animal Models
Administration of green or black tea to animal models of oxidative stress and oxidative
stress-associated pathologies (for example, cancer, inflammation and atherosclerosis), elicits
a range of responses that are consistent with the proposal that tea flavonoids or their
metabolites are not only bio-available, but are also active in affecting cellular processes in
vivo, by mechanisms that may be related to their antioxidant functionalities (Weisburgar
2006).
2.7.8
Effects of Tea Polyphenols Against Other Diseases
Many studies have shown that the consumption of tea or its polyphenols can afford
protection against diseases other than cancer and coronary heart disease. A few of these
studies are as follows: Weisburger (2006) showed that tea is protective against stroke; Fujita
(2014) and Kao et al. (2015) reported that tea consumption lowers the risk of osteoporosis;
Imai et al., (2015) reported protection against liver disease; Ishigami et al., (2013) reported
the inhibition of dental caries by tea. Tea polyphenols are perhaps the most abundant and
efficient antioxidants and are the star players in the immune system, regulating a delicate
balance between the immune cell functions by modulating their secretion of specific
cytokines. Green tea (-)-epigallocatechin gallate and tea ext. have shown immunostimulatory
21
effects in mice, impairing the migration of macrophages/monocytes and neutrophils to the
inflammatory lesions by regulating the secretion of interleukin-10 (IL-10), interferon-γ (IFNγ), tumor necrosis factor α (TNF-α) and IL-12. Tea polyphenols play interesting roles in the
development and activation of immune cells, thereby modulating their Th1/Th2 balance.
Ethylamine, a degradation product of L-theanine, has shown remarkable effects in priming
human Vδ2Vγ2 T cells and further enhancing their memory to abrogate microbial infections
(Katiyar et al., 2005).
22
CHAPTER THREE
3.0
METHOD
3.1
Preparation of standard solution
Standard solutions of 1000 ppm were prepared for each of the heavy metals; the desired
concentrations required for the calibration of standard graph for each element were also
prepared from stock solution by serial dilution. The absorbance of each standard solution was
determined using Atomic Absorption spectrophotometer (AAS). The Calibration graph of
each element was prepared by plotting the absorbance against concentration in parts per
million (ppm).
3.1.1 Preparation of zinc chloride (ZnCl2) standard solution
In the preparation of 1000 ppm standard solution, 2.09g of ZnCl2 was measured into 1000
cm3 volumetric flask and make up to the mark with distilled water. The desired concentration
of 1ppm, 2ppm, 3ppm, 4ppm and 5ppm solutions were prepared by serial dilution; 0.1 mL,
0.2 mL, 0.3 mL, 0.4 mL and 0.5 mL of the prepared stock solution (1000 ppm) were
measured into 100 mL volumetric flask and diluted with distilled water to the mark
respectively.
3.1.2 Preparation of Calcium chloride (CaCl2) standard solution
In the preparation of 1000 ppm standard solution, 2.21g of CaCl2 was measured into 1000
cm3 volumetric flask and make up to the mark with distilled water. The desired concentration
of 1ppm, 2ppm, 3ppm, 4ppm and 5ppm solutions were prepared by serial dilution; 0.1 mL,
0.2 mL, 0.3 mL, 0.4 mL and 0.5 mL of the prepared stock solution (1000 ppm) were
23
measured into 100 mL volumetric flask and diluted with distilled water to the mark
respectively.
3.1.3 Preparation of cadmium chloride (CdCl2) standard solution
In the preparation of 1000 ppm standard solution, 2.117 g of CdCl2was measured into 1000
cm3 volumetric flask and make up to the mark with distilled water. The desired concentration
of 1ppm, 2ppm, 3ppm, 4ppm and 5ppm solutions were prepared by serial dilution; 0.1 mL,
0.2 mL, 0.3 mL, 0.4 mL and 0.5 mL of the prepared stock solution (1000 ppm) were
measured into 100 mL volumetric flask and diluted with distilled water to the mark
respectively.
3.1.4
Preparation of lead Chloride (PbCl2) standard solution
In the preparation of 1000 ppm standard solution,2.205 g of PbCl2was measured into 1000
cm3 volumetric flask and make up to the mark with distilled water. The desired concentration
of 1ppm, 2ppm, 3ppm, 4ppm and 5ppm solutions were prepared by serial dilution; 0.1 mL,
0.2 mL, 0.3 mL, 0.4 mL and 0.5 mL of the prepared stock solution (1000 ppm) were
measured into 100 mL volumetric flask and diluted with distilled water to the mark
respectively.
