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Vol. 3 (2) Apr Jun2012 www.ijrpbsonline.com 943

International Journal of Research in Pharmaceutical and Biomedical Sciences ISSN: 2229-3701

_________________________________________ResearchArticle

Determination of Cadmium, Copper, Nickel, Lead in Some Tea

Samples in India

Sushama R. Ambadekar1

*, Sangeeta Parab2

and Amit Bachankar2

1J ai Hind College, Churchgate, Mumbai, Maharashtra, India.

2Department of Chemistry, Analytical Chemistry Section, Institute Of Science, Mumbai,

Maharashtra, India.

__________________________________________________________________________________

ABSTRACT

Tea, a leaf extract of the plant Camellia sinensis, is the second most consumed beverage in the world, with an

estimated 18-20 billion cups consumed daily and, for instance, an estimated average consumption of 1

L/person/day in the United Kingdom. The intake of food contaminated by heavy metals is harmful to human

health and several countries have imposed food laws to restrict the presence of heavy metal concentration in

food and beverages. The main sources of heavy metals in plants are their growth media, nutrients, agro inputs

and soil. Other sources may include pesticides and fertilizers. Tea plays an important role in improvingbeneficial intestinal microflora, as well as providing immunity against intestinal disorders and in protecting cell

membranes from oxidative damage. Ingestion of large amounts of tea may cause nutritional and other

problems because of the caffeine content and the strong binding activities of tea polyphenols, although there

are no solid data on the harmful effects of tea consumption. More research is needed to elucidate the biologic

activities of green and black tea and to determine the optimal amount of tea consumption for possible health-

beneficial effects. The aim of this study was to determine the quantitative profile in terms of nonessential and

potentially toxic metals in the tea and hence the further work carried out analysis of trace metals in the five

different popular tea samples used in the region. The metals analysed were Cu, Cd, Pb and Ni . The data

generated from five different brands (T1,T2,T3,T4,T5) of tea samples and compared with Prevention of Food

Adulteration (PFA) limit and World Health Organisation(WHO) permissible limit.

Key Words: leaf extract, toxic metals, oxidative damage, health-beneficial effects.

INTRODUCTION

Tea is the agricultural product of the leaves, leaf

buds, and internodes of the Camellia sinensis plant,

prepared and cured by various methods. "Tea" also

refers to the aromatic beverage prepared from thecured leaves by combination with hot or boiling

water, and is the common name for the Camellia

sinensis plant itself. Tea is one of the most popularbeverages in the world and its health benefits havebeen well documented. Stagg and Millin (1975)

have emphasized the therapeutic action of tea1.The

intake of food contaminated by heavy metals is

harmful to human health and several countries have

imposed food laws to restrict the presence of heavymetal concentration in food and beverages

10. Tea

leaves are source of mineral elements such as zinc,

manganese, iron, copper, magnesium, titanium,

aluminum, strontium, bromine, sodium, potassium,phosphorous, iodine and fluorine. The tea infusion

contains very little protein, vitamins and

carbohydrates but may be a source of essentialdietary metals and metal binding polyphenols

2.

Srinivasan Subbiah, Manikandan Natarajan, Nair

Muralidharan Narayan, Selvasundaram Rajagopal(2008) noted that contaminated phosphatic and zinc

fertilizers were the sources of Cd in tea. Potassic

fertilizers, phosphatic fertilizers, NPK blends,

manganese, zinc, boron and magnesium sourcescontain lead

2. Tea plays an important role in

improving beneficial intestinal microflora, as well

as providing immunity against intestinal disordersand in protecting cell membranes from oxidativedamage. Tea also prevents dental caries due to the

presence of fluorine. The role of tea is well

established in normalizing blood pressure, lipid

depressing activity, prevention of coronary heart

diseases and diabetes by reducing the blood-glucose activity. Tea also possesses germicidal andgermistatic activities against various gram-positive

and gram negative human pathogenic bacteria

Food naturally contains copper. You eat and drinkabout 1 milligram (1/1,000 of a gram or 4/100,000

ounces) of copper every day. Generally, the amount

of copper in your body remains constant .Copper isessential for good health. However, exposure tohigher doses can be harmful. Intentionally high