3.1.5
Preparation of Magnesium chloride (MgCl2) standard solution
In the preparation of 1000 ppm standard solution, 2.271g of MgCl2was measured into 1000
cm3 volumetric flask and make up to the mark with distilled water. The desired concentration
of 1ppm, 2ppm, 3ppm, 4ppm and 5ppm solutions were prepared by serial dilution; 0.1 mL,
0.2 mL, 0.3 mL, 0.4 mL and 0.5 mL of the prepared stock solution (1000 ppm) were
24
measured into 100 mL volumetric flask and diluted with distilled water to the mark
respectively.
3.2
Sampling Collection and Sampling Preparation
Tea bags such as argagai tea, boost tea, highland tea, highland BP tea, were obtained from
four (3) different markets within Kaduna Metropolis namely: Central market, kawo market
and Bakin dogo.
25
Figure 1.1: Nigeria showing Kaduna State
Source: Kaduna Polytechnic Cartographic Map Library (2022).
26
Figure 1.2: Kaduna Metropolis showing Sample Points. (Kaduna Polytechnic Cartographic
Map Library 2022).
3.3
Material and Method
All reagents were strictly prepared from chemicals of analytical reagent grade (analar) and
deionized water during the analysis, unless stated otherwise. The plastical container and the
27
glass ware were thoroughly washed with detergent solution after which were rinsed
thoroughly with tap water, deionized water and with analytical sample.
3.4
List of Apparatus and Instrument
Measuring cylinder
Beaker
Conical flask
Volumetric flask
Funnel
What man filter paper
Sample bottle
Hot plate
Atomic absorption spectrophotometer (AAS)
3.5
List of Reagent
Nitric acid (HNO3)
Hydrogen peroxide (H2O2)
Deionize water
28
S/N
SAMPLE NAME
CODE
LOCATION
TYPE
1
Argagai tea
ARG
KM,C.M, B.D
Unbranded
2
Boost tea
BST
KM,C.M, B.D
Unbranded
3
Highland tea
HL
KM,C.M, B.D
Unbranded
4
Highland B.P tea
HLBP
KM,C.M, B.D
Unbranded
Key
Kawo market =K.M
Central market =C.M
Bakindogo
=B.D
3.6
Methodology
3.6.1
Sample Ashing and Digestion
All digestion vessels and associated glass wares were washed with detergent and nitric acid
and rinsed with the deionize water 3 times prior to use. The glass ware were then dried in an
oven at a temperature of 40oc (Radojevic and Baskin 1999)
5grams of tea samples was 'weighed and charred in a fume cupboard. The crucible and the
content were ashed in a muffle furnace at a temperature of 550°C for four (4) hours. After
which is cooled in a desiccator and transferred into a clean beaker. 10ml of HNO3 was added
to the beaker and its content then 5ml of hydrogen peroxide was also added and was heated
to almost dryness then was allowed to cool. 50ml of distilled water was added to the content
and was filtered into a 100ml volumetric flask with What man filter paper and made up to a
29
mark with distilled water and transferred into a properly labeled sampling bottle. This was
repeated for all samples to be analyzed. The metals such as Ca, Pb, Cd, Mg, and Zn were
determined using Atomic Absorption Spectrophotometer (AAS).
3.7
Instrumentation
Atomic Absorption Spectrophotometer (AAS) is a technique for measuring quantities of
chemical elements present in the samples by measuring the absorbance radiation. This is
done by measuring the spectral produced when the sample is excited by radiation. The atom
absorbed ultraviolet or visible light and make transition to higher energy levels.
Atomic Absorption methods measure the amount of photons of light that are absorbed by the
sample. A detector measure the wavelengths of light transmitted by sample and compared the
wavelength absorbed, which originally passed through the sample. A signal processor then
integrates the changes in wavelength absorbed which appears in the readout as peaks of
energy required for an electron to leave an atom known as ionization energy.
Each atom has its own distinct pattern of wavelength energy. The configuration of electrons
in the outermost shell enables the qualitative analysis of the sample. The concentration is
calculated based on the Beer Lambert Law.
3.7.1. Beer Lambert Law
The Beer-Lambert Law states that to the concentration of the analyzed sample. The
concentration which is usually not obtained is usually determine from the calibration curve
obtained using standard of known concentration.
30
3.8
Basic Principle
The selectivity in atomic absorbance spectrophotometer is very important since eachelement
has a different set of energy levels and give rise to a narrow absorption lines.