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intakes of copper can cause liver and kidneydamage and even death. Food contains nickel and

is the major source of nickel exposure for thegeneral population. You eat about 170 micrograms

(g; 1 g=1 millionth of a gram) of nickel in your

food every day. After nickel gets into your body, itcan go to all organs, but it mainly goes to the

kidneys

5

.A small amount of the cadmium in food and water

(about 510%) will enter your body through the

digestive tract. Most of the cadmium that entersyour body goes to your kidney and liver and can

remain there for many years. Eating lower levels ofcadmium over a long period of time can lead to a

build-up of cadmium in the kidneys. If the levelsreach a high enough level, the cadmium in the

kidney will cause kidney damage. Your body doesnot change lead into any other form. The maintarget for lead toxicity is the nervous system, both

in adults and children. Lead exposure may alsocause weakness in fingers, wrists, or ankles. Lead

exposure also causes small increases in blood

pressure, particularly in middle-aged and older

peoples high levels of exposure to lead may cause

miscarriage. High-level exposure in men candamage the organs responsible for sperm

production5.

The aim of this study was to determine the

quantitative profile in terms of nonessential andpotentially toxic metals in the tea and hence the

further work carried out analysis of trace metals in

the different tea samples i.e. T1,T2,T3,T4,T5. Thisstudy will be useful for the appraisal of trace

elements and antioxidant components in variousteas, and it will also be of interest for people who

like drinking this beverage1.

EXPERIMENTAL

Five different samples of tea samples such asT1,T2,T3,T4,T5 were obtained from Sahakari

Bhandar, Kulaba, Mumbai-400032.TheConcentrated HNO3, HClO4 were of Merck IndiaPvt Ltd. Atomic Absorption Spectroscopy y(AAS)

standards solutions Cu, Ni and Cd of ThomasBaker Chemicals, Pvt. Ltd., Mumbai, and Pb from

S. D. Fine Chem. Ltd. Mumbai.All other Chemicals

used throughout the Experiment was A.R Grade.

The Double distilled water was obtained fromLABSIL INDIA LTD. Trace metal analysis was

performed on a Thermal Elemental AA Series

Spectrometer of SOLAAR working with Solaar AA

system. All the atomic absorption measurementswere carried out with a with a deuterium (D2) lamp

for background correction. Cu, Cd, Ni and Pb weredetermined by the flame AAS in an acetylene-air

flame. All glassware was washed with chromic acid

before analysis.Standard curves were constructed with solution of

known concentrations. The unknown samples wereanalyzed against the standard curve for measuring

the concentration of the desired metal. The

concentrations were expressed in microgram/gramof the sample.

METHOD USED

The 0.5g of the coarse powder of the sample beingexamined, transfer into a beaker. Add 5-10mL of

the mixture of nitric acid (HNO3) and perchloricacid (HClO4) (4:1), macerate overnight

7.10,13. The

sample was heated upto boil,if brownish black in

color, and add again a quantity of above mixture.Continuously heat till the solution becomes clear

and transparent. Then raise temperature, heat

continuously to thick smoke, till white smoke

disperse, the slaked solution becomes clear and

transparent or a little yellow. Cool and transfer itinto 50ml volumetric flask, wash the container with

2% nitric acid solution, add washing solution to thesame volumetric flask and dilute with the same

solvent to the volume, shake well5,9,18

. Similarlyblank were treated using the same acids to

minimize the error during the analysis.

HEAVY METAL MAXIMUM PERMISSIBLE

LIMITThe permissible limits of the heavy metals in tea

samples as per PFA (Prevention of Food

Adultration ). The permissible limit of copper is150 g/g under Prevention of Food Adulteration

Act, 1954 (PFA), India and of Lead is 10 g/g. Itis clearly evident that nickel mainly comes through

the foliar and soil application of low qualityfertilizers and micro nutrients. Since Ni is a toxicelement, not having any tolerance limit in tea, the

agro inputs used in tea fields will have to beanalyzed for heavy metal impurity

2.

The permissible limit of cadmium is 0.3 g/g in

food samples as per World Health Organisation and

Federal Drug Administration. The permisble limitof Nickel is 4 g/g according to Food and Nutrition

Board: Institute of Medicine, 2010.

Table 1: Experimental Conditions for the Detection of Heavy MetalsParameters HEAVY METALS

Wavelength

Cd Cu Ni Pb

228.8 nm 324.8 nm 232.0 nm 217.0 nm

Bandpass 0.5 nm 0.5 nm 0.2 nm 0.5 nm

Flame type Air-C2H2 Air-C2H2 Air-C2H2 Air-C2H2Fuel flow 1.0 L/min 0.8 L/min 0.9 L/min 1.1 L/min

Lamp current 50 % 50 % 75 % 75 %

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RESULTS AND DISCUSSION

The results obtained for analysis of tea samples by

the FAAS method are summarized in Table 2.The heavy metal concentration found in the tea

samples.

The concentration of Cd in tea leaves ranged from0.1195 g g

1to 2.1875 g g

1. The lowest value of

cadmium was found in T5and the highest in T1.In 2008, Subbiah, Manikandan Natarajan, Nair

Muralidharan Narayan, Selvasundaram Rajagopal,

were detected heavy metal content of black teasfrom south India, Food Control 19 (2008)[2].The

concentration of copper was found from0.62930.36 to 4.26351.59 g/g. The lowest

concentration of copper was found in T5 andhighest concentration was found in T2.

Nickel in tea was in the range from 8.7812 g/ g to21.5450 g/ g. The lowest value of Nickel wasfound in T3and the highest in T1 .The Pb content in

tea samples varied between 1.2000 g/g to 14.0212g/ g. The lowest value of lead was found in T1 and

the highest in T2tea sample.

CONCLUSIONS

There was wide variation in the heavy metalcontent of tea samples collected from the different

brands (T1,T2,T3,T4,T5) . The results indicated thatthe contents of Cd, Cu, Ni and Pb in tea were

different for the different agro climatic regions. A data generated for heavy metals in tea samples

from five different brands (T1,T2,T3,T4,T5) showed

that the levels of Cu were below the PFA limit of150 g/g. In this study, Pb content in all the tea

samples, except for Red Label Tea, was less than10 g/g, the limit prescribed under the PFA Act.

The permissible limit for nickel as per PFA Act is 5

g/g but the obtained results shows a higheramount of nickel in all the tea samples. The

ascending order of the amount of nickel present inthe five tea samples is shown as T2 and T3 > T4>

T4> T1. Except for T5 Tea sample, the amount ofcadmium was found to be higher than the other

four tea samples. The permissible limit forcadmium as per WHO is 0.3 g/g. We canconclude that the amount of cadmium, as shown

from the above bar graph,(Fig.1) is higher in T1followed by T2 which still had a higher amount of

cadmium than T3and T4 Tea was found to contain

less amount of cadmium but greater than the WHO

permissible limit.

Table 2

SamplesAmount of heavy metals in g/gm

Cd

MeanS.Da

Cu

MeanS.Da

Ni

MeanS.Da

Pb

MeanS.Da

T1 2.18750.88 1.17250.72 21.54500.42 1 .20000.46

T2 0.88120.04 4.26351.59 9.40560.28 14.02121.72

T3 0.57040.36 1.09390.32 8.78121.19 5.41121.57

T4 0.44470.14 3.52251.89 16.12101.55 10.02430.17

T5 0.11950.06 0.62930.36 18.37001.54 1 .38500.18a Standard deviation

Fig. 1: Concentrations of heavy metals were found in tea samples

T 1 T2 T3 T4 T5

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