Hence, the selection of monochromator is vital to obtain a linear calibration curve.
Themonochromator is a very important part of an atomic absorbance spectrophotometer
because it is used to separate the thousands of lines generated by all the elements in the
sample. The light selected by the monochromator is directed into a detector typically a
Photo-multiplier tube, whose function is to convert the light into an electrical signal
proportional to the light intensity.
31
CHAPTER FOUR
4.0.
RESULT
Result obtained from the analysis of elemental content in unbranded tea samples from
different markets within Kaduna metropolis were presented in Tables below. The
concentration of each metals obtained in the Tea samples move through the various process
are presented in Table 4.0-4.2 below the concentration value of Zn, Mg, Ca, were
significantly different in the different sample location, Cd was not detected in all the sample
and Pb was detected in some samples in relatively small amount.
Table 4.0: Metals concentration (mg/g) in unbranded tea obtained in central market.
ELEMENTS (mg/g)
S/N
SAMPLES
Zn
Pb
Cd
Mg
Ca
1
BST
4.58±0.1
0.60±0.10
ND
11.24±0.10
96.52±0.10
2
HL
3.56±0.1
ND
ND
11.39±0.10
99.31±0.10
3
ARG
8.44±0.10
0.59±0.10
ND
10.60±0.43
84.21±0.10
4
HLPBP
2.68±0.10
ND
ND
11.60±0.10
113.11±0.10
KEY
BST = BOOST TEA
HL= HIGHLAND TEA
ARG= ARGAGAI TEA
HLBP= HIGHLAND B.P
ND = NOT DETECTED
32
Table4.1: Metals concentration (mg/g) in unbranded tea obtained in Bakin Dogo
ELEMENTS (mg/g)
S/N
Sample
Zn
Pb
Cd
Mg
Ca
1
BST
2.84±0.01
0.66±0.10
ND
10.89±0.10
79.85±0.10
2
HL
2.59±0.10
0.633±0.10
ND
11.43±0.10
101.38±0.10
3
ARG
3.16±0.10
ND
ND
10.61±0.10
78.68±0.10
4
HLPBP
1.89±0.10
ND
ND
10.73±0.10
93.78±0.10
KEY
BST = BOOST TEA
HL= HIGHLAND TEA
ARG= ARGAGAI TEA
HLBP= HIGHLAND B.P
ND = NOT DETECTED
33
Table 4.2: Metals concentration (mg/g) in unbranded tea obtained in Kawo Market
ELEMENTS (mg/g)
S/N
SAMPLES Zn
Pb
Cd
Mg
Ca
1
BST
2.71±0.10
0.82±0.11
ND
10.63±0.10
71.57±0.10
2
HL
2.8±0.10
0.26±0.10
ND
11.62±0.1
11674±0.10
3
ARG
3.16±0.10
ND
ND
10.61±0.1
81.27±0.10
4
HLPBP
2.78±0.10
0.80±0.10
ND
11.15±0.10
103±0.10
KEY
BST = BOOST TEA
HL= HIGHLAND TEA
ARG= ARGAGAI TEA
HLBP= HIGHLAND B.P
ND = NOT DETECTED
34
CHAPTER 5
5.0.
DISCUSSION, RECOMMENDATION, CONCLUSSION.
5.1.
Discussion
The result showed that Cadmium, Zinc and Mg which are part of microelements that are
necessary as component of enzymes involved in major metabolic process where present in all
the samples analyzed
Cadmium was not detected in all the samples while lead was detected in some samples but in
relatively small amount.
It was also observed that calcium has higher concentration than other heavy metals present in
the samples. (table4.0- 4.2)
Also, the result showed that cadmium and lead concentration in all the sample did not exceed
the permissible level of 1.5mg/kg and 2.5mg/kg respectively(CAC,2003). The FAO/WHO
(1999) has set a limit for heavy metal intake based on body weight. For an average adult
(60kg body weight) the daily dietary intake of cadmium and lead re 40-50µg and 214µg per
day(WHO,1997). Cadmium does accumulate within the kidney and liver for a long period of
time (MCLaughlin et al, 1999). Health implications of high cadmium intake are lung
damage, reduction in sperm count and renal tubular damaged (ibeto and Okoye, 2009). The
highest lead concentration was found in sample 1 and 4 with concentration of 0.82±0.11 and
0.80±0.10 while sample 2record the lowest concentration.(Table 4.2) .
Calcium, Magnesium and Zinc were found to be present in all the samples and the result
were found to be in line with Iwegbue(2012). While cadmium was not detected in all the
35
samples and Lead was detected in sample 2ande 4(Table4.0), sample 3and 4 (Table 4.1), and
sample 3 (Table4.3) The result reveals that all the heavy metals concentration in tea sample
(Argagai, Boost, Highland and Highland B.P.) Concentration were below the permissible
limits (JEFCA,2010).
It is important to note at this point that even through Cd, Pb, Mg, Zn and Ca fell within
acceptable limits, a continuous bioaccumulation might be a problem later, hence need for
their consistent monitoring to forestall heavy metals intoxication.
36
Figure 0.1
Figure above shows the concentration of all the metals (Zn, Pb,Cd,Mg and Ca) in all the
unbranded tea samples purchased in central market, it could be seen from the chart that
HLBP has the highest concentration of Ca with mean concentration 113.11±0.10 and
ARG record the lowest mean concentration of 84.21±0.10. (Table 4.0). From the chart it is
seen that Cd was not detected and Pb was in relatively small amount. The second metal with
highest concentration is Mg with almost same concentration (Table 4.0). Then Zn was
analyzed and sample 3 (ARG) has the highest mean concentration of 8.4± 0.10 and sample 4
(HLBP) recorded the lowest mean concentration of Zn 2.68±0.10 (table 4.0).
37
Figure 0.2
Figure 2.0 shows the concentration of all the metals (Zn, Pb,Cd,Mg , Ca) in all the unbranded
tea samples purchased in bakin dogo market. From the chart, it could be seen that HL
sample has the highest concentration of Ca with mean value of 101.38±0.10 and ARG record
the lowest value with mean concentration of 78.68±0.10 (Table 4.1). Just like the other chart
fig 1.0 Ca too was not detected in the samples here (table 4.1) . Pb was not detected in
sample 3 and 4 and it was detected in 1 and 2 in relatively small amount with mean
concentration. Of 0.66±0.10, and 0.63±0.10 respectively (table 4.1). Mg
recorded the
second metal with the highest value and sample 3 (ARG) recorded the lowest value
10.61±0.10 and sample 2 (HL) record the highest mean concentration 11.43±0.10 and
sample 4 having the lowest mean concentration of 1.89±0.10. (Table 4.1).
38
Figure 3.0
The above chart shows the concentration of all the metals (Zn, Pb,Cd,Mg,Ca) in all the
samples purchased in kawo market. From the chart HL recorded the highest concentration of
Ca, 116.74±0.10 and BST sample recorded the lowest mean concentration 71.5±0.11 and
sample 2 record the lowest concentration 0.26±0.10 (table 4.2). Mg
recorded the second
metal with highest value and sample 2 and 3 has the highest concentration 11.62±0.10
respectively and sample 3& 1 recorded the lowest concentration 10. 61±0.10 and
11.62±0.10 respectively. Zn was also analyzed with sample 3 having the highest mean conc.
3.16± 0.10, 2.78±0.10, 2.87±0.10 respectively.(table 4.2).
39
The absent of Cd and Pb in all the samples, makes it essential for consumption as Cd causes
lung damage, reduction in sperm count and renal tubular damage (Ibeto and okoye, 2009 ).
While high level of lead causes anemia, weak accumulation of lead can cause death. Calcium
is a nutrient that all living organisms need, including humans. It is the
most abundant
mineral in the body and it is vital for bone health. Calcium people also need Vitamin D as
this vitamin helps the body absorb and exposes to sunlight and calcium help to maintain
strong bones muscle contraction cardiovascular system E.T.C. magnesium also play some
vital role just as calcium plays. Then Zn support the immune system, it enables the body to
make protein and DNA, also contributes to wound healing and plays a role in childhood
growth and development and also has antioxidant property. (Tim. Newman, 2020).
The discussion above shows that these tea samples ARG, HL, BST, HLBP are good for
consumption and those not have side effect but it regular consumption may cause the
accumulation of the metals which can cause effect to the human health.
5.3
Conclusion
This study was able to establish that all metals tested were below permissible limit in all the
samples analyzed. These indicated that the samples analyzed. These indicated that the
samples were not contaminated and pose no damage to human health, though consistent
intake of these products can be hazardous due to the bio-accumulative property of heavy
metals. The results also showed that calcium, magnesium and zinc which are part of the
microelements necessary as components of enzymes involved in major metabolic process
were present in all the samples analyzed. It is recommended that constant monitoring should
be carry out during manufacturing in order to avoid the levels exceeding permissible limits.
40
5.4
Recommendation
 Based on the findings of this project, it recommended that government public health workers
at all levels should encourage farmers in farming tea in high quantity as it is very important
and metals in it are within the permissible limit.
 Government should encourage citizens in taking tea as both the green tea and black tea
contain polyphenolic ant-oxidant that can reduce cancer risk and coronary heart disease.
 Government should discourage famers from cultivating on lands where there is high human
activities.
 Finally, government and other concern bodies are needed to educate farmers on the health
implications of these metal and need for the use of good agricultural practice is require for
farming.
41
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48
Appendix
Concentration of the selected heavy metals (mg/g) in Central Market Concentration of the
selected heavy metals (mg/g) in Bakin Dogo Concentration of the selected heavy metals
(mg/g) in Kawo Market * Heavy Metals
Heavy Metals
Concentration of Concentration of
Concentration of the
the selected heavy the selected heavy selected heavy metals
metals (mg/g) in
metals (mg/g) in
(mg/g) in Kawo
Central Market
Bakin Dogo
Market
Mean
4.81675
2.62100
2.87950
N
12
12
12
Zn
Std. Deviation
2.299219
.496960
.198848
Std. Error of Mean
.663727
.143460
.057402
Mean
.19625
.06883
.37458
N
12
12
12
Pb
Std. Deviation
.436013
.669140
.514574
Std. Error of Mean
.125866
.193164
.148545
Mean
-.14700
-.14575
-.13025
N
12
12
12
Cd
Std. Deviation
.087922
.086668
.086950
Std. Error of Mean
.025381
.025019
.025100
Mean
11.21525
10.91350
11.00350
N
12
12
12
Mg
Std. Deviation
.398973
.338869
.442298
Std. Error of Mean
.115174
.097823
.127680
Mean
98.28775
88.42000
93.18075
N
12
12
12
Ca
Std. Deviation
10.727392
9.978818
18.559257
Std. Error of Mean
3.096731
2.880637
5.357596
Mean
22.87380
20.37552
21.46162
N
60
60
60
Total
Std. Deviation
38.543301
34.817634
37.258730
Std. Error of Mean
4.975919
49
4.494937
4.810081
Sample
Mean
N
Boost
Highland
tea
Argagai
Highland
Bp
Total
Std. Deviation
Std. Error of
Mean
Mean
N
Std. Deviation
Std. Error of
Mean
Mean
N
Std. Deviation
Std. Error of
Mean
Mean
N
Std. Deviation
Std. Error of
Mean
Mean
N
Std. Deviation
Std. Error of
Mean
Report
Concentratio Concentratio
n of the
n of the
selected
selected
heavy metals heavy metals
(mg/g) in
(mg/g) in
Central
Bakin Dogo
Market
22.56140
18.81480
15
15
Concentration of the
selected heavy metals
(mg/g) in Kawo Market
17.11427
15
38.503807
31.846496
28.457964
9.941640
8.222730
7.347815
22.77640
15
39.853792
23.17980
15
40.697550
26.27360
15
47.026140
10.290205
10.508062
12.142097
20.73880
15
33.140741
18.43280
15
31.442517
18.91180
15
32.534030
8.556902
8.118423
8.400250
25.41860
15
45.602308
21.07467
15
37.869742
23.54680
15
41.398869
11.774465
9.777925
10.689142
22.87380
60
38.543301
20.37552
60
34.817634
21.46162
60
37.258730
4.975919
4.494937
4.810081
50
Concentration of the
selected heavy metals
(mg/g) in Central Market
Concentration of the
selected heavy metals
(mg/g) in Bakin Dogo
Concentration of the
selected heavy metals
(mg/g) in Kawo Market
Heavy metals
Error
Total
Heavy metals
Error
Total
Heavy metals
Error
Total
ANOVA
Sum of
Squares
86321.654
1327.924
87649.578
70419.457
1104.332
71523.790
78110.076
3794.489
81904.565
51
df
Mean Square
F
Sig.
4
55
59
4
55
59
4
21580.414
24.144
893.818
.000
17604.864
20.079
876.790
.000
19527.519
283.046
.000
55
59
68.991
Post Hoc Tests
Multiple Comparisons
LSD
Dependent (I) Heavy (J) Heavy
Mean
Variable
Metals
Metals
Difference (I-J)
Zn
Pb
Concentrati
on of the
selected
heavy
Cd
metals
(mg/g) in
Central
Market
Mg
Ca
Zn
Concentrati
on of the
selected
heavy
Pb
metals
(mg/g) in
Bakin
Dogo
Cd
Std.
Error
Sig.
95% Confidence Interval
Lower
Upper Bound
Bound
.60040
8.64060
.94365
8.98385
-10.41860
-2.37840
-97.49110
-89.45090
Pb
Cd
Mg
Ca
4.620500*
4.963750*
-6.398500*
-93.471000*
2.005994
2.005994
2.005994
2.005994
.025
.016
.002
.000
Zn
Cd
Mg
Ca
Zn
Pb
Mg
Ca
Zn
-4.620500*
.343250
-11.019000*
-98.091500*
-4.963750*
-.343250
-11.362250*
-98.434750*
6.398500*
2.005994
2.005994
2.005994
2.005994
2.005994
2.005994
2.005994
2.005994
2.005994
.025
.865
.000
.000
.016
.865
.000
.000
.002
-8.64060
-3.67685
-15.03910
-102.11160
-8.98385
-4.36335
-15.38235
-102.45485
2.37840
-.60040
4.36335
-6.99890
-94.07140
-.94365
3.67685
-7.34215
-94.41465
10.41860
Pb
Cd
Ca
Zn
Pb
Cd
Mg
Pb
Cd
Mg
Ca
Zn
Cd
Mg
Ca
Zn
Pb
Mg
Ca
11.019000*
11.362250*
-87.072500*
93.471000*
98.091500*
98.434750*
87.072500*
2.552167
2.766750
-8.292500*
-85.799000*
-2.552167
.214583
-10.844667*
-88.351167*
-2.766750
-.214583
-11.059250*
-88.565750*
2.005994
2.005994
2.005994
2.005994
2.005994
2.005994
2.005994
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
.000
.000
.000
.000
.000
.000
.000
.169
.136
.000
.000
.169
.907
.000
.000
.136
.907
.000
.000
6.99890
7.34215
-91.09260
89.45090
94.07140
94.41465
83.05240
-1.11390
-.89932
-11.95857
-89.46507
-6.21823
-3.45148
-14.51073
-92.01723
-6.43282
-3.88065
-14.72532
-92.23182
15.03910
15.38235
-83.05240
97.49110
102.11160
102.45485
91.09260
6.21823
6.43282
-4.62643
-82.13293
1.11390
3.88065
-7.17860
-84.68510
.89932
3.45148
-7.39318
-84.89968
52
Zn
Pb
Cd
Ca
Zn
Pb
Cd
Mg
Pb
Cd
Mg
8.292500*
10.844667*
11.059250*
-77.506500*
85.799000*
88.351167*
88.565750*
77.506500*
2.504917
3.009750
-8.124000*
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
1.829334
3.390937
3.390937
3.390937
.000
.000
.000
.000
.000
.000
.000
.000
.463
.379
.020
4.62643
7.17860
7.39318
-81.17257
82.13293
84.68510
84.89968
73.84043
-4.29067
-3.78584
-14.91959
11.95857
14.51073
14.72532
-73.84043
89.46507
92.01723
92.23182
81.17257
9.30051
9.80534
-1.32841
Ca
Zn
Cd
Mg
Ca
Zn
Pb
Mg
Ca
-90.301250*
-2.504917
.504833
-10.628917*
-92.806167*
-3.009750
-.504833
-11.133750*
-93.311000*
3.390937
3.390937
3.390937
3.390937
3.390937
3.390937
3.390937
3.390937
3.390937
.000
.463
.882
.003
.000
.379
.882
.002
.000
-97.09684
-9.30051
-6.29076
-17.42451
-99.60176
-9.80534
-7.30042
-17.92934
-100.10659
-83.50566
4.29067
7.30042
-3.83333
-86.01058
3.78584
6.29076
-4.33816
-86.51541
Zn
8.124000* 3.390937
Pb
10.628917* 3.390937
Cd
11.133750* 3.390937
Ca
-82.177250* 3.390937
Zn
90.301250* 3.390937
Pb
92.806167* 3.390937
Ca
Cd
93.311000* 3.390937
Mg
82.177250* 3.390937
*. The mean difference is significant at the 0.05 level.
.020
.003
.002
.000
.000
.000
.000
.000
1.32841
3.83333
4.33816
-88.97284
83.50566
86.01058
86.51541
75.38166
14.91959
17.42451
17.92934
-75.38166
97.09684
99.60176
100.10659
88.97284
Mg
Ca
Zn
Pb
Concentrati
on of the
selected
heavy
Cd
metals
(mg/g) in
Kawo
Market
Mg
53